The intricate relationship between brain vascular diseases and neurodegeneration has garnered increased attention in the scientific community. With an aging population, the incidence of these two conditions is likely to increase, making it imperative to understand the underlying common molecular mechanisms and unveiling novel avenues for therapy. Prompted by the observation that Aβ peptide aggregation has been implicated in the development of cerebral amyloid angiopathy (CAA) and that elevated concentrations of vascular endothelial growth factor (VEGF) in the cerebrospinal fluid (CSF) have been correlated with less cognitive decline in Alzheimer's disease (AD), we demonstrate that a small peptide (Pep9) encompassing the 10-30 sequence of VEGF exhibits significant ability to inhibit the aggregation of the Aβ1-42 peptide, as well as the formation of toxic oligomers. AFM studies confirmed this inhibitory capacity, which is also paralleled by a significant reduction of the random coil to a beta-sheet conformational transition. Further studies have shown that Pep9 protects differentiated neuroblastoma SH-SY5Y cells from Aβ toxicity, being even more effective than full-length protein in preventing amyloid-induced neuronal death. The use of a control peptide wherein two histidines are substituted with glycines (H11G and H12G) suggests a close relationship between the peptide amino acid sequence and its antiaggregating/neuroprotective activity. Overall, this study provides insight into the role of VEGF in AD and suggests that specific VEGF fragments could be beneficial in the treatment of this condition.
Keywords: Alzheimer's disease; aggregation; amyloid; neurodegeneration; peptide conformation.