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Sci Rep. 2017 Mar 21;7:45032. doi: 10.1038/srep45032.

Signalling mechanisms mediating Zn2+-induced TRPM2 channel activation and cell death in microglial cells.

Author information

1
School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, United Kingdom.
2
School of Life Sciences, University of Manchester, United Kingdom.
3
School of Molecular and Cell Biology, Faculty of Biological Sciences, University of Leeds, United Kingdom.
4
Sino-UK Joint Laboratory of Brain Function and Injury, and Department of Physiology and Neurobiology, Xinxiang Medical University, PR China.

Abstract

Excessive Zn2+ causes brain damage via promoting ROS generation. Here we investigated the role of ROS-sensitive TRPM2 channel in H2O2/Zn2+-induced Ca2+ signalling and cell death in microglial cells. H2O2/Zn2+ induced concentration-dependent increases in cytosolic Ca2+ concentration ([Ca2+]c), which was inhibited by PJ34, a PARP inhibitor, and abolished by TRPM2 knockout (TRPM2-KO). Pathological concentrations of H2O2/Zn2+ induced substantial cell death that was inhibited by PJ34 and DPQ, PARP inhibitors, 2-APB, a TRPM2 channel inhibitor, and prevented by TRPM2-KO. Further analysis indicate that Zn2+ induced ROS production, PARP-1 stimulation, increase in the [Ca2+]c and cell death, all of which were suppressed by chelerythrine, a protein kinase C inhibitor, DPI, a NADPH-dependent oxidase (NOX) inhibitor, GKT137831, a NOX1/4 inhibitor, and Phox-I2, a NOX2 inhibitor. Furthermore, Zn2+-induced PARP-1 stimulation, increase in the [Ca2+]c and cell death were inhibited by PF431396, a Ca2+-sensitive PYK2 inhibitor, and U0126, a MEK/ERK inhibitor. Taken together, our study shows PKC/NOX-mediated ROS generation and PARP-1 activation as an important mechanism in Zn2+-induced TRPM2 channel activation and, TRPM2-mediated increase in the [Ca2+]c to trigger the PYK2/MEK/ERK signalling pathway as a positive feedback mechanism that amplifies the TRPM2 channel activation. Activation of these TRPM2-depenent signalling mechanisms ultimately drives Zn2+-induced Ca2+ overloading and cell death.

PMID:
28322340
PMCID:
PMC5359577
DOI:
10.1038/srep45032
[Indexed for MEDLINE]
Free PMC Article

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