Oxidative Stress and Amyloid Toxicity: Insights From Yeast

Abstract

Alzheimer's disease is the most common neurodegenerative disorder. One of the factors that promotes neurodegeneration is the accumulation of senile plaques formed by Aβ peptide. In this paper, it was analyzed that if oxidative stress is cause or consequence of amyloid cascade and the role of antioxidant defense system in this process, using S. cerevisiae (with a multicopy plasmid containing the Aβ1-42 sequence) as experimental model. Cells grown on glycerol were more tolerant than when grown on glucose, strengthening the role of the antioxidant defense system against Aβ accumulation. Antioxidant defense deficiency did not change the pattern of amyloid aggregation. On the other hand, the presence of Aβ increased the level of intracellular oxidation and induced the activity of catalase, superoxide dismutase, and aconitase. Peroxissomal catalase deficient cells (Δcta1), were more sensitive to Aβ toxicity than the wild type strain, while mitochondrial superoxide dismutase (Sod2) deficient cells displayed the highest frequency of petites. Besides, Aβ alters the oxygen consumption and the activity of complex III and IV. Taken together, our results point out that the Aβ toxicity mechanism involves an oxidative stress induction by increasing ROS production into the mitochondria, where Cta1 and Sod2 play a crucial role in the regulation of the redox balance. J. Cell. Biochem. 118: 1442-1452, 2017. © 2016 Wiley Periodicals, Inc.

Correlation between Antibacterial Activity and Free-Radical Scavenging: In-Vitro Evaluation of Polar/Non-Polar Extracts from 25 Plants

“…Oxidative stress is produced by the presence of unnecessary free radicals that are not neutralized by the antioxidant systems. It plays a vital pathological role in many chronic diseases and metabolic disorders, such as cancer [12,16], diabetes [17], cardiovascular disease [18], arthritis [19], ulcerative colitis [20], neural disorders [21], Alzheimer's disease [22], Parkinson's disease [23], cirrhosis [24], and aging [21]. Strengthening the antioxidant systems of the body by introducing antioxidants from outside sources can help eliminate excessive free radicals that cause oxidative stress, which impedes the progress of many oxidative stress-linked diseases.…”

Nicotinamide Reduces Amyloid Precursor Protein and Presenilin 1 in Brain Tissues of Amyloid Beta-Tail Vein Injected Mice

“…Excessive soluble and aggregated Aβ peptides and hyper-phosphorylation of tau protein stimulate plaque formation and structural/functional alterations of neurons in brain [4]. These deleterious alterations are reported to be accompanied by increased oxidative stress as well as pro-inflammatory response [56]. …”

The second International Symposium on Fungal Stress: ISFUS

“…Throughout the world, leading causes of death are agerelated diseases, such as cancer and neurodegenerative diseases. Her presentation highlighted the value of the yeast S. cerevisiae as a model to investigate the oxidative stress response and its potential impact on aging and age-related diseases (Brasil et al, 2013;França et al, 2017). Diego Bonatto's topic was the delicate balance between hybrid genomes and brewery stresses in lager yeasts.…”