Inhibition by [corrected] ursolic acid of [corrected] calcium-induced mitochondrial permeability transition and release of two proapoptotic proteins.
The possible inhibition by [corrected] ursolic acid (UA) of [corrected] mitochondrial permeability transition (MPT) in mouse liver was investigated to identify the mechanisms underlying the hepatoprotective effect of UA. The effect of UA on liver MPT induced by Ca2+ was assessed by measuring changes in mitochondrial volume, mitochondrial membrane potential (MMP), release of matrix Ca2+, and transfer of cytochrome c (Cyt c) and apoptosis-inducing factor (AIF) from the intermembrane space to the cytoplasm. The results showed that obvious mitochondrial swelling, loss of MMP, and release of matrix Ca2+ occurred after the addition of 50 microM Ca2+. However, preincubation with 20, 50 or 100 microg ml(-1) UA significantly blocked the above changes. Addition of 100 microg ml(-1) UA inhibited on mitochondrial swelling by 73.2% after 5 min, while the MMP dissipating and Ca2+ releasing were, respectively, suppressed by 59.3% and 54.1% after 3 min. In addition, Western blot analysis showed Cyt c and AIF transferred from mitochondrial pellet to the supernatant after the addition of 50 microM Ca2+, but the process was significantly inhibited by various concentrations of UA. The results suggest that the mechanisms underlying the hepatoprotection of UA may be related to its direct inhibitory action on MPT.
Tang
Xinhui
X
School of Medicine, Nanjing University, 22 Hankou Road, Nanjing 210093, China.
Gao
Jing
J
Chen
Jin
J
Fang
Feng
F
Wang
Yanping
Y
Dou
Huan
H
Xu
Qiang
Q
Qian
Zhongming
Z
D000818:Animals; D017209:Apoptosis; D051033:Apoptosis Inducing Factor; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D045304:Cytochromes c / Q000378:metabolism; D005420:Flavoproteins / Q000378:metabolism; D007473:Ion Channels / Q000037:antagonists & inhibitors*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D014315:Triterpenes / Q000494:pharmacology*; D000097245:Ursolic Acid
D051033:Apoptosis Inducing Factor; D002118:Calcium; D045304:Cytochromes c; D005420:Flavoproteins; D007473:Ion Channels; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D014315:Triterpenes; D000097245:Ursolic Acid; C494830:AIFM1 protein, mouse