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National Institute of Environmental Health Sciences

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Your Environment. Your Health.

Publication Detail

Title: From the Cover: ROS-Induced Store-Operated Ca2+ Entry Coupled to PARP-1 Hyperactivation Is Independent of PARG Activity in Necrotic Cell Death.

Authors: Munoz, Frances M; Zhang, Fengjiao; Islas-Robles, Argel; Lau, Serrine S; Monks, Terrence J

Published In Toxicol Sci, (2017 Aug 01)

Abstract: 2,3,5-tris(Glutathion-S-yl)hydroquinone, a potent nephrotoxic and nephrocarcinogenic metabolite of benzene and hydroquinone, generates reactive oxygen species (ROS) causing DNA strand breaks and the subsequent activation of DNA repair enzymes, including poly(ADP-ribose) polymerase (PARP)-1. Under robust oxidative DNA damage, PARP-1 is hyperactivated, resulting in the depletion of NAD+ and ATP with accompanying elevations in intracellular calcium concentrations (iCa2+), and ultimately necrotic cell death. The role of Ca2+ during PARP-dependent necrotic cell death remains unclear. We therefore sought to determine the relationship between Ca2+ and PARP-1 during ROS-induced necrotic cell death in human renal proximal tubule epithelial cells (HK-2). Our experiments suggest that store-operated Ca2+ channel (SOC) entry contributes to the coupling of PARP-1 activation to increases in iCa2+ during ROS-induced cell death. Poly(ADP-ribose)glycohydrolase (PARG), which catalyzes the degradation of PARs to yield free ADP-ribose (ADPR), is known to activate Ca2+ channels such as TRPM2. However, siRNA knockdown of PARG did not restore cell viability, indicating that free ADPR is not responsible for SOC activation in HK-2 cells. The data indicate that PARP-1 and iCa2+ are coupled through activation of SOC mediated Ca2+ entry in an apparently ADPR-independent fashion; alternative PAR-mediated signaling likely contributes to PARP-dependent necrotic cell death, perhaps via PAR-mediated signaling proteins that regulate iCa2+ homeostasis.

PubMed ID: 28525621 Exiting the NIEHS site

MeSH Terms: Calcium/metabolism*; Cell Death*; Cell Line; Cells, Cultured; Glutathione/analogs & derivatives; Glutathione/toxicity; Glycoside Hydrolases/metabolism*; Humans; Hydroquinones/toxicity; Ion Transport; Necrosis; Oxidation-Reduction; Poly (ADP-Ribose) Polymerase-1/metabolism*; Reactive Oxygen Species/metabolism*

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