Treatment with IL-27 attenuates experimental colitis through the suppression of the development of IL-17-producing T helper cells

IL-12 family cytokines and autoimmune diseases: A potential therapeutic target?

In recent years, the discovery of IL-12 family cytokines, which includes IL-12, IL-23, IL-27, IL-35, and IL-39, whose biological functions directly or indirectly affect various autoimmune diseases. In autoimmune diseases, IL-12 family cytokines are aberrantly expressed to varying degrees. These cytokines utilize shared subunits to influence T-cell activation and differentiation, thereby regulating the balance of T-cell subsets, which profoundly impacts the onset and progression of autoimmune diseases. In such conditions, IL-12 family members are aberrantly expressed to varying degrees. By exploring their immunomodulatory functions, researchers have identified varying therapeutic potentials for each member. This review examines the physiological functions of the major IL-12 family members and their interactions, discusses their roles in several autoimmune diseases, and summarizes the progress of clinical studies involving monoclonal antibodies targeting IL-12 and IL-23 subunits currently available for treatment.

Interleukin-27 and Autoimmune Disorders: A Compressive Review of Immunological Functions

Autoimmune disorders (ADs) pose significant health and economic burdens globally, characterized by the body's immune system mistakenly attacking its own tissues. While the precise mechanisms driving their development remain elusive, a combination of genetic predisposition(s) and environmental triggers is implicated. Interleukin-27 (IL-27), among numerous cytokines involved, has emerged as a key regulator, exhibiting dual roles in immune modulation. This review delves into the molecular structure and signaling mechanisms of IL-27, highlighting its diverse effects on various immune cells. Additionally, it explores the involvement of IL-27 in autoimmune diseases, such as multiple sclerosis (MS) and rheumatoid arthritis (RA), offering insights into its potential therapeutic implications. Moreover, its involvement in autoimmune diseases like type 1 diabetes (T1D), inflammatory bowel disease (IBD), myasthenia gravis (MG), Sjögren's syndrome (SS), and Guillain-Barré syndrome (GBS) is multifaceted, with potential diagnostic and therapeutic implications across these conditions. Further research is essential to fully understand IL-27's mechanisms of action and therapeutic potential in autoimmune diseases.

Synthetic Biology-Driven Microbial Therapeutics for Disease Treatment

The human microbiome, consisting of microorganisms that coexist symbiotically with the body, impacts health from birth. Alterations in gut microbiota driven by factors such as diet and medication can contribute to diseases beyond the gut. Synthetic biology has paved the way for engineered microbial therapeutics, presenting promising treatments for a variety of conditions. Using genetically encoded biosensors and dynamic regulatory tools, engineered microbes can produce and deliver therapeutic agents, detect biomarkers, and manage diseases. This review organizes engineered microbial therapeutics by disease type, emphasizing innovative strategies and recent advancements. The scope of diseases includes gastrointestinal disorders, cancers, metabolic diseases, infections, and other ailments. Synthetic biology facilitates precise targeting and regulation, improving the efficacy and safety of these therapies. With promising results in animal models, engineered microbial therapeutics provide a novel alternative to traditional treatments, heralding a transformative era in diagnostics and treatment for numerous diseases.

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.

Deletion of IL-27p28 induces CD8 T cell immunity against colorectal tumorigenesis

Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide, characterized by molecular and clinical heterogeneity. Interleukin (IL)-27, a heterodimeric cytokine composed of p28 and EBI3 subunits, has been reported to exert potent antitumor activity in several cancer models. However, the precise role of IL-27 in the pathogenesis of CRC remains unclear. Here, we show that during the azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced CRC development, IL-27p28 levels are dramatically increased in peripheral blood and tumor tissues, and the cytokine is mainly produced by tumor-infiltrating myeloid cells. IL-27p28 deficient mice display tumor resistances in both inflammation-associated CRC model and syngeneic MC38 colon cancer model. Administration with IL-27p28 neutralizing antibody also reduces the tumor formation in AOM/DSS-treated mice. Mechanically, CD8+ T cells in IL-27p28-/- mice exhibit enhanced tumor infiltration and cytotoxicity, which can be largely attributed to activation of the Akt/mTOR signaling pathway. Furthermore, selective depletion of CD8+ T cells in IL-27p28-/- mice markedly accelerate tumor growth and almost abrogate the protective effects of IL-27p28 deficiency. Most interestingly, the expression of IL-27p28 is also upregulated in tumor tissues of CRC patients and those with high expression of IL-27p28 tend to have a poorer overall survival. Our results suggest that loss of IL-27p28 suppresses colorectal tumorigenesis by augmenting CD8+ T cell-mediated anti-tumor immunity. Targeting IL-27p28 could be developed as a novel strategy for the treatment of colorectal cancers.

Research Progress of Interleukin-27 in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) can be identified as an inflammatory disorder in the intestine, being characterized by maladjusted immune responses and chronic inflammation of the intestinal tract. However, as the etiology and pathogenesis are still unclear, more effective therapeutic approaches are needed. Recent studies have discovered a new cytokine, interleukin-27 (IL-27), which belongs to the superfamily of IL-6 and IL-12, demonstrating multiple functions in many infectious diseases, autoimmune diseases, and cancers. Interleukin-27 is mainly produced by antigen presentation cells (APCs) such as dendritic cells and mononuclear macrophages, playing a dual regulatory role in immunological response. Therefore, this updated review aims to summarize the new progress of the regulatory role of IL-27 in IBD and focus more on the interaction between IL-27 and immune cells, hoping to provide more evidence for the potential IBD treatment mediated by IL-27.

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.

From bench to bedside: targeting lymphocyte activation gene 3 as a therapeutic strategy for autoimmune diseases

BACKGROUND

Immune checkpoints negatively regulate immune response, thereby playing an important role in maintaining immune homeostasis. Substantial studies have confirmed that blockade or deficiency of immune checkpoint pathways contributes to the deterioration of autoimmune diseases. In this context, focusing on immune checkpoints might provide alternative strategies for the treatment of autoimmunity. Lymphocyte activation gene 3 (LAG3), as a member of immune checkpoint, is critical in regulating immune responses as manifested in multiple preclinical studies and clinical trials. Recent success of dual-blockade of LAG3 and programmed death-1 in melanoma also supports the notion that LAG3 is a crucial regulator in immune tolerance.

METHODS

We wrote this review article by searching the PubMed, Web of Science and Google Scholar databases.

CONCLUSION

In this review, we summarize the molecular structure and the action mechanisms of LAG3. Additionally, we highlight its roles in diverse autoimmune diseases and discuss how the manipulation of the LAG3 pathway can serve as a promising therapeutic strategy as well as its specific mechanism with the aim of filling the gaps from bench to bedside.

The Role of Genetically Engineered Probiotics for Treatment of Inflammatory Bowel Disease: A Systematic Review

BACKGROUND

Many preclinical studies have demonstrated the effectiveness of genetically modified probiotics (gm probiotics) in animal models of inflammatory bowel disease (IBD).

OBJECTIVE

This systematic review was performed to investigate the role of gm probiotics in treating IBD and to clarify the involved mechanisms.

METHODS

PubMed, Web of Science, Cochrane Library, and Medline were searched from their inception to 18 September 2022 to identify preclinical and clinical studies exploring the efficacy of gm probiotics in IBD animal models or IBD patients. Two independent researchers extracted data from the included studies, and the data were pooled by the type of study; that is, preclinical or clinical.

RESULTS

Forty-five preclinical studies were included. In these studies, sodium dextran sulfate and trinitrobenzene sulfonic acid were used to induce colitis. Eleven probiotic species have been genetically modified to produce therapeutic substances, including IL-10, antimicrobial peptides, antioxidant enzymes, and short-chain fatty acids, with potential therapeutic properties against colitis. The results showed generally positive effects of gm probiotics in reducing disease activity and ameliorating intestinal damage in IBD models; however, the efficacy of gm probiotics compared to that of wild-type probiotics in many studies was unclear. The main mechanisms identified include modulation of the diversity and composition of the gut microbiota, production of regulatory metabolites by beneficial bacteria, reduction of the pro- to anti-inflammatory cytokine ratio in colonic tissue and plasma, modulation of oxidative stress activity in the colon, and improvement of intestinal barrier integrity. Moreover, only one clinical trial with 10 patients with Crohn's disease was included, which showed that L. lactis producing IL-10 was safe, and a decrease in disease activity was observed in these patients.

CONCLUSIONS

Gm probiotics have a certain efficacy in colitis models through several mechanisms. However, given the scarcity of clinical trials, it is important for researchers to pay more attention to gm probiotics that are more effective and safer than wild-type probiotics to facilitate further clinical translation.

IL27 Signaling Serves as an Immunologic Checkpoint for Innate Cytotoxic Cells to Promote Hepatocellular Carcinoma

Although inflammatory mechanisms driving hepatocellular carcinoma (HCC) have been proposed, the regulators of anticancer immunity in HCC remain poorly understood. We found that IL27 receptor (IL27R) signaling promotes HCC development in vivo. High IL27EBI3 cytokine or IL27RA expression correlated with poor prognosis for patients with HCC. Loss of IL27R suppressed HCC in vivo in two different models of hepatocarcinogenesis. Mechanistically, IL27R sig-naling within the tumor microenvironment restrains the cytotoxicity of innate cytotoxic lymphocytes. IL27R ablation enhanced their accumulation and activation, whereas depletion or functional impairment of innate cytotoxic cells abrogated the effect of IL27R disruption. Pharmacologic neutralization of IL27 signaling increased infiltration of innate cytotoxic lymphocytes with upregulated cytotoxic molecules and reduced HCC development. Our data reveal an unexpected role of IL27R signaling as an immunologic checkpoint regulating innate cytotoxic lymphocytes and promoting HCC of different etiologies, thus indicating a therapeutic potential for IL27 pathway blockade in HCC.

SIGNIFICANCE

HCC, the most common form of liver cancer, is characterized by a poor survival rate and limited treatment options. The discovery of a novel IL27-dependent mechanism controlling anticancer cytotoxic immune response will pave the road for new treatment options for this devastating disease. This article is highlighted in the In This Issue feature, p. 1825.

The Role of the Lymphatic System in the Pathogenesis and Treatment of Inflammatory Bowel Disease

Although the number of therapeutic options for the treatment of inflammatory bowel disease (IBD) has increased in recent years, patients suffer from decreased quality of life due to non-response or loss of response to the currently available treatments. An increased understanding of the disease’s etiology could provide novel insights for treatment strategies in IBD. Lymphatic system components are generally linked to immune responses and presumably related to inflammatory diseases pathophysiology. This review aims to summarize findings on immune-mediated mechanisms in lymphoid tissues linked with IBD pathogenesis and (potential) novel treatments. Enhanced innate and adaptive immune responses were observed in mesenteric lymph nodes (MLNs) and other lymphoid structures, such as Peyer’s patches, in patients with IBD and in animal models. Furthermore, the phenomenon of lymphatic obstruction in the form of granulomas in MLNs and lymphatic vessels correlates with disease activity. There is also evidence that abnormalities in the lymphatic stromal components and lymph node microbiome are common in IBD and could be exploited therapeutically. Finally, novel agents targeting lymphocyte trafficking have been added to the treatment armamentarium in the field of IBD. Overall, gut-associated lymphoid tissue plays a key role in IBD immunopathogenesis, which could offer novel therapeutic targets.

The effect of BKV reactivation on cytokines behavior in kidney transplanted patients

BACKGROUND

BK virus associated nephropathy (BKVAN) is one of the common causes of graft loss among kidney transplanted recipients (KTRs). The current treatment for BKV nephropathy is decreasing the immunosuppressive regimen in KTRs. Interleukin-27 (IL-27) is a multifunctional cytokine that might be the front-runner of an important pathway in this regard. Therefore, in current study it is tried to evaluate the changes in the expression level of IL-27 and some related molecules, resulting from BKV reactivation in KTR patients.

METHODS

EDTA-treated blood samples were collected from all participants. Patients were divided into two groups, 31 kidney transplant recipients with active and 32 inactive BKV infection, after being monitored by Real time PCR (Taq-Man) in plasma. Total of 30 normal individuals were considered as healthy control group. Real time PCR (SYBR Green) technique is used to determine the expression level of studied genes.

RESULTS

The results of gene expression comparisons showed that the expression level of IL-27, IFN-γ, TNF-α, TNFR2 and IRF7 genes was significantly higher in inactive group in comparison to active group. The expression level of TLR4 was lower in both active and inactive groups in comparison to control group. ROC curve analysis showed that IL-27 and IRF7 are significantly different amongst other studied genes. Finally, the analyses revealed that the expression level of most of the studied genes (except for TNF-α and TLR4) have significant correlation with viral load.

CONCLUSIONS

Our findings revealed that IL-27, IFN-γ, TNF-α, TNFR2 and IRF7 expression level is higher in inactive group and TLR4 expression level is lower in patients' groups in comparison to control group. Also, ROC curve analysis showed IL-27 and IRF7 can significantly differentiate studied groups (BKV active vs. inactive). Therefore, these results might help elucidating the pattern in charge of BKV reactivation in kidney transplanted patients.

Elevated Levels of IL-27 Are Associated with Disease Activity in Patients with Crohn's Disease

Immune disorders play an important role in the pathogenesis of Crohn's disease (CD). Notably, the increased immune response of Th1 cells and related cytokines is associated with the onset of CD. IL-27 is a newly discovered IL-12-related cytokine, but its expression and clinical significance in CD patients are still controversial. This study is aimed at evaluating the serum levels of IL-27 in CD patients and analyzing their clinical significance. The results indicated that serum levels of IL-27 in CD patients were significantly higher than those in control subjects (median (interquartile range (IQR)): 110.0 (95.0, 145.0) vs. 85.0 (80.0, 95.0) pg/ml, P < 0.001). Furthermore, the IL-27 levels significantly increased in CD patients at the active stage compared with CD patients in remission (CDR) (127.5 (100.0, 150.0) vs. 90 (80.0, 110.0) pg/ml, P < 0.001). However, there was no difference in IL-27 levels between CDR and control subjects. The levels of IL-27 were positively correlated with Crohn's disease activity index (CDAI), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), fecal calprotectin (FC), and Simple Endoscopic Score for Crohn's Disease (SES-CD) and negatively correlated with hemoglobin (Hb) and serum albumin (ALB). IL-27 combined with CRP favored the prediction of CD activity (area under the curve (AUC): 0.88). Additionally, the proportions of Th17 and Th1 cells in peripheral blood were higher in CD patients than in control subjects. Active CD patients exhibited significantly higher proportions of Th17 and Th1 cells than those in remission. Moreover, correlation analysis indicated that the serum levels of IL-27 were positively associated with the frequency of Th17 cells in CD patients (r = 0.519, P = 0.013) but not associated with the frequency of Th1 cells in CD patients. IL-27 is positively associated with multiple inflammation indicators and may exert a proinflammatory profile by regulating Th17 cell differentiation in the development of Crohn's disease. In the future, IL-27 combined with CRP is expected to become an important biological marker of CD activity.

New insights into IL-6 family cytokines in metabolism, hepatology and gastroenterology

IL-6 family cytokines are defined by the common use of the signal-transducing receptor chain glycoprotein 130 (gp130). Increasing evidence indicates that these cytokines are essential in the regulation of metabolic homeostasis as well as in the pathophysiology of multiple gastrointestinal and liver disorders, thus making them attractive therapeutic targets. Over the past few years, therapies modulating gp130 signalling have grown exponentially in several clinical settings including obesity, cancer and inflammatory bowel disease. A newly engineered gp130 cytokine, IC7Fc, has shown promising preclinical results for the treatment of type 2 diabetes, obesity and liver steatosis. Moreover, drugs that modulate gp130 signalling have shown promise in refractory inflammatory bowel disease in clinical trials. A deeper understanding of the main roles of the IL-6 family of cytokines during homeostatic and pathological conditions, their signalling pathways, sources of production and target cells will be crucial to the development of improved treatments. Here, we review the current state of the role of these cytokines in hepatology and gastroenterology and discuss the progress achieved in translating therapeutics targeting gp130 signalling into clinical practice.

Axial spondyloarthritis: emerging drug targets

INTRODUCTION

Axial spondyloarthritis (AxSpA) is an inflammatory disorder that affects the joints, entheses, and bone tissues and is sometimes associated with psoriasis, anterior uveitis, and gut inflammation. Its pathogenesis is not wholly understood and treatment strategies require optimization. Data concerning AxSpA pathogenesis support a critical role of abnormal CD4⁺ T cell differentiation and exacerbated type 3 immune response. This knowledge boosted the development of interleukin (IL)-17 and Janus kinase inhibitors for AxSpA treatment beyond tumor necrosis factor-α inhibition.

AREAS COVERED

Emerging drug targets in animal and cellular models and with phase-II clinical trials have been evaluated. We also reflect on key issues for preclinical and clinical research going forward.

EXPERT OPINION

Some of the most promising approaches include: (i) modulation of transforming growth factor-β family that could exert a specific role on bone formation; (ii) blockade of granulocyte-macrophage colony-stimulating factor that could reduce type 3 immune responses, and (iii) rebalancing of biased immune response by cytokines such as IL-2 or IL-27 that could favor anti-inflammatory response and sustained drug-free remission. Multiomics tools and artificial intelligence could contribute to identification of optimal targets and help stratify patients for the most appropriate treatment options.

Fermented Rice Bran Supplementation Prevents the Development of Intestinal Fibrosis Due to DSS-Induced Inflammation in Mice

Fermented rice bran (FRB) is known to protect mice intestines against dextran sodium sulfate (DSS)-induced inflammation; however, the restoration of post-colitis intestinal homeostasis using FRB supplementation is currently undocumented. In this study, we observed the effects of dietary FRB supplementation on intestinal restoration and the development of fibrosis after DSS-induced colitis. DSS (1.5%) was introduced in the drinking water of mice for 5 days. Eight mice were sacrificed immediately after the DSS treatment ended. The remaining mice were divided into three groups, comprising the following diets: control, 10% rice bran (RB), and 10% FRB-supplemented. Diet treatment was continued for 2 weeks, after which half the population of mice from each group was sacrificed. The experiment was continued for another 3 weeks before the remaining mice were sacrificed. FRB supplementation could reduce the general observation of colitis and production of intestinal pro-inflammatory cytokines. FRB also increased intestinal mRNA levels of anti-inflammatory cytokine, tight junction, and anti-microbial proteins. Furthermore, FRB supplementation suppressed markers of intestinal fibrosis. This effect might have been achieved via the canonical Smad2/3 activation and the non-canonical pathway of Tgf-β activity. These results suggest that FRB may be an alternative therapeutic agent against inflammation-induced intestinal fibrosis.

Cytokine-Mediated Crosstalk between Immune Cells and Epithelial Cells in the Gut

Cytokines are small proteins that are secreted by a vast majority of cell types in the gut. They not only establish cell-to-cell interactions and facilitate cellular signaling, but also regulate both innate and adaptive immune responses, thereby playing a central role in genetic, inflammatory, and infectious diseases of the gut. Both, immune cells and gut epithelial cells, play important roles in intestinal disease development. The epithelium is located in between the mucosal immune system and the gut microbiome. It not only establishes an efficient barrier against gut microbes, but it also signals information from the gut lumen and its composition to the immune cell compartment. Communication across the epithelial cell layer also occurs in the other direction. Intestinal epithelial cells respond to immune cell cytokines and their response influences and shapes the microbial community within the gut lumen. Thus, the epithelium should be seen as a translator or a moderator between the microbiota and the mucosal immune system. Proper communication across the epithelium seems to be a key to gut homeostasis. Indeed, current genome-wide association studies for intestinal disorders have identified several disease susceptibility loci, which map cytokine signatures and their related signaling genes. A thorough understanding of this tightly regulated cytokine signaling network is crucial. The main objective of this review was to shed light on how cytokines can orchestrate epithelial functions such as proliferation, cell death, permeability, microbe interaction, and barrier maintenance, thereby safeguarding host health. In addition, cytokine-mediated therapy for inflammation and cancer are discussed.

Interplay between Cytokine Circuitry and Transcriptional Regulation Shaping Helper T Cell Pathogenicity and Plasticity in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic disorder manifested as Crohn’s disease (CD) and ulcerative colitis (UC) characterized by intestinal inflammation and involves a dysregulated immune response against commensal microbiota through the activation of CD4 T helper cells. T helper cell differentiation to effector or regulatory phenotypes is controlled by cytokine networks and transcriptional regulators. Distinct polarized T helper cells are able to alter their phenotypes to adapt to diverse and fluctuating physiological environments. T helper cells exhibit intrinsic instability and flexibility to express cytokines of other lineages or transdifferentiate from one T helper cell type to another in response to various perturbations from physiological cytokine milieu as a means of promoting local immunity in response to injury or ensure tissue homeostasis. Furthermore, functional plasticity and diversity of T helper cells are associated with pathogenicity and are critical for immune homeostasis and prevention of autoimmunity. In this review, we provide deeper insights into the combinatorial extrinsic and intrinsic signals that control plasticity and transdifferentiation of T helper cells and also highlight the potential of exploiting the genetic reprogramming plasticity of T helper cells in the treatment of IBD.

IL-27 Counteracts Neuropathic Pain Development Through Induction of IL-10

Neuroimmune–glia interactions have been implicated in the development of neuropathic pain. Interleukin-27 (IL-27) is a cytokine that presents regulatory activity in inflammatory conditions of the central nervous system. Thus, we hypothesized that IL-27 would participate in the neuropathic pain process. Here, we found that neuropathic pain caused by peripheral nerve injury (spared nerve injury model; SNI), was enhanced in IL-27-deficient^(−/−) mice, whereas nociceptive pain is similar to that of wild-type mice. SNI induced an increase in the expression of IL-27 and its receptor subunit (Wsx1) in the sensory ganglia and spinal cord. IL-27 receptor was expressed mainly in resident macrophage, microglia, and astrocytes of the sensory ganglia and spinal cord, respectively. Finally, we identify that the antinociceptive effect of IL-27 was not observed in IL-10^−/− mice. These results provided evidence that IL-27 is a cytokine produced after peripheral nerve injury that counteracts neuropathic pain development through induction of the antinociceptive cytokine IL-10. In summary, our study unraveled the role of IL-27 as a regulatory cytokine that counteracts the development of neuropathic pain after peripheral nerve damage. In conclusion, they indicate that immunotherapies based on IL-27 could emerge as possible therapeutic approaches for the prevention of neuropathic pain development after peripheral nerve injury.

The cytokine network involved in the host immune response to periodontitis

Periodontitis is an inflammatory disease involving the destruction of both soft and hard tissue in the periodontal region. Although dysbiosis of the local microbial community initiates local inflammation, over-activation of the host immune response directly activates osteoclastic activity and alveolar bone loss. Many studies have reported on the cytokine network involved in periodontitis and its crucial and pleiotropic effect on the recruitment of specific immunocytes, control of pathobionts and induction or suppression of osteoclastic activity. Nonetheless, particularities in the stimulation of pathogens in the oral cavity that lead to the specific and complex periodontal cytokine network are far from clarified. Thus, in this review, we begin with an up-to-date aetiological hypothesis of periodontal disease and summarize the roles of cytokines in the host immune response. In addition, we also summarize the latest cytokine-related therapeutic measures for periodontal disease.

IL27Rα Deficiency Alters Endothelial Cell Function and Subverts Tumor Angiogenesis in Mammary Carcinoma

IL-27 regulates inflammatory diseases by exerting a pleiotropic impact on immune cells. In cancer, IL-27 restricts tumor growth by acting on tumor cells directly, while its role in the tumor microenvironment is still controversially discussed. To explore IL-27 signaling in the tumor stroma, we used a mammary carcinoma syngraft approach in IL27Rα-deficient mice. Tumor growth in animals lacking IL27Rα was markedly reduced. We noticed a decrease in immune cell infiltrates, enhanced tumor cell death, and fibroblast accumulation. However, most striking changes pertain the tumor vasculature. Tumors in IL27Rα-deficient mice were unable to form functional vessels. Blocking IL-27-STAT1 signaling in endothelial cells in vitro provoked an overshooting migration/sprouting of endothelial cells. Apparently, the lack of the IL-27 receptor caused endothelial cell hyper-activation via STAT1 that limited vessel maturation. Our data reveal a so far unappreciated role of IL-27 in endothelial cells with importance in pathological vessel formation.

The Immunobiology of the Interleukin-12 Family: Room for Discovery

The discovery of interleukin (IL)-6 and its receptor subunits provided a foundation to understand the biology of a group of related cytokines: IL-12, IL-23, and IL-27. These family members utilize shared receptors and cytokine subunits and influence the outcome of cancer, infection, and inflammatory diseases. Consequently, many facets of their biology are being therapeutically targeted. Here, we review the landmark discoveries in this field, the combinatorial biology inherent to this family, and how patient datasets have underscored the critical role of these pathways in human disease. We present significant knowledge gaps, including how similar signals from these cytokines can mediate distinct outcomes, and discuss how a better understanding of the biology of the IL-12 family provides new therapeutic opportunities.

Tipping the balance: inhibitory checkpoints in intestinal homeostasis

The small intestinal and colonic lamina propria are populated with forkhead box P3 (FOXP3)⁺CD4⁺ regulatory T cells (Tregs) and interleukin-10-producing T cells that orchestrate intestinal tolerance to harmless microbial and food antigens. Expression of co-inhibitory receptors such as CTLA-4 and PD-1 serve as checkpoints to these cells controlling their T-cell receptor (TCR)-mediated and CD28-mediated activation and modulating the phenotype of neighboring antigen presenting cells. Recent discoveries on the diversity of co-inhibitory receptors and their selective cellular expression has shed new light on their tissue-dependent function. In this review, we provide an overview of the co-inhibitory pathways and checkpoints of Treg and effector T cells and their mechanisms of action in intestinal homeostasis. Better understanding of these inhibitory checkpoints is desired as their blockade harbors clinical potential for the treatment of cancer and their stimulation may offer new opportunities to treat chronic intestinal inflammation such as inflammatory bowel disease.

SUMOylation of ROR-γt inhibits IL-17 expression and inflammation via HDAC2

Dysregulated ROR-γt-mediated IL-17 transcription is central to the pathogenesis of several inflammatory disorders, yet the molecular mechanisms that govern the transcription factor activity of ROR-γt in the regulation of IL-17 are not fully defined. Here we show that SUMO-conjugating enzyme Ubc9 interacts with a conserved GKAE motif in ROR-γt to induce SUMOylation of ROR-γt and suppress IL-17 expression. Th17 cells expressing SUMOylation-defective ROR-γt are highly colitogenic upon transfer to Rag1^–/– mice. Mechanistically, SUMOylation of ROR-γt facilitates the binding of HDAC2 to the IL-17 promoter and represses IL-17 transcription. Mice with conditional deletion of HDAC2 in CD4⁺ T cells have elevated IL-17 expression and severe colitis. The identification of the Ubc9/ROR-γt/HDAC2 axis that governs IL-17 expression may open new venues for the development of therapeutic measures for inflammatory disorders.

Interleukin-17 (IL-17)-secreting CD4 T cells (Th17) are induced by the master transcription factor RORγt, and are important for anti-fungal immunity and inflammatory responses. Here the authors show that Ubc9-mediated SUMOylation of RORγt induces HDAC2 binding to IL-17 promoter for suppressing IL-17 production in Th17 cells.

Can We Target Endogenous Anti-inflammatory Responses as a Therapeutic Strategy for Inflammatory Bowel Disease?

Inflammatory bowel disease (IBD) describes chronic relapsing remitting inflammation of the gastrointestinal tract including ulcerative colitis and Crohn's disease. The prevalence of IBD is rising across the globe. Despite a growing therapeutic arsenal, current medical treatments are not universally effective, do not induce lasting remission in all, or are accompanied by short- and long-term adverse effects. Therefore, there is a clinical need for novel therapeutic strategies for IBD. Current treatments for IBD mainly manipulate the immune system for therapeutic gain by inhibiting pro-inflammatory activity. There is a robust endogenous immunoregulatory capacity within the repertoire of both innate and adaptive immune responses. An alternative treatment strategy for IBD is to hijack and bolster this endogenous capability for therapeutic gain. This review explores this hypothesis and presents current evidence for this therapeutic direction in immune cell function, cytokine biology, and alternative mechanisms of immunoregulation such as microRNA, oligonucleotides, and the endocannabinoid system.

Interleukin-27 Gene Therapy Prevents the Development of Autoimmune Encephalomyelitis but Fails to Attenuate Established Inflammation due to the Expansion of CD11b+Gr-1+ Myeloid Cells

Interleukin-27 (IL-27) and its subunit P28 (also known as IL-30) have been shown to inhibit autoimmunity and have been suggested as potential immunotherapeutic for autoimmune diseases such as multiple sclerosis (MS). However, the potential of IL-27 and IL-30 as immunotherapeutic, and their mechanisms of action have not been fully understood. In this study, we evaluated the efficacy of adeno-associated viral vector (AAV)-delivered IL-27 (AAV-IL-27) and IL-30 (AAV-IL-30) in a murine model of MS. We found that one single administration of AAV-IL-27, but not AAV-IL-30 completely blocked the development of experimental autoimmune encephalomyelitis (EAE). AAV-IL-27 administration reduced the frequencies of Th17, Treg, and GM-CSF-producing CD4+ T cells and induced T cell expression of IFN-γ, IL-10, and PD-L1. However, experiments involving IL-10-deficient mice and PD-1 blockade revealed that AAV-IL-27-induced IL-10 and PD-L1 expression were not required for the prevention of EAE development. Surprisingly, neither AAV-IL-27 nor AAV-IL-30 treatment inhibited EAE development and Th17 responses when given at disease onset. We found that mice with established EAE had significant expansion of CD11b+Gr-1+ cells, and AAV-IL-27 treatment further expanded these cells and induced their expression of Th17-promoting cytokines such as IL-6. Adoptive transfer of AAV-IL-27-expanded CD11b+Gr-1+ cells enhanced EAE development. Thus, expansion of CD11b+Gr-1+ cells provides an explanation for the resistance to IL-27 therapy in mice with established disease.

Interleukin 27 is up-regulated in patients with active inflammatory bowel disease

The aim of the study was to characterize and quantify tissue gene and protein expression of IL-27 in ulcerative colitis (UC) and Crohn's disease (CD) patients. This is an observational and cross-sectional study. Fifty-four patients with IBD were studied: 27 active UC, 12 inactive UC, 10 active CD, and 5 inactive CD. All patients belonged to the Inflammatory Bowel Disease Clinic at the Instituto Nacional de Ciencias Médicas y Nutrición. We found that IL-27 gene expression was significantly higher in active UC versus inactive UC group (P = 0.015). The IL-27 mRNA expression was increased in patients with active CD compared with inactive CD disease (P = 0.035). The percentage of IL-27 immunoreactive cells was higher in active UC versus active CD patients and non-inflamed tissue controls. The IL-27 was significantly elevated in active UC and CD patients, and it was associated with disease severity.

Recent Advances: The Imbalance of Cytokines in the Pathogenesis of Inflammatory Bowel Disease

Cytokines play an important role in the immunopathogenesis of inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, where they drive and regulate multiple aspects of intestinal inflammation. The imbalance between proinflammatory and anti-inflammatory cytokines that occurs in IBD results in disease progression and tissue damage and limits the resolution of inflammation. Targeting cytokines have been novel strategies in the treatment of IBD. Recent studies show the beneficial effects of anticytokine treatments to IBD patients, and multiple novel cytokines are found to be involved in the pathogenesis of IBD. In this review, we will discuss the recent advances of novel biologics in clinics and clinical trials, and novel proinflammatory and anti-inflammatory cytokines found in IBD with focusing on IL-12 family and IL-1 family members as well as their relevance to the potential therapy of IBD.

Applications of Genetically Modified Immunobiotics with High Immunoregulatory Capacity for Treatment of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs), including ulcerative colitis and Crohn’s disease, are chronic inflammatory diseases characterized by dysregulated immune responses of the gastrointestinal tract. In recent years, the incidence of IBDs has increased in developed nations, but their prophylaxis/treatment is not yet established. Site-directed delivery of molecules showing anti-inflammatory properties using genetically modified (gm)-probiotics shows promise as a new strategy for the prevention and treatment of IBD. Advantages of gm-probiotics include (1) the ability to use bacteria as a delivery vehicle, enabling safe and long-term use by humans, (2) decreased risks of side effects, and (3) reduced costs. The intestinal delivery of anti-inflammatory proteins such as cytokines and enzymes using Lactococcus lactis has been shown to regulate host intestinal homeostasis depending on the delivered protein-specific machinery. Additionally, clinical experience using interleukin 10-secreting Lc. lactis has been shown to be safe and to facilitate biological containment in IBD therapy. On the other hand, some preclinical studies have demonstrated that gm-strains of immunobiotics (probiotic strains able to beneficially regulate the mucosal immunity) provide beneficial effects on intestinal inflammation as a result of the synergy between the immunoregulatory effects of the bacterium itself and the anti-inflammatory effects of the delivered recombinant proteins. In this review, we discuss the rapid progression in the development of strategies for the prophylaxis and treatment of IBD using gm-probiotics that exhibit immune regulation effects (gm-immunobiotics). In particular, we discuss the type of strains used as delivery agents.

Interleukin-27 as a Novel Therapy for Inflammatory Bowel Disease: A Critical Review of the Literature

Inflammatory bowel disease (IBD) is an inflammatory disorder of the intestine that affects an estimated 329 per 100,000 people in the United States and is increasing in incidence within a number of cultures worldwide. Likely due to its incompletely understood pathophysiology and etiology, the standard treatments for IBD are only efficacious in subsets of patients and often do not induce lasting remission. As a result, novel therapies are needed. The success of anti-tumor necrosis factor-α treatment in a subset of patients with IBD demonstrated that therapy targeting a single cytokine could be efficacious in IBD, and clinical trials investigating the blockade of a variety of cytokines have commenced. Interleukin (IL) 27 is a relatively recently discovered type I cytokine with established roles in infectious disease, autoimmunity, and cancer in a variety of organs. IL-27 was identified as a candidate gene for IBD, and a number of studies in mouse models of IBD have demonstrated that IL-27 therapy is protective. However, in contrast to these investigations, genetic deletion of the IL-27 receptor has been shown to be protective in some mouse models of IBD. The purpose of this review is to highlight the recent literature investigating the role of IL-27 in IBD and to discuss the possible explanations for the sometimes conflicting results of these studies. Evidence supporting IL-27 therapy as a treatment for IBD will also be discussed.

Systemic delivery of IL-27 by an adeno-associated viral vector inhibits T cell-mediated colitis and induces multiple inhibitory pathways in T cells

IL-27 is a heterodimeric cytokine that is composed of two subunits, i.e., EBV-induced gene 3 and IL-27p28 (also known as IL-30). Although the role of endogenous IL-27 in the pathogenesis of autoimmune colitis, an experimental model of human inflammatory bowel disease, remains controversial, IL-27 local delivery has been shown to inhibit autoimmune colitis. IL-30 has been shown to inhibit Th1 and Th17 responses and is considered a potential therapeutic for certain autoimmune diseases. In this study, we have compared the therapeutic efficacy of adeno-associated viral vector-delivered IL-27 and IL-30 in a murine model of autoimmune colitis. We found that 1 single administration of adeno-associated viral vector-delivered IL-27, but not adeno-associated viral vector-delivered IL-30, nearly completely inhibited autoimmune colitis. Adeno-associated viral vector-delivered IL-27 administration inhibited Th17 responses and induced T cell expression of IL-10, programmed death ligand 1, and stem cell antigen 1. Intriguingly, adeno-associated viral vector-delivered IL-27 treatment enhanced Th1 responses and inhibited regulatory T cell responses. Experiments involving the adoptive transfer of IL-10-deficient T cells revealed that adeno-associated viral vector-delivered IL-27-induced IL-10 production was insufficient to mediate inhibition of autoimmune colitis, whereas anti-programmed death 1 antibody treatment resulted in the breaking of adeno-associated viral vector-delivered IL-27-induced T cell tolerance. Thus, systemic delivery of IL-27 inhibits Th17 responses and induces multiple inhibitory pathways, including programmed death ligand 1 in T cells, and adeno-associated viral vector-delivered IL-27, but not IL-30, may have a therapeutic potential for the treatment of human inflammatory bowel disease.

Protective role of Interleukin 27 (IL-27) gene polymorphisms in patients with ulcerative colitis

Ulcerative colitis (UC) is a chronic condition of unknown etiology and a polygenic disease. The interleukin 27 (IL-27) have been implicated in the pathogenesis of several autoimmune diseases including inflammatory bowel disease. Several polymorphisms of IL-27 have been associated with several types of cancer and immune disorders. The aim of the present study was to evaluate the association between IL-27 gene polymorphisms and the development of UC. Four polymorphisms of IL-27p28 gene (rs181206, rs26528, rs17855750, and rs40837) and three of the Epstein-Barr virus-induced gene 3 (EBI3) (rs428253, rs4740, and rs4905) were genotyped by 5' exonuclease TaqMan genotyping assays on an ABI Prism 7900HT Fast Real-Time PCR System in 375 Mexican patients with UC and 1599 Mexican Mestizo healthy unrelated individuals. IL-27 levels were determined in 458 healthy controls. Under recessive model adjusted by age and gender, the IL-27p28 rs17855750 polymorphism was associated with decreased risk of developing UC (OR=0.27, 95% CI: 0.06-1.13, P=0.031). On the other hand, under recessive models adjusted by age and gender, the EBI3 rs428253 (OR=0.54, 95% CI: 0.29-0.99, P=0.035), rs4740 (OR=0.60, 95% CI: 0.36-1.01, P=0.046) and rs4905 (OR=0.59, 95% CI: 0.35-1.01, P=0.043) were associated with decreased risk of developing UC. Similar levels of IL-27 were observed among the genotypes of the studied polymorphisms. IL-27 polymorphisms might play a protective role for the development of UC in the Mexican population.

Role of interleukin-27 in inflammatory bowel disease

Inflammatory bowel disease (IBD), which is characterized by chronic or recurrent relapsing gastrointestinal inflammation, includes ulcerative colitis (UC) and Crohn's disease (CD). The pathogenesis of IBD remains obscure, however, abnormal immune responses are regarded as the major component of IBD pathogenesis. Interleukin-27 (IL-27) is a new member of the IL-12 family, and it is produced by activated antigen-presenting cells and plays an important role in the differentiation and function of different T cell subsets. IL-27 has various immunoregulatory functions and is implicated in the pathogenesis of many infectious and autoimmune diseases. Recent studies have showed that IL-27 is strongly associated with the genesis and development of IBD. Here we provide an overview of the role of IL-27 in the pathogenesis of IBD.

Histamine H2 Receptor-Mediated Suppression of Intestinal Inflammation by Probiotic Lactobacillus reuteri

Probiotics and commensal intestinal microbes suppress mammalian cytokine production and intestinal inflammation in various experimental model systems. Limited information exists regarding potential mechanisms of probiotic-mediated immunomodulation in vivo. In this report, we demonstrate that specific probiotic strains of Lactobacillus reuteri suppress intestinal inflammation in a trinitrobenzene sulfonic acid (TNBS)-induced mouse colitis model. Only strains that possess the hdc gene cluster, including the histidine decarboxylase and histidine-histamine antiporter genes, can suppress colitis and mucosal cytokine (interleukin-6 [IL-6] and IL-1β in the colon) gene expression. Suppression of acute colitis in mice was documented by diminished weight loss, colonic injury, serum amyloid A (SAA) protein concentrations, and reduced uptake of [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) in the colon by positron emission tomography (PET). The ability of probiotic L. reuteri to suppress colitis depends on the presence of a bacterial histidine decarboxylase gene(s) in the intestinal microbiome, consumption of a histidine-containing diet, and signaling via the histamine H2 receptor (H2R). Collectively, luminal conversion of l-histidine to histamine by hdc⁺L. reuteri activates H2R, and H2R signaling results in suppression of acute inflammation within the mouse colon.

Probiotics are microorganisms that when administered in adequate amounts confer beneficial effects on the host. Supplementation with probiotic strains was shown to suppress intestinal inflammation in patients with inflammatory bowel disease and in rodent colitis models. However, the mechanisms of probiosis are not clear. Our current studies suggest that supplementation with hdc⁺L. reuteri, which can convert l-histidine to histamine in the gut, resulted in suppression of colonic inflammation. These findings link luminal conversion of dietary components (amino acid metabolism) by gut microbes and probiotic-mediated suppression of colonic inflammation. The effective combination of diet, gut bacteria, and host receptor-mediated signaling may result in opportunities for therapeutic microbiology and provide clues for discovery and development of next-generation probiotics.

IL-27-induced modulation of autoimmunity and its therapeutic potential

Interleukin-27 (IL-27) is a new member of the IL-12 family. It is produced by activated antigen-presenting cells and plays an important role in the regulation of CD4+ T cell differentiation and immune response. IL-27 activates multiple signaling cascades, including the JAK-STAT and p38 MAPK pathways. Several studies have revealed that IL-27 promotes the differentiation of Th1 and Tr1, but inhibits Th2, Th17, and Treg cells. However, a few studies have shown an opposite effect on certain T cell subsets, such as Treg. IL-27 displays both pro- and anti- inflammatory activities in different autoimmune diseases. Here, we have discussed the role of IL-27 in rheumatoid arthritis, multiple sclerosis, colitis, lupus, psoriasis, type 1 diabetes, and uveitis. Most of this information is derived from experimental models of these autoimmune diseases. The mechanistic basis of the dual role of IL-27 in inflammation and autoimmunity is still not fully defined. In general, the pro-/anti-inflammatory activity of IL-27 is influenced by the underlying immune effector pathways, the phase of the disease, the presence or absence of counter-regulatory cytokines/T cell subsets, and the tissue/cell type under study. Despite a spectrum of outcomes in various autoimmune diseases, mostly anti-inflammatory and immunomodulatory effects of IL-27 have been observed in this category of diseases. Accordingly, IL-27 represents a novel, promising target/agent for the treatment of autoimmune diseases.

Increased IL-21/IL-21R expression and its proinflammatory effects in autoimmune thyroid disease

To determine the potential role of interleukin-21 (IL-21) / IL-21 receptor (IL-21R) in the pathogenesis of autoimmune thyroid disease (AITD) mainly known as Graves' disease (GD) and Hashimoto's thyroiditis (HT). IL-21 and IL-21R of peripheral blood samples and/or thyroid tissues from AITD patients and healthy controls were analyzed by ELISA, quantitative real-time polymerase chain reaction (qRT-PCR), flow cytometry and immunohistochemistry. In vitro, the mRNA and protein of inflammatory cytokines of cultured peripheral blood mononuclear cells (PBMCs) upon recombinant human IL-21 (rhIL-21) stimulation were detected. There was an increased serum concentration of IL-21 in untreated GD and HT patients, and IL-21(+)CD3(+)CD8(-)T cells were significantly increased in PBMCs of HT patients compared with healthy volunteers. The IL-21 mRNA expression in PBMCs increased dramatically in GD and HT patients, and marked augmentations of IL-21 and IL-21R mRNA in thyroid tissues of HT patients were observed. Immunohistochemical staining confirmed the expression of IL-21R protein in HT thyroid cells and lymphocytes. In vitro, PBMCs from GD cultured with rhIL-21 induced increased IL-17A but decreased IL-4 production, while from HT stimulated by rhIL-21 induced augmented production of IFN-γ. In conclusion, the expression of IL-21 and IL-21R were up-regulated in AITD and may be involved in the pathogenesis of the disease through augmenting aberrant immune cascade.

Insulin-like growth factor-1 endues monocytes with immune suppressive ability to inhibit inflammation in the intestine

The pathogenesis of some chronic inflammation such as inflammatory bowel disease is unclear. Insulin-like growth factor-1 (IGF1) has active immune regulatory capability. This study aims to investigate into the mechanism by which IGF1 modulates the monocyte (Mo) properties to inhibit immune inflammation in the intestine. In this study, the production of IGF1 by intestinal epithelial cells was evaluated by real time RT-PCR and Western blotting. Mos were analyzed by flow cytometry. A mouse colitis model was created with trinitrobenzene sulfonic acid. The results showed that mouse IECs produced IGF1, which could be up regulated by exposure to CpG-ODN (CpG-oligodeoxynueleotides) in the culture. Culture the CpG-ODN-primed IEC cells and Mos or exposure of Mos to IGF1 in the culture induced the Mos to express IL-10. The IGF1-primed Mos showed the immune suppressive effect on inhibiting the immune inflammation in the mouse colon. In conclusion, the IGF1-primed Mos are capable of suppressing immune inflammation in the intestine.

Resident bacteria-stimulated IL-10-secreting B cells ameliorate T cell-mediated colitis by inducing Tr-1 cells that require IL-27-signaling

BACKGROUND & AIMS

Regulatory roles of IL-10-producing B cells in colitis are not fully understood. The aim of this study is to explore the molecular mechanisms by which these cells modulate mucosal homeostasis.

METHODS

CD4⁺ T cells from WT, Il10^-/- or Il27ra^-/- mice were co-transferred with B cells from specific pathogen-free (SPF) or germ-free (GF) WT or Il10^-/- mice into Rag2^-/-Il10^-/- (DKO) mice and the severity of colitis and intestinal regulatory T cell populations were characterized. In vitro, WT or Il10^-/- B cells were co-cultured with unfractionated, naïve or regulatory T cells plus Il10^-/- antigen-presenting cells and stimulated with cecal bacterial lysate (CBL) with or without IL-27 or anti-IL-10R blockade. Gene expressions, cytokines in the supernatant and cell populations were assessed.

RESULTS

WT but not Il10^-/- B cells attenuate Th1/Th17-mediated colitis in DKO mice that also received WT but not Il10^-/- T cells. In vitro, CBL-stimulated WT B cells secrete abundant IL-10 and suppress IFNγ and IL-17a-production by T cells without requiring cell contact. Although both WT and Il10^-/- B cells induce Foxp3⁺CD4⁺ Tregs, only WT B cells induce IL-10-producing (Foxp3-negative) T regulatory-1 (Tr-1) cells both in vivo and in vitro. However, IL-10-producing B cells did not attenuate colitis or induce Tr-1 cells in the absence of T cell IL-27-signaling in vivo. WT B cell-dependent Tr-1 induction and concomitant decreased IFNγ-secretion were also mediated by T-cell IL-27-signaling in vitro.

CONCLUSIONS

IL-10-secreting B cells activated by physiologically-relevant bacteria ameliorate T cell-mediated colitis and contribute to intestinal homeostasis by suppressing effector T cells and inducing Tr-1 cells via IL-27-signaling on T cells.

The Th17 pathway as a therapeutic target in rheumatoid arthritis and other autoimmune and inflammatory disorders

Production of the pro-inflammatory cytokine interleukin (IL)-17 by Th17 cells and other cells of the immune system protects the host against bacterial and fungal infections, but also promotes the development of rheumatoid arthritis (RA) and other autoimmune and inflammatory disorders. Several biologicals targeting IL-17, the IL-17 receptor, or IL-17-related pathways are being tested in clinical trials, and might ultimately lead to better treatment for patients suffering from various IL-17-mediated disorders. In this review, we provide a clear overview of current knowledge on Th17 cell regulation and the main Th17 effector cytokines in relation to IL-17-mediated conditions, as well as on recent IL-17-related drug developments. We demonstrate that targeting the Th17 pathway is a promising treatment for rheumatoid arthritis and various other autoimmune and inflammatory diseases. However, improvements in technical developments assisting in the identification of patients suffering from IL-17-driven disease are needed to enable the application of tailor-made, personalized medicine.

A soluble form of IL-27Rα is a natural IL-27 antagonist

IL-27 is a cytokine of the IL-12 family that plays a key role in the regulation of inflammatory and T cell responses. Its receptor is composed of IL-27Rα and gp130 and activates the STAT pathway. We show in this study, using an ELISA that we developed, that a naturally occurring soluble form of IL-27Rα (sIL-27Rα) is produced by human activated CD4(+) and CD8(+) T cells, B cells, myeloid cells, and various cell lines. sIL-27Rα is present at a mean concentration of 10,344 ± 1,274 pg/ml in the sera from healthy individuals. Biochemical studies showed that sIL-27Rα is released as two N-glycosylated variants of ∼ 90 and ∼ 70 kDa. In IL-27Rα-transfected COS7 cells, primary cells, and cell lines, production of sIL-27Rα is inhibited by the metalloprotease inhibitors GM6001 and TAPI-0. Importantly, natural sIL-27Rα binds rIL-27, inhibits IL-27 binding to its cell surface receptor, and is a potent inhibitor of IL-27 signaling, as shown by its ability to specifically block IL-27-mediated STAT activation, at low molar excess over IL-27. Also, we found that serum levels of sIL-27Rα were elevated in patients with Crohn's disease, a Th1-mediated disease. These findings suggest that sIL-27Rα may play important immunoregulatory functions under normal and pathological conditions.

Oral delivery of IL-27 recombinant bacteria attenuates immune colitis in mice

BACKGROUND & AIMS

Treatment of inflammatory bowel disease would benefit from specific targeting of therapeutics to the intestine. We developed a strategy for localized delivery of the immunosuppressive cytokine interleukin (IL)-27, which is synthesized actively in situ by the food-grade bacterium Lactococcus lactis (LL-IL-27), and tested its ability to reduce colitis in mice.

METHODS

The 2 genes encoding mouse IL-27 were synthesized with optimal codon use for L lactis and joined with a linker; a signal sequence was added to allow for product secretion. The construct was introduced into L lactis. Colitis was induced via transfer of CD4(+)CD45RB(hi) T cells into Rag(-/-) mice to induce colitis; 7.5 weeks later, LL-IL-27 was administered to mice via gavage. Intestinal tissues were collected and analyzed.

RESULTS

LL-IL-27 administration protected mice from T-cell transfer-induced enterocolitis and death. LL-IL-27 reduced disease activity scores, pathology features of large and small bowel, and levels of inflammatory cytokines in colonic tissue. LL-IL-27 also reduced the numbers of CD4(+) and IL-17(+) T cells in gut-associated lymphoid tissue. The effects of LL-IL-27 required production of IL-10 by the transferred T cells. LL-IL-27 was more effective than either LL-IL-10 or systemic administration of recombinant IL-27 in reducing colitis in mice. LL-IL-27 also reduced colitis in mice after administration of dextran sodium sulfate.

CONCLUSIONS

LL-IL-27 reduces colitis in mice by increasing the production of IL-10. Mucosal delivery of LL-IL-27 could be a more effective and safer therapy for inflammatory bowel disease.

Prebiotic consumption in pregnant and lactating women increases IL-27 expression in human milk

The consumption of probiotics by pregnant and lactating women may prevent the onset of allergic disorders in their children by increasing the concentrations of immunoactive agents such as cytokines in breast milk. Prebiotics such as fructo-oligosaccharides (FOS) increase the number of beneficial organisms such as bifidobacteria. Thus, prebiotics may have an effect similar to that of probiotics. The objective of the present study was to carry out a comprehensive analysis of mRNA expression in human milk cells to identify changes in the concentrations of cytokines in breast milk after the consumption of FOS (4 g × 2 times/d) by pregnant and lactating women. The microarray analysis of human milk cells demonstrated that the expression levels of five genes in colostrum samples and fourteen genes in 1-month breast milk samples differed more than 3-fold between the FOS and control groups (sucrose group). The mRNA expression level of IL-27, a cytokine associated with immunoregulatory function, was significantly higher in 1-month breast milk samples obtained from the FOS group than in those obtained from the control group. In addition, the protein concentrations of IL-27 in colostrum and 1-month breast milk samples were significantly higher in the FOS group than in the control group. In conclusion, the consumption of FOS by pregnant and lactating women increases the production of IL-27 in breast milk. Future studies will address the association of this phenomenon with the onset of allergic disorders in children.

Bioengineering heterodimeric cytokines: turning promiscuous proteins into therapeutic agents

The interleukin 12 (IL-12) family comprises a group of heterodimeric cytokines that can cope with a great variety of immune conditions as the microenvironment demands. By sharing cytokine and receptor subunits, IL-12 (comprised of p40/p35 subunits), IL-23 (p40/p19), IL-27 (p28/EBI3), and IL-35 (p35/EBI3) represent, as a whole, a highly versatile system participating in controlling the continuum from inflammation to tolerance. Promiscuity, a peculiar feature of those cytokines, is a powerful and economic means of producing individual factors with distinct activities via different combinations of a single set of subunits. Whereas IL-12 and IL-23 have a clearly dominant immunostimulatory functional profile and IL-35 is a potent immunosuppressive agent, IL-27 can exert both adjuvant and regulatory effects, depending on the cytokine milieu. Promiscuity itself, however, may significantly hamper the therapeutic use of heterodimeric cytokines. The subunits of a recombinant cytokine, when administered in its native form, will rapidly dissociate in vivo and reassociate with alternative partners, thus generating different heterodimeric or even homodimeric molecules (i.e., p40/p40) with unwanted effects. As in other areas, bioengineering has provided a formidable tool to overcome the constraints associated with the potential use of IL-12 family cytokines. The generation of several gene constructs expressing IL-12, IL-23, IL-27, IL-35, or even the homodimer p40/p40, in their monomerized, single-chain form has allowed us to unveil the efficacy of those molecules in several experimental settings, including neoplasia, viral infection, chronic inflammation, allergy and autoimmunity. Although work is still needed to obtain an overall picture of therapeutic vs. adverse effects of individual molecules before any use in humans, the new frontiers of bioengineering are now driving the production of completely new combinations of cytokine subunits that may further extend the potential clinical use of such eclectic proteins.

Modulation of inflammation by interleukin-27

A growing body of evidence suggests an essential role of the heterodimeric cytokine, IL-27, for regulating immunity. IL-27 is composed of two subunits (p28 and EBI3) and is classified as a member of the IL-12 family of cytokines. APCs have been recognized as a major cellular source of IL-27 following activation with microbial products or IFNs (types I and II). In this review, we describe the current knowledge of the implications of IL-27 during the pathogenesis of infectious and autoimmune diseases. Experimental studies have used genetically targeted IL-27RA-/- mice, EBI3-/- mice, and p28-/- mice or involved study designs with administration of bioengineered IL-27/IL-27RA homologs. Whereas many reports have described that IL-27 suppresses inflammation, we also review the current literature, suggesting promotion of inflammation by IL-27 in some settings. Recent advances have also been made in understanding the cross-talk of cleavage products of the complement system with IL-27-mediated immune responses. Additional data on IL-27 have been obtained recently by observational studies in human patients with acute and chronic inflammatory diseases. Collectively, the findings from the past decade identify IL-27 as a critical immunoregulatory cytokine, especially for T cells, whereas some controversy is fueled by results challenging the view of IL-27 as a classical silencer of inflammation.

Paraoxonase-1 suppresses experimental colitis via the inhibition of IFN-γ production from CD4 T cells

Crohn's disease (CD) is a chronic inflammatory disorder of the gastrointestinal tract, where excessive Th1 cell responses are observed. We performed experiments to identify immunologically bioactive proteins in human plasma and found that paraoxonase (PON)-1, which has esterase activity and is associated with high-density lipoproteins, inhibited the IFN-γ production by both murine and human differentiating Th1 cells. Trinitrobenzene sulfonic acid-induced colitis was attenuated by the administration of PON-1. The beneficial effects of PON-1 were associated with a reduced ratio of IFN-γ-producing CD4 T cells in the mesenteric lymph nodes and decreased production of T cell-related cytokines in the colon. PON-1 inhibited the TCR-induced activation of ERK-MAPK signaling and the nuclear translocation of NF-κB in CD4 T cells. Interestingly, an excessive CD4 T cell response was observed in PON-1-deficient mice under physiological and pathological conditions. Additionally, the efficacy of PON-1 or G3C9-C284A (G3C9), which shows a higher esterase activity than PON-1, on colitis was similar to that of an anti-TNF-α mAb, which is a clinically used CD treatment. Moreover, G3C9 more effectively suppressed CD4(+)CD45RB(high) cell transfer-induced chronic colitis in mice than did PON-1, and the efficacy of G3C9 against the colitis was similar to that of the anti-TNF-α mAb. Therefore, PON-1 (or G3C9) administration may be clinically beneficial for CD patients.

Regulation of the expression of Th17 cells and regulatory T cells by IL-27 in patients with unexplained early recurrent miscarriage

In normal pregnancy, tolerance of the maternal immune system with regard to the genetically incompatible fetus depends on the interactions of an array of cytokines secreted by maternal and fetal cells at the site of implantation. Earlier research indicating that altered immunity exists in unexplained recurrent miscarriage (RM) has been dominated by the Th1/Th2 hypothesis. Recently, the Th1/Th2 paradigm has been expanded into the Th1/Th2/Th17 and regulatory T cells paradigm. We recently demonstrated a prevalence of Th17 cells, an inverse relationship between Th17 cells and regulatory T cells and deregulation of Th17 cells by regulatory T cells in early pregnancy in unexplained RM patients. In this study, we investigated the expression of IL-27 and the role of the cytokine IL-27 in the regulation of Th17/Treg expression. Quantitative real-time RT-PCR and Western blot analyses were performed to evaluate IL-27 expression in deciduas from unexplained RM patients, spontaneous miscarriage (SM) patients and healthy women following elective abortion in the early stages of normal pregnancy (control). Regulation of IL-17, TGF-β and IL-10 expression in CD4(+) T cells in unexplained RM patients by IL-27 was assessed using enzyme-linked immunosorbent assay (ELISA). Expression of IL-27 was lower in deciduas of patients with unexplained RM compared with SM and control subjects. IL-27 inhibited IL-17 expression and enhanced IL-10 expression in a dose-dependent manner. IL-27 had no effect on TGF-β expression. IL-27 regulates the expression of IL-17 and IL-10, which are predominantly secreted by Th17 cells and regulatory T cells in unexplained RM patients.

Interleukin-27: balancing protective and pathological immunity

It has been more than 15 years since the identification of individual interleukin-27 (IL-27) and IL-27 receptor components. The last decade has seen the description of the signaling pathways engaged by IL-27, and an appreciation has emerged that this cytokine can modulate the intensity and duration of many classes of T cell responses. Here we provide an overview of the immunobiology of IL-27 and review advances in understanding the functions of individual IL-27 and IL-27 receptor subunits and the role of IL-27 in dictating the balance between protective and pathological immunity. Additionally, this cytokine has been proposed as a therapy to modify inflammatory conditions or to promote antitumor responses, and situations where experimental and clinical data sets implicate IL-27 in the outcome of disease are highlighted.