The diverse roles of DNA methylation in mammalian development and disease

The one-carbon metabolism as an underlying pathway for placental DNA methylation - a systematic review

Epigenetic modifications, including DNA methylation, are proposed mechanisms explaining the impact of parental exposures to foetal development and lifelong health. Micronutrients including folate, choline, and vitamin B12 provide methyl groups for the one-carbon metabolism and subsequent DNA methylation processes. Placental DNA methylation changes in response to one-carbon moieties hold potential targets to improve obstetrical care. We conducted a systematic review on the associations between one-carbon metabolism and human placental DNA methylation. We included 22 studies. Findings from clinical studies with minimal ErasmusAGE quality score 5/10 (n = 15) and in vitro studies (n = 3) are summarized for different one-carbon moieties. Next, results are discussed per study approach: (1) global DNA methylation (n = 9), (2) genome-wide analyses (n = 4), and (3) gene specific (n = 14). Generally, one-carbon moieties were not associated with global methylation, although conflicting outcomes were reported specifically for choline. Using genome-wide approaches, few differentially methylated sites associated with S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), or dietary patterns. Most studies taking a gene-specific approach indicated site-specific relationships depending on studied moiety and genomic region, specifically in genes involved in growth and development including LEP, NR3C1, CRH, and PlGF; however, overlap between studies was low. Therefore, we recommend to further investigate the impact of an optimized one-carbon metabolism on DNA methylation and lifelong health.

TET1 inhibits the migration and invasion of cervical cancer cells by regulating autophagy

Methylation modifications play pertinent roles in regulating gene expression and various biological processes. The silencing of the demethylase enzyme TET1 can affect the expressions of key oncogenes or tumour suppressor genes, thus contributing to tumour formation. Nonetheless, how TET1 affects the progression of cervical cancer is yet to be elucidated. In this study, we found that the expression of TET1 was significantly downregulated in cervical cancer tissues. Functionally, TET1 knockdown in cervical cancer cells can promote cell proliferation, migration, invasion, cervical xenograft tumour formation and EMT. On the contrary, its overexpression can reverse the aforementioned processes. Moreover, the autophagy level of cervical cancer cells can be enhanced after TET1 knockdown. Mechanistically, methylated DNA immunoprecipitation (MeDIP)-sequencing and MeDIP quantitative real-time PCR revealed that TET1 mediates the methylation of autophagy promoter regions. These findings suggest that TET1 affects the autophagy of cervical cancer cells by altering the methylation levels of NKRF or HIST1H2AK, but the specific mechanism needs to be investigated further.

Global DNA methylation is not elevated in blood samples from Machado-Joseph disease mutation carriers

Machado-Joseph disease (MJD) is an autosomal dominant spinocerebellar ataxia (SCA) caused by a polyglutamine expansion in the ataxin-3 protein, which initiates a cascade of pathogenic events, including transcriptional dysregulation. Genotype-phenotype correlations in MJD are incomplete, suggesting an influence of additional factors, such as epigenetic modifications, underlying the MJD pathogenesis. DNA methylation is known to impact the pathophysiology of neurodegenerative disorders through gene expression regulation and increased methylation has been reported for other SCAs. In this work we aimed to analyse global methylation in MJD carriers. Global 5-mC levels were quantified in blood samples of 33 MJD mutation carriers (patients and preclinical subjects) and 33 healthy controls, matched by age, sex, and smoking status. For a subset of 16 MJD subjects, a pilot follow-up analysis with two time points was also conducted. No differences were found in median global 5-mC levels between MJD mutation carriers and controls and no correlations between methylation levels and clinical or genetic variables were detected. Also, no alterations in global 5-mC levels were observed over time. Our findings do not support an increase in global blood methylation levels associated with MJD.

A review on trends in development and translation of omics signatures in cancer

The field of cancer genomics and transcriptomics has evolved from targeted profiling to swift sequencing of individual tumor genome and transcriptome. The steady growth in genome, epigenome, and transcriptome datasets on a genome-wide scale has significantly increased our capability in capturing signatures that represent both the intrinsic and extrinsic biological features of tumors. These biological differences can help in precise molecular subtyping of cancer, predicting tumor progression, metastatic potential, and resistance to therapeutic agents. In this review, we summarized the current development of genomic, methylomic, transcriptomic, proteomic and metabolic signatures in the field of cancer research and highlighted their potentials in clinical applications to improve diagnosis, prognosis, and treatment decision in cancer patients.

Influence of DNA-methylation at multiple stages of limb chondrogenesis

Precise regulation of gene expression is of utmost importance during cell fate specification. DNA methylation is a key epigenetic mechanism that plays a significant role in the regulation of cell fate by recruiting repression proteins or inhibiting the binding of transcription factors to DNA to regulate gene expression. Limb development is a well-established model for understanding cell fate decisions, and the formation of skeletal elements is coordinated through a sequence of events that control chondrogenesis spatiotemporally. It has been established that epigenetic control participates in cartilage maturation. However, further investigation is required to determine its role in the earliest stages of chondrocyte differentiation. This study investigates how the DNA methylation environment affects cell fate divergence during the early chondrogenic events. Our research has shown for the first time that inhibiting DNA methylation in interdigital tissue with 5-azacytidine results in the formation of an ectopic digit. This discovery suggested that DNA methylation dynamics could regulate the fate of cells between chondrogenesis and cell death during autopod development. Our in vitro findings indicate that DNA methylation at the early stages of chondrogenesis is integral in regulating condensation by controlling cell adhesion and proapoptotic genes. As a result, the dynamics of methylation and demethylation are crucial in governing chondrogenesis and cell death during different stages of limb chondrogenesis.

Apolipoprotein A-1 downregulation promotes basal-like breast cancer cell proliferation and migration associated with DNA methylation

Apolipoprotein A-I (APOA1) performs different roles in different subtypes of breast cancer. It is hypothesized to function as a tumor suppressor in basal-like breast cancer (BLBC). However, the specific role of APOA1 in BLBC and its underlying mechanisms remain unknown. The findings of the present study demonstrated a positive correlation between the expression level of APOA1 and the overall survival of patients with BLBC. Ectopic expression of APOA1 effectively inhibits the proliferation and metastasis of BLBC cells in vitro, and these effects are closely related to DNA methylation. To the best of our knowledge, the present study is the first to report increased methylation of the promoter region and decreased methylation of the structural genes of APOA1 in BLBC cells. These alterations resulted in the downregulation of APOA1 expression and suppression of BLBC tumor growth. Collectively, the results of the present study suggested that APOA1 mRNA expression is negatively regulated by DNA methylation in BLBC. Therefore, low expression of APOA1 may be a potential risk biomarker to predict survival in patients with BLBC.

Deciphering epigenetic regulations in the inflammatory pathways of atopic dermatitis

Atopic dermatitis, commonly referred to as atopic eczema, is a persistent inflammatory skin disorder that predominantly manifests in children but may endure into adulthood. Its clinical management poses challenges due to the absence of a definitive cure, and its prevalence varies across ethnicities, genders, and geographic locations. The epigenetic landscape of AD includes changes in DNA methylation, changes in histone acetylation and methylation, and regulation by non-coding RNAs. These changes affect inflammatory and immune mechanisms, and research has identified AD-specific variations in DNA methylation, particularly in the affected epidermis. Histone modifications, including acetylation, have been associated with the disruption of skin barrier function in AD, suggesting the potential therapeutic benefit of histone deacetylase inhibitors such as belinostat. Furthermore, non-coding RNAs, particularly microRNAs and long non-coding RNAs (lncRNAs), have been implicated in modulating various cellular processes central to AD pathogenesis. Therapeutic implications in AD include the potential use of DNA methylation inhibitors and histone deacetylase inhibitors to correct aberrant methylation patterns and modulate gene expression related to immune responses and skin barrier functions. Additionally, the emerging role of lncRNAs suggests the possibility of using small interfering RNAs or antisense oligonucleotides to inhibit lncRNAs and adjust their regulatory impact on gene expression. In conclusion, the importance of epigenetic elements in AD is becoming increasingly clear as studies highlight the contribution of DNA methylation, histone modifications and, control by non-coding RNAs to the onset and progression of the disease. Understanding these epigenetic changes provides valuable insights for developing targeted therapeutic strategies.

Profiling age and body fluid DNA methylation markers using nanopore adaptive sampling

DNA methylation plays essential roles in regulating physiological processes, from tissue and organ development to gene expression and aging processes and has emerged as a widely used biomarker for the identification of body fluids and age prediction. Currently, methylation markers are targeted independently at specific CpG sites as part of a multiplexed assay rather than through a unified assay. Methylation detection is also dependent on divergent methodologies, ranging from enzyme digestion and affinity enrichment to bisulfite treatment, alongside various technologies for high-throughput profiling, including microarray and sequencing. In this pilot study, we test the simultaneous identification of age-associated and body fluid-specific methylation markers using a single technology, nanopore adaptive sampling. This innovative approach enables the profiling of multiple CpG marker sites across entire gene regions from a single sample without the need for specialized DNA preparation or additional biochemical treatments. Our study demonstrates that adaptive sampling achieves sufficient coverage in regions of interest to accurately determine the methylation status, shows a robust consistency with whole-genome bisulfite sequencing data, and corroborates known CpG markers of age and body fluids. Our work also resulted in the identification of new sites strongly correlated with age, suggesting new possible age methylation markers. This study lays the groundwork for the systematic development of nanopore-based methodologies in both age prediction and body fluid identification, highlighting the feasibility and potential of nanopore adaptive sampling while acknowledging the need for further validation and expansion in future research.

Genetic and Epigenetic Mechanisms Regulating Blood Pressure and Kidney Dysfunction

The pioneering work of Dr Lewis K. Dahl established a relationship between kidney, salt, and high blood pressure (BP), which led to the major genetic-based experimental model of hypertension. BP, a heritable quantitative trait affected by numerous biological and environmental stimuli, is a major cause of morbidity and mortality worldwide and is considered to be a primary modifiable factor in renal, cardiovascular, and cerebrovascular diseases. Genome-wide association studies have identified monogenic and polygenic variants affecting BP in humans. Single nucleotide polymorphisms identified in genome-wide association studies have quantified the heritability of BP and the effect of genetics on hypertensive phenotype. Changes in the transcriptional program of genes may represent consequential determinants of BP, so understanding the mechanisms of the disease process has become a priority in the field. At the molecular level, the onset of hypertension is associated with reprogramming of gene expression influenced by epigenomics. This review highlights the specific genetic variants, mutations, and epigenetic factors associated with high BP and how these mechanisms affect the regulation of hypertension and kidney dysfunction.

Differential methylation region detection via an array-adaptive normalized kernel-weighted model

A differentially methylated region (DMR) is a genomic region that has significantly different methylation patterns between biological conditions. Identifying DMRs between different biological conditions is critical for developing disease biomarkers. Although methods for detecting DMRs in microarray data have been introduced, developing methods with high precision, recall, and accuracy in determining the true length of DMRs remains a challenge. In this study, we propose a normalized kernel-weighted model to account for similar methylation profiles using the relative probe distance from "nearby" CpG sites. We also extend this model by proposing an array-adaptive version in attempt to account for the differences in probe spacing between Illumina's Infinium 450K and EPIC bead array respectively. We also study the asymptotic results of our proposed statistic. We compare our approach with a popular DMR detection method via simulation studies under large and small treatment effect settings. We also discuss the susceptibility of our method in detecting the true length of the DMRs under these two settings. Lastly, we demonstrate the biological usefulness of our method when combined with pathway analysis methods on oral cancer data. We have created an R package called idDMR, downloadable from GitHub repository with link: https://github.com/DanielAlhassan/idDMR, that allows for the convenient implementation of our array-adaptive DMR method.

Brainwide silencing of prion protein by AAV-mediated delivery of an engineered compact epigenetic editor

Prion disease is caused by misfolding of the prion protein (PrP) into pathogenic self-propagating conformations, leading to rapid-onset dementia and death. However, elimination of endogenous PrP halts prion disease progression. In this study, we describe Coupled Histone tail for Autoinhibition Release of Methyltransferase (CHARM), a compact, enzyme-free epigenetic editor capable of silencing transcription through programmable DNA methylation. Using a histone H3 tail-Dnmt3l fusion, CHARM recruits and activates endogenous DNA methyltransferases, thereby reducing transgene size and cytotoxicity. When delivered to the mouse brain by systemic injection of adeno-associated virus (AAV), Prnp-targeted CHARM ablates PrP expression across the brain. Furthermore, we have temporally limited editor expression by implementing a kinetically tuned self-silencing approach. CHARM potentially represents a broadly applicable strategy to suppress pathogenic proteins, including those implicated in other neurodegenerative diseases.

asteRIa enables robust interaction modeling between chromatin modifications and epigenetic readers

Chromatin, the nucleoprotein complex consisting of DNA and histone proteins, plays a crucial role in regulating gene expression by controlling access to DNA. Chromatin modifications are key players in this regulation, as they help to orchestrate DNA transcription, replication, and repair. These modifications recruit epigenetic 'reader' proteins, which mediate downstream events. Most modifications occur in distinctive combinations within a nucleosome, suggesting that epigenetic information can be encoded in combinatorial chromatin modifications. A detailed understanding of how multiple modifications cooperate in recruiting such proteins has, however, remained largely elusive. Here, we integrate nucleosome affinity purification data with high-throughput quantitative proteomics and hierarchical interaction modeling to estimate combinatorial effects of chromatin modifications on protein recruitment. This is facilitated by the computational workflow asteRIa which combines hierarchical interaction modeling, stability-based model selection, and replicate-consistency checks for a stable estimation of Robust Interactions among chromatin modifications. asteRIa identifies several epigenetic reader candidates responding to specific interactions between chromatin modifications. For the polycomb protein CBX8, we independently validate our results using genome-wide ChIP-Seq and bisulphite sequencing datasets. We provide the first quantitative framework for identifying cooperative effects of chromatin modifications on protein binding.

DNMT inhibitor, 5-aza-2'-deoxycytidine mitigates di(2-ethylhexyl) phthalate-induced aggravation of psoriasiform inflammation in mice via reduction in global DNA methylation in dermal and peripheral compartments

Psoriasis is classified as an autoimmune disorder characterized by abnormal immune response leading to the development of chronic dermal inflammation. Most individuals have a genetic vulnerability that may be further influenced by epigenetic changes occurring due to multiple variables such as pollutant exposure. Epigenetic modifications such as DNA methylation possess a dynamic nature, enabling cellular differentiation and adaptation by controlling gene expression. Di(2-ethylhexyl) phthalate (DEHP) and psoriatic inflammation are known to cause modification of DNA methylation via DNA methyltransferase (DNMT). However, it is not known whether DEHP, a ubiquitous plasticizer affects psoriatic inflammation via DNMT modulation. Therefore, this study investigated the effect of DNMT inhibitor, 5-aza-2'-deoxycytidine (AZA) on DEHP-induced changes in the expression of DNMT1, global DNA methylation, and anti-/inflammatory parameters (p-STAT3, IL-17A, IL-6, iNOS, IL-10, Foxp3, Nrf2, HO-1) in the skin and the peripheral adaptive/ myeloid immune cells (CD4+ T cells/CD11b+ cells) in imiquimod (IMQ) model of psoriasiform inflammation. Further, psoriasis-associated clinical/histopathological features (ear thickness, ear weight, ear PASI score, MPO activity, and H&E staining of the ear and the back skin) were also analyzed in IMQ model. Our data show that IMQ-treated mice with DEHP exposure had increased DNMT1 expression and DNA methylation which was associated with elevated inflammatory (p-STAT3, IL-17A, IL-6, iNOS) and downregulated anti-inflammatory mediators (IL-10, Foxp3, Nrf2, HO-1) in the peripheral immune cells (CD4+ T cells/CD11b+ cells) and the skin as compared to IMQ-treated mice. Treatment with DNMT1 inhibitor caused reduction in inflammatory and elevation in anti-inflammatory parameters with significant improvement in clinical/histopathological symptoms in both IMQ-treated and DEHP-exposed IMQ-treated mice. In conclusion, our study shows strong evidence indicating that DNMT1 plays an important role in DEHP-induced exacerbation of psoriasiform inflammation in mice through hypermethylation of DNA.

Structure of human DPPA3 bound to the UHRF1 PHD finger reveals its functional and structural differences from mouse DPPA3

DNA methylation maintenance is essential for cell fate inheritance. In differentiated cells, this involves orchestrated actions of DNMT1 and UHRF1. In mice, the high-affinity binding of DPPA3 to the UHRF1 PHD finger regulates UHRF1 chromatin dissociation and cytosolic localization, which is required for oocyte maturation and early embryo development. However, the human DPPA3 ortholog functions during these stages remain unclear. Here, we report the structural basis for human DPPA3 binding to the UHRF1 PHD finger. The conserved human DPPA3 85VRT87 motif binds to the acidic surface of UHRF1 PHD finger, whereas mouse DPPA3 binding additionally utilizes two unique α-helices. The binding affinity of human DPPA3 for the UHRF1 PHD finger was weaker than that of mouse DPPA3. Consequently, human DPPA3, unlike mouse DPPA3, failed to inhibit UHRF1 chromatin binding and DNA remethylation in Xenopus egg extracts effectively. Our data provide novel insights into the distinct function and structure of human DPPA3.

Survival Rate and Chronic Diseases of TCGA Cancer and KoGES Normal Samples by Clustering for DNA Methylation

Insights from public DNA methylation data derived from cancer or normal tissues from cancer patients or healthy people can be obtained by machine learning. The goal is to determine methylation patterns that could be useful for predicting the prognosis for cancer patients and correcting lifestyles for healthy people. DNA methylation data were obtained from the DNA of 446 healthy participants from the Korean Genome Epidemiology Study (KoGES) and from the DNA of normal tissues or from cancer tissues of 11 types of carcinomas from The Cancer Genome Atlas (TCGA) database. To correct for the batch effect, R's ComBat function was used. Using the K-mean clustering (k = 3), the survival rates of the cancer patients and the incidence of chronic diseases were compared between the three clusters for TCGA and KoGES, respectively. Based on the public DNA methylation and clinical data of healthy participants and cancer patients, I present an analysis pipeline that integrates and clusters the methylation data from the two groups. As a result of clustering, CpG sites from gene or genomic regions, such as AFAP1, NINJ2, and HOOK2 genes, that correlated with survival rate and chronic disease are presented.

Integrative analysis of ultra-deep RNA-seq reveals alternative promoter usage as a mechanism of activating oncogenic programmes during prostate cancer progression

Transcription factor (TF) proteins regulate gene activity by binding to regulatory regions, most importantly at gene promoters. Many genes have alternative promoters (APs) bound by distinct TFs. The role of differential TF activity at APs during tumour development is poorly understood. Here we show, using deep RNA sequencing in 274 biopsies of benign prostate tissue, localized prostate tumours and metastatic castration-resistant prostate cancer, that AP usage increases as tumours progress and APs are responsible for a disproportionate amount of tumour transcriptional activity. Expression of the androgen receptor (AR), the key driver of prostate tumour activity, is correlated with elevated AP usage. We identified AR, FOXA1 and MYC as potential drivers of AP activation. DNA methylation is a likely mechanism for AP activation during tumour progression and lineage plasticity. Our data suggest that prostate tumours activate APs to magnify the transcriptional impact of tumour drivers, including AR and MYC.

Periconceptional Non-medical Maternal Determinants Influence the Tryptophan Metabolism: The Rotterdam Periconceptional Cohort (Predict Study)

Background

The vital role of the maternal tryptophan (TRP) metabolism in maternal health and pregnancy is well established. However, non-medical maternal determinants influencing the TRP metabolism have been poorly investigated. We hypothesise that periconceptional maternal non-medical determinants alter the TRP metabolism, affecting both kynurenine (KP) and serotonin pathway (SP) metabolite concentrations. Therefore, we investigated the influence of non-medical maternal determinants on the TRP metabolism during the periconception period.

Methods

About 1916 pregnancies were included from the Rotterdam Periconceptional Cohort between November 2010 and December 2020. Data on periconceptional non-medical maternal determinants were collected through questionnaires. Serum samples were collected at 8.5 (SD = 1.6) weeks of gestation and TRP, kynurenine (KYN), 5-hydroxytryptophan (5-HTP), 5-HT (5-hydroxytryptamine) and 5-hydroxyindole acetic acid (5-HIAA) were determined using validated liquid chromatography (tandem) mass spectrometry. Mixed models were used to determine associations between periconceptional non-medical maternal determinants and these metabolites.

Results

In total 11 periconceptional non-medical maternal determinants were identified. Protein intake was positively associated with TRP (β = .12, 95% CI = 0.07-0.17), while age, energy intake and body mass index (BMI) (β = -.24, 95% CI = -0.37 to -0.10) were negatively associated with TRP. Age, BMI and total homocysteine were associated with higher KYN, whereas non-western geographical origin was associated with lower KYN (β = -.09, 95% CI = -0.16 to -0.03). Protein intake and total homocysteine (β = .07, 95% CI = 0.03-0.11) had a positive association with 5-HTP, while a negative association was found for energy intake. A non-western geographical origin and drug use were associated with higher 5-HT, and BMI with lower 5-HT (β = -6.32, 95% CI = -10.26 to -2.38). Age was positively associated with 5-HIAA (β = .92, 95% CI = 0.29-1.56), and BMI negatively.

Conclusions

Periconceptional non-medical maternal determinants, including age, geographical origin, drug use, energy and protein intake, BMI and total homocysteine, influence KP and SP metabolite concentrations.

Molecular adaptations in response to exercise training are associated with tissue-specific transcriptomic and epigenomic signatures

Regular exercise has many physical and brain health benefits, yet the molecular mechanisms mediating exercise effects across tissues remain poorly understood. Here we analyzed 400 high-quality DNA methylation, ATAC-seq, and RNA-seq datasets from eight tissues from control and endurance exercise-trained (EET) rats. Integration of baseline datasets mapped the gene location dependence of epigenetic control features and identified differing regulatory landscapes in each tissue. The transcriptional responses to 8 weeks of EET showed little overlap across tissues and predominantly comprised tissue-type enriched genes. We identified sex differences in the transcriptomic and epigenomic changes induced by EET. However, the sex-biased gene responses were linked to shared signaling pathways. We found that many G protein-coupled receptor-encoding genes are regulated by EET, suggesting a role for these receptors in mediating the molecular adaptations to training across tissues. Our findings provide new insights into the mechanisms underlying EET-induced health benefits across organs.

Genome-wide DNA methylation changes in human spermatogenesis

Sperm production and function require the correct establishment of DNA methylation patterns in the germline. Here, we examined the genome-wide DNA methylation changes during human spermatogenesis and its alterations in disturbed spermatogenesis. We found that spermatogenesis is associated with remodeling of the methylome, comprising a global decline in DNA methylation in primary spermatocytes followed by selective remethylation, resulting in a spermatids/sperm-specific methylome. Hypomethylated regions in spermatids/sperm were enriched in specific transcription factor binding sites for DMRT and SOX family members and spermatid-specific genes. Intriguingly, while SINEs displayed differential methylation throughout spermatogenesis, LINEs appeared to be protected from changes in DNA methylation. In disturbed spermatogenesis, germ cells exhibited considerable DNA methylation changes, which were significantly enriched at transposable elements and genes involved in spermatogenesis. We detected hypomethylation in SVA and L1HS in disturbed spermatogenesis, suggesting an association between the abnormal programming of these regions and failure of germ cells progressing beyond meiosis.

DNA methylation patterns of transcription factor binding regions characterize their functional and evolutionary contexts

BACKGROUND

DNA methylation is an important epigenetic modification which has numerous roles in modulating genome function. Its levels are spatially correlated across the genome, typically high in repressed regions but low in transcription factor (TF) binding sites and active regulatory regions. However, the mechanisms establishing genome-wide and TF binding site methylation patterns are still unclear.

RESULTS

Here we use a comparative approach to investigate the association of DNA methylation to TF binding evolution in mammals. Specifically, we experimentally profile DNA methylation and combine this with published occupancy profiles of five distinct TFs (CTCF, CEBPA, HNF4A, ONECUT1, FOXA1) in the liver of five mammalian species (human, macaque, mouse, rat, dog). TF binding sites are lowly methylated, but they often also have intermediate methylation levels. Furthermore, biding sites are influenced by the methylation status of CpGs in their wider binding regions even when CpGs are absent from the core binding motif. Employing a classification and clustering approach, we extract distinct and species-conserved patterns of DNA methylation levels at TF binding regions. CEBPA, HNF4A, ONECUT1, and FOXA1 share the same methylation patterns, while CTCF's differ. These patterns characterize alternative functions and chromatin landscapes of TF-bound regions. Leveraging our phylogenetic framework, we find DNA methylation gain upon evolutionary loss of TF occupancy, indicating coordinated evolution. Furthermore, each methylation pattern has its own evolutionary trajectory reflecting its genomic contexts.

CONCLUSIONS

Our epigenomic analyses indicate a role for DNA methylation in TF binding changes across species including that specific DNA methylation profiles characterize TF binding and are associated with their regulatory activity, chromatin contexts, and evolutionary trajectories.

Choline-An Underappreciated Component of a Mother-to-Be's Diet

The nutritional status of the mother-to-be has a key impact on the proper development of the fetus. Although all nutrients are important for the developing baby, recent research indicates the importance of adequate choline intake during the periconceptional period, pregnancy, and lactation. Choline plays a key role in the biosynthesis of cell membranes, supporting liver function, neurotransmission, brain development, and DNA and histone methylation. Choline participates in the formation of a child's nervous system, supports its cognitive development, and reduces the risk of neural tube defects. The human body is incapable of producing sufficient choline to meet its needs; therefore, it must be obtained from the diet. Current data indicate that most women in their reproductive years do not achieve the recommended daily intake of choline. The presented narrative review indicates the importance of educating mothers-to-be and thereby increasing their awareness of the effects of choline on maternal and child health, which can lead to a more aware and healthy pregnancy and proper child development.

Advances in the joint profiling technologies of 5mC and 5hmC

DNA cytosine methylation, a crucial epigenetic modification, involves the dynamic interplay of 5-methylcytosine (5mC) and its oxidized form, 5-hydroxymethylcytosine (5hmC), generated by ten-eleven translocation (TET) DNA dioxygenases. This process is central to regulating gene expression, influencing critical biological processes such as development, disease progression, and aging. Recognizing the distinct functions of 5mC and 5hmC, researchers often employ restriction enzyme-based or chemical treatment methods for their simultaneous measurement from the same genomic sample. This enables a detailed understanding of the relationship between these modifications and their collective impact on cellular function. This review focuses on summarizing the technologies for detecting 5mC and 5hmC together but also discusses the limitations and potential future directions in this evolving field.

Epigenetic modifications in abdominal aortic aneurysms: from basic to clinical

Abdominal Aortic Aneurysm (AAA) is a disease characterized by localized dilation of the abdominal aorta, involving multiple factors in its occurrence and development, ultimately leading to vessel rupture and severe bleeding. AAA has a high mortality rate, and there is a lack of targeted therapeutic drugs. Epigenetic regulation plays a crucial role in AAA, and the treatment of AAA in the epigenetic field may involve a series of related genes and pathways. Abnormal expression of these genes may be a key factor in the occurrence of the disease and could potentially serve as promising therapeutic targets. Understanding the epigenetic regulation of AAA is of significant importance in revealing the mechanisms underlying the disease and identifying new therapeutic targets. This knowledge can contribute to offering AAA patients better clinical treatment options beyond surgery. This review systematically explores various aspects of epigenetic regulation in AAA, including DNA methylation, histone modification, non-coding RNA, and RNA modification. The analysis of the roles of these regulatory mechanisms, along with the identification of relevant genes and pathways associated with AAA, is discussed comprehensively. Additionally, a comprehensive discussion is provided on existing treatment strategies and prospects for epigenetics-based treatments, offering insights for future clinical interventions.

Aptamer-based assembly systems for SARS-CoV-2 detection and therapeutics

Nucleic acid aptamers are oligonucleotide chains with molecular recognition properties. Compared with antibodies, aptamers show advantages given that they are readily produced via chemical synthesis and elicit minimal immunogenicity in biomedicine applications. Notably, aptamer-encoded nucleic acid assemblies further improve the binding affinity of aptamers with the targets due to their multivalent synergistic interactions. Specially, aptamers can be engineered with special topological arrangements in nucleic acid assemblies, which demonstrate spatial and valence matching towards antigens on viruses, thus showing potential in the detection and therapeutic applications of viruses. This review presents the recent progress on the aptamers explored for SARS-CoV-2 detection and infection treatment, wherein applications of aptamer-based assembly systems are introduced in detail. Screening methods and chemical modification strategies for aptamers are comprehensively summarized, and the types of aptamers employed against different target domains of SARS-CoV-2 are illustrated. The evolution of aptamer-based assembly systems for the detection and neutralization of SARS-CoV-2, as well as the construction principle and characteristics of aptamer-based DNA assemblies are demonstrated. The typically representative works are presented to demonstrate how to assemble aptamers rationally and elaborately for specific applications in SARS-CoV-2 diagnosis and neutralization. Finally, we provide deep insights into the current challenges and future perspectives towards aptamer-based nucleic acid assemblies for virus detection and neutralization in nanomedicine.

A Molecular Voyage: Multiomics Insights into Circulating Tumor Cells

Circulating tumor cells (CTCs) play a pivotal role in metastasis, the leading cause of cancer-associated death. Recent improvements of CTC isolation tools, coupled with a steady development of multiomics technologies at single-cell resolution, have enabled an extensive exploration of CTC biology, unlocking insights into their molecular profiles. A detailed molecular portrait requires CTC interrogation across various levels encompassing genomic, epigenetic, transcriptomic, proteomic and metabolic features. Here, we review how state-of-the-art multiomics applied to CTCs are shedding light on how cancer spreads. Further, we highlight the potential implications of CTC profiling for clinical applications aimed at enhancing cancer diagnosis and treatment.

SIGNIFICANCE

Exploring the complexity of cancer progression through cutting-edge multiomics studies holds the promise of uncovering novel aspects of cancer biology and identifying therapeutic vulnerabilities to suppress metastasis.

Extraembryonic gut endoderm cells undergo programmed cell death during development

Despite a distinct developmental origin, extraembryonic cells in mice contribute to gut endoderm and converge to transcriptionally resemble their embryonic counterparts. Notably, all extraembryonic progenitors share a non-canonical epigenome, raising several pertinent questions, including whether this landscape is reset to match the embryonic regulation and if extraembryonic cells persist into later development. Here we developed a two-colour lineage-tracing strategy to track and isolate extraembryonic cells over time. We find that extraembryonic gut cells display substantial memory of their developmental origin including retention of the original DNA methylation landscape and resulting transcriptional signatures. Furthermore, we show that extraembryonic gut cells undergo programmed cell death and neighbouring embryonic cells clear their remnants via non-professional phagocytosis. By midgestation, we no longer detect extraembryonic cells in the wild-type gut, whereas they persist and differentiate further in p53-mutant embryos. Our study provides key insights into the molecular and developmental fate of extraembryonic cells inside the embryo.

Identification of the DNA methylation signature of Mowat-Wilson syndrome

Mowat-Wilson syndrome (MOWS) is a rare congenital disease caused by haploinsufficiency of ZEB2, encoding a transcription factor required for neurodevelopment. MOWS is characterized by intellectual disability, epilepsy, typical facial phenotype and other anomalies, such as short stature, Hirschsprung disease, brain and heart defects. Despite some recognizable features, MOWS rarity and phenotypic variability may complicate its diagnosis, particularly in the neonatal period. In order to define a novel diagnostic biomarker for MOWS, we determined the genome-wide DNA methylation profile of DNA samples from 29 individuals with confirmed clinical and molecular diagnosis. Through multidimensional scaling and hierarchical clustering analysis, we identified and validated a DNA methylation signature involving 296 differentially methylated probes as part of the broader MOWS DNA methylation profile. The prevalence of hypomethylated CpG sites agrees with the main role of ZEB2 as a transcriptional repressor, while differential methylation within the ZEB2 locus supports the previously proposed autoregulation ability. Correlation studies compared the MOWS cohort with 56 previously described DNA methylation profiles of other neurodevelopmental disorders, further validating the specificity of this biomarker. In conclusion, MOWS DNA methylation signature is highly sensitive and reproducible, providing a useful tool to facilitate diagnosis.

Interconnected Codons: Unravelling the Epigenetic Significance of Flanking Sequences in CpG Dyads

Hypothesizing that CpG codon dyads, formed by consecutive codons containing a cytosine-guanine pair (NNC-GNN), may play a crucial role in gene function, we conducted an extensive analysis to investigate their distribution and conservation within mammalian genes. Our findings reveal that genes characterized by a high density of CpG codon dyads are notably associated with homeobox domains and RNA polymerase II transcription factors. Conversely, genes exhibiting low CpG codon dyad density have links to DNA damage repair and mitosis. Importantly, our study identifies a re-markable increase in expressed genes that harbor CpG during embryonic development, suggesting their potential involvement in gene regulation at these developmental stages. These results under-score the functional significance of CpG codon dyads in DNA methylation and gene expression, fur-ther demonstrating the coevolution of consecutive codons and their contribution to codon usage bias.

Neural-net-based cell deconvolution from DNA methylation reveals tumor microenvironment associated with cancer prognosis

DNA methylation is a pivotal epigenetic modification that defines cellular identity. While cell deconvolution utilizing this information is considered useful for clinical practice, current methods for deconvolution are limited in their accuracy and resolution. In this study, we collected DNA methylation data from 945 human samples derived from various tissues and tumor-infiltrating immune cells and trained a neural network model with them. The model, termed MEnet, predicted abundance of cell population together with the detailed immune cell status from bulk DNA methylation data, and showed consistency to those of flow cytometry and histochemistry. MEnet was superior to the existing methods in the accuracy, speed, and detectable cell diversity, and could be applicable for peripheral blood, tumors, cell-free DNA, and formalin-fixed paraffin-embedded sections. Furthermore, by applying MEnet to 72 intrahepatic cholangiocarcinoma samples, we identified immune cell profiles associated with cancer prognosis. We believe that cell deconvolution by MEnet has the potential for use in clinical settings.

Therapeutic targeting of DNA methylation alterations in cancer

DNA methylation is a critical component of gene regulation and plays an important role in the development of cancer. Hypermethylation of tumor suppressor genes and silencing of DNA repair pathways facilitate uncontrolled cell growth and synergize with oncogenic mutations to perpetuate cancer phenotypes. Additionally, aberrant DNA methylation hinders immune responses crucial for antitumor immunity. Thus, inhibiting dysregulated DNA methylation is a promising cancer therapy. Pharmacologic inhibition of DNA methylation reactivates silenced tumor suppressors and bolster immune responses through induction of viral mimicry. Now, with the advent of immunotherapies and discovery of the immune-modulatory effects of DNA methylation inhibitors, there is great interest in understanding how targeting DNA methylation in combination with other therapies can enhance antitumor immunity. Here, we describe the role of aberrant DNA methylation in cancer and mechanisms by which it promotes tumorigenesis and modulates immune responses. Finally, we review the initial discoveries and ongoing efforts to target DNA methylation as a cancer therapeutic.

Decreased Treg cells induced by bisphenol A is associated with up-regulation of PI3K/Akt/mTOR signaling pathway and Foxp3 DNA methylation in spleen of adolescent mice

The current study aimed to explore whether bisphenol A (BPA) exposure aggravated the decrease in Tregs induced by ovalbumin (OVA) in adolescent female mouse models of asthma, and whether the process was associated with mTOR-mediated signaling pathways and DNA methylation levels. A total of 40 female C57BL/6 mice at the age of four weeks were used and divided into five groups after 1 week of domestication. Each group consisted of eight mice: the control group, OVA group, OVA + BPA (0.1 μg mL-1) group, OVA + BPA (0.2 μg mL-1) group, and OVA + BPA (0.4 μg mL-1) group. Results revealed that Foxp3 protein levels decreased in the spleens of mice exposed to BPA compared to those in the OVA group. After an elevation in BPA dose, the mRNAs of methyltransferases (Dnmt1, Dnmt3a, and Dnmt3b) were gradually upregulated. The mechanism was related to the activity of TLR4/NF-κB and PI3K/Akt/mTOR signaling pathways and the enhancement of Foxp3 DNA methylation. Our results, collectively, provided a new view for studying the mechanisms underlying BPA exposure-induced immune dysfunction. Investigation of the regulatory mechanisms of DNA methylation in the abnormal Th immune response caused by BPA exposure could help reveal the causes and molecular mechanisms underlying the high incidence of allergic diseases in children in recent years.

Ovarian aging: energy metabolism of oocytes

In women who are getting older, the quantity and quality of their follicles or oocytes and decline. This is characterized by decreased ovarian reserve function (DOR), fewer remaining oocytes, and lower quality oocytes. As more women choose to delay childbirth, the decline in fertility associated with age has become a significant concern for modern women. The decline in oocyte quality is a key indicator of ovarian aging. Many studies suggest that age-related changes in oocyte energy metabolism may impact oocyte quality. Changes in oocyte energy metabolism affect adenosine 5'-triphosphate (ATP) production, but how related products and proteins influence oocyte quality remains largely unknown. This review focuses on oocyte metabolism in age-related ovarian aging and its potential impact on oocyte quality, as well as therapeutic strategies that may partially influence oocyte metabolism. This research aims to enhance our understanding of age-related changes in oocyte energy metabolism, and the identification of biomarkers and treatment methods.

Epigenetic Insights Into Necrotizing Enterocolitis: Unraveling Methylation-Regulated Biomarkers

Necrotizing enterocolitis (NEC) is a multifactorial gastrointestinal disease with high morbidity and mortality among premature infants. This study aimed to identify novel methylation-regulated biomarkers in NEC intestinal tissue through multiomics analysis. We analyzed DNA methylation and transcriptome datasets from ileum and colon tissues of patients with NEC. We identify methylation-related differential genes (MrDEGs) based on the rule that the degree of methylation in the promoter region is inversely proportional to RNA transcription. These MrDEGs included ADAP1, GUCA2A, BCL2L14, FUT3, MISP, USH1C, ITGA3, UNC93A and IL22RA1. Single-cell data revealed that MrDEGs were mainly located in the intestinal epithelial part of intestinal tissue. These MrDEGs were verified through Target gene bisulfite sequencing and RT-qPCR. We successfully identified and verified the ADAP1, GUCA2A, IL22RA1 and MISP, primarily expressed in intestinal epithelial villus cells through single-cell data. Through single-gene gene set enrichment analysis, we found that these genes participate mainly in the pathological process of T-cell differentiation and the suppression of intestinal inflammation in NEC. This study enhances our understanding of the pathogenesis of NEC and may promote the development of new precision medicine methods for NEC prediction and diagnosis.

The Latent Aging of Cells

As epigenetic clocks have evolved from powerful estimators of chronological aging to predictors of mortality and disease risk, it begs the question of what role DNA methylation plays in the aging process. We hypothesize that while it has the potential to serve as an informative biomarker, DNA methylation could also be a key to understanding the biology entangled between aging, (de)differentiation, and epigenetic reprogramming. Here we use an unsupervised approach to analyze time associated DNA methylation from both in vivo and in vitro samples to measure an underlying signal that ties these phenomena together. We identify a methylation pattern shared across all three, as well as a signal that tracks aging in tissues but appears refractory to reprogramming, suggesting that aging and reprogramming may not be fully mirrored processes.

Correlation-based network integration of lung RNA sequencing and DNA methylation data in chronic obstructive pulmonary disease

Chronic Obstructive Pulmonary Disease (COPD) is a heterogeneous, chronic inflammatory process of the lungs and, like other complex diseases, is caused by both genetic and environmental factors. Detailed understanding of the molecular mechanisms of complex diseases requires the study of the interplay among different biomolecular layers, and thus the integration of different omics data types. In this study, we investigated COPD-associated molecular mechanisms through a correlation-based network integration of lung tissue RNA-seq and DNA methylation data of COPD cases (n = 446) and controls (n = 346) derived from the Lung Tissue Research Consortium. First, we performed a SWIM-network based analysis to build separate correlation networks for RNA-seq and DNA methylation data for our case-control study population. Then, we developed a method to integrate the results into a coupled network of differentially expressed and differentially methylated genes to investigate their relationships across both molecular layers. The functional enrichment analysis of the nodes of the coupled network revealed a strikingly significant enrichment in Immune System components, both innate and adaptive, as well as immune-system component communication (interleukin and cytokine-cytokine signaling). Our analysis allowed us to reveal novel putative COPD-associated genes and to analyze their relationships, both at the transcriptomics and epigenomics levels, thus contributing to an improved understanding of COPD pathogenesis.

Loci cg06256735 and cg15815843 in the MFAP5 gene regulatory regions are hypomethylated in varicose veins apparently due to active demethylation

Varicose vein disease (VVD) is a common health problem worldwide. Microfibril-associated protein 5 (MFAP5) is one of the potential key players in its pathogenesis. Our previous microarray analysis revealed the cg06256735 and cg15815843 loci in the regulatory regions of the MFAP5 gene as hypomethylated in varicose veins which correlated with its up-regulation. The aim of this work was to validate preliminary microarray data, estimate the level of 5-hydroxymethylcytosine (5hmC) at these loci, and determine the methylation status of one of them in different layers of the venous wall. For this, methyl- and hydroxymethyl-sensitive restriction techniques were used followed by real-time PCR and droplet digital PCR, correspondingly, as well as bisulfite pyrosequencing of +/- oxidized DNA. Our microarray data on hypomethylation at the cg06256735 and cg15815843 loci in whole varicose vein segments were confirmed and it was also demonstrated that the level of 5hmC at these loci is increased in VVD. Specifically, among other layers of the venous wall, tunica (t.) intima is the main contributor to hypomethylation at the cg06256735 locus in varicose veins. Thus, it was shown that hypomethylation at the cg06256735 and cg15815843 loci takes place in VVD, with evidence to suggest that it happens through their active demethylation leading to up-regulation of the MFAP5 gene, and t. intima is most involved in this biochemical process.

Cotton transposon-related variome reveals roles of transposon-related variations in modern cotton cultivation

INTRODUCTION

Transposon plays a vital role in cotton genome evolution, contributing to the expansion and divergence of genomes within the Gossypium genus. However, knowledge of transposon activity in modern cotton cultivation is limited.

OBJECTIVES

In this study, we aimed to construct transposon-related variome within Gossypium genus and reveal role of transposon-related variations during cotton cultivation. In addition, we try to identify valuable transposon-related variations for cotton breeding.

METHODS

We utilized graphical genome construction to build up the graphical transposon-related variome. Based on the graphical variome, we integrated t-test, eQTL analysis and Mendelian Randomization (MR) to identify valuable transposon activities and elite genes. In addition, a convolutional neural network (CNN) model was constructed to evaluate epigenomic effects of transposon-related variations.

RESULTS

We identified 35,980 transposon activities among 10 cotton genomes, and the diversity of genomic and epigenomic features was observed among 21 transposon categories. The graphical cotton transposon-related variome was constructed, and 9,614 transposon-related variations with plasticity in the modern cotton cohort were used for eQTL, phenotypic t-test and Mendelian Randomization. 128 genes were identified as gene resources improving fiber length and strength simultaneously. 4 genes were selected from 128 genes to construct the elite gene panel whose utility has been validated in a natural cotton cohort and 2 accessions with phenotypic divergence. Based on the eQTL analysis results, we identified transposon-related variations involved in cotton's environmental adaption and human domestication, providing evidence of their role in cotton's adaption-domestication cooperation.

CONCLUSIONS

The cotton transposon-related variome revealed the role of transposon-related variations in modern cotton cultivation, providing genomic resources for cotton molecular breeding.

Improve-RRBS: a novel tool to correct the 3' trimming of reduced representation sequencing reads

Motivation

Reduced Representation Bisulfite Sequencing (RRBS) is a popular approach to determine DNA methylation of the CpG-rich regions of the genome. However, we observed that false positive differentially methylated sites (DMS) are also identified using the standard computational analysis.

Results

During RRBS library preparation the MspI digested DNA undergo end-repair by a cytosine at the 3' end of the fragments. After sequencing, Trim Galore cuts these end-repaired nucleotides. However, Trim Galore fails to detect end-repair when it overlaps with the 3' end of the sequencing reads. We found that these non-trimmed cytosines bias methylation calling, thus, can identify DMS erroneously. To circumvent this problem, we developed improve-RRBS, which efficiently identifies and hides these cytosines from methylation calling with a false positive rate of maximum 0.5%. To test improve-RRBS, we investigated four datasets from four laboratories and two different species. We found non-trimmed 3' cytosines in all datasets analyzed and as much as >50% of false positive DMS under certain conditions. By applying improve-RRBS, these DMS completely disappeared from all comparisons.

Availability and implementation

Improve-RRBS is a freely available python package https://pypi.org/project/iRRBS/ or https://github.com/fothia/improve-RRBS to be implemented in RRBS pipelines.

Altered Genome-Wide DNA Methylation in the Duodenum of Common Variable Immunodeficiency Patients

PURPOSE

A large proportion of Common variable immunodeficiency (CVID) patients has duodenal inflammation with increased intraepithelial lymphocytes (IEL) of unknown aetiology. The histologic similarities to celiac disease, lead to confusion regarding treatment (gluten-free diet) of these patients. We aimed to elucidate the role of epigenetic DNA methylation in the aetiology of duodenal inflammation in CVID and differentiate it from true celiac disease.

METHODS

DNA was isolated from snap-frozen pieces of duodenal biopsies and analysed for differences in genome-wide epigenetic DNA methylation between CVID patients with increased IEL (CVID_IEL; n = 5) without IEL (CVID_N; n = 3), celiac disease (n = 3) and healthy controls (n = 3).

RESULTS

The DNA methylation data of 5-methylcytosine in CpG sites separated CVID and celiac diseases from healthy controls. Differential methylation in promoters of genes were identified as potential novel mediators in CVID and celiac disease. There was limited overlap of methylation associated genes between CVID_IEL and Celiac disease. High frequency of differentially methylated CpG sites was detected in over 100 genes nearby transcription start site (TSS) in both CVID_IEL and celiac disease, compared to healthy controls. Differential methylation of genes involved in regulation of TNF/cytokine production were enriched in CVID_IEL, compared to healthy controls.

CONCLUSION

This is the first study to reveal a role of epigenetic DNA methylation in the etiology of duodenal inflammation of CVID patients, distinguishing CVID_IEL from celiac disease. We identified potential biomarkers and therapeutic targets within gene promotors and in high-frequency differentially methylated CpG regions proximal to TSS in both CVID_IEL and celiac disease.

Epigenetic mechanisms linking early-life adversities and mental health

Early-life adversities, whether prenatal or postnatal exposure, have been linked to adverse mental health outcomes later in life increasing the risk of several psychiatric disorders. Research on its neurobiological consequences demonstrated an association between exposure to adversities and persistent alterations in the structure, function, and connectivity of the brain. Consistent evidence supports the idea that regulation of gene expression through epigenetic mechanisms are involved in embedding the impact of early-life experiences in the genome and mediate between social environments and later behavioral phenotypes. In addition, studies from rodent models and humans suggest that these experiences and the acquired risk factors can be transmitted through epigenetic mechanisms to offspring and the following generations potentially contributing to a cycle of disease or disease risk. However, one of the important aspects of epigenetic mechanisms, unlike genetic sequences that are fixed and unchangeable, is that although the epigenetic markings are long-lasting, they are nevertheless potentially reversible. In this review, we summarize our current understanding of the epigenetic mechanisms involved in the mental health consequences derived from early-life exposure to malnutrition, maltreatment and poverty, adversities with huge and pervasive impact on mental health. We also discuss the evidence about transgenerational epigenetic inheritance in mammals and experimental data suggesting that suitable social and pharmacological interventions could reverse adverse epigenetic modifications induced by early-life negative social experiences. In this regard, these studies must be accompanied by efforts to determine the causes that promote these adversities and that result in health inequity in the population.

Investigating neonatal health risk variables through cell-type specific methylome-wide association studies

Adverse neonatal outcomes are a prevailing risk factor for both short- and long-term mortality and morbidity in infants. Given the importance of these outcomes, refining their assessment is paramount for improving prevention and care. Here we aim to enhance the assessment of these often correlated and multifaceted neonatal outcomes. To achieve this, we employ factor analysis to identify common and unique effects and further confirm these effects using criterion-related validity testing. This validation leverages methylome-wide profiles from neonatal blood. Specifically, we investigate nine neonatal health risk variables, including gestational age, Apgar score, three indicators of body size, jaundice, birth diagnosis, maternal preeclampsia, and maternal age. The methylomic profiles used for this research capture data from nearly all 28 million methylation sites in human blood, derived from the blood spot collected from 333 neonates, within 72 h post-birth. Our factor analysis revealed two common factors, size factor, that captured the shared effects of weight, head size, height, and gestational age and disease factor capturing the orthogonal shared effects of gestational age, combined with jaundice and birth diagnosis. To minimize false positives in the validation studies, validation was limited to variables with significant cumulative association as estimated through an in-sample replication procedure. This screening resulted in that the two common factors and the unique effects for gestational age, jaundice and Apgar were further investigated with full-scale cell-type specific methylome-wide association analyses. Highly significant, cell-type specific, associations were detected for both common effect factors and for Apgar. Gene Ontology analyses revealed multiple significant biologically relevant terms for the five fully investigated neonatal health risk variables. Given the established links between adverse neonatal outcomes and both immediate and long-term health, the distinct factor effects (representing the common and unique effects of the risk variables) and their biological profiles confirmed in our work, suggest their potential role as clinical biomarkers for assessing health risks and enhancing personalized care.

Integrated analysis of blood DNA methylation, genetic variants, circulating proteins, microRNAs, and kidney failure in type 1 diabetes

Variation in DNA methylation (DNAmet) in white blood cells and other cells/tissues has been implicated in the etiology of progressive diabetic kidney disease (DKD). However, the specific mechanisms linking DNAmet variation in blood cells with risk of kidney failure (KF) and utility of measuring blood cell DNAmet in personalized medicine are not clear. We measured blood cell DNAmet in 277 individuals with type 1 diabetes and DKD using Illumina EPIC arrays; 51% of the cohort developed KF during 7 to 20 years of follow-up. Our epigenome-wide analysis identified DNAmet at 17 CpGs (5'-cytosine-phosphate-guanine-3' loci) associated with risk of KF independent of major clinical risk factors. DNAmet at these KF-associated CpGs remained stable over a median period of 4.7 years. Furthermore, DNAmet variations at seven KF-associated CpGs were strongly associated with multiple genetic variants at seven genomic regions, suggesting a strong genetic influence on DNAmet. The effects of DNAmet variations at the KF-associated CpGs on risk of KF were partially mediated by multiple KF-associated circulating proteins and KF-associated circulating miRNAs. A prediction model for risk of KF was developed by adding blood cell DNAmet at eight selected KF-associated CpGs to the clinical model. This updated model significantly improved prediction performance (c-statistic = 0.93) versus the clinical model (c-statistic = 0.85) at P = 6.62 × 10-14. In conclusion, our multiomics study provides insights into mechanisms through which variation of DNAmet may affect KF development and shows that blood cell DNAmet at certain CpGs can improve risk prediction for KF in T1D.

MSA: scalable DNA methylation screening BeadChip for high-throughput trait association studies

The Infinium DNA Methylation BeadChips have significantly contributed to population-scale epigenetics research by enabling epigenome-wide trait association discoveries. Here, we design, describe, and experimentally verify a new iteration of this technology, the Methylation Screening Array (MSA), to focus on human trait screening and discovery. This array utilizes extensive data from previous Infinium platform-based epigenome-wide association studies (EWAS). It incorporates knowledge from the latest single-cell and cell type-resolution whole genome methylome profiles. The MSA is engineered to achieve scalable screening of epigenetics-trait association in an ultra-high sample throughput. Our design encompassed diverse human trait associations, including those with genetic, cellular, environmental, and demographical variables and human diseases such as genetic, neurodegenerative, cardiovascular, infectious, and immune diseases. We comprehensively evaluated this array's reproducibility, accuracy, and capacity for cell-type deconvolution and supporting 5-hydroxymethylation profiling in diverse human tissues. Our first atlas data using this platform uncovered the complex chromatin and tissue contexts of DNA modification variations and genetic variants linked to human phenotypes.

Unveiling dissociation mechanisms and binding patterns in the UHRF1-DPPA3 complex via multi-replica molecular dynamics simulations

CONTEXT

Ubiquitin-like with PHD and RING finger domain containing protein 1 (UHRF1) is responsible for preserving the stability of genomic methylation through the recruitment of DNA methyltransferase 1 (DNMT1). However, the interaction between Developmental pluripotency associated 3 (DPPA3) and the pre-PHD-PHD (PPHD) domain of UHRF1 hinders the nuclear localization of UHRF1. This disruption has implications for potential cancer treatment strategies. Drugs that mimic the binding pattern between DPPA3 and PPHD could offer a promising approach to cancer treatment. Our study reveals that DPPA3 undergoes dissociation from the C-terminal through three different modes of helix unfolding. Furthermore, we have identified key residue pairs involved in this dissociation process and potential drug-targeting residues. These findings offer valuable insights into the dissociation mechanism of DPPA3 from PPHD and have the potential to inform the design of novel drugs targeting UHRF1 for cancer therapy.

METHODS

To comprehend the dissociation process and binding patterns of PPHD-DPPA3, we employed enhanced sampling techniques, including steered molecular dynamics (SMD) and conventional molecular dynamics (cMD). Additionally, we utilized self-organizing maps (SOM) and time-resolved force distribution analysis (TRFDA) methodologies. The Gromacs software was used for performing molecular dynamics simulations, and the AMBER FF14SB force field was applied to the protein.

Anticyanobacterial effect of p-coumaric acid on Limnothrix sp. determined by proteomic and metabolomic analysis

Regulating photosynthetic machinery is a powerful but challenging strategy for selectively inhibiting bloom-forming cyanobacteria, in which photosynthesis mainly occurs in thylakoids. P-coumaric acid (p-CA) has several biological properties, including free radical scavenging and antibacterial effects, and studies have shown that it can damage bacterial cell membranes, reduce chlorophyll a in cyanobacteria, and effectively inhibit algal growth at concentrations exceeding 0.127 g/L. Allelochemicals typically inhibit cyanobacteria by inhibiting photosynthesis; however, research on inhibiting harmful algae using phenolic acids has focused mainly on their inhibitory and toxic effects and metabolite levels, and the molecular mechanism by which p-CA inhibits photosynthesis remains unclear. Thus, we examined the effect of p-CA on the photosynthesis of Limnothrix sp. in detail. We found that p-CA inhibits algal growth and damages photosynthesis-related proteins in Limnothrix sp., reduces carotenoid and allophycocyanin levels, and diminishes the actual quantum yield of Photosystem II (PSII). Moreover, p-CA significantly altered algal cell membrane protein systems, and PSII loss resulting from p-CA exposure promoted reactive oxygen species production. It significantly altered algae cell membrane protein systems. Finally, p-CA was found to be environmentally nontoxic; 80 % of 48-h-old Daphnia magna larvae survived when exposed to 0.15 g/L p-CA. These findings provide insight into the mechanism of cyanobacterial inhibition by p-CA, providing a more practical approach to controlling harmful algal blooms.

Specific DNMT3C flanking sequence preferences facilitate methylation of young murine retrotransposons

The DNA methyltransferase DNMT3C appeared as a duplication of the DNMT3B gene in muroids and is required for silencing of young retrotransposons in the male germline. Using specialized assay systems, we investigate the flanking sequence preferences of DNMT3C and observe characteristic preferences for cytosine at the -2 and -1 flank that are unique among DNMT3 enzymes. We identify two amino acids in the catalytic domain of DNMT3C (C543 and V547) that are responsible for the DNMT3C-specific flanking sequence preferences and evolutionary conserved in muroids. Reanalysis of published data shows that DNMT3C flanking preferences are consistent with genome-wide methylation patterns in mouse ES cells only expressing DNMT3C. Strikingly, we show that CpG sites with the preferred flanking sequences of DNMT3C are enriched in murine retrotransposons that were previously identified as DNMT3C targets. Finally, we demonstrate experimentally that DNMT3C has elevated methylation activity on substrates derived from these biological targets. Our data show that DNMT3C flanking sequence preferences match the sequences of young murine retrotransposons which facilitates their methylation. By this, our data provide mechanistic insights into the molecular co-evolution of repeat elements and (epi)genetic defense systems dedicated to maintain genomic stability in mammals.

Chemical and Enzyme-Mediated Chemical Reactions for Studying Nucleic Acids and Their Modifications

Nucleic acids are genetic information-carrying molecules inside cells. Apart from basic nucleotide building blocks, there exist various naturally occurring chemical modifications on nucleobase and ribose moieties, which greatly increase the encoding complexity of nuclei acids, contribute to the alteration of nucleic acid structures, and play versatile regulation roles in gene expression. To study the functions of certain nucleic acids in various biological contexts, robust tools to specifically label and identify these macromolecules and their modifications, and to illuminate their structures are highly necessary. In this review, we summarize recent technique advances of using chemical and enzyme-mediated chemical reactions to study nucleic acids and their modifications and structures. By highlighting the chemical principles of these techniques, we aim to present a perspective on the advancement of the field as well as to offer insights into developing specific chemical reactions and precise enzyme catalysis utilized for nucleic acids and their modifications.

Mitochondrial defects in sporadic inclusion body myositis-causes and consequences

Sporadic inclusion body myositis (sIBM) is a distinct subcategory of Idiopathic Inflammatory Myopathies (IIM), characterized by unique pathological features such as muscle inflammation, rimmed vacuoles, and protein aggregation within the myofibers. Although hyperactivation of the immune system is widely believed as the primary cause of IIM, it is debated whether non-immune tissue dysfunction might contribute to the disease's onset as patients with sIBM are refractory to conventional immunosuppressant treatment. Moreover, the findings that mitochondrial dysfunction can elicit non-apoptotic programmed cell death and the subsequent immune response further support this hypothesis. Notably, abnormal mitochondrial structure and activities are more prominent in the muscle of sIBM than in other types of IIM, suggesting the presence of defective mitochondria might represent an overlooked contributor to the disease onset. The large-scale mitochondrial DNA deletion, aberrant protein aggregation, and slowed organelle turnover have provided mechanistic insights into the genesis of impaired mitochondria in sIBM. This article reviews the disease hallmarks of sIBM, the plausible contributors of mitochondrial damage in the sIBM muscle, and the immunological responses associated with mitochondrial perturbations. Additionally, the potential application of mitochondrial-targeted chemicals as a new treatment strategy to sIBM is explored and discussed.

Alterations in Skeletal Muscle Insulin Signaling DNA Methylation: A Pilot Randomized Controlled Trial of Olanzapine in Healthy Volunteers

Antipsychotics are associated with severe metabolic side effects including insulin resistance; however, the mechanisms underlying this side effect are not fully understood. The skeletal muscle plays a critical role in insulin-stimulated glucose uptake, and changes in skeletal muscle DNA methylation by antipsychotics may play a role in the development of insulin resistance. A double-blind, placebo-controlled trial of olanzapine was performed in healthy volunteers. Twelve healthy volunteers were randomized to receive 10 mg/day of olanzapine for 7 days. Participants underwent skeletal muscle biopsies to analyze DNA methylation changes using a candidate gene approach for the insulin signaling pathway. Ninety-seven methylation sites were statistically significant (false discovery rate < 0.05 and beta difference between the groups of ≥10%). Fifty-five sites had increased methylation in the skeletal muscle of olanzapine-treated participants while 42 were decreased. The largest methylation change occurred at a site in the Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-Alpha (PPARGC1A) gene, which had 52% lower methylation in the olanzapine group. Antipsychotic treatment in healthy volunteers causes significant changes in skeletal muscle DNA methylation in the insulin signaling pathway. Future work will need to expand on these findings with expression analyses.