Ninh Van K, Barlow Melissa, Aydin Sidar, Brand Cameron Servetus, Yu Justin, Smith Jeffrey, Francisco Jamie, Daneman Richard, King Kevin Robert, Miyamoto Shigeki, Del Re Dominic P, Brown Joan Heller
Department of Pharmacology, University of California San Diego School of Medicine, La Jolla, CA 92093.
Department of Medicine, University of California San Diego School of Medicine, La Jolla, CA 92093.
Am J Physiol Heart Circ Physiol. 2025 Jul 10. doi: 10.1152/ajpheart.00799.2024.
Cardiomyocyte signaling through the transcriptional co-activator Yes-associated protein (YAP) has been shown to protect the myocardium against ischemic or mechanical stress. Inflammatory responses initiated in cardiomyocytes play a major role in development of cardiac dysfunction. We tested the relationship between YAP and inflammatory gene expression using cardiomyocyte specific YAP-KO mice. WT and KO mice were infused with Angiotensin II (AngII) at 1.5 μg/kg/min and sacrificed 24 hrs or 3 days post infusion. YAP deletion markedly enhanced AngII-induced mRNA expression of pro-inflammatory cytokines and chemokines, a response that occurred selectively within cardiomyocytes. Hearts from YAP-KO mice also had increased F4/80, CD68, and Col1 staining. Single nuclei RNA-sequencing (snRNA-seq) of WT and YAP-KO hearts showed significant upregulation of pro-inflammatory cytokines and of a range of genes including those in the cJun family, CamKIIδ and Tlr4. Isolated cardiomyocytes transfected with YAP siRNA or a constitutively active YAP mutant showed respectively enhanced and decreased cJun, CamkIIδ, and Tlr4 mRNA gene expression. HOMER motif enrichment analysis of differentially expressed genes from the snRNA-seq data revealed that most highly upregulated transcripts in YAP-KO vs WT hearts were enriched in MEF2 binding sites. Western blot analysis of hearts from YAP-KO mice treated with AngII showed increased MEF2C protein compared to WT hearts. MEF2C siRNA transfection diminished the potentiation of gene expression by siYAP in isolated cardiomyocytes, implicating MEF2 as a downstream YAP target. Our findings indicate that activation of cardiomyocyte YAP serves, in part, to repress MEF2 regulated genes and restrain cardiomyocyte inflammation.
已证明心肌细胞通过转录共激活因子Yes相关蛋白（YAP）发出的信号可保护心肌免受缺血或机械应激。心肌细胞中引发的炎症反应在心脏功能障碍的发展中起主要作用。我们使用心肌细胞特异性YAP基因敲除小鼠测试了YAP与炎症基因表达之间的关系。将野生型（WT）和基因敲除（KO）小鼠以1.5μg/ kg / min的速度注入血管紧张素II（AngII），并在注入后24小时或3天处死。YAP缺失显著增强了AngII诱导的促炎细胞因子和趋化因子的mRNA表达，这种反应选择性地发生在心肌细胞内。来自YAP-KO小鼠的心脏中F4/80、CD68和Col1染色也增加。对WT和YAP-KO心脏进行单核RNA测序（snRNA-seq）显示促炎细胞因子以及包括cJun家族、CamKIIδ和Tlr4在内的一系列基因显著上调。用YAP小干扰RNA（siRNA）或组成型活性YAP突变体转染的分离心肌细胞分别显示cJun、CamkIIδ和Tlr4 mRNA基因表达增强和降低。对snRNA-seq数据中差异表达基因的HOMER基序富集分析表明，与WT心脏相比，YAP-KO心脏中上调程度最高的转录本富含MEF2结合位点。对用AngII处理的YAP-KO小鼠心脏进行蛋白质免疫印迹分析显示，与WT心脏相比，MEF2C蛋白增加。MEF2C siRNA转染减少了分离心肌细胞中siYAP对基因表达的增强作用，表明MEF2是YAP的下游靶点。我们的研究结果表明，心肌细胞YAP的激活部分作用是抑制MEF2调控的基因并抑制心肌细胞炎症。
