m⁶A Modification-mediated GRAP Regulates Vascular Remodeling in Hypoxic Pulmonary Hypertension

Area of Science:

• Molecular Biology
• RNA Epigenetics
• Cardiovascular Research

Background:

• Pulmonary arterial hypertension (PAH) involves pulmonary vascular remodeling driven by human pulmonary arterial smooth muscle cell (HPASMC) dysfunction.
• N-methyladenosine (m⁶A) is a key RNA modification, but its role in PAH pathogenesis is largely unknown.
• Investigating m⁶A's role is crucial for understanding PAH and identifying therapeutic targets.

Purpose of the Study:

• To investigate the role of m⁶A modification and its effector proteins in pulmonary vascular resistance in PAH.
• To explore the function of m⁶A-modified GRAP in HPASMC proliferation, migration, and apoptosis resistance.
• To determine the therapeutic potential of targeting GRAP in PAH.

Main Methods:

• Profiling of m⁶A concentrations in lung samples from control subjects and PAH patients.
• Bioinformatics analysis, real-time PCR, immunohistochemistry, and Western blotting to assess m⁶A effectors.
• In vitro and in vivo models to study the biological effects of m⁶A-modified GRAP, including RIP-PCR for writer/reader interactions.

Main Results:

• m⁶A-modified GRAP mRNA was upregulated in PAH lungs, mouse models, and hypoxia-stimulated HPASMCs, while GRAP mRNA and protein were downregulated.
• GRAP overexpression inhibited PAH HPASMC proliferation and invasion by suppressing the Ras/ERK signaling pathway.
• METTL14 and YTHDF2 were increased in PAH, with YTHDF2 mediating GRAP mRNA degradation, and GRAP expression negatively correlated with METTL14 and YTHDF2.

Conclusions:

• GRAP plays a significant role in regulating HPASMC behavior and is implicated in PAH development.
• m⁶A modification, particularly via YTHDF2, influences GRAP stability and contributes to PAH.
• GRAP represents a potential therapeutic target for PAH, highlighting the importance of RNA epigenetics in the disease.