An excellent study supporting the mitosis failure hypothesis. We have shown previously using Affymetrix gene chips that Aβ treatment and P301L tau expression in an Alzheimer disease tissue culture model act synergistically to promote aberrant cell cycle re-entry (Hoerndli et al., 2007). Together this indicates a role for both tau and Aβ in neuronal cell cycle re-entry in AD.
REAGENTS/MATERIAL: Immunohistochemistry: rabbit anti-cyclin A2, C-terminal domain (Abcam);
monoclonal mouse anti-cyclin D
(ab 31450, discontinued) (Abcam) was raised and used as a marker of cell cycle antigens;
monoclonal mouse anti-neuronal-specific nuclear protein/NeuN (A60) (Millipore) was used as a neuronal-specific marker. Western Blotting: rabbit anti-APP-CT20/0443 (Calbiochem);
monoclonal mouse anti-Aβ oligomers (NU1)
and monoclonal mouse anti-Aβ oligomers (NU2) (gifts of W. L. Kline and M. P Lambert, Northwestern University, Evanston, IL);
monoclonal mouse anti-human-Aβ (6E10) (Covance Research Products).
The higher molecular weight oligomers were also recognized by oligomer-specific antibodies NU1 and NU2 (data not shown). Immunocytochemistry of cells: monoclonal mouse anti-Map2 (HM-2) (Sigma-Aldrich)
and monoclonal rat anti-BrdU (BU-1/75) (Abcam). Protein Levels: We examined the levels of cell cycle proteins in brain sections of
adult B6-R1.40 transgenic mice at a variety of ages by immunohistochemistry, coimmunostaining with the neuronal marker NeuN and cyclin A,
as well as additional cell cycle proteins including cyclin D and proliferating cell nuclear antigen (data not shown). To determine whether
soluble Aβ species are capable of inducing neuronal CCEs, we treated primary cortical neurons with
varying concentrations of either monomeric or oligomeric preparations of Aβ as well as vehicle in the presence of BrdU for 24 h.
The cultures were then fixed and coimmunostained with antibodies to Map2 and BrdU.