THE ROLES OF PROHIBITINS (PHBS) IN 3T3-L1 ADIPOCYTE DIFFERENTIATION

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。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 项目总结（见说明）： 在过去的20年里，超重和肥胖的人数在美国显着增加。超重或肥胖会增加患高血压和糖尿病等多种疾病的风险。阐明前脂肪细胞增殖、分化和凋亡的机制对于肥胖症的治疗具有重要意义。我们目前的建议将侧重于以下两个长期目标：1）。 表征在脂肪细胞分化期间上调的线粒体蛋白的作用; 2）. 表征了拟南芥素（PHBs）基因的转录调控。 抑肽酶（PHB 1和PHB 2）是两种细胞内分子，它们相互依赖并共同形成高分子量的聚羟基丁酸复合物。我们的初步数据表明，这两个PHB在3 T3-L1前脂肪细胞的脂肪细胞分化过程中显着增加。此外，3 T3-L1脂肪细胞的分化受损后，同时敲低任一聚羟基丁酸酯蛋白siRNAPHB 1或siRNA-PHB 2。这些结果导致了这两种PHB在3 T3-L1脂肪细胞分化中至关重要的假设。基于生物信息学分析，我们在小鼠和人的PHBs启动子中发现了一些推测的Egr-1转录因子结合位点。此外，我们观察到，Egr-1的表达诱导之前，在3 T3-L1脂肪细胞分化过程中的PHBs的增加。此外，脂肪转基因Egr-1小鼠脂肪组织中的PHBs蛋白表达上调。这些结果导致了第二个假设，即Egr-1是3 T3-L1脂肪细胞中PHB上调的关键调节剂。 分化 该提案的两个具体目标是：1）。检验PHB在3 T3-L1脂肪细胞分化中至关重要的假设。“PHBs功能丧失”和“PHBs功能获得”研究将用于此目的; 2）.检验Egr-1在3 T3-L1脂肪细胞分化过程中调节PHB上调的假设。在Egr-1的“功能丧失”和“功能获得”后的PHBs表达分析，以及小鼠PHBs基因的启动子活性分析将在此目的中进行测试。 如果结果支持抑制素在脂肪细胞分化中起关键作用的假设，那么抑制素可能被用作抗肥胖的有效药物靶点。

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. PROJECT SUMMARY (See instructions): In the past 20 years, the number of overweight and obese individuals has increased significantly in the United States. Being overweight or obese increases the risk of the development of many diseases such as hypertension and diabetes. Elucidating the mechanisms of the proliferation, differentiation and apoptosis in preadipocytes will be essential for the development of therapies for obesity. Our current proposal will focus on the following two long-term goals: 1). Characterizing the roles of the upregulated mitochondrial proteins during adipocyte differentiation; 2). Characterizing the transcriptional regulation of the prohibitins (PHBs) genes. Prohibitins (PHB1 and PHB2) are two intracellular molecules that display interdependence and together form a high molecular weight PHB complex. Our preliminary data showed that both of these PHBs were significantly increased during the adipocyte differentiation of 3T3-L1 preadipocytes. Moreover, 3T3-L1 adipocyte differentiation was impaired after the simultaneous knockdown of either PHBs protein by siRNAPHB1 or siRNA-PHB2. These results lead to the hypothesis that both PHBs are critical in 3T3-L1 adipocyte differentiation. Based on the bioinformatics analyses, we found some putative Egr-1 transcription factor binding sites in the mouse and human PHBs promoters. In addition, we observed that Egr-1 expression was induced prior to the increase of PHBs during 3T3-L1 adipocyte differentiation. Furthermore, the expression of PHBs proteins was upregulated in the adipose tissue in Adipose-transgenic Egr-1 mice. These results lead to a second hypothesis that Egr-1 is a critical modulator of PHBs upregulation during 3T3-L1 adipocyte differentiation. Two specific aims in this proposal are: 1). Test the hypothesis that PHBs are critical in 3T3-L1 adipocyte differentiation. "loss-of-PHBs-function" and "gain-of-PHBs-function" studies will be employed in this aim; 2). Test the hypothesis that Egr-1 modulates PHBs upregulation during 3T3-L1 adipocyte differentiation. PHBs expression analyses after "loss-of-function" and "gain-of-function" of Egr-1, and promoter activity analyses for the mouse PHBs genes will be tested in this aim. Prohibitins may be used as effective drug targets against obesity if the results support the hypothesis that prohibitins are critical in fat cell differentiation.