IL-27 regulates IL-12 responsiveness of naive CD4+ T cells through Stat1-dependent and -independent mechanisms

Novel Dairy Fermentates Have Differential Effects on Key Immune Responses Associated with Viral Immunity and Inflammation in Dendritic Cells

Fermented foods and ingredients, including furmenties derived from lactic acid bacteria (LAB) in dairy products, can modulate the immune system. Here, we describe the use of reconstituted skimmed milk powder to generate novel fermentates from Lactobacillus helveticus strains SC232, SC234, SC212, and SC210, and from Lacticaseibacillus casei strains SC209 and SC229, and demonstrate, using in vitro assays, that these fermentates can differentially modulate cytokine secretion via bone-marrow-derived dendritic cells (BMDCs) when activated with either the viral ligand loxoribine or an inflammatory stimulus, lipopolysaccharide. Specifically, we demonstrate that SC232 and SC234 increase cytokines IL-6, TNF-α, IL-12p40, IL-23, IL-27, and IL-10 and decrease IL-1β in primary bone-marrow-derived dendritic cells (BMDCs) stimulated with a viral ligand. In contrast, exposure of these cells to SC212 and SC210 resulted in increased IL-10, IL-1β, IL-23, and decreased IL-12p40 following activation of the cells with the inflammatory stimulus LPS. Interestingly, SC209 and SC229 had little or no effect on cytokine secretion by BMDCs. Overall, our data demonstrate that these novel fermentates have specific effects and can differentially enhance key immune mechanisms that are critical to viral immune responses, or can suppress responses involved in chronic inflammatory conditions, such as ulcerative colitis (UC), and Crohn's disease (CD).

IL-27 expression regulation and its effects on adaptive immunity against viruses

IL-27, a member of the IL-6/IL-12 cytokine superfamily, is primarily secreted by antigen presenting cells, specifically by dendric cells, macrophages and B cells. IL-27 has antiviral activities and modulates both innate and adaptive immune responses against viruses. The role of IL-27 in the setting of viral infections is not well defined and both pro-inflammatory and anti-inflammatory functions have been described. Here, we discuss the latest advancements in the role of IL-27 in several viral infection models of human disease. We highlight important aspects of IL-27 expression regulation, the critical cell sources at different stages of the infection and their impact in cell mediated immunity. Lastly, we discuss the need to better define the antiviral and modulatory (pro-inflammatory vs anti-inflammatory) properties of IL-27 in the context of human chronic viral infections.

Interleukin 27, Similar to Interferons, Modulates Gene Expression of Tripartite Motif (TRIM) Family Members and Interferes with Mayaro Virus Replication in Human Macrophages

BACKGROUND

The Tripartite motif (TRIM) family includes more than 80 distinct human genes. Their function has been implicated in regulating important cellular processes, including intracellular signaling, transcription, autophagy, and innate immunity. During viral infections, macrophages are key components of innate immunity that produce interferons (IFNs) and IL27. We recently published that IL27 and IFNs induce transcriptional changes in various genes, including those involved in JAK-STAT signaling. Furthermore, IL27 and IFNs share proinflammatory and antiviral pathways in monocyte-derived macrophages (MDMs), resulting in both common and unique expression of inflammatory factors and IFN-stimulated genes (ISGs) encoding antiviral proteins. Interestingly, many TRIM proteins have been recognized as ISGs in recent years. Although it is already very well described that TRIM expression is induced by IFNs, it is not fully understood whether TRIM genes are induced in macrophages by IL27. Therefore, in this study, we examined the effect of stimulation with IL27 and type I, II, and III IFNs on the mRNA expression profiles of TRIM genes in MDMs.

METHODS

We used bulk RNA-seq to examine the TRIM expression profile of MDMs treated with IFNs or IL27. Initially, we characterized the expression patterns of different TRIM subfamilies using a heatmap. Subsequently, a volcano plot was employed to identify commonly differentially expressed TRIM genes. Additionally, we conducted gene ontology analysis with ClueGO to explore the biological processes of the regulated TRIMs, created a gene-gene interaction network using GeneMANIA, and examined protein-protein interactions with the STRING database. Finally, RNA-seq data was validated using RT-qPCR. Furthermore, the effect of IL27 on Mayaro virus replication was also evaluated.

RESULTS

We found that IL27, similar to IFNs, upregulates several TRIM genes' expression in human macrophages. Specifically, we identified three common TRIM genes (TRIM19, 21, and 22) induced by IL27 and all types of human IFNs. Additionally, we performed the first report of transcriptional regulation of TRIM19, 21, 22, and 69 genes in response to IL27. The TRIMs involved a broad range of biological processes, including defense response to viruses, viral life cycle regulation, and negative regulation of viral processes. In addition, we observed a decrease in Mayaro virus replication in MDMs previously treated with IL27.

CONCLUSIONS

Our results show that IL27, like IFNs, modulates the transcriptional expression of different TRIM-family members involved in the induction of innate immunity and an antiviral response. In addition, the functional analysis demonstrated that, like IFN, IL27 reduced Mayaro virus replication in MDMs. This implies that IL27 and IFNs share many similarities at a functional level. Moreover, identifying distinct TRIM groups and their differential expressions in response to IL27 provides new insights into the regulatory mechanisms underlying the antiviral response in human macrophages.

Interleukin 27, like interferons, activates JAK-STAT signaling and promotes pro-inflammatory and antiviral states that interfere with dengue and chikungunya viruses replication in human macrophages

Interferons (IFNs) are a family of cytokines that activate the JAK-STAT signaling pathway to induce an antiviral state in cells. Interleukin 27 (IL-27) is a member of the IL-6 and/or IL-12 family that elicits both pro- and anti-inflammatory responses. Recent studies have reported that IL-27 also induces a robust antiviral response against diverse viruses, both in vitro and in vivo, suggesting that IFNs and IL-27 share many similarities at the functional level. However, it is still unknown how similar or different IFN- and IL-27-dependent signaling pathways are. To address this question, we conducted a comparative analysis of the transcriptomic profiles of human monocyte-derived macrophages (MDMs) exposed to IL-27 and those exposed to recombinant human IFN-α, IFN-γ, and IFN-λ. We utilized bioinformatics approaches to identify common differentially expressed genes between the different transcriptomes. To verify the accuracy of this approach, we used RT-qPCR, ELISA, flow cytometry, and microarrays data. We found that IFNs and IL-27 induce transcriptional changes in several genes, including those involved in JAK-STAT signaling, and induce shared pro-inflammatory and antiviral pathways in MDMs, leading to the common and unique expression of inflammatory factors and IFN-stimulated genes (ISGs)Importantly, the ability of IL-27 to induce those responses is independent of IFN induction and cellular lineage. Additionally, functional analysis demonstrated that like IFNs, IL-27-mediated response reduced chikungunya and dengue viruses replication in MDMs. In summary, IL-27 exhibits properties similar to those of all three types of human IFN, including the ability to stimulate a protective antiviral response. Given this similarity, we propose that IL-27 could be classified as a distinct type of IFN, possibly categorized as IFN-pi (IFN-π), the type V IFN (IFN-V).

Interleukin-12: Structure, Function, and Its Impact in Colorectal Cancer

Interleukin 12 (IL-12) is a heterodimer consisting of 2 subunits, p35 and p40, with unique associations and interacting functions with its family members. IL-12 is one of the most important cytokines regulating the immune system response and is integral to adaptive immunity. IL-12 has shown marked therapeutic potential in a variety of tumor types. This review therefore summarizes the characteristics of IL-12 and its application in tumor treatment, focusing on its antitumor effects in colorectal cancer (CRC) and potential radiosensitization mechanisms. We aim to provide a current reference for IL-12 and other potential CRC treatment strategies.

An updated advancement of bifunctional IL-27 in inflammatory autoimmune diseases

Interleukin-27 (IL-27) is a member of the IL-12 family. The gene encoding IL-27 is located at chromosome 16p11. IL-27 is considered as a heterodimeric cytokine, which consists of Epstein-Barr virus (EBV)-induced gene 3 (Ebi3) and IL-27p28. Based on the function of IL-27, it binds to receptor IL-27rα or gp130 and then regulates downstream cascade. To date, findings show that the expression of IL-27 is abnormal in different inflammatory autoimmune diseases (including systemic lupus erythematosus, rheumatoid arthritis, Sjogren syndrome, Behcet's disease, inflammatory bowel disease, multiple sclerosis, systemic sclerosis, type 1 diabetes, Vogt-Koyanagi-Harada, and ankylosing spondylitis). Moreover, in vivo and in vitro studies demonstrated that IL-27 is significantly in3volved in the development of these diseases by regulating innate and adaptive immune responses, playing either an anti-inflammatory or a pro-inflammatory role. In this review, we comprehensively summarized information about IL-27 and autoimmunity based on available evidence. It is hoped that targeting IL-27 will hold great promise in the treatment of inflammatory autoimmune disorders in the future.

The IL-21/IL-21R signaling axis regulates CD4+ T cell responsiveness to IL-12 to promote bacterial-induced colitis

IL-21/IL-21R signaling dysregulation is linked to multiple chronic intestinal inflammatory disorders in humans and animal models of human diseases. In addition to its critical requirement for the generation and development of germinal center B cells, IL-21/IL-21R signaling can also regulate the effector functions of a variety of T cell subsets. The antibody-mediated abrogation of IL-21/IL-21R signaling led to the impaired expression of IFN-γ by mucosal CD4+ T cells from human subjects with colitis, suggesting an IL-21/IL-21R-triggered positive feedback loop of the TH1 immune response in the colon. Despite recent advances in our understanding of the mechanisms underpinning the regulation of pro-inflammatory immune responses by the IL-21/IL-21R signaling axis, it remains unclear how this pathway or its downstream molecules contribute to inflammation during bacterial-induced colitis. This study found that IL-21 enhances the surface expression of IL-12Rβ2, but not IL-12Rβ1, in CD4+ T cells, leading to TH1 differentiation and stability. Consistently, these findings also point to an indispensable role of the IL-12Rβ2 signaling axis in promoting pro-inflammatory immune responses during Citrobacter rodentium-induced colitis. Genetic deletion of the IL-12Rβ2 signaling pathway led to the attenuation of C. rodentium-induced colitis in vivo. The genetic deletion of the IL-12Rβ2 signaling pathway did not alter the host's ability to respond adequately to C. rodentium infection or the ability of Il12rb2-/- mice to express antigen-specific cytokines (IFN-γ, IL-17A). IL-21 is a pleiotropic cytokine exerting a wide range of immunomodulatory functions in multiple tissues, and its direct targeting may result in undesirable off-target consequences. These findings highlight the possibility for targeted manipulations of signaling cascades downstream of main regulators of pro-inflammatory responses to control invading pathogens while preserving the integrity of host immune responses. A better understanding of the novel mechanisms by which IL-21/IL-21R signaling regulates bacterial-induced colitis will provide insights into the development of new therapeutic and preventive strategies to harness IL-21/IL-21R signaling or its downstream molecules to treat infectious colitis.

Interleukin-6 Family of Cytokines in Cancers

Nine soluble ligands [interleukin-6 (IL-6), interleukin-11 (IL-11), leukemia inhibitory factor (LIF), oncostatin M (OSM), ciliary neurotrophic factor (CNTF), cardiotrophin-1 (CT-1), cardiotrophin-like cytokine, interleukin-27 (IL-27), and interleukin-31] share the ubiquitously expressed transmembrane protein-glycoprotein-130 beta-subunit (gp130) and thus form IL-6 family cytokines. Proteins that may be important for cancerogenesis, CT-1, IL-11, IL-27, LIF, OSM, and CNTF, belong to the superfamily of IL-6. Cytokines such as IL-6, IL-11, and IL-27 are better investigated in comparison with other members of the same family of cytokines, eg, CT-1. Gp130 is one of the main receptors through which these cytokines exert their effects. The clinical implication of understanding the pathways of these cytokines in oncology is that targeted therapy to inhibit or potentiate cytokine activity may lead to remission in some cases.

Targeting TYK2 for Fighting Diseases: Recent Advance of TYK2 Inhibitors

TYK2 (tyrosine-protein kinase 2) is a non-receptor protein kinase belonging to the JAK family and is closely associated with various diseases, such as psoriasis, inflammatory bowel disease, systemic lupus erythematosus. TYK2 activates the downstream proteins STAT1-5 by participating in the signal transduction of immune factors such as IL-12, IL-23, and IL-10, resulting in immune expression. The activity of the inhibitor TYK2 can effectively block the transduction of excessive immune signals and treat diseases. TYK2 inhibitors are divided into two types of inhibitors according to the different binding sites. One is a TYK2 inhibitor that binds to JH2 and inhibits its activity through an allosteric mechanism. The representative inhibitor is BMS-986165, developed by Bristol-Myers Squibb. The other class binds to the JH1 adenosine triphosphate (ATP) site and prevents the catalytic activity of the kinase by blocking ATP and downstream phosphorylation. This paper mainly introduces the protein structure, signaling pathway, synthesis, structure-activity relationship and clinical research of TYK2 inhibitors.

Evolutionarily conserved IL-27β enhances Th1 cells potential by triggering the JAK1/STAT1/T-bet axis in Nile tilapia

As a pleiotropic cytokine in the interleukin (IL)-12 family, IL-27β plays a significant role in regulating immune cell responses, eliminating invading pathogens, and maintaining immune homeostasis. Although non-mammalian IL-27β homologs have been identified, the mechanism of whether and how it is involved in adaptive immunity in early vertebrates remains unclear. In this study, we identified an evolutionarily conserved IL-27β (defined as OnIL-27β) from Nile tilapia (Oreochromis niloticus), and explored its conserved status through gene collinearity, gene structure, functional domain, tertiary structure, multiple sequence alignment, and phylogeny analysis. IL-27β was widely expressed in the immune-related tissues/organ of tilapia. The expression of OnIL-27β in spleen lymphocytes increased significantly at the adaptive immune phase after Edwardsiella piscicida infection. OnIL-27β can bind to precursor cells, T cells, and other lymphocytes to varying degrees. Additionally, IL-27β may be involved in lymphocyte-mediated immune responses through activation of Erk and JNK pathways. More importantly, we found that IL-27β enhanced the mRNA expression of the Th1 cell-associated cytokine IFN-γ and the transcription factor T-bet. This potential enhancement of the Th1 response may be attributed to the activation of the JAK1/STAT1/T-bet axis by IL-27β, as it induced increased transcript levels of JAK1, STAT1 but not TYK2 and STAT4. This study provides a new perspective for understanding the origin, evolution and function of the adaptive immune system in teleost.

Critical influence of cytokines and immune cells in autoimmune gastritis

Gastric cancer (GC) is a type of the most common cancers. Autoimmune gastritis (AIG) and infection with Helicobacter pylori (HP) are the risk factors of triggering GC. With the emphasis on the treatment of HP, the incidence and prevalence of HP infection in population is decreasing. However, AIG lacks accurate diagnosis and treatment methods, which occupies high cancer risk factors. AIG is controlled by the immune environment of the stomach, including immune cells, inflammatory cells, and infiltrating intercellular material. Various immune cells or cytokines play a central role in the process of regulating gastric parietal cells. Abnormal expression levels of cytokines involved in immunity are bound to face the risk of tumorigenesis. Therefore, it is particularly important for preventing or treating AIG and avoiding the risk of gastric cancer to clarify the confirmed action mode of immune cells and cytokines in the gastric system. Herein, we briefly reviewed the role of the immune environment under AIG, focussing on describing these double-edged effects between immune cells and cytokines, and pointing out potential research challenges.

Association of IL-17 and IL-27 polymorphisms with susceptibility to recurrent pregnancy loss and pre-eclampsia: A systematic review and meta-analysis

OBJECTIVE

Recurrent pregnancy loss (RPL) and pre-eclampsia (PE) are immune-related pregnancy complications that have been linked to CD4+ T cells and their cytokines, which can be influenced by genetic polymorphisms. This meta-analysis aimed to investigate the relationship between interleukin (IL)-17 and -27 polymorphisms and the susceptibility to RPL and PE.

METHODS

All eligible case-control studies published up to February 2023 were identified by searching PubMed, EMBASE, Cochrane, Web of Science, and Google Scholar. The risk of recurrent pregnancy loss and PE associated with the IL-17 rs2275913, IL-17 rs763780, IL-27 rs153109, and IL-27 rs17855750 polymorphisms were estimated for each study.

RESULTS

The meta-analysis incorporated a total of 13 studies. The overall analysis indicated that IL-17 rs2275913, IL-17 rs763780, IL-27 rs153109, and IL-27 rs17855750 polymorphisms were not significantly associated with immune-related pregnancy complications, including RPL and PE. However, when the analysis was stratified by disease type, the IL-17 rs2275913 polymorphism was found to be associated with an increased risk of RPL (recessive model AA/GA + GG: OR = 1.68, 95% confidence interval [CI]: 1.13-2.49, p = .01).

CONCLUSIONS

The IL-17 rs763780, IL-27 rs153109, and IL-27 rs17855750 polymorphisms were not significantly associated with RPL and PE, whereas the IL-17 rs2275913 polymorphism was associated with the susceptibility to recurrent miscarriage.

IL-27 Gene Therapy Induces Stat3-Mediated Expansion of CD11b+Gr1+ Myeloid Cells and Promotes Accumulation of M1 Macrophages in the Tumor Microenvironment

IL-27 is a pleiotropic cytokine that exhibits stimulatory/regulatory functions on multiple lineages of immune cells and has a potential to be used as a therapeutic for cancer. We have recently demonstrated that administration of IL-27 producing adeno-associated virus (AAV-IL-27) exhibits potent inhibition of tumor growth in mouse models. In this study, we demonstrate that AAV-IL-27 treatment leads to significant expansion of CD11b+Gr1+ myeloid cells. AAV-IL-27-induced expansion of CD11b+Gr1+ cells is IL-27R-dependent and requires Stat3 signaling, but it is inhibited by Stat1 signaling. AAV-IL-27 treatment does not increase the self-renewal capacity of CD11b+Gr1+ cells but induces significant expansion of Lin-Sca1+c-Kit+ (LSK) and granulocyte-monocyte progenitor cells. Despite exhibiting significant suppression of T cells in vitro, IL-27-induced CD11b+Gr1+ cells lost the tumor-promoting activity in vivo and overall play an antitumor role. In tumors from AAV-IL-27-treated mice, CD11b+Gr1+ cells are largely F4/80+ and express high levels of MHC class I/II and M1 macrophage markers. Thus, IL-27 gene therapy induces Stat3-mediated expansion of CD11b+Gr1+ myeloid cells and promotes accumulation of M1 macrophages in the tumor microenvironment.

T cell intrinsic STAT1 signaling prevents aberrant Th1 responses during acute toxoplasmosis

Infection-induced T cell responses must be properly tempered and terminated to prevent immuno-pathology. Using transgenic mice, we demonstrate that T cell intrinsic STAT1 signaling is required to curb inflammation during acute infection with Toxoplasma gondii. Specifically, we report that mice lacking STAT1 selectively in T cells expel parasites but ultimately succumb to lethal immuno-pathology characterized by aberrant Th1-type responses with reduced IL-10 and increased IL-13 production. We also find that, unlike STAT1, STAT3 is not required for induction of IL-10 or suppression of IL-13 during acute toxoplasmosis. Each of these findings was confirmed in vitro and ChIP-seq data mining showed that STAT1 and STAT3 co-localize at the Il10 locus, as well as loci encoding other transcription factors that regulate IL-10 production, most notably Maf and Irf4. These data advance basic understanding of how infection-induced T cell responses are managed to prevent immuno-pathology and provide specific insights on the anti-inflammatory properties of STAT1, highlighting its role in shaping the character of Th1-type responses.

Deficiencies and Dysregulation of STAT Pathways That Drive Inborn Errors of Immunity: Lessons from Patients and Mouse Models of Disease

The STAT family proteins provide critical signals for immune cell development, differentiation, and proinflammatory and anti-inflammatory responses. Inborn errors of immunity (IEIs) are caused by single gene defects leading to immune deficiency and/or dysregulation, and they have provided opportunities to identify genes important for regulating the human immune response. Studies of patients with IEIs due to altered STAT signaling, and mouse models of these diseases, have helped to shape current understanding of the mechanisms whereby STAT signaling and protein interactions regulate immunity. Although many STAT signaling pathways are shared, clinical and immune phenotypes in patients with monogenic defects of STAT signaling highlight both redundant and nonredundant pathways. In this review, we provide an overview of the shared and unique signaling pathways used by STATs, phenotypes of IEIs with altered STAT signaling, and recent discoveries that have provided insight into the human immune response and treatment of disease.

A flexible liposomal polymer complex as a platform of specific and regulable immune regulation for individual cancer immunotherapy

BACKGROUND

The applicability and therapeutic efficacy of specific personalized immunotherapy for cancer patients is limited by the genetic diversity of the host or the tumor. Side-effects such as immune-related adverse events (IRAEs) derived from the administration of immunotherapy have also been observed. Therefore, regulatory immunotherapy is required for cancer patients and should be developed.

METHODS

The cationic lipo-PEG-PEI complex (LPPC) can stably and irreplaceably adsorb various proteins on its surface without covalent linkage, and the bound proteins maintain their original functions. In this study, LPPC was developed as an immunoregulatory platform for personalized immunotherapy for tumors to address the barriers related to the heterogenetic characteristics of MHC molecules or tumor associated antigens (TAAs) in the patient population. Here, the immune-suppressive and highly metastatic melanoma, B16F10 cells were used to examine the effects of this platform. Adsorption of anti-CD3 antibodies, HLA-A2/peptide, or dendritic cells' membrane proteins (MP) could flexibly provide pan-T-cell responses, specific Th1 responses, or specific Th1 and Th2 responses, depending on the host needs. Furthermore, with regulatory antibodies, the immuno-LPPC complex properly mediated immune responses by adsorbing positive or negative antibodies, such as anti-CD28 or anti-CTLA4 antibodies.

RESULTS

The results clearly showed that treatment with LPPC/MP/CD28 complexes activated specific Th1 and Th2 responses, including cytokine release, CTL and prevented T-cell apoptosis. Moreover, LPPC/MP/CD28 complexes could eliminate metastatic B16F10 melanoma cells in the lung more efficiently than LPPC/MP. Interestingly, the melanoma resistance of mice treated with LPPC/MP/CD28 complexes would be reversed to susceptible after administration with LPPC/MP/CTLA4 complexes. NGS data revealed that LPPC/MP/CD28 complexes could enhance the gene expression of cytokine and chemokine pathways to strengthen immune activation than LPPC/MP, and that LPPC/MP/CTLA4 could abolish the LPPC/MP complex-mediated gene expression back to un-treatment.

CONCLUSIONS

Overall, we proved a convenient and flexible immunotherapy platform for developing personalized cancer therapy.

Differential regulation of lineage-determining transcription factor expression in innate lymphoid cell and adaptive T helper cell subsets

CD4 T helper (Th) cell subsets, including Th1, Th2 and Th17 cells, and their innate counterparts innate lymphoid cell (ILC) subsets consisting of ILC1s, ILC2s and ILC3s, display similar effector cytokine-producing capabilities during pro-inflammatory immune responses. These lymphoid cell subsets utilize the same set of lineage-determining transcription factors (LDTFs) for their differentiation, development and functions. The distinct ontogeny and developmental niches between Th cells and ILCs indicate that they may adopt different external signals for the induction of LDTF during lineage commitment. Increasing evidence demonstrates that many conserved cis-regulatory elements at the gene loci of LDTFs are often preferentially utilized for the induction of LDTF expression during Th cell differentiation and ILC development at different stages. In this review, we discuss the functions of lineage-related cis-regulatory elements in inducing T-bet, GATA3 or RORγt expression based on the genetic evidence provided in recent publications. We also review and compare the upstream signals involved in LDTF induction in Th cells and ILCs both in vitro and in vivo. Finally, we discuss the possible mechanisms and physiological importance of regulating LDTF dynamic expression during ILC development and activation.

Vaccination with an HIV T-cell immunogen induces alterations in the mouse gut microbiota

The gut microbiota is emerging as a crucial factor modulating vaccine responses; however, few studies have investigated if vaccines, in turn, can alter the microbiota and to what extent such changes may improve vaccine efficacy. To understand the effect of T-cell vaccination on the gut microbiome, we administered an HIV-1 T-cell immunogen (HTI arm) or PBS (control, Mock arm) to C57Bl/6 mice following a heterologous prime-boost scheme. The longitudinal dynamics of the mice gut microbiota was characterized by 16 S ribosomal RNA sequencing in fecal samples collected from cages, as well as from three gut sections (cecum, small and large intestine). Serum and spleen cells were obtained at the last time point of the study to assess immune correlates using IFNγ ELISPOT and cytokine Luminex^® assays. Compared with Mock, HTI-vaccinated mice were enriched in Clostridiales genera (Eubacterium xylanophilum group, Roseburia and Ruminococcus) known as primary contributors of anti-inflammatory metabolites, such as short-chain fatty acids. Such shift was observed after the first HTI dose and remained throughout the study follow-up (18 weeks). However, the enriched Clostridiales genera were different between feces and gut sections. The abundance of bacteria enriched in vaccinated animals positively correlated with HTI-specific T-cell responses and a set of pro-inflammatory cytokines, such as IL-6. This longitudinal analysis indicates that, in mice, T-cell vaccination may promote an increase in gut bacteria known to produce anti-inflammatory molecules, which in turn correlate with proinflammatory cytokines, suggesting an adaptation of the gut microbial milieu to T-cell-induced systemic inflammation.

Transcriptional inhibition of STAT1 functions in the nucleus alleviates Th1 and Th17 cell-mediated inflammatory diseases

T helper 1 cells (Th1 cells) and T helper 17 cells (Th17 cells) play pivotal roles in the pathogenesis of various autoimmune diseases, including psoriasis and inflammatory bowel disease (IBD). Signal transducer and activator of transcription 1 (STAT1) regulates the Th1 and Th17 cell lineage commitment at an early stage and maintains their immunological functions in vitro and in vivo. The previous strategies to block STAT1 functions to treat autoimmune diseases inhibit Th1 cell activity but simultaneously cause hyper-activation of Th17 cells. Herein, to modulate the functions of pathogenic Th1 and Th17 cells without genetic modification in normal physiological conditions, we generated the nucleus-deliverable form of the transcription modulation domain of STAT1 (ndSTAT1-TMD), which can be transduced into the nucleus of the target cells in a dose- and time-dependent manner without affecting the cell viability and T cell activation signaling events. ndSTAT1-TMD significantly blocked the differentiation of naïve CD4+ T cells into Th1 or Th17 cells via competitive inhibition of endogenous STAT1-mediated transcription, which did not influence Th2 and Treg cell differentiation. When the gene expression profile of Th1 or Th17 cells after ndSTAT1-TMD treatment was analyzed by mRNA sequencing, the expression of the genes involved in the differentiation capacity and the immunological functions of Th1 or Th17 cells were substantially reduced. The therapeutic potential of ndSTAT1-TMD was tested in the animal model of psoriasis and colitis, whose pathogenesis is mainly contributed by Th1 or/and Th17 cells. The symptoms and progression of psoriasis and colitis were significantly alleviated by ndSTAT1-TMD treatment, comparable to anti-IL-17A antibody treatment. In conclusion, our study demonstrates that ndSTAT1-TMD can be a new therapeutic reagent for Th1/17 cell-mediated autoimmune diseases by modulating the functions of pathogenic Th1 and Th17 cells together.

Transient B-cell depletion and regulatory T-cells mediation in combination with adenovirus mediated IGF-1 prevents and reverses autoimmune diabetes in NOD mice

Type 1 diabetes (T1D) is one of the T cells mediated autoimmune diseases, although B cells also play an important role in the development. Both T cell and B cell targeted immunotherapies exhibited efficacies in preventing and reversing the T1D. Current study was performed to investigate the protective effects of anti-CD20/CD3 bi-specific antibody (bsAb) in combination with adenovirus mediated mouse insulin-like growth factor 1 (Adv-mIGF-1) gene on T1D in non-obese diabetes (NOD) mice. To simultaneously restore the proportion of Th cells and block the interaction of B cells as well as mediate T cell populations, the NOD model mice were randomly assigned to four groups received the saline, anti-CD20/CD3 bsAb and Adv-mIGF-1 gene alone or combination, respectively. After 16-consecutive weeks intervention, the ELISA, RT-PCR, western blot and histopathological analysis were performed to assess the pancreatic tissues and serum samples to evaluate the treatment effects. Chronic treatment of combination therapy improved T1D morbidity by improving the compartment and function of the CD4⁺Foxp3⁺ Tregs, reversing the secretion of insulin, controlling the blood glucose levels (BGLs) and alleviating insulitis as well as cell apoptosis in the NOD model mice. Moreover, current combination therapy also accelerated the proliferation and differentiation of pancreatic β cells via suppressing the apoptosis-related factors, including caspase-3, caspase-8 and Fas, and activating the Bcl-2-related anti-apoptotic pathway. Furthermore, the cytokeratin-19 (CK-19) and pancreatic duodenal homoplasmic box-1 (PDX-1), as two important stem cell markers of pancreas were both significantly improved by treatment of combination therapy. On conclusions, chronic treatment of anti-CD20/CD3 bsAb in combination with Adv-mIGF-1 gene exerts synergistic protection on T1D in the NOD mice.

A human STAT3 gain-of-function variant confers T cell dysregulation without predominant Treg dysfunction in mice

Primary immune regulatory disorders (PIRD) represent a group of disorders characterized by immune dysregulation, presenting with a wide range of clinical disease, including autoimmunity, autoinflammation, or lymphoproliferation. Autosomal dominant germline gain-of-function (GOF) variants in STAT3 result in a PIRD with a broad clinical spectrum. Studies in patients have documented a decreased frequency of FOXP3+ Tregs and an increased frequency of Th17 cells in some patients with active disease. However, the mechanisms of disease pathogenesis in STAT3 GOF syndrome remain largely unknown, and treatment is challenging. We developed a knock-in mouse model harboring a de novo pathogenic human STAT3 variant (p.G421R) and found these mice developed T cell dysregulation, lymphoproliferation, and CD4+ Th1 cell skewing. Surprisingly, Treg numbers, phenotype, and function remained largely intact; however, mice had a selective deficiency in the generation of iTregs. In parallel, we performed single-cell RNA-Seq on T cells from STAT3 GOF patients. We demonstrate only minor changes in the Treg transcriptional signature and an expanded, effector CD8+ T cell population. Together, these findings suggest that Tregs are not the primary driver of disease and highlight the importance of preclinical models in the study of disease mechanisms in rare PIRD.

IL-2-mTORC1 signaling coordinates the STAT1/T-bet axis to ensure Th1 cell differentiation and anti-bacterial immune response in fish

Utilization of specialized Th1 cells to resist intracellular pathogenic infection represents an important innovation of adaptive immunity. Although transcriptional evidence indicates the potential presence of Th1-like cells in some fish species, the existence of CD3+CD4+IFN-γ+ T cells, their detailed functions, and the mechanism determining their differentiation in these early vertebrates remain unclear. In the present study, we identified a population of CD3+CD4-1+IFN-γ+ (Th1) cells in Nile tilapia upon T-cell activation in vitro or Edwardsiella piscicida infection in vivo. By depleting CD4-1+ T cells or blocking IFN-γ, Th1 cells and their produced IFN-γ were found to be essential for tilapia to activate macrophages and resist the E. piscicida infection. Mechanistically, activated T cells of tilapia produce IL-2, which enhances the STAT5 and mTORC1 signaling that in turn trigger the STAT1/T-bet axis-controlled IFN-γ transcription and Th1 cell development. Additionally, mTORC1 regulates the differentiation of these cells by promoting the proliferation of CD3+CD4-1+ T cells. Moreover, IFN-γ binds to its receptors IFNγR1 and IFNγR2 and further initiates a STAT1/T-bet axis-mediated positive feedback loop to stabilize the Th1 cell polarization in tilapia. These findings demonstrate that, prior to the emergence of tetrapods, the bony fish Nile tilapia had already evolved Th1 cells to fight intracellular bacterial infection, and support the notion that IL-2-mTORC1 signaling coordinates the STAT1/T-bet axis to determine Th1 cell fate, which is an ancient mechanism that has been programmed early during vertebrate evolution. Our study is expected to provide novel perspectives into the evolution of adaptive immunity.

IL-27 shapes the immune properties of human astrocytes and their impact on encountered human T lymphocytes

Background

Interleukin-27 (IL-27) can trigger both pro- and anti-inflammatory responses. This cytokine is elevated in the central nervous system (CNS) of multiple sclerosis (MS) patients, but how it influences neuroinflammatory processes remains unclear. As astrocytes express the receptor for IL-27, we sought to determine how these glial cells respond to this cytokine and whether such exposure alters their interactions with infiltrating activated T lymphocytes. To determine whether inflammation shapes the impact of IL-27, we compared the effects of this cytokine in non-inflamed and inflamed conditions induced by an IL-1β exposure.

Main body

Transcriptomic analysis of IL-27-exposed human astrocytes showed an upregulation of multiple immune genes. Human astrocytes increased the secretion of chemokines (CXCL9, CXCL10, and CXCL11) and the surface expression of proteins (PD-L1, HLA-E, and ICAM-1) following IL-27 exposure. To assess whether exposure of astrocytes to IL-27 influences the profile of activated T lymphocytes infiltrating the CNS, we used an astrocyte/T lymphocyte co-culture model. Activated human CD4⁺ or CD8⁺ T lymphocytes were co-cultured with astrocytes that have been either untreated or pre-exposed to IL‑27 or IL-1β. After 24 h, we analyzed T lymphocytes by flow cytometry for transcription factors and immune molecules. The contact with IL-27-exposed astrocytes increased the percentages of T-bet, Eomes, CD95, IL-18Rα, ICAM-1, and PD-L1 expressing CD4⁺ and CD8⁺ T lymphocytes and reduced the proportion of CXCR3-positive CD8⁺ T lymphocytes. Human CD8⁺ T lymphocytes co-cultured with human IL-27-treated astrocytes exhibited higher motility than when in contact with untreated astrocytes. These results suggested a preponderance of kinapse-like over synapse-like interactions between CD8⁺ T lymphocytes and IL-27-treated astrocytes. Finally, CD8⁺ T lymphocytes from MS patients showed higher motility in contact with IL-27-exposed astrocytes compared to healthy donors’ cells.

Conclusion

Our results establish that IL-27 alters the immune functions of human astrocytes and shapes the profile and motility of encountered T lymphocytes, especially CD8⁺ T lymphocytes from MS patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02572-1.

Systemic IL-27 administration prevents abscess formation and osteolysis via local neutrophil recruitment and activation

Interleukin-27 is a pleiotropic cytokine whose functions during bacterial infections remain controversial, and its role in patients with S. aureus osteomyelitis is unknown. To address this knowledge gap, we completed a clinical study and observed elevated serum IL-27 levels (20-fold higher, P < 0.05) in patients compared with healthy controls. Remarkably, IL-27 serum levels were 60-fold higher in patients immediately following septic death than in uninfected patients (P < 0.05), suggesting a pathogenic role of IL-27. To test this hypothesis, we evaluated S. aureus osteomyelitis in WT and IL-27Rα-/- mice with and without exogenous IL-27 induction by intramuscular injection of rAAV-IL-27p28 or rAAV-GFP, respectively. We found that IL-27 was induced at the surgical site within 1 day of S. aureus infection of bone and was expressed by M0, M1 and M2 macrophages and osteoblasts but not by osteoclasts. Unexpectedly, exogenous IL-27p28 (~2 ng·mL-1 in serum) delivery ameliorated soft tissue abscesses and peri-implant bone loss during infection, accompanied by enhanced local IL-27 expression, significant accumulation of RORγt+ neutrophils at the infection site, a decrease in RANK+ cells, and compromised osteoclast formation. These effects were not observed in IL-27Rα-/- mice compared with WT mice, suggesting that IL-27 is dispensable for immunity but mediates redundant immune and bone cell functions during infection. In vitro studies and bulk RNA-seq of infected tibiae showed that IL-27 increased nos1, nos2, il17a, il17f, and rorc expression but did not directly stimulate chemotaxis. Collectively, these results identify a novel phenomenon of IL-27 expression by osteoblasts immediately following S. aureus infection of bone and suggest a protective role of systemic IL-27 in osteomyelitis.

Skin Injury Activates a Rapid TRPV1-Dependent Antiviral Protein Response

The skin serves as the interface between the body and the environment and plays a fundamental role in innate antimicrobial host immunity. Antiviral proteins (AVPs) are part of the innate host defense system and provide protection against viral pathogens. How breach of the skin barrier influences innate AVP production remains largely unknown. In this study, we characterized the induction and regulation of AVPs after skin injury and identified a key role of TRPV1 in this process. Transcriptional and phenotypic profiling of cutaneous wounds revealed that skin injury induces high levels of AVPs in both mice and humans. Remarkably, pharmacologic and genetic ablation of TRPV1-mediated nociception abrogated the induction of AVPs, including Oas2, Oasl2, and Isg15 after skin injury in mice. Conversely, stimulation of TRPV1 nociceptors was sufficient to induce AVP production involving the CD301b+ cells‒IL-27‒mediated signaling pathway. Using IL-27 receptor‒knockout mice, we show that IL-27 signaling is required in the induction of AVPs after skin injury. Finally, loss of TRPV1 signaling leads to increased viral infectivity of herpes simplex virus. Together, our data indicate that TRPV1 signaling ensures skin antiviral competence on wounding.

Structure of the IL-27 quaternary receptor signaling complex

Interleukin 27 (IL-27) is a heterodimeric cytokine that functions to constrain T cell-mediated inflammation and plays an important role in immune homeostasis. Binding of IL-27 to cell surface receptors, IL-27Rα and gp130, results in activation of receptor-associated Janus Kinases and nuclear translocation of Signal Transducer and Activator of Transcription 1 (STAT1) and STAT3 transcription factors. Despite the emerging therapeutic importance of this cytokine axis in cancer and autoimmunity, a molecular blueprint of the IL-27 receptor signaling complex, and its relation to other gp130/IL-12 family cytokines, is currently unclear. We used cryogenic-electron microscopy to determine the quaternary structure of IL-27, composed of p28 and Epstein-Barr Virus-Induced 3 (Ebi3) subunits, bound to receptors, IL-27Rα and gp130. The resulting 3.47 Å resolution structure revealed a three-site assembly mechanism nucleated by the central p28 subunit of the cytokine. The overall topology and molecular details of this binding are reminiscent of IL-6 but distinct from related heterodimeric cytokines IL-12 and IL-23. These results indicate distinct receptor assembly mechanisms used by heterodimeric cytokines with important consequences for targeted agonism and antagonism of IL-27 signaling.

Antiviral Activities of Interleukin-27: A Partner for Interferons?

Emergence of new, pandemic-level viral threats has brought to the forefront the importance of viral immunology and continued improvement of antiviral therapies. Interleukin-27 (IL-27) is a pleiotropic cytokine that regulates both innate and adaptive immune responses. Accumulating evidence has revealed potent antiviral activities of IL-27 against numerous viruses, including HIV, influenza, HBV and more. IL-27 contributes to the immune response against viruses indirectly by increasing production of interferons (IFNs) which have various antiviral effects. Additionally, IL-27 can directly interfere with viral infection both by acting similarly to an IFN itself and by modulating the differentiation and function of various immune cells. This review discusses the IFN-dependent and IFN-independent antiviral mechanisms of IL-27 and highlights the potential of IL-27 as a therapeutic cytokine for viral infection.

IL-27 Induces CCL5 Production by T Lymphocytes, Which Contributes to Antitumor Activity

IL-27 is a pleiotropic cytokine that exhibits stimulatory/regulatory functions on multiple lineages of immune cells including T lymphocytes. In this study, we demonstrate that IL-27 directly induces CCL5 production by T lymphocytes, particularly CD8⁺ T cells in vitro and in vivo. IL-27-induced CCL5 production is IL-27R-dependent. In CD4⁺ T cells, IL-27-induced CCL5 production was primarily dependent on Stat1 activation, whereas in CD8⁺ T cells, Stat1 deficiency does not abrogate CCL5 induction. A chromatin immunoprecipitation assay revealed that in the CCL5 promoter region, both putative Stat3 binding sites exhibit significant binding to Stat3, whereas only one out of four Stat1 binding sites displays moderate binding to Stat1. In tumor-bearing mice, IL-27 induced dramatic production of CCL5 in tumor-infiltrating T cells. IL-27-induced CCL5 appears to contribute to an IL-27-mediated antitumor effect. This is signified by diminished tumor inhibition in anti-CCL5- and IL-27-treated mice. Additionally, intratumor delivery of CCL5 mRNA using lipid nanoparticles significantly inhibited tumor growth. Thus, IL-27 induces robust CCL5 production by T cells, which contributes to antitumor activity.

Molecular Signature of Neuroinflammation Induced in Cytokine-Stimulated Human Cortical Spheroids

Crucial in the pathogenesis of neurodegenerative diseases is the process of neuroinflammation that is often linked to the pro-inflammatory cytokines Tumor necrosis factor alpha (TNFα) and Interleukin-1beta (IL-1β). Human cortical spheroids (hCSs) constitute a valuable tool to study the molecular mechanisms underlying neurological diseases in a complex three-dimensional context. We recently designed a protocol to generate hCSs comprising all major brain cell types. Here we stimulate these hCSs for three time periods with TNFα and with IL-1β. Transcriptomic analysis reveals that the main process induced in the TNFα- as well as in the IL-1β-stimulated hCSs is neuroinflammation. Central in the neuroinflammatory response are endothelial cells, microglia and astrocytes, and dysregulated genes encoding cytokines, chemokines and their receptors, and downstream NFκB- and STAT-pathway components. Furthermore, we observe sets of neuroinflammation-related genes that are specifically modulated in the TNFα-stimulated and in the IL-1β-stimulated hCSs. Together, our results help to molecularly understand human neuroinflammation and thus a key mechanism of neurodegeneration.

The Host Peritoneal Cavity Harbors Prominent Memory Th2 and Early Recall Responses to an Intestinal Nematode

Intestinal parasitic nematodes affect a quarter of the world’s population, typically eliciting prominent effector Th2-driven host immune responses. As not all infected hosts develop protection against reinfection, our current understanding of nematode-induced memory Th2 responses remains limited. Here, we investigated the activation of memory Th2 cells and the mechanisms driving early recall responses to the enteric nematode Heligmosomoides polygyrus in mice. We show that nematode-cured mice harbor memory Th2 cells in lymphoid and non-lymphoid organs with distinct transcriptional profiles, expressing recirculation markers like CCR7 and CD62-L in the mesenteric lymph nodes (mLN), and costimulatory markers like Ox40, as well as tissue homing and activation markers like CCR2, CD69 and CD40L in the gut and peritoneal cavity (PEC). While memory Th2 cells persist systemically in both lymphoid and non-lymphoid tissues following cure of infection, peritoneal memory Th2 cells in particular displayed an initial prominent expansion and strong parasite-specific Th2 responses during early recall responses to a challenge nematode infection. This effect was paralleled by a significant influx of dendritic cells (DC) and eosinophils, both also appearing exclusively in the peritoneal cavity of reinfected mice. In addition, we show that within the peritoneal membrane lined by peritoneal mesothelial cells (PeM), the gene expression levels of cell adhesion markers VCAM-1 and ICAM-1 decrease significantly in response to a secondary infection. Overall, our findings indicate that the host peritoneal cavity in particular harbors prominent memory Th2 cells and appears to respond directly to H. polygyrus by an early recall response via differential regulation of cell adhesion markers, marking the peritoneal cavity an important site for host immune responses to an enteric pathogen.

IL-27 Modulates the Cytokine Secretion in the T Cell-Osteoclast Crosstalk During HIV Infection

In People with HIV (PWH), chronic immune activation and systemic inflammation are associated with increased risk to develop comorbidities including bone loss. Numerous cells of the immune system, namely, T cells are involved in the regulation of the bone homeostasis and osteoclasts (OCs) activity. IL-27, a cytokine that belongs to the IL-12 family can regulate the secretion of pro- and anti-inflammatory cytokines by T cells, however its role in the setting of HIV is largely unknown. In the present study, we determined the impact of OCs in T cell secretion of cytokines and whether IL-27 can regulate this function. We found that the presence of OCs in the T cell cultures significantly enhanced secretion of IFNγ, TNFα, IL-17, RANKL, and IL-10 in both PWH and healthy controls. In PWH, IL-27 inhibited IL-17 secretion and downregulated surface expression of RANKL in CD4 T cells. All together these results suggest that in the context of HIV infection IL-27 may favor IFNγ and TNFα secretion at the sites of bone remodeling.

Interleukin 27 Signaling in Rheumatoid Arthritis Patients: Good or Evil?

The occurrence and development of rheumatoid arthritis (RA) is regulated by numerous cytokines. Interleukin 27 (IL-27) is a soluble cytokine that exerts biological effects by regulating the Janus tyrosine kinase (JAK)/signal transducer and activator of the transcription (STAT) signaling pathway via the IL-27 receptor. IL-27 is known for its pleiotropic roles in modulating inflammatory responses. Previous studies found that IL-27 levels are elevated in RA blood, synovial fluid, and rheumatoid nodules. Cellular and animal experiments indicated that IL-27 exerts multiple regulatory functions in RA patients via different mechanisms. IL-27 inhibits ectopic-like structure (ELS) formation and CD4⁺ T helper type 2 (Th2) cell, CD4⁺ T helper type 17 (Th17) cell, and osteoclast differentiation in RA, contributing to alleviating RA. However, IL-27 promotes Th1 cell differentiation, which may exacerbate RA synovitis. Moreover, IL-27 also acts on RA synovial fibroblasts (RA-FLSs) and regulatory T cells (Tregs), but some of its functions are unclear. There is currently insufficient evidence to determine whether IL-27 promotes or relieves RA. Targeting IL-27 signaling in RA treatment should be deliberate based on current knowledge.

Transcription factors and regulators pathway-focused genes expression analysis in patients with different forms of thyroid pathology

BACKGROUND

Autoimmune thyroiditis (AIT) is a T cell-mediated organ-specific disorder and transcription factors have a critical role in the regulation of immune responses, especially in the fate of T-helper cells.

OBJECTIVE

This study aims to investigate changes in the gene expression profile of transcription factors and regulators in patients with different forms of thyroid pathology Methods. We used the pathway-specific real-time PCR array (Neurotrophins and Receptors RT2 Profiler PCR Array, QIAGEN, Germany) to identify and verify transcription factors and regulators pathway-focused genes expression in peripheral white blood cells of patients with postoperative hypothyroidism, hypothyroidism as a result of AIT and AIT with elevated serum an anti-thyroglobulin (anti-Tg) and anti-thyroid peroxidase (anti-TPO) antibodies.

RESULTS

It was shown that in patients with postoperative hypothyroidism FOS, NR1I2, STAT4, and TP53 significantly increased their expression whereas the expression of STAT1, STAT2, and STAT3 decreased. In patients with hypothyroidism as a result of AIT, we have found increased expression of NR1I2, STAT2, and STAT3. In contrast, the expression of STAT1 and TP53 decreased. FOS and STAT4 mRNAs did not change their expression. In patients with AIT and elevated serum anti-Tg and anti-TPO antibodies, the expression of FOS and NR1I2 reduced whereas the mRNA level of STAT3 increased. STAT1, STAT2, and STAT4 mRNAs did not change their expression. MYC did not change its expression in all groups of patients.

CONCLUSIONS

The results of this study demonstrate that autoimmune thyroiditis and hypothyroidism affect the mRNA-level expression of transcription factors and regulators genes in a gene-specific manner and that these changes to genes expression can be among the triggers of autoimmune inflammation progression in the thyroid gland.

Synergistic Effects of Toll-Like Receptor 1/2 and Toll-Like Receptor 3 Signaling Triggering Interleukin 27 Gene Expression in Chikungunya Virus-Infected Macrophages

Chikungunya virus (CHIKV) is the etiological agent of chikungunya fever (CHIKF), a self-limiting disease characterized by myalgia and severe acute or chronic arthralgia. CHIKF is associated with immunopathology and high levels of pro-inflammatory factors. CHIKV is known to have a wide range of tropism in human cell types, including keratinocytes, fibroblasts, endothelial cells, monocytes, and macrophages. Previously, we reported that CHIKV-infected monocytes-derived macrophages (MDMs) express high levels of interleukin 27 (IL27), a heterodimeric cytokine consisting of IL27p28 and EBI3 subunits, that triggers JAK-STAT signaling and promotes pro-inflammatory and antiviral response, in interferon (IFN)-independent manner. Based on the transcriptomic analysis, we now report that induction of IL27-dependent pro-inflammatory and antiviral response in CHIKV-infected MDMs relies on two signaling pathways: an early signal dependent on recognition of CHIKV-PAMPs by TLR1/2-MyD88 to activate NF-κB-complex that induces the expression of EBI3 mRNA; and second signaling dependent on the recognition of intermediates of CHIKV replication (such as dsRNA) by TLR3-TRIF, to activate IRF1 and the induction of IL27p28 mRNA expression. Both signaling pathways were required to produce a functional IL27 protein involved in the induction of ISGs, including antiviral proteins, cytokines, CC- and CXC- chemokines in an IFN-independent manner in MDMs. Furthermore, we reported that activation of TLR4 by LPS, both in human MDMs and murine BMDM, results in the induction of both subunits of IL27 that trigger strong IL27-dependent pro-inflammatory and antiviral response independent of IFNs signaling. Our findings are a significant contribution to the understanding of molecular and cellular mechanisms of CHIKV infection.

TNF Receptor-Associated Factor 5 Limits IL-27 Receptor Signaling in CD4+ T Lymphocytes

TNF receptor-associated factor 5 (TRAF5) restrains early signaling activity of the IL-6 receptor in naive CD4⁺ T cells by interacting with the shared gp130 chain, although TRAF5 was initially discovered as a cytoplasmic adaptor protein to activate signaling mediated by TNF receptor family molecules. This leads to the question of whether TRAF5 limits signaling via the receptor for IL-27, which is composed of gp130 and WSX-1. The aim of this study is to clarify the role of TRAF5 in IL-27 receptor signaling and to understand the differential role of TRAF5 on cytokine receptor signaling. We found that Traf5 ^-/- CD4⁺ T cells displayed significantly higher levels of phosphorylated STAT1 and STAT-regulated genes Socs3 and Tbx21, as early as 1 h after IL-27 exposure when compared with Traf5 ^+/+ CD4⁺ T cells. Upon IL-27 and TCR signals, the Traf5 deficiency significantly increased the induction of IL-10 and promoted the proliferation of CD4⁺ T cells. Traf5 ^-/- mice injected with IL-27 displayed significantly enhanced delayed-type hypersensitivity responses, demonstrating that TRAF5 works as a negative regulator for IL-27 receptor signaling. In contrast, IL-2 and proliferation mediated by glucocorticoid-induced TNF receptor-related protein (GITR) and TCR signals were significantly decreased in Traf5 ^-/- CD4⁺ T cells, confirming that TRAF5 works as a positive regulator for cosignaling via GITR. Collectively, our results demonstrate that TRAF5 reciprocally controls signals mediated by the IL-27 receptor and GITR in CD4⁺ T cells and suggest that the regulatory activity of TRAF5 in gp130 is distinct from that in TNF receptor family molecules in a T cell.

IL-27 mediates anti-inflammatory effect in cigarette smoke induced emphysema by negatively regulating IFN-γ producing cytotoxic CD8+ T cells in mice

Chronic airway inflammation mediated by CD8+ T lymphocytes contributes to the pathogenesis of Chronic obstructive pulmonary disease (COPD). Deciphering the fingerprint of the chronic inflammation orchestrated by CD8+ T cells may allow the development of novel approaches to COPD management. Here, the expression of IL-27 and IFN-γ+ CD8+ Tc1 cells were evaluated in patients with COPD and in cigarette smoke-exposed mice. The production of IL-27 by marrow-derived dendritic cells (mDCs) in response to cigarette smoke extract (CSE) was assessed. The role of IL-27 in IFN-γ+ CD8+ Tc1 cells was explored. We demonstrated that elevated IL-27 was accompanied by an exaggerated IFN-γ+ CD8+ Tc1 response in a smoking mouse model of emphysema. We noted that lung dendritic cells were one of the main sources of IL-27 during chronic cigarette smoke exposure. Moreover, CSE directly induced the production of IL-27 by mDCs in vitro. IL-27 negatively regulated the differentiation of IFN-γ+ CD8+ Tc1 cells isolated from cigarette smoke-exposed mice in a STAT1- and STAT3-independent manner. Systemic administration of recombinant IL-27 attenuated IFN-γ+ CD8+ Tc1 response in the late phase of cigarette smoke exposure. Our results uncovered that IL-27 negatively regulates IFN-γ+ CD8+ Tc1 response in the late stage of chronic cigarette smoke exposure, which may provide a new strategy for the anti-inflammatory treatment of smoking-related COPD/emphysema.

IL-27 induces IFN/STAT1-dependent genes and enhances function of TIGIT+ HIVGag-specific T cells

HIV-specific T cells have diminished effector function and fail to control/eliminate the virus. IL-27, a member of the IL-6/IL-12 cytokine superfamily has been shown to inhibit HIV replication. However, whether or not IL-27 can enhance HIV-specific T cell function is largely unknown. In the present manuscript, we investigated the role of IL-27 signaling in human T cells by evaluating the global transcriptional changes related to the function of HIV-specific T cells. We found that T cells from people living with HIV (PLWH), expressed higher levels of STAT1 leading to enhanced STAT1 activation upon IL-27 stimulation. Observed IL-27 induced transcriptional changes were associated with IFN/STAT1-dependent pathways in CD4 and CD8 T cells. Importantly, IL-27 dependent modulation of T-bet expression promoted IFNγ secretion by TIGIT+HIVGag-specific T cells. This new immunomodulatory effect of IL-27 on HIV-specific T cell function suggests its potential therapeutic use in cure strategies.

Interleukin-27 in Tuberculosis: A Sheep in Wolf’s Clothing?

In tuberculosis (TB), protective inflammatory immune responses and the pathological sequelae of chronic inflammation significantly depend on a timely balance of cytokine expression. In contrast to other anti-inflammatory cytokines, interleukin (IL)-27 has fundamental effects in experimental Mycobacterium tuberculosis (Mtb) infection: the absence of IL-27-mediated signalling promotes a better control of mycobacterial growth on the one hand side but also leads to a chronic hyperinflammation and immunopathology later during infection. Hence, in the context of novel host-directed therapeutic approaches and vaccination strategies for the management of TB, the timely restricted blockade of IL-27 signalling may represent an advanced treatment option. In contrast, administration of IL-27 itself may allow to treat the immunopathological consequences of chronic TB. In both cases, a better knowledge of the cell type-specific and kinetic effects of IL-27 after Mtb infection is essential. This review summarizes IL-27-mediated mechanisms affecting protection and immunopathology in TB and discusses possible therapeutic applications.

IL-27 Mediates Th1 Cells Infiltration in Fetal Membranes in Preterm Labor

The objective of this study is to investigate the effect of IL-27 on Th1 cells infiltration in human fetal membranes (FMs) in preterm labor (PL). The expression of Th1 cells specific transcription factor (T-bet), Th1 cells infiltration related molecules (CXCL9, CXCL10, CXCL11, and ICAM-1), and IL-27 receptor α subunit (IL-27Rα) was compared in human FMs from pregnant women in PL group and term labor (TL) group. In vitro, rhIL-27 was added to the culture medium of amniotic epithelial cells (WISH cells) to detect the expression of CXCL9, CXCL10, CXCL11, and ICAM-1. Furthermore, the underlying signaling pathway was detected by single-sample gene set enrichment analysis and western blot analysis. The expression of T-bet and CXCL9, CXCL10, CXCL11, and ICAM-1 as well as IL-27Rα was higher in human FMs from PL group than TL group. In vitro, rhIL-27 could upregulate the expression of CXCL9, CXCL10, CXCL11, and ICAM-1 in WISH cells. Using gene-set enrichment analysis of FMs, JAK/STAT signaling pathway was found to be activated by IL-27 signaling in PL. Using western blot analysis, JAK2/STAT1/STAT3 signaling pathway was confirmed to be enhanced in rhIL-27 treated WISH cells. In addition, AG490 (JAK2 inhibitor) could inhibit the secretion of CXCL9, CXCL10, and CXCL11 in WISH cells stimulated by rhIL-27. Our results suggested that IL-27 may promote Th1 cells infiltration in human FMs in PL, by promoting the expression of CXCL9, CXCL10, and CXCL11 at least partly through JAK2/STAT1/STAT3 signaling pathway.

A novel cytokine consisting of the p40 and EBI3 subunits suppresses experimental autoimmune arthritis via reciprocal regulation of Th17 and Treg cells

OBJECTIVE

The interleukin (IL)-12 cytokine family is closely related to the development of T helper cells, which are responsible for autoimmune disease enhancement or suppression. IL-12 family members are generally heterodimers and share three α-subunits (p35, p19, and p28) and two β-subunits (p40 and EBI3). However, a β-sheet p40 homodimer has been shown to exist and antagonize IL-12 and IL-23 signaling ¹. Therefore, we assumed the existence of a p40-EBI3 heterodimer in nature and sought to investigate its role in immune regulation.

METHODS

The presence of the p40-EBI3 heterodimer was confirmed by ELISA, immunoprecipitation, and western blotting. A p40-EBI3 vector and p40-EBI3-Fc protein were synthesized to confirm the immunological role of this protein in mice with collagen-induced arthritis (CIA). The anti-inflammatory effects of p40-EBI3 were analyzed with regard to clinical, histological, and immune cell-regulating features in mice with CIA.

RESULTS

Clinical arthritis scores and the expression levels of proinflammatory cytokines (e.g., IL-17, IL-1β, IL-6, and TNF-α) were significantly attenuated in p40-EBI3-overexpressing and p40-EBI3-Fc-treated mice with CIA compared to vehicle-treated mice with CIA. Structural joint damage and vessel formation-related gene expression were also reduced by p40-EBI3 heterodimer treatment. In vitro, the p40-EBI3-Fc protein significantly suppressed the differentiation of Th17 cells and reciprocally induced CD4⁺CD25⁺Foxp3⁺ (regulatory T) cells. p40-EBI3 also inhibited osteoclast formation in a concentration-dependent manner.

CONCLUSION

In this study, p40-EBI3 ameliorated proinflammatory conditions both in vivo and in vitro. We propose that p40-EBI3 is a novel anti-inflammatory cytokine involved in suppressing the immune response through the expansion of Treg cells and suppression of Th17 cells and osteoclastogenesis.

The Role of IL-27 in the Systemic Inflammatory Response That Accompanies Preterm Labour

This study aimed to investigate whether interleukin-27 (IL-27) activates maternal peripheral blood mononuclear cells (PBMCs) and induces inflammatory responses in amniotic epithelial cells in preterm labour (PL). The expression of IL-27p28, EBI3 and IL-27Rα was compared in maternal PBMCs of the PL, term labour (TL) and term not in labour (TNL) groups. The relationship between IL-27 and molecules associated with PBMC activation was investigated using bioinformatic and quantitative reverse transcription polymerase chain reaction (qRT-PCR) analyses. We investigated the inflammatory effects of IL-27 in PBMCs and its underlying mechanisms in vitro. In addition, we treated amniotic epithelial cells (WISH cells) with a PBMC-conditioned medium to identify the inflammatory effects of IL-27-treated PBMCs in amniotic epithelial cells. The expression of IL-27p28 and IL-27Rα in PBMCs of the PL group was higher than that in the TL/TNL groups. Bioinformatic analysis revealed that IL-27 was positively correlated with IFNG, IL6, IL1β, CXCL10 and ICAM1 in the whole blood samples of pregnant women in the PL group, which was confirmed using qRT-PCR. Furthermore, rhIL-27 promoted the expression of Th1 cell-related molecules (T-bet, IFN-γ and ICAM-1) and proinflammatory cytokines (IL-6 and IL-1β) in PBMCs in vitro, which was partially mediated by the JAK2/STAT1 pathway. In addition, it enhanced the expression of IL-27p28, EBI3 and IL-27Rα in PBMCs. Moreover, the expression of IL-6, IL-1β and TNF-α in WISH cells was significantly increased by the conditional medium derived from IL-27-treated PBMCs. IL-27 upregulated the expression of Th1 cell-related molecules and proinflammatory cytokines in PBMCs partially mediated by the JAK2/STAT1 pathway. Inflammatory responses were induced in WISH cells by a conditional medium derived from IL-27-treated PBMCs. Therefore, IL-27 may contribute to PL by promoting inflammation in maternal PBMCs and amniotic epithelial cells.

Cholesterol 25-hydroxylase is a metabolic switch to constrain T cell-mediated inflammation in the skin

Interleukin-27 (IL-27) is an immunoregulatory cytokine whose essential function is to limit immune responses. We found that the gene encoding cholesterol 25-hydroxylase (Ch25h) was induced in CD4+ T cells by IL-27, enhanced by transforming growth factor–β (TGF-β), and antagonized by T-bet. Ch25h catalyzes cholesterol to generate 25-hydroxycholesterol (25OHC), which was subsequently released to the cellular milieu, functioning as a modulator of T cell response. Extracellular 25OHC suppressed cholesterol biosynthesis in T cells, inhibited cell growth, and induced nutrient deprivation cell death without releasing high-mobility group box 1 (HMGB1). This growth inhibitory effect was specific to actively proliferating cells with high cholesterol demand and was reversed when extracellular cholesterol was replenished. Ch25h-expressing CD4+ T cells that received IL-27 and TGF-β signals became refractory to 25OHC-mediated growth inhibition in vitro. Nonetheless, IL-27–treated T cells negatively affected viability of bystander cells in a paracrine manner, but only if the bystander cells were in the early phases of activation. In mouse models of skin inflammation due to autoreactive T cells or chemically induced hypersensitivity, genetic deletion of Ch25h or Il27ra led to worse outcomes. Thus, Ch25h is an immunoregulatory metabolic switch induced by IL-27 and dampens excess bystander T effector expansion in tissues through its metabolite derivative, 25OHC. This study reveals regulation of cholesterol metabolism as a modality for controlling tissue inflammation and thus represents a mechanism underlying T cell immunoregulatory functions.

A Chaperone-Like Role for EBI3 in Collaboration With Calnexin Under Inflammatory Conditions

The interleukin-6 (IL-6)/IL-12 family of cytokines plays critical roles in the induction and regulation of innate and adaptive immune responses. Among the various cytokines, only this family has the unique characteristic of being composed of two distinct subunits, α- and β-subunits, which form a heterodimer with subunits that occur in other cytokines as well. Recently, we found a novel intracellular role for one of the α-subunits, Epstein-Barr virus-induced gene 3 (EBI3), in promoting the proper folding of target proteins and augmenting its expression at the protein level by binding to its target protein and a well-characterized lectin chaperone, calnexin, presumably through enhancing chaperone activity. Because calnexin is ubiquitously and constitutively expressed but EBI3 expression is inducible, these results could open an avenue to establish a new paradigm in which EBI3 plays an important role in further increasing the expression of target molecules at the protein level in collaboration with calnexin under inflammatory conditions. This theory well accounts for the heterodimer formation of EBI3 with p28, and probably with p35 and p19 to produce IL-27, IL-35, and IL-39, respectively. In line with this concept, another β-subunit, p40, plays a critical role in the assembly-induced proper folding of p35 and p19 to produce IL-12 and IL-23, respectively. Thus, chaperone-like activities in proper folding and maturation, which allow the secretion of biologically active heterodimeric cytokines, have recently been highlighted. This review summarizes the current understanding of chaperone-like activities of EBI3 to form heterodimers and other associations together with their possible biological implications.

STAT1 maintains naïve CD8+ T cell quiescence by suppressing the type I IFN-STAT4-mTORC1 signaling axis

Naïve CD8⁺ T cell quiescence is maintained at a steady state. Although this state of quiescence involves various cell-intrinsic and cell-extrinsic regulators, the mechanisms underlying this regulation remain incompletely understood. Here, we found that signal transducer and activator of transcription 1 (STAT1), a key transcription factor downstream of interferon receptor (IFNR) signaling, plays a cell-intrinsic role in maintaining naïve CD8⁺ T cell quiescence. STAT1-deficient mice showed enhanced proliferation of peripheral naïve CD8⁺ T cells, which resulted in an abnormal increase in the number of CD44^hi memory/activated phenotype cells and an enlargement of secondary lymphoid tissues. This phenomenon was not observed in IFNR-deficient mice but was paradoxically dependent on type I interferon and its alternative signaling pathway via the STAT4–RagD–lysosomal mTORC1 axis. Collectively, these findings underline the importance of STAT1 in regulating the homeostasis of peripheral naïve CD8⁺ T cells by suppressing their responsiveness to homeostatic cues at a steady state.

Immunological Determinants of Liver Transplant Outcomes Uncovered by the Rat Model

For many individuals with end-stage liver disease, the only treatment option is liver transplantation. However, liver transplant rejection is observed in 24%-80% of transplant patients and lifelong drug regimens that follow the transplant procedure lead to serious side effects. Furthermore, the pool of donor livers available for transplantation is far less than the demand. Well-characterized and physiologically relevant models of liver transplantation are crucial to a deeper understanding of the cellular processes governing the outcomes of liver transplantation and serve as a platform for testing new therapeutic strategies to enhance graft acceptance. Such a model has been found in the rat transplant model, which has an advantageous size for surgical procedures, similar postoperative immunological progression, and high genome match to the human liver. From rat liver transplant studies published in the last 5 years, it is clear that the rat model serves as a strong platform to elucidate transplant immunological mechanisms. Using the model, we have begun to uncover potential players and possible therapeutic targets to restore liver tolerance and preserve host immunocompetence. Here, we present an overview of recent literature for rat liver transplant models, with an aim to highlight the value of the models and to provide future perspectives on how these models could be further characterized to enhance the overall value of rat models to the field of liver transplantation.

The dual role of IL-27 in CD4+T cells

Interleukin-27 (IL-27), a member of the IL-6/IL-12 family, has diverse regulatory functions in various immune responses, and is recognised as a potent agonist and antagonist of CD4+T cells in different contexts. However, this dual role and underlying mechanisms have not been completely defined. In the present review, we summarise the dual role of IL-27 in CD4+T cells. In particular, we aimed to decipher its mechanism to better understand the context-dependent function of IL-27 in CD4+T cells. Furthermore, we propose a possible mechanism for the dual role of IL-27. This may be helpful for the development of appropriate IL-27 treatments in various clinical settings.

Prognostic value of plasma IL-27 on biological viability of hepatic cystic echinococcosis

OBJECTIVES

To investigate potential biomarkers for distinguishing biological viability of hepatic cystic echinococcosis.

METHODS

Using Luminex assay we measured plasma concentrations of cytokine and chemokine in patients with active and non-active cysts (hepatic cystic echinococcosis (HCE), n = 47) and stable/progressive hepatic alveolar echinococcosis (HAE, n = 38), and in comparable infection-free volunteers (n = 48). Disease progression was staged according to the classification standard.

RESULTS

Compared with healthy controls, enhanced elevation was found of T helper 22 type cytokine interleukin (IL)-22 and chemokines Eotaxin, interferon-γ inducible protein-10, monocyte chemoattractant protein-1, and stromal cell-derived factor-1α concentrations in HAE patients, and IL-22, growth-related oncogene α, monocyte chemoattractant protein-1, regulated on activation normal T-expressed and secreted, and stromal cell-derived factor-1α concentrations in HCE patients (P < 0.05-0.001). For HCE patients, only IL-27 concentrations in non-active HCE were significantly lower than in active HCE. In logistic regression analysis, IL-27 <20.79 pg/mL was an independent risk factor for HCE biological viability with receiver operating characteristic analysis at a 44.23 pg/mL cut-off resulting in 0.72 area under the curve.

CONCLUSIONS

Our findings correlate multiple cytokine and chemokine secretion patterns in HAE and HCE patients with different disease progression stages. IL-27 could serve as a referring biomarker for distinguishing HCE biological viability and provide a preliminary foundation for clinical decision-making.

Immune exhaustion in chronic Chagas disease: Pro-inflammatory and immunomodulatory action of IL-27 in vitro

In chronic Chagas disease, Trypanosoma cruzi-specific T-cell function decreases over time, and alterations in the homeostatic IL-7/IL-7R axis are evident, consistent with a process of immune exhaustion. IL-27 is an important immunoregulatory cytokine that shares T-cell signaling with IL-7 and other cytokines of the IL-12 family and might be involved in the transcriptional regulation of T-cell function. Here, we evaluated the expression and function of IL-27R in antigen-experienced T cells from subjects with chronic Chagas disease and assessed whether in vitro treatment with IL-27 and IL-7 might improve T. cruzi-specific polyfunctional T-cell responses. In vitro exposure of PBMCs to T. cruzi induced a downregulation of IL-27R in CD4+ T cells and an upregulation in CD8+ T cells in subjects without heart disease, while IL-27R expression remained unaltered in subjects with more severe clinical stages. The modulation of IL-27R was associated with functional signaling through STAT3 and STAT5 and induction of the downstream genes TBX21, EOMES and CXCL9 in response to IL-27. In vitro treatment of PBMCs with IL-27 and IL-7 improved monofunctional and polyfunctional Th1 responses, accompanied by the induction of IL-10 and Bcl-2 expression in subjects without heart disease but did not improve those in subjects with cardiomyopathy. Our findings support the process of desensitization of the IL-27/IL-27R pathway along with disease severity and that the pro-inflammatory and immunomodulatory mechanisms of IL-27 might be interconnected.

The Role of Interleukin-27 in Atherosclerosis: A Contemporary Review

Atherosclerosis is a chronic inflammation characterized by an imbalance between inhibitors and stimulators of the inflammatory system that leads to the formation of atherosclerotic plaques in the vessel walls. Interleukin (IL)-27 is one of the recently discovered cytokines that have an immunomodulatory role in autoimmune and inflammatory diseases. However, the definite role of IL-27 in the pathogenesis of atherosclerosis remains unclear. Recent studies on cardiomyocytes and vascular endothelium have demonstrated mechanisms through which IL-27 could potentially modulate atherosclerosis. Upregulation of the IL-27 receptor was also observed in the atherosclerotic plaques. In addition, circulatory IL-27 levels were increased in patients with acute coronary syndrome and myocardial infarction. A regenerative, neovascularization, and cardioprotective role of IL-27 has also been implicated. Future studies are warranted to elucidate the biologic function and clinical significance of IL-27 in atherosclerosis.