Essential contribution of caspase 3/CPP32 to apoptosis and its associated nuclear changes

Abstract

Caspases are fundamental components of the mammalian apoptotic machinery, but the precise contribution of individual caspases is controversial. CPP32 (caspase 3) is a prototypical caspase that becomes activated during apoptosis. In this study, we took a comprehensive approach to examining the role of CPP32 in apoptosis using mice, embryonic stem (ES) cells, and mouse embryonic fibroblasts (MEFs) deficient for CPP32. CPP32 ex3−/− mice have reduced viability and, consistent with an earlier report, display defective neuronal apoptosis and neurological defects. Inactivation of CPP32 dramatically reduces apoptosis in diverse settings, including activation-induced cell death (AICD) of peripheral T cells, as well as chemotherapy-induced apoptosis of oncogenically transformed CPP32 −/− MEFs. As well, the requirement for CPP32 can be remarkably stimulus-dependent: In ES cells, CPP32 is necessary for efficient apoptosis following UV-but not ␥-irradiation. Conversely, the same stimulus can show a tissue-specific dependence on CPP32: Hence, TNF␣ treatment induces normal levels of apoptosis in CPP32 deficient thymocytes, but defective apoptosis in oncogenically transformed MEFs. Finally, in some settings, CPP32 is required for certain apoptotic events but not others: Select CPP32 ex3−/− cell types undergoing cell death are incapable of chromatin condensation and DNA degradation, but display other hallmarks of apoptosis. Together, these results indicate that CPP32 is an essential component in apoptotic events that is remarkably system-and stimulus-dependent. Consequently, drugs that inhibit CPP32 may preferentially disrupt specific forms of cell death.

Role of caspases and possible involvement of retinoblastoma protein during TGFβ-mediated apoptosis of human B lymphocytes

“…In contrast, TGFb-mediated-nuclear fragmentation was reproducibly inhibited to approximately the same extent by ZVAD-fmk and DEVD-fmk. This strongly suggests that the nuclear fragmentation observed during TGFbmediated apoptosis is more directly under the control of caspase-3 as it has been reported in other experimental systems (Janicke et al, 1998;Shiokawa et al, 1997;Toyoshima et al, 1997;Woo et al, 1998).…”

“…The remaining cleavage of PARP in DEVD pre-treated cells was probably due to caspases other than caspase-3 also being able to BL41 cells (0.5 10 6 /ml) were cultured for 72 h without (control) or in the presence of TGFb (1 ng/ml) alone or with ZVAD-fmk (100 mM) or the combination of TGFb and ZVAD-fmk. Total number and per cent of viable cells were quanti®ed by counting of trypan blue excluding cells cleave PARP in vivo albeit with a lower e ciency (Patel et al, 1996;Woo et al, 1998). We therefore used this concentration to study the involvement of caspase-3 during TGFb-mediated apoptosis.…”

MAPK signaling in neurodegeneration: influences of flavonoids and of nitric oxide

“…The defect in the execution of apoptotic cell death was caused by the failure to initiate JNK-induced cytochrome c release from the mitochondria [204]. This malfunction is significant since it is critical for the subsequent sequential activation of Apaf-1 [120], the initiator-caspase caspase-9 [76] and finally the effector-caspase caspase-3 [217] all of which are essential in the execution of apoptosis. Tournier et al [204] suggested that the apoptotic response is suppressed in JNK null MEF due to the absence of JNK, which is needed to initiate the apoptotic cascade (Fig.…”

Perforin‐dependent activation‐induced cell death acts through caspase 3 but not through caspases 8 or 9

“…B6 mice were ordered from Jackson Laboratories (Bar Harbor, ME) whereas pko mice on the B6 background were bred in the animal colony from stock provided by Dr. H. Hentgartner [42]. Caspase 3 -/-mice and heterozygous littermates [24] and caspase 9 -/-/RAG2 -/-and wild-type/RAG2 -/-chimeras [29] were generated as described.…”

“…Other apoptotic events act through compromise of mitochondrial activity and lead to activation of caspase 9 (reviewed in [21,22]). Both receptor-mediated and mitochondrial pathways converge upon caspase 3 [23,24], which causes DNA fragmentation through degradation of a DNase inhibitor (ICAD) and release of a caspase-activated DNase [25][26][27].…”