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Published on: February 15, 2022
YTH N6-methyladenosine RNA Binding Protein 1 Inhibits Smooth Muscle Cell Phenotypic Modulation and Neointimal
Kai Tian1, Dunpeng Cai1, Shuang Yang2
1Department of Surgery, School of Medicine, University of Missouri, Columbia, MO 65212, USA.
Abstract:
Smooth muscle cell (SMC) phenotypic transition contributes to several major vascular diseases such as intimal hyperplasia and restenosis, atherosclerosis, and aneurysm. However, the molecular mechanisms underlying this process are not fully understood. The objectives of this study are to determine the role of mRNA N6-methyladenosine (m6A) modification in SMC phenotypic modulation and injury-induced neointima formation. By using an m6A quantification kit, we found that m6A levels are altered during the early stage of SMC phenotypic modulation. RNA sequencing revealed that m6A modifications in the mRNAs of 708 genes are elevated while modifications in the mRNAs of 300 genes are decreased. These modifications occur in genes widely distributed in most chromosomes and involved in many cellular processes and signaling/gene regulations. Meanwhile, the regulators for m6A modifications are altered by PDGF-BB, a known factor inducing SMC phenotypic modulation. Although m6A writers and erasers are not altered during SMC phenotypic modulation, m6A reader YTHDF1 is dramatically reduced as early as 12 h following PDGF-BB treatment, a time much earlier than the downregulation of SMC contractile proteins. Importantly, the overexpression of YTHDF1 reverses the expression of SMC contractile proteins, suggesting a restoration of contractile SMC phenotype. By using a rat carotid artery balloon-injury model, we found that injury significantly decreases YTHDF1 levels in the medial SMCs while inducing neointima formation. Of significance, restoring YTHDF1 expression through lentiviral transduction blocks injury-induced neointima formation. Moreover, YTHDF1 delivery restores the expression of SMC contractile proteins that is diminished in arterial media layers due to the injury. These data demonstrate that YTHDF1 plays a protective role in maintaining the contractile SMC phenotype and vascular homeostasis during injury-induced pathological vascular remodeling.
Insights
Messenger RNA (mRNA) N6-methyladenosine (m6A) modification, specifically the reader YTHDF1, plays a crucial role in maintaining smooth muscle cell (SMC) phenotype and preventing vascular remodeling after injury.
Area of Science:
- Vascular Biology
- Epigenetics
- Molecular Medicine
Background:
- Smooth muscle cell (SMC) phenotypic transition is implicated in vascular diseases like atherosclerosis and aneurysm.
- The molecular mechanisms driving SMC phenotypic modulation remain incompletely understood.
- N6-methyladenosine (m6A) modification of mRNA is a key regulatory mechanism in cellular processes.
Purpose of the Study:
- To investigate the role of mRNA m6A modification in SMC phenotypic modulation.
- To determine the involvement of m6A in injury-induced neointima formation.
- To elucidate the function of m6A readers, specifically YTHDF1, in vascular homeostasis.
Main Methods:
- Quantification of m6A levels in SMCs during phenotypic modulation.
- RNA sequencing to identify genes with altered m6A modification.
- Assessment of m6A regulator expression, including YTHDF1, following PDGF-BB treatment.
- Utilizing a rat carotid artery balloon-injury model to study neointima formation.
- Investigating the effect of YTHDF1 overexpression and delivery on SMC phenotype and neointima formation.
Main Results:
- m6A levels are altered during early SMC phenotypic modulation, with changes in hundreds of genes.
- PDGF-BB, a modulator of SMC phenotype, affects m6A regulators.
- YTHDF1 expression is significantly reduced early in PDGF-BB treatment and after arterial injury.
- Overexpression of YTHDF1 restores SMC contractile protein expression.
- Restoring YTHDF1 levels in vivo blocks injury-induced neointima formation and preserves SMC phenotype.
Conclusions:
- YTHDF1 is a critical regulator of SMC phenotype maintenance.
- Reduced YTHDF1 expression contributes to pathological vascular remodeling and neointima formation.
- YTHDF1 plays a protective role in vascular homeostasis by preserving the contractile SMC phenotype during injury.
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