Importance of extracellular vesicle secretion at the blood-cerebrospinal fluid interface in the pathogenesis of Alzheimer's disease

Increasing evidence indicates that extracellular vesicles (EVs) play an important role in the pathogenesis of Alzheimer's disease (AD). We previously reported that the blood-cerebrospinal fluid (CSF) interface, formed by the choroid plexus epithelial (CPE) cells, releases an increased amount of EVs into the CSF in response to peripheral inflammation. Here, we studied the importance of CP-mediated EV release in AD pathogenesis. We observed increased EV levels in the CSF of young transgenic APP/PS1 mice which correlated with high amyloid beta (A beta) CSF levels at this age. The intracerebroventricular (icv) injection of A beta oligomers (A beta O) in wild-type mice revealed a significant increase of EVs in the CSF, signifying that the presence of CSF-A beta O is sufficient to induce increased EV secretion. Using in vivo, in vitro and ex vivo approaches, we identified the CP as a major source of the CSF-EVs. Interestingly, A beta O-induced, CP-derived EVs induced pro-inflammatory effects in mixed cortical cultures. Proteome analysis of these EVs revealed the presence of several pro-inflammatory proteins, including the complement protein C3. Strikingly, inhibition of EV production using GW4869 resulted in protection against acute A beta O-induced cognitive decline. Further research into the underlying mechanisms of this EV secretion might open up novel therapeutic strategies to impact the pathogenesis and progression of AD.

Automated summary

Increasing evidence suggests that extracellular vesicles (EVs) are important in the pathogenesis of Alzheimer's disease (AD), particularly through the release of EVs at the blood-cerebrospinal fluid interface. Studies in mice showed that A beta O can induce increased EV secretion, with the choroid plexus being a major source of CSF-EVs. These EVs from CP induced pro-inflammatory effects and inhibiting EV production with GW4869 protected against cognitive decline induced by A beta O.