Lymphatic-specific Methyltransferase3-mediated m6A modification drives vascular patterning through prostaglandin metabolism reprogramming
Lymphangiogenesis plays a pivotal role in the pathogenesis of various vascular disorders, including ocular vascular diseases and cancers. Deregulation of N6-methyladenosine (m6A) modification has been identified as a key contributor to human diseases. However, the specific involvement of m6A modification in lymphatic remodeling remains poorly understood. In this study, we demonstrate that inflammatory stimulation and corneal sutures induce elevated levels of METTL3-mediated m6A modification. METTL3 knockdown inhibits lymphatic endothelial viability, proliferation, migration, and tube formation in vitro. METTL3 knockdown attenuates corneal sutures-induced lymphangiogenesis and intratumoral lymphangiogenesis initiated by subcutaneous grafts, consequently restraining corneal neovascularization, tumor growth, and tumor neovascularization in vivo. Mechanistically, METTL3 knockdown upregulates prostaglandin-endoperoxide synthase 2 (PTGS2) expression through an m6A-YTHDF2-dependent pathway, enhancing the synthesis of cyclopentenone prostaglandins (CyPGs). Aberrant CyPG production in lymphatic endothelial cells impairs mitochondrial oxidative phosphorylation, contributing to pathological lymphangiogenesis. Moreover, selective inhibition of METTL3 with STM2457 reduces m6A levels in lymphatic endothelial cells, effectively suppressing pathological lymphangiogenesis. This study provides compelling evidence that lymphatic-specific METTL3 plays a critical role in vascular patterning through prostaglandin metabolism reprogramming. Thus, METTL3 emerges as a promising target for treating pathological lymphangiogenesis. Overall design: Examination of transcript expression differences between HLECs with or without METTL3 gene knocked down by shRNA.