Integrin Expression and Osteopontin Regulation in Human Fetal Osteoblastic Cells Mediated by Substratum Surface Characteristics
- 1 January 2005
- journal article
- research article
- Published by Mary Ann Liebert Inc in Tissue Engineering
- Vol. 11 (1-2), 19-29
- https://doi.org/10.1089/ten.2005.11.19
Abstract
Integrin-mediated adhesion of anchorage-dependent cells to scaffolds is a critical component of tissue engineering. We investigated integrin expression by the human fetal osteoblastic cell line, hFOB 1.19 (hFOB), as a function of substratum surface wettability. The influence of surface wettability on bone cell phenotype was also examined. Plasma-treated quartz (PTQ) and glass (PTG) (hydrophilic, contact angles of 0°), octadecyltrichlorosilane-treated quartz (STQ) and glass (STG) (hydrophobic, contact angles above about 100°), and tissue culture polystyrene were used for cell culture. hFOB cells cultured on hydrophilic substrata displayed well-developed actin stress fibers relative to cells on hydrophobic substrata. Western blot analysis revealed that hFOB cells cultured on hydrophobic substrata (STQ or STG) express lower levels of αv and β3 integrin subunits than do cells on hydrophilic substrata (PTQ or PTG). This effect was more pronounced in cells on STQ than on STG. These variations in integrin expression were lessened by extended culture time. Double- labeled integrin/actin immunofluorescence confirmed Western blot results, that is, cells cultured on PTQ displayed distinct, large plaques of αv and β3 subunits and integrin αvβ3, as well as their colocalization with actin stress fiber ends, whereas cells on STQ did not display integrin plaques after 24 h and displayed only minimal plaque formation after 3 days. Vinculin, a focal adhesion protein that mediates binding between the integrin and actin cytoskeleton, appeared in Western blots to mimic the variations of αv and β3 expression with respect to surface wettability. Interestingly, real-time RT-PCR analysis showed that hFOB cultured on hydrophobic substrata, which have downregulated αv and β3 integrin subunits, displayed greater steady state mRNA levels of osteopontin, an extracellular matrix (ECM) protein containing the Arg-Gly-Asp (RGD) integrin recognition sequence, than did cells cultured on hydrophilic substrata. Our results imply that substratum surface wettability regulates integrin-mediated bone cell adhesion and further influences the expression of bone cell–ECM complexes.Keywords
This publication has 46 references indexed in Scilit:
- Poly(D,L-lactic acid)-Poly(ethylene glycol)-Monomethyl Ether Diblock Copolymers Control Adhesion and Osteoblastic Differentiation of Marrow Stromal CellsTissue Engineering, 2003
- Enhanced expression of the osteoblastic phenotype on substrates that modulate fibronectin conformation and integrin receptor bindingBiomaterials, 2002
- A Comparison of Type I Collagen, Fibronectin, and Vitronectin in Supporting Adhesion of Mechanically Strained OsteoblastsJournal of Bone and Mineral Research, 2002
- The regulation of growth and intracellular signaling by integrinsEndocrine Reviews, 1996
- Regulation of human osteoblast integrin expression by orthopedic implant materialsBone, 1996
- Integrins: Emerging Paradigms of Signal TransductionAnnual Review of Cell and Developmental Biology, 1995
- Tissue EngineeringScience, 1993
- Integrins: Versatility, modulation, and signaling in cell adhesionCell, 1992
- Complete nucleotide sequence of the region encompassing the first twenty-five exons of the human proα 1(I) collagen gene (COL1A1)Gene, 1988
- Integrins: A family of cell surface receptorsCell, 1987