College

The Graduate School

Program

Biomedical Sciences

Publication Date

4-1-2021

Abstract

Nano-Pulse Stimulation (NPS), a pulsed power-derived technology, stimulates structural and functional changes in plasma membranes and cellular organelles. NPS induces a Ca2+ influx and opening of the mitochondrial permeability transition pore (mPTP) that dissipates the mitochondrial membrane potential (ΔΨm) and, when sustained, induces regulated cell death. Here we show that in rat cardiomyoblasts (H9C2) cyclophilin D (CypD) is a mitochondrial sensor for NPS as defined by observations that loss of ΔΨm is Ca2+ and mitochondrial reactive oxygen species (mROS) dependent and cyclosporin A (CsA)-sensitive, which are diagnostic qualities for effects on CypD and the mPTP. Mechanistically, NPS stimulates increases in intracellular Ca2+ which enhances mROS in a dose dependent manner. The regulatory role of CypD on mPTP activation, is effectively inhibited at low Ca2+ concentrations and/or by CsA. Although NPS-induced dissipation of ΔΨm is largely Ca2+-dependent, the degree of Ca2+ sensitivities vary among cell types. Nevertheless, knockdown of the proapoptotic protein, APAF-1, and overexpression of the antiapoptotic protein, Bcl-xl, in human Jurkat T lymphocytes (E6.1) did not affect NPS-induced dissipation of ΔΨm or cell death. Taken together, these results indicate NPS induces activation of the mPTP through Ca2+-dependent, mROS-dependent, CsA-sensitive dissipation of the ΔΨm that is independent of caspase activation and insensitive to protection by Bcl-xl.

Disciplines

Biomedical Engineering and Bioengineering | Cell Biology | Molecular Biology

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Cyclophilin D Is a Sensor of Nano-Pulse Stimulation


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