Abstract
Persistent pulmonary hypertension of the newborn (PPHN) represents a life-threatening cardiopulmonary condition characterized by hypoxia-driven pulmonary vascular remodeling. While transcription factor EB (TFEB), a master regulator of cellular adaptation to hypoxia, has been implicated in vascular pathologies, its mechanistic role in PPHN remains undefined. This study elucidates the molecular interplay of TFEB in hypoxia-induced PPHN pathogenesis. Fetal rat models of hypoxia-induced PPHN, including untreated hypoxic models and hypoxic models treated with the TFEB inhibitor Eltrombopag (EO), as well as a hypoxia-induced human pulmonary artery endothelial cell (HPAEC) model, were established. Multimodal assessments, including histopathology, qRT-PCR, JC-1 staining, immunofluorescence, flow cytometry, and Western blotting, were employed to evaluate the effects of TFEB on mitophagy and NLRP3 inflammasome. In the hypoxia group, significant thickening of the pulmonary arterioles and right ventricular wall was observed. Immunostaining revealed a significant increase in the relative staining density of TFEB-positive, NLRP3-positive, and LC3-positive cells, alongside elevated expression of mitophagy-proteins and NLRP3 inflammasome-related proteins. TFEB inhibition downregulated the expression of PINK1, TOMM20, COX IV, P62, and LC3II/I ratio, impairing mitophagy, while upregulating eNOS, NLRP3, and GSDMD, thereby enhancing NLRP3 activation and pyroptosis. In the EO group, fetal rats exhibited more pronounced pulmonary arteriole thickening, intensified fluorescence signals for NLRP3, caspase-1, and GSDMD, reduced mitophagy-related protein expression, and further elevated NLRP3 inflammasome-related protein and GSDMD expression. TFEB exerts a protective effect in PPHN by inhibiting NLRP3 inflammasome activation through PINK1/Parkin-mediated mitophagy, highlighting TFEB's potential as a therapeutic target for hypoxia-induced PPHN.