Effects of nsPEFs on Electron Transport and Mitochondrial Structures and Functions
Document Type
Abstract
Publication Date
11-7-2024
DOI
10.25776/1wp2-ct10
Abstract
Nanosecond pulsed electric fields (nsPEFs) are a pulsed power technology known for ablating tumors, but they can also modulate diverse biological mechanisms. NsPEFs enhanced trans-plasma membrane electron transport (tPMET) rates at lower charging levels and attenuated rates at higher charging levels. NsPEFs attenuated electron transport (ET) (O2 consumption) in the electron transport chain (ETC) of intact and permeabilized cells as well as in isolated mitochondria at Complex I when coupled and uncoupled to oxidative phosphorylation. Effects on isolated mitochondria disclosed possible direct nsPEF effects on mitochondria. Effects of nsPEFs on increases in mROS were synergistic with the complex I inhibitor rotenone, tendering that nsPEFs and rotenone act at different sites in the ETC. Other studies showed that Ca2+ enhanced and cyclosporin A (CsA) attenuated the loss of mitochondrial membrane potential (ΔΨm) but CsA did not prevent cell death, suggesting some limited role for cyclophilin D (CypD). A calcein and CoCl2 assay indicated that, unlike ionomycin, nsPEFs did not open the mitochondria permeability transition pore (mPTP). Exploring physical effects of nsPEFs on mitochondria, cytochrome c and NADH were used as impermeable molecules to the outer (OMM) and inner mitochondrial membrane (IMM), respectively. After nsPEF exposure, cytochrome c, but not NADH, caused a significant oxygen flux in permeabilized cells, demonstrating that nsPEFs caused a disruption the OMM but not the IMM. Given that nsPEFs did not electro-permeabilize the IMM nor open the mPTP, we considered that the adenine nucleotide translocator (ANT) may be involved at least in the slower current of the mPTP but neither bongkrekic acid (BKA) nor atractyloside (ATR) had an effect, ruling out ANT in a mechanism for the nsPEF-induced loss of ΔΨm. Overall, nsPEFs have distinct structural effects even on isolated mitochondria disrupting the OMM but not the IMM yet attenuating electron transport by a mechanism distinct from that of rotenone in complex I and dissipating the ΔΨm by a mechanism attenuated by CypD but not through a well determined structure.
Repository Citation
Beebe, Stephen J.; Asadipour, Kamal; Ruedinger, Britney; Potter, Lucas; Hooker, Teresa; and Lai, Nicola, "Effects of nsPEFs on Electron Transport and Mitochondrial Structures and Functions" (2024). 2024 Frank Reidy Research Center for Bioelectrics Retreat. 13.
https://digitalcommons.odu.edu/bioelectrics-2024retreat/13
