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The mouse pathogen Citrobacter rodentium is utilized as a model organism for studying infections caused by the human pathogens enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) and to elucidate mechanisms of mucosal immunity. In response to C. rodentium infection, innate lymphoid cells and T cells secrete interleukin (IL)-22, a cytokine that promotes mucosal barrier function. IL-22 plays a pivotal role in enabling mice to survive and recover from C. rodentium infection, although the exact mechanisms involved remain incompletely understood. Here, we investigated whether particular components of the host response downstream of IL-22 contribute to the cytokine's protective effects during C. rodentium infection. In line with previous research, mice lacking the IL-22 gene (Il22-/- mice) were highly susceptible to C. rodentium infection. To elucidate the role of specific antimicrobial proteins modulated by IL-22, we infected the following knockout mice: S100A9-/- (calprotectin), Lcn2-/- (lipocalin-2), Reg3b-/- (Reg3β), Reg3g-/- (Reg3γ), and C3-/- (C3). All knockout mice tested displayed a considerable level of resistance to C. rodentium infection, and none phenocopied the lethality observed in Il22-/- mice. By investigating another arm of the IL-22 response, we observed that C. rodentium-infected Il22-/- mice exhibited an overall decrease in gene expression related to intestinal barrier integrity as well as significantly elevated colonic inflammation, gut permeability, and pathogen levels in the spleen. Taken together, these results indicate that host resistance to lethal C. rodentium infection may depend on multiple antimicrobial responses acting in concert, or that other IL-22-regulated processes, such as tissue repair and maintenance of epithelial integrity, play crucial roles in host defense to attaching and effacing pathogens.

Background: Human interleukin-22 (IL-22) is known as a "dual function" cytokine that acts as a master regulator to maintain homeostasis, structural integrity of the intestinal epithelial barrier, and shielding against bacterial pathogens. On the other hand, the overexpression of IL-22 is associated with hyper-proliferation and recruitment of pathologic effector cells, leading to tissue damage and chronic inflammation in specific diseases including inflammatory bowel disease (IBD). To study a role of IL-22-mediated signaling axis during intestinal inflammation, we generated a set of small protein blockers of IL-22R1 and verified their inhibitory potential on murine model of colitis. Methods: We used directed evolution of proteins to identify binders of human IL-22 receptor alpha (IL-22R1), designated as ABR ligands. This approach combines the assembly of a highly complex combinatorial protein library derived from small albumin-binding domain scaffold and selection of promising protein variants using ribosome display followed by large-scale ELISA screening. The binding affinity and specificity of ABR variants were analyzed on transfected HEK293T cells by flow cytometry and LigandTracer. Inhibitory function was further verified by competition ELISA, HEK-Blue IL-22 reporter cells, and murine dextran sulfate sodium (DSS)-induced colitis. Results: We demonstrate that ABR specifically recognizes transgenic IL-22R1 expressed on HEK293T cells and IL-22R1 on TNFα/IFNγ-activated HaCaT cells. Moreover, some ABR binders compete with the IL-22 cytokine and function as IL-22R1 antagonists in HEK-Blue IL22 reporter cells. In a murine model of DSS-induced acute intestinal inflammation, daily intraperitoneal administration of the best IL-22R1 antagonist, ABR167, suppressed the development of clinical and histological markers of colitis including prevention of mucosal inflammation and architecture deterioration. In addition, ABR167 reduces the DSS-induced increase in mRNA transcript levels of inflammatory cytokines such as IL-1β, IL-6, IL-10, and IL-17A. Conclusions: We developed small anti-human IL-22R1 blockers with antagonistic properties that ascertain a substantial role of IL-22-mediated signaling in the development of intestinal inflammation. The developed ABR blockers can be useful as a molecular clue for further IBD drug development. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Introduction: Colitis is an inflammatory bowel disease (IBD) characterized by immune cell dysregulation and alterations in the gut microbiome. In our previous report, we showed a natural product in cruciferous vegetables and ligand of the aryl hydrocarbon receptor (AhR), indole-3-carbinol (I3C), was able to reduce colitis-induced disease severity and microbial dysbiosis in an interleukin-22 (IL- 22) dependent manner. Methods: In the current study, we performed single-cell RNA sequencing (scRNAseq) from colonocytes during colitis induction and supplementation with I3C and show how this treatment alters expression of genes involved in IL-22 signaling. To further define the role of IL-22 signaling in I3C-mediated protection during colitis and disease-associated microbial dysbiosis, we generated mice with AhR deficiency in RAR-related orphan receptor c (Rorc)- expressing cells (AhRΔRorc) which depletes this receptor in immune cells involved in production of IL-22. Colitis was induced in wildtype (WT), AhRΔRorc, and littermate (LM) mice with or without I3C treatment. Results: Results showed AhRΔRorc mice lost the efficacy effects of I3C treatment which correlated with a loss of ability to increase IL-22 by innate lymphoid type 3 (ILC3s), not T helper 22 (Th22) cells. 16S rRNA microbiome profiling studies showed AhRΔRorc mice were unable to regulate disease-associated increases in Bacteroides, which differed between males and females. Lastly, inoculation with a specific disease-associated Bacteroides species, Bacteroides acidifaciens (B. acidifaciens), was shown to exacerbate colitis in females, but not males. Discussion: Collectively, this report highlights the cell and sex-specific role of AhR in regulating microbes that can impact colitis disease. [ABSTRACT FROM AUTHOR]

Mammalian interleukin-22 (IL-22) attenuates organismal injury by inhibiting reactive oxygen species (ROS) and impeding the NLRP3 inflammasome activation. However, the role of fish IL-22 in this process remains unclear. We characterized MaIL-22, an IL-22 homolog in blunt snout bream (Megalobrama amblycephala). Despite its low sequence identity, it shares conserved structures and close evolutionary relationships with other teleost IL-22s. Furthermore, Aeromonas hydrophila (A. hydrophila) infection leads to tissue injury in M. amblycephala immune organs and concomitantly altered Mail-22 mRNA expression, suggesting that MaIL-22 was involved in the antimicrobial immune response. To explore MaIL-22's biological functions, we produced recombinant MaIL-22 (rMaIL-22) protein and demonstrated it significantly enhanced the survival of M. amblycephala post-A. hydrophila infection. To unravel its protective mechanisms, we explored the ROS/NLRP3 inflammasome axis and its downstream signaling responses. The results showed that rMaIL-22 treatment significantly elevated antioxidant enzyme (T-SOD, CAT and GSH-PX) activities to inhibit MDA activity and scavenge ROS in visceral tissues. Meanwhile, rMaIL-22 impeded the activation of NLRP3 inflammasome by suppressing NLRP3 protein and mRNA expression. This indicated that rMaIL-22 contributed to inhibit A. hydrophila-induced activation of the ROS/NLRP3 inflammasome axis. Consistent with these findings, rMaIL-22 treatment attenuated the expression of proinflammatory cytokines (il-1β, tnf-α and il-6) and proapoptotic genes (caspase-3 and caspase-8) while promoting antiapoptotic genes (bcl-2b and mcl-1a) expression, ultimately mitigating tissue injury in visceral tissues. In conclusion, our research underscores MaIL-22's key role in microbial immune regulation, offering insights for developing IL-22-targeted therapies and breeding programs. [ABSTRACT FROM AUTHOR]

Atopic dermatitis (AD) is a prevalent and chronic inflammatory skin condition characterized by a multifaceted pathophysiology that gives rise to diverse clinical manifestations. The management of AD remains challenging due to the suboptimal efficacy of existing treatment options. Nonetheless, recent progress in elucidating the underlying mechanisms of the disease has facilitated the identification of new potential therapeutic targets and promising drug candidates. In this review, we summarize the newest data, considering multiple connections between IL-22 and AD. The presence of circulating IL-22 has been found to correlate with the severity of AD and is identified as a critical factor driving the inflammatory response associated with the condition. Elevated levels of IL-22 in patients with AD are correlated with increased proliferation of keratinocytes, alterations in the skin microbiota, and impaired epidermal barrier function. Collectively, these factors contribute to the manifestation of the characteristic symptoms observed in AD. [ABSTRACT FROM AUTHOR]

Background: Psoriasis is a chronic inflammation-associated skin disorder, and interleukin-22 (IL-22) is involved in psoriasis pathogenesis by boosting the proliferation and migration of keratinocytes. Mounting evidence has shown that circRNAs might play an important role in several aspects of psoriasis. This study is designed to explore the role and mechanism of circ_0056856 in regulating the phenotypes of IL-22-induced keratinocytes (HaCaT cells). Methods: Circ_0056856, microRNA-197-3p (miR-197-3p), Cyclin-dependent kinase 1 (CDK1), and Wilms tumor 1-associated protein (WTAP) levels were detected using real-time quantitative polymerase chain reaction (RT-qPCR). Cell viability, proliferation, migration, and invasion were analyzed using 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), Wound scratch, and Transwell assays. After being predicted by Circinteractome or TargetScan, binding between miR-197-3p and circ_0056856 or CDK1 was verified by a dual-luciferase reporter assay. CDK1 and WTAP protein levels were determined using Western blot. Interaction between WTAP and circ_0056856 was assessed using methylated RNA immunoprecipitation (MeRIP) assay. Results: Increased circ_0056856, CDK1, and WTAP were observed in psoriasis patients and IL-22-treated HaCaT cells. Moreover, circ_0056856 knockdown might repress IL-22-induced HaCaT cell proliferation, migration, and invasion in vitro. In mechanism, circ_0056856 might function as a sponge of miR-197-3p to modulate CDK1 expression, and WTAP improved circ_0056856 expression via m6A methylation. Conclusion: WTAP-guided m6A modified circ_0056856 facilitates IL-22-stimulated HaCaT cell damage through the miR-197-3p/CDK1 axis, which could provide novel insights into psoriasis treatment. [ABSTRACT FROM AUTHOR]

In maintaining organismal homeostasis, gut immunity plays a crucial role. The coordination between the microbiota and the immune system through bidirectional interactions regulates the impact of microorganisms on the host. Our research focused on understanding the relationships between substantial changes in jejunal intestinal flora and metabolites and intestinal immunity during porcine epidemic diarrhea virus (PEDV) infection in piglets. We discovered that Lactobacillus rhamnosus GG (LGG) could effectively prevent PEDV infection in piglets. Further investigation revealed that LGG metabolites interact with type 3 innate lymphoid cells (ILC3s) in the jejunum of piglets through the aryl hydrocarbon receptor (AhR). This interaction promotes the activation of ILC3s and the production of interleukin-22 (IL-22). Subsequently, IL-22 facilitates the proliferation of IPEC-J2 cells and activates the STAT3 signaling pathway, thereby preventing PEDV infection. Moreover, the AhR receptor influences various cell types within organoids, including intestinal stem cells (ISCs), Paneth cells, and enterocytes, to promote their growth and development, suggesting that AhR has a broad impact on intestinal health. In conclusion, our study demonstrated the ability of LGG to modulate intestinal immunity and effectively prevent PEDV infection in piglets. These findings highlight the potential application of LGG as a preventive measure against viral infections in livestock. IMPORTANCE We observed high expression of the AhR receptor on pig and human ILC3s, although its expression was negligible in mouse ILC3s. ILC3s are closely related to the gut microbiota, particularly the secretion of IL-22 stimulated by microbial signals, which plays a crucial regulatory role in intestinal immunity. In our study, we found that metabolites produced by beneficial gut bacteria interact with ILC3s through AhR, thereby maintaining intestinal immune homeostasis in pigs. Moreover, LGG feeding can enhance the activation of ILC3s and promote IL-22 secretion in the intestines of piglets, ultimately preventing PEDV infection. [ABSTRACT FROM AUTHOR]

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Abstract Background Human interleukin-22 (IL-22) is known as a “dual function” cytokine that acts as a master regulator to maintain homeostasis, structural integrity of the intestinal epithelial barrier, and shielding against bacterial pathogens. On the other hand, the overexpression of IL-22 is associated with hyper-proliferation and recruitment of pathologic effector cells, leading to tissue damage and chronic inflammation in specific diseases including inflammatory bowel disease (IBD). To study a role of IL-22-mediated signaling axis during intestinal inflammation, we generated a set of small protein blockers of IL-22R1 and verified their inhibitory potential on murine model of colitis. Methods We used directed evolution of proteins to identify binders of human IL-22 receptor alpha (IL-22R1), designated as ABR ligands. This approach combines the assembly of a highly complex combinatorial protein library derived from small albumin-binding domain scaffold and selection of promising protein variants using ribosome display followed by large-scale ELISA screening. The binding affinity and specificity of ABR variants were analyzed on transfected HEK293T cells by flow cytometry and LigandTracer. Inhibitory function was further verified by competition ELISA, HEK-Blue IL-22 reporter cells, and murine dextran sulfate sodium (DSS)-induced colitis. Results We demonstrate that ABR specifically recognizes transgenic IL-22R1 expressed on HEK293T cells and IL-22R1 on TNFα/IFNγ-activated HaCaT cells. Moreover, some ABR binders compete with the IL-22 cytokine and function as IL-22R1 antagonists in HEK-Blue IL22 reporter cells. In a murine model of DSS-induced acute intestinal inflammation, daily intraperitoneal administration of the best IL-22R1 antagonist, ABR167, suppressed the development of clinical and histological markers of colitis including prevention of mucosal inflammation and architecture deterioration. In addition, ABR167 reduces the DSS-induced increase in mRNA transcript levels of inflammatory cytokines such as IL-1β, IL-6, IL-10, and IL-17A. Conclusions We developed small anti-human IL-22R1 blockers with antagonistic properties that ascertain a substantial role of IL-22-mediated signaling in the development of intestinal inflammation. The developed ABR blockers can be useful as a molecular clue for further IBD drug development.

Abstract Background Colorectal cancer (CRC) is a prevalent malignancy with high morbidity and mortality rates. Previous studies have demonstrated that interleukin (IL)-22 is involved in CRC progression; however, the exact mechanism remains unclear. This study aimed to investigate the effects of IL-22 on CRC cell proliferation and metastasis. Methods IL-22 levels in the serum and tissues of CRC patients were measured using enzyme-linked immunosorbent assay (ELISA). Cell counting kit-8 (CCK-8) assay was used to detect the viability of CRC (HCT116) cells treated with different IL-22 concentrations. Colony formation, Transwell invasion, and scratch assays were employed to assess the effects of IL-22 on cell proliferation, invasion, and migration. Western blotting was performed to measure the expression levels of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), p-PI3K, p-AKT, E-cadherin, matrix metalloproteinase (MMP)-2, MMP-9, SNAI1, and TWIST1 in HCT116 cells treated with IL-22 or a PI3K inhibitor. Results ELISA results showed that the expression of IL-22 was significantly increased in the serum and tissues of CRC patients compared to controls. IL-22 treatment increased cell viability and colony formation in a concentration-dependent manner and enhanced cell invasion and migration. Western blotting analysis revealed that IL-22 stimulation upregulated p-PI3K and p-AKT expression, while total PI3K and AKT levels remained unchanged. Additionally, IL-22 also decreased E-cadherin expression and increased the expression of MMP-2, MMP-9, SNAI1, and TWIST1. Conclusions IL-22 activates the PI3K-AKT pathway and promotes HCT116 cell proliferation and metastasis. Targeting the regulation of the PI3K/AKT pathway may be a potential therapeutic strategy for CRC.

Background: Colorectal cancer (CRC) is a prevalent malignancy with high morbidity and mortality rates. Previous studies have demonstrated that interleukin (IL)-22 is involved in CRC progression; however, the exact mechanism remains unclear. This study aimed to investigate the effects of IL-22 on CRC cell proliferation and metastasis. Methods: IL-22 levels in the serum and tissues of CRC patients were measured using enzyme-linked immunosorbent assay (ELISA). Cell counting kit-8 (CCK-8) assay was used to detect the viability of CRC (HCT116) cells treated with different IL-22 concentrations. Colony formation, Transwell invasion, and scratch assays were employed to assess the effects of IL-22 on cell proliferation, invasion, and migration. Western blotting was performed to measure the expression levels of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), p-PI3K, p-AKT, E-cadherin, matrix metalloproteinase (MMP)-2, MMP-9, SNAI1, and TWIST1 in HCT116 cells treated with IL-22 or a PI3K inhibitor. Results: ELISA results showed that the expression of IL-22 was significantly increased in the serum and tissues of CRC patients compared to controls. IL-22 treatment increased cell viability and colony formation in a concentration-dependent manner and enhanced cell invasion and migration. Western blotting analysis revealed that IL-22 stimulation upregulated p-PI3K and p-AKT expression, while total PI3K and AKT levels remained unchanged. Additionally, IL-22 also decreased E-cadherin expression and increased the expression of MMP-2, MMP-9, SNAI1, and TWIST1. Conclusions: IL-22 activates the PI3K-AKT pathway and promotes HCT116 cell proliferation and metastasis. Targeting the regulation of the PI3K/AKT pathway may be a potential therapeutic strategy for CRC. [ABSTRACT FROM AUTHOR]

Background: Interleukin 24 (IL-24) has been implicated in the nociceptive signaling. However, direct evidence and the precise molecular mechanism underlying IL-24's role in peripheral nociception remain unclear. Methods: Using patch clamp recording, molecular biological analysis, immunofluorescence labeling, siRNA-mediated knockdown approach and behavior tests, we elucidated the effects of IL-24 on sensory neuronal excitability and peripheral pain sensitivity mediated by T-type Ca2+ channels (T-type channels). Results: IL-24 enhances T-type channel currents (T-currents) in trigeminal ganglion (TG) neurons in a reversible and dose-dependent manner, primarily by activating the interleukin-22 receptor 1 (IL-22R1). Furthermore, we found that the IL-24-induced T-type channel response is mediated through tyrosine-protein kinase Lyn, but not its common downstream target JAK1. IL-24 application significantly activated protein kinase A; this effect was independent of cAMP and prevented by Lyn antagonism. Inhibition of PKA prevented the IL-24-induced T-current response, whereas inhibition of protein kinase C or MAPK kinases had no effect. Functionally, IL-24 increased TG neuronal excitability and enhanced pain sensitivity to mechanical stimuli in mice, both of which were suppressed by blocking T-type channels. In a trigeminal neuropathic pain model induced by chronic constriction injury of the infraorbital nerve, inhibiting IL-22R1 signaling alleviated mechanical allodynia, which was reversed by blocking T-type channels or knocking down Cav3.2. Conclusion: Our findings reveal that IL-24 enhances T-currents by stimulating IL-22R1 coupled to Lyn-dependent PKA signaling, leading to TG neuronal hyperexcitability and pain hypersensitivity. Understanding the mechanism of IL-24/IL-22R1 signaling in sensory neurons may pave the way for innovative therapeutic strategies in pain management. [ABSTRACT FROM AUTHOR]

Chronic obstructive pulmonary disease (COPD) is a condition characterized by chronic airway inflammation and obstruction, primarily caused by tobacco smoking. Although the involvement of immune cells in COPD pathogenesis is well established, the contribution of innate lymphoid cells (ILCs) remains poorly understood. ILCs are a type of innate immune cells that participate in tissue remodeling processes, but their specific role in COPD has not been fully elucidated. During COPD, the breakdown of pulmonary elastin generates elastin peptides that elicit biological activities on immune cells. This study aimed to investigate the presence of ILC in patients with COPD and examine the impact of elastin peptides on their functionality. Our findings revealed an elevated proportion of ILC2 in the peripheral blood of patients with COPD, and a general activation of ILC as indicated by an increase in their cytokine secretion capacity. Notably, our study demonstrated that serum from patients with COPD promotes ILC2 phenotype, likely due to the elevated concentration of IL-5, a cytokine known to favor ILC2 activation. Furthermore, we uncovered that this increase in IL-5 secretion is partially attributed to its secretion by macrophages upon stimulation by elastin peptides, suggesting an indirect role of elastin peptides on ILC in COPD. These findings shed light on the involvement of ILC in COPD and provide insights into the potential interplay between elastin breakdown, immune cells, and disease progression. Further understanding of the mechanisms underlying ILC activation and their interaction with elastin peptides could contribute to the development of novel therapeutic strategies for COPD management. NEW & NOTEWORTHY Elastin-derived peptides, generated following alveolar degradation during emphysema in patients with COPD, are able to influence the response of type 2 innate lymphoid cells. We show that the orientation of innate lymphoid cells in patients with COPD is shifted toward a type 2 profile and that elastin peptides are indirectly participating in that shift through their influence of macrophages, which in turn impact innate lymphoid cells. [ABSTRACT FROM AUTHOR]

Severe acute pancreatitis (SAP) begins with premature activation of enzymes, promoted by the immune system, triggering a potential systemic inflammatory response that leads to organ failure with increased mortality and a bleak prognosis. Interleukin-22 (IL-22) is a cytokine that may have a significant role in SAP. IL-22, a member of the IL-10 cytokine family, has garnered growing interest owing to its potential tissue-protective properties. Recently, emerging research has revealed its specific effects on pancreatic diseases, particularly SAP. This paper provides a review of the latest knowledge on the role of IL-22 and its viability as a therapeutic target in SAP. Highlights: 1. Interleukin-22 (IL-22) is a member of the IL-10 family of cytokines. 2. IL-22 is a potential indicator for monitoring organ dysfunction and severity of severe acute pancreatitis (SAP). 3. IL-22 acts as a protective factor against acinar cell damage by suppressing autophagy and reducing the infiltration of inflammatory cells. 4. IL-22 alleviate SAP-induced multiorgan injury. 5. IL-22 protect SAP-induced intestinal barrier damage. [ABSTRACT FROM AUTHOR]

Background: Acute pancreatitis (AP) is one of the most common acute abdominal disorders; due to the lack of specific treatment, the treatment of acute pancreatitis, especially serious acute pancreatitis (SAP), is difficult and challenging. We will observe the changes of Interleukin -22 levels in acute pancreatitis animal models, and explore the mechanism of Interleukin -22 in acute pancreatitis. Objective: This study aims to assess the potential protective effect of Interleukin -22 on caerulein-induced acute pancreatitis and to explore its mechanism. Methods: Blood levels of amylase and lipase and Interleukin -22 were assessed in mice with acute pancreatitis. In animal model and cell model of caerulein-induced acute pancreatitis, the mRNA levels of P62 and Beclin-1 were determined using PCR, and the protein expression of P62, LC3-II, mTOR, AKT, p-mTOR, and p-AKT were evaluated through Western blot analysis. Results: Interleukin -22 administration reduced blood amylase and lipase levels and mitigated tissue damage in acute pancreatitis mice model. Interleukin -22 inhibited the relative mRNA levels of P62 and Beclin-1, and the Interleukin -22 group showed a decreased protein expression of LC3-II and P62 and the phosphorylation of the AKT/mTOR pathway. Furthermore, we obtained similar results in the cell model of acute pancreatitis. Conclusion: This study suggests that Interleukin -22 administration could alleviate pancreatic damage in caerulein-induced acute pancreatitis. This effect may result from the activation of the AKT/mTOR pathway, leading to the inhibition of autophagy. Consequently, Interleukin -22 shows potential as a treatment. [ABSTRACT FROM AUTHOR]

IntroductionColitis is an inflammatory bowel disease (IBD) characterized by immune cell dysregulation and alterations in the gut microbiome. In our previous report, we showed a natural product in cruciferous vegetables and ligand of the aryl hydrocarbon receptor (AhR), indole-3-carbinol (I3C), was able to reduce colitis-induced disease severity and microbial dysbiosis in an interleukin-22 (IL-22) dependent manner.MethodsIn the current study, we performed single-cell RNA sequencing (scRNAseq) from colonocytes during colitis induction and supplementation with I3C and show how this treatment alters expression of genes involved in IL-22 signaling. To further define the role of IL-22 signaling in I3C-mediated protection during colitis and disease-associated microbial dysbiosis, we generated mice with AhR deficiency in RAR-related orphan receptor c (Rorc)-expressing cells (AhRΔRorc) which depletes this receptor in immune cells involved in production of IL-22. Colitis was induced in wildtype (WT), AhRΔRorc, and littermate (LM) mice with or without I3C treatment. ResultsResults showed AhRΔRorc mice lost the efficacy effects of I3C treatment which correlated with a loss of ability to increase IL-22 by innate lymphoid type 3 (ILC3s), not T helper 22 (Th22) cells. 16S rRNA microbiome profiling studies showed AhRΔRorc mice were unable to regulate disease-associated increases in Bacteroides, which differed between males and females. Lastly, inoculation with a specific disease-associated Bacteroides species, Bacteroides acidifaciens (B. acidifaciens), was shown to exacerbate colitis in females, but not males. DiscussionCollectively, this report highlights the cell and sex-specific role of AhR in regulating microbes that can impact colitis disease.

Objective: Interleukin (IL)-22 is a potential therapeutic protein for the treatment of metabolic diseases such as obesity, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease due to its involvement in multiple cellular pathways and observed hepatoprotective effects. The short serum half-life of IL-22 has previously limited its use in clinical applications; however, the development of mRNA-lipid nanoparticle (LNP) technology offers a novel therapeutic approach that uses a host-generated IL-22 fusion protein. In the present study, the effects of administration of an mRNA-LNP encoding IL-22 on metabolic disease parameters was investigated in various mouse models. Methods: C57BL/6NCrl mice were used to confirm mouse serum albumin (MSA)-IL-22 protein expression prior to assessments in C57BL/6NTac and CETP/ApoB transgenic mouse models of metabolic disease. Mice were fed either regular chow or a modified amylin liver nonalcoholic steatohepatitis–inducing diet prior to receiving either LNP-encapsulated MSA-IL-22 or MSA mRNA via intravenous or intramuscular injection. Metabolic markers were monitored for the duration of the experiments, and postmortem histology assessment and analysis of metabolic gene expression pathways were performed. Results: MSA-IL-22 was detectable for ≥8 days following administration. Improvements in body weight, lipid metabolism, glucose metabolism, and lipogenic and fibrotic marker gene expression in the liver were observed in the MSA-IL-22–treated mice, and these effects were shown to be durable. Conclusions: These results support the application of mRNA-encoded IL-22 as a promising treatment strategy for metabolic syndrome and associated comorbidities in human populations.

Enhanced mortality, relapse rates, and increased prevalence of Clostridioides difficile infection (CDI) emphasize the need for better therapies and management approaches. Modulating host immune response to ameliorate CDI-associated immunopathology may provide new advantages to currently inadequate antibiotic therapies. Here, we identified progranulin (PGRN) as an important immune target upregulated in response to CDI. PGRN-deficient mice displayed dramatically higher mortality and aggravated epithelial barrier disruption compared with wild type (WT) mice after CDI despite equivalent levels of bacterial burden or toxin in the large intestine. Mechanistically, PGRN protection was mediated by IL-22 production from CD4+ T helper cells, as demonstrated by a decrease in colonic IL-22-producing CD4+ T helper cells in the intestine of PGRN-deficient mice upon CDI and a boost of IL-22-producing CD4+ T helper cells activated by PGRN ex vivo. Clinical evidence suggests that CDI patients had significantly higher serum levels of PGRN compared with healthy controls, which was significantly and positively correlated with IL-22. Our findings thus indicate a critical role for PGRN-promoted CD4+ T cell IL-22 production in shaping gut immunity and reestablishing the intestinal barrier during CDI. As an alternative to pathogen-targeted therapy, this study may provide a new host-directed therapeutic strategy to attenuate severe, refractory CDI.

Growing evidence suggests the crucial involvement of inflammation in the pathogenesis of pulmonary hypertension (PH). The current study analyzed the expression of interleukin (IL)-17a and IL-22 as potential biomarkers for PH in a preclinical rat model of PH as well as the serum levels in a PH patient collective. PH was induced by monocrotalin (60 mg/kg body weight s.c.) in 10 Sprague Dawley rats (PH) and compared to 6 sham-treated controls (CON) as well as 10 monocrotalin-induced, macitentan-treated rats (PH_MAC). Lung and cardiac tissues were subjected to histological and immunohistochemical analysis for the ILs, and their serum levels were quantified using ELISA. Serum IL levels were also measured in a PH patient cohort. IL-22 expression was significantly increased in the lungs of the PH and PH_MAC groups (p = 0.002), whereas increased IL17a expression was demonstrated only in the lungs and RV of the PH (p < 0.05) but not the PH_MAC group (p = n.s.). The PH group showed elevated serum concentrations for IL-22 (p = 0.04) and IL-17a (p = 0.008). Compared to the PH group, the PH_MAC group demonstrated a decrease in IL-22 (p = 0.021) but not IL17a (p = n.s.). In the PH patient collective (n = 92), increased serum levels of IL-22 but not IL-17a could be shown (p < 0.0001). This elevation remained significant across the different etiological groups (p < 0.05). Correlation analysis revealed multiple significant relations between IL-22 and various clinical, laboratory, functional and hemodynamic parameters. IL-22 could serve as a promising inflammatory biomarker of PH with potential value for initial diagnosis, functional classification or even prognosis estimation. Its validation in larger patients' cohorts regarding outcome and survival data, as well as the probability of promising therapeutic target structures, remains the object of further studies. [ABSTRACT FROM AUTHOR]

Many studies have investigated the antiviral activity of cytokines, including interleukin-6 (IL-6), interleukin-22 (IL-22), interleukin-32 gamma (IL-32γ), and interferon-lambda (IFN-λ) in diverse populations. This study aims to evaluate the role of these cytokines in inhibition of various human and animal viruses when administered exogenously. A comprehensive meta-analysis and systematic review were conducted on all the relevant studies from three databases. Standard mean differences (SMDs) of overall viral inhibition were used to generate the difference in the antiviral efficacy of these cytokines between control and experimental groups. A total of 4,618 abstracts for IL-6, 3,517 abstracts for IL-22, 2,160 abstracts for IL-32γ, and 1,026 abstracts for IFN-λ were identified, and 7, 4, 8, and 35 studies were included, respectively, for each cytokine. IFN-λ (SMD = 0.9540; 95% CI: 0.69–0.22) and IL-32γ (SMD = 0.459; 95% CI: 0.02–0.90) showed the highest influence followed by IL-6 (SMD = 0.456; CI: −0.04–0.95) and IL-22 (SMD = 0.244; 95% CI: −0.33–0.81). None of the cytokines represented heterogeneity (tau² > 0), but only IFN-λ indicated the funnel plot asymmetry (p = 0.0097). Results also indicated that IFN-λ and IL-32γ are more potent antivirals than IL-6 and IL-22. The collective findings of this study emphasize that exogenously administered pro-inflammatory cytokines, specifically IFN-λ and IL-32, exhibit a significant antiviral activity, thereby underscoring them as potent antiviral agents. Nonetheless, additional research is required to ascertain their clinical utility and potential for integration into combinatorial therapeutic regimens against viral infections. [ABSTRACT FROM AUTHOR]

We previously reported that an aryl hydrocarbon receptor (AhR) ligand, indole-3-carbinol (I3C), was effective at reducing colitis severity through immune cell-mediated interleukin-22 (IL-22) production. Intestinal epithelial cells (IECs) are also involved in regulating colitis, so we investigated their AhR-mediated mechanisms in the current report. A transcriptome analysis of IECs in wildtype (WT) mice revealed that during colitis, I3C regulated select mucin proteins, which could be attributed to goblet cell development. To address this, experiments under in vivo colitis (mice) or in vitro colon organoid conditions were undertaken to determine how select mucin proteins were altered in the absence or presence of AhR in IECs during I3C treatment. Comparing WT to IEC-specific AhR knockout mice (AhRΔIEC), the results showed that AhR expression was essential in IECs for I3C-mediated protection during colitis. AhR-deficiency also impaired mucin protein expression, particularly mucin 2 (Muc2), independently of IL-22. Collectively, this report highlights the important role of AhR in direct regulation of Muc2. These results provide justification for future studies aimed at determining how AhR might regulate select mucins through mechanisms such as direct transcription binding to enhance production. [ABSTRACT FROM AUTHOR]

Type 3 innate lymphoid cells (ILC3) are important in tissue homeostasis. In the gut, ILC3 repair damaged epithelium and suppress inflammation. In allogeneic hematopoietic cell transplantation (HCT), ILC3 protect against graft-versus-host disease (GvHD), most likely by restoring tissue damage and preventing inflammation. We hypothesize that supplementing HCT grafts with interleukin-22 (IL-22)-producing ILC3 may prevent acute GvHD. We therefore explored ex vivo generation of human IL-22-producing ILC3 from hematopoietic stem and progenitor cells (HSPC) obtained from adult, neonatal and fetal sources. We established a stroma-free system culturing human cord blood-derived CD34+ HSPC with successive cytokine mixes for 5 weeks. We analyzed the presence of phenotypically defined ILC, their viability, proliferation and IL-22 production (after stimulation) by flow cytometry and enzyme-linked immunosorbent assay (ELISA). We found that the addition of recombinant human IL-15 and the enhancer of zeste homolog 1/2 inhibitor UNC1999 promoted ILC3 generation. Similar results were demonstrated when UNC1999 was added to CD34+ HSPC derived from healthy adult granulocyte colony-stimulating factor mobilized peripheral blood and bone marrow, but not fetal liver. UNC1999 did not negatively impact IL-22 production in any of the HSPC sources. Finally, we observed that autologous HSPC mobilized from the blood of adults with hematological malignancies also developed into ILC3, albeit with a significantly lower capacity. Together, we developed a stroma-free protocol to generate large quantities of IL-22-producing ILC3 from healthy adult human HSPC that can be applied for adoptive transfer to prevent GvHD after allogeneic HCT. [Display omitted] [ABSTRACT FROM AUTHOR]

Interleukin-22 (IL-22) is an important cytokine in the intestinal environment. IL-22 is mainly produced by immune cells and targeted at nonimmune cells such as epithelial and stromal cells in a broad array of tissues such as - but not restricted to- the liver and adipose tissue. IL-22 therefore connects immune functions with metabolic functions of the host, and since it is induced by the microbiota, connects host functioning to the outside environment. IL-22 induces epithelial cell proliferation aiding in rapid epithelium regeneration and wound healing. Additionally, IL-22 activates antiapoptotic genes and DNA damage response pathways, enhancing epithelial cell survival. Recently, it has also been shown that IL-22 induces Paneth cell differentiation in humans. However, IL-22 can also contribute to intestinal epithelium damage and reduces microbial diversity in the intestine directly or indirectly by inducing excessive antimicrobial peptide production by epithelial cells. Moreover, IL-22 enhances angiogenesis and may therefore support tumorigenesis in the intestine. In conclusion, it appears that whether IL-22 has a beneficial or harmful effect in the mammalian intestine largely depends on its regulation. This review aims to provide a comprehensive overview of the current literature and emphasizes that IL-22 signaling outcome depends on the timing and duration of IL-22 production, the presence of it regulators such as IL-22BP, and the specific location of the cytokine production in the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

Atopic dermatitis (AD) is a prevalent and chronic inflammatory skin condition characterized by a multifaceted pathophysiology that gives rise to diverse clinical manifestations. The management of AD remains challenging due to the suboptimal efficacy of existing treatment options. Nonetheless, recent progress in elucidating the underlying mechanisms of the disease has facilitated the identification of new potential therapeutic targets and promising drug candidates. In this review, we summarize the newest data, considering multiple connections between IL-22 and AD. The presence of circulating IL-22 has been found to correlate with the severity of AD and is identified as a critical factor driving the inflammatory response associated with the condition. Elevated levels of IL-22 in patients with AD are correlated with increased proliferation of keratinocytes, alterations in the skin microbiota, and impaired epidermal barrier function. Collectively, these factors contribute to the manifestation of the characteristic symptoms observed in AD.

Background: Many neurodevelopmental abnormalities are connected to autism spectrum disorder (ASD), which can result in inflammation and elevated cytokine levels due to immune system dysregulation. Interleukin (IL)-17 A and IL-22 have been linked to the regulation of host defense against pathogens at the barrier surface, the regeneration of injured tissue, and the integration of the neurological, endocrine, and immune systems. Several studies have investigated the possible connection between IL-17 A and ASD as well as the severity of behavioral symptoms, but few of them included IL-22. Objectives: To measure serum levels of interleukin (IL)-17 A and IL-22 in children with ASD and to investigate their association with disease severity. Methods: This pilot study was performed on 24 children with ASD and 24 matched controls. Childhood Autism Rating Scale (CARS) assessed ASD severity, and serum levels of IL-17 A and IL-22 were assessed by enzyme-linked immunosorbent assay (ELISA). Results: In ASD patients, serum levels of IL-17 A and IL-22 showed a significant increase compared to controls (p-values < 0.001). We compared serum levels of IL-17 A and IL-22 according to the severity categories by CARS and could not find any significant differences (p-values > 0.05). Only IL-22 had a significant positive correlation with ASD severity by CARS scores. Conclusions: Raised serum levels of IL-17 A and IL-22 are associated with ASD; only IL-22, not IL-17 A, is correlated with ASD severity. This finding proposes IL-22 as a possible future effective target for ASD treatment. To fully comprehend the significance of these cytokines in ASD and their possible effects on ASD diagnosis and treatment, more research on a wider scale is required. [ABSTRACT FROM AUTHOR]

Background: The autonomic nervous system is linked to hyperdynamic circulation in cirrhosis and several studies have highlighted the crucial role that systemic inflammation elicits in altering sympathovagal equilibrium with the consequent reduction in heart rate variability (HRV). To investigate the correlation between time‐domain HRV parameters, serum cytokines concentrations and portal hypertension, we studied a cohort of patients with cirrhosis, accounting for etiology and treatments. Methods: In this cross‐sectional, observational cohort study, 107 outpatients with non‐alcoholic cirrhosis were assessed consecutively by abdominal ultrasound and by upper gastrointestinal endoscopy to search for esophagogastric varices. 24‐h electrocardiogram Holter monitoring with time‐domain HRV measurement (square root of the mean of successive differences of Normal‐to‐Normal [NN] [RMSSD], standard deviation or the square root of variance [SDNN] and standard deviation of the means of the NN intervals calculated over a 5‐min period [SDANN]) was performed and serum concentrations of osteopontin (OPN), interleukin (IL)‐22, IL‐6, IL‐1Ra and IL‐17 were obtained in all patients. Results: IL‐6, OPN, IL‐22 and IL‐1Ra concentrations in cirrhotic patients were associated with disease severity expressed by Child‐Pugh and MELD score, to some portal hypertension's indirect signs and some of its complications. A significant increase in systemic concentrations of OPN in patients with hepatocellular carcinoma was encountered. SDANN and SDNN values were indirectly related to serum levels of IL‐6, OPN, IL‐1Ra and IL‐22. Conclusions: This study underlines the interaction between the alteration of the ANS and the activation of inflammatory pathways that characterize cirrhosis taking into account clinical characteristics and treatments. [ABSTRACT FROM AUTHOR]

Objective To explore the expression and significance of interleukin-22（IL-22） and IL-22 binding protein（IL-22BP） in patients with diabetes mellitus type 2（T2DM） complicated with diabetic retinopathy（DR）.Methods A total of 124 hospitalized patients with T2DM in the Department of Endocrinology of this hospital from March to October, 2022 were enrolled as the research objects.The fundus photography results were consistent with 48 patients with DR（the DR group） and 76 patients without DR（the DM group）.The general clinical characteristics, routine biochemical indexes, as well as the levels of IL-22 and IL-22BP were compared between the two groups.The correlation between IL-22,IL-22BP and other indexes, the related risk factors of DR and the diagnostic value of IL-22 and IL-22BP in DR were analyzed.Results Compared with the DM group, the levels of fasting plasma glucose（FPG）,glycosylated hemoglobin（HbA1c）,urea nitrogen（BUN）,creatinine（Cr） and IL-22 in the DR group were significantly increased（P＜0.01）,while the levels of albumin（ALB） and IL-22BP were decreased（P＜0.05）.The level of IL-22 in peripheral blood of patients in the DR group was positively correlated with FPG level and HbA1c level（ρ=0.46,0.35,P＜0.01）,and negatively correlated with IL-22BP level（ρ=-0.46,P＜0.01）.The level of IL-22BP was negatively correlated with FPG level and HbA1c level（ρ=-0.45,-0.32,P＜0.05） and positively correlated with ALT level（ρ=0.31,P＜0.05）.After adjusting for age, gender, and other factors, IL-22,IL-22BP,FPG,HbA1c, ALB and Cr were identified as independent risk factors for DR（P＜0.05）.The receiver operating characteristic（ROC） curve showed that the area under curve（AUC） values of IL-22 and IL-22BP were 0.833 and 0.829,respectively.The optimal cut-off values of IL-22 and IL-22BP were 82.17 pg/mL and 743.89 ng/mL,the specificity was 85.4% and 89.6%,and the sensitivity was 34.2% and 39.5%,respectively.However, IL-22 and IL-22BP combined with FPG and HbA1c could further improve the diagnostic efficiency of DR.Conclusion IL-22 and IL-22BP are closely related to the occurrence and development of T2DM complicated with DR,and they may be potential markers and targets for assist its diagnosis and treatment. [ABSTRACT FROM AUTHOR]

BackgroundThe occurrence of eczema is related to helper T 22 (Th22) cytokine disorder, and Th22 mainly secretes interleukin-22 (IL-22). This study aims to investigate the predictive value of umbilical cord blood IL-22 levels on the onset of eczema in infants within 42 days.Study designThe study selected 157 full-term healthy neonates born between September 2020 and May 2021. Cord blood was collected immediately after birth to determine IL-22 levels, and the infants were followed up for 42 days to assess the incidence of eczema.ResultsAmong the 157 infants who completed the 42-day follow-up, 86 developed eczema and 71 did not. The level of IL-22 in the umbilical cord blood of the eczema group was lower than that of the non-eczema group (p

Many studies have investigated the antiviral activity of cytokines, including interleukin-6 (IL-6), interleukin-22 (IL-22), interleukin-32 gamma (IL-32γ), and interferon-lambda (IFN-λ) in diverse populations. This study aims to evaluate the role of these cytokines in inhibition of various human and animal viruses when administered exogenously. A comprehensive meta-analysis and systematic review were conducted on all the relevant studies from three databases. Standard mean differences (SMDs) of overall viral inhibition were used to generate the difference in the antiviral efficacy of these cytokines between control and experimental groups. A total of 4,618 abstracts for IL-6, 3,517 abstracts for IL-22, 2,160 abstracts for IL-32γ, and 1,026 abstracts for IFN-λ were identified, and 7, 4, 8, and 35 studies were included, respectively, for each cytokine. IFN-λ (SMD = 0.9540; 95% CI: 0.69–0.22) and IL-32γ (SMD = 0.459; 95% CI: 0.02–0.90) showed the highest influence followed by IL-6 (SMD = 0.456; CI: −0.04–0.95) and IL-22 (SMD = 0.244; 95% CI: −0.33–0.81). None of the cytokines represented heterogeneity (tau² > 0), but only IFN-λ indicated the funnel plot asymmetry (p = 0.0097). Results also indicated that IFN-λ and IL-32γ are more potent antivirals than IL-6 and IL-22. The collective findings of this study emphasize that exogenously administered pro-inflammatory cytokines, specifically IFN-λ and IL-32, exhibit a significant antiviral activity, thereby underscoring them as potent antiviral agents. Nonetheless, additional research is required to ascertain their clinical utility and potential for integration into combinatorial therapeutic regimens against viral infections.

Paneth cells are intestinal epithelial cells that release antimicrobial peptides, such as α-defensin as part of host defense. Together with mesenchymal cells, Paneth cells provide niche factors for epithelial stem cell homeostasis. Here, we report two subtypes of murine Paneth cells, differentiated by their production and utilization of fucosyltransferase 2 (Fut2), which regulates α(1,2)fucosylation to create cohabitation niches for commensal bacteria and prevent invasion of the intestine by pathogenic bacteria. The majority of Fut2- Paneth cells were localized in the duodenum, whereas the majority of Fut2+ Paneth cells were in the ileum. Fut2+ Paneth cells showed higher granularity and structural complexity than did Fut2- Paneth cells, suggesting that Fut2+ Paneth cells are involved in host defense. Signaling by the commensal bacteria, together with interleukin 22 (IL-22), induced the development of Fut2+ Paneth cells. IL-22 was found to affect the α-defensin secretion system via modulation of Fut2 expression, and IL-17a was found to increase the production of α-defensin in the intestinal tract. Thus, these intestinal cytokines regulate the development and function of Fut2+ Paneth cells as part of gut defense.

Periodontitis is a chronic inflammatory disease characterized by the destruction of tooth-supporting tissues. The gingival epithelium is the first barrier of periodontal tissue against oral pathogens and harmful substances. The structure and function of epithelial lining are essential for maintaining the integrity of the epithelial barrier. Abnormal apoptosis can lead to the decrease of functional keratinocytes and break homeostasis in gingival epithelium. Interleukin-22 is a cytokine that plays an important role in epithelial homeostasis in intestinal epithelium, inducing proliferation and inhibiting apoptosis, but its role in gingival epithelium is poorly understood. In this study, we investigated the effect of interleukin-22 on apoptosis of gingival epithelial cells during periodontitis. Interleukin-22 topical injection and Il22 gene knockout were performed in experimental periodontitis mice. Human gingival epithelial cells were co-cultured with Porphyromonas gingivalis with interleukin-22 treatment. We found that interleukin-22 inhibited apoptosis of gingival epithelial cells during periodontitis in vivo and in vitro, decreasing Bax expression and increasing Bcl-xL expression. As for the underlying mechanisms, we found that interleukin-22 reduced the expression of TGF-β receptor type II and inhibited the phosphorylation of Smad2 in gingival epithelial cells during periodontitis. Blockage of TGF-β receptors attenuated apoptosis induced by Porphyromonas gingivalis and increased Bcl-xL expression stimulated by interleukin-22. These results confirmed the inhibitory effect of interleukin-22 on apoptosis of gingival epithelial cells and revealed the involvement of TGF-β signaling pathway in gingival epithelial cell apoptosis during periodontitis. [ABSTRACT FROM AUTHOR]

To investigate the expression and clinical significance of peripheral blood interleukin (IL)-17A, IL-22, T cell immunoglobulin molecule-3 (Tim-3), and galectin-9 (gal-9) in children with infectious mononucleosis (IM) caused by the Epstein–Barr virus (EBV). Peripheral blood of 54 children with IM (case group) was collected and divided into a liver damage group and a non-liver damage group. During the same period, 20 healthy children were in the control group. IL-17A and IL-22 were measured by enzyme-linked immunosorbent assay. Real-time quantitative polymerase chain reaction was used to measure the mRNA expression of Tim-3 and gal-9. Their correlation with clinical indicators was then analyzed. The IL-17A expression level was higher in the case group than in the control group, while Tim-3, gal-9, and IL-22 were lower than those in the control group. Tim-3 was positively correlated with gal-9, but negatively correlated with IL-17A. Tim-3 and gal-9 were positively correlated with CD4+/CD8+ cells. Conversely, they were negatively correlated with CD3+, CD3+CD8+, white blood cell, lymphocyte (L), alanine transaminase (ALT), aspartate transaminase (AST), glutamyl transpeptidase (GGT), and lactate dehydrogenase (LDH). In the case group, IL-17A was positively correlated with L, GGT, and LDH, but negatively correlated with the natural killer (NK) cell count. IL-17A and IL-22 were positively correlated with CD3+, CD3+CD8+, ALT, and AST, but they were negatively correlated with the ratio of CD4+/CD8+. In the liver damage group, IL-17A, IL-22, CD3+, CD3+CD8+, immunoglobulin A (IgA), IgG, IgM, L, ALT, AST, GGT, LDH, and α-hydroxybutyrate levels were higher than those in the non-liver damage group. However, Tim-3, gal-9, the ratio of CD4+/CD8+, and NK were lower than those in the non-liver damage group. IL-17A, IL-22, Tim-3, and gal-9 are involved in the immune pathogenesis of IM caused by EBV infection in children, which may be related to immune liver injury. [ABSTRACT FROM AUTHOR]

Background: nutritional factors might affect the number and function of immune cells for instance the production of cytokines and immunoglobulins. Ramadan fasting is intermittent abstinence from eating and drinking for almost four weeks. Aim: The present study aimed to investigate the influence of intermittent fasting on serum IgA, salivary IgA (sIgA), interleukin (IL)-17, and IL-22 levels. Methods: 40 healthy men aged 19–29 years were evaluated before and during the fourth week of Ramadan fasting for IgA levels by the nephelometric method as well as salivary IgA (sIgA), IL-17, and IL-22 amounts using enzyme-linked immunosorbent assay (ELISA). Results: serum IgA levels reduced significantly at the end of Ramadan fasting (225.8 ± 87 vs. 196 ± 70 mg/dl) (p-value<0.001); however, sIgA amounts did not differ between before and the last week of Ramadan. Serum IL-17 reduced significantly (2.93 ± 1.51 vs. 2.17 ± 1.33 pg/ml) (p-value = 0.006) whereas IL-22 levels remained approximately unchanged. Summary: four weeks of intermittent fasting during Ramadan reduced the serum levels of IgA and IL-17 but did not affect the production of sIgA and IL-22. These findings indicate a limited impact of intermittent fasting on mucosal immunity. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the mechanism of iron on intestinal epithelium development of suckling piglets. Compared with newborn piglets, 7-day-old and 21-day-old piglets showed changes in the morphology of the jejunum, increased proliferation, differentiated epithelial cells, and expanded enteroids. Intestinal epithelium maturation markers and iron metabolism genes were significantly changed. These results suggest that lactation is a critical stage in intestinal epithelial development, accompanied by changes in iron metabolism. In addition, deferoxamine (DFO) treatment inhibited the activity of intestinal organoids at passage 4 (P4) of 0-day-old piglets, but no significant difference was observed in epithelial maturation markers at passage 1 (P1) and P4, and only argininosuccinate synthetase 1 (Ass1) and β-galactosidase (Gleb) were up-regulated at passage 7 (P7). These results in vitro show that iron deficiency may not directly affect intestinal epithelium development through intestinal stem cells (ISCs). The iron supplementation significantly down-regulated the mRNA expression of interleukin-22 receptor subunit alpha-2 (IL-22RA2) in the jejunum of piglets. Furthermore, the mRNA expression of IL-22 in 7-day-old piglets was significantly higher than that in 0-day-old piglets. Adult epithelial markers were significantly up-regulated in organoids treated with recombinant murine cytokine IL-22. Thus, IL-22 may play a key role in iron-affecting intestinal epithelium development. [ABSTRACT FROM AUTHOR]

We previously reported that an aryl hydrocarbon receptor (AhR) ligand, indole-3-carbinol (I3C), was effective at reducing colitis severity through immune cell-mediated interleukin-22 (IL-22) production. Intestinal epithelial cells (IECs) are also involved in regulating colitis, so we investigated their AhR-mediated mechanisms in the current report. A transcriptome analysis of IECs in wildtype (WT) mice revealed that during colitis, I3C regulated select mucin proteins, which could be attributed to goblet cell development. To address this, experiments under in vivo colitis (mice) or in vitro colon organoid conditions were undertaken to determine how select mucin proteins were altered in the absence or presence of AhR in IECs during I3C treatment. Comparing WT to IEC-specific AhR knockout mice (AhRΔIEC), the results showed that AhR expression was essential in IECs for I3C-mediated protection during colitis. AhR-deficiency also impaired mucin protein expression, particularly mucin 2 (Muc2), independently of IL-22. Collectively, this report highlights the important role of AhR in direct regulation of Muc2. These results provide justification for future studies aimed at determining how AhR might regulate select mucins through mechanisms such as direct transcription binding to enhance production.

Polycystic ovary syndrome (PCOS) is known as a prevalent but complicated gynecologic disease throughout the reproductive period. Typically, it is characterized by phenotypic manifestations of hyperandrogenism, polycystic ovary morphology, and persistent anovulation. For now, the therapeutic modality of PCOS is still a formidable challenge. Metabolic aberrations and immune challenge of chronic low-grade inflammatory state are significant in PCOS individuals. Recently, interleukin-22 (IL-22) has been shown to be therapeutically effective in immunological dysfunction and metabolic diseases, which suggests a role in the treatment of PCOS. In this review, we outline the potential mechanisms and limitations of IL-22 therapy in PCOS-related metabolic disorders including its regulation of insulin resistance, gut barrier, systemic inflammation, and hepatic steatosis to generate insights into developing novel strategies in clinical practice. [ABSTRACT FROM AUTHOR]

Spinal cord injury (SCI) starts with a mechanical and/or bio-chemical insult, followed by a secondary phase, leading progressively to severe collapse of the nerve tissue. Compared to the peripheral nervous system, injured spinal cord is characterized by weak axonal regeneration, which leaves most patients impaired or paralyzed throughout lifetime. Therefore, confining, alleviating, or reducing the expansion of secondary injuries and promoting functional connections between rostral and caudal regions of lesion are the main goals of SCI therapy. Interleukin 10 (IL-10), as a pivotal anti-inflammatory and immunomodulatory cytokine, exerts a wide spectrum of positive effects in the treatment of SCI. The mechanisms underlying therapeutic effects mainly include anti-oxidative stress, limiting excessive inflammation, anti-apoptosis, antinociceptive effects, etc. Furthermore, IL-10 displays synergistic effects when combined with cell transplantation or neurotrophic factor, enhancing treatment outcomes. This review lists pleiotropic mechanisms underlying IL-10-mediated neuroprotection after SCI, which may offer fresh perspectives for clinical translation. [ABSTRACT FROM AUTHOR]

Organ fibrosis caused by chronic allograft rejection is a major concern in the field of transplantation. Macrophage-to-myofibroblast transition plays a critical role in chronic allograft fibrosis. Adaptive immune cells (such as B and CD4+ T cells) and innate immune cells (such as neutrophils and innate lymphoid cells) participate in the occurrence of recipient-derived macrophages transformed to myofibroblasts by secreting cytokines, which eventually leads to fibrosis of the transplanted organ. This review provides an update on the latest progress in understanding the plasticity of recipient-derived macrophages in chronic allograft rejection. We discuss here the immune mechanisms of allograft fibrosis and review the reaction of immune cells in allograft. The interactions between immune cells and the process of myofibroblast formulation are being considered for the potential therapeutic targets of chronic allograft fibrosis. Therefore, research on this topic seems to provide novel clues for developing strategies for preventing and treating allograft fibrosis. [ABSTRACT FROM AUTHOR]

Objective: To observe the clinical effect of Tiaowei Chengqi Decoction add and subtract combined with Kushen Decoction medicated bath in treating plaque psoriasis (wind-heat-blood-dryness syndrome). Methods: A total of 96 patients with plaque psoriasis who were treated in the Second Affiliated Hospital of Hunan University of Traditional Chinese Medicine from March 2020 to March 2021 were selected and divided into control group (n=48, basic symptomatic treatment) and observation group (n=48, given Tiaowei Chengqi Decoction add and subtract combined with Kushen Decoction combined medicated bath treatment on the basis of the control group) according to the tossing coins method. The clinical efficacy, inflammatory response [tumor necrosis factor-α(TNF-α), interleukin-17 (IL-17), interleukin-22 (IL-22)], serum vascular endothelial growth factor (VEGF) and transforming growth factor β1 (TGF-β1) levels, psoriasis area, severity index (PASI) and degree of pruritus, and adverse reactions in the two groups were compared. Results: Compared with 77.08% in the control group, the total effective rate 93.75% in the observation group was higher (P<0.05). The IL-17, TNF-α, IL-22 levels, PASI and pruritus degree in both groups after treatment were lower than those before treatment, and the observation group was lower than the control group (P<0.05). VEGF and TGF-β1 levels in both groups after treatment were decreased than those before treatment, and the observation group was lower than the control group (P<0.05). The total incidence of adverse reactions in the observation group was 10.42%, which was slightly higher than that in the control group (4.17%), and after comparison, there was no statistical difference between the two groups (P>0.05). Conclusion: For patients with plaque psoriasis, comprehensive treatment of Tiaowei Chengqi Decoction add and subtract combined with Kushen Decoction has a good clinical effect, can reduce inflammation, prevent fibrosis and inhibit neovascularization, improve PASI score and itching degree,with good security. [ABSTRACT FROM AUTHOR]

The innate immune system provides a defense against invading pathogens by inducing various interferon (IFN)-stimulated genes (ISGs). We recently reported that tripartite motif protein 25 (TRIM25), an important ISG, was highly upregulated in duck embryo hepatocyte cells (DEFs) after infection with duck viral hepatitis A virus type 1 (DHAV-1). However, the mechanism of upregulation of TRIM25 remains unknown. Here we reported that interleukin-22 (IL-22), whose expression was highly facilitated in DEFs and various organs of 1-day-old ducklings after DHAV-1 infection, highly enhanced the IFN-λ-induced production of TRIM25. The treatment with IL-22 neutralizing antibody or the overexpression of IL-22 highly suppressed or facilitated TRIM25 expression, respectively. The phosphorylation of signal transducer and activator of transcription 3 (STAT3) was crucial for the process of IL-22 enhancing IFN-λ-induced TRIM25 production, which was suppressed by WP1066, a novel inhibitor of STAT3 phosphorylation. The overexpression of TRIM25 in DEFs resulted in a high production of IFNs and reduced DHAV-1 replication, whereas the attenuated expression of IFNs and facilitated replication of DHAV-1 were observed in the RNAi group, implying that TRIM25 defended the organism against DHAV-1 propagation by inducing the production of IFNs. In summary, we reported that IL-22 activated the phosphorylation of STAT3 to enhance the IFN-λ-mediated TRIM25 expression and provide a defense against DHAV-1 by inducing IFN production. [ABSTRACT FROM AUTHOR]

Myocardial infarction (MI) can result in fatal myocardial rupture or heart failure due to adverse remodeling and dysfunction of the left ventricle. Although recent studies have shown that exogenous interleukin (IL)-22 shows cardioprotective effect after MI, the pathophysiological significance of endogenous IL-22 is unknown. In this study, we investigated the role of endogenous IL-22 in a mouse model of MI. We produced MI model by permanent ligation of the left coronary artery in wild-type (WT) and IL-22 knock-out (KO) mice. The post-MI survival rate was significantly worse in IL-22KO mice than in WT mice due to a higher rate of cardiac rupture. Although IL-22KO mice exhibited a significantly greater infarct size than WT mice, there was no significant difference in left ventricular geometry or function between WT and IL-22KO mice. IL-22KO mice showed increase in infiltrating macrophages and myofibroblasts, and altered expression pattern of inflammation- and extracellular matrix (ECM)-related genes after MI. While IL-22KO mice showed no obvious changes in cardiac morphology or function before MI, expressions of matrix metalloproteinase (MMP)-2 and MMP-9 were increased, whereas that of tissue inhibitor of MMPs (TIMP)-3 was decreased in cardiac tissue. Protein expression of IL-22 receptor complex, IL-22 receptor alpha 1 (IL-22R1) and IL-10 receptor beta (IL-10RB), were increased in cardiac tissue 3 days after MI, regardless of the genotype. We propose that endogenous IL-22 plays an important role in preventing cardiac rupture after MI, possibly by regulating inflammation and ECM metabolism. [ABSTRACT FROM AUTHOR]

Intestinal ischemia/reperfusion (I/R) injury (IIRI) is associated with high morbidity and mortality. Salvianolic acid B (Sal-B) could exert neuroprotective effects on reperfusion injury after cerebral vascular occlusion, but its effect on IIRI remains unclear. This study set out to investigate the protective effects of Sal-B on IIRI in rats. The rat IIRI model was established by occluding the superior mesenteric artery and reperfusion, and they were pretreated with Sal-B and aryl hydrocarbon receptor (AhR) antagonist CH-223191 before surgery. Pathological changes in rat ileum, IIRI degree, and intestinal cell apoptosis were evaluated through hematoxylin-eosin staining, Chiu's score scale, and TUNEL staining, together with the determination of caspase-3, AhR protein level in the nucleus, and STAT6 phosphorylation by Western blotting. The levels of inflammatory cytokines (IL-1β/IL-6/TNF-α) and IL-22 were determined by ELISA and RT-qPCR. The contents of superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) in intestinal tissues were determined by spectrophotometry. Sal-B alleviated IIRI in rats, evidenced by slight villi shedding and villi edema, reduced Chiu's score, and diminished the number of TUNEL-positive cells and caspase-3 expression. SAL-B alleviated inflammation and oxidative stress (OS) responses induced by IIRI. Sal-B promoted IL-22 secretion by activating AhR in intestinal tissue after IIRI. Inhibition of AhR activation partially reversed the protective effect of Sal-B on IIRI. Sal-B promoted STAT6 phosphorylation by activating the AhR/IL-22 axis. Sal-B plays a protective role against IIRI in rats by activating the AhR/IL-22/STAT6 axis, which may be achieved by reducing the intestinal inflammatory response and OS responses. [ABSTRACT FROM AUTHOR]

Background: Rheumatoid Arthritis (RA) is a chronic autoimmune disease that primarily affects small joints, resulting in joint inflammation, pain, and limited mobility. The identification of novel biomarkers specific to RA could enhance early diagnosis and treatment and also improve the monitoring of the disease activity and treatment response. In this study, the levels of IL-22 were measured in 133 patients with inflammatory arthritis using the ELISA method with the aim of assessing the diagnostic value of IL-22 in the diagnosis of RA and evaluating the disease activity. The findings revealed that serum IL-22 levels were significantly higher in RA patients compared to patients with other types of inflammatory arthritis. Additionally, positive correlations were observed between IL-22 and disease activity scores as determined by CDAI, DAS-28 ESR, and DAS-28 CRP. Notably, when IL-22 was used as a diagnostic tool, with a cut-off value of ≥ 26.9 pg/ml, it exhibited a sensitivity of 83%, specificity of 75%, and an AUC of 0.838. Furthermore, significant associations were found between IL-22 levels and the age of RA patients, while no significant correlations were observed with gender, BMI, and smoking index. It is noteworthy that IL-22 levels were significantly correlated with ESR, RF titer, and ACPA levels. Consequently, IL22 can be regarded as a valuable biomarker for diagnosing RA and evaluating disease activity. Subjects and method: This cross-sectional study was conducted from September 2022 to January 2023, involving 133 patients with inflammatory arthritis, including RA and other forms of inflammatory arthritis. All patients were recruited from As-Sader Teaching Hospital in Najaf. The ages of the patients included in the present study range from 20 to 70 years, with a sample comprising 116 females and 17 males. Results: The higher median (IQR) value of IL-22 was observed among the RA patients [36.9 (28.6-63.7) pg/ml] compared to that of the other patients with inflammatory arthritis [23.6 (19.8-26.8) pg/ml]. The difference between the two groups of patients was highly significant (P < 0.0001). Among the RA patients, a highly significant difference in the median (IQR) level of IL-22 was observed among the disease activity groups according to CDAI, DAS-28 ESR, and DAS-28 CRP (P < 0.0001). Conclusion: Interleukin-22 can be regarded as a reliable biomarker for the diagnosis of RA and holds potential for assessing disease activity. [ABSTRACT FROM AUTHOR]

Smoking is a major risk factor for pulmonary diseases that include chronic obstructive pulmonary diseases (COPD) and cancer. Nicotine is the toxic and addictive component of tobacco products, like cigarettes, that negatively affects the immune system. Here, we examined the effect of nicotine on the IL-22 pathway that protects lung function by increasing transepithelial resistance and epithelial cell regeneration and repair. Our results indicate that exposure to nicotine impairs the regenerative capacity of primary bronchial epithelial cells in scratch assays. IL-22 at 100 ng/ml significantly improved wound healing in epithelial cells; however, the exposure to nicotine hampered the IL-22-mediated effect of wound healing. Investigation into the mechanisms showed that IL-22 receptor, IL-22Rα1, was downregulated in the presence of nicotine as determined by q-PCR and flow cytometry. We also investigated the effect of nicotine on IL-22 production by T cells. Results indicate that nicotine inhibited the secretion of IL-22 from T cells in response to aryl hydrocarbon receptor (AHR) ligand, FICZ. Altogether, the data suggests that nicotine negatively influences the IL-22-IL-22R axis. This impairment may contribute to the nicotine-mediated detrimental effects on lung function.

The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway plays a critical role in orchestrating immune and inflammatory responses, and it is essential for a wide range of cellular processes, including differentiation, cell growth, and apoptosis. Over the years, this pathway has been heavily investigated due to its key role in the pathogeneses of several chronic inflammatory conditions, e.g., psoriasis, atopic dermatitis (AD), and inflammatory bowel diseases (IBDs). Nevertheless, the impact of this pathway on the pathogenesis of inflammatory conditions remains unclear. This review describes the role of the JAK/STAT signaling pathway in the pathogenesis of inflammatory diseases such as psoriasis (Pso), psoriatic arthritis (PsA), AD, and IBD with a focus on ulcerative colitis (UC) and briefly resumes the use of JAK inhibitors in their clinical management. [ABSTRACT FROM AUTHOR]

Diabetic nephropathy (DN), the principal pathogeny of end-stage renal disease (ESRD), is related to metabolic disorders, chronic inflammation, and oxidative stress. It was reported that high expression of interleukin-17A (IL-17A) was intimately related to the progression of DN, and targeting IL-17A exhibited regulating effects on inflammation and autoimmunity but had only limited impact on the oxidative stress damage in DN. Recent studies showed that interleukin-22 (IL-22) could inhibit mitochondrial damage and inflammatory response. Thus, the cytokine IL-22 was first fused to anti-IL-17A antibody for endowing the antibody with the anti-hyperglycemia and anti-inflammation activity. Our study demonstrated that the fusion molecule, anti-IL17A/IL22 fusion protein, could not only lead to the increase of M1 macrophages and the decrease of M2 macrophages, further improving the immune microenvironment, but also prevent the loss of mitochondrial membrane potential by reducing the production of ROS in murine DN model. In addition, the fusion protein could block TRAF6/NF-κB and AKT/ROS/TXNIP signaling pathways, further synergistically restraining the production of NLRP3, thus suppressing the inflammatory response and playing beneficial effect on slowing down the progression of DN. In conclusion, our findings demonstrated that the bifunctional IL-17A antibody and IL-22 fusion protein were of great benefit to DN, which highlighted a potential therapeutic strategy. Key points: • Anti-IL17A/IL22 fusion protein could improve the immune microenvironment and reduce the production of ROS. • Anti-IL17A/IL22 fusion protein could block TRAF6/NF-κB and AKT/ROS/TXNIP signaling pathways and then restrain the activation of NLRP3. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Alcohol‐associated hepatic fibrosis is a widespread liver disease with no effective treatment. Recent studies have indicated that interleukin‐22 (IL‐22) can ameliorate alcohol‐associated liver disease. However, the mechanism underlying the role of IL‐22 in alcohol‐associated hepatic fibrosis remains unclear. Therefore, we investigated the effect of IL‐22 in a mouse model of alcohol‐associated hepatic fibrosis and its underlying mechanisms. Methods: Alcohol‐associated hepatic fibrosis was induced by feeding male C57BL/6J mice with a Lieber‐DeCarli liquid diet containing 4% ethyl alcohol for 8 weeks and injecting them with 5% tetrachloromethane (CCl4) intraperitoneally for the last 4 weeks. During the last 4 weeks, IL‐22 was also administered. We investigated the role of IL‐22 in autophagy and the PI3K/AKT/mTOR signaling pathway using a 3‐methyladenine intraperitoneal injection in the mice treated with IL‐22. The effects of IL‐22 on alcohol‐associated hepatic fibrosis, autophagy‐related gene expression, and PI3K/AKT/mTOR activity were assessed using histopathology, biochemical analysis, transmission electron microscopy, quantitative real‐time PCR, immunohistochemistry, and western blotting. Results: Mice treated with ethanol and CCl4 displayed distinct liver injuries, including hepatocyte necrosis, inflammatory cell infiltration, and hepatic fibrosis, which were substantially attenuated by IL‐22 treatment. In addition, we found that IL‐22 regulated the expression of autophagy‐related genes and inhibited the PI3K/AKT/mTOR pathway, as evidenced by the reduction in p‐PI3K, p‐AKT, and p‐mTOR expression after IL‐22 treatment. Conclusions: IL‐22 exerts a marked protective effect against alcohol‐associated hepatic fibrosis. Its effect may be partly related to the alteration of autophagy‐related gene expression and inhibition of the PI3K/AKT/mTOR pathway in the liver. [ABSTRACT FROM AUTHOR]

Interleukin 22 (IL-22) plays a role in inflammatory diseases. However, whether IL-22 affects the function of ovarian granulosa cells (GCs) and its relationship with Polycystic Ovary Syndrome (PCOS)remains unclear. We investigated the level of IL-22 in human follicular fluid using ELISA. The expression and localization of the IL-22 receptor 1 (IL-22R1) in GCs were investigated by RT-PCR and immunofluorescence staining, respectively. The proliferation of KGN cells (human GCs line) was assessed by CCK-8 assay and EdU assay after treatment with recombinant human IL-22 (rhIL-22) and lipopolysaccharide (LPS). Apoptosis was assessed using flow cytometry. Apoptotic proteins and steroidogenic genes were detected by western blotting. ELISA's results showed that compared with the control group, PCOS patients showed lower expression of IL-22 in follicular fluid. Immunofluorescence showed that IL-22R1 is expressed and localized in human granulosa cell membranes. IL-22 promoted cell proliferation and reversed LPS-induced inhibition of cell proliferation. IL-22 alone did not affect apoptotic or steroidogenic protein expression, however, it reversed LPS-induced apoptosis via downregulation of Bcl-2, upregulation of Bax and cleaved caspase-3, and restoration of LPS-downregulated StAR, CYP11A1, and CYP19A1 expression. Western blotting confirmed that IL-22 activated the JAK2/STAT3 signaling. IL-22 promotes cell proliferation, inhibits apoptosis, and regulates KGN cell steroidogenesis confronted with LPS, and decreased IL-22 may be involved in the development of PCOS. [ABSTRACT FROM AUTHOR]