title: Epigenetic changes in Alzheimer's disease: decrements in DNA methylation.
abstract: DNA methylation is a vital component of the epigenetic machinery that orchestrates changes in multiple genes and helps regulate gene expression in all known vertebrates. We evaluated immunoreactivity for two markers of DNA methylation and eight methylation maintenance factors in entorhinal cortex layer II, a region exhibiting substantial Alzheimer's disease (AD) pathology in which expression changes have been reported for a wide variety of genes. We show, for the first time, neuronal immunoreactivity for all 10 of the epigenetic markers and factors, with highly significant decrements in AD cases. These decrements were particularly marked in PHF1/PS396 immunoreactive, neurofibrillary tangle-bearing neurons. In addition, two of the DNA methylation maintenance factors, DNMT1 and MBD2, have been reported also to interact with ribosomal RNAs and ribosome synthesis. Consistent with these findings, DNMT1 and MBD2, as well as p66α, exhibited punctate cytoplasmic immunoreactivity that co-localized with the ribosome markers RPL26 and 5.8s rRNA in ND neurons. By contrast, AD neurons generally lacked such staining, and there was a qualitative decrease in RPL26 and 5.8s rRNA immunoreactivity. Collectively, these findings suggest epigenetic dysfunction in AD-vulnerable neurons.
authors.affiliation: L.J. Roberts Center for Alzheimer's Research, Sun Health Research Institute, P.O. Box 1278, Sun City, AZ 85372, USA.
authors.forename: Diego
authors.initials: D
authors.lastname: Mastroeni
authors.forename: Andrew
authors.initials: A
authors.lastname: Grover
authors.forename: Elaine
authors.initials: E
authors.lastname: Delvaux
authors.forename: Charisse
authors.initials: C
authors.lastname: Whiteside
authors.forename: Paul D
authors.initials: PD
authors.lastname: Coleman
authors.forename: Joseph
authors.initials: J
authors.lastname: Rogers
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D019175:DNA Methylation / Q000235:genetics*; D015536:Down-Regulation / Q000235:genetics; D044127:Epigenesis, Genetic / Q000235:genetics*; D005260:Female; D005819:Genetic Markers; D042822:Genomic Instability / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000378:metabolism / Q000473:pathology
chemical_list: D005819:Genetic Markers