Intracellular pH Regulates TRAIL-Induced Apoptosis and Necroptosis in Endothelial Cells.

Intracellular pH Regulates TRAIL-Induced Apoptosis and Necroptosis in Endothelial Cells. J Immunol Res. 2017;2017:1503960 Authors: Zhang ZX, Gan I, Pavlosky A, Huang X, Fuhrmann B, Jevnikar AM Abstract During ischemia or inflammation of organs, intracellular pH can decrease if acid production exceeds buffering capacity. Thus, the microenvironment can expose parenchymal cells to a reduced extracellular pH which can alter pH-dependent intracellular functions. We have previously shown that while silencing caspase-8 in an in vivo ischemia reperfusion injury (IRI) model results in improved organ function and survival, removal of caspase-8 function in a donor organ can paradoxically result in enhanced receptor-interacting protein kinase 1/3- (RIPK1/3-) regulated necroptosis and accelerated graft loss following transplantation. In our current study, TRAIL- (TNF-related apoptosis-inducing ligand-) induced cell death in vitro at neutral pH and caspase-8 inhibition-enhanced RIPK1-dependent necroptotic death were confirmed. In contrast, both caspase-8 inhibition and RIPK1 inhibition attenuated cell death at a cell pH of 6.7. Cell death was attenuated with mixed lineage kinase domain-like (MLKL) silencing, indicating that MLKL membrane rupture, a distinctive feature of necroptosis, occurs regardless of pH. In summary, there is a distinct regulatory control of apoptosis and necroptosis in endothelial cells at different intracellular pH. These res...
Source: Journal of Immunology Research - Category: Allergy & Immunology Tags: J Immunol Res Source Type: research