Cellular and molecular studies on cisplatin-induced apoptotic cell death in rat kidney

Abstract

Using morphological and molecular approaches, we characterized cisplatin-induced cell necrosis and apoptosis in rat kidney. Male Sprague-Dawley rats ( n=5 per group) received a single intraperitoneal injection of either cisplatin (5 mg/kg) or saline, and were killed on day 5. Functionally, cisplatin-treated rats developed polyuric acute renal failure. Morphologically, kidneys of cisplatin-treated rats showed overt tubular necrosis associated with apoptosis in the corticomedullary junction. Cell necrosis was segment-specific and was distributed in radial fashion at the corticomedullary junction. The apoptosis was limited to discrete cells in apparently intact tubules in the vicinity of the necrosed tubules. The apoptotic changes were confirmed by TUNEL (TdT-mediated deoxyuridine triphosphate nick-end labeling) and staining for cleaved caspase-3. Analysis of outer medullary tissue for apoptosis-related molecules by RNase protection assay revealed a significant increase in the expression of pro-apoptotic mRNAs (caspases 1, 2, and 8, and Bax) in cisplatin-treated rats. On the other hand, the expression of mRNA for the anti-apoptotic Bcl-2 did not change, resulting in a decrease in relative ratio of Bcl-2/Bax, and thus favoring apoptosis. The above changes were paralleled by a marked increase in caspase-3 precursor, the executioner protease. Furthermore, these pro-apoptotic molecular changes were associated with a 3-fold increase in the activity of JNK1 in the outer medulla, but not in the cortex, of cisplatin-treated rat kidneys, localizing to the site of maximal apoptosis. Upregulation of JNK1 activity in the outer medulla was not accompanied by changes in the activities of ERK or p38 kinase. In conclusion, these data suggest that cisplatin-induced apoptotic cell death in native kidney may be mediated by cooperative activation of the JNK1 pathway and Bax in the outer medulla.

Transcriptional activation of caspase-6 and -7 genes by cisplatin-induced p53 and its functional significance in cisplatin nephrotoxicity

“…Thus regulation of the expression of executioner caspases is crucial prior to the execution of cell death. Several studies including ours have previously demonstrated activation of executioner caspases (caspase-3/7 and -6) in both in vitro 12,13 and in vivo 14,15 models of cisplatin-induced AKI. Similarly, induction of p53 transcription factor was demonstrated in RTECs in both in vitro [16][17][18] and in vivo 19 studies of cisplatin AKI.…”

Regulation of PUMA-α by p53 in cisplatin-induced renal cell apoptosis

“…Depending on its concentration, cisplatin induces necrosis as well as apoptosis in these cells, leading to acute renal failure. Multiple signaling pathways are activated by cisplatin in renal tubular cells (Baliga et al, 1998;Megyesi et al, 1998;Shiraishi et al, 2000;Kaushal et al, 2001;Nowak, 2002;Park et al, 2002;Ramesh and Reeves, 2002;Liu and Baliga, 2003;Tsuruya et al, 2003;Arany et al, 2004;Li et al, 2004;Sheikh-Hamad et al, 2004;Yu et al, 2005); however, it is unclear how these signals are integrated to determine cell injury and death (Arany and Safirstein, 2003).…”

Untitled

“…In kidneys, cisplatin accumulates in renal tubular cells, resulting in cell injury and death, contributing to the development of AKI (see [1,2] for reviews). Research during the last few years has identified several important signaling pathways that lead to tubular-cell apoptosis during cisplatin nephrotoxicity, including mitogen-activated protein kinase, p53 and others (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14).…”