TiO2 nanoparticles as potential promoting agents of fibrillation of alpha-synuclein, a parkinson's disease-related protein

Background: In recent years, nanomaterials have been widely used in large quantities which make people be more frequently exposed to the chemically synthesized nanoparticles [NPs]. When NPs are introduced into an organism, they may interact with a variety of cellular components with yet largely unknown pathological consequences

Objective: It was found that NPs enhance the rate of protein fibrillation in the brain by decreasing the lag time for nucleation. Protein fibrillation is implicated in the pathogenesis of the several neurodegenerative diseases such as Parkinson's disease [PD]. alpha -Synuclein [alpha S] is natively an unfolded protein which is involved in the pathogenesis of PD. In the present study, we have analyzed the effects of three different NPs on alpha S fibrillation

Materials and Methods: alpha S protein expression and purification was done and fibrils formation was induced in the absence or presence of the three types of NPs [i. e., TiO2, SiO2, and SnO2]. The enhancement of the fluorescence emission of Thioflavin T [ThT] and transmission electron microscopy [TEM] were used to monitor the appearance and growth of the fibrils. The adsorption of alpha S monomers on the surface of NPs was investigated by tyrosine fluorescence emission measurements

Results: We found that TiO2-NPs enhances alpha S fibril formation even at a concentration of 5 micro g.mL[-]1, while the two other NPs show no significant effect on the kinetics of the fibrillation. Intrinsic tyrosine emission measurement has confirmed that the TiO2-NPs interact with alpha S fibrillation products. It is suggested that TiO2- NPs may enhance the nucleation of alpha S protein that leads to protein fibril formation

Conclusion: The fibrillization process of alpha S protein is profoundly affected by the presence of TiO2-NPs. This finding unveils the neurotoxicity potential of the TiO2-NPs, which may be considered as a probable risk for PD

[Survey about the role of appearance concern with skin cancer prevention behavior based on protection motivation theory]

Skin cancer is the most prevalent type of cancer in Yazd city. Childhood and adolescense is an important time for preventing the skin cancers. The aim of this study was to survey the role of appearance concern with skin cancer prevention behavior based on protection motivation theory. Participants in this cross- sectional study were 360 female students from 4 high schools in Yazd city. Data were gathered by using self-reporting questionnaires and were analyzed using SPSS software applying ANOVA, Pearson's correlation coefficient and linear regression tests. Using Pearson's correlation test, a statistically significant correlation between the appearance concern with perceived susceptibility, perceived severity, self-efficacy, response efficacy, protection motivation and behaviors was found [P<0.01]. The perceived susceptibility, perceived severity, self- efficacy, response efficacy, protection motivation, response costs and appearance concern could predict 0.56 of the behaviors and perceived susceptibility was the strongest predictor [beta=0.120]. Also, protection motivation could predict behavior [41%]. Results of this study support the effectiveness of protection motivation theory variables and the role of appearance concern for prediction of skin cancer prevention behaviors in participants