γ-Secretase component presenilin is important for microglia β-amyloid clearance
Article first published online: 22 NOV 2010
Copyright © 2010 American Neurological Association
Annals of Neurology
Volume 69, Issue 1, pages 170–180, January 2011
How to Cite
Farfara, D., Trudler, D., Segev-Amzaleg, N., Galron, R., Stein, R. and Frenkel, D. (2011), γ-Secretase component presenilin is important for microglia β-amyloid clearance. Ann Neurol., 69: 170–180. doi: 10.1002/ana.22191
- Issue published online: 28 JAN 2011
- Article first published online: 22 NOV 2010
- Manuscript Accepted: 30 JUL 2010
- Manuscript Revised: 27 JUL 2010
- Manuscript Received: 1 FEB 2010
- Human Frontier Science Program organization
- Dana Foundation
- ISF-Legacy Heritage Biomedical Science Partnership 862/09
The cleavage of amyloid precursor protein by γ-secretase is an important aspect of the pathogenesis of Alzheimer's disease. γ-Secretase also cleaves other membrane proteins (eg, Notch), which control cell development and homeostasis. Presenilin 1 and 2 are considered important determinants of the γ-secretase catalytic site. Our aim was to investigate whether γ-secretase can be important for microglial phagocytosis of Alzheimer's disease β-amyloid.
We investigated the role of γ-secretase in microglia activity toward β-amyloid phagocytosis in cell culture using γ-secretase inhibitors and small hairpin RNA and presenilin-deficient mice.
We found that γ-secretase inhibitors impair microglial activity as measured in gene expression, protein levels, and migration ability, which resulted in a reduction of soluble β-amyloid phagocytosis. Moreover, microglia deficient in presenilin 1 and 2 showed impairment in phagocytosis of soluble β-amyloid. Dysfunction in the γ-secretase catalytic site led to an impairment in clearing insoluble β-amyloid from brain sections taken from an Alzheimer's disease mouse model when compared to microglia from wild-type mice.
We suggest for the first time, a dual role for γ-secretase in Alzheimer's disease. One role is the cleavage of the amyloid precursor protein for pathologic β-amyloid production and the other is to regulate microglia activity that is important for clearing neurotoxic β-amyloid deposits. Further studies of γ-secretase-mediated cellular pathways in microglia may provide useful insights into the development of Alzheimer's disease and other neurodegenerative diseases, providing future avenues for therapeutic intervention. ANN NEUROL 2010