Original Full Length ArticlePeroxisomal dysfunction is associated with up-regulation of apoptotic cell death via miR-223 induction in knee osteoarthritis patients with type 2 diabetes mellitus

- Peroxisomal gene array showed down-regulation of PEX-16 in OA/DM chondrocytes.
- Down-regulation of PEX-16 induces miR-223 induction.
- Down-regulation of miR-223 inhibits apoptosis.
- Over-expression of miR-223 results in severe cartilage destruction in db/db mice.
- Our study suggests that peroxisomal dysfunction in DM could be responsible for early incidence of OA.

Recent increasing evidences showing the interconnection between mitochondria and peroxisome in performing metabolic functions imply that peroxisome dysfunction could lead to a wide variety of human diseases including cancer and osteoarthritis (OA) as mitochondria dysfunction. Even though there is a higher incidence and development of OA in diabetes mellitus (DM) patients, there is not much evidential mechanism study in this inter-regulation between OA and OA with DM in a new view of peroxisome. In this study, we analyzed the alteration of peroxisomal gene expression that could responsible for pathological difference between OA chondrocytes and OA/DM chondrocytes. To discriminate responsible genes in the OA/DM pathogenesis, the expressions of three hundred sixty-two genes reported to differentially relate to peroxisome were analyzed with OA chondrocytes in OA cartilage and OA/DM chondrocytes in the cartilage of OA with DM patient. Among them, PEX-16, a component of peroxisome, was significantly down-regulated in OA/DM chondrocytes and this down-regulation of PEX-16 increased the miR-223 induction. Knockdown studies using PEX-16 null cell line and PEX-16 specific siRNA showed the significant increase in apoptotic cell death. Moreover, over-expression of miR-223 stimulates apoptotic cell death in human articular chondrocytes and induced severe cartilage destruction in db/db mice. In conclusion, our study showed the differential peroxisomal gene expression profiles for OA/DM chondrocytes from OA chondrocytes and suggests the possibility that peroxisomal dysfunction in OA/DM could be responsible for early incidence and development of OA in DM patients.