N6-methyladenosine methyltransferase METTL3 affects the phenotype of cerebral arteriovenous malformation via modulating Notch signaling pathway

Abstract

Background: Cerebral arteriovenous malformation (AVM) is a serious life-threatening congenital cerebrovascular disease. Specific anatomical features, such as nidus size, location, and venous drainage, have been validated to affect treatment outcomes. Until recently, molecular biomarkers and corresponding molecular mechanism related to anatomical features and treatment outcomes remain unknown. Methods: RNA N6-methyladenosine (m 6 A) Methyltransferase METTL3 was identified as a differentially expressed gene in groups with different lesion sizes by analyzing the transcriptome sequencing (RNA-seq) data. Tube formation and wound healing assays were performed to investigate the effect of METTL3 on angiogenesis. In addition, Methylated RNA Immunoprecipitation Sequencing technology (MeRIP-seq) was performed to screen downstream targets of METTL3 in endothelial cells and to fully clarify the specific underlying molecular mechanisms affecting the phenotype of cerebral AVM. Results: In the current study, we found that the expression level of METTL3 was reduced in the larger pathological tissues of cerebral AVMs. Moreover, knockdown of METTL3 significantly affected angiogenesis of the human endothelial cells. Mechanistically, down-regulation of METTL3 reduced the level of heterodimeric Notch E3 ubiquitin ligase formed by DTX1 and DTX3L, thereby continuously activating the Notch signaling pathway. Ultimately, the up-regulated downstream genes of Notch signaling pathway dramatically affected the angiogenesis of endothelial cells. In addition, we demonstrated that blocking Notch pathway with DAPT could restore the phenotype of METTL3 deficient endothelial cells. Conclusions: Our findings revealed the mechanism by which m 6 A modification regulated the angiogenesis and might provide potential biomarkers to predict the outcome of treatment, as well as provide suitable pharmacological targets for preventing the formation and progression of cerebral AVM.

Alteration of N6 -Methyladenosine mRNA Methylation in a Rat Model of Cerebral Ischemia–Reperfusion Injury

“… Si et al (2020) found that METTL3-mediated miRNA m6A methylation promotes stress granule formation and reduces the apoptosis of injury neurons in the early stage of acute IS. Furthermore, Wang et al (2020a , b) found that the expression levels of METTL3 and WTAP were reduced in the larger pathological tissue of cerebral AVMs. Mechanistically, the lack of METTL3 reduced the level of heterodimeric Notch E3 ubiquitin ligase, thereby continuously activating the Notch signaling pathway, which affects the angiogenesis of endothelial cells.…”

Epitranscriptomic regulation by m6A RNA methylation in brain development and diseases

“…105 An inverse correlation was also observed between METTL3 expression and the nidus size of cerebral AVMs. 106 Notch pathway regulator DTX3L was implicated in AVM formation, and in METTL3-deficient endothelial cells, DTX3L mRNA was observed to be hypomethylated and silenced, indicating that m 6 A is crucial for its stability. 106 Furthermore, m 6 A SNP in IRF6 transcript correlated with intracerebral hemorrhage in humans.…”

“…106 Notch pathway regulator DTX3L was implicated in AVM formation, and in METTL3-deficient endothelial cells, DTX3L mRNA was observed to be hypomethylated and silenced, indicating that m 6 A is crucial for its stability. 106 Furthermore, m 6 A SNP in IRF6 transcript correlated with intracerebral hemorrhage in humans. 101 Collectively, these studies indicate the role of m 6 A methylation in stroke incidence and post-stroke brain damage.…”

Prognostic Significance of Homocysteine Level on Neurological Outcome in Brain Arteriovenous Malformations

“…When the classic Spetzler-Martin (SM) grading system [17], supplementary scale [18], and even with evolving fMRI-based HDVL grading scale combined with lesion-to eloquence distance (LED) are added [19], the evaluation becomes accurate but tedious at the same time. And there are some objectively advanced biomarkers, such as S100B, matrix metalloproteinase-9 (MMP-9), interleukin-1 beta (IL-1β), vascular endothelial growth factor (VEGF), and N6-methyladenosine methyltransferase 3 (METTL3) [12,[20][21][22], which were proposed to be the predictors for the in-hospital complications and neurological outcomes. However, these indicators were unable to directly provide guidance for clinical practice.…”