Endothelial senescence is a critical contributor to vascular aging and age-related vasculopathies. Our previous work identified AGGF1 as a regulator of cell cycle progression and anti-inflammatory signaling. However, whether AGGF1 modulates endothelial senescence remains unclear. Here, we demonstrate that AGGF1 is downregulated in both replicative and DOX-induced senescent HUVECs. AGGF1 knockdown accelerated cellular senescence as evidenced by senescence markers, including increased SA-β-gal activity, enhanced formation of γH2AX foci, elevated IL-6 levels, and impaired proliferation, whereas AGGF1 overexpression prevented DOX- and MMC-induced senescence using adenovirus and lentivirus-mediated gene manipulation. To investigate the underlying mechanisms, we performed RNA sequencing, small-molecule drug intervention, transmission electron microscopy (TEM), and other imaging techniques in subsequent experiments. Transcriptomic and functional analyses revealed that AGGF1 transcriptionally upregulates TGFB3, which is associated with TAK1 activation and AMPK phosphorylation, ultimately inhibiting excessive mitochondrial fragmentation and suppressing cellular senescence. This signaling module reduced DRP1 expression and attenuated its activating phosphorylation at Ser616. TEM results further confirmed that AGGF1 overexpression significantly reduced mitochondrial fragmentation in cells. Additionally, this proposed association was supported by pharmacological inhibition (Takinib, Compound C) and TGFB3 knockdown, which abrogated AGGF1-mediated protection. Collectively, we identified that AGGF1 is critical for regulating a proposed TGFB3-TAK1-AMPK regulatory module, which delays endothelial senescence partially through maintenance of mitochondrial morphology. Our study provides evidence that AGGF1 plays an important role in metabolic control and cellular senescence.
