title: Gene regulation of extracellular matrix remodeling in human bone marrow stem cell-seeded tissue-engineered grafts.
abstract: Tissue-engineered heart valves are prone to early structural deterioration. We hypothesize that cell-scaffold interaction and mechanical deformation results in upregulation of genes related to osteogenic/chondrogenic differentiation and thus changes extracellular matrix (ECM) composition in human bone marrow mesenchymal stem cell (hBMSC)-derived tissue-engineered grafts. hBMSC were expanded and seeded onto poly-glycolic acid/poly-lactic acid scaffold for 14 days. Seeded tissue-engineered constructs (TEC) were subjected to cyclic flexure for 24 h, whereas control TEC was maintained in roller bottles for the same duration. hBMSC, TEC, and mechanically deformed TEC were subjected to gene-array and histological analysis. Expression levels of RNA and/or protein markers related to chondrogenesis (Sox9, MGP, RunX2, Col II, Col X, and Col XI) and osteogenesis (ALPL, BMP2, EDN1, RunX1, and Col I) were increased in TEC compared to unseeded hBMSC. Histological sections of TEC stained positive for Saffranin O, alkaline phosphatase activity, and calcium deposits. The expression levels of the above gene and protein markers further increased in deformed TEC compared to static TEC. Cell-scaffold interactions and mechanical stress results in gene expression suggestive of endochondral-ossification that impact upon ECM composition and may predispose them to eventual calcification.
authors.affiliation: Cardiac Surgery, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Sirisha
authors.initials: S
authors.lastname: Emani
authors.forename: John E
authors.initials: JE
authors.lastname: Mayer
authors.forename: Sitaram M
authors.initials: SM
authors.lastname: Emani
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000166:cytology* / Q000378:metabolism; D002478:Cells, Cultured; D016000:Cluster Analysis; D005109:Extracellular Matrix / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D010641:Phenotype; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D013314:Stress, Mechanical; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*; D015854:Up-Regulation / Q000235:genetics
chemical_list: D000469:Alkaline Phosphatase