Effect of Compound Phyllanthus urinaria Ⅱ on Growth and Expression of miR-122 and IGF-1R of Hepatocellular Carcinoma Hep3B Cells in Nude Mice / 中国实验方剂学杂志

ObjectiveTo investigate the inhibitory effects and mechanism of the compound Phyllanthus urinaria Ⅱ （CPU Ⅱ）on the growth of transplanted hepatocellular carcinoma Hep3B2.1-7 （Short for Hep3R） cells in nude mice. MethodAfter the establishment of a xenograft model of hepatocellular carcinoma Hep3B cells in mice， the model mice were randomly divided into a model group， a high-dose CPU Ⅱ group （57.5 g·kg-1）， a low-dose CPU Ⅱ group （28.75 g·kg-1）， and a 5-fluorouracil （5-FU） group （0.025 g·kg-1）， with eight mice in each group. The mice in the high- and low-dose CPU Ⅱ groups were treated with drugs by gavage， once per day， and those in the model group were treated with the same volume of normal saline. The mice in the 5-FU group were treated by 5-FU by intraperitoneal injection， once every other day. After 28 days of administration， mice were sacrificed， and transplanted tumors were collected. Immunohistochemistry （IHC） was used to detect the expression of proliferating cell nuclear antigen （PCNA） of tumor tissues. Terminal-deoxynucleotidyl transferase-mediated nick end labeling （TUNEL） was used to detect cell apoptosis of tumor tissues. The mRNA expression of miR-122 and insulin-like growth factor 1 receptor （IGF-1R） in tumor tissues was detected by Real-time quantitative PCR （Real-time PCR）. The protein expression of CCAAT/enhancer-binding protein α （C/EBPα）， hepatocyte nuclear factor-4α （HNF-4α）， and IGF-1R in tumor tissues was detected by Western blot. ResultThe tumor suppression rates of the high- and low-dose CPU Ⅱ groups and the 5-FU group were 74.90%， 63.62%， and 64.15%， respectively. Compared with the model group， the CPU Ⅱ groups and the 5-FU group showed reduced weight （P<0.01） and volume of tumors （P<0.01）， decreased PCNA positive cells， shallow staining， increased apoptosis cells of transplanted tumor tissues （P<0.05， P<0.01）， increased expression of mRNA expression of miR-122 （P<0.01）， down-regulated mRNA expression of IGF-1R （P<0.01）， and up-regulated protein expression of C/EBPα and HNF-4α in nude mouse transplanted tumor tissues （P<0.01）. The expression of IGF-1R protein in the high-dose CPU Ⅱ group was down-regulated （P<0.05）. Compared with the low-dose CPU Ⅱ group， the high-dose CPU Ⅱ group showed increased apoptotic cells （P<0.01）， up-regulated mRNA expression of miR-122 （P<0.01）， and increased expression of C/EBPα and HNF-4α proteins （P<0.01）. ConclusionCPU Ⅱ has an obvious inhibitory effect on the growth of transplanted hepatocellular carcinoma Hep3B cells in nude mice. The mechanism of action is related to enhancing the expression of transcription factors HNF-4α and C/EBPα， thereby promoting the expression of miR-122 and inhibiting the expression of its target gene IGF-1R.

Research progress on sex hormone-binding globulin involved in the occurrence and development of diabetes mellitus / 中国基层医药

Sex hormone-binding globulin (SHBG) is significantly associated with abnormal glucose metabolism. Low SHBG level is a risk factor for insulin resistance and the occurence of diabetes mellitus. SHBG is negatively correlated with the risk of type 2 diabetes mellitus and plays an important role in regulating insulin resistance while predicting its development. The genotype of SHBG has been found to be closely related to the occurrence of diabetes mellitus. Fatty liver and DNA methylation are also important factors mediating the relationship between SHBG and type 2 diabetes mellitus. The change in SHBG level may be related to insulin resistance by influencing hepatocyte nuclear factor 4a and regulating glucose transporter.

PXR activation impairs hepatic glucose metabolism partly via inhibiting the HNF4α-GLUT2 pathway

Drug-induced hyperglycemia/diabetes is a global issue. Some drugs induce hyperglycemia by activating the pregnane X receptor (PXR), but the mechanism is unclear. Here, we report that PXR activation induces hyperglycemia by impairing hepatic glucose metabolism due to inhibition of the hepatocyte nuclear factor 4-alpha (HNF4α)‒glucose transporter 2 (GLUT2) pathway. The PXR agonists atorvastatin and rifampicin significantly downregulated GLUT2 and HNF4α expression, and impaired glucose uptake and utilization in HepG2 cells. Overexpression of PXR downregulated GLUT2 and HNF4α expression, while silencing PXR upregulated HNF4α and GLUT2 expression. Silencing HNF4α decreased GLUT2 expression, while overexpressing HNF4α increased GLUT2 expression and glucose uptake. Silencing PXR or overexpressing HNF4α reversed the atorvastatin-induced decrease in GLUT2 expression and glucose uptake. In human primary hepatocytes, atorvastatin downregulated GLUT2 and HNF4α mRNA expression, which could be attenuated by silencing PXR. Silencing HNF4α downregulated GLUT2 mRNA expression. These findings were reproduced with mouse primary hepatocytes. Hnf4α plasmid increased Slc2a2 promoter activity. Hnf4α silencing or pregnenolone-16α-carbonitrile (PCN) suppressed the Slc2a2 promoter activity by decreasing HNF4α recruitment to the Slc2a2 promoter. Liver-specific Hnf4α deletion and PCN impaired glucose tolerance and hepatic glucose uptake, and decreased the expression of hepatic HNF4α and GLUT2. In conclusion, PXR activation impaired hepatic glucose metabolism partly by inhibiting the HNF4α‒GLUT2 pathway. These results highlight the molecular mechanisms by which PXR activators induce hyperglycemia/diabetes.

Role and mechanisms of hepatocyte nuclear factor 4α in bile acid induced gastric intestinal metaplasia / 中华消化杂志

Objective To investigate the roles and mechanisms of hepatocyte nuclear factor 4α (HNF4α) in chenodeoxycholic acid (CDCA) induced gastric intestinal metaplasia (IM).Methods After the immortalized gastric mucosal epithelial cells GES-1 were stimulated with CDCA at different concentration,the changes of HNF4α,caudal-related homeobox 2 (CDX2) and trefoil factor family 3 (TFF3) expressions at mRNA and protein levels in GES-1 cells and gastric cancer cell lines (AGS,SGC7901 and BGC823) were detected by real time-polymerase chain reaction (RT-PCR) and Western blotting.After GES-1 were transfected with HNF4α short hairpin RNA (shRNA) or control shRNA,and followed by CDCA stimulation,the expressions of HNF4α,CDX2 and TFF3 at protein level were determined by Western blotting.HNF4α was overexpressed in GES-1 cells and SGC7901 cells,and HNF4α was silenced in BGC823 cell line and AGS by lentiviral vector system.The expressions of HNF4α,CDX2 and TFF3 at mRNA and protein levels were tested by RT-PCR and Western blotting.Luciferase reporter assay was used to analyze the regulation role of HNF4α on CDX2.T test was performed for statistical analysis.Results The expressions of HNF4α in GES-1,SGC7901,BGC823 and AGS cells at mRNA level were 1.00 ± 0.12,263.01±10.23,848.01±18.13 and 3 049.86±91.75,respectively.The mRNAlevels of HNF4α in AGS,BGC823 and SGC7901 cells were all higher than that of GES-1 cells,and the differences were statistically significant (t=33.23,46.72 and 25.62,all P＜0.01).The expressions of HNF4α in GES-1,SGC7901,BGC823 and AGS at protein level were consistent with mRNA level.The expressions of CDX2 and TFF3 at protein level of HNF4α shRNA transfected group were lower than those of non-HNF4α shRNA transfected group.In GES-1 cells,the expressions of HNF4α,CDX2 and TFF3 of HNF4α overexpressed group at mRNA level were 16 281.839 ± 1 843.017,6.275 ± 0.137 and 17.310± 1.533,respectively;which were all higher than those of overexpressed control group (1.000 ± 0.048,1.000 ± 0.012 and 1.000±0.108,respectively),and the differences were statistically significant (t =8.83,38.29 and 10.61,all P＜0.01).In AGS cells,the expressions of HNF4α,CDX2 and TFF3 of HNF4α silenced group at mRNA level were 0.021 ± 0.001,0.088 ± 0.007 and 0.074 ± 0.002,respectively,which were lower than those of silenced control group (1.000 ± 0.108,1.000 ± 0.131 and 1.000 ± 0.122),and the differences were statistically significant (t=9.09,6.93 and 7.57,all P＜0.01).In GES-1 overexpressed cells and AGS silenced cells,the expressions of HNF4α,CDX2,TFF3 at protein level were consistent with mRNA level.In double reporter plasmid containing the CDX2 promoter CDX2 1 (-2 000～-1 bp) and CDX2-2 (-1 510～1 bp),after transfected with HNF4α shRNA,the activities were 0.387 ± 0.013 and 0.533 ± 0.040,respectively,which were lower than those of HNF4α shRNA transfected control group (0.605 ± 0.012 and 0.882 ± 0.019),and the differences were statistically significant (t =21.49 and 13.53,both P＜0.01).Conclusion HNF4α may be involved in bile acid induced intestinal metaplasia by upregulating the expression of CDX2.

Induction study of CYP3A2 in male rats by zolmitriptan / 药学学报

In our preliminary studies, we observed zolmitriptan (ZOL) treatment led to induction of CYP3A2 in male not female rats. To figure out the reason is of great significance for drug-drug interactions and personalized administration. Since growth hormone (GH) is known as the major mechanistic determinant of sexually-dimorphic gene expression like CYP3A2 in rat liver, the impacts of ZOL on both plasma GH levels in non monosodium glutamate (MSG)-treated rats and CYP3A2 expression in GH depleted MSG-treated rats were studied. ZOL was shown to partially suppress GH levels in both genders. Furthermore, CYP3A2 protein and mRNA level declined in male not female MSG-treated rats. In order to study the possible molecular events involved in the depression of GH and gender-selective induction on rat CYP3A2 by ZOL, the mRNA and protein level (whole protein and nuclear protein) of hepatocyte nuclear factor 4α (HNF4α) was investigated. Nuclear accumulation of HNF4α was observed in the normal male not female rat liver tissue following ZOL treatment. However, this kind of nuclear translocation did not occur in rat hepatocytes and MSG-treated rats. These findings demonstrated CYP3A2 inducibility by ZOL was gender-selective. GH and HNF4α may play an important role in CYP3A2 induction.

Establishment of a reporter gene system for activity detection of hepatocyte nuclear factor 4α / 第二军医大学学报

Objective To establish a luciferase reporter gene system for detecting the activity of hepatocyte nuclear factor 4α (HNF4α), so as to screen the small molecule compounds regulating the activity of HNF4α. Methods HNF4α was purified by affinity chromatography. The direct interaction of DNA fragment or small molecule compounds to the HNF4α was determined by protein thermal shift assay. The constructing recombinant plasmid pGL3-NINJ1-3p or pGL3-NINJ1-9p, which contained three copies or nine copies of the HNF4α response element in the Ninjurin 1 (NINJ1) promoter, was transfected into hepatoma carcinoma cells. The transcriptional activity of HNF4α was detected by dual-luciferase reporter gene assay. The expressions of HNF4α and its down-stream genes were analyzed in hepatoma carcinoma cells treated with small molecular compound luteolin or alverine by real-time quantitative PCR. The changes of HNF4α transcriptional activity of cells treated with luteolin or alverine were estimated by luciferase reporter gene assay. Results Protein thermal shift confirmed that the HNF4α response element in NINJ1 promoter bound to HNF4α protein. In the hepatoma carcinoma cells with overexpression of HNF4α, both pGL3-NINJ1-3p and pGL3-NINJ1-9p could detect the alteration of the transcriptional activity of HNF4α, and pGL3-NINJ1-9p was more sensitive than pGL3-NINJ1-3p (P<0.01). Luteolin and alverine, both directly interacting with HNF4α, down-regulated and up-regulated the expression of HNF4α target genes, respectively. Moreover, pGL3-NINJ1-9p could validate the effect of luteolin or alverine on the transcriptional activity of HNF4α. Conclusion We successfully establish a detection system for HNF4α activity in hepatoma carcinoma cells by the reporter gene vector pGL3-NINJ1-9p. This system is a tool for screening small molecule compounds that regulate HNF4α activity.

Hepatocyte Nuclear Factor 4α Inhibits Expression of Vascular Endothelial Growth Factor in Human Hepatocellular Carcinoma Cell Lines and Tube Formation of Human Umbilical Vein Endothelial Cell / 胃肠病学

Background: Hepatocyte nuclear factor 4α (HNF4α) plays an important role in the development of liver,and studies demonstrate that it is correlated with the pathogenesis of hepatocellular carcinoma (HCC).However,the regulatory effect of HNF4α on expression of vascular endothelial growth factor (VEGF) in human HCC cell lines and tube formation of human umbilical vein endothelial cell (HUVEC) is not yet clear.Aims: To investigate the effect of HNF4α on expression of VEGF in human HCC cell lines and tube formation of HUVEC.Methods: Lentiviral vector overexpressed HNF4α was constructed,and then transfected into HepG2 and SMMC-7721 cells (experimental group),cells transfected with lentiviral blank vector and cells without transfection were served as negative control group and blank control group,respectively.The mRNA and protein expressions of HNF4α,VEGF were detected by qRT-PCR and Western blotting,respectively.The conditioned media of HepG2 and SMMC-7721 cells were co-cultured with HUVEC,and number of HUVEC tube formation was measured.Results: HepG2 and SMMC-7721 cells with stable overexpression of HNF4α were successfully established.Compared with negative control group and blank control group,mRNA and protein expressions of VEGF in experimental group were significantly decreased (P＜0.05),and number of HUVEC tube formation was significantly decreased (P＜0.05).Conclusions: HNF4α can significantly inhibit the expression of VEGF in HepG2 and SMMC-7721 cells and tube formation of HUVEC.

The role of hepatocyte nuclear factor 4 alpha in development and progression of liver diseases / 临床肝胆病杂志

Hepatocyte nuclear factor 4 alpha (HNF4α), a member of the nuclear receptor superfamily, has a high expression level in mature hepatocytes. HNF4α can regulate hepatocyte-specific gene expression at a transcriptional level, promote hepatocyte development and differentiation, participate in establishment and maintenance of hepatocyte polarity, and enhance the synthetic, metabolic, and detoxifying functions of the liver. Through inhibiting the activation of hepatic stellate cells, reversing epithelial-mesenchymal transition, and inhibiting the proliferation, invasion, and metastasis of hepatoma cells, HNF4α may be involved in the development and progression of various liver diseases including liver fibrosis, liver cirrhosis, and hepatocellular carcinoma. This paper elaborates on the biological functions of HNF4α, and summarizes and analyzes the research advances in the mechanisms of action of HNF4α in the pathological process of liver diseases, in order to provide references for further investigation of the potential targeted therapies for liver diseases.

Inhibitory effect of PEP-1-mediated recombinant hepatocyte nuclear factor 4 alpha transduction on hepatocellular carcinoma cells / 第二军医大学学报

Objective To investigate cell penetrating peptide (PEP-1)-mediated transduction of recombinant hepatocyte nuclear factor 4 alpha (HNF4α) protein into hepatocellular carcinoma (HCC) cells, and to observe the effect of the fusion protein P-HNF4α on HCC cells. Methods The expression vector pET28a-P-HNF4α was constructed. The prokaryotic expression condition of fusion protein P-HNF4α was optimized. Recombinant P-HNF4α carrying cell penetrating peptide PEP-1 was obtained by abundant expression, purified by affinity chromatography, and was concentrated and dialyzed. P-HNF4α was transduced into HCC cells. The transduction efficiency was analyzed by Western blotting analysis. Sub-cellular localization of P-HNF4α was detected by Western blotting analysis with nuclear and cytoplasmic extracts and confirmed by immunofluorescence assay. Real-time RT-PCR was used to examine the gene expression of HCC cells. The proliferation of HCC cells was detected with CCK-8 kit. The migration and invasion of HCC cells were detected by wound-healing assay and trans-well invasion assay, respectively. Results P-HNF4α was efficiently transduced into Huh7 cells and located in the nucleus as mediated by PEP-1. P-HNF4α significantly up-regulated the expression of characteristic hepatocyte markers and down-regulated the "stemness" genes in Huh7 cells (P<0.05 or P<0.01). Moreover, the proliferation (P<0.05), migration (P<0.001) and invasion (P<0.05) of HCC cells were significantly suppressed by fusion protein P-HNF4α. Conclusion P-HNF4α can induce the differentiation of HCC cells to mature hepatocytes and reduce the malignancy phenotype of HCC cells, suggesting that PEP-1-mediated HNF4α protein transduction may be a potential strategy for HCC differentiation therapy.

Protection of Sophocarpine on Colonic Barrier in DSS-induced Acute Colitis in Mice by Increasing Expression of HNF4α / 中草药·英文版

Objective: To investigate the possible protective effects of sophocarpine on mucosal injury and epithelial barrier disruption on dextran sulfate sodium (DSS)-induced acute colitis. Methods: Male BALB/c mice were randomly divided into three groups. The mice in normal group were given normal water, and those in model and sophocarpine-treated groups were given 2.5% DSS for 6 d to induce acute colitis. Sophocarpine (30 mg/kg) was ip administered once daily during the study period. Severity of colitis was evaluated by disease activity index (DAI), histological injury and inflammatory cytokine production including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and monocyte chemoattractant protein-1 (MCP-1). The colonic barrier disruption was assessed by testing the expression of junctional adhesion molecule-1 (JAM-1), E-cadherin (E-CAD), and desmocollin-2 (DSC-2) in colon mucosa. Expression of HNF4α in colon mucosa was detected by immunohistochemistry staining and real-time RT-PCR, respectively. Results: Compared with normal group, DAI, colonic shortening, and histopathological injury in model group were elevated (P < 0.05), but reduced in sophocarpine-treated group (P < 0.05). Compared with model group, the mRNA expression of inflammatory cytokines (TNF-α, IL-1β, MCP-1) were obviously lower in sophocarpine-treated group (P < 0.05), while the cellular junction proteins (E-CAD, JAM-1, and DSC-2) were higher (P < 0.05). The expression of HNF4α at mRNA and protein levels was decreased significantly in model group, but increased apparently in sophocarpine-treated group. Conclusion: Sophocarpine can enhance the expression of HNF4α, promote the expression of colonic intrecellular junctions, thus, maintain the integrity of the colonic barrier and inhibit the colitis process. We suggest that sophocarpine could enhance the production of cellular junction proteins to protect the intestinal barrier fuction, at least partly, in HNF4α-dependent pathway.

Clinical significance of hepatocyte nuclear factor 4αin rectal cancer and its relationship with prognosis / 国际肿瘤学杂志

Objective To investigate the clinical significance of hepatocyte nuclear factor 4α(HNF4α)in rectal cancer and its relationship with prognosis.Methods Real-time PCR was designed to detect the expression of HNF4αon mRNA level and the immunohistochemistry was used to determine the expression of HNF4αon protein level in rectal cancer tissue.The relationship between HNF4αexpression and clinical characteristics was also analysed.The Kaplan-Meier method was used for univariate analysis and a Cox proportional hazards regression model was performed for multivariate analysis.Results HNF4αwas low expressed both on mRNA (t=6.092,P<0.001)and protein level (χ2 =15.230,P<0.001)in rectal cancer tissue.HNF4αexpression on protein level was related with the clinical stage (χ2 =48.311,P<0.001),depth of invasion (χ2 =23.911,P<0.001),histological differentiation (χ2 =20.787,P<0.001),lymph node metastasis (χ2 =39.064,P<0.001)and distant metastasis (χ2 =5.146,P=0.04),while age and gender were not relevant.The cumulative 3-year overall survival of patients with low HNF4αexpression (43.8%)was much worse than the patients with high HNF4αexpression (95 .5%),and the difference was statistically sig-nificant (P<0.001).Univariate analysis revealed that HNF4αexpression (χ2 =28.778,P<0.001),differ-entiation (χ2 =26.680,P<0.001 ),clinical stage (χ2 =32.702,P<0.001 ),depth of invasion (χ2 =6.226,P=0.013),lymph node invasion (χ2 =15.270,P<0.001)and distant metastasis (χ2 =21.817, P<0.001)were statistically significant worse predictors for rectal cancer,whereas age and gender were not rel-evant.The multivariate Cox proportional hazard analysis revealed that HNF4αlow expression (RR=6.084, P=0.028)was independent prognostic markers for 3-year overall survival in the patients with rectal cancer. Conclusion HNF4αwas closely related to the tumorigenesis and progression of rectal cancer,which is an independent prognostic marker for rectal cancer,and which may be an effective target for the therapy of rectal cancer.

Research of hepatocyte nuclear factor 4α in digestive system tumors / 国际肿瘤学杂志

Hepatocyte nuclear factor 4α is a transcription factor of the nuclear hormone receptor superfamily and plays a very important role in the differentiation and development of the digestive system as well as the polarity regulation,which is considered to be a tumor suppressor gene.It also plays a very important role in digestive tumorigenesis,invasion and metastasis of hepatic carcinoma,colon cancer and gastric cancer,which is closely associated with epithelial-to-mesenchymal transition,the regulation of cell proliferation and wnt signaling pathway.HNF4α expression and its regulation mechanism in the digestive system tumors are now the research focus.

Effects of deoxyribonucleic acid methylation on the expression of hepatocyte nuclear factor-4α / 中华消化杂志

Objective To investigate the effect of deoxyribonucleic acid (DNA) methylation on the expression of hepatocyte nuclear factor-4α (HNF4c) and its role in the expression of HNF4α regulated by transforming growth factor-β1 (TGF-β1).Methods The expression of HNF4αP1 mRNA in six human hepatoma cell lines (HepG2,Huh-7,Hep3B,SMMC-7721,BEL-7405 and FOCUS),20 hepatic carcinoma specimens and corresponding adjacent tissues was detected by real-time reverse transcription polymerse chain reaction (real-time RT-PCR).The methylation status of the promoter region of HNF4αP1 in six human hepatoma cell lines was examined by bisulfite sequencing PCR (BSP).FOCUS cells were treated with 5-aza-2'-deoxycytidine (5-AZA-CdR) and then the methylation status of the promoter region of HNF4αP1 was examined by BSP.The expression of HNF4αP1 mRNA was detected by real-time RT-PCR.The six human hepatoma cell lines were treated with TGFβ1 and the expression of HNF4αP1 mRNA was detected by real-time RT-PCR.FOCUS cells were cotreated with 5-AZA-CdR,TGF-β1 and 5-AZA-CdR.The expression of HNF4αP1 mRNA was detected by real-time RT-PCR,and t test was performed for statistical analysis.Results Among 20 human hepatic carcinoma specimens and corresponding adjacent tissues,the expression of HNF4αP1 mRNA of 13 human hepatic carcinoma specimens was lower than that of corresponding adjacent tissues (t=2.350,P＜0.05).The relative quantity of the expression of HNF4αP1 mRNA was higher in Hep3B,HepG2 and Huh-7 cells,whereas that in SMMC-7721,BEL-7405 and FOCUS cells was lower.The methylation of the promoter region of HNF4αP1 in HepG2,Huh-7 and Hep3B was lower,but that in SMMC-7721,BEL-7405 and FOCUS was higher.Along with the increasing of the concentration of 5-AZA-CdR (0,0.1,1.0 and 2.5 μmol/L),the degree of the methylation of the promoter region of HNF4αP1 in FOCUS cells gradually decreased (61％,46％,32％ and 27％),and however the relative quantity of the expression of HNF4αP1 mRNA gradually increased ((9.661 ± 0.336)×10-7,(2.001±0.432)×10-6,(3.689±0.714)×10-6and (4.732±2.451)×10-6).After stimulated with TGF-β1,the relative quantity of the expression of HNF4αP1 mRNA was downregulated in HepG2,Huh-7 and Hep3B cells in which the methylation of the promoter region was low (t=12.994,8.441,and 9.032,all P＜0.01).There was no significant difference in the relative quantity of the expression of HNF4αP1 mRNA in SMMC-7721,BEL-7405 and FOCUS cells in which the methylation of the promoter region was high (all P ＞ 0.05).The relative quantity of the expression of HNF4αP1 mRNA in 5-AZA-CdR treated FOCUS cells ((4.972±0.035) × 10-6) was higher than that of control group ((1.411 ± 0.104) × 10-6) and the difference was statistically significant (t=13.212,P＜0.01).The relative quantity of the expression of HNF4αP1 mRNA in FOCUS cells co-treated with 5-AZA-CdR and TGF-β1 was lower than that in cells treated with 5-AZA-CdR alone and the difference was statistically significant ((1.181 ± 0.132) × 10-6 vs (4.972 ± 0.035) × 10-6,t=13.873,P＜0.01).Conclusions The expression of HNF4αP1 is down-regulated in hepatic carcinoma tissues.DNA methylation may regulate the expression of HNF4αP1 in hepatoma cells.The methylation of HNF4αP1 promoter region inhibits the regulating function of TGF-β1 in the expression of HNF4αP1.

Tissue-specific activation of mitogen-activated protein kinases for expression of transthyretin by phenylalanine and its metabolite, phenylpyruvic acid

Phenylketonuria is an autosomal recessive disorder caused by a deficiency of phenylalanine hydroxylase. Transthyretin has been implicated as an indicator of nutritional status in phenylketonuria patients. In this study, we report that phenylalanine and its metabolite, phenylpyruvic acid, affect MAPK, changing transthyretin expression in a cell- and tissue-specific manner. Treatment of HepG2 cells with phenylalanine or phenylpyruvic acid decreased transcription of the TTR gene and decreased the transcriptional activity of the TTR promoter site, which was partly mediated through HNF4alpha. Decreased levels of p38 MAPK were detected in the liver of phenylketonuria-affected mice compared with wild-type mice. In contrast, treatment with phenylalanine increased transthyretin expression and induced ERK1/2 activation in PC-12 cells; ERK1/2 activation was also elevated in the brainstem of phenylketonuria-affected mice. These findings may explain between-tissue differences in gene expression, including Ttr gene expression, in the phenylketonuria mouse model.