The IL-10/STAT3 axis: Contributions to immune tolerance by thymus and peripherally derived regulatory T-cells

T cell exhaustion in human cancers

T cell exhaustion refers to a progressive state in which T cells become functionally impaired due to sustained antigenic stimulation, which is characterized by increased expression of immune inhibitory receptors, but weakened effector functions, reduced self-renewal capacity, altered epigenetics, transcriptional programme and metabolism. T cell exhaustion is one of the major causes leading to immune escape of cancer, creating an environment that supports tumor development and metastatic spread. In addition, T cell exhaustion plays a pivotal role to the efficacy of current immunotherapies for cancer. This review aims to provide a comprehensive view of roles of T cell exhaustion in cancer development and progression. We summerized the regulatory mechanisms that involved in T cell exhaustion, including transcription factors, epigenetic and metabolic reprogramming events, and various microenvironmental factors such as cytokines, microorganisms, and tumor autocrine substances. The paper also discussed the challenges posed by T cell exhaustion to cancer immunotherapies, including immune checkpoint blockade (ICB) therapies and chimeric antigen receptor T cell (CAR-T) therapy, highlightsing the obstacles encountered in ICB therapies and CAR-T therapies due to T cell exhaustion. Finally, the article provides an overview of current therapeutic options aimed to reversing or alleviating T cell exhaustion in ICB and CAR-T therapies. These therapeutic approaches seek to overcome T cell exhaustion and enhance the effectiveness of immunotherapies in treating tumors.

Network meta-analysis of the molecular mechanisms and signaling pathways underlying alcohol-induced thymic atrophy

BACKGROUND

Thymic atrophy is characterized by loss of thymocytes, destruction of thymic architecture, and a subsequent decrease in naïve T cells with compromised immunity. Thymic atrophy occurs during aging. Environmental factors including alcohol misuse also induce thymic atrophy. Despite the link between alcohol misuse and thymic atrophy, the underlying mechanism is understudied. We aimed to identify molecules and signaling pathways that underly alcohol-induced thymic atrophy during aging.

METHODS

F344 rats were given 3-day binge-ethanol (4.8 g/kg/day; 52% w/v; i.g.) and the thymus was collected and weighed. Molecular mechanisms underlying ethanol-induced thymic atrophy were investigated by network meta-analysis using the QIAGEN Ingenuity Pathway Analysis (IPA). The molecules associated with ethanol were identified from the QIAGEN Knowledge Base (QKB) and those associated with thymic atrophy were identified from QKB and Mouse Genome Informatics (MGI). Aging-mediated Differential Expression Genes (DEGs) from mouse thymocytes were obtained from the Gene Expression Omnibus (GEO) database (GSE132136). The relationship between the molecules and associated signaling pathways were studied using IPA.

RESULTS

Binge-ethanol decreased thymic weight in F344 rats. Our meta-analysis using IPA identified molecules commonly shared by ethanol and thymic atrophy through which simulation with ethanol increased thymic atrophy. We then obtained aging-mediated DEGs from the atrophied thymocytes. We found that ethanol contributed to thymic atrophy through modulation of the aging-mediated DEGs. Our network meta-analysis suggests that ethanol may augment thymic atrophy through increased expression of cytokines (e.g., IL-6, IL-17A and IL-33) along with their regulators (e.g., STAT1 and STAT3).

CONCLUSIONS

Exposure to alcohol may augment thymic atrophy by altering the activity of key inflammatory mediators, such as STAT family members and inflammatory cytokines. These findings provide insights into the signaling pathways and upstream regulators that underly alcohol-induced thymic atrophy during aging, suggesting that alcohol consumption could prepone thymic atrophy.

Reprogramming of regulatory T cells in inflammatory tumor microenvironment: can it become immunotherapy turning point?

Overcoming the immunosuppressive tumor microenvironment and identifying widely used immunosuppressants with minimal side effects are two major challenges currently hampering cancer immunotherapy. Regulatory T cells (Tregs) are present in almost all cancer tissues and play an important role in preserving autoimmune tolerance and tissue homeostasis. The tumor inflammatory microenvironment causes the reprogramming of Tregs, resulting in the conversion of Tregs to immunosuppressive phenotypes. This process ultimately facilitates tumor immune escape or tumor progression. However, current systemic Treg depletion therapies may lead to severe autoimmune toxicity. Therefore, it is crucial to understand the mechanism of Treg reprogramming and develop immunotherapies that selectively target Tregs within tumors. This article provides a comprehensive review of the potential mechanisms involved in Treg cell reprogramming and explores the application of Treg cell immunotherapy. The interference with reprogramming pathways has shown promise in reducing the number of tumor-associated Tregs or impairing their function during immunotherapy, thereby improving anti-tumor immune responses. Furthermore, a deeper understanding of the mechanisms that drive Treg cell reprogramming could reveal new molecular targets for future treatments.

A first-in-human, open-label Phase 1b and a randomised, double-blind Phase 2a clinical trial in recent-onset type 1 diabetes with AG019 as monotherapy and in combination with teplizumab

AIMS/HYPOTHESIS

We hypothesised that islet beta cell antigen presentation in the gut along with a tolerising cytokine would lead to antigen-specific tolerance in type 1 diabetes. We evaluated this in a parallel open-label Phase 1b study using oral AG019, food-grade Lactococcus lactis bacteria genetically modified to express human proinsulin and human IL-10, as a monotherapy and in a parallel, randomised, double-blind Phase 2a study using AG019 in combination with teplizumab.

METHODS

Adults (18-42 years) and adolescents (12-17 years) with type 1 diabetes diagnosed within 150 days were enrolled, with documented evidence of at least one autoantibody and a stimulated peak C-peptide level >0.2 nmol/l. Participants were allocated to interventions using interactive response technology. We treated 42 people aged 12-42 years with recent-onset type 1 diabetes, 24 with Phase 1b monotherapy (open-label) and 18 with Phase 2a combination therapy. In the Phase 2a study, after treatment of the first two open-label participants, all people involved were blinded to group assignment, except for the Data Safety Monitoring Board members and the unblinded statistician. The primary endpoint was safety and tolerability based on the incidence of treatment-emergent adverse events, collected up to 6 months post treatment initiation. The secondary endpoints were pharmacokinetics, based on AG019 detection in blood and faeces, and pharmacodynamic activity. Metabolic and immune endpoints included stimulated C-peptide levels during a mixed meal tolerance test, HbA1c levels, insulin use, and antigen-specific CD4+ and CD8+ T cell responses using an activation-induced marker assay and pooled tetramers, respectively.

RESULTS

Data from 24 Phase 1b participants and 18 Phase 2a participants were analysed. No serious adverse events were reported and none of the participants discontinued AG019 due to treatment-emergent adverse events. No systemic exposure to AG019 bacteria, proinsulin or human IL-10 was demonstrated. In AG019 monotherapy-treated adults, metabolic variables were stabilised up to 6 months (C-peptide, insulin use) or 12 months (HbA1c) post treatment initiation. In participants treated with AG019/teplizumab combination therapy, all measured metabolic variables stabilised or improved up to 12 months and CD8+ T cells with a partially exhausted phenotype were significantly increased at 6 months. Circulating preproinsulin-specific CD4+ and CD8+ T cells were detected before and after treatment, with a reduction in the frequency of preproinsulin-specific CD8+ T cells after treatment with monotherapy or combination therapy.

CONCLUSIONS/INTERPRETATION

Oral delivery of AG019 was well tolerated and safe as monotherapy and in combination with teplizumab. AG019 was not shown to interfere with the safety profile of teplizumab and may have additional biological effects, including changes in preproinsulin-specific T cells. These preliminary data support continuing studies with this agent alone and in combination with teplizumab or other systemic immunotherapies in type 1 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03751007, EudraCT 2017-002871-24 FUNDING: This study was funded by Precigen ActoBio.

Spring Viremia of Carp Virus Infection Induces Carp IL-10 Expression, Both In Vitro and In Vivo

Interleukin-10 (IL-10) is a pleiotropic cytokine with both immune enhancement and immunosuppression activities, but the main role is immunosuppression and anti-inflammatory ability. In order to use the immunosuppressive function of IL-10, many viruses, such as SARS-CoV-2, hepatitis B virus and EB virus, can evade the host's immune surveillance and clearance by increasing the expression of host IL-10. However, it has not been reported whether the aquatic animal infection virus can upregulate the expression of host IL-10 and the mechanisms are still unknown. Spring viremia of carp (SVC) is a fatal viral disease for many fish species and is caused by spring viremia of carp virus (SVCV). This disease has caused significant economic losses in the aquaculture industry worldwide. In this study, the expression of carp IL-10 with or without infection of SVCV in epithelioma papulosum cyprinid (EPC) cells, carp head kidney (cHK) primary cells and common carp tissues were analyzed using RT-PCR and ELISA. The results show that SVCV infection induced carp IL-10 mRNA and protein expression, both in vitro and in vivo. However, the upregulation of carp IL-10 by SVCV was hindered by specific inhibitors of the JAK inhibitor (CP-690550), STAT3 inhibitor (STA-21), NF-κB inhibitor (BAY11-7082) and p38 MAPK (mitogen-activated protein kinase) inhibitor (SB202190), but not JNK inhibitor (SP600125). Furthermore, the results demonstrated that JAK1, JAK2, JAK3, TYK2 and STAT5 played important roles in carp IL-10 production induced by SVCV infection. Taken together, SVCV infection significantly induced carp IL-10 expression and the upregulation trigged in JAK-STAT, NF-κB and p38MAPK pathways. To our knowledge, this is the first time that a fish infection virus upregulated the host IL-10 expression through the JAK-STAT, NF-κB and p38MAPK pathways. Altogether, fish viruses may have a similar mechanism as human or other mammalian viruses to escape host immune surveillance and clearance.

CircGNB1 drives osteoarthritis pathogenesis by inducing oxidative stress in chondrocytes

BACKGROUND

Circular RNAs (circRNAs) have risen to prominence as important regulators of biological processes. This study investigated whether circGNB1 functions as a competitive endogenous RNA to regulate the pathological process of oxidative stress in age-related osteoarthritis (OA).

METHODS

The relationship between circGNB1 expression and oxidative stress/OA severity was determined in cartilages from OA patients at different ages. The biological roles of circGNB1 in oxidative stress and OA progression, and its downstream targets were determined using gain- and loss-of-function experiments in various biochemical assays in human chondrocytes (HCs). The in vivo effects of circGNB1 overexpression and knockdown were also determined using a destabilization of the medial meniscus (DMM) mouse model.

RESULTS

Increased circGNB1 expression was detected in HCs under oxidative and inflammatory stress and in the cartilage of older individuals. Mechanistically, circGNB1 sponged miR-152-3p and thus blocked its interaction with its downstream mRNA target, ring finger protein 219 (RNF219), which in turn stabilized caveolin-1 (CAV1) by preventing its ubiquitination at the K47 residue. CircGNB1 inhibited IL-10 signalling by antagonizing miR-152-3p-mediated RNF219 and CAV1 inhibition. Consequently, circGNB1 overexpression promoted OA progression by enhancing catabolic factor expression and oxidative stress and by suppressing anabolic genes in vitro and in vivo. Furthermore, circGNB1 knockdown alleviated the severity of OA, whereas circGNB1 overexpression had the opposite effect in a DMM mouse model of OA.

CONCLUSION

CircGNB1 regulated oxidative stress and OA progression via the miR-152-3p/RNF219/CAV1 axis. Modulating circGNB1 could be an effective strategy for treating OA.

Counteracting Immunosenescence-Which Therapeutic Strategies Are Promising?

Aging attenuates the overall responsiveness of the immune system to eradicate pathogens. The increased production of pro-inflammatory cytokines by innate immune cells under basal conditions, termed inflammaging, contributes to impaired innate immune responsiveness towards pathogen-mediated stimulation and limits antigen-presenting activity. Adaptive immune responses are attenuated as well due to lowered numbers of naïve lymphocytes and their impaired responsiveness towards antigen-specific stimulation. Additionally, the numbers of immunoregulatory cell types, comprising regulatory T cells and myeloid-derived suppressor cells, that inhibit the activity of innate and adaptive immune cells are elevated. This review aims to summarize our knowledge on the cellular and molecular causes of immunosenescence while also taking into account senescence effects that constitute immune evasion mechanisms in the case of chronic viral infections and cancer. For tumor therapy numerous nanoformulated drugs have been developed to overcome poor solubility of compounds and to enable cell-directed delivery in order to restore immune functions, e.g., by addressing dysregulated signaling pathways. Further, nanovaccines which efficiently address antigen-presenting cells to mount sustained anti-tumor immune responses have been clinically evaluated. Further, senolytics that selectively deplete senescent cells are being tested in a number of clinical trials. Here we discuss the potential use of such drugs to improve anti-aging therapy.

Endoplasmic reticulum stress impairs the immune regulation property of macrophages in asthmatic patients

The current study aims to characterize the counteraction of M2 cells in response to Endoplasmic reticulum (ER) stress. ER stress was detected in bronchoalveolar lavage fluids (BALF) Mϕs, which was at unresolved state in asthma patients. A positive correlation was detected between ER stress in Mϕs and lung functions/allergic mediators/Th2 cytokines in BALF or specific IgE in the serum. Levels of immune regulatory mediator in the BALF were negatively correlated to ER stress in BALF Mϕs. The ER stress state influenced the immune regulatory property of BALF Mϕ. Exposure to environmental pollutant, 3-metheyl-4-nitrophenol, exacerbated ER stress in Mϕ, which affected the Mϕ phenotyping. Exacerbation of ER stress suppressed the expression of IL-10 and programmed cell death protein-1 (PD-1) in Mϕs by increasing the expression of the ring finger protein 20 (Rnf20). Conditional inhibition of Rnf20 in Mϕs attenuated experimental airway allergy.

IL-10 Promotes CXCL13 Expression in Macrophages Following Foot-and-Mouth Disease Virus Infection

Foot-and-mouth disease (FMD) is one of the most contagious livestock diseases in the world, posing a constant global threat to the animal trade and national economies. The chemokine C-X-C motif chemokine ligand 13 (CXCL13), a biomarker for predicting disease progression in some diseases, was recently found to be increased in sera from mice infected with FMD virus (FMDV) and to be associated with the progression and severity of the disease. However, it has not yet been determined which cells are involved in producing CXCL13 and the signaling pathways controlling CXCL13 expression in these cells. In this study, the expression of CXCL13 was found in macrophages and T cells from mice infected with FMDV, and CXCL13 was produced in bone-marrow-derived macrophages (BMDMs) by activating the nuclear factor-kappaB (NF-κB) and JAK/STAT pathways following FMDV infection. Interestingly, CXCL13 concentration was decreased in sera from interleukin-10 knock out (IL-10-/-) mice or mice blocked IL-10/IL-10R signaling in vivo after FMDV infection. Furthermore, CXCL13 was also decreased in IL-10-/- BMDMs and BMDMs treated with anti-IL-10R antibody following FMDV infection in vitro. Lastly, it was demonstrated that IL-10 regulated CXCL13 expression via JAK/STAT rather than the NF-κB pathway. In conclusion, the study demonstrated for the first time that macrophages and T cells were the cellular sources of CXCL13 in mice infected with FMDV; CXCL13 was produced in BMDMs via NF-κB and JAK/STAT pathways; and IL-10 promoted CXCL13 expression in BMDMs via the JAK/STAT pathway.

Braun Lipoprotein Protects against Escherichia coli-Induced Inflammatory Responses and Lethality in Mice

Escherichia coli (E. coli), a Gram-negative bacterium, is an important pathogen that causes several mammalian diseases. The outer membrane components of E. coli, namely, lipopolysaccharide (LPS) and bacterial lipoprotein, can induce the host innate immune response through pattern recognition receptors (PRRs). However, the detailed roles of the E. coli Braun lipoprotein (BLP) in the regulation of host inflammatory response to E. coli infection remain unclear. In this study, we sought to determine the effects of BLP on E. coli-induced host inflammatory response and lethality using mouse models. Experiments using the E. coli DH5α strain (BLP-positive), E. coli JE5505 strain (BLP-negative), and E. coli JE5505 strain combined with BLP indicated that the presence of BLP could alleviate mortality and organ (liver and lung) damage and decrease proinflammatory cytokine (tumor necrosis factor alpha [TNF-α] and interleukin-1β [IL-1β]) and chemokine (regulated on activation normal T-cell expressed and secreted [RANTES]) production in mouse serum and organs. Conversely, E. coli JE5505, E. coli DH5α strain, and E. coli JE5505 combined with BLP treatment induce enhanced anti-inflammatory cytokine (interleukin 10 [IL-10]) production in mouse serum and organs. In addition, BLP could regulate the secretion of proinflammatory cytokines (TNF-α and IL-1β), chemokines (RANTES), and anti-inflammatory factors (IL-10) through mitogen-activated protein kinase (MAPK) and nuclear factor-kappaB (NF-κB) signaling pathways in macrophages. Altogether, our results demonstrate that the bacterial component BLP plays crucial and protective roles in E. coli-infected mice, which may influence the outcome of inflammation in host response to E. coli infection. IMPORTANCE In this study, we investigated the roles of bacterial outer membrane component BLP in regulating inflammatory responses and lethality in mice that were induced by a ubiquitous and serious pathogen, Escherichia coli. BLP could alleviate the mortality of mice and organ damage, as well as decrease proinflammatory cytokines and chemokine production and enhance anti-inflammatory cytokine production in mouse serum and organs. Overall, our results demonstrate that the bacterial component BLP plays crucial and protective roles in E. coli-infected mice through regulating the production of an inflammatory mediator, which may influence the outcome of inflammation in host response to E. coli infection. Our findings provide new information about the basic biology involved in immune responses to E. coli and host-bacterial interactions, which have the potential to translate into novel approaches for the diagnosis and treatment of E. coli-related medical conditions, such as bacteremia and sepsis.

MiRNA-374b-5p and miRNA-106a-5p are related to inflammatory bowel disease via regulating IL-10 and STAT3 signaling pathways

Background

Inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, is one of the most frequent gastrointestinal disorders worldwide. Although the actual etiology of IBD remains unclear, growing evidence suggests that CD4+ T cells-associated cytokines, including interferon (IFN)-γ, interleukin (IL)-10 and IL-17A, are crucial for the occurrence of IBD. It has been reported that there is a positive association between miRNAs and IBD development. In this study, we investigated the roles of hsa-miRNA-374b-5p(miRNA-374b-5p) and hsa-miRNA-106a-5p(miRNA-106a-5p) in regulating IBD development.

Methods

Serum was obtained from vein blood of IBD patients and healthy controls, qRT-PCR was performed to study the expression of miRNA-374b-5p and miRNA-106a-5p. Furthermore, we investigate the effects of overexpression or inhibition of miRNA-374b-5p on naïve CD4 + T cell subsets differentiation from vein blood of healthy controls by RT-qPCR, flow cytometry and western blot. And more the prediction and confirmation of the targeting genes of miRNA-374b-5p and miRNA-106a-5p were performed by bioinformatics softwares and dual-luciferase reporter assay.

Results

The results showed that miRNA-106a-5p and miRNA-374b-5p were significantly overexpressed in IBD patients. MiRNA-374b-5p could enhance Th1/Th17 cell differentiation and was related to IBD pathogenesis. MiRNA-374b-5p overexpression induced the mRNA expression of IL-17A and IFN-γ, and suppressed that of IL-10 in T cells. MiRNA-374b-5p inhibition decreased the mRNA expression of IL-17A and IFN-γ, while upregulated that of IL-10 in T cells. These qPCR data were further verified at protein level by western blotting and flow cytometry. In addition, dual-luciferase reporter (DLR) assay indicated that miRNA-374b-5p was directly targeted by IL-10, a key anti-inflammatory cytokine for preventing the occurrence of IBD. Meanwhile, STAT3 was identified as a target gene of miRNA-106a-5p by DLR assays. Further analysis revealed that miRNA-374b-5p regulated JAK1 and STAT3 pathways in CD4+ T cells via IL-10/STAT3 axis. MiRNA-374b-5p overexpression remarkably decreased the mRNA expression and phosphorylated (ser-727) protein levels of STAT3, while miRNA-374b-5p inhibition had the opposite effects.

Conclusion

MiRNA-374b-5p and miRNA-106a-5p may contribute to IBD development by regulating IL-10/STAT3 signal transduction.

The chemistry and efficacy benefits of polysaccharides from Atractylodes macrocephala Koidz

Atractylodes macrocephala Koidz (AM), traditional Chinese medicine (TCM) with many medicinal values, has a long usage history in China and other oriental countries. The phytochemical investigation revealed the presence of volatile oils, polysaccharides, lactones, flavonoids, and others. The polysaccharides from AM are important medicinal components, mainly composed of glucose (Glc), galactose (Gal), rhamnose (Rha), arabinose (Ara), mannose (Man), galacturonic acid (GalA) and xylose (Xyl). It also showed valuable bioactivities, such as immunomodulatory, antitumour, gastroprotective and intestinal health-promoting, hepatoprotective, hypoglycaemic as well as other activities. At the same time, based on its special structure and pharmacological activity, it can also be used as immune adjuvant, natural plant supplement and vaccine adjuvant. The aim of this review is to summarize and critically analyze up-to-data on the chemical compositions, biological activities and applications of polysaccharide from AM based on scientific literatures in recent years.

Combinations of anti-GITR antibody and CD28 superagonist induce permanent allograft acceptance by generating type 1 regulatory T cells

Type 1 regulatory T (Tr1) cells represent a subset of IL-10-producing CD4⁺Foxp3^- T cells and play key roles in promoting transplant tolerance. However, no effective pharmacological approaches have been able to induce Tr1 cells in vivo. We herein report the combined use of a CD28 superagonist (D665) and anti-glucocorticoid-induced tumor necrosis factor receptor-related protein monoclonal antibody (G3c) to induce Tr1 cells in vivo. Large amounts of IL-10/interferon-γ-co-producing CD4⁺Foxp3^- Tr1 cells were generated by D665-G3c sequential treatment in mice. Mechanistic studies suggested that D665-G3c induced Tr1 cells via transcription factors Prdm1 and Maf. G3c contributed to Tr1 cell generation via the activation of mitogen-activated protein kinase-signal transducer and activator of transcription 3 signaling. Tr1 cells suppressed dendritic cell maturation and T cell responses and mediated permanent allograft acceptance in fully major histocompatibility complex-mismatched mice in an IL-10-dependent manner. In vivo Tr1 cell induction is a promising strategy for achieving transplant tolerance.

MSC-ACE2 Ameliorates Streptococcus uberis-Induced Inflammatory Injury in Mammary Epithelial Cells by Upregulating the IL-10/STAT3/SOCS3 Pathway

In the dairy industry, Streptococcus uberis (S. uberis) is one of the most important pathogenic bacteria associated with mastitis in milk-producing cows, causing vast economic loss. To date, the only real effective method of treating and preventing streptococcal mastitis is antimicrobial therapy. In many inflammatory diseases, mesenchymal stem cells (MSCs) and angiotensin-converting enzyme 2 (ACE2) play an anti-inflammatory and anti-injurious role. Accordingly, we hypothesized that MSCs overexpressing ACE2 (MSC-ACE2) would ameliorate the inflammatory injury caused by S. uberis in mammary epithelial cells more efficiently than MSC alone. By activating the transcription 3/suppressor of cytokine signaling 3 (IL-10/STAT3/SOCS3) signaling pathway, MSC-ACE2 inhibited the NF-κB, MAPKs, apoptosis, and pyroptosis passways. Moreover, MSC-ACE2 overturned the downregulation of Occludin, Zonula occludens 1 (ZO-1), and Claudin-3 expression levels caused by S. uberis, suggesting that MSC-ACE2 promotes the repair of the blood-milk barrier. MSC-ACE2 demonstrated greater effectiveness than MSC alone, as expected. Based on these results, MSC-ACE2 effectively inhibits EpH4-Ev cell’s inflammatory responses induced by S. uberis, and would be an effective therapeutic tool for treating streptococcal mastitis.

Constant Activation of STAT3 Contributes to the Development of Adenomyosis in Females

Adenomyosis is a benign uterine disease that causes dysmenorrhea, heavy menstrual bleeding, and infertility; however, its pathophysiology remains unclear. Since signal transducer and activator of transcription 3 (STAT3) is crucial for endometrial regeneration, we hypothesized that STAT3 participates in adenomyosis pathophysiology. To investigate the influence of STAT3 on adenomyosis development, this study was performed using a novel mouse model of adenomyosis and human specimens of eutopic endometria and adenomyosis lesions. We established a novel mouse model of adenomyosis by puncturing entire mouse uterine layers with a thin needle. Mouse eutopic and ectopic endometria showed a positive immunoreactivity for phosphorylated STAT3 (pSTAT3), the active form of STAT3. Decreased numbers of adenomyotic lesions and reduced expression of Cxcl1, Icam1, and Spp1, which are associated with immune cell chemotaxis and tissue regeneration, were observed in uterine Stat3-deficient mice compared with the controls. In humans, pSTAT3 was intensely expressed at both the eutopic endometrium and the adenomyotic lesions regardless of the menstrual cycle phases. Conversely, it was limitedly expressed in the eutopic endometrium during the menstrual and proliferative phases in women without adenomyosis. Our findings indicate that continuous STAT3 activation promotes adenomyosis development. STAT3 inhibition can be a promising treatment strategy in patients with adenomyosis.

The GT1-TPS Structural Domain Protein From Haemonchus contortus Could Be Suppressive Antigen of Goat PBMCs

Trehalose phosphate synthase (TPS), a key enzyme in trehalose synthesis, is not present in mammals but critical to the viability of a wide range of lower organisms. However, almost nothing is known about the function of Hc-TPS (GT1-TPS structural domain protein from Haemonchus contortus). In this study, Hc-TPS gene was cloned and the recombinant protein (rHc-TPS) was expressed and purified. The quantitative real-time PCR (qPCR) results showed that Hc-TPS was transcribed at different stages of H. contortus, with higher levels of transcription at the molting and embryo stages. Immunofluorescence analysis showed that Hc-TPS was widely distributed in adults, but the expression was mainly localized on the mucosal surface of the intestine as well as in the embryos of female worms. The impacts of rHc-TPS on peripheral blood mononuclear cell (PBMC) proliferation, nitric oxide (NO) generation, transcriptional expression of cytokines, and related pathways were examined by co-incubating rHc-TPS with goat PBMCs. The results showed that rHc-TPS significantly inhibited PBMC proliferation and NO secretion in a dose-dependent manner. We also found that rHc-TPS activated the interleukin (IL)-10/signal transducer and activator of transcription 3/suppressor of cytokine signaling 3 (IL-10/STAT3/SOCS3) axis and significantly promoted SOCS3 expression, while inhibiting interferon-gamma (INF-γ), IL-4, IL-9, and IL-2 pathways. Our findings may contribute to understanding the immune evasion mechanism for the parasite during host-parasite interactions and also help to provide ideas for discovering new drug targets.

Regulatory T Cells in Autoimmune Vasculitis

Blood vessels are indispensable for host survival and are protected from inappropriate inflammation by immune privilege. This protection is lost in patients with autoimmune vasculitides, a heterogeneous group of diseases causing damage to arteries, arterioles, and capillaries. Vasculitis leads to vascular wall destruction and/or luminal occlusion, resulting in hemorrhage and tissue ischemia. Failure in the quantity and quality of immunosuppressive regulatory T cells (Treg) has been implicated in the breakdown of the vascular immune privilege. Emerging data suggest that Treg deficiencies are disease-specific, affecting distinct pathways in distinct vasculitides. Mechanistic studies have identified faulty CD8+ Tregs in Giant Cell Arteritis (GCA), a vasculitis of the aorta and the large aortic branch vessels. Specifically, aberrant signaling through the NOTCH4 receptor expressed on CD8+ Treg cells leads to rerouting of intracellular vesicle trafficking and failure in the release of immunosuppressive exosomes, ultimately boosting inflammatory attack to medium and large arteries. In Kawasaki’s disease, a medium vessel vasculitis targeting the coronary arteries, aberrant expression of miR-155 and dysregulated STAT5 signaling have been implicated in undermining CD4+ Treg function. Explorations of mechanisms leading to insufficient immunosuppression and uncontrolled vascular inflammation hold the promise to discover novel therapeutic interventions that could potentially restore the immune privilege of blood vessels and pave the way for urgently needed innovations in vasculitis management.

IL-6/STAT3/Foxo1 Axis as a Target of Lycopene Ameliorates Atrazine-Induced Thymic Mitophagy and Pyroptosis Cross-talk

The intensive adoption of atrazine (ATZ) has been a persistently widespread pollutant in daily life. However, ATZ is still used as an essential herbicide in numerous countries because its toxic...

In vitro characterization of Haemonchus contortus trehalose-6-phosphate phosphatase and its immunomodulatory effects on peripheral blood mononuclear cells (PBMCs)

Background

Trehalose-6-phosphate phosphatase (TPP6) is a key enzyme in the trehalose biosynthesis pathway. The accumulation of TPP6 inside the body is harmful to the pathogen, but almost nothing is currently known about the function of TPP6 from Haemonchus contortus (CRE-GOB-1).

Methods

The H. contortus CRE-GOB-1 (HcGOB) gene was cloned and recombinant protein of GOB (rHcGOB) was expressed; transcription of the HcGOB gene at different developmental stages of H. contortus was then studied. The spatial expression pattern of the HcGOB gene in adult female and male worms was determined by both quantitative real-time PCR (qPCR) and immunofluorescence. The binding of the rHcGOB protein to goat PBMCs was assessed by immunofluorescence assay. The immunomodulatory impacts of rHcGOB on cell proliferation, nitric oxide generation and cytokine secretion were assessed by co-culture of rHcGOB protein with goat PBMCs.

Results

The HcGOB protein was transcribed in eggs, infective third-stage larvae (iL3s) and adults of H. contortus, with the highest transcript levels found in the egg stage. The transcript levels were significantly elevated in iL3s after manual desheathing. HcGOB was widely distributed in adult worms where it was mainly localized in the gut and gonads. rHcGOB was observed to bind to PBMCs and also to be recognized by sera collected from a goat infected with H. contortus. rHcGOB significantly activated the interleukin-10/transforming growth factor β/signal transducer and activator of transcription 3 (IL-10/TGF-β/STAT3) pathway in PBMCs while suppressing the transcription and expression of IL-4 and IL-17.

Conclusions

These results suggest that the HcGOB gene plays an important role in the development, parasitism and reproduction of H. contortus. The rHcGOB protein affected the immunomodulatory function of PBMCs in the in vitro study, suggesting that this protein would be a promising vaccine target.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05115-4.

High PTX3 expression is associated with a poor prognosis in diffuse large B-cell lymphoma

Tumor‐associated macrophages (TAMs) are associated with a poor prognosis of diffuse large B‐cell lymphoma (DLBCL). As macrophages are heterogeneous, the immune polarization and their pathological role warrant further study. We characterized the microenvironment of DLBCL by immunohistochemistry in a training set of 132 cases, which included 10 Epstein–Barr virus‐encoded small RNA (EBER)‐positive and five high‐grade B‐cell lymphomas, with gene expression profiling in a representative subset of 37 cases. Diffuse large B‐cell lymphoma had a differential infiltration of TAMs. The high infiltration of CD68 (pan‐macrophages), CD16 (M1‐like), CD163, pentraxin 3 (PTX3), and interleukin (IL)‐10‐positive macrophages (M2c‐like) and low infiltration of FOXP3‐positive regulatory T lymphocytes (Tregs) correlated with poor survival. Activated B cell‐like DLBCL was associated with high CD16, CD163, PTX3, and IL‐10, and EBER‐positive DLBCL with high CD163 and PTX3. Programmed cell death‐ligand 1 positively correlated with CD16, CD163, IL‐10, and RGS1. In a multivariate analysis of overall survival, PTX3 and International Prognostic Index were identified as the most relevant variables. The gene expression analysis showed upregulation of genes involved in innate and adaptive immune responses and macrophage and Toll‐like receptor pathways in high PTX3 cases. The prognostic relevance of PTX3 was confirmed in a validation set of 159 cases. Finally, in a series from Europe and North America (GSE10846, R‐CHOP‐like treatment, n = 233) high gene expression of PTX3 correlated with poor survival, and moderately with CSF1R, CD16, MITF, CD163, MYC, and RGS1. Therefore, the high infiltration of M2c‐like immune regulatory macrophages and low infiltration of FOXP3‐positive Tregs is associated with a poor prognosis in DLBCL, for which PTX3 is a new prognostic biomarker.

SNP-mediated binding of TBX1 to the enhancer element of IL-10 reduces the risk of Behçet's disease

Aims: The genetic association between Behçet's disease susceptibility and IL-10 has been confirmed in multiple cohorts, but the underlying mechanism of this association remains unclear. Materials & methods: We combined public resources and laboratory experiments (electrophoretic mobility shift assays, chromatin immunoprecipitation, luciferase reporter gene and CRISPR/Cas9 genome editing) to analyze transcription factor binding and enhancer activity controlling IL-10 expression. Results & conclusion: The T allele of noncoding rs3024490 within super-enhancer elements is able to specifically bind TBX1 and, in turn, promotes the enhancer activity and increased expression of IL-10. However, a relative deficiency in TBX1 in Behçet's disease patients leads to the low expression of IL-10 and increased risk of developing Behçet's disease.

The Role of Non-Immune Cell-Derived Extracellular Vesicles in Allergy

Extracellular vesicles (EVs), and especially exosomes, have been shown to mediate information exchange between distant cells; this process directly affects the biological characteristics and functionality of the recipient cell. As such, EVs significantly contribute to the shaping of immune responses in both physiology and disease states. While vesicles secreted by immune cells are often implicated in the allergic process, growing evidence indicates that EVs from non-immune cells, produced in the stroma or epithelia of the organs directly affected by inflammation may also play a significant role. In this review, we provide an overview of the mechanisms of allergy to which those EVs contribute, with a particular focus on small EVs (sEVs). Finally, we also give a clinical perspective regarding the utilization of the EV-mediated communication route for the benefit of allergic patients.

STAT3 but Not STAT5 Contributes to the Protective Effect of Electroacupuncture Against Myocardial Ischemia/Reperfusion Injury in Mice

Electroacupuncture (EA) can help reduce infarct size and injury resulting from myocardial ischemia/reperfusion (I/R); however, the underlying molecular mechanism remains unknown. We previously reported that STAT5 plays a critical role in the cardioprotective effect of remote ischemic preconditioning (RIPC). Here, we assessed the effects of electroacupuncture pretreatment (EAP) on myocardial I/R injury in the presence and/or absence of Stat5 in mice and investigated whether EAP exerts its cardioprotective effects in a STAT5-dependent manner. Adult Stat5^fl/fl and Stat5-cKO mice were exposed to EAP at Neiguan (PC6) for 7 days before the induction of I/R injury by left anterior descending (LAD) coronary artery ligation. The myocardial infarct size (IS), area at risk, and apoptotic rate of cardiomyocytes were detected. RT-qPCR and western blotting were used to measure gene and protein expression, respectively, in homogenized heart tissues. RNA-seq was used to identify candidate genes and pathways. Our results showed that EAP decreased IS and the rate of cardiomyocyte apoptosis. We further found that STAT5 was activated by EAP in Stat5^fl/fl mice but not in Stat5-cKO mice, whereas the opposite was observed for STAT3. Following EAP, the levels of the antiapoptotic proteins Bcl-xL, Bcl-2, and p-AKT were increased in the presence of Stat5, while that of interleukin 10 (IL-10) was increased in both Stat5^fl/fl and Stat5-cKO. The gene expression profile in heart tissues was different between Stat5^fl/fl and the Stat5-cKO mice with EAP. Importantly, the top 30 DEGs under EAP in the Stat5-cKO mice were enriched in the IL-6/STAT3 signaling pathway. Our results revealed for the first time that the protective effect of EAP following myocardial I/R injury was attributable to, but not dependent on, STAT5. Additionally, we found that EAP could activate STAT3 signaling in the absence of the Stat5 gene, and could also activate antiapoptotic, survival, and anti-inflammatory signaling pathways.

Deficiency in the frequency and function of Tr1 cells in IgAV and the possible role of IL-27

Objective

Type 1 regulatory T (Tr1) cells are involved in the pathogenesis of numerous immune-mediated diseases. However, little is known about whether and how Tr1 cells affect the development of IgA vasculitis (IgAV). We aimed to investigate this question in IgAV patients.

Methods

. Tr1 cells in peripheral blood and kidney tissue of IgAV patients were analysed by multi-parametric flow cytometry and immunofluorescence techniques. An in vitro assay of suppression of T cell proliferation and cytokine release was performed to evaluate the function of Tr1 cells. Real-time PCR and cell stimulation in vitro were used to explore the roles of IL-27 and early growth response gene 2 (EGR2).

Results

The frequency of Tr1 cells was decreased in peripheral blood but increased in kidney tissue from IgAV patients. A defective suppressive function of Tr1 cells in IgAV was observed. The frequency of Tr1 cells and the cytokines secreted by them were up-regulated in the presence of recombinant IL-27 in vitro. Moreover, IL-27 also increased the expression of EGR2. Furthermore, lower frequency of Tr1 cells during remission had a higher recurrence rate.

Conclusion

Tr1 cells are involved in the pathogenesis of IgAV. The low IL-27 in IgAV is responsible for impaired frequency and function of Tr1 cells, and EGR2 may be the specific transcription factor involved in the progression. Tr1 may be a risk factor for IgAV recurrence.

The Yin and Yang of Type 1 Regulatory T Cells: From Discovery to Clinical Application

Regulatory T cells are essential players of peripheral tolerance and suppression of inflammatory immune responses. Type 1 regulatory T (Tr1) cells are FoxP3^- regulatory T cells induced in the periphery under tolerogenic conditions. Tr1 cells are identified as LAG3⁺CD49b⁺ mature CD4⁺ T cells that promote peripheral tolerance through secretion of IL-10 and TGF-β in addition to exerting perforin- and granzyme B-mediated cytotoxicity against myeloid cells. After the initial challenges of isolation were overcome by surface marker identification, ex vivo expansion of antigen-specific Tr1 cells in the presence of tolerogenic dendritic cells (DCs) and IL-10 paved the way for their use in clinical trials. With one Tr1-enriched cell therapy product already in a Phase I clinical trial in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT), Tr1 cell therapy demonstrates promising results so far in terms of efficacy and safety. In the current review, we identify developments in phenotypic and molecular characterization of Tr1 cells and discuss the potential of engineered Tr1-like cells for clinical applications of Tr1 cell therapies. More than 3 decades after their initial discovery, Tr1 cell therapy is now being used to prevent graft versus host disease (GvHD) in allo-HSCT and will be an alternative to immunosuppression to promote graft tolerance in solid organ transplantation in the near future.

The expression of STAT3 inhibited the NF-ΚB signalling pathway and reduced inflammatory responses in mice with viral myocarditis

BACKGROUND

The aim of this study was to investigate the mechanism of STAT3 in reducing the inflammatory responses in mice with viral myocarditis (VMC).

METHODS

Induce and generate viral myocarditis by using coxsackievirus B3 (CVB3) infected cardiomyocyte-specific STAT3 conditional knockout (STAT3cKO) mice and BALB/c mice. Use RT-PCR and western blot techniques to detect the expression of related cytokines in the uninfected wild-type mice group (Control group), myocarditis wild-type mice group (Model group) and STAT3cKO group, as well as the differentiation of spleen T cells in each group. Eukaryotic expression plasmid pcDNA3-STAT3 can reduce the expression of inflammatory factors the in vitro cultured cardiomyocytes of the STAT3cKO group.

RESULTS

RT-PCR showed that compared with the Control group, the expression levels of VMC-related genes (NF-κB, TNF‑α, IL-1β and IL-1) and anti-inflammation-related cytokines (IL-10 and TGF-β) in the Model group went up (*p < 0.05, **p < 0.01, ***p < 0.001); and also compared with the Control group, the rise in the expression levels of the above VMC-related genes in the STAT3cKO group was particularly significant (***p < 0.001, ****p < 0.0001) but there was no significant difference in the expression of IL-10 and TGF-β. After 4 weeks, a second RT-PCR showed that the expression of inflammation-related genes in the STAT3cKO group continued to be activated (***p < 0.001, ****p < 0.0001). Western blotting was performed to detect the expression of p65, a key protein of the NF-κB signalling pathway. The results showed that the p65 protein content was increased and the IL-10 protein content was decreased in the STAT3cKO group; the results of the T cell differentiation test showed that the T cell differentiation rate increased in the STAT3cKO group (**p < 0.01). Eukaryotic expression plasmid pcDNA3-STAT3 could reduce the expression of NF-κB, TNF-α, IL-1β and IL-17 (**p < 0.01).

CONCLUSION

The expression of STAT3 gene in VMC could to a certain extent inhibit the NF-κB signalling pathway and reduce the inflammatory responses of VMC.

Acteoside Presents Protective Effects on Cerebral Ischemia/reperfusion Injury Through Targeting CCL2, CXCL10, and ICAM1

The objective of this study is to investigate the roles of acteoside (ACT) in cells with oxygen-glucose deprivation and reoxygenation (OGD/R)-induced injury and the underlying mechanisms. The differentially expressed genes (DEGs) in rats with middle cerebral artery occlusion were identified using GSE61616 data set. Kyoto Encyclopedia of Genes and Genomes pathway enrichment with the DEGs and the prediction of ACT's targets were conducted using The Comparative Toxicogenomics Database. The OGD/R model was established with bEnd.3 cells. Following that, bEnd.3 cells were treated by distinct concentrations of ACT and IL-10. The proliferation and apoptosis of cells were analyzed by cell counting kit-8 and flow cytometry assays, respectively. Western blot was used to check involved proteins. Herein, we identified CCL2, CXCL10, and ICAM1 as the targets of ACT, which were upregulated in tissues of MACO rats and cells with OGD/R-induced injury. ACT promoted the proliferation but reduce the apoptosis of cells with OGD/R-induced injury. Moreover, these effects of ACT were enhanced by IL-10. After being treated with ACT, IL-10, or ACT together with IL-10, the levels of CCL2, CXCL10, and ICAM1 were all decreased, whereas p-Stat3 was raised in cells with OGD/R-induced injury, while Stat3 expression presented no significant difference among groups. ACT protected cells against OGD/R-induced injury through regulating the IL-10/Stat3 signaling, indicating that ACT might be an effective therapy drug to lower cerebral ischemia/reperfusion injury.

Identification of an immune classification for cervical cancer and integrative analysis of multiomics data

BACKGROUND

To understand the molecular mechanisms of the antitumour response, we analysed the immune landscape of cervical cancer to identify novel immune molecular classes.

METHODS

We established a stable immune molecular classification using a nonnegative matrix factorization algorithm and validated the correlation in two validation sets of 249 samples.

RESULTS

Approximately 78% of cervical cancers (CCs) (228/293) were identified to show significant enrichment in immune cells (e.g., CD8 T cells and macrophages), a type I IFN response, enhanced cytolytic activity and high PDCD1, and these CCs were referred to as the "immune class". We further identified two subtypes of the immune class: active immune and exhausted subtypes. Although the active immune subtype was characterized by enrichment of IFN signatures and better survival, the exhausted subtype expressed activated stroma, a wound healing signature, enhanced M2 macrophages and absence of CD8 T cells and the TGF-β response signature. Integrative analysis of multiomics data identified EGFR, JUN, MYC, FN1 and SERPINE1 as key modulators of the tumour immune microenvironment and potential targets for combination therapies which was validated in two validation sets.

CONCLUSIONS

Our study introduces a novel immune classification that might predict ideal candidates to receive immunotherapy or specific combination therapies.

Shikonin-mediated PD-L1 degradation suppresses immune evasion in pancreatic cancer by inhibiting NF-κB/STAT3 and NF-κB/CSN5 signaling pathways

BACKGROUND

Pancreatic cancer (PC) is a highly fatal malignancy with few effective therapies currently available. Recent studies have shown that PD-L1 inhibitors could be potential therapeutic targets for the treatment of PC. The present study aims to investigate the effect of Shikonin on immune evasion in PC with the involvement of the PD-L1 degradation.

METHODS

Initially, the expression patterns of PD-L1 and NF-κB in PC were predicted in-silico using the GEPIA database, and were subsequently validated using PC tissues. Thereafter, the correlation of NF-κB with STAT3, CSN5 and PD-L1 was examined. PC cells were treated with Shikonin, NF-κB inhibitor, STAT3 activator, and CSN5 overexpression plasmid to investigate effects on PD-L1 glycosylation and immune evasion in PC. Finally, in vivo tumor formation was induced in C57BL/6J mice, in order to verify the in vitro results.

RESULTS

PD-L1, NF-κB, NF-κB p65, STAT3, and CSN5 were highly expressed in PC samples, and NF-κB was positively correlated with STAT3/CSN5/PD-L1. Inhibition of NF-κB decreased PD-L1 glycosylation and increased PD-L1 degradation, whereas activated STAT3 and overexpressed CSN5 reversed these trends. Shikonin blocked immune evasion in PC, and lowered the expression of PD-L1, NF-κB, NF-κB p65, STAT3 and CSN5 in vivo and in vitro.

CONCLUSION

The findings indicated Shikonin inhibited immune evasion in PC by inhibiting PD-L1 glycosylation and activating the NF-κB/STAT3 and NF-κB/CSN5 signaling pathways. These effects of Shikonin on PC cells may bear important potential therapeutic implications for the treatment of PC.

IL-10-Producing ILCs: Molecular Mechanisms and Disease Relevance

Innate lymphoid cells (ILCs) are mainly composed of natural killer (NK) cells and helper-like lymphoid cells, which play a vital role in maintaining tissue homeostasis, enhancing adaptive immunity and regulating tissue inflammation. Alteration of the distribution and function of ILCs subgroups are closely related to the pathogenesis of inflammatory diseases and cancers. Interleukin-10 (IL-10) is a highly pleiotropic cytokine, and can be secreted by several cell types, among of which ILCs are recently verified to be a key source of IL-10. So far, the stable production of IL-10 can only be observed in certain NK subsets and ILC2s. Though the regulatory mechanisms for ILCs to produce IL-10 are pivotal for understanding ILCs and potential intervenes of diseases, which however is largely unknown yet. The published studies show that ILCs do not share exactly the same mechanisms for IL-10 production with helper T cells. In this review, the molecular mechanisms regulating IL-10 production in NK cells and ILC2s are discussed in details for the first time, and the role of IL-10-producing ILCs in diseases such as infections, allergies, and cancers are summarized.

YQWY Decoction Improves Myocardial Remodeling via Activating the IL-10/Stat3 Signaling Pathway

Heart failure (HF) has been known as a global health problem, and cardiac remodeling plays an essential role in the development of HF. We hypothesized that YQWY decoction might exert a cardioprotective effect against myocardium inflammation, fibrosis, and apoptosis via activating the interleukin-10 (IL-10)/Stat3 signaling pathway. To test this hypothesis, the HF model in rats was established by pressure overload through the minimally invasive transverse aortic constriction (MTAC). Echocardiography was performed to assess the left ventricular function of rats. Myocardial fibrosis in rats was observed by Masson and Picrosirius red staining, and the degree of myocardial apoptosis was detected via TUNEL staining. In addition, expression levels of IL-10, tumor necrosis factor-α (TNF-α), Stat3 (P-Stat3), P65 (P-P65), CD68, collagen I, TGF-β, CTGF, Bax, Bcl-2, cleaved caspase-3, and PARP in rat serum and myocardium samples were examined by ELISA, western blot, and immunohistochemistry, respectively. YQWY decoction treatment significantly improved left ventricular function in HF rats, especially in those of the high-dose group (LVEF%: 51.29 ± 5.876 vs. 66.02 ± 1.264, P < 0.01;, LVFS%: 27.75 ± 3.757 vs. 37.76 ± 1.137, P < 0.01). Furthermore, YQWY decoction markedly inhibited MTAC-induced myocardial fibrosis as evidenced by downregulated collagen I, TGF-β, and CTGF in myocardium and alleviated apoptosis (downregulated caspase-3 and PARP and increased Bcl-2/Bax ratio in cardiomyocytes). In addition, YQWY decoction decreased the level of the proinflammatory cytokine TNF-α in both circulating blood and myocardium and attenuated infiltration of inflammatory cells in heart tissue from HF rats. Most importantly, YQWY decoction suppressed MTAC-induced NF-κB activation and phosphorylated Stat3 by upregulating IL-10 in rat heart tissues. Our study showed that YQWY decoction could attenuate MTAC-induced myocardial inflammation, fibrosis, apoptosis, and reverse the impairment of cardiac function in rats by activating the IL-10/Stat3 signaling pathway and improving myocardium remodeling. Our findings suggested a therapeutic potential of YQWY decoction in HF.

Impaired autophagy increases susceptibility to endotoxin-induced chronic pancreatitis

Chronic pancreatitis (CP) is associated with elevated plasma levels of bacterial lipopolysaccharide (LPS) and we have demonstrated reduced acinar cell autophagy in human CP tissue. Therefore, we investigated the role of autophagy in experimental endotoxin-induced pancreatic injury and aimed to identify LPS in human CP tissue. Pancreatic Atg7-deficient mice were injected with a single sub-lethal dose of LPS. Expression of autophagy, apoptosis, necroptosis, and inflammatory markers was determined 3 and 24 h later utilizing immunoblotting and immunofluorescence. The presence of LPS in pancreatic tissue from mice and from patients and healthy controls was determined using immunohistochemistry, immunoblots, and chromogenic assay. Mice lacking pancreatic autophagy exhibited local signs of inflammation and were particularly sensitive to the toxic effect of LPS injection as compared to control mice. In response to LPS, Atg7^Δpan mice exhibited enhanced vacuolization of pancreatic acinar cells, increase in TLR4 expression coupled to enhanced expression of NF-κΒ, JNK, and pro-inflammatory cytokines by acinar cells and enhanced infiltration by myeloid cells (but not Atg7^F/F controls). Cell death was enhanced in Atg7^Δpan pancreata, but only necroptosis and trypsin activation was further amplified following LPS injection along with elevated pancreatic LPS. The presence of LPS was identified in the pancreata from all 14 CP patients examined but was absent in the pancreata from all 10 normal controls. Altogether, these results support a potential role for metabolic endotoxemia in the pathogenesis of CP. Moreover, the evidence also supports the notion that autophagy plays a major cytoprotective and anti-inflammatory role in the pancreas, and blunting metabolic endotoxemia-induced CP.

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.

IL-10-Dependent and -Independent Mechanisms Are Involved in the Cardiac Pathology Modulation Mediated by Fenofibrate in an Experimental Model of Chagas Heart Disease

IL-10 is an anti-inflammatory cytokine that plays a significant role in the modulation of the immune response in many pathological conditions, including infectious diseases. Infection with Trypanosoma cruzi (T. cruzi), the etiological agent of Chagas disease, results in an ongoing inflammatory response that may cause heart dysfunction, ultimately leading to heart failure. Given its infectious and inflammatory nature, in this work we analyzed whether the lack of IL-10 hinders the anti-inflammatory effects of fenofibrate, a PPARα ligand, in a murine model of Chagas heart disease (CHD) using IL-10 knockout (IL-10 KO) mice. Our results show fenofibrate was able to restore the abnormal cardiac function displayed by T. cruzi-infected mice lacking IL-10. Treatment with fenofibrate reduced creatine kinase (CK) levels in sera of IL-10 KO mice infected with T. cruzi. Moreover, although fenofibrate could not modulate the inflammatory infiltrates developing in the heart, it was able to reduce the increased collagen deposition in infected IL-10 KO mice. Regarding pro-inflammatory mediators, the most significant finding was the increase in serum IL-17. These were reduced in IL-10 KO mice upon fenofibrate treatment. In agreement with this, the expression of RORγt was reduced. Infection of IL-10 KO mice increased the expression of YmI, FIZZ and Mannose Receptor (tissue healing markers) that remained unchanged upon treatment with fenofibrate. In conclusion, our work emphasizes the role of anti-inflammatory mechanisms to ameliorate heart function in CHD and shows, for the first time, that fenofibrate attains this through IL-10-dependent and -independent mechanisms.

Differential roles of uterine epithelial and stromal STAT3 coordinate uterine receptivity and embryo attachment

Although it has been reported that uterine signal transducer and activator of transcription 3 (STAT3) is essential for embryo implantation, the exact roles of uterine epithelial and stromal STAT3 on embryo implantation have not been elucidated. To address this issue, we generated Stat3-floxed/Ltf-iCre (Stat3-eKO), Stat3-floxed/Amhr2-Cre (Stat3-sKO), and Stat3-floxed/Pgr-Cre (Stat3-uKO) mice to delete Stat3 in uterine epithelium, uterine stroma, and whole uterine layers, respectively. We found that both epithelial and stromal STAT3 have critical roles in embryo attachment because all the Stat3-eKO and Stat3-sKO female mice were infertile due to implantation failure without any embryo attachment sites. Stat3-eKO uteri showed indented structure of uterine lumen, indicating the role of epithelial STAT3 in slit-like lumen formation in the peri-implantation uterus. Stat3-sKO uteri exhibited hyper-estrogenic responses and persistent cell proliferation of the epithelium in the peri-implantation uterus, suggesting the role of stromal STAT3 in uterine receptivity. In addition, Stat3-uKO female mice possessed not only the characteristic of persistent epithelial proliferation but also that of indented structure of uterine lumen. These findings indicate that epithelial STAT3 controls the formation of slit-like structure in uterine lumen and stromal STAT3 suppresses epithelial estrogenic responses and cell proliferation. Thus, epithelial and stromal STAT3 cooperatively controls uterine receptivity and embryo attachment through their different pathways.

Role of Liver-Mediated Tolerance in Nanoparticle-Based Tumor Therapy

In the last decades, the use of nanocarriers for immunotherapeutic purposes has gained a lot of attention, especially in the field of tumor therapy. However, most types of nanocarriers accumulate strongly in the liver after systemic application. Due to the default tolerance-promoting role of liver non-parenchymal cells (NPCs), Kupffer cells (KCs), liver sinusoidal endothelial cells (LSECs), and hepatic stellate cells (HSCs), their potential role on the immunological outcome of systemic nano-vaccination approaches for therapy of tumors in the liver and in other organs needs to be considered. Concerning immunological functions, KCs have been the focus until now, but recent studies have elucidated an important role of LSECs and HSCs as well. Therefore, this review aims to summarize current knowledge on the employment of nanocarriers for immunotherapeutic therapy of liver diseases and the overall role of liver NPCs in the context of nano-vaccination approaches. With regard to the latter, we discuss strategies on how to address liver NPCs, aiming to exploit and modulate their immunological properties, and alternatively how to avoid unwanted engagement of nano-vaccines by liver NPCs for tumor therapy.

Anti-tumor effects and mechanisms of Astragalus membranaceus (AM) and its specific immunopotentiation: Status and prospect

With cancer deaths increasing, the initiation, pathophysiology and curative management of cancer is receiving increasing attention. Traditional therapies such as surgery and chemoradiotherapy are often accompanied by suppression of host immunity, which increase the risk of metastasis. Astragalus membranceus (AM) is commonly utilized as one herbal medicine of traditional Chinese medicines (TCMs) with a variety of biological activities. Studies have shown that the active ingredients of AM and AM-based TCMs, combined with chemotherapy, can enhance anti-tumor efficacy in cancer patients, in addition to reduce complications and avoid side effects induced by chemotherapy. By using various cancer models and cell lines, AM has been found to be capable of shrinking or stabilizing tumors by direct anti-proliferation or pro-apoptosis effect on tumor cells. Further, AM ameliorates immunosuppression by activating M1 macrophages and T cells tumor-kill function in tumor microenvironment (TME). AM is also found to improve systemic immunity which may help promoting efficacy of chemotherapy and preventing metastasis. Thereby this review contributes to an understanding of AM as an adjunctive therapy in the whole course of cancer treatment, at the same time providing useful information for development of more effective anti-tumor medication. The combination of AM and immune checkpoint therapies has a promising therapeutic prospect, and the observation of direct efficacy and mechanisms on tumor growth and metastasis of AM combined with chemotherapies or other therapies require more in vivo validations and further clinical investigation as well.

Differential regulation of JAK/STAT-signaling in patients with ulcerative colitis and Crohn’s disease

In 2018, the pan-Janus kinase (JAK) inhibitor tofacitinib was launched for the treatment of ulcerative colitis (UC). Although tofacitinib has proven efficacious in patients with active UC, it failed in patients with Crohn’s disease (CD). This finding strongly hints at a different contribution of JAK signaling in both entities. Here, we review the current knowledge on the interplay between the JAK/signal transducer and activator of transcription (STAT) pathway and inflammatory bowel diseases (IBD). In particular, we provide a detailed overview of the differences and similarities of JAK/STAT-signaling in UC and CD, highlight the impact of the JAK/STAT pathway in experimental colitis models and summarize the published evidence on JAK/STAT-signaling in immune cells of IBD as well as the genetic association between the JAK/STAT pathway and IBD. Finally, we describe novel treatment strategies targeting JAK/STAT inhibition in UC and CD and comment on the limitations and challenges of the new drug class.

Maternal High Linoleic Acid Alters Placental Fatty Acid Composition

Fetal development is modulated by maternal nutrition during pregnancy. The dietary intake of linoleic acid (LA), an essential dietary n-6 polyunsaturated fatty acid (PUFA), has increased. We previously published that increased LA consumption during pregnancy does not alter offspring or placental weight but fetal plasma fatty acid composition; the developing fetus obtains their required PUFA from the maternal circulation. However, it is unknown if increased maternal linoleic acid alters placental fatty acid storage, metabolism, transport, and general placental function. Female Wistar-Kyoto rats were fed either a low LA diet (LLA; 1.44% of energy from LA) or high LA diet (HLA; 6.21% of energy from LA) for 10 weeks before pregnancy and during gestation. Rats were sacrificed at embryonic day 20 (E20, term = 22 days) and placentae collected. The labyrinth of placentae from one male and one female fetus from each litter were analyzed. High maternal LA consumption increased placental total n-6 and LA concentrations, and decreased total n-3 PUFA, alpha-linolenic acid (ALA), and docosahexaenoic acid (DHA). Fatty acid desaturase 1 (Fads1), angiopoietin-like 4 (Angptl4), and diacylglycerol lipase beta (Daglb) mRNA were downregulated in placentae from offspring from HLA dams. Maternal high LA downregulated the fatty acid transport protein 4 (Fatp4) and glucose transporter 1 (Slc2a1) mRNA in placentae. IL-7 and IL-10 protein were decreased in placentae from offspring from HLA dams. In conclusion, a high maternal LA diet alters the placental fatty acid composition, inflammatory proteins, and expressions of nutrient transporters, which may program deleterious outcomes in offspring.

Exosomes carry IL-10 and antigen/MHC II complexes to induce antigen-specific oral tolerance

BACKGROUND

It is known that the immune tolerance can be naturally established in the intestine, while the mechanism by which the immune tolerance development in the intestine is not fully understood yet. Vasoactive intestinal peptides (VIP) has the immune regulatory functions. This study aims to investigate the role of VIP in the immune tolerance development in the intestine.

METHODS

Intestinal epithelial cell (IEC)-derived exosomes were prepared. The exosomes carried IL-10 and antigen/MHC II complexes. VIP-deficient (VIPd) mice and wild type mice were employed to test the role of VIP in the development of immune tolerance in the intestine.

RESULTS

VIPd mice failed to induce type 1 regulatory T cells (Tr1 cells) in the intestine and retarded the establishment of antigen (Ag)-specific immune tolerance. Exposure to VIP in the culture induced IL-10 expression in intestinal epithelial cells (IECs). Exosomes derived from ovalbumin (OVA, used as a specific Ag)/VIP-primed IECs carried IL-10 and OVA/MHC II complexes; these exosomes were designated IL10CARs (IL-10/chimeric antigen receptor-carrying exosomes). IL10CARs could recognize OVA-specific CD4⁺ T cells and converted OVA-specific CD4^± T cells to OVA-specific Tr1 cells. Administration of IL10CARs suppressed experimental food allergy.

CONCLUSIONS

The data show that IL10CARs are capable of suppressing experimental FA by inducing antigen-specific Tr1 cells, which has the translation potential for FA treatment.

Heme oxygenase-1 alleviates eosinophilic inflammation by inhibiting STAT3-SOCS3 signaling

Airway inflammation of eosinophilic asthma (EA) attributes to Th2 response, leaving the role of Th17 response unknown. Signal transducer and activator of transcription 3 (STAT3) induce both suppressors of cytokine signaling 3 (SOCS3) and retinoic acid receptor-related orphan nuclear receptor γ (RORγt) to initiate Th17 cell differentiation which is inhibited by SOCS3, a negative feedback regulator of STAT3. Heme oxygenase-1 (HO-1) is a stress-responsive, cytoprotective, and immunoregulatory molecular. Two other isoforms of the enzyme includes HO-2 and HO-3. Because HO-2 does not exhibit stress-related upregulation and distributes mainly in nervous system and HO-3 shows a low enzymatic activity, we tested a hypothesized anti-inflammatory role for HO-1 in EA by inhibiting STAT3-SOCS3 signaling. Animal model was established with Ovalbumin in wild type Balb/C mice. Hemin or SNPP was intraperitoneally (IP) injected ahead of the animal model to induce or inhibit HO-1 expression. Airway inflammation was evaluated by bronchoalveolar lavage, hematoxyline and eosin staining, enzyme-linked immunosorbent assay, and Western blot analysis. In vivo results showed that HO-1 induction inhibited phosphorylation of STAT3 and expression of SOCS3 and RORγt, decreased Th2 and Th17 immune responses, and alleviated airway inflammation. In vitro results revealed that HO-1 inhibited phosphorylation of STAT3 and expression of SOCS3 in naive CD4⁺ T cells. These findings identify HO-1 induction as a potential therapeutic strategy for EA treatment by reducing STAT3 phosphorylation, STAT3-SOCS3-mediated Th2/Th17 immune responses, and ultimate allergic airway inflammation.

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

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

Probiotic extracts ameliorate nasal allergy by inducing interleukin-35-producing dendritic cells in mice

BACKGROUND

The therapeutic efficacy of allergic rhinitis (AR) needs to be improved. Probiotics have immunoregulatory functions. In this study we evaluated the effects of protein extracts of probiotics in the amelioration of AR.

METHODS

Extracts of Bifidobacterium infantis (EBI) were prepared by lysing the live probiotics. AR mice were developed to be used to evaluate the therapeutic efficacy of EBI.

RESULTS

The results show that EBI induced interleukin (IL)-10-producing dendritic cells (DCs) via increasing IL-35 and signal transducer and activator of transcription 3 (STAT3) phosphorylation. IL-10-expressing DCs induced IL-10-producing B cells (B10 cells), with the latter showing immunosuppressive functions. After challenge with specific antigens, AR mice showed sneezing, nasal itch, and increases in serum-specific immunoglobulin E (IgE) and mouse mast cell protease-1; higher levels of T helper 2 (Th2) cytokines (IL-4, 67.17 ± 10.66; IL-5, 62.83 ± 9.70; IL-13, 51.00 ± 6.69, before treatment) in nasal mucosal protein extracts, which were significantly suppressed (IL-4, 27.00 ± 6.66; IL-5, 23.86 ± 4.53; IL-13, 25.67 ± 4.93, after treatment (p < 0.001) by administration with EBI nasal drops.

CONCLUSION

EBI can suppress AR via inducing B10 cells. Thus, after carrying out required preclinical experiments and tests, EBI has the translational potential to be used in the treatment of AR and other allergic diseases.

Ubiquitin E3 Ligase Pellino-1 Inhibits IL-10-mediated M2c Polarization of Macrophages, Thereby Suppressing Tumor Growth

Pellino-1 is a ubiquitin (Ub) E3 ligase that plays a role in M1, but not M2a polarization of macrophages. However, it is unknown whether Pellino-1 regulates IL-10-mediated M2c polarization of macrophages. Here, we found that Pellino-1 attenuated tumor growth by inhibiting M2c polarization of macrophages. Upon IL-10 stimulation, Pellino-1-deificient bone marrow-derived macrophages (BMDMs) showed higher expression of M2c markers, but not M2a, and M2b markers than wild-type (WT) BMDMs, indicating that Pellino-1 inhibits M2c polarization of macrophages. Pellino-1-deficient BMDMs exhibited a defect in mitochondria respiration, but enhancement of glycolysis during M2c polarization. During M2c polarization of macrophages, Pellino-1 increased STAT1 phosphorylation via K63-linked ubiquitination of IL-1 receptor associated kinase 1 (IRAK1). Furthermore, Lysm-CrePellino-1 ^fl/fl mice showed enhancement of tumor growth via regulating M2c polarization of tumor-associated macrophages. These results demonstrate that Pellino-1 inhibits IL-10-induced M2c macrophage polarization via K63-linked ubiquitination of IRAK1 and activation of STAT1, thereby inhibiting tumor growth in vivo.

Analysis of the role of IL-10 in the phagocytosis of mIgM+ B lymphocytes in flounder (Paralichthys olivaceus)

B cells have been found to have phagocytic activity in recent years, but the studies exploring the regulation mechanisms are still lacking to date. In the present study, the recombinant interleukin-10 (rIL-10) was obtained to study the function of IL-10 on phagocytosis of flounder (Paralichthys olivaceus) mIgM⁺ B lymphocytes. Flow cytometric analysis showed that IL-10 significantly enhanced the phagocytosis of Edwardsiella tarda but not Lactococcus lactis by mIgM⁺ B lymphocytes. Moreover, significantly higher intracellular ROS levels were detected in mIgM⁺ B lymphocytes following rIL-10 stimulation. The qRT-PCR analysis showed that rIL-10 could upregulate the expressions of IL-10Rb and Stat3 in mIgM⁺ B lymphocytes, suggesting that IL-10 might modulate the phagocytosis of mIgM⁺ B lymphocytes by activating IL-10R and Stat3. In addition, we also found that the enhancing effect of IL-10 on phagocytosis and intracellular ROS levels of mIgM⁺ B lymphocytes were suppressed by the administration of niclosamide. These results collectively demonstrated that IL-10 enhanced mIgM⁺ B lymphocyte-mediated phagocytosis of E. tarda and intracellular bactericidal ability, and IL-10R and Stat3 might play a curial role in the regulation of IL-10-stimulated phagocytosis, which would deepen our understanding of regulation mechanism of B cell phagocytosis.