Role of a novel PGC-1α isoform in gene transcription

过氧化物酶体增殖物激活受体-γ共激活因子1α(pGC-1α)是一种转录共激活因子 对于哺乳动物细胞对不同生理应激的代谢适应至关重要。除了这一点， 在控制细胞新陈代谢中的功能被很好地描述，描述保护作用的报告的数量 抗炎的pGC-1α呈上升趋势。我在这里报告了一种新的应激依赖的促炎因子pGC-1α 我在体外C2C12小鼠成肌细胞和活体小鼠骨骼肌中鉴定出的变异。 我未发表的结果表明，与规范的pgc-1α亚型(也称为 PGC-1α(1))，这种新的72 kDa pGC-1α亚型，我称之为pGC-1α(72)，其典型结构是 缺少C端15个氨基酸。缺失的C-末端序列包含一个9-氨基酸的α 我之前报道的螺旋对于pGC-1α(1)与帽结合蛋白80结合并与 反式激活促肌源性pGC-1α依赖基因。与pGC-1α(1)相比，pGC-1α(72)缺乏 CBP80结合基序(CBM)，如我的数据所示，激活促炎基因的转录。在……里面 我的研究策略的第一个目标是，我建议使用C2C12成肌细胞来充分表征 这个新的pGC-1α(72)亚型，鉴定那些转录因子和rna结合蛋白调节其 在压力下表达，并全面确定它激活的转录网络。 在第二个目标中，我将利用我的发现，对pGC-1αCBM的功能抑制 PGC-1α(72)依赖的趋化因子等促炎趋化因子的表达 CCL2.随着年龄的增长，CCL2血浆水平升高已被认为是重要的危险因素 许多炎症性疾病的致病因素，包括心脏纤维化、动脉粥样硬化和癌症。 从机制上讲，CCL2被发现在单核细胞募集到血液内皮细胞中发挥作用 血管和单核细胞渗入炎症组织。我将培育我们新鉴定的pgc-1αCBMmut Ddystrophin缺陷型Dmdmdx肌肉炎症和早衰小鼠模型的建立及应用 来源的原代成肌细胞以推断PGC-1α(72)表达的功能后果，特别是那些 归因于其缺乏煤层气，归因于炎症。特别是，我将确定pgc-1αCBMmut如何触发 CCL2依赖的单核细胞对内皮细胞的募集，其对心脏组织的渗透，以及 老年小鼠心脏纤维化的发展与性别的关系，即雄性与雌性。 我认为展示pGC-1αCBMmut对心脏纤维化的贡献是一个概念证明。会的 为研究骨骼肌PgC-1α(72)在其他衰老发育中的作用提供了肥沃的基础。 相关的炎症性疾病。我假设理解pGC-1α(72)依赖的基因调控和它的 炎症性疾病发展的后果将促进新疗法的发展， 如合成反义寡核苷酸调控pGC-1Pre-α的剪接。

Peroxisome proliferator-activated receptor gamma co-activator 1α (PGC-1α) is a transcriptional coactivator that is critical for the metabolic adaptation of mammalian cells to diverse physiological stresses. In addition to this well-described function in the control of cell metabolism, the number of reports describing a protective role for PGC-1α against inflammation is on the rise. I report here a novel stress-dependent pro-inflammatory PGC-1α variant that I have identified in vitro in C2C12 mouse myoblasts and in vivo in mouse skeletal muscle. My unpublished results indicate that, compared to the canonical PGC-1α isoform (also known as PGC-1α(1)), the structure of this novel 72-kDa PGC-1α isoform, which I will call PGC-1α(72), is typified by its lack of the C-terminal 15 amino acids. The deleted C-terminal sequence encompasses a 9-amino-acid alpha helix that I previously reported to be essential for PGC-1α(1) to bind to the cap-binding protein (CBP)80 and to transactivate pro-myogenic PGC-1α-dependent genes. In contrast to PGC-1α(1), PGC-1α(72) lacks the CBP80-binding motif (CBM) and, as my data indicate, activates the transcription of pro-inflammatory genes. In the first aim of my research strategy, I propose to use C2C12 myoblasts to fully characterize the sequence of this novel PGC-1α(72) isoform, identify those transcription factors and RNA-binding proteins that regulate its expression in response to stress, and comprehensively determine the transcriptional network that it activates. In the second aim, I will take advantage of my finding that functional inhibition of the PGC-1α CBM phenocopies PGC-1α(72)-dependent expression of pro-inflammatory chemoattractants such as the chemokine CCL2. Elevated CCL2 plasma levels, which are observed with aging, have been recognized as important risk factors for numerous inflammatory diseases, including cardiac fibrosis, atherosclerosis and cancers. Mechanistically, CCL2 has been found to function in monocyte recruitment onto the endothelium of blood vessels and in monocyte infiltration into inflamed tissues. I will breed our newly characterized PGC-1αCBMmut mice with the Dystrophin-deficient Dmdmdx muscle inflammatory and premature aging mouse model and use derived primary myoblasts to infer the functional consequences of PGC-1α(72) expression, in particular those attributable to its lacking the CBM, to inflammation. In particular, I will determine how PGC-1αCBMmut triggers the CCL2-dependent recruitment of monocytes onto endothelial cells, their infiltration into cardiac tissues, and development of cardiac fibrosis in aging mice as a function of sex, i.e. in males vs. females. I view demonstrating the contribution of PGC-1αCBMmut to cardiac fibrosis as a proof of concept. It will provide fertile grounds to study the function of skeletal muscle PGC-1α(72) in the development of other aging- related inflammatory diseases. I hypothesize that understanding PGC-1α(72)-dependent gene regulation and its consequences to the development of inflammatory diseases will facilitate the development of new therapeutics, such as synthetic antisense oligonucleotides regulating splicing of PGC-1α pre-mRNA.