DNA methylation study of fetus genome through a genome-wide analysis

Genome-wide analysis reveals porcine LIFR regulated by DNA methylation promotes the implantation process via the STAT3 signaling

Embryo-uterine interaction during embryo implantation depends on the coordinated expression of numerous genes in the receptive endometrium. While DNA methylation is known to play a significant role in controlling gene expression, specific molecular mechanisms underlying this regulatory event remain elusive in early porcine pregnancy. Here, we investigated the genome-wide DNA methylation landscape in the Yorkshire and Meishan pig's endometrium. The results revealed a higher degree of DNA methylation modifications on gene promoter regions on day 32 of pregnancy compared to that on day 18 of pregnancy. By integrating the mRNA and methylation profiles, leukemia inhibitory factor receptor (LIFR) was identified as a differentially methylated and expressed gene, crucial in early pregnancy. LIFR expression is epigenetically silenced via promoter hypermethylation from days 18 to 32 of pregnancy. Moreover, functional assays demonstrated that LIFR knockdown inhibited the proliferation, adhesion, and migration of endometrial epithelial cells (EECs) and downregulated the expression of STAT3 signaling and pregnancy-related genes. In vivo studies further revealed a reduction of implanted mouse embryos upon loss of function of LIFR. Furthermore, RUNX1 up-regulates LIFR expression by binding to the differentially methylated region (DMR) of the LIFR promoter. High levels of RUNX1T1, in turn, recruit RUNX1/HDAC1/DNMTs to assemble a regulatory complex that silences LIFR expression through the same locus. Collectively, our findings shed light on the role of dynamic DNA methylation and the epigenetic regulation of LIFR on embryo implantation in early swine pregnancy.

Impact of mothers' early life exposure to low or high folate on progeny outcome and DNA methylation patterns

The dynamic patterning of DNA and histone methylation during oocyte development presents a potentially susceptible time for epigenetic disruption due to early life environmental exposure of future mothers. We investigated whether maternal exposure to folic acid deficient and supplemented diets starting in utero could affect oocytes and cause adverse developmental and epigenetic effects in next generation progeny. Female BALB/c mice (F0) were placed on one of four amino acid defined diets for 4 weeks before pregnancy and throughout gestation and lactation: folic acid control (rodent recommended daily intake; Ctrl), 7-fold folic acid deficient, 10-fold folic acid supplemented or 20-fold folic acid supplemented diets. F1 female pups were weaned onto Ctrl diets, mated to produce the F2 generation and the F2 offspring were examined at E18.5 for developmental and epigenetic abnormalities. Resorption rates were increased and litter sizes decreased amongst F2 E18.5-day litters in the 20-fold folic acid supplemented group. Increases in abnormal embryo outcomes were observed in all three folic acid deficient and supplemented groups. Subtle genome-wide DNA methylation alterations were found in the placentas and brains of F2 offspring in the 7-fold folic acid deficient , 10-fold folic acid supplemented and 20-fold folic acid supplemented groups; in contrast, global and imprinted gene methylation were not affected. The findings show that early life female environmental exposures to both low and high folate prior to oocyte maturation can compromise oocyte quality, adversely affecting offspring of the next generation, in part by altering DNA methylation patterns.

Maternal depression during pregnancy and cord blood DNA methylation: findings from the Avon Longitudinal Study of Parents and Children

Up to 13% of women may experience symptoms of depression during pregnancy or in the postpartum period. Depression during pregnancy has been associated with an increased risk of adverse neurodevelopmental outcomes in the child and epigenetic mechanisms could be one of the biological pathways to explain this association. In 844 mother-child pairs from the Avon Longitudinal Study of Parents and Children, we carried out an epigenome-wide association study (EWAS) to investigate associations between prospectively collected data on maternal depression ascertained by the Edinburgh Postnatal Depression Scale in pregnancy and DNA methylation in the cord blood of newborn offspring. In individual site analysis, we identified two CpG sites associated with maternal depression in the middle part of pregnancy. In our regional analysis, we identified 39 differentially methylated regions (DMRs). Seven DMRs were associated with depression at any time point during pregnancy, 7 associated with depression in mid-pregnancy, 23 were associated with depression in late pregnancy, and 2 DMRs were associated with depression throughout pregnancy. Several of these map to genes associated with psychiatric disease and brain development. We attempted replication in The Generation R Study and could not replicate our results. Although our findings in ALSPAC suggest that maternal depression could be associated with cord blood DNA methylation the results should be viewed as preliminary and hypothesis generating until further replicated in a larger sample.

J, Chu AY, Bragg-Gresham JL, van Dongen J, Huffman JE, Ahluwalia TS, Cadby G, Eklund N, Eriksson J, Esko T, Feitosa MF, Goel A, Gorski M, Hayward C, Heard-Costa NL, Jackson AU, Jokinen E, Kanoni S, Kristiansson K, Kutalik Z, Lahti J, Luan J, Mägi R, Mahajan A, Mangino M, Medina-Gomez C, Monda KL, Nolte IM, Pérusse L, Prokopenko I, Qi L, Rose LM, Salvi E, Smith MT, Snieder H, Stančáková A, Ju Sung Y, Tachmazidou I, Teumer A, Thorleifsson G, van der Harst P, Walker RW, Wang SR, Wild SH, Willems SM, Wong A, Zhang W, Albrecht E, Couto Alves A, Bakker SJL, Barlassina C, Bartz TM, Beilby J, Bellis C, Bergman RN, Bergmann S, Blangero J, Blüher M, Boerwinkle E, Bonnycastle LL, Bornstein SR, Bruinenberg M, Campbell H, Chen YDI, Chiang CWK, Chines PS, Collins FS, Cucca F, Cupples LA, D'Avila F, de Geus EJ.C, Dedoussis G, Dimitriou M, Döring A, Eriksson JG, Farmaki AE, Farrall M, Ferreira T, Fischer K, Forouhi NG, Friedrich N, Gjesing AP, Glorioso N, Graff M, Grallert H, Grarup N, Gräßler J, Grewal J, Hamsten A, Harder MN, Hartman CA, Hassinen M, Hastie N, Hattersley AT, Havulinna AS, Heliövaara M, Hillege H, Hofman A, Holmen O, Homuth G, Hottenga JJ, Hui J, Husemoen LL, Hysi PG, Isaacs A, Ittermann T, Jalilzadeh S, James AL, Jørgensen T, Jousilahti P, Jula A, Marie Justesen J, Justice AE, Kähönen M, Karaleftheri M, Tee Khaw K, Keinanen-Kiukaanniemi SM, Kinnunen L, Knekt PB, Koistinen HA, Kolcic I, Kooner IK, Koskinen S, Kovacs P, Kyriakou T, Laitinen T, Langenberg C, Lewin AM, Lichtner P, Lindgren CM, Lindström J, Linneberg A, Lorbeer R, Lorentzon M, Luben R, Lyssenko V, Männistö S, Manunta P, Leach IM, McArdle WL, Mcknight B, Mohlke KL, Mihailov E, Milani L, Mills R, Montasser ME, Morris AP, Müller G, Musk AW, Narisu N, Ong KK, Oostra BA, Osmond C, Palotie A, Pankow JS, Paternoster L, Penninx BW, Pichler I, Pilia MG, Polašek O, Pramstaller PP, Raitakari OT, Rankinen T, Rao DC, Rayner NW, Ribel-Madsen R, Rice TK, Richards M, Ridker PM, Rivadeneira F, Ryan KA, Sanna S, Sarzynski MA, Scholtens S, Scott RA, Sebert S, Southam L, Sparsø TH, Steinthorsdottir V, Stirrups K, Stolk RP, Strauch K, Stringham HM, Swertz MA, Swift AJ, Tönjes A, Tsafantakis E, van der Most PJ, Van Vliet-Ostaptchouk JV, Vandenput L, Vartiainen E, Venturini C, Verweij N, Viikari JS, Vitart V, Vohl MC, Vonk JM, Waeber G, Widén E, Willemsen G, Wilsgaard T, Winkler TW, Wright AF, Yerges-Armstrong LM, Hua Zhao J, Carola Zillikens M, Boomsma DI, Bouchard C, Chambers JC, Chasman DI, Cusi D, Gansevoort RT, Gieger C, Hansen T, Hicks AA, Hu F, Hveem K, Jarvelin MR, Kajantie E, Kooner JS, Kuh D, Kuusisto J, Laakso M, Lakka TA, Lehtimäki T, Metspalu A, Njølstad I, Ohlsson C, Oldehinkel AJ, Palmer LJ, Pedersen O, Perola M, Peters A, Psaty BM, Puolijoki H, Rauramaa R, Rudan I, Salomaa V, Schwarz PEH, Shudiner AR, Smit JH, Sørensen TIA, Spector TD, Stefansson K, Stumvoll M, Tremblay A, Tuomilehto J, Uitterlinden AG, Uusitupa M, Völker U, Vollenweider P, Wareham NJ, Watkins H, Wilson JF, Zeggini E, Abecasis GR, Boehnke M, Borecki IB, Deloukas P, van Duijn CM, Fox C, Groop LC, Heid IM, Hunter DJ, Kaplan RC, McCarthy MI, North KE, O'Connell JR, Schlessinger D, Thorsteinsdottir U, Strachan DP, Frayling T, Hirschhorn JN, Müller-Nurasyid M, Loos RJF. A principal component meta-analysis on multiple anthropometric traits identifies novel loci for body shape

Large consortia have revealed hundreds of genetic loci associated with anthropometric traits, one trait at a time. We examined whether genetic variants affect body shape as a composite phenotype that is represented by a combination of anthropometric traits. We developed an approach that calculates averaged PCs (AvPCs) representing body shape derived from six anthropometric traits (body mass index, height, weight, waist and hip circumference, waist-to-hip ratio). The first four AvPCs explain >99% of the variability, are heritable, and associate with cardiometabolic outcomes. We performed genome-wide association analyses for each body shape composite phenotype across 65 studies and meta-analysed summary statistics. We identify six novel loci: LEMD2 and CD47 for AvPC1, RPS6KA5/C14orf159 and GANAB for AvPC3, and ARL15 and ANP32 for AvPC4. Our findings highlight the value of using multiple traits to define complex phenotypes for discovery, which are not captured by single-trait analyses, and may shed light onto new pathways.

Spontaneous Preterm Delivery, Particularly with Reduced Fetal Growth, is Associated with DNA Hypomethylation of Tumor Related Genes

Background

Preterm delivery and sub-optimal fetal growth are associated with each other and affect both mother and infant. Our aim was to determine (i) whether there are detectable differences in DNA methylation between early and late gestation and (ii) whether changes in DNA methylation from entry are associated with spontaneous preterm delivery with and without reduced fetal growth.

Methods

We conducted a case-control study nested within a large prospective cohort. Gene specific methylation was measured by Methyl-Profiler PCR Array in a Human Breast Cancer Signature Panel of 24 genes from maternal peripheral leukocytes genomic DNA at entry and 3^rd trimester (sampled at 16 and 30 weeks of gestation, respectively). Clonal bisulfite DNA sequencing was performed to confirm the changes in selected genes (CYP1B1, GADD45A and CXCL12). Multivariable analysis was used for data analysis.

Results

There was significantly decrease in DNA methylation in 15 of 24 genes during the 3^rd trimester in cases of spontaneous preterm delivery (n=23) as compared to the controls (n=19) (p<0.05–p<0.01 for each gene). Similar results were observed by bisulfite sequencing for 3 genes. The change in DNA methylation between late and early gestation was significantly different in cases (overall decrease in methylation was −4.0 ± 1.5%) compared to the controls (overall increase in methylation was 12.6 ± 2.19%, p<0.0001). A graded pattern of DNA methylation was observed in 15 genes. Cases who delivered preterm with reduced fetal growth had the lowest level of methylation, cases delivering preterm without reduced fetal growth were next and term controls were highest in methylation (p for trend <0.05 to p<0.01 for each gene). Cases of preterm delivery also had significantly lower dietary choline intake.

Conclusions

These data suggest that epigenetic modification is associated with an increased risk of spontaneous preterm delivery, spontaneous preterm delivery with reduced fetal growth in particular.

Reactivation of CDX2 in Gastric Cancer as Mark for Gene Silencing Memory

To explore the epigenetic mechanism that reactivates CDX2 (a homeobox transcription factor that serves as a tumor-suppressor gene) in intestinal-type gastric cancer during cancer progression, we examined the methylation status of the CDX2 gene promoter and the expression pattern of methyl-CpG binding protein-2 (MeCP2). From archives of the pathology records of surgically excised advanced stomach cancer cases in the Department of Molecular Pathology, Ehime University in a past decate (n=265), 10 cases of intestinal-type tubular adenocarcinoma, well-differentiated type (wel) with minor poorly-differentiated adenocarcinoma (por) components were selected. The expression pattern of CDX2, MUC2 and MeCP2 in these 10 cases was analyzed by immunohistochemistry. The cancerous and non-cancerous areas were selectively obtained by microdissection, and the methylation status of the CDX2 promoter of each area was assessed by methylation-specific polymerase chain reaction (MSP). In all 10 cases, CDX2 expression was clearly observed in the nucleus of the non-cancerous background of the intestinal metaplasic area, where the unmethylation pattern of the CDX2 gene promoter prevailed with reduced MeCP2 expression. In this metaplastic area, CDX2 expression was co-localized with its target gene, MUC2. CDX2 expression then disappeared from the deep invasive wel area. Reflecting the reduced CDX2 expression, microdissected samples from all the wel areas showed hypermethylation of the CDX2 gene promoter by MSP, with prominent MeCP2 expression. Interestingly, while hypermethylation of the CDX2 gene promoter was maintained in the por area in 8 of the 10 cases, CDX2 expression was restored in por areas where MeCP2 expression was markedly and selectively reduced. The other two cases, however, showed a constant MeCP2 expression level comparable to the surrounding deep invasive wel area with negative CDX2 expression. Therefore, gene silencing by hypermethylation may be overcome by the reduction of methyl-CpG binding proteins, resulting in apparent but non-functional reactivation of CDX2 as a mere molecular mark for gene silencing memory.