Maduramicin induces cardiotoxicity via Rac1 signaling-independent methuosis in H9c2 cells
Maduramicin induces cardiotoxicity via Rac1 signaling-independent methuosis in H9c2 cells
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Maduramicin 通过 Rac1 信号独立的方法在 H9c2 细胞中诱导心脏毒性
DOI：
10.1002/jat.4175
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发表时间：
2021-04-22
影响因子：
3.3
通讯作者：
Jiang, Shanxiang
中科院分区：
文献类型：
--
作者：
Gao, Xiuge;Ji, Chunlei;Jiang, Shanxiang
临床上，马杜拉米星在靶动物和非靶动物中经常引起严重的心脏毒性。凋亡性和非凋亡性细胞死亡介导了其心脏毒性；然而，马杜拉米星诱导的潜在非凋亡性细胞死亡仍不清楚。在目前的研究中，最近在哺乳动物细胞中定义了一种由马杜拉米星引起的非凋亡性细胞死亡。以体外培养的大鼠心肌细胞H9c2为模型，马杜霉素(0.0625~5mUg/mL)作用24 h后，H9c2细胞呈现过度的胞浆空泡化，且呈时间和浓度依赖性。马杜霉素诱导的空泡为单膜透亮，不是线粒体、内质网、溶酶体和高尔基体等细胞器肿胀所致。此外，细胞外液相标志物葡聚糖-Alexa荧光素488内化到H9c2细胞中，证明了马杜霉素诱导的细胞质空泡是由微胞吞作用产生的。耐人寻味的是，这些细胞质液泡获得了晚期内体和溶酶体的一些特征，而不是早期内体和自噬体内的一些特征。空泡H+-ATPase抑制剂巴非霉素A1能有效地阻止细胞质空泡的产生，并降低马杜霉素对H9c2细胞的细胞毒作用。机制研究表明，Maduramicin在mRNA和蛋白水平上激活了H-Ras-rac1信号通路。然而，药物抑制和siRNA敲除可挽救马杜霉素诱导的H9c2细胞毒性，但不能减轻细胞质空泡化。基于这些发现，马杜拉米星通过Rac-1信号非依赖性的严重胞浆空泡化诱导H9c2细胞的甲硫化。
Maduramicin frequently induces severe cardiotoxicity in target and nontarget animals in clinic. Apoptotic and non-apoptotic cell death mediate its cardiotoxicity; however, the underlying non-apoptotic cell death induced by maduramicin remains unclear. In current study, a recently described non-apoptotic cell death "methuosis" caused by maduramicin was defined in mammalian cells. Rat myocardial cell H9c2 was used as an in vitro model, showing excessively cytoplasmic vacuolization upon maduramicin (0.0625-5 mu g/mL) exposure for 24 h. Maduramicin-induced reversible cytoplasmic vacuolization of H9c2 cells in a time- and concentration-dependent manner. The vacuoles induced by maduramicin were phase lucent with single membrane and were not derived from the swelling of organelles such as mitochondria, endoplasmic reticulum, lysosome, and Golgi apparatus. Furthermore, maduramicin-induced cytoplasmic vacuoles are generated from micropinocytosis, which was demonstrated by internalization of extracellular fluid-phase marker Dextran-Alexa Fluor 488 into H9c2 cells. Intriguingly, these cytoplasmic vacuoles acquired some characteristics of late endosomes and lysosomes rather than early endosomes and autophagosomes. Vacuolar H+-ATPase inhibitor bafilomycin A1 efficiently prevented the generation of cytoplasmic vacuoles and decreased the cytotoxicity of H9c2 cells triggered by maduramicin. Mechanism studying indicated that maduramicin activated H-Ras-Rac1 signaling pathway at both mRNA and protein levels. However, the pharmacological inhibition and siRNA knockdown of Rac1 rescued maduramicin-induced cytotoxicity of H9c2 cells but did not alleviate cytoplasmic vacuolization. Based on these findings, maduramicin induces methuosis in H9c2 cells via Rac-1 signaling-independent seriously cytoplasmic vacuolization.