Activation of inflammation is an important mechanism in the development of nonalcoholic steatohepatitis (NASH). This study aims to delineate how mitophagy affects NLRP3 inflammasome activation in ...hepatic lipotoxicity. Mice were fed a high fat/calorie diet (HFCD) for 24 weeks. Primary rat hepatocytes were treated with palmitic acid (PA) for various periods of time. Mitophagy was measured by protein levels of LC3II and P62. NLRP3, caspase-1, interleukin (IL)-18, and IL-1β at mRNA and protein levels were used as indicators of inflammasome activation. Along with steatotic progression in HFCD-fed mice, ratio of LC3II/β-actin was decreased concurrently with increased levels of liver P62, NLRP3, caspase-1, IL-1β, IL-18, and serum IL-1β levels in late-stage NASH. PA treatment resulted in mitochondrial oxidative stress and initiated mitophagy in primary hepatocytes. The addition of cyclosporine A did not change LC3II/Τοmm20 ratios; but P62 levels were increased after an extended duration of PA exposure, indicating a defect in autophagic activity. Along with impaired mitophagy, mRNA and protein levels of NLRP3, caspase-1, IL-18 and IL-1β were upregulated by PA treatment. Pretreatment with MCC950, N-acetyl cysteine or acetyl-l-carnitine reversed inflammasome activation and a pyroptotic cascade. Additionally, mitophagic flux was partially recovered as indicated by increases in LC3II/Tomm20 ratio, parkin, and PINK1 expression, and decreased P62 expression. The findings suggest that impaired mitophagy triggers hepatic NLRP3 inflammasome activation in a murine NASH model and primary hepatocytes. The new insights into inflammasome activation through mitophagy advance our understanding of how fatty acids elicit lipotoxicity through oxidant stress and autophagy in mitochondria.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Nonalcoholic steatohepatitis-associated hepatocellular carcinoma (NASH-HCC) is a malignancy whose incidents are rapidly increasing. However, the mechanisms that drive development of HCC in a ...steatotic microenvironment remain unknown. Here we report that the obesity-associated protein JCAD is expressed at significantly higher levels in human NASH-HCC specimens compared with pericarcinoma specimens. High JCAD expression was verified in multiple hepatoma cell lines. Forced overexpression of JCAD in hepatoma cells promoted tumor growth and proliferation, whereas JCAD silencing yielded opposite effects. JCAD interacted with the kinase domain of the tumor suppressor kinase LATS2, a core component of the Hippo signaling pathway. JCAD overexpression inhibited the ability of LATS2 to phosphorylate YAP in this pathway, in turn upregulating CCND1 and GLI2 to promote hepatoma cell proliferation. JCAD was induced by fatty acid overload in hepatic cells and was highly expressed in a mouse model of NASH-precarcinoma lesions, where the ratio of phospho-YAP to YAP was decreased. In human NASH-HCC specimens, JCAD expression and YAP phosphorylation patterns paralleled with the mouse model. Our findings illuminate a new role for JCAD and its critical interplay in the Hippo signaling cascade during the transition of NASH to HCC, with potential implications for therapeutic development in this setting.
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Background and aims
Treatment of non‐alcoholic steatohepatitis (NASH) is challenging, because suppressing fibrotic progression has not been achieved consistently by drug candidates currently in ...clinical trials. The aim of this study was to investigate the molecular interplays underlying NASH‐associated fibrosis in a mouse NASH model and human specimens.
Methods
Mice were divided into 4 groups: Controls; NASH (high fat/Calorie diet plus high fructose and glucose in drinking water, HFCD‐HF/G) for 16 weeks; HFCD‐HF/G plus docosahexaenoic acid (DHA) for 16 or 8 weeks.
Results
Along with NASH progression, fibrotic deposition was documented in HFCD‐HF/G‐fed mice. Liver succinate content was significantly increased along with decreased expression of succinate dehydrogenase‐A (SDH‐A) in these mice; whereas, GPR‐91 receptor expression was much enhanced in histology compared to control mice, and co‐localized histologically with hepatic stellate cells (HSCs). Succinate content was increased in fatty acid‐overloaded primary hepatocytes with significant oxidant stress and lipotoxicity. Exposure to succinate led to up‐regulation of GPR‐91 receptor in primary and immortalized HSCs. In contrast, suppression of GPR‐91 receptor expression abolished succinate stimulatory role in GPR‐91 expression and extracellular matrix production in HSCs. All these changes were minimized or abrogated by DHA supplementation in vivo or in vitro. Moreover, GPR‐91 receptor expression correlates with severity of fibrosis in human NASH biopsy specimens.
Conclusion
Succinate accumulation in steatotoic hepatocytes may result in HSC activation through GPR‐91 receptor signalling in NASH progression, and the cross‐talk between hepatocytes and HSC through GPR‐91 signalling is most likely to be the molecular basis of fibrogenesis in NASH.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Nonalcoholic steatohepatitis (NASH) is a progressive form of nonalcoholic fatty liver disease (NAFLD), characterized with hepatocellular steatosis, ballooning, lobular inflammation, fibrotic ...progression, and insulin resistance. NASH may progress to cirrhosis and hepatocellular carcinoma (HCC), which are the major indications for liver transplantation and the causes for mortality. Thus far, there are no approved pharmacotherapeutics for the treatment of NASH. Given the complexity of NASH pathogenesis at multifaceted aspects, such as lipotoxicity, inflammation, insulin resistance, mitochondrial dysfunction and fibrotic progression, pharmacotherapeutics under investigation target different key pathogenic pathways to gain either the resolution of steatohepatitis or regression of fibrosis, ideally both. Varieties of pharmacologic candidates have been tested in clinical trials and have generated some positive results. On the other hand, recent failure or termination of a few phase II and III trials is disappointing in this field. In face to growing challenges in pharmaceutical development, this review intends to summarize the latest data of new medications which have completed phase II or III trials, and discuss the rationale and preliminary results of several combinatory options. It is anticipated that with improved understanding of NASH pathogenesis and critical endpoints, efficient pharmacotherapeutics will be available for the treatment of NASH with an acceptable safety profile.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Recent investigations of gut microbiota have contributed to understanding of the critical role of microbial community in pathophysiology. Dysbiosis not only causes disturbance directly to the ...gastrointestinal tract but also affects the liver through gut‐liver axis. Various types of dysbiosis have been documented in alcoholic liver disease (ALD), nonalcoholic fatty liver disease, autoimmune hepatitis (AIH), primary sclerosing cholangitis, and may be crucial for the initiation, progression, or deterioration to end‐stage liver disease. A few microbial species have been identified as the causal factors leading to these chronic illnesses that either do not have clear etiologies or lack effective treatment. Notably, cytolysin‐producing Enterococcus faecalis, Klebsiella pneumoniae and Enterococcus gallinarum were defined for ALD, NASH, and AIH, respectively. These groundbreaking discoveries drive a rapid development in innovative therapeutics, such as fecal microbial transplantation and implementation of specific bacteriophages in addition to prebiotics, probiotics, or synbiotics for intervention of dysbiosis. Although most emerging interventions are in preclinical development or early clinical trials, a better delineation of specific dysbiosis in these disorders at metabolic, immunogenic, or molecular levels in establishing particular causal effects aids in modulating or correcting the microbial community which is the part of daily life for human being.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Abstract
Background
Since interferon regulatory factor (IRF) family functions in immune response to viral infection, its role in colorectal cancer (CRC) has not been inspected before. This study ...tries to investigate members of IRF family using bioinformatics approaches in aspect of differential expressions, biological function, tumor immune infiltration and clinical prognostic value for patients with CRC.
Methods
Transcriptome profiles data, somatic mutations and clinical information of CRC were obtained from COAD/READ dataset of The Cancer Genome Atlas (TCGA) as a training set. Gene expression data (GSE17536 and GSE39582) were downloaded from the Gene Expression Omnibus as a validating set. A random forest algorithm was used to score the risk for every case. Analyzing gene and function enrichment, constructing protein–protein interaction and noncoding RNA network, identifying hub-gene, characterizing tumor immune infiltration, evaluating differences in tumor mutational burden (TMB) and sensitivity to chemotherapeutics or immunotherapy were performed by a series of online tools and R packages. Immunohistochemical (IHC) examinations were carried out validation in tissue samples.
Results
Principal-component analysis (PCA) suggested that the transcript expression levels of nine members of IRF family differed between normal colorectum and CRC. The risk score constructed by IRF family not only acted as an independent factor for predicting survival in CRC patients with different biological processes, signaling pathways and TMB, but also indicated different immunotherapy response with diverse immune and stromal cells infiltration. IRF3 and IRF7 were upregulated in CRC and suggested a shorter survival time in patients with CRC. Differentially expressed members of IRF family exhibited varying degrees of immune cell infiltration. IHC analysis showed a positive association between IRF3 and IRF7 expression and tumor-infiltrating immune cells, including CD4
+
T cell and CD68
+
macrophages.
Conclusions
On account of differential expression, IRF family members can help to predict both response to immunotherapy and clinical prognosis of patients with CRC. Our bioinformatic investigation not only gives a preliminary picture of the genetic features as well as tumor microenvironment, but it may provide a clue for further experimental exploration and verification on IRF family members in CRC.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
Background
Tumor-associated macrophages (TAM) are immunosuppressive cells that contribute to impaired anti-cancer immunity. Iron plays a critical role in regulating macrophage function. ...However, it is still elusive whether it can drive the functional polarization of macrophages in the context of cancer and how tumor cells affect the iron-handing properties of TAM. In this study, using hepatocellular carcinoma (HCC) as a study model, we aimed to explore the effect and mechanism of reduced ferrous iron in TAM.
Methods
TAM from HCC patients and mouse HCC tissues were collected to analyze the level of ferrous iron. Quantitative real-time PCR was used to assess M1 or M2 signature genes of macrophages treated with iron chelators. A co-culture system was established to explore the iron competition between macrophages and HCC cells. Flow cytometry analysis was performed to determine the holo-transferrin uptake of macrophages. HCC samples from The Cancer Genome Atlas (TCGA) were enrolled to evaluate the prognostic value of transferrin receptor (TFRC) and its relevance to tumor-infiltrating M2 macrophages.
Results
We revealed that ferrous iron in M2-like TAM is lower than that in M1-like TAM. In vitro analysis showed that loss of iron-induced immunosuppressive M2 polarization of mouse macrophages. Further experiments showed that TFRC, the primary receptor for transferrin-mediated iron uptake, was overexpressed on HCC cells but not TAM. Mechanistically, HCC cells competed with macrophages for iron to upregulate the expression of M2-related genes via induction of HIF-1α, thus contributing to M2-like TAM polarization. We further clarified the oncogenic role of TFRC in HCC patients by TCGA. TFRC is significantly increased in varieties of malignancies, including HCC, and HCC patients with high TFRC levels have considerably shortened overall survival. Also, TFRC is shown to be positively related to tumor-infiltrating M2 macrophages.
Conclusions
Collectively, we identified iron starvation through TFRC-mediated iron competition drives functional immunosuppressive polarization of TAM, providing new insight into the interconnection between iron metabolism and tumor immunity.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Interferon regulatory factor 2 (IRF-2) acts as an anti-oncogene in gastric cancer (GC); however, the underlying mechanism remains unknown.
This study determined the expression of IRF-2 in GC tissues ...and adjacent non-tumor tissues using immunohistochemistry (IHC) and explored the predictive value of IRF-2 for the prognoses of GC patients. Cell function and xenograft tumor growth experiments in nude mice were performed to test tumor proliferation ability, both in vitro and in vivo. Chromatin immunoprecipitation sequencing (ChIP-Seq) assay was used to verify the direct target of IRF-2.
We found that IRF-2 expression was downregulated in GC tissues and was negatively correlated with the prognoses of GC patients. IRF-2 negatively affected GC cell proliferation both in vitro and in vivo. ChIP-Seq assay showed that IRF-2 could directly activate AMER-1 transcription and regulate the Wnt/β-catenin signaling pathway, which was validated using IHC, in both tissue microarray and xenografted tumor tissues, western blot analysis, and cell function experiments.
Increased expression of IRF-2 can inhibit tumor growth and affect the prognoses of patients by directly regulating AMER-1 transcription in GC and inhibiting the Wnt/β-catenin signaling pathway.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Summary
Addition of peginterferon alpha (PEG‐IFN add‐on) to entecavir (ETV) treatment after a short lead‐in phase results in more response than ETV monotherapy in HBeAg‐positive chronic hepatitis B ...infection (CHB). This study is the first to assess long‐term efficacy of this treatment strategy. Patients who received ETV ± 24 weeks of PEG‐IFN add‐on in a global trial (ARES study) and completed follow‐up were eligible to participate in this observational LTFU study if they had at least one combined HBeAg and HBV DNA measurement beyond week 96 of the ARES study. The primary endpoint was combined response (HBeAg loss and HBV DNA <200 IU/mL) at LTFU. In total, 48 patients treated with PEG‐IFN add‐on and 48 patients treated with ETV monotherapy were included. The median follow‐up duration was 226 (IQR 51) weeks, and 86/96 (90%) patients were initial non‐responders. At LTFU, combined response was present in 13 (27%) vs 11 (23%) patients (P = 0.81), and 1 log10 HBsAg decline in 59% vs 28% (P = 0.02) for PEG‐IFN add‐on and ETV monotherapy, respectively. In 41 initial non‐responders who continued ETV therapy, combined response at LTFU was present in 9 patients (PEG‐IFN add‐on: 5/22 23%; ETV monotherapy: 4/19 21%). Beyond week 96 of follow‐up, rates of serological response became comparable between PEG‐IFN add‐on and ETV monotherapy. Although in this LTFU study initial non‐responders were overrepresented in the add‐on arm, PEG‐IFN add‐on possibly leads rather to accelerated HBeAg loss than to increased long‐term HBeAg loss rates.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
microRNAs (miRNAs) and miRNA-mediated regulatory networks are promising candidates in the prevention and treatment of cancer, but the role of specific miRNAs involved in hepatocellular carcinoma ...(HCC) remains to be elusive. Herein, we found that miR-106b-5p is upregulated in both HCC patients’ tumor tissues and HCC cell lines. The miR-106b-5p expression level was positively correlated with α-fetoprotein (AFP), hepatitis B surface antigen (HBsAg), and tumor size. Overexpression of miR-106b-5p promoted cell proliferation, migration, cell cycle G1/S transition, and tumor growth, while decreased miR-106b-5p expression had opposite effects. Mechanistic studies showed that B-cell translocation gene 3 (BTG3), a known antiproliferative protein, was a direct target of miR-106b-5p, whose expression level is inversely correlated with miR-106b-5p expression. Moreover, miR-106b-5p positively regulates cell proliferation in a BTG3-dependent manner, resulting in upregulation of Bcl-xL, cyclin E1, and CDK2, as well as downregulation of p27. More importantly, we also demonstrated that miR-106b-5p enhances the resistance to sorafenib treatment in a BTG3-dependent manner. The in vivo findings showed that mice treated with a miR-106b-5p sponge presented a smaller tumor burden than controls, while the mice injected cells treated with miR-106b-5p had more considerable tumor burden than controls. Altogether, these data suggest that miR-106b-5p promotes cell proliferation and cell cycle and increases HCC cells’ resistance to sorafenib through the BTG3/Bcl-xL/p27 signaling pathway.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
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