Collagen-mimetic peptides (CMPs) for integrin-specific cellular recognition and tissue engineering

Abstract

This study demonstrated the significant progress in the use of a collagen-mimetic peptide (CMP) for its ability to elicit specific cellular responses, particularly integrin-mediated cell adhesion and signaling pathways. In this study, CMPs containing residues 502-507 (Glycine-Phenylalanine- Hydroxyproline-Glycine-Glutamate-Arginine) (GFOGER) of collagen α1 (I) were tested for interactions with Hep3B liver cells. Recognition of these biomolecules by the cells appeared 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 adhesion of Hep3B cells to collagen in a competition assay, suggesting the cell binding to these CMPs involves specific collagen integrin-receptors. The cell adhesion activity of the CMP1 was about 50% of that of collagen, verifying the GFOGER as the major binding locus of the type I collagen. The cell spreading morphology on the CMP1 was comparable to that observed on the collagen. The effect of the CMP1 on regulating cell morphology, proliferation and functions was examined by Hep3B cell culture on the CMP1-functionalized Poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) microspheres. The presence of the CMP1 matrix promoted cell attachment and spreading on the microspheres as well as extensive cell growth and cellular bridging as demonstrated by the total DNA content and thick tissue-like construct (thickness >100 μm). A three-dimensional distribution of CMP1 ligands on the microspheres improved albumin secretion and P-450 activity of the cells. Our results established the potential of the CMP1 to replace the native collagen in the matrix biology and tissue engineering applications. It can be used as a tool for specific cell-integrin targeting for optimizing cellular responses as well as improving cellular phenotypes and functions.