| United States Patent Application |
20100104504
|
| Kind Code
|
A1
|
|
Echeverria Moran; Valentina
|
April 29, 2010
|
Materials and methods for diagnosis, prevention and/or treatment of stress
disorders and conditions associated with abeta peptide aggregation
Abstract
The subject invention concerns materials and methods for treating and/or
preventing diseases associated with accumulation of A.beta. peptide in
neural tissue. The subject invention also concerns materials and methods
for treating and/or preventing stress disorders, such as post-traumatic
stress disorder (PTSD). In one embodiment, a method of the invention
comprises administering a therapeutically effective amount of cotinine,
or a pharmaceutically acceptable salt thereof, to a person or animal in
need of treatment. The methods of the invention can be used to prevent
and/or treat Alzheimer's disease, Parkinson's disease, and/or Down's
syndrome. The subject invention also concerns compositions that comprise
cotinine, or a pharmaceutically acceptable salt thereof, and a
pharmaceutically acceptable carrier, diluent or adjuvant.
The subject invention concerns materials and methods for detecting and
diagnosing conditions associated with accumulation of A.beta. peptide in
neural tissue, such as Alzheimer's disease and Parkinson's disease, using
the chemical cotinine. In one embodiment, the method comprises
administering cotinine labeled with a detectable label to a person or
animal. The presence of labeled cotinine in neural tissue is then
determined. The level and/or location of cotinine can be analyzed and a
diagnosis made. The subject invention also concerns cotinine labeled with
a detectable label. In one embodiment, the cotinine is labeled with a
radioisotope that can be detected by Positron Emission Tomography (PET)
or single photon emission computed tomography (SPECT).
| Inventors: |
Echeverria Moran; Valentina; (Largo, FL)
|
| Correspondence Address:
|
SALIWANCHIK LLOYD & SALIWANCHIK;A PROFESSIONAL ASSOCIATION
PO Box 142950
GAINESVILLE
FL
32614
US
|
| Assignee: |
University of South Florida
Tampa
FL
United States Department of Veterans Affairs
Washington
DC
|
| Family ID:
|
42117703
|
| Appl. No.:
|
12/586681
|
| Filed:
|
September 24, 2009 |
Related U.S. Patent Documents
| | | | |
|
| Application Number | Filing Date | Patent Number | |
|---|
| | 61194064 | Sep 24, 2008 | | |
| | 61099746 | Sep 24, 2008 | | |
|
|
| Current U.S. Class: |
424/1.11 ; 424/1.81; 514/343; 546/278.4 |
| Current CPC Class: |
A61K 51/0455 20130101; A61K 31/4439 20130101; A61P 25/28 20180101; C07D 401/04 20130101; A61P 25/26 20180101 |
| Class at Publication: |
424/1.11 ; 514/343; 424/1.81; 546/278.4 |
| International Class: |
A61K 51/00 20060101 A61K051/00; A61K 31/4439 20060101 A61K031/4439; A61P 25/28 20060101 A61P025/28; A61P 25/26 20060101 A61P025/26; C07D 401/00 20060101 C07D401/00 |
Claims
1. A method for treating and/or preventing a disease or condition
associated with the accumulation and/or aggregation of Abeta peptide in
neural tissue, or for treating and/or preventing a disorder or condition
associated with Down's syndrome, or for treating and/or preventing a
stress disorder or condition, said method comprising administering an
effective amount of cotinine, or a composition comprising cotinine, or an
isomer or racemate thereof, or a pharmaceutically acceptable salt
thereof, to a person or animal.
2. The method according to claim 1, wherein said method further comprises
administering one or more drugs for the treatment or prevention of a
neurodegenerative condition.
3. The method according to claim 2, wherein said one or more drug is
donepezil (ARICEPT), galantamine (RAZADYNE), rivastigmine (EXELON),
memantine (AKATINOL), rasagiline (AZILECT), selegiline (ELDEPRYL), L-dopa
(LEVODOPA, SINEMET, PARCOPA, STALEVO, MADOPAR), carbidopa (LODOSYN), or
benserazide, or an isomer or analog thereof, or a pharmaceutically
acceptable salt thereof.
4. The method according to claim 1, wherein said method further comprises
administering one or more drugs for the treatment of a stress disorder or
condition.
5. The method according to claim 4, wherein said one or more drug is a
selective serotonin reuptake inhibitor (SSRI); a serotonin-norepinephrine
reuptake inhibitor (SNRI); a tricyclic antidepressants (TCA);
3,4-methylenedioxy-N-methylamphetamine (MDMA); propranolol; clonidine; or
ziprasidone.
6. The method according to claim 5, wherein said SSRI is citalopram,
escitalopram, fluvoxamine, paroxetine, or sertraline and/or said SNRI is
venlafaxine, desvenlafaxine, duloxetine, sibutramine, or milnacipran.
7. A method for inhibiting or preventing A.beta. oligomerization, or for
increasing activity or expression of dopamine- and cyclic AMP-regulated
phosphoprotein of 32 kDa (DARPP-32) and/or facilitating serotonin release
in neural tissue or a cell, said method comprising contacting a cell with
an effective amount of cotinine, or a composition comprising cotinine, or
a pharmaceutically acceptable salt thereof.
8. The method according to claim 7, wherein said cell is a cortical cell.
9. A method for detecting, diagnosing, and monitoring a condition
associated with the accumulation and/or aggregation of A.beta. peptide in
neural tissue, said method comprising administering detectably labeled
cotinine, or an isomer or racemate thereof, to a person or animal
10. The method according to claim 9, wherein said labeled cotinine is
detected using radioimaging.
11. The method according to claim 9, wherein the level or concentration
and/or location in neural tissue of said labeled cotinine is determined
and/or analyzed.
12. The method according to claim 9, wherein said labeled cotinine is
labeled with a radioisotope.
13. The method according to claim 12, wherein said radioisotope is
detectable by Position Emission Tomography (PET) and/or single photon
emission computed tomography (SPECT).
14. The method according to claim 13, wherein said radioisotope is
carbon-11, nitrogen-13, oxygen-15, fluorine-18, bromine-76, iodine-121,
technetium-99m, iodine-123, or indium-111.
15. The method according to claim 9, wherein the condition is Parkinson's
disease or Alzheimer's disease.
16. The method according to claim 9, wherein said labeled cotinine is
radiolabeled and administered at a dose of about 1 mCi per 70 kg of body
weight to about 100 mCi per 70 kg of body weight.
17. The method according to claim 9, wherein said labeled cotinine is
administered in a physiologically acceptable carrier, buffer, or diluent.
18. A cotinine molecule, or an isomer or racemate thereof, or a
pharmaceutically acceptable salt thereof, or a composition comprising
said cotinine molecule, wherein said cotinine is labeled with a
detectable label.
19. The cotinine molecule according to claim 18, wherein said cotinine is
radiolabeled.
20. The cotinine molecule according to claim 18, wherein said cotinine is
labeled with a radioisotope detectable by PET and/or SPECT.
21. The cotinine molecule according to claim 20, wherein said
radioisotope is carbon-11, nitrogen-13, oxygen-15, fluorine-18,
bromine-76, iodine-121, technetium-99m, iodine-123, or indium-111.
22. The cotinine molecule according to claim 18, wherein said composition
comprises a pharmaceutically acceptable carrier, diluent, or adjuvant.
23. The cotinine molecule according to claim 18, wherein said composition
comprises one or more other drugs useful in treating a neurodegenerative
condition, Down's syndrome, or a stress disorder.
24. The cotinine molecule according to claim 23, wherein said one or more
other drugs is donepezil (ARICEPT), galantamine (RAZADYNE), rivastigmine
(EXELON), memantine (AKATINOL), rasagiline (AZILECT), selegiline
(ELDEPRYL), L-dopa (LEVODOPA, SINEMET, PARCOPA, STALEVO, MADOPAR),
carbidopa (LODOSYN), benserazide, a selective serotonin reuptake
inhibitor (S SRI), a serotonin-norepinephrine reuptake inhibitor (SNRI),
a tricyclic antidepressant (TCA), 3,4-methylenedioxy-N-methylamphetamine
(MDMA), propranolol, clonidine, or ziprasidone, or an isomer or analog
thereof, or a pharmaceutically acceptable salt thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of U.S. Provisional
Application Ser. No. 61/194,064, filed Sep. 24, 2008, and U.S.
Provisional Application Ser. No. 61/099,746, filed Sep. 24, 2008, each of
which is hereby incorporated by reference herein in its entirety,
including any figures, tables, nucleic acid sequences, amino acid
sequences, and drawings.
BACKGROUND OF THE INVENTION
[0002] Post-traumatic stress disorder (PTSD) is a type of anxiety disorder
that manifests after exposure to a life-threatening traumatic event
(Kessler (2000); Kessler et al. (1995)). PTSD affects approximately 6.8%
of the American population and is caused by rape, assault, accidents or
combat (Kessler et al. (2005)). In 2004, a US army study of more than
3600 veterans returning from Afghanistan and Iraq found that the
percentage of veterans suffering from PTSD and related disorders, was
9.3% for those who served in Afghanistan and 17.1% for those who were
stationed in Iraq (Hoge et al. (2004)). Compared with normal individuals,
PTSD patients have a reported higher utilization of medical services
(Calhoun et al. (2002); Solomon and Davidson (1997)), and are at
increased risk for developing cardiovascular disease and cancer
(Boscarino (2006); Schnurr and Jankowski (1999)).
[0003] Tobacco consumption is directly associated with PTSD. Numerous
reports dealing with smoking among individuals with PTSD, mostly as a
result of combat related trauma, showed that smoking prevalence is higher
than in the normal population with rates ranging from 34% to 86%.
[0004] Alzheimer's disease (AD) is the main cause of dementia in the
elderly and a progressive degenerative disease of the brain associated
with advanced age. AD is characterized by the presence of extracellular
amyloid senile plaques in the brain mainly consisting of amyloid-beta
(Abeta or A.beta.) peptide (that is generated by proteolytic processing
of the trans-membrane protein amyloid precursor protein (APP)) and
neurofibrillary tangles composed of aggregated tau protein (a microtubule
associated protein). AD pathology is characterized at the neuronal level,
by synaptic loss and cell death of selected neuronal populations
(Echeverria and Cuello (2002)). There are approximately 17 million people
affected by the disease world wide, and it is estimated that by 2050
there will be approximately 25 million affected in the United States.
There are no effective therapeutic agents for this disease, new drugs and
potential cures are being intensely investigated. According to many
studies the aggregated form of A.beta. and not the monomeric form of the
peptide is toxic. One of the strategies being investigated as a potential
cure for AD is the search for molecules that are able to stop A.beta.
aggregation. Thus, it is important to be able to detect A.beta. peptide
in animal tissue.
[0005] Currently, a diagnosis of Alzheimer's disease is generally made
using a psychiatric evaluation in conjunction with magnetic resonance
imaging of central nervous system (CNS) for changes in morphology.
Definitive diagnosis of Alzheimer's disease can only be made by
post-mortem neuropathological examination of a patient's brain. Thus, it
would be beneficial to have a means for diagnosing and monitoring
Alzheimer's disease in a patient in vivo.
[0006] Down's syndrome (DS), also named as chromosome 21 trisomy, is a
genetic disorder caused by the presence of an extra 21st chromosome. DS
is characterized by impairment of cognitive abilities and physical
changes and other health problems such as a higher risk for congenital
heart defects, recurrent ear infections, obstructive sleep apnea, and
thyroid dysfunctions. The incidence of DS is estimated at 1 per 800 to
1,000 births. The adult patients with DS have much higher incidence of
Alzheimer's disease than non affected individuals. It has reported that
25% of persons with DS develop the disease by age 40, and the rate
increases dramatically to 65% after age 60. Post-Mortem, nearly all
adults that suffered from DS showed Alzheimer's disease pathology.
[0007] Tobacco smoke is composed of thousands of compounds, most of which
have deleterious actions on cell homeostasis resulting in toxic effects
over the cardiovascular, pulmonary and brain systems (Gallinat et al.
(2006); Yolton et al. (2005)). Despite all of these negative actions,
several studies suggest that smoking is protective against AD (Court et
al. (2005); Merchant et al. (1999); Birtwistle and Hall (1996)) and
Parkinson's disease (Hong et al. (2009)). The benefits of tobacco have
been attributed to nicotine, an alkaloid and a potent cholinergic agonist
present in tobacco (Doolittle et al. (1995); Levin (2002)). Nicotine has
anti-apoptotic actions by a mechanism dependent on nicotinic
acetylcholine receptors (nAChRs), and has neuroprotective activity
against A.beta. toxicity in vitro (Gahring et al. (2003)). Using the
transgenic mouse model of AD, Tg2576 (APPswe) (Hsiao et al. (1996)), it
has been shown that nicotine reduces the levels of A.beta. in the brain
and improves memory abilities in these mice (Nordberg et al. (2002);
Unger et al. (2005); Hellstrom-Lindahl et al. (2004)). However, the short
half-life, toxicity and potential negative effects in promoting tau
pathology of nicotine discouraged its use in therapeutics (Oddo et al.
(2005)).
[0008] Nicotine is metabolized to cotinine in the liver (Hammond et al.
(1991)), which has a longer half-life than nicotine (10-24 h vs. 2-3 h,
respectively) and similar cytoprotective activity (Terry et al. (2005)).
The molecular mechanisms underlying the protective actions of cotinine
are not well understood. Cotinine is a weak agonist at the nicotinic and
muscarinic ACh receptors (mAChR), and it does not have significant
cholinergic effects in the brain (Terry et al. (2005); Buccafusco et al.
(2007); Briggs et al. (1995)).
[0009] In search of a mechanism of tobacco protection against AD, the
effect of nicotine and cotinine on the aggregation of amyloidogenic
fragments of A.beta. peptides has been explored in previous studies
(Salomon et al. (1996); Szymanska et al. (2007); Kirschner et al.
(2008)). The first study reported by Salomon et al. (1996) showed by
using circular dichroism (CD) and ultraviolet spectroscopic techniques
that nicotine and also but at a less extent cotinine inhibited amyloid
formation by A.beta..sub.1-42 peptide. Also by using nuclear magnetic
resonance (NMR) analysis of the A.beta.-nicotine complex, they suggested
that the biologically active optical enantiomer of nicotine
(L-(-)-nicotine, S form) inhibited the conversion of the A.beta..sub.1-42
peptide from its soluble form into insoluble .beta.-sheet oligomers. The
effect was attributed to the interaction of the A.beta..sub.1-42 residues
His6, His13 and His14 via aromatic .pi.-.pi. and/or electrostatic
interactions with the pyrrolidine moieties of nicotine (Salomon et al.
(1996)).
[0010] In a recent study, x-ray fiber diffraction was used to screen
A.beta. aggregation inhibitors (Kirschner et al. (2008)). These studies
showed that A.beta..sub.17-28 fibril formation was not inhibited by
nicotine or cotinine whereas A.beta..sub.12-28 was, from this evidence,
the authors proposed that the binding of aromatic small molecules to the
histidines present in the A.beta. sequence 12-16 (VHHQK) may inhibit the
subsequent A.beta. oligomerization and interfibril aggregation (Kirschner
et al. (2008)).
BRIEF SUMMARY OF THE INVENTION
[0011] The subject invention concerns materials and methods for treating
and/or preventing diseases associated with the accumulation and/or
aggregation of A.beta. peptide in neural tissue. In one embodiment, a
method of the invention comprises administering a therapeutically
effective amount of cotinine, or a pharmaceutically acceptable salt
thereof, to a person or animal in need of treatment. The methods of the
invention can be used to treat Alzheimer's disease (AD) and Parkinson's
disease (PD). In one embodiment, the method is used to treat a person
having Down's syndrome.
[0012] The subject invention also concerns materials and methods for
treating and/or preventing stress disorders, such as post-traumatic
stress disorder (PTSD). In one embodiment, a method of the invention
comprises administering a therapeutically effective amount of cotinine,
or a pharmaceutically acceptable salt thereof, to a person in need of
treatment.
[0013] The subject invention also concerns compositions that comprise
cotinine, or a pharmaceutically acceptable salt thereof, and a
pharmaceutically acceptable carrier, diluent or adjuvant.
[0014] The subject invention also concerns materials and methods for
detecting, diagnosing, and monitoring conditions associated with
accumulation of A.beta. peptide in neural tissue, such as Alzheimer's
disease and Parkinson's disease. In one embodiment, a method of the
invention comprises administering detectably labeled cotinine to a person
or animal. The level or concentration and/or location of labeled cotinine
in neural tissue is then determined. The level of cotinine can be
analyzed and a diagnosis made. In one embodiment, the cotinine is labeled
with a radioisotope that can be detected by Position Emission Tomography
(PET). Detection of labeled cotinine via PET provides for in vivo
diagnosis and monitoring of a patient's condition. In one embodiment,
Dementia associated with Parkinson's disease can be predicted by
detection of labeled cotinine in striatum.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The patent or application file contains at least one drawing
executed in color. Copies of this patent or patent application
publication with color drawing(s) will be provided by the Office upon
request and payment of the necessary fee.
[0016] FIG. 1 shows survival of cortical cells exposed to cotinine as
assayed in an MTT assay.
[0017] FIGS. 2A-2C and 2B show cortical cells protected by cotinine as
assayed in an MTT assay.
[0018] FIGS. 3A and 3B show cotinine inhibits A.beta. oligomerization as
assayed by MTT assay.
[0019] FIGS. 4A and 4B show neuroprotective activity of cotinine is not
affected by the antagonist of the nAChR alpha-bungarotoxin and
mecamylamine.
[0020] FIG. 5 shows a dot blot using antibody 6E10.
[0021] FIGS. 6A and 6B show a Western blot.
[0022] FIGS. 7A-7C. Cotinine protects neurons against A.beta. toxicity.
Embryonic cortical neurons after 7 days in vitro (DIV) were treated with
5 .mu.M A.beta. either alone or with various concentrations of cotinine
(0.1, 1, 10 .mu.M). After 24 h cell viability was assessed using MTT
assay (FIG. 7A) and double calcein-AM and PI staining (FIG. 7B). The MTT
and calcein/PI staining values were normalized against control values
considered 100%. The results show that even in the absence of
pre-incubation with the peptide, cotinine decreased A.beta. toxicity when
added to the cell culture media. Scale bar=20 .mu.m. The values represent
the mean.+-.S.E.M., with significant difference with P<0.05 (*),
P<0.01 (**), P<0.001 (***), between vehicle mean and treated
samples mean.
[0023] FIGS. 8A-8C. Cotinine inhibits A.beta. oligomerization. 100 .mu.M
A.beta..sub.1-42 was subjected to oligomerization conditions in the
presence or absence of cotinine (100, 200, and 500 .mu.M) for 1-7 days at
room temperature and aliquots were analyzed using the anti-A.beta.
antibody 6E10 by Western blot and dot-blot immunoassays after 5 and 7
days (FIG. 8A) and by dot-blot immunoassays using 6E10 and the highly
specific anti-A.beta. antibody A11, after 2 and 6 days of incubation at
RT (FIG. 8B). The results clearly show that cotinine inhibits A.beta.
oligomerization as expressed as a decrease in the immunoreactivity for
the A11 antibody and an increase in the immunoreactivity for the 6E10
antibody. FIG. 8C: Chemical structure of cotinine (upper), and
A.beta..sub.1-42 peptide sequence used in our studies (lower).
[0024] FIGS. 9A-9E. AFM analysis of the effect of cotinine on
A.beta..sub.1-42 fibrillation. A 900 nm field of A.beta..sub.1-42 peptide
incubated at concentration 1 mM for 10 days at 37.degree. C. in the
absence (FIG. 9A) or presence (FIG. 9B) of cotinine 2 mM. The plot
represents the length of the A.beta. fibrils formed under the conditions
illustrated in FIGS. 9A and 9B. The difference in length of the
A.beta..sub.1-42 fibrils was considered significant with P=0.0228
(Student-t test) (FIG. 9C).
[0025] FIG. 10. x-ray analysis of the A.beta..sub.1-42 after
vapor-hydration of the lyophilized peptide. Intensity of x-ray scatter as
a function of distance from the center of the pattern. Weak reflections,
characteristics of .beta.-sheet structure, are apparent at .about.0.10
.ANG..sup.-1 and 0.21 .ANG..sup.-1, which correspond to the intersheet
(horizontal bar) and hydrogen-bonding (arrow) reflections. The intense,
broad band at 0.30-0.35 .ANG..sup.-1 (w) is from water in the
vapor-hydrated, lyophilized peptide. Inset, after 10 days incubation, a
vapor-hydrated, lyophilized A.beta..sub.1-42 solution shows more intense
spacing from the .beta.-conformation, suggesting the formation of more
aggregates.
[0026] FIGS. 11A-11D. Cotinine is neuroprotective by blocking A.beta.
aggregation/oligomerization. The results show the viability of 7 DIV
cortical cells exposed to pre-aggregated and fresh dissolved
A.beta..sub.1-42-cotinine solutions for 24 h at 37.degree. C. FIG. 11A)
MTT analysis of cell viability of cells treated with A.beta..sub.1-42
solutions that were pre-incubated for 3 h at 4.degree. C., and then added
to the cell culture media containing 10 .mu.M cotinine. FIG. 11B) MTT
analysis of the cell viability of cortical cells treated with
A.beta..sub.1-42 pre-incubated with ascending concentrations of cotinine
for 3 h at 4.degree. C. The results indicate that when cotinine is added
after a pre-aggregation step of the peptide it does not protect against
A.beta. toxicity, but when cotinine is pre-incubated with the
A.beta..sub.1-42 solution it is able to protect against toxicity. Plots
represent cell viability as percentage of vehicle-treated controls. The
results were considered significant with P<0.05 (*), and highly
significant P<0.001 (***) as evaluated using One-way ANOVA with Tukey
post test.
[0027] FIGS. 12A and 12B. Cotinine upregulates the levels of
BDNF-stimulated phospho-CREB in cortical cells. 7 DIV cortical cells were
treated with vehicle, 5 .mu.M A.beta. in the presence or absence of
cotinine (10 .mu.M) for 5 h and then treated with 100 nM BDNF for 1 h.
FIG. 12B: After treatment, cell extracts were analyzed by Western blot
for the levels of the BDNF-stimulated phosphorylation of CREB (lower
panel). The histogram (upper panel) represents the normalized levels of
expression of phospho-CREB (Serine 133). .beta.-tubulin was used as a
control of protein loading and transfer. The values represent significant
difference with P<0.5(*).
[0028] FIG. 13. Root Mean Square Deviations (RMSD) plotted against time
for the molecular dynamics (MD) trajectory of A.beta..sub.1-42-cotinine
complex.
[0029] FIGS. 14A-14D. (FIG. 14A) The most representative structure derived
from the 50 ns MD simulation on A.beta..sub.1-42-cotinine complex. (FIG.
14B) Specific interactions of cotinine at the A.beta..sub.1-42 binding
site. (FIG. 14C) ChemDraw representation of specific interactions of
cotinine at the A.beta..sub.1-42 binding site. (FIG. 14D) Distance
between the center of Tyr10 and pyridine nucleus of cotinine. The numbers
represents the distances in .ANG..
[0030] FIGS. 15A and 15B. Secondary structural assignment per residue as a
function of time: (FIG. 15A) for the free A.beta..sub.1-42 monomer. (FIG.
15B) For the A.beta..sub.1-42-cotinine complex
[0031] FIGS. 16A and 16B shows that cotinine stimulates BDNF-induced Arc
Expression in cortical neurons. Primary cortical neurons after 7 days in
vitro were stimulated with BDNF alone or BDNF plus cotinine for 2 h. Then
cells were washed with PBS and disrupted by sonication in lysis buffer.
Cell extracts were separated by SDS-PAGE and analyzed by Western blot
with antibodies against Arc and .beta.-tubulin, which was used as a
control (FIG. 16B). The histogram represents the mean.+-.SEM of
experiments performed in triplicate. Significance of the differences were
evaluated using Student's t test **highly significant (p<0.01). BDNF,
brain-derived neurotrophic factor.
[0032] FIGS. 17A-17D shows that cotinine selectively affects cell
signaling in primary cortical neurons. After 7 days in vitro, cortical
neurons were treated with BDNF (100 ng/ml) alone or BDNF plus cotinine
(10 .mu.M) for 1 h. After treatments, cells were lysed and whole cell
extracts were analyzed for the active forms of JNK and ERKs, pJNK and
pERK1/2 by Western blot.
[0033] FIG. 18 shows that cotinine enhanced the extinction of fear memory.
Mice (n=8, by condition) were treated with vehicle or cotinine (1 and 5
mg/kg/day) for 8 days and then subjected to Fear conditioning training as
described. After 24 hours (h) mice were tested for freezing behavior when
re-exposed to the same context (the chamber) every day for 6 consecutive
days.
[0034] FIGS. 19A-19C shows the effect of cotinine on basal anxiety levels
in mice in the elevated plus maze test. Mice were placed in an EPM
(Stoelting, Wood Dale, Ill., USA) made of grey plexiglas, consisting of
two opposite-facing open arms, two opposite-facing closed arms, and a
central area. Mice were placed at the end of one of the open arms facing
toward the central area before a 5-minute test session was begun. We
recorded the number of entries into the open and closed arms and assessed
the exploratory behavior of the mice. We utilized a video tracking
software that measures movement in each section of the maze in order to
determine the time the mice were mobile exploring the different arms.
Statistical significance was evaluated using One-way ANOVA with Tukey
posttest. ns, not significant.
[0035] FIGS. 20A-20C show that cotinine decreased fear-induced anxiety in
the elevated plus maze. Mice were trained for FC. After the retention
test, the mice were tested for anxiety levels in the EPM. The number of
entries into the open and closed arms and the exploratory behavior of the
mice were determined using a video tracking software that measures
movement in each section of the EPM. Statistical significance of the
differences between groups was evaluated using One-way ANOVA with Tukey
posttest. ns, not significant, * significant, P<0.05, ** highly
significant P<0.01.
[0036] FIG. 21 shows that treatment of mice with cotinine for two weeks
did not affect their sensorimotor abilities. At the end of the behavioral
testing for FC, mice treated for two weeks with vehicle, cotinine 1 mg/kg
and 5 mg/kg were tested in the rotarod as follows. The rotarod test was
performed in an apparatus consisting of a 3 cm in diameter rod that was
started at 4 rpm, accelerating up to 40 rpm for 5 min. Mice were tested
for the time spent on the rod during each trial for a total of four
trails per day. Testing during each trial was finished when the mouse
fell off the rod and onto a spring-cushioned lever. The results are
expressed as latency to fall in seconds (time spent on the rod) with 8
mice/group/treatment.
[0037] FIGS. 22A and 22B show that cotinine prevents the loss of reference
memory in the circular platform. Mice of 2.5 months of age were treated
or not with cotinine 2.5 mg/kg via gavage for two months and after tested
in the circular platform test. In this test the number of errors to
escape a 69 cm diameter circular platform containing 16 holes along its
perimeter was determined in a single daily trial (300 s maximum) over 8
days of testing. Only one hole leads to an escape box, which remains the
same for any given animal. To control for olfactory cures, the escape
hole was relocated after each animal's trial and the maze cleaned with a
dilute vinegar solution. Tg, transgenic Tg6799 mice, NT, control wild
type littermate mice. N=11 mice by group.
DETAILED DESCRIPTION OF THE INVENTION
[0038] The subject invention concerns materials and methods for treating
and/or preventing diseases associated with accumulation and/or
aggregation of Abeta peptide in neural tissue. The methods of the
invention can be used to treat and/or prevent neurodegenerative
conditions, such as Alzheimer's disease (AD) and Parkinson's disease
(PD). In one embodiment, a method of the invention comprises
administering a therapeutically effective amount of cotinine, or a
pharmaceutically acceptable salt thereof, to a person or animal in need
of treatment. In one embodiment, cotinine can be administered in
conjunction with other drugs for the treatment or prevention of
neurodegenerative conditions, including, for example, donepezil
(ARICEPT), galantamine (RAZADYNE), rivastigmine (EXELON), memantine
(AKATINOL), rasagiline (AZILECT), selegiline (ELDEPRYL), L-dopa
(LEVODOPA, SINEMET, PARCOPA, STALEVO, MADOPAR), carbidopa (LODOSYN), and
benserazide, or an isomer or analog thereof. Other neurodegenerative
conditions contemplated within the scope of the present invention
include, but are not limited to, dementia with Lewy bodies (DLB),
dementia pugilistica, Pick's disease, cerebral amyloid angiopathy, and
posterior cortical atrophy.
[0039] The methods of the invention can also be used to treat and/or
prevent disorders associated with Down's syndrome. In one embodiment, a
therapeutically effective amount of cotinine, or a pharmaceutically
acceptable salt thereof, is administered to a person having Down's
syndrome.
[0040] The subject invention also concerns methods for treating and/or
preventing stress disorders, such as PTSD. In one embodiment, a method of
the invention comprises administering a therapeutically effective amount
of cotinine, or a pharmaceutically acceptable salt thereof, to a person
or animal in need of treatment. In one embodiment, cotinine can be
administered in conjunction with other drugs for the treatment of stress
disorders, including, for example, monoamine oxidase (MAO) inhibitors;
antiepileptic drugs; selective serotonin reuptake inhibitors (SSRI), such
as citalopram, escitalopram, fluvoxamine, paroxetine, and sertraline;
serotonin-norepinephrine reuptake inhibitors (SNRI), such as venlafaxine,
desvenlafaxine, duloxetine, sibutramine, and milnacipran; tricyclic
antidepressants (TCAs); 3,4-methylenedioxy-N-methylamphetamine (MDMA);
propranolol; clonidine, and ziprasidone, or an isomer or analog thereof.
Methods of the invention can be used in combination with other therapies
for stress disorders, including, for example, various forms of
psychotherapy, yoga, and the like.
[0041] The subject invention also concerns compositions that comprise
cotinine, or a pharmaceutically acceptable salt thereof, and a
pharmaceutically acceptable carrier, diluent or adjuvant. In one
embodiment, a composition of the invention further comprises one or more
drugs or compounds useful in treating AD, PD, or PTSD. Cotinine has the
chemical structure:
##STR00001##
[0042] Isomers and racemates of cotinine are contemplated within the scope
of the methods and compositions of the present invention. In one
embodiment, cotinine is racemic cotinine. In another embodiment, cotinine
is the (-)-isomer (i.e., (-)-cotinine). In a further embodiment, cotinine
is the (+)-isomer (i.e., (+)-cotinine).
[0043] The subject invention also concerns methods for inhibiting or
preventing cell death resulting from A.beta. oligomerization. In one
embodiment, the method comprises contacting a cell with an effective
amount of cotinine, or a physiologically acceptable salt thereof In one
embodiment, the cell is a neural cell. In a specific embodiment, the cell
is a cortical cell. In one embodiment, the cell is contacted with
cotinine in vivo or in vitro.
[0044] The subject invention also concerns methods for inhibiting or
preventing A.beta. oligomerization in a cell. In one embodiment, the
method comprises contacting a cell with an effective amount of cotinine,
or a physiologically acceptable salt thereof In one embodiment, the cell
is a neural cell. In a specific embodiment, the cell is a cortical cell.
In one embodiment, the cell is contacted with cotinine in vivo or in
vitro.
[0045] The subject invention also concerns materials and methods for
increasing activity or expression of dopamine- and cyclic AMP-regulated
phosphoprotein of 32 kDa (DARPP-32) and/or facilitating serotonin release
in the brain. In one embodiment, the method comprises contacting a cell
with an effective amount of cotinine, or a physiologically acceptable
salt thereof In one embodiment, the cell is a neuron. In a specific
embodiment, the cell is a cortical cell.
[0046] The subject invention concerns materials and methods for detecting,
diagnosing, and/or monitoring conditions associated with accumulation
and/or aggregation of A.beta. peptide in neural tissue, such as
Alzheimer's disease and Parkinson's disease. In one embodiment, a method
of the invention comprises administering detectably labeled cotinine to a
person or animal. The method of the invention optionally comprises
labeling cotinine with a detectable label. The cotinine can be
administered through any suitable route, e.g., intravenously. The labeled
cotinine is then detected, e.g., via radioimaging. The level or
concentration and/or location of labeled cotinine in neural tissue can be
determined and/or analyzed and a diagnosis made. In one embodiment, the
cotinine is labeled with a radioisotope that can be detected by Positron
Emission Tomography (PET). PET detectable radioisotopes include, for
example, carbon-11, nitrogen-13, oxygen-15, fluorine-18, bromine-76, and
iodine-121. In another embodiment, cotinine is labeled with a
radioisotope that can be detected using single photon emission computed
tomography (SPECT). SPECT detectable radioisotopes include, for example,
99m-Technetium, 123-iodine, and 111-indium. PET and SPECT techniques
using compounds other than cotinine are known in the art and can be
applied to the use of cotinine in practicing the present invention.
Methods of the invention using labeled cotinine can also be practiced in
conjunction with other imaging agents such as Pittsburgh Compound B (PIB)
and "C-BF-227" (Kudo et al., 2007). Methods of the invention can also be
used in conjunction with other imaging systems such as computed
tomography (CT) and magnetic resonance imaging (MRI) for detecting and/or
diagnosing conditions associated with A.beta. peptide. In one embodiment,
Parkinson's disease can be diagnosed by detection of cotinine in
striatum.
[0047] Radiolabeled cotinine of the invention can be administered at any
suitable dose as determined for a particular application by an ordinarily
skilled clinician. In one embodiment, radiolabeled cotinine may be
administered at a dose of about 1 to 100 mCi per 70 kg of body weight.
The radiolabeled cotinine can be administered, for example, in a
physiologically acceptable solution, such as a physiologically acceptable
saline solution.
[0048] The subject invention also concerns methods for identifying and
evaluating the efficacy of drugs for treatment of disease associated with
A.beta. accumulation and/or aggregation. The levels, location, and/or
changes in A.beta. peptide accumulation and/or aggregation in a tissue
can be determined before, during, and after the treatment regimen. In one
embodiment, the level, location and/or changes of A.beta. accumulation in
neural tissue (as indicated by the presence of labeled cotinine) in a
subject is determined using a method of the invention. The subject is
then treated with the drug or therapeutic of interest. The level and/or
location of Abeta during and/or after treatment is monitored and analyzed
using a method of the invention. The efficacy of the drug can be
evaluated by monitoring and analyzing Abeta changes in the subject's
neural tissue as a result of the treatment.
[0049] Specific Embodiments Include:
[0050] A. A method for identifying and evaluating the efficacy of a drug
or therapeutic for treatment of a disease or condition associated with
A.beta. accumulation and/or aggregation in a neural tissue, wherein said
method comprises i) administering detectably labeled cotinine, or an
isomer or racemate thereof, to a person or animal to determine the level
or concentration and/or location of A.beta. accumulation and/or
aggregation in said tissue; ii) treating the person or animal with said
drug or therapeutic; iii) monitoring and/or analyzing changes in the
level or concentration and/or location of A.beta. accumulation and/or
aggregation in said tissue following said drug or therapeutic treatment.
[0051] B. The method according to embodiment A, wherein said labeled
cotinine is detected using radioimaging.
[0052] C. The method according to embodiment A, wherein the level or
concentration and/or location in neural tissue of said labeled cotinine
is determined and/or analyzed.
[0053] D. The method according to embodiment A, wherein said labeled
cotinine is labeled with a radioisotope.
[0054] E. The method according to embodiment D, wherein said radioisotope
is detectable by Position Emission Tomography (PET) and/or single photon
emission computed tomography (SPECT).
[0055] F. The method according to embodiment E, wherein said radioisotope
is carbon-11, nitrogen-13, oxygen-15, fluorine-18, bromine-76,
iodine-121, technetium-99m, iodine-123, or indium-111.
[0056] G. The method according to embodiment A, wherein said method
further comprises administering one or more imaging agents.
[0057] H. The method according to embodiment G, wherein said imaging agent
is Pittsburgh Compound B (PIB) or "C-BF-227".
[0058] I. The method according to embodiment A, wherein the condition is
Parkinson's disease or Alzheimer's disease.
[0059] J. The method according to embodiment A, wherein detection of said
labeled cotinine in striatum is indicative of Parkinson's disease.
[0060] K. The method according to embodiment A, wherein said labeled
cotinine is radiolabeled and administered at a dose of about 1 mCi per 70
kg of body weight to about 100 mCi per 70 kg of body weight.
[0061] L. The method according to embodiment A, wherein said labeled
cotinine is administered in a physiologically acceptable carrier, buffer,
or diluent.
[0062] The subject invention also concerns a detectably labeled cotinine
molecule. In one embodiment, the cotinine is radiolabeled. In a specific
embodiment, the cotinine is labeled with a radioisotope suitable for PET
or SPECT detection. PET detectable radioisotopes include, for example,
carbon-11, nitrogen-13, oxygen-15, fluorine-18, bromine-76, and
iodine-121. SPECT detectable radioisotopes include, for example,
99m-Technetium, 123-iodine, and 111-indium. The labeled cotinine can be
provided in a physiologically acceptable carrier, buffer, or diluent.
[0063] The subject invention also concerns kits comprising in one or more
containers: cotinine or a composition comprising cotinine, or a
pharmaceutically acceptable salt and/or analog thereof, and optionally
one or more compounds used to treat or prevent neurodegenerative
conditions or stress disorders. In one embodiment, a kit of the invention
comprises one or more of donepezil, galantamine, vivastigmine, memantine,
or selegiline. In another embodiment, a kit comprises one or more of
monoamine oxidase (MAO) inhibitors; antiepileptic drugs; selective
serotonin reuptake inhibitors (SSRI), such as citalopram, escitalopram,
fluvoxamine, paroxetine, sertraline, rasagiline, selegiline, L-dopa,
carbidopa, and benserazide, or an isomer or analog thereof;
serotonin-norepinephrine reuptake inhibitors (SNRI), such as venlafaxine,
desvenlafaxine, duloxetine, sibutramine, and milnacipran; tricyclic
antidepressants (TCAs); 3,4-methylenedioxy-N-methylamphetamine (MDMA);
propranolol; clonidine, and ziprasidone, or an isomer or analog thereof
Kits of the invention can optionally include pharmaceutically acceptable
carriers and/or diluents. In one embodiment, a kit of the invention
comprises cotinine labeled with a detectable label, or composition
comprising the labeled cotinine. In one embodiment, the cotinine is
labeled with a radioisotope that can be detected by Positron Emission
Tomography (PET). PET detectable radioisotopes include, for example,
carbon-11, nitrogen-13, oxygen-15, fluorine-18, bromine-76, and
iodine-121. In another embodiment, cotinine is labeled with a
radioisotope that can be detected using single photon emission computed
tomography (SPECT). SPECT detectable radioisotopes include, for example,
99 m-Technetium, 123-iodine, and 111-indium. In one embodiment, a kit of
the invention includes one or more other components, adjuncts, or
adjuvants as described herein. In one embodiment, a kit of the invention
includes instructions or packaging materials that describe how to
administer and/or how to use a compound or composition of the kit for the
treatment of a stress disorder,
[0064] Down's syndrome, or a neurodegenerative condition, or for
detection, diagnosis, and/or monitoring a condition associated with Al3
peptide accumulation and/or aggregation in a tissue. Containers of the
kit can be of any suitable material, e.g., glass, plastic, metal, etc.,
and of any suitable size, shape, or configuration. In one embodiment, a
compound of the invention is provided in the kit as a solid, such as a
tablet, pill, chewing gum, or powder form. In another embodiment, a
compound of the invention is provided in the kit as a liquid or solution.
In one embodiment, the kit comprises an ampoule or syringe containing a
compound of the invention in liquid or solution form.
[0065] Specific Embodiments Include:
[0066] A. A kit comprising in one or more containers:
[0067] i) a cotinine molecule, or a composition comprising said cotinine
molecule; and optionally
[0068] ii) one or more other drugs useful in treating a neurodegenerative
disorder, Down's syndrome, or a stress disorder.
[0069] B. The kit according to embodiment A, wherein said kit comprises
donepezil
[0070] (ARICEPT), galantamine (RAZADYNE), rivastigmine (EXELON), memantine
(AKATINOL), selegiline (ELDEPRYL), a selective serotonin reuptake
inhibitor (SSRI), a serotonin-norepinephrine reuptake inhibitor (SNRI), a
tricyclic antidepressant (TCA), 3,4-methylenedioxy-N-methylamphetamine
(MDMA), propranolol, clonidine, or ziprasidone, or an isomer or analog
thereof, or a pharmaceutically acceptable salt thereof.
[0071] C. The kit according to embodiment A, further comprising
instructions and/or packaging materials that describe how to use and/or
administer a cotinine molecule or composition of the kit for treating a
neurodegenerative disorder, Down's syndrome, or a stress disorder.
[0072] D. The kit according to embodiment A, wherein the cotinine molecule
is labeled with a detectable label.
[0073] E. The kit according to embodiment A, further comprising a
pharmaceutically acceptable carrier and/or diluent.
[0074] To provide for the administration of dosages for the desired
therapeutic treatment, in some embodiments, pharmaceutical compositions
of the invention can comprise between about 0.1% and 45%, and especially,
1 and 15%, by weight of the total of one or more of the compounds based
on the weight of the total composition including carrier or diluents.
Illustratively, dosage levels of the administered active ingredients can
be: intravenous, 0.01 to about 20 mg/kg; intraperitoneal, 0.01 to about
100 mg/kg; subcutaneous, 0.01 to about 100 mg/kg; intramuscular, 0.01 to
about 100 mg/kg; orally 0.01 to about 200 mg/kg, and preferably about 1
to 100 mg/kg; intranasal instillation, 0.01 to about 20 mg/kg; and
aerosol, 0.01 to about 20 mg/kg of animal (body) weight.
[0075] The compounds of the present invention include all hydrates and
salts that can be prepared by those of skill in the art. Under conditions
where the compounds of the present invention are sufficiently basic or
acidic to form stable nontoxic acid or base salts, administration of the
compounds as salts may be appropriate. Examples of pharmaceutically
acceptable salts are organic acid addition salts formed with acids that
form a physiological acceptable anion, for example, tosylate,
methanesulfonate, acetate, citrate, malonate, tartarate, succinate,
benzoate, ascorbate, alpha-ketoglutarate, and alpha-glycerophosphate.
Suitable inorganic salts may also be formed, including hydrochloride,
sulfate, nitrate, bicarbonate, and carbonate salts.
[0076] It will be appreciated by those skilled in the art that certain of
the compounds of the invention may contain one or more asymmetrically
substituted carbon atoms which can give rise to stereoisomers. It is
understood that the invention extends to all such stereoisomers,
including enantiomers, and diastereoisomers and mixtures, including
racemic mixtures thereof.
[0077] In vivo application of the subject compounds, and compositions
containing them, can be accomplished by any suitable method and technique
presently or prospectively known to those skilled in the art. The subject
compounds can be formulated in a physiologically- or
pharmaceutically-acceptable form and administered by any suitable route
known in the art including, for example, oral, nasal, rectal, and
parenteral routes of administration. As used herein, the term parenteral
includes subcutaneous, intradermal, intravenous, intramuscular,
intraperitoneal, and intrasternal administration, such as by injection.
Administration of the subject compounds of the invention can be a single
administration, or at continuous or distinct intervals as can be readily
determined by a person skilled in the art.
[0078] The compounds of the subject invention, and compositions comprising
them, can also be administered utilizing liposome technology, slow
release capsules, implantable pumps, and biodegradable containers. These
delivery methods can, advantageously, provide a uniform dosage over an
extended period of time. The compounds of the invention can also be
administered in their salt derivative forms or crystalline forms.
[0079] Compounds of the subject invention can be formulated according to
known methods for preparing physiologically acceptable compositions.
Formulations are described in detail in a number of sources which are
well known and readily available to those skilled in the art. For
example, Remington's Pharmaceutical Science by E. W. Martin describes
formulations which can be used in connection with the subject invention.
In general, the compositions of the subject invention will be formulated
such that an effective amount of the compound is combined with a suitable
carrier in order to facilitate effective administration of the
composition. The compositions used in the present methods can also be in
a variety of forms. These include, for example, solid, semi-solid, and
liquid dosage forms, such as tablets, pills, powders, liquid solutions or
suspension, suppositories, injectable and infusible solutions, and
sprays. The preferred form depends on the intended mode of administration
and therapeutic application. The compositions also preferably include
conventional physiologically-acceptable carriers and diluents which are
known to those skilled in the art. Examples of carriers or diluents for
use with the subject compounds include ethanol, dimethyl sulfoxide,
glycerol, alumina, starch, saline, and equivalent carriers and diluents.
To provide for the administration of such dosages for the desired
therapeutic treatment, compositions of the invention will advantageously
comprise between about 0.1% and 99%, and especially, 1 and 15% by weight
of the total of one or more of the subject compounds based on the weight
of the total composition including carrier or diluent.
[0080] Compounds of the invention, and compositions thereof, may be
systemically administered, such as intravenously or orally, optionally in
combination with a pharmaceutically acceptable carrier such as an inert
diluent, or an assimilable edible carrier for oral delivery. They may be
enclosed in hard or soft shell gelatin capsules, may be compressed into
tablets, or may be incorporated directly with the food of the patient's
diet. For oral therapeutic administration, the active compound may be
combined with one or more excipients and used in the form of ingestible
tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups,
wafers, aerosol sprays, and the like.
[0081] The tablets, troches, pills, capsules, and the like may also
contain the following: binders such as gum tragacanth, acacia, corn
starch or gelatin; excipients such as dicalcium phosphate; a
disintegrating agent such as corn starch, potato starch, alginic acid and
the like; a lubricant such as magnesium stearate; and a sweetening agent
such as sucrose, fructose, lactose or aspartame or a flavoring agent such
as peppermint, oil of wintergreen, or cherry flavoring may be added. When
the unit dosage form is a capsule, it may contain, in addition to
materials of the above type, a liquid carrier, such as a vegetable oil or
a polyethylene glycol. Various other materials may be present as coatings
or to otherwise modify the physical form of the solid unit dosage form.
For instance, tablets, pills, or capsules may be coated with gelatin,
wax, shellac, or sugar and the like. A syrup or elixir may contain the
active compound, sucrose or fructose as a sweetening agent, methyl and
propylparabens as preservatives, a dye and flavoring such as cherry or
orange flavor. Of course, any material used in preparing any unit dosage
form should be pharmaceutically acceptable and substantially non-toxic in
the amounts employed. In addition, the active compound may be
incorporated into sustained-release preparations and devices.
[0082] Compounds and compositions of the invention, including
pharmaceutically acceptable salts or analogs thereof, can be administered
intravenously, intramuscularly, or intraperitoneally by infusion or
injection. Solutions of the active agent or its salts can be prepared in
water, optionally mixed with a nontoxic surfactant. Dispersions can also
be prepared in glycerol, liquid polyethylene glycols, triacetin, and
mixtures thereof and in oils. Under ordinary conditions of storage and
use, these preparations can contain a preservative to prevent the growth
of microorganisms.
[0083] The pharmaceutical dosage forms suitable for injection or infusion
can include sterile aqueous solutions or dispersions or sterile powders
comprising the active ingredient which are adapted for the extemporaneous
preparation of sterile injectable or infusible solutions or dispersions,
optionally encapsulated in liposomes. The ultimate dosage form should be
sterile, fluid and stable under the conditions of manufacture and
storage. The liquid carrier or vehicle can be a solvent or liquid
dispersion medium comprising, for example, water, ethanol, a polyol (for
example, glycerol, propylene glycol, liquid polyethylene glycols, and the
like), vegetable oils, nontoxic glyceryl esters, and suitable mixtures
thereof. The proper fluidity can be maintained, for example, by the
formation of liposomes, by the maintenance of the required particle size
in the case of dispersions or by the use of surfactants. Optionally, the
prevention of the action of microorganisms can be brought about by
various other antibacterial and antifungal agents, for example, parabens,
chlorobutanol, phenol, sorbic acid, thimerosal, and the like. In many
cases, it will be preferable to include isotonic agents, for example,
sugars, buffers or sodium chloride. Prolonged absorption of the
injectable compositions can be brought about by the inclusion of agents
that delay absorption, for example, aluminum monostearate and gelatin.
[0084] Sterile injectable solutions are prepared by incorporating a
compound of the invention in the required amount in the appropriate
solvent with various other ingredients enumerated above, as required,
followed by filter sterilization. In the case of sterile powders for the
preparation of sterile injectable solutions, the preferred methods of
preparation are vacuum drying and the freeze drying techniques, which
yield a powder of the active ingredient plus any additional desired
ingredient present in the previously sterile-filtered solutions.
[0085] Useful dosages of the compounds and pharmaceutical compositions of
the present invention can be determined by comparing their in vitro
activity, and in vivo activity in animal models. Methods for the
extrapolation of effective dosages in mice, and other animals, to humans
are known to the art; for example, see U.S. Pat. No. 4,938,949.
[0086] The dose administered to a patient, particularly a human, in the
context of the present invention should be sufficient to achieve a
therapeutic response in the patient over a reasonable time frame, without
lethal toxicity, and preferably causing no more than an acceptable level
of side effects or morbidity. One skilled in the art will recognize that
dosage will depend upon a variety of factors including the condition
(health) of the subject, the body weight of the subject, kind of
concurrent treatment, if any, frequency of treatment, therapeutic ratio,
as well as the severity and stage of the pathological condition.
[0087] Mammalian species that benefit from the disclosed methods include,
but are not limited to, primates, such as apes, chimpanzees, orangutans,
humans, monkeys; domesticated animals (e.g., pets) such as dogs, cats,
guinea pigs, hamsters, Vietnamese pot-bellied pigs, rabbits, and ferrets;
domesticated farm animals such as cows, buffalo bison, horses, donkey,
swine, sheep, and goats; exotic animals typically found in zoos such as
bear, lions, tigers, panthers, elephants, hippopotamus, rhinoceros,
giraffes antelopes, sloth, gazelles, zebras, wildebeests, prairie dogs,
koala bears, kangaroo opossums, raccoons, pandas, hyena, seals, sea
lions, elephant seals, otters, porpoises dolphins, and whales. As used
herein, the terms "subject" "host", and "patient" are used
interchangeably and intended to include such human and non-human
mammalian species.
[0088] The effect of cotinine on A.beta. toxicity in cultured cortical
neurons has been determined. After 7 days in vitro cells were treated
with 5 .mu.M A.beta. alone or in the presence of cotinine for 24 hours.
After this time cell survival was assessed by MTT and PI/Calcein-AM
assays. The results showed that cotinine protected neurons against
A.beta. toxicity and increased cell survival from 76% (A.beta. alone) to
85% (A.beta.+10 .mu.M cotinine) of vehicle-treated control cells as
assessed using MTT assay. Similar results were obtained using PI and
calcein-AM dyes. To determine whether the neuroprotection by cotinine
involved the activity of the nAChRs, the effect of cotinine on A.beta.
toxicity was studied on cortical cells pre-treated with 10 nM .alpha.-Bgt
and mecamylamine.
[0089] The results showed that .alpha.-Bgt was able to reverse the
beneficial actions of nicotine against A.beta. toxicity but not those of
cotinine. We then investigated whether cotinine affected A.beta.
oligomerization by pre-incubating A.beta. plus cotinine together, and
then performing the toxicity assay and investigating the presence of
A.beta. oligomers by dot blot. The results suggest that cotinine protects
cortical cells against A.beta. toxicity by inhibiting A.beta.
oligomerization and by a mechanism that does not involve cotinine as an
agonist of the nAChRs.
[0090] All patents, patent applications, provisional applications, and
publications referred to or cited herein are incorporated by reference in
their entirety, including all figures and tables, to the extent they are
not inconsistent with the explicit teachings of this specification.
[0091] Following are examples that illustrate procedures for practicing
the invention. These examples should not be construed as limiting. All
percentages are by weight and all solvent mixture proportions are by
volume unless otherwise noted.
Materials and Methods for Examples 1-7
[0092] Western Blot. Cell protein extracts were separated by
SDS-PAGE4-20%, transferred to nitrocellulose membranes, blocked with 5%
skim milk in PBS-Tween 0.05%, and incubated with polyclonal antibodies
against pCREB, (3-tubulin, and GADPH overnight and after washing
incubated with appropriate secondary antibodies for 1-2 hours.
Immunoreactive bands were visualized using ECL.
[0093] A.beta. toxicity assay. Primary cortical embryonic rat neurons were
incubated with 5 .mu.M A.beta. in the presence or absence of various
concentrations cotinine for 4 hours as described (Echeverria et al.
(2005)). Cell viability was assessed using the MTT assay (Sigma). As an
alternative approach cell viability after exposure to A.beta. and
cotinine was assessed using the vital dye calcein-AM (green fluorescence)
to stain live cells and propidium iodide to stain dead cells. MTT values
were normalized to control values considered 100%.
[0094] Dot Blot. The dot blot analysis was performed as described (Necula
et al. (2007)). 3 .mu.l of the oligomerization mix were applied onto
nitrocellulose membranes and left to dry. After drying, the membranes
were blocked for 1 hour at room temperature with 10% skim milk in TBS
containing 0.05% Tween20 (TBS-T). The membranes were washed and incubated
with the A.beta. 6E10 (1 mg/ml) diluted in TBS-T containing 5% milk
overnight at room temperature. After washing with TBS-T membranes were
incubated with horseradish peroxidase-conjugated secondary antibody
(1:5000) for 1 hour and analyzed using ECL.
Example 1
The Survival of Cortical Neurons is not Affected by Cotinine
[0095] Cortical cells were subjected to various concentrations of cotinine
and cell viability was assessed after 48 hours by MTT assay (see FIG. 1).
Statistical significance of the differences in MTT values was assessed by
one-way ANOVA with Tukey post-test. ns, not significant difference with
(P>0.05).
Example 2
Cotinine Protects Neurons Against A.beta. Toxicity
[0096] After 7 days in vitro, cortical neurons were treated with 5 .mu.M
A.beta., either alone or with various concentrations of cotinine (0.1, 1,
10 .mu.M). After 24 hours cell viability was assessed using MTT assay
(FIG. 2A) and double calcein-AM and PI staining (FIG. 2B). MTT values
were normalized against control values considered 100%. The calcein-AM
and PI staining was performed in the cortical cells subjected to A.beta.
toxicity for 24 hours. After 30 minutes, stained cells were analyzed by
fluorescence microscopy. Scalebar=20 .mu.m. The values represent the
mean.+-.S.E.M., with significant difference with P<0.05, *(P<0.05),
**(P<0.01), ***(P<0.001), between vehicle mean and treated samples
mean.
Example 3
Cotinine is Neuroprotective by Blocking A.beta. Oligomerization
[0097] After 7 days in vitro, cortical cells were treated with an
A.beta..sub.1-42 solution pre-incubated for 3 hours at 4.degree. C.
before being added to the culture media containing 10 .mu.M cotinine.
After 24 hours of treatment cell viability was assessed using MTT assay.
In FIG. 3A, different solutions of 5 .mu.M A.beta. peptide or A.beta.
plus cotinine, was added to the culture media after a pre-incubation step
in PBS in the presence or absence of different concentrations of cotinine
for 3 hours. After 24 hours of treatment, cortical cell viability was
assessed using MTT assay. In FIG. 3B, the 20.times. A.beta. solution was
prepared by pre-incubating 200 .mu.M A.beta. solution in PBS for 3 hours
at 4.degree. C. in the presence or absence of ascending concentrations of
cotinine (50, 100, 200, 500 .mu.M), when the solutions were added they
were diluted to the concentrations indicated. The histograms represent
the cell viability as percentage of vehicle-treated controls. The results
were considered not significant, ns with P>0.05, significant with
P<0.05(*), and highly significant P<0.01(***) as evaluated using
One-way ANOVA with turkey post test.
Example 4
Cotinine is not an Agonist of the nAChRs
[0098] 7 days in vitro, cortical neurons were pretreated or not with the
.alpha.-7 nAChR antagonist .alpha.-Bgt (10 nM) and then treated with
A.beta. (5 .mu.M), alone and/or with various concentrations of cotinine
(0.1, 1 and 10 .mu.M). After 24 hours cell viability was assessed using
MTT assay (FIG. 4A). Cortical neurons after 7 days in vitro were treated
with the nonselective nAChR antagonist (1 .mu.M) alone or in the presence
of cotinine (10 mM). After 24 hours, cell viability was assessed using
MTT assay (FIG. 4B). MTT values represent the mean.+-.S.E.M., with
significant difference with P<0.05, *(P<0.05), *** (P<0.001),
between vehicle mean and treated samples mean.
Example 5
Cotinine Inhibits A.beta. Oligomerization
[0099] Aliquots of an A.beta. oligomerization mix were analyzed using the
A.beta. antibody 6e10 by Dot Blot after 3 days of incubation at room
temperature. Briefly, A.beta. (50 .mu.M) was subjected to oligomerization
conditions in the presence or absence of cotinine (50, 100, 200, 500
.mu.M) and aliquots were analyzed using the A.beta. antibody 6E10 as
described in "Materials and Methods". The results are shown in FIG. 5.
Example 6
Cotinine Restores the BDNF-Stimulated Phosphorylation of CREB in Cortical
Cells
[0100] Western blot analysis of the BDNF-stimulated phosphorylation of
CREB in extracts of cortical cells. Cells were exposed to vehicle, 5
.mu.M A.beta. alone or 5 .mu.M A.beta. plus 10 .mu.M cotinine for 5
hours, then to BDNF (50 ng/ml) for 1 hour and analyzed for CREB by
western blot (FIG. 6B). The histogram (FIG. 6A) represents the levels of
phospho-CREB (Ser133) normalized against .beta.-Tubulin used as a control
of protein loading. The values represent significant (*) difference with
P<0.05.
Example 7
[0101] It has been discovered that cotinine protects brain cortical cells
against the toxicity of the Amyloid beta peptide. The cortical cells were
exposed to 5 microM A.beta. for 24 hours and 48 hours and analyzed for
cell viability using two viability tests. Cell viability was quantified
by MTT and propidium iodide (PI) and calcein-AM staining assays. MTT
assay measures the mitochondrial conversion of the tetrazolium salt MTT
(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) to
formazan. To perform the MTT assay the cell culture medium was replaced
with medium containing MTT (0.5 mg/mL). Following 1-4 h of incubation at
37.degree. C., MTT formazan crystals were dissolved in DMSO and
absorbance at 570 nm was measured. Absorbance values are a measure of
cell viability. MTT results are expressed as percentage of vehicle
treated controls. MTT assays were performed by measuring the levels of
formazan after dissolving the precipitates in DMSO. The double calcein-AM
and PI staining, involves staining with PI (a fluorescent nucleic acid
dye used for the staining of dead cells) and calcein-AM a compound that
inside of live brain cells, is converted to the green fluorescent
compound calcein. After 30 minutes of incubation of the cells with these
compounds were washed and analyzed by fluorescence microscopy. The
results show that cotinine protects neurons against the toxicity of
A.beta. peptide, a peptide that accumulates in the brain of AD patients,
and is neurotoxic. Cotinine inhibits Abeta oligomerization and prevents
its toxicity on cortical neurons.
[0102] The neuroprotective actions of cotinine are independent of the
nicotininc Acetylcholine receptors (nAChR) as it was not affected by
alpha-Bungarotoxin, or mecamylamine nAChRs antagonists.
[0103] Cotinine can also be beneficial against post-traumatic stress
disorders, as we discovered that cotinine increases the activity of
DARPP-32 in neurons from rat brain cells. DARPP-32 stimulates cAMP
signaling a molecular mechanism that favors the brain plasticity that is
required to "forget" traumatic memories that increase anxiety and
psychological suffering in post-traumatic stress disorders. Cotinine also
facilitates serotonin release and prevent psychosis related behavioral
abnormalities in rats. Thus, cotinine can be useful in treating PTSD
patients and can act as a serotonin reuptake inhibitor in addition to its
neuroprotective actions.
Materials and Methods for Examples 8-13
[0104] Drugs. Cotinine was purchased from Sigma Chemical Company (Saint
Louis, Mo., USA).
[0105] Cortical cells. Embryonic rat cortical neurons were cultured
following the protocol described (Brewer (1995)) but using embryonic
cortical tissues obtained from Brain Bits LLC (Springfield, Ill., USA).
The brain tissues were dissociated by 0.05% (v/v) trypsin digestion and
dissociated by repeated passages through a pipette tip. Cortical cells
(2.times.10.sup.5 cells, 1,250 cells/mm.sup.2) were plated in Neurobasal
E medium, supplemented with 2% B27, and 1 mM Glutamax and plated onto
20-mm tissue culture wells coated with poly-D-lysine (0.1 mg/ml). Then
cortical cells were incubated at 37.degree. C. in a humidified incubator
with 95% air/5% CO.sub.2 for 7-10 days, before being used for cell
viability and protein expression analysis.
[0106] Preparation of A.beta. oligomers. A.beta..sub.1-42 peptide was
obtained from American Peptide (Sunnyvale, Calif., USA). To obtain
A.beta..sub.1-42 oligomer solutions, we used a previously described
protocol that results in solutions containing stable oligomers, but not
fibrils for several days (Necula et al. (2007)). The lyophilized peptide
was dissolved in 1 volume of 1 mM NaOH and then diluted in
phosphate-buffered saline (PBS) pH 7.4 to the desired concentrations.
[0107] A.beta. toxicity assay. For the A.beta. neurotoxicity assay, after
7 days in vitro (DIV) the conditioned media of cortical cells was
replaced with Neurobasal E medium, supplemented with 2% B27 without
antioxidants (B27-AO; Invitrogen, Carlsbad, Calif.) for 2 h. Cells were
then exposed to freshly prepared A.beta..sub.1-42 solution in the
presence or absence of various concentrations of cotinine.
[0108] Cell viability assays. Cell viability was quantified by MTT and
propidium iodide (PI) and calcein-AM staining. MTT assay measures the
viability of cells by analyzing the mitochondrial conversion of the
tetrazolium salt MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl
tetrazolium bromide) to formazan. To perform the MTT assay, the cell
culture medium was replaced with Neurobasal medium containing
freshly-dissolved MTT (0.5 mg/mL). Following 1-4 h incubation at
37.degree. C., MTT formazan crystals were dissolved in DMSO and
absorbance at 590 nm was measured. MTT results are expressed as a
percentage of vehicle-treated controls.
[0109] In the double calcein-AM and Propidium iodide (PI) staining, PI
binds to nucleic acid and is commonly used for identifying dead cells,
since it is impermeable to the membranes of viable cells. Calcein-AM is
converted to calcein by live cells, binds to the cellular calcium, and
stains the cells by emitting a green fluorescence. The cortical cells
were subjected to A.beta. toxicity for 24 h and then 2 .mu.M calcein-AM
and 1 .mu.M PI were added to the conditioned media and incubated for 30
min. After incubation cells were washed with PBS and the number of
calcein-stained (green) and nuclei stained with PI (red) were analyzed by
fluorescence microscopy. More than 600 cells per condition were analyzed
in several 20.times. focal planes and recorded.
[0110] Western blot analysis of cell extracts. Rat embryonic cortical
cells were cultured in 24-well plates (0.3.times.10.sup.6 cells/well) for
7 days, washed with PBS, collected and disrupted by sonication in
ice-cold cell lysis buffer containing (20 mM Tris (pH 7.4), 150 mM NaCl,
1 mM ethylenediaminetetraacetic acid (EDTA), 1 mM egtazic acid (EGTA), 1%
triton, 2.5 mM Na pyrophosphate, 1 mM .beta.-glycerophosphate, 1 mM Na
orthovanadate, 1 .mu.g/ml leupeptin) (Cell Signaling Technology, Beverly,
Mass., USA), 1 mM phenylmethylsulfonyl fluoride (PMSF) (Sigma) complete
protease inhibitor cocktail (Roche Molecular Biochemicals, Indianapolis,
Ind., USA). After sonication, cell extracts were incubated on ice for 30
min and centrifuged at 20,000 g for 30 min at 4.degree. C. Protein
concentration of supernatants was measured by Bio-Rad protein assay
(Bio-Rad, Hercules, Calif., USA), and equal amounts of protein were
separated by gradient (4-20%) SDS-PAGE and transferred to nitrocellulose
membranes (BA83 0.2 .mu.m; Bio-Rad). The membranes were blocked in
Tris-buffered saline with 0.1% Tween 20 (TTBS) containing 10% dry skim
milk for 45 min. Membranes were incubated with primary antibodies in TTBS
with 3% dry milk overnight at 4.degree. C. and with secondary antibodies
for 1 h. A rabbit polyclonal antibody directed against phospho-CREB
kinases (Serine 133) was used (Cell Signaling). A monoclonal mouse
antibody directed against .beta.-tubulin (Promega, Madison, Wis., USA)
was used to control protein sample loading and transfer efficiency. The
immunoreactive bands were visualized using Dura ECL detection kit (ECL,
Pharmacia Biotech, Piscataway, N.J., USA), the Kodak Image Station 440CF
and analyzed using the molecular Imaging Software, version 4.0
(Rochester, N.Y., USA) and NIH ImageJ software.
[0111] Analysis of cotinine on oligomerization/aggregation of A.beta.. For
the analysis of the inhibition of A.beta..sub.1-42
oligomerization/aggregation reaction, we incubated A.beta. (100 .mu.M, pH
7.4) prepared in the absence or presence of ascending concentrations of
cotinine (100, 200 and 500 .mu.M) for 7 days at 25.degree. C. and
analyzed on days 2, 5, 6 and 7. A.beta. oligomerization was analyzed by
Western blot and dot-blot immunoassays using antibody 6E10, which
preferentially recognizes the monomeric form of A.beta. and the A11
antibody that specifically recognizes the oligomeric form of the peptide
but not A.beta. monomers, protofibrils or fibrils.
[0112] Western blot analysis of A.beta.. The western blot analysis was
performed as described before (Necula et al. (2007)). 10 .mu.l-aliquots
of each oligomerization reaction containing A.beta. alone or A.beta. plus
cotinine were mixed with 5.times.SDS sample buffer and loaded in a 4-20%
Tris-HCl gel and analyzed by Western blot using the 6E10 antibody.
[0113] Dot-blot immunoassays. The dot-blot analysis was performed as
described (Necula et al. (2007)). 4-8 .mu.l of the oligomerization
mixture was applied onto nitrocellulose membranes and allowed to dry,
after which the membranes were blocked for 1 h at room temperature with
10% skim milk in TBS containing 0.05% Tween 20 (TBS-T). The membranes
were then washed and incubated with 6E10 antibody (1:20,000) diluted in
TBS-T containing 5% milk overnight at 4.degree. C. After being washed
with TBS-T, membranes were incubated with horseradish
peroxidase-conjugated secondary antibody (1:5000) for 1 h, and visualized
using enhanced chemiluminescence (Dura ECL detection kit, Pharmacia
Biotech, Piscataway, N.J., USA), scanned on the Kodak Image Station
440CF, and analyzed using Molecular Imaging Software version 4.0
(Rochester, N.Y., USA) and NIH ImageJ software. The A.beta. solutions for
each particular day were analyzed in the same membrane and developed
simultaneously.
[0114] Peptides and preparation of diffraction samples. Solutions of
A.beta..sub.1-42 were prepared by dissolving the peptide in 1 mM NaOH.
Then, sufficient PBS pH 7.4 was added to make A.beta..sub.1-42 solutions
at 200 .mu.M. These solutions were further diluted with PBS alone or PBS
plus cotinine to obtain solutions with a final concentration of 100 .mu.M
A.beta. and ascending concentrations of cotinine. After preparation the
solutions were immediately lyophilized or incubated at room temperature
(25.degree. C.) for 3 days before lyophilization. The lyophilized samples
were placed in siliconized 0.7 mm-diameter, thin-walled glass capillary
tubes and kept at room temperature (RT). After x-ray diffraction the
lyophilized samples were vapor-hydrated and re-examined by diffraction.
The x-ray diffraction measurements were undertaken as previously detailed
(Kirschner et al. (2008)).
[0115] Atomic Force Microscopy Analysis.
[0116] a) Formation of A.beta. aggregates: Since the aggregation behavior
of A.beta. is dependent on the presence of small concentrations of
aggregated forms of the peptide, that are present in many commercial
samples, we prepared the A.beta. solution by first dissolving the peptide
in Hexafluoroisopropanol (HFIP), a protocol that produces a starting
solution constituted only of A.beta. monomers (Chromy et al. (2003)).
Lyophillized A.beta..sub.1-42 (American peptide) (1 mg) was dissolved in
HFIP, evaporated and re-dissolved in 22 .mu.l of dimethyl sulfoxide
(DMSO, St. Louis, Mo.). These peptide preparations were then diluted in
PBS buffer pH 7.4 alone or PBS plus cotinine to obtain solutions
containing 1 mM A.beta..sub.1-42 with and without 2 mM cotinine. Then the
A.beta..sub.1-42 solutions were incubated for 10 days and the formation
of oligomers and fibers was examined.
[0117] b) Preparation of samples: 20 .mu.l aliquots of A.beta. solutions
were deposited on freshly cleaned and dried silicon wafers (approximately
1 mm thick). After waiting for 10 mM, non-adsorbed portions of the
samples were washed with de-ionized water (2000 .mu.l). The wet surface
of the silicon wafer was then dried using gentle flow of air.
[0118] c) AFM analysis: The AFM analysis was performed using an AFM
apparatus (AFM, .beta.A multimode SPM, Model no. 920-006-101, Vecco) that
permits the acquisition of images using a tapping mode approach. This
approach allows intermittent contact of the tip with the sample and
minimizes the chances of deformation of the peptide samples. The
cantilever and the tip were =made up of silicon and the cantilever force
constant was approximately 20-100 N/m with the resonance frequency
between 200-400 khz. The scan rate was between 1.0 to 1.2 Hz. The
analysis of fibrils and oligomers was performed using the software
NanoScope Control, version 5.30.
[0119] Molecular modeling. The molecular modeling of the interaction
between cotinine and the A.beta..sub.1-42 monomer was performed in the
following two steps.
[0120] a) Molecular Docking: In this step, cotinine was docked near the
His13 and His14 residues containing site of the full-length
A.beta..sub.1-42 peptide using the AutoDock program (version 4.0) (Morris
et al. (1998)). The most representative structure obtained from our
previous 50 ns MD simulations on full-length A.beta..sub.1-42 in aqueous
solution was used in the docking procedure (Triguero et al. (2008)). The
reported binding sites of nicotine on A.beta..sub.1-42 were utilized in
this process (Salomon et al. (1996); Moore et al. (2004); Ono et al.
(2002)). The AutoDock program performed the rapid energy evaluation
through a pre-calculated grid and found the suitable binding position of
cotinine on A.beta..sub.1-42. Polar hydrogens were added using the
hydrogen module in the AutoDock tools (ADT) for the peptide and the
Kollman united atom partial charges were assigned. The grid was
calculated using the Auto Grid protocol. It was chosen to include all the
His residues (His6, His13 and His14) of A.beta..sub.1-42. The dimension
of the grid was set to 50.times.50.times.50 .ANG. with a spacing of 0.375
.ANG. between the two consecutive grids. In the docking process,
A.beta..sub.1-42 was kept rigid and cotinine was allowed to form all the
possible torsional bonds. The AutoDock Lamarkian genetic algorithm using
the standard protocol with 150 randomly placed individual initial
populations was applied. In total, 50 independent docking runs were
performed. The lowest energy conformer taken from the docked complex was
utilized to perform 50 nanosecond (ns) MD simulations on the
cotinine-A.beta..sub.1-42 complex in aqueous solution.
[0121] b) Molecular Dynamics (MD) simulations: All molecular dynamics (MD)
simulations were performed using the GROMACS software package, utilizing
the GROMACS force field (Berendsen et al. (1995); Lindahl et al. (2001)).
Dundee Pro Drug Server was used for generating the topology of the
cotinine molecule for the MD simulation and the partial charges were also
calculated using this server (Schuettelkopf and Van Aalten (2004)). The
A.beta..sub.1-42-cotinine complex was placed in the center of a box with
dimensions 4.9.times.4.2.times.4.6 nm. The box contained over 2852 single
point charge (SPC) water molecules. Some water molecules were replaced by
sodium and chloride ions to neutralize the system and to simulate an
experimentally used ion concentration of 150 mM. The starting structure
was subsequently energy minimized with a steepest descent method for 2000
steps. The results of these minimizations produced the initial structure
for the MD simulations. The MD simulations were then carried out with a
constant number of particles (N), pressure (P) and temperature (T), i.e.,
NPT ensemble. The SETTLE algorithm was used to constrain the bond length
and angle of the water molecules (Miyamoto and Kollman (1992)), while the
LINCS algorithm was used to constrain the bond length of the peptide
(Hess et al. (1997)). The long range electrostatic interactions were
calculated by the particle-mesh Ewald (PME) method (Darden et al. (1993);
York et al. (1994)). A constant pressure of 1 bar was applied with a
coupling constant of 1.0 ps; peptide, water molecules and ions were
coupled separately to a bath at 300.degree. K. with a coupling constant
of 0.1 ps. The periodic boundary conditions (PBC) were applied and the
equation of motion was integrated at time-steps of 2 femtoseconds (fs).
The secondary structure analyses were performed by employing the defined
secondary structures of proteins (DSSP) protocol (Kabsch and Sander
(1983)). The contact maps and similarity factor of the most
representative structures obtained from a cluster analysis have also been
employed as structural descriptors. A contact for a pair of amino acid
side chains is considered to be formed when a minimal distance between
any pair of their atoms is less than 0.5 nm. In the cluster analysis, the
trajectories are analyzed by grouping structurally similar frames
(root-mean-square-deviation (RMSD) cutoff=0.30 nm) (Daura et al. (1999)),
and the frame with the largest number of neighbors is denoted as a
"middle" structure, which represents that particular cluster.
Example 8
Cotinine is Neuroprotective Against A.beta. Toxicity
[0122] To investigate the effect of cotinine on A.beta. neurotoxicity, rat
cortical cells were grown in conditions that permitted us to obtain a
neuron-enriched culture (around 95% neuron and 5% glial cells) for 7-10
days. After this time, cortical cells that under microscopic examination
did not show signs of neurodegeneration, were incubated in
Neurobasal/B27-AO alone (control cells), and containing 5 .mu.M A.beta.,
or 5 .mu.M A.beta. plus various concentrations of cotinine. After 24 h,
cell survival was assessed by using MTT and PI and calcein-AM cell
viability assays.
[0123] We found that cotinine added together with A.beta. to the culture
media, at concentrations as low as 1 .mu.M, protected the cortical cells
against A.beta. toxicity. MTT assay results show that cotinine increased
cell survival at doses as low as 1 .mu.M. Maximal protection was attained
with cotinine 10 .mu.M that increased cell survival from 76% (A.beta.
alone) to 85% (A.beta.+10 .mu.M cotinine) of vehicle-treated control
cells (FIG. 7A). These differences were statistically significant
(Student's t test, A.beta.+10 .mu.M cotinine p=0.003) and representative
of more than three similar experiments.
[0124] Similar results were obtained when the cell viability changes were
tested using PI and calcein-AM assay. FIG. 7B shows that cotinine
increased neuronal survival after A.beta. exposure expressed as more
green fluorescent cells and decreased the number of nuclei of
degenerating brain cells that were stained by PI (red). Cotinine (10
.mu.M) protected cortical neurons against A.beta. toxicity and increased
cell survival from 63% (5 .mu.M A.beta. alone) to 83% (5 .mu.M A.beta.+10
.mu.M cotinine) of vehicle-treated control cells. This difference was
statistically significant (Student's t test, p=0.0007).
Example 9
Cotinine Prevented the Formation of Toxic Forms of A.beta.
Effect of Cotinine on A.beta. Aggregation
[0125] Previous evidence has suggested that cotinine inhibits A.beta.
aggregation into fibrils (Salomon et al. (1996)). Considering the
relevance in A.beta. neurotoxicity of the pre-fibrillar, oligomeric and
protofibrillar forms of the peptide, we investigated the effect of
cotinine on A.beta. aggregation into oligomers, protofibrils and fibrils.
[0126] The changes in monomer and oligomer concentrations were monitored
by Western blot and dot-blot immunoassays analysis, and fibril formation
was assessed by Atomic force microscopy (AFM) and X-ray microscopy.
[0127] For the analysis of A.beta. oligomerization, we used a protocol
that favors A.beta. oligomerization over fibrillation and consists of
dissolving the A.beta..sub.1-42 peptide in sodium hydroxide and further
diluting the solution with PBS as described in Experimental Procedures.
Previously, It has been reported that under similar conditions of
aggregation A.beta. fibers did not appear before 6 days of incubation at
RT (25.degree. C.), making the oligomeric forms predominant in the
solution in the absence of inhibitors (Necula et al. (2007)). Consistent
with this idea, the X-ray diffraction analysis of these solutions
confirmed the virtual absence of fibrils in the lyophilized samples and
after vapor-hydration, after 7 days of incubation at RT (Dr. Kirchner
personal communication).
[0128] After an oligomerization step at 25.degree. C. for 7 days, the
A.beta. solutions were analyzed by Western blot and dot-blot immunoassays
using 6E10 and A11 antibodies. The Western blot analysis showed that
co-incubation with ascending concentrations of cotinine increased the
levels of A.beta. monomers in the solutions after 5 and 7 days of
incubation. Dot-blot immunoassays were also performed on days 5 and 7 to
further illustrate the trend observed in the Western blots (FIG. 8A).
[0129] The subsequent analysis of the same A.beta. solutions on days 2 and
6 incubated at RT by dot-blot immunoassays using the same 6E10 antibody,
showed that A.beta. pre-incubated with increasing concentrations of
cotinine showed higher immunoreactivity for the 6E10 antibody (FIG. 8B),
which in these conditions of fibrillation, and in the use of a dot-blot
immunoassays, recognizes preferentially the monomeric form of the
peptide.
[0130] To investigate whether the increase in the 6E10 immunoreactivity in
the presence of cotinine was due to a decrease in the A.beta.
oligomerization, we also investigated the same solutions for the presence
of A.beta. oligomers by dot-blot immunoassays with the anti-oligorneric
A.beta. antibody A11. This antibody is highly specific for the oligomeric
forms of A.beta. and does not recognize the monomeric or fibrillar forms
of the peptide (Necula et al. (2007)). The results, from three
independent experiments for any condition, showed that the presence of
cotinine in the A.beta. solutions decreased the concentration of A.beta.
oligomers expressed as a decrease in the immunoreactivity for the A11
antibody. The decrease in A.beta. oligomers positively correlated with an
increase in the concentration of cotinine in the samples (FIG. 8B).
Example 10
Analysis of A.beta. Aggregation Using Atomic Force Microscopy
[0131] To investigate whether cotinine in addition to A.beta.
oligomerization also affected fibril formation, we used Atomic force
miscroscopy (AFM) to analyze A.beta. aggregation. The solutions were
prepared dissolving A.beta. in HFIP and after evaporation, in PBS alone
or containing cotinine and incubated at 37.degree. C. for 3 and 10 days.
[0132] FIGS. 9A-9E present AFM images (900.times.900 nm field) of
oligomers and fibrils of A.beta. formed after incubation in either the
absence (FIG. 9A and FIG. 9D) or presence cotinine (FIG. 9B) for 10 days.
The analysis of A.beta. fibril formation in the presence of cotinine
showed that cotinine reduced A.beta. aggregation and the length of
A.beta. fibrils. The average length of A.beta. fibrils incubated in the
absence of cotinine (345.+-.42, n=8) was higher than the average fibril
length in the presence of cotinine (223.+-.36, n=23). The difference in
A.beta. fibril length was statistically significant when analyzed using
Student-t test (p=0.0228). FIG. 9D shows the longest fibril observed in
the absence of cotinine, with a length of 1.75 .mu.m and a diameter of
34.3 nm. FIG. 9E represents the image obtained in a control experiment
with PBS alone. Under our experimental conditions, the average diameter
of the fibers did not change due to the presence of cotinine, and
fluctuated between 22-24 nm. The average height of the aggregates
fluctuated between 15-25 nm.
Example 11
Effect of Cotinine on A.beta. Toxicity
[0133] First, we performed x-ray analysis to investigate the presence of
A.beta..sub.1-42 fibrils in our solutions prepared using conditions that
favor the oligomerization of the peptide and incubated for 3 days at
25.degree. C. The x-ray analysis of lyophilized A.beta..sub.1-42 before
incubation showed scatter only from buffer salts (data not shown). The
absence of x-ray spacing from any .beta.-conformation indicates that the
initial peptide was unstructured. After vapor-hydration of the
lyophilized peptide solution that had been incubated for 3 days at RT, we
detected only very weak reflections indicative of .beta.-sheet
conformation (FIG. 10). Considerably longer incubation results in more
pronounced spacing from .beta.-structure (FIG. 10, inset).
[0134] To investigate whether the inhibition of A.beta. oligomerization
induced by cotinine affected A.beta. toxicity, we performed toxicity
assays using solutions prepared by pre-incubating the peptide in the
presence or absence of ascending concentrations of cotinine under
conditions that favor A.beta. oligomerization for 3 h at 4.degree. C. and
cell viability was assessed by using the MTT assays described in the
Materials and Methods section. The results show that when the A.beta.
solutions were pre-incubated in the absence of cotinine, and then added
to the cells, the further addition of cotinine to the culture media was
not able to block A.beta. neurotoxicity (FIG. 11A). However, when A.beta.
was dissolved and incubated in the presence of ascending concentrations
of cotinine (1, 5, 10, and 25 .mu.M), the procedure significantly reduced
A.beta. neurotoxicity (FIG. 11B). We found that maximal protection was
attained by pre-incubating 10 .mu.M A.beta. in the presence of 10 .mu.M
cotinine. Cortical cells treated with A.beta. plus cotinine (10 .mu.M)
had higher viability (87.3%.+-.12.4) than cells treated with A.beta.
alone (66%.+-.3.6) (22% increase). This increase in cell viability
induced by cotinine was significant (Student's t test, P=0.019). Similar
results were obtained in at least two experiments performed in identical
conditions, but run with different batches of cortical cells. Taken
together, this analysis suggests that the appearance of aggregated toxic
forms of A.beta. start to develop as early as after 3 h of incubation at
temperatures as low as 4.degree. C., and that cotinine effectively
inhibited the conversion of the peptide to its toxic forms.
Example 12
Effect of Cotinine on Cell Signaling Involved in Neuronal Survival
[0135] BDNF is a pro-survival neurotrophic factor that promotes neuronal
survival and stimulates synaptic plasticity involved in learning and
memory and is affected in AD (Ferrer et al. (1999); Tong et al. (2004)).
To determine whether cotinine positively affects the BDNF-stimulated CREB
phosphorylation after A.beta. exposure, cells were incubated with 5 .mu.M
A.beta..sub.1-42 alone or 5 .mu.M A.beta..sub.1-42+10 .mu.M cotinine for
5 h. After this time, cells were stimulated with BDNF for 1 h and whole
cell extracts were analyzed for the expression of CREB phosphorylated at
serine 133 by western blot. We found that cotinine suppressed the
A.beta.-dependent inhibition of the BDNF-stimulated CREB phosphorylation
at Serine 133 (FIG. 12). The levels of phosphoCREB in the
A.beta..sub.1-42 treated cells were significantly lower (41% decrease,
.+-.10) than the levels found in the control cells considered 100%
imunoreactivity (.+-.10) (One-way ANOVA, P<0.05). Cotinine treatment
significantly increased these levels to values indistinguishable from the
control cell values, and significantly higher (34% increase) than the
expression found in cells treated with BDNF plus A.beta..sub.1-42
(One-way ANOVA, P<0.05).
Example 13
Molecular Modeling of Cotinine-A.beta. Interaction
[0136] The RMSD of the MD simulation confirmed that the complex is
thermodynamically equilibrated only after 30 ns (FIG. 13). The most
representative structure derived from the simulation indicates that
cotinine interacts with His6, Tyr10 and His14 residues of the
A.beta..sub.1-42 peptide (FIG. 14A). As shown in the figure, the pyridine
ring of cotinine is positioned between the imidazole ring of His6 and the
phenyl ring of Tyr10. It interacts with these residues through strong
.pi.-.pi. interactions that are indicated by the distances of 4.3 .ANG.
and 4.1 .ANG. between cotinine--His6 and cotinine-Tyr10 aromatic rings,
respectively (FIGS. 14B and 14C). In the equilibrated region, the
distance between the center of the aromatic ring of Tyr10 and the
pyridine ring of cotinine remains around 4.0 .ANG. (FIG. 14D). On the
other hand, cotinine interacts with His14 via C--H-.pi. interaction
((cotinine-C)--H-His14=3.2 .ANG.), (FIGS. 14B and 14C). As discussed
below, the interactions of cotinine with His6, Tyr10 and His14 residues
of A.beta..sub.1-42 introduce significant changes in the secondary
structure of the peptide.
[0137] In the free A.beta..sub.1-42 peptide, in the first 38 ns, the
Phe20-Val24 region is dominated by bend and turn conformations with
sporadic helical structures (FIG. 15A). After that it is transformed into
bend and coil structures. However, in the cotinine bound structure, for
the first 25 ns this region exists in helical conformation but it is
later converted into the stable turn structure (shown by the yellow color
in FIG. 15B). In the free peptide, the loop region (24-28, VGSNK) is
quite unstable and undergoes a large dynamical transformation between
bend and turn. In the presence of cotinine, in a marked difference,
initially (for the first 22 ns) this segment exists in the helical form
but later it adopts stable bend and coil conformations. The second
hydrophobic domain (29-35, GAIIGLM) in free A.beta..sub.1-42 is dominated
by the bend structure for the first 28 ns but after that it is converted
into a turn with a partial .beta.sheet character. On the other hand, in
the cotinine bound structure, the Gly29-Ile32 fragment of this region
stays in the stable helical form throughout the simulation. The remaining
Leu33-Met35 segment, after 28 ns, is transformed into the stable bend
conformation.
Example 14
Cotinine Stimulated BDNF-Induced Arc Expression in Primary Cortical
Neurons
[0138] The BDNF-stimulated expression of Arc plays a key role in learning
and memory. Interestingly, it has been recently reported that Arc
expression is upregulated in the hippocampus of rodents with decreased
retention of fear memories. Our results show that cotinine enhances the
BDNF-induced expression of Arc in cultured cortical neurons (FIGS.
16A-16B). We hypothesize that if cotinine increases the neuronal
expression of Arc in vitro, it can also have the potential to decrease
the retention of fear memories in vivo.
[0139] We also determined the effect of cotinine on the neuronal
expression of two protein kinases, Jun kinase (JNK) and the extracellular
regulated kinase (ERK1/2), which negatively and positively, respectively,
regulate neuronal survival.
[0140] We found that cotinine decreased the levels of the active forms of
JNK1/2 phosphorylated (pJNK) at Thr183 and Thr185, that were induced by
BDNF (FIGS. 17A-17D). Since JNK promotes cell death, this decrease is
coherent with the cotinine-induced reduction of neuronal cell death after
A.beta. exposure. The actions of cotinine seems to be mediated by defined
cell signaling mechanisms different from that of nicotine as cotinine did
not affect the BDNF-stimulated phosphorylation of ERK, a well known
target of nicotine activation of nicotinic acetylcholine receptors
(nAChR).
Example 15
Cotinine Decreased the Retention of Fear Memories
[0141] To study the effect of cotinine on contextual fear memory, we
pretreated mice with vehicle or cotinine at 1 and 5 mg/kg/day for 8 days.
After this time, mice were trained for contextual fear conditioning (FC).
Briefly, mice were trained to associate the context (the chamber) with an
aversive unconditioned stimulus (1 mA foot shock for 2 seconds). After
the FC training, the mice were re-exposed to the context every day for 7
consecutive days. The mice were treated daily with vehicle or cotinine at
1 and 5 mg/kg during the FC training and re-exposure to the context. The
fear memory of the mice expressed as freezing behavior was assessed each
day after re-exposure to the context. The fear memory after 24 h of the
FC training is considered a measure of retention of the fear memory. The
reduction of fear memory expressed as a reduction in the freezing
behavior after the retention trial is evaluated as the extinction of the
fear memory.
[0142] The results show that cotinine treatment decreases the retention
and promotes the extinction of fear memories expressed as a decrease in
the freezing behavior in the retention test and in the last day of the
memory extinction test (FIG. 18). The lower dose of cotinine (1 mg/kg)
was more effective in decreasing the freezing behavior in the retention
test. Thus, mice treated with 1 mg/kg/day of cotinine showed a
significantly lower percentage of freezing (Student's t test, p=0.0191)
compared to mice treated with vehicle. However, higher doses of cotinine
(5 mg/kg/day) were more effective at increasing the extinction of the
fear memory. Thus, mice treated with cotinine at 5 mg/kg showed a
significantly lower percentage of freezing compared to mice treated with
vehicle (Student's t test, p=0.0218). The changes observed in the
retention test in the mice pretreated with cotinine can reflect changes
in the acquisition, consolidation, and recall of the fear memory.
Additional experiments will be required to determine these possibilities.
However, the decrease in the freezing behavior in mice treated with
cotinine 5 mg/kg at day 6 suggests that cotinine facilitates the
extinction of fear memory in these mice.
Example 16
Effect of Cotinine on Anxiety as Evaluated Using the Elevated Plus Maze
[0143] The elevated plus maze (EPM) is considered the first choice test
for screening anxiolytic effects of drugs. This test is based on the fact
that higher anxiety levels will decrease the drive to explore a new
environment as a way to avoid a potentially dangerous areas (open arms),
and will, therefore, cause the mice to stay immobile in the closed arms
for a longer period of time.
Example 17
Effect of Cotinine on Anxiety in a Fear-Provoking Environment
[0144] To determine the effect of cotinine on anxiety, mice were tested
for anxiety behavior using the EPM. The results showed that cotinine did
not change the time spent exploring the maze (FIG. 19A, One-way ANOVA,
F(2,21)=0.1250, p=0.8831), neither the time spent on both open (FIG. 19B,
One-way ANOVA, F(2,21)=0.8367, p=0.4471) and closed arms (FIG. 19C,
One-way ANOVA, F(2,21)=0.4914, p=0.6186). These results suggest that
cotinine does not affect anxiety levels in mice under resting conditions.
Example 18
Effect of Cotinine on Fear-Induced Anxiety
[0145] To determine the effect of cotinine treatment on the levels of
anxiety in the mice after re-exposure to a fear memory, we performed the
same EPM test but 24 h after fear conditioning training (shock in the
chamber) and immediately after re-exposure to the context (chamber), a
reminder of the unconditioned aversive stimulus (the electric shock).
[0146] We found significant differences between the groups in the time
spent exploring (FIG. 20A, One-way ANOVA F(2,21)=7.573 p=0.0033), time
spent in the open arms (FIG. 20B, One-way ANOVA F(2,20)=5.888 p=0.0098),
and time spent in the closed arms (FIG. 20C, One-way ANOVA F(2,21)=6.474
p=0.0065). The mice trained for FC and treated with vehicle spent
significantly less time exploring when compared with mice treated with
cotinine at 1 mg/kg (FIG. 20A, Student's t test, p=0.0145) and 5 mg/kg
(p=0.0025). Also, mice trained for FC and treated with vehicle spent
significantly less time in the open arms than mice subjected to FC and
treated with 1 mg/kg cotinine (FIG. 20B, Student's t test, p=0.0101) but
no significant differences with mice treated with cotinine at 5 mg/kg
(p=0.0545). In coherence with these results, mice trained for fear
conditioning spent less time in the closed arms (FIG. 20C). This
difference was highly significant when the untreated mice were compared
to mice treated with cotinine 1 mg/kg (Student's t test, p=0.0060) and 5
mg/kg (p=0.0111).
Example 19
Effect of Cotinine on Motor Coordination in Mice
[0147] To discard a confounding effect of cotinine on learning due to
changes in motor coordination and fatigue, we tested mice in the rotarod
test after 2 weeks of treatment with vehicle or cotinine at the doses
indicated in the figure below.
[0148] The analysis of the results shows that the differences in latency
between groups to fall on the first and second day were not significant.
Two weeks of cotinine treatment did not affect sensorimotor abilities in
the mice. Similar to this test, no changes in sensorimotor abilities were
detected by using the open field activity test (data not shown).
Example 20
[0149] It has been discovered using cultured cortical neurons that
cotinine inhibits A.beta. oligomerization in vitro and prevents its
toxicity on cortical neurons. Studies performed in vitro have shown that
cotinine binds to A.beta. with high affinity. Cotinine can also bind
A.beta. in vivo with high affinity and consequently, when labeled for
detection by Positron Emission tomography, it can be used as a diagnostic
tool to determine the presence of senile plaques in the brain of AD
patients.
[0150] It should be understood that the examples and embodiments described
herein are for illustrative purposes only and that various modifications
or changes in light thereof will be suggested to persons skilled in the
art and are to be included within the spirit and purview of this
application and the scope of the appended claims. In addition, any
elements or limitations of any invention or embodiment thereof disclosed
herein can be combined with any and/or all other elements or limitations
(individually or in any combination) or any other invention or embodiment
thereof disclosed herein, and all such combinations are contemplated with
the scope of the invention without limitation thereto.
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