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Antenatal Maternal Stress: Epigenetic Mechanisms of Developmental Programming of Diseases Ravi Goyal, MD, PhD Assistant Professor Center for Perinatal Biology School of Medicine Loma Linda University Developmental Origin Hypothesis The “Developmental Origin of Adult Health and Disease” proposes that under-nutrition in-utero permanently changes body functions and metabolism leading to an increased risk of diseases in adult life • Barker’s Hypothesis • Fetal programming of adult health and disease Barker et al, 1991 The Dutch Hunger Winter • World War II • The Dutch government (exile in London) called a general railway strike in the northern and western Netherlands • Germans retaliated • All food transport to western and northern Netherlands was interdicted The Hunger Winter • Winter of 1944/1945 was unusually harsh • Canals rapidly froze over and became impassable for barges • Lasted 6 months, from November 1944- May 5, 1945, when Holland was liberated from the German occupation Adult rations - 400-800 calories a day (less than a quarter of the recommended adult caloric intake) The Dutch Hunger Winter: Birth Cohorts Ravelli, G.-P., et al. N Engl J Med 1976; 295:349-353 Barker et al., Fetal origins of coronary heart disease. BMJ, 311: 1995 Epidemiological Studies • Adult cohorts show that low infant weight is strongly associated with an increased disease risk – Barker DJP Lancet 1989 – Eriksson JG Diabetologia 2003;46:190 – Bhargava S New Eng J Med 2004;350:865 The effects of the famine • Increased incidence of – Hypertension – Type -2 DM – Cardiovascular mortality – Schizophrenia Baby born during the hunger winter – Obesity First 2 trimesters - 80% higher prevalence of overweight (p<0.0005) The Thrifty Phenotype As a result of poor nutritional conditions, a pregnant female can modify the development of her unborn child such that it will be prepared for survival in an environment in which resources are likely to be short, resulting in a thrifty phenotype (Hales & Barker, 1992) Our studies • Mice (FVB/NJ) • Control, 50% protein diet and 33% protein diet (isocaloric) • Mice consumed approximately equal amount of food Research Questions • How does this developmental programming occurs? • What are the molecular mechanisms? • What are the genetic and epigenetic changes in specific signal transduction pathways? Maternal Protein Deprivation Baby born during the hunger winter IUGR Birth Weight was reduced but not the litter Isocaloric diet with reduced size protein intake can lead to IUGR What if a thrifty phenotype child is given excess nutrition? Rapid catch-up growth – Obesity – Hypertension – Diabetes Maternal Protein Deprivation IUGR Rapid Catch-up Growth Rapid catch-up growth Rapid catch-up growth Maternal Protein Deprivation IUGR Rapid Catch-up Growth Obesity Adipose Volume in Adult Offspring Maternal Protein Deprivation IUGR Rapid Catch-up Growth Hypertension Mean Arterial Blood Pressure in Females Mean Arterial Blood Pressure in Males Maternal Protein Deprivation Hypertension IUGR Blood Sugar Rapid Catch-up Growth Obesity Prenatal protein malnutrition and blood glucose levels in adult life Insulin levels were unchanged Maternal Protein Deprivation Altered gene expression Renin – Angiotensin System Hypertension Renin-Angiotensin System (Systemic & Local) Angiotensiongen (AGT) Renin (REN) Angiotensin 1 Angiotensin 1 Converting Enzyme (ACE1) Angiotensin 2 Angiotensin 2 Converting Enzyme (ACE2) Ang 1-7 Angiotensin 2 Type 1 Receptor (AT1) Angiotensin 2 Type 2 Receptor (AT2) Angiotensin 1 Converting Enzyme (Brain) Protein Deprivation Epigenetic Changes Maternal Hypoxia Caloric Excess Maternal Protein Deprivation Epigenetic Changes Altered gene expression Hypertension Epigenetics Heritable changes in phenotype or gene expression caused by mechanisms other than changes in DNA sequence per se Epigenetic Changes Transcriptional Regulation Translational Regulation DNA methylation Histone Modifications miRNA, lnRNA-mediated regulation DNA Methylation – Transcriptional Modification CH3 CH3 CH3 CH3 CH3 CH3 CH3 3’ CH3 CH3 CH3 5’ Transcription Hindered – Less mRNA RNA Polymerase Methylated CpG Islands in Promoter Region Hypomethylated CpG Islands 3’ RNA Polymerase 5’ Higher amount of mRNA mRNA Angiotensin 1 Converting Enzyme (Fetal Brain) is ACE promoter hypomethylated? Fetal Brain ACE1 – DNA Methylation Hypomethylated CpG Islands in ACE1 Upregulates Gene Expression Normal Diet Maternal Low Protein Diet Question to Consider • The programming occurs during fetal life and mRNA are increased during fetal life, then why does blood pressure remains normal until adulthood? Angiotensin 1 Converting Enzyme (Brain) Control Diet MLPD Although, the mRNA levels of ACE1 are increased, the protein expression remains low .. microRNA - Post-Transcriptional regulation UTR 3’ microRNA 5’ mRNA Translation Increased microRNA causes decreased protein expression ACE1 Protein ACE1 Protein ACE1 Protein ACE1 Protein ACE1 Protein ACE1 Protein Micro RNAs • identified miRNA putatively regulating ACE translation • mmu-mir-27a and mmu-mir-27b ACE1 microRNAs (Brain) Increased microRNA targeted for ACE1 leads to decreased protein expression MLPD Hypo-methylation of ACE promoter Increased ACE mRNA Up-regulation of miRNA Reduced/normal ACE protein expression Programming of Hypertension Hypertension Current Project scAAV viral vector-mediated production of miRNA 27a in hypertensive mice lungs 27a CBAP scAAV.CBAP.27a.eGFP CBAP scAAV.CBAP.27a Conclusion Maternal Stress during Pregnancy Epigenetic Changes Changes in Gene Products Physiological/Pathological Changes Acknowledgements – Lawrence D. Longo, MD – Ciprian Georghe, MD, PhD – Dipali Goyal, BS – Andre Obenaus, PhD – Nina Chu, BS – Andrew Gallfy, BS – E Eun Jang, MD – Toni-An Wright, B.S. Thank You