MiRNA-199a-5p influences pulmonary artery hypertension via downregulating Smad3

Area of Science:

• Cardiovascular Biology
• Molecular Medicine
• Pulmonary Hypertension Research

Background:

• MicroRNAs (miRNAs) are implicated in cardiovascular diseases.
• miR-199a-5p is linked to heart failure and hypertrophy but its role in pulmonary artery hypertension (PAH) is unknown.
• PAH involves complex molecular changes in pulmonary vasculature.

Purpose of the Study:

• To investigate the role and mechanism of miR-199a-5p in pulmonary artery hypertension (PAH).
• To explore miR-199a-5p's potential as a therapeutic target for PAH.

Main Methods:

• PAH rat models, human pulmonary artery smooth muscle cells (HPASMCs), and endothelial cells (HPAECs) were utilized.
• miR-199a-5p expression levels were measured.
• Nitric oxide (NO) and Ca(2+) levels were assessed.
• Smad3 target gene validation was performed using dual-luciferase reporter assay.
• Smad3 overexpression and inhibition studies were conducted.

Main Results:

• miR-199a-5p expression was significantly increased in PAH models.
• Anti-miR-199a-5p treatment reduced pulmonary artery pressure and right ventricular hypertrophy, increasing NO levels.
• miR-199a-5p overexpression decreased NO and increased Ca(2+) in HPASMCs and HPAECs.
• Smad3 was identified as a direct target of miR-199a-5p.
• Smad3 modulation reversed miR-199a-5p's effects on NO and Ca(2+).
• Smad3, p-Smad3, and Smad4 were downregulated in PAH lung tissues.

Conclusions:

• miR-199a-5p acts as a regulator in pulmonary artery hypertension (PAH) by targeting Smad3.
• The miR-199a-5p/Smad3 axis influences nitric oxide and calcium signaling in pulmonary artery cells.
• Targeting miR-199a-5p presents a potential novel therapeutic strategy for PAH patients.