title: A mutation in TRPV4 results in altered chondrocyte calcium signaling in severe metatropic dysplasia.
abstract: Transient receptor potential cation channel, subfamily V, member 4 (TRPV4) is a polymodal modulated non-selective cation channel required for normal development and maintenance of bone and cartilage. Heterozygous mutations of this channel cause a variety of channelopathies, including metatropic dysplasia (MD). We analyzed the effect of a novel TRPV4 mutation c.2398G>A, p.Gly800Asp on intracellular calcium ([Ca(2+) ]i ) regulation in chondrocytes and compared this response to chondrocytes with a frequently observed mutation, c.2396C>T, p.Pro799Leu. We observed temperature-dependent [Ca(2+) ]i oscillations in both intact and MD chondrocytes however, MD mutations exhibited increased peak magnitudes of [Ca(2+) ]i during oscillations. We also found increased baseline [Ca(2+) ]i in MD primary cells, as well as increased [Ca(2+) ]i response to either hypotonic swelling or the TRVP4-specific agonist, GSK1016790A. Oscillations and stimulation responses were blocked with the TRPV4-specific antagonist, GSK205. Analysis of [Ca(2+) ]i response kinetics showed that MD chondrocytes had increased frequency of temperature-sensitive oscillations, and the magnitude and duration of [Ca(2+) ]i responses to given stimuli. Duration of the response of the p.Gly800Asp mutation to stimulation was greater than for the p.Pro799Leu mutation. These experiments show that this region of the channel is essential for proper [Ca(2+) ]i regulation. These studies of primary cells from patients show how both mutant and WT TRPV4 channels regulate cartilage and bone development. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, Delaware.|Molecular Diagnostics Laboratory, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware.
authors.forename: Lauren
authors.initials: L
authors.lastname: Hurd
authors.affiliation: Molecular Diagnostics Laboratory, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Kirwin
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, Delaware.
authors.forename: Mary
authors.initials: M
authors.lastname: Boggs
authors.affiliation: Department of Orthopaedic Surgery, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware.
authors.forename: William G
authors.initials: WG
authors.lastname: Mackenzie
authors.affiliation: Department of Orthopaedic Surgery, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware.|Division of Genetics, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Bober
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, Delaware.|Molecular Diagnostics Laboratory, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware.
authors.forename: Vicky L
authors.initials: VL
authors.lastname: Funanage
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, Delaware.
authors.forename: Randall L
authors.initials: RL
authors.lastname: Duncan
mesh_terms: D001842:Bone and Bones / Q000378:metabolism / Q000473:pathology; D002120:Calcium Channel Agonists / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling; D002356:Cartilage / Q000378:metabolism / Q000473:pathology; D002675:Child, Preschool; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D004392:Dwarfism / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D005260:Female; D015870:Gene Expression; D006801:Humans; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D009154:Mutation; D009997:Osmotic Pressure; D010009:Osteochondrodysplasias / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D010641:Phenotype; D061251:Primary Cell Culture; D012720:Severity of Illness Index; D013449:Sulfonamides / Q000494:pharmacology; D050916:TRPV Cation Channels / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism
chemical_list: D002120:Calcium Channel Agonists; D002121:Calcium Channel Blockers; C530602:N-(1-((4-(2-(((2,4-dichlorophenyl)sulfonyl)amino)-3-hydroxypropanoyl)-1-piperazinyl)carbonyl)-3-methylbutyl)-1-benzothiophene-2-carboxamide; D013449:Sulfonamides; D050916:TRPV Cation Channels; C416986:TRPV4 protein, human; D007930:Leucine
keywords: TRPV4; chondrocytes; intracellular calcium signaling; metatropic dysplasia