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Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by abnormal activation of T cells and caused by an imbalance in the production and clearance of apoptotic cells. We previously showed that the transcription regulator Bach2 regulated abnormal B‐cell activation in SLE. Here, we investigated whether Bach2 was also involved in Th9 cell differentiation in SLE. We found that the proportion of Th9 cells was enhanced in the peripheral blood mononuclear cells (PBMC) of SLE patients. The PBMC and CD4+ T cells of SLE patients exhibited a decrease of Bach2 expression and an increase of IL‐9 expression. Furthermore, Bach2 overexpression significantly repressed the levels of PU.1, IRF4, IL‐9, and Th9 cells in the CD4+ T cells of SLE patients and healthy volunteers. In addition, Bach2 overexpression inhibited the levels of IL‐9 and Th9 cells, whereas IRF4 upregulation enhanced the levels of IRF4 and IL‐9 and Th9 cells in the CD4+ T cells of SLE patients and healthy volunteers. The effect of IRF4 up‐regulation was abolished by Bach2 overexpression. In summary, our work suggests that Bach2 overexpression represses Th9 cell differentiation by suppressing IRF4 expression in SLE, and thus, Bach2 may be a novel potential target for SLE treatment. [ABSTRACT FROM AUTHOR]

Single‐nucleotide polymorphisms (SNPs) in the UHRF gene have been shown to be associated with systemic lupus erythematosus (SLE) in European and Hong Kong Chinese, but statistically significant evidence for association has not been found in a mainland Han Chinese population. Therefore, we selected SNP rs13205210 located in UHRF1BP1 as a candidate association from our previously published genome‐wide association study (GWAS) data of SLE (1,047 cases and 1,205 controls from a mainland Han Chinese population) to explore the association between the UHRF1BP1 gene and SLE. We conducted a large‐scale replication study in an additional independent sample of 3,509 cases and 8,246 controls from a mainland Han Chinese population. Real‐time PCR was used to determine gene expression differences in peripheral blood mononuclear cells (PBMCs) from cases and controls. As a result, we replicated the association between the UHRF1BP1 gene and SLE (rs13205210, missense, Pmeta = 2.26E‐17, odds ratio = 1.41) by a meta‐analysis of our previous GWAS and this replication study involving a total of 4,556 cases and 9,451 controls. The UHRF1BP1 mRNA expression level in PBMCs was significantly decreased in patients with SLE compared with that in healthy controls. SNP rs13205210 exhibited an expression quantitative trait loci effect on the UHRF1BP1 gene in PBMCs from patients. In conclusion, this study not only suggests that the UHRF1BP1 gene was associated with SLE in a mainland Han Chinese population, but also implied that it might be a common genetic factor contributing to SLE susceptibility in multiple populations. [ABSTRACT FROM AUTHOR]

Objective: Genome-wide association studies (GWAS) have identified >100 risk loci for systemic lupus erythematosus (SLE), but the disease genes at most loci remain unclear, hampering translation of these genetic discoveries. We aimed to prioritise genes underlying the 110 SLE loci that were identified in the latest East Asian GWAS meta-analysis., Methods: We built gene expression predictive models in blood B cells, CD4 + and CD8 + T cells, monocytes, natural killer cells and peripheral blood cells of 105 Japanese individuals. We performed a transcriptome-wide association study (TWAS) using data from the latest genome-wide association meta-analysis of 208 370 East Asians and searched for candidate genes using TWAS and three data-driven computational approaches., Results: TWAS identified 171 genes for SLE (p<1.0×10 -5 ); 114 (66.7%) showed significance only in a single cell type; 127 (74.3%) were in SLE GWAS loci. TWAS identified a strong association between CD83 and SLE (p<7.7×10 -8 ). Meta-analysis of genetic associations in the existing 208 370 East Asian and additional 1498 cases and 3330 controls found a novel single-variant association at rs72836542 (OR=1.11, p=4.5×10 -9 ) around CD83 . For the 110 SLE loci, we identified 276 gene candidates, including 104 genes at recently-identified SLE novel loci. We demonstrated in vitro that putative causal variant rs61759532 exhibited an allele-specific regulatory effect on ACAP1 , and that presence of the SLE risk allele decreased ACAP1 expression., Conclusions: Cell-level TWAS in six types of immune cells complemented SLE gene discovery and guided the identification of novel genetic associations. The gene findings shed biological insights into SLE genetic associations., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)

Objective: Systemic lupus erythematosus (SLE), an autoimmune disorder, has been associated with nearly 100 susceptibility loci. Nevertheless, these loci only partially explain SLE heritability and their putative causal variants are rarely prioritised, which make challenging to elucidate disease biology. To detect new SLE loci and causal variants, we performed the largest genome-wide meta-analysis for SLE in East Asian populations., Methods: We newly genotyped 10 029 SLE cases and 180 167 controls and subsequently meta-analysed them jointly with 3348 SLE cases and 14 826 controls from published studies in East Asians. We further applied a Bayesian statistical approach to localise the putative causal variants for SLE associations., Results: We identified 113 genetic regions including 46 novel loci at genome-wide significance (p<5×10 -8 ). Conditional analysis detected 233 association signals within these loci, which suggest widespread allelic heterogeneity. We detected genome-wide associations at six new missense variants. Bayesian statistical fine-mapping analysis prioritised the putative causal variants to a small set of variants (95% credible set size ≤10) for 28 association signals. We identified 110 putative causal variants with posterior probabilities ≥0.1 for 57 SLE loci, among which we prioritised 10 most likely putative causal variants (posterior probability ≥0.8). Linkage disequilibrium score regression detected genetic correlations for SLE with albumin/globulin ratio (r g =-0.242) and non-albumin protein (r g =0.238)., Conclusion: This study reiterates the power of large-scale genome-wide meta-analysis for novel genetic discovery. These findings shed light on genetic and biological understandings of SLE., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)