Evolutionarily conserved sequence motif analysis guided development of chemically defined hydrogels for therapeutic angiogenesis. Evolutionarily conserved sequence motif analysis guided development of chemically defined hydrogels for therapeutic angiogenesis

Biologically ligands (e.g., RGDS from fibronectin: Fn-RGD) play a critical role in the development of chemically defined biomaterials. However, there has been limited progress in recent decades towards discovering novel extracellular-matrix-protein-derived ligands for translational applications. Here, by combining motif analysis of evolutionarily conserved RGD-containing regions in laminin (Ln) with functional microarray screening, we identified a Ln-derived angiogenic peptide (LDAP) that showed enhanced proangiogenic activities over commonly used Fn-RGD. Mechanistic studies using RNA-sequencing of LDAP functionalized hydrogels showed an improved angiogenic transcriptome over Fn-RGD functionalized hydrogels and high similarity to Matrigel, attributed to the ability of LDAP to engage both Ln- and Fn-binding integrins. Injectable hydrogels functionalized with LDAP, along with MMP-QK (a VEGF-mimetic peptide), exhibited increased functional recovery over decellularized extracellular matrix (dECM) and alginates functionalized with Fn-RGD and MMP-QK in a mouse ischemic hindlimb model, illustrating the power of the strategy to rapidly develop potent chemically-defined biomaterials for therapeutic applications. Overall design: HUVECs (p2-p3) were encapsulated into 0.125mmol/g peptide-modified alginate (at alginate concentration = 1% (w/v)) at the density of 2 million cells/mL with EGM for 24 hours. Groups include HUVECs cultured in LDAP(laminin derived angiogenic peptide)-peptide modified alginate compared to in RGDS-peptide modified alginate hydrogels.