YTHDF1 Regulates Pulmonary Hypertension through Translational Control of MAGED1

Abstract

<b>Rationale:</b> Posttranscriptional modifications are implicated in vascular remodeling of pulmonary hypertension (PH). m⁶A (N⁶-methyladenosine) is an abundant RNA modification that is involved in various biological processes. Whether m⁶A RNA modification and m⁶A effector proteins play a role in pulmonary vascular remodeling and PH has not been demonstrated.<b>Objectives:</b> To determine whether m⁶A modification and m⁶A effectors contribute to the pathogenesis of PH.<b>Methods:</b> m⁶A modification and YTHDF1 expression were measured in human and experimental PH samples. RNA immunoprecipitation analysis and m⁶A sequencing were employed to screen m⁶A-marked transcripts. Genetic approaches were employed to assess the respective roles of <i>YTHDF1</i> and <i>MAGED1</i> in PH. Primary cell isolation and cultivation were used for function analysis of pulmonary artery smooth muscle cells (PASMCs).<b>Measurements and Main Results:</b> Elevated m⁶A levels and increased YTHDF1 protein expression were found in human and rodent PH samples as well as in hypoxic PASMCs. The deletion of <i>YTHDF1</i> ameliorated PASMC proliferation, phenotype switch, and PH development both <i>in vivo</i> and <i>in vitro</i>. m⁶A RNA immunoprecipitation analysis identified <i>MAGED1</i> as an m⁶A-regulated gene in PH, and genetic ablation of MAGED1 improved vascular remodeling and hemodynamic parameters in SU5416/hypoxia mice. YTHDF1 recognized and promoted translation of <i>MAGED1</i> in an m⁶A-dependent manner that was absent in <i>METTL3</i>-deficient PASMCs. In addition, <i>MAGED1</i> silencing inhibited hypoxia-induced proliferation of PASMCs through downregulating PCNA.<b>Conclusions:</b> YTHDF1 promotes PASMC proliferation and PH by enhancing MAGED1 translation. This study identifies the m⁶A RNA modification as a novel mediator of pathological changes in PASMCs and PH.