Diabetic osteoporosis (DOP) is attributed to the aberrant physiological function of bone marrow mesenchymal stem cells (BMSCs) under high glucose (HG) environment. MicroRNAs (miRNAs) are involved in the pathological processes of DOP. We aimed to explore the underlying mechanism of miRNA in DOP. BMSCs were cultured in osteogenic medium with HG to induce osteogenic differentiation, and the interaction between miR-493-5p and ZEB2 was assessed by luciferase assay. Herein, we found miR-493-5p is gradually reduced during osteogenic differentiation in BMSCs. HG treatment inhibits osteogenic differentiation and induces an up-regulation of miR-493-5p leading to reduced level of its downstream target ZEB2. Inhibition of miR-493-5p attenuates HG-induced osteogenic differentiation defects by upregulation of ZEB2. Mechanistically, miR-493-5p/ZEB2 signalling mediates HG-inhibited osteogenic differentiation by inactivation of Wnt/β-catenin signalling. More importantly, knockdown of miR-493-5p therapeutically alleviated the DOP condition in mice. HG prevents BMSCs osteogenic differentiation via up-regulation of miR-493-5p, which results in reduced level of ZEB2 by directly targeting its 3′-untranslated region of mRNA. Thus, miR-493-5p/ZEB2 is a potential therapeutic target and provides novel strategy for the treatment and management of DOP.

Objectives Osteoarthritis (OA) is a joint degenerative disease that commonly occurs in older people and affect the quality of life. Triptolide (TPL), a compound derived from Tripterygium wilfordii, has been shown to exhibit anti-inflammatory properties. Here, we investigated the therapeutic effect of TPL on the experimental OA as well as the underlying molecular mechanisms. Methods OA models were established using monosodium iodoacetate (MIA) or surgery. The arthritis score and paw withdrawal threshold value of knees were used to evaluate the degree of arthritis. The level and expression of proinflammatory cytokines were evaluated by quantitative real-time PCR and ELISA kits. Key findings In surgery and MIA-induced OA rats, TPL alleviated arthritis symptoms and reduced inflammatory cytokine production in serum. In primary chondrocytes, TPL dose-dependently reversed lipopolysaccharide (LPS)-induced cell proliferation. Moreover, LPS-induced cell apoptosis and the expressions of proinflammatory cytokines interleukin-(IL-)6, IL-8, IL-1β, IL-12, tumour necrosis factor-α (TNF-α) and interferon-gamma (INF-γ) were also attenuated by TPL. Mechanistically, the therapeutic effects of TPL on OA were effective by dampening nuclear factor kappa B (NF-κB) activity leading to reduced proinflammatory cytokines production and inflammatory response. Conclusions TPL acts as an effective therapeutic drug for OA by mediating NF-κB signalling, thereby leading to the reduced proinflammatory cytokines production and inflammatory response.