Transcript Antenatal Maternal Stress: Epigenetic Mechanisms of

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