title: Parathyroid hormone-related peptide regulation of chick tibial growth plate chondrocyte maturation requires protein kinase A.
abstract: Regulation of phenotype in chick tibial growth plate chondrocytes (GPCs) by parathyroid hormone-related peptide (PTHrP) is facilitated via signaling through three pathways: protein kinase A (PKA), protein kinase C (PKC) and inositol-1,4,5-trisphosphate-induced Ca2+ transients. To establish the underlying signaling specificity for PTHrP-regulation of chondrocyte maturation, we examined the separate involvement of each of these three pathways in the PTHrP regulation of key hallmarks of GPC phenotype: stimulation of proliferation and proteoglycan synthesis and reduction of alkaline phosphatase activity and type X collagen expression. Mimicking the PTHrP stimulation either of PKC with 1-oleoyl 2-acetyl glycerol or of a Ca2+ pulse with 65 mM KCl did not lead to PTHrP-like effects on any of the four markers examined. Also, inhibition of PKC with myr-psiPKC or blockade of Ca2+ signals with an intracellular chelator did not inhibit PTHrP action. However, PKA activation with dibutyryl cAMP mimicked PTHrP and blockade of PTHrP stimulation of PKA with H-89 inhibited the regulatory action of the factor. These data demonstrate that although activation of PKC or Ca2+ signals is not required, the cylic AMP-dependent A kinase is required for PTHrP to regulate key hallmarks of GPC phenotype.
authors.affiliation: Department of Orthopaedics, School of Medicine and Dentistry, University of Rochester, NY 14642, USA. michael_zuscik@urmc.rochester.edu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zuscik
authors.forename: Regis J
authors.initials: RJ
authors.lastname: O'Keefe
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Gunter
authors.forename: J Edward
authors.initials: JE
authors.lastname: Puzas
authors.forename: Edward M
authors.initials: EM
authors.lastname: Schwarz
authors.forename: Randy N
authors.initials: RN
authors.lastname: Rosier
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D002645:Chickens; D019902:Chondrocytes / Q000187:drug effects* / Q000201:enzymology; D024121:Collagen Type X / Q000235:genetics / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006132:Growth Plate / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D007546:Isoquinolines / Q000494:pharmacology; D044162:Parathyroid Hormone-Related Protein; D036361:Peptide Hormones / Q000494:pharmacology*; D011509:Proteoglycans / Q000096:biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D013449:Sulfonamides; D013977:Tibia / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development
chemical_list: D002614:Chelating Agents; D024121:Collagen Type X; D004791:Enzyme Inhibitors; D007546:Isoquinolines; D044162:Parathyroid Hormone-Related Protein; D036361:Peptide Hormones; D011509:Proteoglycans; D012333:RNA, Messenger; D013449:Sulfonamides; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D004533:Egtazic Acid; D003994:Bucladesine; D004247:DNA; D017868:Cyclic AMP-Dependent Protein Kinases; D000469:Alkaline Phosphatase; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D002118:Calcium