IGF2 DMR0 Research Articles

Paternal p,p′-DDE exposure and pre-pubertal high-fat diet increases the susceptibility to fertility impairment and sperm Igf2 DMR2 hypo-methylation in male offspring

The hypothesis of paternal origins of health and disease (POHaD) indicates that paternal exposure to adverse environment could alter the epigenetic modification in germ line, increasing the disease susceptibility in offspring or even in subsequent generations. p,p′-Dichlorodiphenyldichloroethylene (p,p′-DDE) is an anti-androgenic chemical and male reproductive toxicant. Gestational p,p′-DDE exposure could impair reproductive development and fertility in male offspring. However, the effect of paternal p,p′-DDE exposure on fertility in male offspring remains uncovered. From postnatal day (PND) 35 to 119, male rats (F0) were given 10 mg/body weight (b.w.) p,p′-DDE or corn oil by gavage. Male rats were then mated with the control females to generate male offspring. On PND35, the male offspring were divided into 4 groups according whether to be given the high-fat diet (HF): corn oil treatment with control diet (C-C), p,p′-DDE treatment with control diet (DDE-C), corn oil treatment with high-fat diet (C-HF) or p,p′-DDE treatment with high-fat diet (DDE-HF) for 35 days. Our results indicated that paternal p,p′-DDE exposure did not affect the male fertility of male offspring directly, but decreased sperm quality and induced testicular apoptosis after the high-fat diet treatment. Further analysis demonstrated that paternal exposure to p,p′-DDE and pre-pubertal high-fat diet decreased sperm Igf2 DMR2 methylation and gene expression in male offspring. Hence, paternal exposure to p,p′-DDE and pre-pubertal high-fat diet increases the susceptibility to male fertility impairment and sperm Igf2 DMR2 hypo-methylation in male offspring, posing a significant implication in the disease etiology.

Noncanonical regulation of imprinted gene Igf2 by amyloid-beta 1–42 in Alzheimer’s disease

Reduced insulin-like growth factor 2 (IGF2) levels in Alzheimer’s disease (AD) may be the mechanism relating age-related metabolic disorders to dementia. Since Igf2 is an imprinted gene, we examined age and sex differences in the relationship between amyloid-beta 1–42 (Aβ42) accumulation and epigenetic regulation of the Igf2/H19 gene cluster in cerebrum, liver, and plasma of young and old male and female 5xFAD mice, in frontal cortex of male and female AD and non-AD patients, and in HEK293 cell cultures. We show IGF2 levels, Igf2 expression, histone acetylation, and H19 ICR methylation are lower in females than males. However, elevated Aβ42 levels are associated with Aβ42 binding to Igf2 DMR2, increased DNA and histone methylation, and a reduction in Igf2 expression and IGF2 levels in 5xFAD mice and AD patients, independent of H19 ICR methylation. Cell culture results confirmed the binding of Aβ42 to Igf2 DMR2 increased DNA and histone methylation, and reduced Igf2 expression. These results indicate an age- and sex-related causal relationship among Aβ42 levels, epigenomic state, and Igf2 expression in AD and provide a potential mechanism for Igf2 regulation in normal and pathological conditions, suggesting IGF2 levels may be a useful diagnostic biomarker for Aβ42 targeted AD therapies.

Transgenerational male reproductive effect of prenatal arsenic exposure: abnormal spermatogenesis with Igf2/H19 epigenetic alteration in CD1 mouse

ABSTRACT Developmental exposure to environmental toxicants can induce transgenerational reproductive disease phenotypes through epigenetic mechanisms. We treated pregnant CD-1 (F0) mice with drinking water containing sodium arsenite (85 ppm) from days 8 to 18 of gestation. Male offspring were bred with untreated female mice until the F3 generation was produced. Our results revealed that F0 transient exposure to arsenic can cause decreased sperm quality and histological abnormalities in the F1 and F3. The overall methylation status of Igf2 DMR2 and H19 DMR was significantly lower in the arsenic-exposed group than that of the control group in both F1 and F3. The relative mRNA expression levels of Igf2 and H19 in arsenic-exposed males were significantly increased in both F1 and F3. This study indicates that ancestral exposure to arsenic may result in transgenerational inheritance of an impaired spermatogenesis phenotyping involving both epigenetic alterations and the abnormal expression of Igf2 and H19.

Role of epigenetic regulation of Igf2 and H19 in 2,3,7,8-Tetrachlorobenzo-p-dioxin (TCDD)-induced ovarian toxicity in offspring rats

2,3,7,8-Tetrachlorobenzo-p-dioxin (TCDD) exposure during embryonic gonadal sex determination had been demonstrated to harm the ovarian development. However, its mechanism was unclear and possibly related to epigenetic regulation. In the present study, the pregnant rats were treated with TCDD (100 ng/kg/day or 500 ng/kg/day) or only vehicle and corn oil on the day 8–14 of gestation through the gavage with a stainless-steel feeding needle. The vaginal opening time and estrous cycle of female offspring rats (F1) were monitored twice a day. The ovarian histology, follicle count, real-time PCR, Western Blotting and DNA methylation analysis for Igf2 and H19 were carried out. The results showed that maternal TCDD exposure disrupted estrous cyclicity, resulted in aberrant concentration of serum E2 and FSH, and affected the number of primordial follicles, secondary follicles and corpus luteum. However, TCDD had no effect on the number of primary follicles and atresia follicles. Furthermore, the mRAN expression of imprinted genes Igf2 and H19 was down-regulated, and the IGF2 protein was also down-regulated. TCDD exposure did not alter the mean methylation rate of Igf2 DMR2 and H19 ICR, and only some CpG sites throughout them were hypermethylated in high-dose TCDD rats. In conclusion, maternal exposure of TCDD could affect the ovary development and functions which were possibly associated with down-regulation expression of IGF2 and H19. However, it was not entirely clear whether the impairment of ovary by TCDD was related to the methylation pattern of Igf2 and H19 ICR.

Analysis of H19/Igf2 Methylation Status in the Sperm of Cloned Goats and Their Offspring.

The H19/insulin-like growth factor 2 (Igf2) gene plays vital roles during development, but their expression and methylation status have not been elucidated in male cloned animals. In this study, we investigated the methylation status of imprinting control region (ICR) and differentially methylated region (DMR) of the H19/Igf2 locus in the sperm and testes of naturally reproduced Saanen dairy goats (NG, control), transgenic cloned dairy goats (CG), and the first generation of mating the CGs with the female NGs (FG). Bisulfite sequencing polymerase chain reaction revealed that the H19 ICR was highly methylated in the sperm of all testing groups (97.07% ± 0.47%, 93.73% ± 0.85%, and 96.67% ± 0.54%). Notably, the methylation level of H19 ICR was decreased in the testes of CG goats compared with that of NG goats (73.83% ± 3.28% vs. 97.27% ± 0.71%, p < 0.05), while the Igf2 DMR2 was highly methylated in the sperm of these three groups (89.57% ± 1.74%, 87.23% ± 1.11%, and 83.2% ± 1.27%). However, the Igf2 DMR2 was abnormally hypomethylated in the testes of CG goats (27.33% ± 1.005%, p < 0.001), and moderately methylated in FG goats (53.1% ± 1.47%, p < 0.01) compared with that in NG goats (82.67% ± 0.70%). Furthermore, we found significantly decreased expression of H19 (p < 0.01) and increased expression of Igf2 (p < 0.01) in CG goats. Thus, we infer that somatic cell nuclear transfer has clear effect on genomic imprinting in the testes, but not sperm of cloned goats.

Methylation status of IGF2 DMR and LINE1 in leukocyte DNA provides distinct clinicopathological features of gastric cancer patients.

DNA methylation of leukocyte DNA has been proposed to be a biomarker for cancer that can be used to target patients for appropriate clinical implementation. We investigated IGF2 DMR and LINE1 methylation in the leukocyte DNA and their association with clinicopathological features and prognosis of gastric cancer (GC) patients. Methylation status of IGF2 DMR and LINE1 in the leukocyte DNA was quantified using bisulfite pyrosequencing in 207 GC patients. Methylation of both IGF2 DMR and the LINE1 was significantly higher in the undifferentiated histologic type compared to the differentiated histologic type (both P=0.0002). Hypermethylation of both the IGF2 DMR and the LINE1 was associated with more aggressive features of GC such as advanced stage (IGF2 DMR, P=0.0002; LINE1, P<0.0001), lymphatic invasion positive (IGF2 DMR, P=0.004; LINE1, P=0.002), venous invasion positive (IGF2 DMR, LINE1, both P=0.03), lymph node metastasis positive (IGF2 DMR, P=0.01; LINE1, P=0.001), peritoneal dissemination positive (IGF2 DMR, P=0.04; LINE1, P=0.002), liver metastasis positive (IGF2 DMR, P=0.008; LINE1, P=0.001), and other distant metastasis positive (IGF2 DMR, P=0.04). Our data suggest that high LINE1 and IGF2 DMR methylation status would be a phenomenon that is observed with the progression of GC, supporting their potential utility as a biomarker in GC patients.

Abstract 4930: Genetic and epigenetic characteristics of esophageal cancer tissues with microbiome fusobacterium nucleatum

Abstract Background: Research into the microbiome is a rapidly advancing field in human cancers. The gut microbiome has recently been shown to play an important role in health, as well as in diseases such as obesity, inflammatory bowel disease, diabetes, non-alcoholic fatty liver disease, and several types of cancers. Fusobacterium nucleatum is a component of the human microbiome that primarily inhabits the oral cavity. It causes periodontal disease and has also been implicated in the development of human cancers. We have recently reported that Fusobacterium nucleatum in esophageal cancer tissues was associated with shorter survival, suggesting a potential role as a prognostic biomarker. In addition, our KEGG enrichment analysis using microarray data showed that Fusobacterium nucleatum might also contribute to aggressive tumor behavior through activation of chemokines such as CCL20. Nonetheless, molecular features of Fusobacterium nucleatum-positive esophageal cancers have been still unknown. Methods: Using 325 esophageal cancers, we detected Fusobacterium nucleatum DNA in 74 tumors (23%). We assessed other genetic and epigenetic events including mutations in KRAS, BRAF, PIK3CA gene, p53 expression, phosphorylated-AKT expression, LINE-1 methylation level (global DNA methylation level), IGF2 DMR0 methylation, MGMT methylation, and MLH1 methylation. Results: The LINE-1 methylation levels of Fusobacterium nucleatum-positive tumors was significantly lower compared with that of Fusobacterium nucleatum-negative tumors (P&amp;lt;0.0001). In addition, Fusobacterium nucleatum was significantly associated with PIK3CA wild type (P=0.010). There was no relationship of Fusobacterium nucleatum with KRAS, BRAF mutation, p53 expression, p-AKT expression, IGF2 DMR0 methylation, MGMT methylation, or MLH1 methylation. Conclusion: Fusobacterium nucleatum was related with LINE-1 hypomethylation and PIK3CA wild type. Our findings may shed lights on understanding the mechanism by which Fusobacterium nucleatum affects aggressive tumor behavior. . Citation Format: Yoshifumi Baba, Kensuke Yamamura, Shigeki Nakagawa, Kosuke Mima, Takatsugu Ishimoto, Masaaki Iwatsuki, Yasuo Sakamoto, Naoya Yoshida, Hideo Baba. Genetic and epigenetic characteristics of esophageal cancer tissues with microbiome fusobacterium nucleatum [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4930. doi:10.1158/1538-7445.AM2017-4930

Maternal intake of methyl-group donors affects DNA methylation of metabolic genes in infants

BackgroundMaternal nutrition during pregnancy and infant nutrition in the early postnatal period (lactation) are critically involved in the development and health of the newborn infant. The Maternal Nutrition and Offspring’s Epigenome (MANOE) study was set up to assess the effect of maternal methyl-group donor intake (choline, betaine, folate, methionine) on infant DNA methylation. Maternal intake of dietary methyl-group donors was assessed using a food-frequency questionnaire (FFQ). Before and during pregnancy, we evaluated maternal methyl-group donor intake through diet and supplementation (folic acid) in relation to gene-specific (IGF2 DMR, DNMT1, LEP, RXRA) buccal epithelial cell DNA methylation in 6 months old infants (n = 114) via pyrosequencing. In the early postnatal period, we determined the effect of maternal choline intake during lactation (in mothers who breast-fed for at least 3 months) on gene-specific buccal DNA methylation (n = 65).ResultsMaternal dietary and supplemental intake of methyl-group donors (folate, betaine, folic acid), only in the periconception period, was associated with buccal cell DNA methylation in genes related to growth (IGF2 DMR), metabolism (RXRA), and appetite control (LEP). A negative association was found between maternal folate and folic acid intake before pregnancy and infant LEP (slope = −1.233, 95% CI −2.342; −0.125, p = 0.0298) and IGF2 DMR methylation (slope = −0.706, 95% CI −1.242; −0.107, p = 0.0101), respectively. Positive associations were observed for maternal betaine (slope = 0.875, 95% CI 0.118; 1.633, p = 0.0241) and folate (slope = 0.685, 95% CI 0.245; 1.125, p = 0.0027) intake before pregnancy and RXRA methylation. Buccal DNMT1 methylation in the infant was negatively associated with maternal methyl-group donor intake in the first and second trimester of pregnancy and negatively in the third trimester. We found no clear association between maternal choline intake during lactation and buccal infant DNA methylation.ConclusionsThis study suggests that maternal dietary and supplemental intake of methyl-group donors, especially in the periconception period, can influence infant’s buccal DNA methylation in genes related to metabolism, growth, appetite regulation, and maintenance of DNA methylation reactions.

Aberrant methylation detection of the hMLH1 promoter and the IGF2 DMR region using methylation-sensitive high resolution melting (MS-HRM) in colorectal cancer

Epigenetic alterations and gene mutations causing inactivation of tumor suppressor genes and activation of oncogenes can regulate signaling pathways contributing to colon cancer formation. Many genes have been reported to be aberrantly methylated in the CRC genome, and it is likely that only subsets of these genes are important in the pathogenesis of colorectal tumors. We applied the methylation-specific high resolution melting (MS-HRM) technique to study methylation of the IGF2 DMR and the hMLH1 gene promoter in 60 colorectal cancer and adjacent normal tissues of same patients compare to 20 normal tissue samples. In this study, 5 of the 60 colorectal cancer samples (8.3%) were found to be methylated at the hMLH1 promoter region and 32 of the 60 colorectal cancer samples (53.3%) were found to be hypomethylated at the IGF2 DMR region. Adjacent normal tissues were unmethylated for hMLH1 and 5% showed hypomethylation for IGF2 DMR. There was significant correlation between aberrant methylation of hMLH1 and IGF2 DMR with tumor location (p=0.002, p=0.026 respectively). In addition, a tendency of association between IGF2 DMR hypomethylation and age (p=0.06) was observed. We demonstrated effectiveness of the MS-HRM technique to analyze methylation of IGF2 DMR and hMLH1 promoter region and methylation significantly correlated with tumor location in colorectal cancer patients.

Aberrant methylation of imprinted genes is associated with negative hormone receptor status in invasive breast cancer

Epigenetic regulation of imprinted genes enables monoallelic expression according to parental origin, and its disruption is implicated in many cancers and developmental disorders. The expression of hormone receptors is significant in breast cancer because they are indicators of cancer cell growth rate and determine response to endocrine therapies. We investigated the frequency of aberrant events and variation in DNA methylation at nine imprinted sites in invasive breast cancer and examined the association with estrogen and progesterone receptor status. Breast tissue and blood from patients with invasive breast cancer (n = 38) and benign breast disease (n = 30) were compared with those from healthy individuals (n = 36), matched with the cancer patients by age at diagnosis, ethnicity, body mass index, menopausal status and familial history of cancer. DNA methylation and allele-specific expression were analyzed by pyrosequencing. Tumor-specific methylation changes at IGF2 DMR2 were observed in 59% of cancer patients, IGF2 DMR0 in 38%, DIRAS3 DMR in 36%, GRB10 ICR in 23%, PEG3 DMR in 21%, MEST ICR in 19%, H19 ICR in 18%, KvDMR in 8% and SNRPN/SNURF ICR in 4%. Variation in methylation was significantly greater in breast tissue from cancer patients compared with that in healthy individuals and benign breast disease. Aberrant methylation of three or more sites was significantly associated with negative estrogen-alpha (Fisher's exact test, p = 0.02) and progesterone-A (p = 0.02) receptor status. Aberrant events and increased variation in imprinted gene DNA methylation, therefore, seem to be frequent in invasive breast cancer and are associated with negative estrogen and progesterone receptor status, without loss of monoallelic expression.

Different epigenetic alterations are associated with abnormal IGF2/Igf2 upregulation in neural tube defects.

The methylation status of DNA methylation regions (DMRs) of the imprinted gene IGF2/Igf2 is associated with neural tube defects (NTDs), which are caused by a failure of the neural tube to fold and close and are the second-most common birth defect; however, the characterization of the expression level of IGF2/Igf2 in neural tissue from human fetuses affected with NTDs remains elusive. More importantly, whether abnormal chromatin structure also influences IGF2/Igf2 expression in NTDs is unclear. Here, we investigated the transcriptional activity of IGF2/Igf2 in normal and NTD spinal cord tissues, the methylation status of different DMRs, and the chromatin structure of the promoter. Our data indicated that in NTD samples from both human fetuses and retinoic acid (RA)-treated mouse fetuses, the expression level of IGF2/Igf2 was upregulated 6.41-fold and 1.84-fold, respectively, compared to controls. H19 DMR1, but not IGF2 DMR0, was hypermethylated in human NTD samples. In NTD mice, h19 DMR1 was stable, whereas the chromatin structure around the promoter of Igf2 might be loosened, which was displayed by higher H3K4 acetylation and lower H3K27 trimethylation. Therefore, the data revealed that IGF2/Igf2 expression can be ectopically up-regulated by dual epigenetic factors in NTDs. In detail, the upregulation of IGF2/Igf2 is likely controlled by hypermethylation of H19 DMR1 in human NTDs, however, in acute external RA-induced NTD mice it is potentially determined by more open chromatin structure.

Transgenerational impaired male fertility with an Igf2 epigenetic defect in the rat are induced by the endocrine disruptor p,p'-DDE.

What are the epigenetic mechanisms underlying the transgenerational effect of p,p'-DDE on male fertility? Impaired male fertility with an Igf2 epigenetic defect is transgenerationally inherited upon exposure of p,p'-DDE. p,p'-Dichlorodiphenoxydichloroethylene (p,p'-DDE) is one of the primary metabolite products of the ancestral organochlorine pesticide dichlorodiphenoxytrichloroethane. As it is a known anti-androgen endocrine disruptor, it could cause harmful effects on the male reproductive system. Pregnant rats (F0) were administered with p,p'-DDE or corn oil at the critical time of testis development, i.e. from gestation days 8 to 15. Male and female rats of the F1 generation were mated with each other to produce F2 progeny. To reveal whether the transgenerational phenotype is produced by the maternal or paternal line, F3 progeny were generated by intercrossing control (C) and treated (DDE) males and females of the F2 generation according to the following groups: (i) C♂-C♀, (ii) DDE♂-DDE♀, (iii) DDE♂-C♀ and (iv) C♂-DDE♀. Mature sperm and testes were collected from male offspring of the F1-F3 generations for the examination of male fertility parameters, i.e. sperm count and motility, testis histology and apoptosis. Expression of the imprinted genes, H19 and Igf2, was detected by real-time PCR. Igf2 DMR2 methylation was analyzed by bisulfite genomic sequencing. Upon exposure of p,p'-DDE, the male F1 generation showed impaired male fertility and altered imprinted gene expression caused by Igf2 DMR2 hypomethylation. These defects were transferred to the F3 generation through the male germline. This study has examined the effect of p,p'-DDE only on the sperm number and motility and the possible mechanism of Igf2 DMR2 methylation in vivo and thus has some limitations. Further investigation is necessary to focus on the epigenetic effects of p,p'-DDE at the genome level and to include a more detailed semen quality analysis including sperm morphology assessment. Impaired male fertility with epigenetic alterations is transgenerationally inherited after environmental exposure of p,p'-DDE, posing significant implications in the etiology of male infertility. The present research was supported by National Natural Science Fund for Young Scholar (81102161), the Natural Science Fund of Zhejiang Province (LY14H260004) and funding from the Health Department of Zhejiang Province (201475777). No competing interests are declared.

Intrauterine hyperglycemia environment alters IGF2 dmr methylation status of placenta in both first and second filial generations

Intrauterine hyperglycemia environment of gestational diabetes mellitus (GDM) could lead to abnormal gene expression of placenta in the offspring of GDM. Heritable transmission of differential gene expression may be related to epigenetic regulation. As imprinted genes, Igf2 expression in mice is regulated by allele-specific methylation at differentially methylated regions (DMRs). Therefore, the aim of our study is to examined the level of Igf2 expression in the first generation and the second generation offspring of GDM and investigate the potential epigenetic mechanism involved.

No evidence for copy number and methylation variation in H19 and KCNQ10T1 imprinting control regions in children born small for gestational age.

BackgroundThere is a substantial genetic component for birthweight variation, and although there are known associations between fetal genotype and birthweight, the role of common epigenetic variation in influencing the risk for small for gestational age (SGA) is unknown. The two imprinting control regions (ICRs) located on chromosome 11p15.5, involved in the overgrowth disorder Beckwith-Wiedemann syndrome (BWS) and the growth restriction disorder Silver-Russell syndrome (SRS), are prime epigenetic candidates for regulating fetal growth. We investigated whether common variation in copy number in the BWS/SRS 11p15 region or altered methylation levels at IGF2/H19 ICR or KCNQ10T1 ICR was associated with SGA.MethodsWe used a methylation-specific multiplex-ligation-dependent probe amplification assay to analyse copy number variation in the 11p15 region and methylation of IGF2/H19 and KCNQ10T1 ICRs in blood samples from 153 children (including 80 SGA), as well as bisulfite pyrosequencing to measure methylation at IGF2 differentially methylated region (DMR)0 and H19 DMR.ResultsNo copy number variants were detected in the analyzed cohort. Children born SGA had 2.7% lower methylation at the IGF2 DMR0. No methylation differences were detected at the H19 or KCNQ10T1 DMRs.ConclusionsWe confirm that a small hypomethylation of the IGF2 DMR0 is detected in peripheral blood leucocytes of children born SGA at term. Copy number variation within the 11p15 BWS/SRS region is not an important cause of non-syndromic SGA at term.

Dietary supplementation with polyunsaturated fatty acid during pregnancy modulates DNA methylation at IGF2/H19 imprinted genes and growth of infants (1120.3)

Epigenetic regulations of imprinted genes are highly plausible explanation for the associations of dietary exposures in early life and the onset of diseases in adulthood. We tested whether prenatal dietary supplementation with docosahexaenoic acid (DHA) during pregnancy may modulate epigenetic states at birth in a randomized intervention trial among Mexican pregnant women supplemented daily with 400 mg of DHA or a placebo from 18 to 22 week of gestation to parturition. We applied quantitative profiling of DNA methylation states at IGF2 promoter 3 (IGF2 P3), IGF2 DMR and H19 DMR in cord blood mononuclear cells of the DHA‐supplemented group (n=131) and the control group (n=130).There were no significant differences between the DHA and the control groups for DNA methylation levels at imprinted genes; however in stratified analyses, we observed a positive association between DNA methylation levels and maternal BMI; IGF2 DMR methylation was higher in the DHA than the control groups in infants from overweight mother (p=0.03) and H19 DMR, methylation levels were significantly lower in the DHA than control groups in infants from normal weight mothers (p=0.01). Prenatal DHA supplementation modulated IGF2/H19 methylation in infants and methylation levels at IGF2/H19 imprinted regions were related with maternal BMI. Epigenetic mechanism may be modulated by DHA with potential impacts on growth and development of children.Grant Funding Source: NIH‐NICHHD (RO1HD058818), NIH (RO1HDO43099) and CONACYT Mexico (SALUD‐2008‐01‐87121)

11p15 DNA-methylation analysis in monozygotic twins with discordant intrauterine development due to severe twin-to-twin transfusion syndrome

BackgroundPrenatal growth restriction and low birth weight have been linked to long-term alterations of health, presumably via adaptive modifications of the epigenome. Recent studies indicate a plasticity of the 11p15 epigenotype in response to environmental changes during early stages of human development.Study designWe analyzed methylation levels at different 11p15 loci in 20 growth-discordant monozygotic twin pairs. Intrauterine development was discordant due to severe twin-to-twin transfusion syndrome (TTTS), which was treated by fetoscopic laser coagulation of communicating vessels before 25 weeks of gestation. Methylation levels at age 4 were determined in blood and buccal cell-derived DNA by the single nucleotide primer extension reaction ion pair reverse-phase high performance liquid chromatography (SNuPE IP RP HPLC) assay. Methylation at LINE-1 repeats was analyzed as an estimate of global methylation.ResultsIn general, variance of locus-specific methylation levels appeared to be higher in buccal cell- as compared to blood cell-derived DNA samples. Paired analyses within the twin pairs revealed significant differences at only one CpG site (IGF2 dmr0 SN3 (blood), +1.9% in donors; P = 0.013). When plotting the twin pair-discordance in birth weight against the degree of discordance in site-specific methylation at age 4, only a few CpGs were found to interact (one CpG site each at IGF2dmr0 in blood/saliva DNA, one CpG at LINE-1 repeats in saliva DNA), with 26 to 36% of the intra-twin pair divergence at these sites explained by prenatal growth discordance. However, across the entire cohort of 40 children, site-specific methylation did not correlate with SD-scores for weight or length at birth. Insulin-like growth factor-II serum concentrations showed significant within-twin pair correlations at birth (R = 0.57) and at age 4 (R = 0.79), but did not differ between donors and recipients. They also did not correlate with the analyzed 11p15 methylation parameters.ConclusionIn a cohort of 20 growth-discordant monozygotic twin pairs, severe alteration in placental blood supply due to TTTS appears to leave only weak, if any, epigenetic marks at the analyzed CpG sites at 11p15.

IGF2 DMR0 Methylation, Loss of Imprinting, and Patient Prognosis in Esophageal Squamous Cell Carcinoma

Insulin like growth factor 2 gene (IGF2) is normally imprinted. Loss of imprinting (LOI) of IGF2 in humans is associated with an increased risk of cancer and is controlled by CpG-rich regions known as differentially methylated regions (DMRs). Specifically, the methylation level at IGF2 DMR0 is correlated with IGF2 LOI and is a suggested surrogate marker for IGF2 LOI. A relationship between IGF2 DMR0 hypomethylation and poor prognosis has been shown in colorectal cancer. However, to our knowledge, no study has examined the relationships among the IGF2 DMR0 methylation level, LOI, and clinical outcome in esophageal squamous cell carcinoma (ESCC). The IGF2 imprinting status was screened using ApaI polymorphism, and IGF2 protein expression was evaluated by immunohistochemistry with 30 ESCC tissue specimens. For survival analysis, IGF2 DMR0 methylation was measured using a bisulfite pyrosequencing assay with 216 ESCC tissue specimens. Twelve (40 %) of 30 cases were informative (i.e., heterozygous for ApaI), and 5 (42 %) of 12 informative cases displayed IGF2 LOI. IGF2 LOI cases exhibited lower DMR0 methylation levels (mean 23 %) than IGF2 non-LOI cases (37 %). The IGF2 DMR0 methylation level was significantly associated with IGF2 protein expression. Among 202 patients eligible for survival analysis, IGF2 DMR0 hypomethylation was significantly associated with higher cancer-specific mortality. The IGF2 DMR0 methylation level in ESCC was associated with IGF2 LOI and IGF2 protein expression. In addition, IGF2 DMR0 hypomethylation was associated with a shorter survival time, suggesting its potential role as a prognostic biomarker.

Methylation levels at IGF2 and GNAS DMRs in infants born to preeclamptic pregnancies

BackgroundOffspring of pregnancy complicated with preeclampsia are at high risk for hypertension, stroke and possibly obesity. The mechanisms behind the association of intrauterine exposure to preeclampsia and high risk of health problems in the later life remain largely unknown. The aims of the current investigation were to determine the changes in DNA methylation at IGF2 and GNAS DMR in offspring of preeclamptic pregnancy and to explore the possible mechanisms underlying the association between maternal preeclampsia and high risk for health problems in the later life of their offspring.ResultsUmbilical cord blood was taken from infants born to women of preeclampsia (n=56), gestational hypertension (n=23) and normal pregnancy (n=81). DNA methylation levels of IGF2 and GNAS DMR were determined by Massarray quantitative methylation analysis. Methylation levels at IGF2 DMR were significantly lower in preeclampsia than normal pregnancy. The average methylation level at IGF2 DMR was significantly correlated with preeclampsia even after birth weight, maternal age, gestational age at delivery and fetal gender were adjusted. The difference in methylation level was not significantly different between mild and severe preeclampsia. The methylation level at GNAS DMR was not significantly correlated with birth weight, maternal age, gestational age at delivery, fetal gender, preeclampsia or gestational hypertension.ConclusionsWe concluded preeclampsia induced a decrease in methylation level at IGF 2 DMR, and this might be among the mechanisms behind the association between intrauterine exposure to preeclampsia and high risk for metabolic diseases in the later life of the infants.

Paternal transgenerational glucose intolerance with epigenetic alterations in second generation offspring of GDM

Paternal transgenerational glucose intolerance with epigenetic alterations in second generation offspring of GDM

Association of IGF2 DMR0 hypomethylation in esophageal squamous cell carcinoma with poor prognosis.

11065 Background: The insulin-like growth factor 2 gene (IGF2) is normally imprinted. Loss of imprinting (LOI) of IGF2 in humans is associated with an increased risk of cancer and is controlled by CpG-rich regions known as differentially methylated regions (DMRs). Specifically, the methylation level at IGF2 DMR0 is correlated with IGF2 LOI and is a suggested surrogate marker for IGF2 LOI. A relationship between IGF2 DMR0 hypomethylation and poor prognosis has been shown in colorectal cancer. However, no study has examined the relationships among the IGF2 DMR0 methylation level, LOI, and clinical outcome in esophageal squamous cell carcinoma (ESCC). Methods: The IGF2 imprinting status was screened using ApaI polymorphism, and IGF2 protein expression was evaluated by immunohistochemistry with 30 ESCC tissue specimens. For survival analysis, IGF2 DMR0 methylation was measured using a bisulfite-pyrosequencing assay with 216 ESCC tissue specimens. The Cox proportional hazards model was used to calculate mortality hazard ratios (HR) adjusted for clinical, epidemiologic, and pathological variables.The term “prognostic marker” is used throughout this article according to the REMARK Guidelines. Results: Twelve (40%) of 30 cases were informative (i.e., heterozygous for ApaI), and 5 (42%) of 12 informative cases displayed IGF2 LOI. IGF2 LOI cases exhibited lower DMR0 methylation levels (mean, 23%) than IGF2 non-LOI cases (37%). The IGF2 DMR0 methylation level was significantly associated with IGF2 protein expression. Among 202 patients eligible for survival analysis, IGF2 DMR0 hypomethylation was significantly associated with higher cancer-specific mortality (log-rank P=0.013; univariate HR=2.03, 95% confidence interval: 1.14–3.58, P=0.017; multivariate HR=2.34, 95% CI: 1.29-4.22, P=0.0054). Conclusions: The IGF2 DMR0 methylation level in ESCC was associated with IGF2 LOI and IGF2 protein expression. In addition, IGF2 DMR0 hypomethylation was associated with a shorter survival time, suggesting its potential role as a prognostic biomarker.