RT Journal Article
SR Electronic
T1 Neuronal Clearance of Amyloid-β by Endocytic Receptor LRP1
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 19276
OP 19283
DO 10.1523/JNEUROSCI.3487-13.2013
VO 33
IS 49
A1 Takahisa Kanekiyo
A1 John R. Cirrito
A1 Chia-Chen Liu
A1 Mitsuru Shinohara
A1 Jie Li
A1 Dorothy R. Schuler
A1 Motoko Shinohara
A1 David M. Holtzman
A1 Guojun Bu
YR 2013
UL http://www.jneurosci.org/content/33/49/19276.abstract
AB Alzheimer's disease (AD) is the most prevalent form of dementia in the elderly population. Accumulation, aggregation, and deposition of amyloid-β (Aβ) peptides generated through proteolytic cleavage of amyloid precursor protein (APP) are likely initiating events in the pathogenesis of AD. While Aβ production is accelerated in familial AD, increasing evidence indicates that impaired clearance of Aβ is responsible for late-onset AD. Because Aβ is mainly generated in neurons, these cells are predicted to have the highest risk of encountering Aβ among all cell types in the brain. However, it is still unclear whether they are also involved in Aβ clearance. Here we show that receptor-mediated endocytosis in neurons by the low-density lipoprotein receptor-related protein 1 (LRP1) plays a critical role in brain Aβ clearance. LRP1 is known to be an endocytic receptor for multiple ligands including Aβ. Conditional knock-out of Lrp1 in mouse forebrain neurons leads to increased brain Aβ levels and exacerbated amyloid plaque deposition selectively in the cortex of amyloid model APP/PS1 mice without affecting Aβ production. In vivo microdialysis studies demonstrated that Aβ clearance in brain interstitial fluid is impaired in neuronal Lrp1 knock-out mice. Because the neuronal LRP1-deletion did not affect the mRNA levels of major Aβ degrading enzymes, neprilysin and insulin-degrading enzyme, the disturbed Aβ clearance is likely due to the suppression of LRP1-mediated neuronal Aβ uptake and degradation. Together, our results demonstrate that LRP1 plays an important role in receptor-mediated clearance of Aβ and indicate that neurons not only produce but also clear Aβ.