Dataset Information

Altered cytokine expression by macrophages from HLA-B27-positive spondyloarthritis patients without evidence of endoplasmic reticulum stress.

ABSTRACT:

Objectives

We investigated endoplasmic reticulum (ER) stress and cytokine expression in peripheral blood-derived macrophages and synovial tissue from HLA-B27⁺ SpA patients.

Methods

Macrophages from healthy donors, SpA and RA patients were polarized with IFN-γ or IL-10 and activated with lipopolysaccharide. Expression of ER stress markers (BiP, CHOP, ERdj4) and cytokines (IL-23, IL-12, TNF, IL-10) was measured by qRT-PCR. Expression of ER stress markers and cytokines in synovial tissue from SpA patients was evaluated by microarray analysis.

Results

Macrophages from HLA-B27⁺ SpA patients did not show elevated ER stress markers. However, the expression of IL-23 and IL-12 by peripheral blood-derived macrophages was higher in HLA-B27⁺ SpA in comparison with healthy donors. Synovial tissue from HLA-B27⁺ SpA patients showed higher expression of TNF compared with HLA-B27^- SpA patients.

Conclusion

HLA-B27⁺ SpA patients showed increased expression of IL-23, IL-12 and TNF without evidence of ER stress.

SUBMITTER: Ambarus CA

PROVIDER: S-EPMC6649909 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Publications

Altered cytokine expression by macrophages from HLA-B27-positive spondyloarthritis patients without evidence of endoplasmic reticulum stress.

Ambarus Carmen A CA Yeremenko Nataliya N Baeten Dominique L DL

Rheumatology advances in practice 20180427 1

<h4>Objectives</h4>We investigated endoplasmic reticulum (ER) stress and cytokine expression in peripheral blood-derived macrophages and synovial tissue from HLA-B27<sup>+</sup> SpA patients.<h4>Methods</h4>Macrophages from healthy donors, SpA and RA patients were polarized with IFN-γ or IL-10 and activated with lipopolysaccharide. Expression of ER stress markers (BiP, CHOP, ERdj4) and cytokines (IL-23, IL-12, TNF, IL-10) was measured by qRT-PCR. Expression of ER stress markers and cytokines in ...[more]

PMID: 31431962

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Project description:ObjectiveWe undertook this study to examine the functional basis for epistasis between endoplasmic reticulum aminopeptidase 1 (ERAP1) and HLA-B27 in experimental spondyloarthritis (SpA).MethodsERAP1-knockout rats were created using genome editing and bred with HLA-B27/human β2 -microglobulin-transgenic (HLA-B27-Tg) rats and HLA-B7-Tg rats. The effects of ERAP1 deficiency on HLA allotypes were determined using immunoprecipitation and immunoblotting, flow cytometry, allogeneic T cell proliferation assays, and gene expression analyses. Animals were examined for clinical features of disease, and tissue was assessed by histology.ResultsERAP1 deficiency increased the ratio of folded to unfolded (β2 m-free) HLA-B27 heavy chains, while having the opposite effect on HLA-B7. Furthermore, in rats with ERAP1 deficiency, HLA-B27 misfolding was reduced, while free HLA-B27 heavy chain dimers on the cell surface and monomers were increased. The effects of ERAP1 deficiency persisted during up-regulation of HLA-B27 and led to a reduction in endoplasmic reticulum stress. ERAP1 deficiency reduced the prevalence of arthritis in HLA-B27-Tg rats by two-thirds without reducing gastrointestinal inflammation. Dendritic cell abnormalities attributed to the presence of HLA-B27, including reduced allogeneic T cell stimulation and loss of CD103-positive/major histocompatibility complex class II-positive cells, were not rescued by ERAP1 deficiency, while excess Il23a up-regulation was mitigated.ConclusionERAP1 deficiency reduced HLA-B27 misfolding and improved folding while having opposing effects on HLA-B7. The finding that HLA-B27-Tg rats had partial protection against SpA in this study is consistent with genetic evidence that loss-of-function and/or reduced expression of ERAP1 reduces the risk of ankylosing spondylitis. Functional studies support the concept that the effects of ERAP1 on HLA-B27 and SpA may be a consequence of how peptides affect the biology of this allotype rather than their role as antigenic determinants.

Project description:BackgroundAssociation of HLA-B27 with spondyloarthritis (SpA) has been known for 50 years, but still remains unexplained. We recently showed that HLA-B27 expressed in wing imaginal disc from HLA-B27/human-β2 microglobulin (hβ2m) transgenic Drosophila deregulated bone morphogenetic protein (BMP) pathway by interacting physically with type I BMP receptor (BMPR1) Saxophone (Sax), leading to crossveinless phenotype.MethodsGenetic interaction was studied between activin/transforming growth factor β (TGFβ) pathway and HLA-B27/hβ2m in transgenic Drosophila wings. The HLA-B27-bound peptidome was characterized in wing imaginal discs. In mesenteric lymph node (mLN) T cells from HLA-B27/hβ2m rat (B27 rat), physical interaction between HLA-B27 and activin receptor-like kinase-2 (ALK2), ALK3 and ALK5 BMPR1s, phosphorylation of small mothers against decapentaplegic (SMADs) and proteins of the non-canonical BMP/TGFβ pathways induced by its ligands, and the transcript level of target genes of the TGFβ pathway, were evaluated.ResultsIn HLA-B27/hβ2m transgenic Drosophila, inappropriate signalling through the activin/TGFβ pathway, involving Baboon (Babo), the type I activin/TGFβ receptor, contributed to the crossveinless phenotype, in addition to deregulated BMP pathway. We identified peptides bound to HLA-B27 with the canonical binding motif in HLA-B27/hβ2m transgenic Drosophila wing imaginal disc. We demonstrated specific physical interaction, between HLA-B27/hβ2m and mammalian orthologs of Sax and Babo, i.e. ALK2 and ALK5 (i.e. TGFβ receptor I), in the mLN cells from B27 rat. The magnitude of phosphorylation of SMAD2/3 in response to TGFβ1 was increased in T cells from B27 rats, showing evidence for deregulated TGFβ pathway. Accordingly, expression of several target genes of the pathway was increased in T cells from B27 rats, in basal conditions and/or after TGFβ exposure, including Foxp3, Rorc, Runx1 and Maf. Interestingly, Tgfb1 expression was reduced in naive T cells from B27 rats, even premorbid, an observation consistent with a pro-inflammatory pattern.ConclusionsThis study shows that HLA-B27 alters the TGFβ pathways in Drosophila and B27 rat. Given the importance of this pathway in CD4 + T cells differentiation and regulation, its disturbance could contribute to the abnormal expansion of pro-inflammatory T helper 17 cells and altered regulatory T cell phenotype observed in B27 rats.

Project description:ObjectiveHLA-B27-associated spondyloarthritides are associated with an altered intestinal microbiota and bowel inflammation. We undertook this study to identify HLA-B27-dependent changes in both host and microbial metabolites in the HLA-B27/β2 -microglobulin (β2 m)-transgenic rat and to determine whether microbiota-derived metabolites could impact disease in this major model of spondyloarthritis.MethodsCecal contents were collected from Fischer 344 33-3 HLA-B27/β2 m-transgenic rats and wild-type controls at 6 weeks (before disease) and 16 weeks (with active bowel inflammation). Metabolomic profiling was performed by high-throughput gas and liquid chromatography-based mass spectrometry. HLA-B27/β2 m-transgenic rats were treated with the microbial metabolites propionate or butyrate in drinking water for 10 weeks, and disease activity was subsequently assessed.ResultsOur screen identified 582 metabolites, of which more than half were significantly altered by HLA-B27 expression at 16 weeks. Both microbial and host metabolites were altered, with multiple pathways affected, including those for amino acid, carbohydrate, xenobiotic, and medium-chain fatty acid metabolism. Differences were even observed at 6 weeks, with up-regulation of histidine, tyrosine, spermidine, N-acetylmuramate, and glycerate in HLA-B27/β2 m-transgenic rats. Administration of the short-chain fatty acid propionate significantly attenuated HLA-B27-associated inflammatory disease, although this was not associated with increased FoxP3+ T cell induction or with altered expression of the immunomodulatory cytokines interleukin-10 (IL-10) or IL-33 or of the tight junction protein zonula occludens 1. HLA-B27 expression was also associated with altered host expression of messenger RNA for the microbial metabolite receptors free fatty acid receptor 2 (FFAR2), FFAR3, and niacin receptor 1.ConclusionHLA-B27 expression profoundly impacts the intestinal metabolome, with changes evident in rats even at age 6 weeks. Critically, we demonstrate that a microbial metabolite, propionate, attenuates development of HLA-B27-associated inflammatory disease. These and other microbiota-derived bioactive mediators may provide novel treatment modalities in HLA-B27-associated spondyloarthritides.

Dataset Information

Altered cytokine expression by macrophages from HLA-B27-positive spondyloarthritis patients without evidence of endoplasmic reticulum stress.

Objectives

Methods

Results

Conclusion

Publications

Altered cytokine expression by macrophages from HLA-B27-positive spondyloarthritis patients without evidence of endoplasmic reticulum stress.

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