Oxidative modifications of protein disulfide isomerase and potential roles in proteopathies

• Grant number: 19/00813-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2019
• End date: January 31, 2020
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Ohara Augusto
• Grantee: Fernanda Bortoloso Fava
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 13/07937-8 - Redoxome - Redox Processes in Biomedicine, AP.CEPID

Abstract

The protein disulfide isomerase (PDI) is a disulfide/dithiol oxidoreductase that has several essential physiological roles, including the correct folding of newly expressed proteins. It has been shown that PDI content is increased in cellular and animal models of diseases associated with protein aggregation, such as neurodegenerative diseases, and the enzyme has been considered as a protective agent against these diseases. However, PDI has been found in protein inclusions of neurodegenerative diseases, suggesting that oxidative post-translational oxidative modifications of the recruited PDI critically affect its activity as an anti-aggregating agent. Although proteomic studies have detected oxidative PDI modifications in various animal models and in patients of diseases associated with oxidative stress, little is known about the kinetics and products of PDI oxidation by biological oxidants. But such knowledge is essential to determine which oxidants may have PDI as a relevant biological target and how such oxidants modify the enzyme to render it dysfunctional and/or aggregated. Here, we will examine the effect of CO2 on the oxidation of PDI by hydrogen peroxide and peroxynitrite in vitro in continuity to previous studies. Also, we will examine the effect of these oxidants on PDI in SH-SY5YWT and SH-SY5YG93A cells, which have been employed as a cellular model of familial amyotrophic lateral sclerosis (fALS). These studies will contribute to the characterization of PDI oxidative modifications causing protein aggregation and their consequent roles in proteopathies. The project is part of CEPID Redoxoma's goals 1 (Biomolecule oxidation and function) and 2 (Thiol-based redox proteins).