title: Differentiation of human mesenchymal stem cells and articular chondrocytes: analysis of chondrogenic potential and expression pattern of differentiation-related transcription factors.
abstract: Mesenchymal stem cells (MSCs) are a candidate for replacing chondrocytes in cell-based repair of cartilage lesions. However, it has not been clarified if these cells can acquire the hyaline phenotype, and whether chondrocytes and MSCs show the same expression patterns of critical control genes in development. In order to study this, articular chondrocytes and iliac crest derived MSCs were allowed to differentiate in pellet mass cultures. Gene expression of markers for the cartilage phenotype, helix-loop-helix (HLH) transcription factors, and chondrogenic transcription factors were analyzed by real-time PCR. Matrix production was assayed using biochemical analysis for hydroxyproline, glycosaminoglycans, and immunohistochemistry for collagen types I and II. Significantly decreased expression of collagen type I was accompanied by increased expression of collagen types IIA and IIB during differentiation of chondrocytes, indicating differentiation towards a hyaline phenotype. Chondrogenesis in MSCs on the other hand resulted in up-regulation of collagen types I, IIA, IIB, and X, demonstrating differentiation towards cartilage of a mixed phenotype. Expression of HES1 increased significantly during chondrogenesis in chondrocytes while expression in MSCs was maintained at a low level. The HLH gene HES5 on the other hand was only detected in chondrocytes. Expression of ID1 decreased significantly in chondrocytes while the opposite was seen in MSCs. These findings suggest that chondrocytes and MSCs differentiated and formed different subtypes of cartilage, the hyaline and a mixed cartilage phenotype, respectively. Differentially regulated HLH genes indicated the possibility for HLH proteins in regulating chondrogenic differentiation. This information is important to understand the potential use of MSCs in cartilage repair.
authors.affiliation: Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska University Hospital, Gothenburg University, Göteborg, Sweden.
authors.forename: Camilla
authors.initials: C
authors.lastname: Karlsson
authors.forename: Camilla
authors.initials: C
authors.lastname: Brantsing
authors.forename: Teresia
authors.initials: T
authors.lastname: Svensson
authors.forename: Helena
authors.initials: H
authors.lastname: Brisby
authors.forename: Julia
authors.initials: J
authors.lastname: Asp
authors.forename: Tommi
authors.initials: T
authors.lastname: Tallheden
authors.forename: Anders
authors.initials: A
authors.lastname: Lindahl
mesh_terms: D000328:Adult; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000502:physiology; D020219:Chondrogenesis / Q000235:genetics / Q000502:physiology*; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D024121:Collagen Type X / Q000235:genetics / Q000378:metabolism; D005434:Flow Cytometry / Q000379:methods; D005786:Gene Expression Regulation / Q000502:physiology*; D018257:Helix-Loop-Helix Motifs / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D051798:Inhibitor of Differentiation Protein 1 / Q000235:genetics / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology; D008875:Middle Aged; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000072056:Transcription Factor HES-1; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D024042:Collagen Type I; D024121:Collagen Type X; D018398:Homeodomain Proteins; D051798:Inhibitor of Differentiation Protein 1; D012097:Repressor Proteins; D000072056:Transcription Factor HES-1; D014157:Transcription Factors; C497453:ID1 protein, human; C077478:HES5 protein, human; C078493:HES1 protein, human