Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi, P.R. China.
J Cell Physiol. 2013 Jun;228(6):1238-48. doi: 10.1002/jcp.24277.
Mitochondrial biogenesis disorders appear to play an essential role in cardiac dysfunction. Acetylcholine as a potential pharmacologic agent exerts cardioprotective effects. However, its direct action on mitochondria biogenesis in acute cardiac damage due to ischemia/reperfusion remains unclear. The present study determined the involvement of mitochondrial biogenesis and function in the cardiopotection of acetylcholine in H9c2 cells subjected to hypoxia/reoxygenation (H/R). Our findings demonstrated that acetylcholine treatment on the beginning of reoxygenation improved cell viability in a concentration-dependent way. Consequently, acetylcholine inhibited the mitochondrial morphological abnormalities and caused a significant increase in mitochondrial density, mass, and mitochondrial DNA (mtDNA) copy number. Accordingly, acetylcholine enhanced ATP synthesis, membrane potentials, and activities of mitochondrial complexes in contrast to H/R alone. Furthermore, acetylcholine stimulated the transcriptional activation and protein expression of peroxisome proliferator-activated receptor co-activator 1 alpha (PGC-1α, the central factor for mitochondrial biogenesis) and its downstream targets including nuclear respiration factors and mitochondrial transcription factor A. In addition, acetylcholine activated phosphorylation of AMP-activated protein kinase (AMPK), which was located upstream of PGC-1α. Atropine (muscarinic receptor antagonist) abolished the favorable effects of acetylcholine on mitochondria. Knockdown of PGC-1α or AMPK by siRNA blocked acetylcholine-induced stimulating effects on mtDNA copy number and against cell injury. In conclusion, we suggested, acetylcholine as a mitochondrial nutrient, protected against the deficient mitochondrial biogenesis and function induced by H/R injury in a cellular model through muscarinic receptor-mediated, AMPK/PGC-1α-associated regulatory program, which may be of significance in elucidating a novel mechanism underlying acetylcholine-induced cardioprotection.
线粒体生物发生障碍似乎在心脏功能障碍中起重要作用。乙酰胆碱作为一种潜在的药物制剂,具有心脏保护作用。然而,其在缺血/再灌注引起的急性心脏损伤中对线粒体生物发生的直接作用尚不清楚。本研究确定了线粒体生物发生和功能在 H9c2 细胞缺氧/复氧(H/R)中乙酰胆碱心脏保护中的作用。我们的研究结果表明,再复氧开始时乙酰胆碱处理以浓度依赖的方式改善细胞活力。因此,乙酰胆碱抑制线粒体形态异常,并导致线粒体密度、质量和线粒体 DNA(mtDNA)拷贝数显著增加。相应地,乙酰胆碱增强了与 H/R 单独作用相比的 ATP 合成、膜电位和线粒体复合物的活性。此外,乙酰胆碱刺激过氧化物酶体增殖物激活受体共激活因子 1α(PGC-1α,线粒体生物发生的核心因子)及其下游靶标,包括核呼吸因子和线粒体转录因子 A 的转录激活和蛋白表达。此外,乙酰胆碱激活了 AMP 激活蛋白激酶(AMPK)的磷酸化,AMPK 位于 PGC-1α 的上游。阿托品(毒蕈碱受体拮抗剂)消除了乙酰胆碱对线粒体的有利影响。PGC-1α 或 AMPK 的 siRNA 敲低阻断了乙酰胆碱诱导的 mtDNA 拷贝数增加和对抗细胞损伤的刺激作用。总之,我们提出,乙酰胆碱作为一种线粒体营养素,通过毒蕈碱受体介导的、与 AMPK/PGC-1α 相关的调节程序,在细胞模型中防止了 H/R 损伤引起的线粒体生物发生和功能缺陷,这可能对阐明乙酰胆碱诱导的心脏保护的新机制具有重要意义。