Alcohol Pathogenesis in CNS Microglial Cells

描述(由申请人提供)： 在美国，大约1%的新生儿会出现胎儿酒精综合症和相关的疾病，这是导致智力低下的主要非遗传原因。我们知识中的一个主要差距是缺乏对酒精对神经元和胶质细胞之间关系的影响的了解。为了解决这一差距，我们正在研究胶质细胞在酒精介导的神经毒性中的作用，重点是小胶质细胞和小脑神经元之间的通讯。我们在酒精暴露的新生大鼠模型上进行的初步研究显示，单剂量酒精可导致大约40%的小胶质细胞丢失。在培养中，我们发现中等水平的酒精抑制了细胞的增殖，并导致显著的小胶质细胞死亡。此外，这些研究还证实了PPARGamma信号通路是酒精诱导的小胶质细胞死亡的特异性靶点，并证明了PPARGamma的药理激动剂可以有效地预防酒精诱导的小胶质细胞死亡。小胶质细胞和小脑颗粒细胞共培养的分析表明，小胶质细胞对酒精诱导的神经元死亡具有积极的保护作用，也可以防止酒精诱导的轴突丢失。这些发现表明，发育中的大脑中的小胶质细胞可能为神经元提供免受酒精毒性的保护，而体内酒精暴露期间小胶质细胞的急剧丧失可能导致神经元对酒精的脆弱性。我们将研究这一假设，即酒精对发育中的大脑小胶质细胞的毒性可以通过激活PPARγ来阻止，同时保留小胶质细胞的神经保护活性。初步研究中使用的体内补充模型(新生大鼠胎儿酒精暴露模型)和体外模型(新生大鼠小胶质细胞和小脑颗粒细胞的纯化培养)将用于验证这一假说。我们将评估PPARγ激动剂在体内预防酒精毒性的能力，包括小胶质细胞、颗粒细胞和浦肯野细胞的丢失。小胶质细胞分泌的神经保护因子将被识别出来。PPARγ激活对小胶质细胞产生保护因子的潜在影响将被确定。这些研究的结果将为了解小胶质细胞在产前酒精暴露中的潜在神经保护作用以及PPARy信号转导通路在酒精中毒中的参与提供第一个了解。这一知识的应用可能为预防或治疗与产前酒精暴露相关的神经病理提供新的治疗策略。

DESCRIPTION (provided by applicant): Fetal alcohol syndrome and related disorders occur in approximately 1% of births in the U.S. and are the leading non-genetic cause of mental retardation. A major gap in our knowledge is lack of understanding of the effect of alcohol on the relationship between neurons and glia. To address this gap, we are investigating the role of glia in alcohol-mediated neurotoxicity, with a specific focus on communication between microglial cells and cerebellar neurons. Our pilot studies in the neonatal rat model of alcohol exposure revealed a single dose of alcohol caused approximately 40% loss of microglia. In cultures, we found that moderate levels of alcohol inhibited proliferation and produced significant microglial death. In addition, these studies identified the peroxisome proliferator activated receptor gamma (PPARgamma) signaling pathway as a specific target of alcohol in microglia and demonstrated effective prevention of alcohol-induced microglial death with a pharmacologic agonist of PPARgamma. Analyses of co-cultures of microglia and cerebellar granule cells demonstrated that microglia actively protect neurons from alcohol-induced death and also prevent alcohol-induced neurite loss. These findings suggest that microglia in the developing brain may provide protection for neurons against alcohol toxicity, and that the dramatic loss of microglia in vivo during alcohol exposure may contribute to neuronal vulnerability to alcohol. We will investigate the hypothesis that alcohol toxicity in microglia in the developing brain can be blocked by activation of PPARgamma, with preservation of microglial neuroprotective activity. The complementary in vivo (neonatal rat model of fetal alcohol exposure) and in vitro (purified cultures of microglia and cerebellar granule cells from neonatal rat) models used in the pilot studies will be employed to test this hypothesis. We will evaluate the ability of PPARgamma agonists to prevent alcohol toxicity in vivo, including loss of microglia, granule cells and Purkinje cells. The neuroprotective factors secreted by microglia will be identified. The potential effect of PPARgamma activation on microglial production of protective factors will be determined. Results of these studies will provide the first understanding of the potential neuroprotective role of microglia during prenatal alcohol exposure and the involvement of the PPARy signal transduction pathway in alcohol toxicity. Application of this knowledge may provide new therapeutic strategies for prevention or treatment of the neuropathology associated with prenatal alcohol exposure.