Expression of the protooncogene bcl-2 in Alzheimer's disease brain.
To investigate the role of the apopotosis-related protooncogene bcl-2 in Alzheimer's disease (AD), we compared levels of its protein product, designated Bcl-2, in AD and nondemented (ND) age-matched control neocortical samples. The 26 kD Bcl-2 protein is increased in expression by more than three-fold in AD compared to ND samples as detected by immunoblots. Immunohistochemical analyses give similar results. In AD patients Bcl-2 immunoreactivity is dense and profuse and appears to occur on reactive astrocytes, whereas Bcl-2 immunoreactivity of astrocytes in ND patients is light and sparse. Staining of both gray and white matter is observed but is most prominent in the latter. Increased expression of Bcl-2 by astrocytes may partially underlie their resistance to loss in AD. By contrast, neuronal Bcl-2 immunoreactivity is more sparse and equivocal, perhaps reflecting the vulnerability of this cell type to apoptotic mechanisms in AD. High levels of Bcl-2 in glial cells may aid in cell survival of reactive astrocytes resulting in either beneficial or deleterious effects on neuronal viability.
O'Barr
S
S
L.J. Roberts Center, Sun Health Research Institute, Sun City, AZ 85372, USA.
Schultz
J
J
Rogers
J
J
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism*; D017209:Apoptosis; D001253:Astrocytes / Q000378:metabolism; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D011518:Proto-Oncogene Proteins / Q000032:analysis*; D019253:Proto-Oncogene Proteins c-bcl-2
D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2