Tissue-, sex-, and age-specific DNA methylation of rat glucocorticoid receptor gene promoter and insulin-like growth factor 2 imprinting control region

2017 ◽  
Vol 49 (11) ◽  
pp. 690-702 ◽  
Author(s):  
Ogechukwu Brenda Agba ◽  
Ludwig Lausser ◽  
Klaus Huse ◽  
Christoph Bergmeier ◽  
Niels Jahn ◽  
...  

Tissue-, sex-, and age-specific epigenetic modifications such as DNA methylation are largely unknown. Changes in DNA methylation of the glucocorticoid receptor gene ( NR3C1) and imprinting control region (ICR) of IGF2 and H19 genes during the lifespan are particularly interesting since these genes are susceptible to epigenetic modifications by prenatal stress or malnutrition. They are important regulators of development and aging. Methylation changes of NR3C1 affect glucocorticoid receptor expression, which is associated with stress sensitivity and stress-related diseases predominantly occurring during aging. Methylation changes of IGF2/H19 affect growth trajectory and nutrient use with risk of metabolic syndrome. Using a locus-specific approach, we characterized DNA methylation patterns of different Nr3c1 promoters and Igf2/H19 ICR in seven tissues of rats at 3, 9, and 24 mo of age. We found a complex pattern of locus-, tissue-, sex-, and age-specific DNA methylation. Tissue-specific methylation was most prominent at the shores of the Nr3c1 CpG island (CGI). Sex-specific differences in methylation peaked at 9 mo. During aging, Nr3c1 predominantly displayed hypomethylation mainly in females and at shores, whereas hypermethylation occurred within the CGI. Igf2/H19 ICR exhibited age-related hypomethylation occurring mainly in males. Methylation patterns of Nr3c1 in the skin correlated with those in the cortex, hippocampus, and hypothalamus. Skin may serve as proxy for methylation changes in central parts of the hypothalamic-pituitary-adrenal axis and hence for vulnerability to stress- and age-associated diseases. Thus, we provide in-depth insight into the complex DNA methylation changes of rat Nr3c1 and Igf2/H19 during aging that are tissue and sex specific.

2005 ◽  
Vol 7 (2) ◽  
pp. 103-123 ◽  

Early experience permanently alters behavior and physiology. These effects are, in part, mediated by sustained alterations in gene expression in selected brain regions. The critical question concerns the mechanism of these environmental "programming" effects. We examine this issue with an animal model that studies the consequences of variations in mother-infant interactions on the development of individual differences in behavioral and endocrine responses to stress in adulthood. Increased levels of pup licking/grooming by rat mothers in the first week of life alter DNA structure at a glucocorticoid receptor gene promoter in the hippocampus of the offspring. Differences in the DNA methylation pattern between the offspring of high- and low-licking/grooming mothers emerge over the first week of life; they are reversed with cross-fostering; they persist into adulthood; and they are associated with altered histone acetylation and transcription factor (nerve growth factor-induced clone A [NGFIA]) binding to the glucocorticoid receptor promoter. DNA methylation alters glucocorticoid receptor expression through modifications of chromatin structure. Pharmacological reversal of the effects on chromatin structure completely eliminates the effects of maternal care on glucocorticoid receptor expression and hypothalamic-pituitary-adrenal (HPA) responses to stress, thus suggesting a causal relation between the maternally induced, epigenetic modification of the glucocorticoid receptor gene and the effects on stress responses in the offspring. These findings demonstrate that the structural modifications of the DNA can be established through environmental programming and that, in spite of the inherent stability of this epigenomic marker, it is dynamic and potentially reversible.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Blanca Jimeno ◽  
Michaela Hau ◽  
Elena Gómez-Díaz ◽  
Simon Verhulst

Abstract Developmental conditions can impact the adult phenotype via epigenetic changes that modulate gene expression. In mammals, methylation of the glucocorticoid receptor gene Nr3c1 has been implicated as mediator of long-term effects of developmental conditions, but this evidence is limited to humans and rodents, and few studies have simultaneously tested for associations between DNA methylation, gene expression and phenotype. Adverse environmental conditions during early life (large natal brood size) or adulthood (high foraging costs) exert multiple long-term phenotypic effects in zebra finches, and we here test for effects of these manipulations on DNA methylation and expression of the Nr3c1 gene in blood. Having been reared in a large brood induced higher DNA methylation of the Nr3c1 regulatory region in adulthood, and this effect persisted over years. Nr3c1 expression was negatively correlated with methylation at 2 out of 8 CpG sites, and was lower in hard foraging conditions, despite foraging conditions having no effect on Nr3c1 methylation at our target region. Nr3c1 expression also correlated with glucocorticoid traits: higher expression level was associated with lower plasma baseline corticosterone concentrations and enhanced corticosterone reactivity. Our results suggest that methylation of the Nr3c1 regulatory region can contribute to the mechanisms underlying the emergence of long-term effects of developmental conditions in birds, but in our system current adversity dominated over early life experiences with respect to receptor expression.


2000 ◽  
Vol 20 (23) ◽  
pp. 9009-9017 ◽  
Author(s):  
Holger M. Reichardt ◽  
Thorsten Umland ◽  
Anton Bauer ◽  
Oliver Kretz ◽  
Günther Schütz

ABSTRACT Targeted mutagenesis of the glucocorticoid receptor has revealed an essential function for survival and the regulation of multiple physiological processes. To investigate the effects of an increased gene dosage of the receptor, we have generated transgenic mice carrying two additional copies of the glucocorticoid receptor gene by using a yeast artificial chromosome. Interestingly, overexpression of the glucocorticoid receptor alters the basal regulation of the hypothalamo-pituitary-adrenal axis, resulting in reduced expression of corticotropin-releasing hormone and adrenocorticotrope hormone and a fourfold reduction in the level of circulating glucocorticoids. In addition, primary thymocytes obtained from transgenic mice show an enhanced sensitivity to glucocorticoid-induced apoptosis. Finally, analysis of these mice under challenge conditions revealed that expression of the glucocorticoid receptor above wild-type levels leads to a weaker response to restraint stress and a strongly increased resistance to lipopolysaccharide-induced endotoxic shock. These results underscore the importance of tight regulation of glucocorticoid receptor expression for the control of physiological and pathological processes. Furthermore, they may explain differences in the susceptibility of humans to inflammatory diseases and stress, depending on individual prenatal and postnatal experiences known to influence the expression of the glucocorticoid receptor.


2015 ◽  
Vol 45 (16) ◽  
pp. 3393-3410 ◽  
Author(s):  
C. Smart ◽  
G. Strathdee ◽  
S. Watson ◽  
C. Murgatroyd ◽  
R. H. McAllister-Williams

Background.Hopes to identify genetic susceptibility loci accounting for the heritability seen in unipolar depression have not been fully realized. Family history remains the ‘gold standard’ for both risk stratification and prognosis in complex phenotypes such as depression. Meanwhile, the physiological mechanisms underlying life-event triggers for depression remain opaque. Epigenetics, comprising heritable changes in gene expression other than alterations of the nucleotide sequence, may offer a way to deepen our understanding of the aetiology and pathophysiology of unipolar depression and optimize treatments. A heuristic target for exploring the relevance of epigenetic changes in unipolar depression is the hypothalamic–pituitary–adrenal (HPA) axis. The glucocorticoid receptor (GR) gene (NR3C1) has been found to be susceptible to epigenetic modification, specifically DNA methylation, in the context of environmental stress such as early life trauma, which is an established risk for depression later in life.Method.In this paper we discuss the progress that has been made by studies that have investigated the relationship between depression, early trauma, the HPA axis and the NR3C1 gene. Difficulties with the design of these studies are also explored.Results.Future efforts will need to comprehensively address epigenetic natural histories at the population, tissue, cell and gene levels. The complex interactions between the epigenome, genome and environment, as well as ongoing nosological difficulties, also pose significant challenges.Conclusions.The work that has been done so far is nevertheless encouraging and suggests potential mechanistic and biomarker roles for differential DNA methylation patterns in NR3C1 as well as novel therapeutic targets.


2017 ◽  
Vol 35 (11) ◽  
pp. 2276-2286 ◽  
Author(s):  
Sulistyo E. Dwi Putra ◽  
Christoph Reichetzeder ◽  
Martin Meixner ◽  
Karsten Liere ◽  
Torsten Slowinski ◽  
...  

2019 ◽  
Vol 59 (2) ◽  
pp. 264-272 ◽  
Author(s):  
Stefanie J Siller ◽  
Dustin R Rubenstein

Abstract Negative feedback of the vertebrate stress response via the hypothalamic–pituitary–adrenal (HPA) axis is regulated by glucocorticoid receptors in the brain. Epigenetic modification of the glucocorticoid receptor gene (Nr3c1), including DNA methylation of the promoter region, can influence expression of these receptors, impacting behavior, physiology, and fitness. However, we still know little about the long-term effects of these modifications on fitness. To better understand these fitness effects, we must first develop a non-lethal method to assess DNA methylation in the brain that allows for multiple measurements throughout an organism’s lifetime. In this study, we aimed to determine if blood is a viable biomarker for Nr3c1 DNA methylation in two brain regions (hippocampus and hypothalamus) in adult European starlings (Sturnus vulgaris). We found that DNA methylation of CpG sites in the complete Nr3c1 putative promoter varied among tissue types and was lowest in blood. Although we identified a similar cluster of correlated Nr3c1 putative promoter CpG sites within each tissue, this cluster did not show any correlation in DNA methylation among tissues. Additional studies should consider the role of the developmental environment in producing epigenetic modifications in different tissues.


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