Faculty Collaboration Database

Voltage gated proton channels modulate mitochondrial reactive oxygen species production by complex I in renal medullary thick ascending limb. Redox Biol 2019 Oct;27:101191

Date

05/08/2019

Pubmed ID

31060879

Pubmed Central ID

PMC6859587

DOI

10.1016/j.redox.2019.101191

Scopus ID

2-s2.0-85064987982 (requires institutional sign-in at Scopus site)   7 Citations

Abstract

Hv1 is a voltage-gated proton channel highly expressed in immune cells where, it acts to maintain NAD(P)H oxidase activity during the respiratory burst. We have recently reported that Hv1 is expressed in cells of the medullary thick ascending limb (mTAL) of the kidney and is critical to augment reactive oxygen species (ROS) production by this segment. While Hv1 is associated with NOX2 mediated ROS production in immune cells, the source of the Hv1 dependent ROS in mTAL remains unknown. In the current study, the rate of ROS formation was quantified in freshly isolated mTAL using dihydroethidium and ethidium fluorescence. Hv1 dependent ROS production was stimulated by increasing bath osmolality and ammonium chloride (NH₄Cl) loading. Loss of either p67phox or NOX4 did not abolish the formation of ROS in mTAL. Hv1 was localized to mitochondria within mTAL, and the mitochondrial superoxide scavenger mitoTEMPOL reduced ROS formation. Rotenone significantly increased ROS formation and decreased mitochondrial membrane potential in mTAL from wild-type rats, while treatment with this inhibitor decreased ROS formation and increased mitochondrial membrane potential in mTAL from Hv1^-/- mutant rats. These data indicate that NADPH oxidase is not the primary source of Hv1 dependent ROS production in mTAL. Rather Hv1 localizes to the mitochondria in mTAL and modulates the formation of ROS by complex I. These data provide a potential explanation for the effects of Hv1 on ROS production in cells independent of its contribution to maintenance of cell membrane potential and intracellular pH.

Author List

Patel B, Zheleznova NN, Ray SC, Sun J, Cowley AW Jr, O'Connor PM

Author

Allen W. Cowley Jr PhD Professor in the Physiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Electron Transport Complex I
Female
Ion Channels
Loop of Henle
Male
Membrane Potential, Mitochondrial
Mitochondria
NADPH Oxidase 2
Oxidation-Reduction
Protons
Rats
Reactive Oxygen Species
Respiratory Burst
Rotenone
Superoxides