MDMA induces cardiac contractile dysfunction through autophagy upregulation and lysosome destabilization in rats
MDMA induces cardiac contractile dysfunction through autophagy upregulation and lysosome destabilization in rats
复制标题
MDMA 通过自噬上调和溶酶体不稳定诱导大鼠心脏收缩功能障碍
DOI：
10.1016/j.bbadis.2014.01.013
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Yoshida K
中科院分区：
文献类型：
--
作者：
Shintani-Ishida K;Saka K;Yamaguchi K;Hayashida M;Nagai H;Takemura G;Yoshida K
3，4-亚甲二氧基甲基苯丙胺（MDMA，“摇头丸”）滥用造成心脏毒性的潜在机制尚不清楚。自噬在各种病理环境中对心脏功能产生适应性或适应不良效应，但自噬在MDMA心脏毒性中的作用尚不清楚。在这里，我们研究了自噬可能参与MDMA诱导的心脏收缩功能障碍的机制。给大鼠腹腔注射MDMA（20 mg/kg）或生理盐水。左心室（LV）超声心动图和LV压力测量表明，MDMA给药后24小时LV收缩收缩力降低。蛋白质印迹分析显示MDMA给药后微管相关蛋白轻链3-II（LC 3-II）和组织蛋白酶D水平呈时间依赖性增加。电镜下可见心肌细胞内自噬空泡。MDMA上调了一磷酸腺苷活化蛋白激酶（AMPK）在Thr 172的磷酸化，上调了雷帕霉素哺乳动物靶蛋白（mTOR）在Thr 2446的磷酸化，上调了Raptor在Ser 792的磷酸化，上调了Unc 51样激酶（ULK 1）在Ser 555的磷酸化，表明自噬通过AMPK-mTOR途径激活。自噬抑制剂3-甲基腺嘌呤（3-MA）和氯喹（CQ）对LC 3-II水平的影响表明，MDMA增强自噬体形成，但减弱自噬体清除。MDMA还诱导释放组织蛋白酶到胞质溶胶中，免疫印迹法和电子显微镜分别显示心肌肌钙蛋白I（cTnI）降解和肌原纤维损伤。3-MA、CQ和一种溶酶体抑制剂E64 c可抑制cTnI蛋白水解，改善MDMA给药后的收缩功能障碍。总之，MDMA导致溶酶体不稳定的自噬-溶酶体途径激活后，通过释放的溶酶体蛋白酶损伤肌原纤维，并诱导左心室收缩功能障碍在大鼠心脏。
The underlying mechanisms of cardiotoxicity of 3,4-methylenedioxymethylamphetamine (MDMA, “ecstasy”) abuse are unclear. Autophagy exerts either adaptive or maladaptive effects on cardiac function in various pathological settings, but nothing is known on the role of autophagy in the MDMA cardiotoxicity. Here, we investigated the mechanism through which autophagy may be involved in MDMA-induced cardiac contractile dysfunction. Rats were injected intraperitoneally with MDMA (20 mg/kg) or saline. Left ventricular (LV) echocardiography and LV pressure measurement demonstrated reduction of LV systolic contractility 24 h after MDMA administration. Western blot analysis showed a time-dependent increase in the levels of microtubule-associated protein light chain 3-II (LC3-II) and cathepsin-D after MDMA administration. Electron microscopy showed the presence of autophagic vacuoles in cardiomyocytes. MDMA upregulated phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) at Thr172, mammalian target of rapamycin (mTOR) at Thr2446, Raptor at Ser792, and Unc51-like kinase (ULK1) at Ser555, suggesting activation of autophagy through the AMPK-mTOR pathway. The effects of autophagic inhibitors 3-methyladenine (3-MA) and chloroquine (CQ) on LC3-II levels indicated that MDMA enhanced autophagosome formation, but attenuated autophagosome clearance. MDMA also induced release of cathepsins into cytosol, and western blotting and electron microscopy showed cardiac troponin I (cTnI) degradation and myofibril damage, respectively. 3-MA, CQ, and a lysosomal inhibitor, E64c, inhibited cTnI proteolysis and improved contractile dysfunction after MDMA administration. In conclusion, MDMA causes lysosome destabilization following activation of the autophagy-lysosomal pathway, through which released lysosomal proteases damage myofibrils and induce LV systolic dysfunction in rat heart.