Homology of cytokine synthesis inhibitory factor (IL-10) to the Epstein-Barr virus gene BCRFI

Effects of interleukin-10 treated macrophages on bone marrow mesenchymal stem cells via signal transducer and activator of transcription 3 pathway

BACKGROUND

Alveolar bone defects caused by inflammation are an urgent issue in oral implant surgery that must be solved. Regulating the various phenotypes of macrophages to enhance the inflammatory environment can significantly affect the progression of diseases and tissue engineering repair process.

AIM

To assess the influence of interleukin-10 (IL-10) on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) following their interaction with macrophages in an inflammatory environment.

METHODS

IL-10 modulates the differentiation of peritoneal macrophages in Wistar rats in an inflammatory environment. In this study, we investigated its impact on the proliferation, migration, and osteogenesis of BMSCs. The expression levels of signal transducer and activator of transcription 3 (STAT3) and its activated form, phosphorylated-STAT3, were examined in IL-10-stimulated macrophages. Subsequently, a specific STAT3 signaling inhibitor was used to impede STAT3 signal activation to further investigate the role of STAT3 signaling.

RESULTS

IL-10-stimulated macrophages underwent polarization to the M2 type through substitution, and these M2 macrophages actively facilitated the osteogenic differentiation of BMSCs. Mechanistically, STAT3 signaling plays a crucial role in the process by which IL-10 influences macrophages. Specifically, IL-10 stimulated the activation of the STAT3 signaling pathway and reduced the macrophage inflammatory response, as evidenced by its diminished impact on the osteogenic differentiation of BMSCs.

CONCLUSION

Stimulating macrophages with IL-10 proved effective in improving the inflammatory environment and promoting the osteogenic differentiation of BMSCs. The IL-10/STAT3 signaling pathway has emerged as a key regulator in the macrophage-mediated control of BMSCs’ osteogenic differentiation.

Pharmacogenomic and epigenomic approaches to untangle the enigma of IL-10 blockade in oncology

The host immune system status remains an unresolved mystery among several malignancies. An immune-compromised state or smart immune-surveillance tactics orchestrated by cancer cells are the primary cause of cancer invasion and metastasis. Taking a closer look at the tumour-immune microenvironment, a complex network and crosstalk between infiltrating immune cells and cancer cells mediated by cytokines, chemokines, exosomal mediators and shed ligands are present. Cytokines such as interleukins can influence all components of the tumour microenvironment (TME), consequently promoting or suppressing tumour invasion based on their secreting source. Interleukin-10 (IL-10) is an interlocked cytokine that has been associated with several types of malignancies and proved to have paradoxical effects. IL-10 has multiple functions on cellular and non-cellular components within the TME. In this review, the authors shed the light on the regulatory role of IL-10 in the TME of several malignant contexts. Moreover, detailed epigenomic and pharmacogenomic approaches for the regulation of IL-10 were presented and discussed.

Regulatory ILC2-Role of IL-10 Producing ILC2 in Asthma

Over the past two decades, a growing body of evidence observations have shown group two innate lymphoid cells (ILC2) to be critical drivers of Type 2 (T2) inflammatory responses associated with allergic inflammatory conditions such as asthma. ILC2 releases copious amounts of pro-inflammatory T2 cytokines-interleukin (IL)-4, IL-5, IL-9, and IL-13. This review provides a comprehensive overview of the newly discovered regulatory subtype of ILC2 described in murine and human mucosal tissue and blood. These KLRG1+ILC2 have the capacity to produce the anti-inflammatory cytokine IL-10. Papers compiled in this review were based on queries of PubMed and Google Scholar for articles published from 2000 to 2023 using keywords "IL-10" and "ILC2". Studies with topical relevance to IL-10 production by ILC2 were included. ILC2 responds to microenvironmental cues, including retinoic acid (RA), IL-2, IL-4, IL-10, and IL-33, as well as neuropeptide mediators such as neuromedin-U (NMU), prompting a shift towards IL-10 and away from T2 cytokine production. In contrast, TGF-β attenuates IL-10 production by ILC2. Immune regulation provided by IL-10+ILC2s holds potential significance for the management of T2 inflammatory conditions. The observation of context-specific cues that alter the phenotype of ILC warrants examining characteristics of ILC subsets to determine the extent of plasticity or whether the current classification of ILCs requires refinement.

A meta-analysis of associations of IL-10 gene polymorphisms with acute leukemia susceptibility

BACKGROUND

Recently, increasing evidence has demonstrated that IL-10 single nucleotide polymorphisms (SNPs) are associated with the risk of acute leukemia (AL), but the findings of different articles remain controversial. Thus, we performed a meta-analysis to further investigate the exact roles of IL-10 SNPs in AL susceptibility.

METHODS

Six common Chinese and English databases were utilized to retrieve eligible studies. The strength of the association was assessed by calculating odds ratios and 95 % confidence intervals. All analyses were carried out using Review Manager (version 5.3) and STATA (version 15.1). The registered number of this research is CRD42022373362.

RESULTS

A total of 6391 participants were enrolled in this research. The results showed that the AG genotype of rs1800896 increased AL risk in the heterozygous codominant model (AG vs. AA, OR = 1.41, 95 % CI = 1.04-1.92, P = 0.03) and overdominant model (AG vs. AA + GG, OR = 1.32, 95 % CI = 1.04-1.70, P = 0.03). In the subgroup analysis, associations between the G allele, GG genotype, AG genotype, AG + GG genotype of rs1800896 and increased AL risk were also observed in the mixed population based on allelic, homozygote codominant, heterozygous codominant, dominant, and overdominant models. Furthermore, an association between the AC genotype of rs1800872 and increased AL risk was observed in the Caucasian population in the overdominant model. However, the rs1800871, rs3024489 and rs3024493 polymorphisms did not affect AL risk.

CONCLUSION

IL-10 rs1800896 and rs1800872 affected the susceptibility of AL and therefore may be biomarkers for early screening and risk prediction of AL.

Virologs, viral mimicry, and virocell metabolism: the expanding scale of cellular functions encoded in the complex genomes of giant viruses

The phylum Nucleocytoviricota includes the largest and most complex viruses known. These "giant viruses" have a long evolutionary history that dates back to the early diversification of eukaryotes, and over time they have evolved elaborate strategies for manipulating the physiology of their hosts during infection. One of the most captivating of these mechanisms involves the use of genes acquired from the host-referred to here as viral homologs or "virologs"-as a means of promoting viral propagation. The best-known examples of these are involved in mimicry, in which viral machinery "imitates" immunomodulatory elements in the vertebrate defense system. But recent findings have highlighted a vast and rapidly expanding array of other virologs that include many genes not typically found in viruses, such as those involved in translation, central carbon metabolism, cytoskeletal structure, nutrient transport, vesicular trafficking, and light harvesting. Unraveling the roles of virologs during infection as well as the evolutionary pathways through which complex functional repertoires are acquired by viruses are important frontiers at the forefront of giant virus research.

Molecular Characterization and Expression Analysis of IL-10 and IL-6 in Channel Catfish (Ictalurus punctatus)

IL-10 and IL-6 play important roles in protecting against inflammation and clearing pathogens from the body. In this study, homologous compounds of IL-10 and IL-6 were identified in channel catfish, and their immune responses were analyzed. The CDS sequences of IL-10 and IL-6 were 549 bp and 642 bp, respectively, and showed the highest homology with Ameiurus melas. In addition, the expression of the IL-10 and IL-6 genes was ubiquitous in 10 tissues examined. IL-10 is highly expressed in the liver and slightly expressed in the gill. The high expression of the IL-6 gene was observed in the spleen, heart, and gonad, with the lowest levels in the liver. LPS, Poly(I:C), PHA, and PMA showed a highly significant increase in IL-10 and IL-6 expression 48 h after CCK stimulation (p < 0.01). Otherwise, Yersinia ruckeri, Streptococcus iniae, channel catfish virus, and deltamethrin induced IL-10 and IL-6 expression, varying in intensity between different organs. Our results suggest that IL-10 and IL-6 are involved in the immune response of the host against the pathogen.

Contribution of Epstein–Barr Virus Lytic Proteins to Cancer Hallmarks and Implications from Other Oncoviruses

Epstein–Barr virus (EBV) is a prevalent human gamma-herpesvirus that infects the majority of the adult population worldwide and is associated with several lymphoid and epithelial malignancies. EBV displays a biphasic life cycle, namely, latent and lytic replication cycles, expressing a diversity of viral proteins. Among the EBV proteins being expressed during both latent and lytic cycles, the oncogenic roles of EBV lytic proteins are largely uncharacterized. In this review, the established contributions of EBV lytic proteins in tumorigenesis are summarized according to the cancer hallmarks displayed. We further postulate the oncogenic properties of several EBV lytic proteins by comparing the evolutionary conserved oncogenic mechanisms in other herpesviruses and oncoviruses.

Functional Implications of Epstein-Barr Virus Lytic Genes in Carcinogenesis

Epstein-Barr virus (EBV) is associated with a diverse range of tumors of both lymphoid and epithelial origin. Similar to other herpesviruses, EBV displays a bipartite life cycle consisting of latent and lytic phases. Current dogma indicates that the latent genes are key drivers in the pathogenesis of EBV-associated cancers, while the lytic genes are primarily responsible for viral transmission. In recent years, evidence has emerged to show that the EBV lytic phase also plays an important role in EBV tumorigenesis, and the expression of EBV lytic genes is frequently detected in tumor tissues and cell lines. The advent of next generation sequencing has allowed the comprehensive profiling of EBV gene expression, and this has revealed the consistent expression of several lytic genes across various types of EBV-associated cancers. In this review, we provide an overview of the functional implications of EBV lytic gene expression to the oncogenic process and discuss possible avenues for future investigations.

Mechanism of N-0385 blocking SARS-CoV-2 to treat COVID-19 based on molecular docking and molecular dynamics

PURPOSE

2019 Coronavirus disease (COVID-19) has caused millions of confirmed cases and deaths worldwide. TMPRSS2-mediated hydrolysis and maturation of spike protein is essential for SARS-CoV-2 infection in vivo. The latest research found that a TMPRSS2 inhibitor called N-0385 could effectively prevent the infection of the SARS-CoV-2 and its variants. However, it is not clear about the mechanism of N-0385 treatment COVID-19. Therefore, this study used computer simulations to investigate the mechanism of N-0385 treatment COVID-19 by impeding SARS-CoV-2 infection.

METHODS

The GeneCards database was used to search disease gene targets, core targets were analyzed by PPI, GO and KEGG. Molecular docking and molecular dynamics were used to validate and analyze the binding stability of small molecule N-0385 to target proteins. The supercomputer platform was used to simulate and analyze the number of hydrogen bonds, binding free energy, stability of protein targets at the residue level, radius of gyration and solvent accessible surface area.

RESULTS

There were 4,600 COVID-19 gene targets from GeneCards database. PPI, GO and KEGG analysis indicated that signaling pathways of immune response and inflammation played crucial roles in COVID-19. Molecular docking showed that N-0385 could block SARS-CoV-2 infection and treat COVID-19 by acting on ACE2, TMPRSS2 and NLRP3. Molecular dynamics was used to demonstrate that the small molecule N-0385 could form very stable bindings with TMPRSS2 and TLR7.

CONCLUSION

The mechanism of N-0385 treatment COVID-19 was investigated by molecular docking and molecular dynamics simulation. We speculated that N-0385 may not only inhibit SARS-CoV-2 invasion directly by acting on TMPRSS2, ACE2 and DPP4, but also inhibit the immune recognition process and inflammatory response by regulating TLR7, NLRP3 and IL-10 to prevent SARS-CoV-2 invasion. Therefore, these results suggested that N-0385 may act through multiple targets to reduce SARS-CoV-2 infection and damage caused by inflammatory responses.

Study on the Mechanism of Improving HIV/AIDS Immune Function with Jian Aikang Concentrated Pill Based on Network Pharmacology Combined with Experimental Validation

Purpose

This study was the first to screen the active compounds of Jian Aikang Concentrated Pill (JAKCP) with network pharmacology, predict its potential targets, screen the signaling pathways, and combine with cellular experimental validation to explore the potential mechanism of JAKCP for the treatment of acquired immunodeficiency syndrome (AIDS).

Methods

The main compounds and targets of Chinese herbs in JAKCP were identified by TCMSP; the targets of AIDS were collected from Genecards, Online Mendelian Inheritance in Man (OMIM), Disgenet, Therapeutic Target Database (TTD) and Drugbank; the network of “Chinese herbs-active compounds-targets” for JAKCP was constructed by Cytoscape, and protein–protein interaction (PPI) network was constructed using STRING to generate the intersection targets, Metascape was conducted to analyze the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), and the network of “main active compounds-core targets-pathways” was constructed by Cytoscape. Finally, the effect of JAKCP on the survival rate of HIV pseudovirus-infected MT-4 cells was investigated by CCK-8 assay, and the predicted targets were verified by ELISA, qPCR and Western blot.

Results

A total of 147 active compounds of JAKCP were screened covering 351 targets and 416 AIDS disease targets were obtained, besides 140 intersection targets and 321 KEGG pathways were collected. Ultimately, quercetin, kaempferol, stigmasterol, beta-sitosterol, epigallocatechin gallate were identified as the important compounds, the core targets are HSP90AA1, IL-10, IL-6, TNF, IL-1β, TP53, and IL-1ɑ, and the biological pathways and processes mainly include T cell activation, regulation of DNA-binding transcription factor activity and apoptotic signaling pathway. Experiments on the targets of “T cell activation” demonstrated that JAKCP promotes the survival of HIV pseudovirus-infected MT-4 cells. Also, JAKCP down-regulated mRNA and protein levels of IL-1ɑ, IL-1β, and IL-6 while up-regulated mRNA and protein levels of IL-2, IL-6ST, and IL-10 in vitro.

Conclusion

JAKCP exerted regulatory immune functions through multi-component, multi-target and multi-pathway, thereby providing novel ideas and clues for the treatment of AIDS.

Ly6C hi monocytes balance regulatory and cytotoxic CD4 T cell responses to control virus-induced immunopathology

Gammaherpesviruses (γHVs) have coevolved with their host, leading to a remarkably high infection prevalence and establishment of latency. The lifelong persistence of γHVs in hosts appears to broadly shape host immunity, and we show here that pulmonary infection with Murid herpesvirus 4 (MuHV-4), a mouse γHV, drives the recruitment of Ly6C hi monocytes (MOs) into the airway, thereby modulating the host immune response. The absence of Ly6C hi MOs is associated with severe virus-induced immunopathology and the systemic release of inflammatory mediators. Mechanistically, MuHV-4–imprinted MOs recruit CD4 T cells to the airways and trigger immunosuppressive signaling pathways through the PD-L1/PD-1 axis, thereby dampening the deleterious activation of cytotoxic CD4 T cells. These results uncover a role for Ly6C hi MOs in modulating CD4 T cell functions and reveal pathways that could be targeted therapeutically to reduce detrimental immunopathological responses associated with respiratory viral infections.

Impact of FOXP3 gene polymorphisms and gene-environment interactions in asthma and atopy in a Brazilian population

BACKGROUND

Polymorphisms in genes related to the activation and development of regulatory T cells (Tregs), such as FOXP3, may be associated with asthma and atopy development. Additionally, environmental factors such as exposure to infections can modify the effect of these associations. This study evaluated the impact of polymorphisms in the FOXP3 on the risk of asthma and atopy as also gene-environment interactions in these outcomes.

METHODS

This study included 1,246 children from the SCAALA program, between 4 and 11 years of age. DNA was extracted from peripheral blood and eight SNPs (rs2280883, rs11465476, rs11465472, rs2232368, rs3761549, rs3761548, rs2232365 and rs2294021) were genotyped using the 2.5 HumanOmni Beadchip from Illumina (San Diego, California, USA) or TaqMan qRT-PCR.

RESULTS

The rs2232368 (Allele T) was positively associated with asthma symptoms (OR=1.95, CI=1.04 to 3.66, p = 0.040) and skin prick test (SPT) reactivity to aeroallergens (OR=2.31, CI=1.16 to 4.59, p = 0.017). The rs3761549 (Allele T) was positively associated with SPT reactivity (OR=1.44, CI=1.03 to 2.02, p = 0.034). The rs2280883 (Allele C) was negatively associated with specific IgE to aeroallergens (OR=0.83, CI=0.70 to 0.99, p = 0.040). Furthermore, the rs2280883 played a protective role in the development of atopy only in individuals seropositive to Epstein-Barr virus (EBV) infection (OR=0.74, CI=0.60 to 0.92, p = 0.003 and OR=0.74; 95% CI=0.61-0.91, p = 0.007 for SPT and slgE respectively), but not in individuals without EBV infection.

CONCLUSION

Polymorphisms in the FOXP3 gene were associated with the risk of atopy and asthma development in our population. In addition, EBV infection had an effect modifier of the observed association for rs2280883 variant.

Recent Progress on the Roles of Regulatory T Cells in IgG4-Related Disease

IgG4-related disease (RD) is a proposed concept of systemic inflammatory condition from Japanese researchers. Patients with IgG4-RD manifest several immunological and histological characterizations in the organs involved, including elevated levels of serum IgG4 and lympho-plasmacytic infiltration, storiform fibrosis, IgG4-positive plasma cells infiltration, and obstructive phlebitis. Nevertheless, the pathogenesis of IgG4-RD still remains unclear. It has been made clear that several immune cells with regulatory function play a vital part in several diseases. In particular, abnormalities in the function and proportion of regulatory T cells (Tregs) are implicated in several diseases, and their part in IgG4-RD has been investigated. This review offers an overview of the research in IgG4-RD related to Tregs. Herein, the basic information of Tregs, knowledge gained from animal models involving Tregs, and the role of IgG4-RD has been provided. We also included the immunological mechanisms of IgG4-RD based on the data accumulated so far in our hypothesis.

The Role of MIF and IL-10 as Molecular Yin-Yang in the Modulation of the Host Immune Microenvironment During Infections: African Trypanosome Infections as a Paradigm

African trypanosomes are extracellular flagellated unicellular protozoan parasites transmitted by tsetse flies and causing Sleeping Sickness disease in humans and Nagana disease in cattle and other livestock. These diseases are usually characterized by the development of a fatal chronic inflammatory disease if left untreated. During African trypanosome infection and many other infectious diseases, the immune response is mediating a see-saw balance between effective/protective immunity and excessive infection-induced inflammation that can cause collateral tissue damage. African trypanosomes are known to trigger a strong type I pro-inflammatory response, which contributes to peak parasitaemia control, but this can culminate into the development of immunopathologies, such as anaemia and liver injury, if not tightly controlled. In this context, the macrophage migration inhibitory factor (MIF) and the interleukin-10 (IL-10) cytokines may operate as a molecular “Yin-Yang” in the modulation of the host immune microenvironment during African trypanosome infection, and possibly other infectious diseases. MIF is a pleiotropic pro-inflammatory cytokine and critical upstream mediator of immune and inflammatory responses, associated with exaggerated inflammation and immunopathology. For example, it plays a crucial role in the pro-inflammatory response against African trypanosomes and other pathogens, thereby promoting the development of immunopathologies. On the other hand, IL-10 is an anti-inflammatory cytokine, acting as a master regulator of inflammation during both African trypanosomiasis and other diseases. IL-10 is crucial to counteract the strong MIF-induced pro-inflammatory response, leading to pathology control. Hence, novel strategies capable of blocking MIF and/or promoting IL-10 receptor signaling pathways, could potentially be used as therapy to counteract immunopathology development during African trypanosome infection, as well as during other infectious conditions. Together, this review aims at summarizing the current knowledge on the opposite immunopathological molecular “Yin-Yang” switch roles of MIF and IL-10 in the modulation of the host immune microenvironment during infection, and more particularly during African trypanosomiasis as a paradigm.

How Does Epstein–Barr Virus Interact With Other Microbiomes in EBV-Driven Cancers?

The commensal microbiome refers to a large spectrum of microorganisms which mainly consists of viruses and bacteria, as well as some other components such as protozoa and fungi. Epstein–Barr virus (EBV) is considered as a common component of the human commensal microbiome due to its spread worldwide in about 95% of the adult population. As the first oncogenic virus recognized in human, numerous studies have reported the involvement of other components of the commensal microbiome in the increasing incidence of EBV-driven cancers. Additionally, recent advances have also defined the involvement of host–microbiota interactions in the regulation of the host immune system in EBV-driven cancers as well as other circumstances. The regulation of the host immune system by the commensal microbiome coinfects with EBV could be the implications for how we understand the persistence and reactivation of EBV, as well as the progression of EBV-associated cancers, since majority of the EBV persist as asymptomatic carrier. In this review, we attempt to summarize the possible mechanisms for EBV latency, reactivation, and EBV-driven tumorigenesis, as well as casting light on the role of other components of the microbiome in EBV infection and reactivation. Besides, whether novel microbiome targeting strategies could be applied for curing of EBV-driven cancer is discussed as well.

IL-10 as a Th2 Cytokine: Differences Between Mice and Humans

The discovery of IL-10 more than 30 years ago marked the beginning of our understanding of how cytokines regulate immune responses, based on cross-regulation between Th1 and Th2 cytokines. Although multiple cell types were shown to produce IL-10, its identity as a Th2 cytokine remained strong because it was rigidly associated with Th2 clones in mice, whereas both Th1 and Th2 clones could secrete IL-10 in humans. However, as new Th1/Th2 cell functionalities emerged, anti-inflammatory action of IL-10 gained more attention than its inhibitory effect on Th1 cells, which may occur as an indirect consequence of suppression of APCs. This notion is also supported by the discovery of regulatory T cells, whose suppressor functions involve the mediation of IL-10, among other molecules. From this perspective, we discuss the functionalities of IL-10 by highlighting important differences between mice and humans with an emphasis on the Th1 and Th2 paradigm.

Interleukin-10 induces interferon-γ-dependent emergency myelopoiesis

In emergency myelopoiesis (EM), expansion of the myeloid progenitor compartment and increased myeloid cell production are observed and often mediated by the pro-inflammatory cytokine interferon gamma (IFN-γ). Interleukin-10 (IL-10) inhibits IFN-γ secretion, but paradoxically, its therapeutic administration to humans causes hematologic changes similar to those observed in EM. In this work, we use different in vivo systems, including a humanized immune system mouse model, to show that IL-10 triggers EM, with a significant expansion of the myeloid progenitor compartment and production of myeloid cells. Hematopoietic progenitors display a prominent IFN-γ transcriptional signature, and we show that IFN-γ mediates IL-10-driven EM. We also find that IL-10, unexpectedly, reprograms CD4 and CD8 T cells toward an activation state that includes IFN-γ production by these T cell subsets in vivo. Therefore, in addition to its established anti-inflammatory properties, IL-10 can induce IFN-γ production and EM, opening additional perspectives for the design of IL-10-based immunotherapies.

Viruses in colorectal cancer

Increasing evidence suggests that microorganisms might represent at least highly interesting cofactors in colorectal cancer (CRC) oncogenesis and progression. Still, associated mechanisms, specifically in colonocytes and their microenvironmental interactions, are still poorly understood. Although, currently, at least seven viruses are being recognized as human carcinogens, only three of these – Epstein–Barr virus (EBV), human papillomavirus (HPV) and John Cunningham virus (JCV) – have been described, with varying levels of evidence, in CRC. In addition, cytomegalovirus (CMV) has been associated with CRC in some publications, albeit not being a fully acknowledged oncovirus. Moreover, recent microbiome studies set increasing grounds for new hypotheses on bacteriophages as interesting additional modulators in CRC carcinogenesis and progression. The present Review summarizes how particular groups of viruses, including bacteriophages, affect cells and the cellular and microbial microenvironment, thereby putatively contributing to foster CRC. This could be achieved, for example, by promoting several processes – such as DNA damage, chromosomal instability, or molecular aspects of cell proliferation, CRC progression and metastasis – not necessarily by direct infection of epithelial cells only, but also by interaction with the microenvironment of infected cells. In this context, there are striking common features of EBV, CMV, HPV and JCV that are able to promote oncogenesis, in terms of establishing latent infections and affecting p53‐/pRb‐driven, epithelial–mesenchymal transition (EMT)‐/EGFR‐associated and especially Wnt/β‐catenin‐driven pathways. We speculate that, at least in part, such viral impacts on particular pathways might be reflected in lasting (e.g. mutational or further genomic) fingerprints of viruses in cells. Also, the complex interplay between several species within the intestinal microbiome, involving a direct or indirect impact on colorectal and microenvironmental cells but also between, for example, phages and bacterial and viral pathogens, and further novel species certainly might, in part, explain ongoing difficulties to establish unequivocal monocausal links between specific viral infections and CRC.

Human placental extract ameliorates methotrexate-induced hepatotoxicity in rats via regulating antioxidative and anti-inflammatory responses

Purpose

Methotrexate (MTX) induces hepatotoxicity, limiting its clinical efficacy as a widely known chemotherapy drug. In the current study, we examined the protective effect of human placenta extract (HPE) against MTX-induced liver damage in rats, as well as its ability to regulate antioxidative and anti-inflammatory liver responses.

Methods

Male rats were orally administered MTX at a daily dose of 5 mg/kg-body-weight in the presence or absence of HPE (10.08 mg/kg) for 2 weeks. We measured the biological effects of MTX and HPE on the levels of liver enzymes, lipid profile, lipid peroxidation, oxidative stress biomarkers, and cytokines [tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10)]. In addition, histological examination and histopathological scoring of liver tissues were performed.

Results

MTX-treated rats showed significantly increased (p < 0.001) liver enzyme levels for aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin, total cholesterol, and triglyceride levels. However, HPE supplementation in MTX-treated rats significantly decreased (p < 0.001) these elevated levels. HPE supplementation also significantly reduced the oxidative stress biomarker malondialdehyde (MDA), reversed the reduction in glutathione (GSH), and markedly increased the antioxidant enzyme activities of catalase (CAT) and superoxide dismutase (SOD) in the livers of MTX-treated rats. Furthermore, HPE supplementation significantly decreased the MTX-elevated levels of the pro-inflammatory cytokines TNF-α, IL-6, and IL-10. Histopathological examinations showed that MTX produced severe cellular damage and inflammatory lesions in liver tissues, while treatment with HPE improved hepatic histologic architecture.

Conclusion

HPE has the ability to ameliorate methotrexate-induced liver injury in rats by mechanisms that include boosting antioxidative responses and down-regulating MDA and pro-inflammatory cytokine production.

VEGF-C/VEGFR-3 signaling in macrophages ameliorates acute lung injury

RATIONALE

Successful recovery from acute lung injury requires inhibition of neutrophil influx and clearance of apoptotic neutrophils. However, the mechanisms underlying recovery remain unclear.

OBJECTIVES

We investigated the ameliorative effects of vascular endothelial growth factor receptor-3 (VEGFR-3)/VEGF-C signaling in macrophages in lipopolysaccharide-induced lung injury.

METHODS

Lipopolysaccharides were intranasally injected into wild-type and transgenic mice. Gain- and loss- of VEGF-C/VEGFR-3 signaling function experiments employed adenovirus-mediated intranasal delivery of VEGF-C (Ad-VEGF-C vector) and soluble VEGFR-3, or, anti-VEGFR-3 blocking antibodies and mice with a deletion of VEGFR-3 in myeloid cells.

MEASUREMENTS AND MAIN RESULTS

The early phase of lung injury was significantly alleviated by the overexpression of VEGF-C with increased levels of bronchoalveolar lavage fluid (BALF) interleukin (IL)-10, but worsened in the later phase by VEGFR-3 inhibition upon administration of Ad-sVEGFR-3 vector. Injection of anti-VEGFR-3 antibodies to the mice in the resolution phase inhibited recovery from lung injury. The VEGFR-3 deleted mice had a shorter survival time than littermates and more severe lung injury in the resolution phase. Alveolar macrophages in the resolution phase digested most of extrinsic apoptotic neutrophils, and VEGF-C/VEGFR-3 signaling increased efferocytosis via upregulation of integrin alpha v in the macrophages. We also found that incubation with BALF from acute respiratory distress syndrome (ARDS) patients, but not from controls, decreases VEGFR-3 expression and the efficiency of IL-10 expression and efferocytosis in human monocyte-derived macrophages.

CONCLUSIONS

VEGFR-3/VEGF-C signaling in macrophages ameliorates experimental lung injury. This mechanism may provide an explanation also for ARDS resolution.

Comparative Transcriptomics of IBD Patients Indicates Induction of Type 2 Immunity Irrespective of the Disease Ideotype

Inflammatory cytokines initiate and sustain the perpetuation of processes leading to chronic inflammatory conditions such as inflammatory bowel diseases (IBD). The nature of the trigger causing an inflammatory reaction decides whether type 1, type 17, or type 2 immune responses, typically characterized by the respective T- helper cell subsets, come into effect. In the intestine, Type 2 responses have been linked with mucosal healing and resolution upon an immune challenge involving parasitic infections. However, type 2 cytokines are frequently elevated in certain types of IBD in particular ulcerative colitis (UC) leading to the assumption that Th2 cells might critically support the pathogenesis of UC raising the question of whether such elevated type 2 responses in IBD are beneficial or detrimental. In line with this, previous studies showed that suppression of IL-13 and other type 2 related molecules in murine models could improve the outcomes of intestinal inflammation. However, therapeutic attempts of neutralizing IL-13 in ulcerative colitis patients have yielded no benefits. Thus, a better understanding of the role of type 2 cytokines in regulating intestinal inflammation is required. Here, we took a comparative transcriptomic approach to address how Th2 responses evolve in different mouse models of colitis and human IBD datasets. Our data show that type 2 immune-related transcripts are induced in the inflamed gut of IBD patients in both Crohn's disease and UC and across widely used mouse models of IBD. Collectively our data implicate that the presence of a type 2 signature rather defines a distinct state of intestinal inflammation than a disease-specific pathomechanism.

IL-10 in Mast Cell-Mediated Immune Responses: Anti-Inflammatory and Proinflammatory Roles

Mast cells (MCs) play critical roles in Th2 immune responses, including the defense against parasitic infections and the initiation of type I allergic reactions. In addition, MCs are involved in several immune-related responses, including those in bacterial infections, autoimmune diseases, inflammatory bowel diseases, cancers, allograft rejections, and lifestyle diseases. Whereas antigen-specific IgE is a well-known activator of MCs, which express FcεRI on the cell surface, other receptors for cytokines, growth factors, pathogen-associated molecular patterns, and damage-associated molecular patterns also function as triggers of MC stimulation, resulting in the release of chemical mediators, eicosanoids, and various cytokines. In this review, we focus on the role of interleukin (IL)-10, an anti-inflammatory cytokine, in MC-mediated immune responses, in which MCs play roles not only as initiators of the immune response but also as suppressors of excessive inflammation. IL-10 exhibits diverse effects on the proliferation, differentiation, survival, and activation of MCs in vivo and in vitro. Furthermore, IL-10 derived from MCs exerts beneficial and detrimental effects on the maintenance of tissue homeostasis and in several immune-related diseases including contact hypersensitivity, auto-immune diseases, and infections. This review introduces the effects of IL-10 on various events in MCs, and the roles of MCs in IL-10-related immune responses and as a source of IL-10.

Effects of Injectable Trace Minerals (ITMs) on Th1/Th2 Cytokine Balance of Newborn Calves with Tropical Theileriosis

Injectable trace minerals (ITMs) could provide a potential alternative way of trace mineral delivery for sick animals. Therefore, evaluation of ameliorative potentials of ITMs (copper, manganese, selenium, and zinc) on the circulating Th1/Th2 cytokine misbalance in Theileria annulata-infected calves was aimed. Forty-three T. annulata-infected newborn calves were randomly allocated into four groups: buparvaquone alone-treated group (BUPA), buparvaquone + oxytetracycline (BUPA + OXY)-treated group, buparvaquone + injectable trace minerals (BUPA + ITMs)-treated group, and BUPA + OXY + ITM-treated group. Blood samples were collected from each of the calves before the start of therapy (day 0) and on day 14 post-therapy. Serum contents of pro- and anti-inflammatory cytokines were estimated by bovine specific ELISA kits. On day 14 post-therapy, significant amelioration in the circulating levels of the studied cytokines was not observed in the calves treated with BUPA, while the calves treated with BUPA + OXY revealed significant (P ≤ 0.04) amelioration in the circulating tumour necrosis factor-α (TNF-α) level. The calves treated with BUPA + ITMs revealed significant (P ≤ 0.041) elevation in the circulating interferon-γ (IFN-γ) and significant (P ≤ 0.011) reduction in the interleukin-10 (IL-10) levels. Moreover, the calves treated with BUPA + OXY + ITMs revealed significant reduction in TNF-α (P ≤ 0.0001) and IL-10 (P ≤ 0.012) contents, and significant elevation in IFN-γ (P ≤ 0.0002) content on day 14 post-therapy. None of the treated calve group revealed significant alteration in the circulating level of transforming growth factor-β (TGF-β) on day 14 post-therapy. In conclusion, administration of ITMs to the therapeutic regimen of newborn calves with tropical theileriosis could be a promising therapeutic strategy. ITMs can be recommended for the amelioration of immunological misbalance due to tropical theileriosis in newborn calves.

Ross River Virus Immune Evasion Strategies and the Relevance to Post-viral Fatigue, and Myalgic Encephalomyelitis Onset

Ross River virus (RRV) is an endemic Australian arbovirus, and member of the Alphavirus family that also includes Chikungunya virus (CHIK). RRV is responsible for the highest prevalence of human disease cases associated with mosquito-borne transmission in Australia, and has long been a leading suspect in cases of post-viral fatigue syndromes, with extrapolation of this link to Myalgic Encephalomyelitis (ME). Research into RRV pathogenesis has revealed a number of immune evasion strategies, impressive for a virus with a genome size of 12 kb (plus strand RNA), which resonate with insights into viral pathogenesis broadly. Drawing from observations on RRV immune evasion, mechanisms of relevance to long term idiopathic fatigue are featured as a perspective on infection and eventual ME symptoms, which include considerations of; (1) selective pro-inflammatory gene suppression post antibody-dependent enhancement (ADE) of RRV infection, (2) Evidence from other virus families of immune disruption and evasion post-ADE, and (3) how virally-driven immune evasion may impact on mitochondrial function via target of rapamycin (TOR) complexes. In light of these RRV measures to counter the host immune - inflammatory responses, links to recent discoveries explaining cellular, immune and metabolomic markers of ME will be explored and discussed, with the implications for long-COVID post SARS-CoV-2 also considered. Compelling issues on the connections between virally-induced alterations in cytokine expression, for example, will be of particular interest in light of energy pathways, and how these perturbations manifest clinically.

Epstein Barr Virus and Autoimmune Responses in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease. Infections or infectious reactivation are potential triggers for initiation of autoimmunity and for SLE flares. Epstein-Barr virus (EBV) is gamma herpes virus that has been associated with several autoimmune diseases such as SLE, multiple sclerosis, Sjogren’s syndrome, and systemic sclerosis. In this review, we will discuss the recent advances regarding how EBV may contribute to immune dysregulation, and how these mechanisms may relate to SLE disease progression.

Epstein-Barr Virus and Systemic Autoimmune Diseases

Epstein-Barr Virus (EBV) is an extremely successful human herpes virus, which infects essentially all human beings at some time during their life span. EBV infection and the associated immune response results in production of antibodies (seroconversion), which occurs mainly during the first years of life, but may also happen during adolescence or later in life. Infection of adolescents can result in infectious mononucleosis, an acute serious condition characterized by massive lymphocytosis. Transmission of EBV mainly occurs through saliva but can rarely be spread through semen or blood, e.g. through organ transplantations and blood transfusions. EBV transmission through oral secretions results in infection of epithelial cells of the oropharynx. From the epithelial cells EBV can infect B cells, which are the major reservoir for the virus, but other cell types may also become infected. As a result, EBV can shuttle between different cell types, mainly B cells and epithelial cells. Moreover, since the virus can switch between a latent and a lytic life cycle, EBV has the ability to cause chronic relapsing/reactivating infections. Chronic or recurrent EBV infection of epithelial cells has been linked to systemic lupus erythematosus and Sjögren’s syndrome, whereas chronic/recurrent infection of B cells has been associated with rheumatoid arthritis, multiple sclerosis and other diseases. Accordingly, since EBV can shuttle between epithelial cells and B cells, the systemic autoimmune diseases often occur as overlapping syndromes with symptoms and characteristic autoantibodies (e.g. antinuclear antibodies and rheumatoid factors) reflecting epithelial and/or B cell infection.

IL-10 Signaling in the Tumor Microenvironment of Ovarian Cancer

Unlike other malignancies, ovarian cancer (OC) creates a complex tumor microenvironment with distinctive peritoneal ascites consisting of a mixture of several immunosuppressive cells which impair the ability of the patient's immune system to fight the disease. The poor survival rates observed in advanced stage OC patients and the lack of effective conventional therapeutic options have been attributed in large part to the immature dendritic cells (DCs), IL-10 secreting regulatory T cells, tumor-associated macrophages, myeloid-derived suppressor cells, and cancer stem cells that secrete inhibitory cytokines. This review highlights the critical role played by the intraperitoneal presence of IL-10 in the generation of an immunosuppressive tumor microenvironment. Further, the effect of antibody neutralization of IL-10 on the efficacy of DC and chimeric antigen receptor T-cell vaccines will be discussed. Moreover, we will review the influence of IL-10 in the promotion of cancer stemness in concert with the NF-κB signaling pathway with regard to OC progression. Finally, understanding the role of IL-10 and its crosstalk with various cells in the ascitic fluid may contribute to the development of novel immunotherapeutic approaches with the potential to kill drug-resistant OC cells while minimizing toxic side effects.

Development, phenotypes of immune cells in BTBR T+Itpr3tf/J mice

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition that is characterized by a lack of social interaction, decreased verbal and non-verbal communication skills, and stereotyped repetitive behavior. There is strong evidence that a dysregulated immune response may influence neurodevelopment and thus may have a role in the development of ASD. This study focuses on the characterization of immune cell phenotypes in the BTBR T⁺Itpr3^tf/J (BTBR) mouse strain, a widely used animal model for autism research. Our study demonstrated that BTBR mice have a different immune profile compared to C57BL/6J (B6) mice, which do not display ASD-like characteristics. Thymic cells of BTBR mice have more single positive (SP) CD4⁺ and CD8⁺ T cells and fewer double positive (DP) T cells than B6 mice. The development of T cells is increased in BTBR mice with regard to the double negative (DN4) population being much higher in BTBR mice. The spleens and blood of BTBR mice also have more T helper type 1 (Th1), T helper type 2 (Th2) and T regulatory (Treg) cells compared to B6 mice. Aire expression in the thymus and spleen of BTBR mice compared to B6 mice was equivalent and lower, respectively. The mature natural killer (NK) innate immune cell population in blood and spleen is lower in BTBR than B6 mice; NK cell development is blocked prior to the double positive (DN) CD11b⁺CD27⁺ stage in BTBR mice. Since BTBR mice have more CD4⁺ T cells and elevated numbers of Th1 (T-bet⁺) and Th2 (GATA3⁺) cells, their low defense against pathogen may be explained by the lower number of NK cells and the significantly lower Th1 to Th2 ratio. The elevated number of plasma cells and autoantibodies of BTBR mice may be due to less presence and function of splenic AIRE.

Biology and therapeutic potential of interleukin-10

The authors review the molecular mechanisms regulating IL-10 production and response and describe classic and novel functions of IL-10 in immune and non-immune cells. They further discuss the therapeutic potential of IL-10 in different diseases and the outstanding questions underlying an effective application of IL-10 in clinical settings.

The cytokine IL-10 is a key anti-inflammatory mediator ensuring protection of a host from over-exuberant responses to pathogens and microbiota, while playing important roles in other settings as sterile wound healing, autoimmunity, cancer, and homeostasis. Here we discuss our current understanding of the regulation of IL-10 production and of the molecular pathways associated with IL-10 responses. In addition to IL-10’s classic inhibitory effects on myeloid cells, we also describe the nonclassic roles attributed to this pleiotropic cytokine, including how IL-10 regulates basic processes of neural and adipose cells and how it promotes CD8 T cell activation, as well as epithelial repair. We further discuss its therapeutic potential in the context of different diseases and the outstanding questions that may help develop an effective application of IL-10 in diverse clinical settings.

The Regulatory Role of IL-10 in Neurodegenerative Diseases

IL-10, an immunosuppressive cytokine, is considered an important anti-inflammatory modulator of glial activation, preventing inflammation-mediated neuronal degeneration under pathological conditions. In this narrative review, we summarize recent insights about the role of IL-10 in the neurodegeneration associated with neuroinflammation, in diseases such as Multiple Sclerosis, Traumatic Brain Injury, Amyotrophic lateral sclerosis, Alzheimer’s Disease, and Parkinson’s Disease, focusing on the contribution of this cytokine not only in terms of protective action, but also as possibly responsible for clinical worsening. The knowledge of this double face of the same coin, regarding the biological role of the IL-10, could aid the development of targeted therapies useful for limiting neurodegenerative processes.

IL-10 and IL-22 in Mucosal Immunity: Driving Protection and Pathology

The barrier surfaces of the gastrointestinal tract are in constant contact with various microorganisms. Cytokines orchestrate the mucosal adaptive and innate immune cells in the defense against pathogens. IL-10 and IL-22 are the best studied members of the IL-10 family and play essential roles in maintaining mucosal homeostasis. IL-10 serves as an important regulator in preventing pro-inflammatory responses while IL-22 plays a protective role in tissue damage and contributes to pathology in certain settings. In this review, we focus on these two cytokines in the development of gastrointestinal diseases, including inflammatory bowel diseases (IBD) and colitis-associated cancer (CAC). We summarize the recent studies and try to gain a better understanding on how they regulate immune responses to maintain equilibrium under inflammatory conditions.

Role of cytokines in the clinical manifestation of exophthalmia in newborn calves with tropical theileriosis

The present study aimed to evaluate the pathology of the exophthalmia and the host-immune response in naturally Theileria annulata-infected calves. The newborn calves detected positive for theileriosis were grouped into calves with theileriosis and absence of exophthalmia (n = 30), and calves with theileriosis and the presence of exophthalmia (n = 13). Sixteen healthy calves, free from any haemoprotozoal infection, were kept as healthy controls. A significantly (P ≤ .001) higher circulating levels of tumour necrosis factor-α (TNF-α) and interleukin-10 (IL-10) were estimated in diseased calves with and without exophthalmia as compared to healthy controls. Contrarily, significantly (P ≤ .01) lower interferon-γ (IFN-γ) level was estimated in diseased calves. The diseased calves with exophthalmia revealed significantly higher levels of TNF-α (P ≤ .001) and IL-10 (P ≤ .006) as compared to the diseased calves without exophthalmia. The diseased calves were not found to have an elevated intraocular pressure; rather they had significantly (P ≤ .001) lower intraocular pressure compared to the healthy controls. An elevated systemic TNF-α level might be attributed to the exophthalmia in calves with tropical theileriosis. The elevated circulatory IL-10 and reduced IFN-γ levels could be one of the strategies of Theileria annulata to escape the host immunity.

SARS-CoV-2 infection: The role of cytokines in COVID-19 disease

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A wide range of cytokines are involved in the development of COVID-19 disease.

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Some of these biomolecules are related to the progression and even to the prognosis of the infection.

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Findings on the role of cytokine storm associated with SARS-CoV-2 infection can be useful in order to manage this highly virulent disease.

COVID-19 disease, caused by infection with SARS-CoV-2, is related to a series of physiopathological mechanisms that mobilize a wide variety of biomolecules, mainly immunological in nature. In the most severe cases, the prognosis can be markedly worsened by the hyperproduction of mainly proinflammatory cytokines, such as IL-1, IL-6, IL-12, IFN-γ, and TNF-α, preferentially targeting lung tissue. This study reviews published data on alterations in the expression of different cytokines in patients with COVID-19 who require admission to an intensive care unit. Data on the implication of cytokines in this disease and their effect on outcomes will support the design of more effective approaches to the management of COVID-19.

Role of Epstein-Barr Virus in Pathogenesis and Racial Distribution of IgA Nephropathy

IgA nephropathy (IgAN) is the dominant type of primary glomerulonephritis worldwide. However, IgAN rarely affects African Blacks and is uncommon in African Americans. Polymeric IgA1 with galactose-deficient hinge-region glycans is recognized as auto-antigen by glycan-specific antibodies, leading to formation of circulating immune complexes with nephritogenic consequences. Because human B cells infected in vitro with Epstein-Barr virus (EBV) secrete galactose-deficient IgA1, we examined peripheral blood B cells from adult IgAN patients, and relevant controls, for the presence of EBV and their phenotypic markers. We found that IgAN patients had more lymphoblasts/plasmablasts that were surface-positive for IgA, infected with EBV, and displayed increased expression of homing receptors for targeting the upper respiratory tract. Upon polyclonal stimulation, these cells produced more galactose-deficient IgA1 than did cells from healthy controls. Unexpectedly, in healthy African Americans, EBV was detected preferentially in surface IgM- and IgD-positive cells. Importantly, most African Blacks and African Americans acquire EBV within 2 years of birth. At that time, the IgA system is naturally deficient, manifested as low serum IgA levels and few IgA-producing cells. Consequently, EBV infects cells secreting immunoglobulins other than IgA. Our novel data implicate Epstein-Barr virus infected IgA⁺ cells as the source of galactose-deficient IgA1 and basis for expression of relevant homing receptors. Moreover, the temporal sequence of racial-specific differences in Epstein-Barr virus infection as related to the naturally delayed maturation of the IgA system explains the racial disparity in the prevalence of IgAN.

Gammaherpesviruses and B Cells: A Relationship That Lasts a Lifetime

Gammaherpesviruses are highly prevalent pathogens that establish life-long infection and are associated with diverse malignancies, including lymphoproliferative diseases and B cell lymphomas. Unlike other viruses that either do not infect B cells or infect B cells transiently, gammaherpesviruses manipulate physiological B cell differentiation to establish life-long infection in memory B cells. Disruption of such viral manipulation by genetic or environmental causes is likely to seed viral lymphomagenesis. In this review, we discuss physiological and unique host and viral mechanisms usurped by gammaherpesviruses to fine tune host B cell biology for optimal infection establishment and maintenance.

Functions and regulation of T cell-derived interleukin-10

Interleukin (IL)-10 is an essential anti-inflammatory cytokine and functions as a negative regulator of immune responses to microbial antigens. IL-10 is particularly important in maintaining the intestinal microbe-immune homeostasis. Loss of IL-10 promotes the development of inflammatory bowel disease (IBD) as a consequence of an excessive immune response to the gut microbiota. IL-10 also functions more generally to prevent excessive inflammation during the course of infection. Although IL-10 can be produced by virtually all cells of the innate and adaptive immune system, T cells constitute a non-redundant source for IL-10 in many cases. The various roles of T cell-derived IL-10 will be discussed in this review. Given that IL-10 is at the center of maintaining the delicate balance between effective immunity and tissue protection, it is not surprising that IL-10 expression is highly dynamic and tightly regulated. We summarize the environmental signals and molecular pathways that regulate IL-10 expression. While numerous studies have provided us with a deep understanding of IL-10 biology, the majority of findings have been made in murine models, prompting us to highlight gaps in our knowledge about T cell-derived IL-10 in the human system.

Alnus Sibirica Extracts Suppress the Expression of Inflammatory Cytokines Induced by Lipopolysaccharides, Tumor Necrosis Factor-α, and Interferon-γ in Human Dermal Fibroblasts

The effects of Alnus sibirica (AS) extracts on cytokine expression induced by inflammatory stimulants were examined in human dermal fibroblasts (HDFs) and RAW264.7 cells. The anti-oxidative effect and effect on cell viability of AS extracts were evaluated, and four extracts with the highest anti-oxidative effects were selected. HDFs and RAW264.7 cells were treated with inflammatory stimulants, and the expression of cytokines involved in acute (IL-6 and IL-10) and chronic (IL-18) inflammation, the initiation of the immune response (IL-33), and non-specific immune responses (IL-1β, IL-8, and TNF-α) were determined using a reverse-transcription polymerase chain reaction. LPS increased the expression of all the cytokines, except for IL-18; however, AS extracts, particularly AS2 and AS4, reduced this increase, and TNF-α treatment markedly increased the expression of cytokines related to non-specific immune responses. IFN-γ treatment induced no significant changes, except for increased IL-33 expression in HDFs. AS extracts inhibited the increase in the expression of IL-33 and other cytokines in HDFs. Thus, the exposure of HDFs and RAW264.7 cells to inflammatory stimulants increased the expression of cytokines related to all the inflammatory processes. HDFs are involved not only in simple tissue regeneration but also in inflammatory reactions in the skin. AS2 and AS4 may offer effective therapy for related conditions.

IL-10 Family Cytokines IL-10 and IL-22: from Basic Science to Clinical Translation

Cytokines are among the most important effector and messenger molecules in the immune system. They profoundly participate in immune responses during infection and inflammation, protecting against or contributing to diseases such as allergy, autoimmunity, and cancer. Manipulating cytokine pathways, therefore, is one of the most effective strategies to treat various diseases. IL-10 family cytokines exert essential functions to maintain tissue homeostasis during infection and inflammation through restriction of excessive inflammatory responses, upregulation of innate immunity, and promotion of tissue repairing mechanisms. Their important functions in diseases are supported by data from many preclinical models, human genetic studies, and clinical interventions. Despite significant efforts, however, there is still no clinically approved therapy through manipulating IL-10 family cytokines. Here, we summarize the recent progress in understanding the biology of this family of cytokines, suggesting more specific strategies to maneuver these cytokines for the effective treatment of inflammatory diseases and cancers.

Human cytomegalovirus IL-10 augments NK cell cytotoxicity

Human cytomegalovirus (HCMV) persistently infects most of the adult population with periods of productive and latent infection differentially orchestrated by multiple HCMV-encoded gene products. One HCMV gene (UL111a) encodes cmvIL-10, a virokine homologous to human IL (hIL)-10. Although the effects of cmvIL-10 on most human lymphocyte subsets have been extensively studied, its impact on NK cell function was unreported prior to this study. We investigated effects of short-term cmvIL-10 exposure on human NK cells and found it substantially enhanced NK cell cytotoxicity through natural cytotoxicity receptors NKp30 and NKp46 as well as through C-type lectin-like receptors NKG2C and NKG2D. Antibody-dependent cell-mediated cytotoxicity triggered through CD16 also increased significantly with short-term cmvIL-10 exposure. These effects of cmvIL-10 on NK cell cytotoxicity were rapid, dose dependent, neutralized by polyclonal anti-cmvIL-10 or monoclonal anti-IL-10 receptor (IL-10R) antibodies and independent of increased perforin synthesis or up-regulation of activating receptors. A low percentage (0.5-5.4%; n = 12) of NK cells expressed IL-10R and the impact of cmvIL-10 on NK cells degranulation following CD16 stimulation directly correlated with this percentage (P = 0.0218). Short-term exposure of human NK cells to cmvIL-10 did not introduce phenotypic changes reminiscent of NK adaptation to HCMV infection in vivo. Determining how expression of a viral protein that activates NK cells contributes to their function in vivo will increase understanding of HCMV infection and NK cell biology.

Viral replication and innate immunity of feline herpesvirus-1 virulence-associated genes in feline respiratory epithelial cells

Feline herpesvirus-1 (FHV-1) infection occurs worldwide and is a leading cause of respiratory and ocular diseases in cats. Current vaccines reduce the severity of symptoms but do not prevent infection and, therefore, do not provide defense against an establishment of latency and reactivation. We hypothesize that immunomodulation of FHV-1 is the cause of lack in protection and that deletion of virulence/immune modulatory genes of FHV-1 will enhance safety and immunogenicity. Our objective was to use feline respiratory epithelial cell (FREC) cultures to define in vitro growth characteristics and immunomodulation resulting from infection of FRECs with the virulent FHV-1 strain C27 (WT) and glycoprotein C-deletion (gC-), glycoprotein E-deletion (gE-), serine/threonine protein kinase-deletion (PK-), as well as gE and thymidine kinase-double-deletion (gE-TK-) mutants generated by bacterial artificial chromosome mutagenesis. Differentiated FRECs were mock inoculated or inoculated with WT, gC-, gE-, PK-, or gE-TK- mutants. Virus titration and real-time quantitative PCR assays were performed on samples collected at 1 hpi followed by 24 h intervals between 24 and 96 hpi to determine growth kinetics. Real-time PCR was used to quantitate IFNα, TNFα, IL-1β, IL-10, and TGFβ-specific mRNA levels. Immunoassays were performed to measure the protein levels of subsets of cytokines/chemokines secreted by FRECs. Inoculation of FRECs with gE-TK- resulted in significantly lower end-point titers than inoculation with WT or gE-. Both PK- and gC- inoculated FRECs also produced significantly lower end-point titers at 96 hpi than WT. Overall, intracellular virus titers were higher than those of extracellular virus. PCR results for viral DNA paralleled the virus titration results. Further, in contrast to WT inoculation, an increase in IFNα and IL-10 mRNA expression was not observed following inoculation with gE-TK- and PK-, but inoculation with gE-TK- and PK- did result in increased TGFβ expression in FRECs compared to responses following infection with WT. Moreover, gE-TK- and PK- blocked the inhibition of IL-8 and neutrophil chemoattractant (KC), which was observed following inoculation with WT. In summary, the results obtained in FRECs may be used to predict the safety and immunogenicity characteristics of these mutants in vivo. Our study highlights the value of the FREC system for studying replication kinetics/immune modulation factors of FHV-1 and screening prospective vaccine candidates before their use in experimental cats.

IL-10 promotes malignant pleural effusion in mice by regulating TH 1- and TH 17-cell differentiation and migration

The role of IL-10 in malignant pleural effusion (MPE) remains unknown. By using murine MPE models, we observed that an increase in pleural IL-10 was a significant predictor of increased risk of death. We noted that T_H 1- and T_H 17-cell content in MPE was higher in IL-10^-/- mice than in WT mice, and IL-10 deficiency promoted differentiation into T_H 1 but not into T_H 17 cells. A higher fraction of T_H 1 and T_H 17 cells in the MPE of IL-10^-/- mice expressed CXCR3 compared with WT mice. We also demonstrated that Lewis lung cancer and colon adenocarcinoma cells secreted large amounts of CXCL10, a ligand of CXCR3, which induced the migration of T_H 1 and T_H 17 cells into the MPE, and IFN-γ could promote this signaling cascade. Furthermore, intrapleural injection of mice with CXCL10-deficient tumor cells led to decreased T_H 1- and T_H 17-cell content in MPE, increased MPE volume, and reduced survival of MPE-bearing mice. Taken together, we demonstrated that IL-10 deficiency promoted T-cell differentiation into T_H 1 cells and upregulated the CXCR3-CXCL10 signaling pathway that recruits T_H 1 and T_H 17 cells into MPE, ultimately resulting in decreased MPE formation and longer survival time of mice-bearing MPE.

Regulation of Interleukin-10 Expression

Interleukin (IL)-10 is an essential anti-inflammatory cytokine that plays important roles as a negative regulator of immune responses to microbial antigens. Loss of IL-10 results in the spontaneous development of inflammatory bowel disease as a consequence of an excessive immune response to the gut microbiota. IL-10 also functions to prevent excessive inflammation during the course of infection. IL-10 can be produced in response to pro-inflammatory signals by virtually all immune cells, including T cells, B cells, macrophages, and dendritic cells. Given its function in maintaining the delicate balance between effective immunity and tissue protection, it is evident that IL-10 expression is highly dynamic and needs to be tightly regulated. The transcriptional regulation of IL-10 production in myeloid cells and T cells is the topic of this review. Drivers of IL-10 expression as well as their downstream signaling pathways and transcription factors will be discussed. We will examine in more detail how various signals in CD4⁺ T cells converge on common transcriptional circuits, which fine-tune IL-10 expression in a context-dependent manner.

Epstein Barr Virus Interleukin 10 Suppresses Anti-inflammatory Phenotype in Human Monocytes

Epstein Barr virus (EBV) is a gamma herpes virus associated with certain malignancies and autoimmune diseases. EBV maintains latency in B cells with occasional reactivation, in part by overcoming the host immune response with viral homologs of several human proteins. EBV interleukin 10 (vIL-10), a lytic phase protein, is a homolog of human IL-10 (hIL-10). The effect of vIL-10 on human monocytes, which are one of the first immune cells to respond to infection, is not known. To understand the role of vIL-10, monocytes from peripheral blood mononuclear cells were stimulated with hIL-10 or vIL-10. Human IL-10 stimulated STAT3 phosphorylation, which is required for suppression of inflammatory responses. However, vIL-10 induced significantly lower phosphorylation of STAT3 compared to hIL-10, and was less efficient in downregulating inflammatory genes. vIL-10 significantly reduced the expression of scavenger receptor CD163 on monocytes, suggesting inhibition of M2 polarization. Furthermore, uptake of apoptotic cells was reduced in vIL-10-stimulated monocytes compared to hIL-10-stimulated monocytes. A neutralizing antibody to IL-10R1 inhibited STAT3 phosphorylation induced by either hIL-10 or vIL-10, suggesting that vIL-10 signals through IL-10R1. Interestingly, vIL-10 suppressed hIL-10-induced STAT3 phosphorylation and inhibited upregulation of suppressors of inflammatory response by hIL-10. We further show that vIL-10 levels were significantly higher in plasma samples from systemic lupus erythematosus (SLE) patients compared to matched unaffected controls. vIL-10 levels did not correlate with hIL-10 levels, but were associated with levels of IgA antibodies to EBV viral capsid antigen, which is an indirect measure of viral reactivation. We propose that the suppression of hIL-10- induced anti-inflammatory genes by vIL-10, together with an increase in inflammatory gene expression, may overcome the anti-inflammatory effects of hIL-10 and exacerbate autoimmune responses in systemic autoimmune diseases.

Interleukin 10 mutant zebrafish have an enhanced interferon gamma response and improved survival against a Mycobacterium marinum infection

Tuberculosis ranks as one of the world’s deadliest infectious diseases causing more than a million casualties annually. IL10 inhibits the function of Th1 type cells, and IL10 deficiency has been associated with an improved resistance against Mycobacterium tuberculosis infection in a mouse model. Here, we utilized M. marinum infection in the zebrafish (Danio rerio) as a model for studying Il10 in the host response against mycobacteria. Unchallenged, nonsense il10^e46/e46 mutant zebrafish were fertile and phenotypically normal. Following a chronic mycobacterial infection, il10^e46/e46 mutants showed enhanced survival compared to the controls. This was associated with an increased expression of the Th cell marker cd4-1 and a shift towards a Th1 type immune response, which was demonstrated by the upregulated expression of tbx21 and ifng1, as well as the down-regulation of gata3. In addition, at 8 weeks post infection il10^e46/e46 mutant zebrafish had reduced expression levels of proinflammatory cytokines tnfb and il1b, presumably indicating slower progress of the infection. Altogether, our data show that Il10 can weaken the immune defense against M. marinum infection in zebrafish by restricting ifng1 response. Importantly, our findings support the relevance of M. marinum infection in zebrafish as a model for tuberculosis.

Regulation of lipoxygenase-1 and Dectin-1 on interleukin-10 in mouse Aspergillus fumigatus keratitis

AIM

To investigate the regulation of lipoxygenase (LOX)-1 and Dectin-1 on interleukin-10 (IL-10) production in mice with Aspergillus fumigatus (A. fumigatus) keratitis.

METHODS

The corneas of C57BL/6 mice were pretreated with LOX-1 inhibitor Poly(I) or Dectin-1 siRNA separately before the infection of A. fumigatus. Polymerase chain reaction (PCR) and Western blot were used to detect the expression of IL-10.

RESULTS

The mRNA and protein expressions of IL-10 were significantly increased in mice with A. fumigatus keratitis. Compared with the group pretreated with sterile water before infection, Poly(I) pretreatment suppressed IL-10 expression significantly. Compared with the group pretreated with scrambled siRNA before infection, Dectin-1 siRNA pretreatment significantly reduced IL-10 expression in response to A. fumigatus infection.

CONCLUSION

LOX-1 and Dectin-1 regulate IL-10 production in mouse A. fumigatus keratitis.

The Regulation of Inflammation by Innate and Adaptive Lymphocytes

Inflammation plays an essential role in the control of pathogens and in shaping the ensuing adaptive immune responses. Traditionally, innate immunity has been described as a rapid response triggered through generic and nonspecific means that by definition lacks the ability to remember. Recently, it has become clear that some innate immune cells are epigenetically reprogrammed or “imprinted” by past experiences. These “trained” innate immune cells display altered inflammatory responses upon subsequent pathogen encounter. Remembrance of past pathogen encounters has classically been attributed to cohorts of antigen-specific memory T and B cells following the resolution of infection. During recall responses, memory T and B cells quickly respond by proliferating, producing effector cytokines, and performing various effector functions. An often-overlooked effector function of memory CD4 and CD8 T cells is the promotion of an inflammatory milieu at the initial site of infection that mirrors the primary encounter. This memory-conditioned inflammatory response, in conjunction with other secondary effector T cell functions, results in better control and more rapid resolution of both infection and the associated tissue pathology. Recent advancements in our understanding of inflammatory triggers, imprinting of the innate immune responses, and the role of T cell memory in regulating inflammation are discussed.