Regulation of immune responses by interleukin-27

Interleukin-27 Promotes Divergent Effects on HIV-1 Infection in Peripheral Blood Mononuclear Cells through BST-2/Tetherin

Interleukin-27 (IL-27) is able to inhibit HIV-1 replication in peripheral blood mononuclear cells (PBMCs), macrophages, and dendritic cells. Here, we identify that IL-27 can produce opposing effects on HIV-1 replication in PBMCs and that the HIV-1 restriction factor BST-2/Tetherin is involved in both inhibitory and enhancing effects on HIV-1 infection induced by IL-27. IL-27 inhibited HIV-1 replication when added to cells 2 h after infection, promoting the prototypical BST-2/Tetherin-induced virion accumulation at the cell membrane of HIV-1-infected PBMCs. BST-2/Tetherin gene expression was significantly upregulated in the IL-27-treated PBMCs, with a simultaneous increase in the number of BST-2/Tetherin⁺ cells. The silencing of BST-2/Tetherin diminished the anti-HIV-1 effect of IL-27. In contrast, IL-27 increased HIV-1 production when added to infected cells 4 days after infection. This enhancing effect was prevented by BST-2/Tetherin gene knockdown, which also permitted IL-27 to function again as an HIV-1 inhibitory factor. These contrasting roles of IL-27 were associated with the dynamic of viral production, since the IL-27-mediated enhancement of virus replication was prevented by antiretroviral treatment of infected cells, as well as by keeping cells under agitation to avoid cell-to-cell contact. Likewise, inhibition of CD11a, an integrin associated with HIV-1 cell-to-cell transmission, abrogated the IL-27 enhancement of HIV-1 production. Our findings illustrate the complexity of the HIV-1-host interactions and may impact the potential therapeutic use of IL-27 and other soluble mediators that induce BST-2/Tetherin expression for HIV-1 infection. IMPORTANCE Here, we describe new findings related to the ability of the cytokine IL-27 to regulate the growth of HIV-1 in CD4⁺ T lymphocytes. IL-27 has long been considered a potent inhibitor of HIV-1 replication, a notion based on several reports showing that this cytokine controls HIV-1 infection in peripheral blood mononuclear cells (PBMCs), monocyte-derived macrophages, and dendritic cells. However, our present results are contrary to the current knowledge that IL-27 acts only as a powerful downregulator of HIV-1 replication. We observed that IL-27 can either prevent or enhance viral growth in PBMCs, an outcome dependent on when this cytokine is added to the infected cells. We detected that the increase of HIV-1 dissemination is due to enhanced cell-to-cell transmission with the involvement of the interferon-induced HIV-1 restriction factor BST-2/Tetherin and CD11a (LFA-1), an integrin that participates in formation of virological synapse.

Classification of tuberculosis-related programmed cell death-related patient subgroups and associated immune cell profiling

Background

Tuberculosis (TB) is the deadliest communicable disease in the world with the exception of the ongoing COVID-19 pandemic. Programmed cell death (PCD) patterns play key roles in the development and progression of many disease states such that they may offer value as effective biomarkers or therapeutic targets that can aid in identifying and treating TB patients.

Materials and methods

The Gene Expression Omnibus (GEO) was used to gather TB-related datasets after which immune cell profiles in these data were analyzed to examine the potential TB-related loss of immune homeostasis. Profiling of differentially expressed PCD-related genes was performed, after which candidate hub PCD-associated genes were selected via a machine learning approach. TB patients were then stratified into two subsets based on the expression of PCD-related genes via consensus clustering. The potential roles of these PCD-associated genes in other TB-related diseases were further examined.

Results

In total, 14 PCD-related differentially expressed genes (DEGs) were identified and highly expressed in TB patient samples and significantly correlated with the abundance of many immune cell types. Machine learning algorithms enabled the selection of seven hub PCD-related genes that were used to establish PCD-associated patient subgroups, followed by the validation of these subgroups in independent datasets. These findings, together with GSVA results, indicated that immune-related pathways were significantly enriched in TB patients exhibiting high levels of PCD-related gene expression, whereas metabolic pathways were significantly enriched in the other patient group. Single cell RNA-seq (scRNA-seq) further highlighted significant differences in the immune status of these different TB patient samples. Furthermore, we used CMap to predict five potential drugs for TB-related diseases.

Conclusion

These results highlight clear enrichment of PCD-related gene expression in TB patients and suggest that this PCD activity is closely associated with immune cell abundance. This thus indicates that PCD may play a role in TB progression through the induction or dysregulation of an immune response. These findings provide a foundation for further research aimed at clarifying the molecular drivers of TB, the selection of appropriate diagnostic biomarkers, and the design of novel therapeutic interventions aimed at treating this deadly infectious disease.

Interleukin-27 Ameliorates Atherosclerosis in ApoE-/- Mice through Regulatory T Cell Augmentation and Dendritic Cell Tolerance

Atherosclerosis, which is characterized by chronic inflammation in the arterial wall, is driven by immune cells and cytokines. Recent evidence indicated that interleukin (IL)-27 showed pleiotropic properties in immune diseases. However, precise mechanisms of IL-27, especially in atherosclerosis remains unknown. In our research, we examined the influence of the administration of IL-27 and an anti-IL-27p28 antibody (anti-IL-27p28-Ab) on both the initiation and the progression of atherosclerosis. In the groups (both the initiation and the progression) receiving recombinant IL-27 administration, the formation of atherosclerotic plaques was suspended, and the percentage of regulatory T cells (LAP⁺ or Foxp3⁺) in the spleen and peripheral blood was increased. Meanwhile, the number of T helper 1 (Th1) and T helper 17 (Th17) cells was decreased. In the peripheral blood plasma, TGF-β and IL-10 expression were increased, while the levels of IFN-γ and IL-17 were reduced. As for lesions, the mRNA expression of Foxp3, TGF-β, and IL-10 was increased, while that of IFN-γ and IL-17 was reduced. In the anti-IL-27p28 antibody groups, we obtained opposite results. We also observed that DCs treated with IL-27 display a tolerogenic phenotype and that IL-27–treated tolerogenic DCs (tDCs) are likely to play a protective role during atherosclerosis. Our study indicates that IL-27 or adoptive transfer of IL-27 loaded tDCs may be a new therapeutic approach in atherosclerosis.

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.

An Insight Into Systemic Immune Response in Leishmania donovani Mediated Atypical Cutaneous Leishmaniasis in the New Endemic State of Himachal Pradesh, India

Leishmaniasis continues to afflict known and newer endemic sites despite global efforts towards its control and elimination. In this regard, the emergence of newer endemic sites with unusual disease formats is recognized wherein Leishmania donovani complex classically known to cause visceral disease is demonstrated to cause cutaneous manifestation. In this context, atypical cutaneous leishmaniasis (CL) cases caused by L. donovani genetic variants from the newer endemic state of Himachal Pradesh (HP) in India are beginning to be understood in terms of parasite determinants. The atypical CL manifestation further needs to be explored to define host immune correlates with a possible role in driving the unusual disease progression. In the given study, we performed comprehensive systemic-immune profiling of the atypical CL patients from the study area in HP, India, in comparison with the classical visceral leishmaniasis (VL) patients from the northeast region of India. The systemic immune response was studied using ELISA-based assessment of Th1, Th2, Th17, Treg, and Th22 specific plasma cytokine expression pattern and parasite-specific total serum IgG/IgG subclasses. The specified immune correlates are known to exhibit heterogeneous association with the different infecting parasite species, infection load, and co-lateral host immunopathology in classical CL and VL. In the atypical CL patient group, altered expression of IL-10 emerged as the key finding that could potentially fine-tune the Th1/Th17/Th22 effector cytokine axis towards a localized cutaneous manifestation. A reduced expression of IL-10 along with a high IFN-γ/IL-10 ratio as a readout of effective parasite killing defined atypical cutaneous outcome. In contrast, high circulatory IL-10 levels and a depressed IFN-γ/IL-10 ratio were seen in classical VL patients in line with an ineffective parasite-killing cytokine response. Overall, the study highlights new knowledge on host immune correlates in terms of cytokine expression pattern and IgG subclasses that underline atypical disease manifestation such that L. donovani, a generally visceralizing parasite species cause skin localized cutaneous lesions.

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.

Decreased serum levels of IL-27and IL-35 in patients with Graves disease

Objective

Graves' disease (GD) is an autoimmune disease causing the overproduction of the thyroid hormone from thyroid gland. This disease is mainly the result of the production of antibodies against TSH receptors. Cytokines play an important role in orchestrating the pathophysiology in autoimmune thyroid disease. The regulatory role of IL-12 on TH1 cells has been proven. IL-27 and IL-35, members of IL-12 cytokine family, are two cytokines that have been newly discovered. IL-35 has been identified as a novel immunosuppressive and anti-inflammatory cytokine while IL-27 has both inflammatory and anti-inflammatory functions. The objective of the current study was to examine the changes in the serum level of the foregoing cytokines in GD patients in comparison to healthy controls.

Methods

In this study, serum levels of IL-27 and IL-35 were determined by an ELISA method; anti TPO and anti Tg were measured by an RIA method in 40 new cases of Graves's disease. The findings were compared with 40 healthy controls.

Results

The results showed a significant difference between IL-27 and IL-35 regarding their serum levels with P values of 0.0001 and 0.024, respectively; anti TPO and anti Tg levels of the cases were also significantly different from controls (p < 0.001).

Conclusion

The reduction in the serum levels of IL-27 and IL-35 in GD patients compared to normal subjects suggests the possible anti-inflammatory role of these cytokines in GD.

IL-27 Negatively Regulates Tip-DC Development during Infection

Tumor necrosis factor (TNF)/inducible nitric oxide synthase (iNOS)-producing dendritic cells (Tip-DCs) have profound impacts on host immune responses during infections. The mechanisms regulating Tip-DC development remain largely unknown. Here, using a mouse model of infection with African trypanosomes, we show that a deficiency in interleukin-27 receptor (IL-27R) signaling results in escalated intrahepatic accumulation of Ly6C-positive (Ly6C⁺) monocytes and their differentiation into Tip-DCs. Blocking Tip-DC development significantly ameliorates liver injury and increases the survival of infected IL-27R^−/− mice. Mechanistically, Ly6C⁺ monocyte differentiation into pathogenic Tip-DCs in infected IL-27R^−/− mice is driven by a CD4⁺ T cell-interferon gamma (IFN-γ) axis via cell-intrinsic IFN-γ signaling. In parallel, hyperactive IFN-γ signaling induces cell death of Ly6C-negative (Ly6C⁻) monocytes in a cell-intrinsic manner, which in turn aggravates the development of pathogenic Tip-DCs due to the loss of the negative regulation of Ly6C⁻ monocytes on Ly6C⁺ monocyte differentiation into Tip-DCs. Thus, IL-27 inhibits the dual-track exacerbation of Tip-DC development induced by a CD4⁺ T cell–IFN-γ axis. We conclude that IL-27 negatively regulates Tip-DC development by preventing the cell-intrinsic effects of IFN-γ and that the regulation involves CD4⁺ T cells and Ly6C⁻ monocytes. Targeting IL-27 signaling may manipulate Tip-DC development for therapeutic intervention.

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.

The IL-27 component EBI-3 and its receptor subunit IL-27Rα are essential for the cytoprotective action of humanin on male germ cells†

Humanin (HN) is a mitochondrial-derived peptide that protects many cells/tissues from damage. We previously demonstrated that HN reduces stress-induced male germ cell apoptosis in rodents. HN action in neuronal cells is mediated through its binding to a trimeric cell membrane receptor composed of glycoprotein 130 (gp130), IL-27 receptor subunit (IL-27R, also known as WSX-1/TCCR), and ciliary neurotrophic factor receptor subunit (CNTFR). The mechanisms of HN action in testis remain unclear. We demonstrated in ex-vivo seminiferous tubules culture that HN prevented heat-induced germ cell apoptosis was blocked by specific anti-IL-27R, anti-gp130, and anti-EBI-3, but not by anti-CNTFR antibodies significantly. The cytoprotective action of HN was studied by using groups of il-27r-/- or ebi-3-/- mice administered the following treatment: (1) vehicle; (2) a single intraperitoneal (IP) injection of HN peptide; (3) testicular hyperthermia; and (4) testicular hyperthermia plus HN. We demonstrated that HN inhibited heat-induced germ cell apoptosis in wildtype but not in il-27r-/- or ebi-3-/- mice. HN restored heat-suppressed STAT3 phosphorylation in wildtype but not il-27r-/- or ebi-3-/- mice. Dot blot analyses showed the direct interaction of HN with IL-27R or EBI-3 peptide. Immunofluorescence staining showed the co-localization of IL-27R with HN and gp130 in Leydig cells and germ cells. We conclude that the anti-apoptotic effects of HN in mouse testes are mediated through interaction with EBI-3, IL-27R, and activation of gp130, whereas the role of CNTFR needs further studies. This suggests a multicomponent tissue-specific receptor for HN in the testis and links HN action with the IL-12/IL-27 family of cytokines.

Cytokine saga in visceral leishmaniasis

In humans, infection with Leishmania manifests into a spectrum of diseases. The manifestation of the diseases depend on the resultant evasion of the parasite to immune responses namely by macrophages, which is an exclusive host of Leishmania. The B cells valiantly mount antibody responses, however, to no avail as the Leishmania parasites occupy the intracellular niches of the macrophages and subvert the immune response. Extensive studies have been documented on the role of cell-mediated immunity (CMI) in protection and counter survival strategies of the parasites leading to downregulation of CMI. The present review attempts to discuss the cytokines in progression or resolution of visceral form of leishmaniasis or kala-azar, predominantly affecting the Indian subcontinent. The components/cytokine(s) responsible for the regulation of the critical balance of T helper cells and their subsets have been discussed in the perspective. Therefore, any strategy involving the treatment of visceral leishmania (VL) needs to consider the balance and regulation of T cell function.

Conundrums in leishmaniasis

Parasites of the genus Leishmania cause the disease leishmaniasis. As the sandfly vector transfers the promastigotes into the skin of the human host, the infection is either cured or exacerbated. In the process, there emerge several unsolved paradoxes of leishmaniasis. Chronologically, as the infections starts in skin, the role of the salivary proteins in supporting the infection or the host response to these proteins influencing the induction of immunological memory becomes a conundrum. As the parasite invokes inflammation, the infiltrating neutrophils may act as "Trojan Horse" to transfer parasites to macrophages that, along with dendritic cells, carry the parasite to lymphoid organs to start visceralization. As the visceralized infection becomes chronic, the acutely enhanced monocytopoiesis takes a downturn while neutropenia and thrombocytopenia ensue with concomitant rise in splenic colony-forming-units. These responses are accompanied by splenic and hepatic granulomas, polyclonal activation of B cells and deviation of T cell responses. The granuloma formation is both a containment process and a form of immunopathogenesis. The heterogeneity in neutrophils and macrophages contribute to both cure and progression of the disease. The differentiation of T-helper subsets presents another paradox of visceral leishmaniasis, as the counteractive T cell subsets influence the curing or non-curing outcome. Once the parasites are killed by chemotherapy, in some patients the cured visceral disease recurs as a cutaneous manifestation post-kala azar dermal leishmaniasis (PKDL). As no experimental model exists, the natural history of PKDL remains almost a black box at the end of the visceral disease.

Cytokines and the immune response in obesity-related disorders

The increasing prevalence of obesity and the associated morbidity and mortality are important public health problems globally. There is an important relationship between an unhealthy lifestyle and increased serum inflammatory cytokines. Adipocytes secrete several pro-inflammatory cytokines involved in the recruitment and activation of macrophages resulting in chronic low-grade inflammation. Increased cytokines in obese individual are related to the progression of several disorders including cardiovascular disease, hypertension, and insulin resistance. In present review we have summarized the crucial roles of cytokines and their inflammatory functions in obesity-related immune disorders.

Host-pathogen interaction in the tissue environment during Plasmodium blood-stage infection

Human malarial infection occurs after an infectious Anopheles mosquito bites. Following the initial liver-stage infection, parasites transform into merozoites, infecting red blood cells (RBCs). Repeated RBC infection then occurs during the blood-stage infection, while patients experience various malarial symptoms. Protective immune responses are elicited by this systemic infection, but excessive responses are sometimes harmful for hosts. As parasites infect only RBCs and their immediate precursors during this stage, direct parasite-host interactions occur primarily in the environment surrounded by endothelial lining of blood vessels. The spleen is the major organ where the immune system encounters infected RBCs, causing immunological responses. Its tissue structure is markedly altered during malarial infection in mice and humans. Plasmodium falciparum parasites inside RBCs express proteins, such as PfEMP-1 and RIFIN, transported to the RBC surfaces in order to evade immunological attack by sequestering themselves in the peripheral vasculature avoiding spleen or by direct immune cell inhibition through inhibitory receptors. Host cell production of regulatory cytokines IL-10 and IL-27 limits excessive immune responses, avoiding tissue damage. The regulation of the protective and inhibitory immune responses through host-parasite interactions allows chronic Plasmodium infection. In this review, we discuss underlying interaction mechanisms relevant for developing effective strategies against malaria.

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.

Genetic architecture study of rheumatoid arthritis and juvenile idiopathic arthritis

BACKGROUND

Rheumatoid arthritis and juvenile idiopathic arthritis are two types of autoimmune diseases with inflammation at the joints, occurring to adults and children respectively. There are phenotypic overlaps between these two types of diseases, despite the age difference in patient groups.

METHODS

To systematically compare the genetic architecture of them, we conducted analyses at gene and pathway levels and constructed protein-protein-interaction network based on summary statistics of genome-wide association studies of these two diseases. We examined their difference and similarity at each level.

RESULTS

We observed extensive overlap in significant SNPs and genes at the human leukocyte antigen region. In addition, several SNPs in other regions of the human genome were also significantly associated with both diseases. We found significantly associated genes enriched in 32 pathways shared by both diseases. Excluding genes in the human leukocyte antigen region, significant enrichment is present for pathways like interleukin-27 pathway and NO2-dependent interleukin-12 pathway in natural killer cells.

DISCUSSION

The identification of commonly associated genes and pathways may help in finding population at risk for both diseases, as well as shed light on repositioning and designing drugs for both diseases.

Early transcriptome profile of goat peripheral blood mononuclear cells (PBMCs) infected with peste des petits ruminant's vaccine virus (Sungri/96) revealed induction of antiviral response in an interferon independent manner

Sungri/96 vaccine strain is considered the most potent vaccine providing long-term immunity against peste des petits ruminants (PPR) in India. Previous studies in our laboratory highlighted induction of robust antiviral response in an interferon independent manner at 48 h and 120 h post infection (p.i.). However, immune response at the earliest time point 6 h p.i. (time taken to complete one PPRV life cycle), in PBMCs infected with Sungri/96 vaccine virus has not been investigated. This study was taken up to understand the global gene expression profiling of goat PBMCs after Sungri/96 PPRV vaccine strain infection at 6 h post infection (p.i.). A total of 1926 differentially expressed genes (DEGs) were identified with 616 - upregulated and 1310 - downregulated. TLR7/TLR3, IRF7/IRF1, ISG20, IFIT1/IFIT2, IFITM3, IL27 and TREX1 were identified as key immune sensors and antiviral candidate genes. Interestingly, type I interferons (IFNα/β) were not differentially expressed at this time point as well. TREX1, an exonuclease which inhibits type I interferons at the early stage of virus infection was found to be highly upregulated. IL27, an important antiviral host immune factor was significantly upregulated. ISG20, an antiviral interferon induced gene with exonuclease activity specific to ssRNA viruses was highly expressed. Functional profiling of DEGs showed significant enrichment of immune system processes with 233 genes indicating initiation of immune defense response in host cells. Protein interaction network showed important innate immune molecules in the immune network with high connectivity. The study highlights important immune and antiviral genes at the earliest time point.

Mucosal T follicular helper cells in SIV-infected rhesus macaques: contributing role of IL-27

Mesenteric lymph nodes (MLNs), that drain the large and small intestine, are critical sites for the induction of oral tolerance. Although depletion of CD4 T cells in the intestinal lamina propria is a hallmark of HIV infection, CD4 T cell dynamics in MLNs is less known due to the lack of accessibility to these LNs. We demonstrate the early loss of memory CD4 T cells, including T follicular helper cells (Tfh) and a remodeling of MLN architecture in SIV-infected rhesus macaques (RMs). Along with the loss of Tfh cells, we observe the loss of memory B cells and of germinal center B cells. Tfh cells display a Th1 profile with increased levels of the transcription factors that negatively impact on Tfh differentiation and of Stat5 phosphorylation. MLNs of SIV-infected RMs display lower mRNA transcripts encoding for IL-12, IL-23, and IL-35, whereas those coding for IL-27 are not impaired in MLNs. In vitro, IL-27 negatively impacts on Tfh cells and recapitulates the profile observed in SIV-infected RMs. Therefore, early defects of memory CD4 T cells, as well of Tfh cells in MLNs, which play a central role in regulating the mucosal immune response, may have major implications for Aids.

IL-23 and IL-27 Levels in Serum are Associated with the Process and the Recovery of Guillain-Barré Syndrome

IL-23 and IL-27 are believed to be involved in the pathogenesis of Guillain-Barré syndrome (GBS). However, changes in these cytokines during the dynamic pathological and recovery processes of GBS are not well described. In the present study, plasma was collected from 83 patients with various stages of GBS, 70 patients with central nervous system demyelinating diseases,70 patients with other neurological diseases (OND) and 70 age- and sex-matched healthy volunteers. Serum levels of IL-23, IL-27, and Campylobacter jejuni (CJ) IgM were assessed using enzyme linked immunosorbent assay (ELISA). We found that serum IL-23 levels of patients during the acute phase of GBS were significantly higher followed by a decreasing trend during the recovery phase of the disease. Serum IL-27 levels significantly increased during the acute phase of GBS, and gradually increased during the recovery phase. Interestingly, both the severity and subtype of GBS were closely associated with the two cytokines. IL-23 levels were positively correlated with IL-27 levels, prognosis, and other clinical parameters. Our findings confirm that IL-23 may show pro-inflammatory effects, especially at the early stage of GBS. IL-27 appears to have a dual role in GBS, with initial pro-inflammatory effects, followed by anti-inflammatory properties during recovery.

Intervening in disease through genetically-modified bacteria

The comprehension of the molecular basis of different diseases is rapidly being dissected as a consequence of advancing technology. Consequently, proteins with potential therapeutic usefulness, including cytokines and signaling molecules have been identified in the last decades. However, their clinical use is hampered by disadvantageous functional and economic considerations. One of the most important of these considerations is targeted topical delivery and also the synthesis of such proteins, which for intravenous use requires rigorous purification whereas proteins often do not withstand digestive degradation and thus cannot be applied per os. Recently, the idea of using genetically modified bacteria has emerged as an attempt to evade these important barriers. Using such bacteria can deliver therapeutic proteins or other molecules at place of disease, especially when disease is at a mucosal surface. Further, whereas intravenously applied therapeutic proteins require expensive methodology in order to become endotoxin-free, this is not necessary for local application of therapeutic proteins in the intestine. In addition, once created further propagation of genetically modified bacteria is both cheap and requires relatively little in conditioning with respect to transport of the medication, making such organisms also suitable for combating disease in developing countries with poor infrastructure. Although first human trials with such bacteria were already performed more as a decade ago, the recent revolution in our understanding of the role of human gut microbiome in health and diseases has unleashed a revolution in this field resulting in a plethora of potential novel prophylactic and therapeutic intervention against disease onset and development employing such organisms. Today, the engineering of human microbiome for health benefits and related applications now chances many aspects of biology, nanotechnology and chemistry. Here, we review genetically modified bacteria methodology as possible carriers of drug delivering and provided the origin and inspirations for new drug delivery systems.

Immune Checkpoint Targets for Host-Directed Therapy to Prevent and Treat Leishmaniasis

Leishmaniasis encompasses a group of diseases caused by protozoan parasites belonging to the genus Leishmania. These diseases range from life threatening visceral forms to self-healing cutaneous lesions, and each disease manifestations can progress to complications involving dissemination of parasites to skin or mucosal tissue. A feature of leishmaniasis is the key role host immune responses play in disease outcome. T cells are critical for controlling parasite growth. However, they can also contribute to disease onset and progression. For example, potent regulatory T cell responses can develop that suppress antiparasitic immunity. Alternatively, hyperactivated CD4+ or CD8+ T cells can be generated that cause damage to host tissues. There is no licensed human vaccine and drug treatment options are often limited and problematic. Hence, there is an urgent need for new strategies to improve the efficacy of current vaccine candidates and/or enhance both antiparasitic drug effectiveness and subsequent immunity in treated individuals. Here, we describe our current understanding about host immune responses contributing to disease protection and progression in the various forms of leishmaniasis. We also discuss how this knowledge may be used to develop new strategies for host-directed immune therapy to prevent or treat leishmaniasis. Given the major advances made in immune therapy in the cancer and autoimmune fields in recent years, there are significant opportunities to ride on the back of these successes in the infectious disease domain. Conversely, the rapid progress in our understanding about host immune responses during leishmaniasis is also providing opportunities to develop novel immunotherapy strategies that could have broad applications in diseases characterized by inflammation or immune dysfunction.

Association of IL-27 rs153109 and rs17855750 Polymorphisms with Risk and Response to Therapy in Acute Lymphoblastic Leukemia

Interleukin (IL)-27 is a cytokine with important anti-cancer activity. This study has evaluated the effects of IL-27 rs153109 and rs17855750 single nucleotide polymorphisms (SNPs) on risk of acute lymphoblastic leukemia (ALL) development, as well as their impact on prognosis and patient survival. A total of 200 patients and 210 healthy subjects were genotyped by polymerase chain reaction-restriction fragment length polymorphism. We observed a higher frequency of rs153109 AG and rs17855750 TG genotypes and allele G in patients compared to controls (p < 0.001). Combined G variant genotypes (AG + GG and TG + GG) also conferred significantly greater risk of ALL. There was a significant correlation between the genotypes of both SNPs with event-free survival (EFS). Patients with GG genotypes of both SNPs and those of rs153109 AG and rs17855750 TG had a shorter EFS than patients with rs153109 AA and rs17855750 TT genotypes (p ≤ 0.035). Combined G variant genotypes for both SNPs showed poorer response to therapy in all patients (p < 0.027) as well as B-ALL (rs153109, p < 0.001) and T-ALL (rs153109, p = 0.048) patients. In multivariate analysis, rs153109 combined G variant genotype was associated with shorter EFS (relative risk = 9.7, p = 0.026). Among those who relapsed, 87.1% had the rs153109 AG genotype and 77.4% had the rs17855750 TG genotype (p < 0.01). Patients had higher IL-27 serum levels compared to controls, but this did not differ between genotypes. In conclusion, the association of IL-27 rs153109 and rs17855750 polymorphisms with risk of ALL development and their impact on EFS suggested an important role for this cytokine in biology and response to ALL therapy.

Interleukin-27 augments the inhibitory effects of sorafenib on bladder cancer cells

Both sorafenib and interleukin-27 (IL-27) are antineoplastic drugs. This study aimed to investigate the synergistic effect of these two drugs on bladder cancer cells. HTB-9 and T24 cells were stimulated with IL-27 (50 ng/mL), sorafenib (2 μM) or the synergistic action of these two drugs. The cells without treatment acted as control. Cell proliferation, apoptosis and invasion were measured by bromodeoxyuridine assay, flow cytometry and modified Boyden chamber, respectively. Simultaneously, both modified Boyden chamber and scratch assay were used to assess cell migration. Finally, the phosphorylation levels of key kinases in the Akt/mechanistic target of rapamycin (mTOR)/mitogen-activated protein kinase (MAPK) pathway, and expression levels of matrix metalloproteinase (MMP)-2 and MMP-9 were detected by western blot analysis. Stimulation with IL-27 or sorafenib repressed proliferation, migration and invasion but promoted apoptosis, and the effects were all enhanced by the combination of these two drugs in HTB-9 cells. The effect of the combined treatment on bladder cancer cells was verified in T24 cells. Additionally, the phosphorylation levels of AKT, mTOR and MAPK as well as the expression levels of MMP-2 and MMP-9 were all decreased by a single treatment of IL-27 or sorafenib, and further decreased by the combined treatment of these two drugs. The combination of IL-27 and sorafenib inhibited proliferation, migration and invasion and promoted apoptosis of bladder cancer cells compared with mono-drug treatment. Additionally, the AKT/mTOR/MAPK pathway might be implicated in the functional effects by down-regulations of MMP-2 and MMP-9.

Use of Wild Type or Recombinant Lactic Acid Bacteria as an Alternative Treatment for Gastrointestinal Inflammatory Diseases: A Focus on Inflammatory Bowel Diseases and Mucositis

The human gastrointestinal tract (GIT) is highly colonized by bacterial communities, which live in a symbiotic relationship with the host in normal conditions. It has been shown that a dysfunctional interaction between the intestinal microbiota and the host immune system, known as dysbiosis, is a very important factor responsible for the development of different inflammatory conditions of the GIT, such as the idiopathic inflammatory bowel diseases (IBD), a complex and multifactorial disorder of the GIT. Dysbiosis has also been implicated in the pathogenesis of other GIT inflammatory diseases such as mucositis usually caused as an adverse effect of chemotherapy. As both diseases have become a great clinical problem, many research groups have been focusing on developing new strategies for the treatment of IBD and mucositis. In this review, we show that lactic acid bacteria (LAB) have been capable in preventing and treating both disorders in animal models, suggesting they may be ready for clinical trials. In addition, we present the most current studies on the use of wild type or genetically engineered LAB strains designed to express anti-inflammatory proteins as a promising strategy in the treatment of IBD and mucositis.

Interleukin-35: a Potential Therapeutic Agent for Autoimmune Diseases

Autoimmune diseases contain a large number of pathologies characterized by various factors that contribute to a breakdown in self-tolerance. Cytokine-mediated immunity plays an essential role in the pathogenesis of varieties of autoimmune diseases. Recent studies reveal that interleukin-35 (IL-35), a newly identified cytokine of IL-12 family, is implicated in the pathogenesis of autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), etc. In this review, we will discuss the biological features of IL-35 and summarize recent advances in the role of IL-35 in the development and pathogenesis of autoimmune diseases; the discoveries gained from these findings might translate into future therapies for these diseases.

Human Immunodeficiency Virus Type-1 Myeloid Derived Suppressor Cells Inhibit Cytomegalovirus Inflammation through Interleukin-27 and B7-H4

HIV/CMV co-infected persons despite prolonged viral suppression often experience persistent immune activation, have an increased frequency of myeloid derived suppressor cells (MDSC) and are at increased risk for cardiovascular disease. We examined how HIV MDSC control CD4⁺ T cell IFNγ response to a CMVpp65 peptide pool (CMVpp65). We show that HIV/CMV co-infected persons with virologic suppression and recovered CD4⁺ T cells compared to HIV(−)/CMV(+) controls exhibit an increase in CD4⁺CX3CR1⁺IFNγ⁺ cells in response to CMVpp65; MDSC depletion further augmented CD4⁺CX3CR1⁺IFNγ⁺ cells and IFNγ production. IL-2 and IFNγ in response to CMVpp65 were enhanced with depletion of MDSC expanded in presence of HIV (HIV MDSC), but decreased with culture of HIV MDSC with autologous PBMCs. CMVpp65 specific CD4⁺CX3CR1⁺IFNγ⁺ cells were also decreased in presence of HIV MDSC. HIV MDSC overexpressed B7-H4 and silencing B7-H4 increased the production of IL-2 and IFNγ from autologous cells; a process mediated through increased phosphorylated (p)-Akt upon stimulation with CMVpp65. Additionally, IL-27 regulated the expression of B7-H4 on HIV MDSC, and controlled CMV-specific T cell activity by limiting CMVpp65-IFNγ production and expanding CD4⁺IL-10⁺ regulatory T cells. These findings provide new therapeutic targets to control the chronic immune activation and endothelial cell inflammation observed in HIV-infected persons.

IL-27: a potential biomarker for responders to glatiramer acetate therapy

Glatiramer acetate (GA) is an FDA-approved efficacious drug for the treatment of relapsing-remitting multiple sclerosis (RRMS). However, this treatment is not effective for all RRMS patients. Therefore, it is important to identify reliable biomarkers that can predict a beneficial clinical response to GA therapy. Since an increase in IL-27 has been demonstrated to suppress autoimmune and allergic diseases of inflammatory origin, we examined the effect of GA on the production of IL-27. We observed that IL-27 production in PBMCs cultured with GA was heterogeneous amongst MS patients and healthy donors (HD), and thus, defined these MS patients as either efficient, weak, or non-IL-27 producers. Interestingly, GA could induce the expression of the IL-27p28 subunit more efficiently than the IL-27 EBI3 subunit, and the production of IL-27 depended on MHC class II binding by GA. In addition, we found that GA could augment Toll-like receptor (TLR)-mediated IL-27 production. Importantly, serum production of IL-27 and IL-10 was significantly increased at 6months during GA therapy in clinical responders to GA, but not in GA non-responders. Altogether, our data suggest that GA-induced IL-27 may represent a therapeutic mechanism of GA-mediated immunomodulation and that GA-mediated IL-27 production in PBMCs is worth exploring as a biomarker to screen for GA responders prior to the initiation of GA treatment.

Interleukin-27-Producing CD4(+) T Cells Regulate Protective Immunity during Malaria Parasite Infection

Interleukin-27 (IL-27) is a heterodimeric regulatory cytokine of the IL-12 family, which is produced by macrophages, dendritic cells, and B cells upon stimulation through innate immune receptors. Here, we described regulatory CD4(+) T cells that produce IL-27 in response to T cell receptor stimulation during malaria infection, inhibiting IL-2 production and clonal expansion of other T cells in an IL-27-dependent manner. IL-27-producing CD4(+) T cells were Foxp3(-)CD11a(+)CD49d(+) malaria antigen-specific CD4(+) T cells and were distinct from interferon-γ (IFN-γ) producing Th1 or IL-10 producing Tr1 cells. In mice lacking IL-27 in T cells, IL-2 production was restored and clonal expansion and IFN-γ production by specific CD4(+) T cells were improved, culminating in reduced parasite burden. This study highlights a unique population of IL-27 producing regulatory CD4(+) T cells and their critical role in the regulation of the protective immune response against malaria parasites.

Modulation of IL-27 in adipocytes during inflammatory stress

OBJECTIVE

While it is well established that adipose tissue-derived inflammation plays an important role in the pathogenic mechanisms linking obesity with metabolic dysfunction, the inflammatory mediators involved have not been fully elucidated. Here, we explored IL-12 family cytokines with a focus on IL-27 during obesity-induced inflammation in mice and cultured adipocytes (ADs) following exposure to inflammatory stimuli.

METHODS

Relative mRNA abundance of IL-12 cytokines was assessed by reverse transcription polymerase chain reaction (RT-PCR) in genetically obese B6-ob/ob mice as well as C57BL/6J mice fed a high-fat diet and in ADs following exposure to inflammatory stimuli. Protein secretion of cytokines into culture media was assessed by ELISA, and the biological outcome of IL-27 stimulation was assessed by RT-PCR and immunoblotting.

RESULTS

Heterodimeric subunits constituting IL-27 were significantly induced in obese mice. While all IL-12 genes were markedly induced by inflammatory stress in cultured ADs, IL-27 protein was the only cytokine secreted into culture media in response to inflammatory stress. Cultured ADs also responded to IL-27 stimulation with divergent outcomes that were dependent on the inflammatory milieu of target cells.

CONCLUSIONS

These findings support the premise of autocrine/paracrine mechanisms involving IL-27 in ADs under conditions of inflammatory stress that may link obesity with inflammatory diseases.

Interleukin-27 enhances TNF-α-mediated activation of human coronary artery endothelial cells

Immune cells and inflammatory mediators play important roles in the development of atherosclerotic vascular inflammation. IL-27 is a member of the IL-6/IL-12 family that can promote Th1 responses and augment the release of inflammatory mediators from human mast cells and monocytes. However, the direct effect of IL-27 on human coronary artery endothelial cells was unclear. In this study, the effects of IL-27 and TNF-α on the cell surface expression of adhesion molecules, inflammatory cytokines, and chemokines were investigated. Results showed that IL-27 alone could significantly promote the release of chemokine CXCL10. However, IL-27 could further significantly enhance the TNF-α-mediated upregulation of adhesion molecules ICAM-1 and VCAM-1, inflammatory cytokine IL-6, as well as chemokines CCL5 and CXCL10 from human coronary artery endothelial cells. The release of IL-6, CCL5, and CXCL10 were significantly suppressed by specific signaling molecule inhibitors, implying that the induction of these mediators from the human coronary artery endothelial cells could be differentially regulated by the c-Jun N-terminal kinase, p38 mitogen-activated protein kinase, and nuclear factor-κB pathways. These results provided new insights into the effect of IL-27 on the TNF-α mediated activation of human coronary artery endothelial cells in atherosclerotic vascular inflammation.

IL-Y, a synthetic member of the IL-12 cytokine family, suppresses the development of type 1 diabetes in NOD mice

The IL-12 family of heterodimeric cytokines, consisting of IL-12, IL-23, IL-27, and IL-35, has important roles in regulating the immune response. IL-12 family members are comprised of a heterodimer consisting of α and β chains: IL-12 (p40 and p35), IL-23 (p40 and p19), IL-27 (Ebi3 and p28), and IL-35 (Ebi3 and p35). Given the combinatorial nature of the IL-12 family, we generated adenoviral vectors expressing two putative IL-12 family members not yet found naturally, termed IL-X (Ebi3 and p19) and IL-Y (p40 and p28), as single-chain molecules. Single chain IL-Y (scIL-Y), but not scIL-X, was able to stimulate significantly a unique cytokine/chemokine expression profile as well as activate STAT3 in mice, in part, through a pathway involving IL-27Rα in splenocytes. Adenoviral-mediated, intratumoral delivery of scIL-Y increased tumor growth in contrast to the anti-tumor effects of scIL-12 and scIL-23. Similarly, treatment of prediabetic NOD mice by intravenous injection of Ad.scIL-Y prevented the onset of hyperglycemia. Analysis of cells from Ad.scIL-Y-treated NOD mice demonstrated that scIL-Y reduced expression of inflammatory mediators such as IFN-γ. Our data demonstrate that a novel, synthetic member of the IL-12 family, termed IL-Y, confers unique immunosuppressive effects in two different disease models and thus could have therapeutic applications.

Interleukin-27 Protects Cardiomyocyte-Like H9c2 Cells against Metabolic Syndrome: Role of STAT3 Signaling

The present results demonstrated that high glucose (G), salt (S), and cholesterol C (either alone or in combination), as mimicking extracellular changes in metabolic syndrome, damage cardiomyocyte-like H9c2 cells and reduce their viability in a time-dependent manner. However, the effects were greatest when cells were exposed to all three agents (GSC). The mRNA of glycoprotein (gp) 130 and WSX-1, both components of the interleukin (IL)-27 receptor, were present in H9c2 cells. Although mRNA expression was not affected by exogenous treatment with IL-27, the expression of gp130 mRNA (but not that of WSX-1 mRNA) was attenuated by GSC. Treatment of IL-27 to H9c2 cells increased activation of signal transducer and activator of transcription 3 (STAT3) and protected cells from GSC-induced cytochrome c release and cell damage. The protective effects of IL-27 were abrogated by the STAT3 inhibitor, stattic. The results of the present study clearly demonstrate that the STAT3 pathway triggered by anti-inflammatory IL-27 plays a role in protecting cardiomyocytes against GSC-mediated damage.

IL-27 Signaling Is Crucial for Survival of Mice Infected with African Trypanosomes via Preventing Lethal Effects of CD4+ T Cells and IFN-γ

African trypanosomes are extracellular protozoan parasites causing a chronic debilitating disease associated with a persistent inflammatory response. Maintaining the balance of the inflammatory response via downregulation of activation of M1-type myeloid cells was previously shown to be crucial to allow prolonged survival. Here we demonstrate that infection with African trypanosomes of IL-27 receptor-deficient (IL-27R^-/-) mice results in severe liver immunopathology and dramatically reduced survival as compared to wild-type mice. This coincides with the development of an exacerbated Th1-mediated immune response with overactivation of CD4⁺ T cells and strongly enhanced production of inflammatory cytokines including IFN-γ. What is important is that IL-10 production was not impaired in infected IL-27R^-/- mice. Depletion of CD4⁺ T cells in infected IL-27R^-/- mice resulted in a dramatically reduced production of IFN-γ, preventing the early mortality of infected IL-27R^-/- mice. This was accompanied by a significantly reduced inflammatory response and a major amelioration of liver pathology. These results could be mimicked by treating IL-27R^-/- mice with a neutralizing anti-IFN-γ antibody. Thus, our data identify IL-27 signaling as a novel pathway to prevent early mortality via inhibiting hyperactivation of CD4⁺ Th1 cells and their excessive secretion of IFN-γ during infection with African trypanosomes. These data are the first to demonstrate the essential role of IL-27 signaling in regulating immune responses to extracellular protozoan infections.

Infection with extracellular protozoan parasites, African trypanosomes, is characterized by a persistent inflammatory immune response. It has been recently shown that maintaining the balance of the inflammatory responses via dampening M1-type myeloid cell activation is critical to guarantee control of the parasites and survival of the host. In this study, we demonstrated that IL-27 receptor-deficient (IL-27R^-/-) mice infected with African trypanosomes developed an excessive inflammatory response and severe liver immunopathology, resulting in dramatically reduced survival, as compared to infected wild-type mice. The early mortality of infected IL-27R^-/- mice was correlated with significantly elevated secretions of inflammatory cytokines, particularly IFN-γ, and enhanced activation of CD4⁺ Th1 cells. Importantly, IL-10 production was not impaired in infected IL-27R^-/- mice. Either depletion of CD4⁺ T cells, resulting in a dramatically reduced secretion of IFN-γ, or neutralization of IFN-γ, prevented the early mortality of infected IL-27R^-/- mice with a significantly reduced inflammatory response and a major amelioration of the liver pathology. Thus, our data identify IL-27 signaling as a novel pathway to prevent the early mortality via inhibiting hyperactivation of CD4⁺ Th1 cells and their excessive secretions of IFN-γ during experimental infection with extracellular protozoan parasites African trypanosomes.

Current Review of Genetically Modified Lactic Acid Bacteria for the Prevention and Treatment of Colitis Using Murine Models

Inflammatory Bowel Diseases (IBD) are disorders of the gastrointestinal tract characterized by recurrent inflammation that requires lifelong treatments. Probiotic microorganisms appear as an alternative for these patients; however, probiotic characteristics are strain dependent and each probiotic needs to be tested to understand the underlining mechanisms involved in their beneficial properties. Genetic modification of lactic acid bacteria (LAB) was also described as a tool for new IBD treatments. The first part of this review shows different genetically modified LAB (GM-LAB) described for IBD treatment since 2000. Then, the two principally studied strategies are discussed (i) GM-LAB producing antioxidant enzymes and (ii) GM-LAB producing the anti-inflammatory cytokine IL-10. Different delivery systems, including protein delivery and DNA delivery, will also be discussed. Studies show the efficacy of GM-LAB (using different expression systems) for the prevention and treatment of IBD, highlighting the importance of the bacterial strain selection (with anti-inflammatory innate properties) as a promising alternative. These microorganisms could be used in the near future for the development of therapeutic products with anti-inflammatory properties that can improve the quality of life of IBD patients.

Decreased IL-27 Negatively Correlated with Th17 Cells in Non-Small-Cell Lung Cancer Patients

The presence of Th17 cells and IL-27 is observed in a variety of inflammatory associated cancers. However, there are some data on the role of Th17 cells and IL-27 in the regulation of immune reactions in non-small-cell lung cancer (NSCLC). The aim of this study is to assess the variation of Th17 cells and IL-27 in the peripheral blood (PB) of patients with NSCLC. The proportion of Th17 cells in peripheral blood mononuclear cells (PBMCs) was evaluated by flow cytometry. The serum concentrations of IL-27 and IL-17 were measured by enzyme-linked immunosorbent assay (ELISA). The mRNA expression of RORγt and IL-27 in the peripheral blood was examined by real-time quantitative polymerase chain reaction (QPCR). Expression of IL-27 was lower in NSCLC patients compared with normal controls. The frequency of Th17 cells was increased in NSCLC patients, accompanied by the upregulation of IL-17 and RORγt. IL-27 negatively correlated with the number of Th17 cells and the RORγt mRNA. Our results indicate that IL-27 might inhibit Th17 differentiation in NSCLC patients and better understanding of the regulatory effects of IL-27 on Th17 cells may shed light on potential new targets in cancer prevention and therapy.

Interleukin-27, a novel cytokine induced by ischemia-reperfusion injury in rat hearts, mediates cardioprotective effects via the gp130/STAT3 pathway

Patients with coronary artery disease show high serum levels of interleukin (IL)-27, a novel member of the IL-6 family. However, the function of IL-27 in hearts suffering ischemia/reperfusion (IR) injury is unclear. Here, we showed increased expression of mRNA for the IL-27 subunits, EBI3 and p28, in rat hearts after 40 min of coronary ligation and release for 7 days. This increase was associated with a peak in the release of the cardiac enzyme, creatine kinase-MB, on day 2 post-release. Moreover, levels of IL-27 receptor subunit gp130 mRNA, but not those of subunit WSX-1 mRNA, decreased in post-ischemic hearts. These results suggest that increased IL-27 production may compensate for receptor downregulation during myocardial recovery. Lactate dehydrogenase release and crystal violet staining revealed that IL-27 or IL-6 significantly attenuated severe hypoxia (SH, 2 % O2)-induced cell damage in H9c2 cardiomyoblasts and primary rat neonatal cardiomyocytes. Incubating cardiomyocytes with IL-27 or IL-6 resulted in time-dependent activation of signal transducers and activators of transcription 3 (STAT3). Interestingly, IL-27-induced STAT3 activation was attenuated by pre-treatment with a gp130-neutralizing antibody. Blocking gp130 also reduced the cytoprotective effects of IL-27 or IL-6. Moreover, IL-27-mediated protection against SH was blocked by stattic, a small-molecule inhibitor of STAT3. IL-27 markedly improved post-ischemic recovery and reduced tissue damage in isolated perfused hearts when administered 5 min before reperfusion. These results indicate that IL-27 protects the myocardium against IR injury and facilitates the recovery of damaged cardiomyocytes via the gp130/STAT3 pathway.

[Potential relationship and clinical significance of miRNAs and Th17 related cytokines in patients with multiple myeloma]

目的

探讨miRNA和Th17相关细胞因子在多发性骨髓瘤(MM)患者发病中的作用机制。

方法

收集27例MM患者骨髓标本，以8名健康人为正常对照，应用荧光实时定量PCR(qRT-PCR)法检测其miR-15a/16、-34a、-194-2-192簇、-181a/b的表达情况，采用ELISA法检测患者血清Th17相关细胞因子IL-17、IL-21、IL-22、IL-23、IL-27的表达水平。分析miRNA与Th17相关细胞因子表达的相关性。

结果

与对照组比较，MM患者组miR-15a/16、-34a、-194-2-192簇表达水平降低，而miR-181a/b表达水平升高，差异均有统计学意义（P值均<0.05）；MM患者血清IL-17、IL-21、IL-27的表达水平升高，IL-22表达水平降低，差异均有统计学意义（P值均<0.05）；IL-23表达水平与对照组相比差异无统计学意义（P>0.05)。ISS分期Ⅲ期患者的miR-181a/b和IL-17、IL-21、IL-23、IL-27表达水平高于Ⅰ期患者，而miR-15a/16、-34a、-194和IL-22的表达水平则低于后者，差异均有统计学意义（P值均< 0.05）。miR-34a与IL-21，miR-181a与IL-23，miR-192与IL-21、IL-27，miR-194与IL-27的表达水平均呈正相关，而miR-192与IL-21呈负相关（P值均<0.05）。

结论

miRNA和Th17相关细胞因子在MM患者中均存在异常表达，其表达水平与MM患者的ISS分期有关，同时两者之间也存在密切的联系，提示失调的miRNA可能影响Th17细胞的分化进而参与MM的发生、发展。

Transcriptional analysis identifies key genes involved in metabolism, fibrosis/tissue repair and the immune response against Fasciola hepatica in sheep liver

BACKGROUND

Although fascioliasis has been relatively well studied, little is known about the molecular basis of this disease. This is particularly relevant, considering the very different response that sheep have to Fasciola hepatica relative to cattle. The acute phase of this disease is severe in sheep, whereas chronic fascioliasis is more common in cattle.

METHODS

To begin to explore the host-response to Fasciola in sheep and improve the understanding of the host-pathogen interactions during the parasite's migration through liver parenchyma to the bile duct, we used RNA sequencing (RNA-seq) to investigate livers from sheep infected for eight weeks compared with those from uninfected controls.

RESULTS

This study identified 572 and 42 genes that were up- and down-regulated, respectively, in infected livers relative to uninfected controls. Our molecular findings provide significant new insights into the mechanisms linked to metabolism, fibrosis and tissue-repair in sheep, and highlight the relative importance of specific components of immune response pathways, which appear to be driven toward a suppression of inflammation.

CONCLUSIONS

This study is, to our knowledge, the first detailed investigation of the transcriptomic responses in the liver tissue of any host to F. hepatica infection. It defines the involvement of specific genes associated with the host's metabolism, immune response and tissue repair/regeneration, and highlights an apparent overlapping function of many genes involved in these processes.

IL-27 alleviates the bleomycin-induced pulmonary fibrosis by regulating the Th17 cell differentiation

Background

Interleukin-27 (IL-27) is a multifunctional cytokine with both pro-inflammatory and immunoregulatory functions. At present, the role of IL-27 in pulmonary fibrosis remains unknown.

Methods

In this study, we observed the expression of IL-27/IL-27R in a mouse model of bleomycin (BLM)-induced pulmonary fibrosis. We verified the role of IL-27 using hematoxylin and eosin as well as Masson’s staining methods and measuring the content of hydroxyproline as well as collagen I and III. We assessed the differentiation of T lymphocytes in the spleen and measured the concentration of cytokines in bronchoalveolar lavage fluid (BALF) and the expression level of relevant proteins in the JAK/STAT and TGF-ß/Smad signaling pathways in lung tissue.

Results

Increased IL-27 expression in BLM-induced pulmonary fibrosis was noted. IL-27 treatment may alleviate pulmonary fibrosis and increase the survival of mice. IL-27 inhibited the development of CD4⁺ IL-17⁺, CD4⁺ IL-4⁺ T, and CD4⁺ Foxp3⁺ cells and the secretion of IL-17, IL-4, IL-6, and TGF-ß. IL-27 induced the production of CD4⁺ IL-10⁺ and CD4⁺ INF-γ⁺ T cells. IL-27 decreased the levels of phosphorylated STAT1, STAT3, STAT5, Smad1, and Smad3 but increased the level of SOCS3.

Conclusions

This study demonstrates that IL-27 potentially attenuates BLM-induced pulmonary fibrosis by regulating Th17 differentiation and cytokine secretion.

IL-35: a potential therapeutic target for controlling hepatitis B virus infection

Interleukin (IL)-35, a recently identified cytokine of the IL-12 family, is a potent immunosuppressive cytokine secreted by regulatory T (Treg) cells and the newly reported regulatory B (Breg) cells. IL-35 functions as a crucial immunosuppressive factor in immune-mediated diseases, and the predominant mechanism of suppression is its ability to suppress T cell proliferation and effector functions. The pathogenic processes of the non-cytopathic hepatitis B virus (HBV) infection-related liver diseases are immune-mediated, including liver damage and viral control. It has been found that IL-35 is detectable in peripheral CD4(+) T cells in chronic HBV-infected patients, whereas it is undetectable in healthy individuals. There is growing evidence that cytokine-mediated immune responses play a pivotal role in determining the clinical outcome during HBV infection. It is particularly important to investigate the effects of IL-35 in the immunopathogenesis of chronic HBV infection. In this study, the recent understanding of this issue is discussed.

IL-27 enhances Leishmania amazonensis infection via ds-RNA dependent kinase (PKR) and IL-10 signaling

The protozoan parasite Leishmania infects and replicates in macrophages, causing a spectrum of diseases in the human host, varying from cutaneous to visceral clinical forms. It is known that cytokines modulate the immunological response against Leishmania and are relevant for infection resolution. Here, we report that Interleukin (IL)-27 increases Leishmania amazonensis replication in human and murine macrophages and that the blockage of the IL-10 receptor on the surface of infected cells abolished the IL-27-mediated enhancement of Leishmania growth. IL-27 induced the activation/phosphorylation of protein kinase R (PKR) in macrophages, and PKR blockage or PKR gene deletion abrogated the enhancement of the parasite growth driven by IL-27, as well as the L. amazonensis-induced macrophage production of IL-27. We also observed that L. amazonensis-induced expression of IL-27 depends on type I interferon signaling and the engagement of Toll-like receptor 2. Treatment of Leishmania-infected mice with IL-27 increased lesion size and parasite loads in the footpad and lymph nodes of infected animals, indicating that this cytokine exerts a local and a systemic effect on parasite growth and propagation. In conclusion, we show that IL-27 is a L. amazonensis-enhancing factor and that the PKR/IFN1 axis and IL-10 are critical mediators of this IL-27 induced effect.

IL-27 affects helper T cell responses via regulation of PGE2 production by macrophages

IL-27 is a heterodimeric cytokine that regulates both innate and adaptive immunity. The immunosuppressive effect of IL-27 largely depends on induction of IL-10-producing Tr1 cells. To date, however, effects of IL-27 on regulation of immune responses via mediators other than cytokines remain poorly understood. To address this issue, we examined immunoregulatory effects of conditional medium of bone marrow-derived macrophages (BMDMs) from WSX-1 (IL-27Rα)-deficient mice and found enhanced IFN-γ and IL-17A secretion by CD4(+) T cells as compared with that of control BMDMs. We then found that PGE2 production and COX-2 expression by BMDMs from WSX-1-deficient mice was increased compared to control macrophages in response to LPS. The enhanced production of IFN-γ and IL-17A was abolished by EP2 and EP4 antagonists, demonstrating PGE2 was responsible for enhanced cytokine production. Murine WSX-1-expressing Raw264.7 cells (mWSX-1-Raw264.7) showed phosphorylation of both STAT1 and STAT3 in response to IL-27 and produced less amounts of PGE2 and COX-2 compared to parental RAW264.7 cells. STAT1 knockdown in parental RAW264.7 cells and STAT1-deficiency in BMDMs showed higher COX-2 expression than their respective control cells. Collectively, our result indicated that IL-27/WSX-1 regulated PGE2 secretion via STAT1-COX-2 pathway in macrophages and affected helper T cell response in a PGE2-mediated fashion.

Potential relationship and clinical significance of miRNAs and Th17 cytokines in patients with multiple myeloma

We evaluated the potential relationship between miRNAs and Th17 cytokines in multiple myeloma (MM) patients. Twenty-seven newly diagnosed myeloma patients and eight normal donors were studied. We determined that the relative expression levels of miR-15a/16, miR-34a, miR-194 in MM patients were significantly lower than those in the healthy controls with exception for miR-181a/b, which showed significantly higher in MM patients (P<0.05). In contrast, the levels of IL-17, IL-21 and IL-27 were up-regulated in MM patients compared to healthy controls while IL-22 was down-regulated (P<0.05). The expression patterns of them were differentially present in various groups according to the International Staging System (ISS) criteria. Up-regulated IL-17, IL-21 and IL-27 may potentially down-regulate the expression of several miRNAs in MM patients. Establishment of the relationship may be useful for understanding the pathogenesis of MM and for clinical diagnosis of the disease.

Timed action of IL-27 protects from immunopathology while preserving defense in influenza

Infection with influenza virus can result in massive pulmonary infiltration and potentially fatal immunopathology. Understanding the endogenous mechanisms that control immunopathology could provide a key to novel adjunct therapies for this disease. Here we show that the cytokine IL-27 plays a crucial role in protection from exaggerated inflammation during influenza virus infection. Using Il-27ra^−/− mice, IL-27 was found to limit immunopathology, neutrophil accumulation, and dampened T_H1 or T_H17 responses via IL-10–dependent and -independent pathways. Accordingly, the absence of IL-27 signals resulted in a more severe disease course and in diminished survival without impacting viral loads. Consistent with the delayed expression of endogenous Il-27p28 during influenza, systemic treatment with recombinant IL-27 starting at the peak of virus load resulted in a major amelioration of lung pathology, strongly reduced leukocyte infiltration and improved survival without affecting viral clearance. In contrast, early application of IL-27 impaired virus clearance and worsened disease. These findings demonstrate the importance of IL-27 for the physiological control of immunopathology and the potential value of well-timed IL-27 application to treat life-threatening inflammation during lung infection.

Annual epidemics of influenza result in 3 to 5 million cases of severe illness and approximately 300,000 deaths around the world. Although most patients infected with normal circulating influenza A viruses recover from the illness, complications arise during infections with highly pathogenic strains of the virus, resulting in increased mortality associated with severe immunopathology and acute respiratory distress. Previous studies suggested a major contribution of the vigorous immune response to lung damage. How the immune system constrains the negative impact of inflammation might therefore be of significant importance for future therapies. Our study in a mouse model of influenza shows that the cytokine IL-27 plays a crucial role in survival by protecting against lung damage. Its actions include regulation of innate (neutrophil influx) and adaptive (inflammatory cytokine production of T cells) arms of immunity during the acute respiratory infection. The data also suggest a therapeutic potential of IL-27, as mice treated with recombinant cytokine at later stages of infection exhibited decreased immunopathology and showed improved survival. The findings uncover an important role of IL-27 in limiting the collateral damages of anti-viral immunity and provide initial evidence that these mechanisms might be exploited for the management of severe immunopathology after infection.