title: In vitro analysis of differential expression of collagens, integrins, and growth factors in cultured human chondrocytes.
abstract: OBJECTIVE
  Tissue engineering represents a promising method for the construction of autologous chondrogenic grafts for reconstructive surgery. In cultured chondrocytes, the dedifferentiation and proliferation of the cells are critical factors that influence the generation of transplants. The aim of our study was to find and characterize markers for cell proliferation and dedifferentiation in cultured chondrocytes.
  
  
  METHODS
  Human chondrocytes were isolated from septal cartilage and held in primary cell culture. Cells were harvested after 1, 6, and 21 days. The differentiation of the cells was investigated with bright-field microscopy, the expression patterns of various proteins using immunohistochemistry, and the expression of distinct genes with the microarray technique.
  
  
  RESULTS
  The chondrocytes showed a strong proliferation. After 6 and 21 days, collagen 9 and 10 were downregulated; collagen 11 was activated. Collagen 1 and 2 were downregulated after 6 days but were reactivated after 21 days. Tumor growth factor beta (TGF-beta)1 was strongly expressed on days 1, 6, and 21, TGF-beta2 was never expressed, and TGF-beta3 and -beta4 were upregulated from day 1 to day 21. The TGF-beta receptor III was expressed on days 1, 6, and 21. Integrin beta1, beta5, and alpha5 were upregulated from day 1 to day 21; integrin beta3 was downregulated.
  
  
  CONCLUSIONS
  Collagens 3, 4, 8, 9, and 11 might be new markers for the dedifferentiation of chondrocytes. Collagen 2 might be a marker for the synthetic activity of the cells rather than the dedifferentiation. TGF-beta3 and -beta4 might influence the dedifferentiation, which is fortified by the expression of TGF-beta receptor III. Integrin beta1, beta5, and alpha5 might be involved in signal transmission for the dedifferentiation.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Red Cross Blood Service of Baden-Württemberg/Hessen, Ruprecht-Karls-University Heidelberg, Theodor-Kutzer-Ufer, D-68135 Mannheim, Germany. ullrich.goessler@hno.ma.uni-heidelberg.de
authors.forename: Ulrich Reinhart
authors.initials: UR
authors.lastname: Goessler
authors.forename: Peter
authors.initials: P
authors.lastname: Bugert
authors.forename: Karen
authors.initials: K
authors.lastname: Bieback
authors.forename: Haneen
authors.initials: H
authors.lastname: Sadick
authors.forename: Alexander
authors.initials: A
authors.lastname: Baisch
authors.forename: Karl
authors.initials: K
authors.lastname: Hormann
authors.forename: Frank
authors.initials: F
authors.lastname: Riedel
mesh_terms: D015415:Biomarkers / Q000032:analysis; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism*; D003094:Collagen / Q000032:analysis*; D024042:Collagen Type I / Q000032:analysis; D024043:Collagen Type II / Q000032:analysis; D024081:Collagen Type IX / Q000032:analysis; D024121:Collagen Type X / Q000032:analysis; D024161:Collagen Type XI / Q000032:analysis; D015536:Down-Regulation; D006133:Growth Substances / Q000032:analysis*; D006801:Humans; D039482:Integrin alpha5 / Q000032:analysis; D039641:Integrin beta Chains / Q000032:analysis; D019012:Integrin beta1 / Q000032:analysis; D039661:Integrin beta3 / Q000032:analysis; D016023:Integrins / Q000032:analysis*; D011509:Proteoglycans / Q000032:analysis; D018125:Receptors, Transforming Growth Factor beta / Q000032:analysis; D016212:Transforming Growth Factor beta / Q000032:analysis; D053773:Transforming Growth Factor beta1; D053782:Transforming Growth Factor beta3; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D024043:Collagen Type II; D024081:Collagen Type IX; D024121:Collagen Type X; D024161:Collagen Type XI; D006133:Growth Substances; D039482:Integrin alpha5; D039641:Integrin beta Chains; D019012:Integrin beta1; D039661:Integrin beta3; D016023:Integrins; D011509:Proteoglycans; D018125:Receptors, Transforming Growth Factor beta; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D053782:Transforming Growth Factor beta3; C084344:integrin beta5; C445082:transforming growth factor beta4; C071736:betaglycan; D003094:Collagen