Binge alcohol-induced neurodegeneration and omega-3 DHA Protection

描述(申请人提供)：长期酗酒会导致大脑损伤，但机制尚不清楚。从成年大鼠在体和大鼠脑片培养的研究中，我们知道，长期酗酒(酒精)暴露和戒断(“酒精”水平，70-120 mM)会引起海马神经元/皮质神经变性，这种变性：(A)不典型的兴奋性毒性；(B)导致脑水肿(利尿剂防止浮肿和神经损伤)；(C)涉及氧化应激(抗氧化剂神经保护)；以及(D)需要磷脂酶A2(PLA2)激活，从而动员(JO-6花生四烯酸(AA)，一种自由基源(PLA2抑制剂可以减少神经损伤)。值得注意的是，u)-3脂肪酸二十二碳六烯酸(DHA)抑制AA的释放并提供神经保护。与此同时，NIAAA内部调查员、DHA/酒精研究先驱H.Y.Kim的研究表明，酒精诱导的细胞凋亡神经损伤存在相关的基于脂肪的机制，包括含DHA的磷脂酰丝氨酸(PS)的耗尽和促生存信号的减少，这些也可以通过补充DHA来防止。在Kim博士的合作下，这个U01应用程序探索了这两种神经退行性机制之间的功能联系，以及DHA保护是如何实现的。我们建议使用长期暴露在酗酒/戒断中的成年(与通常的青少年相反)大鼠海马区/内嗅皮层脑片培养的三个目标进行研究；技术包括生物转染法、反义寡核苷酸和高效液相/质谱仪分析。目的I：酒精诱导的膜PS、DHA含量和下游促生存蛋白激酶(Akt、RAF-1)活性降低是否导致随后的神经变性/凋亡？目的2：酒精引起的水肿、磷脂酶A2激活、AA动员和氧化应激导致的神经变性是否与酒精引起的膜氨基磷脂和存活激酶活性的变化有关？和目标3：酗酒时补充DHA的神经保护是否导致DHA掺入/增强膜PS，增加促生存信号，降低PLA2活性，并减少AA释放/氧化应激？目标1和目标3中的脂质分析在Kim博士的NIAAA实验室完成；所有其他研究都在洛约拉大学完成。相关性(参见说明)：这项U01合作研究长期酗酒的潜在神经炎性、基于脂质的脑毒性机制和DHA神经保护有望产生营养和其他见解，这些见解在减少酒精滥用和戒酒中的神经退化和脑功能障碍方面具有治疗价值。

DESCRIPTION (provided by applicant): Prolonged alcohol abuse causes brain damage, but the mechanisms remain uncertain. From studies with adult rats in vivo and rat brain slice cultures, we know that chronic binge alcohol (ethanol) exposure and withdrawal ("alcoholic" levels, 70-120 mM) cause hippocampal/cortical neurodegeneration that (a) is not typically excitotoxic; (b) entails brain edema (diuretics prevent the edema and neurodamage); (c) involves oxidative stress (antioxidants neuroprotect); and (d) requires phospholipase A2 (PLA2) activation, which mobilizes (JO-6 arachidonic acid (AA), a free radical source (PLA2 inhibitors reduce neurodamage). Notably, u)-3 fatty acid docosahexaenoic acid (DHA) suppresses AA release and provides neuroprotection. Meanwhile, research by H.Y. Kim, NIAAA intramural investigator and DHA/alcohol research pioneer, indicates a related "lipid-based" mechanism of alcohol-induced apoptotic neurodamage involving depletion of DHA-containing phosphatidylserine (PS) and reduced pro-survival signaling that are also prevented by DHA supplementation. With Dr. Kim's collaboration, this U01 application explores functional connections between these two neurodegenerative mechanisms, and how DHA protection is realized. We propose to research three aims, posed here as questions, using adult-age (as opposed to usual adolescent) rat organotypic hippocampal/ entorhinal cortical slice cultures chronically exposed to binge alcohol/ withdrawal; techniques include biolistic transfection, antisense oligos and HPLC/MS analysis. Aim I: Are alcohol-induced reductions of membrane PS, DHA content and downstream pro-survival kinase (Akt, raf-1) activities causative events in subsequent neurodegeneration/apoptosis? Aim 2: Are alcohol-induced edema, PLA2 activation, AA mobilization and oxidative stress leading to neurodegeneration coupled to alcohol-induced changes in membrane aminophospholipids and survival kinase activities? and Aim 3: Does DHA-supplemented neuroprotection during binge alcohol entail DHA incorporation into/ potentiation of membrane PS, increased pro-survival signaling, reduced PLA2 activity and diminished AA release/oxidative stress? The lipid analyses in Aims 1 & 3 are accomplished in Dr. Kim's NIAAA laboratory; all other research is at Loyola University. RELEVANCE (See instructions): This U01 collaborative study of chronic binge alcohol's potential neuroinflammatory, lipid-based mechanisms of brain toxicity and DHA neuroprotection holds the promise of yielding nutritional and other insights that can be therapeutically valuable in reducing neurodegeneration and brain dysfunction in alcohol abuse and withdrawal.