Explore the vast range of titles available.

Epigenetic deregulation of α‐synuclein plays a key role in Parkinson’s disease (PD). Analysis of the SNCA promoter using the ENCODE database revealed the presence of important histone post‐translational modifications (PTMs) including transcription‐promoting marks, H3K4me3 and H3K27ac, and repressive mark, H3K27me3. We investigated these histone marks in post‐mortem brains of controls and PD patients and observed that only H3K4me3 was significantly elevated at the SNCA promoter of the substantia nigra (SN) of PD patients both in punch biopsy and in NeuN‐positive neuronal nuclei samples. To understand the importance of H3K4me3 in regulation of α‐synuclein, we developed CRISPR/dCas9‐based locus‐specific H3K4me3 demethylating system where the catalytic domain of JARID1A was recruited to the SNCA promoter. This CRISPR/dCas9 SunTag‐JARID1A significantly reduced H3K4me3 at SNCA promoter and concomitantly decreased α‐synuclein both in the neuronal cell line SH‐SY5Y and idiopathic PD‐iPSC derived dopaminergic neurons. In sum, this study indicates that α‐synuclein expression in PD is controlled by SNCA ’s histone PTMs and modulation of the histone landscape of SNCA can reduce α‐synuclein expression. Synopsis Histone posttranslational modifications play a major role in the regulation of α‐synuclein expression in Parkinson’s disease (PD). Locus‐specific editing of H3K4me3 at the SNCA promoter reverts the deregulated expression of α‐synuclein in neurons in the context of PD. α‐synuclein expression is controlled by epigenetic regulation. H3K4me3 is heavily enriched at the SNCA promoter in PD patient brains. Locus‐specific editing of H3K4me3 reduces neuronal α‐synuclein expression in PD. Graphical Abstract Histone posttranslational modifications play a major role in the regulation of α‐synuclein expression in Parkinson’s disease (PD). Locus‐specific editing of H3K4me3 at the SNCA promoter reverts the deregulated expression of α‐synuclein in neurons in the context of PD.

Brain tumors are one of the most severe types of malignant tumors and glioma accounts for ~80% of malignant brain tumors. The current treatment methods for glioma are limited and patients with glioma often experience relapse following treatment, which leads to a poor prognosis for these patients. Therefore, novel therapeutic targets and methods urgently need to be explored. The present review screened studies that mainly focused on the epigenetic regulation of small guanosine triphosphate (GTP)ase in glioma. These small GTPases participate in most cellular biological processes, including differentiation, proliferation, cell migration, apoptosis, vesicle and organelle dynamics and transport, nuclear dynamics and cytoskeleton regulation. Due to the diversity and importance of the biological functions of small GTPases, an increasing number of studies have focused on them; however, the incidence of changes in the gene structure of small GTPases is considered to be low in glioma. Several studies have shown that the abnormal expression of genes encoding small GTPases is often influenced by epigenetic regulation in glioma. Epigenetic regulation is a dynamic and reversible process, which implies that the reversal of abnormal epigenetic modifications is a potential treatment strategy for glioma. These previous studies, which are summarized in the present review, not only provide new therapeutic targets and prognostic markers, but also provide information regarding the treatment of glioma. The current review may provide valuable insights for future research and promote the clinical translation of relevant research results.

Backgroud Glioblastoma multiforme (GBM) is among the most aggressive cancers, with current treatments limited in efficacy. A significant hurdle in the treatment of GBM is the resistance to the chemotherapeutic agent temozolomide (TMZ). The methylation status of the MGMT promoter has been implicated as a critical biomarker of response to TMZ. Methods To explore the mechanisms underlying resistance, we developed two TMZ‐resistant GBM cell lines through a gradual increase in TMZ exposure. Transcriptome sequencing of TMZ‐resistant cell lines revealed that alterations in histone post‐translational modifications might be instrumental in conferring TMZ resistance. Subsequently, multi‐omics analysis suggests a strong association between histone H3 lysine 9 acetylation (H3K9ac) levels and TMZ resistance. Results We observed a significant correlation between the expression of H3K9ac and MGMT, particularly in the unmethylated MGMT promoter samples. More importantly, our findings suggest that H3K9ac may enhance MGMT transcription by facilitating the recruitment of the SP1 transcription factor to the MGMT transcription factor binding site. Additionally, by analyzing single‐cell transcriptomics data from matched primary and recurrent GBM tumors treated with TMZ, we modeled the molecular shifts occurring upon tumor recurrence. We also noted a reduction in tumor stem cell characteristics, accompanied by an increase in H3K9ac, SP1, and MGMT levels, underscoring the potential role of H3K9ac in tumor relapse following TMZ therapy. Conclusions The increase in H3K9ac appears to enhance the recruitment of the transcription factor SP1 to its binding sites within the MGMT locus, consequently upregulating MGMT expression and driving TMZ resistance in GBM. The acetylation of histone H3 at lysine 9 leads to an open chromatin structure at the MGMT gene locus, facilitating the binding of transcription factors SP1 to the promoter and enhancer regions, resulting in increased transcription of MGMT, thereby contributing to the TMZ resistance in GBM cells.

Fusarium is a species-rich group of mycotoxigenic plant pathogens that ranks as one of the most economically important fungal genera in the world. During growth and infection, they are able to produce a vast spectrum of low-molecular-weight compounds, so-called secondary metabolites (SMs). SMs often comprise toxic compounds (i.e., mycotoxins) that contaminate precious food and feed sources and cause adverse health effects in humans and livestock. In this context, understanding the regulation of their biosynthesis is crucial for the development of cropping strategies that aim at minimizing mycotoxin contamination in the field. Nevertheless, currently, only a fraction of SMs have been identified, and even fewer are considered for regular monitoring by regulatory authorities. Limitations to exploit their full chemical potential arise from the fact that the genes involved in their biosynthesis are often silent under standard laboratory conditions and only induced upon specific stimuli mimicking natural conditions in which biosynthesis of the respective SM becomes advantageous for the producer. This implies a complex regulatory network. Several components of these gene networks have been studied in the past, thereby greatly advancing the understanding of SM gene regulation and mycotoxin biosynthesis in general. This review aims at summarizing the latest advances in SM research in these notorious plant pathogens with a focus on chromatin structure.

Spermatozoa (SPZ) are motile cells, characterized by a cargo of epigenetic information including histone post-translational modifications (histone PTMs) and non-coding RNAs. Specific histone PTMs are present in developing germ cells, with a key role in spermatogenic events such as self-renewal and commitment of spermatogonia (SPG), meiotic recombination, nuclear condensation in spermatids (SPT). Nuclear condensation is related to chromatin remodeling events and requires a massive histone-to-protamine exchange. After this event a small percentage of chromatin is condensed by histones and SPZ contain nucleoprotamines and a small fraction of nucleohistone chromatin carrying a landascape of histone PTMs. Circular RNAs (circRNAs), a new class of non-coding RNAs, characterized by a nonlinear back-spliced junction, able to play as microRNA (miRNA) sponges, protein scaffolds and translation templates, have been recently characterized in both human and mouse SPZ. Since their abundance in eukaryote tissues, it is challenging to deepen their biological function, especially in the field of reproduction. Here we review the critical role of histone PTMs in male germ cells and the profile of circRNAs in mouse and human SPZ. Furthermore, we discuss their suggested role as novel epigenetic biomarkers to assess sperm quality and improve artificial insemination procedure.

Epigenetic alterations are common in prostate cancer (PCa) and seem to contribute decisively to its initiation and progression. Moreover, aberrant promoter methylation is a promising biomarker for non‐invasive screening. Herein, we sought to characterize EFEMP1 as biomarker for PCa, unveiling its biological relevance in prostate carcinogenesis. Microarray analyses of treated PCa cell lines and primary tissues enabled the selection of differentially methylated genes, among which EFEMP1 was further validated by MSP and bisulfite sequencing. Assessment of biomarker performance was accomplished by qMSP. Expression analysis of EFEMP1 and characterization of histone marks were performed in tissue samples and cancer cell lines to determine the impact of epigenetic mechanisms on EFEMP1 transcriptional regulation. Phenotypic assays, using transfected cell lines, permitted the evaluation of EFEMP1's role in PCa development. EFEMP1 methylation assay discriminated PCa from normal prostate tissue (NPT; P < 0.001, Kruskall–Wallis test) and renal and bladder cancers (96% sensitivity and 98% specificity). EFEMP1 transcription levels inversely correlated with promoter methylation and histone deacetylation, suggesting that both epigenetic mechanisms are involved in gene regulation. Phenotypic assays showed that EFEMP1 de novo expression reduces malignant phenotype of PCa cells. EFEMP1 promoter methylation is prevalent in PCa and accurately discriminates PCa from non‐cancerous prostate tissues and other urological neoplasms. This epigenetic alteration occurs early in prostate carcinogenesis and, in association with histone deacetylation, progressively leads to gene down‐regulation, fostering cell proliferation, invasion and evasion of apoptosis.

The emergence of a nucleosome-based chromatin structure accompanied the evolutionary transition from prokaryotes to eukaryotes. In this scenario, histones became the heart of the complex and precisely timed coordination between chromatin architecture and functions during adaptive responses to environmental influence by means of epigenetic mechanisms. Notably, such an epigenetic machinery involves an overwhelming number of post-translational modifications at multiple residues of core and linker histones. This review aims to comprehensively describe old and recent evidence in this exciting field of research. In particular, histone post-translational modification establishing/removal mechanisms, their genomic locations and implication in nucleosome dynamics and chromatin-based processes, as well as their harmonious combination and interdependence will be discussed.

In this review, we comprehensively present the function of epigenetic regulations in normal placental development as well as in a prominent disease of placental origin, preeclampsia (PE). We describe current progress concerning the impact of DNA methylation, non-coding RNA (with a special emphasis on long non-coding RNA (lncRNA) and microRNA (miRNA)) and more marginally histone post-translational modifications, in the processes leading to normal and abnormal placental function. We also explore the potential use of epigenetic marks circulating in the maternal blood flow as putative biomarkers able to prognosticate the onset of PE, as well as classifying it according to its severity. The correlation between epigenetic marks and impacts on gene expression is systematically evaluated for the different epigenetic marks analyzed.

Background Histone lactylation has been recently described as a novel histone post-translational modification linking cellular metabolism to epigenetic regulation. Results Given the expected relevance of this modification and current limited knowledge of its function, we generate genome-wide datasets of H3K18la distribution in various in vitro and in vivo samples, including mouse embryonic stem cells, macrophages, adipocytes, and mouse and human skeletal muscle. We compare them to profiles of well-established histone modifications and gene expression patterns. Supervised and unsupervised bioinformatics analysis shows that global H3K18la distribution resembles H3K27ac, although we also find notable differences. H3K18la marks active CpG island-containing promoters of highly expressed genes across most tissues assessed, including many housekeeping genes, and positively correlates with H3K27ac and H3K4me3 as well as with gene expression. In addition, H3K18la is enriched at active enhancers that lie in proximity to genes that are functionally important for the respective tissue. Conclusions Overall, our data suggests that H3K18la is not only a marker for active promoters, but also a mark of tissue specific active enhancers.

We have a limited understanding of how cells mark and identify newly replicated genomic loci that have a sister chromatid; here, unmethylated K20 in the tail of new histone H4 is shown to serve as a signature of post-replicative chromatin, which is specifically recognized by the homologous recombination complex TONSL–MMS22L. A marker for post-replicative chromatin We have a limited understanding of how cells mark and identify newly replicated genomic loci that have a sister chromatid. Here, Anja Groth and colleagues show that histone H4 tails unmethylated at lysine 20 (H4K20me0) serve as a signature of post-replicative chromatin and are specific to new histones incorporated during DNA replication. H4K20me0 is specifically recognized by a 'reader' domain of the TONSL–MMS22L homologous recombination complex, enabling differentiation of pre- and post-replicative chromatin, and allowing TONSL to function as a histone chaperone or guide repair of damaged replication forks. After DNA replication, chromosomal processes including DNA repair and transcription take place in the context of sister chromatids. While cell cycle regulation can guide these processes globally, mechanisms to distinguish pre- and post-replicative states locally remain unknown. Here we reveal that new histones incorporated during DNA replication provide a signature of post-replicative chromatin, read by the human TONSL–MMS22L 1 , 2 , 3 , 4 homologous recombination complex. We identify the TONSL ankyrin repeat domain (ARD) as a reader of histone H4 tails unmethylated at K20 (H4K20me0), which are specific to new histones incorporated during DNA replication and mark post-replicative chromatin until the G2/M phase of the cell cycle. Accordingly, TONSL–MMS22L binds new histones H3–H4 both before and after incorporation into nucleosomes, remaining on replicated chromatin until late G2/M. H4K20me0 recognition is required for TONSL–MMS22L binding to chromatin and accumulation at challenged replication forks and DNA lesions. Consequently, TONSL ARD mutants are toxic, compromising genome stability, cell viability and resistance to replication stress. Together, these data reveal a histone-reader-based mechanism for recognizing the post-replicative state, offering a new angle to understand DNA repair with the potential for targeted cancer therapy.