The Effect of N6-Methyladenosine Regulators and m6A Reader YTHDC1-Mediated N6-Methyladenosine Modification Is Involved in Oxidative Stress in Human Aortic Dissection

Development and validation of a 6-gene signature derived from RNA modification-associated genes for the diagnosis of Acute Stanford Type A Aortic Dissection

Background

Acute Stanford Type A Aortic Dissection (ATAAD) is a critical medical emergency characterized by significant morbidity and mortality. This study aims to identify specific gene expression patterns and RNA modification associated with ATAAD.

Methods

The GSE153434 dataset was obtained from the Gene Expression Omnibus (GEO) database. Differential expression analysis was conducted to identify differential expression genes (DEGs) associated with ATAAD. To validate the involvement of RNA modification in ATAAD, RNA modification-related genes (M6A, M1A, M5C, APA, A-to-I) were acquired from GeneCards, following by Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis. A gene prediction signature consisting of key genes was established, and Real-time PCR was used to validate the gene expression in clinical samples. The patients were then divided into high and low-risk groups, and subsequent enrichment analysis, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Set Enrichment Analysis (GSEA), Gene Set Variation Analysis (GSVA), and assessments of immune infiltration. A co-expression network analysis (WGCNA) was performed to explore gene-phenotype relationships and identify key genes.

Results

A total of 45 RNA modification genes were acquired. Six gene signatures (YTHDC1, WTAP, CFI, ADARB1, ADARB2, TET3) were developed for ATAAD diagnosis and risk stratification. Enrichment analysis suggested the potential involvement of inflammation and extracellular matrix pathways in the progression of ATAAD. The incorporation of pertinent genes from the GSE147026 dataset into the six-gene signature further validated the model's effectiveness. A significant upregulation in WTAP, ADARB2, and TET3 expression, whereas YTHDC1 exhibited a noteworthy downregulation in the ATAAD group.

Conclusion

Six-gene signature could serve as an efficient model for predicting the diagnosis of ATAAD.

Unravelling the impact of RNA methylation genetic and epigenetic machinery in the treatment of cardiomyopathy

Cardiomyopathy (CM) represents a heterogeneous group of diseases primarily affecting cardiac structure and function, with genetic and epigenetic dysregulation playing a pivotal role in its pathogenesis. Emerging evidence from the burgeoning field of epitranscriptomics has brought to light the significant impact of various RNA modifications, notably N6-methyladenosine (m6A), 5-methylcytosine (m5C), N7-methylguanosine (m7G), N1-methyladenosine (m1A), 2'-O-methylation (Nm), and 6,2'-O-dimethyladenosine (m6Am), on cardiomyocyte function and the broader processes of cardiac and vascular remodelling. These modifications have been shown to influence key pathological mechanisms including mitochondrial dysfunction, oxidative stress, cardiomyocyte apoptosis, inflammation, immune response, and myocardial fibrosis. Importantly, aberrations in the RNA methylation machinery have been observed in human CM cases and animal models, highlighting the critical role of RNA methylating enzymes and their potential as therapeutic targets or biomarkers for CM. This review underscores the necessity for a deeper understanding of RNA methylation processes in the context of CM, to illuminate novel therapeutic avenues and diagnostic tools, thereby addressing a significant gap in the current management strategies for this complex disease.

WTAP and m6A-modified circRNAs modulation during stress response in acute myeloid leukemia progenitor cells

N6-methyladenosine (m6A) is one of the most prevalent and conserved RNA modifications. It controls several biological processes, including the biogenesis and function of circular RNAs (circRNAs), which are a class of covalently closed-single stranded RNAs. Several studies have revealed that proteotoxic stress response induction could be a relevant anticancer therapy in Acute Myeloid Leukemia (AML). Furthermore, a strong molecular interaction between the m6A mRNA modification factors and the suppression of the proteotoxic stress response has emerged. Since the proteasome inhibition leading to the imbalance in protein homeostasis is strictly linked to the stress response induction, we investigated the role of Bortezomib (Btz) on m6A regulation and in particular its impact on the modulation of m6A-modified circRNAs expression. Here, we show that treating AML cells with Btz downregulated the expression of the m6A regulator WTAP at translational level, mainly because of increased oxidative stress. Indeed, Btz treatment promoted oxidative stress, with ROS generation and HMOX-1 activation and administration of the reducing agent N-acetylcysteine restored WTAP expression. Additionally, we identified m6A-modified circRNAs modulated by Btz treatment, including circHIPK3, which is implicated in protein folding and oxidative stress regulation. These results highlight the intricate molecular networks involved in oxidative and ER stress induction in AML cells following proteotoxic stress response, laying the groundwork for future therapeutic strategies targeting these pathways.

Endothelial downregulation of nuclear m6A reader YTHDC1 promotes pulmonary vascular remodeling in sugen hypoxia model of pulmonary hypertension

Background

Pulmonary hypertension (PH) is characterized with vascular remodeling, which is intiated by vascular endothelial dysfunction. N6-methyladenosine (m6A) modification mediates gene expression in many ways including mediating RNA degradation, splicing, nuclear export et al. m6A modification have been found to be associated with the development of PH. However, the role of m6A regulators in pulmonary artery endothelial cells (PAECs) dysfunction of PH is still under research.

Methods

The expression levels of m6A regulators in PAECs were analyzed with the single-cell sequencing Data(scRNA). Next, the target differentially expressed genes (DEGs) of m6A regulators in PAECs were functionally annotated. The analysis of cellular interactions included the examination of receptor-ligand pairs regulated by m6A regulators. Pseudo-time trajectory analyses and a ceRNA network involving lncRNAs, miRNAs, and mRNAs were conducted in PAECs. Furthermore, microarray data (GSE180169) for Sugen Hypoxia PH (SuHx PH) mouse models was screened for DEGs and m6A regulators in PAECs. Moreover, the expression of YTHDC1 in the lung samples of SuHx PH models was determined using immunofluorescence. In vitro, the mRNA expression of YTHDC1 in HPAECs under hypoxia conditions was detected. The effect of YTHDC1 recombinant protein on HPAEC proliferation was detected by Cell Counting Kit-8 (CCK8).

Results

Dysregulation of m6A regulators was observed in mouse PAECs. The m6A reader of YTHDC1 was decreased in PAECs in scRNA data and RNAseq data of isolated PAECs of SuHx PH models. Downregulation of YTHDC1 was caused by hypoxia in PAECs in vitro and similar results was observed in PAECs of SuHx PH mouse models. Next, YTHDC1 recombinant protein was found to inhibit HPAECs proliferation. The DEGs targeted by YTHDC1 were enriched in angiogenesis, endothelial cell migration, fluid shear stress, and stem cell maintenance. Analysis indicates that interactions among endothelial cells, smooth muscle cells, fibroblasts, and immune cells, mediated by specific YTHDC1 target genes (e.g., PTPRC-MRC1, ITBG2-ICAM1, COL4A1-CD44), contribute to PH development. Also, the YTHDC1 expression were consistent with Thioredoxin interacting protein (TXNIP). What's more, the predicted transcription factors showed that NFKB1, Foxd3 may be involved in the regulation of YTHDC1. Lastly, our data suggest that YTHDC1 may be involved in regulating PAECs dysfunction through lncRNA/miRNA/mRNA network.

Conclusion

For the first time, we analyzed changes in the expression and biological functions of m6A regulators in SuHx PH mouse models. We causatively linked YTHDC1 to PAECs dysfunction, providing novel insight into and opportunities to diagnose and treat PH.

Identification of the relationship between single-cell N6-methyladenosine regulators and the infiltrating immune cells in esophageal carcinoma

Background

N6-methyladenosine (m⁶A) RNA methylation plays a crucial role in important genomic processes in a variety of malignancies. However, the characterization of m⁶A with infiltrating immune cells in the tumor microenvironment (TME) in esophageal squamous carcinoma (ESCC) remains unknown.

Methods

The single-cell transcriptome data from five ESCC patients in our hospital were analyzed, and TME clusters associated with prognosis and immune checkpoint genes were investigated. Cell isolation and qPCR were conducted to validate the gene characterization in different cells.

Results

According to distinct biological processes and marker genes, macrophages, T cells, and B cells clustered into three to four different subgroups. In addition, we demonstrated that m⁶A RNA methylation regulators were strongly related to the clinical and biological features of ESCC. Analysis of transcriptome data revealed that m⁶A-mediated TME cell subsets had high predictive value and showed a close relationship with immune checkpoint genes. The validation results from qPCR demonstrated the characteristics of essential genes. CellChat analysis revealed that RNA from TME cells m⁶A methylation-associated cell subtypes had substantial and diversified interactions with cancer cells. Further investigation revealed that MIF- (CD74+CXCR4) and MIF- (CD74⁺CD44) ligand-receptor pairings facilitated communication between m⁶A-associated subtypes of TME cells and cancer cells.

Conclusion

Overall, our study demonstrated for the first time the function of m⁶A methylation-mediated intercellular communication in the microenvironment of tumors in controlling tumor development and anti-tumor immune regulation in ESCC.