title: Cyst formation following disruption of intracellular calcium signaling.
abstract: Mutations in polycystin 1 and 2 (PC1 and PC2) cause the common genetic kidney disorder autosomal dominant polycystic kidney disease (ADPKD). It is unknown how these mutations result in renal cysts, but dysregulation of calcium (Ca(2+)) signaling is a known consequence of PC2 mutations. PC2 functions as a Ca(2+)-activated Ca(2+) channel of the endoplasmic reticulum. We hypothesize that Ca(2+) signaling through PC2, or other intracellular Ca(2+) channels such as the inositol 1,4,5-trisphosphate receptor (InsP3R), is necessary to maintain renal epithelial cell function and that disruption of the Ca(2+) signaling leads to renal cyst development. The cell line LLC-PK1 has traditionally been used for studying PKD-causing mutations and Ca(2+) signaling in 2D culture systems. We demonstrate that this cell line can be used in long-term (8 wk) 3D tissue culture systems. In 2D systems, knockdown of InsP3R results in decreased Ca(2+) transient signals that are rescued by overexpression of PC2. In 3D systems, knockdown of either PC2 or InsP3R leads to cyst formation, but knockdown of InsP3R type 1 (InsP3R1) generated the largest cysts. InsP3R1 and InsP3R3 are differentially localized in both mouse and human kidney, suggesting that regional disruption of Ca(2+) signaling contributes to cystogenesis. All cysts had intact cilia 2 wk after starting 3D culture, but the cells with InsP3R1 knockdown lost cilia as the cysts grew. Studies combining 2D and 3D cell culture systems will assist in understanding how mutations in PC2 that confer altered Ca(2+) signaling lead to ADPKD cysts.
authors.affiliation: Departments of Pharmacology and.
authors.forename: Ivana Y
authors.initials: IY
authors.lastname: Kuo
authors.affiliation: Department of Biomedical Engineering, School of Engineering, Tufts University, Medford, MA 02155.
authors.forename: Teresa M
authors.initials: TM
authors.lastname: DesRochers
authors.affiliation: Department of Biomedical Engineering, School of Engineering, Tufts University, Medford, MA 02155.
authors.forename: Erica P
authors.initials: EP
authors.lastname: Kimmerling
authors.affiliation: Departments of Pharmacology and.
authors.forename: Lily
authors.initials: L
authors.lastname: Nguyen
authors.affiliation: Departments of Pharmacology and Cellular and Molecular Physiology, School of Medicine, Yale University, New Haven, CT 06520; and barbara.ehrlich@yale.edu david.kaplan@tufts.edu.
authors.forename: Barbara E
authors.initials: BE
authors.lastname: Ehrlich
authors.affiliation: Department of Biomedical Engineering, School of Engineering, Tufts University, Medford, MA 02155 barbara.ehrlich@yale.edu david.kaplan@tufts.edu.
authors.forename: David L
authors.initials: DL
authors.lastname: Kaplan
mesh_terms: D000818:Animals; D020013:Calcium Signaling; D018929:Cell Culture Techniques; D002923:Cilia / Q000378:metabolism / Q000473:pathology; D003470:Culture Media; D055785:Gene Knockdown Techniques; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D018374:LLC-PK1 Cells; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation; D016891:Polycystic Kidney, Autosomal Dominant / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D013552:Swine; D050396:TRPP Cation Channels / Q000172:deficiency / Q000235:genetics / Q000378:metabolism
chemical_list: D003470:Culture Media; D053496:Inositol 1,4,5-Trisphosphate Receptors; D050396:TRPP Cation Channels
keywords: calcium release; polycysin 2; primary cilia