Impaired interferon signaling in chronic hepatitis C patients with advanced fibrosis via the transforming growth factor beta signaling pathway

Expression of interferon-stimulated genes, but not polymorphisms in the interferon α/β receptor 2 gene, is associated with coronavirus disease 2019 mortality

Excessive inflammatory response is a hallmark of severe COVID-19. This study investigated the associations between interferon-stimulated genes (ISGs) expression, genetic variation in the interferon α/β receptor 2 (IFNAR2) gene, and COVID-19 mortality. We investigated 67 patients with moderate-to-severe COVID-19. Of them, 22 patients (32.8 %) died because of COVID-19. We examined the expression of ISGs in total RNA of peripheral whole blood. We observed a significant increase in the expression of all ISGs examined in non-surviving patients, indicating a heightened interferon type I signaling activation in non-survived patients. Subsequently, we analyzed whether the increase in ISGs expression was correlated with polymorphism within the IFNAR2 gene. Intriguingly, no significant association was observed between IFNAR2 gene polymorphism and COVID-19 mortality. Similarly, no association was noted between the IFNAR2 and ISGs expression levels. Overall, our data showed that higher ISGs expression, which presumably indicates heightened interferon type I activation, is associated with COVID-19 mortality.

Mechanism of myocardial fibrosis regulation by IGF-1R in atrial fibrillation through the PI3K/Akt/FoxO3a pathway

Atrial structural remodeling takes on a critical significance to the occurrence and maintenance of atrial fibrillation (AF). As revealed by recent data, insulin-like growth factor-1 receptor (IGF-1R) plays a certain role in tissue fibrosis. In this study, the mechanism of IGF-1R in atrial structural remodeling was examined based on in vivo and in vitro experiments. First, cluster analysis of AF hub genes was conducted, and then the molecular mechanism was proposed by which IGF-1R regulates myocardial fibrosis via the PI3K/Akt/FoxO3a pathway. Subsequently, the mentioned mechanism was verified in human cardiac fibroblasts (HCFs) and rats transduced with IGF-1 overexpression type 9 adeno-associated viruses. The results indicated that IGF-1R activation up-regulated collagen Ⅰ protein expression and Akt phosphorylation in HCFs and rat atrium. The administration of LY294002 reversed the above phenomenon, improved the shortening of atrial effective refractory period, and reduced the increased incidence of AF and atrial fibrosis in rats. The transfection of FoxO3a siRNA reduced the anti-fibrotic effect of LY294002 in HCFs. The above data revealed that activation of IGF-1R takes on a vital significance to atrial structural remodeling by facilitating myocardial fibrosis and expediting the occurrence and maintenance of AF through the regulation of the PI3K/Akt/FoxO3a signaling pathway.

Comparative study between effects of ginkgo biloba extract and extract loaded on gold nanoparticles on hepatotoxicity induced by potassium bromate

In human organs, potassium bromate (KBrO3) produces toxicity. The main causes of KBrO3 hepatotoxicity are the formation of reactive oxygen species (ROS) and DNA damage. The purpose of this study is to show how ginkgo biloba extract (GBE) and extract loaded with nanogold particles (GBE@AuNPs) affect hepatotoxicity caused by KBrO3. The rats were separated into eight groups: control (group I), GBE (group II), AuNPs (group III), GBE@AuNPs (group IV), KBrO3 (group V), KBrO3 and GBE (group VI), KBrO3 and AuNPS (group VII), and KBrO3 and GBE@AuNPs (group VIII). KBrO3 generated DNA damage spots in a comet assay, which were associated with increased inflammatory indicators (IL-6), decreased anti-apoptotic Bcl-2, and increased apoptotic markers (Bax and caspase-3). The inflammatory, apoptotic, and ultrastructural alterations in liver tissue produced by KBrO3 were reduced in treated groups VI, VII, or VIII. The hepatotoxic effects of KBrO3 were reduced when GBE, AuNPs, or GBE@AuNPs were used; the particular GBE@AuNPs were the most effective.

PLOD3 contributes to HER-2 therapy resistance in gastric cancer through FoxO3/Survivin pathway

Human epidermal growth factor receptor 2 (HER-2), a famous therapeutic target for breast cancer, is also associated with an increased risk of recurrence and poor outcomes of other malignancies, including gastric cancer. Yet the mechanism of HER-2 therapy resistance remains controversial due to the heterogeneity of gastric adenocarcinoma. We know, Procollagen-Lysine,2-Oxoglutarate 5-Dioxygenase 3 (PLOD3), a key gene coding enzymes that catalyze the lysyl hydroxylation of extracellular matrix collagen, plays an important contributor to HER-2 targeting agent Trastuzumab resistance in gastric cancer. Herein, we analyzed clinical samples of gastric cancer patients and gastric cancer cell lines and identified PLOD3, unveiled that depletion of PLOD3 leads to decreased cell proliferation, tumor growth and Trastuzumab sensitivity in these Trastuzumab resistant GC cell lines. Clinically, increased PLOD3 expression correlates with decreased Trastuzumab therapy responsiveness in GC patients. Mechanistically, we show that PLOD3 represses tumor suppressor FoxO3 expression, therefore upregulating Survivin protein expression that contributes to Trastuzumab resistance in GC. Therefore, our study identifies a new signaling axis PLOD3-FoxO3- Survivin pathway that may be therapeutically targeted in HER-2 positive gastric cancer.

FoxO3 restricts liver regeneration by suppressing the proliferation of hepatocytes

Upon injury, the liver is capable of substantial regeneration from the original tissue until an appropriate functional size. The underlying mechanisms controlling the liver regeneration processes are not well elucidated. Previous studies have proposed that the transcription factor FoxO3 is involved in various liver diseases, but its exact role in the regulation of liver regeneration remains largely unclear. To directly test the detailed role of FoxO3 in liver regeneration, both a constitutive Albumin-Cre driver line and adeno-associated virus serotype 8 (AAV8)-Tbg-Cre (AAV-Cre)-injected adult FoxO3^fl/fl mice were subjected to 70% partial hepatectomy (PH). Our data demonstrate that FoxO3 deletion accelerates liver regeneration primarily by limiting polyploidization and promoting the proliferation of hepatocytes during liver regeneration. RNA-seq analysis indicates that FoxO3 deficiency greatly alters the expression of gene sets associated with cell proliferation and apoptosis during liver regeneration. Chromatin immunoprecipitation-PCR (ChIP-PCR) and luciferase reporter assays reveal that FoxO3 promotes the expression of Nox4 but suppresses the expression of Nr4a1 in hepatocytes. AAV8 virus-mediated overexpression of Nox4 and knockdown of Nr4a1 significantly suppressed hepatocyte proliferation and liver regeneration in FoxO3-deficient mice. We demonstrate that FoxO3 negatively controls hepatocyte proliferation through Nox4 upregulation and Nr4a1 downregulation, thereby ensuring appropriate functional regeneration of the liver. Our findings provide novel mechanistic insight into the therapeutic mechanisms of FoxO3 in liver damage and repair.

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.

Induced regulatory T cells suppress Tc1 cells through TGF-β signaling to ameliorate STZ-induced type 1 diabetes mellitus

Type 1 diabetes mellitus (T1D) is a chronic autoimmune condition in which the immune system destroys insulin-producing pancreatic β cells. In addition to well-established pathogenic effector T cells, regulatory T cells (Tregs) have also been shown to be defective in T1D. Thus, an increasing number of therapeutic approaches are being developed to target Tregs. However, the role and mechanisms of TGF-β-induced Tregs (iTregs) in T1D remain poorly understood. Here, using a streptozotocin (STZ)-induced preclinical T1D mouse model, we found that iTregs could ameliorate the development of T1D and preserve β cell function. The preventive effect was associated with the inhibition of type 1 cytotoxic T (Tc1) cell function and rebalancing the Treg/Tc1 cell ratio in recipients. Furthermore, we showed that the underlying mechanisms were due to the TGF-β-mediated combinatorial actions of mTOR and TCF1. In addition to the preventive role, the therapeutic effects of iTregs on the established STZ-T1D and nonobese diabetic (NOD) mouse models were tested, which revealed improved β cell function. Our findings therefore provide key new insights into the basic mechanisms involved in the therapeutic role of iTregs in T1D.

TGF-β2 silencing to target biliary-derived liver diseases

OBJECTIVE

TGF-β2 (TGF-β, transforming growth factor beta), the less-investigated sibling of TGF-β1, is deregulated in rodent and human liver diseases. Former data from bile duct ligated and MDR2 knockout (KO) mouse models for human cholestatic liver disease suggested an involvement of TGF-β2 in biliary-derived liver diseases.

DESIGN

As we also found upregulated TGFB2 in liver tissue of patients with primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC), we now fathomed the positive prospects of targeting TGF-β2 in early stage biliary liver disease using the MDR2-KO mice. Specifically, the influence of TgfB2 silencing on the fibrotic and inflammatory niche was analysed on molecular, cellular and tissue levels.

RESULTS

TgfB2-induced expression of fibrotic genes in cholangiocytes and hepatic stellate cellswas detected. TgfB2 expression in MDR2-KO mice was blunted using TgfB2-directed antisense oligonucleotides (AON). Upon AON treatment, reduced collagen deposition, hydroxyproline content and αSMA expression as well as induced PparG expression reflected a significant reduction of fibrogenesis without adverse effects on healthy livers. Expression analyses of fibrotic and inflammatory genes revealed AON-specific regulatory effects on Ccl3, Ccl4, Ccl5, Mki67 and Notch3 expression. Further, AON treatment of MDR2-KO mice increased tissue infiltration by F4/80-positive cells including eosinophils, whereas the number of CD45-positive inflammatory cells decreased. In line, TGFB2 and CD45 expression correlated positively in PSC/PBC patients and localised in similar areas of the diseased liver tissue.

CONCLUSIONS

Taken together, our data suggest a new mechanistic explanation for amelioration of fibrogenesis by TGF-β2 silencing and provide a direct rationale for TGF-β2-directed drug development.

Upregulation of the Long Non-Coding RNA HULC by Hepatitis C Virus and its Regulation of Viral Replication

Background

Many long noncoding RNAs (lncRNAs) have important roles in biological processes. The lncRNA HULC was found to be upregulated in human hepatoma tissues. HULC is thought to be involved in multiple steps of hepatoma development and progression; however, the relationship between HULC and hepatitis C virus (HCV) infection, which is a leading cause of hepatoma, remains unclear.

Methods

We examined the effect of HCV replication on HULC expression and the underlying mechanism using cell culture systems. Subsequently, we tested the effect of HULC suppression and overexpression on HCV replication. Finally, we examined the impact of HCV eradication on HULC expression using human liver tissue and blood samples.

Results

HCV replication increased HULC expression in cell cultures. A promoter assay showed that an HCV nonstructural protein, NS5A, increased HULC transcription. HULC suppression inhibited HCV replication; conversely, its overexpression enhanced HCV replication. These effects on HCV replication seemed to occur by the modification of HCV translation. Measurements from human liver and blood samples showed that HCV eradication significantly reduced HULC levels in the liver and blood.

Conclusions

HCV infection increases HULC expression in vitro and in vivo. HULC modulates HCV replication through an HCV internal ribosome entry site–directed translation step.

CircMRPS35 suppresses gastric cancer progression via recruiting KAT7 to govern histone modification

Background

Aberrant expression of circular RNAs contributes to the initiation and progression of cancers, but the underlying mechanism remains elusive.

Methods

RNA-seq and qRT-PCR were performed to screen differential expressed circRNAs between gastric cancer tissues and adjacent normal tissues. Candidate circRNA (circMRPS35) was screened out and validated by qRT-PCR. Cell proliferation and invasion ability were determined by CCK-8 and cell invasion assays. RNA-seq, GO-pathway, RNA pull-down and ChIRP were further applied to search for detailed mechanism.

Results

Here, a novel circRNA named circMRPS35, was screened out by RNA-seq in gastric cancer tissues, whose expression is related to clinicopathological characteristics and prognosis in gastric cancer patients. Biologically, circMRPS35 suppresses the proliferation and invasion of gastric cancer cells in vitro and in vivo. Mechanistically, circMRPS35 acts as a modular scaffold to recruit histone acetyltransferase KAT7 to the promoters of FOXO1 and FOXO3a genes, which elicits acetylation of H4K5 in their promoters. Particularly, circMRPS35 specifically binds to FOXO1/3a promoter regions directly. Thus, it dramatically activates the transcription of FOXO1/3a and triggers subsequent response of their downstream target genes expression, including p21, p27, Twist1 and E-cadherin, resulting in the inhibition of cell proliferation and invasion. Moreover, circMRPS35 expression positively correlates with that of FOXO1/3a in gastric cancer tissues.

Conclusions

Our findings not only reveal the pivotal roles of circMRPS35 in governing histone modification in anticancer treatment, but also advocate for triggering circMRPS35/KAT7/FOXO1/3a pathway to combat gastric cancer.

Role of FoxO3a as a negative regulator of the cardiac myofibroblast conversion induced by TGF-β1

Cardiac fibroblasts (CFs) are necessary to maintain extracellular matrix (ECM) homeostasis in the heart. Normally, CFs are quiescent and secrete small amounts of ECM components, whereas, in pathological conditions, they differentiate into more active cells called cardiac myofibroblasts (CMF). CMF conversion is characteristic of cardiac fibrotic diseases, such as heart failure and diabetic cardiomyopathy. TGF-β1 is a key protein involved in CMF conversion. SMADs are nuclear factor proteins activated by TGF-β1 that need other proteins, such as forkhead box type O (FoxO) family members, to promote CMF conversion. FoxO1, a member of this family protein, is necessary for TGF-β1-induced CMF conversion, whereas the role of FoxO3a, another FoxO family member, is unknown. FoxO3a plays an important role in many fibrotic processes in the kidney and lung. However, the participation of FoxO3a in the conversion of CFs into CMF is not clear. In this paper, we demonstrate that TGF-β1 decreases the activation and expression of FoxO3a in CFs. FoxO3a regulation by TGF-β1 requires activated SMAD3, ERK1/2 and Akt. Furthermore, we show that FoxO1 is crucial in the FoxO3a regulation induced by TGF-β1, as shown by overexpressed FoxO1 enhancing and silenced FoxO1 suppressing the effects of TGF-β1 on FoxO3a. Finally, the regulation of TGF-β1-induced CMF conversion was enhanced by FoxO3a silencing and suppressed by inhibited FoxO3a degradation. Considering these collective findings, we suggest that FoxO3a acts as a negative regulator of the CMF conversion that is induced by TGF-β1.

Interferon Lambda and Liver Fibrosis

Fibrosis is a highly conserved and coordinated wound healing response to injury. In the liver, injury is promoted by immune effector mechanisms that are common across various disease etiologies and even between organs such as lungs, kidneys, heart, and other organs. Thus, the liver represents a useful model to study inflammation and repair, particularly as it is frequently biopsied in clinical contexts. Currently, strong evidence implicates IFNL3/4 polymorphisms and interferon (IFN)-λ3 levels as determinants of the extent of hepatic inflammation and fibrosis in viral and nonviral liver diseases, as well as in governing the severity of nonhepatotropic viral diseases. Interestingly, IFNL3/4 polymorphisms and IFN-λ3 levels correlate with fibrosis extent in other organs such as the lung and kidney. In this review, we discuss the association between IFN-λ and tissue inflammation and fibrosis in human disease and the potential clinical utility of the findings.

MicroRNA-10a Impairs Liver Metabolism in Hepatitis C Virus-Related Cirrhosis Through Deregulation of the Circadian Clock Gene Brain and Muscle Aryl Hydrocarbon Receptor Nuclear Translocator-Like 1

The circadian rhythm of the liver plays an important role in maintaining its metabolic homeostasis. We performed comprehensive expression analysis of microRNAs (miRNAs) using TaqMan polymerase chain reaction of liver biopsy tissues to identify the miRNAs that are significantly up‐regulated in advanced chronic hepatitis C (CHC). We found miR‐10a regulated various liver metabolism genes and was markedly up‐regulated by hepatitis C virus infection and poor nutritional conditions. The expression of miR‐10a was rhythmic and down‐regulated the expression of the circadian rhythm gene brain and muscle aryl hydrocarbon receptor nuclear translocator‐like 1 (Bmal1) by directly suppressing the expression of RA receptor‐related orphan receptor alpha (RORA). Overexpression of miR‐10a in hepatocytes blunted circadian rhythm of Bmal1 and inhibited the expression of lipid synthesis genes (sterol regulatory element binding protein [SREBP]1, fatty acid synthase [FASN], and SREBP2), gluconeogenesis (peroxisome proliferator‐activated receptor gamma coactivator 1 alpha [PGC1α]), protein synthesis (mammalian target of rapamycin [mTOR] and ribosomal protein S6 kinase [S6K]) and bile acid synthesis (liver receptor homolog 1 [LRH1]). The expression of Bmal1 was significantly correlated with the expression of mitochondrial biogenesis‐related genes and reduced Bmal1 was associated with increased serum alanine aminotransferase levels and progression of liver fibrosis in CHC. Thus, impaired circadian rhythm expression of Bmal1 by miR‐10a disturbs metabolic adaptations, leading to liver damage, and is closely associated with the exacerbation of abnormal liver metabolism in patients with advanced CHC. In patients with hepatitis C‐related liver cirrhosis, liver tissue miR‐10a levels were significantly associated with hepatic reserve, fibrosis markers, esophageal varix complications, and hepatitis C‐related hepatocellular carcinoma recurrence. Conclusion: MiRNA‐10a is involved in abnormal liver metabolism in cirrhotic liver through down‐regulation of the expression of the circadian rhythm gene Bmal1. Therefore, miR‐10a is a possible useful biomarker for estimating the prognosis of liver cirrhosis.

Targeting metabolic dysregulation for fibrosis therapy

Fibrosis is the abnormal deposition of extracellular matrix, which can lead to organ dysfunction, morbidity, and death. The disease burden caused by fibrosis is substantial, and there are currently no therapies that can prevent or reverse fibrosis. Metabolic alterations are increasingly recognized as an important pathogenic process that underlies fibrosis across many organ types. As a result, metabolically targeted therapies could become important strategies for fibrosis reduction. Indeed, some of the pathways targeted by antifibrotic drugs in development - such as the activation of transforming growth factor-β and the deposition of extracellular matrix - have metabolic implications. This Review summarizes the evidence to date and describes novel opportunities for the discovery and development of drugs for metabolic reprogramming, their associated challenges, and their utility in reducing fibrosis. Fibrotic therapies are potentially relevant to numerous common diseases such as cirrhosis, non-alcoholic steatohepatitis, chronic renal disease, heart failure, diabetes, idiopathic pulmonary fibrosis, and scleroderma.

CD56- CD16+ NK cells from HIV-infected individuals negatively regulate IFN-γ production by autologous CD8+ T cells

The percentage of human CD56^- CD16⁺ NK cells increases during chronic infection with human HIV; however, the biologic role of CD56^- CD16⁺ NK cells in HIV infection is unclear. Our results demonstrate that the percentage of CD56^- CD16⁺ NK cells producing IL-10 and TGF-β was higher than CD56^dim CD16⁺ NK cells. CD56^- CD16⁺ NK cells could inhibit IFN-γ production by autologous CD8⁺ T cells, and this inhibition could be partially reversed by anti-IL-10, anti-TGF-β, or anti-PD-L1 mAbs. CD56^- CD16⁺ NK cells are potential targets for the development of novel immune therapies against HIV infection.

Electric Stimulation Hyperthermia Relieves Inflammation via the Suppressor of Cytokine Signaling 3-Toll Like Receptor 4 Pathway in a Prostatitis Rat Model

Purpose

Chronic prostatitis (CP), including chronic pelvic pain syndrome (CPPS), is the most commonly encountered manifestation of prostatitis. The aim of this study was to evaluate the effect of electric stimulation hyperthermia treatment (ESHT) on CP/CPPS and to explore the underlying mechanism.

Materials and Methods

RWPE-2 cells with lipopolysaccharide-induced inflammation and a prostatitis rat model induced by 17β-estradiol and dihydrotestosterone underwent sham, electric stimulation, or ESHT treatment. Four weeks later, cells, supernatants, and rat prostates were collected for analysis using immunohistochemistry, Western blots, and enzyme-linked immunosorbent assays.

Results

We found that ESHT improved prostatitis in vivo and attenuated inflammation in vitro. ESHT significantly induced suppressor of cytokine signaling 3 (SOCS3) expression and subsequently promoted HSP70. It attenuated inflammation through decreased expression of toll-like receptor 4 (TLR4), nuclear factor kappa B, and subsequent inflammatory cytokines. ESHT also inhibited apoptosis and released growth factor in tissue affected by prostatitis.

Conclusions

ESHT improved CP/CPPS and reversed pathologic changes of prostatitis by inhibiting the SOCS3-TLR4 pathway.

Histological and biochemical evaluation of transforming growth factor-β activation and its clinical significance in patients with chronic liver disease

Transforming growth factor-β (TGF-β) is a key driver for liver fibrogenesis. TGF-β must be activated in order to function. Plasma kallikrein (PLK) is a TGF-β activator that cleaves the latency-associated protein (LAP) between arginine⁵⁸ and lysine⁵⁹ residues and releases active TGF-β from the latent TGF-β-LAP complex. Thus, the generation of two LAP degradation products, ending at arginine⁵⁸ (R⁵⁸/LAP-DPs) and beginning from lysine⁵⁹ (L⁵⁹/LAP-DPs), reflects PLK-dependent TGF-β activation. However, the significance and details of TGF-β activation in patients with chronic liver disease (CLD) remain uncertain. We herein examined the PLK-dependent TGF-β activation in patients by detecting R⁵⁸ and L⁵⁹/LAP-DPs. A total of 234 patients with CLD were included in this study. Liver biopsy specimens were used for immunostaining to detect R⁵⁸/LAP-DPs, while plasma samples were subjected to an enzyme-linked immunosorbent assay to measure the L⁵⁹/LAP-DP concentration. R⁵⁸/LAP-DP was robustly expressed in and around the sinusoidal cells before the development of the fibrous regions. The R⁵⁸/LAP-DP expression at fibrosis stage 1 was higher than at any other stages, and the relationship between the plasma L⁵⁹/LAP-DP level and the stage of fibrosis also showed a similar trend. The abundance of plasma L⁵⁹/LAP-DP showed no correlation with the levels of direct serum biomarkers of liver fibrosis; however, its changes during interferon-based therapy for chronic hepatitis C were significantly associated with virological responses. Our results suggest that PLK-dependent TGF-β activation occurs in the early stages of fibrosis and that its unique surrogate markers, R⁵⁸ and L⁵⁹/LAP-DPs, are useful for monitoring the clinical course of CLD.

The osteopontin-CD44 axis in hepatic cancer stem cells regulates IFN signaling and HCV replication

Osteopontin (OPN) is involved in cell proliferation, migration, inflammation, and tumor progression in various tissues. OPN induces stemness by interacting with CD44, but the functional relevance of OPN-mediated interferon (IFN) signaling and hepatitis C virus (HCV) replication in stem cell populations remains unclear. In this study, we investigated the effect of OPN on HCV replication and IFN signaling in cancer stem cells (CSCs) positive for epithelial cell adhesion molecule (EpCAM) and CD44. We show that the EpCAM⁺/CD44⁺ CSCs show marked HCV replication when compared to EpCAM⁻/CD44⁻ cells. In addition, OPN significantly enhances this HCV replication in EpCAM⁺/CD44⁺ CSCs and markedly suppresses IFN-stimulated gene expression. The GSK-3β inhibitor BIO increases the EpCAM⁺/CD44⁺ CSC population and OPN expression and impairs IFN signaling via STAT1 degradation. Taken together, our data suggest that OPN enhances HCV replication in the EpCAM⁺/CD44⁺ CSCs, while it also negatively regulates the IFN signaling pathway via inhibition of STAT1 phosphorylation and degradation. Therefore, OPN may represent a novel therapeutic target for treating HCV-related hepatocellular carcinoma.

Downregulation of Glt25d1 aggravates carbon tetrachloride‑induced acute hepatic injury through activation of the TGF‑β1/Smad2 signaling pathway

Collagen β (1-O) galactosyltransferase 1 (GLT25D1) has been reported to transfer galactose to hydroxylysine residues via β (1-O) linkages in collagen. The present study investigated the function of the collagen galactosyltransferase activity of GLT25D1 against carbon tetrachloride (CCl₄)-induced acute liver injury in vitro. Glt25d1^+/− mice and wild-type (WT) mice were injected intraperitoneally with the same dose of CCl₄. The grade of hepatic injury and the extent of hepatocyte necrosis in the acute phase were assessed 48 h following CCl₄ injection. Hepatocyte necrosis was evaluated by histological examination and by serum alanine aminotransferase and aspartate aminotransferase levels, which were higher in the Glt25d1^+/− mice compared with those in the WT mice. Reverse transcription-quantitative polymerase chain reaction was performed, and the results demonstrated that the mRNA expression levels of inflammatory cytokines, including tumor necrosis factor-α and interleukin-6 were significantly increased in the Glt25d1^+/− mice. Furthermore, western blot analyses were performed, and the results demonstrated that the protein levels of cleaved caspase-3 and −9 were also markedly increased in the Glt25d1^+/− liver, indicating that hepatocyte apoptosis was induced. Additionally, the expression levels of transforming growth factor (TGF)-β1 and phosphorylated small mothers against decapentaplegic (Smad)2 were markedly upregulated, indicating activation of the TGF-β1/Smad2 signaling pathway during CCl₄-induced acute liver injury in Glt25d1^+/− mice. CCl₄ administration also resulted in severe damage to Glt25d1^+/− primary hepatocytes in vitro. Taken together, the downregulation of Glt25d1 deteriorated CCl₄-induced liver injury in mice, which may involve triggering inflammatory responses, apoptosis and TGF-β1/Smad2 signaling pathway activation.

Extrahepatic Upregulation of Transforming Growth Factor Beta 2 in HCV Genotype 4-Induced Liver Fibrosis

Elevated levels of transforming growth factor-β (TGF-β) family mediate myofibroblast generation and extracellular matrix deposition, thus making TGF-β recognized as major profibrogenic cytokines. In this article, we provide evidence that extrahepatic TGF-β2 expression at RNA and protein levels in peripheral leucocytes and serum, respectively, correlate with hepatic fibrogenesis. Current study includes a total of 110 subjects [89 naive hepatitis C virus (HCV)-infected patients (f0-f4) and 21 healthy controls]. Array profiling of 84 fibrosis-related transcripts revealed that TGF-β2 RNA was significantly upregulated compared with controls. Transcription results were confirmed by specific qRT-PCR on TGF-β2 RNA in peripheral leucocytes and TGF-β2 protein by ELISA in serum. PCR array and qRT-PCR for TGF-β2 RNA in peripheral leucocytes revealed that HCV-infected patients, regardless of the degree of fibrosis, had significantly elevated TGF-β2 RNA levels compared with controls (P = 0.018 and 0.047, respectively). This extrahepatic upregulation of TGF-β2 RNA was confirmed by elevated levels of secretory TGF-β2 protein in infected sera (P = 0.001). The Area Under the Curve of the receiver operating characteristic curve for the TGF-β2 protein between patients and controls was 0.80, a value that renders serum TGF-β2 protein a promising biomarker for liver fibrosis.

Regulation of interferon signaling and HCV‑RNA replication by extracellular matrix

Although interferon (IFN)‑based treatment of patients with chronic hepatitis C virus (HCV) infection is widely applied, treatment resistance is often observed in patients with advanced liver fibrosis. Given that the molecular mechanisms of IFN resistance in liver fibrosis remain elusive, the present study investigated the effects of extracellular matrix (ECM) on IFN signaling in hepatic cells. The native HuH‑7 human hepatoma cell line and HuH‑7 cells were stably transfected with full‑length HCV‑RNA fused with Renilla luciferase (OR6 cells) were cultured on ECM‑coated dishes or non‑coated plastic dishes (NDs), and treated with human IFN‑α. In Huh‑7 cells cultured on coated dishes, the IFN‑stimulated response element (ISRE) luciferase activity was measured following ISRE plasmid transfection and the expression of IFN‑stimulated genes (ISG) were significantly lower than those in cells cultured on NDs. In addition, after IFN‑α treatment, the amount of HCV‑RNA and viral protein produced by OR6 cells cultured on coated dishes was higher than that produced by cells cultured on NDs. When cells were treated with β1‑integrin‑blocking antibody to disrupt the cell‑matrix interaction, the ISRE luciferase activity was restored, and the protein expression of ISG was increased, while that of HCV proteins was suppressed. Treatment of cells with integrin‑linked kinase (ILK) inhibitor or focal adhesion kinase (FAK) inhibitor restored the ISRE luciferase activity and expression of ISG proteins. These results suggested that β1‑integrin‑mediated signals affected the IFN signaling and promoted HCV replication. Therefore, the accumulation of ECM in liver fibrosis may impair IFN signaling through β1‑integrin‑mediated signaling involving ILK and FAK.

FOXO1/3: Potential suppressors of fibrosis

Fibrosis is a universally age-related disease that involves nearly all organs. It is typically initiated by organic injury and eventually results in organ failure. There are still few effective therapeutic strategy targets for fibrogenesis. Forkhead box proteins O1 and O3 (FOXO1/3) have been shown to have favorable inhibitory effects on fibroblast activation and subsequent extracellular matrix production and can ameliorate fibrosis levels in numerous organs, including the heart, liver, lung, and kidney; they are therefore promising targets for anti-fibrosis therapy. Moreover, we can develop appropriate strategies to make the best use of FOXO1/3's anti-fibrosis properties. The information reviewed here should be significant for understanding the roles of FOXO1/3 in fibrosis and should contribute to the design of further studies related to FOXO1/3 and the fibrotic response and shed light on a potential treatment for fibrosis.

Hepatitis B virus X protein induces hepatic stem cell-like features in hepatocellular carcinoma by activating KDM5B

AIM

To determine the role of hepatitis B virus X protein (HBx), HBx in regulating hepatic progenitor cell (HPC)-like features in hepatocellular carcinoma (HCC) and the underlying molecular mechanisms.

METHODS

We used a retrovirus vector to introduce wild type HBx or empty vector into HepG2 cells. We then used these cells to analyze cell proliferation, senescence, transformation, and stem-like features. Gene expression profiling was carried out on Affymetrix GeneChip Human U133A2.0 ver.2 arrays according to the manufacturer’s protocol. Unsupervised hierarchical clustering analysis and Class Comparison analysis were performed by BRB-Array Tools software Version 4.2.2. A total of 238 hepatitis B virus (HBV)-related HCC patients’ array data were used for analyzing clinical features.

RESULTS

The histone demethylase KDM5B was significantly highly expressed in HBV-related HCC cases (P < 0.01). In HBV proteins, only HBx up-regulated KDM5B by activating c-myc. Hepatic stem cell (HpSC) markers (EpCAM, AFP, PROM1, and NANOG) were significantly highly expressed in KDM5B-high HCC cases (P < 0.01). KDM5B played an important role in maintaining HpSC-like features and was associated with a poor prognosis. Moreover, inhibition of KDM5B suppressed spheroid formation and cell invasion in vitro.

CONCLUSION

HBx activates the histone demethylase KDM5B and induces HPC-like features in HCC. Histone demethylases KDM5B may be an important therapeutic target against HBV-related HCC cases.

Systematic Identification and Bioinformatic Analysis of MicroRNAs in Response to Infections of Coxsackievirus A16 and Enterovirus 71

Hand, foot, and mouth disease (HFMD), mainly caused by coxsackievirus A16 (CVA16) and enterovirus 71 (EV71) infections, remains a serious public health issue with thousands of newly diagnostic cases each year since 2008 in China. The mechanisms underlying viral infection, however, are elusive to date. In the present study, we systematically investigated the host cellular microRNA (miRNA) expression patterns in response to CVA16 and EV71 infections. Through microarray examination, 27 miRNAs (15 upregulated and 12 downregulated) were found to be coassociated with the replication process of two viruses, while the expression levels of 15 and 5 miRNAs were significantly changed in CVA16- and EV71-infected cells, respectively. A great number of target genes of 27 common differentially expressed miRNAs were predicted by combined use of two computational target prediction algorithms, TargetScan and MiRanda. Comprehensive bioinformatic analysis of target genes in GO categories and KEGG pathways indicated the involvement of diverse biological functions and signaling pathways during viral infection. These results provide an overview of the roles of miRNAs in virus-host interaction, which will contribute to further understanding of HFMD pathological mechanisms.

The significance of low levels of LINC RP1130-1 expression in human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common neoplasms. Little progress has been made in the diagnosis and treatment of HCC and its prognosis remains poor. Studies have increasingly found that long non-coding RNA (lncRNA) is involved in the regulation of the occurrence and development of HCC. To investigate the diagnostic and prognostic value of lncRNA in HCC, the current study examined 25 lncRNAs with differing levels of expression (according to the fold change) in microarray databases. Expression of LINC RP1130-1 was found to be markedly down-regulated in 51 HCC tissues compared to matching adjacent non-tumor liver tissues. The pattern of expression and clinical significance of LINC RP1130-1 were examined in HCC. The area under the receiver operating characteristic (ROC) curve was 0.74 for LINC RP1130-1. The expression of LINC RP1130-1 was associated with clinical stage, the number of tumors, portal vein tumor thrombus (PVTT), and microvascular invasion (MVI). More importantly, patients with a low level of LINC RP1130-1 expression had a shorter recurrence-free survival (RFS) (n = 51, p < 0.05) than those with a high level of LINC RP1130-1 expression. Taken together, these findings indicate that a low level of LINC RP1130-1 expression in patients with HCC may be a powerful tumor biomarker, with potential clinical use in diagnosing and predicting the prognosis for patients with HCC.

Splenectomy enhances the therapeutic effect of adipose tissue-derived mesenchymal stem cell infusion on cirrhosis rats

BACKGROUND & AIMS

Clinical studies suggest that splenectomy improves liver function in cirrhotic patients, but the influence of splenectomy on stem cell transplantation is poorly understood. This study investigated the effect of splenectomy on stem cell infusion and elucidated its mechanism.

METHODS

Rat adipose tissue-derived mesenchymal stem cells were infused into cirrhosis rats with or without splenectomy, followed by the assessment of the in vivo distribution of stem cells and pathological changes. Stromal cell-derived factor-1 and hepatocyte growth factor expression were also investigated in splenectomized cirrhosis patients and rats.

RESULTS

Splenectomy, prior to cell infusion, improved liver function and suppressed fibrosis progression more efficiently than cell infusion alone in the experimental cirrhosis model. Stromal cell-derived factor-1 and hepatocyte growth factor levels after splenectomy were increased in patients and rats. These upregulated cytokines significantly facilitated stem cell motility, migration and proliferation in vitro. C-X-C chemokine receptor type 4 neutralization weakened the promotion of cell migration by these cytokines. The infused cells integrated into liver fibrosis septa and participated in regeneration more efficiently in splenectomized rats. Direct coculture with stem cells led to inhibition of hepatic stellate cell proliferation. In addition, hepatocyte growth factor induced hepatic stellate cell apoptosis via the c-jun N-terminal kinase-p53 pathway.

CONCLUSIONS

Splenectomy prior to cell infusion enhanced the therapeutic effect of stem cells on cirrhosis, which involved upregulation of stromal cell-derived factor-1 and hepatocyte growth factor after splenectomy.

TGF-β1 and TGF-β2 abundance in liver diseases of mice and men

TGF-β1 is a major player in chronic liver diseases promoting fibrogenesis and tumorigenesis through various mechanisms. The expression and function of TGF-β2 have not been investigated thoroughly in liver disease to date. In this paper, we provide evidence that TGF-β2 expression correlates with fibrogenesis and liver cancer development.Using quantitative realtime PCR and ELISA, we show that TGF-β2 mRNA expression and secretion increased in murine HSCs and hepatocytes over time in culture and were found in the human-derived HSC cell line LX-2. TGF-β2 stimulation of the LX-2 cells led to upregulation of the TGF-β receptors 1, 2, and 3, whereas TGF-β1 treatment did not alter or decrease their expression. In liver regeneration and fibrosis upon CCl4 challenge, the transient increase of TGF-β2 expression was accompanied by TGF-β1 and collagen expression. In bile duct ligation-induced fibrosis, TGF-β2 upregulation correlated with fibrotic markers and was more prominent than TGF-β1 expression. Accordingly, MDR2-KO mice showed significant TGF-β2 upregulation within 3 to 15 months but minor TGF-β1 expression changes. In 5 of 8 hepatocellular carcinoma (HCC)/hepatoblastoma cell lines, relatively high TGF-β2 expression and secretion were observed, with some cell lines even secreting more TGF-β2 than TGF-β1. TGF-β2 was also upregulated in tumors of TGFα/cMyc and DEN-treated mice. The analysis of publically available microarray data of 13 human HCC collectives revealed considerable upregulation of TGF-β2 as compared to normal liver.Our study demonstrates upregulation of TGF-β2 in liver disease and suggests TGF-β2 as a promising therapeutic target for tackling fibrosis and HCC.

Hepatitis C Virus-Induced Monocyte Differentiation Into Polarized M2 Macrophages Promotes Stellate Cell Activation via TGF-β

BACKGROUND & AIMS

Monocyte and macrophage (MΦ) activation contributes to the pathogenesis of chronic hepatitis C virus (HCV) infection. Disease pathogenesis is regulated by both liver-resident MΦs and monocytes recruited as precursors of MΦs into the damaged liver. Monocytes differentiate into M1 (classic/proinflammatory) or M2 (alternative/anti-inflammatory) polarized MΦs in response to tissue microenvironment. We hypothesized that HCV-infected hepatoma cells (infected with Japanese fulminant hepatitis-1 [Huh7.5/JFH-1]) induce monocyte differentiation into polarized MΦs.

METHODS

Healthy human monocytes were co-cultured with Huh7.5/JFH-1 cells or cell-free virus for 7 days and analyzed for MΦ markers and cytokine levels. A similar analysis was performed on circulating monocytes and liver MΦs from HCV-infected patients and controls.

RESULTS

Huh7.5/JFH-1 cells induced monocytes to differentiate into MΦs with increased expression of CD14 and CD68. HCV-MΦs showed M2 surface markers (CD206, CD163, and Dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN)) and produced both proinflammatory and anti-inflammatory cytokines. HCV-induced early interleukin 1β production promoted transforming growth factor (TGF)β production and MΦ polarization to an M2 phenotype. TGF-β secreted by M2-MΦ led to hepatic stellate cell activation indicated by increased expression of collagen, tissue inhibitor of metalloproteinase 1, and α-smooth muscle actin. In vivo, we observed a significant increase in M2 marker (CD206) expression on circulating monocytes and in the liver of chronic HCV-infected patients. Furthermore, we observed the presence of a unique collagen-expressing CD14⁺CD206⁺ monocyte population in HCV patients that correlated with liver fibrosis.

CONCLUSIONS

We show an important role for HCV in induction of monocyte differentiation into MΦs with a mixed M1/M2 cytokine profile and M2 surface phenotype that promote stellate cell activation via TGF-β. We also identified circulating monocytes expressing M2 marker and collagen in chronic HCV infection that can be explored as a biomarker.

Ginkgo biloba extract mitigates liver fibrosis and apoptosis by regulating p38 MAPK, NF-κB/IκBα, and Bcl-2/Bax signaling

Background

Liver fibrosis is the consequence of diverse liver injuries and can eventually develop into liver cirrhosis. Ginkgo biloba extract (GBE) is an extract from dried ginkgo leaves that has many pharmacological effects because of its various ingredients and has been shown to be hepatoprotective.

Purpose and methods

Aimed to investigate the underlying protective mechanisms of GBE on carbon tetrachloride (CCl₄)-induced liver fibrosis in rats. Male Sprague Dawley rats were randomly divided into four groups: control group (C), model group (M), low-dose group (L), and high-dose group (H). Liver fibrosis was induced by CCl₄ groups M, L, and H: group C was administered saline. In addition, GBE at different doses was used to treat groups L and H.

Results

The results of hematoxylin and eosin staining, Masson’s trichrome staining, a liver function index, and a liver fibrosis index showed that GBE application noticeably mitigated fibrosis and improved the function of the liver. The western blotting and immunohistochemistry analyses indicated that GBE reduced liver fibrosis not only by inhibiting p38 MAPK and NF-κBp65 via inhibition of IκBα degradation but also by inhibiting hepatocyte apoptosis via downregulation of Bax, upregulation of Bcl-2, and subsequent inhibition of caspase-3 activation. Inflammation-associated factors and hepatic stellate cell (HSC)-activation markers further demonstrated that GBE could effectively inhibit HSC activation and inflammation as a result of its regulation of p38 MAPK and nuclear factor-kappa B/IκBα signaling.

Conclusion

Our findings indicated a novel role for GBE in the treatment of liver fibrosis. The potential mechanisms may be associated with the following signaling pathways: 1) the p38 MAPK and nuclear factor-kappa B/IκBα signaling pathways (inhibiting inflammation and HSCs activation) and 2) the Bcl-2/Bax signaling pathway (inhibiting the apoptosis of hepatocytes).

Mechanisms of Virologic Failure with Direct-Acting Antivirals in Hepatitis C and Strategies for Retreatment

The current standard of care for hepatitis C therapy is the combination of direct-acting antiviral (DAA) agents. These orally administered medications target the viral proteins and halt the hepatitis C virus lifecycle. Despite high cure rates with these novel drugs, virologic failure with DAAs are of mounting concern as real-world sustained virologic response 12 rates seem lower than expected. The mechanisms of virologic failure to DAAs are likely multifactorial, including baseline resistance variants, the efficacy of the agents used, and host factors. Salvage therapy for DAA virologic failures is an area of emerging research.

Sorting out cirrhosis: mechanisms of non-response to hepatitis C therapy

Although cirrhosis has long been recognized as an important negative predictor of treatment response for hepatitis C virus (HCV) therapy, the mechanisms underlying this association remain relatively poorly understood. Treatment has progressed rapidly with the introduction of highly effective all-oral therapies, with promising outcomes even in patients with advanced cirrhosis. However, even with the new therapies, it is clear that patients with cirrhosis require special attention. Efficacy continues to be somewhat reduced compared to non-cirrhotic patients and safety is an important concern. In this review, we explore the reasons for treatment non-response in patients with cirrhosis. We focus on how cirrhosis impacts on four important areas including drug delivery, drug uptake and metabolism, immune responses and drug toxicity with examples from the clinical and basic literature. Fortunately, as treatment continues to progress, many of the challenges of treating patients with cirrhosis will become less and less problematic.

Activins and Follistatin in Chronic Hepatitis C and Its Treatment with Pegylated-Interferon-α Based Therapy

Pegylated-interferon-α based therapy for the treatment of chronic hepatitis C (CHC) is considered suboptimal as not all patients respond to the treatment and it is associated with several side effects that could lead to dose reduction and/or termination of therapy. The currently used markers to monitor the response to treatment are based on viral kinetics and their performance in the prediction of treatment outcome is moderate and does not combine accuracy and their values have several limitations. Hence, the development of new sensitive and specific predictor markers could provide a useful tool for the clinicians and healthcare providers, especially in the new era of interferon-free therapy, for the classification of patients according to their response to the standard therapy and only subscribing the novel directly acting antiviral drugs to those who are anticipated not to respond to the conventional therapy and/or have absolute contraindications for its use. The importance of activins and follistatin in the regulation of immune system, liver biology, and pathology has recently emerged. This review appraises the up-to-date knowledge regarding the role of activins and follistatin in liver biology and immune system and their role in the pathophysiology of CHC.