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，尽管 他汀类药物的广泛成功。全基因组关联研究已经确定了数百个基因组 与人类血浆脂蛋白特征和冠状动脉疾病(CAD)显著相关的基因座，许多 其中包含以前与代谢性疾病发病机制无关的基因。这些基因座可能代表 新的疾病生物学和心血管疾病治疗干预的新途径。8q24基因座，含有该基因 Tribble-1(TRIB1)是仅有的两个与所有血脂性状(总胆固醇、低密度脂蛋白、高密度脂蛋白胆固醇、 甘油三酯(TG)和冠心病，但对支配这些联系的机制知之甚少。 有趣的是，TRIB1也与血浆脂联素水平显著相关，这表明TRIB1具有 在脂肪生物学中扮演的角色。我们在这里提供了脂肪特异性Trib1(Trib1_Asko)基因敲除的小鼠的数据 能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，这一发现的部分原因是肝脏胆固醇合成减少。因此，它看起来 脂肪Trib1通过肝脏和脂肪之间的串扰作用影响肝脏的脂质代谢。这是一致的 由于观察到Trib1_Asko小鼠改变了脂肪因子的分泌，但之前的工作表明 在Trib1_Asko小鼠中观察到的胆固醇降低可能不依赖于脂联素。Trib1如何发挥作用 脂肪因子的分泌是未知的，尽管已经建立了TRIB1和转录的关系 因子C/EBP本身是脂肪生成的重要调节因子，我们的初步数据表明， 脂肪细胞中的Trib1不依赖于C/EBP。最后，Trib1_Asko小鼠的血脂变化 提示脂肪TRIB1调节血浆脂蛋白代谢，从而推断GWASSNPs 近TRIB1可能通过改变基因表达而影响脂肪特异性TRIB1的功能。 目前，对TRIB1在脂肪中的表达调控和常见变异的影响知之甚少。 在这条规定上。在这项建议中，我概述了一种确定血脂变化原因的策略。 Trib1_Asko小鼠，脂肪细胞TRIB1的功能，以及非编码变异NEAR的脂肪特异性效应 TRIB1.我将使用转基因动物模型，体外和体外细胞培养，实现这些目标， AAV介导的体细胞基因操作、CRISPR/Cas9的基因组编辑和人类诱导多能性 干细胞。TRIB1仍然是从血脂和CAD GWAS研究中产生的最有趣的基因之一， 考虑到它与之相关的一系列特征。这项提案中概述的研究有望阐明小说 该蛋白在脂肪中的功能，以及对脂肪调节肝脂蛋白代谢的作用。这些 研究将进一步加深我们对冠心病和血脂异常发病机制的理解，同时揭示 针对TRIB1和脂肪组织的治疗进展。

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.