Interleukin-1 Receptor Antagonist Modulates Liver Inflammation and Fibrosis in Mice in a Model-Dependent Manner

Homeobox B4 optimizes the therapeutic effect of bone marrow mesenchymal stem cells on endotoxin-associated acute lung injury in rats

BACKGROUND

Alveolar capillary endothelial cell (EC) injury has a pivotal role in driving acute respiratory distress syndrome (ARDS) progression and maintaining endothelial homeostasis. A previous ex vivo study revealed that overexpression of homeobox B4 (HOXB4) in bone marrow mesenchymal stem cells (BMSCs) enhanced protection against lipopolysaccharide (LPS)-induced EC injury by activating the Wnt/β-catenin pathway. This in vivo study was performed to verify whether BMSCs overexpressing HOXB4 exert similar protective effects on LPS-induced acute lung injury (ALI) in an animal model.

METHODS

The ALI rat model was established by intraperitoneal injection of LPS. Wildtype BMSCs or BMSCs overexpressing HOXB4 were then injected via the tail vein. The lung characteristics of rats were visualized by computed tomography. Lung histopathological characteristics and collagen deposition were assessed by hematoxylin-eosin and Masson's staining, respectively, which were combined with the lung wet/dry ratio and proinflammatory factor levels in bronchoalveolar lavage fluid to further evaluate therapeutic effects. Expression of β-catenin and VE-cadherin was assessed by western blotting and immunofluorescence.

RESULTS

Compared with wildtype BMSCs, overexpression of HOXB4 optimized the therapeutic effects of BMSCs, which manifested as improvements in lung exudation and histopathological features, reduced lung collagen deposition, amelioration of lung permeability, attenuation of lung inflammation, and enhanced expression of β-catenin and VE-cadherin proteins.

CONCLUSIONS

HOXB4-overexpressing BMSCs optimized the protective effect against LPS-induced ALI by partially activating Wnt/β-catenin signaling.

NLRP3 inflammasome activation promotes liver inflammation and fibrosis in experimental biliary atresia

BACKGROUND

Biliary atresia (BA) is characterized by a progressive fibroinflammatory cholangiopathy in early infants with unknown etiology. Although innate immune disorder is involved in its mechanism, role of NLRP3 inflammasome in BA remains largely undefined.

AIM

To explore the role of NLRP3 inflammasome in BA.

METHODS

The expressions of NLRP3 inflammasome-related genes were determined in BA patients. Role of NLRP3 inflammasome was evaluated using MCC950 in experimental BA. Furthermore, gadolinium chloride, a macrophage scavenger, was applied to validate the inflammasome's cellular localization. Finally, the effects of NLRP3 inflammasome activation on liver fibrosis were explored in vivo and vitro in experimental BA.

RESULTS

The components of NLRP3 inflammasome were up-regulated in BA patients. Inflammasome-related genes showed positively correlated with liver inflammation and fibrosis in BA patients. In experimental BA, inflammasome-related genes were up-regulated, and their expressions were inhibited by MCC950, which promoted mice growth, protected liver function, alleviated obstructive jaundice, inhibited liver inflammation, and reduced serum IL-1β level. NLRP3 inflammasome was expressed in macrophages, and macrophage elimination exerted the same protective roles as MCC950 did in BA. Additionally, NLRP3 inflammasome activation promoted liver fibrosis in experimental BA.

CONCLUSIONS

NLRP3 inflammasome activation in macrophages promoted liver inflammation and fibrosis in experimental BA.

Vitamin D Receptor Activation Reduces Hepatic Inflammation via Enhancing Macrophage Autophagy in Cholestatic Mice

Macrophage autophagy dysfunction aggravates liver injury by activating inflammasomes, which can cleave pro-IL-1β to its active, secreted form. We investigated whether the vitamin D/vitamin D receptor (VDR) axis could up-regulate macrophage autophagy function to inhibit the activation of inflammasome-dependent IL-1β during cholestasis. Paricalcitol (PAL; VDR agonist) was intraperitoneally injected into bile duct-ligated mice for 5 days. Up-regulation of VDR expression by PAL reduced liver injury by reducing the oxidative stress-induced inflammatory reaction in macrophages. Moreover, PAL inhibited inflammasome-dependent IL-1β generation. Mechanistically, the knockdown of VDR increased IL-1β generation, whereas VDR overexpression exerted the opposite effect following tert-butyl hydroperoxide treatment. The inflammasome antagonist glyburide, the caspase-1-specific inhibitor YVAD, and the reactive oxygen species (ROS) scavenger N-acetyl-l-cysteine (NAC) blocked the increase in Vdr shRNA-induced IL-1β production. Interestingly, up-regulation of VDR also enhanced macrophage autophagy. Autophagy reduction impaired the up-regulation of VDR-inhibited macrophage inflammasome-generated IL-1β, whereas autophagy induction showed a synergistic effect with VDR overexpression through ROS-p38 mitogen-activated protein kinase (MAPK) pathway. This result was confirmed by p38 MAPK inhibitor, MAPK activator, and ROS inhibitor NAC. Collectively, PAL triggered macrophage autophagy by suppressing activation of the ROS-p38 MAPK pathway, which, in turn, suppressed inflammasome-generated cleaved, active forms of IL-1β, eventually leading to reduced inflammation. Thus, triggering the VDR may be a potential target for the anti-inflammatory treatment of cholestatic liver disease.

The Novel Tetra-Specific Drug C-192, Conjugated Using UniStac, Alleviates Non-Alcoholic Steatohepatitis in an MCD Diet-Induced Mouse Model

Non-alcoholic steatohepatitis (NASH) is a complex disease resulting from chronic liver injury associated with obesity, type 2 diabetes, and inflammation. Recently, the importance of developing multi-target drugs as a strategy to address complex diseases such as NASH has been growing; however, their manufacturing processes remain time- and cost-intensive and inefficient. To overcome these limitations, we developed UniStac, a novel enzyme-mediated conjugation platform for multi-specific drug development. UniStac demonstrated high conjugation yields, optimal thermal stabilities, and robust biological activities. We designed a tetra-specific compound, C-192, targeting glucagon-like peptide 1 (GLP-1), glucagon (GCG), fibroblast growth factor 21 (FGF21), and interleukin-1 receptor antagonist (IL-1RA) simultaneously for the treatment of NASH using UniStac. The biological activity and treatment efficacy of C-192 were confirmed both in vitro and in vivo using a methionine-choline-deficient (MCD) diet-induced mouse model. C-192 exhibited profound therapeutic efficacies compared to conventional drugs, including liraglutide and dulaglutide. C-192 significantly improved alanine transaminase levels, triglyceride accumulation, and the non-alcoholic fatty liver disease activity score. In this study, we demonstrated the feasibility of UniStac in creating multi-specific drugs and confirmed the therapeutic potential of C-192, a drug that integrates multiple mechanisms into a single molecule for the treatment of NASH.

NLRP3 inflammasome in hepatic diseases: A pharmacological target

The NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome pathway is mainly responsible for the activation and release of a cascade of proinflammatory mediators that contribute to the development of hepatic diseases. During alcoholic liver disease development, the NLRP3 inflammasome pathway contributes to the maturation of caspase-1, interleukin (IL)-1β, and IL-18, which induce a robust inflammatory response, leading to fibrosis by inducing profibrogenic hepatic stellate cell (HSC) activation. Substantial evidence demonstrates that nonalcoholic fatty liver disease (NAFLD) progresses to nonalcoholic steatohepatitis (NASH) via NLRP3 inflammasome activation, ultimately leading to fibrosis and hepatocellular carcinoma (HCC). Activation of the NLRP3 inflammasome in NASH can be attributed to several factors, such as reactive oxygen species (ROS), gut dysbiosis, leaky gut, which allow triggers such as cardiolipin, cholesterol crystals, endoplasmic reticulum stress, and uric acid to reach the liver. Because inflammation triggers HSC activation, the NLRP3 inflammasome pathway performs a central function in fibrogenesis regardless of the etiology. Chronic hepatic activation of the NLRP3 inflammasome can ultimately lead to HCC; however, inflammation also plays a role in decreasing tumor growth. Some data indicate that NLRP3 inflammasome activation plays an important role in autoimmune hepatitis, but the evidence is scarce. Most researchers have reported that NLRP3 inflammasome activation is essential in liver injury induced by a variety of drugs and hepatotropic virus infection; however, few reports indicate that this pathway can play a beneficial role by inducing liver regeneration. Modulation of the NLRP3 inflammasome appears to be a suitable strategy to treat liver diseases.

Fucoxanthin exert dose-dependent antifibrotic and anti-inflammatory effects on CCl4-induced liver fibrosis

The lack of an effective non-surgical liver fibrosis treatment is a major problem in hepatology. Fucoxanthin is a marine xanthophyll that exhibits anti-inflammatory, antioxidant, and hepatoprotective properties, thereby indicating its potential effectiveness in the treatment of liver fibrosis. The study aims to investigate the antifibrotic and anti-inflammatory effects of fucoxanthin and its main mechanisms on carbon tetrachloride (CCl4)-induced liver fibrosis in 50 outbred ICR/CD1 mice. 2 μl/g of CCl4 were injected intraperitoneally 2 times a week for 6 weeks. Fucoxanthin (5, 10, 30 mg/kg) was administered via gavage. Liver histopathology was evaluated by Hematoxylin-Eosin (H&E) and Sirius Red staining using the METAVIR scale. The immunohistochemical method was used to determine the number of CD45 and α-smooth muscle actin (α-SMA) positive cells, and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), matrix metalloproteinase-9 (MMP-9), and α-SMA positive areas. Using enzyme immunoassays, procollagen 1 (COL1A1), transforming growth factor-β (TGF-β), and hepatocyte growth factor (HGF) were determined in homogenate, and interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) were determined in blood serum. Serum alanine aminotransferase (ALT) and aspartate transaminase (AST) activity, albumin (ALB), and total bilirubin (Tbil) levels are determined by biochemical assays. Fucoxanthin significantly reduced the severity of liver fibrosis, profibrogenic markers, inflammatory infiltration, and pro-inflammatory cytokines. In summary, we confirmed that fucoxanthin has a dose-dependent antifibrotic effect on CCl4-induced liver fibrosis. We found that the anti-inflammatory effect of fucoxanthin is related to the inhibition of IL-1β and TNF-α synthesis, as well as the decrease in the number of leukocytes in the injured liver.

Unravelling the anti-inflammatory and antioxidant effects of standardized green and black caffeinated coffee, tea, and their mixtures in an obese male rat model: Insights from biochemical, metabolomic, and histopathological analyses

Obesity is one of the major metabolic syndrome risk factors upon which altered metabolic pathways follow. This study aimed to discern altered metabolic pathways associated with obesity and to pinpoint metabolite biomarkers in serum of obese rats fed on high fructose diet using metabolomics. Further, the effect of standardized green versus black caffeinated aqueous extracts (tea and coffee) in controlling obesity and its comorbidities through monitoring relevant serum biomarkers viz. Leptin, adiponectin, spexin, malondialdehyde, total antioxidant capacity. Liver tissue oxidative stress (catalase, super oxide dismutase and glutathione) and inflammation (IL-1β and IL-6) markers were assessed for green coffee and its mixture with green tea. Results revealed improvement of all parameters upon treatments with more prominence for those treated with green caffeinated extract (coffee and tea) especially in mixture. Upon comparing with obese rat group, the green mixture of coffee and tea exhibited anti-hyperlipidemic action through lowering serum triglycerides by 35.0% and elevating high density lipoprotein by 71.0%. Black tea was likewise effective in lowering serum cholesterol and low density lipoprotein by 28.0 and 50.6%, respectively. GC-MS- based metabolomics of rat serum led to the identification of 34 metabolites with obese rat serum enriched in fatty acids (oleamide).

Pyroptosis in renal inflammation and fibrosis: current knowledge and clinical significance

Pyroptosis is a novel inflammatory form of regulated cell death (RCD), characterized by cell swelling, membrane rupture, and pro-inflammatory effects. It is recognized as a potent inflammatory response required for maintaining organismal homeostasis. However, excessive and persistent pyroptosis contributes to severe inflammatory responses and accelerates the progression of numerous inflammation-related disorders. In pyroptosis, activated inflammasomes cleave gasdermins (GSDMs) and generate membrane holes, releasing interleukin (IL)-1β/18, ultimately causing pyroptotic cell death. Mechanistically, pyroptosis is categorized into caspase-1-mediated classical pyroptotic pathway and caspase-4/5/11-mediated non-classical pyroptotic pathway. Renal fibrosis is a kidney disease characterized by the loss of structural and functional units, the proliferation of fibroblasts and myofibroblasts, and extracellular matrix (ECM) accumulation, which leads to interstitial fibrosis of the kidney tubules. Histologically, renal fibrosis is the terminal stage of chronic inflammatory kidney disease. Although there is a multitude of newly discovered information regarding pyroptosis, the regulatory roles of pyroptosis involved in renal fibrosis still need to be fully comprehended, and how to improve clinical outcomes remains obscure. Hence, this review systematically summarizes the novel findings regarding the role of pyroptosis in the pathogenesis of renal fibrosis and discusses potential biomarkers and drugs for anti-fibrotic therapeutic strategies.

Interleukin-18 signaling promotes activation of hepatic stellate cells in mouse liver fibrosis

BACKGROUND AND AIMS

Nucleotide-binding oligomerization domain-like receptor-family pyrin domain-containing 3 (NLRP3) inflammasome activation has been shown to result in liver fibrosis. Mechanisms and downstream signaling remain incompletely understood. Here, we studied the role of IL-18 in hepatic stellate cells (HSCs), and its impact on liver fibrosis.

APPROACH AND RESULTS

We observed significantly increased serum levels of IL-18 (128.4 pg/ml vs. 74.9 pg/ml) and IL-18 binding protein (BP; 46.50 ng/ml vs. 15.35 ng/ml) in patients with liver cirrhosis compared with healthy controls. Single cell RNA sequencing data showed that an immunoregulatory subset of murine HSCs highly expresses Il18 and Il18r1 . Treatment of cultured primary murine HSC with recombinant mouse IL-18 accelerated their transdifferentiation into myofibroblasts. In vivo , IL-18 receptor-deficient mice had reduced liver fibrosis in a model of fibrosis induced by HSC-specific NLRP3 overactivation. Whole liver RNA sequencing analysis from a murine model of severe NASH-induced fibrosis by feeding a choline-deficient, L-amino acid-defined, high fat diet showed that genes related to IL-18 and its downstream signaling were significantly upregulated, and Il18-/- mice receiving this diet for 10 weeks showed protection from fibrotic changes with decreased number of alpha smooth muscle actin-positive cells and collagen deposition. HSC activation triggered by NLRP3 inflammasome activation was abrogated when IL-18 signaling was blocked by its naturally occurring antagonist IL-18BP. Accordingly, we observed that the severe inflammatory phenotype associated with myeloid cell-specific NLRP3 gain-of-function was rescued by IL-18BP.

CONCLUSIONS

Our study highlights the role of IL-18 in the development of liver fibrosis by its direct effect on HSC activation identifying IL-18 as a target to treat liver fibrosis.

Theroleofinterleukin-1familyinfibroticdiseases

Fibrosis refers to the phenomenon that fibrous connective tissues are increased and parenchymal cells are decreased in organs or tissues such as lung, heart, liver, kidney, skin and so on. It usually occurs at the late stage of repair of chronic or recurrent tissue damage. Fibrotic disease is the main factor for the morbidity and mortality of all tissues and organ systems. Long-term fibrosis can lead to organ and tissue dysfunction and even failure. Interleukin -1 family cytokines are a series of classical inflammatory factors and involved in the occurrence and development process of multiple fibrotic diseases, its biological function, relationship with diseases and application are more and more favored by scientists from various countries. So far, 11 cytokines and 10 receptors of IL-1 family have been identified. In this paper, the cytokines, receptors, signaling pathways and biological functions of IL-1 family are summarized, and the correlation with fibrosis diseases is analyzed.

An update on animal models of liver fibrosis

The development of liver fibrosis primarily determines quality of life as well as prognosis. Animal models are often used to model and understand the underlying mechanisms of human disease. Although organoids can be used to simulate organ development and disease, the technology still faces significant challenges. Therefore animal models are still irreplaceable at this stage. Currently, in vivo models of liver fibrosis can be classified into five categories based on etiology: chemical, dietary, surgical, transgenic, and immune. There is a wide variety of animal models of liver fibrosis with varying efficacy, which have different implications for proper understanding of the disease and effective screening of therapeutic agents. There is no high-quality literature recommending the most appropriate animal models. In this paper, we will describe the progress of commonly used animal models of liver fibrosis in terms of their development mechanisms, applications, advantages and disadvantages, and recommend appropriate animal models for different research purposes.

Therapeutic Perspectives of IL1 Family Members in Liver Diseases: An Update

Interleukin (IL) 1 superfamily members are a cornerstone of a variety of inflammatory processes occurring in various organs including the liver. Progression of acute and chronic liver diseases regardless of etiology depends on the stage of hepatocyte damage, the release of inflammatory cytokines and disturbances in gut microbiota. IL1 cytokines and receptors can have pro- or anti-inflammatory roles, even dual functionalities conditioned by the microenvironment. Developing novel therapeutic strategies to block the IL1/IL1R signaling pathways seems like a reasonable option. This mode of action is now exploited by anakinra and canakinumab, which are used to treat different inflammatory illnesses, and studies in liver diseases are on the way. In this mini review, we have focused on the IL1 superfamily members, given their crucial role in liver inflammation diseases, specifically discussing their potential role in developing new treatment strategies.

Glucose Increases Hepatic Mitochondrial Antioxidant Enzyme Activities in Insulin Resistant Rats Following Chronic Angiotensin Receptor Blockade

Non-alcoholic fatty liver disease (NAFLD) affects up to 20% of the world’s population. Overactivation of the angiotensin receptor type 1 (AT1) contributes to metabolic dysfunction and increased oxidant production, which are associated with NAFLD and impaired hepatic lipid metabolism. Nuclear factor erythroid-2-related factor 2 (Nrf2) regulates the expression of antioxidant phase II genes by binding to the antioxidant response element (ARE); however, the mechanisms by which AT1 contributes to this pathway during the progression of NAFLD remain unresolved. To investigate hepatic Nrf2 response to a hyperglycemic challenge, we studied three groups of rats (male, 10-weeks-old): (1) untreated, lean Long Evans Tokushima Otsuka (LETO), (2) untreated, obese Otsuka Long Evans Tokushima Fatty (OLETF), and (3) OLETF + angiotensin receptor blocker (OLETF + ARB; 10 mg olmesartan/kg/d × 6 weeks). Livers were collected after overnight fasting (T0; baseline), and 1 h and 2 h post-oral glucose load. At baseline, chronic AT1 blockade increased nuclear Nrf2 content, reduced expression of glutamate-cysteine ligase catalytic (GCLC) subunit, glutathione peroxidase 1 (GPx1), and superoxide dismutase 2 (SOD2), mitochondrial catalase activity, and hepatic 4-hydroxy-2-nonenal (4-HNE) content. The expression of hepatic interleukin-1 beta (IL-1β) and collagen type IV, which are associated with liver fibrosis, were decreased with AT1 blockade. Glucose increased Nrf2 translocation in OLETF but was reduced in ARB, suggesting that glucose induces the need for antioxidant defense that is ameliorated with ARB. These results suggest that overactivation of AT1 promotes oxidant damage by suppressing Nrf2 and contributing to hepatic fibrosis associated with NAFLD development.

The combination of Lonicerae Japonicae Flos and Forsythiae Fructus herb-pair alleviated inflammation in liver fibrosis

Objective: To explore the active components and epigenetic regulation mechanism underlying the anti-inflammatory effects of Lonicerae Japonicae Flos and Forsythiae Fructus herb-pair (LFP) in carbon tetrachloride (CCl₄)-induced rat liver fibrosis.

Methods: The main active ingredients and disease-related gene targets of LFP were determined using TCMSP and UniProt, and liver fibrosis disease targets were screened in the GeneCards database. A network was constructed with Cytoscape 3.8.0 and the STRING database, and potential protein functions were analyzed using bioinformatics analysis. Based on these analyses, we determined the main active ingredients of LFP and evaluated their effects in a CCl₄-induced rat liver fibrosis model. Serum biochemical indices were measured using commercial kits, hepatocyte tissue damage and collagen deposition were evaluated by histopathological studies, and myofibroblast activation and inflammation were detected by reverse transcription-polymerase chain reaction (RT-PCR) and western blotting. High-performance liquid chromatography-mass spectrometry was performed to determine the levels of homocysteine, reduced glutathione, and oxidized glutathione, which are involved in inflammation and oxidative stress.

Results: The main active components of LFP were quercetin, kaempferol, and luteolin, and its main targets were α-smooth muscle actin, cyclooxygenase-2, formyl-peptide receptor-2, prostaglandin-endoperoxide synthase 1, nuclear receptor coactivator-2, interleukinβ, tumor necrosis factor α, CXC motif chemokine ligand 14, and transforming growth factor β1. A combination of quercetin, kaempferol, and luteolin alleviated the symptoms of liver fibrosis.

Conclusion: The results of this study support the role of LFP in the treatment of liver fibrosis, and reveal that LFP reduces collagen formation, inflammation, and oxidative stress. This study suggests a potential mechanism of action of LFP in the treatment of liver fibrosis.

The Bioinformatic Study Uncovers Probable Critical Genes Involved in the Pathophysiology of Biliary Atresia

Background

Biliary atresia (BA) is an uncommon illness that causes the bile ducts outside and within the liver to become clogged in babies. If left untreated, the cholestasis causes increasing conjugated hyperbilirubinemia, cirrhosis, and hepatic failure. BA has a complicated aetiology, and the mechanisms that drive its development are unknown. The objective of this study was to show the role of probable critical genes involved in the pathophysiology of biliary atresia.

Methods

We utilised the public Gene Expression Omnibus (GEO) microarray expression profiling dataset GSE46960 to find differentially expressed genes (DEGs) in 64 biliary atresia newborns, 14 infants with various causes of intrahepatic cholestasis, and 7 deceased-donor children as control subjects in our study. The relevant information was looked into. The important modules were identified after functional enrichment, GO and KEGG pathway analyses, protein-protein interaction (PPI) network analyses, and GSEA analysis.

Results

The differential expression analysis revealed a total of 22 elevated genes. To further understand the biological activities of the DEGs, we run functional enrichment analyses on them. Meanwhile, KEGG analysis has revealed significant enrichment of pathways involved in activating cross-talking with inflammation and fibrosis in BA. SERPINE1, THBS1, CCL2, MMP7, CXCL8, EPCAM, VCAN, ITGA2, AREG, and HAS2, which may play a significant regulatory role in the pathogenesis of BA, were identified by PPI studies.

Conclusion

Our findings suggested 10 hub genes and probable mechanisms of BA in the current study through bioinformatic analysis.

Host cell proteins modulated upon Toxoplasma infection identified using proteomic approaches: a molecular rationale

Toxoplasma gondii is a pathogenic protozoan parasite belonging to the apicomplexan phylum that infects the nucleated cells of warm-blooded hosts leading to an infectious disease known as toxoplasmosis. Apicomplexan parasites such as T. gondii can display different mechanisms to control or manipulate host cells signaling at different levels altering the host subcellular genome and proteome. Indeed, Toxoplasma is able to modulate host cell responses (especially immune responses) during infection to its advantage through both structural and functional changes in the proteome of different infected cells. Consequently, parasites can transform the invaded cells into a suitable environment for its own replication and the induction of infection. Proteomics as an applicable tool can identify such critical proteins involved in pathogen (Toxoplasma)-host cell interactions and consequently clarify the cellular mechanisms that facilitate the entry of pathogens into host cells, and their replication and transmission, as well as the central mechanisms of host defense against pathogens. Accordingly, the current paper reviews several proteins (identified using proteomic approaches) differentially expressed in the proteome of Toxoplasma-infected host cells (macrophages and human foreskin fibroblasts) and tissues (brain and liver) and highlights their plausible functions in the cellular biology of the infected cells. The identification of such modulated proteins and their related cell impact (cell responses/signaling) can provide further information regarding parasite pathogenesis and biology that might lead to a better understanding of therapeutic strategies and novel drug targets.

GC-MS Profile of Hua-Feng-Dan and RNA-Seq Analysis of Induced Adaptive Responses in the Liver

Background: Hua-Feng-Dan is a patent Chinese medicine for stroke recovery and various diseases. This study used GC-MS to profile its ingredients and RNA-Seq to analyze the induced adaptive response in the liver. Methods: Hua-Feng-Dan was subjected to steam distillation and solvent extraction, followed by GC-MS analysis. Mice were orally administered Hua-Feng-Dan and its "Guide drug" Yaomu for 7 days. Liver pathology was examined, and total RNA isolated for RNA-Seq, followed by bioinformatic analysis and quantitative real-time PCR (qPCR). Results: Forty-four volatile and fifty liposoluble components in Hua-Feng-Dan were profiled and analyzed by the NIST library and their concentrations quantified. The major components (>1%) in volatile (5) and liposoluble (10) were highlighted. Hua-Feng-Dan and Yaomu at hepatoprotective doses did not produce liver toxicity as evidenced by histopathology and serum enzyme activities. GO Enrichment revealed that Hua-Feng-Dan affected lipid homeostasis, protein folding, and cell adhesion. KEGG showed activated cholesterol metabolism, bile secretion, and PPAR signaling pathways. Differentially expressed genes (DEGs) were identified by DESeq2 with p < 0.05 compared to controls. Hua-Feng-Dan produced more DEGs than Yaomu. qPCR on selected genes largely verified RNA-Seq results. Ingenuity Pathways Analysis of the upstream regulator revealed activation of MAPK and adaptive responses by Hua-Feng-Dan, and Yaomu was less effective. Hua-Feng-Dan-induced DEGs were highly correlated with the Gene Expression Omnibus database of chemical-induced adaptive transcriptome changes in the liver. Conclusion: GC-MS primarily profiled volatile and liposoluble components in Hua-Feng-Dan. Hua-Feng-Dan at the hepatoprotective dose did not produce liver pathological changes but induced metabolic and signaling pathway activations. The effects of Hua-Feng-Dan on liver transcriptome changes point toward induced adaptive responses to program the liver to produce hepatoprotective effects.

A promising antifibrotic drug, pyridoxamine attenuates thioacetamide-induced liver fibrosis by combating oxidative stress, advanced glycation end products, and balancing matrix metalloproteinases

Liver fibrosis is a common chronic hepatic disease. This study was done to examine the effect of pyridoxamine against thioacetamide-induced hepatic fibrosis. Animals were divided into four groups (1) control group; (2) Thioacetamide group (200 mg/kg, i.p.) twice a week for eight weeks; (3) Pyridoxamine-treated group treated with pyridoxamine (100 mg/kg/day, i.p.) for eight weeks; (4) Thioacetamide and pyridoxamine group, in which pyridoxamine was given (100 mg/kg/day, i.p.) during thioacetamide injections. Thioacetamide treatment resulted in hepatic dysfunction manifested by increased serum levels of bilirubin, gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). Oxidative stress was noted by increased hepatic lipid peroxidation and decreased glutathione (GSH). Increased concentrations of total nitrite/nitrate, advanced glycation end products (AGEs), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), matrix metalloproteinases (MMP-2&9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were noticed in hepatic tissues. Immunostaining sections also revealed overexpression of MMP-2, MMP-9 and collagen IV. Liver fibrosis was confirmed by severe histopathological changes. Pyridoxamine improved the assessed parameters. Moreover, histopathological and immunohistological studies supported the ability of pyridoxamine to reduce liver fibrosis. The findings of the present study provide evidence that pyridoxamine is a novel target for the treatment of liver fibrosis.

Immune Mechanisms and Related Targets for the Treatment of Fibrosis in Various Organs

Inflammation and fibrosis are two inter-related disease pathologies with several overlapping components. Three specific cell types, macrophages, T helper cells and myofibroblasts, each play important roles in regulating both processes. Following tissue injury, an inflammatory stimulus is often necessary to initiate tissue repair, where cytokines released from infiltrating and resident immune and inflammatory cells stimulate the proliferation and activation of extracellular matrix-producing myofibroblasts. However, persistent tissue injury drives an inappropriate pro-fibrotic response. Additionally, activated myofibroblasts can take on the role of traditional antigen-presenting cells, secrete pro-inflammatory cytokines, and recruit inflammatory cells to fibrotic foci, amplifying the fibrotic response in a vicious cycle. Moreover, inflammatory cells have been shown to play contradictory roles in the initiation, amplification and resolution of fibrotic disease processes. The central role of the inflammasome molecular platform in contributing to fibrosis is only beginning to be fully appreciated. In this review, we discuss the immune mechanisms that can lead to fibrosis, the inflammasomes that have been implicated in the fibrotic process in the context of the immune response to injury, and also discuss current and emerging therapies that target inflammasome-induced collagen deposition to treat organ fibrosis.

An experimental model of the epithelial to mesenchymal transition and pro-fibrogenesis in urothelial cells related to bladder pain syndrome/interstitial cystitis

Background

Suitable in vitro models are needed to investigate urothelial epithelial to mesenchymal transition (EMT) and pro-fibrogenesis phenotype in bladder pain syndrome/interstitial cystitis (BPS/IC). This study is to establish a novel experimental BPS/IC cell model and explore how different concentrations of tumor necrosis factor (TNF)-α influence the EMT and pro-fibrogenesis phenotype of urothelial cells.

Methods

SV-HUC-1 urothelial cells were cultured with 2, 10, or 50 ng/mL TNF-α to mimic chronic inflammatory stimulation. The EMT and pro-fibrogenesis phenotype, including production of collagen I and pro-fibrosis cytokines, were estimated after 72 h of culture.

Results

The bladder urothelial cells of BPS/IC exhibited upregulated vimentin, TNF-α and TNF receptor, downregulated E-cadherin, and increased collagen I. Higher concentrations of TNF-α (10 and 50 ng/mL) produced an obvious mesenchymal morphology, enhanced invasion and migratory capacity, increased expression of vimentin, and decreased expression of E-cadherin. Collagen I was increased in cells treated with 2 and 10 ng/mL TNF-α after 72 h. Secretion of interleukin (IL)-6 and IL-8 was promoted with 10 and 50 ng/mL TNF-α, while that of IL-1β or transforming growth factor-β was unaffected. Slug and Smad2 were upregulated by TNF-α after 72 h. The Smad pathway was activated most strongly with 10 ng/mL TNF-α and Slug pathway activation was positively correlated with the concentration of TNF-α.

Conclusions

Sustained 10 ng/mL TNF-α stimulation induced the EMT and pro-fibrogenesis phenotype resembling BPS/IC in SV-HUC-1 cells. Minor inflammatory stimulation induced the pro-fibrogenesis phenotype while severe inflammatory stimulation was more likely to produce significant EMT changes. Different degrees of activation of the Slug and Smad pathways may underlie this phenomenon.

Adipose-Derived Mesenchymal Stromal/Stem Cell Line Prevents Hepatic Ischemia/Reperfusion Injury in Rats by Inhibiting Inflammasome Activation

Mesenchymal stromal/stem cells (MSCs) have shown potential in the treatment of degenerative diseases, including ischemia/reperfusion injury (IRI), which occurs during organ transplantation and represents the main cause of post-transplant graft dysfunction. However, MSCs have heterogeneous characteristics, and studies of MSCs therapy have shown a variety of outcomes. To establish a new effective MSCs therapy, we developed an adipose-derived mesenchymal stromal/stem cell line (ASCL) and compared its therapeutic effects on primary adipose-derived MSCs (ASCs) using a hepatocyte co-culture model of hypoxia/reoxygenation in vitro and a rat model of hepatic IRI in vivo. The results showed that both ASCL and ASCs protect against hypoxia by improving hepatocyte viability, inhibiting reactive oxygen species release, and upregulating transforming growth factor-β in vitro. In vivo, ASCL or ASCs were infused into the spleen 24 h before the induction of rat hepatic IRI. The results showed that ASCL significantly improved the survival outcomes compared with the control (normal saline infusion) with the significantly decreased serum levels of liver enzymes and less damage to liver tissues compared with ASCs. Both ASCL and ASCs suppressed NOD-like receptor family pyrin domain-containing 3 inflammasome activation and subsequently reduced the release of activated IL-1β and IL-18, which is considered an important mechanism underlying ASCL and ASCs infusion in hepatic IRI. In addition, ASCL can promote the release of interleukin-1 receptor antagonist, which was previously reported as a key factor in hampering the inflammatory cascade during hepatic IRI. Our results suggest ASCL as a new candidate for hepatic IRI treatment due to its relatively homogeneous characteristics.

Fallopian tubal infertility: the result of Chlamydia trachomatis-induced fallopian tubal fibrosis

Chlamydia trachomatis is one of the most common pathogens of sexually transmitted diseases, and its incidence in genital tract infections is now 4.7% in south China. Infertility is the end result of C. trachomatis-induced fallopian tubal fibrosis and is receiving intense attention from scientists worldwide. To reduce the incidence of infertility, it is important to understand the pathology-related changes of the genital tract where C. trachomatis infection is significant, especially the mechanism of fibrosis formation. During fibrosis development, the fallopian tube becomes sticky and occluded, which will eventually lead to tubal infertility. At present, the mechanism of fallopian tubal fibrosis induced by C. trachomatis infection is unclear. Our study attempted to summarize the possible mechanisms of fibrosis caused by C. trachomatis infection in the fallopian tube by reviewing published studies and further providing potential therapeutic targets to reduce the occurrence of infertility. This study also provides ideas for future research. Factors leading to fallopian tube fibrosis include inflammatory factors, miRNA, ECT, cHSP, and host factors. We hypothesized that C. trachomatis mediates the transcription and translation of EMT and ECM via upregulating TGF signaling pathway, which leads to the formation of fallopian tube fibrosis and ultimately to tubal infertility.

Liver Fibrosis: Therapeutic Targets and Advances in Drug Therapy

Liver fibrosis is an abnormal wound repair response caused by a variety of chronic liver injuries, which is characterized by over-deposition of diffuse extracellular matrix (ECM) and anomalous hyperplasia of connective tissue, and it may further develop into liver cirrhosis, liver failure or liver cancer. To date, chronic liver diseases accompanied with liver fibrosis have caused significant morbidity and mortality in the world with increasing tendency. Although early liver fibrosis has been reported to be reversible, the detailed mechanism of reversing liver fibrosis is still unclear and there is lack of an effective treatment for liver fibrosis. Thus, it is still a top priority for the research and development of anti-fibrosis drugs. In recent years, many strategies have emerged as crucial means to inhibit the occurrence and development of liver fibrosis including anti-inflammation and liver protection, inhibition of hepatic stellate cells (HSCs) activation and proliferation, reduction of ECM overproduction and acceleration of ECM degradation. Moreover, gene therapy has been proved to be a promising anti-fibrosis method. Here, we provide an overview of the relevant targets and drugs under development. We aim to classify and summarize their potential roles in treatment of liver fibrosis, and discuss the challenges and development of anti-fibrosis drugs.

Antifibrotic and anthelminthic effect of casticin on Schistosoma mansoni-infected BALB/c mice

BACKGROUND/PURPOSE

Schistosomiasis is an important tropical disease caused by Schistosoma. Although the pathogenesis of liver fibrosis has been intensively studied, the choice of effective treatment is still inadequate. In this study, we aimed to investigate the potential of using Casticin to treat Schistosoma mansoni-induced liver fibrosis.

METHODS

BALB/c mice were divided into three groups - control, infection, and treatment group. The infection and treatment group were percutaneously infected with 100-120 cercariae. Mice from the treatment group were treated with 20 mg/kg/day Casticin for 14 consecutive days to investigate the potential protective effects of Casticin. Mice were sacrificed and were used for histological, RNA, protein, and parasite burden analysis.

RESULTS

Our results showed that hepatic fibrosis was significantly attenuated, as indicated by histology and reduction of fibrotic markers such as collagen AI, transforming growth factor β (TGF-β), and α-smooth muscle actin (α-SMA). Furthermore, Casticin treatment significantly reduced worm burden. Anthelmintic effect of Casticin was also observed by scanning electron microscopy.

CONCLUSION

Collectively, our study suggested that Casticin may be a beneficial candidate in treating S. mansoni infection.

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.

Neferine Exerts Antioxidant and Anti-Inflammatory Effects on Carbon Tetrachloride-Induced Liver Fibrosis by Inhibiting the MAPK and NF-κB/IκBα Pathways

Reversible liver fibrosis is the consequence of diverse liver injuries. Oxidative stress combined with inflammation is the primary cause of carbon tetrachloride- (CCl₄-) induced liver fibrosis. Neferine is a bibenzyl isoquinoline alkaloid, which has strong anti-inflammatory and antioxidant properties. The present study attempted to find its antiliver fibrosis effect and explore the potential mechanism to relieve oxidative stress and inflammation in rats with CCl₄-induced liver fibrosis. Herein, we found that neferine noticeably mitigated fibrosis and improved liver function. Furthermore, neferine increased the activity of antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and catalase (CAT), but decreased the level of malondialdehyde (MDA). Neferine also decreased the levels of alpha-smooth muscle actin (α-SMA), transforming growth factor β1 (TGF-β1), and inflammatory factors. These results may demonstrate that neferine could effectively inhibit oxidative stress and inflammation in liver fibrosis. To account for the potential mechanism by which neferine relieves oxidative stress and inflammation in liver fibrosis rats, immunohistochemistry analyses and western blotting were performed. The results showed that neferine inhibited the mitogen-activated protein kinase (MAPK) pathway, as evidenced by the reduced phosphorylation of p38 MAPK, ERK 1/2, and JNK. And it inhibited the nuclear factor- (NF-) κB/IκBα pathway, as evidenced by preventing the translocation of NF-κB into nuclei. Our findings indicated a protective role for neferine, acting as an antioxidant and anti-inflammatory agent in CCl₄-induced liver fibrosis.

RNA-Seq analysis of the protection by Dendrobium nobile alkaloids against carbon tetrachloride hepatotoxicity in mice

OBJECTIVE

Dendrobium nobile is a genuine Chinese medicine. Dendrobium nobile Lindl. alkaloids (DNLA) protects against CCl₄-induced acute liver injury. This study used RNA-Seq to explore the mechanisms.

METHODS

Mice were pretreated with DNLA (10 and 20 mg/kg, po) for 7 days, and subsequently intoxicated with CCl₄ (20 μL/kg, ip for 24 h). Liver RNA was extracted and subjected to RNA-Seq. The bioinformatics, including PCA, GO, KEGG, two-dimensional clustering, Ingenuity Pathways Analysis (IPA), and Illumina BaseSpace Correlation Engine (BSCE) were used to analyze the data. qPCR was performed on selected genes to verify RNA-Seq results.

RESULTS

DNLA protection against CCl₄ hepatotoxicity was confirmed by histopathology. PCA revealed the distinct gene expression patterns between the different treatment groups. GO showed that CCl₄ induced the activation, adhesion and proliferation of immune cells. KEGG showed CCl₄ induced oxidative stress, diseases and compromised adaptive responses. CCl₄ induced differentially expressed genes (DEGs) were identified by DESeq2 with Padj < 0.05 and 2D-clustered with other groups. DNLA reverted CCl₄-induced DEGs in a dose-dependent manner. qPCR analysis of S100 g, Sprr1, CCL3/7, Saa2/3, IL1rn, Cox7a2 and Rad15 confirmed RNA-Seq results. IPA showed that CCl₄ treatment altered some signaling and metabolic pathways, which were ameliorated or returned to normal following DNLA treatment. The CCl₄-activated mitochondrial oxidative phosphorylation was illustrated as an example. IPA Upstream Regulator Analysis further revealed the activated or inhibited molecules and chemicals that are responsible for CCl₄-induced DEGs, and DNLA attenuated these changes. BSCE analysis verified that CCl₄-induced DEGs were highly correlated with the GEO database of CCl₄ hepatotoxicity in rodents, and DNLA dose-dependently attenuated such correlation.

CONCLUSION

RNA-Seq revealed CCl₄-induced DEGs, disruption of canonical pathways, activation or inhibition of upstream regulators, which are highly correlated with database for CCl₄ hepatotoxicity. All these changes were attenuated or returned to normal by DNLA, demonstrating the mechanisms for DNLA to protect against CCl₄ hepatotoxicity.

Albumin inhibits the nuclear translocation of Smad3 via interleukin-1beta signaling in hepatic stellate cells

Activation of quiescent hepatic stellate cells (HSCs) to myofibroblasts plays a key role in liver fibrosis. We had previously shown that albumin and its derivative, R-III (a retinol-binding protein—albumin domain III fusion protein), inhibited HSC activation by sequestering retinoic acid (RA) and that R-III administration reduced carbon tetrachloride (CCl₄)-induced liver fibrosis. In this study, we aimed to elucidate the mechanism of action of albumin downstream of RA sequestration. Nuclear factor-κB p65 was evenly distributed in the cytoplasm in activated mouse HSCs, whereas albumin expression or R-III treatment (albumin/R-III) caused the nuclear translocation of p65, probably via RA sequestration, resulting in a dramatic increase in interleukin-1beta (IL-1β) expression. Albumin/R-III in turn induced the phosphorylation of Smad3 at the linker region, inhibiting its nuclear import in an IL-1β-dependent manner. Consistent with the in vitro results, the level of IL-1β mRNA expression was higher in CCl₄/R-III-treated livers than in CCl₄-treated livers. These findings reveal that albumin/R-III inhibits the transforming growth factor-β-Smad3 signaling as well as the retinoic acid receptor-mediated pathway, which probably contributes to the inhibition of HSC activation, and suggest that R-III may be an anti-fibrotic drug candidate.

NLRP3 inflammasome priming and activation in cholestatic liver injury via the sphingosine 1-phosphate/S1P receptor 2/Gα(12/13)/MAPK signaling pathway

NLRP3 inflammasome-driven inflammation represents a key trigger for hepatic fibrogenesis during cholestatic liver injury. However, whether sphingosine 1-phosphate (S1P) plays a role in NLRP3 inflammasome priming and activation remains unknown. Here, we found that the expression of NLRP3 in macrophages and NLRP3 inflammasome activation were significantly elevated in the liver injured by bile duct ligation (BDL). In vitro, S1P promoted the NLRP3 inflammasome priming and activation via S1P receptor 2 (S1PR2) in bone marrow-derived monocyte/macrophages (BMMs). Focusing on BMMs, the gene silencing of Gα12 or Gα13 by specific siRNA suppressed NLRP3 inflammasome priming and pro-inflammatory cytokine (IL-1β and IL-18) secretion, whereas Gα(i/o) and Gαq were not involved in this process. The MAPK signaling pathways (P38, ERK, and JNK) mediated NLRP3 inflammasome priming and IL-1β and IL-18 secretion, whereas blockage of PI3K, ROCK, and Rho family had no such effect. Moreover, JTE-013 (S1PR2 inhibitor) treatment markedly reduced NLRP3 inflammasome priming and activation in BDL-injured liver. Collectively, S1P promotes NLRP3 inflammasome priming and pro-inflammatory cytokines (IL-1β and IL-18) secretion via the S1PR2/Gα(12/13)/MAPK pathway, which may represent an effective therapeutic strategy for liver disease. KEY MESSAGE: • Hepatic NLRP3 expression was significantly elevated in BMMs of BDL-injured mouse liver. • S1P promoted NLRP3 inflammasome priming and activation in BMMs, depending on the S1PR2/Gα(12/13)/MAPK pathway. • Blockade of S1PR2 by JTE-013 reduced NLRP3 inflammasome priming and activation inflammasome in vivo.

Induction of liver fibrosis by CCl4 mediates pathological alterations in the spleen and lymph nodes: The potential therapeutic role of propolis

In an animal models, carbon tetrachloride (CCl4) is a carcinogenic agent that causes liver fibrosis. The current study aims to investigate whether induction in liver-fibrosis by CCl4 in the mouse model could promote the initiation of fibrosis in lymph node and spleen due to sustained increase of inflammatory signals and also aimed to clarify the protective therapeutic effects of propolis. The male mice (BALB/c) were categorized into three experimental sets and each group involved 15 mice. Control group falls into first group; group-II and group-III were injected with CCl4 to induce liver-fibrosis and oral supplementation with propolis was provided in group-III for 4-weeks. A major improvement with hepatic collagen and α-smooth muscle actin (α-SMA) production was aligned with the activation of liver fibrosis from CCl4. Mice treated with CCl4 exhibited collagen deposition towards liver sections, pathological alterations in spleen and lymph node architectures, and a significantly increase the circulation of both T&B cells in secondary lymphoid organs. Mechanically, the secondary lymphoid organs treated with CCl4 in mice exposed a positive growth in α-SMA and collagen expression, increased in proinflammatory cytokine levels and a significant increase in TGF-β, NO and ROS levels. A manifest intensification in the expression of Nrf2, COX-2, and eNOS and upregulation of ASK1 and P38 phosphorylation. Interestingly, addition of propolis-treated CCl4 mice, substantially suppressed deposition of liver collagen, repealed inflammatory signals and resorted CCl4-mediated alterations in signaling cascades, thereby repairing the architectures of the secondary lymphoid organs. Our findings revealed benefits of propolis against fibrotic complications and enhancing secondary lymphoid organ architecture.

HJC0416 Attenuates Fibrogenesis in Activated Hepatic Stellate Cells via STAT3 and NF-κB Pathways

BACKGROUND

Hepatic fibrosis is wound-healing response that is the result of hepatic stellate cell (HSC) activation and subsequent excess extracellular matrix deposition. HSCs can be activated by a variety of inflammatory stimuli as well as through the signal transducer and activator of transcription 3 (STAT3) pathway. HJC0416 is a novel, orally bioavailable small-molecule inhibitor of STAT3 that was developed by our team using a fragment-based drug design approach. Previously, our team has shown that HJC0416 has antifibrogenic effects in activated HSCs. Recently, increasing evidence suggests that nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) plays an important role in the activation of HSCs. In the present study, we examined the role of NF-κB inhibition of HSC activation by HJC0416.

METHODS

LX-2 (human) and HSC-T6 (rat) cell lines were used. Expression levels of extracellular proteins, NF-κB and STAT3 expression and DNA binding, and inflammatory cytokine levels were determined using western blot, ELISA, and immunofluorescence assay.

RESULTS

HJC0416 decreased cell viability in a dose-dependent manner in both cell lines and arrested the cell cycle at the S phase. Increased apoptosis was seen in LX-2 cells through Yo-Pro-1 and propidium iodide immunofluorescent stating. HJC0416 significantly decreased expression of fibronectin and collagen I as well as markedly decreased α-SMA and laminin. HJC0416 inhibited the STAT3 pathway by decreasing phosphorylation of STAT3, as well as signal transduction pathway activation. Notably, HJC0416 also inhibited the classic and alternative pathways of NF-κB activation. HJC0416 inhibited LPS-induced p65 nuclear translocation and DNA binding, as well as prevented phosphorylation and degradation of inhibitory protein IκBα. HJC0416 also prevented phosphorylation of serine residue 536 on p65.

CONCLUSIONS

HJC0416, an inhibitor of STAT3, was found to have antifibrogenic properties in activated hepatic stellate cell lines. In addition, HJC0416 was found to inhibit the NF-κB pathway. Owing to this double effect, HJC0416 demonstrates promise for in vivo experimentation as an antifibrosis treatment.

Creatine Alleviates Doxorubicin-Induced Liver Damage by Inhibiting Liver Fibrosis, Inflammation, Oxidative Stress, and Cellular Senescence

Background: Treatment with the chemotherapy drug doxorubicin (DOX) may lead to toxicities that affect non-cancer cells including the liver. Supplementing the diet with creatine (Cr) has been suggested as a potential intervention to minimize DOX-induced side effects, but its effect in alleviating DOX-induced hepatoxicity is currently unknown. Therefore, we aimed to examine the effects of Cr supplementation on DOX-induced liver damage. Methods: Male Sprague-Dawley rats were fed a diet supplemented with 2% Cr for four weeks, 4% Cr for one week followed by 2% Cr for three more weeks, or control diet for four weeks. Animals then received either a bolus i.p. injection of DOX (15 mg/kg) or saline as a placebo. Animals were then sacrificed five days-post injection and markers of hepatoxicity were analyzed using the liver-to-body weight ratio, aspartate transaminase (AST)-to- alanine aminotransferase (ALT) ratio, alkaline phosphatase (ALP), lipemia, and T-Bilirubin. In addition, hematoxylin and eosin (H&E) staining, Picro-Sirius Red staining, and immunofluorescence staining for CD45, 8-OHdG, and β-galactosidase were performed to evaluate liver morphology, fibrosis, inflammation, oxidative stress, and cellular senescence, respectively. The mRNA levels for biomarkers of liver fibrosis, inflammation, oxidative stress, and senescence-related genes were measured in liver tissues. Chromosomal stability was evaluated using global DNA methylation ELISA. Results: The ALT/AST ratio and liver to body weight ratio tended to increase in the DOX group, and Cr supplementation tended to attenuate this increase. Furthermore, elevated levels of liver fibrosis, inflammation, oxidative stress, and senescence were observed with DOX treatment, and Cr supplementation prior to DOX treatment ameliorated this hepatoxicity. Moreover, DOX treatment resulted in chromosomal instability (i.e., altered DNA methylation profile), and Cr supplementation showed a tendency to restore chromosomal stability with DOX treatment. Conclusion: The data suggest that Cr protected against DOX-induced hepatotoxicity by attenuating fibrosis, inflammation, oxidative stress, and senescence.

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.

Regulation of peroxisome proliferator-activated receptor-gamma activity affects the hepatic stellate cell activation and the progression of NASH via TGF-β1/Smad signaling pathway

Development of liver fibrosis is associated with activation of quiescent hepatic stellate cells (HSCs) into myofibroblasts (activated HSCs), which produce excessive extracellular matrix. Peroxisome proliferator-activated receptor-gamma (PPAR-γ) exerts protective effects on hepatic inflammation and fibrosis. The current study was to explore the function of PPAR-γ on HSC activation and progression of nonalcoholic steatohepatitis (NASH). Our study found that HSCs were gradually activated during the progression of methionine-choline-deficient (MCD) diet-induced NASH, accompanied by decreased PPAR-γ expression and activated TGF-β1/Smad signaling pathway in the liver. PPAR-γ agonist was found to inhibit primary HSCs and NIH/3T3 fibroblast activation and reverted their phenotypical morphology induced by TGF-β1 in vitro. In addition to this, PPAR-γ agonist decreased expression of TGF-β1 and phosphorylation of Smad2/3 while increased expression of Smad7. In vivo, rosiglitazone, a PPAR-γ agonist, inhibited HSC activation and alleviated liver fibrosis and inflammation similarly via inhibiting the activation of TGF-β1/Smad signaling pathway. In parallel, rosiglitazone alleviated hepatic lipid accumulation and peroxidation, beneficial to reverse of NASH. From these findings, it can be concluded that the gradual activation of HSCs is crucial to the progression of NASH and modulating PPAR-γ expression can affect HSC activation via TGF-β1/Smad signaling pathway and thereby influence hepatic fibrogenesis.

Quantitative assessment of portal hypertension with bi-parametric dual-frequency hepatic MR elastography in mouse models

OBJECTIVES

To determine the potential of bi-parametric dual-frequency hepatic MR elastography (MRE) for predicting portal pressure (PP) in mouse models of portal hypertension (PHTN) with the presence of varying hepatic fibrosis.

METHODS

We studied 73 wild-type male mice, including 22 mice with hepatic congestion, 20 mice with cholestatic liver injury, and 31 age-matched sham mice. Hepatic shear stiffness (SS) and volumetric strain (VS) were calculated by 3D MRE acquired at 80 and 200 Hz. We measured PP immediately after MRE. Liver fibrosis was verified by hydroxyproline assay. We predicted PP by fitting generalized linear models with single- and dual-frequency SS and VS, respectively. The relationship between predicted and actual PP was evaluated by Spearman's correlation. We compared the prediction accuracy of portal hypertension for all models with DeLong tests at a significance level of 0.05.

RESULTS

Animals with congestive or cholestatic liver disease developed significant PHTN and hepatic fibrosis to varying degrees. In both models, SS increased, while VS decreased significantly compared with shams. All bi-parametric models had high diagnostic accuracy for PHTN. The dual-frequency models (AUCs: 0.90 [81-95%], 0.91 [81-95%]) had substantially or significantly higher accuracy than single-frequency ones (AUCs: 0.83 [71-91%], and 0.78 [66-87%]). The predicted PP of dual-frequency models also showed stronger correlations with actual PP than single-frequency predictions.

CONCLUSIONS

The bi-parametric dual-frequency model improved the diagnostic accuracy of liver MRE in diagnosing PHTN in preclinical models. This technical advance has the potential to monitor PHTN progression and treatment efficacy in the presence of varying fibrosis.

KEY POINTS

• Bi-parametric hepatic MR elastography can predict portal pressure. • The prediction models of shear stiffness and volumetric strain with dual-frequency measurements demonstrate high diagnostic accuracy (AUCs > 0.9) in two different portal hypertension mouse models with varying fibrosis.

Phosphodiesterases in the Liver as Potential Therapeutic Targets of Cirrhotic Portal Hypertension

Liver cirrhosis is a frequent condition with high impact on patients' life expectancy and health care systems. Cirrhotic portal hypertension (PH) gradually develops with deteriorating liver function and can lead to life-threatening complications. Other than an increase in intrahepatic flow resistance due to morphological remodeling of the organ, a functional dysregulation of the sinusoids, the smallest functional units of liver vasculature, plays a pivotal role. Vascular tone is primarily regulated by the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway, wherein soluble guanylate cyclase (sGC) and phosphodiesterase-5 (PDE-5) are key enzymes. Recent data showed characteristic alterations in the expression of these regulatory enzymes or metabolite levels in liver cirrhosis. Additionally, a disturbed zonation of the components of this pathway along the sinusoids was detected. This review describes current knowledge of the pathophysiology of PH with focus on the enzymes regulating cGMP availability, i.e., sGC and PDE-5. The results have primarily been obtained in animal models of liver cirrhosis. However, clinical and histochemical data suggest that the new biochemical model we propose can be applied to human liver cirrhosis. The role of PDE-5 as potential target for medical therapy of PH is discussed.

Role of NLRP3 inflammasome in liver disease

Inflammasomes have become an important natural sensor of host immunity, and can protect various organs against pathogenic infections, metabolic syndromes, cellular stress and cancer metastasis. Inflammasomes are intracellular multi-protein complexes found in both parenchymal and non-parenchymal cells, stimulating the initiation of caspase-1 and interleukin (IL)-1β and IL-18 in response to cell danger signals. Inflammasomes induce cell death mechanisms. The potential role of NOD-like receptor protein 3 (NLRP3) inflammasome in alcoholic and non-alcoholic steatohepatitis, hepatitis, nanoparticle-induced liver injury and other liver diseases has recently attracted widespread attention from clinicians and researchers. In this review we summarize the role played by the NLRP3 inflammasome in molecular and pathophysiological mechanisms in the pathogenesis and progression of liver disease. This article aims to establish that targeting the NLRP3 inflammasome and other inflammasome components may make a significant therapeutic approach to the treatment of liver disease.

Hepatic microenvironment underlies fibrosis in chronic hepatitis B patients

BACKGROUND

Chronic hepatitis B virus (HBV) infection is a leading cause of liver morbidity and mortality worldwide. Liver fibrosis resulting from viral infection-associated inflammation and direct liver damage plays an important role in disease management and prognostication. The mechanisms underlying the contribution of the liver microenvironment to fibrosis in HBV patients are not fully understood. There is an absence of effective clinical treatments for liver fibrosis progression; thus, establishing a suitable in vitro microenvironment in order to design novel therapeutics and identify molecular biomarkers to stratify patients is urgently required.

AIM

To examine a subset of pre-selected microenvironment factors of chronic HBV patients that may underlie fibrosis, with a focus on fibroblast activation.

METHODS

We examined the gene expression of key microenvironment factors in liver samples from patients with more advanced fibrosis compared with those with less severe fibrosis. We also used the human stellate cell line LX-2 in the in vitro study. Using different recombinant cytokines and growth factors or their combination, we studied how these factors interacted with LX-2 cells and pinpointed the cross-talk between the aforementioned factors and screened the most important factors.

RESULTS

Of the secreted factors examined, transforming growth factor (TGF)-β1, interleukin (IL)-1β and tumor necrosis factor (TNF)-α were increased in patients with advanced fibrosis. We found that besides TGF-β1, IL-1β can also induce a profibrotic cascade by stimulating the expression of connective tissue growth factor and platelet-derived growth factor (PDGF) in LX-2 cells. Furthermore, the proinflammatory response can be elicited in LX-2 cells following treatment with IL-1β and TNF-α, suggesting that stellate cells can respond to proinflammatory stimuli. By combining IL-1β and TGF-β1, we observed not only fibroblast activation as shown by αlpha-smooth muscle actin and PDGF induction, but also the inflammatory response as shown by increased expression of IL-1β.

CONCLUSION

Collectively, our data from HBV patients and in vitro studies demonstrate that the hepatic microenvironment plays an important role in mediating the crosstalk between profibrotic and proinflammatory responses and modulating fibrosis in chronic HBV patients. For the establishment of a suitable in vitro microenvironment for HBV-induced liver fibrosis, not only TGF-β1 but also IL-1β should be considered as a necessary environmental factor.

A Chinese case series of Schnitzler syndrome and complete remission in one tocilizumab-treated patient

Schnitzler syndrome (SchS) is a rare acquired systemic autoinflammatory disease. The major clinical features of SchS are urticarial rash and monoclonal gammopathy, accompanied by fever, joint pain, and lymphadenopathy. There were few reports about SchS in Chinese population. Herein, we describe two patients with SchS in China and conducted a systematic literature review about SchS. Two Chinese Han patients were diagnosed as SchS in our department from 2017 to 2019. Their phenotype and genotype were carefully documented and studied. We also conducted a systematic literature review about SchS. There was one man (66 years old) and one woman (49 years old). Recurrent fever and urticarial rash occurred in both of them during the febrile attacks and normalized in asymptomatic intervals. Other manifestations included arthralgia, lymphadenopathy, and hearing loss. Hepatic cirrhosis and epilepsy were seen in the male patient. None of them had bone pain or family histories. Serum monoclonal IgM gammopathy was found in both patients. MyD88 gene mutation L258P was identified in the female patient. They were treated with tocilizumab and tripterygium wilfordii Hook F (TwHF) respectively, and both showed good response. The rarity and diversity of SchS make it difficult to be recognized. Anti-IL-6 agents may be alternative therapies when anti-IL-1 therapy is unresponsive or unavailable. Due to the case report, the effect of TwHF in the treatment of SchS should be further studied.

Role of pyroptosis in liver diseases

Pyroptosis is known as a novel form of pro-inflammatory cell death program, which is exceptional from other types of cell death programs. Particularly, pyroptosis is characterized by Gasdermin family-mediated pore formation and subsequently cellular lysis, also release of several pro-inflammatory intracellular cytokines. In terms of mechanism, there are two signaling pathways involved in pyroptosis, including caspase-1, and caspase-4/5/11 mediated pathways. However, pyroptosis plays important roles in immune defense mechanisms. Recent studies have demonstrated that pyroptosis plays significant roles in the development of liver diseases. In our review, we have focused on the role of pyroptosis based on the molecular and pathophysiological mechanisms in the development of liver diseases. We have also highlighted targeting of pyroptosis for the therapeutic implications in liver diseases in the near future.

Characterization of a Novel Interleukin-1 Receptor Antagonist from Sheep (Ovis aries)

Interleukin-1 receptor antagonist (IL-1Ra) is an antagonist of IL-1β binding IL-1β receptors but does not induce intracellular responses or signal transduction. In this study, the full-length complementary DNA (cDNA) of the IL-1Ra gene (OaIL-1Ra) was identified from sheep (Ovis aries) using rapid amplification of cDNA ends PCR and submitted to GenBank with the accession number KC425613. The OaIL-1Ra cDNA comprised an open reading frame of 525 bp encoding a protein of 19765.8 Da, a 5'-untranslated region (UTR) of 27 bp, and a 3'-UTR of 676 bp with a poly(A) tail. Recombinant OaIL-1Ra with bioactivity was expressed in a prokaryotic expression system, and a monoclonal antibody against native OaIL-1Ra was prepared. Through Western blot analyses, the OaIL-1Ra protein was widely expressed in lung, heart, spleen, liver, kidney, muscle, intestine, lymphonodi, rumen, and white blood cells, with the highest levels in liver and spleen. The expression of OaIL-1Ra in primary cultured white blood cells of sheep were highly induced in a time-dependent manner when challenged with different bacteria. These results implied that OaIL-1Ra is associated with immune responses during bacterial infections.

Inflammation: Cause or consequence of chronic cholestatic liver injury

Cholestasis is a result of obstruction of the biliary tracts. It is a common cause of liver pathology after exposure to toxic xenobiotics and during numerous other liver diseases. Accumulation of bile acids in the liver is thought to be a major driver of liver injury during cholestasis and can lead to eventual liver fibrosis and cirrhosis. As such, current therapy in the field of chronic liver diseases with prominent cholestasis relies heavily on increasing choleresis to limit accumulation of bile acids. Many of these same diseases also present with autoimmunity before the onset of cholestasis though, indicating the inflammation may be an initiating component of the pathology. Moreover, cytotoxic inflammatory mediators accumulate during cholestasis and can propagate liver injury. Anti-inflammatory biologics and small molecules have largely failed clinical trials in these diseases though and as such, targeting inflammation as a means to address cholestatic liver injury remains debatable. The purpose of this review is to understand the different roles that inflammation can play during cholestatic liver injury and attempt to define how new therapeutic targets that limit or control inflammation may be beneficial for patients with chronic cholestatic liver disease.

Macrophage Function in the Pathogenesis of Non-alcoholic Fatty Liver Disease: The Mac Attack

Obesity is a prevalent predisposing factor to non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease in the developed world. NAFLD spectrum of disease involves progression from steatosis (NAFL), to steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC). Despite clinical and public health significance, current FDA approved therapies for NAFLD are lacking in part due to insufficient understanding of pathogenic mechanisms driving disease progression. The etiology of NAFLD is multifactorial. The induction of both systemic and tissue inflammation consequential of skewed immune cell metabolic state, polarization, tissue recruitment, and activation are central to NAFLD progression. Here, we review the current understanding of the above stated cellular and molecular processes that govern macrophage contribution to NAFLD pathogenesis and how adipose tissue and liver crosstalk modulates macrophage function. Notably, the manipulation of such events may lead to the development of new therapies for NAFLD.

Crosstalk network among multiple inflammatory mediators in liver fibrosis

Liver fibrosis is the common pathological basis of all chronic liver diseases, and is the necessary stage for the progression of chronic liver disease to cirrhosis. As one of pathogenic factors, inflammation plays a predominant role in liver fibrosis via communication and interaction between inflammatory cells, cytokines, and the related signaling pathways. Damaged hepatocytes induce an increase in pro-inflammatory factors, thereby inducing the development of inflammation. In addition, it has been reported that inflammatory response related signaling pathway is the main signal transduction pathway for the development of liver fibrosis. The crosstalk regulatory network leads to hepatic stellate cell activation and proinflammatory cytokine production, which in turn initiate the fibrotic response. Compared with the past, the research on the pathogenesis of liver fibrosis has been greatly developed. However, the liver fibrosis mechanism is complex and many pathways involved need to be further studied. This review mainly focuses on the crosstalk regulatory network among inflammatory cells, cytokines, and the related signaling pathways in the pathogenesis of chronic inflammatory liver diseases. Moreover, we also summarize the recent studies on the mechanisms underlying liver fibrosis and clinical efforts on the targeted therapies against the fibrotic response.