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Smooth Muscle Ythdf2 Abrogation Ameliorates Pulmonary Vascular Remodeling by Regulating Myadm Transcript Stability
Jie Wang1,2, Yueyao Shen1, Yuhui Zhang1
1Department of Forensic Medicine (J.W., Y.S., Y.Z., D.L., Y.Y., F.C., L.H.), Nanjing Medical University, China.
Background:
The N6-methyladenosine (m6A) modification of RNA and its regulators have important roles in the pathogenesis of pulmonary hypertension (PH). Ythdf2 (YTH N6-methyladenosine RNA binding protein 2) is best known for its role in degrading m6A-modified mRNAs such as Hmox1 mRNA, which leads to alternative activation of macrophages in PH. Recent studies have also linked Ythdf2 to the proliferation of pulmonary artery smooth muscle cells (PASMCs). However, its specific roles in PASMCs and downstream targets during the development of PH remain unclear.
Methods:
The expression and biological function of Ythdf2 in PASMCs were investigated in human and experimental models of PH. Smooth muscle cell-specific Ythdf2-deficient mice were used to assess the roles of Ythdf2 in PASMCs in vivo. Proteomic analysis, m6A sequencing, and RNA immunoprecipitation analysis were used to screen for potential downstream targets.
Results:
Ythdf2 was significantly upregulated in human and rodent PH-PASMCs, and smooth muscle cell-specific Ythdf2 deficiency ameliorated PASMC proliferation, right ventricular hypertrophy, pulmonary vascular remodeling, and PH development. Higher expression of Ythdf2 promoted PASMC proliferation and PH by paradoxically stabilizing Myadm mRNA in an m6A-dependent manner. Loss of Ythdf2 decreased the expression of Myadm in PASMCs and pulmonary arteries, both in vitro and in vivo. Additionally, silencing Myadm inhibited the Ythdf2-dependent hyperproliferation of PASMCs by upregulating the cell cycle kinase inhibitor p21.
Conclusions:
We have identified a novel mechanism where the increased expression of Ythdf2 stimulates PH-PASMC proliferation through an m6A/Myadm/p21 pathway. Strategies targeting Ythdf2 in PASMCs might be useful additions to the therapeutic approach to PH.
Insights
Increased Ythdf2 promotes pulmonary hypertension (PH) by stabilizing Myadm mRNA, leading to PASMC proliferation. Targeting Ythdf2 offers a potential therapeutic strategy for PH.
Area of Science:
- Molecular Biology
- Cardiovascular Research
- Epigenetics
Background:
- N6-methyladenosine (m6A) RNA modification and its regulators are implicated in pulmonary hypertension (PH) pathogenesis.
- Ythdf2 (YTH N6-methyladenosine RNA binding protein 2) degrades m6A-modified mRNAs and is linked to PH and pulmonary artery smooth muscle cell (PASMC) proliferation.
- The specific roles of Ythdf2 in PASMCs and its downstream targets in PH development require clarification.
Purpose of the Study:
- To investigate the expression and function of Ythdf2 in PASMCs during PH.
- To identify downstream targets of Ythdf2 in PASMCs in the context of PH.
- To elucidate the molecular mechanisms by which Ythdf2 contributes to PH.
Main Methods:
- Investigated Ythdf2 expression and function in human and rodent PH-PASMCs.
- Utilized smooth muscle cell-specific Ythdf2-deficient mice for in vivo studies.
- Employed proteomic analysis, m6A sequencing, and RNA immunoprecipitation to identify downstream targets.
Main Results:
- Ythdf2 was upregulated in PH-PASMCs; its deficiency ameliorated PH development and PASMC proliferation.
- Ythdf2 stabilized Myadm mRNA in an m6A-dependent manner, promoting PASMC proliferation and PH.
- Loss of Ythdf2 decreased Myadm expression, and silencing Myadm inhibited Ythdf2-dependent PASMC hyperproliferation via p21 upregulation.
Conclusions:
- Identified a novel m6A/Myadm/p21 pathway where increased Ythdf2 drives PH-PASMC proliferation.
- Ythdf2 targeting in PASMCs presents a potential therapeutic strategy for pulmonary hypertension.
