title: TRPV6 channel modulates proliferation of insulin secreting INS-1E beta cell line.
abstract: Transient receptor potential channel vanilloid type 6 (TRPV6) is a non-selective cation channel with high permeability for Ca²⁺ ions. So far, the role of TRPV6 in pancreatic beta cells is unknown. In the present study, we characterized the role of TRPV6 in controlling calcium signaling, cell proliferation as well as insulin expression, and secretion in experimental INS-1E beta cell model. TRPV6 protein production was downregulated using siRNA by approx. 70%, as detected by Western blot. Intracellular free Ca²⁺ ([Ca²⁺]i) was measured by fluorescence Ca²⁺ imaging using fura-2. Calcineurin/NFAT signaling was analyzed using a NFAT reporter assay as well as a calcineurin activity assay. TRPV6 downregulation resulted in impaired cellular calcium influx. Its downregulation also reduced cell proliferation and decreased insulin mRNA expression. These changes were companied by the inhibition of the calcineurin/NFAT signaling. In contrast, insulin exocytosis was not affected by TRPV6 downregulation. In conclusion, this study demonstrates for the first time the expression of TRPV6 in INS-1E cells and rat pancreatic beta cells and describes its role in modulating calcium signaling, beta cell proliferation and insulin mRNA expression. In contrast, TRPV6 fails to influence insulin secretion.
authors.affiliation: Department of Hepatology and Gastroenterology & the Interdisciplinary Centre of Metabolism: Endocrinology, Diabetes and Metabolism, Charité-University Medicine Berlin, 13353 Berlin, Germany; Department of Animal Physiology and Biochemistry,Poznań University of Life Sciences, 60-637Poznań, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Skrzypski
authors.affiliation: Institute for Experimental Pediatric Endocrinology, Charite-University-Medicine Berlin, 13353Berlin, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Khajavi
authors.affiliation: Department of Ophthalmology, Charité-University Medicine Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Mergler
authors.affiliation: Department of Animal Physiology and Biochemistry,Poznań University of Life Sciences, 60-637Poznań, Poland.
authors.forename: D
authors.initials: D
authors.lastname: Szczepankiewicz
authors.affiliation: Department of Hepatology and Gastroenterology & the Interdisciplinary Centre of Metabolism: Endocrinology, Diabetes and Metabolism, Charité-University Medicine Berlin, 13353 Berlin, Germany; Department of Animal Physiology and Biochemistry,Poznań University of Life Sciences, 60-637Poznań, Poland.
authors.forename: P A
authors.initials: PA
authors.lastname: Kołodziejski
authors.affiliation: Department of Hepatology and Gastroenterology & the Interdisciplinary Centre of Metabolism: Endocrinology, Diabetes and Metabolism, Charité-University Medicine Berlin, 13353 Berlin, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Metzke
authors.affiliation: Department of Animal Physiology and Biochemistry,Poznań University of Life Sciences, 60-637Poznań, Poland.
authors.forename: T
authors.initials: T
authors.lastname: Wojciechowicz
authors.affiliation: Department of Animal Physiology and Biochemistry,Poznań University of Life Sciences, 60-637Poznań, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Billert
authors.affiliation: Department of Animal Physiology and Biochemistry,Poznań University of Life Sciences, 60-637Poznań, Poland.
authors.forename: K W
authors.initials: KW
authors.lastname: Nowak
authors.affiliation: Department of Hepatology and Gastroenterology & the Interdisciplinary Centre of Metabolism: Endocrinology, Diabetes and Metabolism, Charité-University Medicine Berlin, 13353 Berlin, Germany; Medical Clinic 1, Elblandklinik, 01662Meissen, Germany. Electronic address: mathias.strowski@charite.de.
authors.forename: M Z
authors.initials: MZ
authors.lastname: Strowski
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000502:physiology*; D006706:Homeostasis; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007340:Insulinoma / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D051381:Rats; D050916:TRPV Cation Channels / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D007328:Insulin; D050916:TRPV Cation Channels; C120776:TRPV6 channel; D002118:Calcium
keywords: Beta cell; Calcium; Insulin; Proliferation; TRPV; TRPV6