title: The role of transglutaminase 2 and osteopontin in matrix protein supplemented microencapsulation of marrow stromal cells.
abstract: Previous studies reported that matrix protein supplementation (fibronectin/fibrinogen, FN/FG) of agarose gel microcapsules enhances survival and target tissue retention of syngeneic rat marrow stromal cells (MSCs). We hypothesized that additional supplementation of microcapsules with osteopontin (OPN) and transglutaminase 2 (TG2) would enhance cell survival, while stabilizing the provisional matrix. Using monomeric OPN or OPN polymerized with TG2, we examined human MSC adhesion, morphology, focal contact formation and apoptosis. Polymeric OPN with TG2 induced greater adhesion than monomeric OPN (84.5 ± 10.7 vs. 44.3 ± 10.0 cells/field), and also significantly enhanced focal contact formation (351.5 ± 21.2 vs. 45.6 ± 17.6 focal contact sites/cell) and cell spreading (2.7 × 10(3) ± 0.20 × 10(3) μm(2) vs. 1.2 × 10(3) ± 0.26 × 10(2) μm(2)) while preserving MSC pluripotency. Microcapsules supplemented with FN/FG, polymeric OPN and TG2 demonstrated significantly less apoptotic cells than FN/FG microcapsules (14.0 ± 2.34% vs. 28.2 ± 3.22%). Reduced apoptosis was attributed to matrix stabilization by TG2 and the synergistic activity of matrix proteins. It is anticipated that this enhanced survival will maximize the therapeutic potential of MSCs.
authors.affiliation: The Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada.
authors.forename: Nazanin
authors.initials: N
authors.lastname: Hakimzadeh
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Stewart
authors.forename: David W
authors.initials: DW
authors.lastname: Courtman
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001854:Bone Marrow Cells / Q000166:cytology*; D002448:Cell Adhesion / Q000187:drug effects / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D019204:GTP-Binding Proteins / Q000494:pharmacology*; D006801:Humans; D053495:Osteopontin / Q000737:chemistry / Q000494:pharmacology*; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011503:Transglutaminases / Q000494:pharmacology*
chemical_list: C000717609:Tgm2 protein, rat; D053495:Osteopontin; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins