Table_10_PERM1 regulates energy metabolism in the heart via ERRα/PGC−1α axis.XLSX

AimsPERM1 is a striated muscle-specific regulator of mitochondrial bioenergetics. We previously demonstrated that PERM1 is downregulated in the failing heart and that PERM1 positively regulates metabolic genes known as targets of the transcription factor ERRα and its coactivator PGC-1α in cultured cardiomyocytes. The aims of this study were to determine the effect of loss of PERM1 on cardiac function and energetics using newly generated Perm1-knockout (Perm1–/–) mice and to investigate the molecular mechanisms of its transcriptional control.Methods and resultsEchocardiography showed that ejection fraction and fractional shortening were lower in Perm1–/– mice than in wild-type mice (both p < 0.05), and the phosphocreatine-to-ATP ratio was decreased in Perm1–/– hearts (p < 0.05), indicating reduced contractile function and energy reserves of the heart. Integrated proteomic and metabolomic analyses revealed downregulation of oxidative phosphorylation and upregulation of glycolysis and polyol pathways in Perm1–/– hearts. To examine whether PERM1 regulates energy metabolism through ERRα, we performed co-immunoprecipitation assays, which showed that PERM1 bound to ERRα in cardiomyocytes and the mouse heart. DNA binding and reporter gene assays showed that PERM1 was localized to and activated the ERR target promoters partially through ERRα. Mass spectrometry-based screening in cardiomyocytes identified BAG6 and KANK2 as potential PERM1’s binding partners in transcriptional regulation. Mammalian one-hybrid assay, in which PERM1 was fused to Gal4 DNA binding domain, showed that the recruitment of PERM1 to a gene promoter was sufficient to activate transcription, which was blunted by silencing of either PGC-1α, BAG6, or KANK2.ConclusionThis study demonstrates that PERM1 is an essential regulator of cardiac energetics and function and that PERM1 is a novel transcriptional coactivator in the ERRα/PGC-1α axis that functionally interacts with BAG6 and KANK2.

AimsPERM1 为一种特定于横纹肌的线粒体生物能量学调节因子。我们先前证明，在心力衰竭的心脏中 PERM1 表达下调，并且 PERM1 可正向调控被称为转录因子 ERRα 及其共激活因子 PGC-1α 的靶点代谢基因，在培养的心肌细胞中。本研究旨在通过使用新近生成的 Perm1 敲除（Perm1–/–）小鼠，确定 PERM1 失活对心脏功能和能量代谢的影响，并探讨其转录调控的分子机制。方法与结果：超声心动图显示，与野生型小鼠相比，Perm1–/– 小鼠的射血分数和缩短分数均降低（均 p < 0.05），且 Perm1–/– 心脏中磷酸肌酸与 ATP 的比例降低（p < 0.05），这表明心脏收缩功能和能量储备减弱。整合蛋白质组学和代谢组学分析揭示了 Perm1–/– 心脏中氧化磷酸化下调，糖酵解和多元醇途径上调。为检验 PERM1 是否通过 ERRα 调节能量代谢，我们进行了共免疫沉淀实验，结果显示 PERM1 与心肌细胞和鼠心脏中的 ERRα 结合。DNA 结合和报告基因实验表明，PERM1 通过 ERRα 部分定位于并激活 ERR 靶基因启动子。基于质谱的筛选在心肌细胞中鉴定了 BAG6 和 KANK2 作为 PERM1 转录调控的潜在结合伙伴。哺乳动物单杂交实验，其中 PERM1 与 Gal4 DNA 结合域融合，显示 PERM1 招募至基因启动子足以激活转录，这一过程可通过沉默 PGC-1α、BAG6 或 KANK2 而被抑制。结论：本研究证明，PERM1 是心脏能量和功能的重要调节因子，并且 PERM1 是 ERRα/PGC-1α 轴上的新型转录共激活因子，在功能上与 BAG6 和 KANK2 相互作用。