title: Pituitary adenylate cyclase activating polypeptide (PACAP) signalling exerts chondrogenesis promoting and protecting effects: implication of calcineurin as a downstream target.
abstract: Pituitary adenylate cyclase activating polypeptide (PACAP) is an important neurotrophic factor influencing differentiation of neuronal elements and exerting protecting role during traumatic injuries or inflammatory processes of the central nervous system. Although increasing evidence is available on its presence and protecting function in various peripheral tissues, little is known about the role of PACAP in formation of skeletal components. To this end, we aimed to map elements of PACAP signalling in developing cartilage under physiological conditions and during oxidative stress. mRNAs of PACAP and its receptors (PAC1,VPAC1, VPAC2) were detectable during differentiation of chicken limb bud-derived chondrogenic cells in micromass cell cultures. Expression of PAC1 protein showed a peak on days of final commitment of chondrogenic cells. Administration of either the PAC1 receptor agonist PACAP 1-38, or PACAP 6-38 that is generally used as a PAC1 antagonist, augmented cartilage formation, stimulated cell proliferation and enhanced PAC1 and Sox9 protein expression. Both variants of PACAP elevated the protein expression and activity of the Ca-calmodulin dependent Ser/Thr protein phosphatase calcineurin. Application of PACAPs failed to rescue cartilage formation when the activity of calcineurin was pharmacologically inhibited with cyclosporine A. Moreover, exogenous PACAPs prevented diminishing of cartilage formation and decrease of calcineurin activity during oxidative stress. As an unexpected phenomenon, PACAP 6-38 elicited similar effects to those of PACAP 1-38, although to a different extent. On the basis of the above results, we propose calcineurin as a downstream target of PACAP signalling in differentiating chondrocytes either in normal or pathophysiological conditions. Our observations imply the therapeutical perspective that PACAP can be applied as a natural agent that may have protecting effect during joint inflammation and/or may promote cartilage regeneration during degenerative diseases of articular cartilage.
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Debrecen, Faculty of Medicine, Debrecen, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Juhász
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Debrecen, Faculty of Medicine, Debrecen, Hungary.
authors.forename: Csaba
authors.initials: C
authors.lastname: Matta
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Debrecen, Faculty of Medicine, Debrecen, Hungary.
authors.forename: Éva
authors.initials: É
authors.lastname: Katona
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Debrecen, Faculty of Medicine, Debrecen, Hungary.
authors.forename: Csilla
authors.initials: C
authors.lastname: Somogyi
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Debrecen, Faculty of Medicine, Debrecen, Hungary.
authors.forename: Roland
authors.initials: R
authors.lastname: Takács
authors.affiliation: Cell Biology and Signalling Research Group of the Hungarian Academy of Sciences, Department of Medical Chemistry, Research Centre for Molecular Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
authors.forename: Pál
authors.initials: P
authors.lastname: Gergely
authors.affiliation: Department of Physiology, University of Debrecen, Faculty of Medicine, Debrecen, Hungary.
authors.forename: László
authors.initials: L
authors.lastname: Csernoch
authors.affiliation: Department of Biophysics and Cell Biology, University of Debrecen, Faculty of Medicine, Debrecen, Hungary.
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Panyi
authors.affiliation: Department of Medical Chemistry, University of Szeged, Faculty of Medicine, Szeged, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Tóth
authors.affiliation: Department of Anatomy PTE-MTA "Lendület" PACAP Research Team, University of Pécs, Medical School, Pécs, Hungary.
authors.forename: Dóra
authors.initials: D
authors.lastname: Reglődi
authors.affiliation: Department of Anatomy PTE-MTA "Lendület" PACAP Research Team, University of Pécs, Medical School, Pécs, Hungary.
authors.forename: Andrea
authors.initials: A
authors.lastname: Tamás
authors.affiliation: Department of Anatomy, Histology and Embryology, University of Debrecen, Faculty of Medicine, Debrecen, Hungary.
authors.forename: Róza
authors.initials: R
authors.lastname: Zákány
mesh_terms: D000818:Animals; D019703:Calcineurin / Q000235:genetics* / Q000378:metabolism; D065095:Calcineurin Inhibitors / Q000494:pharmacology; D002454:Cell Differentiation; D049109:Cell Proliferation; D002642:Chick Embryo; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D020219:Chondrogenesis / Q000235:genetics*; D016572:Cyclosporine / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D006861:Hydrogen Peroxide / Q000494:pharmacology; D018878:Limb Buds / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D018384:Oxidative Stress; D010455:Peptides / Q000138:chemical synthesis / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000138:chemical synthesis / Q000494:pharmacology*; D061251:Primary Cell Culture; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I / Q000235:genetics / Q000378:metabolism; D051239:Receptors, Vasoactive Intestinal Peptide, Type II / Q000235:genetics / Q000378:metabolism; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I / Q000235:genetics / Q000378:metabolism; D055758:SOX9 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D065095:Calcineurin Inhibitors; D010455:Peptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D055758:SOX9 Transcription Factor; D016572:Cyclosporine; D006861:Hydrogen Peroxide; D019703:Calcineurin