p53-dependent caspase-2 activation in mitochondrial release of apoptosis-inducing factor and its role in renal tubular epithelial cell injury.
We demonstrate the role of p53-mediated caspase-2 activation in the mitochondrial release of apoptosis-inducing factor (AIF) in cisplatin-treated renal tubular epithelial cells. Gene silencing of AIF with its small interfering RNA (siRNA) suppressed cisplatin-induced AIF expression and provided a marked protection against cell death. Subcellular fractionation and immunofluorescence studies revealed cisplatin-induced translocation of AIF from the mitochondria to the nuclei. Pancaspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone or p53 inhibitor pifithrin-alpha markedly prevented mitochondrial release of AIF, suggesting that caspases and p53 are involved in this release. Caspase-2 and -3 that were predominantly activated in response to cisplatin provided a unique model to study the role of these caspases in AIF release. Cisplatin-treated caspase-3 (+/+) and caspase-3 (-/-) cells exhibited similar AIF translocation to the nuclei, suggesting that caspase-3 does not affect AIF translocation, and thus, caspase-2 may be involved in the translocation. Caspase-2 inhibitor benzyloxycarbonyl-Val-Asp-Val-Ala-Asp-fluoromethylketone or down-regulation of caspase-2 by its siRNA significantly prevented translocation of AIF. Caspase-2 activation was a critical response from p53, which was markedly induced and phosphorylated in cisplatin-treated cells. Overexpression of p53 not only resulted in caspase-2 activation but also mitochondrial release of AIF. The p53 inhibitor pifithrin-alpha or p53 siRNA prevented both cisplatin-induced caspase-2 activation and mitochondrial release of AIF. Caspase-2 activation was dependent on the p53-responsive gene, PIDD, a death domain-containing protein that was induced by cisplatin in a p53-dependent manner. These results suggest that caspase-2 activation mediated by p53 is an important pathway involved in the mitochondrial release of AIF in response to cisplatin injury.
Seth
Rohit
R
Department of Medicine, University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare System, Little Rock, Arkansas 72205, USA.
Yang
Cheng
C
Kaushal
Varsha
V
Shah
Sudhir V
SV
Kaushal
Gur P
GP
D000590:Amino Acid Chloromethyl Ketones / Q000378:metabolism; D000818:Animals; D000970:Antineoplastic Agents / Q000633:toxicity; D051033:Apoptosis Inducing Factor; D052160:Benzothiazoles; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D053143:Caspase 2; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002945:Cisplatin / Q000633:toxicity; D015853:Cysteine Proteinase Inhibitors / Q000378:metabolism; D053418:Death Domain Receptor Signaling Adaptor Proteins; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D005420:Flavoproteins / Q000235:genetics / Q000378:metabolism*; D007684:Kidney Tubules / Q000166:cytology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism; D014050:Toluene / Q000031:analogs & derivatives / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
D000590:Amino Acid Chloromethyl Ketones; D000970:Antineoplastic Agents; D051033:Apoptosis Inducing Factor; D052160:Benzothiazoles; D002352:Carrier Proteins; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D053418:Death Domain Receptor Signaling Adaptor Proteins; D005420:Flavoproteins; D008565:Membrane Proteins; C494830:AIFM1 protein, mouse; C414729:Pidd1 protein, mouse; D034741:RNA, Small Interfering; D013844:Thiazoles; D016159:Tumor Suppressor Protein p53; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D014050:Toluene; C121565:pifithrin; C505409:Casp3 protein, mouse; D053143:Caspase 2; D053148:Caspase 3; D020169:Caspases; D002945:Cisplatin