In Vivo Characterization of I91T Sod2 Polymorphism of Saccharomyces cerevisiae

The Protective Effects of Protein-Enriched Fraction from Housefly (Musca domestica) against Aged-Related Brain Aging

The Musca domestica larvae are well known for its multifunctions and great nutritional value. The present study aimed at investigating the beneficial effect of Musca domestica larvae extract (Mde) against memory impairment, structural damage and oxidative stress in aged rats. Twenty-month-old rats were gavaged with Mde for 2 mo. Morris Water Maze test indicated Mde prevented aging-induced spatial learning and memory dysfunction in the aged rats. Mde supply was also found to attenuate age-associated changes of brain histology that observed by light microscopy and transmission electron microscopy. Moreover, the increase of antioxidant capacity, glutathione peroxidase (GPx) activity, superoxide dismutase (SOD) activity, as well as the decreased methane dicarboxylic aldehyde (MDA) levels, were consistent with these results. Hence, we propose that oral administration of Mde could improve memory impairment via antioxidant action, and Mde has the potential to act as an excellent food supplement or medicine for the attenuation of brain aging.

Association of arsenic-related AS3MT gene and antioxidant SOD2 gene expression in industrial workers occupationally exposed to arsenic

Increasing anthropogenic activities related to industrialization and exposure to different toxicants increases the health hazards of industrial workers. Arsenic (As) exposure induces DNA damage and generates reactive oxygen species, which may result in many disease phenotypes. Present study explores the expression variation of As 3 methyltransferase ( AS3MT) and superoxide dismutase ( SOD2) genes in blood samples of industrial workers of different industries (brick kiln, paint, welding, pesticide, and furniture) using quantitative real-time polymerase chain reaction. A total of 250 blood samples of industrial workers were collected along with age- and gender-matched controls. Relative expression of AS3MT ( p < 0.05) and SOD2 ( p < 0.01) genes was found significantly downregulated in exposed workers compared to controls. Significant low levels of AS3MT and SOD2 gene expression were observed in workers in the paint and pesticide industry compared to other industries. Similarly, reduced expression of AS3MT ( p < 0.05) and SOD2 ( p < 0.01) was observed in smokers of industrial workers compared to smokers of the control group. Workers with >10 years of exposure had less AS3MT expression compared to workers with <10 years of exposure. Additionally, a positive Spearman correlation was observed between AS3MT versus SOD2 ( r = 0.742; p < 0.0001) in industrial workers. This study suggests that decreased AS3MT and SOD2 expression levels may lead to bioaccumulation of As in the body accompanied by increased oxidative stress ultimately inducing DNA damage.

Characterization of the activity, aggregation, and toxicity of heterodimers of WT and ALS-associated mutant Sod1

Aggregation of the antioxidant enzyme Sod1 represents common factors of both familial (fALS) and sporadic cases of ALS, a fatal neurodegenerative disease. Although many ALS studies have focused on Sod1 homodimers/homomers, the investigation of Sod1 heterodimers/heteromers remains controversial and has mostly been performed with recombinant proteins in vitro, in the absence of a cellular environment. By using living cells, this study sheds light into a critical issue in the context of fALS, the high toxicity of the WT–mutant heteromeric inclusions, especially WT–A4V heteromers which accumulate both in human cells as well as in chronologically aged yeast cells. Besides the aggregation, we proposed that an inefficient heteromer response against oxidative conditions might contribute to fALS-linked mutant hSod1 toxicity.

Mutations in Cu/Zn superoxide dismutase (Sod1) have been reported in both familial and sporadic amyotrophic lateral sclerosis (ALS). In this study, we investigated the behavior of heteromeric combinations of wild-type (WT) and mutant Sod1 proteins A4V, L38V, G93A, and G93C in human cells. We showed that both WT and mutant Sod1 formed dimers and oligomers, but only mutant Sod1 accumulated in intracellular inclusions. Coexpression of WT and hSod1 mutants resulted in the formation of a larger number of intracellular inclusions per cell than that observed in cells coexpressing WT or mutant hSod1. The number of inclusions was greater in cells expressing A4V hSod1. To eliminate the contribution of endogenous Sod1, and better evaluate the effect of ALS-associated mutant Sod1 expression, we expressed human Sod1 WT and mutants in human cells knocked down for endogenous Sod1 (Sod1-KD), and in sod1Δ yeast cells. Using Sod1-KD cells we found that the WT–A4V heteromers formed higher molecular weight species compared with A4V and WT homomers. Using the yeast model, in conditions of chronological aging, we concluded that cells expressing Sod1 heterodimers showed decreased antioxidant activity, increased oxidative damage, reduced longevity, and oxidative stress-induced mutant Sod1 aggregation. In addition, we also found that ALS-associated Sod1 mutations reduced nuclear localization and, consequently, impaired the antioxidant response, suggesting this change in localization may contribute to disease in familial ALS. Overall, our study provides insight into the molecular underpinnings of ALS and may open avenues for the design of future therapeutic strategies.