Nao Tanaka

We conducted the largest-ever cross-ancestry GWAS meta-analysis for SLE with 25,109 cases and 271,084 controls comprising East Asian (EA), Southeast Asians (SEA) and Europeans (EUR). We identified 279 independent non-MHC associations, including 51 unreported SLE associations, among which EA-driven associations were identified at PIK3AP1, FOXK1, UBASH3A, and CTDSP1. We further identified a significant interactive association between FOXK1 and IRF5 variants. Statistical fine-mapping together with SNP-to-gene inference and functional prediction identified plausible causal non-coding variants in PRKD3 and TSPAN32, as well as variants in enhancers for CD83, IL12A, c-MYC, and l-MYC, along with an EA-specific missense variant rs55882956 in TYK2. Transcription factors (TFs) linked to fine-mapped enhancer variants contributed to trans-acting regulatory mechanisms in SLE, with strong heritability enrichment at their binding sites across various immune cell types. These include a disproportionate representation of B cell TFs that are themselves risk genes. MYC protein showed the largest enrichment at its binding sites in B cells. In addition, Prioritizing MYC binding sites of B cells in polygenic risk score improved SLE prediction. We also identified 67 candidate druggable genes, providing mechanistic insights and highlighting opportunities for therapeutic development in SLE.

Transcribed enhancer maps can reveal nuclear interactions underpinning each cell type and connect specific cell types to diseases. Using a 5′ single-cell RNA sequencing approach, we defined transcription start sites of enhancer RNAs and other classes of coding and noncoding RNAs in human CD4 ⁺ T cells, revealing cellular heterogeneity and differentiation trajectories. Integration of these datasets with single-cell chromatin profiles showed that active enhancers with bidirectional RNA transcription are highly cell type–specific and that disease heritability is strongly enriched in these enhancers. The resulting cell type–resolved multimodal atlas of bidirectionally transcribed enhancers, which we linked with promoters using fine-scale chromatin contact maps, enabled us to systematically interpret genetic variants associated with a range of immune-mediated diseases.

Here we report the largest Asian genome-wide association study (GWAS) for systemic sclerosis performed to date, based on data from Japanese subjects and comprising of 1428 cases and 112,599 controls. The lead SNP is in the FCGR/FCRL region, which shows a penetrating association in the Asian population, while a complete linkage disequilibrium SNP, rs10917688, is found in a cis-regulatory element for IRF8. IRF8 is also a significant locus in European GWAS for systemic sclerosis, but rs10917688 only shows an association in the presence of the risk allele of IRF8 in the Japanese population. Further analysis shows that rs10917688 is marked with H3K4me1 in primary B cells. A meta-analysis with a European GWAS detects 30 additional significant loci. Polygenic risk scores constructed with the effect sizes of the meta-analysis suggest the potential portability of genetic associations beyond populations. Prioritizing the top 5% of SNPs of IRF8 binding sites in B cells improves the fitting of the polygenic risk scores, underscoring the roles of B cells and IRF8 in the development of systemic sclerosis. The results also suggest that systemic sclerosis shares a common genetic architecture across populations.

Atopic dermatitis (AD) is a common inflammatory skin condition and prior genome-wide association studies (GWAS) have identified 71 associated loci. In the current study we conducted the largest AD GWAS to date (discovery N = 1,086,394, replication N = 3,604,027), combining previously reported cohorts with additional available data. We identified 81 loci (29 novel) in the European-only analysis (which all replicated in a separate European analysis) and 10 additional loci in the multi-ancestry analysis (3 novel). Eight variants from the multi-ancestry analysis replicated in at least one of the populations tested (European, Latino or African), while two may be specific to individuals of Japanese ancestry. AD loci showed enrichment for DNAse I hypersensitivity and eQTL associations in blood. At each locus we prioritised candidate genes by integrating multi-omic data. The implicated genes are predominantly in immune pathways of relevance to atopic inflammation and some offer drug repurposing opportunities.

We conducted a Japanese GWAS for systemic sclerosis (SSc) comprising 1,428 cases and 112,599 controls, the largest Asian GWAS for SSc ever, and identified three novel signals. The lead SNP in FCGR/FCRL region had a strong effect size (OR 2.05, P = 4.9×10⁻¹¹). The complete LD SNP, rs10917688, was found in a cis-regulatory element and a part of binding motifs for IRF8. IRF8 was a significant locus in the European GWAS and rs10917688 showed an association only in the presence of the risk allele of IRF8 in Japanese. rs10917688 was marked with H3K4me1 in primary B cells, and the heritability was enriched in active histone marks of primary B cells. A meta-analysis with the latest European GWAS found additional 30 significant loci including three novel signals. PRS constructed with the effect sizes of the meta-analysis indicated potential portability of genetic associations beyond populations (AUC: 0.593). The fitting of PRS was improved by further prioritizing the top 5% SNPs of IRF8 biding sites in B cells, underscoring common genetic architecture across populations and critical roles of B cells and IRF8 for SSc development.