Zhixin Xue

A hallmark of systemic lupus erythematosus is high titers of circulating autoantibodies. Recently, a novel CD11c+ B-cell subset has been identified that is critical for the development of autoimmunity. However, the role of CD11c+ B cells in the development of lupus is unclear. Chronic graft-versus-host disease (cGVHD) is a lupus-like syndrome with high autoantibody production. The purpose of this study was to explore the role of CD11c+ B cells in the pathogenesis of lupus in cGVHD mice. cGVHD was induced by an intraperitoneal injection of 5 × 107 Bm12 splenocytes into B6 mice. Flow cytometry was used to analyze mice splenocytes and human samples. Magnetic beads were used to isolate mice B cells. Gene expression was determined by real-time quantitative polymerase chain reaction (RT-qPCR). Enzyme-linked immunosorbent assay (ELISA) was used to detect antibodies in serum and supernatants. The percentage and absolute number of CD11c+ B cells was increased in cGVHD-induced lupus, with elevated levels of antichromatin immunoglobulin (Ig)G and IgG2a in sera. CD11c+ plasma cells from cGVHD mice produced large amounts of antichromatin IgG2a upon stimulation. Depletion of CD11c+ B cells reduced antichromatin IgG and IgG2a production. T-bet was upregulated in CD11c+ B cells. Knockout of T-bet in B cells alleviated cGVHD-induced lupus. Importantly, the percentage of T-bet+CD11c+ B cells increased in lupus patients and positively correlated with serum antichromatin levels. T-bet+CD11c+ B cells promoted high antichromatin IgG production in the lupus-like disease model cGVHD. In lupus patients, the percentage of T-bet+CD11c+ B cells was elevated and positively correlated with antichromatin antibodies. The findings provide potential therapeutic insight into lupus disease treatment.

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by augmented type I interferon signaling. High-throughput technologies have identified plenty of SLE susceptibility single-nucleotide polymorphisms (SNPs) yet the exact roles of most of them are still unknown. Functional studies are principally focused on SNPs in the coding regions, with limited attention paid to the SNPs in non-coding regions. Long non-coding RNAs (lncRNAs) are important players in shaping the immune response and show relationship to autoimmune diseases. In order to reveal the role of SNPs located near SLE related lncRNAs, we performed a transcriptome profiling of SLE patients and identified linc00513 as a significantly over expressed lncRNA containing functional SLE susceptibility loci in the promoter region. The risk-associated G allele of rs205764 and A allele of rs547311 enhanced linc00513 promoter activity and related to increased expression of linc00513 in SLE. We also identified linc00513 to be a novel positive regulator of type I interferon pathway by promoting the phosphorylation of STAT1 and STAT2. Elevated linc00513 expression positively correlated with IFN score in SLE patients. Linc00513 expression was higher in active disease patients than those inactive ones. In conclusion, our data identify two functional promoter variants of linc00513 that contribute to increased level of linc00513 and confer susceptibility on SLE. The study provides new insights into the genetics of SLE and extends the role of lncRNAs in the pathogenesis of SLE.

Objective: Lupus nephritis (LN) is one of the most serious complications of systemic lupus erythematosus (SLE). Type I interferon (IFN-I) is associated with the pathogenesis of LN. Long non-coding RNAs (lncRNAs) have been implicated in the pathogenesis of SLE, however, the roles of lncRNAs in LN are still poorly understood. Here, we identified and investigated the function of LN-associated lncRNA RP11-2B6.2 in regulating IFN-I signaling pathway. Methods: RNA sequencing was used to analyze the expression of lncRNAs in kidney biopsies from LN patients and controls. Antisense oligonucleotides and CRISPRi system or overexpression plasmids and CRISPRa system were used to perform loss or gain of function experiments. In situ hybridization, imaging flow cytometry, dual-luciferase reporter assay, and ATAC sequencing were used to study the functions of lncRNA RP11-2B6.2. RT-qPCR, ELISA, and western blotting were done to detect RNA and protein levels of specific genes. Results: Elevated lncRNA RP11-2B6.2 was observed in kidney biopsies from LN patients and positively correlated with disease activity and IFN scores. Knockdown of lncRNA RP11-2B6.2 in renal cells inhibited the expression of IFN stimulated genes (ISGs), while overexpression of lncRNA RP11-2B6.2 enhanced ISG expression. Knockdown of LncRNA RP11-2B6.2 inhibited the phosphorylation of JAK1, TYK2, and STAT1 in IFN-I pathway, while promoted the chromatin accessibility and the transcription of SOCS1. Conclusion: The expression of lncRNAs is abnormal in the kidney of LN. LncRNA RP11-2B6.2 is a novel positive regulator of IFN-I pathway through epigenetic inhibition of SOCS1, which provides a new therapeutic target to alleviate over-activated IFN-I signaling in LN.

Objective To compare the effectiveness and safety of tofacitinib versus calcineurin inhibitor (CNI) as initial immunosuppressive regimen for anti-melanoma differentiation-associated gene 5-positive dermatomyositis with interstitial lung disease (MDA5 + DM-ILD). Methods Adult Chinese patients with newly diagnosed MDA5 + DM-ILD (ILD course <3 months) from five tertiary referral centres between April 2014 and January 2023 were included in this retrospective cohort study. The primary effectiveness end-point was lung transplantation-free survival within 1 year. Propensity score-based inverse probability of treatment weighting (IPTW) was applied for adjustment in this real-world study. Results In the eligible cohort, a total of 94 (32.4%) and 105 (46.7%) patients died or underwent lung transplantation within 1 year in the tofacitinib group (n=290) and the CNI group (n=225), respectively. After adjustment by IPTW, patients’ lung transplantation-free survival rate within 1 year was significantly higher in the tofacitinib group compared to the CNI group (log-rank p=0.013). Multivariable Cox analysis performed in the IPTW dataset revealed that the hazard ratio of tofacitinib versus CNI for 1-year survival was 0.72 (95% CI 0.56–0.94; p=0.013). The adjusted difference of survival rate was 9.3% (95% CI 2.8–15.8%). Alternative analytic strategies yielded consistent results in sensitivity analyses. Patients aged <60 years, without rapidly progressive ILD, or with baseline arterial oxygen tension/inspiratory oxygen fraction ≥300 mmHg might benefit more from tofacitinib. Opportunistic infection was the major treatment-related serious adverse event, with generally comparable incidence (42.4% versus 45.3%). Conclusion In this large multicentre cohort study, tofacitinib showed significantly more benefits for 1-year lung transplantation-free survival than calcineurin inhibitors in MDA5 + DM-ILD.