Navegando por Palavras-chave "Superoxide Dismutase"

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    Cognition and biomarkers of oxidative stress in obstructive sleep apnea
    (Faculdade de Medicina / USP, 2013-04-01) Sales, Leticia Viana; Bruin, Veralice Meireles Sales de [UNIFESP]; D'Almeida, Vânia [UNIFESP]; Pompéia, Sabine [UNIFESP]; Bueno, Orlando Francisco Amodeo [UNIFESP]; Tufik, Sergio [UNIFESP]; Bittencourt, Lia Rita Azeredo [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade Federal do Ceará (UFC) Faculdade de Medicina
    OBJECTIVES: The aim of this study was to investigate neuropsychological performance and biomarkers of oxidative stress in patients with obstructive sleep apnea and the relationships between these factors. METHODS: This was an observational, cross-sectional study of 14 patients (36.0±6.5 years old) with obstructive sleep apnea and 13 controls (37.3±6.9 years old). All of the participants were clinically evaluated and underwent full-night polysomnography as well as neuropsychological tests. Blood samples were used to assay superoxide dismutase, catalase, glutathione and homocysteine, as well as vitamins E, C, B11 and B12. RESULTS: The patients performed poorly relative to the controls on several neuropsychological tests, such as the attention test and tests of long-term memory and working memory/executive function. They also had lower levels of vitamin E (p<0.006), superoxide dismutase (p<0.001) and vitamin B11 (p<0.001), as well as higher concentrations of homocysteine (p<0.02). Serum concentrations of vitamin C, catalase, glutathione and vitamin B12 were unaltered. Vitamin E levels were related to performance in the backward digit span task (F = 15.9; p = 0.002) and this correlation remained after controlling for age and body mass index (F = 6.3, p = 0.01). A relationship between superoxide dismutase concentrations and executive non-perseveration errors in the Wisconsin Card Sorting Test (F = 7.9; p = 0.01) was also observed. CONCLUSIONS: Decreased levels of antioxidants and lower performance on the neuropsychological tasks were observed in patients with obstructive sleep apnea. This study suggests that an imbalance between antioxidants and pro-oxidants may contribute to neuropsychological alterations in this patient population.
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    Papel da acetilação proteica nos mecanismos de resposta ao estresse oxidativo de Trypanosoma cruzi
    (Universidade Federal de São Paulo (UNIFESP), 2020-04-30) Moura, Leila Maria Dos Santos [UNIFESP]; Moretti, Nilmar Silvio [UNIFESP]; Universidade Federal de São Paulo
    Trypanosoma cruzi, the etiological agent of Chagas disease, faces a redox environment during its life cycle in both invertebrate and vertebrate hosts. To deal with this environment the parasite has a complex antioxidant arsenal of enzymes that relies mainly in the use of trypanothione to eliminates reactive oxygen species. Eukaryotic cells have signaling pathways regulated by post-translational modifications that allows the activation/inhibition of antioxidant enzymes, which contributes to the maintenance of intracellular homeostasis of redox environment. The regulation of human manganese superoxide dismutase (MnSOD) by acetylation is a classic example of this mechanism of regulation. MnSOD is a key enzyme in the oxidative stress response converting superoxide molecules (O2-) to hydrogen peroxide (H2O2) and molecular oxygen, and is negatively regulated by acetylation. Recently, we described the acetylome of T. cruzi epimastigote form and detected the main antioxidant enzymes of this parasite acetylated, including the mitochondrial superoxide dismutase A (TcSODA), suggesting that protein acetylation could participate in the oxidative stress response of T. cruzi. Thus, in this project we decided to investigate the role of protein acetylation in the regulation of oxidative stress response in this parasite using as model of study TcSODA. Using site-directed mutations, we characterize the lysine residue K97 responsible for regulating the activity of TcSODA; demonstrated that cell lines overexpressing the mitochondrial lysine deacetylase NAD+-dependent, TcSir2rp3, are more resistance to oxidizing agents, H2O2 and menadione. Moreover, these cell lines presented higher resistance to benznidazole (BZD) and nifurtimox (NFX), the drugs used to treatment of Chagas disease, which is preconized to kill the parasite by increasing the levels of redox molecules in the cell. This resistance to BZD and NFX is accompanied by a reduction in ROS and an increase in the activity of superoxide dismutase of these parasites. Finally, we demonstrated the interaction of TcSODA and TcSir2rp3 proteins using immunoprecipitation assays. Taken together, these results shown for the first time the involvement of protein acetylation in the maintenance of homeostatic redox state in trypanosomatids, contributing to the understanding of mechanisms used by T. cruzi to progress during the infection and opening the opportunity to explore protein acetylation as potential drug target in this parasite.