β-Amyloid Protein Induces Mitophagy-Dependent Ferroptosis Through the CD36/PINK/PARKIN Pathway Leading to Blood-Brain Barrier Destruction in Alzheimer's Disease

Abstract Background Blood-brain barrier (BBB) dysfunction may occur in the onset of Alzheimer's disease (AD). While pericytes are a vital part of the neurovascular unit and the BBB, acting as the gatekeeper of the BBB. Amyloid β (Aβ) deposition and neurofibrillary tangles in the brain are the central pathological features of AD. CD36 promotes vascular amyloid deposition and leads to vascular brain damage, neurovascular dysfunction, and cognitive deficits. However, the molecular mechanism in destroying pericytes of the BBB are still unclear. Objectives To investigate the effect of low-dose Aβ1-40 administration on pericyte outcome and BBB injury molecular mechanism. Methods We selected 6-month-old and 9-month-old APP/PS1 mice and wild-type (WT) mice of the same strain, age, and sex as controls. We assessed the BBB by PET/CT. Brain pericytes were extracted and cocultured with endothelial cells (bEnd.3) to generate an in vitro BBB model to observe the effect of Aβ1-40 on the BBB. Furthermore, we explored the intracellular degradation and related molecular mechanisms of Aβ1-40 after being engulfed in cells through CD36. Results BBB permeability and the number of pericytes decreased in APP/PS1 mice. Aβ1-40 increases the permeability of the BBB in an in vivo model and downregulates the expression of CD36, which reversed the Aβ-induced changes in BBB permeability. Aβ1-40 was phagocytized in pericytes with high expression of CD36. We observed that this molecule inhibited pericyte proliferation, caused mitochondrial damage, and increased mitophagy. Finally, we confirmed that Aβ1-40 induced pericyte mitophagy-dependent ferroptosis through the CD36/PINK1/Parkin pathway. Conclusions PDGFRβ (a marker of pericytes), CD36, and amyloid β colocalized in vitro and in vivo and that Aβ1-40 caused BBB destruction by upregulating the expression of CD36 in pericytes. The mechanism by which Aβ1-40 destroys the BBB involves induction of pericyte mitophagy-dependent ferroptosis through the CD36/PINK1/Parkin pathway.