The uptake of β-amyloid by various brain cells exhibits heterogeneity and correlates with the CD14 expression

The involvement of β-amyloid (Aβ) in the pathogenesis of Alzheimer's disease (AD) remains a contentious topic within the scientific community. For a long time, many studies have been highly interested in the topic of brain cells internalizing Aβ. Nonetheless, the precise processes and mechanisms underlying Aβ internalization by neurons, astrocytes, and microglia under AD settings have yet to be clarified. This study investigated primary neurons and glial cells cultured in vitro, as well as APP/PS1 mouse models. Laser confocal microscopy, frozen brain sections, and intraventricular injection in mice and other methods were employed to evaluate the uptake of Aβ42 monomers and oligomers (ADDL) by neurons, microglia, astrocytes. The results revealed that both microglia and neurons internalized Aβ oligomers. In the experiment, the Aβ that adhered to the cells, as visible using the laser confocal microscope, likely comprised two components: the portion that attached to the cells and the portion that was internalized by them. Contrary to prior observations, astrocytes exhibited limited in ability to internalize Aβ oligomers. The disparities in internalization across the three cell types were probably associated with CD14. This work elucidated the intricacies of several different types of cells internalization of Aβ processes and support a crucial role for CD14 in regulating Aβ internalization.