Expression profile analysis of the inflammatory response regulated by hepatocyte nuclear factor 4α. BMC Genomics. 2011;12:128. [PMID: 21352552 PMCID: PMC3053261 DOI: 10.1186/1471-2164-12-128]

Royal jelly fatty acids downregulate ANGPTL8 expression through the decrease in HNF4α protein in human hepatoma HepG2 cells

Royal jelly (RJ) intake has been reported to be effective for reducing serum lipids; however, the mechanism is not fully understood. Angiopoietin-like protein 8 (ANGPTL8), a secreted protein, plays a key role in lipid metabolism. In this study, we investigated the effects of specific fatty acids included in RJ (RJ fatty acids), such as 10-hydroxy-2-decenoic acid, 10-hydroxydecanoic acid, and sebacic acid (SA), on expression of ANGPTL8 in human hepatoma HepG2 cells. SA markedly reduced the expression of ANGPTL8. Reporter assay revealed that SA suppressed ANGPTL8 promoter activity. In addition, we identified a functional binding site of hepatocyte nuclear factor-4α (HNF4α), a liver-enriched transcription factor, in the ANGPTL8 promoter. SA reduced the levels of HNF4α protein and the binding of HNF4α to the ANGPTL8 promoter. Moreover, siRNA knockdown of HNF4α suppressed the expression of ANGTPL8 mRNA. Taken together, we conclude that SA downregulates ANGPTL8 expression via the decrease in HNF4α protein.

Changes in mRNA and protein levels of gonadotropin releasing hormone and receptor in ovine thymus, lymph node, spleen, and liver during early pregnancy

There exists maternal immunological modification in maternal immune organs during early pregnancy in mammals. Gonadotropin releasing hormone (GnRH) is widely distributed in vertebrate tissues, including immune organs. However, it is unclear that early pregnancy induces expression of GnRH and GnRH receptor (GnRHR) in ovine immune organs. The objective of this study was to explore the expression of GnRH and GnRHR in main immune organs (thymus, lymph node, spleen, and liver) during early pregnancy in sheep. Ovine thymus, lymph node, spleen and liver were sampled at day 16 of estrous cycle, and days 13, 16, and 25 of pregnancy. The expression of GnRH and GnRHR was detected through real-time quantitative PCR, Western blot and immunohistochemistry analysis. The results indicated that early pregnancy induced upregulation of mRNA and protein levels of GnRH and GnRHR in the maternal lymph node, spleen and liver, and mRNA and protein of GnRH in the maternal thymus, but mRNA and protein of GnRHR decreased in the maternal thymus during early pregnancy. In summary, the mRNA and protein levels of GnRH and GnRHR were changed in maternal thymus, lymph node, spleen and liver in a tissue specific manner during early pregnancy in sheep.

Expression of melatonin receptors and CD4 in the ovine thymus, lymph node, spleen and liver during early pregnancy

As a pineal gland hormone, melatonin acts through its receptors to modulate the immune system. The immune system is composed of primary and secondary organs, and immune organs are adapted to the presence of the fetal alloantigen during pregnancy. However, it is unclear whether melatonin affects maternal immune organs during early pregnancy in sheep. In this study, the ovine thymus, lymph node, spleen and liver were sampled at day 16 of the oestrous cycle, and at days 13, 16 and 25 of pregnancy. The expression of melatonin receptor 1A (MT1), melatonin receptor 1B (MT2) and cluster of differentiation 4 (CD4) was detected by quantitative real-time polymerase chain reaction, Western blot and immunohistochemistry experiments. Our results showed that during early pregnancy there was an upregulation of MT1 mRNA and protein in the thymus, lymph node and liver, and there was a downregulation in the spleen. The expression of MT2 mRNA and protein was increased in the thymus but decreased in the spleen and liver, and there was no significant change in the lymph node during early pregnancy. CD4 protein was upregulated in the thymus, lymph node and liver, but there were no significant changes in the spleen during early pregnancy. In conclusion, early pregnancy induces tissue-specific expression of MT1, MT2 and CD4, which may be due to the different functions of the thymus, lymph node, spleen and liver. Further, melatonin is involved in immune regulation of the maternal thymus, lymph node, spleen and liver during early pregnancy in sheep.

The concomitant loss of APC and HNF4α in adult hepatocytes does not contribute to hepatocarcinogenesis driven by β-catenin activation

BACKGROUND & AIMS

Loss of hepatocyte nuclear factor-4α (HNF4α), a critical factor driving liver development and differentiation, is frequently associated with hepatocellular carcinoma (HCC). Our recent data revealed that HNF4α level was decreased in mouse and human HCCs with activated β-catenin signalling. In addition, increasing HNF4α level by miR-34a inhibition slowed tumour progression of β-catenin-activated HCC in mice.

METHODS

We generated a Hnf4aflox/flox/ Apcflox/flox /TTR-CreERT2 (Hnf4a/Apc∆Hep ) mouse line and evaluated the impact of Hnf4a disruption on HCC development and liver homoeostasis.

RESULTS

There was no significant impact of Hnf4a disruption on tumour onset and progression in Apc∆Hep model. However, we observed an unexpected phenotype in 28% of Hnf4a∆Hep mice maintained in a conventional animal facility, which presented disorganized portal triads, characterized by stenosis of the portal vein and increased number and size of hepatic arteries and bile ducts. These abnormal portal structures resemble the human idiopathic non-cirrhotic portal hypertension syndrome. We correlated the presence of portal remodelling with a higher expression of protein and mRNA levels of TGFβ and BMP7, a key regulator of the TGFβ-dependent endothelial-to-mesenchymal transition.

CONCLUSION

These data demonstrate that HNF4α does not play a major role during β-catenin-driven HCC, thus revealing that the tumour suppressor role of HNF4α is far more complex and dependent probably on its temporal expression and tumour context. However, HNF4α loss in adult hepatocytes could induce abnormal portal structures resembling the human idiopathic non-cirrhotic portal hypertension syndrome, which may result from endothelial- and epithelial-to-mesenchymal transitions.

Genome-wide prediction of cis-regulatory regions using supervised deep learning methods

Background

In the human genome, 98% of DNA sequences are non-protein-coding regions that were previously disregarded as junk DNA. In fact, non-coding regions host a variety of cis-regulatory regions which precisely control the expression of genes. Thus, Identifying active cis-regulatory regions in the human genome is critical for understanding gene regulation and assessing the impact of genetic variation on phenotype. The developments of high-throughput sequencing and machine learning technologies make it possible to predict cis-regulatory regions genome wide.

Results

Based on rich data resources such as the Encyclopedia of DNA Elements (ENCODE) and the Functional Annotation of the Mammalian Genome (FANTOM) projects, we introduce DECRES based on supervised deep learning approaches for the identification of enhancer and promoter regions in the human genome. Due to their ability to discover patterns in large and complex data, the introduction of deep learning methods enables a significant advance in our knowledge of the genomic locations of cis-regulatory regions. Using models for well-characterized cell lines, we identify key experimental features that contribute to the predictive performance. Applying DECRES, we delineate locations of 300,000 candidate enhancers genome wide (6.8% of the genome, of which 40,000 are supported by bidirectional transcription data), and 26,000 candidate promoters (0.6% of the genome).

Conclusion

The predicted annotations of cis-regulatory regions will provide broad utility for genome interpretation from functional genomics to clinical applications. The DECRES model demonstrates potentials of deep learning technologies when combined with high-throughput sequencing data, and inspires the development of other advanced neural network models for further improvement of genome annotations.

Electronic supplementary material

The online version of this article (10.1186/s12859-018-2187-1) contains supplementary material, which is available to authorized users.

Metabolic modulation of acetaminophen-induced hepatotoxicity by osteopontin

Induction of osteopontin (OPN), a well-known pro-inflammatory molecule, has been observed in acetaminophen (APAP)-induced hepatotoxicity. However, the precise cell source for OPN induction and its role during APAP-induced hepatotoxicity has not been fully explored. By employing a hepatotoxic mouse model induced by APAP overdose, we demonstrate that both serum and hepatic OPN levels were significantly elevated in response to APAP treatment. Our in vivo and in vitro studies clearly indicated that the induced expression of hepatic OPN was mainly located in necrosis areas and produced by dying or dead hepatocytes. Functional experiments showed that OPN deficiency protected against the APAP-induced liver injury by inhibiting the toxic APAP metabolism via reducing the expression of the cytochrome P450 family 2 subfamily E member 1 (CYP2E1). Interestingly, this inhibition of CYP2E1 expression did not occur in unfasted Opn^-/- mice, but was significant in fasted Opn^-/- mice and maintained for 2 hours after APAP challenge in fasted Opn^-/- mice. In addition, despite the early protective role of OPN deficiency on APAP-induced hepatotoxicity, OPN deficiency retarded injury resolution by sensitizing hepatocytes to apoptosis and impairing liver regeneration. Finally, we demonstrated that a siRNA-mediated transient hepatic Opn knockdown could sufficiently and significantly protect animals from APAP-induced hepatotoxicity and death. In conclusion, this study clearly defines the cell source of OPN induction in response to APAP treatment, provides a novel insight into the metabolic role of OPN to APAP overdose, and suggests an Opn-targeted therapeutic strategy for the treatment or prevention of APAP-induced hepatotoxicity.

Microenvironment and tumor cells: two targets for new molecular therapies of hepatocellular carcinoma

Hepatocellular carcinoma (HCC), is one of the most frequent human cancer and is characterized by a high mortality rate. The aggressiveness appears strictly related to the liver pathological background on which cancer develops. Inflammation and the consequent fibro/cirrhosis, derived from chronic injuries of several origins (viral, toxic and metabolic) and observable in almost all oncological patients, represents the most powerful risk factor for HCC and, at the same time, an important obstacle to the efficacy of systemic therapy. Multiple microenvironmental cues, indeed, play a pivotal role in the pathogenesis, evolution and recurrence of HCC as well as in the resistance to standard therapies observed in most of patients. The identification of altered pathways in cancer cells and of microenvironmental changes, strictly connected in pathogenic feedback loop, may permit to plan new therapeutic approaches targeting tumor cells and their permissive microenvironment, simultaneously.

Apoptosis signal-regulating kinase 1 mediates the inhibitory effect of hepatocyte nuclear factor-4α on hepatocellular carcinoma

Previous studies provided substantial evidence of a striking suppressive effect of hepatocyte nuclear factor 4α (HNF4α) on hepatocellular carcinoma (HCC). Apoptosis signal-regulating kinase 1 (ASK1) is involved in death receptor-mediated apoptosis and may acts as a tumor suppressor in hepatocarcinogenesis. However, the status and function of ASK1 during HCC progression are unclear. In this study, we found that HNF4α increased ASK1 expression by directly binding to its promoter. ASK1 expression was dramatically suppressed and correlated with HNF4α levels in HCC tissues. Reduced ASK1 expression was associated with aggressive tumors and poor prognosis for human HCC. Moreover, ASK1 inhibited the malignant phenotype of HCC cells in vitro. Intratumoral ASK1 injection significantly suppressed the growth of subcutaneous HCC xenografts in nude mice. More interestingly, systemic ASK1 delivery strikingly inhibited the growth of orthotopic HCC nodules in NOD/SCID mice. In addition, inhibition of endogenous ASK1 partially reversed the suppressive effects of HNF4α on HCC. Collectively, this study highlights the suppressive effect of ASK1 on HCC and its biological significance in HCC development. These outcomes broaden the knowledge of ASK1 function in HCC progression, and provide a novel potential prognostic biomarker and therapeutic target for advanced HCC.

A cross-species approach to identify transcriptional regulators exemplified for Dnajc22 and Hnf4a

There is an enormous need to make better use of the ever increasing wealth of publicly available genomic information and to utilize the tremendous progress in computational approaches in the life sciences. Transcriptional regulation of protein-coding genes is a major mechanism of controlling cellular functions. However, the myriad of transcription factors potentially controlling transcription of any given gene makes it often difficult to quickly identify the biological relevant transcription factors. Here, we report on the identification of Hnf4a as a major transcription factor of the so far unstudied DnaJ heat shock protein family (Hsp40) member C22 (Dnajc22). We propose an approach utilizing recent advances in computational biology and the wealth of publicly available genomic information guiding the identification of potential transcription factor candidates together with wet-lab experiments validating computational models. More specifically, the combined use of co-expression analyses based on self-organizing maps with sequence-based transcription factor binding prediction led to the identification of Hnf4a as the potential transcriptional regulator for Dnajc22 which was further corroborated using publicly available datasets on Hnf4a. Following this procedure, we determined its functional binding site in the murine Dnajc22 locus using ChIP-qPCR and luciferase assays and verified this regulatory loop in fruitfly, zebrafish, and humans.

Bisphenol A Disrupts HNF4α-Regulated Gene Networks Linking to Prostate Preneoplasia and Immune Disruption in Noble Rats

Exposure of humans to bisphenol A (BPA) is widespread and continuous. The effects of protracted exposure to BPA on the adult prostate have not been studied. We subjected Noble rats to 32 weeks of BPA (low or high dose) or 17β-estradiol (E2) in conjunction with T replenishment. T treatment alone or untreated groups were used as controls. Circulating T levels were maintained within the physiological range in all treatment groups, whereas the levels of free BPA were elevated in the groups treated with T+low BPA (1.06 ± 0.05 ng/mL, P < .05) and T+high BPA (10.37 ± 0.43 ng/mL, P < .01) when compared with those in both controls (0.1 ± 0.05 ng/mL). Prostatic hyperplasia, low-grade prostatic intraepithelial neoplasia (PIN), and marked infiltration of CD4+ and CD8+ T cells into the PIN epithelium (P < .05) were observed in the lateral prostates (LPs) of T+low/high BPA-treated rats. In contrast, only hyperplasia and high-grade PIN, but no aberrant immune responses, were found in the T+E2-treated LPs. Genome-wide transcriptome analysis in LPs identified differential changes between T+BPA vs T+E2 treatment. Expression of multiple genes in the regulatory network controlled by hepatocyte nuclear factor 4α was perturbed by the T+BPA but not by the T+E2 exposure. Collectively these findings suggest that the adult rat prostate, under a physiologically relevant T environment, is susceptible to BPA-induced transcriptomic reprogramming, immune disruption, and aberrant growth dysregulation in a manner distinct from those caused by E2. They are more relevant to our recent report of higher urinary levels BPA found in patients with prostate cancer than those with benign disease.

Biological characteristics of the A1762T/G1764A mutant strain of hepatitis B virus in vivo

The double nucleotide, A1762T and G1764A exchange (TA mutation), in the hepatitis B virus (HBV) genome basal core promoter (BCP) region is a common viral mutation in patients with chronic HBV infection. This mutation is located in the binding site of hepatocyte nuclear factor 4 (HNF4), and a number of liver‑enriched transcription factors are involved in the regulation of HBV transcription and replication. The aim of the present study was to investigate the biological characteristics of the HBV strain with this mutation, and the effect of HNF4 inhibition on the replication of this strain in vivo. The results indicated that in vivo the HBV strain with the TA mutation supported a higher level of pregenomic RNA transcription and HBV DNA replication, compared with the wild‑type strain. Furthermore, the concentration of serum HBeAg in the TA mutant group was lower than that in the wild‑type strain. Following treatment of the mice with entecavir (ETV) or tenofovir disoproxil fumarate (TDF), the transcription and replication levels of wild‑type and mutant strains were reduced. In the groups treated with TDF, the inhibition effect was more marked. In hepatocytes in which HNF4 expression was specifically inhibited, the level of 3.5 kb mRNA of HBV was reduced compared with that in mouse cells with normal HNF4 expression, and HBV DNA replication levels were also reduced to a greater extent. Furthermore, following liver‑specific knockdown of HNF4, the reduction in variant virus expression was greater than that of the wild‑type virus. In conclusion, the replication capacity of HBV with the TA mutation was increased, and the mutation was associated with a reduction in serum HBeAg levels. This mutant strain remained sensitive to ETV and TDF, and HNF4 supported a higher replication level of TA mutant HBV in vivo.

MicroRNA-34c is associated with emphysema severity and modulates SERPINE1 expression

BACKGROUND

MicroRNAs (MiRNA) are small non-coding RNAs that regulate gene expression. The aim of this study was to identify miRNAs differentially expressed between mild and moderately emphysematous lung, as well as their functional target mRNAs. Resected lung from patients with COPD undergoing lung cancer surgery was profiled using miRNA (Agilent Human miRNA profiler G4470 V1.01) and mRNA (OperonV2.0) microarrays. Cells of lung origin (BEAS-2B and HFL1) were profiled using mRNA microarrays (Illumina HumanHT-12 V3) after in vitro manipulation.

RESULTS

COPD patients had mean (SD) age 68 (6) years, FEV1 72 (17)% predicted and gas transfer (KCO) 70 (10)% predicted. Five miRNAs (miR-34c, miR-34b, miR-149, miR-133a and miR-133b) were significantly down-regulated in lung from patients with moderate compared to mild emphysema as defined by gas transfer (p < 0.01). In vitro upregulation of miR-34c in respiratory cells led to down-regulation of predicted target mRNAs, including SERPINE1, MAP4K4, ZNF3, ALDOA and HNF4A. The fold change in ex-vivo expression of all five predicted target genes inversely correlated with that of miR-34c in emphysematous lung, but this relationship was strongest for SERPINE1 (p = 0.05).

CONCLUSION

Differences in miRNA expression are associated with emphysema severity in COPD patients. MiR-34c modulates expression of its putative target gene, SERPINE1, in vitro in respiratory cell lines and ex vivo in emphysematous lung tissue.

Hepatocyte nuclear factor 4-alpha involvement in liver and intestinal inflammatory networks

Hepatocyte nuclear factor 4-alpha (HNF4-α) is a nuclear receptor regulating metabolism, cell junctions, differentiation and proliferation in liver and intestinal epithelial cells. Mutations within the HNF4A gene are associated with human diseases such as maturity-onset diabetes of the young. Recently, HNF4A has also been described as a susceptibility gene for ulcerative colitis in genome-wide association studies. In addition, specific HNF4A genetic variants have been identified in pediatric cohorts of Crohn’s disease. Results obtained from knockout mice supported that HNF4-α can protect the intestinal mucosae against inflammation. However, the exact molecular links behind HNF4-α and inflammatory bowel diseases remains elusive. In this review, we will summarize the current knowledge about the role of HNF4-α and its isoforms in inflammation. Specific nature of HNF4-α P1 and P2 classes of isoforms will be summarized. HNF4-α role as a hepatocyte mediator for cytokines relays during liver inflammation will be integrated based on documented examples of the literature. Conclusions that can be made from these earlier liver studies will serve as a basis to extrapolate correlations and divergences applicable to intestinal inflammation. Finally, potential functional roles for HNF4-α isoforms in protecting the intestinal mucosae from chronic and pathological inflammation will be presented.

JunD/AP1 regulatory network analysis during macrophage activation in a rat model of crescentic glomerulonephritis

Background

Function and efficiency of a transcription factor (TF) are often modulated by interactions with other proteins or TFs to achieve finely tuned regulation of target genes. However, complex TF interactions are often not taken into account to identify functionally active TF-targets and characterize their regulatory network. Here, we have developed a computational framework for integrated analysis of genome-wide ChIP-seq and gene expression data to identify the functional interacting partners of a TF and characterize the TF-driven regulatory network. We have applied this methodology in a rat model of macrophage dependent crescentic glomerulonephritis (Crgn) where we have previously identified JunD as a TF gene responsible for enhanced macrophage activation associated with susceptibility to Crgn in the Wistar-Kyoto (WKY) strain.

Results

To evaluate the regulatory effects of JunD on its target genes, we analysed data from two rat strains (WKY and WKY.LCrgn2) that show 20-fold difference in their JunD expression in macrophages. We identified 36 TFs interacting with JunD/Jun and JunD/ATF complexes (i.e., AP1 complex), which resulted in strain-dependent gene expression regulation of 1,274 target genes in macrophages. After lipopolysaccharide (LPS) stimulation we found that 2.4 fold more JunD/ATF-target genes were up-regulated as compared with JunD/Jun-target genes. The enriched 314 genes up-regulated by AP1 complex during LPS stimulation were most significantly enriched for immune response (P = 6.9 × 10^-4) and antigen processing and presentation functions (P = 2.4 × 10^-5), suggesting a role for these genes in macrophage LPS-stimulated activation driven by JunD interaction with Jun/ATF.

Conclusions

In summary, our integrated analyses revealed a large network of TFs interacting with JunD and their regulated targets. Our data also suggest a previously unappreciated contribution of the ATF complex to JunD-mediated mechanisms of macrophage activation in a rat model of crescentic glomerulonephritis.

Genomic characterization of remission in juvenile idiopathic arthritis

Introduction

The attainment of remission has become an important end point for clinical trials in juvenile idiopathic arthritis (JIA), although we do not yet have a full understanding of what remission is at the cell and molecular level.

Methods

Two independent cohorts of patients with JIA and healthy child controls were studied. RNA was prepared separately from peripheral blood mononuclear cells (PBMC) and granulocytes to identify differentially expressed genes using whole genome microarrays. Expression profiling results for selected genes were confirmed by quantitative, real-time polymerase chain reaction (RT-PCR).

Results

We found that remission in JIA induced by either methotrexate (MTX) or MTX plus a TNF inhibitor (etanercept, Et) (MTX + Et) is characterized by numerous differences in gene expression in peripheral blood mononuclear cells and in granulocytes compared with healthy control children; that is, remission is not a restoration of immunologic normalcy. Network analysis of the differentially expressed genes demonstrated that the steroid hormone receptor superfamily member hepatocyte nuclear factor 4 alpha (HNF4α) is a hub in several of the gene networks that distinguished children with arthritis from controls. Confocal microscopy revealed that HNF4a is present in both T lymphocytes and granulocytes, suggesting a previously unsuspected role for this transcription factor in regulating leukocyte function and therapeutic response in JIA.

Conclusions

These findings provide a framework from which to understand therapeutic response in JIA and, furthermore, may be used to develop strategies to increase the frequency with which remission is achieved in adult forms of rheumatoid arthritis.

Micro-RNAs in inflammatory diseases and as a link between inflammation and cancer

OBJECTIVE

The objective of this review is to examine the role of miRNA in various inflammatory diseases and in inflammatory diseases progressing to cancer.

INTRODUCTION

MicroRNAs are small, conserved, non-coding RNA molecules which are present in most of the eukaryotes. miRNA have been reported to play a major role in the physiological control of gene expression and in the pathogenesis of various diseases. They regulate the gene expression mainly at the post-transcriptional level. miRNA expression profile is reported to be altered in various inflammatory diseases and subsequently affects the expression of genes, which is important in disease pathogenesis.

METHODS

A Pubmed database search was performed for studies related to miRNA studies in inflammatory disease, cancer and in inflammatory diseases progressing to cancer.

CONCLUSION

The evidence shows very important role of miRNA in inflammatory diseases. Few miRNAs involved in common inflammatory process and suggest miRNA as a link between inflammation and cancer. Future research should be directed to use miRNA therapeutically to target common inflammatory pathway and to develop miRNA as biomarker to detect development of cancer at early stages.

MicroRNA-feedback loop as a key modulator of liver tumorigenesis and inflammation

A recent work of Iliopoulos et al published in Cell highlighted a circuit orchestrated by microRNAs (miRNAs) that results in liver tumorigenesis and inflammation. This feedback loop, governed by miR-24 and miR-629, promotes a hepatocyte nuclear factor-4α transient inhibition resulting in miR-124 induction and signal transducer and activator of transcription 3 activation. These promising data support the use of miRNA mimics or inhibitors as potent therapeutic approaches in liver cancer.

The role of microRNAs in hepatocyte nuclear factor-4alpha expression and transactivation

Hepatocyte nuclear factor (HNF)-4α is a key member of the transcription factor network regulating hepatocyte differentiation and function. Genetic and molecular evidence suggests that expression of HNF-4α is mainly regulated at the transcriptional level. Activation of HNF-4A gene involves the interaction of distinct sets of transcription factors and co-transcription factors within enhancer and promoter regions. Here we study the inhibitory effect of microRNAs (miRNAs) on the 3'-untranslated region (3'-UTR) of HNF-4A mRNA. The potential recognition elements of a set of miRNAs were identified utilizing bioinformatics analysis. The family members of miR-34 and miR-449, including miR-34a, miR-34c-5p and miR-449a, share the same target elements located at two distinct locations within the 3'-UTR of HNF-4A. The over-expression of miR-34a, miR-34c-5p or miR-449a in HepG2 cells led to a significant decrease in the activity of luciferase reporter carrying 3'-UTR of HNF-4A. The repressive effect on reporter activity was partially or fully eliminated when one or two of the binding site(s) for miR-34a/miR-34c-5p/miR-449a were deleted within the 3'-UTR. The protein level of HNF-4α was dramatically reduced by over-expression of miR-34a, miR-34c-5p and miR-449a, which correlates with a decrease in the binding activity of HNF-4α and transactivation of HNF-4α target genes. These results suggest that the recognition sites of miR-34a, miR-34c-5p and miR-449a within 3'-UTR of HNF-4A are functional. The mechanism of down-regulation of the binding activity and transactivation of HNF-4α by the miRNAs involves the decrease in HNF-4α protein level via miRNAs selectively targeting HNF-4A 3'-UTR, leading to the translational repression of HNF-4α expression.

Inhibiting the expression of hepatocyte nuclear factor 4 alpha attenuates lipopolysaccharide/D-galactosamine-induced fulminant hepatic failure in mice

BACKGROUND

Hepatocyte nuclear factor 4 alpha (HNF4alpha) plays an important role in regulating cytokine-induced inflammatory responses. This study aimed to investigate the role of HNF4alpha in the development of fulminant hepatic failure (FHF) induced by lipopolysaccharide/D-galactosamine (LPS/D-GalN).

METHODS

The FHF model was induced by simultaneous intraperitoneal injection of LPS/D-GalN in mice. Three days prior to LPS/D-GalN administration, HNF4alpha short-hairpin interfering RNA expression plasmid or physiological saline was injected via the tail vein with a hydrodynamics-based procedure. The degree of hepatic damage and cumulative survival rate were subsequently assessed.

RESULTS

The expression of HNF4alpha was increased in the early stage after LPS/D-GalN administration. Inhibiting the expression of HNF4alpha reduced serum levels of alanine aminotransferase and aspartate aminotransferase, alleviated histological injury, and improved the survival of mice with FHF. In addition, both serum and hepatic tumor necrosis factor alpha expression were suppressed when HNF4alpha expression was inhibited in mice with FHF.

CONCLUSION

Inhibiting HNF4alpha expression protects mice from FHF induced by LPS/D-GalN, but the exact mechanism behind this needs further investigation.

Spherical cell shape of FLC-4 cell, a human hepatoma cell, enhances hepatocyte-specific function and suppresses tumor phenotype through the integration of mRNA-microRNA interaction

The induction mechanism of HNF-4α by spherical cell shape in human hepatoma cells, FLC-4, was investigated. To get insight into the induction mechanism of HNF-4α in three-dimensional FLC-4 cells, mRNA microarray analysis was performed. The gene expression related to drug metabolism and nuclear receptors, such as LXRα, was elevated in spherical FLC-4 cells. We found the first time that the expressions of genes related to malignancy of hepatoma cells, such as HIF-1α, c-Myc and VEGFC, were downregulated by spherical cell shape. Network analysis revealed that HNF-4α would elicit both the enhancement of hepatocyte-specific gene expression and suppression of malignancy. Since HNF-4α gene expression was known to be regulated by microRNA, we inferred that spherical cell shape would induce HNF-4α gene expression through microRNA. To investigate the possibility of such a mechanism, mRNA–microRNA interactions were examined using microRNA microarray and bioinformatics analysis. The level of miR-24, a microRNA targeting HNF-4α, was reduced in spherical FLC-4 cells. On the other hand, spherical cell shape-induced miR-194 and miR-320c would directly downregulate SLC7A5 and E2F1 gene expression, respectively, which are both related to malignancy. Our study suggested that spherical cell shape would induce HNF-4α gene expression and consequent enhancement hepatocyte-specific functions. Spherical cell shape itself would suppress malignancy in FLC-4 cells through microRNA, such as miR-194 and miR-320c.

Mucroporin-M1 inhibits hepatitis B virus replication by activating the mitogen-activated protein kinase (MAPK) pathway and down-regulating HNF4α in vitro and in vivo

Hepatitis B virus (HBV) is a noncytopathic human hepadnavirus that causes acute, chronic hepatitis and hepatocellular carcinoma (HCC). As the clinical utility of current therapies is limited, new anti-HBV agents and sources for such agents are still highly sought after. Here, we report that Mucroporin-M1, a scorpion venom-derived peptide, reduces the amount of extracellular HBsAg, HBeAg, and HBV DNA productions of HepG2.2.15 cells in a dose-dependent manner and inhibits HBV capsid DNA, HBV intracellular RNA replication intermediates and the HBV Core protein in the cytoplasm of HepG2.2.15 cells. Using a mouse model of HBV infection, we found that HBV replication was significantly inhibited by intravenous injection of the Mucroporin-M1 peptide. This inhibitory activity was due to a reduction in HBV promoter activity caused by a decrease in the binding of HNF4α to the precore/core promoter region. Furthermore, we confirmed that Mucroporin-M1 could selectively activate mitogen-activated protein kinases (MAPKs) and lead to the down-regulation of HNF4α expression, which explains the decreased binding of HNF4α to the HBV promoter. Moreover, when the protein phosphorylation activity of the MAPK pathway was inhibited, both HNF4α expression and HBV replication recovered. Finally, we proved that treatment with the Mucroporin-M1 peptide increased phosphorylation of the MAPK proteins in HBV-harboring mice. These results implicate Mucroporin-M1 peptide can activate the MAPK pathway and then reduce the expression of HNF4α, resulting in the inhibition of HBV replication in vitro and in vivo. Our work also opens new doors to discovering novel anti-HBV agents or sources.

Inhibition of hepatitis B Virus replication by hepatocyte nuclear factor 4-alpha specific short hairpin RNA

BACKGROUND

Previous studies showed that hepatocyte nuclear factor 4α (HNF4α) may play a critical role in hepatitis B virus (HBV) replication.

AIMS

This study aimed to investigate the effect of knocking down of HNF4α with RNA interference technique on HBV replication in a HBV replication mouse model.

METHODS

Four HNF4α, specific short hairpin RNA (shRNA)-producing plasmids were constructed. HBV mRNA and DNA replication intermediates were analysed using Northern and Southern blot respectively. The expression of HNF4α and HBV core antigen (HBcAg) was detected using immunohistochemistry technique.

RESULTS

One of the HNF4α shRNAs, HNF4α shRNA1, efficiently inhibited the expression of HNF4α in HepG2 cells and mice liver. HBV RNA transcripts and DNA replication intermediates in HNF4α shRNA1 group were decreased 67.3 and 76%, respectively, in HepG2 cells, and 68.1 and 70.6% in mice liver respectively. The expression level of HBcAg in the liver was also decreased with the inhibition of HNF4α expression.

CONCLUSIONS

These results suggested that decreasing of HNF4α expression was associated with the reduced level of HBV replication in HepG2 cells and mice liver. These data indicated that HNF4α played a critical role in HBV replication in vivo, and HNF4α shRNA could inhibit HBV replication in vivo.

Study of the expression levels of Hepatocyte nuclear factor 4 alpha and 3 beta in patients with different outcome of HBV infection

Hepatocyte nuclear factors 4 alpha (HNF4α) and 3 beta (HNF3β) are members of a group of liver-enriched transcription factors (LETFs) that play important roles in regulating the replication of hepatitis B virus (HBV) and liver inflammation. However, the relationship of the level of HNF4α and HNF3β with the severity of HBV-infected liver diseases is unclear. In this study, liver tissue samples from different types of HBV patients were collected, and HNF4α and HNF3β expression were detected by immunohistochemistry. The expression of HNF4α was significant higher in patients with severe hepatitis B(SHB) than those with chronic hepatitis B(CHB) and liver cirrhosis(LC) (both P < 0.05), but similar between patients with CHB and LC (P > 0.05). And the expression of HNF3β was similar among patients with CHB, LC and SHB (P > 0.05 for all pairwise comparison). This suggests that the expression level of HNF4α was different in patients with different outcome of HBV infection, high expression level of HNF4α may correlate with occurrence of SHB