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Zhang H, Meyer KD, Zhang L. Fetal exposure to cocaine causes programming of Prkce gene repression in the left ventricle of adult rat offspring. Biol Reprod 2008; 80:440-8. [PMID: 18945988 DOI: 10.1095/biolreprod.108.072983] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Previous studies demonstrated that maternal cocaine administration caused a significant decrease in protein kinase C epsilon (PRKCE) abundance in the left ventricle and an increase in susceptibility of the heart to ischemic injury in adult male offspring. The present study tested the hypothesis that epigenetic modification has a key role in cocaine-mediated programming of cardiac Prkce gene repression. Pregnant Sprague-Dawley rats were administered saline or cocaine (30 mg/kg/day i.p.) from Days 15 to 21 of gestational age, and hearts of 3-mo-old adult offspring were studied. Cocaine exposure significantly decreased Prkce mRNA levels in the left ventricle of male but not female offspring. CpG dinucleotides identified in Bhlhb2, Pparg, E2f, and Egr1 binding sites at the Prkce gene promoter were densely methylated in males and females and were unaffected by cocaine exposure. In contrast, methylation of CpGs in the two Sp1 binding sites (-346 and -268) was low and was significantly increased by cocaine exposure in male offspring. In females, methylation of the Sp1 binding site at -268 but not -346 was increased. Reporter gene assays showed that both Sp1 binding sites had a strong stimulatory role in Prkce gene activity. Methylation of the Sp1 binding sites significantly decreased SP1 binding to the Prkce promoter. Cocaine exposure did not affect nuclear SP1 protein levels but decreased the SP1 binding affinity to its binding site at -268. The results demonstrate an epigenetic mechanism of DNA methylation in programming of cardiac Prkce gene repression, linking fetal cocaine exposure and pathophysiological consequences in the heart of adult male offspring in a gender-dependent manner.
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Affiliation(s)
- Haitao Zhang
- Center for Perinatal Biology, Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, California, USA
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102
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Intergenerational programming of impaired nephrogenesis and hypertension in rats following maternal protein restriction during pregnancy. Br J Nutr 2008; 101:1020-30. [PMID: 18778527 DOI: 10.1017/s0007114508057607] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Associations between birth weight and CVD in adult life are supported by experiments showing that undernutrition in fetal life programmes blood pressure. In rats, the feeding of a maternal low-protein (MLP) diet during gestation programmes hypertension. The present study aimed to assess the potential for a nutritional insult to impact across several generations. Pregnant female Wistar (F0) rats were fed a control (CON; n 10) or MLP (n 10) diet throughout gestation. At delivery all animals were fed a standard laboratory chow diet. At 10 weeks of age, F1 generation offspring were mated to produce a second generation (F2) without any further dietary change. The same procedure produced an F3 generation. Blood pressure in all generations was determined at 4, 6 and 8 weeks of age and nephron number was determined at 10 weeks of age. F1 generation MLP-exposed offspring exhibited raised (P < 0.001) systolic blood pressure (male 143 (sem 4) mmHg; female 141 (sem 4) mmHg) compared with CON animals (male 132 (sem 3) mmHg; female 134 (sem 4) mmHg). Raised blood pressure and reduced nephron number was also noted in the F2 generation (P < 0.001) and this intergenerational transmission occurred via both the maternal and paternal lines, as all three possible offspring crosses (MLP x CON, CON x MLP and MLP x MLP) were hypertensive (132 (sem 3) mmHg) compared with CON animals (CON x CON; 123 (sem 2) mmHg). No effect was noted in the F3 generation. It is concluded that fetal protein restriction may play a critical role in determining blood pressure and overall disease risk in a subsequent generation.
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103
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Yang W, Shaw GM, Carmichael SL, Rasmussen SA, Waller DK, Pober BR, Anderka M. Nutrient intakes in women and congenital diaphragmatic hernia in their offspring. ACTA ACUST UNITED AC 2008; 82:131-8. [PMID: 18181217 DOI: 10.1002/bdra.20436] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Congenital diaphragmatic hernia (CDH) is a severe birth defect where there is an opening in the diaphragm through which a portion of the abdominal contents protrudes into the thoracic cavity. The etiologies of CDH remain unknown, although experimental animal data suggest dietary factors might play a role. This study examined whether maternal nutrient intakes were associated with delivering infants with CDH. METHODS We analyzed infants with isolated CDH who were born from 1997 to 2003 and recruited into the National Birth Defects Prevention Study (NBDPS), a multisite, population-based case-control study. Exposure data were obtained from telephone interviews, which were completed within 24 months after delivery, and were available for 377 case mothers and 5,008 control mothers. A food frequency questionnaire was used to derive nutrient intakes during the year before pregnancy. RESULTS A crude OR of 0.6 (95% CI: 0.3-1.0) was observed for higher intake of choline. Elevated ORs (1.4 to 1.7) were found for lower intakes of choline, cysteine, methionine, and protein. Among women who took vitamin supplements, higher intakes of B vitamins (i.e., folate, vitamin B1, B2, B6, and B12), minerals (i.e., calcium, iron, magnesium, and zinc), and vitamin E were inversely associated with CDH (ORs from 0.7-0.3). Moreover, among women who did not take vitamin supplements, lower intakes of calcium, retinol, selenium, vitamin B12, and vitamin E had positive associations with CDH (ORs from 1.4 to 2.1). CONCLUSIONS Our observations contribute to a limited body of evidence suggesting a woman's periconceptional diet might be associated with CDH in her offspring.
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Affiliation(s)
- Wei Yang
- March of Dimes, California Research Division, Oakland, California 94609, USA.
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104
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Epigenetic regulation of human buccal mucosa mitochondrial superoxide dismutase gene expression by diet. Br J Nutr 2008; 101:743-9. [DOI: 10.1017/s0007114508047685] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The impact of nutrition on the epigenetic machinery has increasingly attracted interest. The aim of the present study was to demonstrate the effects of various diets on methylation and gene expression. The antioxidative enzyme mitochondrial superoxide dismutase (MnSOD) was chosen as the model system because epigenetic regulation has been previously shown in cell lines for this gene. Promoter methylation and gene expression of MnSOD in buccal swabs from three sample groups were analysed. The three groups included: (1) forty vegetarians (aged 20–30 years); (2) age-matched omnivores; (3) elderly omnivores (aged>85 years). A 3-fold increase in the expression of the MnSOD gene was associated with decreased CpG methylation of the analysed promoter region in the vegetarian group compared with the age-matched omnivores group. Expression and promoter methylation of the MnSOD gene in elderly omnivores showed no significant differences compared with younger omnivores. In accordance with previous findings in various tissues, DNA global methylation was found to be significantly higher (30 %) in buccal swabs of younger subjects (independent of the diet), than in those of elderly omnivores. In the control experiment which was designed to verify the findings of the human buccal swab studies, the Caco-2 cell line was treated with zebularine. Results of the control study showed a 6-fold increase of MnSOD expression, an approximately 40 % decreased methylation of specified CpG in the MnSOD promoter and a 50 % reduction of global DNA methylation. These results indicate that diet affects the epigenetic regulation of human MnSOD.
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105
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McGowan PO, Meaney MJ, Szyf M. Diet and the epigenetic (re)programming of phenotypic differences in behavior. Brain Res 2008; 1237:12-24. [PMID: 18694740 DOI: 10.1016/j.brainres.2008.07.074] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 07/16/2008] [Accepted: 07/17/2008] [Indexed: 12/12/2022]
Abstract
Phenotypic diversity is shaped by both genetic and epigenetic mechanisms that program tissue specific patterns of gene expression. Cells, including neurons, undergo massive epigenetic reprogramming during development through modifications to chromatin structure, and by covalent modifications of the DNA through methylation. There is evidence that these changes are sensitive to environmental influences such as maternal behavior and diet, leading to sustained differences in phenotype. For example, natural variations in maternal behavior in the rat that influence stress reactivity in offspring induce long-term changes in gene expression, including in the glucocorticoid receptor, that are associated with altered histone acetylation, DNA methylation, and NGFI-A transcription factor binding. These effects can be reversed by early postnatal cross-fostering, and by pharmacological manipulations in adulthood, including Trichostatin A (TSA) and L-methionine administration, that influence the epigenetic status of critical loci in the brain. Because levels of methionine are influenced by diet, these effects suggest that diet could contribute significantly to this behavioral plasticity. Recent data suggest that similar mechanisms could influence human behavior and mental health. Epidemiological data suggest indeed that dietary changes in methyl contents could affect DNA methylation and gene expression programming. Nutritional restriction during gestation could affect epigenetic programming in the brain. These findings provide evidence for a stable yet dynamic epigenome capable of regulating phenotypic plasticity through epigenetic programming.
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Affiliation(s)
- Patrick O McGowan
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
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106
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Mason JB, Choi SW, Liu Z. Other one-carbon micronutrients and age modulate the effects of folate on colorectal carcinogenesis. Nutr Rev 2008; 66 Suppl 1:S15-7. [DOI: 10.1111/j.1753-4887.2008.00058.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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107
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Liu Z, Choi SW, Crott JW, Smith DE, Mason JB. Multiple B-vitamin inadequacy amplifies alterations induced by folate depletion in p53 expression and its downstream effector MDM2. Int J Cancer 2008; 123:519-25. [PMID: 18498130 DOI: 10.1002/ijc.23599] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Folate is required for biological methylation and nucleotide synthesis, aberrations of which are thought to be the mechanisms that enhance colorectal carcinogenesis produced by folate inadequacy. These functions of folate also depend on the availability of other B-vitamins that participate in "one-carbon metabolism," including B2, B6 and B12. Our study therefore investigated whether combined dietary restriction of these vitamins amplifies aberrations in the epigenetic and genetic integrity of the p53 gene that is induced by folate depletion alone. Ninety-six mice were group pair-fed diets with different combinations of B-vitamin depletion over 10 weeks. DNA and RNA were extracted from epithelial cells isolated from the colon. Within the hypermutable region of p53 (exons 5-8), DNA strand breaks were induced within exons 6 and 8 by folate combined with B2, B6 and B12 restriction (p < 0.05); such effects were not significantly induced by mild folate depletion alone. Similarly, a minor degree of hypomethylation of exon 6 produced by isolated folate depletion was significantly amplified (p < or = 0.05) by simultaneous depletion of all 4 B-vitamins. Furthermore, the expression of p53 and MDM2 were significantly decreased (p < or = 0.05) by the combined depletion state but not by folate depletion alone. These data indicate that inadequacies of other 1-carbon vitamins may amplify aberrations of the p53 gene induced by folate depletion alone, implying that concurrent inadequacies in several of these vitamins may have added tumorigenic potential beyond that observed with isolated folate depletion.
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Affiliation(s)
- Zhenhua Liu
- Vitamins and Carcinogenesis Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA.
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108
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Loke KY, Lin JBY, Mabel DY. 3rd College of Paediatrics and Child Health Lecture – The Past, the Present and the Shape of Things to Come…. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2008. [DOI: 10.47102/annals-acadmedsg.v37n5p429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The growth trends of Singapore children spanning 5 decades are reviewed, based on 8 anthropometric studies from 1957 till 2002. The heights of pre-school children and school age children appear to have optimised according to their genetic potential, but the weights and body mass indices of children still appear to be increasing from 6 to 18 years for both sexes, probably as a consequence of increasing affluence. This trend is reflected in the increasing obesity prevalence in school children over the past 30 years, and the concomitant increased morbidity associated with the metabolic syndrome, necessitates further research into the causes of obesity. Barker’s hypothesis first suggested that changes in the intra-uterine environment can cause fetal adaptations which persist into adulthood, and are responsible for many chronic diseases of adult life. More recently, intense research in the field of epigenetics suggests that the environment can also influence the phenotype through gene expression, through modification of DNA methylation and histones which, in turn, influences gene expression. The challenge for the future is to determine if there are clear epigenetic changes, which are responsible for the increased prevalence of childhood and adolescent obesity, and whether these changes are transmitted through generations. Unravelling these epigenetic mechanisms may be the key to the prevention of obesity and the metabolic syndrome.
Key words: Body mass index, Epigenetics, Height, Weight
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109
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Abstract
Nutrigenomics represents a shift of nutrition research from epidemiology and physiology to molecular biology and genetics. Nutrigenomics seeks to understand nutrition influences on homeostasis, the mechanism of genetic predispositions for diseases, to identify the genes influencing risk of diet related diseases. This review presents somein vitromodels applicable in nutrigenomic studies, and discuses the use of animal models, their advantages and limitations and relevance for human situation.In vitroandin vivomodels are suitable for performance of DNA microarrays, proteomic and transcriptomic analyses.In vitromodels (intracellular organelles and suborganellar compartments, cell cultures, or tissue samples/cultures) give insight in metabolic pathways and responses to test stimuli on cellular and molecular levels. Animal models allow evaluation of the biological significance of the effects recordedin vitroand testing of the hypothesis on how a specific factor affects specific species under specific circumstances. Therefore, the evaluation of the data in relation to human organism should be done carefully, considering the species differences. The use ofin vitroandin vivomodels is likely to continue as the effects of nutrition on health and disease cannot be fully explained without understanding of nutrients action at nuclear level and their role in the intra- and intercellular signal transduction. Through advances in cell and molecular biology (including genomic and proteomic), the use of these models should become more predictively accurate. However, this predictive value relies on an underpinning knowledge of the advantages and limitations of the model in nutrigenomic research as in other fields of biomedical research.
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110
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Nag N, Ward B, Berger-Sweeney JE. Nutritional factors in a mouse model of Rett syndrome. Neurosci Biobehav Rev 2008; 33:586-92. [PMID: 18479749 DOI: 10.1016/j.neubiorev.2008.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 03/07/2008] [Accepted: 03/19/2008] [Indexed: 11/17/2022]
Abstract
Environmental factors such as nutrition and housing can influence behavioral and anatomical characteristics of several neurological disorders, including Rett syndrome (RTT). RTT is associated with mutations in the X-linked gene encoding MeCP2, a transcriptional repressor that binds methylated DNA. While direct genetic intervention in humans is impossible at this time, motor and cognitive deficits in RTT may be ameliorated through manipulations of epigenetic/environmental factors. For example, studies in rodents suggest that choline nutrient supplementation during critical periods of brain development enhances cholinergic neurotransmission, alters neuronal size and distribution, and facilitates performance of memory and motoric tasks. Recent work in a mouse model of RTT shows that enhancing maternal nutrition through choline supplementation improves both anatomical and behavioral symptoms in the mutant offspring. We describe here cellular and molecular mechanisms that may underlie this specific enhancement and may provide more general insights into mechanisms underlying gene-environment interactions in neurological disorders.
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Affiliation(s)
- Nupur Nag
- Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, United States
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111
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Abstract
The purpose of this paper was to selectively review the literature on the role of epigenetics in mental illnesses. Aberrant epigenetic regulation has been clearly implicated in the aetiology of some human illnesses. In recent years a growing body of evidence has highlighted the possibility that epigenetics may also play a key role in the origins and expression of mental disorders. Epigenetic phenomena may help explain some of the complexity of mental illnesses and provide a basis for discovering novel pharmacological targets to treat these disorders.
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112
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Liu Z, Choi SW, Crott JW, Keyes MK, Jang H, Smith DE, Kim M, Laird PW, Bronson R, Mason JB. Mild depletion of dietary folate combined with other B vitamins alters multiple components of the Wnt pathway in mouse colon. J Nutr 2007; 137:2701-8. [PMID: 18029487 DOI: 10.1093/jn/137.12.2701] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Preclinical and clinical studies suggest that diminished folate status increases the risk of colorectal carcinogenesis. However, many biochemical functions of folate are dependent on the adequate availability of other 1-carbon nutrients, including riboflavin, vitamin B-6, and vitamin B-12. Aberrations in the Wnt pathway are thought to play an important role in human colorectal cancers. This study therefore investigated if mild depletion of folate combined with depletion of riboflavin, vitamin B-6, and vitamin B-12 could induce alterations in the Wnt pathway in the colonic mucosa. Ninety-six mice were pair-fed diets with different combinations of B vitamin depletion for 10 wk. Genomic DNA methylation and uracil misincorporation were measured by LC/MS and GC/MS. Gene-specific methylation, strand breaks, and expressions were measured by real-time PCR and immunoblotting. Proliferation and apoptosis were determined by immunohistochemistry. DNA strand breaks within the Apc mutation cluster region were induced by folate depletion combined with inadequacies of riboflavin, vitamin B-6, and vitamin B-12 (P < 0.05), but such effects were not induced by folate depletion alone. Similarly, minor changes in the expression of Apc, beta-catenin, and cyclin D1 produced by mild folate depletion were significantly magnified by multiple vitamin depletion. Apoptosis, which can be suppressed by increased Wnt-signaling, was attenuated by the combined deficiency state (P < 0.05) but not by singlet or doublet deficiencies. These findings indicate that a mild depletion of folate that is of insufficient magnitude by itself to induce alterations in components of the Wnt pathway may produce such effects when present in conjunction with mild inadequacies of other 1-carbon nutrients.
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Affiliation(s)
- Zhenhua Liu
- Vitamins and Carcinogenesis Laboratory, Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA
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113
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Abstract
Extensive human epidemiologic and animal model data indicate that during critical periods of prenatal and postnatal mammalian development, nutrition and other environmental stimuli influence developmental pathways and thereby induce permanent changes in metabolism and chronic disease susceptibility. The biologic mechanisms underlying this "developmental origins hypothesis" are poorly understood. This review focuses on the likely involvement of epigenetic mechanisms in the developmental origins of health and disease (DOHaD). We describe permanent effects of transient environmental influences on the developmental establishment of epigenetic gene regulation and evidence linking epigenetic dysregulation with human disease. We propose a definition of "epigenetic epidemiology" and delineate how this emerging field provides a basis from which to explore the role of epigenetic mechanisms in DOHaD. We suggest strategies for future human epidemiologic studies to identify causal associations between early exposures, long-term changes in epigenetic regulation, and disease, which may ultimately enable specific early-life interventions to improve human health.
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Affiliation(s)
- Robert A Waterland
- Department of Pediatrics, USDA Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX, USA.
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114
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Junien C, Nathanielsz P. Report on the IASO Stock Conference 2006: early and lifelong environmental epigenomic programming of metabolic syndrome, obesity and type II diabetes. Obes Rev 2007; 8:487-502. [PMID: 17949354 DOI: 10.1111/j.1467-789x.2007.00371.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Now that analysis of the organization of the human genome sequence is reaching completion, studies of the finely tuned chromatin epigenetic networks, DNA methylation and histone modifications, are required to determine how the same DNA sequence generates different cells, lineages and organs, i.e. the phenotype. Maternal nutrition, behaviour and metabolic disturbances as well as other environmental factors have been shown to have major effects on these epigenetic processes, potentially affecting the predisposition of offspring to obesity and related adult disorders. The March 2006 Stock Conference considered the latest evidence from studies in the field of obesity and other related areas that elucidate mechanisms by which the environment can modify gene expression and the resulting individual phenotype. Presentations included evaluation of the molecular basis of epigenetic memory and the nature of relevant sequence targets, windows of susceptibility, and maternal dietary and behavioural factors that determine epigenetic changes. Imprinted genes, age and tissue-related exposures, transgenerational and potential interventions were also discussed. In summary, it is clear that epigenetic alterations can no longer be ignored in evaluations of the causes of obesity and its associated disorders. There is a need for systematic large-scale epigenetic studies of obesity, employing appropriate strategies and techniques and appropriately chosen environmental factors in critical spatio-temporal windows.
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Affiliation(s)
- C Junien
- Inserm U 781, Clinique Maurice Lamy, Hôpital Necker Enfants Malades 149 rue de Sèvres, Paris, France.
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115
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Kovacheva VP, Mellott TJ, Davison JM, Wagner N, Lopez-Coviella I, Schnitzler AC, Blusztajn JK. Gestational choline deficiency causes global and Igf2 gene DNA hypermethylation by up-regulation of Dnmt1 expression. J Biol Chem 2007; 282:31777-88. [PMID: 17724018 DOI: 10.1074/jbc.m705539200] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During gestation there is a high demand for the essential nutrient choline. Adult rats supplemented with choline during embryonic days (E) 11-17 have improved memory performance and do not exhibit age-related memory decline, whereas prenatally choline-deficient animals have memory deficits. Choline, via betaine, provides methyl groups for the production of S-adenosylmethionine, a substrate of DNA methyltransferases (DNMTs). We describe an apparently adaptive epigenomic response to varied gestational choline supply in rat fetal liver and brain. S-Adenosylmethionine levels increased in both organs of E17 fetuses whose mothers consumed a choline-supplemented diet. Surprisingly, global DNA methylation increased in choline-deficient animals, and this was accompanied by overexpression of Dnmt1 mRNA. Previous studies showed that the prenatal choline supply affects the expression of multiple genes, including insulin-like growth factor 2 (Igf2), whose expression is regulated in a DNA methylation-dependent manner. The differentially methylated region 2 of Igf2 was hypermethylated in the liver of E17 choline-deficient fetuses, and this as well as Igf2 mRNA levels correlated with the expression of Dnmt1 and with hypomethylation of a regulatory CpG within the Dnmt1 locus. Moreover, mRNA expression of brain and liver Dnmt3a and methyl CpG-binding domain 2 (Mbd2) protein as well as cerebral Dnmt3l was inversely correlated to the intake of choline. Thus, choline deficiency modulates fetal DNA methylation machinery in a complex fashion that includes hypomethylation of the regulatory CpGs within the Dnmt1 gene, leading to its overexpression and the resultant increased global and gene-specific (e.g. Igf2) DNA methylation. These epigenomic responses to gestational choline supply may initiate the long term developmental changes observed in rats exposed to varied choline intake in utero.
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Affiliation(s)
- Vesela P Kovacheva
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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116
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Gallou-Kabani C, Vigé A, Gross MS, Junien C. Nutri-epigenomics: lifelong remodelling of our epigenomes by nutritional and metabolic factors and beyond. Clin Chem Lab Med 2007; 45:321-7. [PMID: 17378726 DOI: 10.1515/cclm.2007.081] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The phenotype of an individual is the result of complex interactions between genotype, epigenome and current, past and ancestral environment, leading to lifelong remodelling of our epigenomes. Various replication-dependent and -independent epigenetic mechanisms are involved in developmental programming, lifelong stochastic and environmental deteriorations, circadian deteriorations, and transgenerational effects. Several types of sequences can be targets of a host of environmental factors and can be associated with specific epigenetic signatures and patterns of gene expression. Depending on the nature and intensity of the insult, the critical spatiotemporal windows and developmental or lifelong processes involved, these epigenetic alterations can lead to permanent changes in tissue and organ structure and function, or to reversible changes using appropriate epigenetic tools. Given several encouraging trials, prevention and therapy of age- and lifestyle-related diseases by individualised tailoring of optimal epigenetic diets or drugs are conceivable. However, these interventions will require intense efforts to unravel the complexity of these epigenetic, genetic and environment interactions and to evaluate their potential reversibility with minimal side effects.
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Affiliation(s)
- Catherine Gallou-Kabani
- 1. Inserm, AP-HP, Université Paris-Descartes, Faculté de Médecine, Hôpital Necker-Enfants Malades, Inserm U781, Paris, France
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117
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Cutfield WS, Hofman PL, Mitchell M, Morison IM. Could epigenetics play a role in the developmental origins of health and disease? Pediatr Res 2007; 61:68R-75R. [PMID: 17413843 DOI: 10.1203/pdr.0b013e318045764c] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Following Barker's observations of an association between birth size and later adult diseases, considerable efforts have been made to define the characteristics of low birth weight groups in childhood. In this review, the phenotypic and biochemical characteristics during childhood of three low birth weight groups are summarized: children born following inviter fertilization (IVF), small for gestational age (SGA), or very premature. Each of these groups is likely to have been exposed to an adverse environment at different developmental stages. The triggers and mechanisms leading to programmed changes in growth, development, and metabolism of these groups of children have yet to be identified. Epigenetics has been proposed as a potential mechanism for these programmed changes through environmentally induced changes in gene expression. Data from animal models in which environmental, particularly nutritional, manipulation leads to changes in DNA methylation are presented. The relevance of these animal studies to IVF, SGA, and very premature children are discussed as are potential candidate genes that may have undergone epigenetic modification to alter growth and metabolism.
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Affiliation(s)
- Wayne S Cutfield
- Liggins Institute, National Research Centre for Growth and Development, University of Auckland, Department of Pediatrics, New Zealand.
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118
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Freilinger M, Kalisch D, Muehl A, Haas O, Moritz A, Bodamer O. Methylation status in females with rett syndrome. J Child Neurol 2007; 22:635-8. [PMID: 17690074 DOI: 10.1177/0883073807302616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The authors studied methionine and creatine metabolism in females with Rett syndrome. Plasma metabolites (including methionine, homocysteine, guanidinoacetate) and urine creatine/creatinine ratios in 29 females with Rett syndrome were within the age-appropriate range. Although the authors have not been able to identify any abnormalities, it can be speculated that patients with Rett syndrome may benefit from dietary intervention to increase the supply of labile methyl groups to affected tissues.
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119
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Ahmed FE. Colorectal cancer epigenetics: the role of environmental factors and the search for molecular biomarkers. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2007; 25:101-54. [PMID: 17558783 DOI: 10.1080/10590500701399184] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
This review presents an evenhanded evaluation of the role of epigenetics in the development of colorectal cancer, and investigates the extent of environmental influences on modulating this disease. Advances in our understanding of chromatin structure, histone modification, transcriptional activity and DNA methylation have lead to an integrated approach to the role of epigenetics in carcinogenesis. Epigenetic mechanisms appear to permit response of individuals to environment through change in gene expression and are involved in inactivating one of the two X chromosomes in women. Epigenetic changes play an important role in development and can also arise stochastically as individuals age. Because epigenetic alterations are potentially reversible, thereby allowing malignant cells to revert to the normal state, there is potential to develop effective strategies to prevent or even reverse this curable cancer. Moreover, because the methylation status of a specific sequence or the pattern of methylation across the genome can now be measured accurately, molecular biomarkers of screening, diagnosis, prognosis, prediction of treatment and those related to risk assessment can be developed using sophisticated molecular genetic technologies. Although in many cases a high sensitivity and specificity of the detection assays has been achieved, there still remains ample room for improvement in areas of sample preparation, assay design and marker selection.
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Affiliation(s)
- Farid E Ahmed
- Department of Radiation Oncology, Leo W. Jenkins Cancer Center, The Brody School of Medicine, East Carolina University, Greenville, North Carolina 27858, USA.
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Zhang H, Darwanto A, Linkhart TA, Sowers LC, Zhang L. Maternal cocaine administration causes an epigenetic modification of protein kinase Cepsilon gene expression in fetal rat heart. Mol Pharmacol 2007; 71:1319-28. [PMID: 17202284 DOI: 10.1124/mol.106.032011] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Protein kinase Cepsilon (PKCepsilon) plays a pivotal role in cardioprotection during cardiac ischemia and reperfusion injury. Recent studies demonstrated that prenatal cocaine exposure caused a decrease in PKCepsilon expression and increased heart susceptibility to ischemic injury in adult offspring, suggesting an in utero programming of PKCepsilon gene expression pattern in the heart. The present investigation aimed to elucidate whether an epigenetic mechanism, DNA methylation, accounts for cocaine-mediated repression of the PKCepsilon gene in the heart. Pregnant rats were administered either saline or cocaine intraperitoneally (15 mg/kg) twice daily from days 15 to 20 of gestational age, and term fetal hearts were studied. Cocaine treatment significantly decreased PKCepsilon mRNA and protein levels in the heart. CpG dinucleotides found in cAMP response element-binding protein (CREB), CREB/c-Jun1, and CREB/c-Jun2 binding sites at the proximal promoter region of the PKCepsilon gene were densely methylated and were not affected by cocaine. In contrast, methylation of CpGs in the activator protein 1 (AP-1) binding sites was low but was significantly increased by cocaine. Reporter gene assays showed that the AP-1 binding site played a strong stimulatory role of PKCepsilon gene transcription. Methylation of the AP-1 binding sites significantly decreased AP-1 binding to the PKCepsilon promoter. Supershift analyses implicated c-Jun homodimers binding to the AP-1 binding sites. Cocaine did not affect nuclear c-Jun levels or the binding of c-Jun to the unmethylated AP-1 binding sites. The results indicate a role for DNA methylation in cocaine-mediated PKCepsilon gene repression in the developing heart and suggest an epigenetic mechanism affecting this gene linked with vulnerability of ischemic injury in the heart of adult offspring.
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Affiliation(s)
- Haitao Zhang
- Center for Perinatal Biology, Department of Pharmacology and Physiology, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
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121
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Environment and Gene Expression. Integr Med (Encinitas) 2007. [DOI: 10.1016/b978-1-4160-2954-0.50007-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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122
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Enaw JOE, Zhu H, Yang W, Lu W, Shaw GM, Lammer EJ, Finnell RH. CHKA and PCYT1A gene polymorphisms, choline intake and spina bifida risk in a California population. BMC Med 2006; 4:36. [PMID: 17184542 PMCID: PMC1770928 DOI: 10.1186/1741-7015-4-36] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Accepted: 12/21/2006] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Neural tube defects (NTDs) are among the most common of all human congenital defects. Over the last two decades, accumulating evidence has made it clear that periconceptional intake of folic acid can significantly reduce the risk of NTD affected pregnancies. This beneficial effect may be related to the ability of folates to donate methyl groups for critical physiological reactions. Choline is an essential nutrient and it is also a methyl donor critical for the maintenance of cell membrane integrity and methyl metabolism. Perturbations in choline metabolism in vitro have been shown to induce NTDs in mouse embryos. METHODS This study investigated whether single nucleotide polymorphisms (SNPs) in human choline kinase A (CHKA) gene and CTP:phosphocholine cytidylytransferase (PCYT1A) gene were risk factors for spina bifida. Fluorescence-based allelic discrimination analysis was performed for the two CHKA intronic SNPs hCV1562388 (rs7928739) and hCV1562393, and PCYT1A SNP rs939883 and rs3772109. The study population consisted of 103 infants with spina bifida and 338 non-malformed control infants who were born in selected California counties in the period 1989-1991. RESULTS The CHKA SNP hCV1562388 genotypes with at least one C allele were associated with a reduced risk of spina bifida (odds ratio = 0.60, 95%CI = 0.38-0.94). The PCYT1A SNP rs939883 genotype AA was associated with a twofold increased risk of spina bifida (odds ratio = 1.89, 95% CI = 0.97-3.67). These gene-only effects were not substantially modified by analytic consideration to maternal periconceptional choline intake. CONCLUSION Our analyses showed genotype effects of CHKA and PCYT1A genes on spina bifida risk, but did not show evidence of gene-nutrient interactions. The underlying mechanisms are yet to be resolved.
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Affiliation(s)
- James O Ebot Enaw
- Center for Environmental and Genetic Medicine, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas 77030, USA
| | - Huiping Zhu
- Center for Environmental and Genetic Medicine, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas 77030, USA
| | - Wei Yang
- California Birth Defects Monitoring Program, Berkeley, CA, USA
| | - Wei Lu
- Center for Environmental and Genetic Medicine, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas 77030, USA
| | - Gary M Shaw
- California Birth Defects Monitoring Program, Berkeley, CA, USA
| | - Edward J Lammer
- Children's Hospital Oakland Research Institute, Oakland, CA, USA
| | - Richard H Finnell
- Center for Environmental and Genetic Medicine, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas 77030, USA
- Center for Environmental and Rural Health, Texas A&M University, College Station, Texas 77843, USA
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123
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Moon HW, Kim TY, Oh BR, Min HC, Cho HI, Bang SM, Lee JH, Yoon SS, Lee DS. MTHFR 677CC/1298CC genotypes are highly associated with chronic myelogenous leukemia: a case-control study in Korea. Leuk Res 2006; 31:1213-7. [PMID: 17156840 DOI: 10.1016/j.leukres.2006.10.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 09/18/2006] [Accepted: 10/19/2006] [Indexed: 10/23/2022]
Abstract
Methylenetetrahydrofolate reductase (MTHFR) is an enzyme involved in folate metabolism and DNA methylation. Studies on MTHFR polymorphism in leukemia have largely focused on the protective role of MTHFR polymorphism in acute lymphoblastic leukemia (ALL). We evaluated the C677T and A1298C polymorphisms using the TaqMan allelic discrimination assay in various malignancies. The study population included 115 subjects with chronic myelogenous leukemia (CML), 200 with acute myelogenous leukemia (AML), 196 with multiple myeloma (MM) and 434 healthy control subjects. The frequency of 1298CC was statistically significantly higher in subjects with CML than that of the controls (OR=5.12, 95% CI: 1.75-14.9, P-value=.003). Of note, the frequencies of 677CC/1298CC genotype were statistically significantly higher in subjects with CML, AML and MM than that of the controls (OR=8.8, 3.5, 3.83, P-value=.002, 0.036, 0.023, respectively). Our results demonstrate that the MTHFR 1298CC homozygote variant is strongly associated with an increased risk of CML, while MTHFR C677T does not significantly affect the risk of CML. Moreover, we demonstrated that MTHFR 677CC and 1298CC genotype might have combined effect on risk of CML, AML and MM and it is inferred that the A1298C may play a different role in carcinogenesis, depending on the types of organs involved, the types of disease entities and the genotype of C677T.
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MESH Headings
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Case-Control Studies
- Child
- Child, Preschool
- DNA Primers
- Female
- Genetic Predisposition to Disease
- Genotype
- Humans
- Infant
- Korea
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/enzymology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myeloid, Acute/genetics
- Male
- Methylenetetrahydrofolate Reductase (NADPH2)/genetics
- Middle Aged
- Multiple Myeloma/genetics
- Polymorphism, Genetic/genetics
- Risk Factors
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Affiliation(s)
- Hee Won Moon
- Department of Laboratory Medicine, Ewha Womans University College of Medicine, Seoul, South Korea
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124
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Romero R, Espinoza J, Gotsch F, Kusanovic JP, Friel LA, Erez O, Mazaki-Tovi S, Than NG, Hassan S, Tromp G. The use of high-dimensional biology (genomics, transcriptomics, proteomics, and metabolomics) to understand the preterm parturition syndrome. BJOG 2006; 113 Suppl 3:118-35. [PMID: 17206980 PMCID: PMC7062297 DOI: 10.1111/j.1471-0528.2006.01150.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
High-dimensional biology (HDB) refers to the simultaneous study of the genetic variants (DNA variation), transcription (messenger RNA [mRNA]), peptides and proteins, and metabolites of an organ, tissue, or an organism in health and disease. The fundamental premise is that the evolutionary complexity of biological systems renders them difficult to comprehensively understand using only a reductionist approach. Such complexity can become tractable with the use of "omics" research. This term refers to the study of entities in aggregate. The current nomenclature of "omics" sciences includes genomics for DNA variants, transcriptomics for mRNA, proteomics for proteins, and metabolomics for intermediate products of metabolism. Another discipline relevant to medicine is pharmacogenomics. The two major advances that have made HDB possible are technological breakthroughs that allow simultaneous examination of thousands of genes, transcripts, and proteins, etc., with high-throughput techniques and analytical tools to extract information. What is conventionally considered hypothesis-driven research and discovery-driven research (through "omic" methodologies) are complementary and synergistic. Here we review data which have been derived from: 1) genomics to examine predisposing factors for preterm birth; 2) transcriptomics to determine changes in mRNA in reproductive tissues associated with preterm labour and preterm prelabour rupture of membranes; 3) proteomics to identify differentially expressed proteins in amniotic fluid of women with preterm labour; and 4) metabolomics to identify the metabolic footprints of women with preterm labour likely to deliver preterm and those who will deliver at term. The complementary nature of discovery science and HDB is emphasised.
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Affiliation(s)
- R Romero
- Perinatology Research Branch, Intramural Division, National Institute of Child Health and Human Development, NIH/DHHS, Hutzel Women's Hospital, Bethesda, MD 20892, USA.
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125
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Waterland RA. Epigenetic mechanisms and gastrointestinal development. J Pediatr 2006; 149:S137-42. [PMID: 17212956 DOI: 10.1016/j.jpeds.2006.06.064] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2006] [Revised: 02/27/2006] [Accepted: 06/01/2006] [Indexed: 01/05/2023]
Abstract
This review considers the hypothesis that nutrition during infancy affects developmental epigenetics in the gut, causing metabolic imprinting of gastrointestinal (GI) structure and function. Fundamentals of epigenetic gene regulation are reviewed, with an emphasis on the epigenetic mechanism of DNA methylation. Recent data indicate that transient nutritional and other stimuli during critical periods of prenatal and early postnatal development can affect the establishment or developmental maturation of gene-specific DNA methylation, thereby inducing permanent changes in gene expression. Although epigenetic processes are clearly involved in postnatal mammalian GI development, we currently know very little about these mechanisms. Data indicating that epigenetic gene regulation plays an important role in GI development and pathology are reviewed, and suggestions for future research in this area are offered.
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Affiliation(s)
- Robert A Waterland
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
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126
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Haslberger A, Varga F, Karlic H. Recursive causality in evolution: a model for epigenetic mechanisms in cancer development. Med Hypotheses 2006; 67:1448-54. [PMID: 16844314 DOI: 10.1016/j.mehy.2006.05.047] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2006] [Revised: 05/23/2006] [Accepted: 05/23/2006] [Indexed: 01/30/2023]
Abstract
Interactions between adaptative and selective processes are illustrated in the model of recursive causality as defined in Rupert Riedl's systems theory of evolution. One of the main features of this theory also termed as theory of evolving complexity is the centrality of the notion of 'recursive' or 'feedback' causality - 'the idea that every biological effect in living systems, in some way, feeds back to its own cause'. Our hypothesis is that "recursive" or "feedback" causality provides a model for explaining the consequences of interacting genetic and epigenetic mechanisms which are known to play a key role in development of cancer. Epigenetics includes any process that alters gene activity without changes of the DNA sequence. The most important epigenetic mechanisms are DNA-methylation and chromatin remodeling. Hypomethylation of so-called oncogenes and hypermethylation of tumor suppressor genes appear to be critical determinants of cancer. Folic acid, vitamin B12 and other nutrients influence the function of enzymes that participate in various methylation processes by affecting the supply of methyl groups into a variety of molecules which may be directly or indirectly associated with cancerogenesis. We present an example from our own studies by showing that vitamin D3 has the potential to de-methylate the osteocalcin-promoter in MG63 osteosarcoma cells. Consequently, a stimulation of osteocalcin synthesis can be observed. The above mentioned enzymes also play a role in development and differentiation of cells and organisms and thus illustrate the close association between evolutionary and developmental mechanisms. This enabled new ways to understand the interaction between the genome and environment and may improve biomedical concepts including environmental health aspects where epigenetic and genetic modifications are closely associated. Recent observations showed that methylated nucleotides in the gene promoter may serve as a target for solar UV-induced mutations of the p53 tumor suppressor gene. This illustrates the close interaction of genetic and epigenetic mechanisms in cancerogenesis resulting from changes in transcriptional regulation and its contribution to a phenotype at the micro- or macroevolutionary level. Above-mentioned interactions of genetic and epigenetic mechanisms in oncogenesis defy explanation by plain linear causality, things like the continuing adaptability of complex systems. They can be explained by the concept of recursive causality and has introduced molecular biology into the realm of cognition science and systems theory: based on the notion of so-called feedback- or recursive causality a model for epigenetic mechanisms with relevance for oncology and biomedicine is provided.
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Affiliation(s)
- A Haslberger
- Ludwig Boltzmann Institute for Leukemia Research and Hematology, Hanusch Hospital, Heinrich Collinstrasse 30, and Vienna Ecology Center, University of Vienna, Austria
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127
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Fukagawa NK. Sparing of methionine requirements: evaluation of human data takes sulfur amino acids beyond protein. J Nutr 2006; 136:1676S-1681S. [PMID: 16702339 DOI: 10.1093/jn/136.6.1676s] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The intimate relation between amino acids and protein and nitrogen requirements is well recognized. Nutrition research has focused on the capacity of food to meet the need for nitrogen and indispensable amino acids (IAA) and led to the conclusion that the quality, not just the quantity, of protein is critical. This is especially relevant in regard to the sulfur amino acids (SAA) methionine and cysteine because of the increased understanding of their relation to chronic diseases (e.g., cardiovascular disease, dementia, cirrhosis), immunomodulation, DNA transcription, and RNA translation. Considerable effort has been expended to determine whether and to what extent cysteine can spare the requirement for the IAA methionine. In vivo studies in humans generally concur that the dietary requirement of the SAA ranges between 13 and 16 mg.kg(-1).d(-1), but how much can be met by cysteine relative to methionine remains controversial. This review examines the current status of in vivo estimates of methionine and cysteine requirements in human adults and considers needs beyond what is necessary for protein synthesis. Factors influencing the utilization of methionine and cysteine, especially those conditions that lead to toxicity on the one hand or beneficial effects on the other, are discussed. Data on alternative dietary sources of methyl groups (e.g., betaine, choline, phosphatidylcholine, S-adenosylmethionine, S-methylmethionine) or sulfur (e.g., N-acetylcysteine or L-2-oxothiazolidine-4-carboxylic acid) support a role for the SAA "beyond protein." Other pathways may influence the specific requirement for methionine and/or cysteine, especially when the person is challenged by disease, inadequate availability of food, or environmental stress.
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Affiliation(s)
- Naomi K Fukagawa
- Department of Medicine and General Clinical Research Center, University of Vermont College of Medicine, Burlington, Vermont 05405, USA.
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128
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Polesskaya OO, Aston C, Sokolov BP. Allele C-specific methylation of the 5-HT2A receptor gene: evidence for correlation with its expression and expression of DNA methylase DNMT1. J Neurosci Res 2006; 83:362-73. [PMID: 16358338 DOI: 10.1002/jnr.20732] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Differential DNA methylation has been suggested to contribute to differential activity of alleles C and T and thereby to genetic associations between the C/T(102) polymorphism in the 5-HT2A receptor gene (5HT2AR) and psychiatric disorders. We surveyed methylation in two CpG sites, which are specific to allele C. The majority of allele C-specific CpG sites were methylated in human temporal cortex and peripheral leukocytes and levels of methylation varied between individuals. Levels of methylation in the promoter correlated significantly with the expression of 5HT2AR. Methylation of allele C-specific CpG sites in the first exon correlated significantly with the expression of DNA methylase 1 (DNMT1) but not S-adenosylhomocysteine hydrolase (AHCY). These findings support the hypothesis that allele-specific DNA methylation is involved in regulation of 5HT2AR expression, influencing expression differences between alleles C and T.
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Affiliation(s)
- Oxana O Polesskaya
- Molecular Neurobiology Branch, National Institute on Drug Abuse, NIH, DHHS, Baltimore, Maryland 21224, USA
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129
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Affiliation(s)
- Kelly S Swanson
- Department of Animal Sciences, College of Agriculture, Consumer and Environmental Sciences, University of Illinois, Urbana, IL 61801, USA
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130
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Weaver ICG, Champagne FA, Brown SE, Dymov S, Sharma S, Meaney MJ, Szyf M. Reversal of maternal programming of stress responses in adult offspring through methyl supplementation: altering epigenetic marking later in life. J Neurosci 2006; 25:11045-54. [PMID: 16306417 PMCID: PMC6725868 DOI: 10.1523/jneurosci.3652-05.2005] [Citation(s) in RCA: 585] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Stress responses in the adult rat are programmed early in life by maternal care and associated with epigenomic marking of the hippocampal exon 1(7) glucocorticoid receptor (GR) promoter. To examine whether such epigenetic programming is reversible in adult life, we centrally infused the adult offspring with the essential amino acid L-methionine, a precursor to S-adenosyl-methionine that serves as the donor of methyl groups for DNA methylation. Here we report that methionine infusion reverses the effect of maternal behavior on DNA methylation, nerve growth factor-inducible protein-A binding to the exon 1(7) promoter, GR expression, and hypothalamic-pituitary-adrenal and behavioral responses to stress, suggesting a causal relationship among epigenomic state, GR expression, and stress responses in the adult offspring. These results demonstrate that, despite the inherent stability of the epigenomic marks established early in life through behavioral programming, they are potentially reversible in the adult brain.
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Affiliation(s)
- Ian C G Weaver
- Douglas Hospital Research Center, Montréal, Québec H4H 1R3, Canada
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131
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Lee HK, Park KS, Cho YM, Lee YY, Pak YK. Mitochondria-Based Model for Fetal Origin of Adult Disease and Insulin Resistance. Ann N Y Acad Sci 2006; 1042:1-18. [PMID: 15965040 DOI: 10.1196/annals.1338.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Insulin resistance has been recognized as the fundamental underlying metabolic defect in the pathogenesis of metabolic syndrome, a clustering of cardiovascular risk factors such as diabetes, hypertension, dyslipidemia, and obesity. Recent studies established that mitochondrial dysfunction is involved in insulin resistance in general and fetal origin of this state in particular. Because genes are the fundamental molecular basis of inheritance--and thus the cornerstones of evolution--a model explaining insulin resistance is based at the gene level at best. Since a certain mtDNA polymorphism, 16189T>C, is associated with insulin resistance, mtDNA has to be a basic component of the gene-based model. We developed a mitochondria-based model that explains insulin resistance in terms of quantitative and qualitative change of the mitochondrion and its DNA. This model can accommodate several important hypotheses, such as thrifty genotype hypothesis, thrifty phenotype hypothesis, fetal insulin hypothesis, contribution of metabolic imprinting by epigenetic changes, and many other features associated with insulin resistance. We will discuss mechanisms that indicate why the perturbed initial condition of mitochondrial function should lead to the reduced insulin sensitivity.
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Affiliation(s)
- Hong Kyu Lee
- Department of Internal Medicine, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Gu, Seoul, 110-744, Korea.
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132
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Waterland RA, Dolinoy DC, Lin JR, Smith CA, Shi X, Tahiliani KG. Maternal methyl supplements increase offspring DNA methylation atAxin fused. Genesis 2006; 44:401-6. [PMID: 16868943 DOI: 10.1002/dvg.20230] [Citation(s) in RCA: 321] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Transient environmental exposures during mammalian development can permanently alter gene expression and metabolism by influencing the establishment of epigenetic gene regulatory mechanisms. The genomic characteristics that confer such epigenetic plasticity upon specific loci, however, have not been characterized. Methyl donor supplementation of female mice before and during pregnancy permanently increases DNA methylation at the viable yellow agouti (A(vy)) metastable epiallele in the offspring. The current study tested whether another murine metastable epiallele, axin fused (Axin(Fu)), similarly exhibits epigenetic plasticity to maternal diet. We found that methyl donor supplementation of female mice before and during pregnancy increased DNA methylation at Axin(Fu) and thereby reduced by half the incidence of tail kinking in Axin(Fu)/+ offspring. The hypermethylation was tail-specific, suggesting a mid-gestation effect. Our results indicate that stochastic establishment of epigenotype at metastable epialleles is, in general, labile to methyl donor nutrition, and such influences are not limited to early embryonic development.
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Affiliation(s)
- Robert A Waterland
- Department of Pediatrics, Baylor College of Medicine, USDA Children's Nutrition Research Center, Houston, Texas 77030, USA.
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133
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Lee YY, Park KS, Pak YK, Lee HK. The role of mitochondrial DNA in the development of type 2 diabetes caused by fetal malnutrition. J Nutr Biochem 2005; 16:195-204. [PMID: 15808323 DOI: 10.1016/j.jnutbio.2004.11.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2004] [Revised: 10/12/2004] [Accepted: 11/05/2004] [Indexed: 01/06/2023]
Abstract
Epidemiological studies have revealed strong and reproducible links between indices of poor fetal growth and susceptibility to the development of glucose intolerance and insulin resistance syndrome in adult life. To explain these associations, the thrifty phenotype hypothesis has been proposed. Mitochondrial DNA abnormalities have been known to cause insulin deficiency, insulin resistance and diabetes mellitus. In this review, we propose that mitochondrial dysfunction is a link between malnutrition during early life and disease in adult life. The potential mechanism for mitochondrial dysfunction will be focused on availability of the taurine and nucleotides, and imprinting on the genes.
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Affiliation(s)
- Yun Yong Lee
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-744, South Korea
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134
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Williams AC, Ramsden DB. Nicotinamide homeostasis: a xenobiotic pathway that is key to development and degenerative diseases. Med Hypotheses 2005; 65:353-62. [PMID: 15922112 DOI: 10.1016/j.mehy.2005.01.042] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Accepted: 01/27/2005] [Indexed: 12/17/2022]
Abstract
Monkeys and man are very closely related genetically. Yet intellectually there are big differences and they suffer from a broad range of different diseases. For example, monkeys do not get Parkinson's or Alzheimer's disease. The former is surprising given that both get parkinsonism from MPTP poisoning and the latter initially less surprising as the cortex predominantly affected in Alzheimer's never developed as fully in the monkey. Man is an omnivore whilst other primates are predominantly herbivores. The one primate who was almost wholly carnivorous was Neanderthal man who became extinct. Red meat has a high content of Nicotinamide, Choline, and methyl donors. The enzyme NNMT converts nicotinamide to N-methyl-nicotinamide using SAM as the methyl donor. It is not present to any degree in herbivores. It has recently been shown to be present in human brain and up regulated in Parkinson's disease. Omnivores presumably need it for nicotinamide homeostasis but the production of N-methyl-nicotinamide will also be beneficial as it will reduce the export of Choline from neurones. Both will aid brain growth and development. However, as N-methyl-nicotinamide resembles MPTP it could cause parkinsonism later in life for man but not monkeys as they would be predicted not to have as much NNMT. Humans with a diet low in Nicotinamide,Choline or methyl donors early in life and low enzyme activity may be prone to Alzheimer's as their brain and therefore its reserves may never have developed as fully. The possession of NNMT plus a diet rich in Nicotinamide, Choline and methyl providers may explain many of the advantages but also the disadvantages of the human condition. One prediction is that a diet rich in these micronutrients whilst young will improve brain development and reduce the risk of Alzheimer's but that a lower dose later in life will reduce the risk of Parkinsonism. A second prediction is that it will become clear that dietary factors including vitamins are signalers and at the head of vital biochemical pathways. A time point will be reached when errors emerge that could not be deleted by evolutionary pressures. Finding and rectifying them will be the key to preventing many common diseases.
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Affiliation(s)
- A C Williams
- Division of Neuroscience, University of Birmingham, Edgbaston, Birminham B15 2 TT, UK.
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135
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Shiota K. DNA methylation profiles of CpG islands for cellular differentiation and development in mammals. Cytogenet Genome Res 2005; 105:325-34. [PMID: 15237220 DOI: 10.1159/000078205] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2003] [Accepted: 12/02/2003] [Indexed: 11/19/2022] Open
Abstract
DNA methylation has been implicated in mammalian development. Transcription units contain CpG islands, but expression of CpG island associated genes in normal tissues was not believed to be controlled by DNA methylation. There are, however, numerous CpG islands containing tissue-dependent and differentially methylated regions (T-DMR), which are potential methylation sites in normal cells and tissues. Genomic scanning which focused on T-DMRs in CpG islands revealed that the DNA methylation profile of each cell/tissue is more complicated than previously considered. Differentiation of cells is associated with both methylation and demethylation, which occur at multiple loci. The epigenetic system characterized by DNA methylation requires cells to memorize gene expression patterns, thus, standardizing cellular phenotypes.
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Affiliation(s)
- K Shiota
- Cellular Biochemistry, Animal Resource Sciences, Veterinary Medical Sciences, University of Tokyo, Tokyo, Japan.
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136
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Scarano MI, Strazzullo M, Matarazzo MR, D'Esposito M. DNA methylation 40 years later: Its role in human health and disease. J Cell Physiol 2005; 204:21-35. [PMID: 15648089 DOI: 10.1002/jcp.20280] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A long path, initiated more than 40 years ago, has led to a deeper understanding of the complexity of gene regulation in eukaryotic genomes. In addition to genetic mechanisms, the imbalance in the epigenetic control of gene expression may profoundly alter the finely tuned machinery leading to gene regulation. Here, we review the impact of the studies on DNA methylation, the "primadonna" in the epigenetic scenario, on the understanding of basic phenomena, such as X inactivation and genomic imprinting. The effect of deregulation of DNA methylation on human health, will be also discussed. Finally, an attempt to predict future directions of this rapidly evolving field has been proposed, with the certainty that, fortunately, science is always better than predictions.
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Affiliation(s)
- Maria Irene Scarano
- Department of Biomorphological and Functional Sciences, University of Naples "Federico II", Naples, Italy.
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137
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Lever M, George PM, Dellow WJ, Scott RS, Chambers ST. Homocysteine, glycine betaine, and N,N-dimethylglycine in patients attending a lipid clinic. Metabolism 2005; 54:1-14. [PMID: 15562374 DOI: 10.1016/j.metabol.2004.07.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We recruited nondiabetic subjects (n = 158) attending a lipid disorders clinic, a subset of whom (n = 46) had established cardiovascular disease. Glycine betaine, N,N-dimethylglycine, and carnitine were measured in fasting plasma and urine samples. The concentrations and excretions were related to known cardiovascular risk factors in multivariate regression models. The relationships between homocysteine and plasma and urinary glycine betaine were highly significant (P < .002), comparable with the known relationships with folate and plasma creatinine. The regression coefficient for plasma glycine betaine was consistently approximately -0.1 in 5 different regression models (3 best-subsets and forward and backward stepwise regression models) for predicting homocysteine using 23 variables. Plasma glycine betaine was higher in males than in females, and the difference was associated with a difference in percentage of body fat. Its concentration included a constant factor of approximately 20 micromol/L that was independent of any of the variables investigated here. In the total group, body fat, homocysteine, and carnitine were significant predictors of plasma glycine betaine. Carnitine, an important betaine that is involved in lipid metabolism positively correlated with both homocysteine and glycine betaine. In our sample, the urinary excretion of glycine betaine was outside the reference range in 14 of the 158 subjects and the betaine fractional clearances were above the reference range in 23 subjects. Fractional clearance correlated strongly with plasma homocysteine (r = 0.50), and this relationship may be stronger in patients with known vascular disease. Urinary loss of glycine betaine may contribute to hyperhomocysteinemia and the development of cardiovascular disease.
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Affiliation(s)
- Michael Lever
- Biochemistry Unit, Canterbury Health Laboratories, PO Box 151, Christchurch, New Zealand
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138
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Dan B, Servais L, Boyd SG, Wagstaff J, Cheron G. From Electrophysiology to Chromatin: A Bottom-Up Approach to Angelman Syndrome. Ann N Y Acad Sci 2004; 1030:599-611. [PMID: 15659843 DOI: 10.1196/annals.1329.070] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Angelman syndrome is one of the most studied human diseases related to a gene that is expressed on the maternal chromosome only in at least some brain cells. It is caused by inactivation of the UBE3A gene in the brain due to various abnormalities of the 15q11-q13 chromosome inherited from the mother. It is characterized by severe developmental delay, seizures, virtual absence of speech, motor impairment, and a particular behavioral phenotype. Studies of cortical, electromyographic and cerebellar electrophysiology in patients with Angelman syndrome and a mouse model revealed unique rhythmic neurophysiological activities in the cerebral cortex, cerebellar cortex, and muscles. The oscillatory patterns may be linked to molecular pathophysiology of the syndrome involving dysregulation of synaptic neurotransmission through UBE3A-related modulation of functional GABAA receptor complexes.
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Affiliation(s)
- Bernard Dan
- Department of Neurology, University Children's Hospital Queen Fabiola, Free University of Brussels, 15 Avenue J.J. Crocq, 1020 Brussels, Belgium.
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139
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Abstract
Betaine is distributed widely in animals, plants, and microorganisms, and rich dietary sources include seafood, especially marine invertebrates ( approximately 1%); wheat germ or bran ( approximately 1%); and spinach ( approximately 0.7%). The principal physiologic role of betaine is as an osmolyte and methyl donor (transmethylation). As an osmolyte, betaine protects cells, proteins, and enzymes from environmental stress (eg, low water, high salinity, or extreme temperature). As a methyl donor, betaine participates in the methionine cycle-primarily in the human liver and kidneys. Inadequate dietary intake of methyl groups leads to hypomethylation in many important pathways, including 1) disturbed hepatic protein (methionine) metabolism as determined by elevated plasma homocysteine concentrations and decreased S-adenosylmethionine concentrations, and 2) inadequate hepatic fat metabolism, which leads to steatosis (fatty accumulation) and subsequent plasma dyslipidemia. This alteration in liver metabolism may contribute to various diseases, including coronary, cerebral, hepatic, and vascular diseases. Betaine has been shown to protect internal organs, improve vascular risk factors, and enhance performance. Databases of betaine content in food are being developed for correlation with population health studies. The growing body of evidence shows that betaine is an important nutrient for the prevention of chronic disease.
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Affiliation(s)
- Stuart A S Craig
- Danisco USA Inc., 440 Saw Mill River Road, Ardsley, NY 10502, USA.
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140
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Waterland RA, Jirtle RL. Early nutrition, epigenetic changes at transposons and imprinted genes, and enhanced susceptibility to adult chronic diseases. Nutrition 2004; 20:63-8. [PMID: 14698016 DOI: 10.1016/j.nut.2003.09.011] [Citation(s) in RCA: 506] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Robert A Waterland
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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141
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Singh SM, Murphy B, O'Reilly RL. Involvement of gene-diet/drug interaction in DNA methylation and its contribution to complex diseases: from cancer to schizophrenia. Clin Genet 2004; 64:451-60. [PMID: 14986824 DOI: 10.1046/j.1399-0004.2003.00190.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Most biological processes, including diseases, involve genetic and non-genetic factors. Also, the realization of a genetic potential may depend on environmental factors by directly affecting the expression of gene(s). Exactly how different environmental factors affect gene expression is not well understood. One of the mechanisms may involve DNA methylation and thereby gene expression. Diet, chemicals, and metals are known to affect DNA methylation and other epigenetic processes but are just beginning to be elucidated. For example, methylation of cytosine(s) in the promoter region could prevent the binding of transcription factors or create binding sites for complexes that deacetylate neighboring histones that in turn compact the chromatin, encouraging a gene to become silent. This article will discuss DNA methylation as an epigenetic mechanism of gene regulation and examine how factors like diet, chemicals, and metals may affect DNA methylation. The effect of alterations in DNA methylation may include aberrant expression of genes or genomes and chromosomal instability, which in turn may contribute to the etiology of complex multifactorial diseases. A similar mechanism is now recognized in a number of cancers. There is also indirect evidence to suggest that methylation could apply to a number of complex diseases, including schizophrenia.
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Affiliation(s)
- S M Singh
- Molecular Genetics Unit, Department of Biology, Division of Medical Genetics, University of Western Ontario, London, Ontario, Canada.
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142
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Shaw GM, Carmichael SL, Yang W, Selvin S, Schaffer DM. Periconceptional dietary intake of choline and betaine and neural tube defects in offspring. Am J Epidemiol 2004; 160:102-9. [PMID: 15234930 DOI: 10.1093/aje/kwh187] [Citation(s) in RCA: 254] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Periconceptional intake of folic acid prevents some neural tube defects (NTDs). Other nutrients may also contribute to NTD etiologies; a likely candidate is choline. Similar to folic acid, choline is involved in one-carbon metabolism for methylation of homocysteine to methionine. The authors investigated whether maternal periconceptional dietary intakes of choline and its metabolite betaine influence NTD risk. Data were derived from a case-control study of fetuses and infants with NTDs among 1989-1991 California births. In-person interviews were conducted with mothers of 424 NTD cases and with mothers of 440 nonmalformed controls. A standard 100-item food frequency questionnaire was used to assess nutrient intake. Dietary intakes of choline were associated with reduced NTD risks. Controlling for intake of supplemental folic acid, dietary folate, dietary methionine, and other covariates did not substantially influence risk estimates for choline. NTD risk estimates were lowest for women whose diets were rich in choline, betaine, and methionine. That is, for women whose intake was above the 75th percentile compared with below the 25th percentile for all three nutrients, the odds ratio was 0.17 (95% confidence interval: 0.04, 0.76). Study findings for dietary components other than folic acid offer additional clues about the complex etiologies of NTDs.
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Affiliation(s)
- Gary M Shaw
- March of Dimes Birth Defects Foundation, California Birth Defects Monitoring Program, Berkeley, CA 94710, USA.
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143
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Abdolmaleky HM, Smith CL, Faraone SV, Shafa R, Stone W, Glatt SJ, Tsuang MT. Methylomics in psychiatry: Modulation of gene-environment interactions may be through DNA methylation. Am J Med Genet B Neuropsychiatr Genet 2004; 127B:51-9. [PMID: 15108180 DOI: 10.1002/ajmg.b.20142] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fine-tuning of neuronal connections during development is regulated through environmental interactions. Some fine-tuning occurs through changes in gene expression and/or epigenetic gene-specific DNA methylation states. DNA methylation occurs by transfer of a methyl group from S-adenosyl methionine to cytosine residues in the dinucleotide sequence CpG. Although CpG sequences spread throughout the genome are usually heavily methylated, those occurring in CpG islands in the promoter regions of genes are less methylated. In most cases, the extent of DNA methylation correlates with the extent of gene inactivation. Other known epigenetic mechanisms include histone deacetylation and chromatin remodeling, RNA inhibition, RNA modification, and DNA rearrangement. Exposure memory expressed as epigenetic DNA modifications allows genomic plasticity and short-term adaptation of each generation to their environment. Environmental factors that affect DNA methylation include diet, proteins, drugs, and hormones. Induced methylation changes may produce altered gene response upon subsequent hormonal stimulation. The gene-specific DNA methylation state may be preserved upon transmission through mitosis and meiosis. An increasing amount of data implicates a role for DNA methylation in multi-factorial psychiatric disorders. For example, L-methionine treatment can exacerbate psychosis; while valproate, a drug producing hypomethylated DNA, reduces such symptoms. Hypermethylation of the promoter region of the RELN gene correlates with reduced gene expression. This gene's protein Reelin, which is necessary for neuronal migration and synaptogenesis, is reduced in schizophrenia and bipolar disorder, suggesting hypermethylation of the promoter region in these disorders. Some evidence implicates methylation of the promoter regions of the DRD2 and HTR2A genes in schizophrenia and mood disorders as well. DNA methylation usually increases with age, although hypomethylation of the promoter region of the amyloid A4 precursor gene during aging may play a role in Alzheimer's disease. More studies are needed to define the role of methylomics and other epigenetic phenomena in the nervous system.
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Affiliation(s)
- Hamid Mostafavi Abdolmaleky
- Department of Psychiatry, Harvard Medical School at Massachusetts Mental Health Center, Boston, Massachusetts 02115, USA
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144
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Abstract
Epigenetics refers to covalent modifications of DNA and core histones that regulate gene activity without altering DNA sequence. To date, the best-characterized DNA modification associated with the modulation of gene activity is methylation of cytosine residues within CpG dinucleotides. Human disorders associated with epigenetic abnormalities include rare imprinting diseases, molar pregnancies, and childhood cancers. Germ cell development and early embryo development are critical times when epigenetic patterns are initiated or maintained. This review focuses on the epigenetic modification DNA methylation and discusses recent progress that has been made in understanding when and how epigenetic patterns are differentially established in the male and female germlines, the mouse, and human disorders associated with abnormalities in epigenetic programming in germ cells and early embryos, as well as genetic and other modulators (e.g. nutrition and drugs) of reproductive epigenetic events.
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Affiliation(s)
- T L J Kelly
- McGill University-Montreal Children's Hospital Research Institute and Department of Paediatrics, McGill University, Montreal, Quebec, Canada
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145
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Ohlsson R, Kanduri C, Whitehead J, Pfeifer S, Lobanenkov V, Feinberg AP. Epigenetic variability and the evolution of human cancer. Adv Cancer Res 2003; 88:145-68. [PMID: 12665055 DOI: 10.1016/s0065-230x(03)88306-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Although the leading dogma for the origin of the diversity in cancer cell subpopulations is based on a stepwise selection and accumulation of genetic changes that allow uncontrollable malignant growth, there is an emerging understanding that the variability of heritable phenotypes in cancer and cancer-prone cells may also involve epigenetic mechanisms. We discuss here experimental data that allow us to postulate that the genome is organized into epigenetic territories with lineage-specific differences in the stringencies of the active and inactive states. Low-stringency epigenetic states are predicted to be closer to mosaicism, or chaos, than high-stringency states. In pathological situations, the result is an epigenetic variability upon which selection mechanisms can act during tumor progression. This view may have significant implications on clinical assessment and prognosis, and also suggests that major factors involved in the resetting and/or maintenance of epigenetic states may serve as new attractive targets for therapeutic interventions.
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Affiliation(s)
- Rolf Ohlsson
- Department of Development and Genetics, Evolution Biology Centre, Uppsala University, S-752 36 Uppsala, Sweden
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146
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Abstract
Girls with Rett syndrome display signs of neuronal dysfunction including mental retardation, seizures, stereotyped movements, and abnormal breathing and autonomic control. Decelerating head growth during infancy might reflect a disorder in production or pruning of neuronal synapses or both. Recent immunocytochemical studies in rodent brain investigating development of MeCP2, the transcription factor mutated in Rett syndrome, suggest that expression is delayed until the time of synapse formation. These findings are consistent with other evidence that Rett syndrome disrupts genetic programs that establish and refine synaptic connections.
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Affiliation(s)
- Michael V Johnston
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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147
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Motiwala T, Ghoshal K, Das A, Majumder S, Weichenhan D, Wu YZ, Holman K, James SJ, Jacob ST, Plass C. Suppression of the protein tyrosine phosphatase receptor type O gene (PTPRO) by methylation in hepatocellular carcinomas. Oncogene 2003; 22:6319-31. [PMID: 14508512 PMCID: PMC3020652 DOI: 10.1038/sj.onc.1206750] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2003] [Revised: 04/23/2003] [Accepted: 04/26/2003] [Indexed: 11/09/2022]
Abstract
A diet lacking folic acid and choline and low in methionine (folate/methyl deficient diet, FMD diet) fed to rats is known to produce preneoplastic nodules (PNNs) after 36 weeks and hepatocellular carcinomas (tumors) after 54 weeks. FMD diet-induced tumors exhibit global hypomethylation and regional hypermethylation. Restriction landmark genome scanning analysis with methylation-sensitive enzyme NotI (RLGS-M) of genomic DNA isolated from control livers, PNNs and tumor tissues was performed to identify the genes that are differentially methylated or amplified during multistage hepatocarcinogenesis. Out of the 1250 genes analysed, 2 to 5 genes were methylated in the PNNs, whereas 5 to 45 genes were partially or completely methylated in the tumors. This analysis also showed amplification of 3 to 12 genes in the primary tumors. As a first step towards identifying the genes methylated in the PNNs and primary hepatomas, we generated a rat NotI-EcoRV genomic library in the pBluescriptKS vector. Here, we describe identification of one methylated and downregulated gene as the rat protein tyrosine phosphatase receptor type O (PTPRO) and one amplified gene as rat C-MYC. Methylation of PTPRO at the NotI site located immediate upstream of the trancription start site in the PNNs and tumors, and amplification of C-MYC gene in the tumors were confirmed by Southern blot analyses. Bisulfite genomic sequencing of the CpG island encompassing exon 1 of the PTPRO gene revealed dense methylation in the PNNs and tumors, whereas it was methylation free in the livers of animals on normal diet. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed significant decrease in the expression of PTPRO in the tumors and in a transplanted rat hepatoma. The expression of PTPRO mRNA in the transplanted hepatoma after demethylation with 5-azacytidine, a potent inhibitor of DNA methyltransferases, further confirmed the role of methylation in PTPRO gene expression. These results demonstrate alteration in methylation profile and expression of specific genes during tumor progression in the livers of rats in response to folate/methyl deficiency, and further implicate the potential role of PTPRO as a novel growth regulatory gene at least in the hepatocellular carcinomas.
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Affiliation(s)
- Tasneem Motiwala
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Kalpana Ghoshal
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Anindita Das
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Sarmila Majumder
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Dieter Weichenhan
- Medizinische Universität zu Lübeck, Institut für Biologie, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Yue-Zhong Wu
- Division of Human Cancer Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Kristen Holman
- Division of Human Cancer Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - S Jill James
- Division of Biochemical Toxicology, Food and Drug administration, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Samson T Jacob
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Christoph Plass
- Division of Human Cancer Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
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148
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Lamprecht SA, Lipkin M. Chemoprevention of colon cancer by calcium, vitamin D and folate: molecular mechanisms. Nat Rev Cancer 2003; 3:601-14. [PMID: 12894248 DOI: 10.1038/nrc1144] [Citation(s) in RCA: 374] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recent findings have indicated that dietary calcium, vitamin D and folate can modulate and inhibit colon carcinogenesis. Supporting evidence has been obtained from a wide variety of preclinical experimental studies, epidemiological findings and a few human clinical trials. Important molecular events and cellular actions of these micronutrients that contribute to their tumour-modulating effects are discussed. They include a complex series of signalling events that affect the structural and functional organization of colon cells.
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Affiliation(s)
- Sergio A Lamprecht
- Strang Cancer Prevention Center and Strang Cancer Research Laboratory at The Rockefeller University, 1230 York Avenue, New York, New York 10021, USA.
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149
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Waterland RA, Jirtle RL. Transposable elements: targets for early nutritional effects on epigenetic gene regulation. Mol Cell Biol 2003; 23:5293-300. [PMID: 12861015 PMCID: PMC165709 DOI: 10.1128/mcb.23.15.5293-5300.2003] [Citation(s) in RCA: 1240] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2003] [Revised: 04/14/2003] [Accepted: 05/08/2003] [Indexed: 12/11/2022] Open
Abstract
Early nutrition affects adult metabolism in humans and other mammals, potentially via persistent alterations in DNA methylation. With viable yellow agouti (A(vy)) mice, which harbor a transposable element in the agouti gene, we tested the hypothesis that the metastable methylation status of specific transposable element insertion sites renders them epigenetically labile to early methyl donor nutrition. Our results show that dietary methyl supplementation of a/a dams with extra folic acid, vitamin B(12), choline, and betaine alter the phenotype of their A(vy)/a offspring via increased CpG methylation at the A(vy) locus and that the epigenetic metastability which confers this lability is due to the A(vy) transposable element. These findings suggest that dietary supplementation, long presumed to be purely beneficial, may have unintended deleterious influences on the establishment of epigenetic gene regulation in humans.
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Affiliation(s)
- Robert A Waterland
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
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150
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Jaenisch R, Bird A. Epigenetic regulation of gene expression: how the genome integrates intrinsic and environmental signals. Nat Genet 2003; 33 Suppl:245-54. [PMID: 12610534 DOI: 10.1038/ng1089] [Citation(s) in RCA: 4149] [Impact Index Per Article: 197.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cells of a multicellular organism are genetically homogeneous but structurally and functionally heterogeneous owing to the differential expression of genes. Many of these differences in gene expression arise during development and are subsequently retained through mitosis. Stable alterations of this kind are said to be 'epigenetic', because they are heritable in the short term but do not involve mutations of the DNA itself. Research over the past few years has focused on two molecular mechanisms that mediate epigenetic phenomena: DNA methylation and histone modifications. Here, we review advances in the understanding of the mechanism and role of DNA methylation in biological processes. Epigenetic effects by means of DNA methylation have an important role in development but can also arise stochastically as animals age. Identification of proteins that mediate these effects has provided insight into this complex process and diseases that occur when it is perturbed. External influences on epigenetic processes are seen in the effects of diet on long-term diseases such as cancer. Thus, epigenetic mechanisms seem to allow an organism to respond to the environment through changes in gene expression. The extent to which environmental effects can provoke epigenetic responses represents an exciting area of future research.
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Affiliation(s)
- Rudolf Jaenisch
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA
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