Long non-coding RNA cancer susceptibility candidate 2 regulates the function of human fibroblast-like synoviocytes via the microRNA-18a-5p/B-cell translocation gene 3 signaling axis in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a perennial inflammatory condition. Preliminary research indicated that long non-coding (lnc)RNA cancer susceptibility candidate 2 (CASC2) was downregulated in the serum of RA patients. Our study was designed to reveal the roles of lncRNA CASC2 in RA and the latent mechanisms underlying its role. Bioinformatics method (Starbase) and dual-luciferase reporter assay revealed that microRNA (miR)-18a-5p directly interacted with lncRNA CASC2. Furthermore, lncRNA CASC2 and miR-18a-5p expression in the serum samples of RA patients and healthy controls were measured via reverse transcription-quantitative PCR. Compared with the healthy subjects, lncRNA CASC2 was downregulated, whereas miR-18a-5p was upregulated in patients with RA. Overexpression of lncRNA CASC2 decreased the viability of human fibroblast-like synoviocytes (HFLSs) and induced apoptosis, as revealed by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and flow cytometry analyses. Furthermore, the Western blotting assay suggested that Bax was upregulated and Bcl-2 was downregulated in lncRNA CASC2 up-regulated HFLSs. Downregulation of tumor necrosis factor alpha (TNF-α), interleukin (IL)-1ß, IL-6, matrix metalloproteinase (MMP)1, and MMP3 levels by lncRNA CASC2 up-regulation was determined using enzyme-linked immunosorbent assays (ELISAs). However, HFLSs co-transfected with miR-18a-5p mimic exhibited opposite effects compared with the case for the overexpression of lncRNA CASC2. The aforementioned methods were used to verify that a binding site exists between B-cell translocation gene 3 (BTG3) and miR-18a-5p. The effects of miR-18a-5p inhibitor on HFLSs were reversed by BTG3 silencing. Overall, lncRNA CASC2 alleviated RA by adjusting the miR-18a-5p/BTG3 signaling axis and could serve as a novel therapeutic option for RA.

LncRNA ZNF667-AS1 alleviates rheumatoid arthritis by sponging miR-523-3p and inactivating the JAK/STAT signalling pathway.

BACKGROUND: Rheumatoid arthritis (RA) is an autoimmune disease, which compromises the synovial membrane resulting in chronic inflammation. Increasing evidence has demonstrated that long non-coding RNAs (lncRNAs) are implicated in the pathogenesis of RA. This study investigated the role of lncRNA ZNF667-AS1 in RA progression. METHODS: Synovial tissues and fibroblast-like synoviocytes (FLSs) were obtained from patients with RA. Gene expression was measured using RT-qPCR. Chondrocytes were treated with lipopolysaccharide (LPS) to establish in vitro models of OA. Cell counting kit-8 (CCK-8), western blot, and enzyme-linked immunosorbent assay (ELISA) were used to examine the proliferation and inflammatory cytokine production in chondrocytes. Animal models of OA were established in SD rats. Peripheral blood mononuclear cells (PBMCs) were isolated from the OA rats. Flow cytometry was used to measure the changes of the inflammatory T-helper cell 17 (Th17) cells. The relationship between ZNF667-AS1 and miR-523-3p was verified by luciferase reporter assay. RESULTS: ZNF667-AS1 was downregulated in RA-FLSs and LPS-stimulated chondrocytes. ZNF667-AS1 overexpression significantly promoted cell proliferation and inhibited the production of IL-6, IL-17 and TNF-α in LPS-stimulated chondrocytes. Additionally, ZNF667-AS1 overexpression reduced the generation of CD4 + IL-17+ cells. In mechanism, ZNF667-AS1 acted a sponge for miR-523-3p. MiR-523-3p overexpression reversed the ZNF667-AS1-mediated regulation of cell proliferation and inflammation. Furthermore, miR-523-3p overexpression abolished the inhibitory effects of ZNF667-AS1 on the JAK/STAT signalling activation. CONCLUSION: ZNF667-AS1 exerts protective effects during RA development by sponging miR-523-3p and inactivating the JAK/STAT signalling.

Case Report: A Re-Positive Case of SARS-CoV-2 Associated With Glaucoma.

The current pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has already become a global threat to the human population. Infection with SARS-CoV-2 leads to a wide spectrum of clinical manifestations. Ocular abnormalities have been reported in association with COVID-19, but the nature of the impairments was not specified. Here, we report a case of a female patient diagnosed with glaucoma on re-hospitalization for ocular complications two months after being discharged from the hospital upon recovery from COVID-19. Meanwhile, the patient was found re-positive for SARS-CoV-2 in the upper respiratory tract. The infection was also diagnosed in the aqueous humor through immunostaining with antibodies against the N protein and S protein of SARS-CoV-2. Considering the eye is an immune-privileged site, we speculate that SARS-CoV-2 survived in the eye and resulted in the patient testing re-positive for SARS-CoV-2.

Sustainability of SARS-CoV-2 Induced Humoral Immune Responses in COVID-19 Patients from Hospitalization to Convalescence Over Six Months.

Understanding the persistence of antibody in convalescent COVID-19 patients may help to answer the current major concerns such as the risk of reinfection, the protection period of vaccination and the possibility of building an active herd immunity. This retrospective cohort study included 172 COVID-19 patients who were hospitalized in Wuhan. A total of 404 serum samples were obtained over six months from hospitalization to convalescence. Antibodies in the specimens were quantitatively analyzed by the capture chemiluminescence immunoassays (CLIA). All patients were positive for the anti-SARS-CoV-2 IgM/IgG at the onset of COVID-19 symptoms, and the IgG antibody persisted in all the patients during the convalescence. However, only approximately 25% of patients can detect the IgM antibodies, IgM against N protein (N-IgM) and receptor binding domain of S protein (RBD-IgM) at the 27th week. The titers of IgM, N-IgM and RBD-IgM reduced to 16.7%, 17.6% and 15.2% of their peak values respectively. In contrast, the titers of IgG, N-IgG and RBD-IgG peaked at 4-5th week and reduced to 85.9%, 62.6% and 87.2% of their peak values respectively at the end of observation. Dynamic behavior of antibodies and their correlation in age, gender and severity groups were investigated. In general, the COVID-19 antibody was sustained at high levels for over six months in most of the convalescent patients. Only a few patients with antibody reducing to an undetectable level which needs further attention. The humoral immune response against SARS-CoV-2 infection in COVID-19 patients exhibits a typical dynamic of acquired immunity.