Alzheimer's disease (AD) is a devastating neurodegenerative disorder that afflicts millions of people worldwide. Two major features of AD are: (1) degeneration of basal forebrain cholinergic neurons and ensuing deficient cholinergic functions in cortex and hippocampus; (2) extracellular protein aggregates containing beta-amyloid peptides (Abeta) in these cholinergic target areas. So far, the most effective therapeutic strategy in AD treatment is to enhance cholinergic transmission. Neuromodulatory functions of the cholinergic system are mainly mediated by muscarinic receptors (mAChRs). It has long been recognized that mAChRs are crucial for the control of high-level cognitive processes. Drugs that activate mAChRs are helpful in ameliorating cognitive deficits of AD. Despite the discovery of correlation between cholinergic hypofunction and AD, the cellular and molecular mechanisms underlying the function and dysfunction of mAChRs in normal cognition and dementia remain elusive. The long-term goals of this project are to understand (1) how muscarinic signaling is involved in the regulation of neuronal activity and synaptic transmission in frontal cortex, which is critical for learning and memory under normal condition; and (2) how this regulation is altered in animal models that simulate cognitive and memory impairments associated with AD. Recent evidence indicates that GABAergic inhibition in frontal cortex plays an important role in """"""""working memory"""""""" by controlling the timing of neuronal activities during cognitive operations. We hypothesize that the GABAA receptor channel is potentially a key cellular substrate for muscarinic signaling in cognition and memory, and disruption of its regulation by mAChRs in AD might contribute to the cognitive impairment. Transgenic mice overexpressing a mutant gene for beta-amyloid precursor protein (APP) show behavioral and histopathological abnormalities resembling AD, and therefore will be used as an AD model in our experiments. Emerging evidence suggests that Abeta plays pleiotropic roles in the regulation of cholinergic functions in cortex. We hypothesize that the muscarinic modulation of GABAA receptor function is lost in AD models due to the interference of Abeta on muscarinic signaling. Combined electrophysiological, pharmacological, biochemical and molecular analyses will be used to test these hypotheses. This research would shed some light on how the two prominent features of AD (cholinergic hypofunction and Abeta accumulation) may be linked to cause cognitive impairments. Such knowledge should offer important insights into the cellular and molecular basis of AD and the development of new pharmacological agents in the treatment of this disease.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
1R01AG021923-01
Application #
6596596
Study Section
Special Emphasis Panel (ZRG1-MDCN-4 (01))
Program Officer
Snyder, Stephen D
Project Start
2003-06-15
Project End
2008-05-31
Budget Start
2003-06-15
Budget End
2004-05-31
Support Year
1
Fiscal Year
2003
Total Cost
$351,974
Indirect Cost
Name
State University of New York at Buffalo
Department
Physiology
Type
Schools of Medicine
DUNS #
038633251
City
Buffalo
State
NY
Country
United States
Zip Code
14260
Chen, Guo-Jun; Xiong, Zhe; Yan, Zhen (2013) A? impairs nicotinic regulation of inhibitory synaptic transmission and interneuron excitability in prefrontal cortex. Mol Neurodegener 8:3
Liu, Wenhua; Dou, Fei; Feng, Jian et al. (2011) RACK1 is involved in ?-amyloid impairment of muscarinic regulation of GABAergic transmission. Neurobiol Aging 32:1818-26
Mandal, Madhuchhanda; Yan, Zhen (2009) Phosphatidylinositol (4,5)-bisphosphate regulation of N-methyl-D-aspartate receptor channels in cortical neurons. Mol Pharmacol 76:1349-59
Gu, Zhenglin; Liu, Wenhua; Yan, Zhen (2009) {beta}-Amyloid impairs AMPA receptor trafficking and function by reducing Ca2+/calmodulin-dependent protein kinase II synaptic distribution. J Biol Chem 284:10639-49
Yuen, Eunice Y; Ren, Yi; Yan, Zhen (2008) Postsynaptic density-95 (PSD-95) and calcineurin control the sensitivity of N-methyl-D-aspartate receptors to calpain cleavage in cortical neurons. Mol Pharmacol 74:360-70
Chen, Guojun; Chen, Paul; Tan, Huibing et al. (2008) Regulation of the NMDA receptor-mediated synaptic response by acetylcholinesterase inhibitors and its impairment in an animal model of Alzheimer's disease. Neurobiol Aging 29:1795-804
Chen, Paul; Gu, Zhenglin; Liu, Wenhua et al. (2007) Glycogen synthase kinase 3 regulates N-methyl-D-aspartate receptor channel trafficking and function in cortical neurons. Mol Pharmacol 72:40-51
Chen, Guojun; Kittler, Josef T; Moss, Stephen J et al. (2006) Dopamine D3 receptors regulate GABAA receptor function through a phospho-dependent endocytosis mechanism in nucleus accumbens. J Neurosci 26:2513-21
Gu, Zhenglin; Jiang, Qian; Yuen, Eunice Y et al. (2006) Activation of dopamine D4 receptors induces synaptic translocation of Ca2+/calmodulin-dependent protein kinase II in cultured prefrontal cortical neurons. Mol Pharmacol 69:813-22
Tyszkiewicz, Joanna P; Yan, Zhen (2005) beta-Amyloid peptides impair PKC-dependent functions of metabotropic glutamate receptors in prefrontal cortical neurons. J Neurophysiol 93:3102-11

Showing the most recent 10 out of 20 publications