Paeoniflorin Alleviates Pulmonary Arterial Hypertension by Suppressing TRIM24-Mediated SIRT1 Ubiquitination and NLRP3 Inflammasome Activation.

This study aimed to investigate the molecular mechanism by which tripartite motif-containing 24 (TRIM24) regulates the ubiquitination of sirtuin 1 (SIRT1) and to explore the protective effect of paeoniflorin (PF) on pulmonary arterial hypertension (PAH). Bioinformatics analysis identified TRIM24 and SIRT1 as key targets of PF. A PAH rat model was established by SU5416 (Su) injection combined with chronic hypoxia (Hx). These model rats were then treated with PF and/or subjected to overexpression of TRIM24 or SIRT1. TRIM24 and SIRT1 expression were assessed by reverse transcription quantitative PCR (RT-qPCR) and immunohistochemistry. Lung vascular remodeling was evaluated by hemodynamic analysis and hematoxylin-eosin (HE) staining. Inflammatory cytokine levels (interleukin-1β, interleukin-6, tumor necrosis factor-α) in lung tissues were measured. In vitro, hypoxia-exposed human pulmonary artery endothelial cells (HPAECs) were used to evaluate PF effects on cell viability (CCK-8), migration (scratch assay), and protein expression (Western blot). Ubiquitination and protein stability assays demonstrated that TRIM24 promoted SIRT1 protein degradation. TRIM24 inhibited SIRT1-mediated autophagy, thereby activating the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome. Conversely, SIRT1 upregulation enhanced autophagy and suppressed NLRP3 activation. PF alleviated PAH and endothelial dysfunction by downregulating TRIM24 and preserving SIRT1 function. These findings reveal a novel mechanism by which PF protects against PAH via the TRIM24/SIRT1/NLRP3 axis.