Targeting Dynamin 2 as a Novel Pathway to Inhibit Cardiomyocyte Apoptosis Following Oxidative Stress.
OBJECTIVE
Inhibition of Drp-1-mediated mitochondrial fission limits reactive oxygen species (ROS) production and apoptosis in cardiomyocytes subjected to ischemia/reperfusion injury. It remains unknown if Dynamin 2 inhibition results in similar protective effects. Here we studied the role of Dynamin 2 in cardiomyocyte oxidative stress-induced apoptosis and ROS production.


METHODS
The effect of lentiviral shRNA (lv5-shRNA) mediated Dynamin 2 knockdown on apopotosis, mitochondria, and ROS production were studied in neonatal mouse cardiomycytes, which were further treated with either selective Drp1 inhibitor mdivi-1 or the Dynamin 2/Drp1 inhibitor Dynasore. Apoptosis was evaluated by flow cytometry. Mitochondrial morphology and transmembrane potential (ΔΨm) were studied by confocal microscopy, and ROS production was detected by dichlorofluorescein diacetate.


RESULTS
Inhibition of Drp1 and Dynamin 2 protected against mitochondrial fragmentation, maintained ΔΨm, attenuated cellular ROS production and limited apoptosis. Moreover, Lv5-shRNA mediated knockdown of Dynamin 2 alleviated mitochondrial fragmentation, and reduced both ROS production and oxidative stress-induced apoptosis. The protective effects of Dynamin 2 knockdown were enhanced by Dynasore, indicating an added benefit.


CONCLUSIONS
Oxidative stress-induced apoptosis and ROS production are attenuated by not only Drp1 inhibition but also Dynamin 2 inhibition, implicating Dynamin 2 as a mediator of oxidative stress in cardiomyocytes.
Department of Cardiology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
Danchen
D
Gao
Jian
J
Yang
Yutao
Y
Wu
Qiwen
Q
Wang
Qiaoling
Q
Wang
En Yin
EY
Lai
Jianhua
J
Zhu
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D034285:Dynamin II / Q000378:metabolism*; D034281:Dynamins / Q000378:metabolism; D055785:Gene Knockdown Techniques; D020868:Gene Silencing / Q000187:drug effects; D006835:Hydrazones / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D016086:Lentivirus / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D014176:Protein Biosynthesis / Q000187:drug effects; D034741:RNA, Small Interfering / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013312:Stress, Physiological / Q000187:drug effects
D006835:Hydrazones; C511794:N'-(3,4-dihydroxybenzylidene)-3-hydroxy-2-naphthahydrazide; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; C486391:Dnm1l protein, mouse; D034285:Dynamin II; D034281:Dynamins