A Surrozen Inc. research team has reported preclinical data for the novel frizzled class receptor 4 (FZD4) agonist, SZN-413, being evaluated for the treatment of diabetic retinopathy. In vitro studies using the Norrin mimetic (SZN-413-p) revealed that SZN-413-p induced Wnt/β-catenin signaling and upregulated blood-brain barrier/blood-retina barrier gene expressions in endothelial cells.