Activation of autophagy-lysosome function by MiT/TFE transcription factors ameliorates pulmonary endothelial injury

Acute lung injury (ALI) triggered by inhaled nanoparticles represents a growing clinical concern, yet the molecular mechanisms governing pulmonary vascular endothelial injury remain poorly defined. Here, we investigate the role of the MiT/TFE transcription factor family, the master regulators of autophagy-lysosomal biogenesis, in orchestrating endothelial adaptive responses to copper oxide nanoparticles (CuONPs). In human umbilical vein endothelial cells (HUVECs), CuONPs exposure induced lysosomal membrane permeabilization and oxidative stress, which triggered robust nuclear translocation of MiT/TFE factors, particularly TFE3. This activation drove a transcriptional program of autophagy-lysosomal biogenesis, promoting the clearance of damaged lysosomes and mitigating CuONPs-induced cell death. Notably, genetic silencing of TFE3 abrogated this adaptive response, exacerbating oxidative damage and cytotoxicity, while overexpression of TFE3 conferred significant protection. In a mouse model of intratracheal CuONPs instillation, pulmonary exposure activated the TFE3 pathway in vivo. Genetic ablation of Tfe3 in mice resulted in exacerbated pulmonary vascular barrier disruption, heightened inflammation, and aggravated lung injury. Conversely, pharmacological activation of autophagy-lysosomal biogenesis with the mTOR Inhibitor Torin1 alleviated CuONPs-induced endothelial damage and lung inflammation, recapitulating the protective effect of TFE3 signaling. Collectively, our findings identify TFE3 as a critical regulator of endothelial homeostasis against nanoparticle-induced injury, acting through the transcriptional control of autophagy-lysosomal homeostasis. Targeting this pathway may represent a novel therapeutic strategy for nanoparticle-associated ALI.