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Key points The prevalence of obesity and non-alcoholic fatty liver disease in children is dramatically increasing at the same time as consumption of foods with a high sugar content. Intake of high fructose corn syrup (HFCS) is a possible etiology as it is thought to be more lipogenic than glucose. In a mouse model, HFCS intake during adolescence increased fat mass and hepatic lipid levels in male and female mice. However, only males showed impaired glucose tolerance. Multiple metabolites including lipids, bile acids, carbohydrates, and amino acids were altered in liver in a sex-specific manner at 6 weeks of age. Some of these changes were also present in adulthood even though HFCS exposure ended at 6 weeks. HFCS significantly altered the gut microbiome which was associated with changes in key microbial metabolites. These results suggest that HFCS intake during adolescence has profound metabolic changes that are linked to changes in the microbiome and these changes are sex-specific. Abstract The rapid increase in obesity, diabetes and fatty liver disease in children over the past 20 years has been linked to increased high fructose corn syrup (HFCS) consumption making it essential to determine the short and long-term effects of HFCS during this vulnerable developmental window. We hypothesized that HFCS exposure during adolescence significantly impairs hepatic metabolic signaling pathways and alters gut microbial composition contributing to changes in energy metabolism with sex-specific effects. C57bl/6J mice with free access to HFCS during adolescence (3-6 weeks of age) underwent glucose tolerance and body composition testing and hepatic metabolomics, gene expression and triglyceride content analysis at 6 and 30 weeks of age (n = 6-8 per sex). At 6 weeks HFCS-exposed mice had significant increases in fat mass, glucose intolerance, hepatic triglycerides (females) and de novo lipogenesis gene expression (ACC, DGAT, FAS, ChREBP, SCD, SREBP, CPT and PPARα) with sex-specific effects. At 30 weeks HFCS-exposed mice also had abnormalities in glucose tolerance (males) and fat mass (females). HFCS exposure enriched carbohydrate, amino acid, long chain fatty acid and secondary bile acid metabolism at 6 weeks with changes in secondary bile metabolism at 6 and 30 weeks. Microbiome studies performed immediately before and after HFCS exposure identified profound shifts of microbial species in male mice only. In summary, a short-term HFCS exposure during adolescence induces fatty liver, alters important metabolic pathways, some of which continue to be altered in adulthood, and changes the microbiome in a sex-specific manner. This article is protected by copyright. All rights reserved.

Context Gestational diabetes (GDM) has profound effects on the intrauterine metabolic milieu and is linked to obesity and diabetes in offspring, but the mechanisms driving these effects remain largely unknown. Alterations in DNA methylation and gene expression in amniocytes exposed to GDM in utero represent a potential mechanism leading to metabolic dysfunction later in life. Objective To profile changes in genome-wide DNA methylation and expression in human amniocytes exposed to GDM. Design A nested case-control study (n = 14 pairs) was performed in amniocytes matched for offspring sex, maternal race/ethnicity, maternal age, gestational age at amniocentesis, and gestational age at birth. Sex-specific genome-wide DNA methylation analysis and RNA-sequencing were completed and differentially methylated regions (DMRs) and gene expression changes were identified. Ingenuity pathway analysis identified biologically relevant pathways enriched after GDM exposure. In silico high-throughput chromosome conformation capture (Hi-C) analysis identified potential chromatin interactions with DMRs. Results Expression of interferon-stimulated genes was increased in GDM amniocytes, accounting for 6 of the top 10 altered genes (q < 0.05). Enriched biological pathways in GDM amniocytes included pathways involving inflammation, the interferon response, fatty liver disease, monogenic diabetes, and atherosclerosis. Forty-two DMRs were identified in male GDM-exposed amniocytes and 20 in female amniocyte analysis (q < 0.05). Hi-C analysis identified interactions between DMRs and 11 genes with significant expression changes in male amniocytes and 9 in female amniocytes (P < .05). Conclusion In a unique repository of human amniocytes exposed to GDM in utero, transcriptome analysis identified enrichment of inflammation and interferon-related pathways and novel DMRs with potential distal regulatory functions.

Objective: Mutations in hepatocyte nuclear factor 1B (HNF1B), are often identified based on a history of renal disease and diabetes mellitus, but other endocrine manifestations including dyslipidemia and hyperparathyroidism have not been well-defined in the literature. Given HNF1B-MODY is rare, there have been few case series defining the disease spectrum. This study analyzes the clinical characteristics of HNF1B-related endocrine disorders in 9 pediatric patients identified at a single pediatric tertiary care center. Methods: Data was collected through the Atypical Diabetes Registry and Biorepository at the Children’s Hospital of Philadelphia. Results: Of the 9 pediatric patients with HNF1B mutations or deletions, 7/9 (78%) have diabetes mellitus, 8/9 (89%) have renal disease, 8/9 (89%) have dyslipidemia, and 5/9 (55%) have hyperparathyroidism. Over half (55%) initially presented with diabetes mellitus, while the remaining 45% were diagnosed either based on family history or a genetic workup secondary to renal disease. No patients presented with diabetic ketoacidosis and only two presented with ketosis. Of the 4/9 with previously identified HNF1B-mutations, two have subsequently developed diabetes mellitus. Lipid profiles demonstrated: 7/9 with total cholesterol >170 mg/dL, 8/9 with triglycerides >100 mg/dL, 3/9 with LDL > 110 mg/dL and 3/9 with HDL < 40 mg/dL. In regards to calcium homeostasis, 55% have an elevated PTH (>65 pg/mL) with high-normal calcium levels. Autism spectrum disorder was diagnosed in 3/9 patients (2 with 17q12 deletion and 1 with HNF1B mutation). Conclusion: This study represents one of the largest series of pediatric patients with HNF1B-MODY at a single center. The majority of patients have had progressively declining beta-cell function resulting in diabetes mellitus. Nearly all had elevated lipids with hypertriglyceridemia predominating. Over half of the patients had elevated PTH levels preceding the decline in renal function concerning for primary hyperparathyroidism. Disclosure M. E. Craven: None. V. Bamba: None. A. C. Calabria: None. S. E. Pinney: None.

Although type 1 diabetes mellitus and, to a lesser extent, type 2 diabetes mellitus, are the prevailing forms of diabetes in youth, atypical forms of diabetes are not uncommon and may require etiology-specific therapies. By some estimates, up to 6.5% of children with diabetes have monogenic forms. Mitochondrial diabetes and cystic fibrosis related diabetes are less common but often noted in the underlying disease. Atypical diabetes should be considered in patients with a known disorder associated with diabetes, aged less than 25 years with nonautoimmune diabetes and without typical characteristics of type 2 diabetes mellitus, and/or with comorbidities associated with atypical diabetes.

Background: Friedreich’s Ataxia (FA) is a neuromuscular disorder caused by either GAA triplet repeat expansions of both alleles of the gene frataxin, or less commonly, by a point mutation in one allele and triplet expansion on the other. FA is associated with an increased incidence of diabetes (DM), but risk factors and management are not well described. Objective: To report the prevalence of, identify risk factors for, and describe management of DM in FA using the large (N=1,020) multi-site, longitudinal, observational FA Outcomes Measures Study (FACOMS). Methods: FACOMS was queried for self-reported DM status and the modified FA Rating Scale (mFARS), which rates severity. For the subset at the Children’s Hospital of Philadelphia (CHOP), past medications were noted via EMR. Point mutation status and mFARS were compared in DM vs. non DM with chi-square and Wilcoxon signed rank tests, respectively. Independent risk factors for DM were tested by logistic regression including mFARS, age, point mutation, and age of FA diagnosis (dx). Results: Median age of FA dx was 14y (IQR 10-21), 5.7% had a point mutation, and 8.8% had DM. In those with DM, median age at DM dx was 27y (IQR 17-41) and mean HbA1c since dx was 7% (SD 1). Point mutations were more common in DM vs. non DM (13.9% vs. 4.9%; p Conclusions: DM in FA was associated with more severe disease, older age, and a point mutation. Many require insulin. Future studies will evaluate the pathophysiology of FA-related DM to inform screening practices and management decisions. Disclosure J. Tamaroff: None. A. DeDio: None. K.L. Wade: None. C. Rummey: None. S.E. Pinney: None. D. Lynch: None. A. Kelly: None. S. McCormack: Advisory Panel; Self; Reata Pharmaceuticals, Rhythm Pharmaceuticals. Other Relationship; Self; Levo Pharmaceuticals. Funding National Institutes of Health (T32DK063688-16); Uplifting Athletes; McCormack Children’s Hospital of Pittsburgh Metabolism, Nutrition, and Development Research Affinity Group; McCormack Friedreich’s Ataxia Research Alliance

Background: Perfluorooctanoic acid (PFOA), is a persistent fluorinated compound with oil and water repelling properties found in cookware, food packaging and municipal water systems. Adult animals exposed to PFOA develop hepatomegaly, fatty liver, peroxisome proliferation, and immunotoxicity. Rodents exposed to PFCs in utero have altered hepatic lipid metabolism, increased hepatic de novo lipogenesis and susceptibility to non-alcoholic fatty liver disease (NAFLD), but underlying molecular mechanisms remain unknown. With increasing rates of obesity, diabetes, and NAFLD it is critical to examine the mechanisms by which in utero exposure to PFOA contributes to the development of metabolic syndrome in offspring. Objective: To determine mechanism by which PFOA alters gene expression in undifferentiated hepatic progenitor cells. Design/methods: HepaRG cells, a human derived hepatocyte progenitor cell line, was treated with 0.5uM PFOA or vehicle for 48 hours followed by differentiation into hepatocytes. Total RNA was extracted using the RNeasy (Qiagen) [total RNA A260/280>2 and RNA integrity number >7 (Agilent Bioanalyzer)] to generate libraries with the Illumina TruSeq stranded total RNA kit. RNA-Seq was performed using 85 bp single-end read sequencing to generate >20 million reads per sample. RNAseq data was aligned to hg38 using STAR v2.6.1a and then quantified with featureCounts v1.6.2. DESeq2 identified differentially expressed genes via FDR (false discovery rate) after Bonferroni correction. Differentially expressed gene lists were used for Ingenuity Pathway Analysis (IPA) to identify pathways of biological significance. Results: PFOA treatment resulted in increased expression of transcription factors EGR1 (early growth response protein 1), NR4A1 (nuclear receptor Nur77), EGR2 (early growth response protein 2), KLF10 (Krueppel-like factor 10) and FOSL1 (Fos-related antigen 1), key genes linked to impaired hepatic insulin signaling, hepatic lipid metabolism, steatosis and fibrosis (fold change > 1.5; q

Although the factors responsible for the recent increase in the prevalence of diabetes worldwide are not entirely known, the morbidity associated with this disease results in substantial health and economic burden on society. Epigenetic modifications, including DNA methylation have been identified as one mechanism by which the environment interacts with the genome and there is evidence that alterations in DNA methylation may contribute to the increased prevalence of both type 1 and type 2 diabetes. This review provides a summary of DNA methylation and its role in gene regulation, and includes descriptions of various techniques to measure site-specific and genome-wide DNA methylation changes. In addition, we review current literature highlighting the complex relationship between DNA methylation, gene expression, and the development of diabetes and related complications. In studies where both DNA methylation and gene expression changes were reported, DNA methylation status had a strong inverse correlation with gene expression, suggesting that this interaction may be a potential future therapeutic target. We highlight the emerging use of genome-wide DNA methylation profiles as a biomarker to predict patients at risk of developing diabetes or specific complications of diabetes. The development of a predictive model that incorporates both genetic sequencing and DNA methylation data may be an effective diagnostic approach for all types of diabetes and could lead to additional innovative therapies.

Background: Gestational diabetes (GDM) has profound effects on the intrauterine metabolic milieu, induces marked abnormalities in fetal glucose and insulin secretion and is linked to obesity and diabetes in the offspring, but the mechanisms remain largely unknown. Objective: To measure changes in gene expression and genome wide DNA methylation in human amniocytes, a fetal stem cell, exposed to GDM in utero. Methods: EdgeR identified differentially expressed genes from RNASeq via fold change, p-values, and q-values calculated after Bonferoni correction (n=8; 4 per sex). RNA-Seq results were confirmed via QPCR. Ingenuity Pathway Analysis (IPA) identified enriched biological pathways. Differentially methylated regions (DMRs) were determined from Enhanced Reduced Representation Bisulfite Sequencing (ERRBS) (n=16; 8 per sex) by identifying sequential CpGs with significant changes in DNA methylation >5%, and with p Results: We identified 20 differentially expressed genes (q Conclusion: Exposure to GDM in utero leads changes in amniocyte gene expression and DNA methylation with enrichment in interferon inducible pathways. Disclosure S.E. Pinney: None. A. Joshi: None. V. Yin: None. S. Min: None. D.E. Condon: None. Z. Wang: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases (K08DK090302); National Institute of Environmental Health Sciences (P30ES013508); National Institutes of Health (UL1TR001878)

Context Prenatal exposure to bisphenol A (BPA) is linked to obesity and diabetes but the molecular mechanisms driving these phenomena are not known. Alterations in deoxyribonucleic acid (DNA) methylation in amniocytes exposed to BPA in utero represent a potential mechanism leading to metabolic dysfunction later in life. Objective To profile changes in genome-wide DNA methylation and expression in second trimester human amniocytes exposed to BPA in utero. Design A nested case-control study was performed in amniocytes matched for offspring sex, maternal race/ethnicity, maternal age, gestational age at amniocentesis, and gestational age at birth. Cases had amniotic fluid BPA measuring 0.251 to 23.74 ng/mL. Sex-specific genome-wide DNA methylation analysis and RNA-sequencing (RNA-seq) were performed to determine differentially methylated regions (DMRs) and gene expression changes associated with BPA exposure. Ingenuity pathway analysis was performed to identify biologically relevant pathways enriched after BPA exposure. In silico Hi-C analysis identified potential chromatin interactions with DMRs. Results There were 101 genes with altered expression in male amniocytes exposed to BPA (q < 0.05) in utero, with enrichment of pathways critical to hepatic dysfunction, collagen signaling and adipogenesis. Thirty-six DMRs were identified in male BPA-exposed amniocytes and 14 in female amniocyte analysis (q < 0.05). Hi-C analysis identified interactions between DMRs and 24 genes with expression changes in male amniocytes and 12 in female amniocytes (P < 0.05). Conclusion In a unique repository of human amniocytes exposed to BPA in utero, sex-specific analyses identified gene expression changes in pathways associated with metabolic disease and novel DMRs with potential distal regulatory functions.

BACKGROUND: Perfluorooctanoate (PFOA) has been used extensively in the manufacture of both commercial and household products. PFOA serum concentrations have been associated with adverse health effects, including lower body mass in children and infants. OBJECTIVE: To determine if there is an association between PFOA and body mass, insulin and lipid profile in exposed young girls. METHODS: We conducted a cross-sectional study of PFAS environmental biomarkers and insulin resistance in 6 to 8 year-old girls from Greater Cincinnati (n=353). In 2004–2006, blood samples were obtained to measure polyfluoroalkyl substances (PFAS), fasting insulin, glucose and lipids. Clinical exams included anthropometric measurements and pubertal maturation staging. Linear regression and mediation analyses, specifically structural equation modeling (SEM), were used to determine the strength and direction of the relationships between PFAS, pubertal maturation status, body mass index (BMI), cholesterol and insulin resistance. RESULTS: The median PFOA (7.7ng/ml) was twice the National Health and Nutrition Examination Survey (2005–2006). Only PFOA, a PFAS sub-species, showed statistically significant relationships with the outcomes. In regression models, PFOA was associated with decreased BMI and waist-to-height ratio (p=0.0008; p=0.0343), HDL-cholesterol (p=0.0046) and had a borderline inverse association with the HOMA Index of insulin resistance (p=0.0864). In SEM, PFOA retained an inverse relationship with BMI (p

Background/Objective Pregnancies complicated by gestational diabetes (GDM) or maternal obesity have been linked to the development of diabetes, obesity and fatty liver disease later in life with sex-specific manifestations. Alterations in miRNA expression in offspring exposed to GDM and maternal obesity and effects on hepatic development are unknown. Here we describe how exposure to maternal obesity in utero leads to sex-specific changes in miRNA and target gene expression in human fetal liver. Methods Candidate miRNA expression was measured in 2nd trimester amniotic fluid (AF) from women with GDM. Targets of differentially expressed miRNAs were determined and pathway enrichment of target genes was performed. MiRNA and target gene expression were measured in a separate cohort of 2nd trimester primary human fetal hepatocytes (PHFH) exposed to maternal obesity via QPCR and western blot. All studies were IRB approved. Results GDM exposed AF had significant increases in miRNAs 199a-3p, 503-5p, and 1268a (fold change (FC) ≥1.5, p

Maternal diabetes and obesity induce marked abnormalities in glucose homeostasis and insulin secretion in the fetus, and are linked to obesity, diabetes, and metabolic disease in the offspring, with specific metabolic characterization based on offspring sex. Gestational diabetes (GDM) has profound effects on the intrauterine milieu, which may reflect and/or modulate the function of the maternal&ndash, fetal unit. In order to characterize metabolic factors that affect offspring development, we profiled the metabolome of second trimester amniotic fluid (AF) from women who were subsequently diagnosed with gestational diabetes (GDM) using a targeted metabolomics approach, profiling 459 known biochemicals through gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) assays. Using a nested case-control study design, we identified 69 total biochemicals altered by GDM exposure, while sex-specific analysis identified 44 and 58 metabolites in male and female offspring, respectively. The most significant changes were in glucose, amino acid, glutathione, fatty acid, sphingolipid, and bile acid metabolism with specific changes identified based on the offspring sex. Targeted isotope dilution LC/MS confirmatory assays measured significant changes in docosahexaenoic acid and arachidonic acid. We conclude that the sex-specific alterations in GDM maternal&ndash, fetal metabolism may begin to explain the sex-specific metabolic outcomes seen in offspring exposed to GDM in utero.

Background: Pregnancies complicated by gestational diabetes (GDM) or maternal obesity (MOB) induce abnormal fetal development that can lead to diabetes and obesity later in life with sex specific manifestations. Alterations in miRNA expression in GDM and MOB exposed offspring and effects on development have not been fully described. Hypothesis: Exposure to an aberrant intrauterine milieu complicated by GDM and MOB leads to changes in miRNA and target gene expression in human fetal liver. Methods: Candidate miRNA expression was measured in second trimester AF from women diagnosed with GDM via multiplex miRNA assay (Firefly Bioworks, Abcam). Gene targets of differentially expressed miRNAs were determined from TargetScan and pathway enrichment determined via Ingenuity Pathway Analysis (IPA). MiRNA and target gene expression (mRNA and protein) were measured in a separate cohort of 2nd trimester primary human fetal hepatocytes (PHFH) exposed to MOB via QPCR and western blot. All studies were approved by UPENN and TEMPLE University IRBs. Results: GDM exposed AF had significant increases in miRNAs 199a-3p, 503-5p, and 1268a (p Conclusion: Our data suggest sex specific changes in miRNA and target gene expression in PHFH may be one mechanism responsible for sex specific metabolic changes in offspring exposed to GDM and obesity in utero. Disclosure A. Joshi: None. L. Goetzl: None. S.E. Pinney: None.

Intrauterine growth retardation has been linked to the development of type 2 diabetes later in life and the mechanisms underlying this phenomena are unknown. Epidemiological studies in humans show a distinct link with the exposure to an intrauterine insult that results in low birth weight and the development of type 2 diabetes in adulthood. Intrauterine growth retardation can be induced in rodent models by exposing the pregnant rat to a low protein diet, total calorie restriction, high dose glucocorticoids or inducing uteroplacental insufficiency, all which result in abnormalities in glucose homeostasis in the offspring later in life. Animal models of intrauterine growth retardation allow for a better characterization of changes in glucose homeostasis and corresponding changes in gene expression that can provide insight in the mechanisms by which intrauterine growth retardation leads to type 2 diabetes.

The link between an adverse intrauterine environment and the development of diabetes and obesity later in life has been observed in pregnancies complicated by poor intrauterine growth, maternal diabetes, and maternal obesity, but the molecular mechanisms underlying this phenomenon have not been defined clearly. In this chapter, we highlight what is currently known about the molecular mechanisms contributing to the development of diabetes and obesity in offspring exposed in utero to intrauterine growth restriction, gestational diabetes, and maternal obesity. This chapter describes the model systems that have been developed to study the effects of a disturbed intrauterine metabolic milieu on the offspring and translational studies on human subjects focusing on epigenetic modifications that alter gene expression.

The link between an adverse intrauterine environment and the development of disease later in life has been observed in offspring of pregnancies complicated by obesity and diabetes, but the molecular mechanisms underlying this phenomenon are unknown. In this review, we highlight recent publications exploring the role of gestational diabetes mellitus in the programming of disease in the offspring. We also review recent publications aiming to identify mechanisms responsible for the "programming effect" that results from exposure to diabetes in utero. Finally, we highlight research on the role of epigenetic regulation of gene expression in an animal model of uteroplacental insufficiency where the offspring develop diabetes as a model by which an exposure to the mother can alter epigenetic modifications that affect expression of key genes and ultimately lead to the development of diabetes in the offspring.

Congenital hyperinsulinism is a condition of dysregulated insulin secretion often caused by inactivating mutations of the ATP-sensitive K+ (KATP) channel in the pancreatic beta cell. Though most disease-causing mutations of the 2 genes encoding KATP subunits, ABCC8 (SUR1) and KCNJ11 (Kir6.2), are recessively inherited, some cases of dominantly inherited inactivating mutations have been reported. To better understand the differences between dominantly and recessively inherited inactivating KATP mutations, we have identified and characterized 16 families with 14 different dominantly inherited KATP mutations, including a total of 33 affected individuals. The 16 probands presented with hypoglycemia at ages from birth to 3.3 years, and 15 of 16 were well controlled on diazoxide, a KATP channel agonist. Of 29 adults with mutations, 14 were asymptomatic. In contrast to a previous report of increased diabetes risk in dominant KATP hyperinsulinism, only 4 of 29 adults had diabetes. Unlike recessive mutations, dominantly inherited KATP mutant subunits trafficked normally to the plasma membrane when expressed in COSm6 cells. Dominant mutations also resulted in different channel-gating defects, as dominant ABCC8 mutations diminished channel responses to magnesium adenosine diphosphate or diazoxide, while dominant KCNJ11 mutations impaired channel opening, even in the absence of nucleotides. These data highlight distinctive features of dominant KATP hyperinsulinism relative to the more common and more severe recessive form, including retention of normal subunit trafficking, impaired channel activity, and a milder hypoglycemia phenotype that may escape detection in infancy and is often responsive to diazoxide medical therapy, without the need for surgical pancreatectomy.

Objective:The aim was to describe the clinical presentation and to characterize the genetic mutation present in a child with congenital malabsorptive diarrhea and neonatal diabetes.Research Design and Methods:Clinical data were obtained from chart review. Histopathological characterization of intestinal samples and neurogenin-3 (NEUROG3) sequencing were performed. Expression and function of the mutated NEUROG3 protein were assessed by Western blot analysis and luciferase reporter assay.Results:At birth, the proband was small for gestational age. She presented for evaluation with persistent diarrhea and a poor postnatal growth pattern. Although the pancreas was present, serum amylase and fecal elastase levels were decreased, and blood glucose levels were persistently elevated by 5 months of age. Immunostaining of a small intestine biopsy for chromogranin A demonstrated complete absence of neuroendocrine cells. Genetic analysis revealed a nonsense mutation (E123X) in the region encoding helix II of the NEUROG3 gene, leading to premature termination at amino acid 123. The mutated truncated NEUROG3 protein was identified by Western blot analysis. Reporter assays show decreased transactivation of the NEUROD1 promoter by mutant NEUROG3 protein as compared to wild type.Conclusions:This report describes a newly identified nonsense mutation in human NEUROG3 that in the homozygous state is associated with neonatal diabetes and malabsorptive diarrhea.

The abnormal intrauterine milieu of intrauterine growth retardation (IUGR) permanently alters gene expression and function of pancreatic beta cells leading to the development of diabetes in adulthood. Expression of the pancreatic homeobox transcription factor Pdx1 is permanently reduced in IUGR islets suggesting an epigenetic mechanism. Exendin-4 (Ex-4), a long-acting glucagon-like peptide-1 (GLP-1) analogue, given in the newborn period increases Pdx1 expression and prevents the development of diabetes in the IUGR rat.IUGR was induced by bilateral uterine artery ligation in fetal life. Ex-4 was given on postnatal days 1-6 of life. Islets were isolated at 1 week and at 3-12 months. Histone modifications, PCAF, USF1 and DNA methyltransferase (Dnmt) 1 binding were assessed by chromatin immunoprecipitation (ChIP) assays and DNA methylation was quantified by pyrosequencing.Phosphorylation of USF1 was markedly increased in IUGR islets in Ex-4 treated animals. This resulted in increased USF1 and PCAF association at the proximal promoter of Pdx1, thereby increasing histone acetyl transferase (HAT) activity. Histone H3 acetylation and trimethylation of H3K4 were permanently increased, whereas Dnmt1 binding and subsequent DNA methylation were prevented at the proximal promoter of Pdx1 in IUGR islets. Normalisation of these epigenetic modifications reversed silencing of Pdx1 in islets of IUGR animals.These studies demonstrate a novel mechanism whereby a short treatment course of Ex-4 in the newborn period permanently increases HAT activity by recruiting USF1 and PCAF to the proximal promoter of Pdx1 which restores chromatin structure at the Pdx1 promoter and prevents DNA methylation, thus preserving Pdx1 transcription.