Differential circRNA and mRNA Expression Profiling During Osteogenic Differentiation in Rat Bone Marrow Mesenchymal Stem Cells.

BACKGROUND Circular RNAs (circRNAs) play important roles in gene expression and signaling pathways. The study aimed to identify the differential expression of circRNAs and mRNAs in the osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs) and to explore the biological function of circRNAs in the osteogenic differentiation of rBMSCs. MATERIAL AND METHODS High-throughput sequencing was used to detect differentially expressed circular RNA and mRNA during osteogenic differentiation of rBMSCs. The RNAs were analyzed for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment to predict their potential role in regulating rBMSC osteogenesis. MiRanda, Circatlas, and miRDB databases were used to predict target relationships between circRNA, miRNA, and mRNA.The regulatory network was constructed by Cytoscape (version 3.6.1). The RNA-Seq findings were validated by quantitative real-time PCR (qRT-PCR). RESULTS The results revealed that 29 differentially expressed circRNAs and 2453 differentially expressed mRNAs were detected during the osteogenic differentiation of rBMSCs. Many differentially expressed circRNAs were closely related to osteogenic differentiation of cells. Among them, circRNAs_1809 and Kitlg were the significantly increased circRNA and mRNA during osteogenic differentiation of rBMSCs. The ceRNA network showed that circRNA_1809 could target the Kitlg gene through miR-370-3p. CONCLUSIONS CircRNAs may play an important role in the osteogenic differentiation of rBMSCs. CircRNA_1809 may acts as a sponge for miR-370-3p and regulate the osteogenic differentiation of rBMSCs by targeting Kitlg; however, this hypothesis needs further verification. This study laid a theoretical foundation for further understanding the mechanism of circRNAs regulating osteogenic differentiation of rBMSCs.

[Distribution of WNT10A gene rs10177996 polymorphism between Han and Uygur populations in Xinjiang area].

PURPOSE: To explore the characteristics of distribution of WNT10A gene rs10177996 polymorphism between Han and Uygur populations in Xinjiang area. METHODS: A cross-sectional survey on 154 Han individuals in Urumqi area and 134 Uygur individuals in Kashgar area was performed. Buccal epithelial cells were harvested using Cotton swab scraping, and DNA was extracted by special kit. After screening, the corresponding SNP segments of qualified samples were propagated by PCR. Dideoxy-mediated chain termination method was used for gene sequencing, and then, genotyping was conducted with corresponding software. Statistical analysis of genetic data was performed by SPSS 23.0 software package. RESULTS: Among Uygur nationality in Kashgar area, the frequencies of CC, CT, TT genetypes in rs10177996 were 8.21%, 30.60% and 61.19%, respectively. The allele frequency of C was 23.51% and T was 76.49%. Among Han nationality in Urumqi area, the frequencies on CC, CT, TT genetypes of rs10177996 were 9.74%, 43.51% and 46.75%, respectively. The allele frequency of C was 31.49% and T was 68.51%. When compared with Han nationality, the frequency of TT was significantly higher in Uygur nationality(P=0.046). When compared with European, the frequency of TT was significantly lower in Uygur nationality (P=0.05). When compared with European, the frequency of TT was significantly lower in Han nationality(P＜0.01). Compared with European, the distribution on C allele frequency was significantly higher, the distribution on T allele frequency was significantly lower in Han nationality (P=0.033). However, there was no significant difference between Han nationality in Urumqi area and Uygur nationality in Kashgar area (P＞0.05), and, between Uygur nationality in Kashgar area and European (P＞0.05). Meanwhile, there was no significant difference in gender between Uygur nationality in Kashgar area and Han nationality in Urumqi area (P＞0.05). CONCLUSIONS: The distributions of WNT10A gene rs10177996 SNP among Han nationality in Urumqi area, Uygur nationality in Kashgar area and the reported European population are obviously different.

Risk factors for dislocation after revision total hip arthroplasty: A systematic review and meta-analysis.

BACKGROUND: No formal systematic review or meta-analysis was performed up to now to summarize the risk factors of dislocation after revision total hip arthroplasty(THA). AIMS: The present study aimed to quantitatively and comprehensively conclude the risk factors of dislocation after revision total hip arthroplasty. METHODS: A search was applied to CNKI, Embase, Medline, and Cochrane central database (all up to October 2016). All studies assessing the risk factors of dislocation after revision THA without language restriction were reviewed, and qualities of included studies were assessed using the Newcastle-Ottawa Scale. Data were pooled and a meta-analysis completed. RESULTS: A total of 8 studies were selected, which altogether included 4656 revision THAs. 421 of them were cases of dislocation occurred after surgery, suggesting the accumulated incidence of 9.04%. Results of meta-analyses showed that age at surgery (standardized mean difference -0.222; 95% CI -0.413-0.031), small-diameter femoral heads (≤28 mm) (OR 1.451; 95%CI 1.056-1.994), history of instability (OR 2.739; 95%CI 1.888-3.974), number of prior revisions ≥ 3 (OR, 2.226; 95% CI, 1.569-3.16) and number of prior revisions ≥ 2 (OR 1.949; 95% CI 1.349-2.817), acetabular components with elevated rim liner were less likely to develop dislocation after revision THA (OR 0.611; 95% CI 0.415-0.898). CONCLUSIONS: Related prophylaxis strategies should be implemented in patients involved with above-mentioned risk factors to prevent dislocation after revision THA.

MicroRNA-126 Overexpression Inhibits Proliferation and Invasion in Osteosarcoma Cells.

This study investigated the biological effects of microRNA-126 overexpression in human MG63 osteosarcoma cells. A recombinant plasmid expressing microRNA-126, pcDNA6.2-microRNA-126, was constructed and transfected into MG63 cells. Using real-time fluorogenic quantitative polymerase chain reaction, the microRNA-126 expression was measured in microRNA-126-MG63 group, Ctrl-MG63 group, and blank group. Cell proliferation, cell cycle distribution, cell migration, and invasion were analyzed using methyl thiazolyl tetrazolium assay, flow cytometer, wound-healing assay, and transwell assay, respectively. As expected, microRNA-126 expression was higher in microRNA-126-MG63 group than in Ctrl-MG63 group and blank group (both P < .05). After 48/72 hours of transfection, cell proliferation in microRNA-126-MG63 group was significantly reduced compared to blank group (both P < .05). Compared to blank group, cell population in G0/G1 stage was significantly higher in microRNA-126-MG63 group, accompanied by lower cell numbers in the S and G2/M phases and decreased proliferation index (all P < .05). Wound-healing assay showed a wider scratch width in microRNA-126-MG63 group and reduced cell migration than blank group (both P < .05). Cells overexpressing microRNA-126 exhibited reduced ADAM9 expression levels compared to other 2 groups (all P < .05), suggesting ADAM9 is a target of microRNA-126. Cell proliferation, migration, and invasion rates were reduced in microRNA-126 group after 48/72 hours of transfection, compared with blank group (all P < .05). Cotransfection of pcDNA6.2-microRNA-126 and pMIR-ADAM9 into MG63 cells led to higher cell proliferation, invasion, and migration rates, compared with transfection of pcDNA6.2-microRNA-126 alone (all P < .05). In summary, our data show that microRNA-126 inhibits cell proliferation, migration, and invasion in human osteosarcoma cells by targeting ADAM9.

Serum levels of 25-hydroxyvitamin D and functional outcome among postmenopausal women with hip fracture.

OBJECTIVE: The main objective of the current study was to assess the distribution and its prognostic value of serum 25-hydroxyvitamin D (25[OH] D) levels assessed at admission in Chinese postmenopausal women with hip fracture. METHODS: From January 1, 2012 to December 31, 2013, all postmenopausal women with first-ever hip fracture were recruited to participate in the study. Serum 25[OH] D levels were measured at admission. The functional evaluation at the time of discharge was performed by the Barthel Index (BI). The prognostic value of 25[OH] D to predict the functional outcome within discharge was analyzed by logistic regression analysis, after adjusting for the possible confounders. RESULTS: In our study, 261 patients were included and assessed. In the 76 patients with an unfavorable functional outcome, serum 25(OH) D levels were lower compared with those in patients with a favorable outcome [11.8(IQR, 9.9-16.1) ng/ml; 16.8(IQR, 13.6-21.4) ng/ml, respectively; P<0.0001]. In multivariate analysis, there was an increased risk of unfavorable outcome associated with serum 25(OH) D levels ≤ 20 ng/ml (OR 5.24, 95%CI: 3.11-8.15; P<0.0001) after adjusting for possible confounders. CONCLUSIONS: Our data support an association between serum 25[OH] D levels and prognosis in Chinese postmenopausal women with hip fracture.

Apoptosis prediction via inhibition of AKT signaling pathway by neogrifolin.

Neogrifolin, a natural biologically active substance isolated from the edible bodies of the mushroom Albatrellus confluens, has been shown to possess several pharmacological properties. No studies were investigated against osteosarcoma cancer. Hence, in this study, we investigated the apoptosis-inducing effects and the mechanisms of neogrifolin on human osteosarcoma cells. Our results demonstrated that neogrifolin induced concentration- and time-dependent suppression of proliferation. Further, induction of apoptosis in U2OS and MG63 osteosarcoma cell lines were also observed. Neogrifolin induced the release of cytochrome c accompanied by activation of caspase-9, caspase-3 and cleavage of poly (ADP-ribose) polymerase (PARP). In addition, z-VAD-fmk, a universal inhibitor of caspases, prevented caspase-3 activation and PARP cleavage and inhibited neogrifolin-induced cell growth inhibition. Furthermore, neogrifolin treatment resulted in a reduction of phosphorylated AKT level, FOXO transcription factor, and glycogen synthase kinase 3 (GSK3). Knockdown of GSK3 with siRNA inhibited the apoptotic effects of neogrifolin. On the other hand, neogrifolin treatment also down-regulated the expression of the inhibitor of apoptosis protein (IAP) in both osteosarcoma cells. Collectively, our results suggested that neogrifolin is a potential candidate for osteosarcoma.

Transglutaminase-2 is Involved in Cell Apoptosis of Osteosarcoma Cell Line U2OS Under Hypoxia Condition.

Osteosarcoma is the most common type of solid bone cancer, which is the second leading cause of cancer-related death. Hypoxia is an ordinary phenomenon in solid tumor tissues and can induce cell apoptosis but the specific molecular mechanism remains unclear. In this study, we explored the effect and the molecular mechanism of Transglutaminase 2 (TG2) on cell apoptosis in osteosarcoma U2OS cells under hypoxia. We found the enzymatic activity of TG2 is significantly increased and the expression of TG2 is remarkably up-regulated under hypoxia condition. Cell apoptotic rate is markedly increased upon knockdown of TG2 by siRNA under hypoxia. We further investigated the mechanism of cell apoptosis and found Bax protein is significantly increased after depletion of TG2 under hypoxia. Moreover, our data also show that cytochrome C (Cyt C) is significantly increased in cytoplasm and markedly decreased in mitochondria of U2OS cells after depletion of TG2 under hypoxia. Our results suggest that TG2 can inhibit tumor cell apoptosis through down-regulation of Bax and prevention of release Cyt C from mitochondria into cytoplasm.