Although the risk factor for apolipoprotein E (apoE) polymorphism in Alzheimer's disease (AD) has been well described, the role that apoE plays in other neurodegenerative diseases, including Pick's disease, is not well established. To examine a possible role of apoE in Pick's disease, an immunohistochemical analysis was performed utilizing a novel site-directed antibody that is specific for an amino-terminal fragment of apoE. Application of this antibody, termed the amino-terminal apoE cleavage fragment (nApoECF) antibody, consistently labeled Pick bodies within area CA1 of the hippocampus in 4 of the 5 cases examined. Co-localization of the nApoECF antibody with PHF-1, a general marker for Pick bodies, as well as with an antibody to caspase-cleaved tau (TauC3) was evident within the hippocampus. While staining of the nApoECF antibody was robust in area CA1, little co-localization with PHF-1 in Pick bodies within the dentate gyrus was observed. A quantitative analysis indicated that approximately 86% of the Pick bodies identified in area CA1 labeled with the nApoECF antibody. The presence of truncated apoE within Pick bodies suggests a broader role of apoE beyond AD and raises the question as to whether this protein contributes to pathogenesis associated with Pick's disease.
This document was originally published by PLOS in PLOS ONE. This work is provided under a Creative Commons Attribution 4.0 License. Details regarding the use of this work can be found at: http://creativecommons.org/licenses/by/4.0/. DOI: 10.1371/journal.pone.0080180
Rohn, Troy T.; Day, Ryan J.; Catlin, Lindsey W.; Brown, Raquel J.; Rajic, Alexander J.; and Poon, Wayne W.. (2013). "Immunolocalization of an Amino-Terminal Fragment of Apolipoprotein E in the Pick's Disease Brain". PLOS ONE, 8(12), e80180-1 - e80180-7. http://dx.doi.org/10.1371/journal.pone.0080180