title: Continuous hydrostatic pressure induces differentiation phenomena in chondrocytes mediated by changes in polycystins, SOX9, and RUNX2.
abstract: OBJECTIVE
  The present study aimed to investigate the long-term effects of hydrostatic pressure on chondrocyte differentiation, as indicated by protein levels of transcription factors SOX9 and RUNX2, on transcriptional activity of SOX9, as determined by pSOX9 levels, and on the expression of polycystin-encoding genes Pkd1 and Pkd2.
  
  
  METHODS
  ATDC5 cells were cultured in insulin-supplemented differentiation medium (ITS) and/or exposed to 14.7 kPa of hydrostatic pressure for 12, 24, 48, and 96 h. Cell extracts were assessed for SOX9, pSOX9, and RUNX2 using western immunoblotting. The Pkd1 and Pkd2 mRNA levels were detected by real-time PCR.
  
  
  RESULTS
  Hydrostatic pressure resulted in an early drop in SOX9 and pSOX9 protein levels at 12 h followed by an increase from 24 h onwards. A reverse pattern was followed by RUNX2, which reached peak levels at 24 h of hydrostatic pressure-treated chondrocytes in ITS culture. Pkd1 and Pkd2 mRNA levels increased at 24 h of combined hydrostatic pressure and ITS treatment, with the latter remaining elevated up to 96 h.
  
  
  CONCLUSIONS
  Our data indicate that long periods of continuous hydrostatic pressure stimulate chondrocyte differentiation through a series of molecular events involving SOX9, RUNX2, and polycystins-1, 2, providing a theoretical background for functional orthopedic mechanotherapies.
authors.affiliation: Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 75, M. Asias Street, 11527, Athens, Greece.|Department of Orthodontics, Dental School, National and Kapodistrian University of Athens, 11527, Athens, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Karamesinis
authors.affiliation: Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 75, M. Asias Street, 11527, Athens, Greece.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Spyropoulou
authors.affiliation: Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 75, M. Asias Street, 11527, Athens, Greece.
authors.forename: Georgia
authors.initials: G
authors.lastname: Dalagiorgou
authors.affiliation: Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 75, M. Asias Street, 11527, Athens, Greece.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Katsianou
authors.affiliation: Section of Experimental Dento-Maxillo-Facial Medicine, University of Bonn, Welschnonnenstrasse 17, 53111, Bonn, Germany.
authors.forename: Marjan
authors.initials: M
authors.lastname: Nokhbehsaim
authors.affiliation: Department of Orthodontics Dento-Maxillo-Facial Medicine, University of Bonn, Welschnonnenstrasse 17, 53111, Bonn, Germany.
authors.forename: Svenja
authors.initials: S
authors.lastname: Memmert
authors.affiliation: Section of Experimental Dento-Maxillo-Facial Medicine, University of Bonn, Welschnonnenstrasse 17, 53111, Bonn, Germany.
authors.forename: James
authors.initials: J
authors.lastname: Deschner
authors.affiliation: Department of Orthodontics, Dental School, National and Kapodistrian University of Athens, 11527, Athens, Greece.
authors.forename: Heleni
authors.initials: H
authors.lastname: Vastardis
authors.affiliation: Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 75, M. Asias Street, 11527, Athens, Greece. cpiperi@med.uoa.gr.
authors.forename: Christina
authors.initials: C
authors.lastname: Piperi
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D019902:Chondrocytes / Q000166:cytology* / Q000502:physiology*; D020219:Chondrogenesis / Q000502:physiology; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D006874:Hydrostatic Pressure; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D051379:Mice; D055758:SOX9 Transcription Factor / Q000378:metabolism*; D013314:Stress, Mechanical
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; C493716:Runx2 protein, mouse; D055758:SOX9 Transcription Factor; C527933:Sox9 protein, mouse
keywords: Chondrocytes; Differentiation; Hydrostatic pressure; Polycystins; RUNX2; SOX9