title: Calcium phosphate and calcium oxalate crystal handling is dependent upon CLC-5 expression in mouse collecting duct cells.
abstract: Defects in an intracellular chloride channel CLC-5 cause Dent's disease, an inherited kidney stone disorder. Using a collecting duct model, mIMCD-3 cells, we show expression of dimeric mCLC-5. Transient transfection of antisense CLC-5 reduces CLC-5 protein expression. Binding of both calcium phosphate (hydroxyapatite) and calcium oxalate monohydrate (COM) crystals overlaid onto mIMCD-3 cultures was affected by altered CLC-5 expression. Calcium phosphate crystal agglomerations (>10 microm) were minimal in control (9%) and sense (13%) CLC-5-transfected cells, compared to 66% of antisense CLC-5-transfected cells (P<0.001). Small calcium phosphate crystals (<10 microm) were found associated with 45% of sense CLC-5-treated cells, of which the majority (11/14 cells) appeared to be internalised within the cell. Calcium oxalate agglomerations (>10 microm) were also largely absent for controls or sense mCLC-5 transfectants (11% and 9% of cells, respectively) with COM crystal agglomerates predominating in antisense CLC-5 transfectants (66%, P<0.0001). We conclude that collecting duct cells with reduced CLC-5 expression lead to a tendency to form calcium crystal agglomeration, which may help explain the nephrocalcinosis and nephrolithiasis seen in Dent's disease.
authors.affiliation: School of Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, NE2 4HH, UK. j.a.sayer@ncl.ac.uk
authors.forename: J A
authors.initials: JA
authors.lastname: Sayer
authors.forename: G
authors.initials: G
authors.lastname: Carr
authors.forename: N L
authors.initials: NL
authors.lastname: Simmons
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002129:Calcium Oxalate / Q000737:chemistry* / Q000378:metabolism*; D002130:Calcium Phosphates / Q000737:chemistry* / Q000378:metabolism*; D002460:Cell Line; D018118:Chloride Channels / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D003460:Crystallization; D005786:Gene Expression Regulation; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000378:metabolism*; D051379:Mice
chemical_list: C097503:CLC-5 chloride channel; D002130:Calcium Phosphates; D018118:Chloride Channels; D002129:Calcium Oxalate; C020243:calcium phosphate