The emerging role of Interleukin 37 in bone homeostasis and inflammatory bone diseases

•Interleukin 37 (IL-37) is a new member of the IL-1 family, which broadly reduces innate inflammation as well as acquired immune responses.•IL-37 plays an anti-inflammatory role as a dual cytokine with both intra- and extra-cellular functions.•IL-37 can inhibit osteoclast differentiation directly and indirectly and promote osteogenic differentiation of bone marrow mesenchymal stem cells.•The levels of IL-37 were abnormal in patients with inflammatory bone diseases.•In vivo studies have confirmed that recombinant IL-37 treatment displayed therapeutic potential in inflammatory bone diseases. Interleukin 37 (IL-37) is a newly identified cytokine that belongs to the IL-1 family. Unlike other members of the IL-1 family, it has been demonstrated that IL-37 possesses anti-inflammatory characteristics in both innate and acquired immune responses. Recently, significant progress has been made in understanding the role of IL-37 in inflammatory signaling pathways. Meanwhile, IL-37 has also attracted more and more attention in bone homeostasis and inflammatory bone diseases. The latest studies have revealed that IL-37 palys an essential role in the regulation of osteoclastogenesis and osteoblastogenesis. The levels of IL-37 are abnormal in patients with inflammatory bone diseases such as rheumatoid arthritis (RA), osteoarthritis (OA), ankylosing spondylitis (AS), and periodontitis. In addition, in vivo studies have further confirmed that recombinant IL-37 treatment displayed therapeutic potential in these diseases. The present review article aims to provide an overview describing the biological functions of IL-37 in bone homeostasis and inflammatory bone diseases, thus shedding new light on a novel therapeutic strategy in the future.