Epigenetic mechanisms in fetal origins of health and disease

Gestational exposure to the great Chinese famine: early life undernutrition impact on prostatic hyperplasia in adulthood

Introduction

Benign prostatic hyperplasia (BPH) is a frequent illness in aged men that impacts their quality of life; early childhood exposure to famines may have long-term effects on the chance of developing BPH. The aim of this study is to investigate the relationship between early-life famine exposure and benign prostatic hyperplasia (BPH) risk in Chinese men born during 1959-1961.

Methods

We used medical records from a large, comprehensive hospital to screen people born in China during the years of famine (1959-1961). Birthplaces were identified as indicators of famine exposure status. In the time window between 2017 and 2022, people born during the famine years who had prostatic ultrasonic examinations were selected, and their medical records were retrieved from the database. Univariate and multivariate logistic regression analyses investigated the relationship between famine exposure and BPH risk.

Results

A total of 3,009 subjects were included in this study. Patients with heavy famine exposure had older age, shorter height, lighter weight, lower cholesterol, lower uric acid (UA), lower aspartate aminotransferase (ALT), and a higher incidence of BPH than those with light famine exposure (all p < 0.05). Univariate logistic regression showed that BPH was positively related to famine exposure, age, height, weight, and body mass index (BMI) but negatively related to UA (all p < 0.05). Multivariate logistic regression showed that age and famine exposure were still independent risk factors (p < 0.05), while UA was an independent protective factor for BPH (p < 0.05). Heavy famine exposure increased the risk of BPH (adjusted OR = 1.214, 95% CI = 1.05-1.467, p = 0.045).

Conclusions and recommendation

Famine and malnutrition exposure during early life may be independent risk factors for BPH in Chinese adults. This relationship provides additional evidence to support the fetal origins of adult diseases and offers clues for the pathological mechanisms of BPH.

Vilazodone Alleviates Neurogenesis-Induced Anxiety in the Chronic Unpredictable Mild Stress Female Rat Model: Role of Wnt/β-Catenin Signaling

Defective β-catenin signaling is accompanied with compensatory neurogenesis process that may pave to anxiety. β-Catenin has a distinct role in alleviating anxiety in adolescence; however, it undergoes degradation by the degradation complex Axin and APC. Vilazodone (VZ) is a fast, effective antidepressant with SSRI activity and 5-HT1A partial agonism that amends somatic and/or psychic symptoms of anxiety. Yet, there is no data about anxiolytic effect of VZ on anxiety-related neurogenesis provoked by stress-reduced β-catenin signaling. Furthermore, females have specific susceptibility toward psychopathology. The aim of the present study is to uncover the molecular mechanism of VZ relative to Wnt/β-catenin signaling in female rats. Stress-induced anxiety was conducted by subjecting the rats to different stressful stimuli for 21 days. On the 15th day, stressed rats were treated with VZ(10 mg/kg, p.o.) alone or concomitant with the Wnt inhibitor: XAV939 (0.1 mg/kg, i.p.). Anxious rats showed low β-catenin level turned over by Axin-1 with unanticipated reduction of APC pursued with elevated protein levels of neurogenesis-stimulating proteins: c-Myc and pThr183-Erk likewise gene expressions of miR-17-5p and miR-18. Two weeks of VZ treatment showed anxiolytic effect figured by alleviation of hippocampal histological examination. VZ protected β-catenin signal via reduction in Axin-1 and elevation of APC conjugated with modulation of β-catenin downstream targets. The cytoplasmic β-catenin turnover by Axin-1 was restored by XAV939. Herein, VZ showed anti-anxiety effect, which may be in part through regaining the balance of the reduced β-catenin and its subsequent exaggerated response of p-Erk, c-Myc, Dicer-1, miR-17-5p, and miR-18.

The Effect of Maternal Diet and Physical Activity on the Epigenome of the Offspring

The aim of this review was to examine the current literature regarding the effect of maternal lifestyle interventions (i.e., diet and physical activity) on the epigenome of the offspring. PubMed, Scopus and Cochrane-CENTRAL were screened until 8 July 2023. Only randomized controlled trials (RCTs) where a lifestyle intervention was compared to no intervention (standard care) were included. Outcome variables included DNA methylation, miRNA expression, and histone modifications. A qualitative approach was used for the consideration of the studies' results. Seven studies and 1765 mother-child pairs were assessed. The most common types of intervention were dietary advice, physical activity, and following a specific diet (olive oil). The included studies correlated the lifestyle and physical activity intervention in pregnancy to genome-wide or gene-specific differential methylation and miRNA expression in the cord blood or the placenta. An intervention of diet and physical activity in pregnancy was found to be associated with slight changes in the epigenome (DNA methylation and miRNA expression) in fetal tissues. The regions involved were related to adiposity, metabolic processes, type 2 diabetes, birth weight, or growth. However, not all studies showed significant differences in DNA methylation. Further studies with similar parameters are needed to have robust and comparable results and determine the biological role of such modifications.

Comparative Analysis of the GH/IGF-1 Axis during the First Sixth Months in Children with Low Birth Weight

OBJECTIVE

To analyze the relation between alterations in the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis during the first 6 months of life and weight in children born in the lower-middle São Francisco region.

METHODS

This is an analytical cohort and exploratory. Thirty children, were formed two groups, one of low birth weight children (LBW, n = 15) and another of normal weight (NBW = 15) were initially identified in a hospital and reapproached at 3 and 6 months of age. Birth weight and alterations in GH/IGF-1 curves were measured at birth and the third and sixth months of life.

RESULTS

Weight gain during the 6 months of follow-up in newborns with a low birth weight was greater compared to newborns with a normal birth weight. All children who were born with a low birth weight had an altered GH/IGF-1 curve at birth (p = 0.002). Most newborns with a low birth weight maintained the alteration in the GH/IGF-1 curve at the third month of life (p = 0.027). Regarding the GH/IGF-1 curve at the sixth month, alteration persisted in greater proportion among children with a low birth weight.

CONCLUSIONS

Alterations in insulin resistance markers, demonstrated by increased GH without a proportional increase in IGF-1, were observed to be significant in children with a low birth weight with greater adiposity in this group which may increase the risk of metabolic diseases in later life.

Does Where You Live Predict What You Say? Associations between Neighborhood Factors, Child Sleep, and Language Development

Language ability is strongly related to important child developmental outcomes. Family-level socioeconomic status influences child language ability; it is unclear if, and through which mechanisms, neighborhood-level factors impact child language. The current study investigated the association between neighborhood factors (deprivation and disorder) assessed before birth and child language outcomes at age 5, with sleep duration as a potential underlying pathway. Secondary analysis was conducted on data collected between 2008 and 2018 on a subsample of 2444 participants from the All Our Families cohort study (Calgary, Canada) for whom neighborhood information from pregnancy could be geocoded. Neighborhood deprivation was determined using the Vancouver Area Neighborhood Deprivation Index (VANDIX), and disorder was assessed using crime reports. Mothers reported on their children’s sleep duration and language ability. Multilevel modeling indicated that greater neighborhood deprivation and disorder during pregnancy were predictive of lower scores on the Child Communication Checklist–2 (CCC–2) at 5 years. Path analyses revealed an indirect effect of neighborhood disorder on language through child sleep duration at 12 months. These results add to growing evidence that child development should be considered within the context of multiple systems. Sleep duration as an underlying link between environmental factors and child language ability warrants further study as a potential target for intervention.

Physical activity intervention improved the number and functionality of endothelial progenitor cells in low birth weight children

BACKGROUND AND AIMS

The purpose of this study was to investigate whether an intervention with physical activity (PA) would promote positive effects on the angiogenic factors, mobilization, and functionality of circulating endothelial progenitor cells (EPCs) in children with low birth weight (LBW).

METHODS AND RESULTS

Thirty-five children participated in a 10-week PA program (intensity: 75-85% of heart rate reserve, frequency: four times/week, and duration: 45 min). Before and after the PA program, we evaluated anthropometric parameters, blood pressure levels, biochemical profile, number of EPCs, number of EPC colony forming units, and plasma levels of vascular endothelial growth factor-A (VEGF-A), nitric oxide (NO), and matrix metalloproteinases (MMPs) 2 and 9. We found a significant main effect of the PA program on waist circumference (η_p² = 0.489), cardiorespiratory fitness (η_p² = 0.463), and MMP-9 (η_p² = 0.582). Birth weight or the PA program produced significant independent effects on systolic blood pressure (birth weight: η_p² = 0.431; PA program: η_p² = 0.615) and EPC colony forming units (birth weight: η_p² = 0.541; PA program: η_p² = 0.698) with no significant interactions. The combination of birth weight and the PA program produced a significant interaction effect on the number of circulating EPCs (η_p² = 0.123), NO (η_p² = 0.258), and VEGF-A (η_p² = 0.175). The variation in the number of EPCs from baseline to 10 weeks of the PA program correlated positively with the change in NO (P = 0.002) and VEGF-A (P = 0.004).

CONCLUSIONS

A 10-week PA program attenuates the adverse effect of LBW on the number and functionality of EPCs; this effect occurs through an improvement in circulating levels of NO and VEGF-A. CLINICAL TRIALS: https://www.clinicaltrials.gov. Unique Identifier: NCT02982967. Date: December/2016.

Socio-economic and racial prenatal diet quality disparities in a national US sample

OBJECTIVE

To examine differences in prenatal diet quality by socio-economic status (SES) and race/ethnicity.

DESIGN

A secondary, cross-sectional analysis. Race and SES were self-reported prenatally; SES was categorized into four groups: high-income, middle-income and low-income WIC (Special Supplemental Nutrition Program for Women, Infants, and Children) participant/non-participant. The Alternative Healthy Eating Index for Pregnancy (AHEI-P) measured diet quality, including four moderation and nine adequacy components (higher scores = healthier diet). Generalized linear models adjusted for covariates and post hoc testing with Tukey adjustment compared AHEI-P scores between groups, using a threshold of P < 0·05.

SETTING

Infant Feeding Practices Study II, conducted in a national US convenience cohort.

PARTICIPANTS

Women in their third trimester (n 1322) with dietary history.

RESULTS

Participants were of 28·9 (se 5·6) years on average and predominantly non-Hispanic White (84 %); approximately one-third participated in WIC and 17 % were high-income. The mean AHEI-P score was 61·7 (se 10·8) of 130 points. High-income women had higher total (62·4 (se 1·0)) and moderation component AHEI-P scores than middle-income (60·1 (se 0·8), P = 0·02), low-income WIC participants (58·3 (se 0·8), P < 0·0001) and non-participants (58·9 (se 0·9), P = 0·001). Non-Hispanic Black participants had lower total (57·8 (se 1·4)) and adequacy scores than Other races (i.e. neither non-Hispanic Black nor White, 62·1 (se 0·9), P = 0·02).

CONCLUSIONS

Disparities in prenatal diet quality were observed, with non-Hispanic Black women, low-/middle-income and WIC participants having lower diet quality. However, interventions are needed to improve prenatal diet quality broadly among US women.

Adverse maternal environment leads to cardiac fibrosis in adult male mice

BACKGROUND

Cardiac fibrosis is a cardinal feature of multiple types of cardiovascular disease, which lead to heart failure. Multiple studies connect adverse maternal environment (AME) with cardiac fibrosis. AME does not always result in fibrosis, though. An additional "insult", such as an adult Western diet (WD), is frequently necessary. The additive effects of AME and adult WD on cardiac fibrosis is not well-understood. AME can also alter DNA methylation. DNA methyltransferase (DNMT) and ten-eleven translocation (TET) are methylation modifying genes that regulate DNA methylation, but it is unknown if AME changes cardiac gene expression of DNMT and TET. We sought to use a model of AME and adult WD to investigate the development of cardiac fibrosis and cardiac mRNA expression of DNMT and TET genes.

METHODS

We exposed dams to WD or control diet (CD) 5 weeks before pregnancy and through lactation. We added environmental stressors during the last third of pregnancy to dams on WD to create AME. Dams on CD experienced no added stressors to create control maternal environment (CME). Male offspring were weaned at Postnatal Week 3 (W3) and placed on WD or CD to create four groups: CME-CD, CME-WD, AME-CD, and AME-WD.

RESULTS

AME-WD increased cardiac fibrosis in adulthood (p < .05), whereas AME-CD and CME-WD did not. TET1-3 and DNMT3a mRNA levels decreased in AME versus CME offspring (p < .01).

CONCLUSION

AME increases susceptibility to cardiac fibrosis in adult male mice. Early-life changes to TET expression may mediate susceptibility to fibrosis, but further testing is needed.

Illawarra Born cross-generational health study: feasibility of a multi-generational birth cohort study

Background

There is a strong interest in the concept of developmental origins of health and disease and their influence on various factors “from cradle to grave”. Despite the increasing appreciation of this lifelong legacy across the human life course, many gaps remain in the scientific understanding of mechanisms influencing these formative phases. Cross-generational susceptibility to health problems is emerging as a focus of research in the context of birth cohort studies.

The primary aim of the Illawarra Born study is to make scientific discoveries associated with improving health and wellbeing across the lifespan, with a particular focus on preventable chronic diseases, especially mental health. This birth cohort study will follow and collect data from three cohorts representing different stages across the lifespan: infants, adults (parents) and older adults (grandparents). The multi-generational, cross-sectional and longitudinal design of this birth cohort study supports a focus on the contributions of genetics, environment and lifestyle on health and wellbeing. The feasibility of conducting a multi-generational longitudinal birth cohort project was conducted through a small pilot study.

Methods/design

The purpose of this paper is to report on the feasibility and acceptability of the research protocol for a collaborative cross-generation health study in the community and test recruitment and outcome measures for the main study. This feasibility study included pregnant women who were intending to give birth in the Illawarra-Shoalhaven region in Eastern Australia. The area includes a large, regional referral hospital, with capacity to treat specialist and complex cases. Pregnant women were asked to participate in five data collection waves beginning at 22 weeks gestation and ending with a 6-month post-partum appointment. Recruitment was then extended, via the pregnant women, to also include fathers and maternal grandmothers.

Discussion

This feasibility study focused on the perinatal period and collected data across three multi-disciplinary domains including mental health, diet, exposures to toxins and the role of these in maternal and infant outcomes. Forty-one families participated in extensive data collection from 22 weeks gestation to 6-months post-partum. Factors impacting on viability and feasibility including recruitment solutions provide the basis for a large-scale study.

Epigenetics for the pediatric cardiologist

A genetic basis of congenital heart disease (CHD) has been known for decades. In addition to the sequence of the genome, the contribution of epigenetics to pediatric cardiology is increasingly recognized. Multiple epigenetic mechanisms, including DNA methylation, histone modification, and RNA-based regulation, are known mediators of cardiovascular disease, including both development and progression of CHD and its sequelae. Basic understanding of the concepts of epigenetics will be essential to all pediatric cardiologists in order to understand mechanisms of pathophysiology, pharmacotherapeutic concepts, and to understand the role of epigenetics in precision medicine.

Constitutional Epi/Genetic Conditions: Genetic, Epigenetic, and Environmental Factors

There are more than 4,000 phenotypes for which the molecular basis is at least partly known. Though defects in primary DNA structure constitute a major cause of these disorders, epigenetic disruption is emerging as an important alternative mechanism in the etiology of a broad range of congenital and developmental conditions. These include epigenetic defects caused by either localized (in cis) genetic alterations or more distant (in trans) genetic events but can also include environmental effects. Emerging evidence suggests interplay between genetic and environmental factors in the epigenetic etiology of several constitutional "epi/genetic" conditions. This review summarizes our broadening understanding of how epigenetics contributes to pediatric disease by exploring different classes of epigenomic disorders. It further challenges the simplistic dogma of "DNA encodes RNA encodes protein" to best understand the spectrum of factors that can influence genetic traits in a pediatric population.

In vitro fertilization (IVF) in mammals: epigenetic and developmental alterations. Scientific and bioethical implications for IVF in humans

The advent of in vitro fertilization (IVF) in animals and humans implies an extraordinary change in the environment where the beginning of a new organism takes place. In mammals fertilization occurs in the maternal oviduct, where there are unique conditions for guaranteeing the encounter of the gametes and the first stages of development of the embryo and thus its future. During this period a major epigenetic reprogramming takes place that is crucial for the normal fate of the embryo. This epigenetic reprogramming is very vulnerable to changes in environmental conditions such as the ones implied in IVF, including in vitro culture, nutrition, light, temperature, oxygen tension, embryo-maternal signaling, and the general absence of protection against foreign elements that could affect the stability of this process. The objective of this review is to update the impact of the various conditions inherent in the use of IVF on the epigenetic profile and outcomes of mammalian embryos, including superovulation, IVF technique, embryo culture and manipulation and absence of embryo-maternal signaling. It also covers the possible transgenerational inheritance of the epigenetic alterations associated with assisted reproductive technologies (ART), including its phenotypic consequences as is in the case of the large offspring syndrome (LOS). Finally, the important scientific and bioethical implications of the results found in animals are discussed in terms of the ART in humans.

Associating schizophrenia, long non-coding RNAs and neurostructural dynamics

Several lines of evidence indicate that schizophrenia has a strong genetic component. But the exact nature and functional role of this genetic component in the pathophysiology of this mental illness remains a mystery. Long non-coding RNAs (lncRNAs) are a recently discovered family of molecules that regulate gene transcription through a variety of means. Consequently, lncRNAs could help us bring together apparent unrelated findings in schizophrenia; namely, genomic deficiencies on one side and neuroimaging, as well as postmortem results on the other. In fact, the most consistent finding in schizophrenia is decreased brain size together with enlarged ventricles. This anomaly appears to originate from shorter and less ramified dendrites and axons. But a decrease in neuronal arborizations cannot explain the complex pathophysiology of this psychotic disorder; however, dynamic changes in neuronal structure present throughout life could. It is well recognized that the structure of developing neurons is extremely plastic. This structural plasticity was thought to stop with brain development. However, breakthrough discoveries have shown that neuronal structure retains some degree of plasticity throughout life. What the neuroscientific field is still trying to understand is how these dynamic changes are regulated and lncRNAs represent promising candidates to fill this knowledge gap. Here, we present evidence that associates specific lncRNAs with schizophrenia. We then discuss the potential role of lncRNAs in neurostructural dynamics. Finally, we explain how dynamic neurostructural modifications present throughout life could, in theory, reconcile apparent unrelated findings in schizophrenia.

Offspring DNA methylation of the aryl-hydrocarbon receptor repressor gene is associated with maternal BMI, gestational age, and birth weight

Prenatal smoke exposure, maternal obesity, aberrant fetal growth, and preterm birth are all risk factors for offspring metabolic syndrome. Cord blood aryl-hydrocarbon receptor repressor (AHRR) DNA methylation is responsive to maternal smoking during pregnancy. AHRR serves not only to inhibit aryl-hydrocarbon receptor (AHR) transcription, which is involved in mediating xenobiotic metabolism, but it is also involved in cell growth and differentiation. Other than maternal smoking, other predictors of offspring AHRR DNA methylation status remain unknown; we sought to identify them among newborns. We enrolled pregnant women in the PROGRESS birth cohort in Mexico City. Using pyrosequencing, we analyzed DNA methylation of 3 CpG sites within the AHRR gene promoter from the umbilical cord blood of 531 infants. We used generalized estimating equations to account for the correlation of DNA methylation between CpG sites. Multivariable models were used to adjust for maternal age, BMI, education, parity, smoke-exposure, infant sex, gestational age, and birth weight-for-gestational age. AHRR DNA methylation was positively associated with maternal BMI (P = 0.0009) and negatively associated with the length of gestation (P < 0.0001) and birth weight-for-gestational age (P < 0.0001). AHRR DNA methylation was 2.1% higher in offspring of obese vs. normal weight mothers and 3.1% higher in preterm vs. term infants, representing a third and a half standard deviation differences in methylation, respectively. In conclusion, offspring AHRR DNA methylation was associated with maternal obesity during pregnancy as well as infant gestational age and birth weight-for-gestational age. Further work to discover the health impacts of altered AHRR DNA methylation is warranted.

Epigenetic Regulation of Placenta-Specific 8 Contributes to Altered Function of Endothelial Colony-Forming Cells Exposed to Intrauterine Gestational Diabetes Mellitus

Intrauterine exposure to gestational diabetes mellitus (GDM) is linked to development of hypertension, obesity, and type 2 diabetes in children. Our previous studies determined that endothelial colony-forming cells (ECFCs) from neonates exposed to GDM exhibit impaired function. The current goals were to identify aberrantly expressed genes that contribute to impaired function of GDM-exposed ECFCs and to evaluate for evidence of altered epigenetic regulation of gene expression. Genome-wide mRNA expression analysis was conducted on ECFCs from control and GDM pregnancies. Candidate genes were validated by quantitative RT-PCR and Western blotting. Bisulfite sequencing evaluated DNA methylation of placenta-specific 8 (PLAC8). Proliferation and senescence assays of ECFCs transfected with siRNA to knockdown PLAC8 were performed to determine functional impact. Thirty-eight genes were differentially expressed between control and GDM-exposed ECFCs. PLAC8 was highly expressed in GDM-exposed ECFCs, and PLAC8 expression correlated with maternal hyperglycemia. Methylation status of 17 CpG sites in PLAC8 negatively correlated with mRNA expression. Knockdown of PLAC8 in GDM-exposed ECFCs improved proliferation and senescence defects. This study provides strong evidence in neonatal endothelial progenitor cells that GDM exposure in utero leads to altered gene expression and DNA methylation, suggesting the possibility of altered epigenetic regulation.

Heritable IUGR and adult metabolic syndrome are reversible and associated with alterations in the metabolome following dietary supplementation of 1-carbon intermediates

Metabolic syndrome (MetS), following intrauterine growth restriction (IUGR), is epigenetically heritable. Recently, we abrogated the F2 adult phenotype with essential nutrient supplementation (ENS) of intermediates along the 1-carbon pathway. With the use of the same grandparental uterine artery ligation model, we profiled the F2 serum metabolome at weaning [postnatal day (d)21; n = 76] and adulthood (d160; n = 12) to test if MetS is preceded by alterations in the metabolome. Indicative of developmentally programmed MetS, adult F2, formerly IUGR rats, were obese (621 vs. 461 g; P < 0.0001), dyslipidemic (133 vs. 67 mg/dl; P < 0.001), and glucose intolerant (26 vs. 15 mg/kg/min; P < 0.01). Unbiased gas chromatography-mass spectrometry (GC-MS) profiling revealed 34 peaks corresponding to 12 nonredundant metabolites and 9 unknowns to be changing at weaning [false discovery rate (FDR) < 0.05]. Markers of later-in-life MetS included citric acid, glucosamine, myoinositol, and proline (P < 0.03). Hierarchical clustering revealed grouping by IUGR lineage and supplementation at d21 and d160. Weanlings grouped distinctly for ENS and IUGR by partial least-squares discriminate analysis (PLS-DA; P < 0.01), whereas paternal and maternal IUGR (IUGR(pat)/IUGR(mat), respectively) control-fed rats, destined for MetS, had a distinct metabolome at weaning (randomForest analysis; class error < 0.1) and adulthood (PLS-DA; P < 0.05). In sum, we have found that alterations in the metabolome accompany heritable IUGR, precede adult-onset MetS, and are partially amenable to dietary intervention.

Global DNA methylation was changed by a maternal high-lipid, high-energy diet during gestation and lactation in male adult mice liver

An epigenetic mechanism has been suggested to explain the effects of the maternal diet on the development of disease in offspring. The present study aimed to observe the effects of a maternal high-lipid, high-energy (HLE) diet on the DNA methylation pattern of male offspring in mice. Female C57BL/6J mice were fed an HLE diet during gestation and lactation. The genomic DNA methylations at promoter sites of genes in the liver, mRNA and protein levels of selected genes related to lipid and glucose metabolism were measured by microarray, real-time PCR and Western blot. The results indicated that the percentage of methylated DNA in offspring from dams that were fed an HLE diet was significantly higher than that from dams that were fed a chow diet, and most of these genes were hypermethylated in promoter regions. The nuclear protein content and mRNA levels of hypermethylated genes, such as PPARγ and liver X receptor α (LXRα), were decreased significantly in offspring in the HLE group. The results suggested that the DNA methylation profile in adult offspring livers was changed by the maternal HLE diet during gestation and lactation.

Programmed hyperphagia secondary to increased hypothalamic SIRT1

Small for gestational age (SGA) offspring exhibit reduced hypothalamic neural satiety pathways leading to programmed hyperphagia and adult obesity. Appetite regulatory site, the hypothalamic arcuate nucleus (ARC) contains appetite (NPY/AgRP) and satiety (POMC) neurons. Using in vitro culture of hypothalamic neuroprogenitor cells (NPC) which form the ARC, we demonstrated that SGA offspring exhibit reduced NPC proliferation and neuronal differentiation. bHLH protein Hes1 promotes NPC self-renewal and inhibits differentiation by repressing neuronal differentiation genes (Mash1, neurogenin3). We hypothesized that Hes1/Mash1 and ultimately ARC neuronal differentiation and expression of NPY/POMC neurons are influenced by SIRT1 which is a nutrient sensor and a histone deacetylase. Control dams received ad libitum food, whereas study dams were 50% food-restricted from pregnancy day 10 to 21 (SGA). In vivo studies showed that SGA newborns and adult offspring had increased protein expression of hypothalamic/ARC SIRT1 and AgRP with decreased POMC. Additionally, SGA newborns had decreased expression of hypothalamic neurogenic factors with reduced in vivo NPC proliferation. In vitro culture of hypothalamic NPCs showed similar changes with elevated SIRT1 binding to Hes1 in SGA newborn. Silencing SIRT1 increased NPC proliferation and Hes1 and Tuj1expression in both Control and SGA NPCs. Although SGA NPC proliferation remained below that of Controls, it was higher than Control NPCs in the absence of SIRT1 siRNA. The direct impact of SIRT1 on NPC proliferation and differentiation were further confirmed with pharmacologic SIRT1 inhibitor and activator. Thus, in SGA newborns elevated SIRT1 induces premature differentiation of NPCs, reducing the NPC pool and cell proliferation.

Xenotransplantation of human fetal adipose tissue: a model of in vivo adipose tissue expansion and adipogenesis

Obesity during childhood and beyond may have its origins during fetal or early postnatal life. At present, there are no suitable in vivo experimental models to study factors that modulate or perturb human fetal white adipose tissue (WAT) expansion, remodeling, development, adipogenesis, angiogenesis, or epigenetics. We have developed such a model. It involves the xenotransplantation of midgestation human WAT into the renal subcapsular space of immunocompromised SCID-beige mice. After an initial latency period of approximately 2 weeks, the tissue begins expanding. The xenografts are healthy and show robust expansion and angiogenesis for at least 2 months following transplantation. Data and cell size and gene expression are consistent with active angiogenesis. The xenografts maintain the expression of genes associated with differentiated adipocyte function. In contrast to the fetal tissue, adult human WAT does not engraft. The long-term viability and phenotypic maintenance of fetal adipose tissue following xenotransplantation may be a function of its autonomous high rates of adipogenesis and angiogenesis. Through the manipulation of the host mice, this model system offers the opportunity to study the mechanisms by which nutrients and other environmental factors affect human adipose tissue development and biology.