Caspase activation and neuroprotection in caspase-3- deficient mice after in vivo cerebral ischemia and in vitro oxygen glucose deprivation

Abstract

Caspase-3 is a major cell death effector protease in the adult and neonatal nervous system. We found a greater number and higher density of cells in the cortex of caspase-3 ؊/؊ adult mice, consistent with a defect in developmental cell death. Caspase-3 ؊/؊ mice were also more resistant to ischemic stress both in vivo and in vitro. After 2 h of ischemia and 48 h of reperfusion, cortical infarct volume was reduced by 55%, and the density of terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling-positive cells was decreased by 36% compared with wild type. When subjected to oxygen-glucose deprivation (2 h), cortical neurons cultured from mice deficient in caspase-3 expression were also more resistant to cell death by 59%. Mutant brains showed caspase-specific poly-(ADP-ribose) polymerase cleavage product (85-kDa fragment) in vivo and in vitro, suggesting redundant mechanisms and persistence of caspase-mediated cell death. In the present study, we found that caspase-8 mediated poly(ADP-ribose) polymerase cleavage in caspase-3 ؊/؊ neurons in vivo and in vitro. In addition, mutant neurons showed no evidence of compensatory activation by caspase-6 or caspase-7 after ischemia. Taken together, these data extend the pharmacological evidence supporting an important role for caspase-3 and caspase-8 as cell death mediators in mammalian cortex and indicate the potential advantages of targeting more than a single caspase family member to treat ischemic cell injury.

Mice overexpressing human caspase 3 appear phenotypically normal but exhibit increased apoptosis and larger lesion volumes in response to transient focal cerebral ischaemia

“…14,[56][57][58] Moreover, studies in caspase 3-deficient mice indicate that these animals are relatively resistant to ischaemic insults with smaller lesions than their WT littermates. 59 In keeping with these literature reports, the studies presented here demonstrate that mice overexpressing human caspase 3 exhibit more apoptotic cell death and larger cerebral lesions than their WT littermates. Similarly, heart-targeted overexpression of caspase 3 resulted in increased lesion size following myocardial ischaemia-reperfusion.…”

Tissue inhibitor of metalloproteinases-3 facilitates Fas-mediated neuronal cell death following mild ischemia

“…To investigate the convergent roles of TIMP-3 and death receptor signaling in neuronal injury following ischemia, we utilized a common in vitro model of OGD. Previous work has demonstrated that 2 h of OGD leads to delayed apoptotic neuronal death in murine cortical cultures, associated with activation of both caspases 8 and 3, 28 and that neuronal apoptosis in response to OGD is dependent on death receptor activation. 5 To characterize the time course of the OGD response, we exposed wild-type cortical cultures to 2 h of OGD or control conditions and assessed neuronal survival at 12, 24 or 48 h following return to normoxic conditions.…”

Tanshinone IIA attenuates the cerebral ischemic injury-induced increase in levels of GFAP and of caspases-3 and -8

“…Caspase-3 can be activated by upstream initiator caspases such as caspase-8 through two distinct pathways, i.e., the death receptor-mediated extrinsic caspase-8 pathway or the mitochondria dependent-cytochrome c/caspase-9 intrinsic pathway, respectively (Hu et al, 2003). Caspase-3 has been shown to be up-regulated and activated in ischemic brain tissue (Rami et al, 2003), and genetic deletion or pharmacologic inhibition of caspase-3 leads to reduced neuronal death in the ischemic brain (Le et al, 2002). The protective effect of neuronal deletion of caspase-8 has also been shown 14 following impact injury to the brain.…”