The Institute of Cardiovascular Diseases & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Tianjin University & Chinese Academy of Medical Sciences, Tianjin 300457, China.
Department of Electrophysiology, TEDA International Cardiovascular Hospital, Tianjin University & Chinese Academy of Medical Sciences, Tianjin 300457, China.
Int J Biol Macromol. 2023 Jul 1;242(Pt 4):125151. doi: 10.1016/j.ijbiomac.2023.125151. Epub 2023 Jun 1.
Protein post-translational modifications (PTMs) are important regulators of protein functions and produce proteome complexity. SIRT1 has NAD-dependent deacylation of acyl-lysine residues. The present study aimed to explore the correlation between lysine crotonylation (Kcr) on cardiac function and rhythm in Sirt1 cardiac-specific knockout (ScKO) mice and related mechanism. Quantitative proteomics and bioinformatics analysis of Kcr were performed in the heart tissue of ScKO mice established with a tamoxifen-inducible Cre-loxP system. The expression and enzyme activity of crotonylated protein were assessed by western blot, co-immunoprecipitation, and cell biology experiment. Echocardiography and electrophysiology were performed to investigate the influence of decrotonylation on cardiac function and rhythm in ScKO mice. The Kcr of SERCA2a was significantly increased on Lys120 (1.973 folds). The activity of SERCA2a decreased due to lower binding energy of crotonylated SERCA2a and ATP. Changes in expression of PPAR-related proteins suggest abnormal energy metabolism in the heart. ScKO mice had cardiac hypertrophy, impaired cardiac function, and abnormal ultrastructure and electrophysiological activities. We conclude that knockout of SIRT1 alters the ultrastructure of cardiac myocytes, induces cardiac hypertrophy and dysfunction, causes arrhythmia, and changes energy metabolism by regulating Kcr of SERCA2a. These findings provide new insight into the role of PTMs in heart diseases.
蛋白质翻译后修饰（PTMs）是蛋白质功能的重要调节因子，产生蛋白质组的复杂性。SIRT1 具有 NAD 依赖性酰基辅酶 A 赖氨酸残基去乙酰化作用。本研究旨在探讨 Sirt1 心脏特异性敲除（ScKO）小鼠心脏功能和节律中赖氨酸巴豆酰化（Kcr）的相关性及其相关机制。采用他莫昔芬诱导的 Cre-loxP 系统建立 ScKO 小鼠模型，对心脏组织中的 Kcr 进行定量蛋白质组学和生物信息学分析。通过 Western blot、共免疫沉淀和细胞生物学实验评估巴豆酰化蛋白的表达和酶活性。通过超声心动图和电生理学研究去巴豆酰化对 ScKO 小鼠心脏功能和节律的影响。SERCA2a 的 Lys120 上的 Kcr 明显增加（1.973 倍）。由于巴豆酰化 SERCA2a 与 ATP 的结合能降低，SERCA2a 的活性降低。与 PPAR 相关蛋白的表达变化表明心脏中存在异常能量代谢。ScKO 小鼠出现心肌细胞超微结构改变、心脏肥厚、心功能受损、心律失常以及能量代谢改变。我们得出结论，SIRT1 的敲除通过调节 SERCA2a 的 Kcr 改变心肌细胞的超微结构，导致心脏肥厚和功能障碍，引起心律失常，并改变能量代谢。这些发现为 PTMs 在心脏病中的作用提供了新的见解。
