Atorvastatin inhibits PASMC proliferation in pulmonary hypertension via the TLR4/NF-κB/NLRP3/IL-1β pathway

Pulmonary hypertension (PH) is a progressive disorder leading to right heart failure. This study explored how atorvastatin (ATO) alleviates PH using a multidisciplinary approach. Network pharmacology, molecular docking, and dynamics analysis were employed to identify ATO targets. A PH rat model was established via monocrotaline (40 mg/kg) subcutaneous injection, and animals were divided into CT, PH, and ATO (10 mg/kg/day) groups. Hemodynamics, histopathology, and immunofluorescence were evaluated. In vitro, pulmonary arterial smooth muscle cells (PASMCs) were exposed to PDGF-BB (20 ng/ml) with or without ATO (10-8 M). Cell proliferation was measured by CCK-8 and PCNA expression, and key proteins in the TLR4/NF-κB/NLRP3/IL-1β pathway were analyzed via western blot. siRNA-NLRP3 was used to verify NLRP3's role in PASMCs proliferation. Network pharmacology identified 277 common targets, with KEGG analysis linking ATO to the NF-κB signaling pathway. Docking showed strong binding affinity between ATO and TLR4 (-6.3 kCal/mol) through non-covalent interactions with ASN464 and PHE487. In vivo, ATO reduced right ventricular systolic pressure, right ventricular hypertrophy and pulmonary artery thickening. Immunofluorescence confirmed NLRP3 co-localization with α-SMA+ PASMCs. ATO downregulated TLR4/NF-κB/NLRP3/IL-1β protein expression in PH rats' lungs and PASMCs, and suppressed PDGF-BB-induced PASMCs proliferation via the pathway inhibition. Direct knockdown of NLRP3 reduced both PDGF-BB-induced and non-PDGF-BB-induced proliferation of PASMCs, and ATO primarily inhibited PASMCs proliferation through NLRP3. These findings demonstrate that ATO directly targets TLR4 to inhibit NF-κB/NLRP3/IL-1β signaling, thereby reducing PASMCs proliferation and suppressing PH progression.