Amyloid-β1-42 oligomers compromise oligodendrocyte precursor cells and disrupt blood-brain barrier integrity in vitro.

Amyloid-β (Aβ), particularly the aggregation-prone Aβ1-42, plays a central role in Alzheimer's disease (AD). While its neuronal toxicity is well known, effects on glial and vascular cells remain unclear. To investigate how Aβ1-42 oligomers affect oligodendrocyte precursor cells (OPCs), pericytes (PCs), and endothelial cells (ECs), and how these effects contribute to blood-brain barrier (BBB) dysfunction. In vitro assays were used to assess cell viability and BBB integrity following Aβ exposure. Transcriptomic profiling was performed on Aβ1-42-treated OPCs. Transendothelial electrical resistance (TEER) was used to measure barrier function. Aβ1-42, but not Aβ1-40, induced cytotoxicity in OPCs and PCs. ECs showed impaired barrier function without cell death. Aβ1-42-treated OPCs upregulated pro-inflammatory genes (Mmp9, Il1b) and downregulated genes related to cell cycle and growth signaling. Conditioned media from Aβ-exposed OPCs and PCs reduced TEER in ECs, indicating paracrine-mediated BBB disruption. These findings demonstrate that Aβ1-42 oligomers impair BBB integrity under in vitro conditions through both direct and non-cell autonomous mechanisms. Further in vivo studies are warranted to validate the relevance of these mechanisms in AD pathogenesis.