Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States of America.
Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, TX, United States of America.
PLoS Pathog. 2018 May 31;14(5):e1007065. doi: 10.1371/journal.ppat.1007065. eCollection 2018 May.
Chagasic cardiomyopathy is caused by Trypanosoma cruzi infection. Poly(ADP-ribose) polymerase 1 (PARP1) is known for its function in nuclear DNA repair. In this study, we have employed genetic deletion and chemical inhibition approaches to determine the role of PARP1 in maintaining mtDNA dependent mitochondrial function in Chagas disease. Our data show that expression of PARP1 and protein PARylation were increased by >2-fold and >16-fold, respectively, in the cytosolic, nuclear, and mitochondrial fractions of the human cardiac myocytes and the myocardium of wildtype (WT) mice chronically infected with T. cruzi. The nuclear and cytosolic PARP1/PAR did not interfere with the transcription and translation of the components of the mtDNA replisome machinery in infected cardiomyocytes and chagasic murine myocardium. However, PARP1 binding to Polymerase γ and mtDNA in mitochondria were increased, and associated with a loss in mtDNA content, mtDNA-encoded gene expression, and oxidative phosphorylation (OXPHOS) capacity, and an increase in mitochondrial ROS production in cells and heart of WT mice infected with T. cruzi. Subsequently, an increase in oxidative stress, and cardiac collagen deposition, and a decline in LV function was noted in chagasic mice. Genetic deletion of PARP1 or treatment with selective inhibitor of PARP1 (PJ34) improved the mtDNA content, mitochondrial function, and oxidant/antioxidant balance in human cardiomyocytes and chronically infected mice. Further, PARP1 inhibition was beneficial in preserving the cardiac structure and left ventricular function in chagasic mice. We conclude that PARP1 overexpression is associated with a decline in Pol γ-dependent maintenance of mtDNA content, mtDNA-encoded gene expression, and mitochondrial respiratory function, and subsequently contributes to an increase in mtROS and oxidative stress in chagasic myocardium. Inhibition of mitochondrial PARP1/PAR offers a novel therapy in preserving the mitochondrial and LV function in chronic Chagas disease.
克氏锥虫感染引起的恰加斯心肌病。多聚（ADP-核糖）聚合酶 1（PARP1）以其在核 DNA 修复中的功能而闻名。在这项研究中，我们采用基因缺失和化学抑制方法来确定 PARP1 在维持恰加斯病中线粒体 DNA 依赖性线粒体功能中的作用。我们的数据表明，在感染克氏锥虫的人类心肌细胞和野生型（WT）小鼠心肌的细胞质、核质和线粒体部分，PARP1 的表达和蛋白 PAR 化分别增加了>2 倍和>16 倍。核质和细胞质 PARP1/PAR 不干扰感染心肌细胞和恰加斯病鼠心肌中线粒体复制酶机器成分的转录和翻译。然而，PARP1 与聚合酶γ和线粒体中的 mtDNA 结合增加，与 mtDNA 含量、mtDNA 编码基因表达和氧化磷酸化（OXPHOS）能力的丧失以及 WT 小鼠感染 T. cruzi 后细胞和心脏中线粒体 ROS 产生的增加有关。随后，在感染克氏锥虫的小鼠中观察到氧化应激增加、心脏胶原沉积减少和 LV 功能下降。PARP1 的基因缺失或选择性 PARP1 抑制剂（PJ34）的治疗改善了人类心肌细胞和慢性感染小鼠中的 mtDNA 含量、线粒体功能和氧化应激/抗氧化平衡。此外，PARP1 抑制有利于保存感染克氏锥虫的小鼠的心脏结构和左心室功能。我们得出结论，PARP1 过表达与 Pol γ 依赖性 mtDNA 含量、mtDNA 编码基因表达和线粒体呼吸功能的下降有关，并随后导致 mtROS 和氧化应激在恰加斯病心肌中的增加。抑制线粒体 PARP1/PAR 为保护慢性恰加斯病中线粒体和 LV 功能提供了一种新的治疗方法。
