How Bartter's and Gitelman's syndromes, and Dent's disease have provided important insights into the function of three renal chloride channels: ClC-Ka/b and ClC-5.
Chloride channels are expressed in almost all cell membranes and are potentially involved in a wide variety of functions. The kidney expresses 8 of the 9 chloride channels of the ClC family that have been cloned so far to date in mammals. This review focuses on the pathophysiology of two renal disorders that have contributed recently to our understanding of the physiological role of chloride channels belonging to the ClC family. First are the related syndromes of Bartter's and Gitelman's, in which inactivating mutations of the genes encoding either of the ClC-Ks, or their regulatory beta-subunit barttin, have shown the important contribution of these chloride channels to renal tubular sodium and chloride (NaCl) transport along the loop of Henle and distal tubule. Second is the renal Fanconi syndrome known as Dent's disease, in which ClC-5 disruption has revealed the key role of this endosomal chloride channel in the megalin-mediated endocytotic pathway in the proximal tubule. The underlying pathophysiology of this inherited disorder demonstrates how ClC-5 is directly or indirectly required for the reabsorption of filtered low-molecular-weight proteins and bioactive peptides, also expression of membrane transporters, and clearance of calcium-based stone-forming crystals.
Briet
Marie
M
Départementde Physiologie, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris; INSERM U.356, IFR 58, and Rene Descartes University and School of Medicine, Paris, France.
Vargas-Poussou
Rosa
R
Lourdel
Stephane
S
Houillier
Pascal
P
Blanchard
Anne
A
D000818:Animals; D001477:Bartter Syndrome / Q000378:metabolism* / Q000503:physiopathology*; D018118:Chloride Channels / Q000502:physiology*; D006801:Humans; D007674:Kidney Diseases / Q000378:metabolism* / Q000503:physiopathology
C097503:CLC-5 chloride channel; C489932:CLCNKA protein, human; C412733:CLCNKB protein, human; D018118:Chloride Channels