Either integrin subunit β1 or β3 is involved in mediating monocyte adhesion, IL-1β protein and mRNA expression in response to surfaces functionalized with fibronectin-derived peptides

We synthesized gelatin-based, interpenetrating network (IPN) scaffolds immobilized with fibronectin (FN)-derived peptides to assess monocyte-biomaterial interaction. Human primary monocytes were seeded onto peptide-grafted IPN or tissue-culture polystyrene (TCPS) pre-adsorbed with FN or FN-derived peptides. Monocyte cell density on both TCPS and IPN surfaces was higher in the presence of the arginine-glycine-aspartic acid (RGD) peptide. Pretreatment with anti-integrin beta 1 or beta 3 antibody decreased monocyte density on all ligand-modified TCPS and IPN. Interleukin-1 beta (IL-1 beta) protein levels of cells on modified TCPS decreased over time. IL-1 beta expression of monocytes in the presence of IPNs peaked at 24 h and then decreased through 168 h. Ligand identity did not affect IL-1 beta expression in either TCPS or IPN samples. Pretreatment with anti-integrin beta 1 or beta 3 antibody reduced IL-1 beta levels from both TCPS and IPN samples in a ligand-independent manner, particularly at 24 h. Monocytic IL-1 beta mRNA expression in IPN samples without antibody pretreatment was highest at 2 h and decreased over time. IL-1 beta mRNA expression in cells with anti-integrin beta 1 or beta 3 antibody pretreatment was similar to those without antibody pretreatment, except for methoxygrafted IPN samples. The change in IL-1 beta mRNA expression did not correlate with changes in protein expression. The results indicate that monocyte adhesion was affected by the substrate and the RGD sequence and beta 1 or beta 3 containing integrin receptors. beta 1-or beta 3-containing integrin receptors were also involved in IL-1 beta gene and protein expression in monocytes adhered to gelatin-based biomaterial surfaces.