Date: Monday, October 22, 2018
Session Type: ACR Concurrent Abstract Session
Session Time: 2:30PM-4:00PM
Loss of function RUNX3 variants are associated with ankylosing spondylitis (AS) risk but the mechanism is unknown. Disturbances in immune regulation, intestinal microbial dysbiosis and subclinical intestinal inflammation characterize AS, and flares in intestinal inflammation are associated with arthritis severity. Intestinal regulatory T cells (Foxp3+ Treg) limit inflammation, and TCRαβ+CD4+CD8+ cytotoxic T cells (CD4CTL) control intracellular bacteria at epithelial interfaces. CD4CTL develop in response to antigen presented by retinoic acid (RA)-producing dendritic cells. TGF-β and RA enhance CD4+ T cell Runx3 and suppress ThPOK for CD4CTL trans-differentiation. ZAP70W163C mutant (SKG) mice have reduced ZAP70 signaling, spondyloarthritis and ileitis. We investigated ZAP70 in Runx3 signaling and CD4CTL development.
We isolated ileal intraepithelial and lamina propria lymphocytes and analysed Treg and CD4CTL. CD4CTL were generated in vitro by culture of OVA-specific DO11.10 and SKG.DO11.10 T cells with OVA peptide, TGF-b and RA, and in vivo by transfer of OVA-specific T cells to immune-deficient mice fed OVA. Differentially-expressed genes from terminal ileum of 8 naïve SKG and 3 BALB/c mice were assessed by RNA microarray (Illumina). We compared enrichment of Runx3-regulated genes uncovered by ChIP-seq and transcriptome analysis in SKG and BALB/c mice. T cells isolated from human colon, ileum and blood of 5 AS patients and 5 healthy controls (HC) were analyzed.
CD4CTL and Runx3 expression were reduced, while Foxp3+ pTreg were increased SKG relative to BALB/c ileum. Tissue resident memory T cell-associated genes e.g. Cd3e, Itgae, Ccl5, and Itgb7, and antigen processing and presentation genes e.g. H2-ab1, H2-Dma, H2-ea, Tap1, and H2-q8, were downregulated in SKG relative to BALB/c ileum. 36% of differentially-expressed genes are Runx3-regulated genes, previously identified by ChIP-Seq. The SKG ZAP70-mediated TCR loss of function prevented effective intestinal CD4CTL but not pTreg differentiation in context of TGF-β and RA in vitro and in vivo, resulting in Runx3 and ThPOK dysregulation. CD4CTL and their expression of perforin, IFN-g, NFAT and Runx3 were decreased in intestine and blood of AS patients compared with HC.
High-affinity TCR-ZAP70 signaling is required for RUNX3-mediated intestinal CD4CTL differentiation and the balance with Foxp3+ Treg. Runx3 deficiency links intestinal pathology in mice and humans through CD4CTL. Since deficiency of CD4CTL cells with cytotoxic function should limit host control of intracellular pathobiont species, reduced TCR-ZAP70-RUNX3 is a key pathogenetic pathway in spondyloarthropathy.
To cite this abstract in AMA style:Bhuyan ZA, Rahman MA, Maradana M, Mehdi A, Guggino G, Leo P, Rehaume L, Brown M, Ciccia F, Thomas R. Intestinal Inflammatory Regulation in Murine and Human Spondyloarthropathy Requires High-Affinity T Cell Receptor-Zeta Chain-Associated Protein (ZAP)70-Mediated Runt-Related Transcription Factor (Runx)3 Activity [abstract]. Arthritis Rheumatol. 2018; 70 (suppl 10). https://acrabstracts.org/abstract/intestinal-inflammatory-regulation-in-murine-and-human-spondyloarthropathy-requires-high-affinity-t-cell-receptor-zeta-chain-associated-protein-zap70-mediated-runt-related-transcription-factor-runx/. Accessed November 18, 2019.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/intestinal-inflammatory-regulation-in-murine-and-human-spondyloarthropathy-requires-high-affinity-t-cell-receptor-zeta-chain-associated-protein-zap70-mediated-runt-related-transcription-factor-runx/