Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan 430030, China.
Department of Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Mitochondrion. 2021 Sep;60:129-141. doi: 10.1016/j.mito.2021.08.005. Epub 2021 Aug 8.
ATP11p and ATP12p are two nuclear-encoded mitochondrial chaperone proteins required for assembling the F1Fo-ATP synthase F1 sector. ATPAF1 and ATPAF2 are the mammalian homologs of ATP11p and ATP12p. However, the biochemical and physiological relevance of ATPAF1 and ATPAF2 in animal tissues with high energy-dependence remains unclear. To explore the in vivo role of ATP assembly and the effects of ATP synthase deficiency in animals, we have generated knockout (KO) mouse models of these assembly factors using CRISPR/Cas9 technology. While the Atpaf2-KO mice were embryonically lethal, Atpaf1-KO mice grew to adulthood but with smaller body sizes and elevated blood lactate later in life. We specifically investigated how ATPAF1 deficiency may affect ATP synthase biogenesis and mitochondrial respiration in the mouse heart, an organ highly energy-dependent. Western blots and Blue-Native electrophoresis (BN-PAGE) demonstrated a decreased F1 content and ATP synthase dimers in the Atpaf1-KO heart. Mitochondria from ATPAF1-deficient hearts showed ultrastructural abnormalities with condensed degenerated mitochondria, loss of cristae, and impaired respiratory capacity. ATP synthase deficiency also leads to impaired autophagy and mitochondrial dynamic. Consequently, decreased cardiac function was exhibited in adult Atpaf1-KO mice. The results provide strong support that ATPAF1 is essential for ATP synthase assembly and mitochondrial oxidative phosphorylation, thus playing a crucial role in maintaining cardiac structure and function in animals.
ATP11p 和 ATP12p 是两种核编码的线粒体伴侣蛋白，对于组装 F1Fo-ATP 合酶 F1 部分是必需的。ATPAF1 和 ATPAF2 是 ATP11p 和 ATP12p 的哺乳动物同源物。然而，在能量依赖性高的动物组织中，ATPAF1 和 ATPAF2 的生化和生理相关性仍不清楚。为了探索 ATP 组装的体内作用以及 ATP 合酶缺乏对动物的影响，我们使用 CRISPR/Cas9 技术生成了这些组装因子的敲除 (KO) 小鼠模型。虽然 Atpaf2-KO 小鼠在胚胎期是致死的，但 Atpaf1-KO 小鼠能够成年，但体型较小，生命后期血液中的乳酸水平升高。我们特别研究了 ATPAF1 缺乏如何影响小鼠心脏中的 ATP 合酶生物发生和线粒体呼吸，心脏是一个高度依赖能量的器官。Western blot 和 Blue-Native 电泳 (BN-PAGE) 表明，Atpaf1-KO 心脏中的 F1 含量和 ATP 合酶二聚体减少。ATP 合酶缺陷的心脏线粒体显示出超微结构异常，线粒体浓缩退化，嵴丢失，呼吸能力受损。ATP 合酶缺乏还会导致自噬和线粒体动态受损。因此，成年 Atpaf1-KO 小鼠的心脏功能下降。这些结果有力地支持了 ATPAF1 对于 ATP 合酶组装和线粒体氧化磷酸化是必需的，因此在维持动物心脏结构和功能方面起着至关重要的作用。
