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Osteomyelitis is difficult to cure, and the rapidly rising morbidity is a thorny problem accompanied by a large number of joint replacement applications. Staphylococcus aureus is the main pathogen of osteomyelitis. Circular RNAs (circRNAs), as emerging noncoding RNAs, play important roles in multiple physiopathological processes which could provide novel insights into osteomyelitis.

Background: The potential functions of circular RNAs (circRNAs) and micro RNAs (miRNAs) in osteosarcoma (OS) have not been fully elucidated. Especially, the behavior and mechanism of immune responses in OS development and progression have not been fully demonstrated. It was reported that circRNAs and miRNAs can serve as biomarkers for the diagnosis, prognosis, and therapy of many cancers. This study aimed to identify novel key serum biomarkers to diagnose and predict metastasis of OS based on the analysis of immune cell infiltration characteristics.Methods: The differentially-expressed circRNAs (DEcircRNAs), differentially-expressed miRNAs (DEmiRNAs),and differentially-expressed mRNAs (DEmRNAs) of human OS were investigated based on the microarray data downloaded from Gene Expression Omnibus (GEO) datasets. Then, we analyzed immune characteristics pattern of tumor-infiltrating immune cells in OS. On this basis, we identified statistically-significant transcription factors and performed pathway enrichment analysis. Subsequently, we constructed protein-protein interaction (PPI) and competitive endogenous RNA (ceRNA) networks. Moreover, the biological characteristic of targets in ceRNA networks was proposed. Finally, the expression and diagnostic capability of these potential biomarkers from ceRNA network were confirmed by RT-qPCR in patients’ serum.Results: Seven differentially-expressed circRNAs (DEcircRNAs), 166 differentially-expressed miRNAs (DEmiRNAs) and 175 differentially-expressed mRNAs (DEmRNAs) were identified in total. The highest level of infiltration in OS patients were M0 macrophages, M2 macrophages and CD8+ T cells. Further, M0 macrophages and CD8+ T cells were showed the largest negative correlation coefficients. These significant immune characteristics pattern of tumor-infiltrating immune cells were revealed by the principal component analysis in OS. Moreover, we found 185 statistically-significant transcription factors in which the main significant molecules show the potential in immunotherapy of OS. Hsa-circ-0010220, hsa-miR-326, hsa-miR-338-3p, and FAM98A from ceRNA networks associated with immune cell infiltration were confirmed as the potential novel biomarkers for OS diagnosis, of which FAM98A could distinguish and predict metastasis. Most importantly, a novel diagnostic model consisting of the four promising biomarkers (hsa-circ-0010220, hsa-miR-326, hsa-miR-338-3p, and FAM98A) was highlighted with 0.928 AUC value.Conclusions: In summary, the potenial serum biomarkers to diagnose and predict metastasis of OS based on the analysis of immune cell infiltration characteristics were found, and a novel diagnostic model consisting of four promising serum biomarkers was proposed firstly. These results provided a new perspective for the immunotherapy of OS.

Background The role of circular RNAs (circRNAs) and microRNAs (miRNAs) in osteosarcoma (OS) development has not been fully elucidated. Further, the contribution of the immune response to OS progression is not well defined. However, it is known that circRNAs and miRNAs can serve as biomarkers for the diagnosis, prognosis, and therapy of many cancers. Thus, the aim of this study was to identify novel key serum biomarkers for the diagnosis and metastatic prediction of OS by analysis of immune cell infiltration and associated RNA molecules. Methods Human OS differentially expressed circRNAs (DEcircRNAs), differentially expressed miRNAs (DEmiRNAs), and differentially expressed mRNAs (DEmRNAs) were identified by analysis of microarray data downloaded from Gene Expression Omnibus (GEO) datasets. Further, characteristic patterns of OS-infiltrating immune cells were analyzed. On this basis, we identified statistically significant transcription factors. Moreover we performed pathway enrichment analysis, constructed protein–protein interaction networks, and devised competitive endogenous RNA (ceRNA) networks. Biological targets of the ceRNA networks were evaluated and potential OS biomarkers confirmed by RT-qPCR analysis of the patients’ serum. Results Seven differentially expressed circRNAs, 166 differentially expressed miRNAs, and 175 differentially expressed mRNAs were identified. An evaluation of cellular OS infiltration identified the highest level of infiltration by M0 macrophages, M2 macrophages, and CD8+ T cells, with M0 macrophages and CD8+ T cells as the most prominent. Significant patterns of tumor-infiltrating immune cells were identified by principal component analysis. Moreover, 185 statistically significant transcription factors were associated with OS. Further, in association with immune cell infiltration, hsa-circ-0010220, hsa-miR-326, hsa-miR-338-3p, and FAM98A were identified as potential novel biomarkers for OS diagnosis. Of these, FAM98A had the most promise as a diagnostic marker for OS and OS metastasis. Most importantly, a novel diagnostic model consisting of these four biomarkers (hsa-circ-0010220, hsa-miR-326, hsa-miR-338-3p, and FAM98A) was established with a 0.928 AUC value. Conclusions In summary, potential serum biomarkers for OS diagnosis and metastatic prediction were identified based on an analysis of immune cell infiltration. A novel diagnostic model consisting of these four promising serum biomarkers was established. Taken together, the results of this study provide a new perspective by which to understand immunotherapy of OS.

Circular RNAs (circRNAs) play important roles in a variety of pathological functions. However, the potential functions and detailed mechanisms of circRNAs in osteosarcoma (OS) have not been fully elucidated. In this study, the circRNA, micro RNA (miRNA), and messenger RNA (mRNA) expression profile of human OS was investigated based on the raw microarray data GSE140256, GSE65071 and GSE16088 in Gene Expression Omnibus (GEO) datasets, and seven differentially-expressed circRNAs (DEcircRNAs), 166 differentially-expressed miRNAs (DEmiRNAs), and 175 differentially-expressed mRNAs (DEmRNAs) were identified in total. FunRich was employed to analyze the differentially-expressed transcription factors on the basis of identified DEmiRNAs. In addition, the Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to further study biological functions of the DEmRNAs. Interestingly, post-translational protein modification, collagen-containing extracellular matrix, and single-stranded DNA binding were the most significant pathways enriched for DEmRNAs in GO annotation analysis. Meanwhile, in KEGG pathway enrichment analysis, complement and coagulation cascades, RNA transport and drug metabolism − other enzymes were the most significantly enriched pathways of DEmRNAs in OS. We constructed circRNA-miRNA-mRNA and protein–protein interaction (PPI) networks that may be associated with pathological processes of OS. Finally, we also revealed the pattern of tumor-infiltrating immune cells in OS and further explored the ceRNA networks we constructed in which we found that COL1A1 and RAN were significantly correlated with overall survival in patients with osteosarcoma (p in vivo and reveals a novel idea for understanding the pathogenesis of OS.

As of April 1, 2021, more than 2.8 million people have died of SARS-CoV-2 infection. In addition, the mutation of virus strains that have accompanied the pandemic has brought more severe challenges to pandemic control. Host microRNAs (miRNAs) are widely involved in a variety of biological processes of coronavirus infection, including autophagy in SARS-CoV-2 infection. However, the mechanisms underlying miRNAs involved in autophagy in SARS-CoV-2 infection have not been fully elucidated. In this study, the miRNA and messenger RNA (mRNA) expression profiles of patients with SARS-CoV-2 infection were investigated based on raw data from Gene Expression Omnibus (GEO) datasets, and potential novel biomarkers of autophagy were revealed by bioinformatics analyses. We identified 32 differentially expressed miRNAs and 332 differentially expressed mRNAs in patients with SARS-CoV-2 infection. Cytokine receptor related pathways were the most enriched pathways for differentially expressed miRNAs identified by pathway analysis. Most importantly, an autophagy interaction network, which was associated with the pathological processes of SARS-CoV-2 infection, especially with the cytokine storm, was constructed. In this network, hsa-miR-340-3p, hsa-miR-652-3p, hsa-miR-4772-5p, hsa-miR-192-5p, TP53INP2, and CCR2 may be biomarkers that predict changes in mild SARS-CoV-2 infection. Some molecules, including hsa-miR-1291 and CXCR4, were considered potential targets to predict the emergence of severe symptoms in SARS-CoV-2 infection. To our knowledge, this study provided the first profile analysis of an autophagy interaction network in SARS-CoV-2 infection and revealed several novel autophagy-related biomarkers for understanding the pathogenesis of SARS-CoV-2 infection in vivo.

Osteosarcoma (OS) is the most common type of bone cancer. Even with early diagnosis and aggressive treatment, the prognosis for OS is poor. In the present study, we investigated the proliferation and invasion inhibitory effect of apigenin on human OS cells and the possible molecular mechanisms involved. The cell viability of U2OS and MG63 human OS cell lines was detected by MTT assay. Cell cycle progression and invasion were assessed by flow cytometry and the Matrigel Boyden chamber assay, respectively, and the involvement of molecular mechanisms was examined by western blot analysis. We demonstrated that apigenin inhibited proliferation and reduced invasion in human OS cells, and downregulated the expression of β-catenin in OS cells. Furthermore, the inhibitory effect of apigenin on OS cells was reversed by overexpression of β-catenin, but enhanced by knockdown of β-catenin. Collectively, our results showed that apigenin inhibits the tumor growth of OS cells by inactivating Wnt/β-catenin signaling. Therefore, apigenin is a promising chemotherapeutic agent that may be used in the treatment of human OS.

Silk fibroin (SF) nanofibers, formed through electrospinning, have attractive utility in regenerative medicine due to the biocompatibility, mechanical properties and tailorable degradability. The mechanism of SF electrospun nanofiber formation was studied to gain new insight into the formation and control of nanofibers. SF electrospinning solutions with different nanostructures (nanospheres or nanofilaments) were prepared by controlling the drying process during the preparation of regenerated SF films. Compared to SF nanospheres in solution, SF nanofilaments had better spinnability with lower viscosity when the concentration of silk protein was below 10%, indicating a critical role for SF morphology, and in particular, nanostructures for the formation of electrospun fibers. More interesting, the diameter of electrospun fibers gradually increased from 50 nm to 300 nm as the increase in concentration of SF nanofilaments in the solution from 6% to 12%, implying size control by simply adjusting SF nanostructure and concentration. Aside from process parameters investigated in previous studies, such as SF concentration, viscosity and electrical potential, the present mechanism emphasizes significant influence of SF nanostructure on spinnability and diameter control of SF electrospun fibers, providing a controllable option for the preparation of silk-based electrospun scaffolds for biomaterials, drug delivery and tissue engineering needs.

To evaluate the difference between RetroButton and Interference Screw in Anterior Cruciate Ligament (ACL) Reconstruction.Ninety-seven patients with ACL rupture were treated by arthroscopic reconstruction with RetroButton and Interference Screw from June 2008 to December 2011. There were 54 males and 43 females with an average age of 27.5 years (range, 18-53 years). The preoperative magnetic resonance imaging (MRI) of all injured knees revealed the rupture of ACL. The average time from injury to surgery was 13.1 days (range, 6-20 days). All the patients were randomly divided into RetroButton group and Interference Screw group. And all the operations were performed under arthroscopy. Patients were instructed to walk with crutches and weight-bearing 4 weeks after operation. Walk without crutches was allowed 6 to 8 weeks after reconstruction and normal daily activities were gradually resumed.The average follow-up was 54.6 months (range 48-60 months). No adverse biological reactions or infection ever occurred. There was no spontaneous rupture or laxity of graft. The average Lysholm knee score[(56.1 ± 7.9) vs (93.1 ± 6.1); (55.3 ± 8.5) vs (93.2 ± 5.7)], KT-1000 examination [(9.2 ± 1.8) vs (2.1 ± 1.4); (9.5 ± 1.7) vs (2.1 ± 1.5)], International Knee Documentation Committee (IKDC) subjective and objective score [(49.7 ± 5.9) vs (91.7 ± 5.0); (50.2 ± 6.3) vs (91.0 ± 6.1)] were improved significantly in both two groups (all P0.01), and there was no significant difference between the two groups [(93.1 ± 6.1) vs (93.2 ± 5.7), P0.05].ACL reconstruction using RetroButton and Interference Screw are simple and effective, and can lead to good ligamentous stability and knee function. The two kinds of fixation methods have no significant difference in short and medium term effect. Long-term follow-up should be performed to confirm the durable stability of the knee.

Vascularization is fundamental for bone formation and bone tissue homeostasis. However, in human subjects, a direct molecular relationship has not been identified between angiogenesis and agents that promote bone disease or factors related to age. Osteopenia is a condition in which bone mineral density is lower than normal, and it represents a sign of normal aging. Here we tested whether the type H vessel, which was recently identified as strongly positive for CD31 and Endomucin (CD31hiEmcnhi) in mice, is an important indicator of aging and osteopenia in human subjects. We found that age-dependent losses of type H vessels in human bone sections conform to the observations in aged mice. The abundance of human type H vessels and osteoprogenitors may be relevant to changes in the skeletal microarchitecture and advanced osteopenia. Furthermore, ovariectomized mice, a widely used model for postmenopausal osteoporosis, exhibited significantly reduced type H vessels accompanied by reduced osteoprogenitors, which is consistent with impaired bone microarchitecture and osteoporosis, suggesting that this feature is an indicator of bone mass independent of aging. More importantly, administration of desferrioxamine led to significantly increased bone mass via enhanced angiogenesis and increased type H vessels in ovariectomized mice. Altogether, these data represent a novel finding that type H vessels are regulated in aged and osteopenia subjects. The abundance of human type H vessels is an early marker of bone loss and represents a potential target for improving bone quality via the induction of type H vessels.

Great controversy exists regarding the biologic responses of osteoblasts to X-ray irradiation, and the mechanisms are poorly understood. In this study, the biological effects of low-dose radiation on stimulating osteoblast proliferation, differentiation and fracture healing were identified using in vitro cell culture and in vivo animal studies. First, low-dose (0.5 Gy) X-ray irradiation induced the cell viability and proliferation of MC3T3-E1 cells. However, high-dose (5 Gy) X-ray irradiation inhibited the viability and proliferation of osteoblasts. In addition, dynamic variations in osteoblast differentiation markers, including type I collagen, alkaline phosphatase, Runx2, Osterix and osteocalcin, were observed after both low-dose and high-dose irradiation by Western blot analysis. Second, fracture healing was evaluated via histology and gene expression after single-dose X-ray irradiation, and low-dose X-ray irradiation accelerates fracture healing of closed femoral fractures in rats. In low-dose X-ray irradiated fractures, an increase in proliferating cell nuclear antigen (PCNA)-positive cells, cartilage formation and fracture calluses was observed. In addition, we observed more rapid completion of endochondral and intramembranous ossification, which was accompanied by altered expression of genes involved in bone remodeling and fracture callus mineralization. Although the expression level of several osteoblast differentiation genes was increased in the fracture calluses of high-dose irradiated rats, the callus formation and fracture union were delayed compared with the control and low-dose irradiated fractures. These results reveal beneficial effects of low-dose irradiation, including the stimulation of osteoblast proliferation, differentiation and fracture healing, and highlight its potential translational application in novel therapies against bone-related diseases.

The purpose of the present study was to investigate the effects of bafilomycin A1 (BafA1) on proliferation, apoptosis and autophagy in MG63 osteosarcoma cells. The growth rate of MG63 cells was determined using a Cell Counting Kit‑8 assay. The mitochondrial membrane potential (Δψ) was measured using a fluorescent probe, JC‑1, and the inhibition of autophagy and apoptosis was monitored by transmission electron microscopy. In addition, the inhibition of autophagy was monitored by western blot analysis of microtubule‑associated protein 1 light chain 3 (LC3), and the ratio of LC3‑II/LC3‑I protein levels was calculated as an indicator of the extent of autophagy. Furthermore, the expression levels of specific proteins associated with autophagy, including p53, Beclin1 and p62, were detected in cultured MG63 cells by western blotting. It was shown that the viability of MG63 cells was inhibited following the use of BafA1, and an induction in the expression levels of the apoptosis‑related protein p53 and the autophagic protein Beclin1 was detected. Furthermore, a collapse in Δψ was observed, together with an induction of apoptotic cell death, following treatment with BafA1. Therefore, following BafA1‑mediated inhibition of autophagy, the inhibition of MG63 cell proliferation and induction of apoptosis were observed.

Osteosarcoma shows resistance to chemotherapy and many side effects. The ethyl acetate fraction of ethanolic extract of Chrysophyllum cainito was taken in the present work. The extract was characterized for its phenolic content, antioxidant capacity (ferric reducing antioxidant power and 2,2-diphenyl-1-picrylhydrazyl assays), ability to form reactive oxygen species and annexin V assay. The extract contained phenolic content of 30.1 ± 0.2 mg GAE/g extract. Ferric reducing antioxidant power assay and DPPH assay showed 213.2 ± 12.4 mM Fe2+ equivalent per gram extract and 85.6 ± 4.9 TE/g respectively. For production of reactive oxygen species in the osteosarcoma cells, extract at 50 µg GAE/mLconcentration was statistically equivalent to 100 µM H2O2. EC50 of extract was calculated to be 133 µg GAE/mL in cell viability studies.