Th22 cells control colon tumorigenesis through STAT3 and Polycomb Repression complex 2 signaling

IL-22 as a target for therapeutic intervention: Current knowledge on its role in various diseases

IL-22 has emerged as a crucial cytokine mediating protective response against pathogens and tissue regeneration. Dysregulated production of IL-22 has been shown to play a pivotal role in the pathogenesis of various diseases like malignant tumours, viral, cardiovascular, allergic and autoimmune disorders. Interleukin 22 belongs to IFN-IL-10 cytokine family. It is a major proinflammatory cytokine secreted by activated Th1 cells (Th22), though can also be secreted by many other immune cells like group 3 innate lymphocytes, γδ T cells, NK cells, NK T cells, and mucosal associated invariant T cells. Th22 cells exclusively release IL-22 but not IL-17 or IFN-γ (as Th1 cells releases IFN-γ along with IL-22 and Th17 cells releases IL-17 along with IL-22) and also express aryl hydrocarbon receptor as the key transcription factor. Th22 cells also exhibit expression of chemokine receptor CCR6 and skin-homing receptors CCR4 and CCR10 indicating the involvement of this subset in bolstering epithelial barrier immunity and promoting secretion of antimicrobial peptides (AMPs) from intestinal epithelial cells. The function of IL-22 is modulated by IL-22 binding protein (binds to IL-22 and inhibits it binding to its cell surface receptor); which serves as a competitor for IL-22R1 chain of IL-22 receptor. The pathogenic and protective nature of the Th22 cells is modulated both by the site of infected tissue and the type of disease pathology. This review aims to discuss key features of IL-22 biology, comparisons between IL and 22 and IFN-γ and its role as a potential immune therapy target in different maladies.

Research progress on Th22 cells and related cytokines in tumors: current status and future perspectives

Th22 cells are a newly identified subpopulation of CD4+ T lymphocytes distinct from Th1, Th2, and Th17 cells, which secretes mainly interleukin-22 (IL-22), in addition to a variety of other cytokines. The function of Th22 cells in tumors is mainly realized through IL-22, which can activate JAK/STAT and MAPK cell signaling pathways, thereby regulating the anti-tumor immune response of the body. The main function of Th22 cells is to participate in mucosal defense, tissue repair, and wound healing. However, controversial data have shown that overexpression of IL-22 can lead to pathological changes under inflammatory conditions and tumor progression. In this review, we searched the PubMed and Web of Science databases for articles and reviews published before May 6, 2022, using the keywords "Th22 cells, T helper 22 cells, cancer, tumor", and conducted a comprehensive review of the relevant literature. In addition, this article offers an overview of the relevant findings on the function of Th22 cells in tumors published in recent years, along with a more comprehensive analysis of the functions and mechanisms of Th22 cells in tumors. This article will hopefully inspire new future directions in the research on cancer therapy.

Integration of single sample and population analysis for understanding immune evasion mechanisms of lung cancer

A deep understanding of the complex interaction mechanism between the various cellular components in tumor microenvironment (TME) of lung adenocarcinoma (LUAD) is a prerequisite for understanding its drug resistance, recurrence, and metastasis. In this study, we proposed two complementary computational frameworks for integrating multi-source and multi-omics data, namely ImmuCycReg framework (single sample level) and L0Reg framework (population or subtype level), to carry out difference analysis between the normal population and different LUAD subtypes. Then, we aimed to identify the possible immune escape pathways adopted by patients with different LUAD subtypes, resulting in immune deficiency which may occur at different stages of the immune cycle. More importantly, combining the research results of the single sample level and population level can improve the credibility of the regulatory network analysis results. In addition, we also established a prognostic scoring model based on the risk factors identified by Lasso-Cox method to predict survival of LUAD patients. The experimental results showed that our frameworks could reliably identify transcription factor (TF) regulating immune-related genes and could analyze the dominant immune escape pathways adopted by each LUAD subtype or even a single sample. Note that the proposed computational framework may be also applicable to the immune escape mechanism analysis of pan-cancer.

EZH2: Its regulation and roles in immune disturbance of SLE

The pathogenesis of systemic lupus erythematosus (SLE) is related to immune homeostasis imbalance. Epigenetic mechanisms have played a significant role in breaking immune tolerance. Enhancer of zeste homolog 2 (EZH2), the specific methylation transferase of lysine at position 27 of histone 3, is currently found to participate in the pathogenesis of SLE through affecting multiple components of the immune system. This review mainly expounds the mechanisms underlying EZH2-mediated disruption of immune homeostasis in SLE patients, hoping to provide new ideas in the pathogenesis of SLE and new targets for future treatment.

Role of IL-22 in intestinal microenvironment and potential targeted therapy through diet

IL-22 is a type 2 receptor cytokine in IL-10 family. IL-22 is usually secreted by innate and adaptive immune cells and takes its effects on non-hematopoietic cells. Through activate STAT3 pathway, IL-22 plays an important role in infection clearance and tissue regeneration, which is critical for barrier integrate and homeostasis. Abnormal activation of IL-22 signal was observed in inflammation diseases, autoimmune diseases, and cancers. We review the recent discoveries about the mechanism and regulation of IL-22 signal pathway from the perspective of intestinal micro-environment. Diet-based IL-22 target therapeutic strategies and their potential clinical significance will also be discussed.

Interleukin-22 in Renal Protection and Its Pathological Role in Kidney Diseases

Chronic kidney injury has gradually become a worldwide public health problem currently affecting approximately 10% of the population and can eventually progress to chronic end-stage renal disease characteristic by the result of epithelial atrophy. Interleukin-22 (IL-22) is a cytokine produced by activated immune cells, while acting mainly on epithelial cells ranging from innate immune response to tissue regeneration to maintain barrier integrity and promote wound healing. Accumulating data suggests that IL-22 has emerged as a fundamental mediator of epithelial homeostasis in the kidney through promoting tissue repair and regeneration, inhibiting oxidative stress, and producing antimicrobial peptides. Binding of IL-22 to its transmembrane receptor complex triggers janus kinase/tyrosine kinase 2 phosphorylation, which further activates a number of downstream cascades, including signal transducer and activator of transcription 3, MAP kinase, and protein kinase B, and initiates a wide array of downstream effects. However, the activation of the IL-22 signaling pathways promotes the activation of complement systems and enhances the infiltration of chemokines, which does harm to the kidney and may finally result in chronic renal failure of different autoimmune kidney diseases, including lupus nephritis, and IgA nephropathy. This review describes current knowledge of the basic features of IL-22, including structure, cellular origin and associated signaling pathways. Also, we summarize the latest progress in understanding the physiological and pathological effects of IL-22 in the kidney, suggesting the potential strategies for the specific application of this cytokine in the treatment of kidney disease.

The role of Th22 cells, from tissue repair to cancer progression

CD4⁺ T helper (Th) cells play a significant role in modulating host defense. In the presence of lineage specific cytokine cocktail, Naive CD4⁺ T cells can differentiate into several categories with distinct cytokines profile and effector functions. Th22 cells are a recently identified subset of CD4⁺ T cell, which differentiate from Naive CD4⁺ T in the presence of IL-6 and TNF-α. Th22 characterized by the production of interleukin-22 (IL-22) and expression of aryl hydrocarbon receptor (AHR). The main function of Th22 cells is to participate in mucosal defense, tissue repair, and wound healing. However, controversial data have shown that overexpression of IL-22 can lead to pathological changes under inflammatory conditions and tumor progression. This review summarizes our knowledge about the role of Th22 and IL-22 cells in tumor progression through induction of inflammation.

Emerging Complexity in CD4+T Lineage Programming and Its Implications in Colorectal Cancer

The intestinal immune system has the difficult task of protecting a large environmentally exposed single layer of epithelium from pathogens without allowing inappropriate inflammatory responses. Unmitigated inflammation drives multiple pathologies, including the development of colorectal cancer. CD4⁺T cells mediate both the suppression and promotion of intestinal inflammation. They comprise an array of phenotypically and functionally distinct subsets tailored to a specific inflammatory context. This diversity of form and function is relevant to a broad array of pathologic and physiologic processes. The heterogeneity underlying both effector and regulatory T helper cell responses to colorectal cancer, and its impact on disease progression, is reviewed herein. Importantly, T cell responses are dynamic; they exhibit both quantitative and qualitative changes as the inflammatory context shifts. Recent evidence outlines the role of CD4⁺T cells in colorectal cancer responses and suggests possible mechanisms driving qualitative alterations in anti-cancer immune responses. The heterogeneity of T cells in colorectal cancer, as well as the manner and mechanism by which they change, offer an abundance of opportunities for more specific, and likely effective, interventional strategies.

New Findings on Autoimmune Etiology of Idiopathic Granulomatous Mastitis: Serum IL-17, IL-22 and IL-23 Levels of Patients

BACKGROUND

Idiopathic Granulomatous Mastitis (IGM) is a benign chronic inflammatory breast disease that mimics breast cancer, and the etiopathogenesis has not yet been fully evaluated. Autoimmunity has received the most focus as a possible etiology. Our aim in this prospective clinical study was to investigate the possible association between the cytokines, interleukin IL-17, IL-22, IL-23 and IGM.

MATERIALS AND METHODS

The current study was conducted in 26 women with histopathologically diagnosed IGM, and 15 control women of reproductive age having no breast disease history. Blood samples were collected, and serum concentrations of IL-17, IL-22, and IL-23 were determined.

RESULTS

In the analysis of variables, the patients with IGM and the control group had statistically significant differences between serum IL-22 titers (p = 0.0378) and IL-23 titers (p = 0.0469. No statistically significant difference was found between IGM patients and the control group in serum IL-17 titers (p = 0.9724).

CONCLUSION

The results of the current study, especially pertaining to serum IL-22 and IL-23 levels, support the etiopathogenesis of IGM in favor of the autoinflammatory thesis. Nevertheless, this thesis should be supported by a large case number and prospective clinical studies.

Interleukin-22 promotes PD-L1 expression via STAT3 in colon cancer cells

Blocking the expression of programmed cell death ligand 1 (PD-L1) is a promising approach for the treatment of colon cancer. The binding of PD-L1 to its receptor programmed cell death 1 (PD-1) on immune cells leads to the apoptosis of activated T cells and causes immune escape. However, there is a limited number of patients with colon cancer that can benefit from the inhibition of PD-L1, and the regulation of PD-L1 expression is poorly understood in colon cancer. The present study demonstrated that interleukin-22 (IL-22) and PD-L1 were upregulated in colon cancer tissues and there was a positive correlation between IL-22 expression and PD-L1 expression. In the present study, exogenous IL-22 was found to upregulate PD-L1 expression via the signal transducer and activator of transcription 3 signaling pathway in human colon cancer cells (DLD-1 and primary colon cancer cells). The results of the present study revealed a novel regulatory mechanism of PD-L1 expression in colon cancer, which provides a theoretical basis for decreasing the immune tolerance of colon cancer via IL-22 overexpression.

Extracellular vesicles as antigen carriers for novel vaccination avenues

Antigen delivery has always been a challenge in scientific practice of vaccine formulation. Yet, mammalian extracellular vesicles (EVs) or bacterial membrane vesicles (MVs) provide an innovative avenue for safe and effective delivery of antigenic material. They include intrinsically loaded antigens from EV-secreting cells or extrinsically loaded antigens onto pre-formed vesicles. Interestingly, many studies shed light on potential novel anti-cancer vaccination immunotherapy for therapeutic applications from mammalian cell host-derived EVs, as well as conventional vaccination for prophylactic applications using bacterial cell-derived MVs against infectious diseases. Here, we discuss the rationale, status quo and potential for both vaccine applications using EVs.

IL-22-mediates Cross-talk between Tumor Cells and Immune Cells Associated with Favorable Prognosis in Human Colorectal Cancer

The positive prognostic role of the immune environment in colorectal cancer is widely accepted. However, there are few data about the prognostic significance of interleukin-22 in human colorectal cancer which is still debated. In our study we could demonstrate for the first time a positive prognostic role of interleukin-22 in human colorectal cancer relying on its capacity to induce in tumor cells the production of chemokines recruiting into the tumor microenvironment neutrophils associated with a favorable clinical outcome.

The tumor-promoting effects of the adaptive immune system: a cause of hyperprogressive disease in cancer?

Adaptive antitumor immune responses, either cellular or humoral, aim at eliminating tumor cells expressing the cognate antigens. There are some instances, however, where these same immune responses have tumor-promoting effects. These effects can lead to the expansion of antigen-negative tumor cells, tumor cell proliferation and tumor growth, metastatic dissemination, resistance to antitumor therapy and apoptotic stimuli, acquisition of tumor-initiating potential and activation of various forms of survival mechanisms. We describe the basic mechanisms that underlie tumor-promoting adaptive immune responses and try to identify the variables that induce the switching of a tumor-inhibitory, cellular or humoral immune response, into a tumor-promoting one. We suggest that tumor-promoting adaptive immune responses may be at the origin of at least a fraction of hyperprogressive diseases (HPD) that are observed in cancer patients during therapy with immune checkpoint inhibitors (ICI) and, less frequently, with single-agent chemotherapy. We also propose the use of non-invasive biomarkers allowing to predict which patients may undergo HPD during ICI and other forms of antitumor therapy. Eventually, we suggest possibilities of therapeutic intervention allowing to inhibit tumor-promoting adaptive immune responses.

Infiltration by IL22-Producing T Cells Promotes Neutrophil Recruitment and Predicts Favorable Clinical Outcome in Human Colorectal Cancer

Immune cell infiltration in colorectal cancer effectively predicts clinical outcome. IL22, produced by immune cells, plays an important role in inflammatory bowel disease, but its relevance in colorectal cancer remains unclear. Here, we addressed the prognostic significance of IL22+ cell infiltration in colorectal cancer and its effects on the composition of tumor microenvironment. Tissue microarrays (TMA) were stained with an IL22-specific mAb, and positive immune cells were counted by expert pathologists. Results were correlated with clinicopathologic data and overall survival (OS). Phenotypes of IL22-producing cells were assessed by flow cytometry on cell suspensions from digested specimens. Chemokine production was evaluated in vitro upon colorectal cancer cell exposure to IL22, and culture supernatants were used to assess neutrophil migration in vitro Evaluation of a testing (n = 425) and a validation TMA (n = 89) revealed that high numbers of IL22 tumor-infiltrating immune cells were associated with improved OS in colorectal cancer. Ex vivo analysis indicated that IL22 was produced by CD4+ and CD8+ polyfunctional T cells, which also produced IL17 and IFNγ. Exposure of colorectal cancer cells to IL22 promoted the release of the neutrophil-recruiting chemokines CXCL1, CXCL2, and CXCL3 and enhanced neutrophil migration in vitro Combined survival analysis revealed that the favorable prognostic significance of IL22 in colorectal cancer relied on the presence of neutrophils and was enhanced by T-cell infiltration. Altogether, colorectal cancer-infiltrating IL22-producing T cells promoted a favorable clinical outcome by recruiting beneficial neutrophils capable of enhancing T-cell responses.

Activation of Cannabinoid Receptor 2 Prevents Colitis-Associated Colon Cancer through Myeloid Cell De-activation Upstream of IL-22 Production

Intestinal disequilibrium leads to inflammatory bowel disease (IBD), and chronic inflammation predisposes to oncogenesis. Antigen-presenting dendritic cells (DCs) and macrophages can tip the equilibrium toward tolerance or pathology. Here we show that delta-9-tetrahydrocannabinol (THC) attenuates colitis-associated colon cancer and colitis induced by anti-CD40. Working through cannabinoid receptor 2 (CB2), THC increases CD103 expression on DCs and macrophages and upregulates TGF-β1 to increase T regulatory cells (Tregs). THC-induced Tregs are necessary to remedy systemic IFNγ and TNFα caused by anti-CD40, but CB2-mediated suppression of APCs by THC quenches pathogenic release of IL-22 and IL-17A in the colon. By examining tissues from multiple sites, we confirmed that THC affects DCs, especially in mucosal barrier sites in the colon and lungs, to reduce DC CD86. Using models of colitis and systemic inflammation we show that THC, through CB2, is a potent suppressor of aberrant immune responses by provoking coordination between APCs and Tregs.

A Double Edged Sword Role of Interleukin-22 in Wound Healing and Tissue Regeneration

Wound healing and tissue regeneration is an intricate biological process that involves repair of cellular damage and maintenance of tissue integrity. Cascades involved in wound healing and tissue regeneration highly overlap with cancer causing pathways. Usually, subsequent tissue damage events include release of a number of cytokines to accomplish post-trauma restoration. IL-22 is one of the cytokines that are immediately produced to initiate immune response against several tissue impairments. IL-22 is a fundamental mediator in inflammation, mucous production, protective role against pathogens, wound healing, and tissue regeneration. However, accumulating evidence suggests pivotal role of IL-22 in instigation of various cancers due to its pro-inflammatory and tissue repairing activity. In this review, we summarize how healing effects of IL-22, when executed in an uncontrollable fashion can lead to carcinogenesis.

TH9, TH17, and TH22 Cell Subsets and Their Main Cytokine Products in the Pathogenesis of Colorectal Cancer

In recent years, several newly identified T helper (T_H) cell subsets, such as T_H9, T_H17, and T_H22 cells, and their respective cytokine products, IL-9, IL-17, and IL-22, have been reported to play critical roles in the development of chronic inflammation in the colorectum. Since chronic inflammation is a potent driving force for the development of human colorectal cancer (CRC), the contributions of T_H9/IL-9, T_H17/IL-17, and T_H22/IL-22 in the pathogenesis of CRC have recently become an increasingly popular area of scientific investigation. Extensive laboratory and clinical evidence suggests a positive relationship between these new T_H subsets and the growth and formation of CRC, whereas, administration of IL-9, IL-17, and IL-22 signaling inhibitors can significantly alter the formation of colorectal chronic inflammation or CRC lesions in animal models, suggesting that blocking these cytokine signals might represent promising immunotherapeutic strategies. This review summarizes recent findings and currently available data for understanding the vital role and therapeutic significance of T_H9/IL-9, T_H17/IL-17, and T_H22/IL-22 in the development of colorectal tumorigenesis.

Significant association of EED promoter hypomethylation with colorectal cancer

Colorectal cancer (CRC) is one of the most common and serious types of malignancy worldwide. The embryonic ectoderm development (EED) gene is important to maintain transcriptional repressive states of genes over successive cell generations. The present study aimed to investigate the association between EED methylation and CRC. A total of 111 CRC tissue samples, 111 paired para-tumor tissues and 20 colorectal normal tissues were obtained for EED methylation assay, which was performed using a quantitative methylation-specific polymerase chain reaction. The percentage of methylated reference was calculated to represent the DNA methylation level. A dual-luciferase reporter gene assay was used to detect the gene promoter activity of a EED fragment. The current results revealed a significant difference in the EED methylation levels among tumor, para-tumor and normal colorectal tissues (tumor vs. para-tumor vs. normal, 5.03±4.61 vs. 8.65±11.50 vs. 40.12±45.31; F=45.014; P<0.0001). The dual-luciferase reporter gene assay demonstrated that the transcriptional activity of recombinant pGL3-EED plasmid was significantly higher compared with that of the pGL3-Basic control vector (fold-change, 3.15; P=0.014), which suggests the EED fragment can promote gene expression. In conclusion, the present study demonstrated that EED hypomethylation may be an important factor associated with CRC.

Reparative T lymphocytes in organ injury

Acute organ injuries such as acute cerebrovascular accidents, myocardial infarction, acute kidney injury, acute lung injury, and others are among the leading causes of death worldwide. Dysregulated or insufficient organ repair mechanisms limit restoration of homeostasis and contribute to chronic organ failure. Studies reveal that both humans and mice harness potent non-stem cells that are capable of directly or indirectly promoting tissue repair. Specific populations of T lymphocytes have emerged as important reparative cells with context-specific actions. These T cells can resolve inflammation and secrete reparative cytokines and growth factors as well as interact with other immune and stromal cells to promote the complex and active process of tissue repair. This Review focuses on the major populations of T lymphocytes known to mediate tissue repair, their reparative mechanisms, and the diseases in which they have been implicated. Elucidating and harnessing the mechanisms that promote the reparative functions of these T cells could greatly improve organ dysfunction after acute injury.

Human Gut-Associated Natural Killer Cells in Health and Disease

It is well established that natural killer (NK) cells are involved in both innate and adaptive immunity. Indeed, they can recognize molecules induced at the cell surface by stress signals and virus infections. The functions of NK cells in the gut are much more complex. Gut NK cells are not precisely organized in lymphoid aggregates but rather scattered in the epithelium or in the stroma, where they come in contact with a multitude of antigens derived from commensal or pathogenic microorganisms in addition to components of microbiota. Furthermore, NK cells in the bowel interact with several cell types, including epithelial cells, fibroblasts, macrophages, dendritic cells, and T lymphocytes, and contribute to the maintenance of immune homeostasis and development of efficient immune responses. NK cells have a key role in the response to intestinal bacterial infections, primarily through production of IFNγ, which can stimulate recruitment of additional NK cells from peripheral blood leading to amplification of the anti-bacterial immune response. Additionally, NK cells can have a role in the pathogenesis of gut autoimmune inflammatory bowel diseases (IBDs), such as Crohn's Disease and Ulcerative Colitis. These diseases are considered relevant to the generation of gastrointestinal malignancies. Indeed, the role of gut-associated NK cells in the immune response to bowel cancers is known. Thus, in the gut immune system, NK cells play a dual role, participating in both physiological and pathogenic processes. In this review, we will analyze the known functions of NK cells in the gut mucosa both in health and disease, focusing on the cross-talk among bowel microenvironment, epithelial barrier integrity, microbiota, and NK cells.

DNA methylation-regulated and tumor-suppressive roles of miR-487b in colorectal cancer via targeting MYC, SUZ12, and KRAS

Human colorectal cancer (CRC), characterized by its high morbidity and lethality, seriously threatens human health and lives. MicroRNA‐487b (miR‐487b) is currently reported to be aberrantly expressed in several tumors, but the detailed functions and underlying mechanisms of miR‐487b in CRC remain unclear. Here, we found that miR‐487b is downregulated in CRC cell lines and is markedly decreased in tumor specimens derived from CRC patients. MiR‐487b inhibits cell proliferation, migration and invasion and promotes the apoptosis of CRC cells in vitro. Statistical analysis of clinical samples indicates that miR‐487b may serve as a biomarker for early CRC diagnosis. Inverse correlations between the expression levels of MYC, SUZ12, and KRAS and that of miR‐487b exist in vitro and in CRC patient tissue specimens. Further experiments demonstrated the regulatory effects of miR‐487b on MYC, SUZ12, and KRAS, and the disruption of these genes partially restores the miR‐487b inhibitor‐induced phenotype. Additionally, miR‐487b promoter region is in a DNA hypermethylated condition and the DNA methyltransferase inhibitor 5‐aza‐2’‐deoxycytidine (5‐Aza) increases the levels of miR‐487b but suppresses the expression of MYC, SUZ12, and KRAS in a time‐ and concentration‐dependent manner in CRC cells. Collectively, miR‐487b is regulated by DNA methylation and it functions as a tumor suppressor in CRC mainly through targeting MYC, SUZ12, and KRAS. Our study provides insight into the regulatory network in CRC cells, offering a new target for treating CRC patients.

Chemokine Heterocomplexes and Cancer: A Novel Chapter to Be Written in Tumor Immunity

Infiltrating immune cells are a key component of the tumor microenvironment and play central roles in dictating tumor fate, either promoting anti-tumor immune responses, or sustaining tumor growth, angiogenesis and metastasis. A distinctive microenvironment is often associated to different tumor types, with substantial differences in prognosis. The production of a variety of chemotactic factors by cancer and stromal cells orchestrates cell recruitment, local immune responses or cancer progression. In the last decades, different studies have highlighted how chemotactic cues, and in particular chemokines, can act as natural antagonists or induce synergistic effects on selective receptors by forming heterocomplexes, thus shaping migratory responses of immune cells. A variety of chemokines has been described to be able to form heterocomplexes both in vitro and in vivo under inflammatory conditions, but nowadays little is known on the presence and relevance of heterocomplexes in the tumor microenvironment. In recent years, the alarmin HMGB1, which can be massively released within the tumor microenvironment, has also been described to form a complex with the chemokine CXCL12 enhancing CXCR4-mediated signaling, thus providing an additional regulation of the activity of the chemokine system. In the present review, we will discuss the current knowledge on the synergy occurring between chemokines or inflammatory molecules, and describe the multiple functions exerted by the chemokines expressed in the tumor microenvironment, pointing our attention to the synergism as a possible modulator of tumor suppression or progression.

IL22 Promotes Kras-Mutant Lung Cancer by Induction of a Protumor Immune Response and Protection of Stemness Properties

Somatic KRAS mutations are the most common oncogenic variants in lung cancer and are associated with poor prognosis. Using a Kras-induced lung cancer mouse model, CC-LR, we previously showed a role for inflammation in lung tumorigenesis through activation of the NF-κB pathway, along with induction of interleukin 6 (IL6) and an IL17-producing CD4+ T-helper cell response. IL22 is an effector molecule secreted by CD4+ and γδ T cells that we previously found to be expressed in CC-LR mice. IL22 mostly signals through the STAT3 pathway and is thought to act exclusively on nonhematopoietic cells with basal IL22 receptor (IL22R) expression on epithelial cells. Here, we found that higher expression of IL22R1 in patients with KRAS-mutant lung adenocarcinoma was an independent indicator of poor recurrence-free survival. We then showed that genetic ablation of Il22 in CC-LR mice (CC-LR/IL22KO mice) caused a significant reduction in tumor number and size. This was accompanied by significantly lower tumor cell proliferation, angiogenesis, and STAT3 activation. Il22 ablation was also associated with significant reduction in lung-infiltrating inflammatory cells and expression of protumor inflammatory cytokines. Conversely, this was accompanied with increased antitumor Th1 and cytotoxic CD8+ T-cell responses, while suppressing the protumor immunosuppressive T regulatory cell response. In CC-LR/IL22KO mice, we found significantly reduced expression of core stemness genes and the number of prototypical SPC+CCSP+ stem cells. Thus, we conclude that IL22 promotes Kras-mutant lung tumorigenesis by driving a protumor inflammatory microenvironment with proliferative, angiogenic, and stemness contextual cues in epithelial/tumor cells. Cancer Immunol Res; 6(7); 788-97. ©2018 AACR.

The Imbalance between Foxp3+Tregs and Th1/Th17/Th22 Cells in Patients with Newly Diagnosed Autoimmune Hepatitis

This study is aimed at examining the potential role of regulatory T- (Treg-) Th1-Th17-Th22 cells in the pathogenic process of autoimmune hepatitis (AIH). The numbers of Foxp3⁺Tregs and Th1, Th17, and Th22 cells were measured in 32 AIH patients using flow cytometry. Moreover, a murine model of experimental autoimmune hepatitis (EAH) was also established and used to investigate the function of Treg-Th1-Th17-Th22 cells in disease progression. AIH patients undergoing an active state had significantly decreased numbers of CD3⁺CD4⁺CD25⁺Foxp3⁺Tregs and increased numbers of CD3⁺CD4⁺CD25^-Foxp3⁺T, CD3⁺CD4⁺IFN-γ⁺Th1, CD3⁺CD4⁺IL-17⁺Th17, and CD3⁺CD4⁺IL-2⁺Th22 cells as well as higher levels of Th1/Th17/Th22-type cytokines compared to AIH patients in remission and HC. Additionally, the numbers of CD3⁺CD4⁺CD25⁺Foxp3⁺Tregs were negatively correlated with the numbers of Th1-Th17-Th22 cells. Also, the serum levels of IL-17A and IL-22 were correlated positively with liver injury (ALT/AST), whereas the serum levels of IL-10 were correlated negatively with hypergammaglobulinaemia (IgG, IgM) in AIH patients. Interestingly, the percentages of spleen Tregs, expression of Foxp3 mRNA, and liver IL-10 levels decreased, whereas the percentages of spleen Th1-Th17-Th22 cells, expression of T-bet/AHR/RORγt mRNA, and liver IFN-γ, IL-17, and IL-22 levels increased in the murine model of EAH. Our findings demonstrated that an imbalance between Tregs and Th1-Th17-Th22 cells might contribute to the pathogenic process of AIH.

Chemokines in the cancer microenvironment and their relevance in cancer immunotherapy

The tumour microenvironment is the primary location in which tumour cells and the host immune system interact. Different immune cell subsets are recruited into the tumour microenvironment via interactions between chemokines and chemokine receptors, and these populations have distinct effects on tumour progression and therapeutic outcomes. In this Review, we focus on the main chemokines that are found in the human tumour microenvironment; we elaborate on their patterns of expression, their regulation and their roles in immune cell recruitment and in cancer and stromal cell biology, and we consider how they affect cancer immunity and tumorigenesis. We also discuss the potential of targeting chemokine networks, in combination with other immunotherapies, for the treatment of cancer.

Regulation of TH17 Cells and Associated Cytokines in Wound Healing, Tissue Regeneration, and Carcinogenesis

Wound healing is a crucial process which protects our body against permanent damage and invasive infectious agents. Upon tissue damage, inflammation is an early event which is orchestrated by a multitude of innate and adaptive immune cell subsets including TH17 cells. TH17 cells and TH17 cell associated cytokines can impact wound healing positively by clearing pathogens and modulating mucosal surfaces and epithelial cells. Injury of the gut mucosa can cause fast expansion of TH17 cells and their induction from naïve T cells through Interleukin (IL)-6, TGF-β, and IL-1β signaling. TH17 cells produce various cytokines, such as tumor necrosis factor (TNF)-α, IL-17, and IL-22, which can promote cell survival and proliferation and thus tissue regeneration in several organs including the skin, the intestine, and the liver. However, TH17 cells are also potentially pathogenic if not tightly controlled. Failure of these control mechanisms can result in chronic inflammatory conditions, such as Inflammatory Bowel Disease (IBD), and can ultimately promote carcinogenesis. Therefore, there are several mechanisms which control TH17 cells. One control mechanism is the regulation of TH17 cells via regulatory T cells and IL-10. This mechanism is especially important in the intestine to terminate immune responses and maintain homeostasis. Furthermore, TH17 cells have the potential to convert from a pro-inflammatory phenotype to an anti-inflammatory phenotype by changing their cytokine profile and acquiring IL-10 production, thereby limiting their own pathological potential. Finally, IL-22, a signature cytokine of TH17 cells, can be controlled by an endogenous soluble inhibitory receptor, Interleukin 22 binding protein (IL-22BP). During tissue injury, the production of IL-22 by TH17 cells is upregulated in order to promote tissue regeneration. To limit the regenerative program, which could promote carcinogenesis, IL-22BP is upregulated during the later phase of regeneration in order to terminate the effects of IL-22. This delicate balance secures the beneficial effects of IL-22 and prevents its potential pathogenicity. An important future goal is to understand the precise mechanisms underlying the regulation of TH17 cells during inflammation, wound healing, and carcinogenesis in order to design targeted therapies for a variety of diseases including infections, cancer, and immune mediated inflammatory disease.

Biological and pathological activities of interleukin-22

Interleukin (IL)-22, a member of the IL-10 family, is a cytokine secreted by several types of immune cells including IL-22(+)CD4(+) T cells (Th22) and IL-22 expressing innate leukocytes (ILC22). Recent studies have demonstrated that IL-22 is a key component in mucosal barrier defense, tissue repair, epithelial cell survival, and proliferation. Furthermore, accumulating evidence has defined both protective and pathogenic properties of IL-22 in a number of conditions including autoimmune disease, infection, and malignancy. In this review, we summarize the expression and signaling pathway and functional characteristics of the IL-22 and IL-22 receptor axis in physiological and pathological scenarios and discuss the potential to target IL-22 signaling to treat human diseases.