TLR7 variants in human lupus patients
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ABSTRACT:
PROVIDER: EGAS00001005965 | EGA |
REPOSITORIES: EGA
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Project description:While circumstantial evidence supports enhanced TLR7 signaling as a mechanism of human systemic autoimmune disease, we have lacked the proof afforded by lupus-causing TLR7 gene variants. Here we describe human systemic lupus erythematosus (SLE) caused by TLR7 gain-of-function (GoF). We identified a de novo, novel, missense TLR7 Y264H variant in a child with severe lupus. The de novo TLR7 Y264H variant selectively increased sensing of guanosine and was sufficient to cause lupus when introduced in mice (kika mice). We performed RNA-seq of kika and wild type B cells cultured for 20 hours with anti-IgM and found a decreased tendency to apoptosis in kika B cells, including decreased expression of active Caspase 3 and also a small decrease in proliferation. Overall, these results suggest that hypersensitive TLR7 signaling allows the survival of B cells that are binding self-antigen through their surface BCR.
2022-02-10 | GSE196316 | GEO
Project description:Genome-wide alternative splice analysis of RNA from lupus and its severe form lupus nephritis We aimed to explore the genome-wide peripheral blood transcriptome of lupus (SLE) and its severe form lupus nephritis (LN) cases compared to healthy subjects (HC) using high density Affymetrix Human Exon1.0.ST arrays. Analysis revealed 15 splice variants that are differentially expressed between SLE/HC and 99 variants between LN/HC (pâ¤0.05,SI>orâ¤0.5,Benjamin Hochberg-False discovery rate correction). Comparison between LN/SLE revealed 7 variants that are differentially expressed with pâ¤0.05,SI>0.5,Benjamin Hochberg-FDR correction. Pathway analysis of differentially spliced genes revealed 11 significant pathways in SLE and 12 in LN (p<0.05). Analysis of peripheral blood transcriptome revealed signature causative genes that are alternatively spliced, signifying their clinical relevance in the pathophysiology of disease. The extent of differential splicing was found to be higher in LN than in SLE, signifying the need for further in-depth research in the same domain. Present study is the first to reveal the significance of alternative variants in susceptibility to SLE and LN. We analyzed blood from 11 female subjects (5 lupus, 3 lupus nephritis and 3 healthy control) using the Affymetrix Human Exon 1.0 ST platform. Array data was processed by Alt Analyze and Genespring software. No techinical replicates were performed. One of the outiler sample (HC2) was excluded from further analysis.
2016-01-06 | E-GEOD-62764 | biostudies-arrayexpress
Project description:Abstract Introduction Several environmental stimuli may influence lupus, especially viral infection. We utilize an imiquimod-induced lupus mouse model focusing on TLR7 pathway and use proteomics analysis to figure out the specific pathway related to viral infection and its related protein expressions in splenic B cells, hoping to get an insight on B cell responses to viral infection in lupus model. Material and methods. FVB/N wild type mouse was used treated with imiquimod for 8 weeks to induce lupus symptoms and signs, and splenocytes were retrieved, and B cells were selected and conducted proteomic analysis. The B cells were co-cultured with CD40L+ feeder cells for another one week before Western blot analysis. Panther pathway analysis was used to disclose the pathways activated and protein-protein interactome analyzed by STRING database in this lupus murine model. Results. The lupus model is well established and well demonstrated with serology evidence and pathology proof of lupus-mimic organ damage. Proteomics data of splenic B cells revealed the most important pathways activated (fold enrichment >100) were positive regulation of MDA-5 signaling pathway, negative regulation of IP-10 production, negative regulation of chemokine (C-X-C motif) ligand 2 production and positive regulation of RIG-I signaling pathway. A unique protein-protein interactome containing 10 genes was discovered, within which ISG15, IFIH1, IFIT1, DDX60, and DHX58 have been demonstrated to be downstream effectors of MDA5 signaling. Finally, B cells intracellular cytosolic proteins were determined with Western blot experiment and the MDA5-related pathway activation is still evident. Conclusion. In this experiment, we confirmed that the B cells in lupus murine model focusing on TLR7 pathway were activated through MDA5 signaling pathway, an important RNA sensor implicated in the detection of viral infections and autoimmune. The MDA5 agonists/antagonist RNAs and detailed molecular interactions inside B cells are worthy further investigation for lupus therapy.
2023-03-10 | PXD034855 | Pride
Project description:Low capacity to produce reactive oxygen species (ROS) due to mutations in neutrophil cytosolic factor 1 (NCF1/p47phox) is strongly associated with lupus development both in humans and mouse models. Here, we aim to identify the major mechanisms of the Ncf1-disease association. We found that plasmacytoid dendritic cells (pDCs), the most potent producers of type I IFNs, exacerbate pristane-induced lupus in ROS-defective Ncf1-mutant and human NCF1-339 variant carrying mice. ROS deficiency in mouse models with Ncf1 mutation or human NCF1-339 variant leads to enhanced pDC generation via the TLR7/AKT/mTOR pathway and accumulation at sites of inflammation, resulting in an increased IFNα secretion. The produced IFNα further stimulates the JAK1/STAT1 pathway, which we found is hyperreactive in ROS-deficient pDCs. This, in turn, leads to increased type I IFN signature and enhanced proinflammatory responses. Our discoveries explain the causative effect of dysfunctional Ncf1 and pathogenicity of pDCs in lupus.
2023-03-12 | PXD035964 | Pride
Project description:Genome-wide alternative splice analysis of RNA from lupus and its severe form lupus nephritis We aimed to explore the genome-wide peripheral blood transcriptome of lupus (SLE) and its severe form lupus nephritis (LN) cases compared to healthy subjects (HC) using high density Affymetrix Human Exon1.0.ST arrays. Analysis revealed 15 splice variants that are differentially expressed between SLE/HC and 99 variants between LN/HC (p≤0.05,SI>or≤0.5,Benjamin Hochberg-False discovery rate correction). Comparison between LN/SLE revealed 7 variants that are differentially expressed with p≤0.05,SI>0.5,Benjamin Hochberg-FDR correction. Pathway analysis of differentially spliced genes revealed 11 significant pathways in SLE and 12 in LN (p<0.05). Analysis of peripheral blood transcriptome revealed signature causative genes that are alternatively spliced, signifying their clinical relevance in the pathophysiology of disease. The extent of differential splicing was found to be higher in LN than in SLE, signifying the need for further in-depth research in the same domain. Present study is the first to reveal the significance of alternative variants in susceptibility to SLE and LN.
2016-01-06 | GSE62764 | GEO
Project description:To explore the underlying molecular and cellular mechanisms of increased efficacy of the combination therapy regimen, we employed a mouse model of lupus nephritis, MRL/lpr mice, and treated them with monotherapies of prednisone, mycophenolate mofetil, or tacrolimus, or with their combination. Consistent with previous clinical findings, combination therapy markedly improved renal outcome compared to the monotherapies in mice with lupus nephritis. Transcriptomic analysis of their kidneys revealed distinct molecular pathways that were differentially regulated in combination therapy versus monotherapies. Combination therapy not only provided additive immunosuppressive effects, but also induced gene expression and molecular pathways to confer enhanced renoprotection. Specifically, combination therapy inhibited TLR7 expression in the kidneys of mice with lupus nephritis; combination of tacrolimus and mycophenolate mofetil led to better stabilization of the podocyte actin cytoskeleton through the reciprocal regulation of RhoA and Rac1 activities. Combination therapy strongly suppressed the IL-6/Stat3 pathway. These findings were further validated in renal biopsy samples from patients with lupus nephritis before and after treatments with mycophenolate mofetil, tacrolimus or combination therapy. Thus, our study further supports the earlier clinical finding and further provides insights into the molecular basis for increased efficacy of combination therapy.
2020-06-24 | GSE153021 | GEO
Project description:TLR7 gain-of-function genetic variation causes human lupus
| PRJNA804244 | ENA
Project description:Hyperactive TLR7 signaling has long been appreciated as a driver of autoimmune disease in mouse models by breaking tolerance to self-nucleic acids1-5. Recently, the first monogenic mutations within TLR7 or its associated regulator Unc93b16,7 have been identified as causative agents of human lupus. The unifying feature of these mutations is TLR7 gain-of-function resulting from increased ligand binding. TLR7 is an intracellular transmembrane receptor, localized to late endosomes, that senses RNA breakdown products within these hydrolytic compartments8,9. Hence, its function depends on a complex interplay between specialized organelles, transport mechanisms and membrane interactions. Whether perturbations of any of these endosome-related processes can give rise to TLR7 gain-of-function and facilitate self-reactivity has not been investigated. Here we show that a dysregulated endosomal compartment can result in TLR7 gain-of-function and lupus disease in humans. Mechanistically, the late endosomal protein complex BORC-Arl8b controls TLR7 protein levels by mediating the receptor's final sorting step towards lysosomal degradation. A direct interaction between Arl8b and Unc93b1 is required to regulate the turnover of TLR7. We identified an amino acid insertion in Unc93b1 in a patient with childhood-onset lupus, which results in loss of interaction with the BORC-Arl8b complex and an accumulation of functional TLR7. Our results highlight the importance of an intact endomembrane system to prevent autoimmune disease. Disrupting the proper progression of TLR7 through its endocytic life cycle is sufficient to break immunological tolerance to nucleic acids. Our work expands the repertoire of cellular mechanisms important to restrict pathological TLR7 activity. Identifying and stratifying lupus patients based on a TLR7-driven pathology opens the way for precision medicine specifically targeting TLR7.
2023-11-22 | PXD040042 | Pride
Project description:Hyperactive TLR7 signaling has long been appreciated as a driver of autoimmune disease in mouse models by breaking tolerance to self-nucleic acids1-5. Recently, the first monogenic mutations within TLR7 or its associated regulator Unc93b16,7 have been identified as causative agents of human lupus. The unifying feature of these mutations is TLR7 gain-of-function resulting from increased ligand binding. TLR7 is an intracellular transmembrane receptor, localized to late endosomes, that senses RNA breakdown products within these hydrolytic compartments8,9. Hence, its function depends on a complex interplay between specialized organelles, transport mechanisms and membrane interactions. Whether perturbations of any of these endosome-related processes can give rise to TLR7 gain-of-function and facilitate self-reactivity has not been investigated. Here we show that a dysregulated endosomal compartment can result in TLR7 gain-of-function and lupus disease in humans. Mechanistically, the late endosomal protein complex BORC-Arl8b controls TLR7 protein levels by mediating the receptor's final sorting step towards lysosomal degradation. A direct interaction between Arl8b and Unc93b1 is required to regulate the turnover of TLR7. We identified an amino acid insertion in Unc93b1 in a patient with childhood-onset lupus, which results in loss of interaction with the BORC-Arl8b complex and an accumulation of functional TLR7. Our results highlight the importance of an intact endomembrane system to prevent autoimmune disease. Disrupting the proper progression of TLR7 through its endocytic life cycle is sufficient to break immunological tolerance to nucleic acids. Our work expands the repertoire of cellular mechanisms important to restrict pathological TLR7 activity. Identifying and stratifying lupus patients based on a TLR7-driven pathology opens the way for precision medicine specifically targeting TLR7.
2023-11-22 | PXD039263 | Pride