Passive immunization with anti-Tau antibodies in two transgenic models: reduction of Tau pathology and delay of disease progression.
ABSTRACT The microtubule-associated protein Tau plays a critical role in the pathogenesis of Alzheimer disease and several related disorders (tauopathies). In the disease Tau aggregates and becomes hyperphosphorylated forming paired helical and straight filaments, which can further condense into higher order neurofibrillary tangles in neurons. The development of this pathology is consistently associated with progressive neuronal loss and cognitive decline. The identification of tractable therapeutic targets in this pathway has been challenging, and consequently very few clinical studies addressing Tau pathology are underway. Recent active immunization studies have raised the possibility of modulating Tau pathology by activating the immune system. Here we report for the first time on passive immunotherapy for Tau in two well established transgenic models of Tau pathogenesis. We show that peripheral administration of two antibodies against pathological Tau forms significantly reduces biochemical Tau pathology in the JNPL3 mouse model. We further demonstrate that peripheral administration of the same antibodies in the more rapidly progressive P301S tauopathy model not only reduces Tau pathology quantitated by biochemical assays and immunohistochemistry, but also significantly delays the onset of motor function decline and weight loss. This is accompanied by a reduction in neurospheroids, providing direct evidence of reduced neurodegeneration. Thus, passive immunotherapy is effective at preventing the buildup of intracellular Tau pathology, neurospheroids, and associated symptoms, although the exact mechanism remains uncertain. Tau immunotherapy should therefore be considered as a therapeutic approach for the treatment of Alzheimer disease and other tauopathies.
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ABSTRACT: Active immunization using tau phospho-peptides in tauopathy mouse models has been observed to reduce tau pathology, especially when given prior to the onset of pathology. Since tau aggregates in these models and in human tauopathies are composed of full-length tau with many post-translational modifications, and are composed of several tau isoforms in many of them, pathological tau proteins bearing all these post-translational modifications might prove to be optimal tau conformers to use as immunogens, especially in models with advanced tau pathology. To this aim, we immunized aged wild-type and mutant tau mice with preparations containing human paired helical filaments (PHF) emulsified in Alum-adjuvant. This immunization protocol with fibrillar PHF-tau was well tolerated and did not induce an inflammatory reaction in the brain or adverse effect in these aged mice. Mice immunized with four repeated injections developed anti-PHF-tau antibodies with rising titers that labeled human neurofibrillary tangles in situ. Immunized mutant tau mice had a lower density of hippocampal Gallyas-positive neurons. Brain levels of Sarkosyl-insoluble tau were also reduced in immunized mice. These results indicate that an immunization protocol using fibrillar PHF-tau proteins is an efficient and tolerated approach to reduce tau pathology in an aged tauopathy animal model.Journal of Alzheimer's disease: JAD 03/2014; 40. DOI:10.3233/JAD-132237 · 3.61 Impact Factor
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ABSTRACT: Tau aggregation occurs in neurodegenerative diseases including Alzheimer's disease and many other disorders collectively termed tauopathies. trans-cellular propagation of tau pathology, mediated by extracellular tau aggregates, may underlie pathogenesis of these conditions. P301S tau transgenic mice express mutant human tau protein and develop progressive tau pathology. Using a cell-based biosensor assay, we screened anti-tau monoclonal antibodies for their ability to block seeding activity present in P301S brain lysates. We infused three effective antibodies or controls into the lateral ventricle of P301S mice for 3 months. The antibodies markedly reduced hyperphosphorylated, aggregated, and insoluble tau. They also blocked development of tau seeding activity detected in brain lysates using the biosensor assay, reduced microglial activation, and improved cognitive deficits. These data imply a central role for extracellular tau aggregates in the development of pathology. They also suggest that immunotherapy specifically designed to block trans-cellular aggregate propagation will be a productive treatment strategy.Neuron 09/2013; 80(2). DOI:10.1016/j.neuron.2013.07.046 · 15.98 Impact Factor
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ABSTRACT: Alzheimer Disease (AD) is a neurodegenerative disorder and the most common form of dementia. Histopathologically is characterized by the presence of two major hallmarks, the intracellular neurofibrillary tangles (NFTs) and extracellular neuritic plaques (NPs) surrounded by activated astrocytes and microglia. NFTs consist of paired helical filaments of truncated tau protein that is abnormally hyperphosphorylated. The main component in the NP is the amyloid-β peptide (Aβ), a small fragment of 40-42 amino acids with a molecular weight of 4 kD. It has been proposed that the amyloid aggregates and microglia activation are able to favor the neurodegenerative process observed in AD patients. However, the role of inflammation in AD is controversial, because in early stages the inflammation could have a beneficial role in the pathology, since it has been thought that the microglia and astrocytes activated could be involved in Aβ clearance. Nevertheless the chronic activation of the microglia has been related with an increase of Aβ and possibly with tau phosphorylation. Studies in AD brains have shown an upregulation of complement molecules, pro-inflammatory cytokines, acute phase reactants and other inflammatory mediators that could contribute with the neurodegenerative process. Clinical trials and animal models with non-steroidal anti-inflammatory drugs (NSAIDs) indicate that these drugs may decrease the risk of developing AD and apparently reduce Aβ deposition. Finally, further studies are needed to determine whether treatment with anti-inflammatory strategies, may decrease the neurodegenerative process that affects these patients.Frontiers in Integrative Neuroscience 08/2013; 7:59. DOI:10.3389/fnint.2013.00059