Objective To review the regulation of microRNA-17-92 cluster on bone development, remodeling, and metabolism. Methods The related literature was reviewed. The clinical genetic phenotype, animal experiment, and cell research were illustrated so as to explore the possible regulatory mechanisms. Results MicroRNA-17-92 cluster is involved in physiological normal organs development, pathological neoplasm occurrence, and development. Recently, studies have shown that microRNA-17-92 cluster constitutes an intricate molecular signaling network with its upstream transcription factors and downstream targeting proteins, which controls bone development, remodeling, and metabolism exquisitely. Conclusion Present fundamental researches have certain understanding of the regulatory mechanisms of microRNA-17-92 cluster on bone development, remodeling, and metabolism. However, the exact mechanisms under these processes remain unknown.
Objective To summary the functional roles and molecular mechanisms of microRNA (miRNA) in osteoblast differentiation so as to supply information for basic and cl inical researches. Methods Recent l iterature concerning miRNA in osteoblast differentiation was reviewed. The information was classified and summarized. Results miRNAs critically regulate bone morphogenetic protein, transforming growth factor β, and Wnt/β-catenin signal ing pathways during osteoblast differentiation. In pathological conditions, especially in some disorders of abnormal osteoblast differentiation, downregulated miRNA expression has been observed. Conclusion miRNA may represent a novel biomarker for diagnosis, and a candidate target therapies for the disorders with abnormal osteoblast differentiation.
ObjectivesTo systematically review the value of cross-linked carboxy-terminal telopeptide of type I collagen (ICTP) in the diagnosis of bone metastases of lung cancer.MethodsThe Cochrane Library, PubMed, EMbase, WanFang Data and CBM databases were electronically searched to collect studies on ICTP in the diagnosis of lung cancer bone metastases from inception to November 2017. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies by QUADAS-2 standard. Meta-analysis was performed by using Meta-Disc 1.4 software.ResultsA total of 8 studies involving 781 patients were included. The results of meta-analysis showed that the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnosis odds ratio and area under the curve of summary receiver operating characteristics were 71% (95%CI 0.65 to 0.76), 80% (95%CI 0.76 to 0.84), 3.79 (95%CI 2.31 to 6.21), 0.35 (95%CI 0.25 to 0.49), 14.67 (95%CI 6.99 to 30.81) and 0.860 3, respectively.ConclusionsICTP cooperate with imaging tests may be accurate and practical in diagnosis of bone metastases of lung cancer. Due to the limited quality and quantity of included studies, the above results should be validated by more studies.
ObjectiveTo review the pathological effects of cellular senescence in the occurrence and development of osteoarthritis (OA) and potential therapeutic targets.MethodsThe role of chondrocyte senescence, synovial cell senescence, mesenchymal stem cells senescence in OA, and the biological mechanism and progress of chondrocyte senescence were summarized by consulting relevant domestic and abroad literature.ResultsThe existing evidence has basically made clear that chondrocyte senescence, mesenchymal stem cells senescence, and cartilage repair abnormalities, and the occurrence and development of OA have a certain causal relationship, and the role of the senescence of synovial cells, especially synovial macrophages in OA is still unclear. Transcription factors and epigenetics are the main mechanisms that regulate the upstream pathways of cellular senescence. Signal communication between cells can promote the appearance of senescent phenotypes in healthy cells. Targeted elimination of senescent cells and promotion of mesenchymal stem cells rejuvenation can effectively delay the progress of OA.ConclusionCellular senescence is an important biological phenomenon and potential therapeutic target in the occurrence and development of OA. In-depth study of its biological mechanism is helpful to the early prevention and treatment of OA.
Objective To Investigate the effects of lithocholic acid (LCA) on the balance between osteogenic and adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Methods Twelve 10-week-old SPF C57BL/6J female mice were randomly divided into an experimental group (undergoing bilateral ovariectomy) and a control group (only removing the same volume of adipose tissue around the ovaries), with 6 mice in each group. The body mass was measured every week after operation. After 4 weeks post-surgery, the weight of mouse uterus was measured, femur specimens of the mice were taken for micro-CT scanning and three-dimensional reconstruction to analyze changes in bone mass. Tibia specimens were taken for HE staining to calculate the number and area of bone marrow adipocytes in the marrow cavity area. ELISA was used to detect the expression of bone turnover markers in the serum. Liver samples were subjected to real-time fluorescence quantitative PCR (RT-qPCR) to detect the expression of key genes related to bile acid metabolism, including cyp7a1, cyp7b1, cyp8b1, and cyp27a1. BMSCs were isolated by centrifugation from 2 C57BL/6J female mice (10-week-old). The third-generation cells were exposed to 0, 1, 10, and 100 μmol/L LCA, following which cell viability was evaluated using the cell counting kit 8 assay. Subsequently, alkaline phosphatase (ALP) staining and oil red O staining were conducted after 7 days of osteogenic and adipogenic induction. RT-qPCR was employed to analyze the expressions of osteogenic-related genes, namely ALP, Runt-related transcription factor 2 (Runx2), and osteocalcin (OCN), as well as adipogenic-related genes including Adiponectin (Adipoq), fatty acid binding protein 4 (FABP4), and peroxisome proliferator-activated receptor γ (PPARγ). Results Compared with the control group, the body mass of the mice in the experimental group increased, the uterus atrophied, the bone mass decreased, the bone marrow fat expanded, and the bone metabolism showed a high bone turnover state. RT-qPCR showed that the expressions of cyp7a1, cyp8b1, and cyp27a1, which were related to the key enzymes of bile acid metabolism in the liver, decreased significantly (P<0.05), while the expression of cyp7b1 had no significant difference (P>0.05). Intervention with LCA at concentrations of 1, 10, and 100 μmol/L did not demonstrate any apparent toxic effects on BMSCs. Furthermore, LCA inhibited the expressions of osteogenic-related genes (ALP, Runx2, and OCN) in a dose-dependent manner, resulting in a reduction in ALP staining positive area. Concurrently, LCA promoted the expressions of adipogenic-related genes (Adipoq, FABP4, and PPARγ), and an increase in oil red O staining positive area. Conclusion After menopause, the metabolism of bile acids is altered, and secondary bile acid LCA interferes with the balance of osteogenic and adipogenic differentiation of BMSCs, thereby affecting bone remodelling.