Some transgenic (Tg) mouse (Mo) lines that carry and express a Syrian hamster (Ha) PrP gene developed scrapie 75 d after inoculation with Ha prions; non-Tg mice failed to show symptoms after greater than 500 d. Brains of these infected Tg(HaPrP) mice featured protease-resistant HaPrPSc, amyloid plaques characteristic for Ha scrapie, and 10(9) ID50 units of Ha-specific prions upon bioassay.
The beta-amyloid protein (beta/A4), derived from a larger amyloid precursor protein (APP), is the principal component of senile plaques in Alzheimer's disease.
The regulation of extracellular proteolysis by PN-II and the deposition of at least parts of the molecule in senile plaques is consistent with previous reports that implicate altered proteolysis in the pathogenesis of Alzheimer's disease.
While amyloid fibrils in SPs are composed of beta-amyloid (A beta), NFTs and SPs contain similar associated components such as ubiquitin, alpha 1-antichymotrypsin (ACT), apolipoprotein E (ApoE), heparan sulfate proteoglycans (HSPGs), and aluminum salts.
Further, since intracerebral injections of PHF tau with and without AlCl3 in rats appear uniquely capable of inducing co-deposits of a number of proteins found in authentic AD SPs and NFTs (including A beta, ubiquitin, ACT, and ApoE), we speculate that the contributions of PHF tau to plaque and tangle formation in AD may be modulated by aluminum.
In Alzheimer's disease, synuclein/NAC (non-amyloid beta component of Alzheimer's disease amyloid) proteins are found in presynaptic cholinergic nerve terminals that degenerate early in Alzheimer's disease, and they are also found closely linked to beta-amyloid fibrils in senile plaques.
In Alzheimer's disease, synuclein/NAC (non-amyloid beta component of Alzheimer's disease amyloid) proteins are found in presynaptic cholinergic nerve terminals that degenerate early in Alzheimer's disease, and they are also found closely linked to beta-amyloid fibrils in senile plaques.
A central event in Alzheimer's disease is the conformational change from normally circulating soluble amyloid beta peptides (A beta) and tau proteins into amyloid fibrils, in the form of senile plaques and neurofibrillary tangles respectively.