Complications of alcoholism such as stroke and cardiomyopathy are leading causes of death among adults. The underlying pathophysiology of these events involves lipids within susceptible arteries leading to subsequent localized inflammation and vascular dysfunction. The human brain is composed of approximately 60%?70%lipids by dry weight. While the bioactive glycerophospholipid lysophosphatidic acid plays a well- known role in atherosclerotic disease, its role in alcohol-mediated cerebral dysfunction remains virtually unexplored. Lysophosphatidic acid production involves hydrolysis of lysophosphatidylcholine by the secreted enzyme autotaxin, whereas lipid phosphate phosphatase-3 (LPP3) catalyzes lysophosphatidic acid dephosphorylation to generate lipid products that are not receptor active. In this application, we present the first evidence that heavy alcohol consumption (HAC) enhances the cerebrovascular autotaxin levels and decreases LPP3 expression, and this is associated with increased lysophosphatidic acid signaling. Upon HAC, reactive oxygen species (ROS) increases in the cerebrovasculature, whereas the redox-sensitive transcription factor NFAT (a nuclear factor of activated T-cells) has been shown to bind to the autotaxin promoter and induce its expression. Similarly, oxidant stress may deplete LPP3 levels in the context of HAC through reduced LPP3 expression or enhanced LPP3 degradation. Increased autotaxin expression found in the frontal cortex of Alzheimer?s patients suggests that altered lysophosphatidic acid metabolism might contribute to the pathology of the disease. Recent studies have shown a positive correlation between cerebrospinal fluid (CSF) levels of A? and oxLDL in AD patients, suggesting oxLDL may affect A? production. Lysophosphatidic acid, the most bioactive component of oxidized low-density lipoprotein (oxLDL) induces increased production of the B-amyloid peptide but the question remains about the lysophosphatidic acid regulatory enzyme in Alzheimer disease. The following interrelated specific aims are designed to provide step- wise and in-depth studies in vitro, in vivo, and in experimental therapeutics settings.
Specific aim 1 will assess the role of ROS production in autotaxin expression and Alzheimer?s disease progression following HAC.
Specific aim 2 will determine the role of ROS production in LPP3 depletion and Alzheimer?s disease progression following HAC. We could identify whether modulation of cellular versus mitochondrial antioxidant status confers a differential protective effect following HAC. We could identify whether modulation of autotaxin and LPP3 confers a differential protective effect following HAC and Alzheimer disease risk. Our results should provide specific insight into signaling systems mediated by HAC and may provide novel targets for treatment and might improve cerebrovascular disorders.
Health problems associated with alcohol consumption have reached alarming levels, and alcohol use contributes to a wide range of diseases, from mental disorders, liver diseases and cerebrovascular disorders. Heavy drinking, especially bingeing leads to lipid profile changes and its signaling in the brain. People with lipid profile disorders are highly susceptible to these alcoholic disorders. The proposed study will not only extend our understanding of the fundamental mechanism by which alcohol regulates cellular events leading to cerebrovascular dysfunction but will also identify novel targets for future clinical interventions.
