Heart disease is the leading cause of death in the United States, with ischemic heart disease a major cause of morbidity and mortality. Yet the molecular mechanisms remain largely elusive. In addition to other risk factors, large epidemiological and animal studies have shown a clear association of fetal stress during the development with increased risk of ischemic heart disease in adulthood. Glucocorticoids play a center role in the response to stress. Our recent studies demonstrated that maternal/fetal hypoxia resulted in a decrease in glucocorticoid receptor (GR) mRNA and protein abundance in fetal hearts that persisted in adult offspring, suggesting in utero epigenetic programming of GR gene repression in the developing heart. The pathophysiological significance of decreased GR expression levels in the heart is highlighted by the findings that demonstrate cardioprotective effects of glucocorticoids in the acute setting of myocardial ischemia and reperfusion injury both in humans and in animals. Our preliminary studies suggested that hypoxia increased GR gene promoter methylation in fetal hearts. DNA methylation is a chief mechanism in epigenetic modification of gene expression patterns. Although methylation of the GR promoter has been reported to occur as function of physiological regulation of the hypothalamic- pituitary-adrenal axis, little is known about the epigenetic regulation of GR gene expression patterns in the developing heart and its functional consequences. The proposed studies will address these major gaps in our knowledge and test the hypothesis that epigenetic repression of glucocorticoid receptor gene in the developing heart results in developmental programming of ischemic-sensitive phenotype in the heart.
Three specific aims are proposed to determine whether: 1) maternal/fetal hypoxia during gestation increases the promoter methylation resulting in GR gene repression in the developing heart, 2) hypoxia has direct causal effects leading to heightened GR promoter methylation and gene repression, and 3) hypoxia-mediated GR gene repression in the developing heart contributes to developmental programming of ischemic-sensitive phenotype in the heart. The overall impact of the proposed studies is that the findings will not only significantly advance our knowledge of molecular mechanisms underlying fetal stress-induced programming of ischemic-sensitive phenotype in the heart and hence improve our understanding of pathophysiology of ischemic heart disease, but they will also provide important original insights into epigenetic mechanisms regulating GR gene expression patterns in a broad field of developmental programming of health and disease, given that glucocorticoids play a common and center role in the stress response.

Public Health Relevance

Heart disease is the leading cause of death in the United States, with ischemic heart disease a major cause of morbidity and mortality. Yet the molecular mechanisms remain largely elusive. Large epidemiological and animal studies have shown a clear association of adverse intrauterine environment with increased risk of ischemic heart disease in adulthood. The proposed studies will provide new insights into the molecular mechanisms in developmental programming of ischemic-sensitive phenotype in the heart, and hence improve our understanding of pathophysiology of ischemic heart disease and may suggest new insights in the development of preventive diagnoses and therapeutic strategies in the treatment of cardiovascular disease.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL118861-01A1
Application #
8632153
Study Section
Special Emphasis Panel (ZRG1-EMNR-H (02))
Program Officer
Schramm, Charlene A
Project Start
2013-12-15
Project End
2017-11-30
Budget Start
2013-12-15
Budget End
2014-11-30
Support Year
1
Fiscal Year
2014
Total Cost
$355,500
Indirect Cost
$130,500
Name
Loma Linda University
Department
Other Basic Sciences
Type
Schools of Medicine
DUNS #
009656273
City
Loma Linda
State
CA
Country
United States
Zip Code
92350
Xiong, Fuxia; Lin, Thant; Song, Minwoo et al. (2016) Antenatal hypoxia induces epigenetic repression of glucocorticoid receptor and promotes ischemic-sensitive phenotype in the developing heart. J Mol Cell Cardiol 91:160-71
Li, Yong; Ma, Qingyi; Halavi, Shina et al. (2016) Fetal stress-mediated hypomethylation increases the brain susceptibility to hypoxic-ischemic injury in neonatal rats. Exp Neurol 275 Pt 1:1-10
Xiao, DaLiao; Wang, Lei; Huang, Xiaohui et al. (2016) Protective Effect of Antenatal Antioxidant on Nicotine-Induced Heart Ischemia-Sensitive Phenotype in Rat Offspring. PLoS One 11:e0150557
Gay, Maresha S; Dasgupta, Chiranjib; Li, Yong et al. (2016) Dexamethasone Induces Cardiomyocyte Terminal Differentiation via Epigenetic Repression of Cyclin D2 Gene. J Pharmacol Exp Ther 358:190-8
Ma, Qingyi; Dasgupta, Chiranjib; Li, Yong et al. (2016) Inhibition of microRNA-210 provides neuroprotection in hypoxic-ischemic brain injury in neonatal rats. Neurobiol Dis 89:202-12
Li, Yong; Ma, Qingyi; Dasgupta, Chiranjib et al. (2016) Inhibition of DNA Methylation in the Developing Rat Brain Disrupts Sexually Dimorphic Neurobehavioral Phenotypes in Adulthood. Mol Neurobiol :
Xia, Shuixiu; Lv, Juanxiu; Gao, Qinqin et al. (2015) Prenatal exposure to hypoxia induced Beclin 1 signaling-mediated renal autophagy and altered renal development in rat fetuses. Reprod Sci 22:156-64
Shi, Lijun; Liao, Jingwen; Liu, Bailin et al. (2015) Mechanisms and therapeutic potential of microRNAs in hypertension. Drug Discov Today 20:1188-204
Song, Minwoo A; Paradis, Alexandra N; Gay, Maresha S et al. (2015) Differential expression of microRNAs in ischemic heart disease. Drug Discov Today 20:223-35
Xiao, DaLiao; Huang, Xiaohui; Li, Yong et al. (2015) Antenatal Antioxidant Prevents Nicotine-Mediated Hypertensive Response in Rat Adult Offspring. Biol Reprod 93:66

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