Significance of the balance between regulatory T (Treg) and T helper 17 (Th17) cells during hepatitis B virus related liver fibrosis

Therapeutic approaches and novel antifibrotic agents in renal fibrosis: A comprehensive review

Renal fibrosis (RF) is one of the underlying pathological conditions leading to progressive loss of renal function and end-stage renal disease (ESRD). Over the years, various therapeutic approaches have been explored to combat RF and prevent ESRD. Despite significant advances in understanding the underlying molecular mechanism(s), effective therapeutic interventions for RF are limited. Current therapeutic strategies primarily target these underlying mechanisms to halt or reverse fibrotic progression. Inhibition of transforming growth factor-β (TGF-β) signaling, a pivotal mediator of RF has emerged as a central strategy to manage RF. Small molecules, peptides, and monoclonal antibodies that target TGF-β receptors or downstream effectors have demonstrated potential in preclinical models. Modulating the renin-angiotensin system and targeting the endothelin system also provide established approaches for controlling fibrosis-related hemodynamic changes. Complementary to pharmacological strategies, lifestyle modifications, and dietary interventions contribute to holistic management. This comprehensive review aims to summarize the underlying mechanisms of RF and provide an overview of the therapeutic strategies and novel antifibrotic agents that hold promise in its treatment.

Fibrostenosing Crohn's Disease: Pathogenetic Mechanisms and New Therapeutic Horizons

Bowel strictures are well recognized as one of the most severe complications in Crohn's disease, with variable impacts on the prognosis and often needing surgical or endoscopic treatment. Distinguishing inflammatory strictures from fibrotic ones is of primary importance due to the different therapeutic approaches required. Indeed, to better understand the pathogenesis of fibrosis, it is crucial to investigate molecular processes involving genetic factors, cytokines, alteration of the intestinal barrier, and epithelial and endothelial damage, leading to an increase in extracellular matrix synthesis, which ultimately ends in fibrosis. In such a complex mechanism, the gut microbiota also seems to play a role. A better comprehension of molecular processes underlying bowel fibrosis, in addition to radiological and histopathological findings, has led to the identification of high-risk patients for personalized follow-up and testing of new therapies, primarily in preclinical models, targeting specific pathways involving Transforming Growth Factor-β, interleukins, extracellular matrix balance, and gut microbiota. Our review aims to summarize current evidence about molecular factors involved in intestinal fibrosis' pathogenesis, paving the way for potential diagnostic biomarkers or anti-fibrotic treatments for stricturing Crohn's disease.

The dual role of regulatory T cells in hepatitis B virus infection and related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a major contributor to cancer-related deaths worldwide. Hepatitis B virus (HBV) infection is a major etiologic factor leading to HCC. While there have been significant advancements in controlling HBV replication, achieving a complete cure for HBV-related HCC (HBV-HCC) remains an intricate challenge. HBV persistence is attributed to a myriad of mechanisms, encompassing both innate and adaptive immune responses. Regulatory T cells (Tregs) are pivotal in upholding immune tolerance and modulating excessive immune activation. During HBV infection, Tregs mediate specific T cell suppression, thereby contributing to both persistent infection and the mitigation of liver inflammatory responses. Studies have demonstrated an augmented expression of circulating and intrahepatic Tregs in HBV-HCC, which correlates with impaired CD8+ T cell function. Consequently, Tregs play a dual role in the context of HBV infection and the progression of HBV-HCC. In this comprehensive review, we discuss pertinent studies concerning Tregs in HBV infection, HBV-related cirrhosis and HCC. Furthermore, we summarize Treg responses to antiviral therapy and provide Treg-targeted therapies specific to HBV and HCC.

Immune regulation and therapeutic application of T regulatory cells in liver diseases

CD4+ CD25+ FOXP3+ T regulatory cells (Tregs) are a subset of the immunomodulatory cell population that can inhibit both innate and adaptive immunity by various regulatory mechanisms. In hepatic microenvironment, proliferation, plasticity, migration, and function of Tregs are interrelated to the remaining immune cells and their secreted cytokines and chemokines. In normal conditions, Tregs protect the liver from inflammatory and auto-immune responses, while disruption of this crosstalk between Tregs and other immune cells may result in the progression of chronic liver diseases and the development of hepatic malignancy. In this review, we analyze the deviance of this protective nature of Tregs in response to chronic inflammation and its involvement in inducing liver fibrosis, cirrhosis, and hepatocellular carcinoma. We will also provide a detailed emphasis on the relevance of Tregs as an effective immunotherapeutic option for autoimmune diseases, liver transplantation, and chronic liver diseases including liver cancer.

HMGB1/PTEN/PI3K axis participates in the peripheral immune cell differentiation in two representative TCM syndromes of chronic hepatitis B patients

Liver depression and spleen deficiency syndrome (LDSDS) and spleen-gastric damp-heat syndrome (SGDHS) are two major traditional Chinese medicine syndromes observed in chronic hepatitis B (CHB). Both syndromes exhibit significant differences in the pathogenesis and prognosis, and are closely related to the immune system. However, the underlying mechanisms are largely unknown. This study aimed to explore the immunoregulatory mechanisms of the two syndromes and promote the differentiation precision between the two syndromes. Thirty-six patients with CHB (18 LDSDS patients and 18 SGDHS patients) and 14 healthy controls were recruited into this study and blood was collected from all the subjects for testing. We studied the contents of T lymphocytes by flow cytometry and the expression levels of HMGB1/PTEN/PI3K axis proteins by enzyme-linked immunosorbent assay (Elisa). Protein-protein interaction (PPI) networks among HMGB1/PTEN/PI3K axis were constructed for functional enrichment. The correlations between T lymphocytes and proteins were analyzed by constructing multiple regression equations. The results revealed that the CD8+ T cells level in the two syndromes were lower than that in healthy controls, and the levels of Th17, Treg cells, and HMGB1, PI3K, PDK1, Akt were higher than those of the healthy controls (p < 0.05). Moreover, the levels of CD4+ T, Th17 cells, and HMGB1, PTEN, PI3K in LDSDS were higher than SGDHS (p < 0.05). PPI network indicated that HMGB1/PTEN/PI3K axis participated in T cell activation and liver pathology. Our results revealed that HMGB1/PTEN/PI3K axis may play an important role in regulating the formation of peripheral immune differences between the two syndromes. CD4+ T and Th17 are two representative immune cells that may serve as potential biological markers for LDSDS and SGDHS in CHB.

The roles of lncRNAs in Th17-associated diseases, with special focus on JAK/STAT signaling pathway

One of the most crucial T cell subsets in a variety of autoimmune and chronic inflammatory illnesses is T helper (Th) 17 cells. Th17 cells appear to have an essential role in the clearance of extracellular pathogens during infections. However, Th17 cells are also involved in inflammation and have been implicated in the pathogenesis of several autoimmune diseases and human inflammatory conditions. Due to the involvement of Th17 cells in the onset of Th17-associated diseases, understanding molecular mechanisms of Th17 cell functions may open the door to developing tailored therapies to address these difficult disorders. However, the molecular mechanisms governing Th17 differentiation in various diseases are still not well understood. The JAK/STAT signaling pathway plays a critical role in immune responses and has been linked to various aspects of Th17 cell differentiation and function. In this article, we conducted a comprehensive review of various molecular mechanisms (JAK/STAT, microRNAs, etc.), that can affect the differentiation of Th17 cells in various Th17-associated diseases.

Molecular mechanisms of long non-coding RNAs in differentiation of T Helper17 cells

T helper (Th) 17 cells are one of the most important T cell subsets in a number of autoimmune and chronic inflammatory diseases. During infections, Th17 cells appear to play an important role in the clearance of extracellular pathogens. Th17 cells, on the other hand, are engaged in inflammation and have been linked to the pathophysiology of a number of autoimmune illnesses and human inflammatory disorders. A diverse group of RNA molecules known as lncRNAs serve critical functions in gene expression regulation. They may interact with a wide range of molecules, including DNA, RNA, and proteins, and have a complex structure. LncRNAs, which have restricted or no protein-coding activity, are implicated in a number of illnesses due to their regulatory impact on a variety of biological processes such as cell proliferation, apoptosis, and differentiation. Several lncRNAs have been associated with Th7 cell development in the context of immune cell differentiation. In this article, we cover new studies on the involvement of lncRNAs in Th17 cell differentiation in a variety of disorders, including auto-immune diseases, malignancies, asthma, heart disease, and infections.

Hepatic inflammatory responses in liver fibrosis

Chronic liver diseases such as nonalcoholic fatty liver disease (NAFLD) or viral hepatitis are characterized by persistent inflammation and subsequent liver fibrosis. Liver fibrosis critically determines long-term morbidity (for example, cirrhosis or liver cancer) and mortality in NAFLD and nonalcoholic steatohepatitis (NASH). Inflammation represents the concerted response of various hepatic cell types to hepatocellular death and inflammatory signals, which are related to intrahepatic injury pathways or extrahepatic mediators from the gut-liver axis and the circulation. Single-cell technologies have revealed the heterogeneity of immune cell activation concerning disease states and the spatial organization within the liver, including resident and recruited macrophages, neutrophils as mediators of tissue repair, auto-aggressive features of T cells as well as various innate lymphoid cell and unconventional T cell populations. Inflammatory responses drive the activation of hepatic stellate cells (HSCs), and HSC subsets, in turn, modulate immune mechanisms via chemokines and cytokines or transdifferentiate into matrix-producing myofibroblasts. Current advances in understanding the pathogenesis of inflammation and fibrosis in the liver, mainly focused on NAFLD or NASH owing to the high unmet medical need, have led to the identification of several therapeutic targets. In this Review, we summarize the inflammatory mediators and cells in the diseased liver, fibrogenic pathways and their therapeutic implications.

Knockout of Sema4D alleviates liver fibrosis by suppressing AOX1 expression

Liver fibrosis can occur in many chronic liver diseases, and no effective treatments are available due to the poorly characterized molecular pathogenesis. Semaphorin 4D (Sema4D) has immune functions and serves important roles in T cell priming. Here, we found that Sema4D was highly expressed in fibrotic liver, and the expression of Sema4D increased with hepatic stellate cells (HSCs) activation. Knockout of Sema4D alleviated liver fibrosis. Mechanistically, knockout of Sema4D alleviated liver fibrosis by suppressing the expression of AOX1 in retinol metabolism. Further investigation demonstrated that retinoic acid receptor α (RARA), an important nuclear receptor of retinoic acid, was reduced by Sema4D knockout during liver fibrogenesis. Sema4D knockout-mediated suppression of liver fibrosis was partly mediated by regulating the balance of Th1, Th2, Th17, and T-bet+Treg cells via inhibiting AOX1/RARA. Thus, targeting Sema4D may hold promise as a potential therapeutic approach for treating liver fibrosis.

Mechanisms of organ fibrosis: Emerging concepts and implications for novel treatment strategies

Fibrosis, or tissue scarring, develops as a pathological deviation from the physiological wound healing response and can occur in various organs such as the heart, lung, liver, kidney, skin, and bone marrow. Organ fibrosis significantly contributes to global morbidity and mortality. A broad spectrum of etiologies can cause fibrosis, including acute and chronic ischemia, hypertension, chronic viral infection (e.g., viral hepatitis), environmental exposure (e.g., pneumoconiosis, alcohol, nutrition, smoking) and genetic diseases (e.g., cystic fibrosis, alpha-1-antitrypsin deficiency). Common mechanisms across organs and disease etiologies involve a sustained injury to parenchymal cells that triggers a wound healing response, which becomes deregulated in the disease process. A transformation of resting fibroblasts into myofibroblasts with excessive extracellular matrix production constitutes the hallmark of disease, however, multiple other cell types such as immune cells, predominantly monocytes/macrophages, endothelial cells, and parenchymal cells form a complex network of profibrotic cellular crosstalk. Across organs, leading mediators include growth factors like transforming growth factor-β and platelet-derived growth factor, cytokines like interleukin-10, interleukin-13, interleukin-17, and danger-associated molecular patterns. More recently, insights into fibrosis regression and resolution of chronic conditions have deepened our understanding of beneficial, protective effects of immune cells, soluble mediators and intracellular signaling. Further in-depth insights into the mechanisms of fibrogenesis can provide the rationale for therapeutic interventions and the development of targeted antifibrotic agents. This review gives insight into shared responses and cellular mechanisms across organs and etiologies, aiming to paint a comprehensive picture of fibrotic diseases in both experimental settings and in human pathology.

Regulatory T cells (Tregs) in liver fibrosis

The ability of the human liver to both synthesize extracellular matrix(ECM), as well as regulate fibrogenesis, are integral functions to maintaining homoeostasis. Chronic liver injury stimulates fibrogenesis in response to the imbalance between ECM accumulation and fibrosis resolution. Liver disease that induces fibrogenesis is associated with multiple risk factors like hepatitis infection, schistosomiasis, alcohol, certain drugs, toxicants and emerging aetiology like diabetes and obesity. The activation of hepatic stellate cells (HSCs), whose function is to generate and accumulate ECM, is a pivotal event in liver fibrosis. Simultaneously, HSCs selectively promote regulatory T-cells (Tregs) in an interleukin-2-dependent pattern that displays a dual relationship. On the one hand, Tregs can protect HSCs from NK cell attack, while on the other hand, they demonstrate an inhibitory effect on HSCs. This paper reviews the dual role of Tregs in liver fibrogenesis which includes its promotion of immunosuppression, as well as its activation of fibrosis. In particular, the balance between Tregs and the Th17 cell population, which produce interleukin (IL)-17 and IL-22, is explored to demonstrate their key role in maintaining homoeostasis and immunoregulation. The contradictory roles of Tregs in liver fibrosis in different immune microenvironments and molecular pathways need to be better understood if they are to be deployed to manage this disease.

Alterations in gut microbiome and metabolomics in chronic hepatitis B infection-associated liver disease and their impact on peripheral immune response

Gut dysbiosis has been reported in chronic hepatitis B (CHB) infection, however its role in CHB progression and antiviral treatment remains to be clarified. Herein, the present study aimed to characterize gut microbiota (GM) in patients with chronic hepatitis B virus infection-associated liver diseases (HBV-CLD) by combining microbiome with metabolome analyses and to evaluate their effects on peripheral immunity. Fecal samples from HBV-CLD patients (n = 64) and healthy controls (n = 17) were collected for 16s rRNA sequencing. Fecal metabolomics was measured with untargeted liquid chromatography-mass spectrometry in subgroups of 58 subjects. Lineage changes of peripheral blood mononuclear cells (PBMCs) were determined upon exposure to bacterial extracts (BE) from HBV-CLD patients. Integrated analyses of microbiome with metabolome revealed a remarkable shift of gut microbiota and metabolites in HBV-CLD patients, and disease progression and antiviral treatment were found to be two main contributing factors for the shift. Concordant decreases in Turicibacter with 4-hydroxyretinoic acid were detected to be inversely correlated with serum AST levels through host-microbiota-metabolite interaction analysis in cirrhotic patients. Moreover, depletion of E.hallii group with elevated choline was restored in patients with 5-year antiviral treatment. PBMC exposure to BE from non-cirrhotic patients enhanced expansion of T helper 17 cells; however, BE from cirrhotics attenuated T helper 1 cell count. CHB progression and antiviral treatment are two main factors contributing to the compositional shift in microbiome and metabolome of HBV-CLD patients. Peripheral immunity might be an intermediate link in gut microbe-host interplay underlying CHB pathogenesis.

Hepatitis B functional cure and immune response

Hepatitis B virus (HBV) is a hepatotropic virus, which damage to hepatocytes is not direct, but through the immune system. HBV specific CD4⁺ T cells can induce HBV specific B cells and CD8⁺ T cells. HBV specific B cells produce antibodies to control HBV infection, while HBV specific CD8⁺ T cells destroy infected hepatocytes. One of the reasons for the chronicity of HBV infection is that it cannot effectively activate adoptive immunity and the function of virus specific immune cells is exhausted. Among them, virus antigens (including HBV surface antigen, e antigen, core antigen, etc.) can inhibit the function of immune cells and induce immune tolerance. Long term nucleos(t)ide analogues (NAs) treatment and inactive HBsAg carriers with low HBsAg level may "wake up" immune cells with abnormal function due to the decrease of viral antigen level in blood and liver, and the specific immune function of HBV will recover to a certain extent, thus becoming the "dominant population" for functional cure. In turn, the functional cure will further promote the recovery of HBV specific immune function, which is also the theoretical basis for complete cure of hepatitis B. In the future, the complete cure of chronic HBV infection must be the combination of three drugs: inhibiting virus replication, reducing surface antigen levels and specific immune regulation, among which specific immunotherapy is indispensable. Here we review the relationship, mechanism and clinical significance between the cure of hepatitis B and immune system.

Comparing the efficacy and safety of tenofovir and adefovir or combined drug treatment for the treatment of chronic hepatitis B infection: a systematic review and meta-analysis

BACKGROUND

Chronic hepatitis B (CHB) affects a vast population globally. A variety of drugs are available for the treatment of CHB, including tenofovir (TDF) and adefovir (ADV). However, the efficacy of monotherapy drug treatment is inconclusive, the safety and efficacy of TDF remain unclear, more data are needed to be included and combined drug treatment is considered to exhibit higher efficacy. To explore this issue, we performed a current literature review and meta-analysis to compare the efficacy and safety of ADV vs. TDF, TDF vs. ADV + lamivudine (LAM); TDF vs. ADV + entecavir (ETV).

METHODS

We systematically searched China National Knowledge Infrastructure, the Cochrane Library, Embase, PubMed, Chinese VIP, and Wanfang Data, for relevant clinical trials since July 2015, all included studies were based on PICOS principles and evaluated independently by the reviewers in accordance with the Cochrane Handbook (Rob2.0). A meta-analysis was performed by using Review Manager 5.4.

RESULTS

We included a total of 32 studies, including 31 randomized controlled trials and one retrospective study involving 2,473 patients. The results revealed a low risk of bias in included studies, that the virologic response of TDF was superior to ADV (P<0.05). And TDF was also superior to ADV in Serum creatinine levels, Immunologic function, and safety profile. However, when ADV was combined with other medications, it was superior to TDF in alanine aminotransferase (ALT) level and Tbil level and adverse reactions, but on other indicators, TDF was superior to drug combination therapy.

CONCLUSIONS

Results showed that TDF was superior to ADV in the parameters of ALT, hepatitis B virus (HBV)-DNA reduction, HBeAg-negative conversion rate, safety, and total bilirubin levels in patients with CHB. However, when ADV was combined with LAM or ETV, they often showed the same therapeutic effect as TDF in parameters such as ALT level and Tbil level and combined therapy can effectively reduce the occurrence of adverse reactions. In this study, because the sample source countries were limited, a greater number of global studies are needed in the future to verify the current findings.

Double-Negative T Cells Regulate Hepatic Stellate Cell Activation to Promote Liver Fibrosis Progression via NLRP3

Aim

We mainly explored the role and mechanism of double-negative T cells (DNTs) in liver fibrosis.

Methods

DNTs were co-cultured with mouse hepatic stellate cells (HSCs). Later, cell viability was detected by Cell Counting Kit-8 (CCK-8) assay; α-SMA expression was measured through fluorescence staining; TNF-α, IL-6, and MMP-9 levels were measured by ELISA; and the expression of Bcl-2, TGF-β1, NLRP3, ASC, and TNFR1 proteins in HSCs was detected by Western blotting (WB) assay. At the same time, HSC-NLRP3-/- and HSC-TNFR1-/- are used to explore the mechanism. In mouse experiments, mice were intraperitoneally injected with DNTs; afterward, the hepatic tissue fibrosis degree was detected by Masson staining, α-SMA expression was measured through immunohistochemistry (IHC) assay, and histopathological changes were detected by sirius-red staining and H&E staining.

Results

The results suggested that DNTs promoted HSC activation and NLRP3 activation. The effect of DNTs on activating HSC-NLRP3-/- was suppressed, and the difference was significant as compared with HSCs. HSC-TNFR1-/- activation was also inhibited. To explore the mechanism of DNT-secreted TNF-α in TNFR1-NLRP3 activation, we transfected DNTs with TNF-α siRNA; as a result, DNTs with TNF-α silencing did not significantly affect HSC activation. DNTs promoted hepatic tissue fibrosis progression and HSC activation; after treatment with NLRP3 inhibitor, the effect of DNTs on promoting fibrosis was suppressed.

Conclusion

We discovered that DNTs played an important role in liver fibrosis and that DNTs promoted HSC activation via the TNF-α-TNFR1-NLRP3 signal axis, thus further promoting liver fibrosis progression.

Interleukin-17-A multifaceted cytokine in viral infections

Viral infections are a major threat to the human population due to the lack of selective therapeutic measures. The morbidity and mortality reported worldwide are very alarming against viral pathogens. The proinflammatory environment is required for viral inhibition by initiating the host immune response. The host immune response fights these pathogens by secreting different cytokines. Interleukin-17 (IL-17) a proinflammatory cytokine mainly produced by T helper type 17 cells, plays a vital role in the regulation of host immune response against various pathogens, including viruses. However, dysregulated production of IL-17 induces chronic inflammation, autoimmune disorders, and may lead to cancer. Recent studies suggest that IL-17 is not only involved in the antiviral immune response but also promotes virus-mediated illnesses. In this review, we discuss the protective and pathogenic role of IL-17 against various viral infections. A detailed understanding of IL-17 during viral infections could contribute to improve therapeutic measures and enable the development of an efficient and safe IL-17 based immunotherapy.

IFN-γ facilitates liver fibrogenesis by CD161+CD4+ T cells through a regenerative IL-23/IL-17 axis in chronic hepatitis B virus infection

Objectives

This study aimed to determine the role of CD161⁺CD4⁺ T cells in chronic hepatitis B virus (HBV) infection.

Methods

A total of 94 patients with chronic hepatitis B (CHB), 73 with liver cirrhosis (LC) and 28 healthy controls were enrolled to determine frequency, cytokine production and chemokine receptor expression of circulating CD161⁺CD4⁺ T cells. Among these, 50 CHB and 34 LC patients were followed up for a period of 52‐week entecavir monotherapy to assess the association of CD161⁺CD4⁺ T cells with seroconversion of HBV e antigen (HBeAg). In addition, 15 patients with hepatocellular carcinoma (HCC) and 15 with hepatic haemangioma (HHA) were enrolled to compare the paired circulating and intrahepatic CD161⁺CD4⁺ T cells.

Results

CD161⁺CD4⁺ T cells were found to accumulate in the circulation of HBV cohorts, which showed a significant correlation with the clinical parameters of disease progression. In addition, higher numbers of circulating CD161⁺CD4⁺ T cells were associated with an improved serological response of HBeAg to antiviral treatment. Moreover, CD161⁺CD4⁺ T cells as compared to homologous CD161^‐CD4⁺ T cells produced more pro‐inflammatory cytokines including interleukin (IL)‐17 and interferon (IFN)‐γ and expressed higher levels of liver‐homing chemokine receptors including CCR6, CXCR6 and CX3CR1. Notably, a significant enrichment of CD161⁺CD4⁺ T cell subsets co‐expressing IFN‐γ and IL‐17 was observed in HBV‐associated cirrhotic livers. During in vitro co‐cultures, circulating CD161⁺CD4⁺ T cells in the chronic HBV setting exhibited prominent pro‐fibrogenic effects by regulating primary hepatic stellate cells through a regenerative IFN‐γ/IL‐23/IL‐17 axis.

Conclusions

In chronic HBV infection, CD161⁺CD4⁺ T cells play antiviral, pro‐inflammatory and pro‐fibrogenic roles.

Properties of macrophages and lymphocytes appearing in rat renal fibrosis followed by repeated injection of cisplatin

Properties of macrophages and lymphocytes appearing in renal fibrosis remains to be investigated. F344 rats were injected once a week with cisplatin (2 mg/kg body weight) for 8 weeks and examined at post-final injection weeks 1, 3, 6, 9, and 12. Rats developed progressive renal fibrosis at weeks 1 to 6 as fibrosis-progress phase, and subsequent amelioration at weeks 9 and 12. CD68+ M1-macrophages and major histocompatibility complex (MHC) class II+ macrophages remarkably increased persistently, whereas CD163+ M2-macrophages slightly increased. MHC class II+/CD68+ and MHC class II+/CD163+ macrophages were present, indicating that MHC class II+ macrophages might have both functions of M1- and M2-macrophages. In the fibrosis-progress phase, interleukin (IL)-6, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ for M1-factors, and transforming growth factor (TGF)-β1 and IL-10 for M2-factors tended to increase; tissue injury by M1 and fibrosis by M2 might have occurred simultaneously. Lots of CD4+ and CD8+ T cells appeared in close relation with MHC class II+ macrophages, and mainly CD4+ T cells formed aggregations. In the lymphocyte aggregates collected by laser microdissection, expression of IL-17A (for Th17 cells) and forkhead box P3 (FoxP3) (for Treg) significantly increased at weeks 1 and 6, respectively; presumably, Th17 cells might be involved in tissue injury, whereas Treg might be related to fibrosis amelioration. These results suggested that macrophages and T cells may contribute interrelatedly to renal fibrosis.

Complement Component C3: A Novel Biomarker Participating in the Pathogenesis of Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is currently the most common cause of chronic liver disorder worldwide. The pathological spectrum of NAFLD ranges from simple steatosis to non-alcoholic steatohepatitis (NASH) that induces progressive liver cirrhosis and eventually hepatocellular carcinoma (HCC). However, the molecular mechanisms driving the transformation of NASH are obscure. There is a compelling need for understanding the pathogenic mechanisms of NASH, and thereby providing new insight into mechanism-based therapy. Currently, several studies reported that complement system, an innate immune system, played an important role in the pathogenesis of NAFLD, which was also proved by our recent study. Complement component 3 (C3), a protein of the innate immune system, plays a hub role in the complement system. Herein, we present a review on the role and molecular mechanism of C3 in NASH as well as its implication in NASH diagnosis and treatment.

Novel Immune Subsets and Related Cytokines: Emerging Players in the Progression of Liver Fibrosis

Liver fibrosis is a pathological process caused by persistent chronic injury of the liver. Kupffer cells, natural killer (NK) cells, NKT cells, and dendritic cells (DCs), which are in close contact with T and B cells, serve to bridge innate and adaptive immunity in the liver. Meanwhile, an imbalanced inflammatory response constitutes a challenge in liver disease. The dichotomous roles of novel immune cells, including T helper 17 (Th17), regulatory T cells (Tregs), mucosa-associated invariant T cells (MAIT), and innate lymphoid cells (ILCs) in liver fibrosis have gradually been revealed. These cells not only induce damage during liver fibrosis but also promote tissue repair. Hence, immune cells have unique, and often opposing, roles during the various stages of fibrosis. Due to this heterogeneity, the treatment, or reversal of fibrosis through the target of immune cells have attracted much attention. Moreover, activation of hepatic stellate cells (HSCs) constitutes the core of fibrosis. This activation is regulated by various immune mediators, including Th17, Th22, and Th9, MAIT, ILCs, and γδ T cells, as well as their related cytokines. Thus, liver fibrosis results from the complex interaction of these immune mediators, thereby complicating the ability to elucidate the mechanisms of action elicited by each cell type. Future developments in biotechnology will certainly aid in this feat to inform the design of novel therapeutic targets. Therefore, the aim of this review was to summarize the role of specific immune cells in liver fibrosis, as well as biomarkers and treatment methods related to these cells.

Skewed Th17/Treg balance during progression and malignant transformation of oral submucous fibrosis

OBJECTIVES

The aim of our study was to determine the impact of Th17/Treg imbalance on the progression and malignant transformation of oral submucosal fibrosis (OSF).

MATERIALS AND METHODS

To assess Th17 and Treg expression, overall 52 peripheral blood samples from OSF, oral squamous cell carcinoma (OSCC) patients, and healthy donors were analyzed by flow cytometry. Thirty normal oral mucosa, 72 OSF, and 90 OSCC samples were analyzed by immunohistochemistry.

RESULTS

In peripheral blood samples, in OSCC with OSF, Th17 and Treg expression were significantly higher than those in OSF and OSCC without OSF as confirmed by immunohistochemistry. During OSF progression, Th17 and Th17/Treg ratio showed an increasing trend, while Treg expression showed a decreasing trend. Treg expression was significantly higher in OSCC with OSF than in OSF and OSCC without OSF, whereas the Th17/Treg ratio was significantly lower in OSCC with OSF. Treg expression was significantly correlated with smoking and clinical stage. Th17/Treg ratio was significantly associated with tumor size, lymph node metastasis, and clinical stage. A low Th17/Treg ratio was significantly associated with poor prognosis.

CONCLUSIONS

Th17/Treg ratio is a potential diagnostic indicator for OSF occurrence and malignant transformation and was an independent prognostic factor for OSCC.

Secreted factors from dental pulp stem cells improve Sjögren's syndrome via regulatory T cell-mediated immunosuppression

Background

Sjögren’s syndrome (SS) is a chronic autoimmune disease primarily characterized by inflammation in the salivary and lacrimal glands. Activated T cells contribute to disease pathogenesis by producing proinflammatory cytokines, which leads to a positive feedback loop establishment. The study aimed to evaluate the effects of secreted factors derived from dental pulp stem cells (DPSCs) or bone marrow mesenchymal stem cells (BMMSCs) on hyposalivation in SS and to investigate the mechanism involved.

Methods

Eighty percent confluent stem cells were replenished with serum-free Dulbecco’s modified Eagle’s medium and incubated for 48 h; following which, conditioned media from DPSCs (DPSC-CM) and BMMSCs (BMMSC-CM) were collected. Cytokine array analysis was performed to assess the types of cytokines present in the media. Flow cytometric analysis was performed to evaluate the number of activated T cells cultured in DPSC-CM or BMMSC-CM. Subsequently, DPSC-CM or BMMSC-CM was administered to an SS mouse model. The mice were categorized into the following groups (n = 6 each): non-treatment, Dulbecco’s modified Eagle’s medium (−), BMMSC-CM, and DPSC-CM. Histological analysis of the salivary glands was performed. The gene and protein expression levels of cytokines associated with T helper subsets in the submandibular glands (SMGs) were evaluated.

Results

DPSC-CM contained more secreted factors with tissue-regenerating mechanisms, such as cell proliferation, anti-inflammatory effects, and immunomodulatory effects. DPSC-CM was more effective in suppressing the activated T cells than other groups in the flow cytometric analysis. The stimulated salivary flow rate increased in SS mice with DPSC-CM compared with that in the other groups. In addition, the number of inflammation sites in SMGs of the mice administered with DPSC-CM was lower than that in the other groups. The expression levels of interleukin (Il)-10 and transforming growth factor-β1 were upregulated in the DPSC-CM group, whereas those of Il-4 and Il-17a were downregulated. The DPSC-CM-administered group presented with a significantly increased percentage of regulatory T (Treg) cells and a significantly decreased percentage of type 17 Th (Th17) cells compared with the other groups.

Conclusions

These results indicated that DPSC-CM ameliorated SS by promoting Treg cell differentiation and inhibiting Th17 cell differentiation in the mouse spleen.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02236-6.

The role of Th17 cells in viral infections

The present review provides an overview of recent advances regarding the function of Th17 cells and their produced cytokines in the progression of viral diseases. Viral infections alone do not lead to virus-induced malignancies, as both genetic and host safety factors are also involved in the occurrence of malignancies. Acquired immune responses, through the differentiation of Th17 cells, form the novel components of the Th17 cell pathway when reacting with viral infections all the way from the beginning to its final stages. As a result, instead of inducing the right immune responses, these events lead to the suppression of the immune system. In fact, the responses from Th17 cells during persistent viral infections causes chronic inflammation through the production of IL-17 and other cytokines which provide a favorable environment for tumor growth and its development. Additionally, during the past decade, these cells have been understood to be involved in tumor progression and metastasis. However, further research is required to understand Th17 cells' immune mechanisms in the vast variety of viral diseases. This review aims to determine the roles and effects of the immune system, especially Th17 cells, in the progression of viral diseases; which can be highly beneficial for the diagnosis and treatment of these infections.

An insight into the mechanism and molecular basis of dysfunctional immune response involved in cholestasis

Cholestasis is one of the most common clinical symptom of liver diseases. If patients do not receive effective treatment, cholestasis can evolve into liver fibrosis, cirrhosis and ultimately liver failure requiring liver transplantation. Currently, only ursodeoxycholic acid, obeticholic acid and bezafibrate are FDA-approved drugs, thereby requiring a breakthrough in new mechanisms and therapeutic development. Inflammation is one of the common complications of cholestasis. Hepatic accumulation of toxic hydrophobic bile acids is a highly immunogenic process involving both resident and immigrating immune cells. And the resulting inflammation may further aggravate hepatocyte injury. Though, great investigations have been made in the immune responses during cholestasis, the relationship between immune responses and cholestasis remains unclear. Moreover, scarce reviews summarize the immune responses during cholestasis and the efficacy of therapies on immune response. The main purpose of this paper is to review the existing literature on dysfunctional immune response during cholestasis and the effect of treatment on immune response which may provide an insight for researchers and drug development.

Serum Interleukin-35 Level in Correlation with T Regulatory and T helper-17 Cells Frequency in Chronic Viral Hepatitis C Patients

Interleukin-35 (IL-35), secreted mainly by T-regulatory cells (T-regs), has been considered to have immunosuppressive actions in many auto-immune diseases and tumors. However, information about its role in chronic hepatitis C (CHC) infection is still limited. We aimed to study the role of IL-35 within CHC infection and to assess its correlation with T-regs and T-helper 17 cells (Th-17). Therefore, we measured serum IL-35 concentrations using ELISA assay in 25 normal controls (NCs) and in 30 CHC patients before receiving direct antiviral agents (DAA) treatment and after 3 months of treatment end. T-regs and Th-17 cells frequencies were assessed via flow-cytometry in control group and patients’ group before treatment. The results showed that serum IL-35 levels revealed a highly significant increase in CHC patients compared to NCs (P <0.001). Moreover, IL-35 levels significantly decreased in patients 3 months after treatment end (P =0.02). Both Th-17 and T-regs were significantly increased in patients more than in NCs and a positive correlation was observed between them. However, T-regs/Th-17 ratio did not show significant difference from the ratio in NCs. IL-35 levels were positively correlated with viral load and T-regs frequency, but not with Th-17 frequency. IL-35 levels did not correlate with liver enzymes or functions. These results suggested that IL-35 enhances the immunosuppressive functions of T-regs, protecting the liver from HCV induced damage and contributes to viral persistence. IL-35 may represent a possible immunotherapeutic strategy for chronic persistent infection if given with DAA, especially in relapsing or non-responding cases.

Intrahepatic TH17/TReg Cells in Homeostasis and Disease-It's All About the Balance

Both acute and chronic hepatic inflammation likely result from an imbalance in the T_H1/T_H2 cell response and can lead to liver fibrosis and end-stage liver disease. More recently, a novel CD4+ T helper cell subset was described, characterized by the production of IL-17 and IL-22. These T_H17 cells 50were predominantly implicated in host defense against infections and in autoimmune diseases. Interestingly, studies over the last 10 years revealed that the development of T_H17 cells favors pro-inflammatory responses in almost all tissues and there is a reciprocal relationship between T_H17 and T_Reg cells. The balance between T_H17and T_Reg cells is critical for immune reactions, especially in injured liver tissue and the return to immune homeostasis. The pathogenic contribution of T_H17 and T_Reg cells in autoimmunity, acute infection, and chronic liver injury is diverse and varies among disease etiologies. Understanding the mechanisms underlying T_H17 cell development, recruitment, and maintenance, along with the suppression of T_Reg cells, will inform the development of new therapeutic strategies in liver diseases. Active manipulation of the balance between pathogenic and regulatory processes in the liver may assist in the restoration of homeostasis, especially in hepatic inflammation.

Dendritic Cell and T Cell Crosstalk in Liver Fibrogenesis and Hepatocarcinogenesis: Implications for Prevention and Therapy of Liver Cancer

Liver fibrosis is a chronic, highly prevalent disease that may progress to cirrhosis and substantially increases the risk for development of hepatocellular carcinoma (HCC). Fibrotic livers are characterized by an inflammatory microenvironment that is composed of various immunologically active cells, including liver-resident populations (e.g., Kupffer cells, hepatic stellate cells and sinusoidal endothelium) and infiltrating leukocytes (e.g., monocytes, monocyte-derived macrophages, neutrophils and lymphocytes). While inflammatory injury drives both fibrogenesis and carcinogenesis, the tolerogenic microenvironment of the liver conveys immunosuppressive effects that encourage tumor growth. An insufficient crosstalk between dendritic cells (DCs), the professional antigen presenting cells, and T cells, the efficient anti-tumor effector cells, is one of the main mechanisms of HCC tumor tolerance. The meticulous analysis of patient samples and mouse models of fibrosis-HCC provided in-depth insights into molecular mechanisms of immune interactions in liver cancer. The therapeutic modulation of this multifaceted immunological response, e.g., by inhibiting immune checkpoint molecules, in situ vaccination, oncolytic viruses or combinations thereof, is a rapidly evolving field that holds the potential to improve the outcome of patients with HCC. This review aims to highlight the current understanding of DC–T cell interactions in fibrogenesis and hepatocarcinogenesis and to illustrate the potentials and pitfalls of therapeutic clinical translation.

Sja-miR-71a in Schistosome egg-derived extracellular vesicles suppresses liver fibrosis caused by schistosomiasis via targeting semaphorin 4D

Schistosomiasis is characterized by liver fibrosis, and studies have indicated that Schistosoma japonicum (S. japonicum) eggs can limit the progression of liver fibrosis. However, the detailed molecular mechanisms are yet unclear. Extracellular vesicles (EVs) contain a selection of miRNAs for long-distance exchange of information and act as an important pathway for host-parasite communication. This study aimed to explore the potential role of S. japonicum egg-derived EVs and its key miRNA in liver fibrosis. Herein, we found that S. japonicum egg-derived EVs can inhibit the activation of hepatic stellate cells, which is mediated via the high expression of Sja-miR-71a. Sja-miR-71a in EVs attenuates the pathological progression and liver fibrosis in S. japonicum infection. Sja-miR-71a inhibiting TGF-β1/SMAD and interleukin (IL)-13/STAT6 pathways via directly targeting semaphorin 4D (Sema4D). In addition, Sja-miR-71a can also suppress liver fibrosis by regulating Th1/Th2/Th17 and Treg balance. This study contributes to further understanding of the molecular mechanisms underlying Schistosoma-host interactions, and Sema4D may be a potential target for schistosomiasis liver fibrosis treatment.

Regulatory T cells and T helper 17 cells in viral infection

CD4⁺ T cells are the central element of the adaptive immune responses and protect the body from a variety of pathogens. Starting from naive cells, CD4⁺ T cells can differentiate into various effector cell subsets with specialized functions including T helper (Th) 1, Th2, Th17, regulatory T (Treg) and T follicular helper (Tfh) cells. Among them, Tregs and Th17 cells show a strong plasticity allowing the functional adaptation to various physiological and pathological environments during immune responses. Although they are derived from the same precursor cells and their differentiation pathways are interrelated, the terminally differentiated cells have totally opposite functions. Studies have shown that Tregs and Th17 cells have rather complex interplays in viral infection: Th17 cells may contribute to immune activation and disease progression while Tregs may inhibit this process and play a key role in the maintenance of immune homoeostasis, possibly at the cost of compromised viral control. In this review, we take respiratory syncytial virus (RSV), hepatitis B virus (HBV)/hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections as examples to discuss these interplays and their impacts on disease progression in viral infection.

The JAK inhibitor tofacitinib ameliorates immune‑mediated liver injury in mice

The prevalence of immune-mediated liver diseases such as autoimmune liver disease or viral hepatitis has increased in recent years, and the side effects of pre-existing treatments are a worldwide problem. Regulatory T cells (Tregs) and T helper 17 (Th17) cells play important roles in the development of immune-mediated hepatitis and may serve as potential therapeutic targets. Tofacitinib, a new Janus kinase (JAK) inhibitor, is under investigation for the treatment of rheumatoid arthritis; it is also helpful in treating ulcerative colitis and psoriasis. The roles of tofacitinib were investigated in conferring protection against immune-mediated liver injury in mice. T cell-mediated hepatitis was induced by concanavalin A (ConA). The mice in the treatment groups were administered with tofacitinib intragastrically before the ConA injection. Histopathological examination was performed by hematoxylin and eosin (H&E) staining, and the serum transaminase and inflammatory cytokine levels were determined using an automatic biochemistry analysis apparatus or cytometric bead array (CBA) kits. Flow cytometric analysis was used to detect Tregs and Th17 cells. Tofacitinib significantly decreased the hepatic injury induced by ConA and prominently decreased the liver transaminase level. The secretion of several anti-inflammatory cytokines such as interleukin (IL)-10 was upregulated in mice from the treatment group, compared to that in mice treated with ConA alone, while the expression of interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) decreased. Tofacitinib treatment increased the number of Tregs and reduced the number of Th17 cells. Furthermore, tofacitinib could relieve liver fibrosis under conditions of autoimmune hepatitis (AIH). The present results indicated that tofacitinib improved immune-mediated hepatitis and restored the impaired Treg/Th17 cell ratio, which suggests that it may serve as a novel treatment approach for immune-mediated liver diseases.

Role of Foxp3/Treg and RORγt/Th17 imbalance in chronic hepatitis B virus infection

A wide range of immune-mediated liver damage can be seen during infection with hepatitis B virus (HBV). Failure of HBV immune clearance leads to chronic hepatitis and greatly increases the risk of liver cirrhosis and hepatocellular carcinoma. Recently, there have been many studies on the relationship between the outcome of HBV infection and the immune status of patients. The immune response of T lymphocytes in HBV infection plays an important role, especially the imbalance of regulatory T cells (Treg)/Helper T cell 17 (Th17). The imbalance between the Treg and Th17 is an important mechanism of persistent HBV infection and inflammatory injury of the liver. To better reveal the underlying mechanisms, we systematically review the roles of Treg and Th17 and discuss the relationship between Treg and Th17 during HBV infection as well as the changes in the two related specific transcription factors, retinoid-related orphan nuclear receptor γt (RORγt) and forkhead/winged helix family transcription factor 3 (Foxp3). The research on HBV immunotargeting therapy in recent years has suggested the role of Foxp3/Treg and RORγt/Th17 imbalance in HBV infection. Such findings provide new ideas for the treatment of chronic hepatitis B.

Th17/Treg cell level and clinical characteristics of peripheral blood of patients with Sjogren's syndrome complicated with primary biliary cirrhosis

This study aims at analyzing the Th17/Treg cell level and clinical characteristics of the peripheral blood of patients with Sjogren's syndrome (SS) complicated with primary biliary cirrhosis (PBC) so as to deepen the understanding of this disease and seek for its possible onset mechanism.A retrospective analysis was conducted on the clinical data of 24 patients [8 (33%) males and 16 (67%) females] with SS complicated with primary biliary cirrhosis, 50 patients with primary SS and 93 healthy volunteers. These patients were divided into 3 groups: experimental group (SS+PBC), control group (SS) and healthy group. Then, peripheral blood was collected and flow cytometry was conducted to detect level of Th17 cells and Treg cells. A fully automatic biochemical detector was used to detect the corresponding liver function index. The correlation analysis was made based on the clinical manifestations and biochemical characteristics.Compared with the healthy group and control group, the experimental group had the highest Th17/Treg cell ratio, and Th17 cell frequency was significantly increased (P <.05). Furthermore, ALT, AST, ALP, γ-GT, TBIL, and other indexes were positively correlated to the Th17/Treg ratio (P <.05).Th17/Treg cell level and its ratio in peripheral blood of patients with SS complicated with primary biliary cirrhosis were significantly unbalanced, indicating that Th17 cells participate in the onset of this disease to a large extent. Furthermore, the Th17/Treg ratio has a certain correlation with some of the liver function indexes, on which a stratified analysis could be made furtherly according to the seriousness of the conditions.

Interleukin-35 modulates the balance between viral specific CD4+CD25+CD127dim/- regulatory T cells and T helper 17 cells in chronic hepatitis B virus infection

Background

Interleukin (IL)-35 regulates imbalance between regulatory T cells (Tregs) and T helper (Th) 17 cells, leading to an important modulator in autoimmune disorder, cancer, and infectious diseases. Our previous study revealed an immunosuppressive activity of IL-35 in chronic hepatitis B virus (HBV) infection. Thus, the aim of the current study was to investigate the role of regulatory function of IL-35 to viral specific Tregs/Th17 cells balance in chronic HBV infection.

Methods

A total of 44 HLA-A2 restricted chronic HBV infected patients, including 21 of chronic hepatitis B (CHB) and 23 of asymptomatic HBV carriers (ASC) were enrolled. Purified CD4⁺ T cells or CD4⁺CD25⁺CD127^dim/− Tregs were stimulated with recombinant IL-35. HBV core antigen specific Tregs and Th17 cells were determined by flow cytometry. FoxP3 and RORγt mRNA was measured by real-time PCR. Cytokines production (IL-10 and IL-17) was investigated by ELISA.

Results

Peripheral viral specific Tregs was comparable between CHB and ASC. However, increased percentage of viral specific Th17 cells was found in CHB, leading to the reduction of Tregs/Th17 ratio in CHB patients. IL-35 stimulation elevated viral specific Tregs, but not Th17 cells frequency, in both CHB and ASC, resulting in the elevation of Tregs/Th17 ratio in both groups. This process was accompanied by increased expression of FoxP3 mRNA and IL-10 production, and decreased IL-17 secretion and STAT3 phosphorylation in purified CD4⁺ T cells. Moreover, IL-35 stimulation inhibited viral specific Th17-like phenotype differentiation from Tregs in CHB patients. Effective anti-HBV therapy did not affect viral specific Tregs/Th17 cells frequency or IL-35 expression in CHB patients, however, reduced responsiveness of CD4⁺ T cells or Tregs to IL-35 stimulation in vitro.

Conclusion

Our findings indicated that IL-35 regulation to viral specific Tregs/Th17 balance may contribute to viral persistence in chronic HBV infection.

Dual effect of T helper cell 17 (Th17) and regulatory T cell (Treg) in liver pathological process: From occurrence to end stage of disease

Liver disease is a complicated pathological status with acute or chronic progressions, causing a series of damages to liver and massive burden to public health and society. Th17 and Treg, two subsets of CD4⁺ T helper cells, seem to keep a subtle balance in the maintenance of organic immune homeostasis including liver. The dysfunction of Th17/Treg balance in liver has been proved associated with hepatic injury and disease. Herein, we summarized the research advance of Th17 and Treg cells in different phenotypes of liver diseases in the past decade. It is known to all that hepatic diseases start from stimulations or infections like virus, autoimmune, alcohol and so on in the early stage, which would cause inflammation. With the disease consistently existed, severe outcomes like cirrhosis and hepatocellular carcinoma appear finally. In conclusion, it is found that Th17 and Treg cells serve as an important role in the immune response imbalance of liver diseases from the beginning to the end stage. However, the effect of these two subsets of CD4⁺ T helper cells is not a stereotype. Pathological role which exacerbates the disease and protective character which inhibits damage to liver are co-existed in the effect of Th17 and Treg cells. Still, more studies should be carried out to enrich the understandings of liver disease and Th17/Treg immune balance in the future.

Type 3 innate lymphoid cell: a new player in liver fibrosis progression

Type 3 innate lymphoid cell (ILC3) has recently emerged as a crucial effector in inflammatory and fibrotic diseases. The present study was designed to determine the roles of ILC3 in liver fibrosis. By flow cytometry, we documented increased frequencies of peripheral ILC3 (Lin-CD127+CD117+CD294- lymphocytes) in patients, especially at the advanced stage of hepatitis B virus (HBV)-related chronic liver diseases, and demonstrated their correlations with disease progression. The in vitro fibrogenic effects by ILC3 were determined by co-culture experiments with LX-2 (a human hepatic stellate cell (HSC) line). The data indicate that pathogenic ILC3 can directly promote LX-2 fibrogenesis in non-contact manners by producing interleukin (IL)-17A and IL-22. Additionally, they had indirect fibrogenic effects by producing IL-22 to suppress interferon (IFN)-γ (a well-known anti-fibrotic cytokine) production by other immune cells. In carbon tetrachloride (CCl4)-induced wild-type mouse liver fibrosis models, we also documented significantly increased frequencies of both non-natural killer (NK) ILC (Lin-CD127+ lymphocytes) and ILC3 (Lin-CD127+RORγt+ lymphocytes) in liver and spleen specimens. Furthermore, the ILC3 from fibrotic mice contained more IL-17A+ILC3 and IL-22+ILC3 subsets than those from normal and less-fibrotic mice. The in vivo effects of ILC3 in liver fibrogenesis were further determined using RAG-1-/- mice with ILC depletion and further adoptive transfer of ILC3 from wild-type mice. The immunohistochemical staining of liver specimens showed the beneficial effects by ILC depletion and the detrimental effects by ILC3 transfer in CCl4-induced mouse liver fibrosis models. Collectively, ILC3 plays a pro-fibrotic role in liver fibrosis progression.

Chronic intermittent hypoxia promotes the development of experimental non-alcoholic steatohepatitis by modulating Treg/Th17 differentiation

The present study aims to characterize the effect of chronic intermittent hypoxia and HIF1α on the non-alcoholic steatohepatitis (NASH) process in mice, and to explore the role of the Treg/Th17 balance in the formation of NASH inflammation and fibrosis. To achieve this purpose, simple steatosis was induced in mice by high-fat diet administration. Subsequently, chronic intermittent hypoxia was simulated by intraperitoneally injecting sodium nitrite. The changes of inflammation, fibrosis, and Treg/Th17 balance in the liver were quantified under chronic intermittent hypoxia condition and after tail vein injection of HIF1α-siRNA. In addition, T cells were cultured in vitro, and HIF1α expression was either blocked or overexpressed under chronic intermittent hypoxia or normal conditions. Then, the changes of Treg/Th17 balance, inflammatory factors, and cell pathways were measured in each group. Our results demonstrated that chronic intermittent hypoxia accelerates the NASH process, while tail vein injection of HIF1α-siRNA improves liver histology and function. Chronic intermittent hypoxia alters the ratio of Th17 and Treg cells through HIF1α and mTOR signaling, and increases the expressions of NF-κB, IL-6, and IL-17, but decreases IL-10 expression. Inhibition of the mTOR-HIF1α-TLR4-IL-6 pathway increases the ratio of Treg/Th17. Thus, chronic intermittent hypoxia modulates the Treg/Th17 balance by inducing HIF1α, resulting in the activation of the mTOR-HIF1α-TLR4-IL-6 pathway, which accelerates the formation of NASH and fibrosis.

The -3279C>A and -924A>G polymorphisms in the FOXP3 Gene Are Associated With Viral Load and Liver Enzyme Levels in Patients With Chronic Viral Liver Diseases

The transcription factor FOXP3 is an essential marker of the development and activation of regulatory T cells (Tregs), which are cells specialized in the regulation and normal tolerance of the immune response. In the context of chronic viral liver diseases, Tregs participate in the maintenance of infections by promoting histopathological control and favor the immune escape of viral agents by suppressing the antiviral response. Single nucleotide polymorphisms (SNPs) may influence the function of FOXP3 in a number of pathological conditions. The present study sought to evaluate the influence of SNPs in the FOXP3 gene promoter region in patients with chronic viral liver diseases. Three SNPs (−3279C>A, −2383C>T, and −924A>G) were analyzed in groups of patients with chronic hepatitis C (CHC), active chronic hepatitis B (CHB-A), inactive chronic hepatitis B (CHB-I), and a healthy control group (CG) using real-time PCR. The frequencies of the polymorphic variants were compared between groups and correlated with liver histopathological characteristics and enzyme levels [i.e., alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (GGT)] obtained via biopsy and from the clinical records of the participating patients, respectively. For the −2338C>T SNP, no significant differences were found in the frequencies of variants between groups or in the histological findings. Significant associations between the polymorphisms and the CHB-I group were not established. The −3279C>A SNP was associated with altered viral loads (log₁₀) and GGT levels in CHC patients with advanced stages of inflammatory activity and liver fibrosis. The −924A>G SNP was associated with altered viral loads (log₁₀) and liver enzyme levels among CHB-A patients with milder inflammation and fibrosis. However, the frequencies of the −3279C>A and −924A>G polymorphisms were not directly associated with the histopathological profiles of the analyzed patients. These polymorphic variants may influence hepatic function in patients with chronic viral liver diseases but are not directly associated with the establishment of the degree of inflammatory activity and liver fibrosis.

MiR-29a and miR-652 Attenuate Liver Fibrosis by Inhibiting the Differentiation of CD4+ T Cells

BACKGROUND

Liver fibrosis is the response of liver diseases that puzzles patients. MiRNAs were involved in the regulating processes of liver fibrosis. This study aims to investigate the effects of ARRB1 mediated by miR-29a and miR-652 on liver fibrosis and its possible mechanism.

METHODS

Liver fibrosis of mice was induced by intraperitoneal injection of CCl₄. Liver function was observed by the levels of alanine transaminase (ALT) and aspartate transaminase (AST). Flow cytometry was used to detect the percent of T helper17 (Th17). ELISA (Enzyme linked immunoassay) was used to detect the levels of Interleukin-17 (IL-17) and Interleukin-22 (IL-22). Real-time PCR was used to detect the expression of IL-17A, IL-22, miR-29a, miR-652 and β-Arrestin 1 Gene (ARRB1). Western blot was used to detect the protein expression of ARRB1.

RESULTS

CCl₄ supplementation significantly increased the level of ALT and AST, the percent of Th17, the level of IL-17A, IL-22, miR-29a and miR-652, but decreased ARRB1. Overexpression of miR-29a/miR-652 prominently decreased Th17, IL-17A, IL-22 and ARRB1 in the normal CD4+ T cells. Both miR-29a and miR-652 targeted ARRB1 to regulate its expression. The effects of miR-29a/miR-652 overexpression on CD4+ T cells were reversed by ARRB1 overexpression. In vivo experiments demonstrated the protective role of miR-29a/miR-652 overexpression on liver fibrosis.

CONCLUSION

ARRB1 mediated by miR-29a and miR-652 probably involved in the CD4+ T cells differentiation in patients with liver fibrosis, and functioned as a biomarker of fibrosis liver.Key words: liver fibrosis, miR-29a, miR-652, ARRB1, CD4+ T cells.

Expression profiles of transcription factors for special CD4+ T-cell subsets in peripheral blood mononuclear cells from patients with hepatitis B virus infection

This study is to characterize the transcription factor expression profiles for the peripheral CD4 T-cell subsets, and analyze its associations with the clinical measures of the hepatitis B virus (HBV) infection.Totally 275 subjects were included. The expression levels of transcription factors (T-bet, GATA-3, Foxp3, RORγt, and Bcl-6) in the peripheral blood mononuclear cells (PBMCs) were determined by the real-time fluorimetry quantitative PCR (FQ-PCR).Lowest expression levels of all these transcription factors were observed for the HBsAb(-) group, which were higher in the HBsAb(+) and RHB groups. The T-bet/GATA-3 ratios in the CHB and RHB groups were significantly lower than the HBsAb(-) group, whereas the RORγt/Foxp3 ratios in the AHB and RHB groups were significantly higher than the CHB and HBsAb(+) groups. Furthermore, the RORγt mRNA expression levels were significantly different among groups with different disease severities or with different alanine aminotransferase (ALT) levels. The asymptomatic carrier (AsC) group and the group with ALT ≤ 40 had the highest express level. The mRNA expression levels of T-bet, GATA-3, Foxp3, and RORγt varied along with the aspartate aminotransferase (AST) levels, with AST ≤ 40 having the highest expression levels. In addition, significant differences were observed in the transcription factor expression levels between the group with the serum HBV DNA load of (1.000-9.999) × 10 copies/mL and other groups.Expression profile of critical transcription factors for peripheral CD4 T-cell subsets may indicate clinical outcomes of HBV infection.

Immunity and Fibrogenesis: The Role of Th17/IL-17 Axis in HBV and HCV-induced Chronic Hepatitis and Progression to Cirrhosis

Cirrhosis is a common final pathway for most chronic liver diseases; representing an increasing burden worldwide and is associated with increased morbidity and mortality. Current evidence has shown that, after an initial injury, the immune response has a significant participation in the ongoing damage, and progression from chronic viral hepatitis (CVH) to cirrhosis, driving the activation and maintenance of main fibrogenic pathways. Among immune deregulations, those related to the subtype 17 of T helper lymphocytes (Th17)/interleukin-17 (IL-17) axis have been recognized as key immunopathological and prognostic elements in patients with CVH. The Th17/IL-17 axis has been found involved in several points of fibrogenesis chain from the activation of stellate cells, increased expression of profibrotic factors as TGF-β, promotion of the myofibroblastic or epithelial–mesenchymal transition, stimulation of the synthesis of collagen, and induction of imbalance between matrix metalloproteinases and tissue inhibitors of metalloproteinases (TIMPs). It also promotes the recruitment of inflammatory cells and increases the expression of proinflammatory cytokines such as IL-6 and IL-23. So, the Th17/IL-17 axis is simultaneously the fuel and the flame of a sustained proinflammatory and profibrotic environment. This work aims to present the immunopathologic and prognostic role of the Th17/IL-17 axis and related pathways in fibrogenesis and progression to cirrhosis in patients with liver disease due to hepatitis B virus (HBV) and hepatitis C virus (HCV).

Activated hepatic stellate cells directly induce pathogenic Th17 cells in chronic hepatitis B virus infection

Th17 cells are involved in liver fibrosis by activating hepatic stellate cells (HSCs). We aimed to investigate whether HSCs are able to regulate the function of Th17 cells and to determine the relevant mechanism. Sixty-five patients diagnosed with chronic hepatitis B (CHB) were enrolled in this study. To determine the effect of HSCs on T cells, naïve CD4⁺T cells and Th17 cells were sorted from CHB patients and cultured with or without activated-HSCs, and cytokine expression and gene transcription were analyzed. In addition, the regulatory mechanism of HSCs was investigated. ELISA and qRT-PCR showed that Th17 cells from CHB patients were more pathogenic, on the basis of the expression of IL-17A, IL-23R, RORC, CCL20 and CCR6, and meanwhile, they could activate the primary HSCs. Co-culture experiments indicated that activated HSCs dramatically promoted proliferation of CD4⁺T cells in a time- and dose-dependent manner. In addition, they could induce naïve CD4⁺T cells to become Th17 cells which had a more pathogenic phenotype. Moreover, activated HSCs-mediated induction of Th17 cells might depend on the release of IL-1β and IL-6 as well as on the COX-PGE2 pathway. Th17 cells cooperated with HSCs in a proinflammatory feedback loop might provide a better understanding of the pathogenic role of Th17 cells in the chronicity of HBV infection.

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.

Relationship of Treg/Th17 balance with HBeAg change in HBeAg-positive chronic hepatitis B patients receiving telbivudine antiviral treatment: A longitudinal observational study

Telbivudine (LdT) is an orally L-nucleoside with potent and specific antihepatitis B virus (HBV) activity. The higher rate of hepatitis B e antigen (HBeAg) seroconversion of LdT treatment than other anti-HBV agents suggests a potential immunomodulatory effect. The aim of the study was to investigate the changes of regulatory T cell (Treg)/interleukin (IL)-17-producing CD4+T helper (Th17) balance during LdT treatment and to discuss the relationship of Treg/Th17 balance with HBeAg change in HBeAg-positive chronic hepatitis B (CHB) patients receiving LdT antiviral treatment. Twenty-seven HBeAg-positive CHB patients received LdT for 24 weeks and the percentages of Tregs and cells (Th17 cells) in peripheral blood as well as the serum TGF-β1 and IL-17 levels in these patients were longitudinally analyzed. We found that the frequencies of Tregs and Th17 cells in peripheral blood as well as the serum TGF-β1 and IL-17 levels increased significantly in CHB patients compared with healthy controls. During the LdT treatment, the Tregs frequency and TGF-β1 level tended to decrease, and Th17 cells frequency and IL-17 level showed a reverse "V"-type change. The frequency of Tregs and the ratio of Treg/Th17 were significantly lower in the HBeAg loss group than those in the HBeAg no-loss group at the baseline. More important, the Tregs frequency and TGF-β1 level were both positively correlated with HBeAg level during the LdT treatment for 24 weeks. Our data suggest that the lower Tregs frequency and Treg/Th17 ratio at the baseline of LdT treatment, the more likely to get the HBeAg loss. HBeAg negative can be predicted using changes in Tregs frequency and TGF-β1 level during LdT treatment in CHB patients. Maybe we could provide the immunology marker for exploring the mechanism of the higher HBeAg seroconversion rate of LdT therapy.

Polymorphism of TLR5 rs5744174 is associated with disease progression in Chinese patients with chronic HBV infection

Toll-like receptors (TLRs) play a crucial role in innate and adaptive immunity, protecting the host from viral pathogens. Studies have implicated that TLR5 is associated with various diseases such as autoimmune and inflammation related diseases. However, little is known about the relationship between TLR5 and hepatitis B virus (HBV) infection. We studied the effect of TLR5 gene polymorphisms on susceptibility to and disease progression of chronic hepatitis B (CHB) infection in Chinese. Blood samples were taken from 636 patients with CHB, HBV-related liver cirrhosis (LC) or hepatocellular carcinoma (HCC) and 273 controls. Polymorphisms of TLR5 (1775A>G rs2072493 and 1846T>C rs5744174) were analyzed by PCR-based sequencing. No difference in genotypic and allelic frequencies of TLR5 rs2072493 and rs5744174 was observed between patients and controls. Significant difference was found in frequency of TLR5 rs5744174 TT genotype between men with CHB and LC (p = 0.035). Frequency of TT genotype of TLR5 rs5744174 in patients positive for HBeAg was increased from 53.2% in patients with CHB to 74.1% in those with HCC (p = 0.024). Our results indicate that in Chinese genetic variation of TLR5 may be not a determinant of susceptibility to HBV-related diseases but may play a role in development of HBV-related severe liver diseases.

Decreased frequency of circulating Th9 cells in patients with chronic hepatitis B infection

BACKGROUND

Chronic hepatitis B (CHB) is one of the major infectious diseases in which CD4+ T helper (Th) cells play a crucial role. Th9 cells are a distinct subset of CD4+ Th cells with important physiological functions.

OBJECTIVE

The study aimed to assess the potential involvement of Th9 cells in the inadequate immune response leading to chronic HBV infection.

PATIENTS AND METHODS

Peripheral blood samples were collected from 22 CHB patients and 16 healthy controls (HC). The frequencies of circulating Th9, Tc9, Th1, and Tc1 cells were determined by flow cytometry. Serum levels of IL-9 and IL-10 were analyzed by ELISA. Serum biochemical indices of liver function were measured using an automated analyzers. Serum HBV DNA loads were analyzed by real-time PCR. The potential association of the frequency of Th9, Tc9, Th1 or Tc1 cells with clinical parameters was assessed.

RESULTS

The frequency of circulating Th9 cells was significantly lower in CHB patients than those in HC. However, no significant differences in the frequency of Tc9, Th1 or Tc1 cells were observed between the two groups. The percentages of Th9 cells, but not Tc9 cells, were negatively correlated with HBV DNA loads, whereas the percentages of Tc1 cells were positively correlated with viral loads in CHB patients. Moreover, there was a positive correlation between serum levels of IL-9 and IL-10 and HBV DNA loads in patients with chronic HBV infection.

CONCLUSION

The depletion of Th9 cells is associated with the development of chronic HBV infection.

1,25(OH)2D3 Protects Liver Fibrosis Through Decreasing the Generation of TH17 Cells

BACKGROUND The aim of this study was to study the effects of 1-alpha,25-dihydroxy-cholecalcifero (1,25(OH)2D3) on liver fibrosis and the generation of Th17 cells in vivo and in vitro. MATERIAL AND METHODS Thirty C57 mice were randomly divided into control, model, and treatment groups. Hepatic fibrosis was induced by subcutaneous injection of CCl4. Liver fibrosis condition was evaluated through pathological inspection and blood biochemical examination of liver function. Immunohistochemical assays were used to detect the expression of α-SMA, TGF-β, and collagen I to observe hepatic stellate cell activation level. Flow cytometry, ELISA, and RT-PCR were performed to explore the association between 1,25(OH)2D3 and Th17 cell differentiation. RESULTS Collagen I, TGF-β, and α-SMA were decreased after 1,25(OH)2D3 treatment. Consistently, RORγt mRNA and the rate of Th17 cells was significantly reduced after 1,25(OH)2D3 treatment. In vitro, the proportion of Th17 cells was also obviously reduced in the 1,25(OH)2D3 group, and mRNA levels of IL-17A, IL-22, RORγt, and RORa were significantly decrease in the 1,25(OH)2D3 group compared to the control group. CONCLUSIONS Treatment with 1,25(OH)2D3 can alleviate the damage caused by liver fibrosis. Experiments in vivo and in vitro showed that 1,25(OH)2D3 treatment deceased the rates of Th1 and Th17 cells and increased the rate of Th2 cells. The level of IL-17A, IL-22 and IFN-γ were decreased, while the level of IL-4 was increased by the treatment of 1,25(OH)2D3.

Levels of hepatic Th17 cells and regulatory T cells upregulated by hepatic stellate cells in advanced HBV-related liver fibrosis

Background

Liver fibrosis which mainly occurs upon chronic hepatitis virus infection potentially leads to portal hypertension, hepatic failure and hepatocellular carcinoma. However, the immune status of Th17 and Treg cells in liver fibrosis is controversial and the exact mechanisms remain largely elusive.

Methods

Liver tissues and peripheral blood were obtained simultaneously from 32 hepatitis B virus infected patients undergoing surgery for hepatocellular carcinoma at the medical center of Sun Yat-sen University. Liver tissues at least 3 cm away from the tumor site were used for the analyses. Levels of Th17 cells and regulatory T cells were detected by flow cytometry analysis and immunohistochemistry. In vitro experiment, we adopted magnetic cell sorting to investigate how hepatic stellate cells regulate the levels of Th17 cells and regulatory T cells.

Results

We found that hepatic Th17 cells and regulatory T cells were increased in patients with advanced stage HBV-related liver fibrosis. Hepatic stellate cells upregulated the levels of Th17 cells and regulatory T cells via PGE2/EP2 and EP4 pathway.

Conclusions

We found that the increased levels of Th17 cells and regulatory T cells were upregulated by hepatic stellate cells. These results may provide insight into the role of hepatic stellate cells and Th17 cells and regulatory T cells in the persistence of fibrosis and into the occurrence of hepatocellular carcinoma following cirrhosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1167-y) contains supplementary material, which is available to authorized users.

HMGB1-induced autophagy: a new pathway to maintain Treg function during chronic hepatitis B virus infection

High-mobility group box-1 (HMGB1) protein, as one of the well-known damage-associated molecular pattern molecules (DAMPs), is enriched in chronic hepatitis B virus (HBV) infection and has a context-dependent role in autophagy, a highly conserved self-digestive process in response to environmental stress. Recent mouse studies indicate that autophagy is highly active in regulatory T (Treg)-cells. In the present study, we evaluated spontaneous and induced autophagy of peripheral Treg cells from 98 patients with chronic hepatitis B (CHB), by measuring levels of lipidated form of microtubule-associated light chain 3 (LC3-II, marker for closed autophagosomes) and observing autophagic vacuoles (AV) with transmission electron microscope. No significant difference was found in spontaneous autophagy of either Treg or CD4+ naive cells when comparing CHB patients with healthy subjects, apart from CHB-Treg showed significantly higher autophagic activity after activation by anti-CD3–CD28 beads. Besides, incubation of CHB-Treg cells with CHB-serum greatly maintained their autophagic behaviour, which could be significantly diminished by blocking HMGB1 with the neutralizing antibody. Further, we characterized time- and dose-dependent effects by recombinant HMGB1 protein on autophagy of CHB-Treg cells. We also documented a significant up-regulation of HMGB1 and its receptors [toll-like receptor (TLR4), receptor for advanced glycation end-product (RAGE)] in both peripheral and intra-hepatic microenvironments of CHB patients. Moreover, the RAGE–extracellular regulated protein kinases (ERK) axis and rapamycin-sensitive components of mammalian target of rapamycin (mTOR) pathways were demonstrated in vitro to be involved in HMGB1-induced autophagy of Treg cells. Additionally, HMGB1-induced autophagy could maintain cell survival and functional stability of CHB-Treg cells. Our findings could open new perspectives in developing therapeutic strategies to activate specific anti-HBV immunity by diminishing Treg autophagy.