TY - JOUR
T1 - Distal convoluted tubule Cl-concentration is modulated via K+ channels and transporters
AU - Su, Xiao Tong
AU - Klett, Nathan J.
AU - Sharma, Avika
AU - Allen, Charles N.
AU - Wang, Wen Hui
AU - Yang, Chao Ling
AU - Ellison, David H.
N1 - Funding Information:
We thank Dr. P. Bregestovski for kindly providing the Cre-inducible Rosa26::Cl-Sensor mice. This work was supported by National Institutes of Health (NIH) Grant DK054196 (to D. H. Ellison and C. L. Yang), Veterans Affairs Grant 1I01BX002228 and a Fondation LeDucq Transatlantic Network of Excellence grant (to D. H. Ellison), NIH Grant DK54983 (to W.-H. Wang and D. H. Ellison), NIH Grants NS036607 and NS103842 (to C. N. Allen), a KidneyCure Ben J. Lipps post doc fellowship (to X.-T. Su), and NIH Grant T32DK067864 (to N. J. Klett).
Publisher Copyright:
© 2020 American Physiological Society. All rights reserved.
PY - 2020/9
Y1 - 2020/9
N2 - Cl-sensitive with-no-lysine kinase (WNK) plays a key role in regulating the thiazide-sensitive Na+-Cl- cotransporter (NCC) in the distal convoluted tubule (DCT). Cl- enters DCT cells through NCC and leaves the cell across the basolateral membrane via the Cl- channel ClC-K2 or K+-Cl- cotransporter (KCC). While KCC is electroneutral, Cl- exit via ClC-K2 is electrogenic. Therefore, an alteration in DCT basolateral K+ channel activity is expected to influence Cl- movement across the basolateral membrane. Although a role for intracellular Cl- in the regulation of WNK and NCC has been established, intracellular Cl- concentrations ([Cl-]i) have not been directly measured in the mammalian DCT. Therefore, to measure [Cl-]i in DCT cells, we generated a transgenic mouse model expressing an optogenetic kidney-specific Cl-Sensor and measured Cl- fluorescent imaging in the isolated DCT. Basal measurements indicated that the mean [Cl-]i was ~7 mM. Stimulation of Cl- exit with low-Cl- hypotonic solutions decreased [Cl-]i, whereas inhibition of KCC by DIOA or inhibition of ClC-K2 by NPPB increased [Cl-]i, suggesting roles for both KCC and ClC-K2 in the modulation of [Cl-]i. Blockade of basolateral K+ channels (Kir4.1/5.1) with barium significantly increased [Cl-]i. Finally, a decrease in extracellular K+ concentration transiently decreased [Cl-]i, whereas raising extracellular K+ transiently increased [Cl-]i, further suggesting a role for Kir4.1/5.1 in the regulation of [Cl-]i. We conclude that the alteration in ClC-K2, KCC, and Kir4.1/5.1 activity influences [Cl-]i in the DCT.
AB - Cl-sensitive with-no-lysine kinase (WNK) plays a key role in regulating the thiazide-sensitive Na+-Cl- cotransporter (NCC) in the distal convoluted tubule (DCT). Cl- enters DCT cells through NCC and leaves the cell across the basolateral membrane via the Cl- channel ClC-K2 or K+-Cl- cotransporter (KCC). While KCC is electroneutral, Cl- exit via ClC-K2 is electrogenic. Therefore, an alteration in DCT basolateral K+ channel activity is expected to influence Cl- movement across the basolateral membrane. Although a role for intracellular Cl- in the regulation of WNK and NCC has been established, intracellular Cl- concentrations ([Cl-]i) have not been directly measured in the mammalian DCT. Therefore, to measure [Cl-]i in DCT cells, we generated a transgenic mouse model expressing an optogenetic kidney-specific Cl-Sensor and measured Cl- fluorescent imaging in the isolated DCT. Basal measurements indicated that the mean [Cl-]i was ~7 mM. Stimulation of Cl- exit with low-Cl- hypotonic solutions decreased [Cl-]i, whereas inhibition of KCC by DIOA or inhibition of ClC-K2 by NPPB increased [Cl-]i, suggesting roles for both KCC and ClC-K2 in the modulation of [Cl-]i. Blockade of basolateral K+ channels (Kir4.1/5.1) with barium significantly increased [Cl-]i. Finally, a decrease in extracellular K+ concentration transiently decreased [Cl-]i, whereas raising extracellular K+ transiently increased [Cl-]i, further suggesting a role for Kir4.1/5.1 in the regulation of [Cl-]i. We conclude that the alteration in ClC-K2, KCC, and Kir4.1/5.1 activity influences [Cl-]i in the DCT.
KW - Chloride
KW - Chloride channel
KW - K+-Cl- cotransporter
KW - Na+-Cl- cotransporter
KW - Potassium channel
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U2 - 10.1152/ajprenal.00284.2020
DO - 10.1152/ajprenal.00284.2020
M3 - Article
C2 - 32715757
AN - SCOPUS:85090277962
VL - 319
SP - F534-F540
JO - American journal of physiology. Renal physiology
JF - American journal of physiology. Renal physiology
SN - 0363-6127
IS - 3
ER -