IL-13 Signaling in Liver Fibrogenesis

Cytokine Profile of Adipose-Derived Stem Cells From Patients With Burn Injuries and Infection

INTRODUCTION

Adipose-derived stem cells (ASCs) are multipotent stem cells capable of differentiating into many cell lineages. They play an important role in wound healing by secreting cytokines. Prior studies have demonstrated the presence of proinflammatory cytokines in burn wounds. However, no studies have been performed evaluating the cytokines released by burn wounds with infections. We hypothesized that there is an alteration in the paracrine factors secreted by ASCs in burn wounds with concomitant infections.

METHODS

Adipose tissue was collected from patients with burn injuries at their index operation. ASCs were extracted and grown under standard tissue culture techniques. The supernatant was extracted. Cytokine analyses were performed with multiplex assays. Infection was determined using a burn sepsis protocol. The cytokine profiles of the two groups were compared using a Mann-Whitney U test.

RESULTS

Sixteen patients were enrolled in the study, 50% with bacterial infection (n = 8). There was no significant difference in the baseline demographics of the two groups (P > 0.05). There were significantly lower concentrations of interleukin 13 and interferon gamma (P < 0.05) in burn patients with concomitant infections.

CONCLUSIONS

ASCs are critical to burn wound healing. This study demonstrated diminished production of interleukin 13, an immunoregulatory cytokine involved in the antiinflammatory pathway by downregulating macrophage activity. This study also demonstrated significantly lower levels of interferon gamma in patient with burns and concomitant infection. This cytokine is crucial for antimicrobial defenses.

The mechanism of IL-13 targeting IL-13Rα2 in regulating oral mucosal FBs through PI3K/AKT/mTOR

OBJECTIVE

The objective of this investigation was to examine the presence of interleukin (IL)-13 and its receptor IL-13Rα2 in the tissues of oral submucous fibrosis (OSF), investigate their biological functions, and explore the underlying mechanisms involved in the development of OSF.

MATERIALS AND METHODS

The expression of IL-13 and IL-13Rα2 in the oral mucosa of patients with OSF and normal individuals was determined through immunohistochemistry and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Primary fibroblasts (FBs) were extracted through enzymatic digestion and then cultured. Immunofluorescence was employed to identify the FB cultures and the location of IL-13Rα2. The effects of IL-13/IL-13Rα2/PI3K/AKT/mTOR on the migration, proliferation, and secretion of fiber-related proteins of FBs were explored via the wound healing assay, CCK-8 assay, EDU assay, and RT-qPCR. The impact of IL-13Rα2 silencing and PI3K/AKT inhibition on the effect of IL-13 on FBs was analyzed by RT-qPCR and Western blotting.

RESULTS

IL-13 and IL-13Rα2 were highly expressed in OSF. Primary FBs were successfully extracted and cultured. IL-13Rα2 was found to be localized in myofibroblasts. IL-13 promoted the proliferation, migration, and secretion of fibril-associated proteins in FBs. The proliferation, migration, and secretion of fibril-associated proteins of FBs were decreased following IL-13Rα2 silencing and inhibition of the PI3K/AKT/mTOR pathway.

CONCLUSION

IL-13 may promote the proliferation, migration, and secretion of fiber-related proteins of FBs through the PI3K/AKT/mTOR pathway by targeting IL-13Rα2.

Inflammatory Markers Involved in the Pathogenesis of Dupuytren's Contracture

Dupuytren's disease is a common fibroproliferative disease that can result in debilitating hand deformities. Partial correction and return of deformity are common with surgical or clinical treatments at present. While current treatments are limited to local procedures for relatively late effects of the disease, the pathophysiology of this connective tissue disorder is associated with both local and systemic processes (e.g., fibrosis, inflammation). Hence, a better understanding of the systemic circulation of Dupuytren related cytokines and growth factors may provide important insights into disease progression. In addition, systemic biomarker analysis could yield new concepts for treatments of Dupuytren that attenuate circulatory factors (e.g., anti-inflammatory agents, neutralizing antibodies). Progress in the development of any disease modifying biologic treatment for Dupuytren has been hampered by the lack of clinically useful biomarkers. The characterization of nonsurgical Dupuytren biomarkers will permit disease staging from diagnostic and prognostic perspectives, as well as allows evaluation of biologic responses to treatment. Identification of such markers may transcend their use in Dupuytren treatment, because fibrotic biological processes fundamental to Dupuytren are relevant to fibrosis in many other connective tissues and organs with collagen-based tissue compartments. There is a wide range of potential Dupuytren biomarker categories that could be informative, including disease determinants linked to genetics, collagen metabolism, as well as immunity and inflammation (e.g., cytokines, chemokines). This narrative review provides a broad overview of previous studies and emphasizes the importance of inflammatory mediators as candidate circulating biomarkers for monitoring Dupuytren's disease.

Th2 Cell Activation in Chronic Liver Disease Is Driven by Local IL33 and Contributes to IL13-Dependent Fibrogenesis

BACKGROUND & AIMS

Type 2 immune responses contribute to liver fibrosis in parasite infections, but their role in other liver diseases is less well understood. Here, we aimed at unravelling mechanisms involved in T helper 2 (Th2) T-cell polarization, activation, and recruitment in human liver fibrosis and cirrhosis.

METHODS

Tissues, cells, and serum from human livers were analyzed using quantitative reverse-transcription polymerase chain reaction, enzyme-linked immunosorbent assay, fluorescence in situ hybridization, immunostaining, flow cytometry, and various functional in vitro assays. Cellular interactions and soluble mediators involved in T-cell polarization and recruitment were studied, as well as their effect on hepatic stellate cell (HSC) activation, proliferation, and extracellular matrix synthesis.

RESULTS

In human liver fibrosis, a stage-dependent increase in Th2-related transcription factors, Th2 cytokines, and trans-acting T-cell-specific transcription factor-expressing T cells was observed, and was highest in cirrhotic livers. The alarmin interleukin (IL)33 was found to be increased in livers and sera from patients with cirrhosis, to act as a chemotactic agent for Th2 cells, and to induce type 2 polarization of CD4+ T cells. Oval cells, liver sinusoidal endothelial cells, intrahepatic macrophages, and migrating monocytes were identified as sources of IL33. IL33-activated T cells, but not IL33 alone, induced HSC activation, as shown by Ki67 and α-smooth muscle actin staining, increased collagen type I alpha 1 chain messenger RNA expression, and wound healing assays. The profibrotic effect of IL33-activated T cells was contact-independent and could be antagonized using monoclonal antibodies against IL13.

CONCLUSION

In patients with chronic liver disease, the alarmin IL33 promotes the recruitment and activation of CD4+ T cells with Th2-like properties, which activate paracrine HSC in an IL13-dependent manner and promotes fibrogenesis.

Type 1 invariant natural killer T cells in chronic inflammation and tissue fibrosis

Chronic tissue inflammation often results in fibrosis characterized by the accumulation of extracellular matrix components remodeling normal tissue architecture and function. Recent studies have suggested common immune mechanisms despite the complexity of the interactions between tissue-specific fibroblasts, macrophages, and distinct immune cell populations that mediate fibrosis in various tissues. Natural killer T (NKT) cells recognizing lipid antigens bound to CD1d molecules have been shown to play an important role in chronic inflammation and fibrosis. Here we review recent data in both experimental models and in humans that suggest a key role of type 1 invariant NKT (iNKT) cell activation in the progression of inflammatory cascades leading to recruitment of neutrophils and activation of the inflammasome, macrophages, fibroblasts, and, ultimately, fibrosis. Emerging evidence suggests that iNKT-associated mechanisms contribute to type 1, type 2 and type 3 immune pathways mediating tissue fibrosis, including idiopathic pulmonary fibrosis (IPF). Thus, targeting a pathway upstream of these immune mechanisms, such as the inhibition of iNKT activation, may be important in modulating various fibrotic conditions.

Functionally Relevant Cytokine/Receptor Axes in Myelofibrosis

Dysregulated inflammatory signaling is a key feature of myeloproliferative neoplasms (MPNs), most notably of myelofibrosis (MF). Indeed, MF is considered the prototype of onco-inflammatory hematologic cancers. While increased levels of circulatory and bone marrow cytokines are a well-established feature of all MPNs, a very recent body of literature is intriguingly pinpointing the selective overexpression of cytokine receptors by MF hematopoietic stem and progenitor cells (HSPCs), which, by contrast, are nearly absent or scarcely expressed in essential thrombocythemia (ET) or polycythemia vera (PV) cells. This new evidence suggests that MF CD34+ cells are uniquely capable of sensing inflammation, and that activation of specific cytokine signaling axes may contribute to the peculiar aggressive phenotype and biological behavior of this disorder. In this review, we will cover the main cytokine systems peculiarly activated in MF and how cytokine receptor targeting is shaping a novel therapeutic avenue in this disease.

Identification and characterization of a hepatic IL-13-producing ILC3-like population potentially involved in liver fibrosis

BACKGROUND AND AIMS

Human innate lymphoid cells (ILCs) are critically involved in the modulation of homeostatic and inflammatory processes in various tissues. However, only little is known about the composition of the intrahepatic ILC pool and its potential role in chronic liver disease. Here, we performed a detailed characterization of intrahepatic ILCs in both healthy and fibrotic livers.

APPROACH AND RESULTS

A total of 50 livers (nonfibrotic = 22, and fibrotic = 29) were analyzed and compared with colon and tonsil tissue (each N = 14) and peripheral blood (N = 32). Human intrahepatic ILCs were characterized ex vivo and on stimulation using flow cytometry and single-cell RNA sequencing. ILC differentiation and plasticity were analyzed by both bulk and clonal expansion experiments. Finally, the effects of ILC-derived cytokines on primary human HSteCs were studied. Unexpectedly, we found that an "unconventional" ILC3-like cell represented the major IL-13-producing liver ILC subset. IL-13 + ILC3-like cells were specifically enriched in the human liver, and increased frequencies of this cell type were found in fibrotic livers. ILC3-derived IL-13 production induced upregulation of proinflammatory genes in HSteCs, indicating a potential role in the regulation of hepatic fibrogenesis. Finally, we identified KLRG1-expressing ILC precursors as the potential progenitor of hepatic IL-13 + ILC3-like cells.

CONCLUSIONS

We identified a formerly undescribed subset of IL-13-producing ILC3-like cells that is enriched in the human liver and may be involved in the modulation of chronic liver disease.

Mild Cognitive Impairment Is Associated with Enhanced Activation of Th17 Lymphocytes in Non-Alcoholic Fatty Liver Disease

Patients with nonalcoholic fatty liver disease (NAFLD) may show mild cognitive impairment (MCI). The mechanisms involved remain unclear. The plasma concentrations of several cytokines and chemokines were measured in 71 NAFLD patients (20 with and 51 without MCI) and 61 controls. Characterization and activation of leukocyte populations and CD4⁺ sub-populations were carried out and analyzed by flow cytometry. We analyzed the cytokines released from CD4⁺ cell cultures and the mRNA expression of transcription factors and receptors in peripheral blood mononuclear cells. The appearance of MCI in NAFLD patients was associated with increased activation of CD4⁺ T lymphocytes, mainly of the Th17 subtype, increased plasma levels of pro-inflammatory and anti-inflammatory cytokines such as IL-17A, IL-23, IL-21, IL-22, IL-6, INF-γ, and IL-13, and higher expression of the CCR2 receptor. Constitutive expression of IL-17 was found in cultures of CD4⁺ cells from MCI patients, reflecting Th17 activation. High IL-13 plasma levels were predictive of MCI and could reflect a compensatory anti-inflammatory response to the increased expression of pro-inflammatory cytokines. This study identified some specific alterations of the immune system associated with the appearance of neurological alterations in MCI patients with NAFLD that could be the basis to improve and restore cognitive functions and quality of life in these patients.

Repetitive schistosoma exposure causes perivascular lung fibrosis and persistent pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) can occur as a complication of schistosomiasis. In humans, schistosomiasis-PH persists despite antihelminthic therapy and parasite eradication. We hypothesized that persistent disease arises as a consequence of exposure repetition.

METHODS

Following intraperitoneal sensitization, mice were experimentally exposed to Schistosoma eggs by intravenous injection, either once or three times repeatedly. The phenotype was characterized by right heart catheterization and tissue analysis.

RESULTS

Following intraperitoneal sensitization, a single intravenous Schistosoma egg exposure resulted in a PH phenotype that peaked at 7-14 days, followed by spontaneous resolution. Three sequential exposures resulted in a persistent PH phenotype. Inflammatory cytokines were not significantly different between mice exposed to one or three egg doses, but there was an increase in perivascular fibrosis in those who received three egg doses. Significant perivascular fibrosis was also observed in autopsy specimens from patients who died of this condition.

CONCLUSIONS

Repeatedly exposing mice to schistosomiasis causes a persistent PH phenotype, accompanied by perivascular fibrosis. Perivascular fibrosis may contribute to the persistent schistosomiasis-PH observed in humans with this disease.

Blockade of CCR4 breaks immune tolerance in chronic hepatitis B patients by modulating regulatory pathways

BACKGROUND

Immunotargets including checkpoint inhibitors and toll-like receptor 8 agonists have recently gained attention for the recovery of hepatitis B virus (HBV)-specific T cell exhaustion in chronic hepatitis B(CHB). Chemokine receptors have a similar significant role during viral infections; however, their role in CHB remains poorly understood. Therefore, in this study we evaluated the role of chemokine receptor 4 (CCR4) in deriving immunosuppression during CHB.

METHODS

We characterized CCR4+CD8+ T cells in CHB and identified their involvement in immunosuppression. Further, we examined if CCR4 blockade with mogamulizumab antibody can recover the functional exhaustion in HBsAg-specific T cells.

RESULTS

CHB patients exhibit higher frequency of CCR4+CD8+ T cells that increase with higher HBsAg levels and fibrosis scores. In vitro, HBs antigen triggers CCR4 expression. These cells express multiple inhibitory receptors and exhibit immunosuppressive functions by producing excessive immunoregulatory cytokines IL-4, IL-5, IL-10 and TGF-β1. CCR4 Blockade significantly boosted HBsAg-specific antiviral-cytokine production(IFN-γ, TNF-α and IL-21) in T cells through enhancing their proliferation capacity and polarizing these cells towards T helper 1(Th1) and T follicular helper cells(T_FH) in case of CD4 cells, and cytotoxic T cell 1(TC1) and cytotoxic T follicular(T_CF) cells in case of CD8. Cytotoxic potential was improved, while no induction of immunosuppressive-cytokines was seen after anti-CCR4 treatment thereby eliminating the risk of treatment-induced immunosuppression. CCR4 blockade inhibited the development and effector function of Tregs by controlling their expansion and TGF-β1 production preventing Tregs-induced immunotolearance.

CONCLUSIONS

CCR4 blockade reconstitutes antiviral immune response in T cells and limits the immunosuppressive functions of Tregs, representing them as a promising immunotherapeutic target for functional cure of CHB.

Immunological mechanisms involved in macrophage activation and polarization in schistosomiasis

Human schistosomiasis is caused by helminths of the genus Schistosoma. Macrophages play a crucial role in the immune regulation of this disease. These cells acquire different phenotypes depending on the type of stimulus they receive. M1 macrophages can be ‘classically activated’ and can display a proinflammatory phenotype. M2 or ‘alternatively activated’ macrophages are considered anti-inflammatory cells. Despite the relevance of macrophages in controlling infections, the role of the functional types of these cells in schistosomiasis is unclear. This review highlights different molecules and/or macrophage activation and polarization pathways during Schistosoma mansoni and Schistosoma japonicum infection. This review is based on original and review articles obtained through searches in major databases, including Scopus, Google Scholar, ACS, PubMed, Wiley, Scielo, Web of Science, LILACS and ScienceDirect. Our findings emphasize the importance of S. mansoni and S. japonicum antigens in macrophage polarization, as they exert immunomodulatory effects in different stages of the disease and are therefore important as therapeutic targets for schistosomiasis and in vaccine development. A combination of different antigens can provide greater protection, as it possibly stimulates an adequate immune response for an M1 or M2 profile and leads to host resistance; however, this warrants in vitro and in vivo studies.

DHEA and Its Metabolites Reduce the Cytokines Involved in the Inflammatory Response and Fibrosis in Primary Biliary Cholangitis

Dehydroepiandrosterone (DHEA) is an abundant steroid and precursor of sex hormones. During aging, the reduction in DHEA synthesis causes a significant depletion of estrogens and androgens in different organs, such as the ovaries, brain, and liver. Primary Biliary Cholangitis (PBC) is a cholestatic liver disease that begins with immune-mediated bile duct damage, and is followed by liver fibrosis, and finally, cirrhosis. PBC primarily affects postmenopausal women, with an average age of diagnosis of 65 years, but younger women are also affected. Here, we analyzed the levels of DHEA, estradiol (E2), and estriol (E3) in the PBC sera of females at an age of diagnosis under 40 (n = 37) and above 65 (n = 29). Our results indicate that in PBC patients at an age of diagnosis under 40, E2 was significantly lower compared to that in healthy women. In contrast, the levels of DHEA and E3 were in a normal range. Furthermore, ELISA assays revealed that in PBC patients at an age of diagnosis above 65, the levels of DHEA, E2, and E3 significantly declined in comparison to those in younger patients. In addition, flow cytometry analysis showed that the level of IL-8 significantly decreased while the level of TNF-α increased in older PBC patients compared to younger ones. Moreover, we showed for the first time that the sulfonated form of DHEA, DHEA-S, reduces the levels of both pro-inflammatory interleukins, IL-8 and TNF-α, in PBC-like cholangiocytes (H69-miR506), while it diminishes the level of the pro-fibrotic interleukin, IL-13, in hepatocytes (Hep-G2). Finally, we demonstrated that the expression of the pro-fibrotic agent TGF-β significantly increased in both the early (F0–F3) and cirrhotic (F4) stages of PBC, and this elevation was accompanied by higher α-SMA expression.

Pathology and molecular mechanisms of Schistosoma japonicum-associated liver fibrosis

Schistosomiasis has been widely disseminated around the world, and poses a significant threat to human health. Schistosoma eggs and soluble egg antigen (SEA) mediated inflammatory responses promote the formation of egg granulomas and liver fibrosis. With continuous liver injuries and inflammatory stimulation, liver fibrosis can develop into liver cirrhosis and liver cancer. Therefore, anti-fibrotic therapy is crucial to increase the survival rate of patients. However, current research on antifibrotic treatments for schistosomiasis requires further exploration. In the complicated microenvironment of schistosome infections, it is important to understand the mechanism and pathology of schistosomiasis-associated liver fibrosis(SSLF). In this review, we discuss the role of SEA in inhibiting liver fibrosis, describe its mechanism, and comprehensively explore the role of host-derived and schistosome-derived microRNAs (miRNAs) in SSLF. Inflammasomes and cytokines are significant factors in promoting SSLF, and we discuss the mechanisms of some critical inflammatory signals and pro-fibrotic cytokines. Natural killer(NK) cells and Natural killer T(NKT) cells can inhibit SSLF but are rarely described, therefore, we highlight their significance. This summarizes and provides insights into the mechanisms of key molecules involved in SSLF development.

The Role of Mesothelin in Activation of Portal Fibroblasts in Cholestatic Liver Injury

Fibrosis is a common consequence of abnormal wound healing, which is characterized by infiltration of myofibroblasts and formation of fibrous scar. In liver fibrosis, activated Hepatic Stellate Cells (aHSCs) and activated Portal Fibroblasts (aPFs) are the major contributors to the origin of hepatic myofibroblasts. aPFs are significantly involved in the pathogenesis of cholestatic fibrosis, suggesting that aPFs may be a primary target for anti-fibrotic therapy in cholestatic injury. aPFs are distinguishable from aHSCs by specific markers including mesothelin (Msln), Mucin 16 (Muc16), and Thymus cell antigen 1 (Thy1, CD90) as well as fibulin 2, elastin, Gremlin 1, ecto-ATPase nucleoside triphosphate diphosphohydrolase 2. Msln plays a critical role in activation of PFs, via formation of Msln-Muc16-Thy1 complex that regulates TGFβ1/TGFβRI-mediated fibrogenic signaling. The opposing pro- and anti-fibrogenic effects of Msln and Thy1 are key components of the TGFβ1-induced activation pathway in aPFs. In addition, aPFs and activated lung and kidney fibroblasts share similarities across different organs with expression of common markers and activation cascade including Msln-Thy1 interaction. Here, we summarize the potential function of Msln in activation of PFs and development of cholestatic fibrosis, offering a novel perspective for anti-fibrotic therapy targeting Msln.

Th22 cytokines and yellow fever: Possible implications for the immunopathogenesis of human liver infection

Yellow fever (YF) is an infectious disease considered a public health problem in tropical and subtropical areas. YF has many pathophysiological events that are correlated with the host immune response. In this study, the in situ Th22 cytokine profile was evaluated. Liver tissue samples were collected from 21 YFV-positive patients who died of the disease and five flavivirus-negative controls who died of other causes and whose hepatic parenchyma architecture was preserved. Immunohistochemical (IHC) analysis of tissues in the hepatic parenchyma of YF cases showed significantly higher expression of interleukin (IL)-22, IL-13, tumour necrosis factor-alpha, and FGF basic (FGF b) in YFV-positive cases than that in flavivirus-negative controls. These results indicate that the response of Th22 cytokines emerges as an alternative for a better understanding of adaptive immunity in the hepatic parenchyma, highlighting the role of cytokines in the repair and suppressive responses in the immunopathogenesis of YFV infection.

From Inflammation to Fibrosis: Novel Insights into the Roles of High Mobility Group Protein Box 1 in Schistosome-Induced Liver Damage

Schistosomiasis is a chronic helminthic disease of both humans and animals and the second most prevalent parasitic disease after malaria. Through a complex migration process, schistosome eggs trapped in the liver can lead to the formation of granulomas and subsequent schistosome-induced liver damage, which results in high mortality and morbidity. Although praziquantel can eliminate mature worms and prevent egg deposition, effective drugs to reverse schistosome-induced liver damage are scarce. High mobility group box 1 (HMGB1) is a multifunctional cytokine contributing to liver injury, inflammation, and immune responses in schistosomiasis by binding to cell-surface Toll-like receptors and receptors for advanced glycation end products. HMGB1 is increased in the serum of patients with schistosomiasis and enables hepatic stellate cells to adopt a proliferative myofibroblast-like phenotype, which is crucial to schistosome-induced granuloma formation. Inhibition of HMGB1 was found to generate protective responses against fibrotic diseases in animal models. Clinically, HMGB1 presents a potential target for treatment of the chronic sequelae of schistosomiasis. Here, the pivotal role of HMGB1 in granuloma formation and schistosome-induced liver damage, as well the potential of HMGB1 as a therapeutic target, are discussed.

Macrophages as key regulators of liver health and disease

Macrophages are a heterogeneous population of innate immune cells and key cellular components of the liver. Hepatic macrophages consist of embryologically-derived resident Kupffer cells (KC), recruited monocyte-derived macrophages (MDM) and capsular macrophages. Both the diversity and plasticity of hepatic macrophage subsets explain their different functions in the maintenance of hepatic homeostasis and in injury processes in acute and chronic liver diseases. In this review, we assess the evidence for macrophage involvement in regulating both liver health and injury responses in liver diseases including acute liver injury (ALI), chronic liver disease (CLD) (including liver fibrosis) and hepatocellular carcinoma (HCC). In healthy livers, KC display critical functions such as phagocytosis, danger signal recognition, cytokine release, antigen processing and the ability to orchestrate immune responses and maintain immunological tolerance. However, in most liver diseases there is a striking hepatic MDM expansion, which orchestrate both disease progression and regression. Single-cell approaches have transformed our understanding of liver macrophage heterogeneity, dynamics, and functions in both human samples and preclinical models. We will further discuss the new insights provided by these approaches and how they are enabling high-fidelity work to specifically identify pathogenic macrophage subpopulations. Given the important role of macrophages in regulating injury responses in a broad range of settings, there is now a huge interest in developing new therapeutic strategies aimed at targeting macrophages. Therefore, we also review the current approaches being used to modulate macrophage function in liver diseases and discuss the therapeutic potential of targeting macrophage subpopulations as a novel treatment strategy for patients with liver disorders.

Is the Macrophage Phenotype Determinant for Fibrosis Development?

Fibrosis is a pathophysiological process of wound repair that leads to the deposit of connective tissue in the extracellular matrix. This complication is mainly associated with different pathologies affecting several organs such as lung, liver, heart, kidney, and intestine. In this fibrotic process, macrophages play an important role since they can modulate fibrosis due to their high plasticity, being able to adopt different phenotypes depending on the microenvironment in which they are found. In this review, we will try to discuss whether the macrophage phenotype exerts a pivotal role in the fibrosis development in the most important fibrotic scenarios.

Genistein and exercise treatment reduced NASH related HDAC3, IL-13 and MMP-12 expressions in ovariectomized rats fed with high fat high fructose diet

Background and aim

Genistein (GEN) and exercise (Ex) may be regarded as an alternative treatment for non-alcoholic steatohepatitis (NASH). However, the mechanisms behind their therapeutic effects in NASH are not well-understood.

Experimental procedure

This study investigated the roles of histone deacetylase (HDAC)3 and interleukin-(IL-)13 in the NASH model of ovariectomized (OVX) rats fed with high fat high fructose (HFHF) diet.

Results and conclusion

Nine weeks after being fed with HFHF diet, severe NASH pathology with mild fibrosis were seen along with an increase in HDAC3, IL-13 and matrix metalloelastase (MMP-12) expressions in OVX rats. Five weeks of either GEN or Ex treatments abrogated the increase in both HDAC3 and IL-13 expressions in OVX rats fed with HFHF diet and ameliorated NASH features, liver fibrosis and MMP-12 expression. The combination of Gen and Ex, however, did not provide additional benefits on NASH features in OVX rats fed with HFHF diet. These results suggested that GEN and Ex treatments improved HFHF diet induced NASH in OVX rats through the suppression of HDAC3, IL-13 and MMP-12 expression.

•Estrogen deficiency leads to NASH development.

•Either genistein or exercise modulated lipid metabolism reducing steatohepatitis.

•Either genistein or exercise attenuated liver fibrosis improving NASH.

•Combining genistein and exercise did not provide additional benefits.

•Genistein and exercise have beneficial effects in post-menopausal women with NASH.

Extra- and Intra-Cellular Mechanisms of Hepatic Stellate Cell Activation

Hepatic fibrosis is characterized by the pathological accumulation of extracellular matrix (ECM) in the liver resulting from the persistent liver injury and wound-healing reaction induced by various insults. Although hepatic fibrosis is considered reversible after eliminating the cause of injury, chronic injury left unchecked can progress to cirrhosis and liver cancer. A better understanding of the cellular and molecular mechanisms controlling the fibrotic response is needed to develop novel clinical strategies. It is well documented that activated hepatic stellate cells (HSCs) is the most principal cellular players promoting synthesis and deposition of ECM components. In the current review, we discuss pathways of HSC activation, emphasizing emerging extra- and intra-cellular signals that drive this important cellular response to hepatic fibrosis. A number of cell types and external stimuli converge upon HSCs to promote their activation, including hepatocytes, liver sinusoidal endothelial cells, macrophages, cytokines, altered ECM, hepatitis viral infection, enteric dysbiosis, lipid metabolism disorder, exosomes, microRNAs, alcohol, drugs and parasites. We also discuss the emerging signaling pathways and intracellular events that individually or synergistically drive HSC activation, including TGFβ/Smad, Notch, Wnt/β-catenin, Hedgehog and Hippo signaling pathways. These findings will provide novel potential therapeutic targets to arrest or reverse fibrosis and cirrhosis.

Liver Injury and the Macrophage Issue: Molecular and Mechanistic Facts and Their Clinical Relevance

The liver is an essential immunological organ due to its gatekeeper position to bypassing antigens from the intestinal blood flow and microbial products from the intestinal commensals. The tissue-resident liver macrophages, termed Kupffer cells, represent key phagocytes that closely interact with local parenchymal, interstitial and other immunological cells in the liver to maintain homeostasis and tolerance against harmless antigens. Upon liver injury, the pool of hepatic macrophages expands dramatically by infiltrating bone marrow-/monocyte-derived macrophages. The interplay of the injured microenvironment and altered macrophage pool skews the subsequent course of liver injuries. It may range from complete recovery to chronic inflammation, fibrosis, cirrhosis and eventually hepatocellular cancer. This review summarizes current knowledge on the classification and role of hepatic macrophages in the healthy and injured liver.

Immunological and Biochemical Interplay between Cytokines, Oxidative Stress and Schistosomiasis

The host–parasite schistosome relationship relies heavily on the interplay between the strategies imposed by the schistosome worm and the defense mechanisms the host uses to counter the line of attack of the parasite. The ultimate goal of the schistosome parasite entails five important steps: evade elimination tactics, survive within the human host, develop into adult forms, propagate in large numbers, and transmit from one host to the next. The aim of the parasitized host on the other hand is either to cure or limit infection. Therefore, it is a battle between two conflicting aspirations. From the host’s standpoint, infection accompanies a plethora of immunological consequences; some are set in place to defend the host, while most end up promoting chronic disease, which ultimately crosses paths with oxidative stress and cancer. Understanding these networks provides attractive opportunities for anti-schistosome therapeutic development. Hence, this review discusses the mechanisms by which schistosomes modulate the human immune response with ultimate links to oxidative stress and genetic instability.

Autoimmunity as an Etiological Factor of Cancer: The Transformative Potential of Chronic Type 2 Inflammation

Recent epidemiological studies have found an alarming trend of increased cancer incidence in adults younger than 50 years of age and projected a substantial rise in cancer incidence over the next 10 years in this age group. This trend was exemplified in the incidence of non-cardia gastric cancer and its disproportionate impact on non-Hispanic white females under the age of 50. The trend is concurrent with the increasing incidence of autoimmune diseases in industrialized countries, suggesting a causal link between the two. While autoimmunity has been suspected to be a risk factor for some cancers, the exact mechanisms underlying the connection between autoimmunity and cancer remain unclear and are often controversial. The link has been attributed to several mediators such as immune suppression, infection, diet, environment, or, perhaps most plausibly, chronic inflammation because of its well-recognized role in tumorigenesis. In that regard, autoimmune conditions are common causes of chronic inflammation and may trigger repetitive cycles of antigen-specific cell damage, tissue regeneration, and wound healing. Illustrating the connection between autoimmune diseases and cancer are patients who have an increased risk of cancer development associated with genetically predisposed insufficiency of cytotoxic T lymphocyte-associated protein 4 (CTLA4), a prototypical immune checkpoint against autoimmunity and one of the main targets of cancer immune therapy. The tumorigenic process triggered by CTLA4 insufficiency has been shown in a mouse model to be dependent on the type 2 cytokines interleukin-4 (IL4) and interleukin-13 (IL13). In this type 2 inflammatory milieu, crosstalk with type 2 immune cells may initiate epigenetic reprogramming of epithelial cells, leading to a metaplastic differentiation and eventually malignant transformation even in the absence of classical oncogenic mutations. Those findings complement a large body of evidence for type 1, type 3, or other inflammatory mediators in inflammatory tumorigenesis. This review addresses the potential of autoimmunity as a causal factor for tumorigenesis, the underlying inflammatory mechanisms that may vary depending on host-environment variations, and implications to cancer prevention and immunotherapy.

HMGB1: An overview of its roles in the pathogenesis of liver disease

High-mobility group box 1 (HMGB1) is an abundant architectural chromosomal protein that has multiple biologic functions: gene transcription, DNA replication, DNA-damage repair, and cell signaling for inflammation. HMGB1 can be released passively by necrotic cells or secreted actively by activated immune cells into the extracellular milieu after injury. Extracellular HMGB1 acts as a damage-associated molecular pattern to initiate the innate inflammatory response to infection and injury by communicating with neighboring cells through binding to specific cell-surface receptors, including Toll-like receptors (TLRs) and the receptor for advanced glycation end products (RAGE). Numerous studies have suggested HMGB1 to act as a key protein mediating the pathogenesis of chronic and acute liver diseases, including nonalcoholic fatty liver disease, hepatocellular carcinoma, and hepatic ischemia/reperfusion injury. Here, we provide a detailed review that focuses on the role of HMGB1 and HMGB1-mediated inflammatory signaling pathways in the pathogenesis of liver diseases.

Targeting Certain Interleukins as Novel Treatment Options for Liver Fibrosis

The liver is a major metabolic organ and an immunologically complex organ. It produces and uses many substances such as acute phase proteins, cytokines, chemokines, and complementary components to maintain the balance between immunity and tolerance. Interleukins are important immune control cytokines, that are produced by many body cells. In liver injury, interleukins are produced in large amount by various cell types, and act as pro-inflammatory (e.g. interleukin (IL)-6, IL-13, IL-17, and IL-33) as well as anti-inflammatory (e.g. IL-10) functions in hepatic cells. Recently, interleukins are regarded as interesting therapeutic targets for the treatment of liver fibrosis patients. Hepatic cells such as hepatocytes, hepatic stellate cells, and hepatic macrophages are involved to the initiation, perpetuation, and resolution of fibrosis. The understanding of the role of interleukins in such cells provides opportunity for the development of therapeutic target drugs. This paper aims to understand the functional roles of interleukins in hepatic and immune cells when the liver is damaged, and suggests the possibility of interleukins as a new treatment target in liver fibrosis.

Characteristics of the Gut Microbiome and IL-13/TGF-β1 Mediated Fibrosis in Post-Kasai Cholangitis of Biliary Atresia

Aims: Cholangitis in biliary atresia (BA), which accelerates liver fibrosis progression, is among the most common serious complications after Kasai surgery; however, its etiology remains elusive. Gut microbiome migration may contribute to post-Kasai cholangitis. Further, there is no appropriate model of BA post-Kasai cholangitis for use in investigation of its pathogenesis. Methods: We explored the characteristics of gut microbiome in patients with BA before and after Kasai procedure based on 16S rDNA sequencing. We isolated the dominant strain from patient stool samples and established an in vitro model by infecting patient-derived liver organoids. Bulk RNA-seq was performed, and we conducted qPCR, ELISA, and western blot to explore the mechanism of fibrosis. Results: Gut microbiome diversity was lower in patients after, relative to before, Kasai procedure, while the relative abundance of Klebsiella was higher. Patients who developed cholangitis within 1 month after discharge tended to have simpler gut microbiome composition, dominated by Klebsiella. Klebsiella pneumoniae (KPN) was isolated and used for modeling. RNA-seq showed that BA liver organoids expressed markers of hepatic progenitor cells (KRT19, KRT7, EPCAM, etc.) and that organoids were more stable and less heterogeneous among individuals than liver tissues. After infection with KPN, gene expression patterns in BA liver organoids were enriched in pathways related to infection, apoptosis, and fibrosis. Preliminary experiments indicated the presence of IL-13/TGF-β1-mediated fibrosis in post-Kasai cholangitis. Conclusions: Our findings using a newly-developed model, demonstrate a key role for Klebsiella, and a potential mechanism underlying fibrosis in post-Kasai cholangitis, mediated by the IL-13/TGF-β1 pathway.

The IL-33/ST2 pathway is not essential to Th2 stimulation but is key for modulation and survival during chronic infection with Schistosoma mansoni in mice

Morbidity during chronic schistosomiasis has been associated with the induction and modulation of type-2 granulomatous inflammatory response induced by antigens secreted by the eggs, which become trapped in capillary venules of the host tissues, especially in the liver and intestines. IL-33, an alarmin released after cell damage, binds to its ST2 (suppressor of tumorigenicity 2) receptor, expressed in an variety of immune cells, including ILC2 and macrophages, and stimulates the early production of IL-5 and IL-13, which leads to eosinophil infiltration and activation of a Th2 response. However, the role of IL-33/ST2 activation on Schistosoma-induced granuloma formation and modulation is mostly unknown. In the current work, we comparatively evaluated the immune response and granuloma formation in wild-type BALB/c (WT) and BALB/c mice genetically deficient in the IL-33 receptor (ST2^-/-) experimentally infected with Schistosoma mansoni. Mice were infected with 25 or 50 S. mansoni cercariae and followed for up to 14 weeks to assess mortality. Mice from each experimental group were comparatively evaluated for parasite burden, liver immune response, and granuloma appearance during acute and chronic schistosomiasis. Our data showed that the number of circulating worms and eggs retained in the liver and eliminated in the feces was similar in WT and ST2^-/- infected mice, but infected ST2^-/- mice presented an enhanced rate of mortality. Interestingly, the production of type-2 cytokines by soluble egg antigens (SEA)-stimulated spleen cells, the serum concentrations of IL-5 and Immunoglobulin (Ig)-E, and the level of parasite-reactive IgG1 were similar in infected mice of both experimental groups. The concentrations of IL-4, IL-5, IL-13, and IFN-γ in liver homogenate of infected mice also did not differ between the strains at acute schistosomiasis, but there was a significant increase in IL-17 levels in ST2^-/- infected mice at this phase. On the other hand, IL-4, IL-13, IL-10, IL-17, and IFN-γ concentrations were reduced and the ratios of IL-4/IFN-γ and IL-17/IFN-γ were higher in liver homogenate of chronically infected ST2^-/- mice, suggesting unbalanced Th2 and Th17 responses. Moreover, liver granulomas of ST2^-/- mice were larger and disorganized, showing an intense cellular infiltrate, rich in eosinophils and neutrophils. Our results suggest that the absence of the IL-33/ST2 pathway is not essential for the Schistosoma-induced Th2 response, but is necessary to prevent host mortality by modulating granuloma-mediated pathology.

Immunopathobiology and therapeutic targets related to cytokines in liver diseases

Chronic liver injury with any etiology can progress to fibrosis and the end-stage diseases cirrhosis and hepatocellular carcinoma. The progression of liver disease is controlled by a variety of factors, including liver injury, inflammatory cells, inflammatory mediators, cytokines, and the gut microbiome. In the current review, we discuss recent data on a large number of cytokines that play important roles in regulating liver injury, inflammation, fibrosis, and regeneration, with a focus on interferons and T helper (Th) 1, Th2, Th9, Th17, interleukin (IL)-1 family, IL-6 family, and IL-20 family cytokines. Hepatocytes can also produce certain cytokines (such as IL-7, IL-11, and IL-33), and the functions of these cytokines in the liver are briefly summarized. Several cytokines have great therapeutic potential, and some are currently being tested as therapeutic targets in clinical trials for the treatment of liver diseases, which are also described.

Development of a cost-effective automated platform to produce human liver spheroids for basic and applied research

Liver disease represents an increasing cause of global morbidity and mortality. Currently, liver transplant is the only treatment curative for end-stage liver disease. Donor organs cannot meet the demand and therefore scalable treatments and new disease models are required to improve clinical intervention. Pluripotent stem cells represent a renewable source of human tissue. Recent advances in three-dimensional cell culture have provided the field with more complex systems that better mimic liver physiology and function. Despite these improvements, current cell-based models are variable in performance and expensive to manufacture at scale. This is due, in part, to the use of poorly defined or cross-species materials within the process, severely affecting technology translation. To address this issue, we have developed an automated and economical platform to produce liver tissue at scale for modelling disease and small molecule screening. Stem cell derived liver spheres were formed by combining hepatic progenitors with endothelial cells and stellate cells, in the ratios found within the liver. The resulting tissue permitted the study of human liver biology 'in the dish' and could be scaled for screening. In summary, we have developed an automated differentiation system that permits reliable self-assembly of human liver tissue for biomedical application. Going forward we believe that this technology will not only serve as anin vitroresource, and may have an important role to play in supporting failing liver function in humans.

IL-13 as Target to Reduce Cholestasis and Dysbiosis in Abcb4 Knockout Mice

The Th2 cytokine IL-13 is involved in biliary epithelial injury and liver fibrosis in patients as well as in animal models. The aim of this study was to investigate IL-13 as a therapeutic target during short term and chronic intrahepatic cholestasis in an Abcb4-knockout mouse model (Abcb4^-/-). Lack of IL-13 protected Abcb4^-/- mice transiently from cholestasis. This decrease in serum bile acids was accompanied by an enhanced excretion of bile acids and a normalization of fecal bile acid composition. In Abcb4^-/-/IL-13^-/- double knockout mice, bacterial translocation to the liver was significantly reduced and the intestinal microbiome resembled the commensal composition in wild type animals. In addition, 52-week-old Abcb4^-/-IL-13^-/- mice showed significantly reduced hepatic fibrosis. Abcb4^-/- mice devoid of IL-13 transiently improved cholestasis and converted the composition of the gut microbiota towards healthy conditions. This highlights IL-13 as a potential therapeutic target in biliary diseases.

Behind Enemy Lines: Immunomodulatory Armamentarium of the Schistosome Parasite

The deeply rooted, intricate relationship between the Schistosoma parasite and the human host has enabled the parasite to successfully survive within the host and surreptitiously evade the host's immune attacks. The parasite has developed a variety of strategies in its immunomodulatory armamentarium to promote infection without getting harmed or killed in the battlefield of immune responses. These include the production of immunomodulatory molecules, alteration of membranes, and the promotion of granuloma formation. Schistosomiasis thus serves as a paradigm for understanding the Th2 immune responses seen in various helminthiases. This review therefore aims to summarize the immunomodulatory mechanisms of the schistosome parasites to survive inside the host. Understanding these immunomodulatory strategies not only provides information on parasite-host interactions, but also forms the basis in the development of novel drugs and vaccines against the schistosome infection, as well as various types of autoimmune and inflammatory conditions.

Polymorphisms in Interleukin 13 Signaling and Interacting Genes Predict Advanced Fibrosis and Hepatocellular Carcinoma Development in Non-Alcoholic Steatohepatitis

Background: non-alcoholic steatohepatitis (NASH) recently headlined hepatocellular carcinoma (HCC) worldwide. This study aims to unveil the role of some unaddressed critical players that might aid in understanding, predicting, and targeting NASH and NASH-HCC. Methods: Serum interleukin 13 (IL-13) levels and single nucleotide polymorphisms (SNPs) within interleukin (IL)-13 rs20541, IL-13 receptors (IL-13R1) rs2248841, (IL-13R2) rs5946040, signal transducer activator of transcription 6 (STAT6) rs167769, yes-associated protein (YAP1) rs11225163, programmed death-ligand 1 (PD-L1) rs2282055, and programmed death-ligand 2 (PD-L2) rs7854413 genes were analyzed by qRT-PCR. Multiple stepwise regression analysis was performed on a cohort of 134 Egyptian male patients diagnosed with NASH and NASH-HCC. RESULTS: higher serum alpha-fetoprotein (AFP) and higher serum IL-13 levels were directly associated with HCC development in NASH (odds ratio (OR) 19.6 and 1.9 p < 0.01). Reversibly, the presence of the C/C genotype in STAT6 rs167769 and the C allele carrier YAP1 rs11225163 were inversely associated with HCC in NASH patients (OR 0.015 and 0.047 p < 0.01). A predictive model was formulated with 97.5% specificity, 90.9% sensitivity, and 94.8% accuracy. Moreover, higher serum IL-13 levels and the presence of PD-L2 rs7854413 C allele carriers were associated with advanced fibrosis progression in NASH patients (OR 1.432 and 3.797 p < 0.01). Serum levels of IL-13 and C/C genotype in STAT6 rs167769 significantly increased the predictive capacity of serum AFP to predict HCC in F1–F2 and in F3–F4 fibrosis grades NASH patients. Conclusion: association between serum IL-13 and PD-L2 rs7854413 polymorphism successfully predict advanced fibrosis in NASH. However, HCC development in NASH is associated with higher serum AFP, IL-13 levels, and STAT6 rs167769, YAP1 rs11225163 polymorphisms.

Ipr1 Regulation by Cyclic GMP-AMP Synthase/Interferon Regulatory Factor 3 and Modulation of Irgm1 Expression via p53

Intracellular pathogen resistance 1 (Ipr1) has been found to be a mediator to integrate cyclic GMP-AMP synthase (cGAS)-interferon regulatory factor 3 (IRF3), activated by intracellular pathogens, with the p53 pathway. Previous studies have shown the process of Ipr1 induction by various immune reactions, including intracellular bacterial and viral infections. The present study demonstrated that Ipr1 is regulated by the cGAS-IRF3 pathway during pathogenic infection. IRF3 was found to regulate Ipr1 expression by directly binding the interferon-stimulated response element motif of the Ipr1 promoter. Knockdown of Ipr1 decreased the expression of immunity-related GTPase family M member 1 (Irgm1), which plays critical roles in autophagy initiation. Irgm1 promoter characterization revealed a p53 motif in front of the transcription start site. P53 was found to participate in regulation of Irgm1 expression and IPR1-related effects on P53 stability by affecting interactions between ribosomal protein L11 (RPL11) and transformed mouse 3T3 cell double minute 2 (MDM2). Our results indicate that Ipr1 integrates cGAS-IRF3 with p53-modulated Irgm1 expression.

Hepatic Tumor Microenvironments and Effects on NK Cell Phenotype and Function

The liver is a complex organ with critical physiological functions including metabolism, glucose storage, and drug detoxification. Its unique immune profile with large numbers of cytotoxic CD8+ T cells and significant innate lymphoid population, including natural killer cells, γ δ T cells, MAIT cells, and iNKTcells, suggests an important anti-tumor surveillance role. Despite significant immune surveillance in the liver, in particular large NK cell populations, hepatic cell carcinoma (HCC) is a relatively common outcome of chronic liver infection or inflammation. The liver is also the second most common site of metastatic disease. This discordance suggests immune suppression by the environments of primary and secondary liver cancers. Classic tumor microenvironments (TME) are poorly perfused, leading to accumulation of tumor cell metabolites, diminished O2, and decreased nutrient levels, all of which impact immune cell phenotype and function. Here, we focus on changes in the liver microenvironment associated with tumor presence and how they affect NK function and phenotype.

Chronic Liver Disease in Humans Causes Expansion and Differentiation of Liver Lymphatic Endothelial Cells

Liver lymphatic vessels support liver function by draining interstitial fluid, cholesterol, fat, and immune cells for surveillance in the liver draining lymph node. Chronic liver disease is associated with increased inflammation and immune cell infiltrate. However, it is currently unknown if or how lymphatic vessels respond to increased inflammation and immune cell infiltrate in the liver during chronic disease. Here we demonstrate that lymphatic vessel abundance increases in patients with chronic liver disease and is associated with areas of fibrosis and immune cell infiltration. Using single-cell mRNA sequencing and multi-spectral immunofluorescence analysis we identified liver lymphatic endothelial cells and found that chronic liver disease results in lymphatic endothelial cells (LECs) that are in active cell cycle with increased expression of CCL21. Additionally, we found that LECs from patients with NASH adopt a transcriptional program associated with increased IL13 signaling. Moreover, we found that oxidized low density lipoprotein, associated with NASH pathogenesis, induced the transcription and protein production of IL13 in LECs both in vitro and in a mouse model. Finally, we show that oxidized low density lipoprotein reduced the transcription of PROX1 and decreased lymphatic stability. Together these data indicate that LECs are active participants in the liver, expanding in an attempt to maintain tissue homeostasis. However, when inflammatory signals, such as oxidized low density lipoprotein are increased, as in NASH, lymphatic function declines and liver homeostasis is impeded.

Solute carrier family 9, subfamily A, member 3 (SLC9A3)/sodium-hydrogen exchanger member 3 (NHE3) dysregulation and dilated intercellular spaces in patients with eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is characterized by histopathologic modifications of esophageal tissue, including eosinophil-rich inflammation, basal zone hyperplasia, and dilated intercellular spaces (DIS). The underlying molecular processes that drive the histopathologic features of EoE remain largely unexplored.

OBJECTIVE

We sought to investigate the involvement of solute carrier family 9, subfamily A, member 3 (SLC9A3) in esophageal epithelial intracellular pH (pHi) and DIS formation and the histopathologic features of EoE.

METHODS

We examined expression of esophageal epithelial gene networks associated with regulation of pHi in the EoE transcriptome of primary esophageal epithelial cells and an in vitro esophageal epithelial 3-dimensional model system (EPC2-ALI). Molecular and cellular analyses and ion transport assays were used to evaluate the expression and function of SLC9A3.

RESULTS

We identified altered expression of gene networks associated with regulation of pHi and acid-protective mechanisms in esophageal biopsy specimens from pediatric patients with EoE (healthy subjects, n = 6; patients with EoE, n = 10). The most dysregulated gene central to regulating pHi was SLC9A3. SLC9A3 expression was increased within the basal layer of esophageal biopsy specimens from patients with EoE, and expression positively correlated with disease severity (eosinophils/high-power field) and DIS (healthy subjects, n = 10; patients with EoE, n = 10). Analyses of esophageal epithelial cells revealed IL-13-induced, signal transducer and activator of transcription 6-dependent SLC9A3 expression and Na+-dependent proton secretion and that SLC9A3 activity correlated positively with DIS formation. Finally, we showed that IL-13-mediated, Na+-dependent proton secretion was the primary intracellular acid-protective mechanism within the esophageal epithelium and that blockade of SLC9A3 transport abrogated IL-13-induced DIS formation.

CONCLUSIONS

SLC9A3 plays a functional role in DIS formation, and pharmacologic interventions targeting SLC9A3 function may suppress the histopathologic manifestations in patients with EoE.

Differential Activation of Hepatic Invariant NKT Cell Subsets Plays a Key Role in Progression of Nonalcoholic Steatohepatitis

Innate immune mechanisms play an important role in inflammatory chronic liver diseases. In this study, we investigated the role of type I or invariant NKT (iNKT) cell subsets in the progression of nonalcoholic steatohepatitis (NASH). We used α-galactosylceramide/CD1d tetramers and clonotypic mAb together with intracytoplasmic cytokine staining to analyze iNKT cells in choline-deficient l-amino acid-defined (CDAA)-induced murine NASH model and in human PBMCs, respectively. Cytokine secretion of hepatic iNKT cells in CDAA-fed C57BL/6 mice altered from predominantly IL-17+ to IFN-γ+ and IL-4+ during NASH progression along with the downmodulation of TCR and NK1.1 expression. Importantly, steatosis, steatohepatitis, and fibrosis were dependent upon the presence of iNKT cells. Hepatic stellate cell activation and infiltration of neutrophils, Kupffer cells, and CD8+ T cells as well as expression of key proinflammatory and fibrogenic genes were significantly blunted in Jα18-/- mice and in C57BL/6 mice treated with an iNKT-inhibitory RAR-γ agonist. Gut microbial diversity was significantly impacted in Jα18-/- and in CDAA diet-fed mice. An increased frequency of CXCR3+IFN-γ+T-bet+ and IL-17A+ iNKT cells was found in PBMC from NASH patients in comparison with nonalcoholic fatty liver patients or healthy controls. Consistent with their in vivo activation, iNKT cells from NASH patients remained hyporesponsive to ex-vivo stimulation with α-galactosylceramide. Accumulation of plasmacytoid dendritic cells in both mice and NASH patients suggest their role in activation of iNKT cells. In summary, our findings indicate that the differential activation of iNKT cells play a key role in mediating diet-induced hepatic steatosis and fibrosis in mice and its potential involvement in NASH progression in humans.

Ziziphus spina-christi leaf extract ameliorates schistosomiasis liver granuloma, fibrosis, and oxidative stress through downregulation of fibrinogenic signaling in mice

Schistosomiasis is a widespread parasitic infection that affects humans, as well as wild and domestic animals. It ranks second after malaria, with a significant health and socio-economic impact in the developing countries. The objective of this study was to assess the anti-schistosomal impact of Ziziphus spina-christi leaf extract (ZLE) on Schistosoma mansoni-induced liver fibrosis in CD-1 Swiss male albino mice. S. mansoni infection was achieved by dipping of mouse tails in schistosomal cercariae. ZLE treatment was initiated at 46 days post-infection by administering a dose of the extract on a daily basis for 10 consecutive days. S. mansoni infection resulted in liver granuloma and fibrosis, with a drastic elevation in liver function factors, nitric oxide, and lipid peroxidation, which were associated with a reduction in glutathione content and substantial inhibition of antioxidant enzyme activities compared to those of the control. Induction of hepatic granuloma, oxidative stress, and fibrosis in the liver was controlled by ZLE administration, which also produced inhibition of matrix metalloproteinase-9, alpha-smooth muscle actin, transforming growth factor-β, and tissue inhibitors of metalloproteinases expressions. In addition, the S. mansoni-infected group exhibited an increase in Bax and caspase-3 levels and a decrease in Bcl-2 level. However, treatment with ZLE mainly mitigated apoptosis in the liver. Thus, the findings of this study revealed that Ziziphus spina-christi had anti-apoptotic, anti-fibrotic, antioxidant, and protective effects on S. mansoni-induced liver wounds. The benefits of Ziziphus spina-christi extract on S. mansoni were partly partially mediated by enhancing anti-fibrinogenic and nuclear factor erythroid 2–related factor 2 (Nrf2) pathways.

Organ and tissue fibrosis: Molecular signals, cellular mechanisms and translational implications

Fibrosis denotes excessive scarring, which exceeds the normal wound healing response to injury in many tissues. Although the extracellular matrix deposition appears unstructured disrupting the normal tissue architecture and subsequently impairing proper organ function, fibrogenesis is a highly orchestrated process determined by defined sequences of molecular signals and cellular response mechanisms. Persistent injury and parenchymal cell death provokes tissue inflammation, macrophage activation and immune cell infiltration. The release of biologically highly active soluble mediators (alarmins, cytokines, chemokines) lead to the local activation of collagen producing mesenchymal cells such as pericytes, myofibroblasts or Gli1 positive mesenchymal stem cell-like cells, to a transition of various cell types into myofibroblasts as well as to the recruitment of fibroblast precursors. Clinical observations and experimental models highlighted that fibrosis is not a one-way road. Specific mechanistic principles of fibrosis regression involve the resolution of chronic tissue injury, the shift of inflammatory processes towards recovery, deactivation of myofibroblasts and finally fibrolysis of excess matrix scaffold. The thorough understanding of common principles of fibrogenic molecular signals and cellular mechanisms in various organs - such as liver, kidney, lung, heart or skin - is the basis for developing improved diagnostics including biomarkers or imaging techniques and novel antifibrotic therapeutics.

Low IL-6, IL-10, and TNF-α and High IL-13 Cytokine Levels Are Associated with Severe Hepatic Fibrosis in Schistosoma mansoni Chronically Exposed Individuals

Several studies have attributed the etiopathogenesis of chronic Schistosoma mansoni related hepatic fibrosis to unregulated immune responses against trapped parasite ova in the host. However, there is limited data on immune profiles associated with varying degrees of the disease in a population under chronic exposure to the parasite. We therefore investigated the role of selected T-helper (Th)1, Th2, and Th17 cytokines in relation to hepatic fibrosis severity among individuals resident in a hyper-Schistosoma mansoni endemic region of Western Zambia. Two hundred and forty-four S. mansoni infected individuals with and without fibrosis were analysed for cytokine profiles. Based on hepatic fibrosis stage as determined by ultrasound, participants were categorized into Group 0, Group I, Group II, and Group III. Cytokines were measured in S. mansoni egg stimulated whole blood culture supernatants using the BD Cytometric Bead Array kits. Compared to the nonfibrotic group, participants in the severe hepatic fibrotic group produced less interleukin- (IL-) 6, IL-10, and tumour necrosis factor-alpha (TNF-α). On the other hand, IL-13 was significantly elevated in this group compared to the nonfibrotic group (p < 0.001). Our results suggest that low IL-6, IL-10, and TNF-α and high IL-13 levels may influence S. mansoni disease progression.

Molecular targets of dietary phytochemicals for possible prevention and therapy of uterine fibroids: Focus on fibrosis

Uterine fibroids (myomas or leiomyomas) are common benign tumors of reproductive aged women. Fibroids are clinically apparent in 20-50% of women, and cause abnormal uterine bleeding, abdominal pain and discomfort, pregnancy complications and infertility. Unfortunately, limited numbers of medical treatment are available but no effective preventive strategies exist. Moreover, the benefits of medical treatments are tempered by lack of efficacy or serious adverse side effects. Fibrosis has recently been recognized as a key pathological event in leiomyoma development and growth. It is defined by the excessive deposition of extracellular matrix (ECM). ECM plays important role in making bulk structure of leiomyoma, and ECM-rich rigid structure is believed to be a cause of abnormal bleeding and pelvic pain/pressure. Dietary phytochemicals are known to regulate fibrotic process in different biological systems, and being considered as potential tool to manage human health. At present, very few dietary phytochemicals have been studied in uterine leiomyoma, and they are mostly known for their antiproliferative effects. Therefore, in this review, our aim was to introduce some dietary phytochemicals that could target fibrotic processes in leiomyoma. Thus, this review could serve as useful resource to develop antifibrotic drugs for possible prevention and treatment of uterine fibroids.

Corilagin Counteracts IL-13Rα1 Signaling Pathway in Macrophages to Mitigate Schistosome Egg-Induced Hepatic Fibrosis

The IL-13Rα1 signaling pathway and M2 macrophages play crucial roles in schistosome egg-induced hepatic fibrosis via the expression of pro-fibrotic molecules. This study aims to investigate the inhibitory effect and mechanism of action of corilagin on schistosome egg-induced hepatic fibrosis via the IL-13Rα1 signaling pathway in M2 macrophages in vitro and in vivo. The mRNA and protein expression of IL-13Rα1, PPARγ, KLF4, SOCS1, STAT6, p-STAT6, and TGF-β was measured in vitro with corilagin treatment after IL-13 stimulation and in vivo corilagin treatment after effectively killing the adult schistosomes in schistosome-infected mice. Histological analysis of liver tissue was assessed for the degree of hepatic fibrosis. The results revealed that corilagin significantly reduced the expression of PPARγ, KLF4, SOCS1, p-STAT6, and TGF-β compared with model group and praziquantel administration (p < 0.01 or p < 0.05) in vivo and in vitro, which indicated a strong inhibitory effect of corilagin on IL-13Rα1 signaling pathway. As well, the inhibitory effect of corilagin showed a significant dose-dependence (p < 0.05). The area of fibrosis and distribution of M2 macrophages in mouse liver tissue were reduced significantly and dose-dependently with corilagin treatment compared to model group or praziquantel administration (p < 0.01 or p < 0.05), indicating that corilagin suppressed IL-13Rα1 signaling pathway and M2 macrophage polarization effectively in vivo. Furthermore, the anti-fibrogenic effect persisted even when IL-13Rα1 was up- or down-regulated in vitro. In conclusion, corilagin can suppress schistosome egg-induced hepatic fibrosis via inhibition of M2 macrophage polarization in the IL-13Rα1 signaling pathway.

Bone marrow-derived monocyte infusion improves hepatic fibrosis by decreasing osteopontin, TGF-β1, IL-13 and oxidative stress

AIM

To evaluate the therapeutic effects of bone marrow-derived CD11b⁺CD14⁺ monocytes in a murine model of chronic liver damage.

METHODS

Chronic liver damage was induced in C57BL/6 mice by administration of carbon tetrachloride and ethanol for 6 mo. Bone marrow-derived monocytes isolated by immunomagnetic separation were used for therapy. The cell transplantation effects were evaluated by morphometry, biochemical assessment, immunohistochemistry and enzyme-linked immunosorbent assay.

RESULTS

CD11b⁺CD14⁺ monocyte therapy significantly reduced liver fibrosis and increased hepatic glutathione levels. Levels of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin (IL)-6 and IL-1β, in addition to pro-fibrotic factors, such as IL-13, transforming growth factor-β1 and tissue inhibitor of metalloproteinase-1 also decreased, while IL-10 and matrix metalloproteinase-9 increased in the monocyte-treated group. CD11b⁺CD14⁺ monocyte transplantation caused significant changes in the hepatic expression of α-smooth muscle actin and osteopontin.

CONCLUSION

Monocyte therapy is capable of bringing about improvement of liver fibrosis by reducing oxidative stress and inflammation, as well as increasing anti-fibrogenic factors.

Corilagin ameliorates schistosomiasis hepatic fibrosis through regulating IL-13 associated signal pathway in vitro and in vivo

Interleukin (IL)-13-associated signal pathway plays an important role in schistosomiasis hepatic fibrosis. In this study we tried to investigate the effects of corilagin to ameliorate schistosomiasis hepatic fibrosis through regulating IL-13-associated signal pathway in vitro and in vivo. Cellular model was set up with hepatic stellate cells-T6 cells stimulated by rIL-13 and male Balb/c mice were infected with Schistosoma japonicum cercariaeas as animal model. Liver histological changes were observed with haematoxylin and eosin staining. Masson staining was employed to observe the change of egg granulomas. Expression of Col (collagen) and Col III were examined with Immunohistochemistry. Western bolt was employed to detect the JAK-1 and IL13Rα1 proteins. The mRNA expression of Col I, Col III, IL-13, JAK-1 and IL13Rα1 were tested by quantitative polymerase chain reaction. As a result, less inflammatory changes were found in all corilagin groups compared with model group and praziquantel group. The mRNA levels of Col I, Col III, IL-13, JAK-1 and IL13Rα1 were significantly decreased after corilagin intervention (P < 0·01). JAK-1 and IL-13Rα1 protein levels were also greatly decreased in the corilagin groups (P < 0·01). In conclusion, corilagin could ameliorate schistosomiasis hepatic fibrosis by down-regulating the expression of IL-13 and signal molecules in IL-13 pathway.

Strategies targeting the IL-4/IL-13 axes in disease

IL-4 and IL-13 are pleiotropic Th2 cytokines produced by a wide variety of different cell types and responsible for a broad range of biology and functions. Physiologically, Th2 cytokines are known to mediate host defense against parasites but they can also trigger disease if their activities are dysregulated. In this review we discuss the rationale for targeting the IL-4/IL-13 axes in asthma, atopic dermatitis, allergic rhinitis, COPD, cancer, inflammatory bowel disease, autoimmune disease and fibrotic disease as well as evaluating the associated clinical data derived from blocking IL-4, IL-13 or IL-4 and IL-13 together.

The role of IL-17 signaling in regulation of the liver-brain axis and intestinal permeability in Alcoholic Liver Disease

Alcoholic liver disease (ALD) progresses from a normal liver, to steatosis, steatohepatitis, fibrosis and hepatocellular carcinoma (HCC). Despite intensive studies, the pathogenesis of ALD is poorly understood, in part due to a lack of suitable animal models which mimic the stages of ALD progression. Furthermore, the role of IL-17 in ALD has not been evaluated. We and others have recently demonstrated that IL-17 signaling plays a critical role in development of liver fibrosis and cancer. Here we summarize the most recent evidence supporting the role of IL-17 in ALD. As a result of a collaborative effort of Drs. Karin, Gao, Tsukamoto and Kisseleva, we developed several improved models of ALD in mice: 1) chronic-plus-binge model that mimics early stages of steatohepatitis, 2) intragastric ethanol feeding model that mimics alcoholic steatohepatitis and fibrosis, and 3) diethylnitrosamine (DEN)+alcohol model that mimics alcoholic liver cancer. These models might provide new insights into the mechanism of IL-17 signaling in ALD and help identify novel therapeutic targets.