Cell Models for AD: Lipids and Related Signaling Pathways

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DESCRIPTION (provided by applicant): The major goal of this Program Project Grant (PPG) is to explore novel and under-studied pathways that contribute to Alzheimer's disease (AD). The decreased neuronal plasticity and cognitive memory loss found in people with AD is associated with chronic oxidative stress and increased production of neurotoxic oligomeric amyloid beta (A?) that cause release of cytokines and other molecules that promote neurodegeneration and chronic inflammation. We believe that devising methods to limit chronic effects of oxidative stress and oligomeric A? production would have profoundly positive consequences for AD patients. Based on promising results in the current grant period, we propose to better understand the mechanisms underlying the effects of oxidative stress and A? in neurons and glial cells, information that will lead to better treatments for prevention of neurodegeneration and chronic inflammation in the AD brain. We will investigate neuroprotective and pro-inflammatory pathways in neurons, glia and brain microvessels using cell and animal models of AD. Three projects will test the hypotheses that: (1) progression of AD involves expression and activation of the cPLA?/sPLA2/NADPH oxidase pathways to induce inflammatory responses in glial cells and impairment of neuronal functions; (2) chronic inflammation in AD is mediated by P2Y2 receptors (P2Y2Rs) for cytokine-like nucleotides in astrocytes and cerebral microvessels through transactivation of integrins and growth factor receptors, and P2Y2Rs mediate neuroprotective APP processing by a different pathway than inflammation; and (3) statins have both cholesterol-independent and -dependent mechanisms of action that are neuroprotective due to drug-induced transcriptional up-regulation of anti-apoptotic Bcl-2 by ET- 1/calcinurin/NFAT-dependent pathways and inhibition of Rac1 geranylgeranylation. Two cores will support the projects: (A) Administrative Core A will oversee progress on the PPG; (B) Cell, Molecular, and Animal Core B will provide standardized preparations of primary cell cultures and transfectants, and transgenic mice, prepare tissue sections, and perform immunohistochemical analyses, Laser Capture Microdissection, microarray screening of gene expression, and molecular biology assays. These collaborative studies should identify novel strategies to control chronic inflammation and neurodegeneration in AD. RELEVANCE: Dementia is a brain disorder that seriously affects a person's ability to carry out daily activities. The most common form of dementia among older people is Alzheimer's disease (AD), which initially involves the parts of the brain that control thought, memory, and language. Up to 4.5 million Americans suffer from AD from which there is no cure.