Induction of autophagy by Tongxinluo through the MEK/ERK pathway protects human cardiac microvascular endothelial cells from hypoxia/reoxygenation injury.
: In contrast to cardiomyocytes, autophagy in cardiac microvascular endothelial cells (CMECs) during ischemia/reperfusion (I/R) injury has not been fully investigated. Tongxinluo (TXL), a traditional Chinese medicine, was shown to be vascular protective. We aimed to elucidate the role of autophagy and its regulatory mechanisms by TXL in CMECs subjected to I/R injury. CMECs were exposed to different treatments for 30 minutes and subjected to hypoxia/reoxygenation each for 2 hours. The results indicated that hypoxia/reoxygenation significantly induced autophagy, as identified by an increased number of monodansylcadaverine-positive CMECs, increased autophagosome formation, and a higher type II/type I of light chain 3 ratio, but not Beclin-1 expression. Autophagy inhibition using 3-methyladenine was proapoptotic, but rapamycin-induced autophagy was antiapoptotic. TXL enhanced autophagy and decreased apoptosis in a dose-dependent manner, reaching its largest effect at 800 μg/mL. 3-methyladenine attenuated the TXL-promoted autophagy and antiapoptotic effects, whereas rapamycin had no additional effects compared with TXL alone. TXL upregulated mitogen-activated protein kinase and extracellular signal-regulated kinase (ERK) phosphorylation; however, PD98059 abrogated ERK phosphorylation and decreased autophagy and increased apoptosis compared with TXL alone. These results suggest that autophagy is a protective mechanism in CMECs subjected to I/R injury and that TXL can promote autophagy through activation of the mitogen-activated protein kinase/ERK pathway.
State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Hehe
H
Cui
Xiangdong
X
Li
Na
N
Li
Kang
K
Qi
Qing
Q
Li
Chen
C
Jin
Qian
Q
Zhang
Leipei
L
Jiang
Yuejin
Y
Yang
D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy / Q000187:drug effects*; D018929:Cell Culture Techniques; D015687:Cell Hypoxia / Q000187:drug effects; D002460:Cell Line; D003331:Coronary Vessels / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D042783:Endothelial Cells / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D046529:Microscopy, Electron, Transmission; D055806:Microvessels / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D010100:Oxygen / Q000378:metabolism*
D004365:Drugs, Chinese Herbal; C513941:tongxinluo; D010100:Oxygen