Caspase activity, in apoptosis

Wolf C. M. and Eastman A. (1999). The temporal relationship between protein phosphatase, mitochondrial cytochrome c release, and caspase activation in apoptosis. Exp. Cell Res. 247 505-513. 

Yang QH, Church-Hajduk R, Ren J, Newton ML, Du C (2003) Omi/HtrA2 cataljrtic cleavage of inhibitor of apoptosis (lAP) irreversibly inactivates lAPs and facilitates caspase activity in apoptosis. Genes Dev 17 1487-1496... 

Kumar, S., Colussi, P.A., 1999. Prodomains-adaptors-oligomerization the pursuit of caspase activation in apoptosis. Trend Biochem. Sci. 24, 1-4. 

Classic antioxidants, vitamin E, vitamin C, and others can suppress the activation of apoptosis. For example, ascorbic acid prevented cytochrome c release and caspase activation in human leukemia cells exposed to hydrogen peroxide [128], Pretreatment with A -acctylcystcinc, ascorbate, and vitamin E decreased homocysteine thiolactone-induced apoptosis in human promyelocytic leukemia HL-60 cells [129]. Resveratrol protected rat brain mitochondria from anoxia-reoxygenation damage by the inhibition of cytochrome c release and the reduction of superoxide production [130]. However, it should be mentioned that the proapoptotic effect of ascorbate, gallic acid, or epigallocatechin gallate has been shown in the same human promyelocytic leukemia cells [131]. 

The toxic effect of 7-oxysterols, 25- and 27-hydroxycholesterols and their involvement in LDL cytotoxicity have been extensively studied on the different vascular cell types (Lizard et al, 1999 Aupeix et al, 1995 Clare et al, 1995 Ramasamy et al, 1992). 7a and 7p-hydroxycholesterols, 7-ketocholesterol, 25 and 27-hydroxycholesterol induce apoptosis (Brown and Jessup, 1999 Lizard et al, 1999, 1998 Zhang et al, 1997 Hughes et al, 1994). 7p-hydroperoxycholesterol is one of the most toxic Oxysterols present in oxidized LDL (Brown and Jessup, 1999 Colles et al, 1996). 25-hydroxycholesterol, though less active (Aupeix et al 1995), is able to trigger a cytochrome c release and subsequent caspase activation in CHO cells, but also calcium inaease in relation with apoptosis (Rusinol et al, 2000). 

EdsaU, L.C., CuvUlier, O., Twitty, S., Spiegel, S. and MUstien, S., 2001, Sphingosine kinase expression regulates apoptosis and caspase activation in PCI 2 ceUs, J. Neurochem. 76 1573-1584. 

ELISA has been used for measuring caspase activity. For the ELISA of intracellular caspase activity at the very early stages of apoptosis, apoptotic cells are first lysed to isolate their intracellular contents. Different caspase activities in the cell lysate can then be determined by the addition of a caspase-specific tetrapeptide substrate that is conjugated to the color reporter molecule p-nitroanilide (pNA) (e.g., DEVD-pNA for caspase-3 and lETD-pNA for caspase-8). The cleavage of the substrate peptide by the caspase releases the chromophore pNA, which can be... 

Both techniques can be applied to most experimental models of apoptosis, including cells in culture and biopsies. In addition, techniques based on the cleavage of synthetic caspase substrates can be applied to caspases, activated in vitro and in vivo [82, 83], Whereas Western blotting is time consuming and mainly a qualitative assay, the detection of caspase activity by cleavage of synthetic substrates is a quantitative, relatively fast and sensitive method [82]. However, both techniques do not provide information about the type and distribution of the cells with activated caspases in the tissue examined. 

Kuida K, Haydar TF, Kuan CY, Gu Y, Taya C, Karasuyama H, et al. Reduced apoptosis and cytochrome c-mediated caspase activation in mice lacking caspase-9. Cell 1998 94 325-337. 

Gorman AM, Hirt UA, Zhivotovsky B, Orrenius S, Ceccatelli S. Application of a fluoro-metric assay to detect caspase activity in thymus tissue undergoing apoptosis in vivo. J Immunol Methods 1999 226 43-48. 

Ghosh S, May MJ, Kopp EB (1998) NF-kappa B and Rel proteins evolutionarily conserved mediators of immune responses. Annu Rev Immunol 16 225-260 GiU JS, Windebank AJ (2000) Ceramide initiates NFkappaB-mediated caspase activation in neuronal apoptosis. Neurobiol Dis 7 448-461... 

Another way to regulate caspases is by interaction with inhibitors. For example, fibroblasts that overexpress the growth-promoting transcription factor c-Myc die, because the caspase inhibitors (lAPs), inhibitors of apoptosis, are inactivated by phosphorylation. In Fig. 13.6 is shown how phosphorylation of a caspase inhibitor controls caspase activity and apoptosis. When cells are driven to proliferate by an overactive transcriptional activator, such as c-Myc, an unregulated active caspase, no longer restrained by the inhibitor, can overcome the effect of Bcl-2 and the cell will eventually die. Only when Bcl-2 is over-et ressed simultaneously with c-Myc, can cell death be prevented. Thus, Bcl-2 keeps the c-Myc signals in check.22,23... 

Caspase and calpain function in cell death bridging the gap between apoptosis and necrosis, Ann. Clin. Biochem. 42, 415 31, 2005 Ho, P.K. and Hawkins, C J., Mammalian initiator apoptotic caspases, FEES J. 272, 5436-5453,2005 Fardeel, B. and Orrenius, S., Apoptosis a basic biological phenomenon with wide-ranging implications in human disease, J. Intern. Med. 258, 479-517, 2005 Cathelin, S R6be, C Haddaoui, L. et al Identification of proteins cleaved downstream of caspase activation in monocytes undergoing macrophage differentiation, J. Biol. Chem. 281, 17779-17788, 2006. 

Caspase recruitment domain, mediates the formation of larger protein complexes via direct interactions between individual cards, involved in the regulation of caspase activation and apoptosis... 

Heyneanol A (684) was demonstrated to possess anti-tumor activity, which may be mediated by apoptosis caused by cytochrome c release and caspase activation in human leukemic U937 cells [476]. 

In addition to cytochrome c, a second mitochondria-derived activator of caspases (SMAC) is also released from the mitochondrial intermembrane space. SMAC binds to an inhibitor of apoptosis protein (IAP) to prevent spontaneous caspase activation in a healthy cell. The IAP that binds to caspase-9 is called X-LAP. When SMAC binds to X-IAP, X-IAP is released from caspase-9. Autocleavage of the caspase-9 prodomain then exposes the catalytic site. Caspase-9 then activates caspase-3 which immediately cuts out the X-IAP binding domain from procaspase-9, preventing X-IAP inhibition and accelerating activation of both caspase-3 and caspase-9 (Fig. 13.11a), which digest all of the cell s proteins. The apoptotic cells also possess a caspase-activated DNase (CAD) that fragments chromosomal DNA. Other proteins from the mitochondrial intermembrane space can activate caspases by related mechanisms. The combination of mechanisms, or the overwhelming activation of any one of them, irreversibly propels a cell into apoptosis. 

Hirashima, Y., Kurimoto, M., Nogami, K., Endo, S., Saitoh M., Ohtani, O., Nagata, T., Mura-guchi. A., and Takaku, A., 1999. Correlation of glutamate-induced apoptosis with caspase activities in cultured rat cerebral cortical neurons. Brain Res., 849, pp. 109-118. 

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