The Second School of Clinical Medicine, Southern Medical University, Guangzhou, 510515, China.
The Sixth Affiliated Hospital, School of Medicine, South China University of Technology, Foshan, 528200, China.
In Vitro Cell Dev Biol Anim. 2023 Apr;59(4):277-288. doi: 10.1007/s11626-023-00768-0. Epub 2023 May 8.
Morroniside can prevent myocardial injury caused by ischemia and hypoxia, which can be used to treat acute myocardial infarction (AMI). Hypoxia can cause apoptosis and autophagic death of cardiomyocytes. Morroniside has the ability to inhibit apoptosis and autophagy. However, the relationship between Morroniside-protected cardiomyocytes and two forms of death is unclear. The effects of Morroniside on the proliferation, apoptosis level, and autophagic activity of rat cardiomyocyte line H9c2 under hypoxia were first observed. Next, the roles of Morroniside in the phosphorylation of JNK and BCL2, BCL2-Beclin1, and BCL2-Bax complexes as well as mitochondrial membrane potential in H9c2 cells were evaluated upon hypoxia. Finally, the significance of BCL2 or JNK in Morroniside-regulated autophagy, apoptosis, and proliferation in H9c2 cells was assessed by combining Morroniside and BCL2 competitive inhibitor (ABT-737) or JNK activator (Anisomycin). Our results showed that hypoxia promoted autophagy and apoptosis of H9c2 cells, and inhibited their proliferation. However, Morroniside could block the effect of hypoxia on H9c2 cells. In addition, Morroniside could inhibit JNK phosphorylation, BCL2 phosphorylation at the Ser70 and Ser87 sites, and the dissociation of BCL2-Beclin1 and BCL2-Bax complexes in H9c2 cells upon hypoxia. Moreover, the reduction of mitochondrial membrane potential in H9c2 cells caused by hypoxia was improved by Morroniside administration. Importantly, the inhibited autophagy, apoptosis, and promoted proliferation in H9c2 cells by Morroniside were reversed by the application of ABT-737 or Anisomycin. Overall, Morroniside inhibits Beclin1-dependent autophagic death and Bax-dependent apoptosis via JNK-mediated BCL2 phosphorylation, thereby improving the survival of cardiomyocytes under hypoxia.
莫诺苷可预防缺血缺氧引起的心肌损伤，可用于治疗急性心肌梗死（AMI）。缺氧可导致心肌细胞凋亡和自噬性死亡。莫诺苷具有抑制凋亡和自噬的能力。然而，莫诺苷保护的心肌细胞与两种形式的死亡之间的关系尚不清楚。本研究首先观察了莫诺苷对缺氧条件下大鼠心肌细胞系 H9c2 增殖、凋亡水平和自噬活性的影响。接下来，评价了莫诺苷对 H9c2 细胞 JNK 和 BCL2、BCL2-Beclin1 和 BCL2-Bax 复合物磷酸化以及线粒体膜电位的作用。最后，通过莫诺苷与 BCL2 竞争抑制剂（ABT-737）或 JNK 激活剂（Anisomycin）联合应用，评估 BCL2 或 JNK 在莫诺苷调节 H9c2 细胞自噬、凋亡和增殖中的意义。结果表明，缺氧促进 H9c2 细胞自噬和凋亡，抑制其增殖。然而，莫诺苷可以阻断缺氧对 H9c2 细胞的影响。此外，莫诺苷可以抑制 H9c2 细胞缺氧时 JNK 磷酸化、BCL2 丝氨酸 70 和丝氨酸 87 位点磷酸化以及 BCL2-Beclin1 和 BCL2-Bax 复合物解离。而且，莫诺苷可改善缺氧引起的 H9c2 细胞线粒体膜电位降低。重要的是，ABT-737 或 Anisomycin 的应用逆转了莫诺苷对 H9c2 细胞自噬、凋亡的抑制和增殖的促进作用。总之，莫诺苷通过 JNK 介导的 BCL2 磷酸化抑制 Beclin1 依赖性自噬性死亡和 Bax 依赖性凋亡，从而改善缺氧条件下心肌细胞的存活。
