Amelioration of ischemic mitochondrial injury and Bax-dependent outer membrane permeabilization by Mdivi-1.
OBJECTIVE
Disturbance of the balance between mitochondrial fission and fusion has been implicated in cerebral ischemia and several neurodegenerative diseases, whereas the underlying mechanisms remain poorly understood. In the present study, we attempted to investigate the role of dynamin-related protein 1 (Drp1), a key mitochondrial fission protein, in the pathogenesis of cerebral ischemia.


METHODS
Using Drp1 siRNA or Mdivi-1, a small molecule inhibitor of Drp1, we examined the effect of Drp1 knockdown or inhibition on oxygen-glucose deprivation (OGD)-induced mitochondrial dysfunction and death of SH-SY-5Y cells. Cell death and viability were evaluated with LDH and MTT assays, respectively, and mitochondrial morphology, mitochondrial membrane potential (Δψm), and ATP production were assessed using epifluorescence microscopy, flow cytometry, and HPLC, respectively. Moreover, to examine the effect of Drp1 inhibition on ischemic brain injury, middle cerebral artery occlusion (MCAO) mice were injected (i.p.) with Mdivi1, and blood-brain barrier permeability, brain water content, and cell apoptosis were assessed.


RESULTS
Knockdown or inhibition of Drp1 by Mdivi-1 significantly attenuated OGD-induced cell death in SH-SY-5Y cells, associated with reduced morphological change of mitochondria and attenuated Bax insertion,oligomerization. Moreover, treatment of the MCAO mice with Mdivi-1 remarkably reduced the infarct volume and neurological deficits in a dose-dependent manner, associated with marked reduction of mitochondrial fragmentation and BAX expression.


CONCLUSIONS
Down-regulation or inhibition of Drp1 may reduce cerebral ischemic damage through maintaining normal mitochondrial morphology and function, and decreasing Bax insertion and oligomerization in mitochondria.
Department of Neurology, The 10th People's Hospital, Tongji University, Shanghai, China.
Yan-Xin
YX
Zhao
Mei
M
Cui
Shu-Fen
SF
Chen
Qiang
Q
Dong
Xue-Yuan
XY
Liu
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000503:physiopathology; D001929:Brain Edema / Q000188:drug therapy / Q000209:etiology; D002199:Capillary Permeability / Q000187:drug effects; D015687:Cell Hypoxia / Q000187:drug effects; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000187:drug effects*; D005947:Glucose / Q000172:deficiency; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D009447:Neuroblastoma / Q000473:pathology; D052999:Quinazolinones / Q000494:pharmacology / Q000627:therapeutic use*; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
C549041:3-(2,4-dichloro-5-methoxyphenyl)-2-sulfanyl-4(3H)-quinazolinone; C494827:Bax protein, mouse; D052999:Quinazolinones; D051028:bcl-2-Associated X Protein; D005947:Glucose
Bax oligomerization; Drp1; Mdivi-1; Mitochondrial dynamics; Neurons