Characterization of immune microenvironment infiltration and m6A regulator-mediated RNA methylation modification patterns in osteoarthritis.

Background: Few studies have been reported the potential role of N6-methyladenosine (m6A) modification in osteoarthritis (OA). We investigated the patterns of m6A modification in the immune microenvironment of OA. Methods: We evaluated the m6A modification patterns based on 22 m6A regulators in 139 OA samples and systematically associated these modification patterns with immune cell infiltration characteristics. The function of m6A phenotype-related differentially expressed genes (DEGs) was investigated using gene enrichment analysis. An m6A score model was constructed using principal component analysis (PCA), and an OA prediction model was established based on the key m6A regulators. We used real-time PCR analysis to detect the changes of gene expression in the cell model of OA. Results: Healthy and OA samples showed significant differences in the expression of m6A regulators. Nine key m6A regulators, two m6A modification patterns, m6A-related genes and two gene clusters were identified. Some m6A regulators had a strong correlation with each other. Gene clusters and m6A clusters have high similarity, and cluster A corresponds to a high m6A score. Immunocytes infiltration differed significantly between the two clusters, with the m6A cluster B and gene cluster B having more types of infiltrating immunocytes than cluster A. The predictive model can also predict the progression of OA through m6A regulators expression. The results of real-time PCR analysis showed that the gene expression in the cell model of OA is similar to that of the m6A cluster B. Conclusions: Our study reveals for the first time the potential regulatory mechanism of m6A modification in the immune microenvironment of OA. This study also sheds new light on the pathogenesis of OA.

The effects of teriparatide and bisphosphonates on new fractures in postmenopausal women with osteoporosis: A protocol for systematic review and meta-analysis.

BACKGROUND: To systematically evaluate the efficacy of teriparatide and bisphosphonates in preventing fractures in postmenopausal women with osteoporosis. MATERIALS AND METHODS: We performed a systematic search of PubMed, Embase, and the Cochrane Library for randomized controlled trials (RCTs) that compared teriparatide and bisphosphonates for osteoporosis treatment. Searches were performed without language restrictions and included studies from beginning of time to March 2019. Two authors independently screened and extracted the selected article. The quality of the included studies was evaluated using the Cochrane system evaluation method. Data were extracted and analysed using RevMan 5.2 software. RESULTS: Nine RCTs were included for a total of 2990 postmenopausal women with osteoporosis. Of these, 1515 patients were treated with teriparatide and 1475 were treated with bisphosphonates. After pooling the data of 9 studies, there were significant differences between teriparatide and bisphosphonates [relative risk (RR): 0.61, 95% confidence interval (CI) (0.51, 0.74)] in the prevention of fractures according to different follow-up durations (P < .05), whatever alendronate [RR: 0.51, 95% CI (0.27, 0.95)] and other bisphosphonates [RR: 0.63, 95% CI (0.51, 0.77)]. In addition, we found significant differences between teriparatide and bisphosphonates in the prevention of vertebral fractures [RR: 0.47, 95% CI (0.35, 0.64)] and non-vertebral fractures [RR: 0.76, 95% CI (0.58,0.99)]. There were no significant differences in adverse effects between teriparatide and bisphosphonates [RR: 0.89, 95% CI (0.76, 1.03)]. CONCLUSIONS: Based on the results of our meta-analysis, teriparatide was better than bisphosphonates in preventing fractures in postmenopausal women with osteoporosis both in the short-term and long-term follow-up periods. Teriparatide was superior to bisphosphonates in preventing vertebral and non-vertebral fractures. These drugs did not differ in terms of their adverse effects. More high-quality studies are needed to compare other factors such as costs and adverse reactions.

Silencing of miR-483-5p alleviates postmenopausal osteoporosis by targeting SATB2 and PI3K/AKT pathway.

Postmenopausal osteoporosis (PMOP) poses a significant threat to women's health worldwide. However, detailed molecular mechanism and therapeutic strategy for PMOP remain insufficient. Accumulating evidence suggests that miR-48-5p is implicated in the pathogenesis of osteoporosis. The present study aimed to determine the role and mechanism of miR-483-5p in PMOP. Results from PMOP patients demonstrated that miR-483-5p was up-regulated and SATB2 was down-regulated. Luciferase reporter assay identified SATB2 as a direct target gene of miR-483-5p. Experiments in MC3T3-E1 cells indicated that miR-483-5p mimic markedly inhibited cell viability as well as the expressions of OPG, RUNX2 and BMP2. And miR-483-5p inhibitor, SATB2-overexpressed lentiviruses (Lv-SATB2) or LY294002 (PI3K/AKT inhibitor) significantly reversed the above results. Similarly, PI3K/AKT signaling was activated by miR-483-5p mimic, and was inhibited in miR-483-5p inhibitor, Lv-SATB2 or LY294002 treated cells. In vivo experiments showed that miR-483-5p inhibitor significantly increased the bone mineral density and biomechanical parameters of femurs in ovariectomized (OVX) rats by targeting SATB2. In addition, the osteogenic differentiation and PI3K/AKT signaling were also regulated by miR-483-5p-SATB2 axis. Taken together, our findings indicated that miR-483-5p contributed to the pathogenesis of PMOP by inhibiting SATB2 and activating PI3K/AKT pathway. MiR-483-5p/SATB2 could be selected as a potential therapeutic target for PMOP.