V-ATPase-Driven Lysosomal Activation Orchestrates MEK2-Induced Endothelial Reprogramming

Here, we use RNA-sequencing to characterize a novel strategy converting fibroblasts into endothelial-like cells through activation of lysosomal activity. Constitutively active MEK2 induces a transcriptional endothelial gene program via sustained MAPK/ERK signaling, leading to enhanced vacuolar ATPase (V-ATPase) activity, lysosomal acidification, extracellular matrix degradation, and angiogenic behavior.

Transcriptomic profiling reveals that V-ATPase inhibition impairs induction of endothelial gene expression, whereas pharmacologic V-ATPase activation with EN6 recapitulates key transcriptional features of reprogramming and promotes nuclear translocation of TFEB, a master lysosomal regulator. Consistently, TFEB overexpression, particularly a phospho-deficient mutant, boosts lysosomal gene expression and enhances the endothelial transcriptional signature.