The interleukin-22/STAT3 pathway potentiates expression of inducible nitric-oxide synthase in human colon carcinoma cells

The role of IL-22 in cancer

Interleukin-22, discovered in the year of 2000, is a pleiotropic Th17 cytokine from the IL-10 family of cytokines. IL-22 signals through the type 2 cytokine receptor complex IL-22R and predominantly activates STAT3. This pathway leads to the transcription of several different types of genes, giving IL-22 context-specific functions ranging from inducing antimicrobial peptide expression to target cell proliferation. In recent years, it has been shown that IL-22 is involved in the pathogenesis of neoplasia in some cancers through its pro-proliferative and anti-apoptotic effects. This review highlights studies with recent discoveries and conclusions drawn on IL-22 and its involvement and function in various cancers. Such a study may be helpful to better understand the role of IL-22 in cancer so that new treatment could be developed targeting IL-22.

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.

A comprehensive review on RNA interference-mediated targeting of interleukins and its potential therapeutic implications in colon cancer

Colon cancer is the world's fourth leading cause of death. It is cancer of the latter part of the large intestine, i.e. the colon. Chronic inflammation over a long period also leads to the development of cancer. Cancer in the colon region is arduous to diagnose and is detected at a later stage when it metastasizes to other parts of the body like the liver, lungs, peritoneum, etc. Colon cancer is a great example of solid tumours associated with chronic inflammation. Although conventional therapies are effective, they lose their effectiveness beyond a certain point. Relapse of the disease occurs frequently. RNA interference (RNAi) is emerging as a great tool to specifically attack the cancer cells of a target site like the colon. RNAi deals with epigenetic changes made in the defective cells which ultimately leads to their death without harming the healthy cells. In this review, two types of epigenetic modulators have been considered, namely siRNA and miRNA, and their effect on interleukins. Interleukins, a class of cytokines, are major inflammatory responses of the body that are released by immune cells like leukocytes and macrophages. Some of these interleukins are pro-inflammatory, thereby promoting inflammation which eventually causes cancer. RNAi can prevent colon cancer by inhibiting pro-inflammatory interleukins.

Anxiolytic and anti-colitis effects of Moringa oleifera leaf-aqueous extract on acetic acid-induced colon inflammation in rat

Moringa oleifera decoction is believed to alleviate gastrointestinal tract diseases. This study investigated antioxidant and anxiolytic activities of its leaves aqueous extract on acetic acid-induced colitis in rats. Rats (36) were randomly divided into six groups and received (20 days) distilled water, 10 mL/kg; Moringa oleifera leaf-aqueous extract (25, 50, and 100 mg/kg) or Loperamide (5 mg/kg). On days 1, 8, 17, and 20, behavioral parameters were evaluated. Colitis was induced (day 15, except in normal group) through acetic acid (4%, 1 mL) intra-rectal administration. After sacrifice (day 21), lesion number, weight/length ratio of the colon were recorded. Oxidative stress biomarkers were evaluated. On day 20, Moringa oleifera (100 mg/kg) reduced the number of head dipping and the duration in opened arms, respectively 2.00 ± 0.37 and 5.00 ± 0.37 s against 14.50 ± 0.72 and 2.17 ± 0.48 s in the control. It decreased colon weight/length ratio: 112.29 ± 9.46 against 185.93 ± 5.28 mg/cm in the control; malondialdehyde level (P < 0.01) and nitric oxide concentration (P < 0.001), in the brain: respectively 25.60 ± 0.60 and 36.34 ± 1.19 against 34.00 ± 0.33 and 46.17 ± 3.25 µmol/mg of tissue in the control. In the serum, the extract (50 mg/kg) significantly (P < 0.05) increased the catalase activity (0.10 ± 0.00 against 0.03 ± 0.00 µmol/mg of protein in the negative control group). At 100 mg/kg, it increased (P < 0.001) reduced glutathione concentration to 5.07 ± 0.31 against 3.26 ± 0.08 µmol/mg of protein in the negative control group. The improvement on colitis pathophysiology, the antioxidant and the anxiolytic effects noted therefore suggest that Moringa oleifera can be a potential source of drugs alleviating anxiety and oxidative stress associated to ulcerative colitis.

The Role of Inflammatory Cytokines in the Pathogenesis of Colorectal Carcinoma—Recent Findings and Review

The inflammatory process plays a significant role in the development of colon cancer (CRC). Intestinal cytokine networks are critical mediators of tissue homeostasis and inflammation but also impact carcinogenesis at all stages of the disease. Recent studies suggest that inflammation is of greater importance in the serrated pathway than in the adenoma-carcinoma pathway. Interleukins have gained the most attention due to their potential role in CRC pathogenesis and promising results of clinical trials. Malignant transformation is associated with the pro-tumorigenic and anti-tumorigenic cytokines. The harmony between proinflammatory and anti-inflammatory factors is crucial to maintaining homeostasis. Immune cells in the tumor microenvironment modulate immune sensitivity and facilitate cancer escape from immune surveillance. Therefore, clarifying the role of underlying cytokine pathways and the effects of their modulation may be an important step to improve the effectiveness of cancer immunotherapy.

The Complex Network between Inflammation and Colorectal Cancer: A Systematic Review of the Literature

Simple Summary

Colorectal cancer is one of the most diffuse malignant pathologies, and many factors are involved in its genesis. Among these factors, inflammation plays an important role. Many molecules are involved in inflammation processes and are linked in different pathways, either in the sense of pro-tumorigenesis or anti-tumorigenic action. This review was conducted with the aim to review in a single paper the majority of actual knowledge in the literature and to comprehend inflammation patterns for better clinical and surgical management of patients.

Abstract

Background: colorectal cancer (CRC) has a multifactorial etiology which comprises microbiota, genetic predisposition, diet, environmental factors, and last but not least, a substantial contribution by inflammation. The aim of this study is to conduct a systematic review of the literature regarding the strong link between inflammation and colorectal cancer. Methods: A systematic review of the literature on PubMed (Medline), Scopus, Cochrane and EMBase databases was performed, following the PRISMA 2020 guidelines. Each paper was reviewed by two groups of researchers in a single-blind format by using a pre-planned Microsoft^© Excel^® grid. Results: Using automated research filters, 14,566 studies were included, but 1% was found significant by the reviewers. Seventy pathways of inflammation were described in the sequence of inflammation-carcinogenesis, and anti-tumorigenic molecules were also found. Conclusion: several studies suggest a strong role of inflammation in the tumorigenesis of colorectal cancer through different pathways: this may have a diagnostic and clinical role and also therapeutic purpose in preventing carcinogenesis by treating inflammation. In vitro tests support this theory, even if many other clinical trials are necessary. The present paper was registered in the OpenScience Framework registry (Identifier: DOI 10.17605/OSF.IO/2KG7T).

The ERK-p38MAPK-STAT3 Signalling Axis Regulates iNOS Expression and Salmonella Infection in Senescent Cells

The cellular changes occurring due to senescence like proliferation arrest, increase in free radical levels, and secretion of pro-inflammatory cytokines have been well studied, but its associated alteration in intracellular signalling networks has been scarcely explored. In this study, we examine the roles of three major kinases viz. p38 MAPK, ERK, and STAT3 in regulating iNOS expression and thereby the levels of the free radical Nitric oxide in senescent cells. Our study revealed that these kinases could differentially regulate iNOS in senescent cells compared to non-senescent cells. Further, we tested the physiological relevance of these alterations with Salmonella infection assays and established an inter-regulatory network between these kinases unique to infected senescent cells. Overall, our findings show how key signalling networks may be rewired in senescent cells rendering them phenotypically different.

Acetaminophen-Induced Liver Injury Exposes Murine IL-22 as Sex-Related Gene Product

Gaining detailed knowledge about sex-related immunoregulation remains a crucial prerequisite for the development of adequate disease models and therapeutic strategies enabling personalized medicine. Here, the key parameter of the production of cytokines mediating disease resolution was investigated. Among these cytokines, STAT3-activating interleukin (IL)-22 is principally associated with recovery from tissue injury. By investigating paradigmatic acetaminophen-induced liver injury, we demonstrated that IL-22 expression is enhanced in female mice. Increased female IL-22 was confirmed at a cellular level using murine splenocytes stimulated by lipopolysaccharide or αCD3/CD28 to model innate or adaptive immunoactivation. Interestingly, testosterone or dihydrotestosterone reduced IL-22 production by female but not by male splenocytes. Mechanistic studies on PMA/PHA-stimulated T-cell-lymphoma EL-4 cells verified the capability of testosterone/dihydrotestosterone to reduce IL-22 production. Moreover, we demonstrated by chromatin immunoprecipitation that testosterone impairs binding of the aryl hydrocarbon receptor to xenobiotic responsive elements within the murine IL-22 promoter. Overall, female mice undergoing acute liver injury and cultured female splenocytes upon inflammatory activation display increased IL-22. This observation is likely related to the immunosuppressive effects of androgens in males. The data presented concur with more pronounced immunological alertness demonstrable in females, which may relate to the sex-specific course of some immunological disorders.

Interleukin-22: a potential therapeutic target in atherosclerosis

BACKGROUND

Atherosclerosis is recognized as a chronic immuno-inflammatory disease that is characterized by the accumulation of immune cells and lipids in the vascular wall. In this review, we focus on the latest advance regarding the regulation and signaling pathways of IL-22 and highlight its impacts on atherosclerosis.

MAIN BODY

IL-22, an important member of the IL-10 family of cytokines, is released by cells of the adaptive and innate immune system and plays a key role in the development of inflammatory diseases. The binding of IL-22 to its receptor complex can trigger a diverse array of downstream signaling pathways, in particular the JAK/STAT, to induce the expression of chemokines and proinflammatory cytokines. Recently, numerous studies suggest that IL-22 is involved in the pathogenesis of atherosclerosis by regulation of VSMC proliferation and migration, angiogenesis, inflammatory response, hypertension, and cholesterol metabolism.

CONCLUSION

IL-22 promotes the development of atherosclerosis by multiple mechanisms, which may be a promising therapeutic target in the pathogenesis of atherosclerosis.

STAT3 phosphorylation is required for the HepaCAM-mediated inhibition of castration-resistant prostate cancer cell viability and metastasis

BACKGROUND

Castration-resistant prostate cancer (CRPC) is an advanced disease that is difficult to treat, the mechanism of it is unclear. This study illustrated the function of hepatocyte cell adhesion molecule (HepaCAM) on CRPC cell viability and metastasis.

METHODS

The expression of HepaCAM and p-STAT3 in CRPC tissues were determined by immunohistochemistry and western blot analysis. Cell Counting Kit-8 and colony formation assays were deployed to analyze the growth ability of CRPC cells following the adenovirus-mediated re-expression of HepaCAM. CRPC cell migration and invasion capacity were investigated by wound healing and Matrigel-coated transwell assays, respectively. The messenger RNA or protein levels of p-STAT3, CyclinD1, cMyc, MMP2, MMP9, and VEGF were determined by reverse transcription (RT) followed by quantitative real-time polymerase chain reaction (RT-qPCR), and western blot analysis after either HepaCAM re-expression alone or in combination with IL-22 treatment. A CRPC orthotopic xenograft mouse model was applied to investigate the functional effect of HepaCAM on the metastasis of CRPC cells to the lungs.

RESULTS

The expression levels of HepaCAM were decreased while those of p-STAT3 were elevated in CRPC cells compare with surrounding benign tissues (p < .001). The overexpression of HepaCAM in CRPC cells notably reduced proliferation, migration, and invasion by inhibiting the expression of p-STAT3, CyclinD1, cMyc, MMP2, MMP9, and VEGF (p < .05). In addition, the expression of HepaCAM significantly inhibited the IL-22/p-STAT3 axis and the metastasis of CRPC cells to the lungs.

CONCLUSIONS

Our data suggested that HepaCAM suppressed the viability of CRPC cells via the IL-22/p-STAT3 axis and inhibited the metastasis of CRPC cells from the prostate to the lungs (p < .05).

Features and roles of T helper 22 cells in immunological diseases and malignancies

T helper 22 (Th22) cell populations are a newly identified subset of CD4+  T cells that primarily mediate biological effects on the epithelial barrier through interleukin (IL)-22. Although, new studies showed that both Th22 and IL-22 are closely associated with the pathogenesis of inflammatory, autoimmune and allergic disease as well as malignancies. In this review, we aim to describe the development and characteristics of Th22 cells as well as their roles in the immunopathogenesis of immune-related disorders and cancer.

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 Role of Interleukins in Colorectal Cancer

Despite great progress has been made in treatment strategies, colorectal cancer (CRC) remains the predominant life-threatening malignancy with the feature of high morbidity and mortality. It has been widely acknowledged that the dysfunction of immune system, including aberrantly expressed cytokines, is strongly correlated with the pathogenesis and progression of colorectal cancer. As one of the most well-known cytokines that were discovered centuries ago, interleukins are now uncovering new insights into colorectal cancer therapy. Herein, we divide currently known interleukins into 6 families, including IL-1 family, IL-2 family, IL-6 family, IL-8 family, IL-10 family and IL-17 family. In addition, we comprehensively reviewed the oncogenic or antitumour function of each interleukin involved in CRC pathogenesis and progression by elucidating the underlying mechanisms. Furthermore, by providing interleukins-associated clinical trials, we have further driven the profound prospect of interleukins in the treatment of colorectal cancer.

Role of gut microbiota-immunity axis in patients undergoing surgery for colorectal cancer: Focus on short and long-term outcomes

Human body is colonized by a huge amount of microorganisms mostly located in the gastrointestinal tract. These dynamic communities, the environment and their metabolites constitute the microbiota. Growing data suggests a causal role of a dysbiotic microbiota in several pathologies, such as metabolic and neurological disorders, immunity dysregulations and cancer, especially the well-studied colorectal cancer development. However, many were preclinical studies and a complete knowledge of the pathogenetic mechanisms in humans is still absent. The gut microbiota can exert direct or indirect effects in different phases of colorectal cancer genesis. For example, Fusobacterium nucleatum promotes cancer through cellular proliferation and some strains of Escherichia coli and Bacteroides fragilis produce genotoxins. However, dysbiosis may also cause a pro-inflammatory state and the stimulation of a Th17 response with IL-17 and IL-22 secretion that have a pro-oncogenic activity, as demonstrated for Fusobacterium nucleatum. Microbiota has a crucial role in several stages of postoperative course; dysbiosis in fact seems related with surgical site infections and Enterococcus faecalis (and other collagenase-producers microbes) are suggested as a cause of anastomotic leak. Consequently, unbalanced presence of some species, together with altered immune response may also have a prognostic role. Microbiota has also a substantial role in effectiveness of chemotherapy, chemoresistance and in the related side effects. In other words, a complete knowledge of the fine pathological mechanisms of gut microbiota may provide a wide range of new diagnostic tools other than therapeutic targets in the light of tailored medicine.

Molecular signature of interleukin-22 in colon carcinoma cells and organoid models

Interleukin (IL)-22 activates STAT (signal transducer and activator of transcription) 3 and antiapoptotic and proproliferative pathways; but beyond this, the molecular mechanisms by which IL-22 promotes carcinogenesis are poorly understood. Characterizing the molecular signature of IL-22 in human DLD-1 colon carcinoma cells, we observed increased expression of 26 genes, including NNMT (nicotinamide N-methyltransferase, ≤10-fold) and CEA (carcinoembryonic antigen, ≤7-fold), both known to promote intestinal carcinogenesis. ERP27 (endoplasmic reticulum protein-27, function unknown, ≤5-fold) and the proinflammatory ICAM1 (intercellular adhesion molecule-1, ≤4-fold) were also increased. The effect on CEA was partly STAT3-mediated, as STAT3-silencing reduced IL-22-induced CEA by ≤56%. Silencing of CEA or NNMT inhibited IL-22-induced proliferation/migration of DLD-1, Caco-2, and SW480 colon carcinoma cells. To validate these results in primary tissues, we assessed IL-22-induced gene expression in organoids from human healthy colon and colon cancer patients, and from normal mouse small intestine and colon. Gene regulation by IL-22 was similar in DLD-1 cells and human and mouse healthy organoids. CEA was an exception with no induction by IL-22 in organoids, indicating the 3-dimensional organization of the tissue may produce signals absent in 2D cell culture. Importantly, augmentation of NNMT was 5-14-fold greater in human cancerous compared to normal organoids, supporting a role for NNMT in IL-22-mediated colon carcinogenesis. Thus, NNMT and CEA emerge as mediators of the tumor-promoting effects of IL-22 in the intestine. These data advance our understanding of the multifaceted role of IL-22 in the gut and suggest the IL-22 pathway may represent a therapeutic target in colon cancer.

IL-18/IL-18BP and IL-22/IL-22BP: Two interrelated couples with therapeutic potential

Interleukin (IL)-18 and IL-22 are key components of cytokine networks that play a decisive role in (pathological) inflammation, host defense, and tissue regeneration. Tight regulation of cytokine-driven signaling, inflammation, and immunoactivation is supposed to enable nullification of a given deleterious trigger without mediating overwhelming collateral tissue damage or even activating a cancerous face of regeneration. In fact, feedback regulation by specific cytokine opponents is regarded as a major means by which the immune system is kept in balance. Herein, we shine a light on the interplay between IL-18 and IL-22 and their opponents IL-18 binding protein (IL-18BP) and IL-22BP in order to provide integrated information on their biology, pathophysiological significance, and prospect as targets and/or instruments of therapeutic intervention.

Citrobacter rodentium induces rapid and unique metabolic and inflammatory responses in mice suffering from severe disease

The mouse pathogen Citrobacter rodentium is used to model infections with enterohaemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC). Pathogenesis is commonly modelled in mice developing mild disease (e.g., C57BL/6). However, little is known about host responses in mice exhibiting severe colitis (e.g., C3H/HeN), which arguably provide a more clinically relevant model for human paediatric enteric infection. Infection of C3H/HeN mice with C. rodentium results in rapid colonic colonisation, coinciding with induction of key inflammatory signatures and colonic crypt hyperplasia. Infection also induces dramatic changes to bioenergetics in intestinal epithelial cells, with transition from oxidative phosphorylation (OXPHOS) to aerobic glycolysis and higher abundance of SGLT4, LDHA, and MCT4. Concomitantly, mitochondrial proteins involved in the TCA cycle and OXPHOS were in lower abundance. Similar to observations in C57BL/6 mice, we detected simultaneous activation of cholesterol biogenesis, import, and efflux. Distinctly, however, the pattern recognition receptors NLRP3 and ALPK1 were specifically induced in C3H/HeN. Using cell‐based assays revealed that C. rodentium activates the ALPK1/TIFA axis, which is dependent on the ADP‐heptose biosynthesis pathway but independent of the Type III secretion system. This study reveals for the first time the unfolding intestinal epithelial cells' responses during severe infectious colitis, which resemble EPEC human infections.

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.

The Role of Adaptor Protein CARD9 in Colitis-Associated Cancer

The adaptor protein CARD9 plays an important role in anti-fungal immunity responses, linking detection of fungi by surface receptors to activation of the transcription factor nuclear factor κB (NF-κB). Recent studies indicate that CARD9 also plays different but vital roles during the development of colitis-associated colorectal cancer (CAC). This review summarizes the current understanding of CARD9 functions in CAC, and we discuss its potentially carcinogenic mechanisms.

Gut Microbiota and IL-17A: Physiological and Pathological Responses

IL-17A is a cytokine which is produced by several immune and non-immune cells. The cytokine plays dual roles from protection from microbes and protection from pro-inflammatory based diseases to induction of the pro-inflammatory based diseases. The main mechanisms which lead to the controversial roles of IL-17A are yet to be clarified. Gut microbiota (GM) are the resident probiotic bacteria in the gastrointestinal tracts which have been introduced as a plausible regulator of IL-17A production and functions. This review article describes the recent information regarding the roles played by GM in determination of IL-17A functions outcome.

Inflammatory monocytes provide a niche for Salmonella expansion in the lumen of the inflamed intestine

Salmonella exploit host-derived nitrate for growth in the lumen of the inflamed intestine. The generation of host-derived nitrate is dependent on Nos2, which encodes inducible nitric oxide synthase (iNOS), an enzyme that catalyzes nitric oxide (NO) production. However, the cellular sources of iNOS and, therefore, NO-derived nitrate used by Salmonella for growth in the lumen of the inflamed intestine remain unidentified. Here, we show that iNOS-producing inflammatory monocytes infiltrate ceca of mice infected with Salmonella. In addition, we show that inactivation of type-three secretion system (T3SS)-1 and T3SS-2 renders Salmonella unable to induce CC- chemokine receptor-2- and CC-chemokine ligand-2-dependent inflammatory monocyte recruitment. Furthermore, we show that the severity of the pathology of Salmonella- induced colitis as well as the nitrate-dependent growth of Salmonella in the lumen of the inflamed intestine are reduced in mice that lack Ccr2 and, therefore, inflammatory monocytes in the tissues. Thus, inflammatory monocytes provide a niche for Salmonella expansion in the lumen of the inflamed intestine.

Salmonella exploit gut inflammation to edge out competing microbes in the intestinal lumen and establish infection. Notably, Salmonella use inflammation-derived nitrate for growth in the intestinal lumen. The generation of inflammation-derived nitrate is dependent on Nos2, which encodes inducible nitric oxide synthase (iNOS), an enzyme that catalyzes nitric oxide production. However, the cellular sources of iNOS and, therefore, the nitric oxide-derived nitrate used by Salmonella for growth in the inflamed intestine remain unidentified, presenting an important, long-standing open question. Here, we show that iNOS-producing inflammatory monocytes, which are phagocyte precursors that play a critical role in immunity and host defense, promote nitrate-dependent Salmonella expansion in the inflamed intestine, providing new insights into how Salmonella exploit gut inflammation to establish infection.

The connection between the Th17 cell related cytokines and cancer stem cells in cancer: Novel therapeutic targets

Cancer Stem Cells (CSCs) are the subpopulation of cells present in the different types of cancers with capabilities of self-renewal, differentiation, and tumorigenicity when transplanted into an animal host. The research work on the CSC has been providing a promising approach for the improvement of cancer therapies in the future. The CSCs have a close connection with the cytokines related with the T helper 17 (Th17) cell and other factors present in the tumor microenvironment, and these play a pivotal role in tumor progression and metastasis. The properties of CSCs are well defined in various type of tumor which is mainly developed by chemically and spontaneously in murine cancer model but in human defined primarily on acute myeloid leukemia, glioma, and breast cancer. The role of Th1, Th2, Natural Killer cells are well described in the cancer biology, but the Th17 cells are the subset which is recently exploited, and lots of research are going on. In this Review, we summarize current findings of the characteristics and functions of the Th17 cell and its signature cytokines in different cancers and their interconnections with cancer stem cells and with their markers. We have also discussed the functional properties of CSCs and how the CSCs markers can be distinguished from normal stem cells markers. We have also talked about the strategies that are efficiently targeting of CSCs and Th17 cells in different cancers.

Intestinal Epithelial Cells and the Microbiome Undergo Swift Reprogramming at the Inception of Colonic Citrobacter rodentium Infection

The mouse pathogen C. rodentium is a widely used model for colonic infection and has been a major tool in fundamental discoveries in the fields of bacterial pathogenesis and mucosal immunology. Despite extensive studies probing acute C. rodentium infection, our understanding of the early stages preceding the infection climax remains relatively undetailed. To this end, we apply a multiomics approach to resolve temporal changes to the host and microbiome during early infection. Unexpectedly, we found immediate and dramatic responses occurring on the day of colonic infection, both in the host intestinal epithelial cells and in the microbiome. Our study suggests changes in cholesterol and carbon metabolism in epithelial cells are instantly induced upon pathogen detection in the colon, corresponding with a shift to primarily facultative anaerobes constituting the microbiome. This study contributes to our knowledge of disease pathogenesis and mechanisms of barrier regulation, which is required for development of novel therapeutics targeting the intestinal epithelium.

We used the mouse attaching and effacing (A/E) pathogen Citrobacter rodentium, which models the human A/E pathogens enteropathogenic Escherichia coli and enterohemorrhagic E. coli (EPEC and EHEC), to temporally resolve intestinal epithelial cell (IEC) responses and changes to the microbiome during in vivo infection. We found the host to be unresponsive during the first 3 days postinfection (DPI), when C. rodentium resides in the caecum. In contrast, at 4 DPI, the day of colonic colonization, despite only sporadic adhesion to the apex of the crypt, we observed robust upregulation of cell cycle and DNA repair processes, which were associated with expansion of the crypt Ki67-positive replicative zone, and downregulation of multiple metabolic processes (including the tricarboxylic acid [TCA] cycle and oxidative phosphorylation). Moreover, we observed dramatic depletion of goblet and deep crypt secretory cells and an atypical regulation of cholesterol homeostasis in IECs during early infection, with simultaneous upregulation of cholesterol biogenesis (e.g., 3-hydroxy-3-methylglutaryl–coenzyme A reductase [Hmgcr]), import (e.g., low-density lipoprotein receptor [Ldlr]), and efflux (e.g., AbcA1). We also detected interleukin 22 (IL-22) responses in IECs (e.g., Reg3γ) on the day of colonic colonization, which occurred concomitantly with a bloom of commensal Enterobacteriaceae on the mucosal surface. These results unravel a new paradigm in host-pathogen-microbiome interactions, showing for the first time that sensing a small number of pathogenic bacteria triggers swift intrinsic changes to the IEC composition and function, in tandem with significant changes to the mucosa-associated microbiome, which parallel innate immune responses.

Centipedegrass extracts regulate LPS-mediated aberrant immune responses by inhibiting Janus kinase

BACKGROUND

Centipedegrass extract (CGE) is rich in several polyphenolic compounds including C-glycosylflavonoids, such as maysin and its derivatives, and exerts antioxidant, anti-adipogenic and anticancer effects. However, the effect of CGE on the immune system is unclear.

PURPOSE

CGE might inhibit NO production induced by lipopolysaccharide (LPS). In this study, we propose a molecular mechanism for regulation of aberrant immune responses by CGE in LPS-stimulated RAW264.7 cells.

STUDY DESIGN

We will preparation of Centipedegrass extract and purify partially in rich of maysin and its derivatives. And examine the effect of the CGE on immune system using LPS-induced RAW cells and animals.

METHODS

LPS-induced nitric oxide (NO) and interleukin-6 levels were measured by enzyme-linked immunosorbent assay. The mRNA and protein levels of immune mediators were analyzed by reverse-transcription polymerase chain reaction and immunoblotting, respectively.

RESULTS

CGE inhibited LPS-induced NO production in a concentration-dependent manner by suppressing inducible nitric oxide synthase (iNOS) expression in LPS-stimulated cells; this effect was mediated by inhibition of the JAK/STAT pathway. However, CGE did not regulate the expression of other factors, including phosphorylated p38, c-jun N-terminal kinase, or extracellular signal-regulated kinase 1/2. In addition, CGE increased T cells percentage in peripheral blood after oral administration.

CONCLUSION

These results indicate that CGE suppresses LPS-induced production of NO and expression of iNOS by directly inhibiting JAK2 kinase activity and enhancing effects on the immune system in mice.

IL-22: An Underestimated Player in Natural Resistance to Tuberculosis?

Approximately 10% of individuals latently infected with Mycobacterium tuberculosis (Mtb) develop active tuberculosis (TB) during their lifetime. Although it is well recognized that T-helper 1 immune responses are crucial for containing latent TB infection, the full array of host factors conferring protective immunity from TB progression are not completely understood. IL-22 is produced by cells of the innate and adaptive immune system including innate lymphoid cells, and natural killer cells as well as T lymphocytes (Th1, Th17, and Th22) and binds to its cognate receptor, the IL-22R1, which is expressed on non-hematopoietic cells such as lung epithelial cells. However, recent studies suggest that Mtb induces expression of the IL-22R1 on infected macrophages and multiple studies have indicated a protective role of IL-22 in respiratory tract infections. Reduced concentrations of circulating IL-22 in active TB compared to latent TB and decreased percentages of Mtb-specific IL-22 producing T cells in TB patients compared to controls designate this cytokine as a key player in TB immunology. More recently, it has been shown that in type 2 diabetes (T2D) and TB co-morbidity serum IL-22 concentrations are further reduced compared to TB patients without co-morbidities. However, whether a causative link between low IL-22 and increased susceptibility to TB and disease severity of TB exists remains to be established. This review summarizes the contribution of IL-22, a potentially under-appreciated key player in natural resistance to TB, at the interface between the immune response to Mtb and the lung epithelium.

Amelioration of UVB-induced oxidative stress and inflammation in fat-1 transgenic mouse skin

ω-3 polyunsaturated fatty acids (PUFAs), which are abundant in fish oils, are known to scavenge lipid peroxyl radicals and potentiate host immune defence. As UVB-induced oxidative stress and inflammation have been implicated in apoptotic cell death, this study was aimed to investigate the anti-inflammatory, anti-oxidative, and anti-apoptotic capacity of fat-1 transgenic mice capable of converting ω-6 to ω-3 PUFAs. Wild-type (WT) C57BL/6 mice and fat-1 mice were maintained on the AIN-93 diet supplemented with 10% safflower oil rich in ω-6 PUFAs for 5 weeks. The ω-3/ω-6 PUFA ratio was significantly higher in the dorsal skin of fat-1 mice than that in the WT mice. Upon single exposure to UVB (5.0 kJ/m²) radiation, fat-1 mice showed inflammatory as well as oxidative tissue damage and the expression of pro-inflammatory enzymes, cyclooxygenases-2 and inducible nitric oxide synthase in the skin to a much lesser extent than the WT mice. The protection of fat-1 mice from UVB-induced skin inflammation was associated with decreased phosphorylation of STAT3. Moreover, UVB-induced apoptosis was attenuated in fat-1 mouse skin. In comparison to WT animals, higher levels of Nrf2 and its target proteins, such as heme oxygenase-1, NAD(P)H:quinone oxidoreductase-1 and thioredoxin-1, were found in the skin of fat-1 mice.

Influence of corticosteroid therapy on IL-18 and nitric oxide production during Behçet's disease

BACKGROUND AND AIMS

Behçet's disease (BD) is a chronic multisystemic inflammatory disease with complex etiopathogenesis. Th1-proinflammatory cytokines seem to be involved in its pathogenesis. Our current study aims to evaluate interleukin-18 (IL-18) and nitric oxide (NO) involvement in the development of different clinical manifestations of BD as well as to investigate the corticosteroid therapy effect on this production in Algerian patients.

METHODS

For this purpose, we evaluated in vivo and ex vivo IL-18, interferon-γ (IFN-γ) levels using ELISA and NO production by the Griess' method in naïve-active and corticosteroid-treated BD patients with different clinical manifestations. Additionally, we assessed CD40/CD40L expression by flow cytometrics assay in these groups of patients.

RESULTS AND DISCUSSION

Our results indicate that IL-18 and nitrite levels were higher in naïve-active BD patients. Interestingly, this high production differed according to the clinical manifestations and was associated with an increased risk of mucocutaneous and vascular involvement. Concerning corticosteroid treated-active BD patients, no difference was observed in this production between each clinical subgroup. However, IFN-γ levels increased in all categories of active patients. Interestingly, corticosteroid therapy reduced significantly these inflammatory mediators regardless of the clinical manifestations studied. In addition, the CD40/CD40L expression differed according to the clinical presentations.

CONCLUSION

Collectively, our results suggest that concomitant high production of IL-18 and NO in naïve-active BD patients is related to an increased risk of mucocutaneous lesions and vascular involvement. Moreover, the relationship between these two inflammatory markers could constitute a predictable tool of BD clinical presentations and an early factor of therapy efficiency.

Ex vivo immunomodulatory effect of ethanolic extract of propolis during Celiac Disease: involvement of nitric oxide pathway

Celiac Disease (CeD) is a chronic immune-mediated enteropathy, in which dietary gluten induces an inflammatory reaction, predominantly in the duodenum. Propolis is a resinous hive product, collected by honeybees from various plant sources. Propolis is well-known for its anti-inflammatory, anti-oxidant and immunomodulatory effects, due to its major compounds, polyphenols and flavonoids. The aim of our study was to assess the ex vivo effect of ethanolic extract of propolis (EEP) upon the activity and expression of iNOS, along with IFN-γ and IL-10 production in Algerian Celiac patients. In this context, PBMCs isolated from peripheral blood of Celiac patients and healthy controls were cultured with different concentrations of EEP. NO production was measured using the Griess method, whereas quantitation of IFN-γ and IL-10 levels was performed by ELISA. Inducible nitric oxide synthase (iNOS) expression, NFκB and pSTAT-3 activity were analyzed by immunofluorescence assay. Our results showed that PBMCs from Celiac patients produced high levels of NO and IFN-γ compared with healthy controls (HC). Interestingly, EEP reduced significantly, NO and IFN-γ levels and significantly increased IL-10 levels at a concentration of 50 µg/mL. Importantly, EEP downmodulated the iNOS expression as well as the activity of NFκB and pSTAT-3 transcription factors. Altogether, our results highlight the immunomodulatory effect of propolis on NO pathway and on pro-inflammatory cytokines. Therefore, we suggest that propolis may constitute a potential candidate to modulate inflammation during Celiac Disease and has a potential therapeutic value.

A catch-22: Interleukin-22 and cancer

Barrier surfaces of multicellular organisms are in constant contact with the environment and infractions to the integrity of epithelial surfaces is likely a frequent event. Interestingly, components of the immune system, that can be activated by environmental compounds such as the microbiota or nutrients, are interspersed among epithelial cells or directly underlie the epithelium. It is now appreciated that immune cells continuously receive and integrate signals from the environment. Curiously, such continuous reception of stimulation does not normally trigger an inflammatory response but mediators produced by immune cells in response to such signals seem to rather promote barrier integrity and repair. The molecular mediators involved in this process are poorly understood. In recent years, the cytokine interleukin-22, produced mainly by group 3 innate lymphoid cells (ILCs), has been studied as a paradigm for how immune cells can control various aspects of epithelial cell function because expression of its receptor is restricted to non-hematopoietic cells. We will summarize here the diverse roles of IL-22 for the malignant transformation of epithelial cells, for tumor growth, wound healing and tissue repair. Furthermore, we will discuss IL-22 as a potential therapeutic target.

STAT3 promotes IFNγ/TNFα-induced muscle wasting in an NF-κB-dependent and IL-6-independent manner

Cachexia is a debilitating syndrome characterized by involuntary muscle wasting that is triggered at the late stage of many cancers. While the multifactorial nature of this syndrome and the implication of cytokines such as IL‐6, IFNγ, and TNFα is well established, we still do not know how various effector pathways collaborate together to trigger muscle atrophy. Here, we show that IFNγ/TNFα promotes the phosphorylation of STAT3 on Y705 residue in the cytoplasm of muscle fibers by activating JAK kinases. Unexpectedly, this effect occurs both in vitro and in vivo independently of IL‐6, which is considered as one of the main triggers of STAT3‐mediated muscle wasting. pY‐STAT3 forms a complex with NF‐κB that is rapidly imported to the nucleus where it is recruited to the promoter of the iNos gene to activate the iNOS/NO pathway, a well‐known downstream effector of IFNγ/TNFα‐induced muscle loss. Together, these findings show that STAT3 and NF‐κB respond to the same upstream signal and cooperate to promote the expression of pro‐cachectic genes, the identification of which could provide effective targets to combat this deadly syndrome.

Interleukin-22 drives nitric oxide-dependent DNA damage and dysplasia in a murine model of colitis-associated cancer

The risk of colon cancer is increased in patients with Crohn's disease and ulcerative colitis. Inflammation-induced DNA damage could be an important link between inflammation and cancer, although the pathways that link inflammation and DNA damage are incompletely defined. RAG2-deficient mice infected with Helicobacter hepaticus (Hh) develop colitis that progresses to lower bowel cancer. This process depends on nitric oxide (NO), a molecule with known mutagenic potential. We have previously hypothesized that production of NO by macrophages could be essential for Hh-driven carcinogenesis, however, whether Hh infection induces DNA damage in this model and whether this depends on NO has not been determined. Here we demonstrate that Hh infection of RAG2-deficient mice rapidly induces expression of iNOS and the development of DNA double-stranded breaks (DSBs) specifically in proliferating crypt epithelial cells. Generation of DSBs depended on iNOS activity, and further, induction of iNOS, the generation of DSBs, and the subsequent development of dysplasia were inhibited by depletion of the Hh-induced cytokine IL-22. These results demonstrate a strong association between Hh-induced DNA damage and the development of dysplasia, and further suggest that IL-22-dependent induction of iNOS within crypt epithelial cells rather than macrophages is a driving force in this process.

Response of iNOS and its relationship with IL-22 and STAT3 in macrophage activity in the polar forms of leprosy

Leprosy is a chronic granulomatous infection that manifests as different clinical forms related to the immunological response. The aim of the study was to evaluated the response of IL-22, STAT3, CD68 and iNOS in leprosy skin lesions. The mean number IL-22 positive cells was 12.12±1.90cells/field in the TT form and 31.31±2.91cells/field in the LL form. STAT3 positive cells was 5.29±1.96 cells/field in the TT form, while this number was 11.13±3.48cells/field in the LL form. The mean number of CD68 positive cells was 25.18±6.21cells/field in the TT form and 62.81±8.13cells/field in the LL form. Quantitative analysis of iNOS revealed a significant difference, with the mean number of cells expressing the enzyme being 30.24±2.88cells/field in the TT form compared to 35.44±4.69cells/field in the LL form. Linear correlations in lesions of TT patients showed a moderate positive correlations between CD68 and iNOS, STAT3 and Inos, IL-22 and STAT3, and IL-22 and iNOS. Our results demonstrate that these factors can act synergistically to induce a microbicidal activity in the population of macrophages in the leprosy lesions.

Hypothermia Promotes Interleukin-22 Expression and Fine-Tunes Its Biological Activity

Disturbed homeostasis as a result of tissue stress can provoke leukocyte responses enabling recovery. Since mild hypothermia displays specific clinically relevant tissue-protective properties and interleukin (IL)-22 promotes healing at host/environment interfaces, effects of lowered ambient temperature on IL-22 were studied. We demonstrate that a 5-h exposure of endotoxemic mice to 4°C reduces body temperature by 5.0° and enhances splenic and colonic il22 gene expression. In contrast, tumor necrosis factor-α and IL-17A were not increased. In vivo data on IL-22 were corroborated using murine splenocytes and human peripheral blood mononuclear cells (PBMC) cultured upon 33°C and polyclonal T cell activation. Upregulation by mild hypothermia of largely T-cell-derived IL-22 in PBMC required monocytes and associated with enhanced nuclear T-cell nuclear factor of activated T cells (NFAT)-c2. Notably, NFAT antagonism by cyclosporin A or FK506 impaired IL-22 upregulation at normothermia and entirely prevented its enhanced expression upon hypothermic culture conditions. Data suggest that intact NFAT signaling is required for efficient IL-22 induction upon normothermic and hypothermic conditions. Hypothermia furthermore boosted early signal transducer and activator of transcription 3 activation by IL-22 and shaped downstream gene expression in epithelial-like cells. Altogether, data indicate that hypothermia supports and fine-tunes IL-22 production/action, which may contribute to regulatory properties of low ambient temperature.

Interleukin-22 and Cyclosporine in Aggressive Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinomas (SCCs) account for up to 10,000 deaths annually in the United States. Most of the more than 700,000 SCCs diagnosed are cured by excision with clear margins; however, metastasis can occur despite seemingly adequate treatment in some cases. Immune-suppressed organ transplant recipients are 60 to 100 times more likely to develop SCC than immune-competent individuals. Transplant-associated SCCs occur more frequently and behave more aggressively, showing higher risk of recurrence and metastasis. This article identifies a potential role for interleukin-22 in driving SCC proliferation, particularly in solid organ transplant recipients taking cyclosporine.

Increased frequency of circulating Th22 cells in patients with B-cell non-Hodgkin's lymphoma

T helper (Th) 22 cells play important roles in the pathogenesis of autoimmune and inflammatory diseases, and their function in tumors remains uncertain. In the current study, we investigated the alternations and clinical significance of circulating Th22 cells in patients with B-cell non-Hodgkin's lymphoma (B-NHL). We found that the frequency of Th22 cells was significantly elevated in peripheral blood of newly-diagnosed B-NHL patients, and returned to normal level after chemotherapy. In consistent with increased Th22 frequency, plasma IL-22 and IL-6 levels in B-NHL patients were remarkably increased. Moreover, the increased Th22 frequency was associated with the older age (> 60 yr) and a poorer response to therapy in B-NHL patients. In addition, there existed a statistically positive correlation between circulating Th22 and Th17 frequencies in B-NHL patients. Our data demonstrated that circulating Th22 frequency was associated with the clinical outcome and prognosis of B-NHL patients, indicating that Th22 immune response might play an important role in the development and progression of B-NHL.

The interplay between the microbiome and the adaptive immune response in cancer development

The data from different studies suggest a bacterial role in cancer genesis/progression, often modulating the local immune response. This is particularly so at the mucosal level where the bacterial presence is strong and the immune system is highly reactive. The epithelial surfaces of the body, such as the skin and mucosa, are colonized by a vast number of microorganisms, which represent the so-called normal microbiome. Normally the microbiome does not cause a proinflammatory response because the immune system has developed different strategies for the tolerance of commensal bacteria, but when these mechanisms are impaired or new pathogenic bacteria are introduced into this balanced system, the immune system reacts to the microbiome and can trigger tumor growth in the intestine. In this review, we discuss the potential role of the bacterial microbiome in carcinogenesis, focusing on the direct and indirect immune adaptive mechanisms, that the bacteria can modulate in different ways.

Cyclosporine A immunosuppression drives catastrophic squamous cell carcinoma through IL-22

Immune-suppressed organ transplant recipients (OTRs) can develop catastrophic squamous cell carcinoma (SCC), characterized by multiple primary tumors, extensive body surface area involvement, or metastases. There are currently no curative systemic therapies available. We previously showed that IL-22 enhances SCC proliferation. Herein, we examined links between cyclosporine (CSA), IL-22, and SCC in patients, cell lines, and mice with UV light-induced SCC. Eighteen of 114 OTRs developed catastrophic SCC, which was strongly associated with CSA treatment. We found that CSA drives T cell polarization toward IL-22-producing T22 cells, and CSA treatment increased IL-22 receptor in SCC cells. SCC tissue from OTRs showed increased expression of IL-22RA1. CSA potentiated rescue by IL-22 of serum-starved SCC cells; treatment of SCC cells with IL-22 and CSA increased both their migratory and invasive capacity. In a UV-induced model of SCC in SKH-1 immunocompetent mice, treatment with anti-IL-22 antibody reduced tumor number and tumor burden. We found that catastrophic SCC in OTRs is associated with CSA use, which may be acting by favoring T22 polarization. Since anti-IL-22 antibody administration decreased tumor number and tumor burden in vivo, blockade of the IL-22 axis may be developed as a viable therapeutic option for catastrophic SCC.

Mechanisms of Cholera Toxin in the Modulation of TH17 Responses

Numerous studies have shown that TH17 cells and their signature cytokine IL-17A are critical to host defense against various bacterial and fungal infections. The protective responses mediated by TH17 cells and IL-17A include the recruitment of neutrophils, release of antimicrobial peptides and chemokines, and enhanced tight junction of epithelial cells. Due to the importance of TH17 cells in infections, efforts have been made to develop TH17-based vaccines. The goal of vaccination is to establish a protective immunological memory. Most currently approved vaccines are antibody-based and have limited protection against stereotypically different strains. Studies show that T-cell-based vaccines may overcome this limitation and protect hosts against infection of different strains. Two main strategies are used to develop TH17 vaccines: identification of TH17-specific antigens and TH17-skewing adjuvants. Studies have revealed that cholera toxin (CT) induces a potent Th17 response following vaccination. Antigen vaccination along with CT induces a robust TH17 response, which is sometimes accompanied by TH1 responses. Due to the toxicity of CT, it is hard to apply CT in a clinical setting. Thus, understanding how CT modulates TH17 responses may lead to the development of successful TH17-based vaccines.

Innate lymphoid cells involve in tumorigenesis

Innate lymphoid cells (ILCs) promptly initiate cytokine responses to pathogen exposure in the mucosa and mucosal-associated lymphoid tissues. ILCs were recently categorized as being of the lymphoid lineage and have been classified into three groups. ILCs play important roles in immunity against pathogens, and an anti-tumor immune-related function was recently demonstrated. In this review we discuss whether and how ILCs involve in the tumorigenesis, providing new insights into the mechanisms underlying the particular functions of ILCs as well as the potential targets for tumor intervention.

Clinical Implications of Hepatocyte Growth Factor, Interleukin-20, and Interleukin-22 in Serum and Bronchoalveolar Fluid of Patients with Non-Small Cell Lung Cancer

Hepatocyte growth factor (HGF) is involved in tumorigenesis, interleukin-20 (IL-20) is an inhibitor of angiogenesis, and interleukin-22 (IL-22) stimulates tumor growth. The aim of this study was to determine the level of HGF, IL-20, and IL-22 in both serum and bronchoalveolar lavage fluid (BALF) of non-small cell lung cancer (NSCLC) patients before onset of chemotherapy, the nature of the interrelationships between these markers, and their prognostic significance regarding post-chemotherapy survival time. We studied 46 NSCLC patients and 15 healthy subjects as a control group. We found significantly higher serum levels of HGF and IL-22 in the NSCLC patients than those in controls [pg/ml: HGF - 1911 (693-6510) vs. 1333 (838-3667), p = 0.0004; IL-22 - 10.66 (1.44-70.34) vs. 4.69 (0.35-12.29), p = 0.0007]. In contrast, concentrations of HGF and IL-22 in BALF were lower in NSCLC patients than those in controls [pg/ml: HGF - 72 (6-561) vs. 488 (14-2003), p = 0.0002; IL-22 - 2.28 (0.70-6.52) vs. 3.72 (2.76-5.64), p = 0.002]. In the NSCLC patients, there was a negative correlation between the serum level of IL-20 and time to tumor progression (r = -0.405, p = 0.04) and between the serum level of HGF and survival time (r = -0.41, p = 0.005). In addition, a higher serum level of HGF and a higher BALF level of IL-22 in patients were linked with a shorter overall survival. We conclude that HGF, IL-20, and IL-22 in the serum and BALF of NSCLC patients before chemotherapy may be a prognostic of cancer progression.

Coccomyxa Gloeobotrydiformis Improves Learning and Memory in Intrinsic Aging Rats

Declining in learning and memory is one of the most common and prominent problems during the aging process. Neurotransmitter changes, oxidative stress, mitochondrial dysfunction and abnormal signal transduction were considered to participate in this process. In the present study, we examined the effects of Coccomyxa gloeobotrydiformis (CGD) on learning and memory ability of intrinsic aging rats. As a result, CGD treated (50 mg/kg·d or 100 mg/kg ·d for a duration of 8 weeks) 22-month-old male rats, which have shown significant improvement on learning and spatial memory ability compared with control, which was evidently revealed in both the hidden platform tasks and probe trials. The following immunohistochemistry and Western blot experiments suggested that CGD could increase the content of Ach and thereby improve the function of the cholinergic neurons in the hippocampus, and therefore also improving learning and memory ability of the aged rats by acting as an anti-inflammatory agent. The effects of CGD on learning and memory might also have an association with the ERK/CREB signalling. The results above suggest that the naturally made drug CGD may have several great benefit as a multi-target drug in the process of prevention and/or treatment of age-dependent cognitive decline and aging process.

Clinical significance of interleukin-22 in multiple myeloma

OBJECTIVE

Interleukin-22 (IL-22) is a cytokine participating in many aspects of inflammation. Multiple myeloma (MM) is a malignant disease of plasma cells with characteristic immune deregulation. We estimated serum levels of IL-22 in MM patients, both in activity and remission, in order to apprehend its possible participation in MM biology.

METHODS

We measured serum levels of IL-22 along with beta-2 microglobulin (B2M), paraprotein, and interleukin-1beta (IL-1beta), as well as degree of bone marrow infiltration, in 51 patients with active MM and in 22 of them in remission.

RESULTS

We found that IL-22 was higher in active MM patients, compared to both controls and patients in remission, and also in patients in remission compared to controls. Moreover, IL-22 was increasing in parallel with the disease stage and also correlated with B2M, IL1-beta, and degree of infiltration.

DISCUSSION

We suggest that the elevated levels of IL-22 in active MM patients, in parallel with disease activity, and in positive correlation with IL-1beta, may represent the inflammatory element of the disease. This increased occurrence of IL-22 may enhance myeloma proliferation and growth, and moreover, may participate in the mechanisms of immune deregulation.

Effect of IL-22 on expression of intestinal trefoil factor in intestinal epithelial cells

AIM: To investigate the effect of interleukin-22 (IL-22) on the intestinal trefoil factor (ITF/TFF3) expression in IEC-6 cells and discuss the possible mechanism.

METHODS: IEC-6 cells were treated with IL-22 at different concentrations (1, 10, or 100 ng/mL) for 12, 24, or 48 h. The mRNA expression of TFF3, signal transducer and activator of transcription 3 (STAT3), STAT6 and nuclear factor-κB (NF-κB) in IEC-6 cells was measured by RT-PCR.

RESULTS: The mRNA expression of TFF3 and STAT3 in IEC-6 cells treated with 1 ng/mL IL-22 was not significantly up-regulated when incubated for 0, 12, 24 or 48 h (P > 0.05). With time increasing, the mRNA expression of TFF3 in IEC-6 cells treated with 10 ng/mL IL-22 increased and the comparison between any two time points of 0, 12, 24 and 48 h showed significant differences (P < 0.05) except the comparison between the time points of 12 and 24 h; the mRNA expression of STAT3 also increased, and there were significant differences in any two time points (P < 0.05), except between 0 and 12 h (P > 0.05). When treated with 100 ng/mL IL-22, the mRNA expression of TFF3 in IEC-6 cells showed obvious up-regulation with time increasing, and the comparison between any two time points was statistically different (P < 0.05); the relationship between the mRNA expression of STAT3 and treatment time was the same as the group of 10 ng/mL. When IEC-6 cells were treated for 12 h, the mRNA expression of TFF3 was significantly higher in the 100 ng/mL group compared with the 1 ng/mL and 10 ng/mL groups (P < 0.05), although there was no statistical difference between the groups of 1 ng/mL and 10 ng/mL; the mRNA expression of STAT3 did not show a statistical difference (P > 0.05). The mRNA expression of TFF3 in IEC-6 cells for 24 and 48 h was significantly up-regulated as the concentration of IL-22 increased, and the comparison between any two concentrations of IL-22 showed a significant difference (P < 0.05); the mRNA expression of STAT3 was also up-regulated, showing a significant difference between any two concentrations of IL-22 except the comparison between the groups of 10 ng/mL and 100 ng/mL. We could not measure the expression of STAT6 mRNA, and the mRNA expression of NF-κB did not show a significant difference among the groups (P > 0.05).

CONCLUSION: IL-22 may up-regulate the mRNA expression of TFF3 in IEC-6 cells through the STAT3 signal transduction pathway in a time- and dose-dependent fashion.

Th22 cells increase in poor prognosis multiple myeloma and promote tumor cell growth and survival

There is increased production of plasmacytoid dendritic cells (pDCs) in the bone marrow (BM) of multiple myeloma (MM) patients and these favor Th22 cell differentiation. Here, we found that the frequency of interleukin (IL)-22⁺IL-17^-IL-13⁺ T cells is significantly increased in peripheral blood (PB) and BM of stage III and relapsed/refractory MM patients compared with healthy donors and patients with asymptomatic or stage I/II disease. Th22 cells cloned from the BM of MM patients were CCR6⁺CXCR4⁺CCR4⁺CCR10^- and produced IL-22 and IL-13 but not IL-17. Furthermore, polyfunctional Th22-Th2 and Th22-Th1 clones were identified based on the co-expression of additional chemokine receptors and cytokines (CRTh2 or CXCR3 and IL-5 or interferon gamma [IFNγ], respectively). A fraction of MM cell lines and primary tumors aberrantly expressed the IL-22RA1 and IL-22 induced STAT-3 phosphorylation, cell growth, and resistance to drug-induced cell death in MM cells. IL-13 treatment of normal BM mesenchymal stromal cells (MSCs) induced STAT-6 phosphorylation, adhesion molecule upregulation, and increased IL-6 production and significantly favored MM cell growth compared with untreated BM MSCs. Collectively, our data show that increased frequency of IL-22⁺IL-17^-IL-13⁺ T cells correlates with poor prognosis in MM through IL-22 and IL-13 protumor activity and suggest that interference with IL-22 and IL-13 signaling pathways could be exploited for therapeutic intervention.

IL-22 produced by cancer-associated fibroblasts promotes gastric cancer cell invasion via STAT3 and ERK signaling

BACKGROUND

Interleukin-22 (IL-22) has been recently highlighted owing to its biological significance in the modulation of tissue responses during inflammation. However, the role of IL-22 in carcinogenesis has remained unclear. Here, we investigated the pathophysiological significance of IL-22 expression in gastric cancer tissues and examined the mechanism by which IL-22 promotes gastric cancer cell invasion.

METHODS

Human gastric cancer specimens were analysed by immunohistochemistry for expression of IL-22 and IL-22 receptor 1 (IL-22R1). The effects of IL-22-induced STAT3 and ERK signalling on invasive ability of gastric cancer cells were examined using a small-interfering RNA system and specific inhibitors. AGS cells were co-cultured with cancer-associated fibroblasts (CAFs) from human gastric cancer tissues and assessed by invasion assay.

RESULTS

Interleukin-22 and its receptor were expressed in α-smooth muscle actin-positive stromal cells and tumour cells at the invasive front of gastric cancer tissues, respectively. The expression of IL-22 and IL-22R1 was significantly related to lymphatic invasion. Interleukin-22 treatment promoted the invasive ability of gastric cancer cells through STAT3 and ERK activation. The invasive ability of gastric cancer cells was significantly enhanced by co-culture with IL-22-expressing CAFs.

CONCLUSIONS

Interleukin-22 produced by CAFs promotes gastric cancer cell invasion via STAT3 and ERK signalling.

The role of the IL-22/IL-22R1 axis in cancer

Interleukin-22 (IL-22) is an IL-10 family cytokine produced by T cells and innate lymphoid cells. The IL-22 signaling pathway orchestrates mucosal immune defense and tissue regeneration through pleiotropic effects including pro-survival signaling, cell migration, dysplasia and angiogenesis. While these functions can prevent initial establishment of tumors, they can also be hijacked by aggressive cancers to enhance tumor growth and metastasis. Thus, the role of the IL-22/IL-22R1 axis in cancer is complex and context-specific. Evidence of IL-22 involvement manifests as dysregulation of IL-22 expression and signaling in patients with many common cancers including those of the gut, skin, lung and liver. Unlike other cancer-associated cytokines, IL-22 has restricted tissue specificity as its unique receptor IL-22R1 is exclusively expressed on epithelial and tissue cells, but not immune cells. This makes it an attractive target for therapy as there is potential achieve anti-tumor immunity with fewer side effects. This review summarizes current findings on functions of IL-22 in association with general mechanisms for tumorigenesis as well as specific contributions to particular cancers, and ponders how best to approach further research in the field.

Interleukin-22: A Bridge Between Epithelial Innate Host Defense and Immune Cells

Interleukin-22 (IL-22), an IL-10 family cytokine, is produced by various leukocytes. The receptor of IL-22, however, is preferentially detected on peripheral tissue epithelial cells. IL-22 functions as a unique messenger from immune system to tissue epithelial cells and to regulate homeostasis of epithelia. IL-22 is able to directly enhance antimicrobial defense mechanisms in epithelial cells and to facilitate epithelial barrier repair and wound healing process. It, therefore, possesses an irreplaceable role in host defense against certain pathogens that specifically invade epithelial cells. In addition, IL-22 can help to preserve the integrity and homeostasis of various epithelial organs during infection or inflammation. The importance of its tissue-protective function is manifested in many inflammatory situations such as inflammatory bowel diseases (IBD) and hepatitis. On the other hand, as a cytokine, IL-22 is capable of induction of proinflammatory responses, especially in synergy with other cytokines. Consequently, IL-22 contributes to pathogenesis of certain inflammatory diseases for example psoriasis.

Co-expression of S. Typhi GroEL and IL-22 gene augments immune responses against Salmonella infection

Recombinant DNA vaccines represent a novel method for generating in situ expression of vaccine antigens. Intramuscular injections of naked DNA are able to elicit potent humoral and cellular immune responses but still numerous factors limit the immunogenicity of DNA vaccines. Co-expression of cytokines with antigen encoding genes in DNA vectors can improve the immune responses and modify Th1/Th2 balance. In this study, the immunomodulatory effect of Interleukin 22 (IL-22) as an adjuvant was studied by DNA vaccination with S. Typhi Heat shock protein 60 (HSP60/GroEL) in mice. Further, DNA construct of IL-22 gene fused with GroEL was developed and immunization studies were carried out in mice. DNA vaccination with GroEL alone stimulated humoral and cell-mediated immune responses. Co-immunization (IL-22+GroEL) further resulted in increase in T-cell proliferative responses, antibody titres (IgG, IgG1, IgG2a) and secretion of IFNγ (Th1), IL-1β and Th2 (IL-4, IL-6) cytokines. Co-expression (IL-22-GroEL DNA) also promoted antibody titres and cytokine levels were significantly higher as compared to co-immunized group. A reduction in bacterial load in spleen, liver and intestine was seen in all the immunized groups as compared to control, with least organ burden in fusion DNA construct group (co-expression). Improved protective efficacy (90%) against lethal challenge by Salmonella was observed with IL-22-GroEL co-expressing DNA vector as compared with plasmid encoding GroEL only (50-60%) or co-immunization group (75-80%). This study thus shows that co-expression of IL-22 and GroEL genes enhances the immune responses and protective efficacy, circumventing the need of any adjuvant.