Evaluation of oxysterols and study of cholesterol aldehydes cytotoxicity in cells model for amyotrophic lateral sclerosis

• Grant number: 10/12695-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2010
• End date: April 30, 2012
• Field of knowledge: Biological Sciences - Biochemistry - Chemistry of Macromolecules
• Agreement: NSF - American Universities (Chemistry)
• Principal Investigator: Sayuri Miyamoto
• Grantee: Rafaella Mieko Araujo Kazaoka
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disorder manifested primarily in adults over the age of 50 years characterized by a progressive failure of motor neurons in the spinal cord. The etiology of the disease is not yet fully elucidated. However, it is postulated that 90-95% of cases are sporadic origin and 5-10 % of family origin. Among the familial cases, 20-25% of cases are caused by mutations in the gene encoding copper,zinc-superoxide dismutase (Cu,Zn-SOD, SOD1). The mutation results in a toxic gain of function, whose biochemical origin is still unknown. Studies in animal model containing this mutation has revealed the presence of intracellular aggregates of SOD1 and increased oxidative damage, suggesting the involvement of reactive oxygen species in this pathology. Lipids are a heterogeneous group of compounds that play a crucial role in the cell. Among them, cholesterol is an important component of cell membranes in eukaryotes. Like unsaturated lipids, cholesterol is also susceptible to oxidation by reactive species yielding a series of oxidized products collectively called oxysterols. Cholesterol oxidation mediated by singlet oxygen produces the cholesterol carboxyaldehyde (ChAld). This aldehyde has been detected in atherosclerotic plaques in LDL, heart and brains of rats. In addition, oxysterols have been related to apoptotic, necrotic and inflammatory events. Moreover, studies have shown a correlation between hypercholesterolemia and neurodegenerative diseases. This work aims to perform the detection and quantification of cholesterol and its oxysterols as possible markers of oxidative damage in ALS as well as analyzing the cytotoxicity of ChAld in human neuroblastoma cells transfected with SOD1 G93A mutant. (AU)