EFFECTS OF DIFFERENT DIETS IN A MOUSE MODEL OF NEURODEGENERATIVE DISEASE

Effects of different diets in a mouse model of neurodegeneration Abstract Tauopathies are neurodegenerative disorders characterized by the accumulation of abnormal Tau protein leading to cognitive and/or motor dysfunction; several studies suggest that dietary manipulations are increasingly viewed as possible approaches to treating neurodegenerative diseases. The mouse model chosen for this study was P301L; mice expressing P301L mutant Tau mimics features of human tauopathies and provides a model for investigating the neuropathogenesis of diseases. In this study we investigate at 7 and 15 months of age the effects of different diets (high fat-protein diet and low fat-protein diet) on P301L TG and CTR mice valuating metabolic, behavioral and cognitive activities; for the metabolic activities we analyzed survival rate, body weight gain and food and water consumption of animals. For behavioral activities we valuated mnemonic, locomotor and exploratory performances of animals; for cognitive activities we investigated the cognitive impairment (identifying agglomerates of hyperphosphorylated tau, neuronal loss, astrogliosis and oxidative damage) using immunohistochemical analysis and neuronal counts. We characterized P301L TG mouse model (trial 1-3) that replicated the impairments found in patients affected by tauophaty in a way age-gender-dependent showing in female TG mice a strong cognitive impairment strictly correlated with an increase in P-Tau, in both cerebral cortex and hippocampus, as well as astrogliosis and oxidative damage. We found an improvement of pathological conditions in TG mice administrating a low fat-protein diet in a way age-gender-dependent (trial 2-3), occurred with an increased lifespan, a reduction of food and water consumption, a reduction of aggregates of P-Tau, neuronal loss, astrogliosis and oxidative damage. We found an interaction between tauophaty and consumption of high fat-protein expressed on peripheral organs as hepatic insulin resistance and fatty accumulation in the liver, which induced nonalcoholic fatty liver disease in TG mice (trial 4). The correlation between P-Tau, insulin/IGF resistance and high fat-protein diet consumption was expressed by a condition of hepatomegaly characterized by the presence of lobular inflammatory infiltrate and deposits of collagen in liver and spleen, an increase of weight and size of liver and spleen, the highest increase of median levels of triglycerides, AST and ALT in P301L TG mice fed with high-fat protein diet in a way age-gender-dependent. In summary, we demonstrated the importance of interaction between nutrition and neurodegeneration and the role that different diets can have on the onset and development of tauophaty, obtaining an improvement of pathological conditions administrating a low fat-protein diet. Results obtained in this study suggest that P301L-Tau model could represent a valuable tool to study the role and the mechanisms through hyperphosphorylation and Tau aggregation leading to cognitive and memory impairment. Using the influence of nutrition for preventing or reducing the accumulation of hyperphosphorylated tau in this model could finally lead to the development of preventive potential treatments for tauopathies

Evidence of Presynaptic Localization and Function of the c-Jun N-Terminal Kinase

The c-Jun N-terminal kinase (JNK) is part of a stress signalling pathway strongly activated by NMDA-stimulation and involved in synaptic plasticity. Many studies have been focused on the post-synaptic mechanism of JNK action, and less is known about JNK presynaptic localization and its physiological role at this site. Here we examined whether JNK is present at the presynaptic site and its activity after presynaptic NMDA receptors stimulation. By using N-SIM Structured Super Resolution Microscopy as well as biochemical approaches, we demonstrated that presynaptic fractions contained significant amount of JNK protein and its activated form. By means of modelling design, we found that JNK, via the JBD domain, acts as a physiological effector on T-SNARE proteins; then using biochemical approaches we demonstrated the interaction between Syntaxin-1-JNK, Syntaxin-2-JNK, and Snap25-JNK. In addition, taking advance of the specific JNK inhibitor peptide, D-JNKI1, we defined JNK action on the SNARE complex formation. Finally, electrophysiological recordings confirmed the role of JNK in the presynaptic modulation of vesicle release. These data suggest that JNK-dependent phosphorylation of T-SNARE proteins may have an important functional role in synaptic plasticity

Abeta42 neurotoxicity is mediated by ongoing nucleated polymerization process rather than by discrete Abeta42 species

The identification of toxic Aβ species and/or the process of their formation is crucial for understanding the mechanism(s) of Aβ neurotoxicity in Alzheimer disease and also for the development of effective diagnostic and therapeutic interventions. To elucidate the structural basis of Aβ toxicity, we developed different procedures to isolate Aβ species of defined size and morphology distribution, and we investigated their toxicity in different cell lines and primary neurons. We observed that crude Aβ42 preparations, containing a monomeric and heterogeneous mixture of Aβ42 oligomers, were more toxic than purified monomeric, protofibrillar fractions, or fibrils. The toxicity of protofibrils was directly linked to their interactions with monomeric Aβ42 and strongly dependent on their ability to convert into amyloid fibrils. Subfractionation of protofibrils diminished their fibrillization and toxicity, whereas reintroduction of monomeric Aβ42 into purified protofibril fractions restored amyloid formation and enhanced their toxicity. Selective removal of monomeric Aβ42 from these preparations, using insulin-degrading enzyme, reversed the toxicity of Aβ42 protofibrils. Together, our findings demonstrate that Aβ42 toxicity is not linked to specific prefibrillar aggregate(s) but rather to the ability of these species to grow and undergo fibril formation, which depends on the presence of monomeric Aβ42. These findings contribute significantly to the understanding of amyloid formation and toxicity in Alzheimer disease, provide novel insight into mechanisms of Aβ protofibril toxicity, and important implications for designing anti-amyloid therapies

Taurine administration recovers motor and learning deficits in an angelman syndrome mouse model

Angelman syndrome (AS, MIM 105830) is a rare neurodevelopmental disorder affecting 1:10\ue2\u80\u9320,000 children. Patients show moderate to severe intellectual disability, ataxia and absence of speech. Studies on both post-mortem AS human brains and mouse models revealed dysfunctions in the extra synaptic gamma-aminobutyric acid (GABA) receptors implicated in the pathogenesis. Taurine is a free intracellular sulfur-containing amino acid, abundant in brain, considered an inhibiting neurotransmitter with neuroprotective properties. As taurine acts as an agonist of GABA-A receptors, we aimed at investigating whether it might ameliorate AS symptoms. Since mice weaning, we orally administered 1 g/kg/day taurine in water to Ube3a-deficient mice. To test the improvement of motor and cognitive skills, Rotarod, Novel Object Recognition and Open Field tests were assayed at 7, 14, 21 and 30 weeks, while biochemical tests and amino acid dosages were carried out, respectively, by Western-blot and high-performance liquid chromatography (HPLC) on frozen whole brains. Treatment of Ube3am\ue2\u80\u93/p+mice with taurine significantly improved motor and learning skills and restored the levels of the post-synaptic PSD-95 and pERK1/2-ERK1/2 ratio to wild type values. No side effects of taurine were observed. Our study indicates taurine administration as a potential therapy to ameliorate motor deficits and learning difficulties in AS

The c-jun N-terminal kinase plays a key role in ocular degenerative changes in a mouse model of Alzheimer disease suggesting a correlation between ocular and brain pathologies

Recently a range of ocular manifestations such as retinal and lens amyloid-beta accumulation and retinal nerve fiber layer loss have been proposed as potential biomarkers in Alzheimer disease (AD). The TgCRND8 mouse model of AD exhibits age-dependent amyloid \u3b2 (A\u3b2) oligomers accumulation and cognitive defects, amyloid plaques and hyperphosphorylated Tau deposition and inflammation. We proved the correlation between ocular pathologies and AD, observing increased levels of p-APP and p-Tau, accumulation of A\u3b2 oligomers in the retina, eye, and optic nerve. The accumulation of amyloid markers was significantly stronger in the retinal ganglion cell (RGC) layer, suggesting that RGC might be more susceptible to degeneration. We detected a thinning of the RGC layer as well as RGC death in the retina of TgCRND8 mice, by using a combination of Optical Coherence Tomography (OCT), immunofluorescence, immunohistochemistry and Western blotting techniques. We proved for the first time the key role of C-Jun N-terminal Kinase (JNK) in the ocular degeneration. In support of this, the administration of the JNK inhibitor, D-JNKI1, was able to counteract the A\u3b2 and p-Tau accumulation in the retina of TgCRND8 mice, and consequently reduce RGCs loss. These results confirm that degenerative changes in the retina/eye of AD mouse model mirrors the events observed in the brain parenchyma. Ocular changes can be detected by non-invasive imaging techniques, such as OCT, to study and test different therapeutic strategies against degenerative events associated to AD

An effector-reduced anti-β-amyloid (Aβ) antibody with unique aβ binding properties promotes neuroprotection and glial engulfment of Aβ.

Passive immunization against β-amyloid (Aβ) has become an increasingly desirable strategy as a therapeutic treatment for Alzheimer's disease (AD). However, traditional passive immunization approaches carry the risk of Fcγ receptor-mediated overactivation of microglial cells, which may contribute to an inappropriate proinflammatory response leading to vasogenic edema and cerebral microhemorrhage. Here, we describe the generation of a humanized anti-Aβ monoclonal antibody of an IgG4 isotype, known as MABT5102A (MABT). An IgG4 subclass was selected to reduce the risk of Fcγ receptor-mediated overactivation of microglia. MABT bound with high affinity to multiple forms of Aβ, protected against Aβ1-42 oligomer-induced cytotoxicity, and increased uptake of neurotoxic Aβ oligomers by microglia. Furthermore, MABT-mediated amyloid plaque removal was demonstrated using in vivo live imaging in hAPP((V717I))/PS1 transgenic mice. When compared with a human IgG1 wild-type subclass, containing the same antigen-binding variable domains and with equal binding to Aβ, MABT showed reduced activation of stress-activated p38MAPK (p38 mitogen-activated protein kinase) in microglia and induced less release of the proinflammatory cytokine TNFα. We propose that a humanized IgG4 anti-Aβ antibody that takes advantage of a unique Aβ binding profile, while also possessing reduced effector function, may provide a safer therapeutic alternative for passive immunotherapy for AD. Data from a phase I clinical trial testing MABT is consistent with this hypothesis, showing no signs of vasogenic edema, even in ApoE4 carriers

The effect of two different Individually Ventilated Cage systems on anxiety-related behaviour and welfare in two strains of laboratory mouse

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Análisis de diseño del Plan Nacional Bienal para la lucha contra la Trata y Explotación de Personas y para la Protección y Asistencia a las Victimas entre los años 2018-2020

Resumen: “La Ciencia Política debe ocuparse de los grandes problemas de la sociedad y que no debe limitarse a las cuestiones técnicas ni a recetar políticas a corto plazo, sino que puede criticar las prácticas y principios sociales y que, además, debería estar dispuesta a dar a conocer sus hallazgos de una forma accesible y a no eludir los retos que plantea recomendar políticas […]” (Marsh, D. & Stoker, G., 1995) El presente trabajo de investigación buscó caracterizar el Plan Bienal Nacional para la Lucha contra la Trata y Explotación de Personas y para la Protección y Asistencia a las Víctimas (2018-2020) mediante la metodología propuesta por Osuna (2000) en su Guía para la Evaluación de Políticas Públicas, donde el análisis se centró en el diseño del proyecto en cuestión, es decir “la evaluación que tiene como objetivo la revisión de los elementos que justifican la necesidad y forma en que se articula el programa”, analizando la racionalidad y la coherencia del mismo. El tema elegido es de interés porque involucra una problemática muy complicada que aqueja a nuestro país, no solo en materia de políticas publicas sino en todo sentido. Pero, además, se ha tenido en cuenta este Plan Bienal por ser el primero creado por el estado Argentino para saldar la deuda con las víctimas y la sociedad, pero sobre todo por estar en falta con la Ley 26.842. En relación a los resultados obtenidos en cuanto a la racionalidad del programa, se observa que, si bien se identifican las necesidades y problemáticas, es recomendable que estas estén detalladas en el programa en cuestión, lo mismo sucede con el análisis del contexto socioeconómico. La población objetivo no está cuantificada, pero si se la logra identificar. Los objetivos están formulados de manera clara, sin ambigüedades y respeta en su mayoría lo propuesto por Osuna (2000) Finalmente, para la coherencia del Plan Bienal, en el caso de la coherencia interna se identificó que los objetivos cumplen con una jerarquización y con una concordancia con la meta global del programa, pero al relacionarse con las problemáticas lo que se detectó es que, al ser problemáticas transversales al programa en cuestión, era imposible realizar una separación de los ejes y los objetivos para vincularlos puntualmente con un problema específico. Sin embargo, para la coherencia externa se notó una adecuación a normativas de orden superior y una gran articulación con otros programas en tiempo y espacio