Tuesday, June 30, 2015

PRION2015 Alzheimer’s disease

PRION2015 Alzheimer’s disease


*** P.34: Preliminary study of Alzheimer’s disease transmission to bank vole


Guido Di Donato1, Geraldina Riccardi1, Claudia D’Agostino1, Flavio Torriani1, Maurizio Pocchiari2, Romolo Nonno1, Umberto Agrimi1, and Michele Angelo Di Bari1


1Department of Food Safety and Veterinary Public Health Istituto Superiore di Sanit a, Rome, Italy; 2Department of Cellular Biology and Neuroscience; Istituto Superiore di Sanit a, Rome, Italy


Extensive experimental findings indicate that prion-like mechanisms underly the pathogenesis of Alzheimer disease (AD). Transgenic mice have been pivotal for investigating prionlike mechanisms in AD, still these models have not been able so far to recapitulate the complex clinical-pathological features of AD. Here we aimed at investigating the potential of bank vole, a wild-type rodent highly susceptible to prions, in reproducing AD pathology upon experimental inoculation.


Voles were intracerebrally inoculated with brain homogenate from a familial AD patient. Animals were examined for the appearance of neurological signs until the end of experiment (800 d post-inoculation, d.p.i.). Brains were studied by immunohistochemistry for pTau Prion 2015 Poster Abstracts S29 (with AT180 and PHF-1 antibodies) and b-amyloid (4G8).


Voles didn’t show an overt clinical signs, still most of them (11/16) were found pTau positive when culled for intercurrent disease or at the end of experiment. Interestingly, voles culled as early as 125 d.p.i. already showed pTau aggregates. Deposition of pTau was similar in all voles and was characterized by neuropil threads and coiled bodies in the alveus, and by rare neurofibrillary tangles in gray matter. Conversely, b-amyloid deposition was rather rare (2/16). Nonetheless, a single vole showed the contemporaneous presence of pTau in the alveus and a few Ab plaque-like deposits in the subiculum. Uninfected age-matched voles were negative for pTau and Ab.


*** These findings corroborate and extend previous evidences on the transmissibility of pTau and Ab aggregation. Furthermore, the observation of a vole with contemporaneous propagation of pTau and Ab is intriguing and deserves further studies.




P.155: Quantitative real-time analysis of disease specific tau amyloid seeding activity


Davin Henderson and Edward Hoover Prion Research Center; College of Veterinary Medicine and Biomedical Sciences; Colorado State University; Fort Collins, CO USA


A leading hypothesis for the cause of neurodegenerative diseases is the templated misfolding of cellular proteins to an amyloid state. Spongiform encephalopathies were the first diseases discovered to be caused by a misfolded amyloid-rich protein. It is now recognized that the major human neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and chronic traumatic encephalopathy (CTE), also are associated with amyloid formation. Moreover, AD and PD amyloids have been shown competent to transmit disease in experimental animal models, suggesting shared mechanisms with traditional prion diseases. Sensitive detection of prion disease has been advanced by in vitro amplification of low levels of disease specific amyloid seeds, e.g. serial protein misfolding amplification (sPMCA), amyloid seeding (ASA) and real-time quaking induced conversion (RT-QuIC), thereby replicating the disease process in vitro. In addition, measurement of the amyloid formation rate can estimate the level of disease-associated seed by using methods analogous to quantitative polymerase chain reaction (qPCR). In the present work, we apply these principles to show that seeding activity of in vitro generated amyloid tau and AD brain amyloid tau can be readily detected and quantitated.




P.83: Gerstmann-Str€aussler-Scheinker disease with F198S mutation: Selective propagation of PrPSc and pTau upon inoculation in bank vole


Michele Angelo Di Bari1, Romolo Nonno1, Laura Pirisinu1, Claudia D’Agostino1, Geraldina Riccardi1, Guido Di Donato1, Paolo Frassanito1, Bernardino Ghetti2, Pierluigi Gambetti3, and Umberto Agrimi1


1Department of Veterinary Public Health and Food Safety; Istituto Superiore di Sanit a; Rome, Italy;


2Indiana University-Purdue University Indianapolis; Department of Pathology and Laboratory Medicine; Indianapolis, IN USA; 3Case Western Reserve University; Cleveland, OH USA


Gerstmann-Str€aussler-Scheinker disease with F198S mutation (GSS-F198S) is characterized by the presence of PrP amyloid plaques as well as neurofibrillary tangles with abnormally-phosphorylated tau protein (pTau) in the brain. The relationship between tau protein and PrP in the pathogenesis of GSS-F198S is unknown. In a previous study, we inoculated intracerebrally 2 GSS-F198S cases in 2 lines of voles carrying either methionine (Bv109M) or isoleucine (Bv109I) at codon 109 of PrP. GSS-F198S transmitted rather efficiently to Bv109I, but not to Bv109M.


Here we investigated the presence of pTau, as assessed by immunohistochemistry with anti-pTau antibodies AT180 and PHF-1, in the same voles previously inoculated with GSSF198S. Among these voles, most Bv109I showed clinical signs after short survival times (»150 d.p.i.) and were positive for PrPSc. The remaining Bv109I and all Bv109M survived for longer times without showing prion-related pathology or detectable PrPSc. All Bv109I which were previously found PrPSc-positive,


S54 Prion 2015 Poster Abstracts


were immunonegative for pTau deposition. In contrast, pTau deposition was detected in 16/20 voles culled without clinical signs after long survival times (225–804 d.p.i.). pTau deposition was characterized by neuropil threads and coiled bodies in the alveus, and was similar in all voles analyzed.


These findings highlight that pTau from GSS-F198S can propagate in voles. Importantly, pTau propagation was independent from PrPSc, as pTau was only found in PrPSc-negative voles surviving longer than 225 d.p.i. Thus, selective transmission of PrPSc and pTau proteinopathies from GSS-F198S can be accomplished by experimental transmission in voles.






I3 Aβ Strains and Alzheimer’s Disease


Lary Walker Emory University, Atlanta, GA, USA


An essential early event in the development of Alzheimer’s disease is the misfolding and aggregation of Aβ. Enigmatically, despite the extensive deposition of human-sequence Aβ in the aging brain, nonhuman primates do not develop the full pathologic or cognitive phenotype of Alzheimer’s disease, which appears to be unique to humans. In addition, some humans with marked Aβ accumulation in the brain retain their cognitive abilities, raising the question of whether the pathogenicity of Aβ is linked to the molecular features of the misfolded protein. I will present evidence for strain-like molecular differences in aggregated Aβ between humans and nonhuman primates, and among end-stage Alzheimer patients. I will also discuss a case of Alzheimer’s disease with atypical Aβ deposition to illustrate heterogeneity in the molecular architecture of Aβ assemblies, and how this variability might influence the nature of the disease. As in the case of prion diseases, strain-like variations in the molecular architecture of Aβ could help to explain the phenotypic variability in Alzheimer’s disease, as well as the distinctively human susceptibility to the disorder.


This research was conducted in collaboration with Harry LeVine, Rebecca Rosen, Amarallys Cintron, David Lynn, Yury Chernoff, Anil Mehta and Mathias Jucker and colleagues. Supported by AG040589, RR165/OD11132, AG005119, NS077049, the CART Foundation and MetLife.




I5 Pathogenic properties of synthetically generated prions


Jiyan Ma Van Andel Research Institute, Grand Rapids, Michigan, USA


Synthetically generating prions with bacterially expressed recombinant prion protein (recPrP) strongly supports the prion hypothesis. Yet, it remains unclear whether the pathogenic properties of synthetically generated prions (rec-Prion) fully recapitulate those of naturally occurring prions. A series of analyses including intracerebral and intraperitoneal transmissions of rec-Prion in wild-type mice were performed to determine the characteristics of rec-Prion induced diseases. Results from these analyses demonstrated that the rec-Prion exhibits the same pathogenic properties with naturally occurring prions, including a titratable infectivity that can be determined by endpoint titration assays, capability of transmitting prion disease via routes other than the direct intra-cerebral inoculation, causing ultra-structural lesions that are specific to prion disease, and sharing a similar manner of visceral dissemination and neuroinvasion with naturally occurring scrapie and chronic wasting disease. These findings confirmed that the disease caused by rec-Prion in wild-type mice is bona fide prion disease or transmissible spongiform encephalopathiges, and the rec-Prion contains similar pathogenic properties as naturally occurring prions.


I6 Transmissible protein toxins in neurodegenerative disease


Jacob Ayers, David Borchelt University of Florida, Gainesville, FL, USA


Amyotrophic lateral sclerosis (ALS) is an obvious example of neurodegenerative disease that seems to spread along anatomical pathways. The spread of symptoms from the site of onset (e.g. limb) to the respiratory musculature drives the rate of disease progression. In cognitive disorders, such as Alzheimer’s disease, one can find similarly find evidence of spreading dysfunction and pathology. One mechanism to account for this spread of disease from one neural structure to another is by evoking prion-like propagation of a toxic misfolded protein from cell to cell. Recent studies in animals that model aspects of Alzheimer’s Disease, Parkinson’s Disease, and Tauopathy, have bolstered the arguments in favor of prion-like, although in most of these models the mice do not develop overt “clinical” symptoms. Recently, Jacob Ayers demonstrated that the symptoms of ALS can be transmitted from a strain of mice that expresses mutant SOD1-G93A at high levels to a second transgenic strain that expresses mutant SOD1 at low, nontoxic, levels. This model showed many prion-like features including evidence of host-adaptation (earlier and more penetrant disease upon second passage). Interestingly, homogenates from paralyzed mice expressing the G37R variant of SOD1 transmitted poorly, a finding suggestive that different SOD1 variants may exhibit strain-like properties. These “ i n d u c i b l e ” m o d e l s o f h u m a n neurodegenerative disease enable the generation of models that do not require extraordinary levels of transgene expression and provide a more precise means of initiating the disease process, advances that may translate into more predictive pre-clinical models.




P188 Transmission of amyloid pathology by peripheral administration of misfolded Aβ


Javiera Bravo-Alegria1 ,2, Rodrigo Morales2, Claudia Duran-Aniotz3, Claudio Soto2 1University of Los Andes, Santiago, Chile, 2Mitchell Center for Alzheimer’s Disease and Related Brain Disorders, Department of Neurology, University of Texas Medical School, Houston, Texas, USA, 3University of Chile, Santiago, Chile


Misfolding and aggregation of Amyloid-β (Aβ) is one of the primary events involved in the pathogenesis of Alzheimer's disease (AD). Recently, it has been proposed that Aβ aggregates can transmit and spread the pathology following a prion-like mechanism. Prions can be exogenously transmitted by many different routes of administration. In the case of Aβ, previous studies showed that intraperitoneal (i.p.) injection of seeds can accelerate cerebral amyloidosis in mouse models. However, other potential routes have not yet been studied. The goal of this work was to assess whether Aβ amyloidosis can be seeded in the brain of a transgenic mouse model of AD by peripheral administration of misfolded particles.


Young tg2576 animals (50 days old) were inoculated with a pool of brain extract coming from old Tg2576 animals (10%w/v) by different routes: i.p. (100μL), eye drops (5μL each eye, 3 times), intramuscular (i.m., 50μL), and per os (p.o., 1000μL). Animals were sacrificed at 300 days old, and brain samples were analyzed for amyloid pathology by IHC and ELISA.


The i.p., i.m., and eye drops administration of Aβ seeds significantly accelerated pathological features in tg2576. Regardless of the higher volume administered, p.o. treated animals did not show any pathological changes when compared to untreated controls. Differences in the proportion of diffuse, core and vascular deposition was observed within experimental groups. Our data show that peripheral administration of Aβ seeds could accelerate pathological changes in the brain and suggest that an orchestrated cross-talk between the brain and peripheral tissues occurs in AD.






Self-Propagative Replication of Ab Oligomers Suggests Potential Transmissibility in Alzheimer Disease


Received July 24, 2014; Accepted September 16, 2014; Published November 3, 2014



*** Singeltary comment ;




No comments: