Nesfatin-1 ameliorates blood-brain barrier dysfunction in Alzheimer’s disease by targeting VEGF-R1 and reducing cellular senescence in brain vascular endothelial cells

Cellular senescence and associated endothelial permeability are crucial factors in the dysfunction of the blood-brain barrier (BBB) in neurodegenerative diseases, including Alzheimer's disease (AD). Nesfatin-1 (NF-1), a neuropeptide involved in regulating appetite and energy homeostasis, has not been extensively studied for its pathophysiological role in AD. In this study, we found that NF-1 treatment improved cellular senescence in brain vascular endothelial bEnd.3 cells by restoring the expression of hTERT and TERF2 against oligomerized Aβ_1-42. Additionally, NF-1 reduced p53 and p21 protein levels in bEnd.3 cells exposed to oligomerized Aβ_1-42. Notably, NF-1 reduced oligomerized Aβ_1-42-induced endothelial monolayer permeability by maintaining transendothelial electric resistance (TEER) and the levels of tight junction proteins claudin 5 and ZO-1. Furthermore, NF-1 suppressed the expression of VEGF-R1 but not VEGF-R2 in bEnd.3 cells exposed to oligomerized Aβ_1-42. Overexpression of VEGF-R1 negated the protective effects of NF-1 against oligomerized Aβ_1-42-induced cellular senescence and increased endothelial monolayer permeability, indicating the involvement of VEGF-R1 in this process. Using a transgenic (Tg APPswe/PSEN1dE9) AD mouse model, we demonstrated that NF-1 administration lowered VEGF-R1 expression in the brain cortex of AD mice. Moreover, NF-1 mitigated BBB dysfunction and enhanced the expression of claudin 5 and ZO-1 in the brains of AD mice. Our results suggest that NF-1 may be a potential therapeutic strategy for treating AD.