Genetic regulators of vascular smooth muscle thermogenic differentiation

血管平滑肌产热分化的遗传调节因子

• 批准号: 10521900
• 负责人: MATTHEW D LYNES
• 金额: $ 21.98万
• 依托单位: MAINEHEALTH
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-11-05 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10521900
• 关键词: Genetic; regulators; vascular; smooth; muscle

Obesity and metabolic syndrome are major public health burdens and occur when fat mass increases, leading to dysfunction in adipose tissue. Obesity is negatively associated with the presence of thermogenic brown adipose tissue (BAT), which can be detected in humans and mice exposed to cold temperatures by an increased level of the circulating lipokine 12,13-diHOME. The major cell type in adipose tissue is the adipocyte, and adipocytes that express Uncoupling protein 1 (Ucp1) are termed brown, beige, or recruitable thermogenic adipocytes. Thermogenic adipocytes can arise from two distinct lineages; the canonical lineage derived from mesenchymal preadipocytes that express platelet derived growth factor receptor alpha (Pdgfa), or a newly identified vascular smooth muscle (VSM) lineage that are recruited by cold challenge and are characterized bythe expression of Transient receptor potential cation channel subfamily V member 1 (Trpv1). Importantly, cells from the Trpv1+ VSM lineage express more UCP1 than other adipocytes. 12,13-diHOME is a putative lig and for Trpv1, however whether 12,13-diHOME drives the recruitment of thermogenic adipocytes by activating an adipogenic program is unknown. We propose the novel hypothesis that 12,13-diHOME activates Trpv1+ VSM thermogenic adipocyte precursor cells by signaling through Peroxisome proliferator-activated receptor alpha(Ppara), which has been reported to be downstream of Trpv1, to activate an adipogenic program that is normally suppressed in these cells. To test this hypothesis, we aim: 1) to determine the signaling pathway driving Trpv1+ VSM derived thermogenic adipogenesis; and 2) to identify the genes that suppress the adipogenic differentiation of Trpv1+ vascular smooth muscle cells. We will utilize a Trpv1 lineage tracing mouse model to track the contribution of Trpv1+ VSM cells to thermogenic adipocytes. In the first aim, we will treat these mice with 12,13 diHOME in combination with gain- and loss-of-function approaches to manipulate Ppara signaling and quantify the frequency of thermogenic adipocytes from the Trpv1+ VSM lineage. In the second aim, we will take an unbiased approach to assess the transcriptomic profile of thermogenic adipocytes from the Trpv1+ lineage and compare it to cells from the canonical lineage of adipocytes. This will be followed by in vivo CRISPR screening to systematically measure the effects of genetic loss-of-function for all mouse genes on Trpv1+ VSM adipogenesis. This project will be strongly supported by the COBRE Physiology Core (for cellular bioenergetics), the Histopathology and Microscopy Core (for tissue analysis and confocal microscopy) and the Proteomics and Lipidomics Core (lipid and protein profiling). This innovative project is led by a new junior investigator, Dr. Matthew Lynes, who will be supported by outstanding expert mentors in the fields of perivascular adipose tissue (Lucy Liaw PhD), adipose tissue development (Patrick Seale PhD), and thermogenic fat (Shingo Kajiumura PhD). Determining the positive and negative regulators of Trpv1+ VSM thermogenic adipogenesis will provide new therapeutic strategies to treat obesity and metabolic syndrome.

肥胖和代谢综合征是主要的公共健康负担，当脂肪质量增加，导致脂肪组织功能障碍时就会发生。肥胖与致热棕色脂肪组织(BAT)的存在呈负相关，在暴露于寒冷环境中的人类和小鼠中，可以通过循环脂因子12，13-diHOME水平的增加来检测到BAT。脂肪组织中的主要细胞类型是脂肪细胞，表达解偶联蛋白1(Ucp1)的脂肪细胞被称为棕色、米色或可招募的生热脂肪细胞。生热脂肪细胞可起源于两种不同的谱系：表达血小板衍生生长因子受体α(PDGFA)的间充质前体脂肪细胞的典型谱系，或新发现的血管平滑肌(VSM)谱系，其特征是瞬时受体潜能阳离子通道亚家族V成员1(TRPV1)的表达。重要的是，来自TRPV1+VSM谱系的细胞比其他脂肪细胞表达更多的UCP1。12，13-diHOME可能是TRPV1的LIG，然而，12，13-diHOME是否通过激活成脂程序来驱动生热脂肪细胞的募集尚不清楚。我们提出了一个新的假设，即12，13-diHOME通过激活TRPV1下游的过氧化体增殖物激活受体α(Ppara)信号来激活TRPV1+VSM致热脂肪细胞前体细胞，从而激活通常在这些细胞中被抑制的成脂程序。为了验证这一假说，我们的目标是：1)确定驱动TRPV1+VSM热源性成脂的信号通路；2)鉴定抑制TRPV1+血管平滑肌细胞成脂分化的基因。我们将利用TRPV1谱系追踪小鼠模型来追踪TRPV1+VSM细胞对生热脂肪细胞的贡献。在第一个目标中，我们将用12，13diHOME结合功能获得和丧失的方法来处理这些小鼠，以操纵Ppara信号并量化来自TRPV1+VSM谱系的生热脂肪细胞的频率。在第二个目标中，我们将采取一种公正的方法来评估来自TRPV1+系的生热脂肪细胞的转录图谱，并将其与来自典型脂肪细胞系的细胞进行比较。随后将进行体内CRISPR筛查，以系统地测量所有小鼠基因的遗传功能丧失对TRPV1+VSM脂肪生成的影响。该项目将得到Cobre生理学核心(细胞生物能量学)、组织病理学和显微镜核心(组织分析和共聚焦显微镜)以及蛋白质组学和脂质组学核心(脂质和蛋白质图谱)的大力支持。这一创新项目由一位新的初级研究员Matthew Lynes博士领导，他将得到血管周围脂肪组织(Lucy Liw PhD)、脂肪组织开发(Patrick Seale PhD)和生热脂肪(Shingo Kajiumura PhD)领域的杰出专家导师的支持。确定TRPV1+VSM的正负调控因子将为肥胖和代谢综合征的治疗提供新的治疗策略。