PPAR-gamma and REVERBs Attenuate Atherosclerosis by Modulating Tregs and Th17 Ce

动脉粥样硬化是一种慢性炎症性疾病，涉及常驻血管壁细胞和浸润免疫细胞之间的复杂相互作用。T细胞稳态的丧失有助于斑块发展和炎症。调节性T细胞（TCLs）通过抑制免疫反应（包括促炎性辅助性T细胞的作用）来抑制动脉粥样硬化的发生和进展 17（Th 17）细胞。我们鉴定了核受体PPARy和REVERBa/B分别在胸主动脉周围Tv 4和Th 17细胞中的表达。我们的基本假设是，动脉粥样硬化病变的发展是由一个促炎基因网络驱动的，该网络可以在转录水平上进行调节。 通过PPARy和REVERBa/B水平。我们的方法是采用互补的功能丧失和药物介导的功能获得小鼠研究，以及全基因组转录组和顺式研究，以确定PPARy和REVERBs在动脉粥样硬化形成中作用的分子机制。在目的1中，我们将采用一种新的Treg特异性PPARy敲除小鼠与PPARy激动剂的组合，以了解PPARy依赖性信号传导在动脉粥样硬化发展过程中内脏脂肪组织驻留的Treg中的作用。在目标2中，我们将确定PPARy的全基因组染色质结合位点，定义PPARy依赖性转录组，并绘制主动脉周围脂肪TTRY的翻译组（Ribo-seq），以确定TTRY中PPARy作用的信号传导途径和分子机制。在目的3中，我们将检查REVERBa/B在动脉粥样硬化形成的背景下减弱促炎性Th 17细胞中的作用。这些REVERB自然地反对RORy，Th 17谱系指定。我们的方法是利用在T细胞中选择性缺失REVERBa和REVERBB的小鼠，与生物学上可获得的REVERB激动剂SR9009组合，以确定REVERB信号传导对Th 17细胞分化的后果以及对动脉粥样硬化的起始和进展的最终影响。同样，在目标4中，我们将通过比较REVERBa和REVERBB的基因组， 广泛的染色质结合位点的REVERB依赖性转录组在Th 17细胞，从而阐明REVERB介导的抑制机制。这些高度整合的目标采用生物化学，分子，遗传学，药理学和生理学方法来阐明免疫抑制性Th 17细胞和促炎性Th 17细胞在这种疾病中的竞争作用。这些免疫细胞群中这些治疗可及的核受体的作用的表征可能导致用于预防和治疗动脉粥样硬化的新型小分子药物的开发。

Atherosclerosis is a chronic inflammatory disease involving a complex interplay between resident vascular wall cells and infiltrating immune cells. Loss of T cell homeostasis contributes to both plaque development and inflammation. Regulatory T cells (Tregs) inhibit atherosclerotic development and progression through suppression of immune responses, including the actions of pro-inflammatory T helper 17 (Th17) cells. We identified the expression of the nuclear receptors PPARy and REVERBa/B in thoracic periaortic Tregs and Th17 cells, respectively. Our underlying hypothesis is that the development of the atherogenic lesion is driven by a pro-inflammatory gene network that can be modulated at the transcriptional level by PPARy and REVERBa/B. Our approach is to employ complementary loss-of-function and drug¿ mediated gain-of-function mouse studies, as well as genome-wide transcriptomic and cistromic studies, to define the molecular mechanisms of PPARy and REVERBs actions in atherogenesis. In Aim 1, we will employ a novel Treg-specific PPARy knockout mouse in combination with PPARy agonists, to understand the role of PPARy-dependent signaling in visceral adipose tissue-resident Tregs during the development of atherosclerosis. In Aim 2 we will determine PPARy's genome-wide chromatin binding sites, define the PPARy-dependent transcriptome, and map the translatome (Ribo-seq) of peri-aortic fat Tregs in order to determine the signaling pathways and molecular mechanisms of PPARy action in Tregs. In Aim 3 we will examine the role of REVERBa/B in attenuating pro-Inflammatory Th17 cells in the context of atherogenesis. These REVERBs naturally oppose RORy, the Th17 lineage specifier. Our approach is to utilize mice with selective deletion of both REVERBa and REVERBB in T cells, in combination with the biologically-available REVERB agonist, SR9009, to determine the consequences of REVERB signaling on the differentiation of Th17 cells and the resultant effects on the initiation and progression of atherosclerosis. Similarly, in Aim 4 we will identify direct and indirect target genes of REVERBa and REVERBB by comparing their genome¿ wide chromatin binding sites to the REVERB-dependent transcriptomes in Th17 cells, thereby shedding light on the mechanisms of REVERB-mediated repression. These highly integrated Aims employ biochemical, molecular, genetic, pharmacologic and physiologic approaches to clarify the competing roles of the immuno¿ suppressive Tregs and the pro-inflammatory Th17 cells in this disease. Characterization of the roles of these therapeutically-accessible nuclear receptors in these immune cell populations may lead to the development of novel small molecule drugs for the prevention and treatment of atherosclerosis.