LncRNA HOTTIP impacts the proliferation and differentiation of fibroblast-like synoviocytes in ankylosing spondylitis through the microRNA-30b-3p/PGK1 axis.

OBJECTIVE: Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been reported to exert regulatory effects on biological processes. This study intended to assess the role of the lncRNA HOXA transcript at the distal tip (HOTTIP)/miR-30b-3p/phosphoglycerate kinase 1 (PGK1) axis in ankylosing spondylitis (AS). METHODS: Levels of HOTTIP, miR-30b-3p and PGK1 in AS synovial tissues and cultured AS fibroblast-like synoviocytes (ASFLSs) were assessed. The ASFLSs were identified and, respectively, treated with altered expression of HOTTIP and miR-30b-3p, and then, the proliferation and differentiation of the ASFLSs were assessed. The AS mouse models were established by injection of proteoglycan and Freund's complete adjuvant and then were treated with altered expression of HOTTIP and miR-30b-3p, and the pathological changes and apoptosis of synoviocytes in mice' synovial tissues were measured. The relationship of HOTTIP, miR-30b-3p and PGK1 was verified. RESULTS: HOTTIP and PGK1 were elevated, while miR-30b-3p was reduced in AS synovial tissues and ASFLSs. Elevated miR-30b-3p or inhibited HOTTIP restrained proliferation and differentiation of ASFLSs and also improved the pathological changes and promoted apoptosis of synoviocytes in mice's synovial tissues. PGK1 was a target of miR-30b-3p, and miR-30b-3p could directly bind to HOTTIP. Silencing miR-30b-3p or overexpressing PGK1 reversed the improvement of AS by knocking down HOTTIP or up-regulating miR-30b-3p. CONCLUSION: Our study suggests that reduced HOTTIP ameliorates AS progression by suppressing the proliferation and differentiation of ASFLSs through the interaction of miR-30b-3p and PGK1.

Genome-wide analysis of aberrant methylation of enhancer DNA in human osteoarthritis.

BACKGROUND: Osteoarthritis is a chronic musculoskeletal disease characterized by age-related gradual thinning and a high risk in females. Recent studies have shown that DNA methylation plays important roles in osteoarthritis. However, the genome-wide pattern of methylation in enhancers in osteoarthritis remains unclear. METHODS: To explore the function of enhancers in osteoarthritis, we quantified CpG methylation in human enhancers based on a public dataset that included methylation profiles of 470,870 CpG probes in 108 samples from patients with hip and knee osteoarthritis and hip tissues from healthy individuals. Combining various bioinformatics analysis tools, we systematically analyzed aberrant DNA methylation of the enhancers throughout the genome in knee osteoarthritis and hip osteoarthritis. RESULTS: We identified 16,816 differentially methylated CpGs, and nearly half (8111) of them were from enhancers, suggesting major DNA methylation changes in both types of osteoarthritis in the enhancer regions. A detailed analysis of hip osteoarthritis identified 2426 differentially methylated CpGs in enhancers between male and female patients, and 84.5% of them were hypomethylated in female patients and enriched in phenotypes related to hip osteoarthritis in females. Next, we explored the enhancer methylation dynamics among patients with knee osteoarthritis and identified 280 differentially methylated enhancer CpGs that were enriched in the human phenotypes and disease ontologies related to osteoarthritis. Finally, a comparison of enhancer methylation between knee osteoarthritis and hip osteoarthritis revealed organ source-dependent differences in enhancer methylation. CONCLUSION: Our findings indicate that aberrant methylation of enhancers is related to osteoarthritis phenotypes, and a comprehensive atlas of enhancer methylation is useful for further analysis of the epigenetic regulation of osteoarthritis and the development of clinical drugs for treatment of osteoarthritis.

Activation of GPR30 promotes osteogenic differentiation of MC3T3-E1 cells: An implication in osteoporosis.

Osteoporosis is an age-related disease characterized by reduced bone volume and disturbed bone metabolism. Novel therapies to rescue or prevent reduced bone mass by guiding the differentiation of pluripotent bone marrow stromal cells away from adipocyte differentiation and toward osteoblastic differentiation may serve as a valuable treatment option against osteoporosis. Estrogen has long been recognized as a key effector of bone formation and mineralization, but the exact mechanisms involved remain poorly understood. In the present study, we investigated the role of the estrogen-specific G protein-coupled receptor 30 (GPR30/GPER) using its specific agonist G1 in MC3T3-E1 preosteoblast cells. Our findings demonstrate that expression of GPR30 is upregulated during osteoblast differentiation and that agonism of GPR30 significantly increases some key markers of mineralization including alkaline phosphatase, osteocalcin, osterix, and type I collagen. We also demonstrate that GPR30 agonism upregulates expression of Runx2, which is recognized as an essential transcription factor involved in bone formation. Additionally, through a series of adenosine monophosphate-activated protein kinase (AMPK)-inhibition experiments using compound C, we show that the positive effects of GPR30 on mineralization and differentiation of preosteoblasts are mediated through the AMPK/anti-acetyl-CoA carboxylase (ACC) pathway. Taken together, the findings of the present study demonstrate the potential of GPR30 as a novel target for the treatment and prevention of osteoporosis.

Dulaglutide mitigates inflammatory response in fibroblast-like synoviocytes.

Rheumatoid arthritis is a common autoimmune disease primarily characterized by chronic inflammation, the formation of an invasive pannus, and destruction of the joints. In the present study, we employed real-time PCR and western blot analysis to investigate the role of dulaglutide in human fibroblast-like synoviocytes (FLS). The results of our study show that dulaglutide exerted a powerful protective effect by rescuing mitochondrial membrane potential, inhibiting the production of NOX-4, and abrogating TNF-α-induced downregulation of the antioxidant GSH. Our findings demonstrate that dulaglutide significantly ameliorated the expression of proinflammatory cytokines and chemokines including IL-1ß, IL-6, MCP-1, and HMGB-1. Matrix metalloproteinases mediate cartilage destruction, thereby aiding in pannus formation. Our findings indicate that dulaglutide treatment significantly downregulated the expression of MMP-3 and MMP-13, two crucial degradative enzymes. Importantly, the results of our study demonstrate that the beneficial effects of dulaglutide are mediated through the JNK/NF-κB signaling pathway, which has been suggested as a potential treatment target against RA. Taken together, the results of this study show that dulaglutide may exert significant protective effects against the progression of RA induced by TNF-α.

Identification of serum miR-124 as a biomarker for diagnosis and prognosis in osteosarcoma.

BACKGROUND: It has been demonstrated that microRNAs (miRNAs) play an important role in the carcinogenesis of osteosarcoma. OBJECTIVE: The aim of the present study was to determine the diagnostic and prognostic value of serum miR-124 in osteosarcoma. METHODS: The serum miR-124 expression levels in 114 osteosarcoma patients, 40 periostitis patients and 50 normal controls were detected using real-time quantitative polymerase chain reaction (RT-qPCR). RESULTS: The level of serum miR-124 was remarkably decreased in osteosarcoma patients when compared to periostitis patients and healthy controls (both p< 0.05). The serum miR-124 levels in osteosarcoma patients were significantly elevated after receiving surgical treatment (p< 0.01). Furthermore, the area under the receiver-operating characteristic (ROC) curve (AUC) for serum miR-124 was 0.846, combining with 79.8% sensitivity and 86.00% specificity. A significant correlation was detected between serum miR-124 expression and distant metastasis (p= 0.0256) as well as clinical stage (p= 0.0006). Similarly, serum miR-124 levels in patients with advanced clinical stage or positive distant metastasis were significantly decreased. Moreover, the Kaplan-Meier method with log-rank test showed that osteosarcoma patients with lower serum miR-124 levels had unfavorable 5 year overall survival and disease free survival rates. Finally, multivariate analysis revealed that serum miR-124 was an independent prognostic indicator for osteosarcoma. CONCLUSIONS: These findings suggested that serum miR-124 might be a promising biomarker with diagnostic and prognostic value for osteosarcoma.