TY - JOUR
T1 - α-Ketoglutarate stimulates pendrin-dependent Cl- absorption in the mouse CCD through protein kinase C
AU - Lazo-Fernandez, Yoskaly
AU - Welling, Paul A.
AU - Wall, Susan M.
N1 - Funding Information:
This work was supported by National Institute of Diabetes and Digestive and Kidney Diseases Grants DK-110375 (project director: P. A. Welling; principal investigator: S. M. Wall). Y. Lazo-Fernandez was supported by a minority supplement to DK-104125 (to S. M. Wall).
Publisher Copyright:
© 2018 American Physiological Society. All rights reserved.
PY - 2018/7
Y1 - 2018/7
N2 - α-Ketoglutarate (α-KG) is a citric acid cycle intermediate and a glutamine catabolism product. It is also the natural ligand of 2-oxoglutarate receptor 1 (OXGR1), a Gq protein-coupled receptor expressed on the apical membrane of intercalated cells. In the cortical collecting duct (CCD), Cl-/HCO3 - exchange increases upon α-KG binding to the OXGR1. To determine the signaling pathway(s) by which α-KG stimulates Cl- absorption, we examined α-KG-stimulated Cl- absorption in isolated perfused mouse CCDs. α-KG increased electroneutral Cl- absorption in CCDs from wild-type mice but had no effect on Cl- absorption in pendrin knockout mice. Because Gq proteincoupled receptors activate PKC, we hypothesized that α-KG stimulates Cl- absorption through PKC. If so, PKC agonists should mimic, whereas PKC inhibitors should abolish, α-KG-stimulated Cl- absorption. Like α-KG, PKC agonist (phorbol-12,13-dibutyrate, 500 nM) application increased Cl- absorption in wild-type but not in pendrin null CCDs. Moreover, PKC inhibitors (2.5 mM GF109203X and 20 nM calphostin C), Ca2+ chelators (BAPTA, 10-20 µM), or PKC-α or -δ gene ablation eliminated α-KG-stimulated Cl- absorption. We have shown that STE20/SPS-1-related proline-alanine-rich protein kinase (SPAK) gene ablation increases urinary α-KG excretion, renal pendrin abundance, and CCD Cl- absorption. However, in SPAK null CCDs, Cl- absorption was not activated further by luminal α-KG application nor was Cl- absorption reduced with the PKC inhibitor GF109203. Thus SPAK gene ablation likely acts through a PKCindependent pathway to produce a chronic adaptive increase in pendrin function. In conclusion, α-KG stimulates pendrin-dependent Cl-/HCO3 - exchange through a mechanism dependent on PKC and Ca2+ that involves PKC-α and PKC-δ.
AB - α-Ketoglutarate (α-KG) is a citric acid cycle intermediate and a glutamine catabolism product. It is also the natural ligand of 2-oxoglutarate receptor 1 (OXGR1), a Gq protein-coupled receptor expressed on the apical membrane of intercalated cells. In the cortical collecting duct (CCD), Cl-/HCO3 - exchange increases upon α-KG binding to the OXGR1. To determine the signaling pathway(s) by which α-KG stimulates Cl- absorption, we examined α-KG-stimulated Cl- absorption in isolated perfused mouse CCDs. α-KG increased electroneutral Cl- absorption in CCDs from wild-type mice but had no effect on Cl- absorption in pendrin knockout mice. Because Gq proteincoupled receptors activate PKC, we hypothesized that α-KG stimulates Cl- absorption through PKC. If so, PKC agonists should mimic, whereas PKC inhibitors should abolish, α-KG-stimulated Cl- absorption. Like α-KG, PKC agonist (phorbol-12,13-dibutyrate, 500 nM) application increased Cl- absorption in wild-type but not in pendrin null CCDs. Moreover, PKC inhibitors (2.5 mM GF109203X and 20 nM calphostin C), Ca2+ chelators (BAPTA, 10-20 µM), or PKC-α or -δ gene ablation eliminated α-KG-stimulated Cl- absorption. We have shown that STE20/SPS-1-related proline-alanine-rich protein kinase (SPAK) gene ablation increases urinary α-KG excretion, renal pendrin abundance, and CCD Cl- absorption. However, in SPAK null CCDs, Cl- absorption was not activated further by luminal α-KG application nor was Cl- absorption reduced with the PKC inhibitor GF109203. Thus SPAK gene ablation likely acts through a PKCindependent pathway to produce a chronic adaptive increase in pendrin function. In conclusion, α-KG stimulates pendrin-dependent Cl-/HCO3 - exchange through a mechanism dependent on PKC and Ca2+ that involves PKC-α and PKC-δ.
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U2 - 10.1152/ajprenal.00576.2017
DO - 10.1152/ajprenal.00576.2017
M3 - Article
C2 - 29412702
AN - SCOPUS:85051112874
SN - 0363-6127
VL - 315
SP - F7-F15
JO - American Journal of Physiology - Renal Physiology
JF - American Journal of Physiology - Renal Physiology
IS - 1
ER -