Aldosterone modulates thiazide-sensitive sodium chloride cotransporter abundance via DUSP6-mediated ERK1/2 signaling pathway

Abstract

modulates thiazide-sensitive sodium chloride cotransporter abundance via DUSP6-mediated ERK1/2 signaling pathway. Am J Physiol Renal Physiol 308: F1119 -F1127, 2015. First published March 11, 2015 doi:10.1152/ajprenal.00543.2014.-Thiazide-sensitive sodium chloride cotransporter (NCC) plays an important role in maintaining blood pressure. Aldosterone is known to modulate NCC abundance. Previous studies reported that dietary salts modulated NCC abundance through either WNK4 [with no lysine (k) kinase 4]-SPAK (Ste20-related proline alanine-rich kinase) or WNK4-extracellular signalregulated kinase-1 and -2 (ERK1/2) signaling pathways. To exclude the influence of SPAK signaling pathway on the role of the aldosterone-mediated ERK1/2 pathway in NCC regulation, we investigated the effects of dietary salt changes and aldosterone on NCC abundance in SPAK knockout (KO) mice. We found that in SPAK KO mice low-salt diet significantly increased total NCC abundance while reducing ERK1/2 phosphorylation, whereas high-salt diet decreased total NCC while increasing ERK1/2 phosphorylation. Importantly, exogenous aldosterone administration increased total NCC abundance in SPAK KO mice while increasing DUSP6 expression, an ERK1/2-specific phosphatase, and led to decreasing ERK1/2 phosphorylation without changing the ratio of phospho-T53-NCC/total NCC. In mouse distal convoluted tubule (mDCT) cells, aldosterone increased DUSP6 expression while reducing ERK1/2 phosphorylation. DUSP6 Knockdown increased ERK1/2 phosphorylation while reducing total NCC expression. Inhibition of DUSP6 by (E)-2-benzylidene-3-(cyclohexylamino)-2,3-dihydro-1H-inden-1-one increased ERK1/2 phosphorylation and reversed the aldosterone-mediated increments of NCC partly by increasing NCC ubiquitination. Therefore, these data suggest that aldosterone modulates NCC abundance via altering NCC ubiquitination through a DUSP6-dependent ERK1/2 signal pathway in SPAK KO mice and part of the effects of dietary salt changes may be mediated by aldosterone in the DCTs. aldosterone; dietary salt; sodium chloride cotransporter; dual-specificity protein phosphatase 6; ERK1/2; SPAK KO mice THE THIAZIDE-SENSITIVE SODIUM chloride cotransporter (NCC), located in the apical membrane of the distal convoluted tubule (DCT) of the kidney, is responsible for 5-7% of sodium reabsorption (6). NCC plays a key role in the regulation of blood pressure and electrolytes homeostasis (6, 12). Loss-offunction mutations in NCC have been reported to cause Gitelman's syndrome (GS), which is characterized by salt-wasting and low blood pressure (15). NCC is known to be modulated by two different types of regulation, type 1-altering its membrane expression, and type 2-altering the transporter kinetics (17).Aldosterone has been shown to increase the thiazide-sensitive NCC protein in rats (20). Previous studies reported that the regulation of NCC by aldosterone is mediated through a WNK4 [with no lysine (k) kinase 4]-SPAK (Ste20-related proline alanine-rich kinase)-dependent pathway in response to the di...

The thiazide sensitive sodium chloride co-transporter NCC is modulated by site-specific ubiquitylation

“…The greater plasma membrane abundance, combined with reduced internalization rate of the studied mutants, when expressed in MDCKI cells, strengthens the current concept that NCC ubiquitylation, in part, is important for modulating NCC endocytosis 17 , 18 , 22 , 23 . What remains unclear is whether the K706, K828, and K909 sites act alone or together in modulating NCC membrane levels.…”

“…In general, ubiquitylation can target NCC for endoplasmic reticulum-associated degradation (ERAD) by the Hsp70/Hsp40 chaperone system and the C terminus of Hsp70-interacting protein (CHIP) 15 , 16 . Increased NCC ubiquitylation following phorbol ester treatment 17 was associated with increased NCC endocytosis, whereas decreased ubiquitylation though a dual-specificity protein phosphatase (DUSP)6-dependent ERK1/2 signal pathway 18 increased NCC membrane abundance. The ubiquitin-protein ligase NEDD4-2 is implicated in NCC ubiquitylation, as modulation of NEDD4-2 function in vitro or in vivo modulates NCC abundance and plasma membrane levels 19 , 20 .…”

A novel function of calcitonin gene-related peptide in body fluid Cl−homeostasis

“…Most studies on CGRP in mammals have not been directly related to body fluid ionic homeostasis [30]. Angiotensin II and aldosterone exert their actions on blood pressure though control of NCC in the renal DCT epithelia cells [9,10,31,32] and thus the possibility that CGRP also targets NCC cannot be ruled out. On the other hand, some recent studies in fish suggested a possible involvement of CGRP in iono-and osmoregulation.…”

Stimulatory Role of SPAK Signaling in the Regulation of Large Conductance Ca2+-Activated Potassium (BK) Channel Protein Expression in Kidney

“…WNK kinase is also known to phosphorylate SPAK kinase to activate the SPAK signaling pathway. In SPAK KO mice, ERK 1/2 phosphorylation is enhanced (Feng et al, 2015). We therefore hypothesized that SPAK kinase might affect BK protein expression by modulating ERK 1/2 phosphorylation.…”

“…SPAK not only participates in the regulation of ion channels (Falin et al, 2011;Warsi et al, 2014c;Ahmed et al, 2015) but also regulates a variety of carriers, including NaCl (NCC) and Na + -K + -2Cl − (NKCC) cotransporters, KCl symporters, and Na + /H + exchangers (Delpire and Gagnon, 2006;Gagnon et al, 2006;Vitari et al, 2006;Geng et al, 2009;Gagnon and Delpire, 2010). In previous studies, we showed that multiple members of the WNK family regulate BK protein expression via the ERK1/2 pathway (Zhuang et al, 2011;Liu et al, 2015) or explored the effects of SPAK and ERK1/2 in the NCC regulation process in the WNK family (Zhou et al, 2012;Feng et al, 2015;Wang et al, 2016). Although SPAK is widely expressed in the renal tubules, the link between SPAK and BK remains largely unknown.…”