IL-22: a promising candidate to inhibit viral-induced liver disease progression and hepatocellular carcinoma

Extracellular Vesicles Contribute to Viral-Induced Hepatocellular Carcinoma: Understanding Their Involvement in Viral Hepatitis and Their Potential as Biomarkers for Early Hepatocellular Carcinoma Detection

The high global prevalence of hepatitis B and hepatitis C and the poor prognosis of hepatitis B and hepatitis C-associated hepatocellular carcinoma (HCC), necessitates the early diagnosis and treatment of the disease. Recent studies show that cell-to-cell communication via extracellular vesicles (EVs) is involved in the HCC progression. The objective of the following study was to explore the role of EVs in the progression of viral-induced HCC and investigate their potential for the early diagnosis of cancer. First, the mRNA derived from EVs of HCC patients was compared to the mRNA derived from EVs from the healthy controls. Expression analysis of ANGPTL3, SH3BGRL3, and IFITM3 genes from the EVs was done. Afterward, to confirm whether hepatocytes can uptake EVs, HuH7 cells were exposed to EVs, and the expression analysis of downstream target genes (AKT, TNF-α, and MMP-9) in Huh7 cells was done. Transcriptional analysis showed that in the EVs from HCC patients, the expression levels of ANGPTL3, SH3BGRL3, and IFITM3 were significantly increased by 2.62-, 4.3-, and 9.03-folds, respectively. The downstream targets, AKT, TNF-α, and MMP-9, also showed a considerable change of 4.1-, 1.46-, and 5.05-folds, respectively, in Huh7 cells exposed to HCC EVs. In conclusion, the following study corroborates the role of EVs in HCC progression. Furthermore, the significant alteration in mRNA levels of the selected genes demonstrates their potential to be used as possible biomarkers for the early diagnosis of HCC.

Interleukin-22 facilitates the interferon-λ-mediated production of tripartite motif protein 25 to inhibit replication of duck viral hepatitis A virus type 1

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.

Deciphering STAT3 signaling potential in hepatocellular carcinoma: tumorigenesis, treatment resistance, and pharmacological significance

Hepatocellular carcinoma (HCC) is considered one of the greatest challenges to human life and is the most common form of liver cancer. Treatment of HCC depends on chemotherapy, radiotherapy, surgery, and immunotherapy, all of which have their own drawbacks, and patients may develop resistance to these therapies due to the aggressive behavior of HCC cells. New and effective therapies for HCC can be developed by targeting molecular signaling pathways. The expression of signal transducer and activator of transcription 3 (STAT3) in human cancer cells changes, and during cancer progression, the expression tends to increase. After induction of STAT3 signaling by growth factors and cytokines, STAT3 is phosphorylated and translocated to the nucleus to regulate cancer progression. The concept of the current review revolves around the expression and phosphorylation status of STAT3 in HCC, and studies show that the expression of STAT3 is high during the progression of HCC. This review addresses the function of STAT3 as an oncogenic factor in HCC, as STAT3 is able to prevent apoptosis and thus promote the progression of HCC. Moreover, STAT3 regulates both survival- and death-inducing autophagy in HCC and promotes cancer metastasis by inducing the epithelial-mesenchymal transition (EMT). In addition, upregulation of STAT3 is associated with the occurrence of chemoresistance and radioresistance in HCC. Specifically, non-protein-coding transcripts regulate STAT3 signaling in HCC, and their inhibition by antitumor agents may affect tumor progression. In this review, all these topics are discussed in detail to provide further insight into the role of STAT3 in tumorigenesis, treatment resistance, and pharmacological regulation of HCC.

Innate Lymphoid Cells: Emerging Players in Pancreatic Disease

Common pancreatic diseases have caused significant economic and social burdens worldwide. The interstitial microenvironment is involved in and plays a crucial part in the occurrence and progression of pancreatic diseases. Innate lymphoid cells (ILCs), an innate population of immune cells which have only gradually entered our visual field in the last 10 years, play an important role in maintaining tissue homeostasis, regulating metabolism, and participating in regeneration and repair. Recent evidence indicates that ILCs in the pancreas, as well as in other tissues, are also key players in pancreatic disease and health. Herein, we examined the possible functions of different ILC subsets in common pancreatic diseases, including diabetes mellitus, pancreatitis and pancreatic cancer, and discussed the potential practical implications of the relevant findings for future further treatment of these pancreatic diseases.

Role of Th22 Cells in Human Viral Diseases

Naive CD4⁺ T cells can differentiate into different cell subsets after receiving antigen stimulation, which secrete corresponding characteristic cytokines and thereby exert biological effects in various diseases. Th22 cells, a novel subset of CD4⁺ T cells, are different from Th1, Th2, Th17, and Treg cell subsets, which have been discovered in recent years. They can express CCR4, CCR6, and CCR10 molecules and secrete IL-22, IL-13, and TNF-α. They are not able to secrete IL-17, IL-4, and interferon-γ (IFN-γ). IL-22 is considered as a major effector molecule of Th22 cells whose functions and mechanisms of regulating cell differentiation have been constantly improved. In this review, we provide an overview of the origin, differentiation of Th22 cells. Moreover, we also describe the interrelationships between Th22 cells and Th17, Th1, and Th2 cells. Additionally, the role of Th22 cells were discussed in human diseases with virus infection, which will provide novel insight for the prevention and treatment of viral infection in human.

Inflammation-Induced Tumorigenesis and Metastasis

Inflammation, especially chronic inflammation, plays a pivotal role in tumorigenesis and metastasis through various mechanisms and is now recognized as a hallmark of cancer and an attractive therapeutic target in cancer. In this review, we discuss recent advances in molecular mechanisms of how inflammation promotes tumorigenesis and metastasis and suppresses anti-tumor immunity in various types of solid tumors, including esophageal, gastric, colorectal, liver, and pancreatic cancer as well as hematopoietic malignancies.

Targeted treatment of alcoholic liver disease based on inflammatory signalling pathways

Targeted therapy is an emerging treatment strategy for alcoholic liver disease (ALD). Inflammation plays an important role in the occurrence and development of ALD, and is a key choice for its targeted treatment, and anti-inflammatory treatment has been considered beneficial for liver disease. Surprisingly, immune checkpoint inhibitors have become important therapeutic agents for hepatocellular carcinoma (HCC). Moreover, studies have shown that the combination of inflammatory molecule inhibitors and immune checkpoint inhibitors can exert better effects than either alone in mouse models of HCC. This review discusses the mechanism of hepatic ethanol metabolism and the conditions under which inflammation occurs. In addition, we focus on the potential molecular targets in inflammatory signalling pathways and summarize the potential targeted inhibitors and immune checkpoint inhibitors, providing a theoretical basis for the targeted treatment of ALD and the development of new combination therapy strategies for HCC.

Interleukin 22 is related to development and poor prognosis of hepatocellular carcinoma

BACKGROUND AND AIMS

Immune response against hepatitis B virus (HBV) infection is an important risk factor for the development of hepatocellular carcinoma (HCC). Studies have reported that interleukin 22 (IL-22) exhibits both protective and pathological properties in liver diseases. Our aim was to explore the importance of IL-22 in the development of HCC, and to characterize the relationship between IL-22 levels and the prognosis of HCC.

METHODS

Totally, 136 liver biopsy specimens from 46 patients with chronic hepatitis B (CHB), 37 with atypical hyperplasia (AH), 53 with HCC, patient-matched tumors and peritumoral surgical specimens from 56 HCC patients included in the study. The expression of IL-22 and CD8 was evaluated by immunochemistry. Corresponding serum samples were collected from 30 CHB, 30 AH, and 30 HCC patients. IL-22 expression was determined by an enzyme linked immunosorbent assay.

RESULTS

Liver-infiltrating IL-22+ cells increased in a stepwise manner from CHB to AH and HCC (CHB vs. AH, P=0.002; AH vs. HCC, P=0.010), whereas a decreasing trend was observed for CD8+ T cells (CHB vs. AH, P=0.031; AH vs. HCC, P=0.652). Serum IL-22 levels also increased from CHB to AH and HCC (CHB vs. AH, P=0.024; AH vs. HCC, P=0.026). Tumor-infiltrating IL-22+ cells and serum IL-22 were associated with histologic grade (P=0.024 and P=0.033). Additionally, CD8+ T cells correlated with tumor size (P=0.032). Furthermore, the high intratumoral IL-22+ cell group and high serum IL-22 group showed lower overall survival (OS; P=0.001, P=0.017) and disease-free survival (DFS; P=0.005, P<0.001). Multivariate analysis revealed that intratumoral IL-22+ cells and serum IL-22 levels were independent prognostic factors for both OS and DFS.

CONCLUSIONS

These findings indicate that IL-22 promotes the progression of HCC in CHB patients. High tumor-infiltrating IL-22+ cells and serum IL-22 levels are thought to be unfavorable prognostic indicators for HCC.

ILC3 cells promote the proliferation and invasion of pancreatic cancer cells through IL-22/AKT signaling

PURPOSE

Type 3 innate lymphocytes (ILC3s) are reported to be involved in lung cancer, possibly by producing interleukin-22 (IL-22). However, whether ILC3s and their secreted IL-22 molecules contribute to the pathogenesis of pancreatic cancer (PC) remains unclear. To this end, in this study, we investigated the effects and possible mechanisms of ILC3s on PC pathogenesis.

METHOD

The IL-22 and IL-2i2R levels and the ILC3s' frequency in cancer tissues from PC patients and in peripheral blood from PC patients and healthy controls were analyzed by flow cytometry, immunochemistry, or immunofluorescence. The effects of IL-22-induced AKT signaling on the proliferation, invasion, and migration of PC cells were examined by co-culturing PC cell lines with ILC3s isolated from PC tissues, with or without the addition of neutralizing IL-22 antibody, IL-22R antibody or AKT inhibitor.

RESULTS

Our results showed that IL-22 and ILC3s were significantly upregulated in the PBMCs and cancer tissues of PC patients, and the IL-22R level was increased in PC cells. The increased frequency of ILC3s was positively correlated with the clinical features of PC patients. Co-culture experiments indicated that ILC3s promoted the proliferation, invasion, and migration of PC cell lines by secreting IL-22 to activate AKT signaling because IL-22/IL-22R or AKT blockage markedly counteracted such effects on PC cells.

CONCLUSION

Our data demonstrated that ILC3s may promote PC pathogenesis through IL-22/IL-22R-AKT signaling, suggesting a potential intervention target for PC treatment in the future.

Clinical immunology and immunotherapy for hepatocellular carcinoma: current progress and challenges

At the time of hepatocellular carcinoma (HCC) diagnosis, patients are most often at an advanced stage; however, the current treatment regimens remain unsatisfactory. Thus, novel and more powerful therapeutic approaches for advanced HCC are urgently required. Exacerbation of immunotolerant signals and/or escaping immunosurveillance leads to the development of HCC, which appears to be a rational reason to use immunotherapy to restore anticancer immunity. Several novel immunotherapeutic methods, including the use of immune checkpoint inhibitors, new types of immune cell adoption [e.g., chimeric antigen receptor T cell (CAR-T), TCR gene-modified T cells and stem cells], and microRNAs have been used in clinical trials for the treatment of HCC. However, some crucial issues remain to be addressed for such novel immunotherapy techniques. Finally, immunotherapy is now standing on the threshold of great advances in the fight against HCC.

Inflammatory cytokines and change of Th1/Th2 balance as prognostic indicators for hepatocellular carcinoma in patients treated with transarterial chemoembolization

Tumor-associated immune response plays a critical role in cancer pathogenesis. This study evaluated clinical implications of T cell cytokines and regulatory T cells (Tregs) in HCC patients treated with TACE. Whole blood was obtained for analysis of T cell cytokines (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-12p70, IL-13, IL-17A, IL-22, IFN-γ, and TNF-α) and Tregs from 142 HCC patients. Patients with CTP class A had a significantly lower proportion of detectable IL-4 or IL-6, but a higher proportion of detectable IL-22 than patients with CTP class B/C. IL-6 level was well correlated with tumor stage and undetectable IL-17A was associated with extrahepatic metastasis. The overall survival rate was significantly higher in patients who had undetectable IL-6 or detectable IL-22 than patients who did not. IL-6 among cytokines remained independently predictive factor for survival. Increased IFN-γ/IL-10 ratio and no increase in IL-6 level following TACE were associated with prolonged survival, and baseline Tregs could affect Th1/Th2 balance. T cell cytokines are associated with a variety of clinical aspects of HCC, and IL-6 is the most significant predictor of survival. A shift toward increased Th1 response and no increase in IL-6 level exert favorable immunologic effects on HCC prognosis.

Enhanced Regeneration and Hepatoprotective Effects of Interleukin 22 Fusion Protein on a Predamaged Liver Undergoing Partial Hepatectomy

Liver ischemia-reperfusion injury (IRI) and regeneration deficiency are two major challenges for surgery patients with chronic liver disease. As a survival factor for hepatocytes, interleukin 22 (IL-22) plays an important role in hepatoprotection and the promotion of regeneration after hepatectomy. In this study, we aim to investigate the roles of an interleukin 22 fusion protein (IL-22-FP) in mice with a predamaged liver after a two-third partial hepatectomy (PHx). Predamaged livers in mice were induced by concanavalin A (ConA)/carbon tetrachloride (CCl4) following PHx with or without IL-22-FP treatment. A hepatic IRI mouse model was also used to determine the hepatoprotective effects of IL-22-FP. In the ConA/CCl4 model, IL-22-FP treatment alleviated liver injury and accelerated hepatocyte proliferation. Administration of IL-22-FP activated the hepatic signal transducer and activator of transcription 3 (STAT3) and upregulated the expression of many mitogenic proteins. IL-22-FP treatment prior to IRI effectively reduced liver damage through decreased aminotransferase and improved liver histology. In conclusion, IL-22-FP promotes liver regeneration in mice with predamaged livers following PHx and alleviates IRI-induced liver injury. Our study suggests that IL-22-FP may represent a promising therapeutic drug against regeneration deficiency and liver IRI in patients who have undergone PHx.

Purinoceptor expression in hepatocellular virus (HCV)-induced and non-HCV hepatocellular carcinoma: an insight into the proviral role of the P2X4 receptor

The basic idea behind this study was to discover the association and prevalence of purinoceptors in hepatitis C virus (HCV) and non-HCV hepatocellular carcinoma (HCC). Immunohistochemistry was performed to study the expression of P2X4 and P2X7 receptors on ex-planted liver tissue samples that were collected from HCC patients. Antibodies specific for the P2X4 and P2X7 receptors were used to target the specific receptors and secondary antibody was used with 3,3'-diaminobenzidine (DAB) detection system to visualize the color change in case of any positive expression There was a substantial increase in P2X4 receptor expression in HCV induced HCC as compared to non-HCV HCC. Surprisingly, there was no increase in the P2X7 receptor expression in both HCV HCC and non-HCV HCC. We conclude that P2X4 receptor expression was significant in the presence of HCV HCC. This may confirms the potential role of P2X4 receptor in the presence of virus in liver pathology. However insignificant expression of P2X7 receptor may avert our attention towards understanding the role of this receptor in pro-inflammatory and immune responses.

The Interleukin-20 Cytokine Family in Liver Disease

The three main causes of inflammation and chronic injury in the liver are viral hepatitis, alcohol consumption, and non-alcoholic steatohepatitis, all of which can lead to liver fibrosis, cirrhosis, and hepatocellular carcinoma, which in turn may prompt the need for liver transplant. The interleukin (IL)-20 is a subfamily part of the IL-10 family of cytokines that helps the liver respond to damage and disease, they participate in the control of tissue homeostasis, and in the immunological responses developed in this organ. The best-studied member of the family in inflammatory balance of the liver is the IL-22 cytokine, which on the one hand may have a protective role in fibrosis progression but on the other may induce liver tissue susceptibility in hepatocellular carcinoma development. Other members of the family might also carry out this dual function, as some of them share IL receptor subunits and signal through common intracellular pathways. Investigators are starting to consider the potential for targeting IL-20 subfamily members in liver disease. The recently explored role of miRNA in the transcriptional regulation of IL-22 and IL-24 opens the door to promising new approaches for controlling the local immune response and limiting organ injury. The IL-20RA cytokine receptor has also been classified as being under miRNA control in non-alcoholic steatohepatitis. Moreover, researchers have proposed combining anti-inflammatory drugs with IL-22 as a hepatoprotective IL for alcoholic liver disease (ALD) treatment, and clinical trials of ILs for managing severe alcoholic-derived liver degeneration are ongoing. In this review, we focus on exploring the role of the IL-20 subfamily of cytokines in viral hepatitis, ALD, non-alcoholic steatohepatitis, and hepatocellular carcinoma, as well as delineating the main strategies explored so far in terms of therapeutic possibilities of the IL-20 subfamily of cytokines in liver disease.

Clostridium butyricum B1 alleviates high-fat diet-induced steatohepatitis in mice via enterohepatic immunoregulation

BACKGROUND AND AIM

Enterohepatic immunologic derangement is associated with non-alcoholic steatohepatitis. Here, we investigated whether Clostridium butyricum B1 (CB) would be an effective immune-targeted substance to attenuate steatohepatitis in mice.

METHODS

Thirty mice were randomized into a control group fed with common forage, a high-fat diet (HFD) group fed an HFD for 16 weeks, and an HFD + CB group treated with CB for the latter 8 weeks. Inflammation-associated or metabolism-associated genes in the liver or epididymal fat tissue were quantified; intrahepatic and intestinal immune factors were detected. Further short-chain fatty acids in the cecal contents or liver were measured, and differentiations of T cells in vitro were analyzed.

RESULTS

Characteristics of non-alcoholic steatohepatitis in the HFD group were obvious and were significantly attenuated in the HFD + CB group. The messenger RNA levels of monocyte chemotactic protein-1 and tumor necrosis factor-α in the liver and epididymal fat tissue were increased in the HFD group compared with the control group and were downregulated in the HFD + CB group. Intrahepatic and intestinal interferon-γ and interleukin (IL)-17 were significantly increased, whereas forkhead box P3, IL-4, and IL-22 were significantly decreased in the HFD group compared with the control group. However, these intrahepatic or intestinal immune changes were reversed after CB intervention. Furthermore, butyrate in the cecal content and liver of the HFD + CB group was significantly elevated. An in vitro investigation showed that sodium butyrate promoted CD4⁺ T cell differentiation into Th2, Th22, or Treg, whereas it inhibited CD4⁺ T cell differentiation into Th1 or Th17 under a cytokine milieu, which was mimicked by Trichostatin A.

CONCLUSION

Clostridium butyricum B1 could attenuate HFD-induced steatohepatitis in mice partially through butyrate-induced enterohepatic immunoregulation.

Toward cure chronic hepatitis B infection and hepatocellular carcinoma prevention: Lessons learned from nucleos(t)ide analogues therapy

Nucleos(t)ide analogues (NAs) could successfully suppress hepatitis B virus (HBV) replication in patients with chronic hepatitis B (CHB). However, due to probable development of drug resistance or low/delayed response, these treatments may not be satisfactory. In addition to the HBV DNA polymerase inhibiting activity, these drugs could lead to changes in cytokines profiles. It is important to monitor these changes so that they could be used as target of treatment. Evaluating the previously reported immune responses due to NAs treatments, it was concluded that interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin-4 (IL-4), and IL-12 increase after the treatment. This will be followed by the improved capacity of immune cells for eliminating HBV. In contrast, regulatory responses including IL-10 and transforming growth factor-beta (TGF-β) significantly decreased as the result of NAs therapy. Unexpectedly, T helper (Th) 17-associated cytokines also decreased significantly. These results could be used to employ the new strategies to suppress viral replication, minimize HBV DNA levels, inducing hepatitis B e antigen (HBeAg) seroconversion or even hepatitis B surface antigen (HBsAg) seroclearance. In order to accomplish these goals, extended treatment with high dose of both IL-12 and IFN in combination with high barrier to resistance NA might significantly improve the HBsAg seroclearance rate. Considering the danger of emerging aberrant immune responses, determining the optimum dosage as well as close monitoring of patients during the treatment is strongly advised. In order to make HBV immunotherapy practical, further studies are needed to confirm these results.

The role of T helper 17 cells in the pathogenesis of hepatitis B virus-related liver cirrhosis (Review)

In chronic hepatitis B virus (HBV)-infected patients, T helper 17 (Th17) cells are significantly elevated. Th17 cells initiate immune-mediated pathogenesis and have a critical role in the process of HBV-related liver cirrhosis (HBV-LC). The mechanisms underlying this process are attributed to Th17-secreted cytokines, which include interleukin (IL)-17, IL-21 and IL-22; however, a systemic analysis regarding these mechanisms has yet to be conducted. Therefore, the present study aimed to investigate the role of Th17 cells in the pathogenesis of HBV-LC. All randomized clinical trials, case series, case reports and meta-analyses that contained the aforementioned keywords were included in the review process. In addition, unpublished information from the Food and Drug Administration was included. The findings indicated that Th17-secreted cytokines, including IL-17, IL-21 and IL-22, function by activating or silencing hepatic stellate cells, modulating proinflammatory and pro- or antifibrogenic effectors, regulating extracellular matrix formation, upregulating chemokine expression, and inducing hepatocellular damage or hepatoprotection during the HBV-LC process. In addition, Th17 cells and Th17-secreted cytokines may be considered a potential tool in the diagnosis or treatment of HBV-LC. The present review summarized the role of Th17 cells in the pathogenesis of HBV-LC in order to deepen the clinical understanding of the role of Th17 cells and also to support the development of effective therapies for patients with HBV-LC.

Total fecal microbiota transplantation alleviates high-fat diet-induced steatohepatitis in mice via beneficial regulation of gut microbiota

Non-alcoholic steatohepatitis (NASH) is an epidemic metabolic disease with limited therapeutic strategies. Cumulative data support the pivotal role of gut microbiota in NASH. Here, we investigated the hypothesis regarding whether fecal microbiota transplantation (FMT) is effective in attenuating high-fat diet (HFD)-induced steatohepatitis in mice. Mice were randomized into control, HFD and HFD + FMT groups. After an 8-week HFD, FMT treatment was initiated and carried out for 8 weeks. The gut microbiota structure, butyrate concentrations of the cecal content, liver pathology and intrahepatic lipid and cytokines were examined. Our results showed that after FMT, the gut microbiota disturbance was corrected in HFD-fed mice with elevated abundances of the beneficial bacteria Christensenellaceae and Lactobacillus. FMT also increased butyrate concentrations of the cecal content and the intestinal tight junction protein ZO-1, resulting in relief of endotoxima in HFD-fed mice. Steatohepatitis was alleviated after FMT, as indicated by a significant decrease in intrahepatic lipid accumulation (reduced Oli-red staining, decreased intrahepatic triglyceride and cholesterol), intrahepatic pro-inflammatory cytokines, and the NAS score. Accordingly, intrahepatic IFN-γ and IL-17 were decreased, but Foxp3, IL-4 and IL-22 were increased after FMT intervention. These data indicate that FMT attenuated HFD-induced steatohepatitis in mice via a beneficial effect on the gut microbiota.