Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8259053 | Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease | 2016 | 50 Pages |
Abstract
Mounting evidence suggests that astrocyte activation, found in most forms of neural injury and disease, is linked to the hyperactivation of the protein phosphatase calcineurin. In many tissues and cell types, calcineurin hyperactivity is the direct result of limited proteolysis. However, little is known about the proteolytic status of calcineurin in activated astrocytes. Here, we developed a polyclonal antibody to a high activity calcineurin proteolytic fragment in the 45-48Â kDa range (ÎCN) for use in immunohistochemical applications. When applied to postmortem human brain sections, the ÎCN antibody intensely labeled cell clusters in close juxtaposition to amyloid deposits and microinfarcts. Many of these cells exhibited clear activated astrocyte morphology. The expression of ÎCN in astrocytes near areas of pathology was further confirmed using confocal microscopy. Multiple NeuN-positive cells, particularly those within microinfarct core regions, also labeled positively for ÎCN. This observation suggests that calcineurin proteolysis can also occur within damaged or dying neurons, as reported in other studies. When a similar ÎCN fragment was selectively expressed in hippocampal astrocytes of intact rats (using adeno-associated virus), we observed a significant reduction in the strength of CA3-CA1 excitatory synapses, indicating that the hyperactivation of astrocytic calcineurin is sufficient for disrupting synaptic function. Together, these results suggest that proteolytic activation of calcineurin in activated astrocytes may be a central mechanism for driving and/or exacerbating neural dysfunction during neurodegenerative disease and injury.
Keywords
VCIDDABCA1GFAPcornus ammonis 1AβNeuN3,3′-diaminobenzidineC-terminusH&EN-terminusAstrocytesAmino-terminusImmunohistochemistryIHCBeta-amyloidAlzheimer's diseaseautoinhibitory domainCNSCAMcentral nervous systemHematoxylin & EosinProteolysisGlial fibrillary acidic proteincarboxy-terminusCalmodulinCalcineurinAID
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Authors
Melanie M. Pleiss, Pradoldej Sompol, Susan D. Kraner, Hafiz Mohmmad Abdul, Jennifer L. Furman, Rodney P. Guttmann, Donna M. Wilcock, Peter T. Nelson, Christopher M. Norris,