Innate phagocytosis by peripheral blood monocytes is altered in Alzheimer's disease

2016-09

Gu, Ben J

Huang, Xin

Ou, Amber

Rembach, Alan

Fowler, Christopher J

Avula, Pavan K

Horton, Adam

Doecke, James D

Villemagne, Victor L

Macaulay, S Lance

Maruff, Paul

Fletcher, Erica L

Guymer, Robyn

Wiley, James S

Masters, Colin L

The Australian Imaging, Biomarkers and Lifestyle (AIBL) Study

ATP

Alzheimer’s disease

Copaxone (glatiramer acetate)

P2X7

Phagocytosis

Journal Article

10.1007/s00401-016-1596-3

Sporadic Alzheimer's disease (AD) is characterised by the deposition and accumulation of specific protein aggregates. Failure of clearance could underlie this process, and recent genetic association studies point towards involvement of the phagocytosis and autophagy pathways. We developed a real-time tri-color flow cytometry method to quantitate the phagocytic function of human peripheral blood monocyte subsets including non-classic CD14(dim)CD16(+), intermediate CD14(+)CD16(+) and classic CD14(+)CD16(-) monocytes. Using this method, we have measured the phagocytic ability of fresh monocytes in a study of preclinical, prodromal and clinical AD, matched with cognitively normal healthy control subjects. Basal levels of phagocytosis in all three subsets of monocytes were similar between healthy controls and AD patients, while a significant increase of basal phagocytosis was found in subjects with high Aβ-amyloid burden as assessed by PET scans. Pre-treating cells with Copaxone (CPX, to stimulate phagocytosis) or ATP (an inhibitor of P2X7-mediated phagocytosis) showed a differential response depending on clinical or Aβ-burden status, indicating a relative functional deficit. Overall the results are consistent with a perturbation of basal and stimulated innate phagocytosis in sporadic AD.

link

Acta Neuropathologica 2016; 132(3): 377-89

Acta Neuropathologica