scholarly journals Hepatocyte Nuclear Factor 4 alpha (HNF4α) Activation is Essential for Termination of Liver Regeneration

2018 ◽  
Author(s):  
Ian Huck ◽  
Sumedha Gunewardena ◽  
Regina Espanol-Suner ◽  
Holger Willenbring ◽  
Udayan Apte
Keyword(s):  
Gene Expression ◽  
Liver Regeneration ◽  
Target Gene ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Hepatic Differentiation ◽  
Target Gene Expression ◽  
Protein Levels ◽  
Hepatocyte Nuclear Factor 4

AbstractHepatocyte Nuclear Factor 4 alpha (HNF4α) is critical for hepatic differentiation. Recent studies have highlighted its role in inhibition of hepatocyte proliferation and tumor suppression. However, the role of HNF4α in liver regeneration is not known. We hypothesized that hepatocytes modulate HNF4α activity when navigating between differentiated and proliferative states during liver regeneration. Western blot analysis revealed a rapid decline in nuclear and cytoplasmic HNF4α protein levels accompanied with decreased target gene expression within 1 hour after 2/3 partial hepatectomy (post-PH) in C57BL/6J mice. HNF4α protein expression did not recover to the pre-PH levels until day 3. Hepatocyte-specific deletion of HNF4α (HNF4α-KO) in mice resulted in 100% mortality post-PH despite increased proliferative marker expression throughout regeneration. Sustained loss of HNF4α target gene expression throughout regeneration indicated HNF4α-KO mice were unable to compensate for loss of HNF4α transcriptional activity. Deletion of HNF4α resulted in sustained proliferation accompanied by c-myc and cyclin D1 over expression and a complete deficiency of hepatocyte function after PH. Interestingly, overexpression of degradation-resistant HNF4α in hepatocytes did not prevent initiation of regeneration after PH. Finally, AAV8-mediated reexpression of HNF4α in hepatocytes of HNF4α-KO mice post-PH restored HNF4α protein levels, induced target gene expression and improved survival of HNF4α-KO mice post-PH. In conclusion, these data indicate that HNF4α reexpression following initial decrease is critical for hepatocytes to exit from cell cycle and resume function during the termination phase of liver regeneration. These results reveal the role of HNF4α in liver regeneration and have implications for therapy of liver failure.

Antagonism between apolipoprotein AI regulatory protein 1, Ear3/COUP-TF, and hepatocyte nuclear factor 4 modulates apolipoprotein CIII gene expression in liver and intestinal cells

1992 ◽  
Vol 12 (4) ◽  
pp. 1708-1718
Author(s):  
M Mietus-Snyder ◽  
F M Sladek ◽  
G S Ginsburg ◽  
C F Kuo ◽  
J A Ladias ◽  
...  
Keyword(s):  
Gene Expression ◽  
Regulatory Protein ◽  
Lipid Binding ◽  
Hepatic Tissue ◽  
Nuclear Factor ◽  
Apolipoprotein Ai ◽  
Hepatocyte Nuclear Factor ◽  
Apolipoprotein Ciii ◽  
Caco2 Cells ◽  
Hepatocyte Nuclear Factor 4

Apolipoprotein CIII (apoCIII), a lipid-binding protein involved in the transport of triglycerides and cholesterol in the plasma, is synthesized primarily in the liver and the intestine. A cis-acting regulatory element, C3P, located at -90 to -66 upstream from the apoCIII gene transcriptional start site (+1), is necessary for maximal expression of the apoCIII gene in human hepatoma (HepG2) and intestinal carcinoma (Caco2) cells. This report shows that three members of the steroid receptor superfamily of transcription factors, hepatocyte nuclear factor 4 (HNF-4), apolipoprotein AI regulatory protein 1 (ARP-1), and Ear3/COUP-TF, act at the C3P site. HNF-4 activates apoCIII gene expression in HepG2 and Caco2 cells, while ARP-1 and Ear3/COUP-TF repress its expression in the same cells. HNF-4 activation is abolished by increasing amounts of ARP-1 or Ear3/COUP-TF, and repression by ARP-1 or Ear3/COUP-TF is alleviated by increasing amounts of HNF-4. HNF-4 and ARP-1 bind with similar affinities to the C3P site, suggesting that their opposing transcriptional effects may be mediated by direct competition for DNA binding. HNF-4 and ARP-1 mRNAs are present within the same cells in the liver and intestine, and protein extracts from hepatic tissue, HepG2, and Caco2 cells contain significantly more HNF-4 than ARP-1 or Ear3/COUP-TF binding activities. These findings suggest that the transcription of the apoCIII gene in vivo is dependent, at least in part, upon the intracellular balance of these positive and negative regulatory factors.

scholarly journals Bile Acid Reduces the Secretion of Very Low Density Lipoprotein by Repressing Microsomal Triglyceride Transfer Protein Gene Expression Mediated by Hepatocyte Nuclear Factor-4

2004 ◽  
Vol 279 (44) ◽  
pp. 45685-45692 ◽  
Author(s):  
Hisako Hirokane ◽  
Mayuko Nakahara ◽  
Shizuko Tachibana ◽  
Makoto Shimizu ◽  
Ryuichiro Sato
Keyword(s):  
Gene Expression ◽  
Chenodeoxycholic Acid ◽  
Microsomal Triglyceride Transfer Protein ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Hep G2 ◽  
Hep G2 Cells ◽  
Apo B ◽  
Transfer Protein ◽  
Hepatocyte Nuclear Factor 4

Microsomal triglyceride transfer protein (MTP) is involved in the transfer of triglycerides, cholesterol esters, and phospholipids to newly synthesized apolipoprotein (apo) B. It is therefore essential for lipoprotein synthesis and secretion in the liver and the small intestine. Although several recent experiments have revealed the transcriptional regulation of the MTP gene, little has been revealed to date about hepatocyte nuclear factor-4 (HNF-4)-dependent regulation. We here report that the human MTP gene promoter contains a pair of functional responsive elements for HNF-4 and HNF-1, the latter of which is another target gene of HNF-4. Chromatin immunoprecipitation assays provide evidence that endogenous HNF-4 and HNF-1 can bind these elements in chromatin. In Hep G2 cells overexpression of either a dominant negative form of HNF-4 or small interfering RNAs (siRNAs) against HNF-4 dramatically reduces the activities of both the wild type and the HNF-4 site mutant MTP promoter. This suggests that HNF-4 regulates MTP gene expression either directly or indirectly through elevated HNF-1 levels. When Hep G2 cells were cultured with chenodeoxycholic acid (CDCA), a ligand for the farnesoid X receptor (FXR), mRNA levels for MTP and apo B were reduced because of increased expression of the factor small heterodimer partner (SHP), which factor suppresses HNF-4 activities. Chenodeoxycholic acid, but not a synthetic FXR ligand, attenuated expression of HNF-4, bringing about a further suppression of MTP gene expression. Over time the intracellular MTP protein levels and apo B secretion in the culture medium significantly declined. These results indicate that two nuclear receptors, HNF-4 and FXR, are closely involved in MTP gene expression, and the results provide evidence for a novel interaction between bile acids and lipoprotein metabolism.

scholarly journals Role of hepatocyte nuclear factor 4α in control of blood coagulation factor gene expression

2006 ◽  
Vol 84 (4) ◽  
pp. 345-345
Author(s):  
Yusuke Inoue ◽  
L. Luanne Peters ◽  
Sun Hee Yim ◽  
Junko Inoue ◽  
Frank J. Gonzalez
Keyword(s):  
Gene Expression ◽  
Blood Coagulation ◽  
Coagulation Factor ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Factor Gene ◽  
Hepatocyte Nuclear Factor 4Α

scholarly journals CDK6 kinase activity is required for thymocyte development

Blood ◽  
2011 ◽  
Vol 117 (23) ◽  
pp. 6120-6131 ◽  
Author(s):  
Miaofen G. Hu ◽  
Amit Deshpande ◽  
Nicolette Schlichting ◽  
Elisabeth A. Hinds ◽  
Changchuin Mao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Target Gene ◽  
Kinase Activity ◽  
Thymocyte Development ◽  
Hematopoietic Stem ◽  
Notch Target Gene ◽  
Target Gene Expression ◽  
Lymphoid Malignancies ◽  
Proliferation And Differentiation

Abstract Cyclin-dependent kinase-6 (CDK6) is required for early thymocyte development and tumorigenesis. To mechanistically dissect the role of CDK6 in thymocyte development, we generated and analyzed mutant knock-in mice and found that mice expressing a kinase-dead Cdk6 allele (Cdk6K43M) had a pronounced reduction in thymocytes and hematopoietic stem cells and progenitor cells (Lin−Sca-1+c-Kit+ [LSK]). In contrast, mice expressing the INK4-insensitive, hyperactive Cdk6R31C allele displayed excess proliferation in LSK and thymocytes. However, this is countered at least in part by increased apoptosis, which may limit progenitor and thymocyte expansion in the absence of other genetic events. Our mechanistic studies demonstrate that CDK6 kinase activity contributes to Notch signaling because inactive CDK6 kinase disrupts Notch-dependent survival, proliferation, and differentiation of LSK, with concomitant alteration of Notch target gene expression, such as massive up-regulation of CD25. Further, knockout of CD25 in Cdk6K43M mice rescued most defects observed in young mice. These results illustrate an important role for CDK6 kinase activity in thymocyte development that operates partially through modulating Notch target gene expression. This role of CDK6 as a downstream mediator of Notch identifies CDK6 kinase activity as a potential therapeutic target in human lymphoid malignancies.

scholarly journals Antagonism between apolipoprotein AI regulatory protein 1, Ear3/COUP-TF, and hepatocyte nuclear factor 4 modulates apolipoprotein CIII gene expression in liver and intestinal cells.

1992 ◽  
Vol 12 (4) ◽  
pp. 1708-1718 ◽  
Author(s):  
M Mietus-Snyder ◽  
F M Sladek ◽  
G S Ginsburg ◽  
C F Kuo ◽  
J A Ladias ◽  
...  
Keyword(s):  
Gene Expression ◽  
Regulatory Protein ◽  
Lipid Binding ◽  
Hepatic Tissue ◽  
Nuclear Factor ◽  
Apolipoprotein Ai ◽  
Hepatocyte Nuclear Factor ◽  
Apolipoprotein Ciii ◽  
Caco2 Cells ◽  
Hepatocyte Nuclear Factor 4

Apolipoprotein CIII (apoCIII), a lipid-binding protein involved in the transport of triglycerides and cholesterol in the plasma, is synthesized primarily in the liver and the intestine. A cis-acting regulatory element, C3P, located at -90 to -66 upstream from the apoCIII gene transcriptional start site (+1), is necessary for maximal expression of the apoCIII gene in human hepatoma (HepG2) and intestinal carcinoma (Caco2) cells. This report shows that three members of the steroid receptor superfamily of transcription factors, hepatocyte nuclear factor 4 (HNF-4), apolipoprotein AI regulatory protein 1 (ARP-1), and Ear3/COUP-TF, act at the C3P site. HNF-4 activates apoCIII gene expression in HepG2 and Caco2 cells, while ARP-1 and Ear3/COUP-TF repress its expression in the same cells. HNF-4 activation is abolished by increasing amounts of ARP-1 or Ear3/COUP-TF, and repression by ARP-1 or Ear3/COUP-TF is alleviated by increasing amounts of HNF-4. HNF-4 and ARP-1 bind with similar affinities to the C3P site, suggesting that their opposing transcriptional effects may be mediated by direct competition for DNA binding. HNF-4 and ARP-1 mRNAs are present within the same cells in the liver and intestine, and protein extracts from hepatic tissue, HepG2, and Caco2 cells contain significantly more HNF-4 than ARP-1 or Ear3/COUP-TF binding activities. These findings suggest that the transcription of the apoCIII gene in vivo is dependent, at least in part, upon the intracellular balance of these positive and negative regulatory factors.

scholarly journals Hepatocyte-specific deletion of hepatocyte nuclear factor-4α in adult mice results in increased hepatocyte proliferation

2013 ◽  
Vol 304 (1) ◽  
pp. G26-G37 ◽  
Author(s):  
Chad Walesky ◽  
Sumedha Gunewardena ◽  
Ernest F. Terwilliger ◽  
Genea Edwards ◽  
Prachi Borude ◽  
...  
Keyword(s):  
Gene Expression ◽  
Target Genes ◽  
Viral Vector ◽  
Hepatocyte Proliferation ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Hepatocyte Differentiation ◽  
Hepatic Differentiation ◽  
Hepatocyte Nuclear Factor 4Α ◽  
Specific Deletion

Hepatocyte nuclear factor-4α (HNF4α) is known as the master regulator of hepatocyte differentiation. Recent studies indicate that HNF4α may inhibit hepatocyte proliferation via mechanisms that have yet to be identified. Using a HNF4α knockdown mouse model based on delivery of inducible Cre recombinase via an adeno-associated virus 8 viral vector, we investigated the role of HNF4α in the regulation of hepatocyte proliferation. Hepatocyte-specific deletion of HNF4α resulted in increased hepatocyte proliferation. Global gene expression analysis showed that a majority of the downregulated genes were previously known HNF4α target genes involved in hepatic differentiation. Interestingly, ≥500 upregulated genes were associated with cell proliferation and cancer. Furthermore, we identified potential negative target genes of HNF4α, many of which are involved in the stimulation of proliferation. Using chromatin immunoprecipitation analysis, we confirmed binding of HNF4α at three of these genes. Furthermore, overexpression of HNF4α in mouse hepatocellular carcinoma cells resulted in a decrease in promitogenic gene expression and cell cycle arrest. Taken together, these data indicate that, apart from its role in hepatocyte differentiation, HNF4α actively inhibits hepatocyte proliferation by repression of specific promitogenic genes.

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