CD31 orchestrates metabolic regulation in autophagy pathways of rheumatoid arthritis.

Synovitis is characterized by a distinctmetabolic profile featuring the accumulation of lactate, a byproduct of cellular metabolism within inflamed joints. This study reveals that the activation of the CD31 signal by lactate instigates a metabolic shift, specifically initiating endothelial cell autophagy. This adaptive process plays a pivotal role in fulfilling the augmented energy and biomolecule demands associated with the formation of new blood vessels in the synovium of Rheumatoid Arthritis (RA). Additionally, the amino acid substitutions in the CD31 cytoplasmic tail at the Y663F and Y686F sites of the immunoreceptor tyrosine-based inhibitory motifs (ITIM) alleviate RA. Mechanistically, this results in the downregulation of glycolysis and autophagy pathways. These findings significantly advance our understanding of potential therapeutic strategies for modulating these processes in synovitis and, potentially, other autoimmune diseases.