Salt-losing nephropathy in mice with a null mutation of the Clcnk2 gene

Acta Physiol (Oxf). 2016 Nov;218(3):198-211. doi: 10.1111/apha.12755. Epub 2016 Aug 1.


Aim: The basolateral chloride channel ClC-Kb facilitates Cl reabsorption in the distal nephron of the human kidney. Functional mutations in CLCNKB are associated with Bartter's syndrome type 3, a hereditary salt-losing nephropathy. To address the function of ClC-K2 in vivo, we generated ClC-K2-deficient mice.

Methods: ClC-K2-deficient mice were generated using TALEN technology.

Results: ClC-K2-deficient mice were viable and born in a Mendelian ratio. ClC-K2-/- mice showed no gross anatomical abnormalities, but they were growth retarded. The 24-h urine volume was increased in ClC-K2-/- mice (4.4 ± 0.6 compared with 0.9 ± 0.2 mL per 24 h in wild-type littermates; P = 0.001). Accordingly, ambient urine osmolarity was markedly reduced (590 ± 39 vs. 2216 ± 132 mosmol L-1 in wild types; P < 0.0001). During water restriction (24 h), urinary osmolarity increased to 1633 ± 153 and 3769 ± 129 mosmol L-1 in ClC-K2-/- and wild-type mice (n = 12; P < 0.0001), accompanied by a loss of body weight of 12 ± 0.4 and 8 ± 0.2% respectively (P < 0.0001). ClC-K2-/- mice showed an increased renal sodium excretion and compromised salt conservation during a salt-restricted diet. The salt-losing phenotype of ClC-K2-/- mice was associated with a reduced plasma volume, hypotension, a slightly reduced glomerular filtration rate, an increased renal prostaglandin E2 generation and a massively stimulated renin-angiotensin system. Clckb-/- mice showed a reduced sensitivity to furosemide and were completely resistant to thiazides.

Conclusion: Loss of ClC-K2 compromises TAL function and abolishes salt reabsorption in the distal convoluted tubule. Our data suggest that ClC-K2 is crucial for renal salt reabsorption and concentrating ability. ClC-K2-deficient mice in most aspects mimic patients with Bartter's syndrome type 3.

Keywords: Bartter's syndrome; Clckb; chloride channels; gene targeting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bartter Syndrome / genetics*
  • Bartter Syndrome / metabolism
  • Bartter Syndrome / physiopathology
  • Chloride Channels / genetics*
  • Chloride Channels / metabolism
  • Dinoprostone / metabolism
  • Glomerular Filtration Rate / genetics
  • Kidney / metabolism
  • Kidney / physiopathology*
  • Mice
  • Mice, Knockout
  • Mutation*
  • Phenotype
  • Renin-Angiotensin System / genetics*


  • Chloride Channels
  • Clcnka protein, mouse
  • Dinoprostone