Project description:Enhancers affect gene expression and disease. Little is known about enhancers that regulate human disease-associated genes in their native chromosomal context in primary cells relevant for pathogenesis. We used a BAC transgenic approach combined with CRISPR- and recombineering-mediated genome editing to dissect enhancers that regulate human TNFAIP3/A20, which is tightly linked with autoimmune diseases, in vivo and in primary immune cells. >20 enhancers in the A20 superenhancer were redundant; A20 expression was regulated by a topologically associating subdomain (sub-TAD) that harbors 5 enhancers. Deletion of this sub- TAD enhanced inflammatory responses and autoantibody production, establishing its functional importance in vivo. We identified cell- and activation-specific enhancers within this sub-TAD, including a key role for an enhancer harboring a proposed causal SLE-associated SNV. These findings map genomic regions that regulate human A20 expression to prevent inflammatory pathology and autoimmunity, and provide a platform for causally linking enhancers and SNVs with disease phenotypes.
Project description:Enhancers regulate gene expression and have been linked with disease pathogenesis. Little is known about enhancers that regulate human disease-associated genes in primary cells relevant for pathogenesis. Here we use BAC transgenics and genome editing to dissect, in vivo and in primary immune cells, enhancers that regulate human TNFAIP3, which encodes A20 and is linked with autoimmune diseases. A20 expression is dependent on a topologically associating subdomain (sub-TAD) that harbors four enhancers, while another >20 enhancers in the A20 locus are redundant. This sub-TAD contains cell- and activation-specific enhancers, including an enhancer (termed TT>A) harboring a proposed causal SLE-associated SNV. Deletion of the sub-TAD or the TT>A enhancer results in enhanced inflammatory responses, autoantibody production, and inflammatory arthritis, thus establishing functional importance in vivo and linking enhancers with a specific disease phenotype. These findings provide insights into enhancers that regulate human A20 expression to prevent inflammatory pathology and autoimmunity.
Project description:Early-onset complex autoimmunity can arise from monogenic activating mutations in inflammatory signalling pathways or loss of function mutations of immunoregulatory molecules. We sought to define the molecular basis of severe early-onset autoimmunity, characterised by autoimmune diabetes, cytopenias, hepatitis, enteropathy and interstitial lung disease, in a child without pathogenic variants in STAT3 and FOXP3. We employed whole exome sequencing, together with in vitro assays of tumor necrosis factor-alpha (TNF-α) signalling and response, including RNA sequencing, in patient fibroblasts. We identified a novel de novo heterozygous variant in TNFAIP3, which encodes A20 - a key negative regulator of the NF-κB transcriptional induction pathway. The p.V489Afs*7 variant reduced A20 protein expression and resulted in hyperresponsiveness of TNF-α signal transduction. This was accompanied by significant enhancement of TNF-α induced NF-κB target gene expression. There was an excellent clinical response to matched unrelated haematopoietic stem cell transplantation (HSCT), with resolution of all pathological features except diabetes. This case reveals a novel association between a previously unreported heterozygous TNFAIP3 mutation and the development of early-onset complex autoimmunity, validating existing evidence from both genome-wide association studies and conditional murine knockout models that implicates TNFAIP3 in autoimmune pathogenesis. This case also expands the clinical spectrum of germline A20 haploinsufficiency, recently identified in a cohort of patients with Behçet’s-like autoinflammatory disease, and shows that correction of the molecular defect within the haematopoietic cell compartment may be a viable treatment option for severe clinical manifestations.
Project description:Genetic TNFAIP3 (A20) inactivation is a classical somatic lymphoma lesion and the genomic trait in haploinsufficiency of A20 (HA20). In a cohort of 33 HA20 patients, we show that heterozygous TNFAIP3 loss skews immune repertoires towards lymphocytes with classical self-reactive antigen receptors typically found in B and T cell lymphomas.
Project description:Genetic TNFAIP3 (A20) inactivation is a classical somatic lymphoma lesion and the genomic trait in haploinsufficiency of A20 (HA20). Single-cell sequencing reveals “pre-lymphoma” transcription signatures in lymphocytes of HA20 patients.
Project description:Unique and shared cytogenetic abnormalities have been documented for marginal zone lymphomas (MZLs) arising at different sites. Recently, homozygous deletions of the chromosomal band 6q23, involving the tumor necrosis factor alpha-induced protein 3 (TNFAIP3, A20) gene, a negative regulator of NF-kappa B, were described in ocular adnexal MZL, suggesting a role for A20 as a tumor suppressor in this disease entity. Here, we investigated inactivation of A20 by DNA mutations or deletions in a panel of extranodal (EMZL), nodal (NMZL) and splenic (SMZL) MZLs. Inactivating mutations encoding truncated A20 proteins were identified in 6/32 (18.8%) MZLs, including 3/11 (27.3%) EMZLs, 2/9 (22.2%) NMZLs, and 1/12 (8.3%) SMZLs. Two additional unmutated non-splenic MZLs also showed mono- or biallelic A20 deletions by FISH and/or array-CGH. Thus, A20 loss by both somatic mutations and/or deletions represents a common genetic aberration across all MZL subtypes, which may contribute to lymphomagenesis by inducing constitutive NF-kappa B activation. Keywords: Genome variation profiling by SNP array 27 MZL samples. No technical replications.
Project description:To investigate the impact of A20 on testosterone synthesis in the context of age-related inflammation, we employed lentiviral constructs to establish TNFAIP3-overexpressing TM3 cell lines. Subsequently, we conducted gene expression profiling analysis using RNA-seq data obtained from both normal TM3 cells and TNFAIP3-overexpressing TM3 cells.
Project description:Unique and shared cytogenetic abnormalities have been documented for marginal zone lymphomas (MZLs) arising at different sites. Recently, homozygous deletions of the chromosomal band 6q23, involving the tumor necrosis factor alpha-induced protein 3 (TNFAIP3, A20) gene, a negative regulator of NF-kappa B, were described in ocular adnexal MZL, suggesting a role for A20 as a tumor suppressor in this disease entity. Here, we investigated inactivation of A20 by DNA mutations or deletions in a panel of extranodal (EMZL), nodal (NMZL) and splenic (SMZL) MZLs. Inactivating mutations encoding truncated A20 proteins were identified in 6/32 (18.8%) MZLs, including 3/11 (27.3%) EMZLs, 2/9 (22.2%) NMZLs, and 1/12 (8.3%) SMZLs. Two additional unmutated non-splenic MZLs also showed mono- or biallelic A20 deletions by FISH and/or array-CGH. Thus, A20 loss by both somatic mutations and/or deletions represents a common genetic aberration across all MZL subtypes, which may contribute to lymphomagenesis by inducing constitutive NF-kappa B activation. Keywords: Genome variation profiling by SNP array
Project description:Objectives: Genetic variations in TNFAIP3 (A20) de-ubiquitinase (DUB) domain increase the risk of systemic lupus erythematosus (SLE) and rheumatoid arthritis. A20 is a negative regulator of NF-κB but the role of its DUB domain and related genetic variants remain unclear. We aimed to study the functional effects of A20 DUB-domain alterations in immune cells and understand its link to SLE pathogenesis. Methods: CRISPR/Cas9 was used to generate human U937 monocytes with A20 DUB-inactivating C103A knock-in mutation. Whole genome RNA-sequencing was used to identify differentially expressed genes between WT and C103A knock-in cells. Functional studies were performed in A20 C103A U937 cells and in immune cells from A20 C103A mice and genotyped healthy individuals with A20 DUB polymorphism rs2230926. Neutrophil extracellular trap (NET) formation was adressed ex vivo in neutrophils from A20 C103A mice and SLE-patients with rs2230926. Results: Genetic disruption of A20 DUB domain in human and murine myeoloid cells did not give rise to enhanced NF-κB signaling. Instead, cells with C103A mutation or rs2230926 polymorphism presented an upregulated expression of PADI4, an enzyme regulating protein citrullination and NET formation, two key mechanisms in autoimmune pathology. A20 C103A cells exhibited enhanced protein citrullination and extracellular trap formation, which could be suppressed by selective PAD4 inhibition. Moreover, SLE-patients with rs2230926 showed increased NETs and increased frequency of autoantibodies to citrullinated epitopes. Conclusions: We propose that genetic alterations disrupting the A20 DUB domain mediate increased susceptibility to SLE through the upregulation of PADI4 with resultant protein citrullination and extracellular trap formation.
Project description:In addition to autoimmune and inflammatory diseases, variants of the TNFAIP3 gene encoding A20 are also associated with systemic sclerosis (SSc). However, it remains unclear how genetic factors contribute to fibrosis in SSc, and which cell types drive disease due to SSc-specific genetic alterations. We characterized the expression and function of A20, and its negative transcriptional regulator DREAM, in patient with SSc. We found that levels of A20 were significantly reduced in SSc skin and lung biopsies, while DREAM was elevated and showed anti-correlation with A20. Mice haploinsufficient for A20, or harboring fibroblasts-specific A20 deletion, recapitulated major pathological and genomic features of SSc, whereas DREAM-null mice showed elevated A20 expression and were protected from fibrosis. In fibroblasts, A20 mitigated ex vivo profibrotic responses. An anti-fibrotic small molecule targeting the adiponectin receptors stimulated A20 expression in vitro in wildtype but not A20-deficient fibroblasts, and in bleomycin-treated mice. Thus, A20 has a novel function in negative regulation of fibroblast responses, and together with DREAM, constitutes a critical regulatory network governing the fibrotic process in SSc, suggesting that A20 and DREAM represent novel druggable targets.