Epigenetics最新文献

The effects of chronically stressing male mice can be transmitted across generations by stress-specific changes in their sperm miRNA content, which induce stress-specific phenotypes in their offspring. However, how each stress paradigm alters the levels of distinct sets of sperm miRNAs is not known. We showed previously that exposure of male mice to chronic social instability (CSI) stress results in elevated anxiety and reduced sociability specifically in their female offspring across multiple generations because it reduces miR-34c levels in sperm of stressed males and their unstressed male offspring. Here, we describe evidence that astrocyte-derived exosomes (A-Exos) carrying miR-34c mediate how CSI stress has this transgenerational effect on sperm. We found that CSI stress decreases miR-34c carried by A-Exos in the prefrontal cortex and amygdala, as well as in the blood of males. Importantly, miR-34c A-Exos levels are also reduced in these tissues in their F1 male offspring, who despite not being exposed to stress, exhibit reduced sperm miR-34c levels and transmit the same stress-associated traits to their male and female offspring. Furthermore, restoring A-Exos miR-34c content in the blood of CSI-stressed males by intravenous injection of miR-34c-containing A-Exos restores miR-34c levels in their sperm. These findings reveal an unexpected role for A-Exos in maintaining sperm miR-34c levels by a process that when suppressed by CSI stress mediates this example of transgenerational epigenetic inheritance.

Cervical cancer, the fourth most common cancer globally and the second most prevalent cancer among women in India, is primarily caused by Human Papilloma Virus (HPV). The association of diet with cancer etiology and prevention has been well established and nutrition has been shown to regulate cancer through modulation of epigenetic markers. Dietary fatty acids, especially omega-3, reduce the risk of cancer by preventing or reversing the progression through a variety of cellular targets, including epigenetic regulation. In this work, we have evaluated the potential of ALA (α linolenic acid), an ω-3 fatty acid, to regulate cervical cancer through epigenetic mechanisms. The effect of ALA was evaluated on the regulation of histone deacetylases1, DNA methyltransferases 1, and 3b, and global DNA methylation by ELISA. RT-PCR was utilized to assess the expression of tumor regulatory genes (hTERT, DAPK, RARβ, and CDH1) and their promoter methylation in HeLa (HPV18-positive), SiHa (HPV16-positive) and C33a (HPV-negative) cervical cancer cell lines. ALA increased DNA demethylase, HMTs, and HATs while decreasing global DNA methylation, DNMT, HDMs, and HDACs mRNA expression/activity in all cervical cancer cell lines. ALA downregulated hTERT oncogene while upregulating the mRNA expression of TSGs (Tumor Suppressor Genes) CDH1, RARβ, and DAPK in all the cell lines. ALA reduced methylation in the 5' CpG island of CDH1, RARβ, and DAPK1 promoters and reduced global DNA methylation in cervical cancer cell lines. These results suggest that ALA regulates the growth of cervical cancer cells by targeting epigenetic markers, shedding light on its potential therapeutic role in cervical cancer management.

Cirrhosis is a form of end-stage liver disease characterized by extensive hepatic fibrosis and loss of liver parenchyma. It is most commonly the result of long-term alcohol abuse in the United States. Large animal models of cirrhosis, as well as of one of its common long-term sequelae, HCC, are needed to study novel and emerging therapeutic interventions. In the present study, liver fibrosis was induced in the Oncopig cancer model, a large animal HCC model, via intrahepatic, intra-arterial ethanol infusion. Liver sections from five fibrosis induced and five age-matched controls were harvested for RNA-seq (mRNA and lncRNA), small RNA-seq (miRNA), and reduced representation bisulfite sequencing (RRBS; DNA methylation). Single- and multi-omic analysis was performed to investigate the transcriptomic and epigenomic mechanisms associated with fibrosis deposition in this model. A total of 3,439 genes, 70 miRNAs, 452 lncRNAs, and 7,715 methylation regions were found to be differentially regulated through individual single-omic analysis. Pathway analysis indicated differentially expressed genes were associated with collagen synthesis and turnover, hepatic metabolic functions such as ethanol and lipid metabolism, and proliferative and anti-proliferative pathways including PI3K and BAX/BCL signaling pathways. Multi-omic latent variable analysis demonstrated significant concordance with the single-omic analysis. lncRNA's associated with UHRF1BP1L and S1PR1 genes were found to reliably discriminate the two arms of the study. These genes were previously implicated in human cancer development and vasculogenesis, respectively. These findings support the validity and translatability of this model as a useful preclinical tool in the study of alcoholic liver disease and its treatment.

Perceived discrimination, recognized as a chronic psychosocial stressor, has adverse consequences on health. DNA methylation (DNAm) may be a potential mechanism by which stressors get embedded into the human body at the molecular level and subsequently affect health outcomes. However, relatively little is known about the effects of perceived discrimination on DNAm. To identify the DNAm sites across the epigenome that are associated with discrimination, we conducted epigenome-wide association analyses (EWAS) of three discrimination measures (everyday discrimination, race-related major discrimination, and non-race-related major discrimination) in 1,151 participants, including 565 non-Hispanic White, 221 African American, and 365 Hispanic individuals, from the Multi-Ethnic Study of Atherosclerosis (MESA). We conducted both race/ethnicity-stratified analyses as well as trans-ancestry meta-analyses. At false discovery rate of 10%, 7 CpGs and 4 differentially methylated regions (DMRs) containing 11 CpGs were associated with perceived discrimination exposures in at least one racial/ethnic group or in meta-analysis. Identified CpGs and/or nearby genes have been implicated in cellular development pathways, transcription factor binding, cancer and multiple autoimmune and/or inflammatory diseases. Of the identified CpGs (7 individual CpGs and 11 within DMRs), two CpGs and one CpG within a DMR were associated with expression of cis genes NDUFS5, AK1RIN1, NCF4 and ADSSL1. Our study demonstrated the potential influence of discrimination on DNAm and subsequent gene expression.

Poly-epigenetic scores (PEGS) are surrogate measures that help capture individual-level risk. Understanding how the associations between PEGS and cardiometabolic risk factors vary by demographics and health behaviors is crucial for lowering the burden of cardiometabolic diseases. We used results from established epigenome-wide association studies to construct trait-specific PEGS from whole blood DNA methylation for systolic and diastolic blood pressure (SBP, DBP), body mass index (BMI), C-reactive protein (CRP), high- and low-density lipoprotein cholesterol (HDL-C, LDL-C), triglycerides (TG), and fasting glucose. Overall and race-stratified associations between PEGS and corresponding traits were examined in adults >50 years from the Health and Retirement Study (n = 3,996, mean age = 79.5 years). We investigated how demographics (age, sex, educational attainment) and health behaviors (smoking, alcohol consumption, physical activity) modified these associations. All PEGS were positively associated with their corresponding cardiometabolic traits (p < 0.05), and most associations persisted across all racial/ethnic groups. Associations for BMI, HDL-C, and TG were stronger in younger participants, and BMI and HDL-C associations were stronger in females. The CRP association was stronger among those with a high school degree. Finally, the HDL-C association was stronger among current smokers. These findings support PEGS as robust surrogate measures and suggest the associations may differ among subgroups.

Lung carcinogenesis is causally linked to cigarette smoking, in part by epigenetic changes. We tested whether accumulated epigenetic change in smokers is apparent in bronchial basal cells as cells of origin of squamous cell carcinoma. Using an EM-seq platform covering 53.8 million CpGs (96% of the entire genome) at an average of 7.5 sequencing reads per CpG site at a single base resolution, we evaluated cytology-normal basal cells bronchoscopically brushed from the in situ tobacco smoke-exposed 'bronchial epithelial field' and isolated by short-term primary culture from 54 human subjects. We found that mean methylation was globally lower in ever (former and current) smokers versus never smokers (p = 0.0013) across promoters, CpG shores, exons, introns, 3'-UTRs, and intergenic regions, but not in CpG islands. Among 6mers with dinucleotides flanking CpG, those containing CGCG showed no effect from smoking, while those flanked with TT and AA displayed the strongest effects. At the gene level, smoking-related differences in methylation level were observed in CDKL1, ARTN, EDC3, CYP1B1, FAM131A, and MAGI2. Among candidate cancer genes, smoking reduced the methylation level in KRAS, ROS1, CDKN1A, CHRNB4, and CADM1. We conclude that smoking reduces long-term epigenome-wide methylation in bronchial stem cells, is impacted by the flanking sequence, and persists indefinitely beyond smoking cessation.

Gestational epigenetic aging (GEA) is a novel approach for characterizing associations between prenatal exposures and postnatal risks. Psychosocial adversity in pregnancy may influence GEA, but the molecular mechanisms are not well understood. DNA methylation to glucocorticoid regulation and hypothalamic-pituitary-adrenal (HPA) axis genes are implicated but have not been fully examined in association with GEA. This study investigated whether a polyepigenetic glucocorticoid exposure score (PGES) and HPA axis gene (NR3C1, HSD11B2, FKBP5) methylation were associated with GEA, and whether associations were sex-specific. Participants were from a prospective cohort of racial/ethnic diverse and socially disadvantaged pregnant women and infants (n = 200). DNA methylation variables were estimated using umbilical cord blood. PGES was derived with CpGs shown to be sensitive to synthetic dexamethasone exposure. NR3C1, HSD11B2, and FKBP5 methylation was summarized via factor analysis. We found that PGES (β = -1.12, SE = 0.47, p = 0.02) and several NR3C1 and FKBP5 factor scores were associated with decelerated GEA (all p < 0.05). A significant sex interaction was observed for FKBP5 factor score 3 (β = -0.34, SE = 0.15, p = 0.02) suggesting decelerated GEA for males but not females. This study showed that glucocorticoid regulation-related DNA methylation was associated with a decelerated aging phenotype at birth that might indicate a neonatal risk.

We performed an integrated analysis of genome-wide DNA methylation and expression datasets in normal cells and healthy animals exposed to polyphenols with estrogenic activity (i.e. phytoestrogens). We identified that phytoestrogens target genes linked to disrupted cellular homeostasis, e.g. genes limiting DNA break repair (RNF169) or promoting ribosomal biogenesis (rDNA). Existing evidence suggests that DNA methylation may be governed by sirtuin 1 (SIRT1) deacetylase via interactions with DNA methylating enzymes, specifically DNMT3B. Since SIRT1 was reported to be regulated by phytoestrogens, we test whether phytoestrogens suppress genes related to disrupted homeostasis via SIRT1/DNMT3B-mediated transcriptional silencing. Human MCF10A mammary epithelial cells were treated with phytoestrogens, pterostilbene (PTS) or genistein (GEN), followed by analysis of cell growth, DNA methylation, gene expression, and SIRT1/DNMT3B binding. SIRT1 occupancy at the selected phytoestrogen-target genes, RNF169 and rDNA, was accompanied by consistent promoter hypermethylation and gene downregulation in response to GEN, but not PTS. GEN-mediated hypermethylation and SIRT1 binding were linked to a robust DNMT3B enrichment at RNF169 and rDNA promoters. This was not observed in cells exposed to PTS, suggesting a distinct mechanism of action. Although both SIRT1 and DNMT3B bind to RNF169 and rDNA promoters upon GEN, the two proteins do not co-occupy the regions. Depletion of SIRT1 abolishes GEN-mediated decrease in rDNA expression, suggesting SIRT1-dependent epigenetic suppression of rDNA by GEN. These findings enhance our understanding of the role of SIRT1-DNMT3B interplay in epigenetic mechanisms mediating the impact of phytoestrogens on cell biology and cellular homeostasis.

Fetal growth restriction (FGR) is associated with perinatal death and adverse birth outcomes, as well as long-term complications, including increased childhood morbidity, abnormal neurodevelopment, and cardio-metabolic diseases in adulthood. Placental epigenetic reprogramming associated with FGR may mediate these long-term outcomes. Placental malaria (PM), characterized by sequestration of Plasmodium falciparum-infected erythrocytes in placental intervillous space, is the leading global cause of FGR, but its impact on placental epigenetics is unknown. We hypothesized that placental methylomic profiling would reveal common and distinct mechanistic pathways of non-malarial and PM-associated FGR. We analyzed placentas from a US cohort with no malaria exposure (n = 12) and a cohort from eastern Uganda, a region with a high prevalence of malaria (n = 12). From each site, 8 cases of FGR and 4 healthy controls were analyzed. PM was diagnosed by placental histopathology. We compared the methylation levels of over 850K CpGs of the placentas using Infinium MethylationEPIC v1 microarray. Non-malarial FGR was associated with 65 differentially methylated CpGs (DMCs), whereas PM-FGR was associated with 133 DMCs, compared to their corresponding controls without FGR. One DMC (cg16389901, located in the promoter region of BMP4) was commonly hypomethylated in both groups. We identified 522 DMCs between non-malarial FGR vs. PM-FGR placentas, independent of differing geographic location or cellular composition. Placentas with PM-associated FGR have distinct methylation profiles compared to placentas with non-malarial FGR, suggesting novel epigenetic reprogramming in response to malaria. Larger cohort studies are needed to determine the distinct long-term health outcomes in PM-associated FGR pregnancies.

Menstrual effluent cell profiles have potential as noninvasive biomarkers of female reproductive and gynecological health and disease. We used DNA methylation-based cell type deconvolution (methylation cytometry) to identify cell type profiles in self-collected menstrual effluent. During the second day of their menstrual cycle, healthy participants collected menstrual effluent using a vaginal swab, menstrual cup, and pad. Immune cell proportions were highest in menstrual cup samples, and epithelial cells were highest in swab samples. Our work demonstrates the feasibility and utility of menstrual effluent cell profiling in population-level research using remotely collected samples and DNA methylation.