Open AccessRole of Interleukin‐10 in Endochondral Bone Formation in Mice: Anabolic Effect via the Bone Morphogenetic Protein/Smad Pathway
Author(s) -
Jung YounKwan,
Kim GunWoo,
Park HyeRi,
Lee EunJu,
Choi JeYong,
Beier Frank,
Han SeungWoo
Publication year - 2013
Publication title -
arthritis & rheumatism
Language(s) - English
Resource type - Journals
eISSN - 1529-0131
pISSN - 0004-3591
DOI - 10.1002/art.38181
Subject(s) - chondrogenesis , endochondral ossification , chondrocyte , chemistry , microbiology and biotechnology , bone morphogenetic protein , smad , mesenchymal stem cell , cartilage , bone morphogenetic protein 2 , alkaline phosphatase , medicine , endocrinology , signal transduction , biology , anatomy , in vitro , biochemistry , gene , enzyme
Objective Interleukin‐10 (IL‐10) is a pleiotropic immunoregulatory cytokine with a chondroprotective effect that is elevated in cartilage and synovium in patients with osteoarthritis. However, the role of IL‐10 during endochondral bone formation and its mechanism of action have not been elucidated. Methods IL‐10 –/– mice and IL‐10–treated tibial organ cultures were used to study loss and gain of IL‐10 functions, respectively, during endochondral bone formation. Primary chondrocytes from the long bones of mouse embryos were cultured with and without IL‐10. To assess the role of IL‐10 in chondrogenic differentiation, we conducted mesenchymal cell micromass cultures. Results The lengths of whole skeletons from IL‐10 –/– mice were similar to those of their wild‐type littermates, although their skull diameters were smaller. The tibial growth plates of IL‐10 –/– mice showed shortening of the proliferating zone. Treatment with IL‐10 significantly increased tibial lengths in organ culture. IL‐10 also induced chondrocyte proliferation and hypertrophic differentiation in primary chondrocytes in vitro. Mechanistically, IL‐10 activated STAT‐3 and the Smad1/5/8 and ERK‐1/2 MAP kinase pathways and induced the expression of bone morphogenetic protein 2 (BMP‐2) and BMP‐6 in primary chondrocytes. Furthermore, the blocking of BMP signaling attenuated the IL‐10–mediated induction of cyclin D1 and RUNX‐2 in primary chondrocytes and suppressed Alcian blue and alkaline phosphatase staining in mesenchymal cell micromass cultures. Conclusion These results indicate that IL‐10 acts as a stimulator of chondrocyte proliferation and chondrogenic or hypertrophic differentiation via activation of the BMP signaling pathway.