Data_Sheet_1_Resistin-Like Molecule α Dysregulates Cardiac Bioenergetics in Neonatal Rat Cardiomyocytes.pdf

Heart (right) failure is the most frequent cause of death in patients with pulmonary arterial hypertension. Although historically, increased right ventricular afterload has been considered the main contributor to right heart failure in such patients, recent evidence has suggested a potential role of load-independent factors. Here, we tested the hypothesis that resistin–like molecule α (RELMα), which has been implicated in the pathogenesis of vascular remodeling in pulmonary artery hypertension, also contributes to cardiac metabolic remodeling, leading to heart failure. Recombinant RELMα (rRELMα) was generated via a Tet-On expression system in the T-REx 293 cell line. Cultured neonatal rat cardiomyocytes were treated with purified rRELMα for 24 h at a dose of 50 nM. Treated cardiomyocytes exhibited decreased mRNA and protein expression of peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) and transcription factors PPARα and ERRα, which regulate mitochondrial fatty acid metabolism, whereas genes that encode for glycolysis-related proteins were significantly upregulated. Cardiomyocytes treated with rRELMα also exhibited a decreased basal respiration, maximal respiration, spare respiratory capacity, ATP-linked OCR, and increased glycolysis, as assessed with a microplate-based cellular respirometry apparatus. Transmission electron microscopy revealed abnormal mitochondrial ultrastructure in cardiomyocytes treated with rRELMα. Our data indicate that RELMα affects cardiac energy metabolism and mitochondrial structure, biogenesis, and function by downregulating the expression of the PGC-1α/PPARα/ERRα axis.

右心衰竭（right heart failure）是肺动脉高压（pulmonary arterial hypertension）患者最常见的死亡原因。尽管长期以来，右心室后负荷升高被认为是此类患者发生右心衰竭的主要诱因，但最新研究证据表明，非负荷依赖因素也可能发挥潜在作用。本研究验证了如下假说：在肺动脉高压（pulmonary artery hypertension）血管重构的发病机制中被证实具有作用的抵抗素样分子α（resistin-like molecule α，RELMα），同样可参与心脏代谢重构，进而诱发心力衰竭。本研究通过Tet-On表达系统（Tet-On expression system）在T-REx 293细胞系（T-REx 293 cell line）中制备了重组RELMα（rRELMα）。采用浓度为50 nM的纯化rRELMα处理培养的新生大鼠心肌细胞，处理时长为24小时。结果显示，经处理的心肌细胞中，调控线粒体脂肪酸代谢的过氧化物酶体增殖物激活受体γ辅激活因子1α（peroxisome proliferator-activated receptor gamma coactivator 1α，PGC-1α）以及转录因子PPARα、ERRα的mRNA和蛋白表达水平均显著下调；而编码糖酵解相关蛋白的基因则明显上调。通过微孔板细胞呼吸测定仪（microplate-based cellular respirometry apparatus）检测发现，经rRELMα处理的心肌细胞其基础呼吸、最大呼吸、储备呼吸能力以及ATP耦联合氧消耗速率（OCR）均出现下降，糖酵解水平则有所升高。透射电子显微镜（transmission electron microscopy）观察结果显示，经rRELMα处理的心肌细胞存在线粒体超微结构异常。本研究数据表明，RELMα可通过下调PGC-1α/PPARα/ERRα信号轴的表达，影响心脏能量代谢以及线粒体的结构、生物发生与功能。