Bletilla striata polysaccharides alleviate metabolic dysfunctionassociatedsteatotic liver disease through enhancing hepatocyteRelA/HNF1αsignal

BACKGROUND Bletilla striata polysaccharides(BSP)have antioxidant,immune regulation,and anti-fibrotic activities.However,the therapeutic effect and mechanisms underlying the action of BSP in metabolic dysfunction-associated steatotic liver disease(MASLD)have not been fully understood.AIMTo investigate the therapeutic effects and mechanisms of BSP on MASLD by centering on the hepatocyte nuclearfactor kappa B p65(RelA)/hepatocyte nuclear factor-1 alpha(HNF1α)signaling.METHODSA mouse model of MASLD was induced by feeding with a high-fat-diet(HFD)and a hepatocyte model of steatosiswas induced by treatment with sodium oleate(SO)and sodium palmitate(SP).The therapeutic effects of BSP onMASLD were examined in vivo and in vitro.The mechanisms underlying the action of BSP were analyzed for theireffect on lipid metabolism disorder,endoplasmic reticulum(ER)stress,and the RelA/HNF1αsignaling.RESULTSHFD feeding reduced hepatocyte RelA and HNF1αexpression,induced ER stress,lipid metabolism disorder,andnecroptosis in mice,which were significantly mitigated by treatment with BSP.Furthermore,treatment with BSP orBSP-containing conditional rat serum significantly attenuated the sodium oleate/sodium palmitate(SO/SP)-induced hepatocyte steatosis by decreasing lipid accumulation,and lipid peroxidation,and enhancing theexpression of RelA,and HNF1α.The therapeutic effects of BSP on MASLD were partially abrogated by RELAsilencing in mice and RELA knockout in hepatocytes.RELA silencing or knockout significantly down-regulatedHNF1αexpression,and remodeled ER stress and oxidative stress responses during hepatic steatosis.CONCLUSIONTreatment with BSP ameliorates MASLD,associated with enhancing the RelA/HNF1αsignaling,remodeling ERstress and oxidative stress responses in hepatocytes.

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.

Roles of hepatocyte nuclear factors in hepatitis B virus infection

Approximately 350 million people are estimated to be persistently infected with hepatitis B virus(HBV) worldwide. HBV maintains persistent infection by employing covalently closed circular DNA(ccc DNA), a template for all HBV RNAs. Chronic hepatitis B(CHB) patients are currently treated with nucleos(t)ide analogs such as lamivudine, adefovir, entecavir, and tenofovir. However, these treatments rarely cure CHB because they are unable to inhibit ccc DNA transcription and inhibit only a late stage in the HBV life cycle(the reverse transcription step in the nucleocapsid). Therefore, an understanding of the factors regulating ccc DNA transcription is required to stop this process. Among numerous factors, hepatocyte nuclear factors(HNFs) play the most important roles in ccc DNA transcription, especially in the generation of viral genomic RNA, a template for HBV replication. Therefore, proper control of HNF function could lead to the inhibition of HBV replication. In this review, we summarize and discuss the current understanding of the roles of HNFs in the HBV life cycle and the upstream factors that regulate HNFs. This knowledge will enable the identification of new therapeutic targets to cure CHB.

Role of hepatocyte nuclear factor 4-alpha in gastrointestinal and liver diseases

Hepatocyte nuclear factor 4-alpha(HNF4α)is a highly conserved member of nuclear receptor superfamily of ligand-dependent transcription factors that is expressed in liver and gastrointestinal organs(pancreas,stomach,and intestine).In liver,HNF4αis best known for its role as a master regulator of liver-specific gene expression and essential for adult and fetal liver function.Dysregulation of HNF4αexpression has been associated with many human diseases such as ulcerative colitis,colon cancer,maturity-onset diabetes of the young,liver cirrhosis,and hepatocellular carcinoma.However,the precise role of HNF4αin the etiology of these human pathogenesis is not well understood.Limited information is known about the role of HNF4αisoforms in liver and gastrointestinal disease progression.There is,therefore,a critical need to know how disruption of the expression of these isoforms may impact on disease progression and phenotypes.In this review,we will update our current understanding on the role of HNF4αin human liver and gastrointestinal diseases.We further provide additional information on possible use of HNF4αas a target for potential therapeutic approaches.

Hepatocyte nuclear factor 4α induces a tendency of differentiation and activation of rat hepatic stellate cells

AIM: To investigate the effect of hepatocyte nuclear factor 4α(HNF4α) on the differentiation and transformation of hepatic stellate cells(HSCs).METHODS: By constructing the recombinant adenovirus vector expressing HNF4α and HNF4αshRNA vector, and manipulating HNF4α expression in HSC-T6 cells, we explored the influence of HNF4α and its induction capacity in the differentiation of rat HSCs into hepatocytes.RESULTS: With increased expression of HNF4αmediated by AdHNF4α, the relative expression of Nanog was downregulated in HSC-T6 cells(98.33 ±12.33 vs 41.33 ± 5.67, P < 0.001). Consequently, the expression of G-P-6 and PEPCK was upregulated(G-P-6:14.34 ± 3.33 vs 42.53 ± 5.87, P < 0.01; PEPCK: 10.10± 4.67 vs 56.56 ± 5.25, P < 0.001), the expression of AFP and ALB was positive, and the expression of Nanog, Type Ⅰ collagen, α-SMA, and TIMP-1 was significantly decreased. HNF4α also downregulated vimentin expression and enhanced E-cadherin expression. The ultrastructure of HNF4α-induced cells had more mitochondria and ribosomes compared with the parental cells. After silencing HNF4α expression,EPCK, E-cadherin, AFP, and ALB were downregulated and α-SMA and vimentin were upregulated.CONCLUSION: HNF4α can induce a tendency of differentiation of HSCs into hepatocyte-like cells. These findings may provide an effective way for the treatmentof liver diseases.

Regulation of hepatic micro RNA expression by hepatocyte nuclear factor 4 alpha

AIMTo uncover the role of hepatocyte nuclear factor 4 alpha (HNF4α) in regulating hepatic expression of microRNAs. METHODSMicroarray and real-time PCR were used to determine hepatic expression of microRNAs in young-adult mice lacking Hnf4α expression in liver (Hnf4α-LivKO). Integrative genomics viewer software was used to analyze the public chromatin immunoprecipitation-sequencing datasets for DNA-binding of HNF4α, RNA polymerase-II, and histone modifications to loci of microRNAs in mouse liver and human hepatoma cells. Dual-luciferase reporter assay was conducted to determine effects of HNF4α on the promoters of mouse and human microRNAs as well as effects of microRNAs on the untranslated regions (3’UTR) of two genes in human hepatoma cells. RESULTSMicroarray data indicated that most microRNAs remained unaltered by Hnf4α deficiency in Hnf4α-LivKO mice. However, certain liver-predominant microRNAs were down-regulated similarly in young-adult male and female Hnf4α-LivKO mice. The down-regulation of miR-101, miR-192, miR-193a, miR-194, miR-215, miR-802, and miR-122 as well as induction of miR-34 and miR-29 in male Hnf4α-LivKO mice were confirmed by real-time PCR. Analysis of public chromatin immunoprecipitation-sequencing data indicates that HNF4α directly binds to the promoters of miR-101, miR-122, miR-194-2/miR-192 and miR-193, which is associated with histone marks of active transcription. Luciferase reporter assay showed that HNF4α markedly activated the promoters of mouse and human miR-101b/miR-101-2 and the miR-194/miR-192 cluster. Additionally, miR-192 and miR-194 significantly decreased activities of luciferase reporters for the 3’UTR of histone H3F3 and chromodomain helicase DNA binding protein 1 (CHD1), respectively, suggesting that miR-192 and miR-194 might be important in chromosome remodeling through directly targeting H3F3 and CHD1. CONCLUSIONHNF4α is essential for hepatic basal expression of a group of liver-enriched microRNAs, including miR-101, miR-192, miR-193a, miR-194 and miR-802, through which HNF4α may play a major role in the post-transcriptional regulation of gene expression and maintenance of the epigenome in liver.

Berberine retarded the growth of gastric cancer xenograft tumors by targeting hepatocyte nuclear factor 4α

BACKGROUND Gastric cancer is the third deadliest cancer in the world and ranks second in incidence and mortality of cancers in China.Despite advances in prevention,diagnosis,and therapy,the absolute number of cases is increasing every year due to aging and the growth of high-risk populations,and gastric cancer is still a leading cause of cancer-related death.Gastric cancer is a consequence of the complex interaction of microbial agents,with environmental and host factors,resulting in the dysregulation of multiple oncogenic and tumor-suppressing signaling pathways.Global efforts have been made to investigate in detail the genomic and epigenomic heterogeneity of this disease,resulting in the identification of new specific and sensitive predictive and prognostic biomarkers.Trastuzumab,a monoclonal antibody against the HER2 receptor,is approved in the first-line treatment of patients with HER2+tumors,which accounts for 13%-23%of the gastric cancer population.Ramucirumab,a monoclonal antibody against VEGFR2,is currently recommended in patients progressing after first-line treatment.Several clinical trials have also tested novel agents for advanced gastric cancer but mostly with dis-appointing results,such as anti-EGFR and anti-MET monoclonal antibodies.Therefore,it is still of great significance to screen specific molecular targets for gastric cancer and drugs directed against the molecular targets.AIM To investigate the effect and mechanism of berberine against tumor growth in gastric cancer xenograft models and to explore the role of hepatocyte nuclear factor 4α(HNF4α)-WNT5a/β-catenin pathways played in the antitumor effects of berberine.METHODS MGC803 and SGC7901 subcutaneous xenograft models were established.The control group was intragastrically administrated with normal saline,and the berberine group was administrated intragastrically with 100 mg/kg/d berberine.The body weight of nude mice during the experiment was measured to assess whether berberine has any adverse reaction.The volume of subcutaneous tumors during this experiment was recorded to evaluate the inhibitory effect of berberine on the growth of MGC803 and SGC7901 subcutaneous transplantation tumors.Polymerase chain reaction assays were conducted to evaluate the alteration of transcriptional expression of HNF4α,WNT5a andβ-catenin in tumor tissues and liver tissues from the MGC803 and SGC7901 xenograft models.Western blotting and IHC were performed to assess the protein expression of HNF4α,WNT5a andβ-catenin in tumor tissues and liver tissues from the MGC803 and SGC7901 xenograft models.RESULTS In the both MGC803 and SGC7901 xenograft tumor models,berberine significantly reduced tumor volume and weight and thus retarded the growth rate of tumors.In the SGC7901 and MGC803 subcutaneously transplanted tumor models,berberine down-regulated the expression of HNF4α,WNT5a andβ-catenin in tumor tissues from both transcription and protein levels.Besides,berberine also suppressed the protein expression of HNF4α,WNT5a andβ-catenin in liver tissues.CONCLUSION Berberine retarded the growth of MGC803 and SGC7901 xenograft model tumors,and the mechanism behind these anti-growth effects might be the downregulation of the expression of HNF4α-WNT5a/β-catenin signaling pathways both in tumor tissues and liver tissues of the xenograft models.

Hepatocyte nuclear factor 1B mutation in a Chinese family with renal cysts and diabetes syndrome:A case report

BACKGROUND Renal cysts and diabetes(RCAD)syndrome is an autosomal dominant diabetic renal disease.Precise molecular diagnosis of RCAD syndrome has proven valuable for understanding its mechanism and personalized therapy.CASE SUMMARY A RCAD patient and her family were studied to investigate potential responsible genes by the whole exome sequencing(WES).Candidate pathogenic variants were validated by Sanger sequencing.The clinical characteristics of RCAD patient were collected from medical records.Unlike those typical RCAD patients,we observed renal manifestation and prediabetes phenotype,but not reproductive organ phenotype and hypomagnesaemia.A novel 7-bp deletion mutation in exon 4 of the hepatocyte nuclear factor 1B,NM_000458:c.882_888del(p.V294fs),was identified by WES and confirmed by Sanger sequencing.CONCLUSION This novel mutation identified in a Chinese family with RCAD syndrome might be the molecular pathogenic basis of this disorder.

Association of A Common Haplotype of Hepatocyte Nuclear Factor 1α With Type 2 Diabetes in Chinese Population

Objective To analyze the association of variants of hepatocyte nuclear factor-1α （HNF-1α） gene with type 2 diabetes in Chinese population. Methods In 152 unrelated type 2 diabetes patients and 93 unrelated controls, eleven single nucleotide polymorphisms （SNPs） were identified and genotyped. Statistical analyses were performed to investigate whether these SNPs were associated with diabetes status in our samples. Results In the individual SNP study, no SNP differed significantly in frequency between type 2 diabetes patients and controls. In the haplotype analysis, two haplotype blocks were identified. In haplotype block 1, no evidence was found between common HNF-1α haplotypes and type 2 diabetes. However, in haplotype block 2, a common haplotype GCGC formed by four tagging SNPs （tSNPs） was found to be associated with decreased risk of type 2 diabetes （odds ratio [OR] 0.6011, 95% confidence interval [CI] 0.4138-0.8732, P=0.0073, empirical P=0.0511, permutation test）. A similar trend was also observed in the diplotype analysis, indicating that the increasing copy number of the haplotype GCGC was associated with the decreased frequency of diabetes （P=0.0193）. Conclusion The results of this study provide evidence that the haplotype of HNF-1α decreases the risk of type 2 diabetes in Chinese individuals.

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 (HNF4α) plays an important role in regulating cytokine-induced inflammatory responses. This study aimed to investigate the role of HNF4α 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, HNF4α 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 HNF4α was increased in the early stage after LPS/D-GalN administration. Inhibiting the expression of HNF4α 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 HNF4α expression was inhibited in mice with FHF. CONCLUSION: Inhibiting HNF4α expression protects mice from FHF induced by LPS/D-GalN, but the exact mechanism behind this needs further investigation.

Unexpected discovery of 2 cases of hepatocyte nuclear factor 1α-mutated infracentimetic adenomatosis

We present 2 cases of hepatocyte nuclear factor 1α (HNF1α)-mutated adenomatosis, discovered for reasons unrelated to this disease, and identified using immunohistochemical methods. These new tools may further our understanding of the link between adenomas/adenomatosis subtypes and their complications, and their association with other abnormalities.

Metformin attenuates angiotensin II induced cardiac fibrosis and transforming growth factor-β1 production through the inhibition of hepatocyte nuclear factor4

Aim In diabetic patients, metformin appears to provide cardiovascular protection that cannot be attribu- ted only to its antihyperglycemic effects. Metformin is also known as the AMP-activated protein kinase （AMPK） ac- tivator. Our previous study suggested that metformin inhibits transforming growth factor-β1 （TGF-β1） production in a mouse heart failure model of pressure overload. TGF-β1 is a key factor in cardiac fibrosis and is usually induced by Angiotensin Ⅱ （Ang Ⅱ ） in the pressure overload mouse models. This study investigated the effect of metformin on cardiac fibrosis and TGF-β production induced by AngII and the underlying mechanisms. Methods C57/BL6 wild-type and AMPKα2 knockout mice were used. AngII （3 mg · kg-1 · d-1） was infused subcutaneously into mice for 7 days. Adult mouse cardiac fibroblasts were isolated and treated with AngII （ 1 μmol · L-1） and/or met- formin （1 mmol · L-l）. Results In C57/BL6 mice, metformin inhibits AngII-induced cardiac fibrosis. In cardi-ac fibroblasts, metformin inhibits TGF-β1 expression and production induced by AngII. AMPK inhibitor, com- pound C, reversed the effects of metformin. In vivo, AMPKα2 deficiency further increases AngII-induced TGF-β1 production. In cardiac fibroblasts, metformin inhibited AngII induced hepatocyte nuclear factor4 （HNF4ot protein level increase and HNF4α binding with TGF-β1 promoter using chromatin immunoprecipitation assay. In vivo, AMPKα2 deficiency further increased AngII-induced HNF4α protein level. Using HNF4α adenovirus, overexpress- ing HNF4α led to a 1.5-fold increase in TGF-β1 mRNA expression. HNF4a siRNA blocked AngII induced TGF- β1 production. Luciferase reporter with deleted HNF4a binding sites showed decreased TGFbl transcriptional activ- ity induced by AngII. In AMPK or2-/- heart, the inhibition of metformin on HNF4a protein was attenuated. Con- clusion Metformin inhibits AngII induced cardiac fibrosis and TGF-β1 production through AMPK activation. The underlying mechanism is that AMPK activation inhibits AngII induced HNF4α and then decreases TGF-β1 expres- sion.

Expression of hepatocyte nuclear factor 4 alpha,wingless-related integration site,andβ-catenin in clinical gastric cancer

BACKGROUND Gastric cancer(GC)is the second most common cause of cancer-related deaths worldwide.Hepatocyte nuclear factor 4 alpha(HNF4α)that belongs to the nuclear hormone receptor superfamily,is overexpressed in GC tissues,and might be involved in the development of GC by regulating its downstream winglessrelated integration site(WNT)/β-catenin signaling.AIM To clarify the expression of HNF4α/WNT5a/β-catenin signaling proteins in clinical GC tissues.METHODS We immunohistochemically stained pathological blocks of GC and matched paracancerous tissues.The intensity of HNF4α,WNT5a andβ-catenin staining in the tumor cells was determined according to cell rates and staining intensity.The correlations between GC and HNF4α,WNT5a,andβ-catenin expression using chisquare and paired chi-square tests.Relationships between double-positive HNF4αand WNT5a expression and types of gastric tumor tissues were assessed using regression analysis.Correlations between HNF4αand WNT5a expression at the RNA level in GC tissues found in the TCGA database were analyzed using Pearson correlation coefficients.RESULTS We found more abundant HNF4αand WNT5a proteins in GC,especially in mucinous adenocarcinoma and mixed GC than in adjacent tissues(P<0.001).Low and high levels of cytoplasmicβ-catenin respectively expressed in GC and adjacent tissues(P<0.001)were not significantly associated with pathological parameters.CONCLUSION The expressions of HNF4αand WNT5a could serve as early diagnostic biomarkers for GC.

Corticosteroid-induced bradycardia in multiple sclerosis and maturity-onset diabetes of the young due to hepatocyte nuclear factor 4-alpha mutation:A case report

BACKGROUND Intravenous steroid pulse therapy is the treatment of choice for acute exacerbation of multiple sclerosis(MS).Although steroid administration is generally welltolerated,cases of cardiac arrhythmia have been reported.Herein,we describe a young woman who developed marked sinus bradycardia and T-wave abnormalities after corticosteroid administration.We also present plausible explanations for the abnormalities observed in this patient.CASE SUMMARY An 18-year-old woman experienced vertiginous dizziness and binocular diplopia 1 wk prior to admission.Neurological examination revealed left internuclear ophthalmoplegia with left peripheral-type facial palsy.The initial laboratory results were consistent with those of type 2 diabetes.Brain magnetic resonance imaging revealed multifocal,non-enhancing,symptomatic lesions and multiple enhancing lesions.She was diagnosed with MS and maturity-onset diabetes of the young.Intravenous methylprednisolone was administered.On day 5 after methylprednisolone infusion,marked bradycardia with T-wave abnormalities were observed.Genetic evaluation to elucidate the underlying conditions revealed a hepatocyte nuclear factor 4-alpha(HNF4A)gene mutation.Steroid treatment was discontinued under suspicion of corticosteroid-induced bradycardia.Her electrocardiogram changes returned to normal without complications two days after steroid discontinuation.CONCLUSION Corticosteroid-induced bradycardia may have a significant clinical impact,especially in patients with comorbidities,such as HNF4A mutations.

Role of Hepatocyte Nuclear Factor 4α in Regulating Hepatic Differentiation and the Inflammatory Response in HCC

Limited treatment options are available for hepatocellular carcinoma(HCC),especially in the advanced stage,which is associated with a poor prognosis.Many studies have demonstrated that hepatocyte nuclear factor 4α(HNF 4α)plays an important role in hepatic differentiation and the carcinogenesis of HCC.HNF 4αcritically regulates hepatic differentiation by controlling a large number of genes involved in hepatic functions including metabolism,xenobiotic detoxification,bile acid synthesis,and serum protein production.It has also been confirmed to play an important role in the inflammatory environment in HCC.Thus,HNF 4αis considered to be a promising target for the treatment of HCC.Some studies have demonstrated that regulating HNF 4αexpression in HCC had beneficial effects in in vivo and in vitro experiments.We herein review the role of HNF 4αin regulating hepatic metabolism and the inflammatory response,aiming to provide some ideas on induced hepatic differentiation therapy and regulating the inflammatory microenvironment for the treatment of advanced HCC.

Generation of functional hepatocyte-like cells from human bone marrow mesenchymal stem cells by overexpression of transcription factor HNF4α and FOXA2

Background: Our previous study showed that overexpression of hepatocyte nuclear factor 4α(HNF4α) could directly promote mesenchymal stem cells(MSCs) to differentiate into hepatocyte-like cells. However, the efficiency of hepatic differentiation remains low. The purpose of our study was to establish an MSC cell line that overexpressed HNF4α and FOXA2 genes to obtain an increased hepatic differentiation efficiency and hepatocyte-like cells with more mature hepatocyte functions. Methods: Successful establishment of high-level HNF4α and FOXA2 co-overexpression in human induced hepatocyte-like cells(hi Hep cells) was verified by flow cytometry, immunofluorescence and RT-PCR. Measurements of albumin(ALB), urea, glucose, indocyanine green(ICG) uptake and release, cytochrome P450(CYP) activity and gene expression were used to analyze mature hepatic functions of hi Hep cells. Results: hi Hep cells efficiently express HNF4α and FOXA2 genes and proteins, exhibit typical epithelial morphology and acquire mature hepatocyte-like cell functions, including ALB secretion, urea production, ICG uptake and release, and glycogen storage. hi Hep cells can be activated by CYP inducers. The percentage of both ALB and α-1-antitrypsin(AAT)-positive cells was approximately 72.6%. The expression levels of hepatocyte-specific genes( ALB, AAT, and CYP1A1) and liver drug transport-related genes( ABCB1, ABCG2, and SLC22A18) in hi Hep cells were significantly higher than those in MSCs-Vector cells. The hi Hep cells did not form tumors after subcutaneous xenograft in BALB/c nude mice after 2 months. Conclusion: This study provides an accessible, feasible and efficient strategy to generate hi Hep cells from MSCs.

Facilitating effects of berberine on rat pancreatic islets through modulating hepatic nuclear factor 4 alpha expression and glucokinase activity

AIM： To observe the effect of berberine on insulin secretion in rat pancreatic islets and to explore its possible molecular mechanism. METHODS： Pdmary rat islets were isolated from male Sprague-Dawley rats by collagenase digestion and treated with different concentrations （1, 3, 10 and 30 μmol/L） of berberine or 1 μmol/L Glibenclamide （GB） for 24 h. Glucose-stimulated insulin secretion （GSIS） assay was conducted and insulin was determined by radioimmunoassay. 3-（4,5-Dimethylthiazol-2-yl）- 2,5-diphenyltetrazolium bromide （MTT） assay was performed to evaluate cytotoxicity. The mRNA level of hepatic nuclear factor 4 alpha （HAIF4α） was determined by reverse transcription polymerase chain reaction （RT-PCR）. Indirect immunofluorescence staining and Western blot analysis were employed to detect protein expression of HNF4α in the islets. Glucokinase （GK） activity was measured by spectrophotometric method. RESULTS： Berberine enhanced GSIS rather than basal insulin secretion dose-dependently in rat islets and showed no significant cytotoxicity on islet cells at the concentration of 10 μmol/L. Both mRNA and protein expressions of HNF4α were up-regulated by berberine in a dose-dependent manner, and GK activity was also increased accordingly. However, GB demonstrated no regulatory effects on HNF4α expression or GK activity. CONCLUSION： Berberine can enhance GSIS in rat islets, and probably exerts the insulinotropic effect via a pathway involving HNF4α and GK, which is distinct from sulphonylureas （SUs）.

Disrupted NF-κB activation after partial hepatectomy does not impair hepatocyte proliferation in rats

AIM： To analyze the effects of NF-kB inhibition by antioxidant pyrrolidine dithiocarbamate （PDTC） or TNF inhibitor pentoxifylline （PTX） on liver regeneration after partial hepatectomy （PH）. METHODS： Saline, PDTC or PTX were injected 1 h before PH and rats were killed at 0.5 and 24 h after PH. Several control groups were used for comparison （injection control groups）. RESULTS： Compared to saline injected controls, NF-kB activation was absent 0.5 h after PH in rats treated with PDTC or PTX. At 24 h after PH, DNA synthesis and PCNA expression were identical in treated and control rats and thus occurred irrespectively of the status of NF-kB activation at 0.5 h. Signal transducer and activator of transcription 3 （Stat3） acUvatJon was observed already 0.5 h after PH in saline, PDTC or PTX group and was similar to Stat3 activation in response to injection without PH. CONCLUSION： These data strongly suggest that （1） NF-kB p65/p50 DNA binding produced in response to PH is not a signal necessary to initiate the liver regeneration, （2） star3 activation is a stress response unrelated to the activation of NF-kB. In conclusion, NF-kB activation is not critically required for the process of liver regeneration after PH.

Hepatocyte nuclear factor 4α in the pathogenesis of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is emerging as the most common chronic liver disease worldwide. It refers to a range of liver conditions affecting people who drink little or no alcohol. NAFLD comprises non-alcoholic fatty liver and non-alcoholic steatohepatitis (NASH), the more aggressive form of NAFLD. NASH is featured by steatosis, lobular inflammation, hepatocyte injury, and various degrees of fibrosis. Although much progress has been made over the past decades, the pathogenic mechanism of NAFLD remains to be fully elucidated. Hepatocyte nuclear factor 4α (HNF4α) is a nuclear hormone receptor that is highly expressed in hepatocytes. Hepatic HNF4α expression is markedly reduced in NAFLD patients and mouse models of NASH. HNF4α has been shown to regulate bile acid, lipid, glucose, and drug metabolism. In this review, we summarize the recent advances in the understanding of the pathogenesis of NAFLD with a focus on the regulation of HNF4α and the role of hepatic HNF4α in NAFLD. Several lines of evidence have shown that hepatic HNF4α plays a key role in the initiation and progression of NAFLD. Recent data suggest that hepatic HNF4α may be a promising target for treatment of NAFLD.

The interplay between hepatocyte nuclear factor 4α(HNF4α)and cholesterol sulfotransferase(SULT2B1b)in hepatic energy homeostasis

The nuclear receptor hepatocyte nuclear factor 4alpha(HNF4α)plays a critical role in the regulation of metabolic homeostasis,including glucose homeostasis.Sulfotransferases(SULTs)catalyze the transfer of a sulfate group from 3-phosphoadenosine 5-phosphosulfate(PAPS)to an acceptor molecule.Sulfonation plays an essential role in regulating the chemical and functional homeostasis of endogenous and exogenous molecules.Among SULTs,the cholesterol sulfotransferase 2B1b(SULT2B1b)preferentially catalyzes the sulfoconjugation of cholesterol and oxysterols to form cholesterol sulfate and oxysterol sulfates.Hepatic gluconeogenesis represents a critical component of energy metabolism.Although there have been reviews on the regulation of glucose homeostasis by HNF4a,the interplay between HNF4a and SULT2B1b in hepatic glucose homeostasis remains scattered.In this review,we intend to provide an overview on how HNF4a functionally cross-talks with SULT2B1b to regulate hepatic glucose homeostasis and whether the HNF4a-SULT2B1b axis represents a novel therapeutic target for the management of metabolic liver disease and metabolic syndrome.