Dendritic cells and regulatory T cells in spondyloarthritis

Comparison of immune cells and diagnostic markers between spondyloarthritis and rheumatoid arthritis by bioinformatics analysis

Background

Spondyloarthritis (SpA) and rheumatoid arthritis (RA) are chronic autoimmune diseases, but they are usually difficult to distinguish in the early stage of the diseases. The purpose of this study is to explore the differences of immune mechanism and diagnostic markers through bioinformatics analysis.

Methods

First, microarray datasets from patients with SpA, RA and normal controls were obtained from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) between groups were identified in R software. Functional and pathway enrichment of DEGs were analyzed by David database. Then, we screened the hub genes using Cytoscape plugin, and constructed the protein–protein interaction (PPI) network and heatmap of hub genes. After that, CIBERSORT was used to evaluate the differences and connections of immune cells in SpA and RA, and screened out diagnostic markers. Correlation analysis was used to analyze the relationship between immune cells and diagnostic markers. Finally, quantitative real-time polymerase chain reaction (qRT‐PCR) was used to verify the effectiveness of immunodiagnostic markers.

Results

We obtained three datasets, from which we can see that the functional enrichment of DEGs is mainly in cell chemotaxis, lymphocyte activation, primary immunodeficiency and other immune responses. The difference of immune cells between SpA, RA and normal control was concentrated in B, T lymphocytes cells, macrophages and dendritic cells. C19orf12 + S1PR3 is most associated with these immune cells and S1PR3 can be used as a diagnostic marker of this kind of immune diseases. In addition, MZB1 + XIST is closely related to T cells, NK cells and dendritic cells, and is expected to be used as a marker to distinguish the two diseases.

Conclusion

Although the clinical manifestations of SpA and RA are similar, the pathogenesis is different. The screening of immune cells and diagnostic markers provides a more accurate target for the treatment of this kind of diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03390-y.

Immunopathophysiology of Juvenile Spondyloarthritis (jSpA): The "Out of the Box" View on Epigenetics, Neuroendocrine Pathways and Role of the Macrophage Migration Inhibitory Factor (MIF)

Juvenile spondyloarthritis (jSpA) is a an umbrella term for heterogeneous group of related seronegative inflammatory disorders sharing common symptoms. Although it mainly affects children and adolescents, it often remains active during adulthood. Genetic and environmental factors are involved in its occurrence, although the exact underlying immunopathophysiology remains incompletely elucidated. Accumulated evidence suggests that, in affected patients, subclinical gut inflammation caused by intestinal dysbiosis, is pivotal to the future development of synovial-entheseal complex inflammation. While the predominant role of IL17/23 axis, TNF-α, and IL-7 in the pathophysiology of SpA, including jSpA, is firmly established, the role of the cytokine macrophage migration inhibitory factor (MIF) is generally overlooked. The purpose of this review is to discuss and emphasize the role of epigenetics, neuroendocrine pathways and the hypothalamic-pituitary (HPA) axis, and to propose a novel hypothesis of the role of decreased NLRP3 gene expression and possibly MIF in the early phases of jSpA development. The decreased NLRP3 gene expression in the latter, due to hypomethylation of promotor site, is (one of) the cause for inflammasome malfunction leading to gut dysbiosis observed in patients with early jSpA. In addition, we highlight the role of MIF in the complex innate, adaptive cellular and main effector cytokine network, Finally, since treatment of advanced bone pathology in SpA remains an unmet clinical need, I suggest possible new drug targets with the aim to ultimately improve treatment efficacy and long-term outcome of jSpA patients.

Infliximab induces clinical resolution of sacroiliitis that coincides with increased circulating FOXP3+ T cells in a patient with IPEX syndrome

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a rare monogenic primary immunodeficiency due to mutations of FOXP3, a master transcription factor of regulatory T cells (Treg). IPEX syndrome leads to fatal course in most cases during early childhood or severe multi-organ immune-mediated disorders in patients who survive. Currently hematopoietic stem cell transplantation represents the only known effective cure for IPEX syndrome. However, older patients with a mild disease not severe enough to justify transplantation, raise concerns regarding the appropriate therapeutic management, which is therefore based on supportive and replacement therapies combined with pharmacological immunosuppression. Herein, we report the case of a 22-year-old man with an incomplete IPEX syndrome without endocrine disorders having suffered from severe enteropathy since his birth treated with a combination of various immunosuppressant agents. He developed severe exacerbation of inflammatory low back pain in relation to sacroiliitis. Eventually, infliximab was initiated to control his back pain with rapid resolution as well as digestive improvement and also reduced biological inflammatory markers. In parallel, flow cytometry analysis revealed an increase in the frequency of circulating FOXP3+ CD4+ Treg cells. Altogether these data highlight that anti-TNF may represent a promising therapeutic option in patients with IPEX syndrome.

IL-12/23p40 overproduction by dendritic cells leads to an increased Th1 and Th17 polarization in a model of Yersinia enterocolitica-induced reactive arthritis in TNFRp55-/- mice

Dendritic cells (DCs) play critical functions in the initiation of immune responses. Understanding their role in reactive arthritis (ReA) will help delineate the pathogenesis of this arthropathy. In early studies, we detected IL-12/23p40 deregulation in Yersinia entercolitica (Ye)-induced ReA in TNFRp55-deficient (TNFRp55^-/-) mice. In this study, we assessed the contribution of DCs in this overproduction. First, greater levels of IL-12/23p40, IFN-γand IL-17A were confirmed in supernatants of lipopolysaccharide (LPS)-stimulated TNFRp55^-/-splenocytes obtained on arthritis onset (day 14 after Ye infection). Later, DCs were identified as a precise source of IL-12/23p40 since increased frequency of splenic IL-12/23p40⁺DCs was detected in TNFRp55^-/- mice. After robust in vivo amplification of DCs by injection of Fms-like tyrosine kinase 3-Ligand (Flt3L)-transfected BL16 melanoma, DCs were purified. These cells recapitulated the higher production of IL-12/23p40 under TNFRp55deficiency. In agreement with these results, TNFRp55^-/- DCs promoted Th1 and Th17 programs by co-culture with WT CD4⁺lymphocytes. A mechanistic study demonstrated that JNK and p38 MAPK pathways are involved in IL-12/23p40 overproduction in purified TNFRp55^-/- DCs as well as in the JAWS II cell line. This deregulation was once again attributed to TNFRp55 deficiency since CAY10500, a specific inhibitor of this pathway, compromised TNF-mediated IL-12/23p40 control in LPS-stimulated WT DCs. Simultaneously, this inhibition reduced IL-10 production, suggesting its role mediating IL-12/23p40 regulation by TNFRp55 pathway. These results provide experimental data on the existence of a TNFRp55-mediated anti-inflammatory circuit in DCs. Moreover, these cells may be considered as a novel target in the treatment of ReA.

DCs sensitized with mPD-L1-Ig fusion protein improve the effect of heart transplantation in mice by promoting the generation of T-reg cells

PURPOSE

To detect the effects of DCs sensitized by mPD-L1-Ig fusion protein in heart transplantation in mice as well as its mechanisms.

METHOD

The mPD-L1-IgG1 construct was used to build a yeast expression system, and the fusion protein was expressed by secretion after the transfection of the GS115 yeast strain, purified by affinity chromatography and ion exchange chromatography, and assayed by SDS-PAGE and Western blot. The ability of the fusion protein to bind to the acceptor PD-1 was tested by ELISA, and the ability of the fusion protein to inhibit the function of T cells was tested by mixed lymphocyte reaction (MLR).

RESULTS

We used the new PD-L1-IgG1 fusion protein to sensitize imDCs and maintained the immature state of DCs, so as to induce stable and effective immune tolerance to heart transplantation. After the treatment of DCs by mPD-L1-Ig in vitro, the levels of CD80, CD40 and I-Ab expression on DCs are relatively weaker, the ability of DCs to stimulates the proliferation of allogeneic spleen T cells was significantly decreased (P<0.01), and the levels of Th1 (IL-2, IFN-γ) and Th2 (IL-4, IL-10) secreted by induced allogeneic T cells were significantly decreased (P<0.01). An in vivo experiment also revealed that DCs sensitized by mPD-L1-IgG1 could prolong the survival time of a transplanted heart to 17.8±1.12days, and alleviate the pathological change of the cardiac allografts compared with other three groups.

CONCLUSION

DCs sensitized by the yeast-expressed mPD-L1-Ig fusion protein are shown to alleviate the cardiac allograft rejection in mice.