Small interfering RNA targeting heme oxygenase-1 (HO-1) reinforces liver apoptosis induced by ischemia-reperfusion injury in mice: HO-1 is necessary for cytoprotection.
We have shown that overexpression of heme oxygenase-1 (HO-1) prevents the liver inflammation response leading to ischemia and reperfusion injury (IRI). This study was designed to explore the precise function and mechanism of HO-1 cytoprotection in liver IRI by employing a small interfering RNA (siRNA) that effectively suppresses HO-1 expression both in vitro and in vivo. Using a partial lobar liver warm ischemia model, mice were injected with HO-1 siRNA/nonspecific control siRNA or Ad-HO-1/Ad-beta-gal. Those treated with HO-1 siRNA showed increased serum glutamic-oxaloacetic transaminase levels, significant liver edema, sinusoidal congestion/cytoplasmic vacuolization, and severe hepatocellular necrosis. In contrast, Ad-HO-1-pretreated animals revealed only minimal sinusoidal congestion without edema/vacuolization or necrosis. Administration of HO-1 siRNA significantly increased local neutrophil accumulation and the frequency of apoptotic cells. Mice treated with HO-1 siRNA were characterized by increased caspase-3 activity and reduced HO-1 expression, whereas those given Ad-HO-1 showed decreased caspase-3 activity and increased HO-1/Bcl-2/Bcl-x(L), data confirmed by use of an in vitro cell culture system. Thus, by using an siRNA approach this study confirms that HO-1 provides potent cytoprotection against hepatic IRI and regulates liver apoptosis. Indeed, siRNA provides a powerful tool with which to study gene function in a wide range of liver diseases.
Ke
Bibo
B
Dumont-UCLA Transplant Center, Department of Surgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA.
Shen
Xiu-Da
XD
Gao
Feng
F
Qiao
Bo
B
Ji
Haofeng
H
Busuttil
Ronald W
RW
Volk
Hans-Dieter
HD
Kupiec-Weglinski
Jerzy W
JW
D000818:Animals; D017209:Apoptosis; D001219:Aspartate Aminotransferases / Q000378:metabolism; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D019610:Cytoprotection; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism*; D020287:In Situ Nick-End Labeling; D008099:Liver / Q000201:enzymology* / Q000473:pathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism*; D015427:Reperfusion Injury / Q000201:enzymology / Q000473:pathology*; D052096:Warm Ischemia; D051020:bcl-X Protein / Q000378:metabolism
D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051020:bcl-X Protein; D051547:Heme Oxygenase-1; D001219:Aspartate Aminotransferases; D053148:Caspase 3