HIF-2α-mediated PLVAP suppression in gCap drives immune infiltration in chronic hypoxia-induced pulmonary edema

Chronic hypoxia-induced pulmonary edema (CHPE) constitutes a life-threatening disorder characterized by alveolar-capillary barrier disruption and excessive pulmonary inflammatory infiltration. Plasmalemma vesicle-associated protein (PLVAP) is essential for maintaining endothelial integrity, yet its cell-specific regulation and pathological contributions in CHPE remain incompletely defined.

We established a CHPE mouse model and employed single-cell RNA sequencing (scRNA-seq) to profile hypoxia-induced remodeling of the pulmonary microenvironment. In vivo histological validation and in vitro functional assays using human pulmonary microvascular endothelial cells (HPMECs) were further applied to elucidate the underlying mechanisms and evaluate targeted interventions. Additionally, chromatin immunoprecipitation (ChIP) assay and dual-luciferase reporter assays were employed to investigate transcriptional regulation of PLVAP by HIF-2α.

ScRNA-seq analysis revealed specific suppression of Plvap expression within general capillary endothelial cells (gCaps) under chronic hypoxia, accompanied by severe alveolar-capillary barrier disruption. Homeostatic Plvap⁺ gCaps were substantially replaced by a Plvap^- subpopulation, which drove myeloid cell infiltration via the chemokine signaling axes and extracellular matrix adhesion pathways. Mechanistically, despite compensatory VEGFA elevation under hypoxia, hypoxia-activated HIF-2α directly occupied the PLVAP promoter to repress its transcription, effectively overriding VEGFA-mediated pro-angiogenic signals. Functionally, PLVAP overexpression successfully rescued hypoxia-induced junctional fragmentation, restored trans-endothelial electrical resistance, and mitigated endothelial hyperpermeability in HPMECs.

Our study defines the HIF-2α-PLVAP axis as a gCap-specific regulatory mechanism governing endothelial barrier integrity and inflammatory modulation under chronic hypoxia. These findings reframe the pulmonary endothelium from a passive injury target to an active driver of CHPE pathogenesis, providing a mechanistic proof-of-concept for PLVAP restoration as a potential therapeutic strategy.