脂肪细胞特异性敲除 HuR 诱导自发性心肌肥厚和纤维化。

Adipocyte-specific deletion of HuR induces spontaneous cardiac hypertrophy and fibrosis.

机构信息

Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio.

Department of Pharmacology & Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio.

出版信息

Am J Physiol Heart Circ Physiol. 2021 Jul 1;321(1):H228-H241. doi: 10.1152/ajpheart.00957.2020. Epub 2021 May 21.

Abstract

Adipose tissue homeostasis plays a central role in cardiovascular physiology, and the presence of thermogenically active brown adipose tissue (BAT) has recently been associated with cardiometabolic health. We have previously shown that adipose tissue-specific deletion of HuR (Adipo-HuR) reduces BAT-mediated adaptive thermogenesis, and the goal of this work was to identify the cardiovascular impacts of Adipo-HuR. We found that Adipo-HuR mice exhibit a hypercontractile phenotype that is accompanied by increased left ventricle wall thickness and hypertrophic gene expression. Furthermore, hearts from Adipo-HuR mice display increased fibrosis via picrosirius red staining and periostin expression. To identify underlying mechanisms, we applied both RNA-seq and weighted gene coexpression network analysis (WGCNA) across both cardiac and adipose tissue to define HuR-dependent changes in gene expression as well as significant relationships between adipose tissue gene expression and cardiac fibrosis. RNA-seq results demonstrated a significant increase in proinflammatory gene expression in both cardiac and subcutaneous white adipose tissue (scWAT) from Adipo-HuR mice that is accompanied by an increase in serum levels of both TNF-α and IL-6. In addition to inflammation-related genes, WGCNA identified a significant enrichment in extracellular vesicle-mediated transport and exosome-associated genes in scWAT, whose expression most significantly associated with the degree of cardiac fibrosis observed in Adipo-HuR mice, implicating these processes as a likely adipose-to-cardiac paracrine mechanism. These results are significant in that they demonstrate the spontaneous onset of cardiovascular pathology in an adipose tissue-specific gene deletion model and contribute to our understanding of how disruptions in adipose tissue homeostasis may mediate cardiovascular disease. The presence of functional brown adipose tissue in humans is known to be associated with cardiovascular health. Here, we show that adipocyte-specific deletion of the RNA binding protein HuR, which we have previously shown to reduce BAT-mediated thermogenesis, is sufficient to mediate a spontaneous development of cardiac hypertrophy and fibrosis. These results may have implications on the mechanisms by which BAT function and adipose tissue homeostasis directly mediate cardiovascular disease.

摘要

脂肪组织稳态在心血管生理学中起着核心作用,最近人们发现具有产热活性的棕色脂肪组织(BAT)与心脏代谢健康有关。我们之前已经表明,脂肪组织特异性敲除 HuR(Adipo-HuR)会减少 BAT 介导的适应性产热,本研究的目的是确定 Adipo-HuR 对心血管的影响。我们发现,Adipo-HuR 小鼠表现出高收缩表型,伴有左心室壁厚度增加和肥厚基因表达增加。此外,Adipo-HuR 小鼠的心脏通过天狼星红染色和骨膜蛋白表达显示出增加的纤维化。为了确定潜在的机制,我们在心脏和脂肪组织中应用 RNA-seq 和加权基因共表达网络分析(WGCNA)来定义 HuR 依赖性基因表达变化,以及脂肪组织基因表达与心脏纤维化之间的显著关系。RNA-seq 结果表明,Adipo-HuR 小鼠心脏和皮下白色脂肪组织(scWAT)中的促炎基因表达显著增加,同时血清中 TNF-α 和 IL-6 的水平也升高。除了与炎症相关的基因外,WGCNA 还确定了 scWAT 中细胞外囊泡介导的运输和外泌体相关基因的显著富集,这些基因的表达与 Adipo-HuR 小鼠观察到的心脏纤维化程度最显著相关,暗示这些过程可能是脂肪组织到心脏的旁分泌机制。这些结果意义重大,因为它们证明了在脂肪组织特异性基因缺失模型中自发性心血管病理的发生,并有助于我们理解脂肪组织稳态的破坏如何介导心血管疾病。人类功能性棕色脂肪组织的存在已知与心血管健康有关。在这里,我们表明,我们之前已经表明减少 BAT 介导的产热的 RNA 结合蛋白 HuR 的脂肪细胞特异性缺失足以介导心脏肥大和纤维化的自发发展。这些结果可能对 BAT 功能和脂肪组织稳态直接介导心血管疾病的机制具有重要意义。

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