Mesenchymal stem/stromal cells(MSCs):origin,immune regulation,and clinical applications

The associations between inflammation and tissue regeneration are highly conserved during the evolution of multicellular organisms[1].Appropriate activation of immune cells is vital for the repair of damaged tissues and the maintenance of tissue homeostasis[2].Mesenchymal stem/stromal cells(MSCs)are of the most responsive cell populations to inflammation in tissues.MSCs are a kind of tissue stem cells that were initially identified in the bone marrow stroma in the late 1960s by Friedenstein[3]and further characterized and renamed by Arnold Caplan[4].MSCs possess stemness,as defined by their ability to differentiate into osteoblasts,adipocytes,and chondrocytes[5].These cells are present in almost all tissues and are highly mobile in response to tissue damage signals[6].In this special issue,experts took different perspectives and analyzed MSCs based on immune regulation,pathogenesis,infection,mechanisms of action,and clinical applications.It is anticipated that this special issue will provide valuable information to improve understanding of the critical pathophysiological roles and appropriate clinical applications of this unique cell population.