Objectives: The aim of this study was to investigate the effects of exosomes isolated from human bone marrow mesenchymal stem cells (BMSCs) on osteoarthritis (OA) and a competitive endogenous RNA (ceRNA) network.Methods: Exosomes were isolated from human BMSCs and characterized by transmission electron microscopy (TEM), Nanosight (NTA), and western blotting. Chondrocytes were treated with interleukin-1β (IL-1β) and then transfected with exosomes. Cell viability and apoptosis were determined using Cell Counting Kit-8 (CCK-8) and flow cytometry, respectively. Cells with IL-1β and exosomes were sequenced, and differentially expressed lncRNAs (DE-lncRNAs) and miRNAs (DE-miRNAs) were identified. Thereafter, a ceRNA network (LYRM4-AS1-GRPR-miR-6515-5p) was chosen for further validation.Results: TEM, NTA, and western blotting showed that exosomes were successfully isolated, and PKH67 staining showed that exosomes could be taken up by IL-1β-induced chondrocytes. Compared with the control group, IL-1β significantly decreased cell viability and promoted apoptosis (P < 0.05), while exosomes reversed the changes induced by IL-1β. For MMP3, AKT, and GRPR, IL-1β upregulated their expression, while exosomes downregulated their expression. For PTEN, there was no significant difference in PTEN expression between the control and IL-1β groups; however, exosomes markedly upregulated PTEN expression. By sequencing, 907 DE-lncRNAs and 25 DE-miRNAs were identified, and a ceRNA network was constructed. The dual-luciferase reporter gene indicated that LYRM4-AS1, miR-6515-5, and GRPR interacted with each other. The results of cell experiments showed that LYRM4-AS1 regulated the growth of IL-1β-induced chondrocytes by GRPR/miR-6515-5p.Conclusion: Exosomes may alleviate OA inflammation by regulating the LYRM4-AS1/GRPR/miR-6515-5p signaling pathway.

An increasing body of evidence indicates that microRNAs (miRNAs), a class of small non‑coding RNAs, are often aberrantly expressed in human osteosarcoma. This study aimed to investigate the effects of miR‑25 and to identify its potential target genes in osteosarcoma (OS) cells. First, the expression of miR‑25 was detected by reverse transcription‑quantitative polymerase chain reaction (RT-qPCR), which revealed a significant upregulation of miR‑25 in osteosarcoma tissues compared to the adjacent healthy tissues. To investigate the role of miR‑25 in osteosarcoma cell proliferation, the miR‑25 precursor was next transfected into Saos‑2 and U2OS cells. Overexpression of miR‑25 promoted cell proliferation in vitro and tumor growth in a xenograft mouse model. In addition, our results revealed that the protein expression of p27, a cell‑cycle inhibitor, is negatively regulated by miR‑25. Restoring the p27 level in miR‑25‑overexpressing cells reversed the enhancing effect of miR‑25 on cell proliferation. Therefore, miR‑25 may act as an onco‑miRNA in osteosarcoma, which provides new perspectives in cancer treatment strategies based on molecular targeting.

Recent reports suggest that staphylococcal exotoxins, acting as superantigens, activate T cells with subsequent massive proliferation, thereby contributing to the etiology of chronic rhinosinusitis with nasal polyps (CRSwNP). The objectives of this study are (1) to demonstrate directly the presence of staphylococcal exotoxins in nasal mucosa and sinonasal polyp tissue, and (2) provide indirect evidence of the effect of superantigens on the T cells expressing the target of superantigen, i.e., the β variable chain receptor (TCRBV) in polyp tissue and peripheral blood of patients with CRSwNP. Sinonasal polyp tissue and peripheral blood specimens were obtained from 37 patients with chronic rhinosinusitis (22 patients with bilateral nasal polyps, 15 without nasal polyps) and 12 normal subjects for comparative negative controls. Tissue specimens were assayed by enzyme-linked immunosorbent assay (ELISA) for the most common staphylococcal exotoxins (A–D) and toxic shock syndrome toxin type 1. Fresh tissue and blood samples were analyzed by flow cytometry to determine the expression of TCRBV. In the CRSwNP subjects 12 of 22 samples (54.54%) demonstrated reactivity for at least 1 staphylococcal exotoxin, while 2 of the 12 were positive for 2 toxins. There were no positive results in the CRS without nasal polyps or control groups. There was a clear trend of increased TCRBV expression in the ELISA-positive group both for tissue and blood specimens. Staphylococcal superantigens were present in the nasal cavity of patients with CRSwNP with a high percentage of TCRBV, which suggests the possibility of superantigens as etiological agents of CRSwNP.