IL-9 receptor: Regulatory role on FLS and pannus formation

Effects of dioscin from Dioscorea nipponica on TL1A/DR3 and Th9 cells in a collagen-induced arthritis mouse model

Rheumatoid arthritis (RA) is a systemic autoimmune disease, and TL1A and its receptor DR3 play important roles in its pathogenesis. Th9 cells are involved in RA development. Dioscin from Dioscorea nipponica (DDN) has a therapeutic effect on RA, but its effect on TL1A/DR3 and Th9 cells remains unclear. A collagen-induced arthritis (CIA) model was established in DBA/1 mice, and the therapeutic effects of DDN were determined using pathological sections and arthritis index scores. Western blotting and PCR were used to detect TL1A, DR3, PU.1, TGF-β and IRF-4. Enzyme-linked immunosorbent assay was used to detect the expression of TL1A and IL-9 in the serum. Immunofluorescence was used to detect the localization and expression of TL1A, DR3, and PU.1 in synovial tissue. Flow cytometry was used to detect TL1A and DR3 expression in different immune cells and Th9 cells. DDN ameliorated bone destruction, inflammatory cell infiltration, synovial inflammation, cartilage tissue destruction, and proteoglycan loss. DDN downregulated TL1A, DR3, and PU.1 in the synovium of the lymph nodes and spleen and TL1A and IL-9 in the serum. DDN decreased the number of TL1A-expressing APCs and macrophages, DR3-expressing CD4 + T cells, and Th9 cells. Th9 cell differentiation-related factors TGF-β and IRF-4 were also inhibited by DDN. We conclude that DNN inhibited the expression of TL1A/DR3 in CIA mice and suppressed the expression of the Th9 cell-specific transcription factor PU.1, Th9 cell number, and IL-9 secretion. DDN inhibited the function of Th9 cells by targeting TGF-β and IRF-4 in the TL1A/DR3 pathway, thereby reducing inflammation.

Circulating inflammatory cytokines and hypertensive disorders of pregnancy: a two-sample Mendelian randomization study

Background

Hypertensive disorders of pregnancy (HDP) pose a significant risk to maternal and fetal well-being; however, the etiology and pathogenesis of HDP remain ambiguous. It is now widely acknowledged that inflammatory response and the immune system are closely related to HDP. Previous research has identified several inflammatory cytokines are associated with HDP. This study applied Mendelian randomization (MR) analysis to further assess causality.

Methods

Patients with HDP who participated in the MR analysis presented with four types of HDP: pre-eclampsia or eclampsia (PE); gestational hypertension (GH); pre-existing hypertension complicating pregnancy, childbirth and the puerperium (EH); and pre-eclampsia or poor fetal growth (PF). A two-sample MR analysis was used to analyze the data in the study. The causal relationship between exposure and outcome was analyzed with inverse variance weighting (IVW), MR Egger, weighted median, weighted mode, and simple mode methods, where IVW was the primary method employed.

Results

Our MR analysis demonstrated a reliable causative effect of Interleukin-9 (IL-9) and macrophage migration inhibitory factor (MIF) on reducing HDP risk, while macrophage inflammatory protein 1-beta (MIP1b), Interleukin-13 (IL-13), and Interleukin-16 (IL-16) were associated with promoting HDP risk.

Conclusions

This study demonstrated that IL-9, MIF, MIP1b, IL-13, and IL-16 may be cytokines associated with the etiology of HDP, and that a number of inflammatory cytokines are probably involved in the progression of HDP. Additionally, our study revealed that these inflammatory cytokines have causal associations with HDP and may likely be potential therapeutic targets for HDP.

Characterization of chicken interleukin-9 receptor alpha chain

Interleukin-9 receptor alpha chain (IL-9Rα) is the ligand-binding subunit of IL-9R that plays roles in IL-9-mediated allergy, inflammation, infection, and tumor immunity. While mammalian IL-9Rαs have been extensively investigated, avian IL-9Rα has not yet been identified and characterized. In this study, we cloned chicken IL-9Rα (chIL-9Rα) and performed a phylogenetic analysis, analyzed its tissue distribution, characterized the expression form of natural chIL-9Rα. Phylogenetic analysis showed that chIL-9Rα has less than 25% amino acid homology with mammalian IL-9Rαs. The chIL-9Rα mRNA was abundantly detected only in heart and mitogen-activated peripheral blood mononuclear cells. Furthermore, 4 monoclonal antibodies (mAbs) against chIL-9Rα were generated using prokaryotic recombinant chIL-9Rα (rchIL-9Rα). Using anti-chIL-9Rα mAbs, natural chIL-9Rα expressed on the splenocytes of chickens was observed by indirect immunofluorescence assay (IFA), and its molecular weight of 51 kDa was identified by Western blotting. Overall, our study reveals for the first time the presence of IL-9Rα in birds, and provides immunological tools for further investigating the roles of chIL-9 in diseases and immunity.

JAK-STAT inhibitors in Immune mediated diseases: An Overview

For any biological response, transmission of extracellular signals to the nucleus is required for DNA transcription and gene expression. In that respect, cytokines/chemokines are well-known inflammatory agents which play a critical role in signalling pathways by activating the Janus kinase-signal transducers and activators of transcription (JAK-STAT) signalling proteins (Janus kinase-signal transducers and activators of transcription) which are a group of intracellular kinase molecules. Cytokines are a category of small proteins (∼5-25 kDa) that play a major role in cell signalling and are major drivers of an autoimmune response. Here we will discuss the role of Janus kinase-signal transducers and activators of transcription kinase cascades in the inflammatory-proliferative cascades of autoimmune disease and about the recent progress in the development of oral synthetic Janus kinase inhibitors (JAKi) and their therapeutic efficacies in dermatologic and systemic autoimmune diseases. Therapeutic efficacy of Janus kinase inhibitors is now well established in the treatment of array of autoimmune and inflammatory disease: spondylarthritis with a special focus on psoriatic arthritis (PsA) and its dermatologic manifestations (psoriasis) and ankylosing spondylitis (AS), atopic dermatitis (AD), alopecia areata (AA), rheumatoid arthritis (RA) and inflammatory bowel disease (IBD). In addition to the first-generation Janus kinase inhibitors several new-generation Janus kinase inhibitors are currently being evaluated. It is expected that these Janus kinase inhibitors likely have higher potency and less adverse effects as compared to their predecessors. Here we have discussed: (1) the functional significance of the Janus kinase-signal transducers and activators of transcription kinase cascades in the inflammatory-proliferative processes of autoimmune diseases and its cellular/molecular mechanisms and (2) progress in the development of oral synthetic Janus kinase inhibitors and their therapeutic efficacies in several systemic and cutaneous autoimmune diseases.

Histopathology of Psoriatic Arthritis Synovium—A Narrative Review

Psoriatic arthritis (PsA) is a phenotypically heterogeneous chronic inflammatory disease associated to type I major histocompatibility complex alleles whose complex pathogenesis is still not completely understood. The psoriatic synovium shares general features of chronic inflammation with rheumatoid arthritis (RA) and other arthritis, such as hyperplasia of the intimal lining layer, sublining influx of inflammatory cells and neoangiogenesis, but recognizing disease-specific histopathologic findings may help in diagnosis and definition of therapeutic targets. Available literature reports conflicting data regarding the extension of lining hyperplasia, that does not allow depiction from RA. Sublining inflammatory cells consist of T and B cells and macrophages, plasma cells, mast cells and follicular dendritic cells, with a higher amount of overall T, mast cell and IL-17 producing CD8+ T lymphocytes and lower proportion of plasma cells when compared to the rheumatoid synovium. The amount of synovium IL17+ CD8+ T cells correlates positively to measures of disease activity. Lymphoid follicles with characteristics of germinal centers have been identified, similar to the ones described in RA. Neoangiogenesis is more prominent in PsA but can also be an outstanding feature in some RA samples, and different molecules involved in the process appear to have different influence in each disease. IL-17 and IL-22 expression in the synovium does not allow depiction between diseases. Among other cytokines and molecules likely implicated in disease physiopathology, only IL-35 is demonstrated to be reduced in PsA when compared to RA.

Interplay Between Iron Overload and Osteoarthritis: Clinical Significance and Cellular Mechanisms

There are multiple diseases or conditions such as hereditary hemochromatosis, hemophilia, thalassemia, sickle cell disease, aging, and estrogen deficiency that can cause iron overload in the human body. These diseases or conditions are frequently associated with osteoarthritic phenotypes, such as progressive cartilage degradation, alterations in the microarchitecture and biomechanics of the subchondral bone, persistent joint inflammation, proliferative synovitis, and synovial pannus. Growing evidences suggest that the conditions of pathological iron overload are associated with these osteoarthritic phenotypes. Osteoarthritis (OA) is an important complication in patients suffering from iron overload-related diseases and conditions. This review aims to summarize the findings and observations made in the field of iron overload-related OA while conducting clinical and basic research works. OA is a whole-joint disease that affects the articular cartilage lining surfaces of bones, subchondral bones, and synovial tissues in the joint cavity. Chondrocytes, osteoclasts, osteoblasts, and synovial-derived cells are involved in the disease. In this review, we will elucidate the cellular and molecular mechanisms associated with iron overload and the negative influence that iron overload has on joint homeostasis. The promising value of interrupting the pathologic effects of iron overload is also well discussed for the development of improved therapeutics that can be used in the field of OA.

Janus kinase-signal transducers and activators of transcription cell signaling in Spondyloarthritis: rationale and evidence for JAK inhibition

PURPOSE OF REVIEW

The Janus kinase-signal transducers and activators of transcription (JAK-STAT) signaling proteins represent a group of intracellular kinase molecules that play a central role in the signaling pathways induced by cytokines, chemokines, and certain growth factors associated with systemic and local inflammation of autoimmune diseases including in Spondyloarthritis (SpA). Here, we will discuss (i) the functional significance of the JAK-STAT kinase cascades in the inflammatory-proliferative processes of SpA and its cellular/molecular mechanisms (ii) progress in the development of oral synthetic JAK inhibitors (JAKi) and their therapeutic efficacies in SpA.

RECENT FINDINGS

Development JAKi is a fast-moving field in the medical science. Several new-generation JAKi are being identified for psoriatic arthritis and ankylosing spondylitis. It is expected these JAKi likely to have higher potency and less adverse effects.

SUMMARY

Here, we are providing an updated review on the significance of JAK-STAT signaling proteins in SpA with an emphasis on new-generation of JAK-STAT inhibitors for the treatment of SpA.

Disruptive Selection of Human Immunostimulatory and Immunosuppressive Genes Both Provokes and Prevents Rheumatoid Arthritis, Respectively, as a Self-Domestication Syndrome

Using our previously published Web service SNP_TATA_Comparator, we conducted a genome-wide study of single-nucleotide polymorphisms (SNPs) within core promoters of 68 human rheumatoid arthritis (RA)-related genes. Using 603 SNPs within 25 genes clinically associated with RA-comorbid disorders, we predicted 84 and 70 candidate SNP markers for overexpression and underexpression of these genes, respectively, among which 58 and 96 candidate SNP markers, respectively, can relieve and worsen RA as if there is a neutral drift toward susceptibility to RA. Similarly, we predicted natural selection toward susceptibility to RA for 8 immunostimulatory genes (e.g., IL9R) and 10 genes most often associated with RA (e.g., NPY). On the contrary, using 25 immunosuppressive genes, we predicted 70 and 109 candidate SNP markers aggravating and relieving RA, respectively (e.g., IL1R2 and TGFB2), suggesting that natural selection can simultaneously additionally yield resistance to RA. We concluded that disruptive natural selection of human immunostimulatory and immunosuppressive genes is concurrently elevating and reducing the risk of RA, respectively. So, we hypothesize that RA in human could be a self-domestication syndrome referring to evolution patterns in domestic animals. We tested this hypothesis by means of public RNA-Seq data on 1740 differentially expressed genes (DEGs) of pets vs. wild animals (e.g., dogs vs. wolves). The number of DEGs in the domestic animals corresponding to worsened RA condition in humans was significantly larger than that in the related wild animals (10 vs. 3). Moreover, much less DEGs in the domestic animals were accordant to relieved RA condition in humans than those in the wild animals (1 vs. 8 genes). This indicates that the anthropogenic environment, in contrast to a natural one, affects gene expression across the whole genome (e.g., immunostimulatory and immunosuppressive genes) in a manner that likely contributes to RA. The difference in gene numbers is statistically significant as confirmed by binomial distribution (p < 0.01), Pearson's χ² (p < 0.01), and Fisher's exact test (p < 0.05). This allows us to propose RA as a candidate symptom within a self-domestication syndrome. Such syndrome might be considered as a human's payment with health for the benefits received during evolution.

Novel immune cell phenotypes in spondyloarthritis pathogenesis

Spondyloarthritis (SpA) is a heterogeneous group of chronic inflammatory diseases of unknown etiology. Over time, the plethora of cellular elements involved in its pathogenesis has progressively enriched together with the definition of specific cytokine pathways. Recent evidence suggests the involvement of new cellular mediators of inflammation in the pathogenesis of SpA or new subgroups of known cellular mediators. The research in this sense is ongoing, and it is clear that this challenge aimed at identifying new cellular actors involved in the perpetuation of the inflammatory process in AxSpA is not a mere academic exercise but rather aims to define a clear cellular hierarchy. Such a definition could pave the way for new targeted therapies, which could interfere with the inflammatory process and specific pathways that trigger immune system dysregulation and stromal cell activity, ultimately leading to significant control of the inflammation and new bone formation in a significant number of patients. In this review, we will describe the recent advances in terms of new cellular actors involved in the pathogenesis of SpA, focusing our attention on stromal cells and innate and adaptive immunity cells.

Genes that escape from X-chromosome inactivation: Potential contributors to Klinefelter syndrome

One of the two X chromosomes in females is epigenetically inactivated, thereby compensating for the dosage difference in X-linked genes between XX females and XY males. Not all X-linked genes are completely inactivated, however, with 12% of genes escaping X chromosome inactivation and another 15% of genes varying in their X chromosome inactivation status across individuals, tissues or cells. Expression of these genes from the second and otherwise inactive X chromosome may underlie sex differences between males and females, and feature in many of the symptoms of XXY Klinefelter males, who have both an inactive X and a Y chromosome. We review the approaches used to identify genes that escape from X-chromosome inactivation and discuss the nature of their sex-biased expression. These genes are enriched on the short arm of the X chromosome, and, in addition to genes in the pseudoautosomal regions, include genes with and without Y-chromosomal counterparts. We highlight candidate escape genes for some of the features of Klinefelter syndrome and discuss our current understanding of the mechanisms underlying silencing and escape on the X chromosome as well as additional differences between the X in males and females that may contribute to Klinefelter syndrome.

Decreased placental IL9 and IL9R in preeclampsia impair trophoblast cell proliferation, invasion, and angiogenesis

OBJECTIVE

Our study aimed to investigate IL9 and IL9R expression in preeclampsia and assess their effects on trophoblast biological behaviors.

METHODS

IL9 and IL9R expression of placenta tissue were evaluated by immunochemistry and q-PCR. Using transwell, CCK-8, and tubule formation assays measured invasion, proliferation and angiogenesis of trophoblast with adding IL9 or anti-IL9R antibody.

RESULTS

IL9 and IL9R levels were significantly decreased in preeclampsia. IL9 improved trophoblast activities. Blocking IL9/IL9R resulted in decreased proliferation, invasion, and tube-formation capability of trophoblast.

CONCLUSIONS

IL9 and IL9R contribute to the pathogenesis of preeclampsia. IL9/IL9R signaling provides a new potential therapeutic target for preventing preeclampsia.

Functional significance of MAIT cells in psoriatic arthritis

BACKGROUND

Mucosal-associated invariant T (MAIT) cells are gaining more relevance for autoimmune diseases because of its (i) innate and adaptive immune response (ii) tissue homing properties (iii) production of IL-17A. These cells are predominantly CD8⁺ cells, because of its strong association with MHC-I. Tc17 CD8+/MAIT cells likely to have a critical role in psoriatic arthritis (PsA). Herein, we have explored pathological significance of MAIT cell in PsA.

METHODS

Peripheral blood mononuclear cells (PBMC) and synovial fluid mononuclear cells (SFMC) were collected from age/sex matched (n = 10 for each) PsA, rheumatoid arthritis (RA) and osteoarthritis patients (OA). Hi-D FACS studies were performed: (i) activated memory cells (CD3⁺CD45RO⁺) T cells were identified (ii) gating strategies were made to identity the MAIT (CD3⁺Vα7.2TCR⁺CD161^hi) cells, its phenotype pattern; and functional significance in respect to IL-17A production and responsiveness to human rIL-23. Anti CD3/CD28 ab cocktail was used to activate cells along with rIL-23 to culture and enrich the MAIT cells. The percentages of each cell population and the mean fluorescence intensity (MFI) were analyzed using Flow Jo software.

RESULTS

MAIT cells were enriched in synovial fluid of PsA (4.29 ± 0.82%) compared to PBMC (1.04 ± 0.71). With stimulation, SFMC MAIT cells produced significantly more IL-17A (32.66 ± 4.01%) compared to that of RA (23.93 ± 2.81%, p < 0.05) and OA (5.02 ± 0.16%, p < 0.05). MAIT cells were predominantly CD8⁺ (>80%). Significant upregulation of IL-23R was noted in synovial fluid MAIT cells of PsA (24.97 ± 2.33%, p < 0.001) and RA (21.93 ± 2.29%, p < 0.001) compared to that of OA (2.13 ± 2.29). This IL-23R was functionally active as evidenced by profound mitotic effect in presence of rIL-23.

CONCLUSION

MAIT cells are poly functional; produce multiple cytokines (IL-17A, IFN-γ, TNF-α). Here, we demonstrated synovial fluid MAIT cells as a major source of IL-17A and majority of MAIT cells were CD8⁺. Functionally active IL-23R on these migrated MAIT cells brings a new dimension. They may not need MR1 associated activation rather lesional IL-23 in the synovium can independently regulate these critical Tc17 CD8⁺ MAIT cells. Thus, these cells likely to be a part of the IL-23/IL-17A cytokine network and play a critical role in the pathogenesis of PsA.