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.
Department of Medicine, University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare System, Little Rock, Arkansas 72205, USA.
Rohit
R
Seth
Cheng
C
Yang
Varsha
V
Kaushal
Sudhir V
SV
Shah
Gur P
GP
Kaushal
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