Abstract Fri106: UBE2L3 inhibits angiogenesis by activating mitochondrial autophagy in endothelial cells

This study explores the effects of UBE2L3 on human umbilical vein endothelial cells (HUVECs). UBE2L3, an E2 ubiquitin-conjugating enzyme, was overexpressed (OE) and knocked down (KD) in HUVECs using adenoviruses. Proliferation was assessed by EdU incorporation, migration by scratch assay, invasion by Transwell assay, and angiogenesis by tube formation. Mitochondrial function was evaluated via ROS levels, mitochondrial morphology using Mito-tracker, and apoptosis via TUNEL assay. Western blot and qRT-PCR analyzed mitochondrial-related proteins. Results show UBE2L3-OE increased ROS and apoptosis, while UBE2L3-KD had the opposite effects. UBE2L3-OE increased mitochondrial fragmentation, whereas UBE2L3-KD reduced it. UBE2L3-KD upregulated MFN1 and MFN2, promoting mitochondrial fusion. Conversely, UBE2L3-OE increased MFN1 but decreased MFN2, leading to mitochondrial dysfunction. Autophagy markers LC3, p62, and Beclin1 were also regulated by UBE2L3. UBE2L3-OE increased LC3-II/LC3-I ratio and Beclin1 but accumulated p62, indicating impaired autophagy. UBE2L3-KD decreased LC3-II/LC3-I ratio and Beclin1 while reducing p62, suggesting efficient autophagy. In conclusion, UBE2L3 significantly impacts HUVECs' mitochondrial function and autophagy. UBE2L3-OE impairs mitochondrial function and promotes apoptosis, while UBE2L3-KD protects mitochondrial function. These findings highlight UBE2L3's role in endothelial cell function and suggest it as a potential therapeutic target for cardiovascular diseases. Future work should further investigate the detailed mechanisms and in vivo effects of UBE2L3.