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Alpha‐ketoglutarate stimulates Cl − absorption in the mouse CCD through a mechanism dependent on pendrin and protein kinase C
Author(s) -
Fernandez Yoskaly Lazo,
Welling Paul A,
Wall Susan M
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.857.19
Subject(s) - pendrin , absorption (acoustics) , chemistry , calphostin c , protein kinase c , biochemistry , biophysics , signal transduction , biology , transporter , materials science , composite material , gene
Alpha‐ketoglutarate (aKG) is an intermediary of the citric acid cycle that binds to its G‐protein coupled receptor, OXGR1, in the apical membrane of the kidney type B and non‐A‐non‐B intercalated cells of the cortical collecting duct (CCD) which increases Cl − /HCO 3 − exchange in the CCD. To determine the intracellular signaling pathways by which aKG stimulates Cl − absorption, we examined aKG‐stimulated Cl − absorption in CCDs perfused in vitro that were taken from mice eating a standard rodent diet. Since pendrin is the major mechanism of apical Cl − /HCO 3 − exchange in type B intercalated cells, we asked if aKG‐stimulated Cl − absorption is pendrin‐dependent. To do so, we compared the effect of aKG on Cl − absorption in CCDs from pendrin null mice and their wild type littermates. aKG increased Cl − absorption in CCDs from wild type mice without changing transepithelial voltage, V T . However aKG had no effect on Cl − absorption in CCDs from pendrin KO mice. Because aKG's receptor in the type B IC, OXGR1, acts through a Gq‐mediated pathway, we asked if aKG stimulates Cl − absorption through PKC‐dependent signaling. To do so, we examined the effect of aKG on Cl − absorption in the presence of two structurally distinct PKC inhibitors (2.5 mM GF 109203X and 20 nM Calphostin C) or their vehicle. We observed that PKC inhibitor application to the bath solution eliminated aKG‐stimulated Cl − absorption. Moreover, PKCa gene ablation eliminated aKG‐stimulated Cl − absorption. To determine if aKG stimulates Cl − absorption through a Ca 2+ ‐dependent mechanism, we examined the effect of aKG on Cl − absorption with the Ca 2+ ‐chelator bapta (20 μM) or vehicle in the bath solution. We observed that this Ca 2+ chelator eliminated the increment in Cl − absorption observed with aKG application. We conclude that aKG stimulates pendrin‐dependent Cl − /HCO 3 − exchange through a PKC‐ and Ca 2+ ‐dependent mechanism that involves, at least in part, the PKCa isoform. Support or Funding Information This study was supported by National Institute of Diabetes and Digestive and Kidney Diseases grants DK‐46493 (to S. M. Wall and T32 DK‐07656 to Y. Lazo‐Fernandez.