State of the Art: The Immunomodulatory Role of MSCs for Osteoarthritis

Abstract

Osteoarthritis (OA) has generally been introduced as a degenerative disease; however, it has recently been understood as a low‐grade chronic inflammatory process that could promote symptoms and accelerate the progression of OA. Current treatment strategies, including corticoster-oid injections, have no impact on the OA disease progression. Mesenchymal stem cells (MSCs) based therapy seem to be in the spotlight as a disease‐modifying treatment because this strategy provides enlarged anti‐inflammatory and chondroprotective effects. Currently, bone marrow, adipose de-rived, synovium‐derived, and Wharton’s jelly‐derived MSCs are the most widely used types of MSCs in the cartilage engineering. MSCs exert immunomodulatory, immunosuppressive, antiapop-totic, and chondrogenic effects mainly by paracrine effect. Because MSCs disappear from the tissue quickly after administration, recently, MSCs‐derived exosomes received the focus for the next‐gen-eration treatment strategy for OA. MSCs‐derived exosomes contain a variety of miRNAs. Exosomal miRNAs have a critical role in cartilage regeneration by immunomodulatory function such as promoting chondrocyte proliferation, matrix secretion, and subsiding inflammation. In the future, a personalized exosome can be packaged with ideal miRNA and proteins for chondrogenesis by en-riching techniques. In addition, the target specific exosomes could be a gamechanger for OA. How-ever, we should consider the off‐target side effects due to multiple gene targets of miRNA.