Skip Navigation

Publication Detail

Title: PARP-1 hyperactivation and reciprocal elevations in intracellular Ca2+ during ROS-induced nonapoptotic cell death.

Authors: Zhang, Fengjiao; Xie, Ruiye; Munoz, Frances M; Lau, Serrine S; Monks, Terrence J

Published In Toxicol Sci, (2014 Jul)

Abstract: The generation of reactive oxygen species (ROS) has been implicated in the pathogenesis of renal ischemia/reperfusion injury, and many other pathological conditions. DNA strand breaks caused by ROS lead to the activation of poly(ADP-ribose)polymerase-1 (PARP-1), the excessive activation of which can result in cell death. We have utilized a model in which 2,3,5-tris(glutathion-S-yl)hydroquinone (TGHQ), a nephrotoxic and nephrocarcinogenic metabolite of hydroquinone, causes ROS-dependent cell death in human renal proximal tubule epithelial cells (HK-2), to further elucidate the role of PARP-1 in ROS-dependent cell death. TGHQ-induced ROS generation, DNA strand breaks, hyperactivation of PARP-1, rapid depletion of nicotinamide adenine dinucleotide (NAD), elevations in intracellular Ca(2+) concentrations, and subsequent nonapoptotic cell death in both a PARP- and Ca(2+)-dependent manner. Thus, inhibition of PARP-1 with PJ34 completely blocked TGHQ-mediated accumulation of poly(ADP-ribose) polymers and NAD consumption, and delayed HK-2 cell death. In contrast, chelation of intracellular Ca(2+) with BAPTA completely abrogated TGHQ-induced cell death. Ca(2+) chelation also attenuated PARP-1 hyperactivation. Conversely, inhibition of PARP-1 modulated TGHQ-mediated changes in Ca(2+) homeostasis. Interestingly, PARP-1 hyperactivation was not accompanied by the translocation of apoptosis-inducing factor (AIF) from mitochondria to the nucleus, a process usually associated with PARP-dependent cell death. Thus, pathways coupling PARP-1 hyperactivation to cell death are likely to be context-dependent, and therapeutic strategies designed to target PARP-1 need to recognize such variability. Our studies provide new insights into PARP-1-mediated nonapoptotic cell death, during which PARP-1 hyperactivation and elevations in intracellular Ca(2+) are reciprocally coupled to amplify ROS-induced nonapoptotic cell death.

PubMed ID: 24752504 Exiting the NIEHS site

MeSH Terms: Calcium/metabolism*; Cell Culture Techniques; Cell Death/drug effects; Cell Line; Cell Survival/drug effects; Epithelial Cells/drug effects*; Epithelial Cells/metabolism; Epithelial Cells/pathology; Glutathione/analogs & derivatives*; Glutathione/toxicity; Humans; Hydroquinones/toxicity*; Kidney Tubules, Proximal/cytology; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases/metabolism*; Reactive Oxygen Species/metabolism*

Back
to Top