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Strous GJ, Almeida ADS, Putters J, Schantl J, Sedek M, Slotman JA, Nespital T, Hassink GC, Mol JA. Growth Hormone Receptor Regulation in Cancer and Chronic Diseases. Front Endocrinol (Lausanne) 2020; 11:597573. [PMID: 33312162 PMCID: PMC7708378 DOI: 10.3389/fendo.2020.597573] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/14/2020] [Indexed: 12/14/2022] Open
Abstract
The GHR signaling pathway plays important roles in growth, metabolism, cell cycle control, immunity, homeostatic processes, and chemoresistance via both the JAK/STAT and the SRC pathways. Dysregulation of GHR signaling is associated with various diseases and chronic conditions such as acromegaly, cancer, aging, metabolic disease, fibroses, inflammation and autoimmunity. Numerous studies entailing the GHR signaling pathway have been conducted for various cancers. Diverse factors mediate the up- or down-regulation of GHR signaling through post-translational modifications. Of the numerous modifications, ubiquitination and deubiquitination are prominent events. Ubiquitination by E3 ligase attaches ubiquitins to target proteins and induces proteasomal degradation or starts the sequence of events that leads to endocytosis and lysosomal degradation. In this review, we discuss the role of first line effectors that act directly on the GHR at the cell surface including ADAM17, JAK2, SRC family member Lyn, Ubc13/CHIP, proteasome, βTrCP, CK2, STAT5b, and SOCS2. Activity of all, except JAK2, Lyn and STAT5b, counteract GHR signaling. Loss of their function increases the GH-induced signaling in favor of aging and certain chronic diseases, exemplified by increased lung cancer risk in case of a mutation in the SOCS2-GHR interaction site. Insight in their roles in GHR signaling can be applied for cancer and other therapeutic strategies.
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Affiliation(s)
- Ger J. Strous
- Department of Cell Biology, Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, Netherlands
- BIMINI Biotech B.V., Leiden, Netherlands
| | - Ana Da Silva Almeida
- Department of Cell Biology, Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Joyce Putters
- Department of Cell Biology, Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Julia Schantl
- Department of Cell Biology, Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Magdalena Sedek
- Department of Cell Biology, Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Johan A. Slotman
- Department of Cell Biology, Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Tobias Nespital
- Department of Cell Biology, Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Gerco C. Hassink
- Department of Cell Biology, Centre for Molecular Medicine, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Jan A. Mol
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
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Della Torre S. Non-alcoholic Fatty Liver Disease as a Canonical Example of Metabolic Inflammatory-Based Liver Disease Showing a Sex-Specific Prevalence: Relevance of Estrogen Signaling. Front Endocrinol (Lausanne) 2020; 11:572490. [PMID: 33071979 PMCID: PMC7531579 DOI: 10.3389/fendo.2020.572490] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 08/20/2020] [Indexed: 12/11/2022] Open
Abstract
There is extensive evidence supporting the interplay between metabolism and immune response, that have evolved in close relationship, sharing regulatory molecules and signaling systems, to support biological functions. Nowadays, the disruption of this interaction in the context of obesity and overnutrition underlies the increasing incidence of many inflammatory-based metabolic diseases, even in a sex-specific fashion. During evolution, the interplay between metabolism and reproduction has reached a degree of complexity particularly high in female mammals, likely to ensure reproduction only under favorable conditions. Several factors may account for differences in the incidence and progression of inflammatory-based metabolic diseases between females and males, thus contributing to age-related disease development and difference in life expectancy between the two sexes. Among these factors, estrogens, acting mainly through Estrogen Receptors (ERs), have been reported to regulate several metabolic pathways and inflammatory processes particularly in the liver, the metabolic organ showing the highest degree of sexual dimorphism. This review aims to investigate on the interaction between metabolism and inflammation in the liver, focusing on the relevance of estrogen signaling in counteracting the development and progression of non-alcoholic fatty liver disease (NAFLD), a canonical example of metabolic inflammatory-based liver disease showing a sex-specific prevalence. Understanding the role of estrogens/ERs in the regulation of hepatic metabolism and inflammation may provide the basis for the development of sex-specific therapeutic strategies for the management of such an inflammatory-based metabolic disease and its cardio-metabolic consequences.
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Affiliation(s)
- Sara Della Torre
- Department of Pharmaceutical Sciences, University of Milan, Milan, Italy
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3
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Abstract
Growth hormone (GH) plays a pivotal role in many physiological processes in humans, and in other mammalian and non-mammalian vertebrate species, through actions on somatic growth, tissue development and repair, and intermediary metabolism. This review will focus on mechanisms of GH actions on gene expression, primarily from the perspective of the genes that encode proteins stimulated by GH to regulate somatic growth, especially insulin-like growth factor 1 (IGF-I), but also others that are induced or repressed by GH. Topics to be discussed will include a brief overview of GH-mediated signal transduction pathways and how these cascades alter the functions of responsive transcription factors, with a specific focus on STAT5B, a key member of the signal transducers and activators of transcription family, characterization of essential GH-regulated genes, and elucidation of mechanisms of their regulation from biochemical, genetic, and genomic perspectives.
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Affiliation(s)
- Peter Rotwein
- Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech Health University Health Sciences Center, El Paso, TX, 79905, USA.
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4
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Rotwein P. Diversification of the insulin-like growth factor 1 gene in mammals. PLoS One 2017; 12:e0189642. [PMID: 29240807 PMCID: PMC5730178 DOI: 10.1371/journal.pone.0189642] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 11/29/2017] [Indexed: 12/12/2022] Open
Abstract
Insulin-like growth factor 1 (IGF1), a small, secreted peptide growth factor, is involved in a variety of physiological and patho-physiological processes, including somatic growth, tissue repair, and metabolism of carbohydrates, proteins, and lipids. IGF1 gene expression appears to be controlled by several different signaling cascades in the few species in which it has been evaluated, with growth hormone playing a major role by activating a pathway involving the Stat5b transcription factor. Here, genes encoding IGF1 have been evaluated in 25 different mammalian species representing 15 different orders and ranging over ~180 million years of evolutionary diversification. Parts of the IGF1 gene have been fairly well conserved. Like rat Igf1 and human IGF1, 21 of 23 other genes are composed of 6 exons and 5 introns, and all 23 also contain recognizable tandem promoters, each with a unique leader exon. Exon and intron lengths are similar in most species, and DNA sequence conservation is moderately high in orthologous exons and proximal promoter regions. In contrast, putative growth hormone-activated Stat5b-binding enhancers found in analogous locations in rodent Igf1 and in human IGF1 loci, have undergone substantial variation in other mammals, and a processed retro-transposed IGF1 pseudogene is found in the sloth locus, but not in other mammalian genomes. Taken together, the fairly high level of organizational and nucleotide sequence similarity in the IGF1 gene among these 25 species supports the contention that some common regulatory pathways had existed prior to the beginning of mammalian speciation.
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Affiliation(s)
- Peter Rotwein
- Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America
- * E-mail:
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Xiong S, Mei J, Huang P, Jing J, Li Z, Kang J, Gui JF. Essential roles of stat5.1/stat5b in controlling fish somatic growth. J Genet Genomics 2017; 44:577-585. [PMID: 29246863 DOI: 10.1016/j.jgg.2017.07.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/21/2017] [Accepted: 07/19/2017] [Indexed: 01/09/2023]
Abstract
Signal transducer and activator of transcription 5b (STAT5b) has been identified as a key downstream mediator of growth hormone (GH) signaling in somatic growth of mammalian. However, the corresponding homologue gene of Stat5b is unknown in fish species. In this study, we generated loss-of-function mutants in stat5.1 and stat5.2, two stat5 homologues existing in zebrafish. In stat5.1-deficient zebrafish, a significant reduction of body length and body weight was detected in the embryos/larvae and adults compared with the wild-type control fish, and sexual size dimorphism in adult zebrafish was also eliminated. However, the stat5.2-deficient zebrafish displayed a normal developmental phenotype during all lifespan. Chromatin immunoprecipitation combined with deep sequencing (ChIP-seq) method was adopted to further investigate the potential transcriptional targets of Stat5 protein and cast much light upon the biological function of Stat5. We identified more than 800 genes as transcriptional targets of Stat5 during zebrafish embryogenesis. KEGG analysis indicated that the Stat5 target gene network is predominantly linked to the metabolic pathways, neuroactive ligand-receptor interaction and JAK-STAT signaling pathways. Further validation studies suggested that Stat5.1 protein could directly regulate the expression of gh1, and stat5.1-mutated zebrafish showed a reduction of gh1 mRNA level. In the present study, stat5.1 was revealed as the corresponding homologue gene of Stat5b in fish species. Additionally, we found a novel molecular interaction between Stat5.1/Stat5b and GH, and unraveled a positive feedback loop Stat5.1-GH-Stat5.1 which is necessary for somatic growth and body development in zebrafish.
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Affiliation(s)
- Shuting Xiong
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China
| | - Jie Mei
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China.
| | - Peipei Huang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Wuhan 430072, China
| | - Jing Jing
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China; Medical Research Institute, Wuhan University, Wuhan 430071, China
| | - Zhi Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Wuhan 430072, China
| | - Jingliang Kang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Wuhan 430072, China
| | - Jian-Fang Gui
- College of Fisheries, Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Wuhan 430072, China.
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Connerney J, Lau-Corona D, Rampersaud A, Waxman DJ. Activation of Male Liver Chromatin Accessibility and STAT5-Dependent Gene Transcription by Plasma Growth Hormone Pulses. Endocrinology 2017; 158:1386-1405. [PMID: 28323953 PMCID: PMC6283433 DOI: 10.1210/en.2017-00060] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 02/10/2017] [Indexed: 02/07/2023]
Abstract
Sex differences in pituitary growth hormone (GH) secretion (pulsatile in males vs near continuous/persistent in females) impart sex-dependent expression to hundreds of genes in adult mouse liver. Signal transducer and activator of transcription (STAT) 5, a GH-activated transcription factor that is essential for liver sexual dimorphism, is dynamically activated in direct response to each male plasma GH pulse. However, the impact of GH-induced STAT5 pulses on liver chromatin accessibility and downstream transcriptional events is unknown. In this study, we investigated the impact of a single pulse of GH given to hypophysectomized mice on local liver chromatin accessibility (DNase hypersensitive site analysis), transcription rates (heterogeneous nuclear RNA analysis), and gene expression (quantitative polymerase chain reaction and RNA sequencing) determined 30, 90, or 240 minutes later. The STAT5-dependent but sex-independent early GH response genes Igf1 and Cish showed rapid, GH pulse-induced increases in chromatin accessibility and gene transcription, reversing the effects of hypophysectomy. Rapid increases in liver chromatin accessibility and transcriptional activity were also induced in hypophysectomized male mice for some (Ces2b, Ugt2b38) but not for other liver STAT5-dependent male-biased genes (Cyp7b1). Moreover, in pituitary-intact male mice, Igf1, Cish, Ces2b, and Ugt2b38 all showed remarkable cycles of chromatin opening and closing, as well as associated cycles of induced gene transcription, which closely followed each endogenous pulse of liver STAT5 activity. Thus, the endogenous rhythms of male plasma GH pulsation dynamically open and then close liver chromatin at discrete, localized regulatory sites in temporal association with transcriptional activation of Igf1, Cish, and a subset of STAT5-dependent male-biased genes.
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Affiliation(s)
- Jeannette Connerney
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts 02215
| | - Dana Lau-Corona
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts 02215
| | - Andy Rampersaud
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts 02215
| | - David J Waxman
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts 02215
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7
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Mukherjee A, Alzhanov D, Rotwein P. Defining human insulin-like growth factor I gene regulation. Am J Physiol Endocrinol Metab 2016; 311:E519-29. [PMID: 27406741 PMCID: PMC5005972 DOI: 10.1152/ajpendo.00212.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/08/2016] [Indexed: 11/22/2022]
Abstract
Growth hormone (GH) plays an essential role in controlling somatic growth and in regulating multiple physiological processes in humans and other species. Insulin-like growth factor I (IGF-I), a conserved, secreted 70-amino acid peptide, is a critical mediator of many of the biological effects of GH. Previous studies have demonstrated that GH rapidly and potently promotes IGF-I gene expression in rodents and in some other mammals through the transcription factor STAT5b, leading to accumulation of IGF-I mRNAs and production of IGF-I. Despite this progress, very little is known about how GH or other trophic factors control human IGF1 gene expression, in large part because of the absence of any cellular model systems that robustly express IGF-I. Here, we have addressed mechanisms of regulation of human IGF-I by GH after generating cells in which the IGF1 chromosomal locus has been incorporated into a mouse cell line. Using this model, we found that physiological levels of GH rapidly stimulate human IGF1 gene transcription and identify several potential transcriptional enhancers in chromatin that bind STAT5b in a GH-regulated way. Each of the putative enhancers also activates a human IGF1 gene promoter in reconstitution experiments in the presence of the GH receptor, STAT5b, and GH. Thus we have developed a novel experimental platform that now may be used to determine how human IGF1 gene expression is controlled under different physiological and pathological conditions.
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Affiliation(s)
- Aditi Mukherjee
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon; and
| | - Damir Alzhanov
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon; and
| | - Peter Rotwein
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon; and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech Health University Health Sciences Center, El Paso, Texas
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8
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Alzhanov D, Mukherjee A, Rotwein P. Identifying growth hormone-regulated enhancers in the Igf1 locus. Physiol Genomics 2015; 47:559-68. [PMID: 26330488 DOI: 10.1152/physiolgenomics.00062.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/27/2015] [Indexed: 11/22/2022] Open
Abstract
Growth hormone (GH) plays a central role in regulating somatic growth and in controlling multiple physiological processes in humans and other vertebrates. A key agent in many GH actions is the secreted peptide, IGF-I. As established previously, GH stimulates IGF-I gene expression via the Stat5b transcription factor, leading to production of IGF-I mRNAs and proteins. However, the precise mechanisms by which GH-activated Stat5b promotes IGF-I gene transcription have not been defined. Unlike other GH-regulated genes, there are no Stat5b sites near either of the two IGF-I gene promoters. Although dispersed GH-activated Stat5b binding elements have been mapped in rodent Igf1 gene chromatin, it is unknown how these distal sites might function as potential transcriptional enhancers. Here we have addressed mechanisms of regulation of IGF-I gene transcription by GH by generating cell lines in which the rat Igf1 chromosomal locus has been incorporated into the mouse genome. Using these cells we find that physiological levels of GH rapidly and potently activate Igf1 gene transcription while stimulating physical interactions in chromatin between inducible Stat5b-binding elements and the Igf1 promoters. We have thus developed a robust experimental platform for elucidating how dispersed transcriptional enhancers control Igf1 gene expression under different biological conditions.
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Affiliation(s)
- Damir Alzhanov
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon; and
| | - Aditi Mukherjee
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon; and
| | - Peter Rotwein
- Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas
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9
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Reizel Y, Spiro A, Sabag O, Skversky Y, Hecht M, Keshet I, Berman BP, Cedar H. Gender-specific postnatal demethylation and establishment of epigenetic memory. Genes Dev 2015; 29:923-33. [PMID: 25934504 PMCID: PMC4421981 DOI: 10.1101/gad.259309.115] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
DNA methylation patterns are set up in a relatively fixed programmed manner during normal embryonic development and are then stably maintained. Using genome-wide analysis, we discovered a postnatal pathway involving gender-specific demethylation that occurs exclusively in the male liver. This demodification is programmed to take place at tissue-specific enhancer sequences, and our data show that the methylation state at these loci is associated with and appears to play a role in the transcriptional regulation of nearby genes. This process is mediated by the secretion of testosterone at the time of sexual maturity, but the resulting methylation profile is stable and therefore can serve as an epigenetic memory even in the absence of this inducer. These findings add a new dimension to our understanding of the role of DNA methylation in vivo and provide the foundations for deciphering how environment can impact on the epigenetic regulation of genes in general.
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Affiliation(s)
- Yitzhak Reizel
- Department of Developmental Biology and Cancer Research, Hebrew University Medical School, Jerusalem 91120, Israel
| | - Adam Spiro
- Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ofra Sabag
- Department of Developmental Biology and Cancer Research, Hebrew University Medical School, Jerusalem 91120, Israel
| | - Yael Skversky
- Department of Developmental Biology and Cancer Research, Hebrew University Medical School, Jerusalem 91120, Israel
| | - Merav Hecht
- Department of Developmental Biology and Cancer Research, Hebrew University Medical School, Jerusalem 91120, Israel
| | - Ilana Keshet
- Department of Developmental Biology and Cancer Research, Hebrew University Medical School, Jerusalem 91120, Israel
| | - Benjamin P Berman
- Bioinformatics and Computational Biology Research Center, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA
| | - Howard Cedar
- Department of Developmental Biology and Cancer Research, Hebrew University Medical School, Jerusalem 91120, Israel;
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10
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Nguyen M, Boutinaud M, Pétridou B, Gabory A, Pannetier M, Chat S, Bouet S, Jouneau L, Jaffrezic F, Laloë D, Klopp C, Brun N, Kress C, Jammes H, Charlier M, Devinoy E. DNA methylation and transcription in a distal region upstream from the bovine AlphaS1 casein gene after once or twice daily milking. PLoS One 2014; 9:e111556. [PMID: 25369064 PMCID: PMC4219721 DOI: 10.1371/journal.pone.0111556] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 10/02/2014] [Indexed: 12/31/2022] Open
Abstract
Once daily milking (ODM) induces a reduction in milk production when compared to twice daily milking (TDM). Unilateral ODM of one udder half and TDM of the other half, enables the study of underlying mechanisms independently of inter-individual variability (same genetic background) and of environmental factors. Our results show that in first-calf heifers three CpG, located 10 kb upstream from the CSN1S1 gene were methylated to 33, 34 and 28%, respectively, after TDM but these levels were higher after ODM, 38, 38 and 33%, respectively. These methylation levels were much lower than those observed in the mammary gland during pregnancy (57, 59 and 50%, respectively) or in the liver (74, 78 and 61%, respectively). The methylation level of a fourth CpG (CpG4), located close by (29% during TDM) was not altered after ODM. CpG4 methylation reached 39.7% and 59.5%, during pregnancy or in the liver, respectively. CpG4 is located within a weak STAT5 binding element, arranged in tandem with a second high affinity STAT5 element. STAT5 binding is only marginally modulated by CpG4 methylation, but it may be altered by the methylation levels of the three other CpG nearby. Our results therefore shed light on mechanisms that help to explain how milk production is almost, but not fully, restored when TDM is resumed (15.1±0.2 kg/day instead of 16.2±0.2 kg/day, p<0.01). The STAT5 elements are 100 bp away from a region transcribed in the antisense orientation, in the mammary gland during lactation, but not during pregnancy or in other reproductive organs (ovary or testes). We now need to clarify whether the transcription of this novel RNA is a consequence of STAT5 interacting with the CSN1S1 distal region, or whether it plays a role in the chromatin structure of this region.
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Affiliation(s)
- Minh Nguyen
- INRA, UMR1313 Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Marion Boutinaud
- INRA, UMR1348 Physiologie Environnement et Génétique pour l′Animal et les Systèmes d′Elevage, Saint-Gilles, France
| | - Barbara Pétridou
- INRA, UMR1313 Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Anne Gabory
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
| | - Maëlle Pannetier
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
| | - Sophie Chat
- INRA, UMR1313 Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Stephan Bouet
- INRA, UMR1313 Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Luc Jouneau
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
| | - Florence Jaffrezic
- INRA, UMR1313 Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Denis Laloë
- INRA, UMR1313 Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Christophe Klopp
- INRA, Sigenae, UR875 Biométrie et Intelligence Artificielle, Castanet-Tolosan, France
| | - Nicolas Brun
- INRA, UMR1313 Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Clémence Kress
- INSERM U846 Stem Cell and Brain Research Institute, INRA, USC1361 AGROBIOSYSTEM, Université de Lyon 1 UMR S 846, Bron, France
| | - Hélène Jammes
- INRA, UMR1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France
| | - Madia Charlier
- INRA, UMR1313 Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Eve Devinoy
- INRA, UMR1313 Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
- * E-mail:
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11
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Lin G, LaPensee CR, Qin ZS, Schwartz J. Reciprocal occupancy of BCL6 and STAT5 on Growth Hormone target genes: contrasting transcriptional outcomes and promoter-specific roles of p300 and HDAC3. Mol Cell Endocrinol 2014; 395:19-31. [PMID: 25088465 PMCID: PMC4176921 DOI: 10.1016/j.mce.2014.07.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 06/30/2014] [Accepted: 07/28/2014] [Indexed: 12/30/2022]
Abstract
Expression of the Growth Hormone (GH)-stimulated gene Socs2 (Suppressor of Cytokine Signaling 2) is mediated by the transcription activator STAT5 (Signal Transducer and Activator of Transcription 5) and the transcription repressor BCL6 (B-Cell Lymphoma 6). ChIP-Sequencing identified Cish (Cytokine-Inducible SH2-containing protein) and Bcl6 as having similar patterns of reciprocal occupancy by BCL6 and STAT5 in response to GH, though GH stimulates Cish and inhibits Bcl6 expression. The co-activator p300 occupied Socs2, Cish and Bcl6 promoters, and enhanced STAT5-mediated activation of Socs2 and Cish. In contrast, on Bcl6, p300 functioned as a repressor and inhibited in conjunction with STAT5 or BCL6. The co-repressor HDAC3 (Histone deacetylase 3) inhibited the Socs2, Cish and Bcl6 promoters in the presence of STAT5. Thus transcriptional outcomes on GH-regulated genes occupied by BCL6 and STAT5 are determined in a promoter-specific fashion by co-regulatory proteins which mediate the distinction between activating and repressive transcription factors.
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Affiliation(s)
- Grace Lin
- Cellular & Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Christopher R LaPensee
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Zhaohui S Qin
- Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA, USA
| | - Jessica Schwartz
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
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12
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Steegenga WT, Mischke M, Lute C, Boekschoten MV, Pruis MG, Lendvai A, Verkade HJ, Boekhorst J, Timmerman HM, Plösch T, Müller M. Sexually dimorphic characteristics of the small intestine and colon of prepubescent C57BL/6 mice. Biol Sex Differ 2014; 5:11. [PMID: 25243059 PMCID: PMC4169057 DOI: 10.1186/s13293-014-0011-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 08/20/2014] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND There is increasing appreciation for sexually dimorphic effects, but the molecular mechanisms underlying these effects are only partially understood. In the present study, we explored transcriptomics and epigenetic differences in the small intestine and colon of prepubescent male and female mice. In addition, the microbiota composition of the colonic luminal content has been examined. METHODS At postnatal day 14, male and female C57BL/6 mice were sacrificed and the small intestine, colon and content of luminal colon were isolated. Gene expression of both segments of the intestine was analysed by microarray analysis. DNA methylation of the promoter regions of selected sexually dimorphic genes was examined by pyrosequencing. Composition of the microbiota was explored by deep sequencing. RESULTS Sexually dimorphic genes were observed in both segments of the intestine of 2-week-old mouse pups, with a stronger effect in the small intestine. Amongst the total of 349 genes displaying a sexually dimorphic effect in the small intestine and/or colon, several candidates exhibited a previously established function in the intestine (i.e. Nts, Nucb2, Alox5ap and Retnlγ). In addition, differential expression of genes linked to intestinal bowel disease (i.e. Ccr3, Ccl11 and Tnfr) and colorectal cancer development (i.e. Wt1 and Mmp25) was observed between males and females. Amongst the genes displaying significant sexually dimorphic expression, nine genes were histone-modifying enzymes, suggesting that epigenetic mechanisms might be a potential underlying regulatory mechanism. However, our results reveal no significant changes in DNA methylation of analysed CpGs within the selected differentially expressed genes. With respect to the bacterial community composition in the colon, a dominant effect of litter origin was found but no significant sex effect was detected. However, a sex effect on the dominance of specific taxa was observed. CONCLUSIONS This study reveals molecular dissimilarities between males and females in the small intestine and colon of prepubescent mice, which might underlie differences in physiological functioning and in disease predisposition in the two sexes.
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Affiliation(s)
- Wilma T Steegenga
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - Mona Mischke
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - Carolien Lute
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - Mark V Boekschoten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands
| | - Maurien Gm Pruis
- Center for Liver, Digestive and Metabolic Diseases, Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Agnes Lendvai
- Center for Liver, Digestive and Metabolic Diseases, Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Henkjan J Verkade
- Center for Liver, Digestive and Metabolic Diseases, Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | | | - Torsten Plösch
- Department of Obstetrics and Gynaecology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Michael Müller
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands ; Norwich Medical School, University of East Anglia, Norwich, UK
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Uren RT, Turnley AM. Regulation of neurotrophin receptor (Trk) signaling: suppressor of cytokine signaling 2 (SOCS2) is a new player. Front Mol Neurosci 2014; 7:39. [PMID: 24860421 PMCID: PMC4030161 DOI: 10.3389/fnmol.2014.00039] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 04/21/2014] [Indexed: 12/17/2022] Open
Abstract
The classic neurotrophins Nerve Growth Factor (NGF), Brain Derived Neurotrophic Factor (BDNF) and Neurotrophins NT-3 and NT-4 are well known to regulate various aspects of neuronal differentiation, survival and growth. They do this by binding to their cognate receptors, members of the Tropomyosin-related kinase (Trk) receptor tyrosine kinase family, namely TrkA, TrkB, and TrkC. These receptors are then internalized and localized to different cellular compartments, where signal transduction occurs. Conversely, members of the suppressor of cytokine signaling (SOCS) family are best known as negative regulators of signaling via the JAK/STAT pathway. Some members of the family, and in particular SOCS2, have roles in the nervous system that at least partially overlap with that of neurotrophins, namely neuronal differentiation and neurite outgrowth. Recent evidence suggests that SOCS2 is a novel regulator of NGF signaling, altering TrkA cellular localization and downstream signaling to affect neurite growth but not neuronal survival. This review first discusses regulation of Trk receptor signaling, followed by the role of SOCS2 in the nervous system and finishes with a discussion of possible mechanisms by which SOCS2 may regulate TrkA function.
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Affiliation(s)
- Rachel T Uren
- Neural Regeneration Laboratory, Centre for Neuroscience Research and Department of Anatomy and Neuroscience, The University of Melbourne Melbourne, VIC, Australia
| | - Ann M Turnley
- Neural Regeneration Laboratory, Centre for Neuroscience Research and Department of Anatomy and Neuroscience, The University of Melbourne Melbourne, VIC, Australia
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Chia DJ. Minireview: mechanisms of growth hormone-mediated gene regulation. Mol Endocrinol 2014; 28:1012-25. [PMID: 24825400 DOI: 10.1210/me.2014-1099] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
GH exerts a diverse array of physiological actions that include prominent roles in growth and metabolism, with a major contribution via stimulating IGF-1 synthesis. GH achieves its effects by influencing gene expression profiles, and Igf1 is a key transcriptional target of GH signaling in liver and other tissues. This review examines the mechanisms of GH-mediated gene regulation that begin with signal transduction pathways activated downstream of the GH receptor and continue with chromatin events at target genes and additionally encompasses the topics of negative regulation and cross talk with other cellular inputs. The transcription factor, signal transducer and activator of transcription 5b, is regarded as the major signaling pathway by which GH achieves its physiological effects, including in stimulating Igf1 gene transcription in liver. Recent studies exploring the mechanisms of how activated signal transducer and activator of transcription 5b accomplishes this are highlighted, which begin to characterize epigenetic features at regulatory domains of the Igf1 locus. Further research in this field offers promise to better understand the GH-IGF-1 axis in normal physiology and disease and to identify strategies to manipulate the axis to improve human health.
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Affiliation(s)
- Dennis J Chia
- Department of Pediatrics, Icahn School of Medicine at Mt Sinai, New York, New York 10029
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15
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Jiao Y, Rieck S, Le Lay J, Kaestner KH. CISH has no non-redundant functions in glucose homeostasis or beta cell proliferation during pregnancy in mice. Diabetologia 2013; 56:2435-45. [PMID: 23949579 PMCID: PMC3816496 DOI: 10.1007/s00125-013-3014-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 07/16/2013] [Indexed: 10/26/2022]
Abstract
AIMS/HYPOTHESIS Increased beta cell proliferation during pregnancy is mediated by the Janus kinase 2/signal transducer and activator of transcription 5 (JAK2/STAT5) signalling pathway in response to increased lactogen levels. Activation of the pathway leads to transcriptional upregulation of Cish (encoding cytokine-inducible SH2 domain-containing protein), a member of the suppressor of cytokine signalling (SOCS) family of genes, forming a negative-feedback loop. Here, we examined whether conditional gene ablation of Cish in the pancreas improves beta cell proliferation and beta cell function during pregnancy in mice. METHODS We derived mice with a novel, conditional loxP allele for Cish. Pancreas-specific ablation of Cish was achieved by crossing Cish (loxP/loxP) mice with Pdx1-Cre (Early) mice. Beta cell proliferation was quantified by BrdU labelling. Glucose homeostasis was examined with glucose tolerance tests and determination of plasma insulin levels. The expression of other Socs genes and target genes of p-STAT5 related to beta cell function and beta cell proliferation was determined by quantitative PCR. RESULTS There was no difference in beta cell proliferation or glucose homeostasis between the Cish mutant group and the control group. The p-STAT5 protein level was the same in Cish mutant and control mice. Socs2 gene expression was higher in Cish mutant than control mice at pregnancy day 9.5. The expression of other Socs genes was the same between control and mutant mice. CONCLUSIONS/INTERPRETATION Our results show that CISH has no non-redundant functions in beta cell proliferation or glucose homeostasis during pregnancy in mice. Socs2 might compensate for the loss of Cish during pregnancy.
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Affiliation(s)
- Yang Jiao
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Sebastian Rieck
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - John Le Lay
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Klaus H. Kaestner
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- 12-126 Smilow Center for Translational Research, 3400 Civic Center Blvd Bldg 421, Philadelphia, PA 19104-5156
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Jiang H, Ge X. MEAT SCIENCE AND MUSCLE BIOLOGY SYMPOSIUM--mechanism of growth hormone stimulation of skeletal muscle growth in cattle. J Anim Sci 2013; 92:21-9. [PMID: 24166991 DOI: 10.2527/jas.2013-7095] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Growth hormone, also called somatotropin (ST), is a polypeptide hormone produced by the anterior pituitary. The major functions of GH include stimulating bone and skeletal muscle growth, lipolysis, milk production, and expression of the IGF-I gene in the liver. Based on these functions, recombinant bovine ST (bST) and recombinant porcine ST (pST) have been used to improve milk production in dairy cows and lean tissue growth in pigs, respectively. However, despite these applications, the mechanisms of action of GH are not fully understood. Indeed, there has been a lot of controversy over the role of liver-derived circulating IGF-I and locally produced IGF-I in mediating the growth-stimulatory effect of GH during the last 15 yr. It is in this context that we have conducted studies to further understand how GH stimulates skeletal muscle growth in cattle. Our results do not support a role of skeletal muscle-derived IGF-I in GH-stimulated skeletal muscle growth in cattle. Our results indicate that GH stimulates skeletal muscle growth in cattle, in part, by stimulating protein synthesis in muscle through a GH receptor-mediated, IGF-I-independent mechanism. In this review, besides discussing these results, we also argue that liver-derived circulating IGF-I should be still considered as the major mechanism that mediates the growth-stimulatory effect of GH on skeletal muscle in cattle and other domestic animals.
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Affiliation(s)
- H Jiang
- Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg 24060
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Santhanam M, Chia DJ. Hepatic-specific accessibility of Igf1 gene enhancers is independent of growth hormone signaling. Mol Endocrinol 2013; 27:2080-92. [PMID: 24109593 DOI: 10.1210/me.2013-1181] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The diverse roles of IGF-1 in physiology include acting as the endocrine intermediate to elicit the anabolic actions of GH. The majority of serum IGF-1 is synthesized in liver, where GH stimulates Igf1 gene transcription via the transcription factor, signal transducer and activator of transcription (Stat)5b. We and others have identified multiple Stat5-binding domains at the Igf1 locus that function in gene regulation, but it remains unclear whether the roles of these domains are tissue specific. Survey of the chromatin landscape of regulatory domains can provide insight about mechanisms of gene regulation, with chromatin accessibility regarded as a hallmark feature of regulatory domains. We prepared chromatin from liver, kidney, and spleen of C57BL/6 mice, and used formaldehyde-associated isolation of regulatory elements to assess chromatin accessibility at the major Igf1 promoter and 7 -binding enhancers. Whereas the promoters of other prototypical tissue-specific genes are open in a tissue-specific way, the major Igf1 promoter is open in all 3 tissues, albeit moderately more so in liver. In contrast, chromatin accessibility at Igf1 Stat5-binding domains is essentially restricted to liver, indicating that the enhancers are driving extensive differences in tissue expression. Furthermore, studies with Ghrhr(lit/lit) mice reveal that prior GH exposure is not necessary to establish open chromatin at these domains. Lastly, formaldehyde-associated isolation of regulatory elements of human liver samples confirms open chromatin at IGF1 Promoter 1, but unexpectedly, homologous Stat5-binding motifs are not accessible. We conclude that robust GH-stimulated hepatic Igf1 gene transcription utilizes tissue-specific mechanisms of epigenetic regulation that are established independent of GH signaling.
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Affiliation(s)
- Mahalakshmi Santhanam
- Division of Pediatric Endocrinology & Diabetes, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1616, New York, NY 10029.
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Grange M, Verdeil G, Arnoux F, Griffon A, Spicuglia S, Maurizio J, Buferne M, Schmitt-Verhulst AM, Auphan-Anezin N. Active STAT5 regulates T-bet and eomesodermin expression in CD8 T cells and imprints a T-bet-dependent Tc1 program with repressed IL-6/TGF-β1 signaling. THE JOURNAL OF IMMUNOLOGY 2013; 191:3712-24. [PMID: 24006458 DOI: 10.4049/jimmunol.1300319] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In adoptive therapy, CD8 T cells expressing active STAT5 (STAT5CA) transcription factors were found to be superior to unmanipulated counterparts in long-term persistence, capacity to infiltrate autochthonous mouse melanomas, thrive in their microenvironment, and induce their regression. However, the molecular mechanisms sustaining these properties were undefined. In this study, we report that STAT5CA induced sustained expression of genes controlling tissue homing, cytolytic granule composition, type 1 CD8 cytotoxic T cell-associated effector molecules granzyme B(+), IFN-γ(+), TNF-α(+), and CCL3(+), but not IL-2, and transcription factors T-bet and eomesodermin (Eomes). Chromatin immunoprecipitation sequencing analyses identified the genes possessing regulatory regions to which STAT5 bound in long-term in vivo maintained STAT5CA-expressing CD8 T cells. This analysis identified 34% of the genes differentially expressed between STAT5CA-expressing and nonexpressing effector T cells as direct STAT5CA target genes, including those encoding T-bet, Eomes, and granzyme B. Additionally, genes encoding the IL-6R and TGFbRII subunits were stably repressed, resulting in dampened IL-17-producing CD8 T cell polarization in response to IL-6 and TGF-β1. The absence of T-bet did not affect STAT5CA-driven accumulation of the T cells in tissue or their granzyme B expression but restored IL-2 secretion and IL-6R and TGFbRII expression and signaling, as illustrated by IL-17 induction. Therefore, concerted STAT5/T-bet/Eomes regulation controls homing, long-term maintenance, recall responses, and resistance to polarization towards IL-17-producing CD8 T cells while maintaining expression of an efficient type 1 CD8 cytotoxic T cell program (granzyme B(+), IFN-γ(+)).
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Affiliation(s)
- Magali Grange
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université, Marseille 13288, France
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Varco-Merth B, Mirza K, Alzhanov DT, Chia DJ, Rotwein P. Biochemical characterization of diverse Stat5b-binding enhancers that mediate growth hormone-activated insulin-like growth factor-I gene transcription. PLoS One 2012. [PMID: 23185594 PMCID: PMC3502335 DOI: 10.1371/journal.pone.0050278] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Many of the biological effects of growth hormone (GH) are mediated by insulin-like growth factor I (IGF-I), a 70-amino acid secreted peptide whose gene expression is rapidly induced by GH via the Stat5b transcription factor. We previously identified multiple evolutionarily conserved GH-activated chromosomal binding domains for Stat5b within the rat Igf1 locus, and proposed that they could regulate IGF-I gene activity. Here we investigate the biochemical and functional characteristics of these putative long-range transcriptional enhancers. Each element contained 2 or 3 individual Stat5b recognition sequences that could bind Stat5b in vitro, but with affinities that varied over a >100-fold range. Full transcriptional responsiveness to GH required that all Stat5b sites be intact within an individual enhancer. Replacement of a single lower-affinity Stat5b sequence with a higher-affinity one increased in vitro binding of Stat5b, and boosted transcriptional potency of the entire element to GH. As enhanced transcriptional activity involved changes in only one or two nucleotides within an enhancer DNA segment, there appears to be remarkable specificity and sensitivity in the ability of Stat5b to transform DNA binding activity into transcriptional function. Stat5b was able to stimulate the transcriptional activity of two enhancers in the absence of GH, indicating that individual Stat5b-regulated elements possess distinct functional features. We conclude that combinatorial interplay among multiple Stat5b-binding response elements with distinguishable biochemical properties is responsible for highly regulated control of IGF-I gene activity by GH.
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Affiliation(s)
- Ben Varco-Merth
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Kasim Mirza
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Damir T. Alzhanov
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Dennis J. Chia
- Department of Pediatrics, Mt. Sinai School of Medicine, New York, New York, United States of America
| | - Peter Rotwein
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon, United States of America
- * E-mail:
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20
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Mueller KM, Themanns M, Friedbichler K, Kornfeld JW, Esterbauer H, Tuckermann JP, Moriggl R. Hepatic growth hormone and glucocorticoid receptor signaling in body growth, steatosis and metabolic liver cancer development. Mol Cell Endocrinol 2012; 361:1-11. [PMID: 22564914 PMCID: PMC3419266 DOI: 10.1016/j.mce.2012.03.026] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 03/30/2012] [Indexed: 01/07/2023]
Abstract
Growth hormone (GH) and glucocorticoids (GCs) are involved in the control of processes that are essential for the maintenance of vital body functions including energy supply and growth control. GH and GCs have been well characterized to regulate systemic energy homeostasis, particular during certain conditions of physical stress. However, dysfunctional signaling in both pathways is linked to various metabolic disorders associated with aberrant carbohydrate and lipid metabolism. In liver, GH-dependent activation of the transcription factor signal transducer and activator of transcription (STAT) 5 controls a variety of physiologic functions within hepatocytes. Similarly, GCs, through activation of the glucocorticoid receptor (GR), influence many important liver functions such as gluconeogenesis. Studies in hepatic Stat5 or GR knockout mice have revealed that they similarly control liver function on their target gene level and indeed, the GR functions often as a cofactor of STAT5 for GH-induced genes. Gene sets, which require physical STAT5-GR interaction, include those controlling body growth and maturation. More recently, it has become evident that impairment of GH-STAT5 signaling in different experimental models correlates with metabolic liver disease, ranging from hepatic steatosis to hepatocellular carcinoma (HCC). While GH-activated STAT5 has a protective role in chronic liver disease, experimental disruption of GC-GR signaling rather seems to ameliorate metabolic disorders under metabolic challenge. In this review, we focus on the current knowledge about hepatic GH-STAT5 and GC-GR signaling in body growth, metabolism, and protection from fatty liver disease and HCC development.
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Affiliation(s)
| | | | | | - Jan-Wilhelm Kornfeld
- Institute for Genetics, Department of Mouse Genetics and Metabolism, University of Cologne, Cologne, Germany
| | - Harald Esterbauer
- Department of Laboratory Medicine, Medical University Vienna, Vienna, Austria
| | - Jan P. Tuckermann
- Tissue-Specific Hormone Action, Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany
- Institute for General Zoology and Endocrinology, University of Ulm, Ulm, Germany
| | - Richard Moriggl
- Ludwig Boltzmann Institute for Cancer Research, Vienna, Austria
- Corresponding author. Address: Ludwig Boltzmann Institute for Cancer Research, Waehringerstrasse 13a, 1090 Vienna, Austria. Tel.: +43 14277 64111; fax: +43 14277 9641.
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The KRAB zinc finger protein RSL1 regulates sex- and tissue-specific promoter methylation and dynamic hormone-responsive chromatin configuration. Mol Cell Biol 2012; 32:3732-42. [PMID: 22801370 DOI: 10.1128/mcb.00615-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Over 400 Krüppel-associated box zinc finger proteins (KRAB-ZFPs) are encoded in mammalian genomes. While KRAB-ZFPs strongly repress transcription in vitro, little is known about their biological function or gene targets in vivo. Regulator of sex limitation 1 (Rsl1), one of the first KRAB-Zfp genes assigned a physiological role, accentuates sex-biased liver gene expression, most dramatically for mouse sex-limited protein (Slp), which provides an in vivo reporter of KRAB-ZFP function. Slp is induced in males in the liver and kidney by growth hormone (GH) and androgen, respectively. In the liver but not kidney, the Rsl1 genotype correlates with methylation of a CpG dinucleotide in the Slp promoter that is demethylated at puberty. RSL1 binds 2 kb upstream of the Slp promoter, both in vitro and in vivo, within an enhancer containing response elements for STAT5b. Chromatin immunoprecipitation (ChIP) assays demonstrate that RSL1 recruits KAP1/TRIM28, the corepressor for KRAB action in vitro, to this enhancer. Slp induction requires rapid cycling of STAT5b in chromatin. Remarkably, RSL1 simultaneously binds adjacent to STAT5b with a reciprocal binding pattern that limits hormonal response. These experiments demonstrate a surprisingly dynamic interplay between a hormonal activator, STAT5b, and a KRAB-ZFP repressor and provide unique insights into KRAB-ZFP epigenetic mechanisms.
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Stavreva DA, Varticovski L, Hager GL. Complex dynamics of transcription regulation. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1819:657-66. [PMID: 22484099 PMCID: PMC3371156 DOI: 10.1016/j.bbagrm.2012.03.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 03/10/2012] [Accepted: 03/15/2012] [Indexed: 01/10/2023]
Abstract
Transcription is a tightly regulated cellular function which can be triggered by endogenous (intrinsic) or exogenous (extrinsic) signals. The development of novel techniques to examine the dynamic behavior of transcription factors and the analysis of transcriptional activity at the single cell level with increased temporal resolution has revealed unexpected elements of stochasticity and dynamics of this process. Emerging research reveals a complex picture, wherein a wide range of time scales and temporal transcription patterns overlap to generate transcriptional programs. The challenge now is to develop a perspective that can guide us to common underlying mechanisms, and consolidate these findings. Here we review the recent literature on temporal dynamics and stochastic gene regulation patterns governed by intrinsic or extrinsic signals, utilizing the glucocorticoid receptor (GR)-mediated transcriptional model to illustrate commonality of these emerging concepts. This article is part of a Special Issue entitled: Chromatin in time and space.
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Affiliation(s)
- Diana A Stavreva
- Laboratory of Receptor Biology and Gene Expression, Building 41, B507, 41 Library Dr., National Cancer Institute, NIH, Bethesda, MD 20892, USA.
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Rotwein P. Mapping the growth hormone--Stat5b--IGF-I transcriptional circuit. Trends Endocrinol Metab 2012; 23:186-93. [PMID: 22361342 PMCID: PMC3313013 DOI: 10.1016/j.tem.2012.01.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 01/10/2012] [Accepted: 01/20/2012] [Indexed: 12/13/2022]
Abstract
Growth hormone (GH) and insulin-like growth factor-I (IGF-I) exert powerful influences on somatic growth, metabolism, and tissue repair, and have been implicated in aging and carcinogenesis. Since the formulation of the somatomedin hypothesis over 50 years ago, GH and IGF-I have been linked intimately to one another. Recent studies have established that GH potently stimulates IGF-I gene transcription, and through this mechanism controls production of IGF-I. A key mediator of the GH-IGF-I biosynthetic pathway is the latent transcription factor Stat5b. This review summarizes the potentially complex mechanistic relationship between GH action, Stat5b, and IGF-I gene activation, and suggests that Stat5b may have a broad role in mediating IGF-I gene regulation in response to diverse physiological inputs.
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Affiliation(s)
- Peter Rotwein
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, OR 97239-3098, USA.
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Dynamic, sex-differential STAT5 and BCL6 binding to sex-biased, growth hormone-regulated genes in adult mouse liver. Mol Cell Biol 2011; 32:880-96. [PMID: 22158971 DOI: 10.1128/mcb.06312-11] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Sex-dependent pituitary growth hormone (GH) secretory patterns determine the sex-biased expression of >1,000 genes in mouse and rat liver, affecting lipid and drug metabolism, inflammation, and disease. A fundamental biological question is how robust differential expression can be achieved for hundreds of sex-biased genes simply based on the GH input signal pattern: pulsatile GH stimulation in males versus near-continuous GH exposure in females. STAT5 is an essential transcriptional mediator of the sex-dependent effects of GH in the liver, but the mechanisms that underlie its sex-dependent actions are obscure. Here we elucidate the dynamic, sex-dependent binding of STAT5 and the GH/STAT5-regulated repressor BCL6 to mouse liver chromatin genome wide, revealing a counteractive interplay between these two regulators of sex differences in liver gene expression. Our findings establish a close correlation between sex-dependent STAT5 binding and sex-biased target gene expression. Moreover, sex-dependent STAT5 binding correlated positively with sex-biased DNase hypersensitivity and H3-K4me1 and H3-K4me3 (activating) marks, correlated negatively with sex-biased H3-K27me3 (repressive) marks, and was associated with sex-differentially enriched motifs for HNF6/CDP factors. Importantly, BCL6 binding was preferentially associated with repression of female-biased STAT5 targets in male liver. Furthermore, BCL6 and STAT5 common targets but not BCL6 unique targets showed strong enrichment for lipid and drug metabolism. These findings provide a comprehensive, genome-wide view of the mechanisms whereby these two GH-regulated transcription factors establish and maintain sex differences affecting liver physiology and disease. The approaches used here to characterize sex-dependent STAT5 and BCL6 binding can be applied to other condition-specific regulatory factors and binding sites and their interplay with cooperative chromatin binding factors.
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Baik M, Yu JH, Hennighausen L. Growth hormone-STAT5 regulation of growth, hepatocellular carcinoma, and liver metabolism. Ann N Y Acad Sci 2011; 1229:29-37. [PMID: 21793836 PMCID: PMC3427656 DOI: 10.1111/j.1749-6632.2011.06100.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The liver is a primary target of growth hormone (GH). GH signals are mediated by the transcription factor signal transducer and activator of transcription 5 (STAT5). Here, we focus on recent discoveries about the role of GH-STAT5 signaling in hepatic physiology and pathophysiology. We discuss roles of the GH-STAT5 axis in body growth, lipid metabolism, and the cell cycle pertaining to hepatosteatosis, fibrosis, and hepatocellular carcinoma. Finally, we discuss recent discoveries about the role of GH-STAT5 in sex-specific gene expression and bile acid, steroid, and drug metabolism.
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Affiliation(s)
- Myunggi Baik
- Deptartment of Molecular Biotechnology, WCU-RNNM, Chonnam National University, Gwangju, Republic of Korea
| | - Ji Hoon Yu
- Laboratory of Genetics and Physiology, National Institutes of Health, Bethesda, Maryland
| | - Lothar Hennighausen
- Laboratory of Genetics and Physiology, National Institutes of Health, Bethesda, Maryland
- Deptartment of Molecular Biotechnology, WCU-RNNM, Chonnam National University, Gwangju, Republic of Korea
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Hochberg Z, Feil R, Constancia M, Fraga M, Junien C, Carel JC, Boileau P, Le Bouc Y, Deal CL, Lillycrop K, Scharfmann R, Sheppard A, Skinner M, Szyf M, Waterland RA, Waxman DJ, Whitelaw E, Ong K, Albertsson-Wikland K. Child health, developmental plasticity, and epigenetic programming. Endocr Rev 2011; 32:159-224. [PMID: 20971919 PMCID: PMC3365792 DOI: 10.1210/er.2009-0039] [Citation(s) in RCA: 401] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 08/27/2010] [Indexed: 11/19/2022]
Abstract
Plasticity in developmental programming has evolved in order to provide the best chances of survival and reproductive success to the organism under changing environments. Environmental conditions that are experienced in early life can profoundly influence human biology and long-term health. Developmental origins of health and disease and life-history transitions are purported to use placental, nutritional, and endocrine cues for setting long-term biological, mental, and behavioral strategies in response to local ecological and/or social conditions. The window of developmental plasticity extends from preconception to early childhood and involves epigenetic responses to environmental changes, which exert their effects during life-history phase transitions. These epigenetic responses influence development, cell- and tissue-specific gene expression, and sexual dimorphism, and, in exceptional cases, could be transmitted transgenerationally. Translational epigenetic research in child health is a reiterative process that ranges from research in the basic sciences, preclinical research, and pediatric clinical research. Identifying the epigenetic consequences of fetal programming creates potential applications in clinical practice: the development of epigenetic biomarkers for early diagnosis of disease, the ability to identify susceptible individuals at risk for adult diseases, and the development of novel preventive and curative measures that are based on diet and/or novel epigenetic drugs.
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Affiliation(s)
- Z Hochberg
- Rambam Medical Center, Rappaport Faculty of Medicine and Research Institute, Technion–Israel Institute of Technology, Haifa, Israel.
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Rodenburg EM, Stricker BHC, Visser LE. Sex-related differences in hospital admissions attributed to adverse drug reactions in the Netherlands. Br J Clin Pharmacol 2011; 71:95-104. [PMID: 21143505 DOI: 10.1111/j.1365-2125.2010.03811.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Women are more at risk for developing adverse drug reactions (ADRs) due to differences in pharmacokinetics, pharmacodynamics and drug use. ADRs regularly lead to hospital admissions. WHAT THIS STUDY ADDS There are differences between the sexes in hospital admissions attributed to ADRs. The risk of being hospitalized with an ADR varies between the sexes in the type of reaction and the causative drug. AIM Adverse drug reactions (ADRs) are a major burden in health care, regularly leading to hospital admission, morbidity or death. Women tend to have a higher risk of adverse drug reactions with a 1.5 to 1.7-fold greater risk than men. Our primary aim was to study differences in ADR-related hospitalizations between the sexes. METHODS We conducted a nationwide study of all ADR-related hospitalizations in the period between 2000 and 2005 in the Netherlands, which were selected from all 9,287,162 hospital admissions in this period. ADR-drug group combinations with at least 50 admissions in one of the sexes were selected. Relative risks and confidence intervals were calculated with respect to total admissions and total prescriptions with men as reference. RESULTS In total, 0.41% of the 4,236,368 admissions in men (95% CI 0.40, 0.42%) and 0.47% of the 5,050,794 admissions in women (95% CI 0.46, 0.48%) were attributed to an ADR by medical specialists (57% of all ADR-related admissions were in women). Differences between the sexes in risk for ADR-related hospitalization were found for antineoplastic and immunosuppressive drugs, antirheumatics, anticoagulants and salicylates, cardiovascular and neurological drugs, steroids and antibiotics. In certain drug categories, risks for hospitalization changed after taking into account total drug prescriptions. CONCLUSION In all different drug classes, significant differences exist between the sexes in ADR-related hospital admissions. Cardiovascular drugs account for the most pronounced differences between men and women. More research is needed to explain the clear sex differences in ADR-related hospital admissions.
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Affiliation(s)
- Eline M Rodenburg
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands
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Unbiased, genome-wide in vivo mapping of transcriptional regulatory elements reveals sex differences in chromatin structure associated with sex-specific liver gene expression. Mol Cell Biol 2010; 30:5531-44. [PMID: 20876297 DOI: 10.1128/mcb.00601-10] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We have used a simple and efficient method to identify condition-specific transcriptional regulatory sites in vivo to help elucidate the molecular basis of sex-related differences in transcription, which are widespread in mammalian tissues and affect normal physiology, drug response, inflammation, and disease. To systematically uncover transcriptional regulators responsible for these differences, we used DNase hypersensitivity analysis coupled with high-throughput sequencing to produce condition-specific maps of regulatory sites in male and female mouse livers and in livers of male mice feminized by continuous infusion of growth hormone (GH). We identified 71,264 hypersensitive sites, with 1,284 showing robust sex-related differences. Continuous GH infusion suppressed the vast majority of male-specific sites and induced a subset of female-specific sites in male livers. We also identified broad genomic regions (up to ∼100 kb) showing sex-dependent hypersensitivity and similar patterns of GH responses. We found a strong association of sex-specific sites with sex-specific transcription; however, a majority of sex-specific sites were >100 kb from sex-specific genes. By analyzing sequence motifs within regulatory regions, we identified two known regulators of liver sexual dimorphism and several new candidates for further investigation. This approach can readily be applied to mapping condition-specific regulatory sites in mammalian tissues under a wide variety of physiological conditions.
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Chia DJ, Rotwein P. Defining the epigenetic actions of growth hormone: acute chromatin changes accompany GH-activated gene transcription. Mol Endocrinol 2010; 24:2038-49. [PMID: 20702579 DOI: 10.1210/me.2010-0234] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Many of the long-term physiological effects of GH require hormone-mediated changes in gene expression. The transcription factor signal transducer and activator of transcription 5b (Stat5b) plays a critical role in the actions of GH on growth and metabolism by regulating a large number of GH-dependent genes by incompletely understood mechanisms. Here we have assessed the impact of GH-initiated and Stat5b-mediated signaling on the chromatin landscape of hormone-regulated genes in the liver of pituitary-deficient young adult male rats. In the absence of GH there was minimal ongoing transcription at the Socs2, Cish, Igfals, and Spi 2.1 promoters, minimal occupancy of Stat5b at proximal promoter sites, and relatively closed chromatin, as evidenced by low levels of core histone acetylation. In contrast, transcriptionally silent Igf1 promoter 1 appeared poised to be activated, based on binding of coactivators p300 and Med1/Trap220, high levels of histone acetylation, and the presence of RNA polymerase II. GH treatment led to a 8- to 20-fold rise in transcriptional activity of all five genes within 30-60 min and was accompanied by binding of Stat5b to the proximal Socs2, Cish, Igfals, and Spi 2.1 promoters and to seven distal Igf1 Stat5b elements, by enhanced histone acetylation at all five promoters, by recruitment of RNA polymerase II to the Socs2, Cish, Igfals, and Spi 2.1 promoters, and by loss of the transcriptional repressor Bcl6 from Socs2, Cish, and Igfals Stat5b sites, but not from two Igf1 Stat5b domains. We conclude that GH actions induce rapid and dramatic changes in hepatic chromatin at target promoters and propose that the chromatin signature of Igf1 differs from other GH-and Stat5b-dependent genes.
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Affiliation(s)
- Dennis J Chia
- Department of Pediatrics, Oregon Health & Science University, Portland Oregon 97239-3098, USA
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30
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Ajibade DV, Dhawan P, Fechner AJ, Meyer MB, Pike JW, Christakos S. Evidence for a role of prolactin in calcium homeostasis: regulation of intestinal transient receptor potential vanilloid type 6, intestinal calcium absorption, and the 25-hydroxyvitamin D(3) 1alpha hydroxylase gene by prolactin. Endocrinology 2010; 151:2974-84. [PMID: 20463051 PMCID: PMC2903940 DOI: 10.1210/en.2010-0033] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Increased calcium transport has been observed in vitamin D-deficient pregnant and lactating rats, indicating that another factor besides 1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) is involved in intestinal calcium transport. To investigate prolactin as a hormone involved in calcium homeostasis, vitamin D-deficient male mice were injected with 1,25(OH)(2)D(3), prolactin, or prolactin + 1,25(OH)(2)D(3). Prolactin alone (1 microg/g body weight 48, 24, and 4 h before termination) significantly induced duodenal transient receptor potential vanilloid type 6 (TRPV6) mRNA (4-fold) but caused no change in calbindin-D(9k). Combined treatment with 1,25(OH)(2)D(3) and prolactin resulted in an enhancement of the 1,25(OH)(2)D(3) induction of duodenal TRPV6 mRNA, calbindin-D(9k) mRNA, and an induction of duodenal calcium transport [P < 0.05 compared with 1,25(OH)(2)D(3) alone]. Because lactation is associated with an increase in circulating 1,25(OH)(2)D(3), experiments were done to determine whether prolactin also has a direct effect on induction of 25-hydroxyvitamin D(3) 1alpha hydroxylase [1alpha(OH)ase]. Using AOK B-50 cells cotransfected with the prolactin receptor and the mouse 1alpha(OH)ase promoter -1651/+22 cooperative effects between prolactin and signal transducer and activator of transcription 5 were observed in the regulation of 1alpha(OH)ase. In addition, in prolactin receptor transfected AOK B-50 cells, prolactin treatment (400 ng/ml) and signal transducer and activator of transcription 5 significantly induced 1alpha(OH)ase protein as determined by Western blot analysis. Thus, prolactin, by multiple mechanisms, including regulation of vitamin D metabolism, induction of TRPV6 mRNA, and cooperation with 1,25(OH)(2)D(3) in induction of intestinal calcium transport genes and intestinal calcium transport, can act as an important modulator of vitamin D-regulated calcium homeostasis.
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Affiliation(s)
- Dare V Ajibade
- Department of Biochemistry and Molecular Biology, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103, USA
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31
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Chia DJ, Varco-Merth B, Rotwein P. Dispersed Chromosomal Stat5b-binding elements mediate growth hormone-activated insulin-like growth factor-I gene transcription. J Biol Chem 2010; 285:17636-47. [PMID: 20378540 DOI: 10.1074/jbc.m110.117697] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis regulates somatic growth during childhood and orchestrates tissue repair throughout the life span. Recently described inactivating mutations in Stat5b in humans with impaired growth have focused attention on this transcription factor as a key agent linking GH-stimulated signals to IGF-I gene expression, and several putative Stat5b sites have been identified in the IGF-I gene. Here, we define and characterize potential GH- and Stat5b-activated chromosomal enhancers that can regulate IGF-I gene transcription. Of 89 recognizable Stat5 sequences in 200 kb centering on the rat IGF-I gene, 22 resided within conserved regions and/or were identical among different species. Only 15 of these sites, organized into 7 distinct domains, were found to bind Stat5b by quantitative chromatin immunoprecipitation assays in liver chromatin of rats, but only after acute GH treatment. These sites could bind Stat5b in vitro, and individual domains could mediate GH- and Stat5b-stimulated IGF-I promoter activity in cultured cells. Further analyses revealed that four Stat5b domains possessed chromatin signatures of enhancers, including binding of co-activators p300 and Med1, and RNA polymerase II. These modifications preceded GH-stimulated recruitment of Stat5b, as did lysine 4 monomethylation of histone H3, which was enriched in 6/7 Stat5b-binding elements. In contrast, histone acetylation was induced by GH but was limited to Stat5b binding domains found within the IGF-I transcription unit. We conclude that GH stimulates recruitment of Stat5b to multiple dispersed regions within the igf1 locus, including several with properties consistent with long range transcriptional enhancers that collectively regulate GH-activated IGF-I gene transcription.
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Affiliation(s)
- Dennis J Chia
- Department of Pediatrics, Oregon Health & Science University,Portland, Oregon 97239-3098, USA
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Wauthier V, Sugathan A, Meyer RD, Dombkowski AA, Waxman DJ. Intrinsic sex differences in the early growth hormone responsiveness of sex-specific genes in mouse liver. Mol Endocrinol 2010; 24:667-78. [PMID: 20150183 PMCID: PMC2840812 DOI: 10.1210/me.2009-0454] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 12/30/2009] [Indexed: 11/19/2022] Open
Abstract
Sex differences in liver gene expression are dictated by sex differences in circulating GH profiles. Presently, the pituitary hormone dependence of mouse liver gene expression was investigated on a global scale to discover sex-specific early GH response genes that could contribute to sex-specific regulation of downstream GH targets and to ascertain whether intrinsic sex differences characterize hepatic responses to plasma GH stimulation. Global RNA expression analysis identified two distinct classes of sex-specific mouse liver genes: genes subject to positive regulation (class I) and genes subject to negative regulation by pituitary hormones (class II). Genes activated or repressed in hypophysectomized (Hypox) mouse liver within 30-90 min of GH pulse treatment at a physiological dose were identified as putative direct targets of GH action (early response genes). Intrinsic sex differences in the GH responsiveness of a subset of these early response genes were observed. Notably, 45 male-specific genes, including five encoding transcriptional regulators that may mediate downstream sex-specific transcriptional responses, were induced by GH within 30 min in Hypox male but not Hypox female mouse liver. The early GH response genes were enriched in 29 male-specific targets of the transcription factor myocyte enhancer factor 2, whose activation in hepatic stellate cells is associated with liver fibrosis leading to hepatocellular carcinoma, a male-predominant disease. Thus, the rapid activation by GH pulses of certain sex-specific genes is modulated by intrinsic sex-specific factors, which may be associated with prior hormone exposure (epigenetic mechanisms) or genetic factors that are pituitary-independent, and could contribute to sex differences in predisposition to liver cancer or other hepatic patho-physiologies.
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Affiliation(s)
- Valerie Wauthier
- Division of Cell and Molecular Biology, Department of Biology, Boston University, Boston, Massachusetts 02215, USA
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Chia DJ, Young JJ, Mertens AR, Rotwein P. Distinct alterations in chromatin organization of the two IGF-I promoters precede growth hormone-induced activation of IGF-I gene transcription. Mol Endocrinol 2010; 24:779-89. [PMID: 20160126 DOI: 10.1210/me.2009-0430] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Many of the physiological actions of GH are mediated by IGF-I, a secreted 70-residue peptide whose gene expression is induced by GH in the liver and other tissues via mechanisms that remain incompletely characterized but depend on the transcription factor Stat5b. Here we investigate the chromatin landscape of the IGF-I gene in the liver of pituitary-deficient young adult male rats and assess the impact of a single systemic GH injection. Despite minimal ongoing transcription in the absence of GH, both IGF-I promoters appear to reside in open chromatin environments, at least as inferred from relatively high levels of acetylation of core histones H3 and H4 when compared with adjacent intergenic DNA and from enhanced trimethylation of histone H3 at lysine 4. This landscape of open chromatin may reflect maturation of the liver. Surprisingly, in the absence of hormone, IGF-I promoter 1 appears poised to be activated, as evidenced by the presence of the transcriptional coactivator p300 and recruitment of RNA polymerase (Pol) II into a preinitiation complex. By contrast, chromatin surrounding IGF-I promoter 2 is devoid of both p300 and RNA Pol II. Systemic GH treatment causes an approximately 15-fold increase in transcription from each IGF-I promoter within 60 min of hormone administration, leading to a sustained accumulation of IGF-I mRNA. The coordinated induction of both IGF-I promoters by GH is accompanied by hyperacetylation of histones H3 and H4 in promoter-associated chromatin, a decline in monomethylation at lysine 4 of histone H3, and recruitment of RNA Pol II to IGF-I promoter 2. We conclude that GH actions induce rapid and dramatic changes in hepatic chromatin at the IGF-I locus and activate IGF-I gene transcription in the liver by distinct promoter-specific mechanisms: at promoter 1, GH causes RNA Pol II to be released from a previously recruited paused preinitiation complex, whereas at promoter 2, hormone treatment facilitates recruitment and then activation of RNA Pol II to initiate transcription.
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Affiliation(s)
- Dennis J Chia
- Department of Pediatrics, Oregon Health and Science University, Portland, Oregon 97239, USA
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Nicolson TJ, Mellor HR, Roberts RRA. Gender differences in drug toxicity. Trends Pharmacol Sci 2010; 31:108-14. [PMID: 20117848 DOI: 10.1016/j.tips.2009.12.001] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Revised: 11/16/2009] [Accepted: 12/01/2009] [Indexed: 11/27/2022]
Abstract
Clinical data suggest that gender dimorphic profiles are emerging in terms of both drug efficacy and adverse drug reactions (ADRs). With an increasing emphasis on individualised therapies and the need to prevent drug attrition there is a compelling need to understand the molecular basis for gender dimorphic profiles in ADRs and the consequences. Classes of agents exhibiting gender-based variation in pharmaceutical efficacy and toxicity include anaesthetics, HIV-1 therapies and antiarrhythmic drugs. Body weight differences are often cited as a reason for differences in drug pharmacokinetics and subsequent toxicity. However, some studies accounted for these factors and still found significance suggesting that dosage versus body weight does not explain the outcome. Here, we present an overview of current understanding of gender-specific drug toxicity and present rational molecular explanations for these adverse events. There is mounting evidence in support of hormonal effects underpinning the majority of the ADR differences observed between the sexes.
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Affiliation(s)
- Tamara J Nicolson
- General Toxicology Sciences, Safety Assessment UK, AstraZeneca R&D, Alderley Park, Macclesfield, Cheshire, SK10 4TG, UK.
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35
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Meyer RD, Laz EV, Su T, Waxman DJ. Male-specific hepatic Bcl6: growth hormone-induced block of transcription elongation in females and binding to target genes inversely coordinated with STAT5. Mol Endocrinol 2009; 23:1914-26. [PMID: 19797429 PMCID: PMC2775936 DOI: 10.1210/me.2009-0242] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 08/03/2009] [Indexed: 01/21/2023] Open
Abstract
The transcriptional repressor Bcl6 is a male-specific rat liver gene product and one of 24 early GH-response genes encoding DNA-binding proteins. Presently, the sex specificity of Bcl6 was shown to emerge at puberty, when hepatic Bcl6 mRNA was induced in males and repressed in females by the female plasma GH profile. Hepatic Bcl6 mRNA was increased to near-normal male levels in hypophysectomized females and was extinguished in intact males given a continuous GH infusion (female-like GH pattern). Bcl6 was also repressed in adult male somatostatin-deficient mice, where plasma GH profiles are female like. Hepatic Bcl6 RNA was rapidly down-regulated by GH pulse treatment, both in hypophysectomized male rats and in primary rat hepatocytes. Bcl6 was substantially induced in female mice deficient in hepatic signal transducer and activator of transcription (STAT)5a/STAT5b, suggesting that these STAT transcriptional mediators of GH signaling repress Bcl6. Indeed, STAT5 was bound to Bcl6 STAT5-binding region-B, previously associated with Bcl6 repression, in both male and female liver chromatin. STAT5 also bound to Bcl6 region-A in male chromatin but only during a plasma GH pulse. Analysis of primary transcripts (heterogeneous nuclear RNA) across the Bcl6 gene revealed a novel mechanism of GH-dependent sex specificity, with two apparent blocks in Bcl6 transcription elongation seen in female liver and in continuous GH-treated male liver, one early in intron 4 and one in exon 5, which together reduced transcription beyond exon 5 more than 300-fold. Finally, Bcl6 was bound to a subset of STAT5-binding sites in male liver chromatin, including a Socs2 STAT5-binding site where Bcl6 binding increased substantially between plasma GH pulses, i.e. when STAT5 binding was low. Bcl6 and STAT5 binding are thus inversely coordinated by the endogenous pulses of pituitary GH release, suggesting this male-specific transcriptional repressor modulates hepatic GH signaling to select STAT5 target genes.
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Affiliation(s)
- Rosana D Meyer
- Division of Cell and Molecular Biology, Department of Biology, Boston University, Boston, Massachusetts 02215, USA
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36
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Waxman DJ, Holloway MG. Sex differences in the expression of hepatic drug metabolizing enzymes. Mol Pharmacol 2009; 76:215-28. [PMID: 19483103 DOI: 10.1124/mol.109.056705] [Citation(s) in RCA: 513] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Sex differences in pharmacokinetics and pharmacodynamics characterize many drugs and contribute to individual differences in drug efficacy and toxicity. Sex-based differences in drug metabolism are the primary cause of sex-dependent pharmacokinetics and reflect underlying sex differences in the expression of hepatic enzymes active in the metabolism of drugs, steroids, fatty acids and environmental chemicals, including cytochromes P450 (P450s), sulfotransferases, glutathione transferases, and UDP-glucuronosyltransferases. Studies in the rat and mouse liver models have identified more than 1000 genes whose expression is sex-dependent; together, these genes impart substantial sexual dimorphism to liver metabolic function and pathophysiology. Sex differences in drug metabolism and pharmacokinetics also occur in humans and are due in part to the female-predominant expression of CYP3A4, the most important P450 catalyst of drug metabolism in human liver. The sexually dimorphic expression of P450s and other liver-expressed genes is regulated by the temporal pattern of plasma growth hormone (GH) release by the pituitary gland, which shows significant sex differences. These differences are most pronounced in rats and mice, where plasma GH profiles are highly pulsatile (intermittent) in male animals versus more frequent (nearly continuous) in female animals. This review discusses key features of the cell signaling and molecular regulatory mechanisms by which these sex-dependent plasma GH patterns impart sex specificity to the liver. Moreover, the essential role proposed for the GH-activated transcription factor signal transducer and activator of transcription (STAT) 5b, and for hepatic nuclear factor (HNF) 4alpha, as mediators of the sex-dependent effects of GH on the liver, is evaluated. Together, these studies of the cellular, molecular, and gene regulatory mechanisms that underlie sex-based differences in liver gene expression have provided novel insights into the physiological regulation of both xenobiotic and endobiotic metabolism.
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Affiliation(s)
- David J Waxman
- Division of Cell and Molecular Biology, Department of Biology, Boston University, Boston, MA 02215, USA.
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