Microarray analysis Equal amounts of total RNA from samples of the oviducts of each animal were used

cerning age-related plaque progression in mice, indicate that a majority of A40 builds the dense cores of plaques, and that A42 accounts for the main A components of diffuse plaques and loosely core-associated oligomers, which remain watersoluble following protein extraction. Age-related production of soluble A oligomeric assemblies We next investigated age-dependent production of soluble A oligomeric assemblies in brains of rTg9191 mice. We asked LBH589 whether rTg9191 mice produce A dimers and A 56, the two brain-derived oligomeric assemblies that have been linked to memory deficits and memory-related electrophysiological dysfunction. Under denaturing experimental conditions, we analyzed these oligomers from brain extracts of young, mid-aged, and old mice. A dimers were not detected at 12 months of age; however from 2124 months of age, dimer levels increased steeply and then plateaued. In contrast, A 56 was not detectable at any age in rTg9191 mice. A 56 similarly was absent from memory-intact TgArc6 mice, but was prominent in memory-impaired 4-month-old hAPP-J20 mice included for comparison. Therefore, rTg9191 mice produce A dimers in an age-dependent manner, but do not generate detectable levels of A 56. We also employed dot blotting to characterize A oligomers in the water-soluble fraction of brain PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19786681 extracts, under non-denaturing conditions. We used OC antibodies to examine and compare levels of soluble fibrillar oligomers in rTg9191 mice at various ages, aged Tg2576 mice, and AD patients. We found that rTg9191 mice exhibited an age-dependent increase in OC immunoreactivity. At 4 months of age, OC immunoreactivity of rTg9191 mice was no more than PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19785045 that of non-transgenic controls. When rTg9191 mice reached 21 months of age, the level of OC immunoreactivity matched that of AD patients; at 24 months of age, OC immunoreactivity further increased and was comparable to that of 21-month-old Tg2576 mice. To confirm that the OC immunoreactivity arose from A oligomers, we performed immunodepletion using an array of antibodies directed against various epitopes on A. Immunodepleting A from brains of rTg9191, Tg2576 mice, and AD patients decreased OC immunoreactivity to a level comparable to that of the non-transgenic brains, indicating that OCimmunoreactive signals come from soluble A oligomers. In parallel, we used A11 antibodies to detect soluble non-fibrillar oligomers in rTg9191 and Tg2576 mice, as well as in AD patients. We found that levels of A11 7 / 26 Characterizing a Model of -Amyloid Toxicity Fig 5. Age-related production of A proteins in water-soluble, detergent-soluble, and detergentinsoluble fractions of brain extracts from rTg9191 mice. The levels of total A38, A40, and A42 proteins in water-soluble, detergent-soluble and detergent-insoluble fractions of brain extracts of rTg9191 mice at 4, 12, 21, and 24 months of age were measured using ELISA. doi:10.1371/journal.pone.0126317.g005 immunoreactivity in rTg9191 mice at all ages were comparable to levels in non-transgenic littermates. In contrast, aged Tg2576 mice and AD patients exhibited higher A11 immunoreactivities.We investigated the effects of TTA expression on hippocampal size and brain weight. For this, we first compared body and brain weights of rTg9191 mice with their littermates carrying only the TTA 9 / 26 Characterizing a Model of -Amyloid Toxicity Fig 7. rTg9191 mice age-dependently produce soluble A oligomers immunoreactive to OC but not to A11 antibodies. Soluble OCimmunore