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Lee RA, Chang M, Tsay A, Lee YR, Li D, Yiv N, Tian S, Zhao M, O’Brien RM, Wang JC. Chronic Glucocorticoid Exposure Induced an S1PR2-RORγ Axis to Enhance Hepatic Gluconeogenesis in Male Mice. Diabetes 2023; 72:1534-1546. [PMID: 37552863 PMCID: PMC10588286 DOI: 10.2337/db22-0605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 08/01/2023] [Indexed: 08/10/2023]
Abstract
It is well established that chronic glucocorticoid exposure causes hyperglycemia. While glucocorticoid receptor (GR) stimulates hepatic gluconeogenic gene transcription, additional mechanisms are activated by chronic glucocorticoid exposure to enhance gluconeogenesis. We found that chronic glucocorticoid treatment activated sphingosine-1-phosphate (S1P)-mediated signaling. Hepatic knockdown of hepatic S1P receptor 1 (S1PR1) had no effect on chronic glucocorticoid-induced glucose intolerance but elevated fasting plasma insulin levels. In contrast, hepatic S1PR3 knockdown exacerbated chronic glucocorticoid-induced glucose intolerance without affecting fasting plasma insulin levels. Finally, hepatic S1PR2 knockdown attenuated chronic glucocorticoid-induced glucose intolerance and reduced fasting plasma insulin levels. Here, we focused on dissecting the role of S1PR2 signaling in chronic glucocorticoid response on glucose homeostasis. We found that chronic glucocorticoid-induced hepatic gluconeogenesis, gluconeogenic gene expression, and GR recruitment to the glucocorticoid response elements (GREs) of gluconeogenic genes were all reduced in hepatic S1PR2 knockdown male mice. Hepatic S1PR2 knockdown also enhanced glucocorticoid suppression of RAR-related orphan receptor γ (RORγ) expression. Hepatic RORγ overexpression in hepatic S1PR2 knockdown mice restored glucocorticoid-induced glucose intolerance, gluconeogenic gene expression, and GR recruitment to their GREs. Conversely, RORγ antagonist and the reduction of hepatic RORγ expression attenuated such glucocorticoid effects. Thus, chronic glucocorticoid exposure induces an S1PR2-RORγ axis to cooperate with GR to enhance hepatic gluconeogenesis. Overall, this work provides novel mechanisms of and pharmaceutical targets against steroid-induced hyperglycemia. ARTICLE HIGHLIGHTS
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Affiliation(s)
- Rebecca A. Lee
- Endocrinology Graduate Program, University of California Berkeley, Berkeley, CA
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA
| | - Maggie Chang
- Endocrinology Graduate Program, University of California Berkeley, Berkeley, CA
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA
| | - Ariel Tsay
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA
- Metabolic Biology Graduate Program, University of California Berkeley, Berkeley, CA
| | - Yeong Rim Lee
- Endocrinology Graduate Program, University of California Berkeley, Berkeley, CA
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA
| | - Danielle Li
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA
| | - Nicholas Yiv
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA
- Metabolic Biology Graduate Program, University of California Berkeley, Berkeley, CA
| | - Sharon Tian
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA
| | - Michelle Zhao
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA
| | - Richard M. O’Brien
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Jen-Chywan Wang
- Endocrinology Graduate Program, University of California Berkeley, Berkeley, CA
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA
- Metabolic Biology Graduate Program, University of California Berkeley, Berkeley, CA
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2
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Manteuffel C, Spitschak M, Ludwig C, Wirthgen E. New Perspectives In The Objective Evaluation Of Animal Welfare, With Focus On The Domestic Pig. J APPL ANIM WELF SCI 2023; 26:518-529. [PMID: 34727795 DOI: 10.1080/10888705.2021.1998774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Animal welfare can be viewed as the result of integrating repeated affective evaluations of success in coping with environmental challenges, i.e., subjective challenge adequacy. The present work summarizes why established physiological and behavioral welfare parameters are inadequate to assess challenge adequacy. Behavioral tests based on the mood-congruent judgment effect and physiologic parameters based on components of the somatotropic axis are proposed as an alternative. Here, the judgment bias measures an animal's subjective confidence to cope successfully with a challenge, which is in turn modulated by the animal's previous experience. The somatotropic axis incorporates the insulin-like growth factor (IGF) and its binding proteins (IGFBP), which are involved in the regulation of metabolism and growth. First results indicate that in particular IGF-1 and IGFBP-3 react with higher latency and higher inertness to short-term stressful events than established physiological stress parameters. Before these indicators can be utilized for overall welfare assessment, further validation studies are necessary that provide more insights into how repeatable the measurements are under different conditions and which other factors may confound the measures.
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Affiliation(s)
- Christian Manteuffel
- Leibniz Institute of Farm Animal Biology, Institute of Behavioural Physiology, Ethology Unit, Dummerstorf, Germany
- Department of Mucosal Immunity, Rostock University Medical Center, Rostock, Germany
| | - Marion Spitschak
- Leibniz Institute of Farm Animal Biology, Institute of Genome Biology, Signal Transduction Unit, Dummerstorf, Germany
| | - Carolin Ludwig
- Leibniz Institute of Farm Animal Biology,Institute of Reproductive Biology, Reproductive Biochemistry Unit, Dummerstorf, Germany
| | - Elisa Wirthgen
- Leibniz Institute of Farm Animal Biology, Institute of Genome Biology, Signal Transduction Unit, Dummerstorf, Germany
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Vargas-Alarcón G, Fragoso JM, Ramírez-Bello J, Posadas-Sánchez R. FOXA3 Polymorphisms Are Associated with Metabolic Parameters in Individuals with Subclinical Atherosclerosis and Healthy Controls-The GEA Mexican Study. Biomolecules 2022; 12:biom12050601. [PMID: 35625529 PMCID: PMC9139129 DOI: 10.3390/biom12050601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/11/2022] [Accepted: 04/15/2022] [Indexed: 11/16/2022] Open
Abstract
FOXA3 is a transcription factor involved in the macrophage cholesterol efflux and macrophage reverse cholesterol transport reducing the atherosclerotic lesions. Thus, the present study aimed to establish if the FOXA3 polymorphisms are associated with subclinical atherosclerosis (SA) and cardiometabolic parameters. Two FOXA3 polymorphisms (rs10410870 and rs10412574) were determined in 386 individuals with SA and 1070 controls. No association with SA was observed. The rs10410870 polymorphism was associated with a low risk of having total cholesterol >200 mg/dL, non-HDL-cholesterol > 160 mg/dL, and a high risk of having LDL pattern B and insulin resistance adipose tissue in individuals with SA, and with a high risk of having interleukin 10 <p25 and magnesium deficiency in controls. The rs10412574 polymorphism was associated with a low risk of insulin resistance of the adipose tissue and a high risk of aspartate aminotransferase >p75 in individuals with SA, and with a low risk of LDL pattern B and a high risk of a magnesium deficiency in controls. Independent analysis in 846 individuals showed that the rs10410870 polymorphism was associated with a high risk of aortic valve calcification. In summary, FOXA3 polymorphisms were not associated with SA; however, they were associated with cardiometabolic parameters in individuals with and without SA.
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Affiliation(s)
- Gilberto Vargas-Alarcón
- Department of Molecular Biology and Research Direction, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City 14080, Mexico; (G.V.-A.); (J.M.F.)
| | - José Manuel Fragoso
- Department of Molecular Biology and Research Direction, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City 14080, Mexico; (G.V.-A.); (J.M.F.)
| | - Julian Ramírez-Bello
- Department of Endocrinology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City 14080, Mexico;
| | - Rosalinda Posadas-Sánchez
- Department of Endocrinology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City 14080, Mexico;
- Correspondence: ; Tel.: +52-55-55732911 (ext. 21416)
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The "Adipo-Cerebral" Dialogue in Childhood Obesity: Focus on Growth and Puberty. Physiopathological and Nutritional Aspects. Nutrients 2021; 13:nu13103434. [PMID: 34684432 PMCID: PMC8539184 DOI: 10.3390/nu13103434] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/18/2021] [Accepted: 09/21/2021] [Indexed: 01/08/2023] Open
Abstract
Overweight and obesity in children and adolescents are overwhelming problems in western countries. Adipocytes, far from being only fat deposits, are capable of endocrine functions, and the endocrine activity of adipose tissue, resumable in adipokines production, seems to be a key modulator of central nervous system function, suggesting the existence of an “adipo-cerebral axis.” This connection exerts a key role in children growth and puberty development, and it is exemplified by the leptin–kisspeptin interaction. The aim of this review was to describe recent advances in the knowledge of adipose tissue endocrine functions and their relations with nutrition and growth. The peculiarities of major adipokines are briefly summarized in the first paragraph; leptin and its interaction with kisspeptin are focused on in the second paragraph; the third paragraph deals with the regulation of the GH-IGF axis, with a special focus on the model represented by growth hormone deficiency (GHD); finally, old and new nutritional aspects are described in the last paragraph.
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5
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Caputo M, Pigni S, Agosti E, Daffara T, Ferrero A, Filigheddu N, Prodam F. Regulation of GH and GH Signaling by Nutrients. Cells 2021; 10:1376. [PMID: 34199514 PMCID: PMC8227158 DOI: 10.3390/cells10061376] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 02/06/2023] Open
Abstract
Growth hormone (GH) and insulin-like growth factor-1 (IGF-I) are pleiotropic hormones with important roles in lifespan. They promote growth, anabolic actions, and body maintenance, and in conditions of energy deprivation, favor catabolic feedback mechanisms switching from carbohydrate oxidation to lipolysis, with the aim to preserve protein storages and survival. IGF-I/insulin signaling was also the first one identified in the regulation of lifespan in relation to the nutrient-sensing. Indeed, nutrients are crucial modifiers of the GH/IGF-I axis, and these hormones also regulate the complex orchestration of utilization of nutrients in cell and tissues. The aim of this review is to summarize current knowledge on the reciprocal feedback among the GH/IGF-I axis, macro and micronutrients, and dietary regimens, including caloric restriction. Expanding the depth of information on this topic could open perspectives in nutrition management, prevention, and treatment of GH/IGF-I deficiency or excess during life.
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Affiliation(s)
- Marina Caputo
- SCDU of Endocrinology, University Hospital Maggiore della Carità, 28100 Novara, Italy; (M.C.); (S.P.); (T.D.); (A.F.)
- Department of Health Sciences, Università del Piemonte Orientale, 28100 Novara, Italy;
| | - Stella Pigni
- SCDU of Endocrinology, University Hospital Maggiore della Carità, 28100 Novara, Italy; (M.C.); (S.P.); (T.D.); (A.F.)
| | - Emanuela Agosti
- Department of Health Sciences, Università del Piemonte Orientale, 28100 Novara, Italy;
| | - Tommaso Daffara
- SCDU of Endocrinology, University Hospital Maggiore della Carità, 28100 Novara, Italy; (M.C.); (S.P.); (T.D.); (A.F.)
| | - Alice Ferrero
- SCDU of Endocrinology, University Hospital Maggiore della Carità, 28100 Novara, Italy; (M.C.); (S.P.); (T.D.); (A.F.)
| | - Nicoletta Filigheddu
- Department of Translational Medicine, Università del Piemonte Orientale, 28100 Novara, Italy;
| | - Flavia Prodam
- SCDU of Endocrinology, University Hospital Maggiore della Carità, 28100 Novara, Italy; (M.C.); (S.P.); (T.D.); (A.F.)
- Department of Health Sciences, Università del Piemonte Orientale, 28100 Novara, Italy;
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6
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Budi EH, Hoffman S, Gao S, Zhang YE, Derynck R. Integration of TGF-β-induced Smad signaling in the insulin-induced transcriptional response in endothelial cells. Sci Rep 2019; 9:16992. [PMID: 31740700 PMCID: PMC6861289 DOI: 10.1038/s41598-019-53490-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/22/2019] [Indexed: 01/09/2023] Open
Abstract
Insulin signaling governs many processes including glucose homeostasis and metabolism, and is therapeutically used to treat hyperglycemia in diabetes. We demonstrated that insulin-induced Akt activation enhances the sensitivity to TGF-β by directing an increase in cell surface TGF-β receptors from a pool of intracellular TGF-β receptors. Consequently, increased autocrine TGF-β signaling in response to insulin participates in insulin-induced angiogenic responses of endothelial cells. With TGF-β signaling controlling many cell responses, including differentiation and extracellular matrix deposition, and pathologically promoting fibrosis and cancer cell dissemination, we addressed to which extent autocrine TGF-β signaling participates in insulin-induced gene responses of human endothelial cells. Transcriptome analyses of the insulin response, in the absence or presence of a TGF-β receptor kinase inhibitor, revealed substantial positive and negative contributions of autocrine TGF-β signaling in insulin-responsive gene responses. Furthermore, insulin-induced responses of many genes depended on or resulted from autocrine TGF-β signaling. Our analyses also highlight extensive contributions of autocrine TGF-β signaling to basal gene expression in the absence of insulin, and identified many novel TGF-β-responsive genes. This data resource may aid in the appreciation of the roles of autocrine TGF-β signaling in normal physiological responses to insulin, and implications of therapeutic insulin usage.
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Affiliation(s)
- Erine H Budi
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, CA, 94143-0669, USA
| | - Steven Hoffman
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, CA, 94143-0669, USA
| | - Shaojian Gao
- Thoracic and Gastrointestinal Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892-1906, USA
| | - Ying E Zhang
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, 20892-4256, USA
| | - Rik Derynck
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, CA, 94143-0669, USA.
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7
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Li Y, Xu Y, Jadhav K, Zhu Y, Yin L, Zhang Y. Hepatic Forkhead Box Protein A3 Regulates ApoA-I (Apolipoprotein A-I) Expression, Cholesterol Efflux, and Atherogenesis. Arterioscler Thromb Vasc Biol 2019; 39:1574-1587. [PMID: 31291759 DOI: 10.1161/atvbaha.119.312610] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To determine the role of hepatic FOXA3 (forkhead box A3) in lipid metabolism and atherosclerosis. Approach and Results: Hepatic FOXA3 expression was reduced in diabetic or high fat diet-fed mice or patients with nonalcoholic steatohepatitis. We then used adenoviruses to overexpress or knock down hepatic FOXA3 expression. Overexpression of FOXA3 in the liver increased hepatic ApoA-I (apolipoprotein A-I) expression, plasma HDL-C (high-density lipoprotein cholesterol) level, macrophage cholesterol efflux, and macrophage reverse cholesterol transport. In contrast, knockdown of hepatic FOXA3 expression had opposite effects. We further showed that FOXA3 directly bound to the promoter of the Apoa1 gene to regulate its transcription. Finally, AAV8 (adeno-associated virus serotype 8)-mediated overexpression of human FOXA3 in the hepatocytes of Apoe-/- (apolipoprotein E-deficient) mice raised plasma HDL-C levels and significantly reduced atherosclerotic lesions. CONCLUSIONS Hepatocyte FOXA3 protects against atherosclerosis by inducing ApoA-I and macrophage reverse cholesterol transport.
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Affiliation(s)
- Yuanyuan Li
- From the Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown
| | - Yanyong Xu
- From the Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown
| | - Kavita Jadhav
- From the Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown
| | - Yingdong Zhu
- From the Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown
| | - Liya Yin
- From the Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown
| | - Yanqiao Zhang
- From the Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown
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8
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Li K, Qiu C, Sun P, Liu DC, Wu TJ, Wang K, Zhou YC, Chang XA, Yin Y, Chen F, Zhu YX, Han X. Ets1-Mediated Acetylation of FoxO1 Is Critical for Gluconeogenesis Regulation during Feed-Fast Cycles. Cell Rep 2019; 26:2998-3010.e5. [DOI: 10.1016/j.celrep.2019.02.035] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/22/2018] [Accepted: 02/11/2019] [Indexed: 10/27/2022] Open
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9
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Vo TM, Burchett R, Brun M, Monckton EA, Poon HY, Godbout R. Effects of nuclear factor I phosphorylation on calpastatin ( CAST) gene variant expression and subcellular distribution in malignant glioma cells. J Biol Chem 2019; 294:1173-1188. [PMID: 30504225 DOI: 10.1074/jbc.ra118.004787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 11/29/2018] [Indexed: 12/20/2022] Open
Abstract
Malignant glioma (MG) is the most lethal primary brain tumor. In addition to having inherent resistance to radiation treatment and chemotherapy, MG cells are highly infiltrative, rendering focal therapies ineffective. Genes involved in MG cell migration and glial cell differentiation are up-regulated by hypophosphorylated nuclear factor I (NFI), which is dephosphorylated by the phosphatase calcineurin in MG cells. Calcineurin is cleaved and thereby activated by calpain proteases, which are, in turn, inhibited by calpastatin (CAST). Here, we show that the CAST gene is a target of NFI and has NFI-binding sites in its intron 3 region. We also found that NFI-mediated regulation of CAST depends on NFI's phosphorylation state. We noted that occupation of CAST intron 3 by hypophosphorylated NFI results in increased activation of an alternative promoter. This activation resulted in higher levels of CAST transcript variants, leading to increased levels of CAST protein that lacks the N-terminal XL domain. CAST was primarily present in the cytoplasm of NFI-hypophosphorylated MG cells, with a predominantly perinuclear immunostaining pattern. NFI knockdown in NFI-hypophosphorylated MG cells increased CAST levels at the plasma membrane. These results suggest that NFI plays an integral role in the regulation of CAST variants and CAST subcellular distribution. Along with the previous findings indicating that NFI activity is regulated by calcineurin, these results provide a foundation for further investigations into the possibility of regulatory cross-talk between NFI and the CAST/calpain/calcineurin signaling pathway in MG cells.
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Affiliation(s)
- The Minh Vo
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta T6G 1Z2, Canada
| | - Rebecca Burchett
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta T6G 1Z2, Canada
| | - Miranda Brun
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta T6G 1Z2, Canada
| | - Elizabeth A Monckton
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta T6G 1Z2, Canada
| | - Ho-Yin Poon
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta T6G 1Z2, Canada
| | - Roseline Godbout
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta T6G 1Z2, Canada.
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Beddow SA, Gattu AK, Vatner DF, Paolella L, Alqarzaee A, Tashkandi N, Popov VB, Church CD, Rodeheffer MS, Cline GW, Geisler JG, Bhanot S, Samuel VT. PEPCK1 Antisense Oligonucleotide Prevents Adiposity and Impairs Hepatic Glycogen Synthesis in High-Fat Male Fed Rats. Endocrinology 2019; 160:205-219. [PMID: 30445425 PMCID: PMC6307100 DOI: 10.1210/en.2018-00630] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/06/2018] [Indexed: 11/19/2022]
Abstract
The increased hepatic gluconeogenesis in type 2 diabetes mellitus has often been ascribed to increased transcription of phosphoenolpyruvate carboxykinase 1, cystolic form (PEPCK1), although recent evidence has questioned this attribution. To assess the metabolic role of PEPCK1, we treated regular chow fed and high-fat fed (HFF) male Sprague-Dawley rats with a 2'-O-methoxyethyl chimeric antisense oligonucleotide (ASO) against PEPCK1 and compared them with control ASO-treated rats. PEPCK1 ASO effectively decreased PEPCK1 expression in the liver and white adipose tissue. In chow fed rats, PEPCK1 ASO did not alter adiposity, plasma glucose, or insulin. In contrast, PEPCK1 ASO decreased the white adipose tissue mass in HFF rats but without altering basal rates of lipolysis, de novo lipogenesis, or glyceroneogenesis in vivo. Despite the protection from adiposity, hepatic insulin sensitivity was impaired in HFF PEPCK1 ASO-treated rats. PEPCK1 ASO worsened hepatic steatosis, although without additional impairments in hepatic insulin signaling or activation of inflammatory signals in the liver. Instead, the development of hepatic insulin resistance and the decrease in hepatic glycogen synthesis during a hyperglycemic clamp was attributed to a decrease in hepatic glucokinase (GCK) expression and decreased synthesis of glycogen via the direct pathway. The decrease in GCK expression was associated with increased expression of activating transcription factor 3, a negative regulator of GCK transcription. These studies have demonstrated that PEPCK1 is integral to coordinating cellular metabolism in the liver and adipose tissue, although it does not directly effect hepatic glucose production or adipose glyceroneogenesis.
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Affiliation(s)
- Sara A Beddow
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- West Haven Veterans Affairs Medical Center, West Haven, Connecticut
| | - Arijeet K Gattu
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- West Haven Veterans Affairs Medical Center, West Haven, Connecticut
| | - Daniel F Vatner
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Lauren Paolella
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- West Haven Veterans Affairs Medical Center, West Haven, Connecticut
| | | | - Nedda Tashkandi
- West Haven Veterans Affairs Medical Center, West Haven, Connecticut
| | - Violeta B Popov
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Christopher D Church
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Matthew S Rodeheffer
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Gary W Cline
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | | | | | - Varman T Samuel
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- West Haven Veterans Affairs Medical Center, West Haven, Connecticut
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11
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Brun M, Jain S, Monckton EA, Godbout R. Nuclear Factor I Represses the Notch Effector HEY1 in Glioblastoma. Neoplasia 2018; 20:1023-1037. [PMID: 30195713 PMCID: PMC6138789 DOI: 10.1016/j.neo.2018.08.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 08/17/2018] [Accepted: 08/20/2018] [Indexed: 01/16/2023] Open
Abstract
Glioblastomas (GBMs) are highly aggressive brain tumors with a dismal prognosis. Nuclear factor I (NFI) is a family of transcription factors that controls glial cell differentiation in the developing central nervous system. NFIs have previously been shown to regulate the expression of astrocyte markers such as glial fibrillary acidic protein (GFAP) in both normal brain and GBM cells. We used chromatin immunoprecipitation (ChIP)–on-chip to identify additional NFI targets in GBM cells. Analysis of our ChIP data revealed ~400 putative NFI target genes including an effector of the Notch signaling pathway, HEY1, implicated in the maintenance of neural stem cells. All four NFIs (NFIA, NFIB, NFIC, and NFIX) bind to NFI recognition sites located within 1 kb upstream of the HEY1 transcription site. We further showed that NFI negatively regulates HEY1 expression, with knockdown of all four NFIs in GBM cells resulting in increased HEY1 RNA levels. HEY1 knockdown in GBM cells decreased cell proliferation, increased cell migration, and decreased neurosphere formation. Finally, we found a general correlation between elevated levels of HEY1 and expression of the brain neural stem/progenitor cell marker B-FABP in GBM cell lines. Knockdown of HEY1 resulted in an increase in the RNA levels of the GFAP astrocyte differentiation marker. Overall, our data indicate that HEY1 is negatively regulated by NFI family members and is associated with increased proliferation, decreased migration, and increased stem cell properties in GBM cells.
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Affiliation(s)
- Miranda Brun
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada, T6G 1Z2
| | - Saket Jain
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada, T6G 1Z2
| | - Elizabeth A Monckton
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada, T6G 1Z2
| | - Roseline Godbout
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada, T6G 1Z2.
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12
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Schill D, Nord J, Cirillo LA. FoxO1 and FoxA1/2 form a complex on DNA and cooperate to open chromatin at insulin-regulated genes. Biochem Cell Biol 2018; 97:118-129. [PMID: 30142277 DOI: 10.1139/bcb-2018-0104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We have previously shown that cooperative, interdependent binding by the pioneer factors FoxO1 and FoxA1/2 is required for recruitment of RNA polymerase II and H3K27 acetylation to the promoters of insulin-regulated genes. However, the underlying mechanisms are unknown. In this study, we demonstrate that, in HepG2 cells, FoxO1 and FoxA2 form a complex on DNA that is disrupted by insulin treatment. Insulin-mediated phosphorylation of FoxO1 and FoxA2 does not impair their cooperative binding to mononucleosome particles assembled from the IGFBP1 promoter, indicating that direct disruption of complex formation by phosphorylation is not responsible for the loss of interdependent FoxO1:FoxA1/2 binding following insulin treatment. Since FoxO1 and FoxA1/2 binding is required for the establishment and maintenance of transcriptionally active chromatin at insulin-regulated genes, we hypothesized that cooperative FoxO1 and FoxA1/2 binding dictates the chromatin remodeling events required for the initial activation of these genes. In support of this idea, we demonstrate that FoxO1 and FoxA2 cooperatively open linker histone compacted chromatin templates containing the IGFBP1 promoter. Taken together, these results provide a mechanism for how interdependent FoxO1:FoxA1/2 binding is negatively impacted by insulin and provide a developmental context for cooperative gene activation by these factors.
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Affiliation(s)
- Daniel Schill
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.,Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Joshua Nord
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.,Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Lisa Ann Cirillo
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.,Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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Unterman TG. Regulation of Hepatic Glucose Metabolism by FoxO Proteins, an Integrated Approach. Curr Top Dev Biol 2018; 127:119-147. [DOI: 10.1016/bs.ctdb.2017.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Allard JB, Duan C. IGF-Binding Proteins: Why Do They Exist and Why Are There So Many? Front Endocrinol (Lausanne) 2018; 9:117. [PMID: 29686648 PMCID: PMC5900387 DOI: 10.3389/fendo.2018.00117] [Citation(s) in RCA: 301] [Impact Index Per Article: 50.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 03/08/2018] [Indexed: 12/11/2022] Open
Abstract
Insulin-like growth factors (IGFs) are key growth-promoting peptides that act as both endocrine hormones and autocrine/paracrine growth factors. In the bloodstream and in local tissues, most IGF molecules are bound by one of the members of the IGF-binding protein (IGFBP) family, of which six distinct types exist. These proteins bind to IGF with an equal or greater affinity than the IGF1 receptor and are thus in a key position to regulate IGF signaling globally and locally. Binding to an IGFBP increases the half-life of IGF in the circulation and blocks its potential binding to the insulin receptor. In addition to these classical roles, IGFBPs have been shown to modulate IGF signaling locally under various conditions. Although members of the IGFBP family share significant sequence homology, they each have unique structural features and play distinct roles. These IGFBP genes also have different modes of regulation and distinct expression patterns. Some IGFBPs have been found to bind to their own receptors or to translocate into the interior compartments of cells where they may execute IGF-independent actions. In spite of this functional and regulatory diversity, it has been puzzling that loss-of-function studies have yielded relatively little information about the physiological functions of IGFBPs. In this review, we suggest that evolution has tended to retain an array of IGFBPs in order to facilitate fine-tuning of IGF signaling. We explore the emerging explanation that many IGFBP functions have evolved to allow the targeted adjustment of IGF signaling under stressful or irregular conditions, which would likely not be revealed in a standard laboratory setting.
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Kanaki M, Kardassis D. Regulation of the human lipoprotein lipase gene by the forkhead box transcription factor FOXA2/HNF-3β in hepatic cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:327-336. [DOI: 10.1016/j.bbagrm.2017.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/13/2017] [Accepted: 01/13/2017] [Indexed: 12/11/2022]
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Cui Y, Qiao A, Jiao T, Zhang H, Xue Y, Zou Y, Cui A, Fang F, Chang Y. The hepatic FOXQ1 transcription factor regulates glucose metabolism in mice. Diabetologia 2016; 59:2229-39. [PMID: 27421728 DOI: 10.1007/s00125-016-4043-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 06/10/2016] [Indexed: 11/25/2022]
Abstract
AIM/HYPOTHESIS Hepatic forkhead box q1 (FOXQ1) expression levels are regulated by nutritional and pathophysiological status. In this study we investigated the role of FOXQ1 in the regulation of hepatic gluconeogenesis. METHODS We used multiple mouse and cell models to study the role of FOXQ1 in regulating expression of gluconeogenic genes, and cellular and hepatic glucose production. RESULTS Expression of hepatic FOXQ1 was regulated by fasting in normal mice and was dysregulated in diabetic mice. Overexpression of FOXQ1 in primary hepatocytes inhibited expression of gluconeogenic genes and decreased cellular glucose output. Hepatic FOXQ1 rescue in db/db and high-fat diet-induced obese mice markedly decreased blood glucose level and improved glucose intolerance. In contrast, wild-type C57 mice with hepatic FOXQ1 deficiency displayed increased blood glucose levels and impaired glucose tolerance. Interestingly, studies into molecular mechanisms indicated that FOXQ1 interacts with FOXO1, thereby blocking FOXO1 activity on hepatic gluconeogenesis, preventing it from directly binding to insulin response elements mapped in the promoter region of gluconeogenic genes. CONCLUSIONS/INTERPRETATION FOXQ1 is a novel factor involved in regulating hepatic gluconeogenesis, and the decreased FOXQ1 expression in liver may contribute to the development of type 2 diabetes.
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Affiliation(s)
- Ying Cui
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, People's Republic of China
| | - Aijun Qiao
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, People's Republic of China
| | - Tao Jiao
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, People's Republic of China
| | - Huabing Zhang
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, People's Republic of China
| | - Yuan Xue
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, People's Republic of China
| | - Yongkang Zou
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, People's Republic of China
| | - Anfang Cui
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, People's Republic of China
| | - Fude Fang
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, People's Republic of China
| | - Yongsheng Chang
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, 5 Dong Dan San Tiao, Beijing, 100005, People's Republic of China.
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Zou Y, Gong N, Cui Y, Wang X, Cui A, Chen Q, Jiao T, Dong X, Yang H, Zhang S, Fang F, Chang Y. Forkhead Box P1 (FOXP1) Transcription Factor Regulates Hepatic Glucose Homeostasis. J Biol Chem 2015; 290:30607-15. [PMID: 26504089 DOI: 10.1074/jbc.m115.681627] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Indexed: 11/06/2022] Open
Abstract
Dysregulation of hepatic gluconeogenesis contributes to the pathogenesis of diabetes, yet the detailed molecular mechanisms remain to be fully elucidated. Here we show that FOXP1, a transcriptional repressor, plays a key role in the regulation of systemic glucose homeostasis. Hepatic expression levels of FOXP1 are decreased in diabetic mice. Modest hepatic overexpression of FOXP1 in mice inhibited the expression of gluconeogenic genes, such as peroxisome proliferators-activated receptor γ coactivator-1α (PGC-1α), phosphoenolpyruvate carboxykinase (PEPCK), and glucose-6-phosphatase (G6PC), leading to a decrease in hepatic glucose production and fasting blood glucose levels in normal mice and different mouse models of diabetes, including db/db diabetic and high-fat diet-induced obese mice. FOXP1 physically interacted with FOXO1 in vivo and competed with FOXO1 for binding to the insulin response element in the promoter region of gluconeogenic genes, thereby interfering expression of these genes. These results identify a previously unrecognized role for FOXP1 in the transcriptional control of hepatic glucose homeostasis.
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Affiliation(s)
- Yongkang Zou
- From the National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China and
| | - Ning Gong
- From the National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China and
| | - Ying Cui
- From the National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China and
| | - Xiaojuan Wang
- From the National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China and
| | - Anfang Cui
- From the National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China and
| | - Qi Chen
- From the National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China and
| | - Tao Jiao
- From the National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China and
| | - Xueyu Dong
- From the National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China and
| | - Hao Yang
- From the National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China and
| | - Shutian Zhang
- the Beijing Friendship Hospital Affiliated to the Capital Medical University, Beijing Key Laboratory for Precancerous Lesion of Digestive Diseases, Beijing Digestive Disease Center, Beijing, China
| | - Fude Fang
- From the National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China and
| | - Yongsheng Chang
- From the National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China and
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18
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Gao X, Goggin K, Dowling C, Qian J, Hawdon JM. Two potential hookworm DAF-16 target genes, SNR-3 and LPP-1: gene structure, expression profile, and implications of a cis-regulatory element in the regulation of gene expression. Parasit Vectors 2015; 8:14. [PMID: 25573064 PMCID: PMC4298947 DOI: 10.1186/s13071-014-0609-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 12/16/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hookworms infect nearly 700 million people, causing anemia and developmental stunting in heavy infections. Little is known about the genomic structure or gene regulation in hookworms, although recent publication of draft genome assemblies has allowed the first investigations of these topics to be undertaken. The transcription factor DAF-16 mediates multiple developmental pathways in the free living nematode Caenorhabditis elegans, and is involved in the recovery from the developmentally arrested L3 in hookworms. Identification of downstream targets of DAF-16 will provide a better understanding of the molecular mechanism of hookworm infection. METHODS Genomic Fragment 2.23 containing a DAF-16 binding element (DBE) was used to identify overlapping complementary expressed sequence tags (ESTs). These sequences were used to search a draft assembly of the Ancylostoma caninum genome, and identified two neighboring genes, snr-3 and lpp-1, in a tail-to-tail orientation. Expression patterns of both genes during parasitic development were determined by qRT-PCR. DAF-16 dependent cis-regulatory activity of fragment 2.23 was investigated using an in vitro reporter system. RESULTS The snr-3 gene spans approximately 5.6 kb in the genome and contains 3 exons and 2 introns, and contains the DBE in its 3' untranslated region. Downstream from snr-3 in a tail-to-tail arrangement is the gene lpp-1. The lpp-1 gene spans more than 6 kb and contains 10 exons and 9 introns. The A. caninum genome contains 2 apparent splice variants, but there are 7 splice variants in the A. ceylanicum genome. While the gene order is similar, the gene structures of the hookworm genes differ from their C. elegans orthologs. Both genes show peak expression in the late L4 stage. Using a cell culture based expression system, fragment 2.23 was found to have both DAF-16-dependent promoter and enhancer activity that required an intact DBE. CONCLUSIONS Two putative DAF-16 targets were identified by genome wide screening for DAF-16 binding elements. Aca-snr-3 encodes a core small nuclear ribonucleoprotein, and Aca-lpp-1 encodes a lipid phosphate phosphohydrolase. Expression of both genes peaked at the late L4 stage, suggesting a role in L4 development. The 3'-terminal genomic fragment of the snr-3 gene displayed Ac-DAF-16-dependent cis-regulatory activity.
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Affiliation(s)
- Xin Gao
- Current affiliation: The Genome Institute at Washington University, 4444 Forest Park Ave, St. Louis, MO, 63108, USA.
| | - Kevin Goggin
- Department of Microbiology and Tropical Medicine, The George Washington University Medical Center, Washington, DC, USA.
| | - Camille Dowling
- Department of Microbiology and Tropical Medicine, The George Washington University Medical Center, Washington, DC, USA.
| | - Jason Qian
- Department of Microbiology and Tropical Medicine, The George Washington University Medical Center, Washington, DC, USA.
| | - John M Hawdon
- Department of Microbiology and Tropical Medicine, The George Washington University Medical Center, Washington, DC, USA.
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Rose AJ, Herzig S. Metabolic control through glucocorticoid hormones: an update. Mol Cell Endocrinol 2013; 380:65-78. [PMID: 23523966 DOI: 10.1016/j.mce.2013.03.007] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 02/21/2013] [Accepted: 03/08/2013] [Indexed: 01/28/2023]
Abstract
In the past decades, glucocorticoid (GC) hormones and their cognate, intracellular receptor, the glucocorticoid receptor (GR), have been well established as critical checkpoints in mammalian energy homeostasis. Whereas many aspects in healthy nutrient metabolism require physiological levels and/or action of GC, aberrant GC/GR signalling has been linked to severe metabolic dysfunction, including obesity, insulin resistance and type 2 diabetes. Consequently, studies of the molecular mechanisms within the GC signalling axis have become a major focus in biomedical research, up-to-date particularly focusing on systemic glucose and lipid handling. However, with the availability of novel high throughput technologies and more sophisticated metabolic phenotyping capabilities, as-yet non-appreciated, metabolic functions of GC have been recently discovered, including regulatory roles of the GC/GR axis in protein and bile acid homeostasis as well as metabolic inter-organ communication. Therefore, this review summarises recent advances in GC/GR biology, and summarises findings relevant for basic and translational metabolic research.
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Affiliation(s)
- Adam J Rose
- Joint Research Division, Molecular Metabolic Control, German Cancer Research Center (DKFZ) Heidelberg, Center for Molecular Biology (ZMBH), Heidelberg University, Network Aging Research, University Hospital Heidelberg, Germany
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Kumashiro N, Beddow SA, Vatner DF, Majumdar SK, Cantley JL, Guebre-Egziabher F, Fat I, Guigni B, Jurczak MJ, Birkenfeld AL, Kahn M, Perler BK, Puchowicz MA, Manchem VP, Bhanot S, Still CD, Gerhard GS, Petersen KF, Cline GW, Shulman GI, Samuel VT. Targeting pyruvate carboxylase reduces gluconeogenesis and adiposity and improves insulin resistance. Diabetes 2013; 62:2183-94. [PMID: 23423574 PMCID: PMC3712050 DOI: 10.2337/db12-1311] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We measured the mRNA and protein expression of the key gluconeogenic enzymes in human liver biopsy specimens and found that only hepatic pyruvate carboxylase protein levels related strongly with glycemia. We assessed the role of pyruvate carboxylase in regulating glucose and lipid metabolism in rats through a loss-of-function approach using a specific antisense oligonucleotide (ASO) to decrease expression predominantly in liver and adipose tissue. Pyruvate carboxylase ASO reduced plasma glucose concentrations and the rate of endogenous glucose production in vivo. Interestingly, pyruvate carboxylase ASO also reduced adiposity, plasma lipid concentrations, and hepatic steatosis in high fat-fed rats and improved hepatic insulin sensitivity. Pyruvate carboxylase ASO had similar effects in Zucker Diabetic Fatty rats. Pyruvate carboxylase ASO did not alter de novo fatty acid synthesis, lipolysis, or hepatocyte fatty acid oxidation. In contrast, the lipid phenotype was attributed to a decrease in hepatic and adipose glycerol synthesis, which is important for fatty acid esterification when dietary fat is in excess. Tissue-specific inhibition of pyruvate carboxylase is a potential therapeutic approach for nonalcoholic fatty liver disease, hepatic insulin resistance, and type 2 diabetes.
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Affiliation(s)
- Naoki Kumashiro
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Sara A. Beddow
- Veterans Affairs Medical Center, West Haven, Connecticut
| | - Daniel F. Vatner
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Sachin K. Majumdar
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Jennifer L. Cantley
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | | | - Ioana Fat
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Blas Guigni
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Michael J. Jurczak
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Andreas L. Birkenfeld
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Mario Kahn
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Bryce K. Perler
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | | | | | | | | | - Glenn S. Gerhard
- Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania
| | - Kitt Falk Petersen
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Gary W. Cline
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Gerald I. Shulman
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
| | - Varman T. Samuel
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Veterans Affairs Medical Center, West Haven, Connecticut
- Corresponding author: Varman T. Samuel,
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21
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Baerenwald DA, Bonnefond A, Bouatia-Naji N, Flemming BP, Umunakwe OC, Oeser JK, Pound LD, Conley NL, Cauchi S, Lobbens S, Eury E, Balkau B, Lantieri O, Dadi PK, Jacobson DA, Froguel P, O’Brien RM. Multiple functional polymorphisms in the G6PC2 gene contribute to the association with higher fasting plasma glucose levels. Diabetologia 2013; 56:1306-16. [PMID: 23508304 PMCID: PMC4106008 DOI: 10.1007/s00125-013-2875-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/28/2013] [Indexed: 01/14/2023]
Abstract
AIMS/HYPOTHESIS We previously identified the G6PC2 locus as a strong determinant of fasting plasma glucose (FPG) and showed that a common G6PC2 intronic single nucleotide polymorphism (SNP) (rs560887) and two common G6PC2 promoter SNPs (rs573225 and rs13431652) are highly associated with FPG. However, these promoter SNPs have complex effects on G6PC2 fusion gene expression, and our data suggested that only rs13431652 is a potentially causative SNP. Here we examine the effect of rs560887 on G6PC2 pre-mRNA splicing and the contribution of an additional common G6PC2 promoter SNP, rs2232316, to the association signal. METHODS Minigene analyses were used to characterise the effect of rs560887 on G6PC2 pre-mRNA splicing. Fusion gene and gel retardation analyses characterised the effect of rs2232316 on G6PC2 promoter activity and transcription factor binding. The genetic association of rs2232316 with FPG variation was assessed using regression adjusted for age, sex and BMI in 4,220 Europeans with normal FPG. RESULTS The rs560887-G allele was shown to enhance G6PC2 pre-mRNA splicing, whereas the rs2232316-A allele enhanced G6PC2 transcription by promoting Foxa2 binding. Genetic analyses provide evidence for association of the rs2232316-A allele with increased FPG (β = 0.04 mmol/l; p = 4.3 × 10(-3)) as part of the same signal as rs560887, rs573225 and rs13431652. CONCLUSIONS/INTERPRETATION As with rs13431652, the in situ functional data with rs560887 and rs2232316 are in accord with the putative function of G6PC2 in pancreatic islets, and suggest that all three are potentially causative SNPs that contribute to the association between G6PC2 and FPG.
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Affiliation(s)
- D. A. Baerenwald
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 37232 Nashville, Tennessee, USA
| | - A. Bonnefond
- CNRS-UMR-8199, Institut Pasteur de Lille, F-59019, Lille, France
- University Lille Nord de France, F-59019 Lille, France
| | - N. Bouatia-Naji
- CNRS-UMR-8199, Institut Pasteur de Lille, F-59019, Lille, France
- University Lille Nord de France, F-59019 Lille, France
- INSERM U970, Paris Cardiovascular Research Center PARCC, 56 rue Leblanc, F-75015 Paris, France
| | - B. P. Flemming
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 37232 Nashville, Tennessee, USA
| | - O. C. Umunakwe
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 37232 Nashville, Tennessee, USA
| | - J. K. Oeser
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 37232 Nashville, Tennessee, USA
| | - L. D. Pound
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 37232 Nashville, Tennessee, USA
| | - N. L. Conley
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 37232 Nashville, Tennessee, USA
| | - S. Cauchi
- CNRS-UMR-8199, Institut Pasteur de Lille, F-59019, Lille, France
- University Lille Nord de France, F-59019 Lille, France
| | - S. Lobbens
- CNRS-UMR-8199, Institut Pasteur de Lille, F-59019, Lille, France
- University Lille Nord de France, F-59019 Lille, France
| | - E. Eury
- CNRS-UMR-8199, Institut Pasteur de Lille, F-59019, Lille, France
- University Lille Nord de France, F-59019 Lille, France
| | - B. Balkau
- INSERM, Centre for research in Epidemiology and Population Health (CESP), U1018, Epidemiology of diabetes, obesity and chronic renal disease over the lifecourse, F-94807, Villejuif, France
- Université Paris-Sud 11, UMRS 1018, F-94807 Villejuif, France
| | - O. Lantieri
- Institut inter-régional pour la santé (IRSA), F-37521 La Riche, France
| | - MAGIC Investigators
- Meta-Analysis of Glucose and Insulin related traits Consortium Investigators (http://www.magicinvestigators.org/)
| | - P. K. Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 37232 Nashville, Tennessee, USA
| | - D. A. Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 37232 Nashville, Tennessee, USA
| | - P. Froguel
- CNRS-UMR-8199, Institut Pasteur de Lille, F-59019, Lille, France
- University Lille Nord de France, F-59019 Lille, France
- Department of Genomics of Common Disease, School of Public Health, Imperial College London, W12 0NN London, UK
| | - R. M. O’Brien
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 37232 Nashville, Tennessee, USA
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A cytoprotective perspective on longevity regulation. Trends Cell Biol 2013; 23:409-20. [PMID: 23726168 DOI: 10.1016/j.tcb.2013.04.007] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/17/2013] [Accepted: 04/18/2013] [Indexed: 02/07/2023]
Abstract
There are many mechanisms of lifespan extension, including the disruption of insulin/insulin-like growth factor 1 (IGF-1) signaling, metabolism, translation, and feeding. Despite the disparate functions of these pathways, inhibition of each induces responses that buffer stress and damage. Here, emphasizing data from genetic analyses in Caenorhabditis elegans, we explore the effectors and upstream regulatory components of numerous cytoprotective mechanisms activated as major elements of longevity programs, including detoxification, innate immunity, proteostasis, and oxidative stress response. We show that their induction underpins longevity extension across functionally diverse triggers and across species. Intertwined with the evolution of longevity, cytoprotective pathways are coupled to the surveillance of core cellular components, with important implications in normal and aberrant responses to drugs, chemicals, and pathogens.
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Fraczek J, Bolleyn J, Vanhaecke T, Rogiers V, Vinken M. Primary hepatocyte cultures for pharmaco-toxicological studies: at the busy crossroad of various anti-dedifferentiation strategies. Arch Toxicol 2012; 87:577-610. [PMID: 23242478 DOI: 10.1007/s00204-012-0983-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 11/19/2012] [Indexed: 01/24/2023]
Abstract
Continuously increasing understanding of the molecular triggers responsible for the onset of diseases, paralleled by an equally dynamic evolution of chemical synthesis and screening methods, offers an abundance of pharmacological agents with a potential to become new successful drugs. However, before patients can benefit of newly developed pharmaceuticals, stringent safety filters need to be applied to weed out unfavourable drug candidates. Cost effectiveness and the need to identify compound liabilities, without exposing humans to unnecessary risks, has stimulated the shift of the safety studies to the earliest stages of drug discovery and development. In this regard, in vivo relevant organotypic in vitro models have high potential to revolutionize the preclinical safety testing. They can enable automation of the process, to match the requirements of high-throughput screening approaches, while satisfying ethical considerations. Cultures of primary hepatocytes became already an inherent part of the preclinical pharmaco-toxicological testing battery, yet their routine use, particularly for long-term assays, is limited by the progressive deterioration of liver-specific features. The availability of suitable hepatic and other organ-specific in vitro models is, however, of paramount importance in the light of changing European legal regulations in the field of chemical compounds of different origin, which gradually restrict the use of animal studies for safety assessment, as currently witnessed in cosmetic industry. Fortunately, research groups worldwide spare no effort to establish hepatic in vitro systems. In the present review, both classical and innovative methodologies to stabilize the in vivo-like hepatocyte phenotype in culture of primary hepatocytes are presented and discussed.
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Affiliation(s)
- J Fraczek
- Department of Toxicology, Faculty of Medicine and Pharmacy, Centre for Pharmaceutical Research, Vrije Universiteit Brussel, Belgium.
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24
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Fang Q, Chen S, Wang Y, Jiang S, Zhang R, Hu C, Wang C, Liu F, Xiang K, Jia W. Functional analyses of the mutation nt-128 T→G in the hepatocyte nuclear factor-1α promoter region in Chinese diabetes pedigrees. Diabet Med 2012; 29:1456-64. [PMID: 22413961 PMCID: PMC3570122 DOI: 10.1111/j.1464-5491.2012.03626.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS Hepatocyte nuclear factor-1α (HNF-1α) regulates the expression of genes encoding proteins involved in glucose metabolism and insulin secretion. Mutations in the HNF-1α gene cause maturity-onset diabetes of the young Type 3. However, the mechanism leading to this disease has not been completely ascertained. Previously, we found a novel mutation in the regulatory element of the human HNF-1α gene in two Chinese diabetes pedigrees. The nucleotide at position -128 T was substituted by G (nt-128 T→G). In this study, we analysed the functional defect of nt-128 T→G in HNF-1α transcription activity. METHODS Luciferase reporter gene assays were carried out to examine the functional characteristics of this mutant. Electrophoretic mobility shift assays and chromatin immunoprecipitation were performed to confirm the binding of nuclear proteins to oligonucleotides. RESULTS The variant construct (nt-128 T→G) had a 1.65-fold increase in promoter activity compared with that of the wild-type construct in HepG2 cells and a 1.33-fold increase in MIN6 cells, respectively. The variant resided at a FOXA/HNF-3 binding site identified by a series of competitive electrophoretic mobility shift assays and antibody supershift analyses. The assays showed a differential binding affinity in the wild-type and the nt-128 T→G mutant fragments by FOXA/HNF-3. Chromatin immunoprecipitation indicated that FOXA/HNF-3 bound to this region in vivo. One nucleotide substitution in the FOXA/HNF-3 site in the human HNF-1α regulatory element caused an increase of HNF-1α transcriptional activity. CONCLUSIONS Our data suggested that this substitution in the promoter region affects DNA-protein interaction and HNF-1α gene transcription. The mutant may contribute to the development of diabetes in these two nt-128 T→G pedigrees of Chinese.
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Affiliation(s)
- Q Fang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
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Regulation of the FABP7 gene by PAX6 in malignant glioma cells. Biochem Biophys Res Commun 2012; 422:482-7. [PMID: 22583899 DOI: 10.1016/j.bbrc.2012.05.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 05/04/2012] [Indexed: 01/01/2023]
Abstract
Brain fatty acid-binding protein (FABP7) and PAX6 are both expressed in radial glial cells and have been implicated in neurogenesis and glial cell differentiation. FABP7 and PAX6 have also been postulated to play a role in malignant glioma cell growth and invasion. Here, we address the role of PAX6 in regulating FABP7 gene expression in malignant glioma cells. We report that PAX6 and FABP7 RNA are generally co-expressed in malignant glioma cell lines, tumors and tumor neurospheres. Using the CAT reporter gene assay, we show that FABP7 promoter activity is upregulated by PAX6. Sequential deletion analysis of the FABP7 promoter, combined with gel shift and supershift assays demonstrate the presence of a PAX6 responsive region located upstream of the FABP7 gene, at -862 to -1033 bp. Inclusion of sequences between -1.2 and -1.8 kb reduced CAT activity, suggesting the presence of a repressor element within this region. While PAX6 overexpression did not induce endogenous FABP7 expression in FABP7-negative cells, knock-down of PAX6 in PAX6-positive malignant glioma cells resulted in reduced FABP7 levels. These data provide the first evidence of direct transactivation of the FABP7 proximal promoter by PAX6 and suggest a synergistic mechanism for PAX6 and other co-factor(s) in regulating FABP7 expression in malignant glioma.
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Liu RZ, Graham K, Glubrecht DD, Lai R, Mackey JR, Godbout R. A fatty acid-binding protein 7/RXRβ pathway enhances survival and proliferation in triple-negative breast cancer. J Pathol 2012; 228:310-21. [DOI: 10.1002/path.4001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 01/18/2012] [Accepted: 01/29/2012] [Indexed: 01/01/2023]
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FOXA1: a transcription factor with parallel functions in development and cancer. Biosci Rep 2012; 32:113-30. [PMID: 22115363 DOI: 10.1042/bsr20110046] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
When aberrant, factors critical for organ morphogenesis are also commonly involved in disease progression. FOXA1 (forkhead box A1), also known as HNF3α (hepatocyte nuclear factor 3α), is required for postnatal survival due to its essential role in controlling pancreatic and renal function. In addition to regulating a variety of tissues during embryogenesis and early life, rescue experiments have revealed a specific role for FOXA1 in the postnatal development of the mammary gland and prostate. Activity of the nuclear hormone receptors ERα (oestrogen receptor α) and AR (androgen receptor) is also required for proper development of the mammary gland and prostate respectively. FOXA1 modulates ER and AR function in breast and prostate cancer cells, supporting the postulate that FOXA1 is involved in ER and AR signalling under normal conditions, and that some carcinogenic processes in these tissues stem from hormonally regulated developmental pathways gone awry. In addition to broadly reviewing the function of FOXA1 in various aspects of development and cancer, this review focuses on the interplay of FOXA1/ER and FOXA1/AR, in normal and cancerous mammary and prostate epithelial cells. Given the hormone dependency of both breast and prostate cancer, a thorough understanding of FOXA1's role in both cancer types is critical for battling hormone receptor-positive disease and acquired anti-hormone resistance.
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Yokoyama Y, Iguchi K, Usui S, Hirano K. AMP-activated protein kinase modulates the gene expression of aquaporin 9 via forkhead box a2. Arch Biochem Biophys 2011; 515:80-8. [PMID: 21867676 DOI: 10.1016/j.abb.2011.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 08/05/2011] [Accepted: 08/06/2011] [Indexed: 11/29/2022]
Abstract
Aquaporin 9 (AQP9) is permeable to glycerol, which is a source material in lipogenesis and gluconeogenesis in the liver. We investigated the transcriptional regulation of the AQP9 gene by AMP-activated protein kinase (AMPK), known as an energy sensor in cells since AMPK contributes to the metabolism of carbohydrate, lipid, and protein by regulating the expression of many enzymes and transcription factors in metabolic pathways. An AMPK activator, 5-aminoimidazole-4-carboxamide-1-β-d-ribonucleoside (AICAR), was observed to suppress the expression of the AQP9 gene in HepG2 cells by promoting the phosphorylation of AMPK and AKT/PKB. Forkhead box a2 (Foxa2) was speculated to be one of the transcriptional regulators of AQP9 gene expression repressed by AICAR from the results of a reporter gene assay with a plasmid containing the promoter region of the AQP9 gene and knock-down of the Foxa2 gene by a specific siRNA. AICAR was determined to induce the phosphorylation and nuclear exclusion of Foxa2. Leptomycin B, inhibiting the binding of the nuclear exclusion signal sequence and chromosome region maintenance 1, prevented nuclear export of Foxa2 triggered by AICAR. These results suggest that the activated AMPK by AICAR causes suppression of the gene expression of AQP9 through transcriptional regulation by Foxa2.
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Affiliation(s)
- Yuichi Yokoyama
- Laboratory of Pharmaceutics, Department of Medical Pharmaceutics, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, Japan
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Hsieh CW, Huang C, Bederman I, Yang J, Beidelschies M, Hatzoglou M, Puchowicz M, Croniger CM. Function of phosphoenolpyruvate carboxykinase in mammary gland epithelial cells. J Lipid Res 2011; 52:1352-62. [PMID: 21504969 DOI: 10.1194/jlr.m012666] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previously, we have shown that Pck1 expression in mammary gland adipocytes and white adipose tissue maintains triglyceride stores through glyceroneogenesis, and these lipids were used for synthesis of milk triglycerides during lactation. Reduced milk triglycerides during lactation resulted in patterning of the newborn for insulin resistance. In this study, the role of Pck1 in mammary gland epithelial cells was analyzed. The developmental expression of Pck1 decreased in isolated mouse mammary gland epithelial cells through development and during lactation. Using HC11, a clonal mammary epithelial cell line, we found that both Janus kinase 2 signal transducers and activators of transcription 5 and the AKT pathways contributed to the repression of Pck1 mRNA by prolactin. These pathways necessitate three accessory factor regions of the Pck1 promoter for repression by prolactin. Using [U-(13)C(6)]glucose, [U-(13)C(3)]pyruvate, and [U-(13)C(3)]glycerol in HC11 cells, we determined that Pck1 functions in the pathway for the conversion of gluconeogenic precursors to glucose and contributes to glycerol-3-phosphate synthesis through glyceroneogenesis. Therefore, Pck1 plays an important role in both the mammary gland adipocytes and epithelial cells during lactation.
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Affiliation(s)
- Chang-Wen Hsieh
- Department of Nutrition, Case Western Reserve University, Cleveland, OH 44106, USA
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30
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Bouatia-Naji N, Bonnefond A, Baerenwald DA, Marchand M, Bugliani M, Marchetti P, Pattou F, Printz RL, Flemming BP, Umunakwe OC, Conley NL, Vaxillaire M, Lantieri O, Balkau B, Marre M, Lévy-Marchal C, Elliott P, Jarvelin MR, Meyre D, Dina C, Oeser JK, Froguel P, O'Brien RM. Genetic and functional assessment of the role of the rs13431652-A and rs573225-A alleles in the G6PC2 promoter that are strongly associated with elevated fasting glucose levels. Diabetes 2010; 59:2662-71. [PMID: 20622168 PMCID: PMC3279535 DOI: 10.2337/db10-0389] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Genome-wide association studies have identified a single nucleotide polymorphism (SNP), rs560887, located in a G6PC2 intron that is highly correlated with variations in fasting plasma glucose (FPG). G6PC2 encodes an islet-specific glucose-6-phosphatase catalytic subunit. This study examines the contribution of two G6PC2 promoter SNPs, rs13431652 and rs573225, to the association signal. RESEARCH DESIGN AND METHODS We genotyped 9,532 normal FPG participants (FPG <6.1 mmol/l) for three G6PC2 SNPs, rs13431652 (distal promoter), rs573225 (proximal promoter), rs560887 (3rd intron). We used regression analyses adjusted for age, sex, and BMI to assess the association with FPG and haplotype analyses to assess comparative SNP contributions. Fusion gene and gel retardation analyses characterized the effect of rs13431652 and rs573225 on G6PC2 promoter activity and transcription factor binding. RESULTS Genetic analyses provide evidence for a strong contribution of the promoter SNPs to FPG variability at the G6PC2 locus (rs13431652: β = 0.075, P = 3.6 × 10(-35); rs573225 β = 0.073 P = 3.6 × 10(-34)), in addition to rs560887 (β = 0.071, P = 1.2 × 10(-31)). The rs13431652-A and rs573225-A alleles promote increased NF-Y and Foxa2 binding, respectively. The rs13431652-A allele is associated with increased FPG and elevated promoter activity, consistent with the function of G6PC2 in pancreatic islets. In contrast, the rs573225-A allele is associated with elevated FPG but reduced promoter activity. CONCLUSIONS Genetic and in situ functional data support a potential role for rs13431652, but not rs573225, as a causative SNP linking G6PC2 to variations in FPG, though a causative role for rs573225 in vivo cannot be ruled out.
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Affiliation(s)
- Nabila Bouatia-Naji
- CNRS-UMR-8199, Institut Pasteur de Lille, Lille, France
- University Lille Nord de France, Lille, France
| | - Amélie Bonnefond
- CNRS-UMR-8199, Institut Pasteur de Lille, Lille, France
- University Lille Nord de France, Lille, France
| | - Devin A. Baerenwald
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Marion Marchand
- CNRS-UMR-8199, Institut Pasteur de Lille, Lille, France
- University Lille Nord de France, Lille, France
| | - Marco Bugliani
- Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - Piero Marchetti
- Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - François Pattou
- INSERM U859, Université de Lille-Nord de France, Centre Hospitalier Regional et Universitaire de Lille, Lille, France
| | - Richard L. Printz
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Brian P. Flemming
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Obi C. Umunakwe
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Nicholas L. Conley
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Martine Vaxillaire
- CNRS-UMR-8199, Institut Pasteur de Lille, Lille, France
- University Lille Nord de France, Lille, France
| | | | | | - Michel Marre
- Department of Endocrinology, Diabetology and Nutrition, Bichat-Claude Bernard University Hospital, Assistance Publique des Hôpitaux de Paris, Paris, France; INSERM U695, Université Paris 7, Paris, France
| | - Claire Lévy-Marchal
- INSERM U690, Robert Debré Hospital, Paris; Paris Diderot University, Paris, France
| | - Paul Elliott
- Department of Epidemiology and Public Health, Imperial College London, London, U.K
| | - Marjo-Riitta Jarvelin
- Department of Epidemiology and Public Health, Imperial College London, London, U.K
- Institute of Health Sciences, University of Oulu, Department of Child and Adolescent Health, National Public Health Institute, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - David Meyre
- CNRS-UMR-8199, Institut Pasteur de Lille, Lille, France
- University Lille Nord de France, Lille, France
| | - Christian Dina
- CNRS-UMR-8199, Institut Pasteur de Lille, Lille, France
- University Lille Nord de France, Lille, France
| | - James K. Oeser
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Philippe Froguel
- CNRS-UMR-8199, Institut Pasteur de Lille, Lille, France
- University Lille Nord de France, Lille, France
- Department of Genomics of Common Disease, School of Public Health, Imperial College London, London, U.K
| | - Richard M. O'Brien
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
- Corresponding author: Richard M. O'Brien,
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Kaestner KH. The FoxA factors in organogenesis and differentiation. Curr Opin Genet Dev 2010; 20:527-32. [PMID: 20591647 DOI: 10.1016/j.gde.2010.06.005] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 06/01/2010] [Accepted: 06/02/2010] [Indexed: 11/26/2022]
Abstract
The genetic analysis of the Foxa genes in both total and conditional mutant mice has clearly established that organogenesis of multiple systems is controlled by this subfamily of winged helix transcription factors. These discoveries followed the establishment of the conceptional framework of the mechanism of action of the FoxA proteins as 'pioneer factors' that can engage chromatin before other transcription factors. Recent molecular and genomic studies have also shown that FoxA proteins can facilitate binding of several nuclear receptors to their respective targets in a context-dependent manner, greatly increasing the range and importance of FoxA factors in biology.
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Affiliation(s)
- Klaus H Kaestner
- Department of Genetics & Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6145, United States.
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32
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Mohler ML, He Y, Wu Z, Hong SS, Miller DD. Dissociated non-steroidal glucocorticoids: tuning out untoward effects. Expert Opin Ther Pat 2010; 17:37-58. [PMID: 20144062 DOI: 10.1517/13543776.17.1.37] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The endogenous glucocorticoid (GC), cortisol, is involved in maintaining homeostatic balance in glucose regulation and immune response while allowing stress adaptation. The glucocorticoid receptor (GR) is required to maintain life and is the target of numerous FDA-approved drugs. Synthetic steroidal GCs are useful in a plethora of conditions characterized by excessive inflammatory or immune responses. Unfortunately, the GCs used at present have potentially dose-limiting and debilitating side effects, some of which derive from the glucose regulatory role of GCs. Consequently, there is a great need to find agents which preserve the potent immune effects without the side effects. This manuscript reviews the existing patent literature on these intensely sought non-steroidal agents that dissociate the therapeutic from metabolic effects, or specifically retain certain GR target effects with attenuated untoward effects. The chemical classes and underlying mechanisms (when known) for these non-steroidal GCs are discussed.
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Affiliation(s)
- Michael L Mohler
- GTx, Inc. - The Men's Health Biotech, 3 North Dunlap Street, Memphis, TN 38163, USA
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33
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Gebhardt R, Hovhannisyan A. Organ patterning in the adult stage: the role of Wnt/beta-catenin signaling in liver zonation and beyond. Dev Dyn 2010; 239:45-55. [PMID: 19705440 DOI: 10.1002/dvdy.22041] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Wnt/beta-catenin signaling has been found to play key roles in metabolic zonation of adult liver, regeneration, and hepatocellular carcinogenesis. In this review, recent progress in this field is summarized, in particular the rapidly growing knowledge about the various interactions of beta-catenin with many transcription factors involved in controlling metabolism. These interactions may provide the basis for understanding how the wide range of activities of Wnt/beta-catenin signaling is differentially interpreted. Based on these results, a three-level mode for the molecular interpretation of beta-catenin activity gradients in liver is proposed favoring cell differentiation, metabolic zonation, and proliferation. While derangement of the combinatorial interplay of the various transcription factors with beta-catenin at the intermediary activity level may contribute to the development of metabolic diseases, extremely high activation of beta-catenin may eventually lead to initiation and progression of hepatocellular tumors.
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Affiliation(s)
- Rolf Gebhardt
- Institute of Biochemistry, Medical Faculty, University of Leipzig, Leipzig, Germany.
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Le Lay J, Kaestner KH. The Fox genes in the liver: from organogenesis to functional integration. Physiol Rev 2010; 90:1-22. [PMID: 20086072 DOI: 10.1152/physrev.00018.2009] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Formation and function of the liver are highly controlled, essential processes. Multiple signaling pathways and transcriptional regulatory networks cooperate in this complex system. The evolutionarily conserved FOX, for Forkhead bOX, class of transcriptional regulators is critical to many aspects of liver development and function. The FOX proteins are small, mostly monomeric DNA binding factors containing the so-called winged helix DNA binding motif that distinguishes them from other classes of transcription factors. We discuss the biochemical and genetic roles of Foxa, Foxl1, Foxm1, and Foxo, as these have been shown to regulate many processes throughout the life of the organ, controlling both formation and function of the liver.
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Affiliation(s)
- John Le Lay
- Department of Genetics and Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6145, USA
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35
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Huang WT, Weng CF. Roles of hepatocyte nuclear factors (HNF) in the regulation of reproduction in teleosts. JOURNAL OF FISH BIOLOGY 2010; 76:225-239. [PMID: 20738706 DOI: 10.1111/j.1095-8649.2009.02480.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Hepatocyte nuclear factor (HNF) families are composed of liver-enriched transcription factors and upstream regulators of many liver-specific genes. HNF are involved in liver-specific gene expression, metabolism, development, cell growth and many cellular functions in the body. HNF genes can be activated or influenced by several hormones and insulin-like growth factors (IGF), and different combinations of the four HNF factors form a network in controlling the expression of liver-specific or liver-enriched genes. The functions of these factors and their interactions within the gonads of bony fishes, however, are not well understood, and the related literature is scant. Recently, several members of the HNF families have been detected in teleost gonads together with their downstream genes (IGF-I and IGF-II), suggesting that these HNF could be upregulated in vitro by steroid hormones. Thus, the hormone-HNF-IGF-gonad interaction may be an alternative axis in the reproductive mechanism that acts in concert with the conventional hypothalamus-pituitary-gonad pathway. This may help the early development and maturation of the gonad or gamete, sexual maturity or reversion and spawning-regulating mechanisms among fishes to be understood.
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Affiliation(s)
- W-T Huang
- Department of Molecular Biotechnology, Da-Yeh University, Chang-Hua 515, Taiwan
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Sun Q, Yu X, Degraff DJ, Matusik RJ. Upstream stimulatory factor 2, a novel FoxA1-interacting protein, is involved in prostate-specific gene expression. Mol Endocrinol 2009; 23:2038-47. [PMID: 19846536 DOI: 10.1210/me.2009-0092] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The forkhead protein A1 (FoxA1) is critical for the androgenic regulation of prostate-specific promoters. Prostate tissue rescued from FoxA1 knockout mice exhibits abnormal prostate development, typified by the absence of expression of differentiation markers and inability to engage in secretion. Chromatin immunoprecipitation and coimmunoprecipitation studies revealed that FoxA1 is one of the earliest transcription factors that binds to prostate-specific promoters, and that a direct protein-protein interaction occurs between FoxA1 and androgen receptor. Interestingly, evidence of the interaction of FoxA1 with other transcription factors is lacking. The upstream stimulatory factor 2 (USF2), an E-box-binding transcription factor of the basic-helix-loop-helix-leucine-zipper family, binds to a consensus DNA sequence similar to FoxA1. Our in vitro and in vivo studies demonstrate the binding of USF2 to prostate-specific gene promoters including the probasin promoter, spermine-binding protein promoter, and prostate-specific antigen core enhancer. Furthermore, we show a direct physical interaction between FoxA1 and USF2 through the use of immunoprecipitation and glutathione-S-transferase pull-down assays. This interaction is mediated via the forkhead DNA-binding domain of FoxA1 and the DNA-binding domain of USF2. In summary, these data indicate that USF2 is one of the components of the FoxA1/androgen receptor transcriptional protein complex that contributes to the expression of androgen-regulated and prostate-specific genes.
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Affiliation(s)
- Qian Sun
- Department of Cancer Biology, The Vanderbilt Prostate Cancer Center, Vanderbilt University, Nashville, Tennessee 37232, USA.
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Pandey AK, Bhardwaj V, Datta M. Tumour necrosis factor-alpha attenuates insulin action on phosphoenolpyruvate carboxykinase gene expression and gluconeogenesis by altering the cellular localization of Foxa2 in HepG2 cells. FEBS J 2009; 276:3757-69. [PMID: 19769745 DOI: 10.1111/j.1742-4658.2009.07091.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Circulating tumour necrosis factor-alpha (TNFalpha) levels, which are elevated in obesity-associated insulin resistance and diabetes, inhibit insulin signalling at several points in the signalling cascade. The liver is critical in maintaining circulating glucose levels and, in a preliminary investigation using the human hepatoma (HepG2) cell line in this study, we demonstrated the role of TNFalpha in the regulation of this phenomenon and determined the underlying molecular mechanisms. As the transcription factor Foxa2 has been implicated, in part, in the regulation of gluconeogenic genes, we studied the effects of TNFalpha and/or insulin on its cellular status in hepatocytes, followed by an assessment of its occupancy on the phosphoenolpyruvate carboxykinase (PEPCK) promoter. Preincubation of cells with TNFalpha, followed by insulin, significantly prevented insulin-mediated nuclear exclusion of Foxa2 and substantially increased its nuclear concentration. Foxa2 was subsequently found to occupy its binding element on the PEPCK promoter. TNFalpha alone, however, did not alter the status of cellular Foxa2 or its occupancy on the PEPCK promoter. TNFalpha preincubation also significantly attenuated insulin-induced inhibition of the expression of gluconeogenic enzymes and hepatic glucose production. Insulin inhibition of PEPCK expression and the preventive effect of TNFalpha could be partially but significantly restored in the presence of Foxa2 siRNA. Several other well-known mediators of insulin action in the liver in general and of gluconeogenic genes in particular include Foxo1, PGC-1 and SREBP-1c. Our results indicate that another transcription factor, Foxa2, is at least partly responsible for the attenuating effect of TNFalpha on insulin action on PEPCK expression and glucose production in HepG2 cells.
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Affiliation(s)
- Amit K Pandey
- Institute of Genomics and Integrative Biology (CSIR), Delhi, India
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Fasting hyperglycemia is not associated with increased expression of PEPCK or G6Pc in patients with Type 2 Diabetes. Proc Natl Acad Sci U S A 2009; 106:12121-6. [PMID: 19587243 DOI: 10.1073/pnas.0812547106] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Fasting hyperglycemia in patients with type 2 diabetes mellitus (T2DM) is attributed to increased hepatic gluconeogenesis, which has been ascribed to increased transcriptional expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase, catalytic (G6Pc). To test this hypothesis, we examined hepatic expression of these 2 key gluconeogenic enzymes in 2 rodent models of fasting hyperglycemia and in patients with T2DM. In rats, high-fat feeding (HFF) induces insulin resistance but a robust beta-cell response prevents hyperglycemia. Fasting hyperglycemia was induced in the first rat model by using nicotinamide and streptozotocin to prevent beta-cell compensation, in combination with HFF (STZ/HFF). In a second model, control and HFF rats were infused with somatostatin, followed by portal vein infusion of insulin and glucagon. Finally, the expression of these enzymes was measured in liver biopsy samples obtained from insulin sensitive, insulin resistant, and untreated T2DM patients undergoing bariatric surgery. Rats treated with STZ/HFF developed modest fasting hyperglycemia (119 +/- 4 vs. 153 +/- 6 mg/dL, P < 0.001) and increased rates of endogenous glucose production (EGP) (4.6 +/- 0.6 vs. 6.9 +/- 0.6 mg/kg/min, P = 0.02). Surprisingly, the expression of PEPCK or G6Pc was not increased. Matching plasma insulin and glucagon with portal infusions led to higher plasma glucoses in the HFF rats (147 +/- 4 vs. 161 +/- 4 mg/dL, P = 0.05) with higher rates of EGP and gluconeogenesis. However, PEPCK and G6Pc expression remained unchanged. Finally, in patients with T2DM, hepatic expression of PEPCK or G6Pc was not increased. Thus, in contrast to current dogma, these data demonstrate that increased transcriptional expression of PEPCK1 and G6Pc does not account for increased gluconeogenesis and fasting hyperglycemia in patients with T2DM.
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Brun M, Coles JE, Monckton EA, Glubrecht DD, Bisgrove D, Godbout R. Nuclear factor I regulates brain fatty acid-binding protein and glial fibrillary acidic protein gene expression in malignant glioma cell lines. J Mol Biol 2009; 391:282-300. [PMID: 19540848 DOI: 10.1016/j.jmb.2009.06.041] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 06/10/2009] [Accepted: 06/15/2009] [Indexed: 10/20/2022]
Abstract
Glial fibrillary acidic protein (GFAP), an intermediate filament protein normally found in astrocytes, and the radial glial marker brain fatty acid-binding protein (B-FABP; also known as FABP7) are co-expressed in malignant glioma cell lines and tumors. Nuclear factor I (NFI) recognition sites have been identified in the B-FABP and GFAP promoters, and transcription of both genes is believed to be regulated by NFI. Here, we study the role of the different members of the NFI family in regulating endogenous and ectopic B-FABP and GFAP gene transcription in human malignant glioma cells. We show by gel shifts that all four members of the NFI family (NFIA, NFIB, NFIC, and NFIX) bind to B-FABP and GFAP NFI consensus sites. Over-expression of NFIs, in conjunction with mutation analysis of NFI consensus sites using a reporter gene assay, supports a role for all four NFIs in the regulation of the GFAP and B-FABP genes. Knock-down of single or combined NFIs reveals promoter-dependent and promoter-context-dependent interaction patterns and suggests cross talk between the different members of the NFI family. Our data indicate that the NFI family of transcription factors plays a key role in the regulation of both the B-FABP and GFAP genes in malignant glioma cells.
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Affiliation(s)
- Miranda Brun
- Department of Oncology, Cross Cancer Institute, University of Alberta, Alberta, Canada
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Hannenhalli S, Kaestner KH. The evolution of Fox genes and their role in development and disease. Nat Rev Genet 2009; 10:233-40. [PMID: 19274050 DOI: 10.1038/nrg2523] [Citation(s) in RCA: 484] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The forkhead box (Fox) family of transcription factors, which originated in unicellular eukaryotes, has expanded over time through multiple duplication events, and sometimes through gene loss, to over 40 members in mammals. Fox genes have evolved to acquire a specialized function in many key biological processes. Mutations in Fox genes have a profound effect on human disease, causing phenotypes as varied as cancer, glaucoma and language disorders. We summarize the salient features of the evolution of the Fox gene family and highlight the diverse contribution of various Fox subfamilies to developmental processes, from organogenesis to speech acquisition.
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Affiliation(s)
- Sridhar Hannenhalli
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA. ;
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Onuma H, Oeser JK, Nelson BA, Wang Y, Flemming BP, Scheving LA, Russell WE, O'Brien RM. Insulin and epidermal growth factor suppress basal glucose-6-phosphatase catalytic subunit gene transcription through overlapping but distinct mechanisms. Biochem J 2009; 417:611-20. [PMID: 18847435 PMCID: PMC2929524 DOI: 10.1042/bj20080999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The G6Pase (glucose-6-phosphatase catalytic subunit) catalyses the final step in the gluconeogenic and glycogenolytic pathways, the hydrolysis of glucose-6-phosphate to glucose. We show here that, in HepG2 hepatoma cells, EGF (epidermal growth factor) inhibits basal mouse G6Pase fusion gene transcription. Several studies have shown that insulin represses basal mouse G6Pase fusion gene transcription through FOXO1 (forkhead box O1), but Stoffel and colleagues have recently suggested that insulin can also regulate gene transcription through FOXA2 (forkhead box A2) [Wolfrum, Asilmaz, Luca, Friedman and Stoffel (2003) Proc. Natl. Acad. Sci. 100, 11624-11629]. A combined GR (glucocorticoid receptor)-FOXA2 binding site is located between -185 and -174 in the mouse G6Pase promoter overlapping two FOXO1 binding sites located between (-188 and -182) and (-174 and -168). Selective mutation of the FOXO1 binding sites reduced the effect of insulin, whereas mutation of the GR/FOXA2 binding site had no effect on the insulin response. In contrast, selective mutation of the FOXO1 and GR/FOXA2 binding sites both reduced the effect of EGF. The effect of these mutations was additive, since the combined mutation of both FOXO1 and GR/FOXA2 binding sites reduced the effect of EGF to a greater extent than the individual mutations. These results suggest that, in HepG2 cells, GR and/or FOXA2 are required for the inhibition of basal G6Pase gene transcription by EGF but not insulin. EGF also inhibits hepatic G6Pase gene expression in vivo, but in cultured hepatocytes EGF has the opposite effect of stimulating expression, an observation that may be explained by a switch in ErbB receptor sub-type expression following hepatocyte isolation.
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Affiliation(s)
- Hiroshi Onuma
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical School, Nashville, TN 37232, U.S.A
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Kamagate A, Qu S, Perdomo G, Su D, Kim DH, Slusher S, Meseck M, Dong HH. FoxO1 mediates insulin-dependent regulation of hepatic VLDL production in mice. J Clin Invest 2008. [PMID: 18497885 DOI: 10.1172/jci32914.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Excessive production of triglyceride-rich VLDL is attributable to hypertriglyceridemia. VLDL production is facilitated by microsomal triglyceride transfer protein (MTP) in a rate-limiting step that is regulated by insulin. To characterize the underlying mechanism, we studied hepatic MTP regulation by forkhead box O1 (FoxO1), a transcription factor that plays a key role in hepatic insulin signaling. In HepG2 cells, MTP expression was induced by FoxO1 and inhibited by exposure to insulin. This effect correlated with the ability of FoxO1 to bind and stimulate MTP promoter activity. Deletion or mutation of the FoxO1 target site within the MTP promoter disabled FoxO1 binding and resulted in abolition of insulin-dependent regulation of MTP expression. We generated mice that expressed a constitutively active FoxO1 transgene and found that increased FoxO1 activity was associated with enhanced MTP expression, augmented VLDL production, and elevated plasma triglyceride levels. In contrast, RNAi-mediated silencing of hepatic FoxO1 was associated with reduced MTP and VLDL production in adult mice. Furthermore, we found that hepatic FoxO1 abundance and MTP production were increased in mice with abnormal triglyceride metabolism. These data suggest that FoxO1 mediates insulin regulation of MTP production and that augmented MTP levels may be a causative factor for VLDL overproduction and hypertriglyceridemia in diabetes.
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Affiliation(s)
- Adama Kamagate
- Rangos Research Center, Children's Hospital of Pittsburgh, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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Kamagate A, Qu S, Perdomo G, Su D, Kim DH, Slusher S, Meseck M, Dong HH. FoxO1 mediates insulin-dependent regulation of hepatic VLDL production in mice. J Clin Invest 2008; 118:2347-64. [PMID: 18497885 DOI: 10.1172/jci32914] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2007] [Accepted: 04/16/2008] [Indexed: 01/10/2023] Open
Abstract
Excessive production of triglyceride-rich VLDL is attributable to hypertriglyceridemia. VLDL production is facilitated by microsomal triglyceride transfer protein (MTP) in a rate-limiting step that is regulated by insulin. To characterize the underlying mechanism, we studied hepatic MTP regulation by forkhead box O1 (FoxO1), a transcription factor that plays a key role in hepatic insulin signaling. In HepG2 cells, MTP expression was induced by FoxO1 and inhibited by exposure to insulin. This effect correlated with the ability of FoxO1 to bind and stimulate MTP promoter activity. Deletion or mutation of the FoxO1 target site within the MTP promoter disabled FoxO1 binding and resulted in abolition of insulin-dependent regulation of MTP expression. We generated mice that expressed a constitutively active FoxO1 transgene and found that increased FoxO1 activity was associated with enhanced MTP expression, augmented VLDL production, and elevated plasma triglyceride levels. In contrast, RNAi-mediated silencing of hepatic FoxO1 was associated with reduced MTP and VLDL production in adult mice. Furthermore, we found that hepatic FoxO1 abundance and MTP production were increased in mice with abnormal triglyceride metabolism. These data suggest that FoxO1 mediates insulin regulation of MTP production and that augmented MTP levels may be a causative factor for VLDL overproduction and hypertriglyceridemia in diabetes.
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Affiliation(s)
- Adama Kamagate
- Rangos Research Center, Children's Hospital of Pittsburgh, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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Wederell ED, Bilenky M, Cullum R, Thiessen N, Dagpinar M, Delaney A, Varhol R, Zhao Y, Zeng T, Bernier B, Ingham M, Hirst M, Robertson G, Marra MA, Jones S, Hoodless PA. Global analysis of in vivo Foxa2-binding sites in mouse adult liver using massively parallel sequencing. Nucleic Acids Res 2008; 36:4549-64. [PMID: 18611952 PMCID: PMC2504304 DOI: 10.1093/nar/gkn382] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Foxa2 (HNF3β) is a one of three, closely related transcription factors that are critical to the development and function of the mouse liver. We have used chromatin immunoprecipitation and massively parallel Illumina 1G sequencing (ChIP–Seq) to create a genome-wide profile of in vivo Foxa2-binding sites in the adult liver. More than 65% of the ∼11.5 k genomic sites associated with Foxa2 binding, mapped to extended gene regions of annotated genes, while more than 30% of intragenic sites were located within first introns. 20.5% of all sites were further than 50 kb from any annotated gene, suggesting an association with novel gene regions. QPCR analysis demonstrated a strong positive correlation between peak height and fold enrichment for Foxa2-binding sites. We measured the relationship between Foxa2 and liver gene expression by overlapping Foxa2-binding sites with a SAGE transcriptome profile, and found that 43.5% of genes expressed in the liver were also associated with Foxa2 binding. We also identified potential Foxa2-interacting transcription factors whose motifs were enriched near Foxa2-binding sites. Our comprehensive results for in vivo Foxa2-binding sites in the mouse liver will contribute to resolving transcriptional regulatory networks that are important for adult liver function.
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Higuchi S, Kubota M, Iguchi K, Usui S, Kiho T, Hirano K. Transcriptional regulation of aquaporin 3 by insulin. J Cell Biochem 2008; 102:1051-8. [PMID: 17471492 DOI: 10.1002/jcb.21350] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In the current study, we identified a regulatory factor for the transcription of aquaporin 3 (AQP3) whose expression is repressed by insulin. We constructed a luciferase reporter vector containing bp -1382 to -12 of the 5'-flanking region of the AQP3 gene for a reporter gene assay and observed that luciferase activity in transfectants with the plasmid decreased on treatment with insulin. Serial deletion constructs revealed two regions responsible for the insulin-mediated repression, one between bps -1382 and -780, and the other between bps -404 and -82. mRNA expression of forkhead box a2 (Foxa2), the binding site of which was located between bps -1382 and -780, was found to decrease on treatment with insulin. A mutant reporter plasmid with an altered Foxa2-binding site and siRNA for the Foxa2 sequence counteracted the insulin-mediated repression of AQP3 transcription. These results suggest that Foxa2 is one of the transcriptional regulators for AQP3 gene expression regulated by insulin.
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Affiliation(s)
- Shota Higuchi
- Department of Pharmaceutics, Gifu Pharmaceutical University, 5-6-1 Mitahorahigashi, Gifu 502-8585, Japan
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Abstract
The Forkhead family of transcription factors modulates a wide variety of cellular functions in cardiovascular tissues. In this review article, we discuss recent advances in our understanding of regulation provided by the forkhead factors in cardiac myocytes and vascular cells.
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Affiliation(s)
- Kyriakos N Papanicolaou
- Molecular Cardiology/Whitaker Cardiovascular Institute, Boston University School of Medicine, 715 Albany Street, W611, Boston, MA 02118, USA
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Huang WT, Yu HC, Hsu CC, Liao CF, Gong HY, Lin CJF, Wu JL, Weng CF. Steroid hormones (17β-estradiol and hydrocortisone) upregulate hepatocyte nuclear factor (HNF)-3β and insulin-like growth factors I and II expression in the gonads of tilapia (Oreochromis mossambicus) in vitro. Theriogenology 2007; 68:988-1002. [PMID: 17804049 DOI: 10.1016/j.theriogenology.2007.07.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 07/04/2007] [Indexed: 11/28/2022]
Abstract
Hepatocyte nuclear factors (HNF-1alpha, -1beta and -3beta) and insulin-like growth factors (IGF-I and -II), which are involved in liver-specific gene expression, metabolism, development and cell growth, have been found in the gonads of tilapia (Oreochromis mossambicus). However, the functions of these factors and how they interact within the gonads of bony fish are not understood. In the present study, we provided experimental evidence that the expression of HNF-3beta in the gonads of tilapia, but not HNF-1alpha and -1beta, was affected in vitro by 17beta-estradiol and hydrocortisone. Immunohistochemical staining confirmed that tilapia HNF-3beta was mainly found in the nuclei of hepatocytes, the follicular granulosa cells of the ovaries, and the interstitial cells of the testes of adult tilapia. Further data were gathered at various steroid concentrations (0.1, 1, 10, 100, and 1000 nM) over various culture intervals (6, 12, 18, 24, 30, and 36 h) and subjected to semi-quantitative RT-PCR analysis. The expression of downstream genes (IGF-I and -II) followed the same temporal patterns as HNF-3beta, albeit at decreased levels for 30 and 36 h culture intervals. Both hormones upregulated HNF-3beta mRNA expression at concentrations of 0.1-10 nM, and reached optimal physiological concentrations for induction of IGFs at 1-10 nM. The identity of the PCR fragments was concurrently verified by sequencing and PCR-Southern hybridization. We inferred that HNF-3beta and IGFs may play a regulatory role in tilapia gonads during oocyte maturation and spermatogenesis.
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Affiliation(s)
- Wei-Tung Huang
- Department of Molecular Biotechnology, Da-Yeh University, 515, Chang-Hua, Taiwan
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Vegiopoulos A, Herzig S. Glucocorticoids, metabolism and metabolic diseases. Mol Cell Endocrinol 2007; 275:43-61. [PMID: 17624658 DOI: 10.1016/j.mce.2007.05.015] [Citation(s) in RCA: 332] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 05/14/2007] [Accepted: 05/17/2007] [Indexed: 12/14/2022]
Abstract
Since the discovery of the beneficial effects of adrenocortical extracts for treating adrenal insufficiency more than 80 years ago, glucocorticoids (GC) and their cognate, intracellular receptor, the glucocorticoid receptor (GR) have been characterized as critical components of the delicate hormonal control system that determines energy homeostasis in mammals. Whereas physiological levels of GCs are required for proper metabolic control, excessive GC action has been tied to a variety of pandemic metabolic diseases, such as type II diabetes and obesity. Highlighted by its importance for human health, the investigation of molecular mechanisms of GC/GR action has become a major focus in biomedical research. In particular, the understanding of tissue-specific functions of the GC-GR pathway has been proven to be of substantial value for the identification of novel therapeutic options in the treatment of severe metabolic disorders. Therefore, this review focuses on the role of the GC-GR axis for metabolic homeostasis and dysregulation, emphasizing tissue-specific functions of GCs in the control of energy metabolism.
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Yang Y, Chen M, Loux TJ, Harmon CM. Regulation of FAT/CD36 mRNA gene expression by long chain fatty acids in the differentiated 3T3-L1 cells. Pediatr Surg Int 2007; 23:675-83. [PMID: 17516074 DOI: 10.1007/s00383-007-1942-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/13/2007] [Indexed: 11/27/2022]
Abstract
Defects in fatty acid translocase (FAT/CD36) have been identified as a major factor in insulin resistance and defective fatty acid and glucose metabolism. Therefore, understanding of the regulation of FAT/CD36 expression and function is important for a potential therapeutic target for type II diabetes. We differentiated 3T3-L1 preadipocytes into matured adipocytes and examined the roles of insulin and long chain fatty acids on FAT/CD36 expression and function. Our results indicate that FAT/CD36 mRNA expression was not detected at preadipocyte but was significantly increased at matured adipocyte. In fully differentiated 3T3-L1 adipocytes, insulin significantly increased FAT/CD36 mRNA and protein expression in a dose dependent manner. The free fatty acid stearic acid reduced FAT/CD36 mRNA expression while the non-metabolizable free fatty acid alpha-bromopalmitate (2-BP) significantly increased FAT/CD36 mRNA and protein expression. Isoproterenol, in contrast, dose-dependently reduced FAT/CD36 mRNA expression and increased free fatty acid release. Mechanism analysis indicated that the effect of insulin and 2-BP on the FAT/CD36 mRNA gene expression may be mediated through activation of PPAR-gamma, suggesting that FAT/CD36 may have important implications in the pathophysiology of defective fatty acid metabolism.
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Affiliation(s)
- Yingkui Yang
- Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35205, USA
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Behzad H, Jamil S, Denny TA, Duronio V. Cytokine-mediated FOXO3a phosphorylation suppresses FasL expression in hemopoietic cell lines: investigations of the role of Fas in apoptosis due to cytokine starvation. Cytokine 2007; 38:74-83. [PMID: 17604640 DOI: 10.1016/j.cyto.2007.05.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 01/31/2007] [Accepted: 05/08/2007] [Indexed: 11/26/2022]
Abstract
We have investigated phosphatidylinositol 3-kinase (PI3K)-dependent survival signalling pathways using several cytokines in three different hemopoietic cell lines, MC/9, FDC-P1, and TF-1. Cytokines caused PI3K- and PKB-dependent phosphorylation of FOXO3a (previously known as FKHRL1) at three distinct sites. Following cytokine withdrawal or PI3K inhibition, both of which are known to lead to apoptosis, there was a loss of FOXO3a phosphorylation, and a resulting increase in forkhead transcriptional activity, along with increased expression of Fas Ligand (FasL), which could be detected at the cell surface. Concurrently, an increase in cell surface expression of Fas was also detected. Despite the presence of both FasL and Fas, there was no detectable evidence that activation of Fas-mediated apoptotic events was contributing to apoptosis resulting from cytokine starvation or inhibition of PI3K activity. Thus, inhibition of FOXO3a activity is mediated by the PI3K-PKB pathway, but regulation of FasL is not the primary means by which cell survival is regulated in cytokine-dependent hemopoietic cells. We were also able to confirm increased expression of known FOXO3a targets, Bim and p27kip1. Together, these results support the conclusion that mitochondrial-mediated signals play the major role in apoptosis of hemopoietic cells due to loss of cytokine signalling.
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Affiliation(s)
- Hayedeh Behzad
- Department of Medicine, University of British Columbia and Vancouver Coastal Health Research Institute, Jack Bell Research Centre, 2660 Oak Street, Vancouver, BC, Canada V6H 3Z6
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