Pterostilbene mitigates experimental pulmonary arterial hypertension by inhibiting endothelial-to-mesenchymal transition.

BACKGROUND: The natural compound pterostilbene (PTE) has multiple cardiovascular protective effects. However, its effects on pulmonary arterial hypertension (PAH)-associated vascular remodeling remain to be elucidated. This study investigated the effects of PTE on monocrotaline (MCT)-induced PAH in rats in vivo and explored the underlying molecular mechanisms in human primary pulmonary arterial endothelial cells (hPAECs) in vitro. METHODS: Experimental PAH was established by subcutaneous injection of MCT (50 mg/kg) in Sprague-Dawley rats, which were then randomly divided into vehicle or PTE (15 mg/kg via gavage) treatment groups. Endothelial-to-mesenchymal transition (EndMT) was modeled in hPAECs by treating with transforming growth factor-β, tumor necrosis factor-α, and interleukin-1β in combination. RESULTS: In rats with MCT-induced PAH, administration of PTE resulted in a reduction in right ventricular systolic pressure, thereby alleviating right ventricular hypertrophy. This was accompanied by mitigation of the remodeling of pulmonary arteries. In vitro, genome-wide mRNA sequencing identified that PTE significantly downregulated the expression of high mobility group AT-hook 2 (HMGA2), a transcription factor involved in the pathogenesis of EndMT. Further, we demonstrated that PTE attenuated EndMT-related changes, including (1) reduced expression of the endothelial cell-specific markers platelet and endothelial cell adhesion molecule 1, and von Willebrand factor; (2) reduced nitric oxide production; and (3) increased expression of smooth muscle α-actin and other pro-fibrotic genes. Finally, we confirmed in vivo that PTE treatment reduced the expression of HMGA1/2 and Snai1/2 (markers of EndMT), and restored the expression of von Willebrand factor in the lungs of PAH rats. CONCLUSION: PTE mitigates MCT-induced PAH and vascular remodeling in rats, at least in part, by inhibiting HMGA-mediated EndMT, suggesting that PTE may be a useful complementary medicine in the treatment of PAH.