Project description:Local catabolism of the amino acid tryptophan (Trp) by indoleamine-2,3-dioxygenase (IDO) is considered an important mechanism of regulating T cell immunity. We show that IDO transcription was increased upon stimulation of myelin-specific T cells with tolerogenic altered self-peptides. Catabolites of Trp suppressed proliferation of myelin-specific T cells and inhibited production of proinflammatory TH1 cytokines. N-(3,4,-dimethoxycinnamoyl) anthranilic acid (3,4-DAA), an orally active synthetic derivative of the Trp metabolite anthranilic acid, reversed paralysis in mice with experimental autoimmune encephalomyelitis, a model of multiple sclerosis (MS). Trp catabolites and their derivatives offer a new strategy for treating TH1-mediated autoimmune diseases, such as MS. 4Y vd 1-11 comparison files are available as supplementary files. Keywords: 48hr activation, MBPAc1-11 Cd4+ T cell, murine Mu11ksubA and Mu11subB combined anaylsis
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.
Project description:Type I interferon (IFN-I) is essential in the development of Systemic Lupus Erythematosus (SLE) and many other autoimmune diseases. To explore the metabolic regulations of IFN-I signaling pathway, we conducted a high through-put screening of a small molecule library and identified diosmetin as a potent compound for blocking IFN-I signaling. Diosmetin can ameliorate lupus-like autoimmune phenotypes in IFNα-accelerated NZB/NZW F1 lupus model and pristane-induced murine lupus model. Of note, diosmetin can block over-activated IFN-I signaling pathway in PBMCs from lupus patients by reducing the expression of CYP1B1. Our findings reveal a novel lipid metabolic regulation of IFN-I signaling and a potent alternative therapeutic target for autoimmune diseases with overactivated IFN-I signaling pathway.
Project description:Type I interferon (IFN-I) is essential in the development of Systemic Lupus Erythematosus (SLE) and many other autoimmune diseases. To explore the metabolic regulations of IFN-I signaling pathway, we conducted a high through-put screening of a small molecule library and identified diosmetin as a potent compound for blocking IFN-I signaling. Diosmetin can ameliorate lupus-like autoimmune phenotypes in IFNα-accelerated NZB/NZW F1 lupus model and pristane-induced murine lupus model. Of note, diosmetin can block over-activated IFN-I signaling pathway in PBMCs from lupus patients by reducing the expression of CYP1B1. Our findings reveal a novel lipid metabolic regulation of IFN-I signaling and a potent alternative therapeutic target for autoimmune diseases with overactivated IFN-I signaling pathway.
Project description:Local catabolism of the amino acid tryptophan (Trp) by indoleamine-2,3-dioxygenase (IDO) is considered an important mechanism of regulating T cell immunity. We show that IDO transcription was increased upon stimulation of myelin-specific T cells with tolerogenic altered self-peptides. Catabolites of Trp suppressed proliferation of myelin-specific T cells and inhibited production of proinflammatory TH1 cytokines. N-(3,4,-dimethoxycinnamoyl) anthranilic acid (3,4-DAA), an orally active synthetic derivative of the Trp metabolite anthranilic acid, reversed paralysis in mice with experimental autoimmune encephalomyelitis, a model of multiple sclerosis (MS). Trp catabolites and their derivatives offer a new strategy for treating TH1-mediated autoimmune diseases, such as MS. 4Y vd 1-11 comparison files are available as supplementary files. Experiment Overall Design: Double stranded cDNA was generated from total RNA extracted from MBP Ac 11-11 activated purified CD4+ T cells. Biotinylated cRNA was manufactured by in vitro transcription and hybridized to the Affymetrix genechip murine Mu11k set according to the manufacturer's protocols. Results were calculated as the ratio of mean average differences for each gene in 4Y versus Ac1-11 stimulated samples.
Project description:Altered tryptophan catabolism has been identified in inflammatory diseases like rheumatoid arthritis (RA) and spondyloarthritis (SpA), but the causal mechanisms linking tryptophan metabolites to disease are unknown. Using the collagen-induced arthritis (CIA) model we identify alterations in tryptophan metabolism, and specifically indole, that correlate with disease. We demonstrate that both bacteria and dietary tryptophan are required for disease, and indole supplementation is sufficient to induce disease in their absence. When mice with CIA on a low-tryptophan diet were supplemented with indole, we observed significant increases in serum IL-6, TNF, and IL-1β; splenic RORγt+CD4+ T cells and ex vivo collagen-stimulated IL-17 production; and a pattern of anti-collagen antibody isotype switching and glycosylation that corresponded with increased complement fixation. IL-23 neutralization reduced disease severity in indole-induced CIA. Finally, exposure of human colon lymphocytes to indole increased expression of genes involved in IL-17 signaling and plasma cell activation. Altogether, we propose a mechanism by which intestinal dysbiosis during inflammatory arthritis results in altered tryptophan catabolism, leading to indole stimulation of arthritis development. Blockade of indole generation may present a novel therapeutic pathway for RA and SpA.
Project description:Tryptophan metabolism and de novo NAD biosynthesis is associated with behavioural changes in IBD patients. The microbiota and tryptophan de novo syntheses of the distal colon, distal colon and brain of C57BL/6 control mice and Winnie mice littermates with chronic intestinal inflammation were compared using RNA-Seq. Differentially expressed genes were analysed using Micromon software. Changes in tryptophan and nicotinamide metabolism-associated gene expressions, metabolites, and abundance of gut microbiota associated with chronic intestinal inflammation and dysregulated tryptophan metabolism in the Winnie mouse distal colon and brain were apparent. Our findings shed light on the physiological alterations in tryptophan metabolism, specifically its diversion from the serotonergic pathway towards the kynurenine pathway and the consequential effects on de novo NAD+ synthesis, in the context of chronic intestinal inflammation
Project description:We previously showed that all-trans-retinoic acid (tRA), an active metabolite of vitamin A, exacerbated pre-existing autoimmunity in lupus; however, its effects before the development of autoimmunity are unknown. Here, using a pristane-induced model, we show that tRA exerts differential effects when given at the initiation vs. continuation phase of lupus. Unlike tRA treatment during active disease, pre-pristane treatment with tRA aggravated glomerulonephritis through increasing renal expression of pro-fibrotic protein laminin β1, activating bone marrow conventional dendritic cells (cDCs), and upregulating the interaction of ICAM-1 and LFA-1 in the spleen indicating an active process of leukocyte activation and trafficking. Transcriptomic analysis revealed that prior to lupus induction, tRA significantly upregulated the expression of genes associated with cDC activation and migration. Post-pristane tRA treatment, on the other hand, did not significantly alter the severity of glomerulonephritis; rather, it exerted immunosuppressive functions of decreasing circulatory and renal deposition of autoantibodies as well as suppressing the renal expression of proinflammatory cytokines and chemokines. Together, these findings suggest that tRA differentially modulate lupus-associated kidney inflammation depending on the time of administration. Interestingly, both pre- and post-pristane treatments with tRA reversed pristane-induced leaky gut and modulated the gut microbiota in a similar fashion, suggesting a gut microbiota-independent mechanism by which tRA affects the initiation vs. continuation phase of lupus.
Project description:In the experimental autoimmune encephalomyelitis (EAE) model we found that omission of the essential amino acid tryptophan (trp) abrogates central nervous system (CNS) autoimmunity. Impaired encephalitogenic T responses were accompanied by an inflammatory response in the colonic mucosa, as well as a profound shift in the gut microbiota. Here, we performed transcriptional profiling of colon tissue by RNA-sequencing 14 days after disease induction in mice that received a trp-free diet or a matched control group to identify key networks that drive this immunosuppressive effect.