Department of Pathology, School of Basic Medical Sciences, Shanxi Medical University, Taiyuan 030001, China.
Laboratory of Morphology, School of Basic Medical Sciences, Shanxi Medical University, Taiyuan 030001, China.
Acta Biochim Biophys Sin (Shanghai). 2019 Sep 6;51(10):1016-1025. doi: 10.1093/abbs/gmz089.
Autophagy reduction has been confirmed as an important mechanism in apoptosis induction. Our previous study showed that decreased autophagy induced by β1-adrenoceptor autoantibodies (β1-AAs) enhanced cardiomyocyte apoptosis and contributed to heart failure progression. Endoplasmic reticulum stress (ERS) is known to be an important mechanism in intracellular homeostasis and is closely related to autophagy. However, ERS in β1-AA-induced autophagy dysfunction of cardiomyocytes remains unclear. In this study, we used an active immunization rat model and H9c2 cardiomyocytes to study the role of ERS in β1-AA-induced autophagy. Results showed that prolonged action of β1-AAs significantly reduced the autophagy of myocardial tissues and H9c2 cardiomyocytes, and ERS and its related apoptotic pathways were significantly activated. Moreover, mRFP-GFP-LC3 double-labeled adenoviruses were used to detect cardiomyocyte autophagic flux to confirm that β1-AAs caused a significant decrease in autophagic flux in H9c2 cardiomyocytes. The ERS inhibitor, 4-phenylbutyrate (4-PBA), partially attenuated the β1-AA-induced reduction of cardiomyocyte autophagy, consistent with the effect of the mammalian target of rapamycin inhibitor rapamycin (Rapa). Compared to the pretreatment with 4-PBA or Rapa alone, pretreatment with the combination of 4-PBA and Rapa had a greater effect on attenuating the β1-AA-induced decrease in autophagy and β1-AA-induced apoptosis in cardiomyocytes. This study provides an experimental basis for the role of β1-AAs in the homeostatic maintenance of cardiomyocytes in patients with heart failure with respect to autophagy and ERS.
自噬减少已被证实是细胞凋亡诱导的重要机制。我们之前的研究表明，β1 肾上腺素能受体自身抗体（β1-AAs）引起的自噬减少增强了心肌细胞凋亡，并促进心力衰竭进展。内质网应激（ERS）是细胞内稳态的重要机制，与自噬密切相关。然而，β1-AA 诱导的心肌细胞自噬功能障碍中的 ERS 尚不清楚。在这项研究中，我们使用主动免疫大鼠模型和 H9c2 心肌细胞来研究 ERS 在β1-AA 诱导的自噬中的作用。结果表明，β1-AAs 的持续作用显著降低了心肌组织和 H9c2 心肌细胞的自噬，并且 ERS 及其相关的凋亡途径明显被激活。此外，使用 mRFP-GFP-LC3 双标记腺病毒来检测心肌细胞自噬流，以确认β1-AAs 导致 H9c2 心肌细胞自噬流明显减少。ERS 抑制剂 4-苯丁酸（4-PBA）部分减轻了β1-AA 诱导的心肌细胞自噬减少，与雷帕霉素（Rapa）哺乳动物雷帕霉素靶蛋白抑制剂的作用一致。与单独用 4-PBA 或 Rapa 预处理相比，用 4-PBA 和 Rapa 的联合预处理对减轻β1-AA 诱导的自噬减少和β1-AA 诱导的心肌细胞凋亡有更大的作用。这项研究为β1-AAs 在心力衰竭患者的心肌细胞自噬和 ERS 稳态维持中的作用提供了实验依据。
