Journal of Alzheimer's disease : JAD
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Among the different paradigms aimed at interfering with amyloid-β (Aβ)-related pathology, the attenuation of amyloid-β protein precursor (AβPP) processing to limit Aβ levels seems to be a promising one. Along with the development of BACE1 inhibitors, and the generation of its knock-out mice, accumulating data raise concerns regarding a total inhibition of the enzyme as it shares the processing of other substrates. ⋯ Here, we demonstrate the ability of AβPP β-site antibodies to interfere with Aβ production in vivo. Systemic antibody treatment diminished Aβ plaques, membrane-associated oligomers, and intracellular Aβ accumulation, all of which have been implicated in cellular death and synaptic loss, suggesting that this approach may be an applicable strategy for AD treatment.
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Alzheimer's disease (AD) is a neurodegenerative pathology in which amyloid-beta (Abeta) peptide accumulates in different brain areas leading to deposition of plaques and a progressive decline of cognitive functions. After a decade in which a number of transgenic (Tg) mouse models mimicking AD-like amyloid-deposition pathology have been successfully generated, few rat models have been reported that develop intracellular and extracellular Abeta accumulation, together with impairment of cognition. The generation of a Tg rat reproducing the full AD-like amyloid pathology has been elusive. ⋯ Homozygous Tg animals eventually produce extracellular Abeta deposits and, by 6 months of age, dense, thioflavine S-positive, amyloid plaques are detected, associated with glial activation and surrounding dystrophic neurites. The cognitive functions in transgenic McGill-R-Thy1-APP rats, as assessed using the Morris water maze task, were found already altered as early as at 3 months of age, when no CNS plaques are yet present. The spatial cognitive impairment becomes more prominent in older animals (13 months), where the behavioral performance of Tg rats positively correlates with the levels of soluble Abeta (trimers) measured in the cortex.
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It has been reported that conditional double knockout of presenilin-1 and presenilin-2 in forebrain of mice (dKO mice) induce symptoms most analogous to that of neurodegenerative diseases, especially Alzheimer's disease, however, there is no deposition of extra amyloid-beta (Abeta(40) or Abeta(42)) in dKO brain. In the present study, we thoroughly measured the inflammatory response in dKO mice, which is another global symptom in neurodegenerative diseases. We demonstrated that glial cells were dramatically activated from early age (3 months) in dKO brain when compared with control mice. ⋯ Antibody array and ELISA analysis indicated that cytokine and chemokine levels were also significantly increased in dKO brain. Moreover, we found that leukocytes were elevated beginning at 6 months of age, and multiple inflammatory mediators changed in dKO mice serum at 9 months, showing that the inflammatory responses gradually expanded to systemic tissue. These findings confirm that presenilins double knockout results in robust inflammatory response both in brain and in periphery and suggest that dKO mice may be useful to further understand the effects of inflammation on the pathological processes of neurodegenerative diseases.