An integrin-specific collagen-mimetic peptide approach for optimizing Hep3B liver cell adhesion, proliferation, and cellular functions

This study focused on mimicking collagen structurally and biologically using various peptide sequences toward realizing an artificial collagen-like biomaterial. Collagen-mimetic peptides (CMPs) incorporating integrin-specific glycine-phenylalanine-hydroxyproline-glycine-glutamate-arginine (GFOGER) sequence from residues 502 to 507 of collagen alpha(1)(I) were used as a bioadhesive matrix and grafted onto poly(3-hydroxybutyrate-co3- hydroxyvalerate) microspheres to optimize cell adhesion, proliferation, and functions. Cell recognition of these biomolecules appeared to be conformation dependent, with the CMP1 of higher triple helix stability being preferred. Absence of the GFOGER hexapeptide in the CMP1' and CMP2' caused an adverse effect on the level of cell adhesion (< 10%). The GFOGER-containing triple-helical CMPs effectively inhibited cell adhesion to collagen in a competition assay. The cell-adhesion activity of the CMP1 was approximately 50% of that of collagen. The cell spreading on the CMP1 was comparable with that observed on collagen. The presence of the CMP1 promoted cell attachment and spreading on the microspheres and extensive cell proliferation and bridging. Slower cell proliferation was observed on the blank microspheres. Live-dead assay showed that most cells are viable after 10-day culture. The presence of CMP1 on the microspheres maintained the albumin secretion and P-450 activity levels of the liver cells for up to 14 days. Our results established the potential of CMP1 to create a collagenlike microenvironment for optimizing cellular responses for liver tissue engineering.