Osteoarthritis (OA) and rheumatoid arthritis (RA) are both debilitating diseases that cause significant morbidity in the US population. Extracellular vesicles (EVs), including exosomes and microvesicles, are now recognized to play important roles in cell-to-cell communication by transporting various proteins, microRNAs (miRNAs), and mRNAs. A recent study presents current knowledge on the role of EVs in both RA and OA, and their potential role as therapeutic targets for modulation of these debilitating diseases. Key highlights include:

• EV-derived proteins and miRNAs impact cell viability and cell differentiation, and are likely to play a prominent role in the pathophysiology of both OA and RA.
• RA models have shown that EVs stimulated with inflammatory cytokines are capable of inducing apoptosis resistance in T cells, presenting antigen to T cells, and causing extracellular damage with matrix-degrading enzymes.
• EVs derived from rheumatoid models have also been shown to induce secretion of COX-2 and stimulate angiogenesis.