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Yamaguchi N, Miyamoto S, Ogura Y, Goda T, Suruga K. Hepatocyte nuclear factor-4alpha regulates human cellular retinol-binding protein type II gene expression in intestinal cells. Am J Physiol Gastrointest Liver Physiol 2009; 296:G524-33. [PMID: 19147806 DOI: 10.1152/ajpgi.90469.2008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cellular retinol-binding protein type II (CRBPII) is abundantly expressed in the small intestinal enterocytes of many vertebrates and plays important physiological roles in intestinal absorption, transport, and metabolism of vitamin A. In the present study, we investigated regulation of human CRBPII gene expression using human intestinal Caco-2 BBe cells. We found that the human CRBPII gene contained a direct repeat 1 (DR-1)-like nuclear receptor response element in the proximal promoter region and that endogenous hepatocyte nuclear factor-4alpha (HNF-4alpha) was a major transcription factor binding to the DR-1-like element. Cotransfection of HNF-4alpha expression vector transactivated the human CRBPII gene promoter activity, whereas mutation of the DR-1-like element abolished the promoter activity. Stably transfected Caco-2 BBe cells overexpressing HNF-4alpha significantly increased endogenous CRBPII gene expression and retinyl ester synthesis. Reduction of HNF-4alpha protein levels by HNF-4alpha small interference RNA decreased CRBPII gene expression. Caco-2 BBe cells treated with phorbol 12-myristate 13-acetate, a protein kinase C activator, decreased nuclear HNF-4alpha protein level and binding activity to the human CRBPII gene DR-1-like element, as well as CRBPII gene expression. Moreover, nuclear HNF-4alpha protein levels, HNF-4alpha protein binding to human CRBPII DR-1-like elements, and CRBPII gene expression level were coordinately increased during Caco-2 BBe cell differentiation. These results suggest that HNF-4alpha is an important transcriptional factor that regulates human CRBPII gene expression and provide the possibility for a novel function of HNF-4alpha in the regulation of human intestinal vitamin A absorption and metabolism.
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Affiliation(s)
- Noriaki Yamaguchi
- Graduate School of Human Health Sciences, University of Nagasaki, 1-1-1 Manabino, Nagayo-cho, Nishisonogi-gun, Nagasaki 851-2195, Japan
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Takegoshi S, Jiang S, Ohashi R, Savchenko AS, Iwanari H, Tanaka T, Hasegawa G, Hamakubo T, Kodama T, Naito M. Protein expression of nuclear receptors in human and murine tissues. Pathol Int 2009; 59:61-72. [DOI: 10.1111/j.1440-1827.2008.02330.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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53
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Sugai M, Umezu H, Yamamoto T, Jiang S, Iwanari H, Tanaka T, Hamakubo T, Kodama T, Naito M. Expression of hepatocyte nuclear factor 4 alpha in primary ovarian mucinous tumors. Pathol Int 2008; 58:681-6. [PMID: 18844932 DOI: 10.1111/j.1440-1827.2008.02293.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hepatocyte nuclear factor 4 alpha (HNF4 alpha) is a member of the nuclear receptor superfamily and is expressed in several endodermal tissues. The aim of the present study was to examine the expression of HNF4 alpha on ovarian epithelial tumors with immunocytochemistry and immunohistochemistry using mAbs recognizing P1 and P2 promoter-driven HNF4 alpha. Ovarian mucinous adenoma, mucinous tumors of borderline malignancy, and mucinous adenocarcinoma had positive nuclear staining for HNF4 alpha (41/45, 91%). One-third (34%) of mucinous tumors had P1-positive staining and most had P1/P2-positive staining (93%). MUC2- and MUC5AC-positive staining was observed in 34% and 95% of mucinous tumors, respectively. The histological subtype of these mucinous tumors was not correlated with HNF4 alpha expression. On cytology it was found that cancer cells in the ascites from ovarian mucinous adenocarcinomas were HNF4 alpha positive, but tumor cells in ascites from other types of ovarian carcinomas were negative for HNF4 alpha. Thus, HNF4 alpha is demonstrated to be a useful marker for histological and cytological diagnosis of ovarian mucinous tumors.
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Affiliation(s)
- Mika Sugai
- Division of Cellular and Molecular Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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Lazarevich NL, Fleishman DI. Tissue-specific transcription factors in progression of epithelial tumors. BIOCHEMISTRY (MOSCOW) 2008; 73:573-91. [PMID: 18605982 DOI: 10.1134/s0006297908050106] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Dedifferentiation and epithelial-mesenchymal transition are important steps in epithelial tumor progression. A central role in the control of functional and morphological properties of different cell types is attributed to tissue-specific transcription factors which form regulatory cascades that define specification and differentiation of epithelial cells during embryonic development. The main principles of the action of such regulatory systems are reviewed on an example of a network of hepatocyte nuclear factors (HNFs) which play a key role in establishment and maintenance of hepatocytes--the major functional type of liver cells. HNFs, described as proteins binding to promoters of most hepatospecific genes, not only control expression of functional liver genes, but are also involved in regulation of proliferation, morphogenesis, and detoxification processes. One of the central components of the hepatospecific regulatory network is nuclear receptor HNF4alpha. Derangement of the expression of this gene is associated with progression of rodent and human hepatocellular carcinomas (HCCs) and contributes to increase of proliferation, loss of epithelial morphology, and dedifferentiation. Dysfunction of HNF4alpha during HCC progression can be either caused by structural changes of this gene or occurs due to modification of up-stream regulatory signaling pathways. Investigations preformed on a model system of the mouse one-step HCC progression have shown that the restoration of HNF4alpha function in dedifferentiated cells causes partial reversion of malignant phenotype both in vitro and in vivo. Derangement of HNFs function was also described in other tumors of epithelial origin. We suppose that tissue-specific factors that underlie the key steps in differentiation programs of certain tissues and are able to receive or modulate signals from the cell environment might be considered as promising candidates for the role of tumor suppressors in the tissue types where they normally play the most significant role.
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Affiliation(s)
- N L Lazarevich
- Institute of Carcinogenesis, Blokhin Russian Cancer Research Center, Russian Academy of Medical Sciences, Moscow 115478, Russia.
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Kishimoto T, Yano T, Hiroshima K, Inayama Y, Kawachi K, Nakatani Y. A case of *-fetoprotein-producing pulmonary carcinoma with restricted expression of hepatocyte nuclear factor-4* in hepatoid foci: a case report with studies of previous cases. Hum Pathol 2008; 39:1115-20. [PMID: 18570977 DOI: 10.1016/j.humpath.2007.12.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 12/11/2007] [Accepted: 12/26/2007] [Indexed: 12/11/2022]
Abstract
We report a case of *-fetoprotein (AFP)-producing pulmonary carcinoma with studies for messenger RNA (mRNA) expression of hepatocyte nuclear factor (HNF)-4*, which is a transcription factor that is highly expressed in the process of liver development. The patient was a 64-year-old man with a pulmonary tumor in his left lower lobe. Serum AFP was 673 ng/mL. The microscopic analysis of the surgical specimen revealed a large cell neuroendocrine carcinoma with occasional hepatoid foci. The competitive reverse transcriptase polymerase chain reaction analysis revealed that HNF-4* mRNA was expressed on the order of 10(2)- to 10(3)-fold more abundantly than control pulmonary carcinomas and normal lung tissues. In addition, AFP and HNF-4* expression was restricted in hepatoid foci. Two previously reported cases of AFP-producing pulmonary carcinoma were also positive, whereas all 18 control pulmonary carcinomas were negative for HNF-4*. These findings suggest that aberrant expression of HNF-4* is implicated in the emergence or maintenance of hepatoid foci in AFP-producing pulmonary carcinomas.
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Affiliation(s)
- Takashi Kishimoto
- Department of Molecular Pathology (E3), Chiba University Graduate School of Medicine, Chiba 260-8670, Japan.
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57
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Ahn SH, Shah YM, Inoue J, Morimura K, Kim I, Yim S, Lambert G, Kurotani R, Nagashima K, Gonzalez FJ, Inoue Y. Hepatocyte nuclear factor 4alpha in the intestinal epithelial cells protects against inflammatory bowel disease. Inflamm Bowel Dis 2008; 14:908-20. [PMID: 18338782 PMCID: PMC2435391 DOI: 10.1002/ibd.20413] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Hepatocyte nuclear factor 4alpha (HNF4alpha; NR2A1) is an orphan member of the nuclear receptor superfamily expressed in liver and intestine. While HNF4alpha expression is critical for liver function, its role in the gut and in the pathogenesis of inflammatory bowel disease (IBD) is unknown. METHODS Human intestinal biopsies from control and IBD patients were examined for expression of mRNAs encoding HNF4alpha and other nuclear receptors. An intestine-specific HNF4alpha null mouse line (Hnf4alpha(DeltaIEpC)) was generated using an Hnf4alpha-floxed allele and villin-Cre transgene. These mice and their control floxed counterparts (Hnf4alpha(F/F)), were subjected to a dextran sulfate sodium (DSS)-induced IBD colitis protocol and their clinical symptoms and gene expression patterns determined. RESULTS In human intestinal biopsies, HNF4alpha was significantly decreased in intestinal tissues from Crohn's disease and ulcerative colitis patients. HNF4alpha expression was also suppressed in the intestine of DSS-treated mice. In Hnf4alpha(DeltaIEpC) mice, disruption of HNF4alpha expression was observed in the epithelial cells throughout the intestine. In the DSS-induced colitis model Hnf4alpha(DeltaIEpC) mice showed markedly more severe changes in clinical symptoms and pathologies associated with IBD including loss of body weight, colon length, and histological morphology as compared with Hnf4alpha(F/F) mice. Furthermore, the Hnf4alpha(DeltaIEpC) mice demonstrate a significant alteration of mucin-associated genes and increased intestinal permeability, which may play an important role in the increased susceptibility to acute colitis following an inflammatory insult. CONCLUSIONS While HNF4alpha does not have a major role in normal function of the intestine, it protects the gut against DSS-induced colitis.
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Affiliation(s)
- Sung-Hoon Ahn
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Yatrik M. Shah
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Junko Inoue
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Keiichiro Morimura
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
- Department of Pathology, Osaka City University Medical School, Osaka 545-8585, Japan
| | - Insook Kim
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - SunHee Yim
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Gilles Lambert
- Universite de Nantes, Inserm U539, CHU Hotel-Dieu, Nantes 44035, France and The Heart Research Institute, Camperdown, NSW 2050, Australia
| | - Reiko Kurotani
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
- Cardiovascular Research Institute, Yokohama City University, Yokohama 236-0004, Japan
| | - Kunio Nagashima
- Image Analysis Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702
| | - Frank J. Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Yusuke Inoue
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
- Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University, Kiryu, Gunma 376-8515 Japan
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Gonzalez FJ. Regulation of hepatocyte nuclear factor 4 alpha-mediated transcription. Drug Metab Pharmacokinet 2008; 23:2-7. [PMID: 18305369 DOI: 10.2133/dmpk.23.2] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Hepatocyte nuclear factor 4alpha (HNF4alpha, NR2A1) is required for development of the liver and for controlling the expression of many genes specifically expressed in the liver and associated with a number of critical metabolic pathways. Among the genes regulated by HNF4alpha are the xenobiotic-metabolizing cytochromes P450, UDP-glucuronosyltransferases and sulfotransferases thus making this transcription factor critical in the control of drug metabolism. HNF4alpha, a member of the nuclear receptor superfamily, binds as a homodimer to direct repeat elements upstream of target genes. However, in contrast to many other nuclear receptors, there is no convincing evidence that HNF4alpha is activated by exogenous ligands, at least in the classic mechanism used by other steroid and metabolic nuclear receptors. X-ray crystallographic studies revealed that HNF4alpha has a fatty acid embedded in its putative ligand binding site that may not be easily released or displaced by exogenous ligands. HNF4alpha, as a general rule, controls constitutive expression of many hepatic genes but under certain circumstances can be subjected to regulation by differential co-activator recruitment, by phosphorylation and by interaction with other nuclear receptors. The ability of HNF4alpha to be regulated offers hope that it could be a drug target.
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Affiliation(s)
- Frank J Gonzalez
- Laboratory of Metabolism, National Cancer Institute, National Instituted of Health, Bethesda, Maryland 20892, USA.
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59
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HNF4alpha is a crucial modulator of the cholesterol-dependent regulation of NPC1L1. Pharm Res 2007; 25:1134-41. [PMID: 18080173 DOI: 10.1007/s11095-007-9496-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 11/06/2007] [Indexed: 02/06/2023]
Abstract
PURPOSE Niemann-Pick C1-like 1 (NPC1L1) has been identified as a target of ezetimibe and found to be responsible for intestinal cholesterol absorption. Although, it was recently demonstrated that sterol responsive element binding protein 2 (SREBP2) is responsible for the cholesterol-dependent down-regulation of NPC1L1, the molecular mechanism of NPC1L1 expression is not fully understood. In the present study, we examined the involvement of hepatocyte nuclear factor 4alpha (HNF4alpha), a key modulator of lipid metabolism, in the transcriptional regulation of human NPC1L1 gene. METHODS Reporter gene assays and EMSAs were performed using human NPC1L1 promoter constructs and the effect of siHNF4alpha was examined. RESULTS Transfection of SREBP2 induced the transcriptional activities of NPC1L1 and additional transfection of HNF4alpha results in a marked stimulation of the activities. Studies with deletion mutants indicated that important elements are located within 264 nt upstream in the human NPC1L1 promoter. In addition, studies with mutations in putative binding sites of HNF4alpha indicated the existence of binding sites in -209 to -197 and -52 to -40. Moreover, HNF4alpha knockdown resulted in the reduced expression and regulation by cholesterol. CONCLUSIONS It is concluded that HNF4alpha plays a crucial role in the expression and regulation of human NPC1L1 gene.
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Saji T, Kikuchi R, Kusuhara H, Kim I, Gonzalez FJ, Sugiyama Y. Transcriptional regulation of human and mouse organic anion transporter 1 by hepatocyte nuclear factor 1 alpha/beta. J Pharmacol Exp Ther 2007; 324:784-90. [PMID: 18029548 DOI: 10.1124/jpet.107.128249] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Organic anion transporter 1 (OAT1/SLC22A6) is predominantly expressed in the proximal tubules of the kidney. Cumulative studies have shown its critical role in the tubular secretion of a variety of organic anions, including several clinically important drugs. In addition, OAT1 is also involved in the pharmacological effect of diuretics and the nephrotoxicity of antiviral drugs. In contrast to these functional characterizations, the regulatory mechanism of OAT1 expression is poorly understood. It was recently demonstrated that the expression of Oat1 was markedly reduced in the kidneys of hepatocyte nuclear factor 1alpha (Hnf1alpha)-null mice. However, in vitro evidence for the involvement of HNF1alpha and further analyses are required to illustrate the transcriptional regulation of OAT1 genes in more detail. Computational analysis of the potential transcription factor binding sites revealed that the HNF1-motif was conserved in the proximal-promoter region of human and mouse OAT1 genes. The mRNA expression of mouse organic anion transporter 1 was drastically reduced in Hnf1alpha-null mice compared with that in wild-type mice, which was consistent with a previous report (Maher et al., 2006). Forced expression of HNF1alpha alone or both HNF1alpha and HNF1beta enhanced the activity of human and mouse OAT1 promoters in the transactivation assays, whereas HNF1beta alone was not active. Mutations in the HNF1-motif significantly reduced this transactivation. Direct binding of HNF1alpha/HNF1alpha homodimer and HNF1alpha/HNF1beta heterodimer to the HNF1-motif found in the human OAT1 promoter was demonstrated by electrophoretic mobility shift assays. These results provide convincing evidence for the involvement of HNF1alpha/beta in the constitutive expression of human and mouse OAT1 in the kidney.
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Affiliation(s)
- Takami Saji
- Department of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, USA
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Goodyer CG, Rhani Z, Zheng H. Expression of the hepatic specific V1 messenger ribonucleic acid of the human growth hormone receptor gene is regulated by hepatic nuclear factor (HNF)-4alpha2 and HNF-4alpha8. Mol Endocrinol 2007; 22:485-500. [PMID: 17991764 DOI: 10.1210/me.2007-0387] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Human (h) GH plays an essential role in growth and metabolism, and its effectiveness is modulated by the availability of its specific receptor [hGH receptor (hGHR)] on target cells. The hGHR gene has a complex 5'-regulatory region containing multiple first exons. Seven are clustered within two small regions: V2,V3,V9 (module A) and V1,V4,V7,V8 (module B). Module A-derived mRNAs are ubiquitously expressed whereas those from module B are only found in postnatal liver, suggesting developmental- and liver-specific regulation of module B hGHR gene expression. To characterize the elements regulating module B activity, we studied a 1.8-kb promoter of the highest expressing exon in liver, V1. This promoter was repressed in transfection assays; however, either 5'- or 3'-deletions relieved this, suggesting the presence of multiple negative regulatory elements. Six putative hepatic nuclear factor 4 (HNF-4) response elements were identified. We determined that HNF-4alpha is developmentally regulated in the human liver: HNF-4alpha2 and HNF-4alpha8 are expressed in fetal hepatocytes but only HNF-4alpha2 is expressed in postnatal liver. Transient transfection assays demonstrated that HNF-4alpha2 and HNF-4alpha8 have a similar dual effect on V1 transcription: activation via site 1 in the proximal promoter and repression through site 6, approximately 1.7 kb upstream. EMSA/electrophoretic mobility supershift assays and chromatin immunoprecipitation analyses confirmed these two sites are bound by HNF-4alpha. Based on these data, we speculate there are multiple regions working together to repress the expression of V1 hGHR transcripts in tissues other than the normal postnatal liver, and that HNF-4alpha is a good candidate for regulating V1 hGHR expression in the human hepatocyte.
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Affiliation(s)
- Cynthia Gates Goodyer
- McGill University Health Centre-Montreal Children's Hospital Research Institute, 4060 St Catherine West, Montreal, Quebec, Canada.
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Kojima K, Kishimoto T, Nagai Y, Tanizawa T, Nakatani Y, Miyazaki M, Ishikura H. The expression of hepatocyte nuclear factor-4alpha, a developmental regulator of visceral endoderm, correlates with the intestinal phenotype of gastric adenocarcinomas. Pathology 2007; 38:548-54. [PMID: 17393984 DOI: 10.1080/00313020601024011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
AIMS Hepatocyte nuclear factor (HNF)-4alpha is a developmental regulator of the visceral endoderm, which is expressed in the embryonic gut and later in the adult intestine and colon. However, adult gastric mucosa does not express HNF-4alpha. We investigated the possible involvement of HNF-4alpha in intestinal metaplasia and the intestinalisation of gastric adenocarcinomas. METHODS Thirty-five cases of adenocarcinomas and 46 cases of adjacent non-neoplastic mucosa with (22 lesions) or without (24 lesions) intestinal metaplasia were immunostained for HNF-4alpha. The gastric or the intestinal phenotype was also examined using immunohistochemistry for MUC5AC, MUC2, CD10, and gastric-type mucin (GTM). Adenocarcinomas were classified into the gastric type (G-type, 42.9%), the mixed gastric and intestinal type (GI-type, 31.4%), and the intestinal type (I-type, 25.7%). RESULTS The HNF-4alpha expression was exclusively seen in glandular cells with intestinal metaplasia, which was correlated with MUC2 expression (p<0.05) and inversely correlated with MUC5AC expression (p<0.05). All adenocarcinomas more or less expressed HNF-4alpha, with an intense expression being seen in the I-type (p<0.01) and in well-differentiated adenocarcinomas (p<0.03). CONCLUSIONS HNF-4alpha expression is associated with the intestinal phenotype of non-neoplastic and neoplastic gastric glandular cells, suggesting a possible involvement in the establishment and/or maintenance of the intestinal phenotype of the gastric mucosa and adenocarcinomas.
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Affiliation(s)
- Kazuhiro Kojima
- Department of Molecular Pathology, Chiba University Graduate School of Medicine, Chiba, Japan
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63
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Sumi K, Tanaka T, Uchida A, Magoori K, Urashima Y, Ohashi R, Ohguchi H, Okamura M, Kudo H, Daigo K, Maejima T, Kojima N, Sakakibara I, Jiang S, Hasegawa G, Kim I, Osborne TF, Naito M, Gonzalez FJ, Hamakubo T, Kodama T, Sakai J. Cooperative interaction between hepatocyte nuclear factor 4 alpha and GATA transcription factors regulates ATP-binding cassette sterol transporters ABCG5 and ABCG8. Mol Cell Biol 2007; 27:4248-60. [PMID: 17403900 PMCID: PMC1900057 DOI: 10.1128/mcb.01894-06] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cholesterol homeostasis is maintained by coordinate regulation of cholesterol synthesis and its conversion to bile acids in the liver. The excretion of cholesterol from liver and intestine is regulated by ATP-binding cassette half-transporters ABCG5 and ABCG8. The genes for these two proteins are closely linked and divergently transcribed from a common intergenic promoter region. Here, we identified a binding site for hepatocyte nuclear factor 4alpha (HNF4alpha) in the ABCG5/ABCG8 intergenic promoter, through which HNF4alpha strongly activated the expression of a reporter gene in both directions. The HNF4alpha-responsive element is flanked by two conserved GATA boxes that were also required for stimulation by HNF4alpha. GATA4 and GATA6 bind to the GATA boxes, coexpression of GATA4 and HNF4alpha leads to a striking synergistic activation of both the ABCG5 and the ABCG8 promoters, and binding sites for HNF4alpha and GATA were essential for maximal synergism. We also show that HNF4alpha, GATA4, and GATA6 colocalize in the nuclei of HepG2 cells and that a physical interaction between HNF4alpha and GATA4 is critical for the synergistic response. This is the first demonstration that HNF4alpha acts synergistically with GATA factors to activate gene expression in a bidirectional fashion.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily G, Member 5
- ATP Binding Cassette Transporter, Subfamily G, Member 8
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Adenoviridae/genetics
- Amino Acid Motifs
- Amino Acid Sequence
- Base Sequence
- Binding Sites
- Carcinoma, Hepatocellular/metabolism
- Carcinoma, Hepatocellular/pathology
- Cell Line
- Cell Line, Tumor
- Consensus Sequence
- Conserved Sequence
- GATA4 Transcription Factor/genetics
- GATA4 Transcription Factor/metabolism
- GATA6 Transcription Factor/genetics
- GATA6 Transcription Factor/metabolism
- Gene Deletion
- Genes, Reporter
- Hepatocyte Nuclear Factor 4/chemistry
- Hepatocyte Nuclear Factor 4/metabolism
- Humans
- Lipoproteins/genetics
- Lipoproteins/metabolism
- Liver Neoplasms/metabolism
- Liver Neoplasms/pathology
- Luciferases/metabolism
- Molecular Sequence Data
- Oligonucleotide Array Sequence Analysis
- Promoter Regions, Genetic
- Protein Binding
- Protein Structure, Tertiary
- RNA Interference
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- Koichi Sumi
- Laboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo, Japan
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Ogasawara K, Terada T, Asaka JI, Katsura T, Inui KI. Hepatocyte nuclear factor-4{alpha} regulates the human organic anion transporter 1 gene in the kidney. Am J Physiol Renal Physiol 2007; 292:F1819-26. [PMID: 17344191 DOI: 10.1152/ajprenal.00017.2007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Human organic anion transporter 1 (OAT1, SLC22A6), which is localized to the basolateral membranes of renal tubular epithelial cells, plays a critical role in the excretion of anionic compounds. OAT1 is regulated by various pathophysiological conditions, but little is known about the molecular mechanisms regulating the expression of OAT1. In the present study, we investigated the transcriptional regulation of OAT1 and found that hepatocyte nuclear factor (HNF)-4alpha markedly transactivated the OAT1 promoter. A deletion analysis of the OAT1 promoter suggested that the regions spanning -1191 to -700 base pairs (bp) and -140 to -79 bp were essential for the transactivation by HNF-4alpha. These regions contained a direct repeat separated by two nucleotides (DR-2), which is one of the consensus sequences binding to HNF-4alpha, and an inverted repeat separated by eight nucleotides (IR-8), which was recently identified as a novel element for HNF-4alpha, respectively. An electrophoretic mobility shift assay showed that HNF-4alpha bound to DR-2 and IR-8 under the conditions of HNF-4alpha overexpression. Furthermore, under normal conditions, HNF-4alpha bound to IR-8, and a mutation in IR-8 markedly reduced the OAT1 promoter activity, indicating that HNF-4alpha regulates the basal transcription of OAT1 via IR-8. This paper reports the first characterization of the human OAT1 promoter and the first gene in the kidney whose promoter activity is regulated by HNF-4alpha.
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Affiliation(s)
- Ken Ogasawara
- Department of Pharmacy, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Kyoto, Japan
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65
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Harries LW. Alternate mRNA processing of the hepatocyte nuclear factor genes and its role in monogenic diabetes. Expert Rev Endocrinol Metab 2006; 1:715-726. [PMID: 30754156 DOI: 10.1586/17446651.1.6.715] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Variation in mRNA processing has the capacity to exert fine control over gene expression in most cell types. The hepatic nuclear factor genes, like approximately 74% of the genome, produce multiple transcripts. Hepatic nuclear factor isoforms exhibit both spatial and temporal variation in expression. In this review, the known isoforms of the hepatocyte nuclear factor-1α, hepatocyte nuclear factor-1β and hepatocyte nuclear factor-4α genes are described and their properties are compared. Finally, data are discussed regarding the influence of hepatocyte nuclear factor-1α alternate mRNA processing on the clinical phenotype of maturity-onset diabetes of the young.
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Affiliation(s)
- Lorna W Harries
- a RCUK Diabetes and Metabolism Academic Fellow, Institute of Biomedical and Clinical Sciences, Peninsula Medical School, Barrack Road, Exeter, EX2 5DW, UK.
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66
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Tanaka T, Jiang S, Hotta H, Takano K, Iwanari H, Sumi K, Daigo K, Ohashi R, Sugai M, Ikegame C, Umezu H, Hirayama Y, Midorikawa Y, Hippo Y, Watanabe A, Uchiyama Y, Hasegawa G, Reid P, Aburatani H, Hamakubo T, Sakai J, Naito M, Kodama T. Dysregulated expression of P1 and P2 promoter-driven hepatocyte nuclear factor-4α in the pathogenesis of human cancer. J Pathol 2006; 208:662-72. [PMID: 16400631 DOI: 10.1002/path.1928] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hepatocyte nuclear factor-4alpha (HNF4alpha) exists in multiple isoforms that are generated by alternative promoter (P1 and P2) usage and splicing. Here we establish monoclonal antibodies (mAbs) for detecting P1 and P2 promoter-driven HNF4alpha, and evaluate their expression in normal adult human tissues and surgically resected carcinomas of different origins. Using immunohistochemical analysis, we demonstrate that, while P1 promoter-driven HNF4alpha is expressed in hepatocytes, small intestine, colon, kidney and epididymis, P2 promoter-driven HNF4alpha is expressed in bile duct, pancreas, stomach, small intestine, colon and epididymis. Altered expression patterns of P1 and P2 promoter-driven HNF4alpha were observed in gastric, hepatocellular and colorectal carcinomas. HNF4alpha was expressed in lung metastases from renal cell, hepatocellular and colorectal carcinoma but was not observed in lung tumours. The P1 and P2 promoter-driven HNF4alpha expression pattern of tumour metastases correlated with the primary site of origin. P1 promoter-driven HNF4alpha was also found in intestinal metaplasia of the stomach. These data provide evidence for the tissue distribution of P1 and P2 promoter-driven HNF4alpha at the protein level and suggest that HNF4alpha may be a novel diagnostic marker for metastases of unknown primary. We propose that the dysregulation of alternative promoter usage of HNF4alpha is associated with the pathogenesis of certain cancers.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- Antibody Specificity
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/immunology
- Biomarkers, Tumor/metabolism
- Cell Transformation, Neoplastic/genetics
- Female
- Gene Expression Regulation, Neoplastic
- Hepatocyte Nuclear Factor 4/genetics
- Hepatocyte Nuclear Factor 4/immunology
- Hepatocyte Nuclear Factor 4/metabolism
- Humans
- Lung Neoplasms/metabolism
- Lung Neoplasms/secondary
- Male
- Neoplasm Proteins/genetics
- Neoplasm Proteins/immunology
- Neoplasm Proteins/metabolism
- Neoplasms/genetics
- Neoplasms/metabolism
- Precancerous Conditions/metabolism
- Promoter Regions, Genetic
- RNA, Messenger/genetics
- RNA, Neoplasm/genetics
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Stomach Neoplasms/metabolism
- Tissue Distribution
- Tumor Cells, Cultured
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Affiliation(s)
- T Tanaka
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
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67
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Abstract
Nuclear receptors are transcription factors that are essential in embryonic development, maintenance of differentiated cellular phenotypes, metabolism, and apoptosis. Dysfunction of nuclear receptor signaling leads to a wide spectra of proliferative, reproductive, and metabolic diseases, including cancers, infertility, obesity, and diabetes. In addition, many proteins have been identified as coregulators which can be recruited by DNA-binding nuclear receptors to affect transcriptional regulation. The cellular level of coregulators is crucial for nuclear receptor-mediated transcription and many coregulators have been shown to be targets for diverse intracellular signaling pathways and posttranslational modifications. This review provides a general overview of the roles and mechanism of action of nuclear receptors and their coregulators. Since progression of renal diseases is almost always associated with inflammatory processes and/or involve metabolic disorders of lipid and glucose, cell proliferation, hypertrophy, apoptosis, and hypertension, the importance of nuclear receptors and their coregulators in these contexts will be addressed.
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Affiliation(s)
- Xiong Z Ruan
- Centre for Nephrology, Royal Free and University College Medical School, University College London, Royal Free Campus, Rowland Hill Street, London, United Kingdom.
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68
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Lucas B, Grigo K, Erdmann S, Lausen J, Klein-Hitpass L, Ryffel GU. HNF4alpha reduces proliferation of kidney cells and affects genes deregulated in renal cell carcinoma. Oncogene 2005; 24:6418-31. [PMID: 16007190 DOI: 10.1038/sj.onc.1208794] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Hepatocyte nuclear factor 4alpha (HNF4alpha) is a tissue-specific transcription factor known to regulate a large number of genes in hepatocytes and pancreatic beta cells. Although HNF4alpha is highly expressed in some sections of the kidney, little is known about its role in this organ and about HNF4alpha-regulated genes in the kidney cells. The abundance and activity of HNF4alpha are frequently reduced in renal cell carcinoma (RCC) indicating some tumor suppressing function of HNF4alpha in renal cells. To determine the potential role of HNF4alpha in RCC, we used Flp recombinase-mediated gene integration to generate human embryonic kidney cells (HEK293) that conditionally express wild-type or mutated HNF4alpha. Expression of wild-type HNF4alpha but not of the mutants led to reduction of proliferation and alterations of cell morphology. These effects were reversible and induced at physiological concentrations of HNF4alpha. Using gene expression profiling by microarrays, we determined genes regulated by HNF4alpha. Interestingly, many of the genes regulated by HNF4alpha have been shown to be deregulated in RCC microarray studies. These genes (ACY1, WT1, SELENBP1, COBL, EFHD1, AGXT2L1, ALDH5A1, THEM2, ABCB1, FLJ14146, CSPG2, TRIM9 and HEY1) are good candidates for genes whose activity is changed upon the decrease of HNF4alpha in RCC.
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Affiliation(s)
- Belén Lucas
- Institut für Zellbiologie (Tumorforschung), Universitätsklinikum Essen, D-45122 Essen, Germany
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69
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Tochigi N, Kishimoto T, Suyama T, Nagai Y, Nikaido T, Akikusa B, Virtudazo E, Yamaguchi M, Ishikura H. Regulatory role of hepatocyte nuclear factor-4alpha on gastric choriocarcinoma function. Exp Mol Pathol 2005; 80:77-84. [PMID: 15990092 DOI: 10.1016/j.yexmp.2005.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Accepted: 05/17/2005] [Indexed: 11/27/2022]
Abstract
Gastric choriocarcinoma is a highly aggressive carcinoma, most probably originating from somatic cells in the gastric mucosal layer. We herein investigated the regulatory role of hepatocyte nuclear factor (HNF)-4alpha, a transcriptional regulator expressed in non-neoplastic and neoplastic gastric tissues, on functions of gastric choriocarcinoma cells. HNF-4alpha cDNA was stably transfected to a gastric choriocarcinoma cell line, SCH. Alterations in SCH cell functions such as histology, ultrastructure, proliferation, production of trophoblast-specific proteins, and chemosensitivity to methotrexate (MTX) were examined. Neither in vitro and in vivo proliferations nor HLA-G expression differed significantly between the mock-transfected and HNF-4alpha-transfected SCH cells, while suppressed human chorionic gonadotropin (hCG) secretions, increased human placental lactogen (hPL) and carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) immunoreactivity, and decreased chemosensitivity to MTX were seen in HNF-4alpha-transfected SCH cells. General histologic features in xenograft nodules were unaltered, but, ultrastructurally, fascicles of paranuclear filaments were significantly more numerous in HNF-4alpha-transfected SCH cells. These results indicated an HNF-4alpha-rendered functional regulation in SCH cells, suggesting a role of transcriptional factors abundant in gastric but not in trophoblastic tissues/cells on the functional modulation of gastric choriocarcinoma cells.
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Affiliation(s)
- Naobumi Tochigi
- Department of Molecular Pathology, Chiba University Graduate School of Medicine, Inohana 1-8-1, Chuo-Ku, Chiba 260-8670, Japan
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70
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Shimizu T, Oishi T, Omori A, Sugiura A, Hirota K, Aoyama H, Saito T, Sugaya T, Kon Y, Engel JD, Fukamizu A, Tanimoto K. Identification of cis-regulatory sequences in the human angiotensinogen gene by transgene coplacement and site-specific recombination. Mol Cell Biol 2005; 25:2938-45. [PMID: 15798183 PMCID: PMC1069595 DOI: 10.1128/mcb.25.8.2938-2945.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The function of putative regulatory sequences identified in cell transfection experiments can be elucidated only through in vivo experimentation. However, studies of gene regulation in transgenic mice (TgM) are often compromised by the position effects, in which independent transgene insertions differ in expression depending on their location in the genome. In order to overcome such a dilemma, a method called transgene coplacement has been developed in Drosophila melanogaster. In this method, any two sequences can be positioned at exactly the same genomic site by making use of Cre/loxP recombination. Here we applied this method to mouse genetics to characterize the function of direct repeat (DR) sequences in the promoter of the human angiotensinogen (hAGT) gene, the precursor of the vasoactive octapeptide angiotensin II. We modified a hAGT bacterial artificial chromosome to use Cre/loxP recombination in utero to generate TgM lines bearing a wild-type or a mutant promoter-driven hAGT locus integrated at a single chromosomal position. The expression analyses revealed that DR sequences contribute 50 or >95% to hAGT transcription in the liver and kidneys, respectively, whereas same sequences are not required in the heart and brain. This is the first in vivo dissection of DNA cis elements that are demonstrably indispensable for regulating both the level and cell type specificity of hAGT gene transcription.
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Affiliation(s)
- Taku Shimizu
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8577, Japan.
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71
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Gupta RK, Vatamaniuk MZ, Lee CS, Flaschen RC, Fulmer JT, Matschinsky FM, Duncan SA, Kaestner KH. The MODY1 gene HNF-4alpha regulates selected genes involved in insulin secretion. J Clin Invest 2005. [PMID: 15761495 DOI: 10.1172/jci200522365] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Mutations in the gene encoding hepatocyte nuclear factor-4alpha (HNF-4alpha) result in maturity-onset diabetes of the young (MODY). To determine the contribution of HNF-4alpha to the maintenance of glucose homeostasis by the beta cell in vivo, we derived a conditional knockout of HNF-4alpha using the Cre-loxP system. Surprisingly, deletion of HNF-4alpha in beta cells resulted in hyperinsulinemia in fasted and fed mice but paradoxically also in impaired glucose tolerance. Islet perifusion and calcium-imaging studies showed abnormal responses of the mutant beta cells to stimulation by glucose and sulfonylureas. These phenotypes can be explained in part by a 60% reduction in expression of the potassium channel subunit Kir6.2. We demonstrate using cotransfection assays that the Kir6.2 gene is a transcriptional target of HNF-4alpha. Our data provide genetic evidence that HNF-4alpha is required in the pancreatic beta cell for regulation of the pathway of insulin secretion dependent on the ATP-dependent potassium channel.
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Affiliation(s)
- Rana K Gupta
- Department of Genetics, Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
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72
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Gupta RK, Vatamaniuk MZ, Lee CS, Flaschen RC, Fulmer JT, Matschinsky FM, Duncan SA, Kaestner KH. The MODY1 gene HNF-4alpha regulates selected genes involved in insulin secretion. J Clin Invest 2005; 115:1006-15. [PMID: 15761495 PMCID: PMC1059446 DOI: 10.1172/jci22365] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Accepted: 01/18/2005] [Indexed: 12/18/2022] Open
Abstract
Mutations in the gene encoding hepatocyte nuclear factor-4alpha (HNF-4alpha) result in maturity-onset diabetes of the young (MODY). To determine the contribution of HNF-4alpha to the maintenance of glucose homeostasis by the beta cell in vivo, we derived a conditional knockout of HNF-4alpha using the Cre-loxP system. Surprisingly, deletion of HNF-4alpha in beta cells resulted in hyperinsulinemia in fasted and fed mice but paradoxically also in impaired glucose tolerance. Islet perifusion and calcium-imaging studies showed abnormal responses of the mutant beta cells to stimulation by glucose and sulfonylureas. These phenotypes can be explained in part by a 60% reduction in expression of the potassium channel subunit Kir6.2. We demonstrate using cotransfection assays that the Kir6.2 gene is a transcriptional target of HNF-4alpha. Our data provide genetic evidence that HNF-4alpha is required in the pancreatic beta cell for regulation of the pathway of insulin secretion dependent on the ATP-dependent potassium channel.
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Affiliation(s)
- Rana K Gupta
- Department of Genetics, Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
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73
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Kamiya A, Inoue Y, Kodama T, Gonzalez FJ. Hepatocyte nuclear factors 1alpha and 4alpha control expression of proline oxidase in adult liver. FEBS Lett 2005; 578:63-8. [PMID: 15581617 DOI: 10.1016/j.febslet.2004.10.070] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Revised: 10/25/2004] [Accepted: 10/25/2004] [Indexed: 11/27/2022]
Abstract
Adult liver functions are regulated by several hepatocyte nuclear factors (HNFs). HNF4alpha and HNF1alpha are involved in metabolic functions in the liver. The expression of proline oxidase (PO) and proline dehydrogenase was downregulated in the HNF4alpha liver-specific null mice. In addition, the expression of PO was also diminished in the liver derived from HNF1alpha-null mice. The -160 bp proximal promoter region of the PO gene has two HNF4alpha- and HNF1alpha-binding consensus sites. Transactivation, electrophoretic mobility shift and chromatin immunoprecipitation studies revealed that these regions are important for PO promoter activity. These results suggested that HNF4alpha and HNF1alpha regulate proline metabolism in adult liver.
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Affiliation(s)
- Akihide Kamiya
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bldg 37, Rm 3106B1, 9000 Rockville Pike, Bethesda, MD 20892, USA
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74
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Watanabe Y, Jiang S, Takabe W, Ohashi R, Tanaka T, Uchiyama Y, Katsumi K, Iwanari H, Noguchi N, Naito M, Hamakubo T, Kodama T. Expression of the LXRalpha protein in human atherosclerotic lesions. Arterioscler Thromb Vasc Biol 2004; 25:622-7. [PMID: 15625283 DOI: 10.1161/01.atv.0000154489.53077.4e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Liver X-activated receptor alpha (LXRalpha) regulates multiple genes controlling cholesterol metabolism and transport. To clarify its role in atherogenesis, we established a monoclonal antibody recognizing native human LXRalpha protein and studied the expression pattern in human atherosclerotic lesions. METHODS AND RESULTS A novel monoclonal antibody PPZ0412 was raised against the ligand-binding domain of LXRalpha, which can be used for immunostaining of human LXRalpha protein. LXRalpha protein was detected in the nucleus of macrophages in the liver, spleen, or lung and also in hepatocytes and adipocytes. In atherosclerotic lesions, the LXRalpha protein was detected in macrophages positive for scavenger receptor class A and/or CD68. CONCLUSIONS In the human body, the LXRalpha protein is highly expressed in macrophage lineage cells and foam cells in atherosclerotic lesions and is identified as a target for intervention in atherosclerotic disease.
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Affiliation(s)
- Yuichiro Watanabe
- Department of Systems Biology and Medicine, Research Center for Advanced Science and Technology, the University of Tokyo, Japan
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75
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Abstract
Transcription factors provide the genetic instructions that drive pancreatic development and enable mature beta cells to function properly. To understand fully how this is accomplished, it is necessary to unravel the regulatory networks formed by transcription factors acting on their genomic targets. This article discusses recent advances in our understanding of how transcriptional networks control early pancreas organogenesis, embryonic endocrine cell formation and the differentiated function of adult beta cells. We discuss how mutations in several transcription factor genes involved in such networks cause Maturity onset diabetes of the young (MODY). Finally, we propose that pancreatic gene programs might be manipulated to generate beta cells or to enhance the function of existing beta cells, thereby providing a possible treatment of different forms of diabetes.
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Affiliation(s)
- J M Servitja
- Endocrinology, Hospital Clinic de Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
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