Epigenomes

16 pages, 2789 KiB

Open AccessArticle

Epigenome-Wide and Methylation Risk Score Analysis of Body Mass Index Among People with HIV

by Nanzha Abi, Alexandra Young, Pradeep Tiwari, Junyu Chen, Chang Liu, Qin Hui, Kaku So-Armah, Matthew S. Freiberg, Amy C. Justice, Ke Xu, Marta Gwinn, Vincent C. Marconi and Yan V. Sun

Epigenomes 2024, 8(4), 46; https://doi.org/10.3390/epigenomes8040046 - 12 Dec 2024

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Abstract

Background/Objectives: People with HIV (PWH) on antiretroviral therapy (ART) often gain weight, which increases their risk of type 2 diabetes and cardiovascular disease. The role of DNA methylation (DNAm) markers in obesity among PWH is understudied. This research explores the relationship between body [...] Read more.

Background/Objectives: People with HIV (PWH) on antiretroviral therapy (ART) often gain weight, which increases their risk of type 2 diabetes and cardiovascular disease. The role of DNA methylation (DNAm) markers in obesity among PWH is understudied. This research explores the relationship between body mass index (BMI) and epigenetic patterns to better understand and manage obesity-related risks in PWH. Methods: We conducted an epigenome-wide association study (EWAS) on 892 African American male PWH from the Veterans Aging Cohort Study, examining BMI associations with DNAm using linear mixed models, adjusting for covariates, including soluble CD14. We compared our results with BMI-associated DNAm markers from non-HIV individuals and developed a methylation risk score (MRS) for BMI using machine learning and a cross-validation approach. Results: We identified four epigenome-wide significant CpG sites, including one in the RAP1B gene, indicating shared and unique BMI-related epigenetic markers between PWH and non-HIV individuals. The constructed BMI MRS explained approximately 19% of the BMI variance in PWH. Conclusions: DNAm markers and MRS are significantly linked to BMI in PWH, suggesting shared and distinct molecular mechanisms with non-HIV populations. These insights could lead to targeted interventions to reduce cardiometabolic disease risks in PWH under ART. Full article

(This article belongs to the Collection Epigenetic Mechanisms in Diabetes Research)

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16 pages, 1855 KiB

Open AccessArticle

DNA Imprinting and Differentially Expressed Genes in Longissimus thoracis Muscle of Bos indicus Submitted to Early Weaning Management

by Gustavo Tinoco, Gustavo Russo, Rogério Curi, Marcelo Vicari, Paloma Melo, Isabella Souza, Juliana Torrecilhas, Philipe Moriel, Welder Baldassini, Luis Chardulo, Otávio Neto and Guilherme Pereira

Epigenomes 2024, 8(4), 45; https://doi.org/10.3390/epigenomes8040045 - 4 Dec 2024

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Abstract

Background/Objectives: Early weaning management followed by energy supplementation can lead to metabolic alterations in the calf that exert long-term effects on the animal’s health and performance. It is believed that the main molecular basis underlying these metabolic adaptations are epigenetic mechanisms that regulate, [...] Read more.

Background/Objectives: Early weaning management followed by energy supplementation can lead to metabolic alterations in the calf that exert long-term effects on the animal’s health and performance. It is believed that the main molecular basis underlying these metabolic adaptations are epigenetic mechanisms that regulate, activate, or silence genes at different stages of development and/or in response to different environmental stimuli. However, little is known about postnatal metabolic programming in Bos indicus. Therefore, this study aimed to compare the DNA methylation profile of Nellore animals submitted to conventional and early weaning and to correlate the findings with genes differentially expressed in the Longissimus thoracis skeletal muscle of Bos indicus cattle. Methods: For this, we used Reduced Representation Bisulfite Sequencing (RRBS) and RNA-Sequencing techniques to prospect differentially methylated genes (DMGs). Results: A total of 481 differentially methylated regions were identified, with 52% (250) being hypermethylated and 48% (231) hypomethylated. Functional enrichment analysis of 53 differentially methylated and differentially expressed genes was performed. The main enriched terms and pathways were associated with 3′-5′-cyclic adenosine monophosphate (cAMP) signaling, which presents the upregulated adenylate cyclase 3 (ADCY3) gene and significatively hypomethylated in the promoter region. Alterations in cAMP signaling are involved in numerous processes, many of them related to lipid metabolism. The relative differential expression of key genes of this pathway demonstrates the relationship between cAMP signaling and de novo lipogenesis. Conclusions: These findings suggest an important role of postnatal metabolic programming through DNA methylation mechanisms in determining fat deposition in beef. Full article

(This article belongs to the Collection Feature Papers in Epigenomes)

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18 pages, 1760 KiB

Open AccessArticle

Environmental Factor Index (EFI): A Novel Approach to Measure the Strength of Environmental Influence on DNA Methylation in Identical Twins

by Yoichi Takenaka, Osaka Twin Research Group and Mikio Watanabe

Epigenomes 2024, 8(4), 44; https://doi.org/10.3390/epigenomes8040044 - 21 Nov 2024

Cited by 1 | Viewed by 866

Abstract

Background/Objectives: The dynamic interaction between genomic DNA, epigenetic modifications, and phenotypic traits was examined in identical twins. Environmental perturbations can induce epigenetic changes in DNA methylation, influencing gene expression and phenotypes. Although DNA methylation mediates gene-environment correlations, the quantitative effects of external factors [...] Read more.

Background/Objectives: The dynamic interaction between genomic DNA, epigenetic modifications, and phenotypic traits was examined in identical twins. Environmental perturbations can induce epigenetic changes in DNA methylation, influencing gene expression and phenotypes. Although DNA methylation mediates gene-environment correlations, the quantitative effects of external factors on DNA methylation remain underexplored. This study aimed to quantify these effects using a novel approach. Methods: A cohort study was conducted on healthy monozygotic twins to evaluate the influence of environmental stimuli on DNA methylation. We developed the Environmental Factor Index (EFI) to identify methylation sites showing statistically significant changes in response to environmental stimuli. We analyzed the identified sites for associations with disorders, DNA methylation markers, and CpG islands. Results: The EFI identified methylation sites that exhibited significant associations with genes linked to various disorders, particularly cancer. These sites were overrepresented on CpG islands compared to other genomic features, highlighting their regulatory importance. Conclusions: The EFI is a valuable tool for understanding the molecular mechanisms underlying disease pathogenesis. It provides insights into the development of preventive and therapeutic strategies and offers a new perspective on the role of environmental factors in epigenetic regulation. Full article

(This article belongs to the Collection Feature Papers in Epigenomes)

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10 pages, 1876 KiB

Open AccessArticle

Age-Dependent DNA Methylation Variability on the X-Chromosome in Male and Female Twins

by Qihua Tan, Hikmat Alo, Marianne Nygaard, Mette Sørensen, Alisa Saleh, Jonas Mengel-From and Kaare Christensen

Epigenomes 2024, 8(4), 43; https://doi.org/10.3390/epigenomes8040043 - 18 Nov 2024

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Abstract

We aimed to explore the age-dependent epigenetic variability on the X-chromosome with consideration of X-chromosome inactivation by applying a sex-stratified regression analysis to DNA methylation array data on X-linked CpGs in aging identical twins. We found 13 X-linked CpGs showing age-related significant increase [...] Read more.

We aimed to explore the age-dependent epigenetic variability on the X-chromosome with consideration of X-chromosome inactivation by applying a sex-stratified regression analysis to DNA methylation array data on X-linked CpGs in aging identical twins. We found 13 X-linked CpGs showing age-related significant increase in variability in males (FDR < 0.05) but none in females. In females, we found a significantly higher proportion of CpGs showing increased variability with age among nominally significant (p < 0.05) CpGs under inactivation, but not among CpGs escaping inactivation. Survival analysis showed a slight trend of correlation by directional change in the variable CpGs with mortality in males. Compared with females, the male X-chromosome can be more vulnerable to epigenetic instability during aging. Full article

(This article belongs to the Special Issue X-Chromosome Inactivation)

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8 pages, 694 KiB

Open AccessOpinion

Histone Modification Pathways Suppressing Cryptic Transcription

by Hong-Yeoul Ryu

Epigenomes 2024, 8(4), 42; https://doi.org/10.3390/epigenomes8040042 - 12 Nov 2024

Viewed by 1081

Abstract

Cryptic transcription refers to the unintended expression of non-canonical sites within the genome, producing aberrant RNA and proteins that may disrupt cellular functions. In this opinion piece, I will explore the role of histone modifications in modulating cryptic transcription and its implications for [...] Read more.

Cryptic transcription refers to the unintended expression of non-canonical sites within the genome, producing aberrant RNA and proteins that may disrupt cellular functions. In this opinion piece, I will explore the role of histone modifications in modulating cryptic transcription and its implications for gene expression and cellular integrity, particularly with a focus on H3K36 and H3K4 methylation marks. H3K36 tri-methylation plays a crucial role in maintaining chromatin integrity by facilitating the recruitment of the Rpd3S histone deacetylase (HDAC) complex, which helps restore closed chromatin states following transcription and prevents cryptic initiation within gene bodies. In parallel, crosstalk between H3K4 di-methylation and histone ubiquitylation and sumoylation is critical for recruiting the Set3 HDAC complex, which maintains low histone acetylation levels in gene bodies and further suppresses cryptic transcription. Therefore, by elucidating these regulatory mechanisms, this opinion highlights the intricate interplay of histone modifications in preserving transcriptional fidelity and suggests potential pathways for future research to develop novel therapies for age-related disorders and other diseases associated with dysregulated gene expression. Full article

(This article belongs to the Special Issue Histone Variants)

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12 pages, 883 KiB

Open AccessReview

Epigenetic Landscape of DNA Methylation in Pancreatic Ductal Adenocarcinoma

by Peiyi Liu, Juliette Jacques and Chang-Il Hwang

Epigenomes 2024, 8(4), 41; https://doi.org/10.3390/epigenomes8040041 - 3 Nov 2024

Viewed by 1461

Abstract

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, characterized by its aggressive progression and dismal prognosis. Advances in epigenetic profiling, specifically DNA methylation analysis, have significantly deepened our understanding of PDAC pathogenesis. This review synthesizes findings from recent genome-wide DNA [...] Read more.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, characterized by its aggressive progression and dismal prognosis. Advances in epigenetic profiling, specifically DNA methylation analysis, have significantly deepened our understanding of PDAC pathogenesis. This review synthesizes findings from recent genome-wide DNA methylation studies, which have delineated a complex DNA methylation landscape differentiating between normal and cancerous pancreatic tissues, as well as across various stages and molecular subtypes of PDAC. These studies identified specific differentially methylated regions (DMRs) that not only enhance our grasp of the epigenetic drivers of PDAC but also offer potential biomarkers for early diagnosis and prognosis, enabling the customization of therapeutic approaches. The review further explores how DNA methylation profiling could facilitate the development of subtype-tailored therapies, potentially improving treatment outcomes based on precise molecular characterizations. Overall, leveraging DNA methylation alterations as functional biomarkers holds promise for advancing our understanding of disease progression and refining PDAC management strategies, which could lead to improved patient outcomes and a deeper comprehension of the disease’s underlying biological mechanisms. Full article

(This article belongs to the Special Issue New Insights into Epigenetic Regulation in Cancer)

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16 pages, 3119 KiB

Open AccessArticle

Transcription Factors Are Involved in Wizened Bud Occurrence During the Growing Season in the Pyrus pyrifolia Cultivar ‘Sucui 1’

by Hui Li, Jialiang Kan, Chunxiao Liu, Qingsong Yang, Jing Lin and Xiaogang Li

Epigenomes 2024, 8(4), 40; https://doi.org/10.3390/epigenomes8040040 - 25 Oct 2024

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Abstract

Background: Flowers are important plant organs, and their development is correlated with yield in woody fruit trees. For Pyrus pyrifolia cultivar ‘Sucui 1’, the research on how DNA methylation accurately regulates the expression of TFs and affects the specific regulatory mechanism of flower [...] Read more.

Background: Flowers are important plant organs, and their development is correlated with yield in woody fruit trees. For Pyrus pyrifolia cultivar ‘Sucui 1’, the research on how DNA methylation accurately regulates the expression of TFs and affects the specific regulatory mechanism of flower bud wizening will help reduce wizened buds. Methods: Here, the DNA methylomes and transcriptomes of two types of flower buds from the Pyrus pyrifolia cultivar ‘Sucui 1’ were compared. Results: 320 differentially expressed transcription factors (TFs), in 43 families, were obtained from the wizened bud transcriptome versus the normal bud transcriptome. Most were members of the AP2/ERF, bHLH, C2H2, CO-like, MADS, MYB, and WRKY families, which are involved in flower development. As a whole, the methylation level of TFs in the ‘Sucui 1’ genome increased once flower bud wizening occurred. A cytosine methylation analysis revealed that the methylation levels of the same gene regions in TFs from two kinds of buds were similar. However, differentially methylated regions were found in gene promoter sequences. The combined whole-genome bisulfite sequencing and RNA-Seq analyses revealed 162 TF genes (including 164 differentially methylated regions) with both differential expression and methylation differences between the two flower bud types. Among them, 126 were classified as ^mCHH-type methylation genes. Furthermore, the transcriptional down regulation of PpbHLH40, PpERF4, PpERF061, PpLHW, PpMADS6, PpZF-HD11, and PpZFP90 was accompanied by increased DNA methylation. However, PpbHLH130, PpERF011, and PpMYB308 displayed the opposite trend. The expression changes for these TFs were negatively correlated with their methylation states. Conclusions: Overall, our results offer initial experimental evidence of a correlation between DNA methylation and TF transcription in P. pyrifolia in response to bud wizening. This enriched our understanding of epigenetic modulations in woody trees during flower development. Full article

(This article belongs to the Collection Epigenetic Control in Plants)

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19 pages, 11563 KiB

Open AccessArticle

Epigenome Mapping in Quiescent Cells Reveals a Key Role for H3K4me3 in Regulation of RNA Polymerase II Activity

by Shengyuan Zeng and Karl Ekwall

Epigenomes 2024, 8(4), 39; https://doi.org/10.3390/epigenomes8040039 - 22 Oct 2024

Viewed by 1331

Abstract

(1) Background: Quiescent cells are those that have stopped dividing and show strongly reduced levels of gene expression during dormancy. In response to appropriate signals, the cells can wake up and start growing again. Many histone modifications are regulated in quiescence, but their [...] Read more.

(1) Background: Quiescent cells are those that have stopped dividing and show strongly reduced levels of gene expression during dormancy. In response to appropriate signals, the cells can wake up and start growing again. Many histone modifications are regulated in quiescence, but their exact functions remain to be determined. (2) Methods: Here, we map the different histone modifications, H3K4me3, H3K9ac, H3K9me2, and H3K9me3, and the histone variant H2A.Z, comparing vegetative and quiescent fission yeast (S. pombe) cells. We also map histone H3 as a control and RNA polymerase II (phosphorylated at S2 and S5) to enable comparisons of their occupancies within genes. We use ChIP-seq methodology and several different bioinformatics tools. (3) Results: The histone modification mapping data show that H3K4me3 changes stand out as being the most significant. Changes in occupancy of histone variant H2A.Z were also significant, consistent with earlier studies. Regarding gene expression changes in quiescence, we found that changes in mRNA levels were associated with changes in occupancy of RNA polymerase II (S2 and S5). Analysis of quiescence genes showed that increased H3K4me3 levels and RNA polymerase II occupancy were super-significant in a small set of core quiescence genes that are continuously upregulated during dormancy. We demonstrate that several of these genes were require Set1C/COMPASS activity for their strong induction during quiescence. (4) Conclusions: Our results imply that regulation of gene expression in quiescent cells involves epigenome changes with a key role for H3K4me3 in regulation of RNA polymerase II activity, and that different gene activation mechanisms control early and core quiescence genes. Thus, our data give further insights into important epigenome changes in quiescence using fission yeast as an experimental model. Full article

(This article belongs to the Special Issue Histone Variants)

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18 pages, 4934 KiB

Open AccessArticle

Associations between Circulating Biomarkers of One-Carbon Metabolism and Mitochondrial D-Loop Region Methylation Levels

by Andrea Stoccoro, Martina Lari, Lucia Migliore and Fabio Coppedè

Epigenomes 2024, 8(4), 38; https://doi.org/10.3390/epigenomes8040038 - 9 Oct 2024

Cited by 1 | Viewed by 1529

Abstract

Background/Objectives: One-carbon metabolism is a critical pathway for epigenetic mechanisms. Circulating biomarkers of one-carbon metabolism have been associated with changes in nuclear DNA methylation levels in individuals affected by age-related diseases. More and more studies are showing that even mitochondrial DNA (mtDNA) could [...] Read more.

Background/Objectives: One-carbon metabolism is a critical pathway for epigenetic mechanisms. Circulating biomarkers of one-carbon metabolism have been associated with changes in nuclear DNA methylation levels in individuals affected by age-related diseases. More and more studies are showing that even mitochondrial DNA (mtDNA) could be methylated. In particular, methylation of the mitochondrial displacement (D-loop) region modulates the gene expression and replication of mtDNA and, when altered, can contribute to the development of human illnesses. However, no study until now has demonstrated an association between circulating biomarkers of one-carbon metabolism and D-loop methylation levels. Methods: In the study presented herein, we searched for associations between circulating one-carbon metabolism biomarkers, including folate, homocysteine, and vitamin B12, and the methylation levels of the D-loop region in DNA obtained from the peripheral blood of 94 elderly voluntary subjects. Results: We observed a positive correlation between D-loop methylation and vitamin B12 (r = 0.21; p = 0.03), while no significant correlation was observed with folate (r = 0.02; p = 0.80) or homocysteine levels (r = 0.02; p = 0.82). Moreover, D-loop methylation was increased in individuals with high vitamin B12 levels compared to those with normal vitamin B12 levels (p = 0.04). Conclusions: This is the first study suggesting an association between vitamin B12 circulating levels and mtDNA methylation in human subjects. Given the potential implications of altered one-carbon metabolism and mitochondrial epigenetics in human diseases, a deeper understanding of their interaction could inspire novel interventions with beneficial effects for human health. Full article

(This article belongs to the Special Issue A Commemorative Issue in Honor of the 30th Anniversary of the Epigenetics Society)

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13 pages, 534 KiB

Open AccessArticle

Examining the Utility of the Mammalian Methylation Array for Pan-Mammalian Analysis of Monozygotic Twinning

by Jenny van Dongen, Charles E. Breeze and Twinning Genetics Consortium

Epigenomes 2024, 8(4), 37; https://doi.org/10.3390/epigenomes8040037 - 6 Oct 2024

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Abstract

Background/Objectives: Human identical twins are born at a rate of 3–4 per 1000 live births. Many other mammals also occasionally produce monozygotic twins, referred to as sporadic polyembryony. The underlying mechanisms are unknown. Through epigenome-wide association studies (EWAS), we identified a robust DNA [...] Read more.

Background/Objectives: Human identical twins are born at a rate of 3–4 per 1000 live births. Many other mammals also occasionally produce monozygotic twins, referred to as sporadic polyembryony. The underlying mechanisms are unknown. Through epigenome-wide association studies (EWAS), we identified a robust DNA methylation signature in somatic tissues from human monozygotic (MZ) twins, comprising 834 differentially methylated positions (MZ-DMPs). The results point to a connection between monozygotic twinning and early genome programming and enable new angles to study monozygotic twinning. Methods: The mammalian methylation array (MMA) measures 38,608 CpGs focusing on regions that are well-conserved across many mammalian species, allowing for pan-mammalian comparative epigenomic studies. Here, we successfully map human MZ-DMPs to probes of the mammalian methylation array across 157 mammalian genomes. Results: As expected, based on the modest probe overlap between Illumina 450k/EPIC and mammalian methylation array probes, only a subset of MZ-DMPs reside in conserved regions covered by the mammalian methylation array. These include probes mapping to NPAS3, KLHL35, CASZ1, and ATP2B2. Re-analysis restricting the original EWAS in humans to conserved MMA regions yielded additional MZ-DMPs, suggesting that more loci may be detected by application of the mammalian array to monozygotic twins. Conclusions: In conclusion, the mammalian methylation array may prove to be a promising platform to study whether a shared DNA methylation signature of sporadic polyembryony exists across diverse mammalian species. This may potentially point to shared underlying mechanisms. Full article

(This article belongs to the Collection Feature Papers in Epigenomes)

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Epigenomes, Volume 8, Issue 4 (December 2024) – 10 articles

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