title: Integrin expression in stem cells from bone marrow and adipose tissue during chondrogenic differentiation.
abstract: The use of adult mesenchymal stem cells (MSC) in cartilage tissue engineering offers new perspectives in the generation of transplants for reconstructive surgery. The extracelular matrix (ECM) plays a key role in modulating the function and phenotype of the embedded cells and contains the integrins as adhesion receptors mediating cell-cell and cell-matrix interactions. In our study, characteristic changes in integrin expression during the course of chondrogenic differentiation of MSC from bone marrow and adipose tissue were compared. MSC were isolated from bone marrow biopsies and adipose tissue. During cell culture, chondrogenic differentiation was performed. The expression of integrins and their signaling components were analysed with microarray and immunohistochemistry in freshly isolated MSC and after chondrogenic differentiation. The fibronectin receptor (integrin alpha5beta1) was expressed by undifferentiated MSC, and expression rose during chondrogenic differentiation in both types of MSC. The components of the vitronectin/osteopontin receptors (alphavbeta5) were not expressed by freshly isolated MSC, and expression rose with ongoing differentiation. Receptors for the collagens (alpha1beta1, alpha2beta1, alpha3beta1) were weakly expressed by undifferentiated MSC and were activated during differentiation. Intracellular signaling components integrin-linked kinase (ILK) and CD47 showed increased expression with ongoing differentiation. For all integrins, no significant differences were be found in the 2 types of MSC. Integrin-mediated signaling appeared to play an important role in the generation and maintenance of the chondrocytic phenotype during chondrogenic differentiation. Particularly, the receptors for fibronectin, vitronectin, osteopontin and the collagens may be involved in the generation of the ECM. Intracellularly, their signals might be transduced by ILK and CD47. To fully harness the potential of these cells, future studies should be directed to ascertain their cellular and molecular characteristics for optimal identification, isolation, and expansion.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, University Hospital Mannheim, Mannheim, Germany. ulrich.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: Jens
authors.initials: J
authors.lastname: Stern-Straeter
authors.forename: Gregor
authors.initials: G
authors.lastname: Bran
authors.forename: Karl
authors.initials: K
authors.lastname: Hörmann
authors.forename: Frank
authors.initials: F
authors.lastname: Riedel
mesh_terms: D000273:Adipose Tissue / Q000166:cytology* / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001854:Bone Marrow Cells / Q000166:cytology* / Q000378:metabolism; D002454:Cell Differentiation; D002469:Cell Separation; D002478:Cells, Cultured; D020219:Chondrogenesis; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D016023:Integrins / Q000235:genetics / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D012984:Software
chemical_list: D016023:Integrins