A new model of the distal convoluted tubule.
The Na(+)-Cl(-) cotransporter (NCC) in the distal convoluted tubule (DCT) of the kidney is a key determinant of Na(+) balance. Disturbances in NCC function are characterized by disordered volume and blood pressure regulation. However, many details concerning the mechanisms of NCC regulation remain controversial or undefined. This is partially due to the lack of a mammalian cell model of the DCT that is amenable to functional assessment of NCC activity. Previously reported investigations of NCC regulation in mammalian cells have either not attempted measurements of NCC function or have required perturbation of the critical without a lysine kinase (WNK)/STE20/SPS-1-related proline/alanine-rich kinase regulatory pathway before functional assessment. Here, we present a new mammalian model of the DCT, the mouse DCT15 (mDCT15) cell line. These cells display native NCC function as measured by thiazide-sensitive, Cl(-)-dependent (22)Na(+) uptake and allow for the separate assessment of NCC surface expression and activity. Knockdown by short interfering RNA confirmed that this function was dependent on NCC protein. Similar to the mammalian DCT, these cells express many of the known regulators of NCC and display significant baseline activity and dimerization of NCC. As described in previous models, NCC activity is inhibited by appropriate concentrations of thiazides, and phorbol esters strongly suppress function. Importantly, they display release of WNK4 inhibition of NCC by small hairpin RNA knockdown. We feel that this new model represents a critical tool for the study of NCC physiology. The work that can be accomplished in such a system represents a significant step forward toward unraveling the complex regulation of NCC.
Department of Medicine, University of Chicago, Chicago, Illinois, USA.
Benjamin
B
Ko
Abinash C
AC
Mistry
Lauren
L
Hanson
Rickta
R
Mallick
Leslie L
LL
Cooke
Bradley K
BK
Hack
Patrick
P
Cunningham
Robert S
RS
Hoover
D000818:Animals; D002460:Cell Line; D007686:Kidney Tubules, Distal / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D023421:Models, Animal; D017346:Protein Serine-Threonine Kinases / Q000494:pharmacology / Q000502:physiology; D049992:Sodium Chloride Symporters / Q000378:metabolism; D049971:Thiazides; D000099317:Hippo Kinases
D017346:Protein Serine-Threonine Kinases; D049992:Sodium Chloride Symporters; D049971:Thiazides; C499024:Prkwnk4 protein, mouse; C116037:PAS domain kinases; C402650:SLK protein, mouse; D000099317:Hippo Kinases