High susceptibility to liver injury in IL-27 p28 conditional knockout mice involves intrinsic interferon-γ dysregulation of CD4+ T cells

Metabolic Reprogramming of CD4+ T Cells by Mesenchymal Stem Cell-Derived Extracellular Vesicles Attenuates Autoimmune Hepatitis Through Mitochondrial Protein Transfer

Background

Autoimmune hepatitis (AIH) is a serious liver disease characterized by immune disorders, particularly effector T-cell overactivation. This study aimed to explore the therapeutic effect and underlying mechanism of mesenchymal stem cell-derived extracellular vesicle (MSC-EV) treatment on CD4+ T-cell overactivation and liver injury in AIH.

Methods

The metabolic changes of CD4+ T cells were assayed in human AIH and mouse hepatitis models. The liver protective effect of MSC-EVs was evaluated by transaminase levels, liver histopathology and inflammation. The effect of MSC-EVs on the metabolic state of CD4+ T cells was also explored.

Results

Enhanced glycolysis (eg, ~1.5-fold increase in hexokinase 2 levels) was detected in the CD4+ T cells of AIH patient samples and mouse hepatitis models, whereas the inhibition of glycolysis decreased CD4+ T-cell activation (~1.8-fold decrease in CD69 levels) and AIH liver injury (~6-fold decrease in aminotransferase levels). MSC-EV treatment reduced CD4+ T-cell activation (~1.5-fold decrease in CD69 levels) and cytokine release (~5-fold decrease in IFN-γ levels) by reducing glycolysis (~3-fold decrease) while enhancing mitochondrial oxidative phosphorylation (~2-fold increase in maximal respiration) in such cells. The degree of liver damage in AIH mice was ameliorated after MSC-EV treatment (~5-fold decrease in aminotransferase levels). MSC-EVs carried abundant mitochondrial proteins and might transfer them to metabolically reprogram CD4+ T cells, whereas disrupting mitochondrial transfer impaired the therapeutic potency of MSC-EVs in activated CD4+ T cells.

Conclusion

Disordered glucose metabolism promotes CD4+ T-cell activation and associated inflammatory liver injury in AIH models, which can be reversed by MSC-EV therapy, and this effect is at least partially dependent on EV-mediated mitochondrial protein transfer between cells. This study highlights that MSC-EV therapy may represent a new avenue for treating autoimmune diseases such as AIH.

Endogenous IL-27 during toxoplasmosis limits early monocyte responses and their inflammatory activation by pathological T cells

Mice that lack the genes for IL-27, or the IL-27 receptor, and infected with Toxoplasma gondii develop T cell-mediated pathology. Here, studies were performed to determine the impact of endogenous IL-27 on the immune response to T. gondii in wild-type (WT) mice. Analysis of infected mice revealed the early production of IL-27p28 by a subset of Ly6Chi, inflammatory monocytes, and sustained IL-27p28 production at sites of acute and chronic infection. Administration of anti-IL-27p28 prior to infection resulted in an early (day 5) increase in levels of macrophage and granulocyte activation, as well as enhanced effector T cell responses, as measured by both cellularity, cytokine production, and transcriptional profiling. This enhanced acute response led to immune pathology, while blockade during the chronic phase of infection resulted in enhanced T cell responses but no systemic pathology. In the absence of IL-27, the enhanced monocyte responses observed at day 10 were a secondary consequence of activated CD4+ T cells. Thus, in WT mice, IL-27 has distinct suppressive effects that impact innate and adaptive immunity during different phases of this infection.

IMPORTANCE

The molecule IL-27 is critical in limiting the immune response to the parasite Toxoplasma gondii. In the absence of IL-27, a lethal, overactive immune response develops during infection. However, when exactly in the course of infection this molecule is needed was unclear. By selectively inhibiting IL-27 during this parasitic infection, we discovered that IL-27 was only needed during, but not prior to, infection. Additionally, IL-27 is only needed in the active areas in which the parasite is replicating. Finally, our work found that a previously unstudied cell type, monocytes, was regulated by IL-27, which contributes further to our understanding of the regulatory networks established by this molecule.

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.

IL-27p28 specifically regulates MHC II expression in macrophages through CIITA

Antigen-presenting cells (APCs) constantly express major histocompatibility complex II (MHC II), including macrophages and dendritic cells (DCs) which deliver antigens to CD4+ T cells and play an important role in adaptive immunity. The expression of MHC II is controlled by the transcriptional coactivator CIITA. Interleukin-27 (IL-27), a newly discovered IL-12 family cytokine, is composed of p28 and EBI3 subunits. In this study, we used IL-27p28 conditional knock-out mice to investigate the regulatory effects of IL-27p28 on macrophage polarization and the expression of MHC II in macrophages. We found that MHC II expression was upregulated in the bone marrow-derived and peritoneal exudate macrophages (BMDMs; PEMs) from IL-27p28-deficient mice, with their inflammation regulating function unaffected. We also demonstrated that in the APCs, IL-27p28 selectively regulated MHC II expression in macrophages but not in dendritic cells. During Pseudomonas aeruginosa (P. aeruginosa) reinfection, higher survival rate, bacterial clearance, and ratio of CD4+/CD8+ T cells in the spleen during the specific immune phase were observed in IL-27p28 defect mice, as well as an increased MHC II expression in alveolar macrophages (AMs). But these did not occur in the first infection. For the first time we discovered that IL-27p28 specifically regulates the expression of MHC II in macrophages by regulating CIITA, while its absence enhances antigen presentation and adaptive immunity against P. aeruginosa.

IL-27p28 knockout aggravates Doxorubicin-induced cardiotoxicity by regulating Macrophage polarization

BACKGROUND

Several interleukins (ILs) have been demonstrated to participate in cardiac injury. This study aimed to investigate whether IL-27p28 plays a regulatory role in doxorubicin (DOX)-induced cardiac injury by regulating inflammation and oxidative stress.

METHODS

Dox was used to establish a mouse cardiac injury model, and IL-27p28 was knocked out to observe its role in cardiac injury. In addition, monocytes were adoptively transferred to clarify whether monocyte-macrophages mediate the regulatory role of IL-27p28 in DOX-induced cardiac injury.

RESULTS

IL-27p28 knockout significantly aggravated DOX-induced cardiac injury and cardiac dysfunction. IL-27p28 knockout also upregulated the phosphorylation levels of p65 and STAT1 and promoted M1 macrophage polarization in DOX-treated mice, which increased cardiac inflammation and oxidative stress. Moreover, IL-27p28-knockout mice that were adoptively transferred WT monocytes exhibited worse cardiac injury and cardiac dysfunction and higher cardiac inflammation and oxidative stress.

CONCLUSIONS

IL-27p28 knockdown aggravates DOX-induced cardiac injury by worsening the M1 macrophage/M2 macrophage imbalance and its associated inflammatory response and oxidative stress.

Selective IL-27 production by intestinal regulatory T cells permits gut-specific regulation of Th17 immunity

Regulatory T (Treg) cells are instrumental in establishing immunological tolerance. However, the precise effector mechanisms by which Treg cells control a specific type of immune response in a given tissue remains unresolved. By simultaneously studying Treg cells from different tissue origins under systemic autoimmunity, here we show that IL-27 is specifically produced by intestinal Treg cells to regulate Th17 immunity. Selectively increased intestinal Th17 responses in mice with Treg cell-specific IL-27 ablation led to exacerbated intestinal inflammation and colitis-associated cancer, but also helped protect against enteric bacterial infection. Furthermore, single-cell transcriptomic analysis has identified a CD83+TCF1+ Treg cell subset that is distinct from previously characterized intestinal Treg cell populations as the main IL-27 producers. Collectively, our study uncovers a novel Treg cell suppression mechanism crucial for controlling a specific type of immune response in a particular tissue, and provides further mechanistic insights into tissue-specific Treg cell-mediated immune regulation.

Cell type specific IL-27p28 (IL-30) deletion in mice uncovers an unexpected regulatory function of IL-30 in autoimmune inflammation

IL-27 is an IL-12 family cytokine with immune regulatory properties, capable of modulating inflammatory responses, including autoimmunity. While extensive studies investigated the major target cells of IL-27 mediating its functions, the source of IL-27 especially during tissue specific autoimmune inflammation has not formally been examined. IL-27p28 subunit, also known as IL-30, was initially discovered as an IL-27-specific subunit, and it has thus been deemed as a surrogate marker to denote IL-27 expression. However, IL-30 can be secreted independently of Ebi3, a subunit that forms bioactive IL-27 with IL-30. Moreover, IL-30 itself may act as a negative regulator antagonizing IL-27. In this study, we exploited various cell type specific IL-30-deficient mouse models and examined the source of IL-30 in a T cell mediated autoimmune neuroinflammation. We found that IL-30 expressed by infiltrating and CNS resident APC subsets, infiltrating myeloid cells and microglia, is central in limiting the inflammation. However, dendritic cell-derived IL-30 was dispensable for the disease development. Unexpectedly, in cell type specific IL-30 deficient mice that develop severe EAE, IL-30 expression in the remaining wild-type APC subsets is disproportionately increased, suggesting that increased endogenous IL-30 production may be involved in the severe pathogenesis. In support, systemic recombinant IL-30 administration exacerbates EAE severity. Our results demonstrate that dysregulated endogenous IL-30 expression may interfere with immune regulatory functions of IL-27, promoting encephalitogenic inflammation in vivo.

Low-Dose Colchicine Attenuates Sepsis-Induced Liver Injury: A Novel Method for Alleviating Systemic Inflammation

Sepsis is a significant public health challenge. The immune system underlies the pathogenesis of the disease. The liver is both an active player and a target organ in sepsis. Targeting the gut immune system using low-dose colchicine is an attractive method for alleviating systemic inflammation in sepsis without inducing immunosuppression. The present study aimed to determine the use of low-dose colchicine in LPS-induced sepsis in mice. C67B mice were injected intraperitoneal with LPS to induce sepsis. The treatment group received 0.02 mg/kg colchicine daily by gavage. Short and extended models were performed, lasting 3 and 5 days, respectively. We followed the mice for biochemical markers of end-organ injury, blood counts, cytokine levels, and liver pathology and conducted proteomic studies on liver samples. Targeting the gut immune system using low-dose colchicine improved mice's well-being measured by the murine sepsis score. Treatment alleviated the liver injury in septic mice, manifested by a significant decrease in their liver enzyme levels, including ALT, AST, and LDH. Treatment exerted a trend to reduce creatinine levels. Low-dose colchicine improved liver pathology, reduced inflammation, and reduced the pro-inflammatory cytokine TNFα and IL1-β levels. A liver proteomic analysis revealed low-dose colchicine down-regulated sepsis-related proteins, alpha-1 antitrypsin, and serine dehydratase. Targeting the gut immune system using low-dose colchicine attenuated liver injury in LPS-induced sepsis, reducing the pro-inflammatory cytokine levels. Low-dose colchicine provides a safe method for immunomodulation for multiple inflammatory disorders.

Dendritic cell-derived IL-27 p28 regulates T cell program in pathogenicity and alleviates acute graft-versus-host disease

Interleukin 27 (IL-27), a heterodimeric cytokine composed of Epstein-Barr virus-induced 3 and p28, is a pleiotropic cytokine with both pro-and anti-inflammatory properties. However, the precise role of IL-27 in acute graft-versus-host disease is not yet fully understood. In this study, utilizing mice with IL-27 p28 deficiency in dendritic cells (DCs), we demonstrated that IL-27 p28 deficiency resulted in impaired Treg cell function and enhanced effector T cell responses, corresponding to aggravated aGVHD in mice. In addition, using single-cell RNA sequencing, we found that loss of IL-27 p28 impaired Treg cell generation and promoted IL-1R2⁺TIGIT⁺ pathogenic CD4⁺ T cells in the thymus at a steady state. Mechanistically, IL-27 p28 deficiency promoted STAT1 phosphorylation and Th1 cell responses, leading to the inhibition of Treg cell differentiation and function. Finally, patients with high levels of IL-27 p28 in serum showed a substantially decreased occurrence of grade II-IV aGVHD and more favorable overall survival than those with low levels of IL-27 p28. Thus, our results suggest a protective role of DC-derived IL-27 p28 in the pathogenesis of aGVHD through modulation of the Treg/Teff cell balance during thymic development. IL-27 p28 may be a valuable marker for predicting aGVHD development after transplantation in humans.

Conventional and pathogenic Th2 cells in inflammation, tissue repair, and fibrosis

Type 2 helper T (Th2) cells, a subset of CD4⁺ T cells, play an important role in the host defense against pathogens and allergens by producing Th2 cytokines, such as interleukin-4 (IL-4), IL-5, and IL-13, to trigger inflammatory responses. Emerging evidence reveals that Th2 cells also contribute to the repair of injured tissues after inflammatory reactions. However, when the tissue repair process becomes chronic, excessive, or uncontrolled, pathological fibrosis is induced, leading to organ failure and death. Thus, proper control of Th2 cells is needed for complete tissue repair without the induction of fibrosis. Recently, the existence of pathogenic Th2 (Tpath2) cells has been revealed. Tpath2 cells produce large amounts of Th2 cytokines and induce type 2 inflammation when activated by antigen exposure or tissue injury. In recent studies, Tpath2 cells are suggested to play a central role in the induction of type 2 inflammation whereas the role of Tpath2 cells in tissue repair and fibrosis has been less reported in comparison to conventional Th2 cells. In this review, we discuss the roles of conventional Th2 cells and pathogenic Th2 cells in the sequence of tissue inflammation, repair, and fibrosis.

Bacteroides acidifaciens in the gut plays a protective role against CD95-mediated liver injury

The intestinal flora plays an important role in the development of many human and animal diseases. Microbiome association studies revealed the potential regulatory function of intestinal bacteria in many liver diseases, such as autoimmune hepatitis, viral hepatitis and alcoholic hepatitis. However, the key intestinal bacterial strains that affect pathological liver injury and the underlying functional mechanisms remain unclear. We found that the gut microbiota from gentamycin (Gen)-treated mice significantly alleviated concanavalin A (ConA)-induced liver injury compared to vancomycin (Van)-treated mice by inhibiting CD95 expression on the surface of hepatocytes and reducing CD95/CD95L-mediated hepatocyte apoptosis. Through the combination of microbiota sequencing and correlation analysis, we isolated 5 strains with the highest relative abundance, Bacteroides acidifaciens (BA), Parabacteroides distasonis (PD), Bacteroides thetaiotaomicron (BT), Bacteroides dorei (BD) and Bacteroides uniformis (BU), from the feces of Gen-treated mice. Only BA played a protective role against ConA-induced liver injury. Further studies demonstrated that BA-reconstituted mice had reduced CD95/CD95L signaling, which was required for the decrease in the L-glutathione/glutathione (GSSG/GSH) ratio observed in the liver. BA-reconstituted mice were also more resistant to alcoholic liver injury. Our work showed that a specific murine intestinal bacterial strain, BA, ameliorated liver injury by reducing hepatocyte apoptosis in a CD95-dependent manner. Determination of the function of BA may provide an opportunity for its future use as a treatment for liver disease.

B cell-derived IL-27 promotes control of persistent LCMV infection

Recent studies have identified a critical role for B cell-produced cytokines in regulating both humoral and cellular immunity. Here, we show that B cells are an essential source of interleukin-27 (IL-27) during persistent lymphocytic choriomeningitis virus (LCMV) clone 13 (Cl-13) infection. By using conditional knockout mouse models with specific IL-27p28 deletion in B cells, we observed that B cell-derived IL-27 promotes survival of virus-specific CD4 T cells and supports functions of T follicular helper (Tfh) cells. Mechanistically, B cell-derived IL-27 promotes CD4 T cell function, antibody class switch, and the ability to control persistent LCMV infection. Deletion of IL-27ra in T cells demonstrated that T cell-intrinsic IL-27R signaling is essential for viral control, optimal CD4 T cell responses, and antibody class switch during persistent LCMV infection. Collectively, our findings identify a cellular mechanism whereby B cell-derived IL-27 drives antiviral immunity and antibody responses through IL-27 signaling on T cells to promote control of LCMV Cl-13 infection.

Spred2 controls the severity of Concanavalin A-induced liver damage by limiting interferon-gamma production by CD4+ and CD8+ T cells

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Spred2^-/- mice developed exacerbated Con A-induced liver damage with increased IFNγ production.

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MEK/ERK inhibitor U0126 markedly inhibited the damage and reduced IFNγ production.

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Neutralization of IFNγ abolished the damage with down-regulated hepatic STAT1 activation.

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Depletion of CD4⁺/CD8⁺ T cells improved the damage with decreased IFNγ production.

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Transplantation of CD4⁺/CD8⁺ T cells into RAG1^-/- mice reproduced severe liver damage.

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Liver damage and IFNγ production were significantly lower in Spred2 transgenic mice.

Introduction

Mitogen-activated protein kinases (MAPKs) are involved in T cell-mediated liver damage. However, the inhibitory mechanism(s) that controls T cell-mediated liver damage remains unknown.

Objectives

We investigated whether Spred2 (Sprouty-related, EVH1 domain-containing protein 2) that negatively regulates ERK-MAPK pathway has a biological impact on T cell-mediated liver damage by using a murine model.

Methods

We induced hepatotoxicity in genetically engineered mice by intravenously injecting Concanavalin A (Con A) and analyzed the mechanisms using serum chemistry, histology, ELISA, qRT-PCR, Western blotting and flow cytometry.

Results

Spred2-deficient mice (Spred2^-/-) developed more sever liver damage than wild-type (WT) mice with increased interferon-γ (IFNγ) production. Hepatic ERK phosphorylation was enhanced in Spred2^-/- mice, and pretreatment of Spred2^-/- mice with the MAPK/ERK inhibitor U0126 markedly inhibited the liver damage and reduced IFNγ production. Neutralization of IFNγ abolished the damage with decreased hepatic Stat1 activation in Spred2^-/- mice. IFNγ was mainly produced from CD4⁺ and CD8⁺ T cells, and their depletion decreased liver damage and IFNγ production. Transplantation of CD4⁺ and/or CD8⁺ T cells from Spred2^-/- mice into RAG1^-/- mice deficient in both T and B cells caused more severe liver damage than those from WT mice. Hepatic expression of T cell attractants, CXCL9 and CXCL10, was augmented in Spred2^-/- mice as compared to WT mice. Conversely, liver damage, IFNγ production and the recruitment of CD4⁺ and CD8⁺ T cells in livers after Con A challenge were lower in Spred2 transgenic mice, and Spred2-overexpressing CD4⁺ and CD8⁺ T cells produced lower levels of IFNγ than WT cells upon stimulation with Con A in vitro.

Conclusion

We demonstrated, for the first time, that Spred2 functions as an endogenous regulator of T cell IFNγ production and Spred2-mediated inhibition of ERK-MAPK pathway may be an effective remedy for T cell-dependent liver damage.

IL-27 signalling promotes adipocyte thermogenesis and energy expenditure

Thermogenesis in brown and beige adipose tissue has important roles in maintaining body temperature and countering the development of metabolic disorders such as obesity and type 2 diabetes1,2. Although much is known about commitment and activation of brown and beige adipose tissue, its multiple and abundant immunological factors have not been well characterized3-6. Here we define a critical role of IL-27-IL-27Rα signalling in improving thermogenesis, protecting against diet-induced obesity and ameliorating insulin resistance. Mechanistic studies demonstrate that IL-27 directly targets adipocytes, activating p38 MAPK-PGC-1α signalling and stimulating the production of UCP1. Notably, therapeutic administration of IL-27 ameliorated metabolic morbidities in well-established mouse models of obesity. Consistently, individuals with obesity show significantly decreased levels of serum IL-27, which can be restored after bariatric surgery. Collectively, these findings show that IL-27 has an important role in orchestrating metabolic programs, and is a highly promising target for anti-obesity immunotherapy.

IL-27 Derived From Macrophages Facilitates IL-15 Production and T Cell Maintenance Following Allergic Hypersensitivity Responses

Crosstalk between T cells, dendritic cells, and macrophages in temporal leukocyte clusters within barrier tissues provides a new concept for T cell activation in the skin. Activated T cells from these leukocyte clusters play critical roles in the efferent phase of allergic contact hypersensitivity (CHS). However, the cytokines driving maintenance and survival of pathogenic T cells during and following CHS remain mostly unknown. Upon epicutaneous allergen challenge, we here report that macrophages produce IL-27 which then induces IL-15 production from epidermal keratinocytes and dermal myeloid cells within leukocyte clusters. In agreement with the known role of IL-15 as a T cell survival factor and growth cytokine, this signaling axis enhances BCL2 and survival of skin T cells. Genetic depletion or pharmacological blockade of IL-27 in CHS mice leads to abrogated epidermal IL-15 production resulting in a decrease in BCL2 expression in T cells and a decline in dermal CD8⁺ T cells and T cell cluster numbers. These findings suggest that the IL-27 pathway is an important cytokine for regulating cutaneous T cell immunity.

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.

Interleukin-30 Suppresses Not Only CD4+ T Cells but Also Regulatory T Cells in Murine Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic liver autoimmune disease with augmented T helper (Th) 1 and corresponding cytokine IFN-γ immune responses. Using 2-octynoic acid (2-OA) coupled to OVA (2-OA-OVA)-induced mouse models of autoimmune cholangitis (inducible chemical xenobiotic models of PBC), our previous study demonstrated that overexpression of IFN-γ in the model mice enhanced liver inflammation upon disease initiation, but subsequently led to the suppression of chronic inflammation with an increase in interleukin-30 (IL-30) levels. In this study, we investigated whether IL-30 had an immunosuppressive function and whether it could be part of an immune therapeutic regimen for PBC, by treating model mice with murine IL-30-expressing recombinant adeno-associated virus (AAV-mIL-30). We first defined the effects of AAV-mIL-30 in vivo by administering it to a well-known concanavalin A (ConA)-induced hepatitis model of mice and found that AAV-mIL-30 reduced the numbers of activated CD25⁺CD4⁺ T cells and the levels of serum IFN-γ and IL-12. In autoimmune cholangitis, decreased numbers of activated CD4⁺ T cells and Foxp3⁺ regulatory T cells were noted in the mice treated with AAV-mIL-30 at 3 weeks after the 2-OA-OVA immunization. Treatment with IL-30 did not change the features of autoimmune cholangitis including autoantibodies, cell infiltration, and collagen deposition in the liver at 11 weeks of examination. However, increased levels of cytokines and chemokines were observed. These results suggest that IL-30 suppresses not only CD4⁺ T cells but also regulatory T cells. Additionally, the administration of IL-30 did not suppress liver inflammation in the murine model of PBC.

C/EBPα/miR-7 Controls CD4+ T-Cell Activation and Function and Orchestrates Experimental Autoimmune Hepatitis in Mice

BACKGROUND AND AIMS

Increasing evidence in recent years has suggested that microRNA-7 (miR-7) is an important gene implicated in the development of various diseases including HCC. However, the role of miR-7 in autoimmune hepatitis (AIH) is unknown.

APPROACH AND RESULTS

Herein, we showed that miR-7 deficiency led to exacerbated pathology in Concanavalin-A-induced murine acute autoimmune liver injury (ALI) model, accompanied by hyperactivation state of CD4⁺ T cells. Depletion of CD4⁺ T cells reduced the effect of miR-7 deficiency on the pathology of ALI. Interestingly, miR-7 deficiency elevated CD4⁺ T-cell activation, proliferation, and cytokine production in vitro. Adoptive cell transfer experiments showed that miR-7^def CD4⁺ T cells could exacerbate the pathology of ALI. Further analysis showed that miR-7 expression was up-regulated in activated CD4⁺ T cells. Importantly, the transcription of pre-miR-7b, a major resource of mature miR-7 in CD4⁺ T cells, was dominantly dependent on transcription factor CCAAT enhancer binding protein alpha (C/EBPα), which binds to the core promoter region of the miR-7b gene. Global gene analysis showed that mitogen-activated protein kinase 4 (MAPK4) is a target of miR-7 in CD4⁺ T cells. Finally, the loss of MAPK4 could ameliorate the activation state of CD4⁺ T cells with or without miR-7 deficiency. Our studies document the important role of miR-7 in the setting of AIH induced by Concanavalin-A. Specifically, we provide evidence that the C/EBPα/miR-7 axis negatively controls CD4⁺ T-cell activation and function through MAPK4, thereby orchestrating experimental AIH in mice.

CONCLUSIONS

This study expands on the important role of miR-7 in liver-related diseases and reveals the value of the C/EBPα/miR-7 axis in CD4⁺ T-cell biological function for the pathogenesis of immune-mediated liver diseases.

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.

IL-30† (IL-27A): a familiar stranger in immunity, inflammation, and cancer

Over the years, interleukin (IL)-27 has received much attention because of its highly divergent, sometimes even opposing, functions in immunity. IL-30, the p28 subunit that forms IL-27 together with Ebi3 and is also known as IL-27p28 or IL-27A, has been considered a surrogate to represent IL-27. However, it was later discovered that IL-30 can form complexes with other protein subunits, potentially leading to overlapping or discrete functions. Furthermore, there is emerging evidence that IL-30 itself may perform immunomodulatory functions independent of Ebi3 or other binding partners and that IL-30 production is strongly associated with certain cancers in humans. In this review, we will discuss the biology of IL-30 and other IL-30-associated cytokines and their functions in inflammation and cancer.

Studying the ways that interleukin IL-30 regulates immune responses may provide novel insights into tumor development and inflammatory conditions. Interleukins are a diverse family of proteins involved in intercellular communications and immunity, where they can exert divergent and even opposing functions. Booki Min at Northwestern University in Chicago, USA, and co-workers reviewed the current understanding of IL-30 and its links to inflammation and cancer. IL-30 forms the IL-27 complex with the Ebi3 protein and was thought to be a surrogate for IL-27 in terms of activity. However, recent insights suggest that IL-30 may perform discrete immune modulation functions. Elevated IL-30 secretion is linked to prostate and breast cancer development. Extensive research is needed into the formation of IL-30, its associated protein interactions, and the development of a suitable animal model.

CD40 Agonist Overcomes T Cell Exhaustion Induced by Chronic Myeloid Cell IL-27 Production in a Pancreatic Cancer Preclinical Model

Pancreatic cancer is a particularly lethal malignancy that resists immunotherapy. In this study, using a preclinical pancreatic cancer murine model, we demonstrate a progressive decrease in IFN-γ and granzyme B and a concomitant increase in Tox and IL-10 in intratumoral tumor-specific T cells. Intratumoral myeloid cells produced elevated IL-27, a cytokine that correlates with poor patient outcome. Abrogating IL-27 signaling significantly decreased intratumoral Tox⁺ T cells and delayed tumor growth yet was not curative. Agonistic αCD40 decreased intratumoral IL-27-producing myeloid cells, decreased IL-10-producing intratumoral T cells, and promoted intratumoral Klrg1⁺Gzmb⁺ short-lived effector T cells. Combination agonistic αCD40+αPD-L1 cured 63% of tumor-bearing animals, promoted rejection following tumor rechallenge, and correlated with a 2-log increase in pancreas-residing tumor-specific T cells. Interfering with Ifngr1 expression in nontumor/host cells abrogated agonistic αCD40+αPD-L1 efficacy. In contrast, interfering with nontumor/host cell Tnfrsf1a led to cure in 100% of animals following agonistic αCD40+αPD-L1 and promoted the formation of circulating central memory T cells rather than long-lived effector T cells. In summary, we identify a mechanistic basis for T cell exhaustion in pancreatic cancer and a feasible clinical strategy to overcome it.

IL-21-Deficient T Follicular Helper Cells Support B Cell Responses Through IL-27 in Patients With Chronic Hepatitis B

Chronic Hepatitis B (CHB) affects over 350 million people worldwide. Current treatment does result in reduced complications; however, a cure (development of antibodies to the S antigen) is not achieved, requiring life-long therapy. Humoral responses contribute to viral elimination by secreting neutralizing antibodies; though, effective induction of humoral immunity require CD4T cell differentiation into T follicular helper (T_FH) cells that support B cell response through interleukin-21 (IL-21). In CHB, mechanism of T_FH-B interactions is seldom described. During CHB, T_FH cells are defective in producing IL-21 in response to hepatitis B surface antigen (HBsAg). However, regardless of low IL-21, T_FH cells efficiently support B cell responses by producing interleukin-27 (IL-27), which directs the formation of plasmablasts and plasma cells from memory and naïve B cells by enhancing B lymphocyte-induced maturation protein-1. IL-27 not only improved total antibody production but HBsAg-specific IgG and IgM secretion that are essential for viral clearance. Importantly, IL-27+T_FH cells were significantly associated with HBV DNA reduction. Therefore, these findings imply a novel mechanism of T_FH mediated B cell help in CHB and suggest that IL-27 effectively compensate the function of IL-21 by supporting T_FH-B cell function, required for protective antibody response and may contribute to viral clearance by providing potential target for achieving a functional cure.

Activation of Liver X Receptor α Sensitizes Mice to T-Cell Mediated Hepatitis

Autoimmune hepatitis (AIH) is an inflammatory disease of the liver. Liver X receptors (LXRs), including the α and β isoforms, are previously known for their anti-inflammatory activities. The goal of this study is to determine whether and how LXR plays a role in AIH. LXRα gain-of-function and loss-of-function mouse models were used, in conjunction with the concanavalin A (ConA) model of T-cell mediated hepatitis. We first showed that the hepatic expression of LXRα was decreased in the ConA model of hepatitis and in human patients with AIH. In the ConA model, we were surprised to find that activation of LXRα in the constitutively activated VP-LXRα whole-body knock-in (LXRα-KI) mice exacerbated ConA-induced AIH, whereas the LXRα-/- mice showed attenuated ConA-induced AIH. Interestingly, hepatocyte-specific activation of LXRα in the fatty acid binding protein-VP-LXRα transgenic mice did not exacerbate ConA-induced hepatitis. Mechanistically, the sensitizing effect of the LXRα-KI allele was invariant natural killer T (iNKT)-cell dependent, because the sensitizing effect was abolished when the LXRα-KI allele was bred into the NKT-deficient CD1d-/- background. In addition, LXRα-enhanced ConA-induced hepatitis was dependent on interferon gamma. In contrast, adoptive transfer of hepatic iNKT cells isolated from LXRα-KI mice was sufficient to sensitize CD1d-/- mice to ConA-induced AIH. Conclusion: Activation of LXRα sensitizes mice to ConA-induced AIH in iNKT and interferon gamma-dependent manner. Our results suggest that LXRα plays an important role in the development of AIH.

Interleukin-27 Functional Duality Balances Leishmania Infectivity and Pathogenesis

IL-27 is a cytokine that exerts diverse effects on the cells of innate and adaptive immune systems. Chiefly expressed in macrophages and dendritic cells during the early phase of Leishmania infection, IL-27 contributes to the protection against L. major infection but suppresses the protective Th1 response against L. donovani, L. infantum, L. amazonensis and L. braziliensis infections, suggesting its functional duality. During the late stage of Leishmania infection, IL-27 limits the immunopathogenic reactions and tissue damages. Herein, we analyze the mechanism of the functional duality of IL-27 in the resistance or susceptibility to Leishmania infection, prompting IL-27 for anti-Leishmanial therapy.

T Cells in Fibrosis and Fibrotic Diseases

Fibrosis is the extensive deposition of fibrous connective tissue, and it is characterized by the accumulation of collagen and other extracellular matrix (ECM) components. Fibrosis is essential for wound healing and tissue repair in response to a variety of triggers, which include infection, inflammation, autoimmune disorder, degenerative disease, tumor, and injury. Fibrotic remodeling in various diseases, such as liver cirrhosis, pulmonary fibrosis, renal interstitial fibrosis, myocardial infarction, systemic sclerosis (SSc), and graft-versus-host disease (GVHD), can impair organ function, causing high morbidity and mortality. Both innate and adaptive immunity are involved in fibrogenesis. Although the roles of macrophages in fibrogenesis have been studied for many years, the underlying mechanisms concerning the manner in which T cells regulate fibrosis are not completely understood. The T cell receptor (TCR) engages the antigen and shapes the repertoire of antigen-specific T cells. Based on the divergent expression of surface molecules and cell functions, T cells are subdivided into natural killer T (NKT) cells, γδ T cells, CD8⁺ cytotoxic T lymphocytes (CTL), regulatory T (Treg) cells, T follicular regulatory (Tfr) cells, and T helper cells, including Th1, Th2, Th9, Th17, Th22, and T follicular helper (Tfh) cells. In this review, we summarize the pro-fibrotic or anti-fibrotic roles and distinct mechanisms of different T cell subsets. On reviewing the literature, we conclude that the T cell regulations are commonly disease-specific and tissue-specific. Finally, we provide perspectives on microbiota, viral infection, and metabolism, and discuss the current advancements of technologies for identifying novel targets and developing immunotherapies for intervention in fibrosis and fibrotic diseases.

Perforin Acts as an Immune Regulator to Prevent the Progression of NAFLD

Non-alcoholic fatty liver disease (NAFLD) is one of the main causes of cirrhosis and major risk factors for hepatocellular carcinoma and liver-related death. Despite substantial clinical and basic research, the pathogenesis of obesity-related NAFLD remains poorly understood. In this study, we show that perforin can act as an immune regulator to prevent the progression of NAFLD. Aged perforin-deficient (Prf^−/−) mice have increased lipid accumulation in the liver compared to WT mice. With high-fat diet (HFD) challenge, Prf^−/− mice have increased liver weight, more severe liver damage, and increased liver inflammation when compared with WT controls. Mechanistic studies revealed that perforin specifically regulates intrinsic IFN-γ production in CD4 T cells, not CD8 T cells. We found that CD4 T cell depletion reduces liver injury and ameliorates the inflammation and metabolic morbidities in Prf^−/− mice. Furthermore, improved liver characteristics in HFD Prf^−/− and IFN-γR^−/− double knockout mice confirmed that IFN-γ is a key factor for mediating perforin regulation of NAFLD progression. Overall, our findings reveal the important regulatory role perforin plays in the progression of obesity-related NAFLD and highlight novel strategies for treating NAFLD.

Decoding the Role of Interleukin-30 in the Crosstalk Between Cancer and Myeloid Cells

In the last few years, a new actor hit the scene of the tumor microenvironment, the p28 subunit of interleukin (IL)-27, known as IL-30. Its molecular structure allows it to function as an autonomous cytokine and, alternatively, to pair with other subunits to form heterodimeric complexes and enables it to play different, and not fully elucidated, roles in immunity. However, data from the experimental models and clinical samples, suggest IL-30′s engagement in the relationship between cancer and myeloid cells, which fosters the tumor microenvironment and the cancer stem cell niche, boosting the disease progression. Activated myeloid cells are the primary cellular source and one of the targets of IL-30, which can also be produced by cancer cells, especially, in aggressive tumors, as observed in the breast and prostate. This review briefly reports on the immunobiology of IL-30 and related cytokines, by comparing mouse and human counterparts, and then focuses on the mechanisms whereby IL-30 amplifies intratumoral myeloid cell infiltrate and triggers a vicious cycle that worsens immunosuppression in the tumor microenvironment (TME) and constitutes a real threat for a successful immunotherapeutic strategy.

cDC1 IL-27p28 Production Predicts Vaccine-Elicited CD8+ T Cell Memory and Protective Immunity

Although adjuvants and formulations are often either empirically derived, or at best judged by their ability to elicit broad inflammation, it would be ideal if specific innate correlates of adaptive immunity could be identified to set a universally applicable benchmark for adjuvant evaluation. Using an IL-27 reporter transgenic mouse model, we show in this study that conventional type 1 dendritic cell IL-27 production in the draining lymph node 12 h after s.c. vaccination directly correlates with downstream CD8⁺ T cell memory and protective immunity against infectious challenge. This correlation is robust, reproducible, predictive, entirely unique to vaccine biology, and is the only innate correlate of CD8⁺ T cell immune memory yet to be identified. Our results provide new insights into the basic biology of adjuvant-elicited cellular immunity and have clear implications for the screening and evaluation of novel adjuvants.

Impact of Interleukin-27p28 on T and B Cell Responses during Toxoplasmosis

Interleukin-27 (IL-27) is a heterodimeric cytokine composed of the subunits IL-27p28 and EBi3, and while the IL-27 heterodimer influences T cell activities, there is evidence that IL-27p28 can have EBi3-independent activities; however, their relevance to infection is unclear. Therefore, the studies presented here compared how IL-27p28 transgenics and IL-27p28-/- mice responded to the intracellular parasite Toxoplasma gondii While the loss of IL-27p28 and its overexpression both result in increased susceptibility to T. gondii, the basis for this phenotype reveals distinct roles for IL-27p28. As a component of IL-27, IL-27p28 is critical to limit infection-induced T cell-mediated pathology, whereas the ectopic expression of IL-27p28 reduced the effector T cell population and had a major inhibitory effect on parasite-specific antibody titers and a failure to control parasite replication in the central nervous system. Indeed, transfer of immune serum to infected IL-27p28 transgenics resulted in reduced parasite burden and pathology. Thus, IL-27p28, independent of its role as a component of IL-27, can act as a negative regulator of humoral and cellular responses during toxoplasmosis.

IL-27 is elevated in sepsis with acute hepatic injury and promotes hepatic damage and inflammation in the CLP model

BACKGROUND

Immuno-inflammation plays an important role in the pathophysiological process of sepsis-associated acute hepatic injury (AHI). Interleukin 27 (IL-27) is an important inflammatory regulator; however, its role in this condition is not clear.

METHODS

The clinical data and IL-27 serum levels in sepsis patients with or without AHI were analysed. Classical caecal ligation puncture (CLP) models were established in wild-type (WT) and IL-27 receptor (WSX-1)-deficient (IL-27R^-/-) mice. In addition, exogenous IL-27 was injected into these mice, and the levels of IL-27, IL-6, and tumour necrosis factor alpha (TNF-α) in the serum and liver were then measured by enzyme-linked immunoassay (ELISA), quantitative PCR, and Western blotting. The severity of liver damage was evaluated by haematoxylin and eosin staining of liver tissue, TUNEL assay and evaluation of alanine aminotransferase (ALT) and aspartate transaminase (AST) serum levels. Furthermore, the effects of IL-27 on the levels of phosphorylated c-Jun N-terminal kinase (JNK) in macrophages were assessed by Western blotting, and the effects of IL-27 on the expression of IL-6 and TNF-α in macrophages were assessed by ELISA.

RESULTS

IL-27 was elevated in sepsis patients with acute hepatic injury, which correlated with the Acute Physiologic Assessment and Chronic Health Evaluation II (APACHEII) scores, Sequential Organ Failure Assessment (SOFA) scores, and procalcitonin, C-reactive protein, IL-6, and TNF-α expression. In the CLP-WT group, IL-27 was highly expressed in the serum and liver, which correlated with the elevated content of ALT, AST, TNF-α, IL-6, and p-JNK in the serum and liver and the pathological injury of the liver. In CLP-IL-27R^-/- group, however, the levels of ALT, AST, TNF-α, IL-6, and p-JNK in the serum and liver and the pathological injury of the liver were decreased. Treatment with exogenous IL-27 led to a further increase in these cytokines in WT mice after CLP. IL-27 treatment and lipopolysaccharide stimulation in vitro increased the expression of p-JNK, IL-6, and TNF-α in macrophages, and these changes were decreased by a JNK signalling pathway inhibitor.

CONCLUSION

IL-27 is elevated in sepsis patients, especially those with acute hepatic injury. In addition, IL-27 can promote inflammatory reactions in the CLP-induced hepatic injury mice model.

IL-27, IL-30, and IL-35: A Cytokine Triumvirate in Cancer

The role of the immune system in anti-tumor immunity cannot be overstated, as it holds the potential to promote tumor eradication or prevent tumor cell escape. Cytokines are critical to influencing the immune responses and interactions with non-immune cells. Recently, the IL-12 and IL-6 family of cytokines have accumulated newly defined members each with specific immune functions related to various cancers and tumorigenesis. There is a need to better understand how cytokines like IL-27, IL-30, and IL-35 interact with one another, and how a developing tumor can exploit these interactions to enhance immune suppression. Current cytokine-based immunotherapies are associated with cytotoxic side effects which limits the success of treatment. In addition to this toxicity, understanding the complex interactions between immune and cancer cells may be one of the greatest challenges to developing a successful immunotherapy. In this review, we bring forth IL-27, IL-30, and IL-35, “sister cytokines,” along with more recent additions to the IL-12 family, which serve distinct purposes despite sharing structural similarities. We highlight how these cytokines function in the tumor microenvironment by examining their direct effects on cancer cells as well their indirect actions via regulatory functions of immune cells that act to either instigate or inhibit tumor progression. Understanding the context dependent immunomodulatory outcomes of these sister cytokines, as well as their regulation within the tumor microenvironment, may shed light onto novel cancer therapeutic treatments or targets.

Retinoic acid modulates IL-4, IL-10 and MCP-1 pathways in immune mediated hepatitis and interrupts CD4+ T cells infiltration

AIMS

Immune mediated liver injury includes activation of different immune pathways that requires various modalities to control their consequences. The current study involves evaluation of retinoic acid (RA) modulatory effects on immune responses induced in concanavalin A (ConA) model of acute hepatitis.

MAIN METHODS

Mice were divided as follows: Control group; RA group: received 35 mg/kg RA; ConA group: received 15 mg/kg ConA; ConA + RA group: received ConA and RA as described. Liver function biomarkers were measured in addition to malondialdehyde as lipid peroxidation biomarker. Liver tissue sections were scored for necro-inflammation, neutrophils infiltration, CD4+ T cells infiltration and NF-κb positive cells. Effect on hepatic levels of TNF-α, IL-4, IL-10 and MCP-1 was evaluated as well.

KEY FINDINGS

Injection of RA before ConA significantly (p < 0.001) decreased ALT, AST and LDH levels compared to their levels in ConA group. Hepatic infiltration of neutrophils and CD4+ T cells was markedly (p < 0.001) reduced by RA. Hepatic injury, necrosis and expression of NF-κb were significantly decreased by RA when injected before ConA challenge. A significant decrease in the measured cytokines TNF-α and IL-4 was observed in ConA + RA group in addition to a decrease in MCP-1 level. On the other hand, IL-10 was significantly increased in the latter group compared to ConA group.

SIGNIFICANCE

RA can protect against ConA-induced hepatitis through: interrupting early inflammatory response as neutrophils, monocytes and CD4+ T cells infiltration, modulating IL-4 level and subsequent production of TNF-α and NF-κb activation, mitigating second inflammatory responses through increasing IL-10 liver production.

Targeting Interleukin(IL)-30/IL-27p28 signaling in cancer stem-like cells and host environment synergistically inhibits prostate cancer growth and improves survival

Background

Interleukin(IL)-30/IL-27p28 production by Prostate Cancer (PC) Stem-Like Cells (SLCs) has proven, in murine models, to be critical to tumor onset and progression. In PC patients, IL-30 expression by leukocytes infiltrating PC and draining lymph nodes correlates with advanced disease grade and stage. Here, we set out to dissect the role of host immune cell-derived IL-30 in PC growth and patient outcome.

Methods

PC-SLCs were implanted in wild type (WT) and IL-30 conditional knockout (IL-30KO) mice. Histopathological and cytofluorimetric analyses of murine tumors and lymphoid tissues prompted analyses of patients’ PC samples and follow-ups.

Results

Implantation of PC-SLCs in IL-30KO mice, gave rise to slow growing tumors characterized by apoptotic events associated with CD4⁺T lymphocyte infiltrates and lack of CD4⁺Foxp3⁺ T regulatory cells (Tregs). IL-30 knockdown in PC-SLCs reduced cancer cell proliferation, vascularization and intra-tumoral Indoleamine 2,3-Dioxygenase (IDO)⁺CD11b⁺Gr-1⁺ myeloid-derived cells (MDCs) and led to a significant delay in tumor growth and increase in survival. IL-30-silenced tumors developed in IL-30KO mice, IL-30^−/−tumors, lacked vascular supply and displayed frequent apoptotic cancer cells entrapped by perforin⁺TRAIL⁺CD3⁺Tlymphocytes, most of which had a CD4⁺T phenotype, whereas IL-10⁺TGFβ⁺Foxp3⁺Tregs were lacking. IL-30 silencing in PC-SLCs prevented lung metastasis in 73% of tumor-bearing WT mice and up to 80% in tumor-bearing IL-30KO mice.

In patients with high-grade and locally advanced PC, those with IL-30^−/−tumors, showed distinct intra-tumoral cytotoxic granule-associated RNA binding protein (TIA-1)⁺CD4⁺Tlymphocyte infiltrate, rare Foxp3⁺Tregs and a lower biochemical recurrence rate compared to patients with IL-30^+/+tumors in which IL-30 is expressed in both tumor cells and infiltrating leukocytes.

Conclusion

The lack of host leukocyte-derived IL-30 inhibits Tregs expansion, promotes intra-tumoral infiltration of CD4⁺T lymphocytes and cancer cell apoptosis. Concomitant lack of MDC influx, obtained by IL-30 silencing in PC-SLCs, boosts cytotoxic T lymphocyte activation and cancer cell apoptosis resulting in a synergistic tumor suppression with the prospective benefit of better survival for patients with advanced disease.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0668-z) contains supplementary material, which is available to authorized users.

IL-27 targets Foxp3+ Tregs to mediate antiinflammatory functions during experimental allergic airway inflammation

Foxp3+ CD4 Tregs are central regulators of inflammation, including allergic inflammation in the lung. There is increasing evidence that inflammatory factors undermine adequate Treg functions and homeostasis, resulting in prolonged and exacerbated inflammation. Therefore, identifying the factors is of the utmost important. IL-27 is an antiinflammatory cytokine implicated in immune regulation and tolerance. However, the cellular mechanisms underlying IL-27-mediated immune regulation in vivo remain largely unknown. Utilizing a cockroach antigen-induced allergic inflammation model in mice, we sought to test the roles of Tregs during IL-27-mediated regulation of allergic inflammation. Intranasally delivered IL-27 significantly reduced the development of airway inflammation. Unexpectedly, the IL-27-induced reduction occurred only in the presence of Tregs. Il27ra-/- and Treg-specific Il27ra-/- mice developed severe airway inflammation, and IL-27 treatment had little impact on diminishing the inflammatory responses. IL-27-induced treatment was restored following transfer of WT Tregs but not of Tregs deficient in Lag3, a molecule induced by IL-27 in Tregs. Finally, Tregs from asthmatic patients exhibited blunted STAT1 phosphorylation following IL-27 stimulation. Taken together, our results uncover that Tregs are the primary target cells of IL-27 in vivo to mediate its antiinflammatory functions, suggesting that altered IL-27 responsiveness in Tregs may underlie inadequate Treg functions and perpetuation of inflammation.

Protein kinase p38α signaling in dendritic cells regulates colon inflammation and tumorigenesis

Dendritic cells (DCs) play pivotal roles in maintaining intestinal homeostasis, but how the DCs regulate diverse immune networks on homeostasis breakdown remains largely unknown. Here, we report that, in response to epithelial barrier disruption, colonic DCs regulate the differentiation of type 1 regulatory T (Tr1) cells through p38α-dependent IL-27 production to initiate an effective immune response. Deletion of p38α in DCs, but not in T cells, led to increased Tr1 and protected mice from dextran sodium sulfate-induced acute colitis and chronic colitis-associated colorectal cancer. We show that higher levels of IL-27 in p38α-deficient colonic cDC1s, but not cDC2s, were responsible for the increase of Tr1 cells. Moreover, p38α-dependent IL-27 enhanced IL-22 secretion from intestinal group 3 innate lymphoid cells and protected epithelial barrier function. In p38α-deficient DCs, the TAK1-MKK4/7-JNK-c-Jun axis was hyperactivated, leading to high IL-27 levels, and inhibition of the JNK-c-Jun axis suppressed IL-27 expression. ChIP assay revealed direct binding of c-Jun to the promoter of Il27p28, which was further enhanced in p38α-deficient DCs. In summary, here we identify a key role for p38α signaling in DCs in regulating intestinal inflammatory response and tumorigenesis, and our finding may provide targets for the treatment of inflammatory intestinal diseases.

MiR-29a and miR-652 Attenuate Liver Fibrosis by Inhibiting the Differentiation of CD4+ T Cells

BACKGROUND

Liver fibrosis is the response of liver diseases that puzzles patients. MiRNAs were involved in the regulating processes of liver fibrosis. This study aims to investigate the effects of ARRB1 mediated by miR-29a and miR-652 on liver fibrosis and its possible mechanism.

METHODS

Liver fibrosis of mice was induced by intraperitoneal injection of CCl₄. Liver function was observed by the levels of alanine transaminase (ALT) and aspartate transaminase (AST). Flow cytometry was used to detect the percent of T helper17 (Th17). ELISA (Enzyme linked immunoassay) was used to detect the levels of Interleukin-17 (IL-17) and Interleukin-22 (IL-22). Real-time PCR was used to detect the expression of IL-17A, IL-22, miR-29a, miR-652 and β-Arrestin 1 Gene (ARRB1). Western blot was used to detect the protein expression of ARRB1.

RESULTS

CCl₄ supplementation significantly increased the level of ALT and AST, the percent of Th17, the level of IL-17A, IL-22, miR-29a and miR-652, but decreased ARRB1. Overexpression of miR-29a/miR-652 prominently decreased Th17, IL-17A, IL-22 and ARRB1 in the normal CD4+ T cells. Both miR-29a and miR-652 targeted ARRB1 to regulate its expression. The effects of miR-29a/miR-652 overexpression on CD4+ T cells were reversed by ARRB1 overexpression. In vivo experiments demonstrated the protective role of miR-29a/miR-652 overexpression on liver fibrosis.

CONCLUSION

ARRB1 mediated by miR-29a and miR-652 probably involved in the CD4+ T cells differentiation in patients with liver fibrosis, and functioned as a biomarker of fibrosis liver.Key words: liver fibrosis, miR-29a, miR-652, ARRB1, CD4+ T cells.

IL-27 regulates the number, function and cytotoxic program of antiviral CD4 T cells and promotes cytomegalovirus persistence

The role of IL-27 in antiviral immunity is still incompletely understood, especially in the context of chronic viruses that induce a unique environment in their infected host. Cytomegalovirus (CMV) establishes a persistent, tissue localized infection followed by lifelong latency. CMV infects the majority of people and although asymptomatic in healthy individuals, can cause serious disease or death in those with naïve or compromised immune systems. Therefore, there is an urgent need to develop a protective CMV vaccine for people at-risk and identifying key regulators of the protective immune response towards CMV will be crucial. Here we studied mouse CMV (MCMV) in IL-27 receptor deficient animals (Il27ra-/-) to assess the role of IL-27 in regulating CMV immunity. We found that IL-27 enhanced the number of antiviral CD4 T cells upon infection. However, in contrast to a well-established role for CD4 T cells in controlling persistent replication and a positive effect of IL-27 on their numbers, IL-27 promoted MCMV persistence in the salivary gland. This coincided with IL-27 mediated induction of IL-10 production in CD4 T cells. Moreover, IL-27 reduced expression of the transcription factor T-bet and restricted a cytotoxic phenotype in antiviral CD4 T cells. This is a highly intriguing result given the profound cytotoxic phenotype of CMV-specific CD4 T cells seen in humans and we established that dendritic cell derived IL-27 was responsible for this effect. Together, these data show that IL-27 regulates the number and effector functions of MCMV-specific CD4 T cells and could be targeted to enhance control of persistent/latent infection.

γδ T cells are indispensable for interleukin-23-mediated protection against Concanavalin A-induced hepatitis in hepatitis B virus transgenic mice

Hepatitis B virus surface antigen (HBsAg) carriers are highly susceptible to liver injury triggered by environmental biochemical stimulation. Previously, we have reported an inverse correlation between γδ T cells and liver damage in patients with hepatitis B virus (HBV). However, whether γδ T cells play a role in regulating the hypersensitivity of HBsAg carriers to biochemical stimulation-induced hepatitis is unknown. In this study, using HBV transgenic (HBs-Tg) and HBs-Tg T-cell receptor-δ-deficient (TCR-δ^-/- ) mice, we found that mice genetically deficient in γδ T cells exhibited more severe liver damage upon Concanavalin A (Con A) treatment, as indicated by substantially higher serum alanine aminotransferase levels, further elevated interferon-γ (IFN-γ) levels and more extensive necrosis. γδ T-cell deficiency resulted in elevated IFN-γ in CD4⁺ T cells but not in natural killer or natural killer T cells. The depletion of CD4⁺ T cells and neutralization of IFN-γ reduced liver damage in HBs-Tg and HBs-Tg-TCR-δ^-/- mice to a similar extent. Further investigation revealed that HBs-Tg mice showed an enhanced interleukin-17 (IL-17) signature. The administration of exogenous IL-23 enhanced IL-17A production from Vγ4 γδ T cells and ameliorated liver damage in HBs-Tg mice, but not in HBs-Tg-TCR-δ^-/- mice. In summary, our results demonstrated that γδ T cells played a protective role in restraining Con A-induced hepatitis by inhibiting IFN-γ production from CD4⁺ T cells and are indispensable for IL-23-mediated protection against Con A-induced hepatitis in HBs-Tg mice. These results provided a potential therapeutic approach for treating the hypersensitivity of HBV carriers to biochemical stimulation-induced liver damage.

Prostaglandin E2 Inhibition of IL-27 Production in Murine Dendritic Cells: A Novel Mechanism That Involves IRF1

IL-27, a multifunctional cytokine produced by APCs, antagonizes inflammation by affecting conventional dendritic cells (cDC), inducing IL-10, and promoting development of regulatory Tr1 cells. Although the mechanisms involved in IL-27 induction are well studied, much less is known about the factors that negatively impact IL-27 expression. PGE₂, a major immunomodulatory prostanoid, acts as a proinflammatory agent in several models of inflammatory/autoimmune disease, promoting primarily Th17 development and function. In this study, we report on a novel mechanism that promotes the proinflammatory function of PGE₂ We showed previously that PGE₂ inhibits IL-27 production in murine bone marrow-derived DCs. In this study, we show that, in addition to bone marrow-derived DCs, PGE₂ inhibits IL-27 production in macrophages and in splenic cDC, and we identify a novel pathway consisting of signaling through EP2/EP4→induction of cAMP→downregulation of IFN regulatory factor 1 expression and binding to the p28 IFN-stimulated response element site. The inhibitory effect of PGE₂ on p28 and irf1 expression does not involve endogenous IFN-β, STAT1, or STAT2, and inhibition of IL-27 does not appear to be mediated through PKA, exchange protein activated by cAMP, PI3K, or MAPKs. We observed similar inhibition of il27p28 expression in vivo in splenic DC following administration of dimethyl PGE₂ in conjunction with LPS. Based on the anti-inflammatory role of IL-27 in cDC and through the generation of Tr1 cells, we propose that the PGE₂-induced inhibition of IL-27 in activated cDC represents an important additional mechanism for its in vivo proinflammatory functions.

Critical roles of conventional dendritic cells in promoting T cell-dependent hepatitis through regulating natural killer T cells

Dendritic cells (DCs) play critical roles in initiating and regulating innate immunity as well as adaptive immune responses. However, the role of conventional dendritic cells (cDCs) in concanavalin A (ConA)-induced fulminant hepatitis is unknown. In this study, we demonstrated that depletion of cDCs using either CD11c-diphtheria toxin receptor transgenic mice (DTR Tg) mice or anti-CD11c antibody reduced the severity of liver injury significantly, indicating a detrimental role of cDCs in ConA-induced hepatitis. We elucidated further the pathological role of cDCs as being the critical source of interleukin (IL)-12, which induced the secretion of interferon (IFN)-γ by natural killer (NK) T cells. Reconstitution of cDCs-depleted mice with IL-12 restored ConA-induced hepatitis significantly. Furthermore, we determined that NK T cells were the target of DC-derived IL-12, and NK T cells contributed to liver inflammation and injury through production of IFN-γ. In summary, our study demonstrated a novel function of cDCs in mediating ConA-induced hepatitis through regulating IFN-γ secretion of NK T cells in an IL-12-dependent fashion. Targeting cDCs might provide potentially therapeutic applications in treating autoimmune related liver diseases.

Idiosyncratic Drug-Induced Liver Injury: Is Drug-Cytokine Interaction the Linchpin?

Idiosyncratic drug-induced liver injury continues to be a human health problem in part because drugs that cause these reactions are not identified in current preclinical testing and because progress in prevention is hampered by incomplete knowledge of mechanisms that underlie these adverse responses. Several hypotheses involving adaptive immune responses, inflammatory stress, inability to adapt to stress, and multiple, concurrent factors have been proposed. Yet much remains unknown about how drugs interact with the liver to effect death of hepatocytes. Evidence supporting hypotheses implicating adaptive or innate immune responses in afflicted patients has begun to emerge and is bolstered by results obtained in experimental animal models and in vitro systems. A commonality in adaptive and innate immunity is the production of cytokines, including interferon-γ (IFNγ). IFNγ initiates cell signaling pathways that culminate in cell death or inhibition of proliferative repair. Tumor necrosis factor-α, another cytokine prominent in immune responses, can also promote cell death. Furthermore, tumor necrosis factor-α interacts with IFNγ, leading to enhanced cellular responses to each cytokine. In this short review, we propose that the interaction of drugs with these cytokines contributes to idiosyncratic drug-induced liver injury, and mechanisms by which this could occur are discussed.

Expanding Diversity in Molecular Structures and Functions of the IL-6/IL-12 Heterodimeric Cytokine Family

The interleukin (IL)-6/IL-12 family cytokines have pleiotropic functions and play critical roles in multiple immune responses. This cytokine family has very unique characteristics in that they comprise two distinct subunits forming a heterodimer and each cytokine and receptor subunit shares with each other. The members of this cytokine family are increasing; currently, there are more than six cytokines, including the tentatively named cytokines IL-Y (p28/p40), IL-12 (p35/p40), IL-23 (p19/p40), IL-27 [p28/Epstein–Barr virus-induced protein 3 (EBI3)], IL-35 (p35/EBI3), and IL-39 (p19/EBI3). This family of cytokines covers a very broad range of immune responses, including pro-inflammatory responses, such as helper T (Th)1, Th2, and Th17, to anti-inflammatory responses, such as regulatory T (Treg) cells and IL-10-producing Treg cells. IL-12 is the first member of this family, and IL-12, IL-23, and IL-27 are mainly produced by activated antigen-presenting cells, such as dendritic cells and macrophages. IL-12 plays a critical role in the promotion of Th1 immune responses by inducing interferon-γ production to combat pathogens and malignant tumors. IL-23 induces IL-17 production and is necessary to maintain pathogenic Th17 cells that cause inflammatory and autoimmune diseases. IL-27 was initially reported to play a critical role in promotion of Th1 differentiation; however, subsequent studies revealed that IL-27 has broader stimulatory and inhibitory roles by inducing IL-10-producing Treg cells. IL-35 is produced by forkhead box P3⁺ Treg cells and activated B cells and has immunosuppressive functions to maintain immune tolerance. The most recently identified cytokine, IL-39, is produced by activated B cells and has pro-inflammatory functions. The cytokine tentatively named IL-Y seems to have anti-inflammatory functions by inhibiting Th1 and Th17 differentiation. In addition, individual cytokine subunits were also shown to have self-standing activities. Thus, promiscuity within the IL-6/IL-12 family cytokines complicates structural and functional clarification and assignment of individual cytokines. A better understanding of the recent advances and expanding diversity in molecular structures and functions of the IL-6/IL-12 family cytokines could allow the creation of novel therapeutic strategies by using them as tools and targeted molecules.

Interleukin-27 Early Impacts Leishmania infantum Infection in Mice and Correlates with Active Visceral Disease in Humans

The complexity of Leishmania–host interactions, one of the main leishmaniasis issues, is yet to be fully understood. We detected elevated IL-27 plasma levels in European patients with active visceral disease caused by Leishmania infantum, which returned to basal levels after successful treatment, suggesting this cytokine as a probable infection mediator. We further addressed this hypothesis recurring to two classical susceptible visceral leishmaniasis mouse models. BALB/c, but not C57BL/6 mice, showed increased IL-27 systemic levels after infection, which was associated with an upregulation of IL-27p28 expression by dendritic cells and higher parasite burdens. Neutralization of IL-27 in acutely infected BALB/c led to decreased parasite burdens and a transient increase in IFN-γ⁺ splenic T cells, while administration of IL-27 to C57BL/6 promoted a local anti-inflammatory cytokine response at the site of infection and increased parasite loads. Overall, we show that, as in humans, BALB/c IL-27 systemic levels are infection dependently upregulated and may favor parasite installation by controlling inflammation.

Dual Roles of IFN-γ and IL-4 in the Natural History of Murine Autoimmune Cholangitis: IL-30 and Implications for Precision Medicine

Primary biliary cirrhosis (PBC) is a progressive autoimmune liver disease with a long natural history. The pathogenesis of PBC is thought to be orchestrated by Th1 and/or Th17. In this study, we investigated the role of CD4⁺ helper T subsets and their cytokines on PBC using our previous established murine model of 2-OA-OVA immunization. We prepared adeno-associated virus (AAV)-IFN-γ and AAV-IL-4 and studied their individual influences on the natural history of autoimmune cholangitis in this model. Administration of IFN-γ significantly promotes recruitment and lymphocyte activation in the earliest phases of autoimmune cholangitis but subsequently leads to downregulation of chronic inflammation through induction of the immunosuppressive molecule IL-30. In contrast, the administration of IL-4 does not alter the initiation of autoimmune cholangitis, but does contribute to the exacerbation of chronic liver inflammation and fibrosis. Thus Th1 cells and IFN-γ are the dominant contributors in the initiation phase of this model but clearly may have different effects as the disease progress. In conclusion, better understanding of the mechanisms by which helper T cells function in the natural history of cholangitis is essential and illustrates that precision medicine may be needed for patients with PBC at various stages of their disease process.

Blockade of interleukin-27 signaling reduces GVHD in mice by augmenting Treg reconstitution and stabilizing Foxp3 expression

Reestablishment of competent regulatory pathways has emerged as a strategy to reduce the severity of graft-versus-host disease (GVHD), and recalibrate the effector and regulatory arms of the immune system. However, clinically feasible, cost-effective strategies that do not require extensive ex vivo cellular manipulation have remained elusive. In the current study, we demonstrate that inhibition of the interleukin-27p28 (IL-27p28) signaling pathway through antibody blockade or genetic ablation prevented lethal GVHD in multiple murine transplant models. Moreover, protection from GVHD was attributable to augmented global reconstitution of CD4⁺ natural regulatory T cells (nTregs), CD4⁺ induced Tregs (iTregs), and CD8⁺ iTregs, and was more potent than temporally concordant blockade of IL-6 signaling. Inhibition of IL-27p28 also enhanced the suppressive capacity of adoptively transferred CD4⁺ nTregs by increasing the stability of Foxp3 expression. Notably, blockade of IL-27p28 signaling reduced T-cell-derived-IL-10 production in conventional T cells; however, there was no corresponding effect in CD4⁺ or CD8⁺ Tregs, indicating that IL-27 inhibition had differential effects on IL-10 production and preserved a mechanistic pathway by which Tregs are known to suppress GVHD. Targeting of IL-27 therefore represents a novel strategy for the in vivo expansion of Tregs and subsequent prevention of GVHD without the requirement for ex vivo cellular manipulation, and provides additional support for the critical proinflammatory role that members of the IL-6 and IL-12 cytokine families play in GVHD biology.

Thymic DCs derived IL-27 regulates the final maturation of CD4(+) SP thymocytes

IL-27, as a pleiotropic cytokine, promotes the differentiation of naïve T cells to Th1, while suppressing Th2 and Th17 differentiation in the periphery. However, the role of IL-27 in the thymocyte development remains unknown. Here we showed that IL-27 was highly expressed in thymic plasmacytoid dendritic cells (pDCs) while its receptor expression was mainly detected in CD4⁺ single-positive (SP) thymocytes. Deletion of the p28 subunit in DCs resulted in a reduction of the most mature Qa-2⁺ subsets of CD4⁺ SP T cells. This defect was rescued by intrathymic administration of exogenous IL-27. In vitro differentiation assay further demonstrated that IL-27 alone was able to drive the maturation of the newly generated 6C10⁺CD69⁺CD4⁺ SP cells into Qa-2⁺ cells. Collectively, this study has revealed an important role of thymic DCs-derived IL-27 in the regulation of the phenotypic maturation of CD4⁺ SP thymocytes.

Interleukin-30 (IL27p28) alleviates experimental sepsis by modulating cytokine profile in NKT cells

BACKGROUND & AIMS

Sepsis is an acute systemic inflammatory response to infection associated with high patient mortality (28-40%). We hypothesized that interleukin (IL)-30, a novel cytokine protecting mice against liver injury resulting from inflammation, would generate a protective effect against systemic inflammation and sepsis-induced death.

METHODS

Sepsis was induced by lipopolysaccharide (LPS) or cecal ligation and puncture (CLP). The inhibitory effects of IL-30 on septic inflammation and associated therapeutic effects were determined in wild-type, IL30 (p28)(-/-), IL10(-/-), and CD1d(-/-) mice.

RESULTS

Mice treated with pIL30 gene therapy or recombinant IL-30 protein (rIL30) were protected from LPS-induced septic shock or CLP-induced polymicrobial sepsis and showed markedly less liver damage and lymphocyte apoptosis than control septic mice. The resulting reduction in mortality was mediated through attenuation of the systemic pro-inflammatory response and augmentation of bacterial clearance. Mice lacking IL-30 were more sensitive to LPS-induced sepsis. Natural killer-like T cells (NKT) produced much higher levels of IL-10 and lower levels of interferon-gamma and tumor necrosis factor-alpha in IL-30-treated septic mice than in control septic mice. Likewise, deficiency in IL-10 or NKT cells abolished the protective role of IL-30 against sepsis. Furthermore, IL-30 induced IL-10 production in purified and LPS-stimulated NKT cells. Blocking IL-6R or gp130 inhibited IL-30 mediated IL-10 production.

CONCLUSIONS

IL-30 is important in modulating production of NKT cytokines and subsequent NKT cell-mediated immune regulation of other cells. Therefore, IL-30 has a role in prevention and treatment of sepsis via modulation of cytokine production by NKT.