LINC00467 mediates the 5-fluorouracil resistance in breast cancer cells.

Breast cancer is a prevalent global disease that requires the development of effective therapeutic approaches. The occurrence of 5-fluorouracil (5-FU) resistance in breast cancer is emerging, which urgently needs new way to overcome the obstacle. In this study, we validated that the expression of LINC00467 is up-regulated in the breast cancer patients and breast cancer cells. In addition, the high expression of LINC00467 is associated with the 5-FU resistance of breast cancer cells. Interestingly, LINC00467 induced the homologous recombination (HR) repair via promoting the expression of NBS1 in 5-FU resistant breast cancer cells. Furthermore, miR-205 was validated as a common target of LINC00467 and NBS1, indicating that LINC00467 may induce NBS1 via the miRNA-mRNA target. Importantly, we identified that XBP1, as a transcription factor, induced the expression of LINC00467, which resulted in the enhanced HR efficiency and 5-FU resistance. Silencing XBP1 sensitized the 5-FU resistant breast cancer cells to the 5-FU treatment, whereas the ectopic expression of LINC00467 abrogated the effect of XBP1 silencing. In conclusion, LINC00467 enhances the 5-FU resistance by inducing NBS1-mediated DNA repair. LINC00467 also mediates the function of XBP1 in 5-FU resistance in breast cancer cells.

TLR9 regulates the autophagy-lysosome pathway to promote dendritic cell maturation and activation by activating the TRAF6-cGAS-STING pathway.

Dysregulated maturation and activation of dendritic cells (DCs) play a significant role in the progression of systemic lupus erythematosus (SLE). The autophagy-lysosome pathway has been identified as a potential mechanism to inhibit DC activation and maturation, but its precise workings remain unclear. We investigated the role and regulatory mechanism of TLR9 in modulating the autophagy-lysosome pathway and DCs activation. The mRNA and protein expressions were assessed using qRT-PCR and/or western blot. NZBW/F1 mice was used to construct a lupus nephritis (LN) model in vivo. Cell apoptosis was analyzed by TUNEL staining. Flow cytometry was adopted to analyze DCs surface markers. Lyso-tracker red staining was employed to analyze lysosome acidification. Levels of anti-dsDNA, cytokines, C3, C4, urine protein and urine creatinine were examined by ELISA. The results showed that TLR9 was markedly increased in SLE patients, and its expression was positively correlated with SLEDAI scores and dsDNA level. Conversely, TLR9 expression showed a negative correlation with C3 and C4 levels. Loss-of function experiments demonstrated that TLR9 depletion exerted a substantial inhibition of renal injury, inflammation, and DCs numbers. Additionally, upregulation of TLR9 promoted DCs maturation and activation through activation of autophagy and lysosome acidification. Further investigation revealed that TLR9 targeted TRAF6 to activate the cGAS-STING pathway. Rescue experiments revealed that inactivation of the cGAS/STING signaling pathway could reverse the promoting effects of TLR9 upregulation on DCs maturation, activation, and autophagy-lysosome pathway. Overall, our findings suggested that TLR9 activated the autophagy-lysosome pathway to promote DCs maturation and activation by activating TRAF6-cGAS-STING pathway, thereby promoting SLE progression.

Interaction between rheumatoid arthritis and mediterranean diet on the risk of cardiovascular disease for the middle aged and elderly from National Health and Nutrition Examination Survey (NHANES).

BACKGROUND: Cardiovascular diseases (CVD) occurrence were associated with rheumatoid arthritis (RA) and Mediterranean diet (MD), but few studies have been conducted to explore the combined effect. This study was to outline the relationship of coexistence of RA and MD on the risk of CVD based on the National Health and Nutrition Examination Survey (NHANES) database. METHODS: The data of this cross-sectional study was from the NHANES 2005-2010. The definition of CVD and RA was based on the self-reported questions, respectively; and the alternate MD Index assessed all participants' adherence to the MD. Weighted multivariate logistic regression was adopted to explore the relationship of RA, MD on the risk of CVD, and coexistence effect of RA and MD. The additive interaction was evaluated by the relative excess risk due to interaction (RERI), attributable proportion (AP) and the synergy index (SI). The multiplicative interaction was evaluated by odds ratio (OR) and 95% confidence interval (CI) of product-term. RESULTS: A total of 3,352 participants from NHANES database who were divided into CVD group (n = 385) and non-CVD group (n = 2,967). The result indicated that RA (Model 1: OR = 3.98, 95%CI: 2.76-5.73; Model 2: OR = 2.65, 95%CI: 1.69-4.16) and low adherence to the MD (Model 1: OR = 1.82, 95%CI: 1.13-2.93; Model 2: OR = 1.67, 95%CI:1.01-2.77) was associated with an increased risk of CVD, respectively. Additionally, we observed the additive (RERI = 4.76, 95% CI: 0.52-9.00; AP = 0.74, 95% CI: 0.54-0.95; SI = 8.21, 95% CI: 1.48-45.51) and multiplicative (OR = 3.63, 95% CI: 1.44-9.15) interaction of RA and low adherence to the MD on the risk of CVD. CONCLUSION: RA and MD were associated with CVD occurrence, respectively, and there may be an interaction between RA and MD for the development of CVD.

SIRT1 is transcriptionally repressed by YY1 and suppresses ferroptosis in rheumatoid arthritis.

BACKGROUND: Sirtuin 1 (SIRT1) is reported downregulated in rheumatoid arthritis (RA), and the protective effects of SIRT1 on tissue damage and organ failure may be related to cellular ferroptosis. However, the exact mechanism by which SIRT1 regulates RA remains unclear. METHODS: Quantitative real-time PCR (qPCR) and western blot assays were performed to explore the expressions of SIRT1 and Yin Yang 1 (YY1). CCK-8 assay was used for cytoactive detection. The interaction between SIRT1 and YY1 was validated by dual-luciferase reporter gene assay and chromatin immunoprecipitation (ChIP). DCFH-DA assay and iron assay were applied to detect the reactive oxygen species (ROS) and iron ion levels. RESULTS: In the serum of RA patients, SIRT1 was downregulated, but YY1 was upregulated. In LPS-induced synoviocytes, SIRT1 could increase cell viability and decrease ROS and iron levels. Mechanistically, YY1 downregulated the expression of SIRT1 by inhibiting its transcription. YY1 overexpression partly revised the effects of SIRT1 on ferroptosis in synoviocytes. CONCLUSION: SIRT1 is transcriptionally repressed by YY1 and inhibits the ferroptosis of synoviocytes induced by LPS, so as to relieve the pathological process of RA. Therefore, SIRT1 might be a new diagnosis and therapeutic target of RA.

Alterations in the human oral microbiota in systemic lupus erythematosus.

BACKGROUND: Alterations in oral microbiota in patients with systemic lupus erythematosus (SLE) is less evaluated. The aim of this study was to compare the characteristics of the oral microbiome in SLE patients and healthy controls, and construct an SLE classifier based on the oral microbiota. METHODS: We sequenced tongue-coating samples of individuals in treatment-naïve SLE (n = 182) and matched healthy controls (n = 280). We characterized the oral microbiome and constructed a microbial classifier in the derivation cohort and validated the results in the validation cohorts. Furthermore, the oral microbiome of posttreatment SLE (n = 73) was characterized. RESULTS: The oral microbial diversity of SLE was increased, and the microbial community was different between SLE and healthy controls. The genera Prevotella and Veillonella were enriched, while Streptococcus and Porphyromonas were reduced in SLE. In addition, an increase was noted in 27 predicted microbial functions, while a decrease was noted in 34 other functions. Thirty-nine operational taxonomy units (OTUs) were identified to be related with seven clinical indicators. Two OTUs were identified to construct a classifier, which yielded area under the curve values of 0.9166 (95% CI 0.8848-0.9483, p < 0.0001), 0.8422 (95% CI 0.7687-0.9157, p < 0.0001), and 0.8406 (95% CI 0.7677-0.9135, p < 0.0001) in the derivation, validation, and cross-regional validation groups, respectively. Moreover, as disease activity increased, Abiotrophia and Lactobacillales increased, while Phyllobacterium and unclassified Micrococcusaceae decreased. Finally, nine OTUs were selected to construct a classifier distinguishing posttreatment SLE patients from healthy controls, which achieved a diagnostic efficacy of 0.9942 (95% CI 0.9884-1, p < 0.0001). CONCLUSIONS: Our study comprehensively characterizes the oral microbiome of SLE and shows the potential of the oral microbiota as a non-invasive diagnostic biomarker in SLE.

SIRT1 is transcriptionally repressed by YY1 and suppresses ferroptosis in rheumatoid arthritis

Abstract Background Sirtuin 1 (SIRT1) is reported downregulated in rheumatoid arthritis (RA), and the protective effects of SIRT1 on tissue damage and organ failure may be related to cellular ferroptosis. However, the exact mechanism by which SIRT1 regulates RA remains unclear. Methods Quantitative real-time PCR (qPCR) and western blot assays were performed to explore the expressions of SIRT1 and Yin Yang 1 (YY1). CCK-8 assay was used for cytoactive detection. The interaction between SIRT1 and YY1 was validated by dual-luciferase reporter gene assay and chromatin immunoprecipitation (ChIP). DCFH-DA assay and iron assay were applied to detect the reactive oxygen species (ROS) and iron ion levels. Results In the serum of RA patients, SIRT1 was downregulated, but YY1 was upregulated. In LPS-induced synoviocytes, SIRT1 could increase cell viability and decrease ROS and iron levels. Mechanistically, YY1 downregulated the expression of SIRT1 by inhibiting its transcription. YY1 overexpression partly revised the effects of SIRT1 on ferroptosis in synoviocytes. Conclusion SIRT1 is transcriptionally repressed by YY1 and inhibits the ferroptosis of synoviocytes induced by LPS, so as to relieve the pathological process of RA. Therefore, SIRT1 might be a new diagnosis and therapeutic target of RA. Highlights Combining SIRT1 with synoviocytes ferroptosis in rheumatoid arthritis for the first time. The transcription factor YY1 combined to the SIRT1 promoter in synovial cells and inhibited its expression and functional roles. The inhibition of SIRT1 with YY1 decreased the ferroptosis in synoviocytes.

Anderson localization and multifractal spectrum at the transition point in a two-dimensional non-Hermitian AII†system.

The Anderson localization transition in a two-dimensional AII†system is studied by eigenvalue statistics and then confirmed by the multifractal analysis of the wave functions at the transition point. The system is modeled by a two-dimensional lattice structure with real-quaternion off-diagonal elements and complex on-site energies, whose real and imaginary parts are two independent random variables. Via finite-size scaling analysis of eigenvalue spacing ratios, we find the non-Hermiticity reduces the critical disorder and give an estimate of the critical exponentν= 1.89, showing the system belongs to a new universal class other than the AII class and probably shares the same exponent with two-dimensional Hermitian DIII systems although they have different symmetries. The Anderson localization transition is further confirmed by checking the linearity in the parametric representation of the singularity strength and by checking the universality of the forms of the singularity spectra of different system sizes. The generalized dimensions are obtained asD1=1.80andD2=1.62.

OX40-Fc Fusion Protein Alleviates PD-1-Fc-Aggravated Rheumatoid Arthritis by Inhibiting Inflammatory Response.

BACKGROUND: Researches have confirmed that the abnormal signals of OX40 and PD-1 lead to the changes of T cell biological behavior, thus participating the immunopathological process of RA. However, the pathogenesis of RA immunopathological process has not been clarified yet. METHODS: 30 DBA/1 mice were randomly divided into 5 groups (6 mice per group): control group, collagen-induced arthritis (CIA) group, PD-1-Fc/CIA group, OX40-Fc/CIA group, and PD-1-Fc + OX40-Fc/CIA group. The pathological changes in mice joints were observed by H&E staining. The proportion of CD4+ T, CD8+ T, CD28+, and CD19+ cells in peripheral blood mononuclear cells (PBMCs) was detected by flow cytometry. Serum inflammatory factors (CRP, IL-2, IL-4, IL-1ß, INF-γ) and bone metabolism-related genes (CTX-I, TRACP-5b, BALP) were detected by ELISA assay. Western blotting was applied to measure the NF-κB signaling pathway-related protein (p-IKKß, p-IκBα, p50) expression in synovial tissue of mice joint. RESULTS: Compared with the control group, CIA mice showed significant increases in arthritis score and pathological score. In the CIA group, a marked decrease was identified in the proportion of CD8+ T, CD19+, and CD68+ cells. Additionally, the CIA group was associated with upregulation of secretion of inflammatory factors in serum and expression of bone metabolism-related genes and NF-κB pathway-related proteins. Compared with the CIA group, the same indexes above showed a further aggravation in the PD-1-Fc group while all indexes improved in the OX40-Fc group. Besides, OX40-Fc fusion protein slowed down significantly the further deterioration of CIA mouse pathological process caused by PD-1-Fc fusion protein. CONCLUSION: OX40-Fc fusion protein alleviates PD-1-Fc-aggravated RA by inhibiting inflammatory response. This research provides biological markers with clinical significance for diagnosis and prognosis of RA, as well as offers theoretical and experimental foundation to the new targets for immune intervention.

LncRNA GAS5 alleviates rheumatoid arthritis through regulating miR-222-3p/Sirt1 signalling axis.

INTRODUCTION: Rheumatoid arthritis (RA) is an autoimmune disease that affects millions of people. Fibroblast-like synoviocytes (FLSs) located in rheumatoid panni play a pivotal role in the formation of RA. The long noncoding RNA (lncRNA) GAS5 is reportedly downregulated in rheumatoid arthritis. However, its detailed mechanism in RA remains to be explored. This study investigated the roles and related mechanisms of GAS5 in RA. METHODS: The expression levels of GAS5, miR-222-3p, and sirtuin 1 (Sirt1) were evaluated by quantitative PCR (qPCR). Cell proliferation was analyzed by CCK-8 and BrdU assays. Cell apoptosis was assessed by flow cytometry and western blotting. Enzyme-linked immunosorbent assay (ELISA) was utilized to evaluate the levels of TNF-α, IL-1ß, and IL-6. The interaction between GAS5 or Sirt1 and miR-222-3p was predicted by starBase and validated by dual-luciferase reporter assay. RESULTS: GAS5 expression was found to be downregulated in the serum samples of RA patients and in RA-FLSs. GAS5 overexpression or the inhibition of miR-222-3p impeded the activity of RA-FLSs by repressing their proliferation and inflammation and by promoting apoptosis. Mechanistically, GAS5 indirectly regulates Sirt1 expression by binding miR-222-3p. Further experiments confirmed that Sirt1 overexpression restored the anti-RA activity of GAS5 under miR-222-3p mimic. CONCLUSIONS: The miR-222-3p/Sirt1 axis was found to be critical for the function of GAS5 in regulating the proliferation, inflammation, and apoptosis of RA-FLSs. These data indicate GAS5 activation as a potential therapeutic strategy for RA progression.

Immune Function and Mechanism of Costimulating Molecules PD-1 and OX40 in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a T lymphocyte-mediated autoimmune disease, although its immune mechanism has not been fully studied. In this study, healthy controls (HC), osteoarthritis patients (OA), and RA patients were enrolled, and mice were evenly divided into control, collagen-induced arthritis (CIA), PD-1 Fc/CIA (PD-1 Fc membrane fusion protein administered to CIA mice), OX40 Fc/CIA (OX40 Fc membrane fusion protein administered to CIA mice), and PD-1 Fc + OX40 Fc/CIA groups. The expressions of programmed death-1 (PD-1) and OX40 in CD4+ T lymphocytes and the levels of sPD-1, immunoglobulin, and proinflammatory factors in patients and mice were measured. The results showed that the expression levels of PD-1 and OX40 in CD4+ T lymphocytes separated from the peripheral blood and synovial fluid of RA patients and the spleen of CIA mice were observably elevated. The levels of soluble PD-1, interleukin (IL)-2, IL-4, IL-5, IL-17, and interferon-γ (IFN-γ) in RA patients obviously increased. In animal experiments, PD-1 Fc not only increased the serum levels of immunoglobulin G (IgG), IgG1, and IgG2a in CIA mice, but also increased the levels of IL-4, IL-2, IL-5, IL-17, and IFN-γ in mouse spleen cells and joint tissues, which, however, were reversed by OX40 Fc. In conclusion, OX40 inhibition could reverse the progression of RA caused by PD-1 blocking, and PD-1 might be a potential target for RA. Clinical Trials.gov ID: HGH2018012203.