DNA methylation dynamics of long noncoding RNA during human fetal development

Colorectal cancer microbiome programs DNA methylation of host cells by affecting methyl donor metabolism

BACKGROUND

Colorectal cancer (CRC) arises from complex interactions between host and environment, which include the gut and tissue microbiome. It is hypothesized that epigenetic regulation by gut microbiota is a fundamental interface by which commensal microbes dynamically influence intestinal biology. The aim of this study is to explore the interplay between gut and tissue microbiota and host DNA methylation in CRC.

METHODS

Metagenomic sequencing of fecal samples was performed on matched CRC patients (n = 18) and healthy controls (n = 18). Additionally, tissue microbiome was profiled with 16S rRNA gene sequencing on tumor (n = 24) and tumor-adjacent normal (n = 24) tissues of CRC patients, while host DNA methylation was assessed through whole-genome bisulfite sequencing (WGBS) in a subset of 13 individuals.

RESULTS

Our analysis revealed substantial alterations in the DNA methylome of CRC tissues compared to adjacent normal tissues. An extensive meta-analysis, incorporating publicly available and in-house data, identified significant shifts in microbial-derived methyl donor-related pathways between tumor and adjacent normal tissues. Of note, we observed a pronounced enrichment of microbial-associated CpGs within the promoter regions of genes in adjacent normal tissues, a phenomenon notably absent in tumor tissues. Furthermore, we established consistent and recurring associations between methylation patterns of tumor-related genes and specific bacterial taxa.

CONCLUSIONS

This study emphasizes the pivotal role of the gut microbiota and pathogenic bacteria in dynamically shaping DNA methylation patterns, impacting physiological homeostasis, and contributing to CRC tumorigenesis. These findings provide valuable insights into the intricate host-environment interactions in CRC development and offer potential avenues for therapeutic interventions in this disease.

Epigenetic control of LncRNA NEAT1 enables cardiac fibroblast pyroptosis and cardiac fibrosis

Cardiac fibroblasts (CFs) drive extracellular matrix remodeling after inflammatory injury, leading to cardiac fibrosis and diastolic dysfunction. Recent studies described the role of epigenetics in cardiac fibrosis. Nevertheless, detailed reports on epigenetics regulating CFs pyroptosis and describing their implication in cardiac fibrosis are still unclear. Here, we found that DNMT3A reduces the expression of lncRNA Neat1 and promotes the NLRP3 axis leading to CFs pyroptosis, using cultured cells, animal models, and clinical samples to shed light on the underlying mechanism. We report that pyroptosis-related genes are increased explicitly in cardiac fibrosis tissue and LPS-treated CFs, while lncRNA Neat1 decreased. Mechanistically, we show that loss of DNMT3A or overexpression of lncRNA Neat1 in CFs after LPS treatment significantly enhances CFs pyroptosis and the production of pyroptosis-related markers in vitro. It has been demonstrated that DNMT3A can decrease lncRNA Neat1, promoting NLRP3 axis activation in CFs treated with LPS. In sum, this study is the first to identify that DNMT3A methylation decreases the expression of lncRNA Neat1 and promotes CFs pyroptosis and cardiac fibrosis, suggesting that DNMT3A and NEAT1 may function as an anti-fibrotic therapy target in cardiac fibrosis.

Analysis of lncRNAs and mRNA Expression in the ZBTB1 Knockout Monoclonal EL4 Cell Line and Combined Analysis With miRNAs and circRNAs

In previous experiments, we identified the effect of deletion of the Zbtb1 gene on circRNAs and microRNAs. In this study, we examined the expression profiles of lncRNAs and mRNAs using the RNA-seq method for Zbtb1-deficient EL4 cells and performed a clustering analysis of differentially expressed lncRNAs and mRNAs. GO term histograms and KEGG scatter plots were drawn. For the experimental results, a joint analysis was performed, which predicted the regulatory relationships among lncRNAs, mRNAs, microRNAs and circRNAs. For the regulatory relationship between lncRNAs and target genes, the chromatin structure and the degree of openness were verified for the possible target gene locations regulated by lncRNA using experimental methods such as Hi-C and ATAC-seq. Ultimately, the possible differential regulation of the Brcal and Dennd5d genes by lncRNAs and the differential changes in transcription factor binding sites in the promoter region were identified. For neRNA-regulated target genes with significantly differentially expressed mRNAs, a combined screen was performed, and the final obtained candidate target genes were subjected to GO and KEGG term enrichment analyses. Our results illustrate that the Zbtb1 gene can not only function as a regulatory factor but also regulate EL4 cells from multiple perspectives based on ceRNA theory.