Estudo dos polimorfismos genéticos de enzimas antioxidantes nas Doenças de Alzheimer e Parkinson

Doenças neurodegenerativas é um termo genérico utilizado para um espetro de condições que afetam principalmente as células neuronais. De entre as células neuronais os neurónios têm sido os mais estudados em relação a este tipo de patologia. Os neurónios são células que constituem o sistema nervoso, e são células pós-mitóticas pelo que quando são danificadas ou morrem não há hipótese de substituição (Emerit et al. 2004). As doenças neurodegenerativas são doenças incuráveis e debilitantes que resultam na progressiva degeneração e/ou morte das células nervosas. Este facto leva a que o doente apresente alterações nos movimentos (ataxia) ou que desenvolva demência (Guyton & Hall 2006). No presente trabalho as doenças neurodegenerativas abordadas são a Doença de Alzheimer e a Doença de Parkinson. Estas patologias têm em comum o facto de serem frequentemente associadas ao processo de stress oxidativo, razão pela qual é importante avaliar a capacidade de defesa antioxidante nestas patologias, como por exemplo os parâmetros genéticos das enzimas antioxidantes como a GST. Sendo assim este trabalho tem como objetivo estudar a relação dos polimorfismos GSTM1 e GSTT1 com as Doenças de Alzheimer e Parkinson. A população em estudo é constituída por 58 indivíduos de nacionalidade Portuguesa, das quais 35 foram diagnosticados com Doença de Alzheimer e 23 com Doença de Parkinson, e a população controlo é constituída por 154 pessoas. As amostras de sangue foram colhidas em papel de filtro, de onde se extraiu o DNA através do método de Chelex® 100, posteriormente se realizou a amplificação por PCR dos genes de interesse e identificou-se o genótipo através da eletroforese em gel de agarose. Os resultados mostraram que as GSTs têm influência em ambas as patologias. Na Doença de Alzheimer é de salientar que principalmente o genótipo GSTM1 “ausente” é um fator de risco para o desenvolvimento da doença. Na Doença do Parkinson os genótipos GSTM1 e GSTT1 “ausentes” parecem ser um fator de risco para os indivíduos do sexo masculino, já nos indivíduos do sexo feminino o que se verifica é a prevalência do genótipo GSTT1 “presente”.Neurodegenerative diseases, it is a generic term for a spectrum of conditions that primarily affect neuronal cells. Among the neuronal cells, neurons have been most studied and associated with this type of pathology. Neurons are cells that constitute the nervous system, as they are post-mitotic cells, when they are damaged or die, they can’t be replaced (Emerit et al. 2004). Neurodegenerative diseases are incurable and debilitating diseases that result in the progressive degeneration and/or death of the neuronal cells. This leads to the patient presenting changes in the movements (ataxia) or to develop dementia (Guyton and Hall 2006). In the present work, the neurodegenerative diseases studied are Alzheimer's Disease and Parkinson's Disease. These disorders have in common the fact that they are often associated with oxidative stress, which is why it is important to evaluate the ability of antioxidant defense in these pathologies, such as genetic parameters of antioxidant enzymes such as GST. This work aims to study the relationship between GSTM1 and GSTT1 polymorphisms with Alzheimer's Disease and Parkinson’s Disease. The study population consists of 58 individuals of Portuguese nationality, of which 35 were diagnosed with Alzheimer's disease and 23 with Parkinson's disease, and the control population is formed by 154 people. Blood samples were collected on filter paper, from which DNA was extracted using the Chelex® 100 method, then the amplification of the genes of interest was carried out by PCR and the genotype was identified by agarose gel electrophoresis. The results showed that GSTs play an important role in both diseases. In Alzheimer's disease, it is particularly noteworthy that GSTM1 null genotype" is a risk factor for the disease development. In Parkinson's disease the GSTM1 and GSTT1 null genotypes appear to be a risk factor for men, while in the women it is noticed the prevalence of GSTT1 present genotype

Quantitative live cell imaging of a tauopathy model enables the identification of a polypharmacological drug candidate that restores physiological microtubule interaction

Tauopathies such as Alzheimer's disease are characterized by aggregation and increased phosphorylation of the microtubule-associated protein tau. Tau's pathological changes are closely linked to neurodegeneration, making tau a prime candidate for intervention. We developed an approach to monitor pathological changes of aggregation-prone human tau in living neurons. We identified 2-phenyloxazole (PHOX) derivatives as putative polypharmacological small molecules that interact with tau and modulate tau kinases. We found that PHOX15 inhibits tau aggregation, restores tau's physiological microtubule interaction, and reduces tau phosphorylation at disease-relevant sites. Molecular dynamics simulations highlight cryptic channel-like pockets crossing tau protofilaments and suggest that PHOX15 binding reduces the protofilament's ability to adopt a PHF-like conformation by modifying a key glycine triad. Our data demonstrate that live-cell imaging of a tauopathy model enables screening of compounds that modulate tau-microtubule interaction and allows identification of a promising polypharmacological drug candidate that simultaneously inhibits tau aggregation and reduces tau phosphorylation.</p