Epigenetic Histone Modifications Research Articles

Histone acylation at a glance.

An important mechanism of gene expression regulation is the epigenetic modification of histones. The cofactors and substrates for these modifications are often intermediary metabolites, and it is becoming increasingly clear that the metabolic and nutritional state of cells can influence these marks. These connections between the balance of metabolites, histone modifications and downstream transcriptional changes comprise a metabolic signaling program that can enable cells to adapt to changes in nutrient availability. Beyond acetylation, there is evidence now that histones can be modified by other acyl groups. In this Cell Science at a Glance article and the accompanying poster, we focus on these histone acylation modifications and provide an overview of the players that govern these acylations and their connections with metabolism.

VRK1 Regulates Sensitivity to Oxidative Stress by Altering Histone Epigenetic Modifications and the Nuclear Phosphoproteome in Tumor Cells.

The chromatin organization and its dynamic remodeling determine its accessibility and sensitivity to DNA damage oxidative stress, the main source of endogenous DNA damage. We studied the role of the VRK1 chromatin kinase in the response to oxidative stress. which alters the nuclear pattern of histone epigenetic modifications and phosphoproteome pathways. The early effect of oxidative stress on chromatin was studied by determining the levels of 8-oxoG lesions and the alteration of the epigenetic modification of histones. Oxidative stress caused an accumulation of 8-oxoG DNA lesions that were increased by VRK1 depletion, causing a significant accumulation of DNA strand breaks detected by labeling free 3'-DNA ends. In addition, oxidative stress altered the pattern of chromatin epigenetic marks and the nuclear phosphoproteome pathways that were impaired by VRK1 depletion. Oxidative stress induced the acetylation of H4K16ac and H3K9 and the loss of H3K4me3. The depletion of VRK1 altered all these modifications induced by oxidative stress and resulted in losses of H4K16ac and H3K9ac and increases in the H3K9me3 and H3K4me3 levels. All these changes were induced by the oxidative stress in the epigenetic pattern of histones and impaired by VRK1 depletion, indicating that VRK1 plays a major role in the functional reorganization of chromatin in the response to oxidative stress. The analysis of the nuclear phosphoproteome in response to oxidative stress detected an enrichment of the phosphorylated proteins associated with the chromosome organization and chromatin remodeling pathways, which were significantly decreased by VRK1 depletion. VRK1 depletion alters the histone epigenetic pattern and nuclear phosphoproteome pathways in response to oxidative stress. The enzymes performing post-translational epigenetic modifications are potential targets in synthetic lethality strategies for cancer therapies.

Histone proteoform analysis reveals epigenetic changes in adult mouse brown adipose tissue in response to cold stress

BackgroundRegulation of the thermogenic response by brown adipose tissue (BAT) is an important component of energy homeostasis with implications for the treatment of obesity and diabetes. Our preliminary analyses of RNA-Seq data uncovered many nodes representing epigenetic modifiers that are altered in BAT in response to chronic thermogenic activation. Thus, we hypothesized that chronic thermogenic activation broadly alters epigenetic modifications of DNA and histones in BAT.ResultsMotivated to understand how BAT function is regulated epigenetically, we developed a novel method for the first-ever unbiased top-down proteomic quantitation of histone modifications in BAT and validated our results with a multi-omic approach. To test our hypothesis, wildtype male C57BL/6J mice were housed under chronic conditions of thermoneutral temperature (TN, 28°C), mild cold/room temperature (RT, 22°C), or severe cold (SC, 8°C) and BAT was analyzed for DNA methylation and histone modifications. Methylation of promoters and intragenic regions in genomic DNA decrease in response to chronic cold exposure. Integration of DNA methylation and RNA expression datasets suggest a role for epigenetic modification of DNA in regulation of gene expression in response to cold. In response to cold housing, we observe increased bulk acetylation of histones H3.2 and H4, increased histone H3.2 proteoforms with di- and trimethylation of lysine 9 (K9me2 and K9me3), and increased histone H4 proteoforms with acetylation of lysine 16 (K16ac) in BAT.ConclusionsOur results reveal global epigenetically-regulated transcriptional “on” and “off” signals in murine BAT in response to varying degrees of chronic cold stimuli and establish a novel methodology to quantitatively study histones in BAT, allowing for direct comparisons to decipher mechanistic changes during the thermogenic response. Additionally, we make histone PTM and proteoform quantitation, RNA splicing, RRBS, and transcriptional footprint datasets available as a resource for future research.

A critical role for Pol II CTD phosphorylation in heterochromatic gene activation

How gene activation works in heterochromatin, and how the mechanism might differ from the one used in euchromatin, has been largely unexplored. Previous work has shown that in SIR-regulated heterochromatin of Saccharomyces cerevisiae, gene activation occurs in the absence of covalent histone modifications and other alterations of chromatin commonly associated with transcription.Here we demonstrate that such activation occurs in a substantial fraction of cells, consistent with frequent transcriptional bursting, and this raises the possibility that an alternative activation pathway might be used. We address one such possibility, Pol II CTD phosphorylation, and explore this idea using a natural telomere-linked gene, YFR057w, as a model. Unlike covalent histone modifications, we find that Ser2, Ser5 and Ser7 CTD phosphorylated Pol II is prevalent at the drug-induced heterochromatic gene. Particularly enriched relative to the euchromatic state is Ser2 phosphorylation. Consistent with a functional role for Ser2P, YFR057w is negligibly activated in cells deficient in the Ser2 CTD kinases Ctk1 and Bur1 even though the gene is strongly stimulated when it is placed in a euchromatic context. Collectively, our results are consistent with a critical role for Ser2 CTD phosphorylation in driving Pol II recruitment and transcription of a natural heterochromatic gene – an activity that may supplant the need for histone epigenetic modifications.

Abstract 859: Development of non-smoking lung cancers by indoor carcinogenic aerosols through epigenetic reprogramming of lung stem cells: Bioinformatics and artificial intelligence analysis

Abstract Several scientific studies discovered the toxic effects of indoor aerosols on different organs’ adult stem cells of the human body. The most importantly, the indoor toxic aerosols comprised of numerous carcinogens namely, sodium dodecyl sulfate, phthalic acids from floor cleaners, formaldehyde, acetaldehyde, benzene, toluene, ethyl benzene, xylenes, from air fresheners, Hydramethylnon, Pyrethrins, imiprothrin, cypermethrin, tetramethrin, prallethrin and permethrin from ant and roach Killer. However, there was a lack of analysis revealing the mechanism of toxic effects and epigenetic reprogramming of human lung stem cells and development of non-smoking lung cancers. In this study, we analyzed the toxic effects of these chemicals and the mechanism of epigenetic reprograming on lung epithelial cells using Comparative Toxico-genomics Database (CTD), database of Environmental Health Perspectives (EHP), National Institute of Environmental Health Sciences (NIEHS), Google search browser with generative artificial intelligence (AI) and other biological informatics methods (Reactome, Cytoscape PSICQUIC services, and ChEMBL database). We observed from CTD analysis that the chemical gene interactions as risk factors from indoor aerosols showed transcriptionally highly expressed of 31 common genes, by phthalic acids, sodium dodecyl sulfate, from the total of 1347 genes, 107 common genes by formaldehyde, acetaldehyde from the total of 4193 genes and all other toxic ingredients of indoor aerosols. The epigenetic mechanism of histone modifications (H3K4me3, H3K9me3, H3K27me3, H3K27ac, H3K36me3, H3K4me1, Hsa-mir-1301 of lung epithelial, and miRNAs have been revealed by NIH Roadmap Epigenomics Mapping Consortium and the lung tissue arrays were analyzed with AI and matplotlib program. The heterogenic adult stem cell reprogramming is regulated by epigenetic bivalent histone modifications at transcript starts sequences (TSS) of target genes and our current study revealed that CD44, CD80, ALDH2, ALDH3A1, ALDH3B2 are epigenetically reprogrammed with close interaction of other genes by these toxic ingredients of indoor aerosols. Therefore, our results are significant for the carcinogenic effects of indoor aerosols causing for development of lung cancer epigenetically, which may give a clue for the prevention and treatment of nonsmoking lung cancer. Citation Format: Juan Anderson, Mariah Delgado, Malcolm Lovett, Maya Saunders, Geovannie Lake, Samuel Darko, Rose M. Stiffin, Ayivi Huisso, Marilyn Sherman, Latoya Appleton, Amalya Mihnea, Swarnava Das, Mohammad M. Algahtani, Ravi Vadapalli, Biswarup Basu, Arunima Biswas, Noor Neha, Madhumita Das, Marco A. Ruiz, Mayur Doke, Jayanta K. Das. Development of non-smoking lung cancers by indoor carcinogenic aerosols through epigenetic reprogramming of lung stem cells: Bioinformatics and artificial intelligence analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 859.

JMJD3 regulate H3K27me3 modification via interacting directly with TET1 to affect spermatogonia self-renewal and proliferation

BackgroundIn epigenetic modification, histone modification and DNA methylation coordinate the regulation of spermatogonium. Not only can methylcytosine dioxygenase 1 (TET1) function as a DNA demethylase, converting 5-methylcytosine to 5-hydroxymethylcytosine, it can also form complexes with other proteins to regulate gene expression. H3K27me3, one of the common histone modifications, is involved in the regulation of stem cell maintenance and tumorigenesis by inhibiting gene transcription.Methodswe examined JMJD3 at both mRNA and protein levels and performed Chip-seq sequencing of H3K27me3 in TET1 overexpressing cells to search for target genes and signaling pathways of its action.ResultsThis study has found that JMJD3 plays a leading role in spermatogonia self-renewal and proliferation: at one extreme, the expression of the self-renewal gene GFRA1 and the proliferation-promoting gene PCNA was upregulated following the overexpression of JMJD3 in spermatogonia; at the other end of the spectrum, the expression of differentiation-promoting gene DAZL was down-regulated. Furthermore, the fact that TET1 and JMJD3 can form a protein complex to interact with H3K27me3 has also been fully proven. Then, through analyzing the sequencing results of CHIP-Seq, we found that TET1 targeted Pramel3 when it interacted with H3K27me3. Besides, TET1 overexpression not only reduced H3K27me3 deposition at Pramel3, but promoted its transcriptional activation as well, and the up-regulation of Pramel3 expression was verified in JMJD3-overexpressing spermatogonia.ConclusionIn summary, our study identified a novel link between TET1 and H3K27me3 and established a Tet1-JMJD3-H3K27me3-Pramel3 axis to regulate spermatogonia self-renewal and proliferation. Judging from the evidence offered above, we can safely conclude that this study provides new ideas for further research regarding the mechanism of spermatogenesis and spermatogenesis disorders on an apparent spectrum.

MicroRNA-93-5p regulates odontogenic differentiation and dentin formation via KDM6B

BackgroundEpigenetic factors influence the odontogenic differentiation of dental pulp stem cells and play indispensable roles during tooth development. Some microRNAs can epigenetically regulate other epigenetic factors like DNA methyltransferases and histone modification enzymes, functioning as epigenetic-microRNAs. In our previous study, microarray analysis suggested microRNA-93-5p (miR-93-5p) was differentially expressed during the bell stage in human tooth germ. Prediction tools indicated that miR-93-5p may target lysine-specific demethylase 6B (KDM6B). Therefore, we explored the role of miR-93-5p as an epi-miRNA in tooth development and further investigated the underlying mechanisms of miR-93-5p in regulating odontogenic differentiation and dentin formation.MethodsThe expression pattern of miR-93-5p and KDM6B of dental pulp stem cells (DPSCs) was examined during tooth development and odontogenic differentiation. Dual luciferase reporter and ChIP-qPCR assay were used to validate the target and downstream regulatory genes of miR-93-5p in human DPSCs (hDPSCs). Histological analyses and qPCR assays were conducted for investigating the effects of miR-93-5p mimic and inhibitor on odontogenic differentiation of hDPSCs. A pulpotomy rat model was further established, microCT and histological analyses were performed to explore the effects of KDM6B-overexpression and miR-93-5p inhibition on the formation of tertiary dentin.ResultsThe expression level of miR-93-5p decreased as odontoblast differentiated, in parallel with elevated expression of histone demethylase KDM6B. In hDPSCs, miR-93-5p overexpression inhibited the odontogenic differentiation and vice versa. MiR-93-5p targeted 3′ untranslated region (UTR) of KDM6B, thereby inhibiting its protein translation. Furthermore, KDM6B bound the promoter region of BMP2 to demethylate H3K27me3 marks and thus upregulated BMP2 transcription. In the rat pulpotomy model, KDM6B-overexpression or miR-93-5p inhibition suppressed H3K27me3 level in DPSCs and consequently promoted the formation of tertiary dentin.ConclusionsMiR-93-5p targets epigenetic regulator KDM6B and regulates H3K27me3 marks on BMP2 promoters, thus modulating the odontogenic differentiation of DPSCs and dentin formation.

Histone acetylation in an Alzheimer’s disease cell model promotes homeostatic amyloid-reducing pathways

Alzheimer’s Disease (AD) is a disorder characterized by cognitive decline, neurodegeneration, and accumulation of amyloid plaques and tau neurofibrillary tangles in the brain. Dysregulation of epigenetic histone modifications may lead to expression of transcriptional programs that play a role either in protecting against disease genesis or in worsening of disease pathology. One such histone modification, acetylation of histone H3 lysine residue 27 (H3K27ac), is primarily localized to genomic enhancer regions and promotes active gene transcription. We previously discovered H3K27ac to be more abundant in AD patient brain tissue compared to the brains of age-matched non-demented controls. In this study, we use iPSC-neurons derived from familial AD patients with an amyloid precursor protein (APP) duplication (APPDup neurons) as a model to study the functional effect of lowering CBP/P300 enzymes that catalyze H3K27ac. We found that homeostatic amyloid-reducing genes were upregulated in the APPDup neurons compared to non-demented controls. We lowered CBP/P300 to reduce H3K27ac, which led to decreased expression of numerous of these homeostatic amyloid-reducing genes, along with increased extracellular secretion of a toxic amyloid-β species, Aβ(1–42). Our findings suggest that epigenomic histone acetylation, including H3K27ac, drives expression of compensatory genetic programs in response to AD-associated insults, specifically those resulting from APP duplication, and thus may play a role in mitigating AD pathology in neurons.

Molecular Mechanisms of Neuroprotection by Ketone Bodies and Ketogenic Diet in Cerebral Ischemia and Neurodegenerative Diseases.

Ketone bodies (KBs), such as acetoacetate and β-hydroxybutyrate, serve as crucial alternative energy sources during glucose deficiency. KBs, generated through ketogenesis in the liver, are metabolized into acetyl-CoA in extrahepatic tissues, entering the tricarboxylic acid cycle and electron transport chain for ATP production. Reduced glucose metabolism and mitochondrial dysfunction correlate with increased neuronal death and brain damage during cerebral ischemia and neurodegeneration. Both KBs and the ketogenic diet (KD) demonstrate neuroprotective effects by orchestrating various cellular processes through metabolic and signaling functions. They enhance mitochondrial function, mitigate oxidative stress and apoptosis, and regulate epigenetic and post-translational modifications of histones and non-histone proteins. Additionally, KBs and KD contribute to reducing neuroinflammation and modulating autophagy, neurotransmission systems, and gut microbiome. This review aims to explore the current understanding of the molecular mechanisms underpinning the neuroprotective effects of KBs and KD against brain damage in cerebral ischemia and neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease.

Phase-separated CCER1 coordinates the histone-to-protamine transition and male fertility

Idiopathic fertility disorders are associated with mutations in various genes. Here, we report that coiled-coil glutamate-rich protein 1 (CCER1), a germline-specific and intrinsically disordered protein (IDP), mediates postmeiotic spermatid differentiation. In contrast, CCER1 deficiency results in defective sperm chromatin compaction and infertility in mice. CCER1 increases transition protein (Tnp1/2) and protamine (Prm1/2) transcription and mediates multiple histone epigenetic modifications during the histone-to-protamine (HTP) transition. Immiscible with heterochromatin in the nucleus, CCER1 self-assembles into a polymer droplet and forms a liquid-liquid phase-separated condensate in the nucleus. Notably, we identified loss-of-function (LoF) variants of human CCER1 (hCCER1) in five patients with nonobstructive azoospermia (NOA) that were absent in 2713 fertile controls. The mutants led to premature termination or frameshift in CCER1 translation, and disrupted condensates in vitro. In conclusion, we propose that nuclear CCER1 is a phase-separated condensate that links histone epigenetic modifications, HTP transitions, chromatin condensation, and male fertility.

Allele‐specific histone acetylation in Alzheimer’s disease brain

AbstractBackgroundAlzheimer’s disease (AD) is associated with cell type‐specific H3K27ac signatures, an epigenetic modification that marks active enhancers and promoters. Genomic regions marked by H3K27ac, particularly enhancers, are enriched for AD genetic risk. We aim to identify nearby genetic variants regulating histone acetylation to better understand the link between genetic risk and disease.MethodFor the first time we have performed allelic specific analysis of histone epigenetic modifications in AD. We used H3K27ac ChIP‐seq data from human post‐mortem entorhinal cortex samples from AD cases (n = 24) and controls (n = 23) (Marzi et al., 2018) to differentiate the histone acetylation signal originating from both alleles in an individual.ResultsWe identified 844 significant loci with allele‐specific histone acetylation by testing individual samples, and 344 by testing across samples. Both sets featured an FDR‐significant acetylation imbalance in a region predicted to be regulating SETD1B, a histone lysine methyltransferase previously found to be elevated in AD patients (Cao et al., 2020). Using linear regression, we also identified 329 SNPs associated with histone acetylation levels. Cell type deconvolution of the overlap between the SNP‐associated H3K27ac regions and genomic regions differentially acetylated in AD highlighted multiple brain cell types. In addition, there was an enrichment for biological processes involving myelination, and cell type‐specific regions were enriched for oligodendrocytes.ConclusionGenetic variants are associated with levels of H3K27ac in genomic regions regulating disease‐related processes.

Interactome of intact chromatosome variants with site-specifically ubiquitylated and acetylated linker histone H1.2.

Post-translational modifications (PTMs) of histones have fundamental effects on chromatin structure and function. While the impact of PTMs on the function of core histones are increasingly well understood, this is much less the case for modifications of linker histone H1, which is at least in part due to a lack of proper tools. In this work, we establish the assembly of intact chromatosomes containing site-specifically ubiquitylated and acetylated linker histone H1.2 variants obtained by a combination of chemical biology approaches. We then use these complexes in a tailored affinity enrichment mass spectrometry workflow to identify and comprehensively characterize chromatosome-specific cellular interactomes and the impact of site-specific linker histone modifications on a proteome-wide scale. We validate and benchmark our approach by western-blotting and by confirming the involvement of chromatin-bound H1.2 in the recruitment of proteins involved in DNA double-strand break repair using an invitro ligation assay. We relate our data to previous work and in particular compare it to data on modification-specific interaction partners of free H1. Taken together, our data supports the role of chromatin-bound H1 as a regulatory protein with distinct functions beyond DNA compaction and constitutes an important resource for future investigations of histone epigenetic modifications.

DeepEpi: Deep Learning Model for Predicting Gene Expression Regulation Based on Epigenetic Histone Modifications

Background: Histone modification is a vital element in gene expression regulation. The way in which these proteins bind to the DNA impacts whether or not a gene may be expressed. Although those factors cannot influence DNA construction, they can influence how it is transcribed. Objective: Each spatial location in DNA has its function, so the spatial arrangement of chromatin modifications affects how the gene can express. Also, gene regulation is affected by the type of histone modification combinations that are present on the gene and depends on the spatial distributional pattern of these modifications and how long these modifications read on a gene region. So, this study aims to know how to model Long-range spatial genome data and model complex dependencies among Histone reads. Methods: The Convolution Neural Network (CNN) is used to model all data features in this paper. It can detect patterns in histones signals and preserve the spatial information of these patterns. It also uses the concept of memory in long short-term memory (LSTM), using vanilla LSTM, Bi-Directional LSTM, or Stacked LSTM to preserve long-range histones signals. Additionally, it tries to combine these methods using ConvLSTM or uses them together with the aid of a self-attention. Results: Based on the results, the combination of CNN, LSTM with the self-attention mechanism obtained an Area under the Curve (AUC) score of 88.87% over 56 cell types. Conclusion: The result outperforms the present state-of-the-art model and provides insight into how combinatorial interactions between histone modification marks can control gene expression. The source code is available at https://github.com/RaniaHamdy/DeepEpi.

РОЛЬ ЭПИГЕНЕТИЧЕСКИХ ФАКТОРОВ В РАЗВИТИИ И ДИАГНОСТИКЕ ИШЕМИЧЕСКОЙ БОЛЕЗНИ СЕРДЦА

Abstract. Introduction. Understanding the role of epigenetic regulation and studying how it affects the pathogenesis of many polygenic diseases have become a breakthrough in modern medicine over the past decade. Today, it is obvious that epigenetic mechanisms, despite their inheritable nature, can become modified under the influence of lifestyle and environment. Epigenetics is the science of inherited body properties that are not related to any changes in the actual nucleotide DNA sequence and can be encoded in the genome rather indirectly than directly. Gaining the knowledge on these mechanisms opened up new opportunities for understanding the origin of some cardiovascular diseases. Promoting this trend has serious consequences for the development and progression of diseases, as well as creates possible new strategies for preventing cardiovascular diseases. Due to this, some fundamental epigenetic regulation mechanisms in the development of coronary heart disease were identified in recent years, which disease is one of the leading causes of mortality in today’s context. Aim. To study the role of the epigenetic mechanisms of early vascular inflammation in the development of coronary heart disease and the prognostic value of epigenetic biomarkers in diagnosing this disease. Material and Methods. We analyzed the findings of studies conducted in 2001-2022 regarding epigenetic mechanisms and their role in the pathogenesis and diagnosis of coronary heart disease, using new epigenetic markers. Sources. PubMed, ResearchGate, eLibrary, Cyberleninka. Results and Discussion. Among all epigenetic mechanisms, DNA methylation, histone modification, and transcription of non-coding RNA sequences, particularly micro-RNA, are currently considered to be most extensively studied and most significant. Conclusion Understanding the basic regulation mechanisms of epigenetic modifications in the development of coronary heart disease will increase knowledge about the etiopathogenesis of this disease and facilitate the transition to personalized medicine.

UHRF1 promotes spindle assembly and chromosome congression by catalyzing EG5 polyubiquitination.

UHRF1 is an epigenetic coordinator bridging DNA methylation and histone modifications. Additionally, UHRF1 regulates DNA replication and cell cycle, and its deletion induces G1/S or G2/M cell cycle arrest. The roles of UHRF1 in the regulation of G2/M transition remain poorly understood. UHRF1 depletion caused chromosome misalignment, thereby inducing cell cycle arrest at mitotic metaphase, and these cells exhibited the defects of spindle geometry, prominently manifested as shorter spindles. Mechanistically, UHRF1 protein directly interacts with EG5, a kinesin motor protein, during mitosis. Furthermore, UHRF1 induced EG5 polyubiquitination at the site of K1034 and further promoted the interaction of EG5 with spindle assembly factor TPX2, thereby ensuring accurate EG5 distribution to the spindles during metaphase. Our study clarifies a novel UHRF1 function as a nuclear protein catalyzing EG5 polyubiquitination for proper spindle architecture and faithful genomic transmission, which is independent of its roles in epigenetic regulation and DNA damage repair inside the nucleus. These findings revealed a previously unknown mechanism of UHRF1 in controlling mitotic spindle architecture and chromosome behavior and provided mechanistic evidence for UHRF1 deletion-mediated G2/M arrest.

Mannan-oligosaccharide induces trained immunity activation and alleviates pathological liver injury in turbot (Scophthalmus maximus)

The liver is one of the principle immune organs in fish, and involves lots of physiological processes. Pathological liver injury is a common symptom in fish farming caused by bacterial infection. Mannan-oligosaccharide (MOS) has been considered as a promising diet additive in aquaculture due to its liver protection. However, the specific mechanism by which MOS protects fish from pathological liver injury remains unknown. In this study, we established a MOS intraperitoneal injection model in turbot (Scophthalmus maximus) and found that MOS-treated turbots exhibited a rapid and elevated inflammatory response during secondary bacterial infection. Besides, MOS treatment caused significant changes in metabolic signaling (such as glycolysis, glutamine metabolism, and fatty acid metabolism) and histone epigenetic modifications (including H3K4me1, H3K4me3 and H3K9me3), which are typical characteristics of trained immunity activation. Moreover, we found an enhanced capability for bacterial clearance in MOS-treated turbot, resulting alleviated phenotypes of liver injury and histopathology changes. Taken together, these findings suggest that MOS might be the inducers of trained immunity in teleost fish, which contributes to protecting turbot from liver injury.

FOXM1 maintains fatty acid homoeostasis through the SET7-H3K4me1-FASN axis

Reprogramming of metabolic genes and subsequent alterations in metabolic phenotypes occur widely in malignant tumours, including glioblastoma (GBM). FOXM1 is a potent transcription factor that plays an oncogenic role by regulating the expression of many genes. As a SET domain containing protein, SET7 is a protein lysine methyltransferase which monomethylates histone proteins and other proteins. The epigenetic modification of histones regulates gene expressions by epigenetically modifying promoters of DNAs and inter vening in tumor development. Activation of FASN increased de novo fatty acid (FA) synthesis, a hallmark of cancer cells. Here, we report that FOXM1 may directly promote the transcription of SET7 and activate SET7-H3K4me1-FASN axis, which results in the maintenance of de novo FA synthesis.

Epigenetic histone modification by butyrate downregulates KIT and attenuates mast cell function.

Short-chain fatty acid butyrate is produced from the bacterial fermentation of indigestible fiber in the intestinal lumen, and it has been shown to attenuate lung inflammation in murine asthma models. Mast cells (MCs) are initiators of inflammatory response to allergens, and they play an important role in asthma. MC survival and proliferation is regulated by its growth factor stem cell factor (SCF), which acts through the receptor, KIT. It has previously been shown that butyrate attenuates the activation of MCs by allergen stimulation. However, how butyrate mechanistically influences SCF signalling to impact MC function remains unknown. Here, we report that butyrate treatment triggered the modification of MC histones via butyrylation and acetylation, and inhibition of histone deacetylase (HDAC) activity. Further, butyrate treatment caused downregulation of SCF receptor KIT and associated phosphorylation, leading to significant attenuation of SCF-mediated MC proliferation, and pro-inflammatory cytokine secretion. Mechanistically, butyrate inhibited MC function by suppressing KIT and downstream p38 and Erk phosphorylation, and it mediated these effects via modification of histones, acting as an HDAC inhibitor and not via its traditional GPR41 (FFAR3) or GPR43 (FFAR2) butyrate receptors. In agreement, the pharmacological inhibition of Class I HDAC (HDAC1/3) mirrored butyrate's effects, suggesting that butyrate impacts MC function by HDAC1/3 inhibition. Taken together, butyrate epigenetically modifies histones and downregulates the SCF/KIT/p38/Erk signalling axis, leading to the attenuation of MC function, validating its ability to suppress MC-mediated inflammation. Therefore, butyrate supplementations could offer a potential treatment strategy for allergy and asthma via epigenetic alterations in MCs.

The role of epigenetic changes in the pathology and treatment of inherited retinal diseases.

Elucidation of the cellular changes that occur in degenerating photoreceptors of people with inherited retinal diseases (IRDs) has been a focus for many research teams, leading to numerous theories on how these changes affect the cell death process. What is clearly emerging from these studies is that there are common denominators across multiple models of IRD, regardless of the underlying genetic mutation. These common markers could open avenues for broad neuroprotective therapeutics to prevent photoreceptor loss and preserve functional vision. In recent years, the role of epigenetic modifications contributing to the pathology of IRDs has been a particular point of interest, due to many studies noting changes in these epigenetic modifications, which coincide with photoreceptor cell death. This review will discuss the two broad categories of epigenetic changes, DNA methylation and histone modifications, that have received particular attention in IRD models. We will review the altered epigenetic regulatory events that are believed to contribute to cell death in IRDs and discuss the therapeutic potential of targeting these alterations.

Frontiers in aging special issue: DNA repair and interventions in aging perspective on "loss of epigenetic information as a cause of mammalian aging".

The recently published article in Cell by the Sinclair lab and collaborators entitled "Loss of Epigenetic Information as a Cause of Mammalian Aging" [1] implicates heritable changes in gene expression as the basis for aging, a postulate consistent with the emerging information theory of aging. Sinclair's group and colleagues induced epigenetic changes, i.e., DNA and histone modifications, via double-strand breaks (DSBs) catalyzed by the I-Pol endonuclease at specific genomic loci. The genomic DNA breaks, introduced without inducing insertion or deletion mutations (indels) in a mouse model, were targeted to 19 non-coding regions and one region in ribosomal DNA (rDNA), the latter shown to not have a significant effect on the function or transcription of rDNA [1]. With that experimental model in place, the authors present experimental evidence supporting a model that epigenetic changes drive aging via this inducible DNA break mechanism. After demonstrating the phenotypic alterations of this accelerated aging, they attempt to reverse selective phenotypes by resetting the altered epigenetic landscape. Establishing a causal relationship between epigenetic changes and aging, and how this connection might be manipulated to overturn cellular features of aging, is provocative and merits further study.