423F

423F (also known as RCGD-423F or MPA-1) is a small molecule glycoprotein 130 (gp130) modulator and signal transducer and activator of transcription 3 (STAT3) agonist. Originally discovered by researchers at the University of Southern California (USC) and developed in collaboration with Carthronix (now Innata Bio), 423F acts by binding to domain 2 of gp130 to promote receptor homodimerization. This homodimerization selectively activates downstream STAT3 and MYC signaling pathways while preventing IL-6 and Oncostatin M-induced heterodimerization with IL-6R and OSMR, thereby suppressing hyperinflammation. Preclinical studies have demonstrated that 423F promotes cartilage regeneration, mitigates osteoarthritis, and enhances skeletal muscle regeneration in models of Duchenne muscular dystrophy (DMD) and rotator cuff tears by regulating fibro-adipogenic progenitors (FAPs) and satellite cells.