Faculty Collaboration Database

ROS production as a common mechanism of ENaC regulation by EGF, insulin, and IGF-1. Am J Physiol Cell Physiol 2013 Jan 01;304(1):C102-11

Date

11/09/2012

Pubmed ID

23135700

Pubmed Central ID

PMC3543576

DOI

10.1152/ajpcell.00231.2012

Scopus ID

2-s2.0-84871909495 (requires institutional sign-in at Scopus site)   53 Citations

Abstract

The epithelial Na(+) channel (ENaC) is a key transporter participating in the fine tuning of Na(+) reabsorption in the nephron. ENaC activity is acutely upregulated by epidermal growth factor (EGF), insulin, and insulin-like growth factor-1 (IGF-1). It was also proposed that reactive oxygen species (ROS) have a stimulatory effect on ENaC. Here we studied whether effects of EGF, insulin, and IGF-1 correlate with ROS production in the mouse cortical collecting duct (mpkCCD(c14)) cells. Western blotting confirmed the expression of the NADPH oxidase complex subunits in these cells. Treatment of mpkCCD(c14) cells with EGF, insulin, or IGF-1 evoked an increase in ROS production as measured by CM-H(2)DCF-DA fluorescence. ROS production caused by a xanthine-xanthine oxidase reaction also resulted in a significant elevation in short-circuit current through the mpkCCD(c14) monolayer. Transepithelial current measurements showed an acute increase of amiloride-sensitive current through the mpkCCD(c14) monolayer in response to EGF, insulin, or IGF-1. Pretreatment with the nonselective NADPH oxidase activity inhibitor apocynin blunted both ROS production and increase in ENaC-mediated current in response to these drugs. To further test whether NADPH oxidase subunits are involved in the effect of EGF, we used a stable M-1 cell line with a knockdown of Rac1, which is one of the key subunits of the NADPH oxidase complex, and measured amiloride-sensitive currents in response to EGF. In contrast to control cells, EGF had no effect in Rac1 knockdown cells. We hypothesize that EGF, insulin, and IGF-1 have a common stimulatory effect on ENaC mediated by ROS production.

Author List

Ilatovskaya DV, Pavlov TS, Levchenko V, Staruschenko A

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

Animals
Cell Line, Transformed
Epidermal Growth Factor
Epithelial Sodium Channels
Hypoglycemic Agents
Insulin
Insulin-Like Growth Factor I
Kidney Tubules, Collecting
Mice
Neuropeptides
Oxidative Stress
Reactive Oxygen Species
rac GTP-Binding Proteins
rac1 GTP-Binding Protein