Nie Qian, Zhao Jue, Zhang Hongcai, Zhang Delai, Xie Wen
Department of Cardiology, Hospital of Chengdu University of Traditional Chinese Medicine, No. 39 Shi-er-qiao Road, Chengdu, 610072 Sichuan China.
3 Biotech. 2021 Apr;11(4):185. doi: 10.1007/s13205-021-02719-6. Epub 2021 Mar 22.
The present work aimed to identify the roles of WWP2 (an E3 ubiquitin-protein ligase) and protein phosphatase 1 regulatory subunit 3A (PPP1R3A) in different pathological stages of cardiac arrhythmia development. Leptin-deficient mice (C57BLKS-Lepr/Lepr) were used for the development of initial and severe stages of cardiac arrhythmia. Histology, ECG, immunohistochemistry and Western blotting were used to analyse cardiac arrhythmia, WWP2 and PPP1R3A expression. Histopathological studies of 4-month-old mice showed cardiac degeneration, cellular lesions, and swollen tissue structure with loss of tissue elasticity, indicative of the initial condition of cardiac arrhythmia. The leptin-deficient 7-month-old mice showed cardiac tissue hardening with increased secretion of extracellular matrix. The development of initial- and severe-cardiac arrhythmia was further evident with electrocardiogram studies, which showed more PP interval variations as the disease progressed. At the molecular level, WWP2 showed marginal upregulation in the initial stages of arrhythmia and was predominantly expressed within nuclei. WWP2 was overexpressed 6.6-fold in the severe stage of cardiac arrhythmia and was spread throughout the tissue layer. Interestingly, PPP1R3A was significantly overexpressed in initial cardiac arrhythmia conditions, but was downregulated and restricted to more nuclear expression in advanced cardiac arrhythmia. Silencing of PPP1R3A, enhances the expression of WWP2 to 5.3-fold in initial stages, but remarkable variation not observed in advanced cardiac arrhythmia conditions. Our results suggest that PPP1R3A had a control over WWP2 in the initial stages of cardiac arrhythmia. In particular, PPP1R3A overexpression implies its potential protective effect in initial cardiac arrhythmia stages.
本研究旨在确定WWP2（一种E3泛素蛋白连接酶）和蛋白磷酸酶1调节亚基3A（PPP1R3A）在心律失常发展的不同病理阶段所起的作用。利用瘦素缺乏小鼠（C57BLKS-Lepr/Lepr）建立心律失常的初始阶段和严重阶段。采用组织学、心电图、免疫组织化学和蛋白质印迹法分析心律失常、WWP2和PPP1R3A的表达。对4月龄小鼠的组织病理学研究显示心脏退变、细胞损伤以及组织结构肿胀且组织弹性丧失，这表明处于心律失常的初始状态。7月龄瘦素缺乏小鼠表现出心脏组织硬化，细胞外基质分泌增加。心电图研究进一步证实了初始和严重心律失常的发展，结果显示随着疾病进展，PP间期变化更多。在分子水平上，WWP2在心律失常初始阶段有轻微上调，且主要在细胞核内表达。在心律失常严重阶段，WWP2过表达6.6倍，且遍布整个组织层。有趣的是，PPP1R3A在心律失常初始阶段显著过表达，但在晚期心律失常中表达下调且局限于更多的细胞核表达。沉默PPP1R3A可使初始阶段的WWP2表达增加至5.3倍，但在晚期心律失常情况下未观察到明显变化。我们的结果表明，在心律失常初始阶段，PPP1R3A对WWP2有调控作用。特别是，PPP1R3A的过表达意味着它在心律失常初始阶段可能具有保护作用。
