Insights into type III collagen α1 chain remodeling: Mechanisms of enhanced cell adhesion in wound healing

Collagen in the extracellular matrix interacts with cells and plays a pivotal role in integrin-mediated physiological processes. However, current collagen materials rely on peptides, bacterial collagen-like polymers, or tandemly repeating collagen domains, which fail to replicate the full-length native collagen structure with complete functional motifs. In this study, full-length single chain α1(III) collagen (COL3A1) was redesigned to preserve natural bioactivity. Four evenly distributed motifs along the chain were substituted with non-native GFPGER sequences (GR1). Based on GR1, five native integrin-binding sites were replaced with the GFPGER sequence, which has higher affinity for integrin α₂β₁, resulting in nine total substitutions (GR2). Using the Pichia pastoris expression system, GR1 and GR2 proteins demonstrated proper in vivo stability based on melting temperature (T_m) analysis. Wound healing applications were evaluated via structural characterization, cell adhesion assays, molecular docking, and animal studies. GR2, with more extensive motif substitutions, exhibited superior biological activities compared to COL3A1 and GR1, including enhanced cell adhesion, improved angiogenesis, and accelerated wound healing. These novel collagen proteins show great potential for tissue engineering and wound repair and provide a customizable collagen material platform for diverse biomedical applications.