Regulation of lipoprotein metabolism by adipose-specific Tribbles-1

心血管疾病（CVD）仍然是西方世界死亡的主要原因， 他汀类药物的广泛成功。全基因组关联研究（GWAS）已经确定了数百个基因组 基因座与人类血浆脂蛋白性状和冠状动脉疾病（CAD）显著相关，许多 其中含有先前不涉及代谢疾病发病机理的基因。这些位点可能代表了 新的疾病生物学和CVD治疗干预的新途径。8 q24基因座，携带基因 Tribbles-1（TRIB 1）是仅有的两个与所有血浆脂质性状（总胆固醇、LDL-C、HDL C、HDL C）相关的基因座之一， 甘油三酯（TG））和CAD，但很少有人知道这些协会的机制。 有趣的是，TRIB 1也与血浆脂联素水平显著相关，表明TRIB 1与血浆脂联素水平相关。 在脂肪生物学中的作用。我们在这里提供的数据表明，脂肪特异性敲除Trib 1（Trib1_ASKO）的小鼠 降低血浆胆固醇和甘油三酯，增加循环脂联素。初步 研究表明，这一发现部分是由于肝胆固醇合成减少。因此， 脂肪Trib 1通过肝脏和脂肪之间的串扰影响肝脏脂质代谢。这是一致 观察到Trib1_ASKO小鼠改变了脂肪因子分泌，但先前的工作表明， 在Trib1_ASKO小鼠中观察到的胆固醇降低可能不依赖于脂联素。Trib 1的影响 脂肪因子分泌是未知的，尽管TRIB 1和转录之间的关系已经建立， 虽然C/EBP因子本身是脂肪形成的重要调节因子，但我们的初步数据表明， Trib 1在脂肪细胞中是C/EBP非依赖性的。最后，Trib1_ASKO小鼠中改变的血浆脂质谱 表明脂肪TRIB 1调节血浆脂蛋白代谢，因此GWAS SNPs TRIB 1附近的突变可能会影响脂肪特异性TRIB 1的功能，可能是通过改变基因表达。 目前，关于TRIB 1在脂肪中的表达调控以及常见变异的影响知之甚少 在这个规定上。在这个建议中，我概述了一个战略，以确定改变血浆脂质的原因， Trib1_ASKO小鼠，脂肪细胞TRIB 1的功能，以及非编码变异的脂肪特异性效应， TRIB 1.我将使用转基因动物模型、体外和离体细胞培养来实现这些目标， AAV介导的体细胞基因操作，CRISPR/Cas9基因组编辑，以及人诱导多能 干细胞TRIB 1仍然是血浆脂质和CAD GWAS研究中最有趣的基因之一， 考虑到它所关联的一系列特征。该提案中概述的研究有望阐明新的 这种蛋白质在脂肪中的功能，以及脂肪在调节肝脂蛋白代谢中的功能。这些 这些研究将进一步加深我们对CAD和血脂异常发病机制的理解，同时揭示治疗冠心病的新途径。 针对TRIB 1和脂肪组织的治疗开发。

Cardiovascular disease (CVD) remains the leading cause of mortality in the western world despite the widespread success of statins. Genome-wide association studies (GWAS) have identified hundreds of genomic loci as significantly associated with plasma lipoprotein traits and coronary artery disease (CAD) in humans, many of which contain genes not previously implicated in metabolic disease pathogenesis. These loci could represent novel disease biology and new avenues for therapeutic intervention in CVD. The 8q24 locus, harboring the gene Tribbles-1 (TRIB1), is one of only two loci to associate with all plasma lipid traits (total cholesterol, LDL-C, HDLC, triglycerides (TG)) and CAD, yet little is known about the mechanisms governing those associations. Interestingly, TRIB1 significantly associates with plasma adiponectin levels as well, suggesting that TRIB1 has a role in adipose biology. We present here data that mice with adipose-specific knockout of Trib1 (Trib1_ASKO) have decreased plasma cholesterol and triglycerides, and increased circulating adiponectin. Preliminary investigations suggest that this finding is due in part to reduced hepatic cholesterol synthesis. Thus, it appears that adipose Trib1 affects hepatic lipid metabolism via crosstalk between the liver and adipose. This is consistent with the observation that Trib1_ASKO mice have altered adipokine secretion, yet previous work suggests that the cholesterol reduction observed in the Trib1_ASKO mice is likely adiponectin independent. How Trib1 effects adipokine secretion is unknown, and despite the established relationship between TRIB1 and the transcription factor C/EBP itself an important regulator of adipogenesis, our preliminary data suggests that the effects of Trib1 in the adipocyte are C/EBP-independent. Finally, the altered plasma lipid profile in the Trib1_ASKO mice suggests that adipose TRIB1 regulates plasma lipoprotein metabolism, and thus it follows that the GWAS SNPs near TRIB1 likely affect the function of adipose-specific TRIB1, presumably through altered gene expression. Currently, little is known about the regulation of TRIB1 expression in adipose and the effects of common variation on this regulation. In this proposal, I outline a strategy for determining the cause of altered plasma lipids in Trib1_ASKO mice, the function of adipocyte TRIB1, and the adipose-specific effect of non-coding variation near TRIB1. I will accomplish these goals using genetically modified animal models, in vitro and ex vivo cell culture, AAV-mediated somatic gene manipulation, genome editing with CRISPR/Cas9, and human induced-pluripotent stem cells. TRIB1 remains one of the most interesting genes to arise from plasma lipid and CAD GWAS studies, given the constellation of traits it associates with. The studies outlined in this proposal promise to elucidate novel functions of both this protein in adipose, and for adipose in regulating hepatic lipoprotein metabolism. These studies will further our understanding of CAD and dyslipidemia pathogenesis while unveiling novel avenues for therapeutic development targeting TRIB1 and adipose tissue.