ROLE OF GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE IN DEPRESSION & ALCOHOLISM

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 研究中心，而研究中心不一定是研究者所在的机构。 抑郁症和酒精中毒越来越被理解为使人衰弱的，往往是致命的疾病，并且共同发生的概率比预期的要高。在重度抑郁症和酒精中毒中观察到的神经元和神经胶质细胞损失的分子机制仍不清楚。最近的研究集中在甘油醛-3-磷酸脱氢酶（GAPDH），一种传统的糖酵解酶的凋亡作用。几个研究小组已经报道，当细胞受到应激时，GAPDH易位到细胞核中。我们的初步数据表明，细胞应激或乙醇增加的表达， GAPDH在脑源性细胞系中的表达增加，并且还增加GAPDH与早期生长反应-1（Egr-1）的结合，导致GAPDH/Egr-1复合物的核转位。用细胞应激物和乙醇两者处理脑源性细胞系增加GAPDH表达和GAPDH/Egr-1的相互作用，比单独用细胞应激物或乙醇处理更多。我们的试验数据还表明，与正常对照受试者相比，患有抑郁症和酒精中毒的受试者的前额叶皮层中GAPDH水平比患有抑郁症和酒精中毒的受试者的前额叶皮层中GAPDH水平更高。 抑郁症或酗酒的受试者。在本申请中，我们提出了一种新的GAPDH介导的 可能涉及GAPDH与Egr-1结合的神经元应激途径。一旦进入细胞核，GAPDH Egr-1复合物分离，Egr-1靶向单胺氧化酶B（MAO B）基因，从而增加MAO B的表达。然后，MAO B酶促降解许多神经递质，产生有毒的活性氧（H2 O2）并导致神经元细胞应激，其促进细胞死亡或凋亡。 我们假设GAPDH-Egr-1-MAO-B介导的神经元应激通路有助于抑郁症和酒精中毒的发病机制，并且在抑郁症和酒精中毒的共病中比单独的抑郁症或酒精中毒更明显。我们进一步假设，抑制GAPDH-Egr-1-MAO-B介导的神经元应激途径将保护脑细胞免受有害的应激和乙醇诱导的影响。 我们的具体目标是：（1）通过测量细胞凋亡标记物来表征在GAPDH-Egr-1-MAO-B介导的神经元应激途径中有活性的组分（片段化DNA）和Egr-1和MAO B水平（GAPDH的下游靶点）在来自应激或乙醇处理的大鼠的前额叶皮层中的表达，与未处理的对照相比;（2）检测凋亡标志物的表达（片段化DNA）、GAPDH及其下游靶点在酒精性抑郁症受试者死后脑组织中的表达，并与抑郁症受试者、酒精依赖受试者和正常对照受试者比较;和（3）破坏GAPDH-Egr-1-MAO-B介导的神经元应激途径（使用siRNA），以检验抑制GAPDH将减少细胞应激物和乙醇的有害作用的假设。 这些研究与其他CPN项目相关，因为过量的谷氨酸信号传导（子项目2）已被报道触发GAPDH介导的神经元细胞死亡级联反应。GAPDH-Egr-1-MAO-B通路可能导致这种死亡级联反应，导致重度抑郁症患者脑细胞丢失（子项目1）。此外，GAPDH影响MAO的遗传调节，MAO是降解5-羟色胺的关键酶。因此，阐明GAPDH-Egr- 1-MAO-B介导的神经元应激/细胞死亡途径可能为5-羟色胺系统功能障碍提供新的见解（子项目3和4），并可能导致抑郁症和酒精中毒共病的新的治疗策略。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Depression and alcoholism are increasingly understood as debilitating and oftentimes fatal disorders, and co-occur more commonly than expected by chance. The molecular mechanisms contributing to observed neuronal and glial cell loss in both major depressive disorder and alcoholism remain unclear. Recent studies have focused on the apoptotic role of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a traditional glycolytic enzyme. Several groups have reported that GAPDH translocates into the cell nucleus when cells are stressed. Our preliminary data show that cell stressors or ethanol increase the expression of GAPDH in brain-derived cell lines and also increase the binding of GAPDH with early growth response-1 (Egr-1), resulting in nuclear translocation of the GAPDH/Egr-1 complex. Treatment of brain-derived cell lines with both cell stressors and ethanol increases GAPDH expression and the interaction of GAPDH/Egr-1 more than that of treatment with cell stressors or ethanol alone. Our pilot data also demonstrate that when compared to normal control subjects, GAPDH levels are more elevated in the prefrontal cortex of subjects with co-morbid depression plus alcoholism than in subjects with either depression or alcoholism alone. In the current application, we propose a novel GAPDHmediated neuronal stress pathway that may involve GAPDH binding to Egr-1. Once inside the nucleus, the GAPDHEgr-1 complex separates, Egr-1 targets the monoamine oxidase B (MAO B) gene, thus increasing the expression of MAO B. MAO B then enzymatically degrades a number of neurotransmitters, producing toxic reactive oxygen (H2O2) and resulting in neuronal cell stress which promotes cell death or apoptosis. We hypothesize that the GAPDH-Egr-1-MAO-B-mediated neuronal stress pathway contributes to the pathogenesis of depression and alcoholism and is more evident in co-morbid depression and alcoholism than in either depression or alcoholism alone. We further hypothesize that the inhibition of the GAPDH-Egr-1-MAO-Bmediated neuronal stress pathway will protect brain cells from harmful stress- and ethanol-induced effects. Our Specific Aims are: (1) to characterize the components active in the GAPDH-Egr-1-MAO-B -mediated neuronal stress pathway by measuring the apoptotic marker (fragmented DNA) and the levels of Egr-1 and MAO B (the downstream targets of GAPDH) in the prefrontal cortex from stressed or ethanol-treated rats as compared to untreated controls; (2) to examine the expression of apoptotic markers (fragmented DNA), GAPDH and its downstream targets in postmortem brain tissue from depressed alcoholic subjects as compared to depressed subjects, alcohol-dependent subjects and normal control subjects; and (3) to disrupt the GAPDH-Egr-1-MAO-B -mediated neuronal stress pathway (using the siRNA) to test the hypothesis that inhibition of GAPDH will reduce the harmful effects of cell stressors and ethanol. These studies are relevant to other CPN projects, because excessive glutamate signaling (Subproject 2) has been reported to trigger the GAPDH-mediated neuronal cell death cascade. The GAPDH-Egr-1-MAO-B pathway may contribute to this death cascade which causes brain cell loss in major depression (Subproject 1). Furthermore, GAPDH affects the genetic regulation of MAO, a key enzyme in degradation of serotonin. Thus, elucidating the GAPDH-Egr- 1-MAO-B -mediated neuronal stress/cell death pathway may provide new insights into serotonin system dysfunction (Subprojects 3 and 4), and might lead to novel therapeutic strategies for co-morbid depression and alcoholism.