title: Urocortin is a novel regulator of osteoclast differentiation and function through inhibition of a canonical transient receptor potential 1-like cation channel.
abstract: This study investigated the role of urocortin (UCN), a member of the corticotrophin-releasing factor (CRF) family of peptides, in osteoclast maturation and function. We found that 10(-7) M UCN significantly (P<0.05) suppressed osteoclast differentiation from bone marrow precursor cells in culture and reduced the expression of several osteoclastic markers. Furthermore, UCN potently suppressed osteoclast bone resorption, by significantly inhibiting both the plan area of bone resorbed by osteoclasts and actin ring formation within osteoclasts at 10(-9) M (P<0.05), with complete inhibition at 10(-7) M (P<0.001). UCN also inhibited osteoclast motility (10(-7) M) but had no effect on osteoclast survival. Osteoclasts expressed mRNA encoding both UCN and the CRF receptor 2β subtype. Pre-osteoclasts however, expressed CRF receptor 2β alone. Unstimulated osteoclasts contained constitutively active cation channel currents with a unitary conductance of 3-4 pS, which were inhibited by over 70% with UCN (10(-7) M). Compounds that regulate calcium signalling and energy status of the cell, both crucial for osteoclast activity were investigated. The non-selective cation channel blockers, lanthanum (La(3)(+)) and gadolinium (Gd(3)(+)), inhibited actin ring formation in osteoclasts, whereas modulators of voltage-dependent Ca(2)(+) channels and K(ATP) channels had no effect. These findings show for the first time that UCN is a novel anti-resorptive molecule that acts through a direct effect on osteoclasts and their precursor cells.
authors.affiliation: Department of Cellular Pathology, St George's, University of London, Cranmer Terrace, London SW17 ORE, UK.
authors.forename: Charlotte E
authors.initials: CE
authors.lastname: Combs
authors.forename: Karen
authors.initials: K
authors.lastname: Fuller
authors.forename: Hashethra
authors.initials: H
authors.lastname: Kumar
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Albert
authors.forename: Grisha
authors.initials: G
authors.lastname: Pirianov
authors.forename: James
authors.initials: J
authors.lastname: McCormick
authors.forename: Ian C
authors.initials: IC
authors.lastname: Locke
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Chambers
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Lawrence
mesh_terms: D016475:3T3 Cells; D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D000831:Animals, Newborn; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D001862:Bone Resorption / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control; D001842:Bone and Bones / Q000166:cytology / Q000648:ultrastructure; D020013:Calcium Signaling; D002417:Cattle; D002454:Cell Differentiation; D002465:Cell Movement; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D049990:Membrane Transport Modulators / Q000494:pharmacology; D051379:Mice; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D012333:RNA, Messenger / Q000378:metabolism; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D050052:TRPC Cation Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D054832:Urocortins / Q000235:genetics / Q000378:metabolism*
chemical_list: C101531:CRF receptor type 2; D049990:Membrane Transport Modulators; D012333:RNA, Messenger; D018019:Receptors, Corticotropin-Releasing Hormone; D050052:TRPC Cation Channels; C549377:Ucn1 protein, mouse; D054832:Urocortins; C096351:transient receptor potential cation channel, subfamily C, member 1