The role of fatty acids on hypothalamic autophagy regulation

• Grant number: 14/22726-6
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: September 20, 2015
• End date: January 19, 2016
• Field of knowledge: Biological Sciences - Biochemistry - Metabolism and Bioenergetics
• Principal Investigator: Marciane Milanski Ferreira
• Grantee: Mariana Portovedo de Oliveira Araújo
• Supervisor: Christophe Magnan
• Host Institution: Faculdade de Ciências Aplicadas (FCA). Universidade Estadual de Campinas (UNICAMP). Limeira , SP, Brazil
• Institution abroad: Université Paris Diderot - Paris 7, France
• Associated to the scholarship: 13/10911-0 - Modulation of chaperone mediated autophagy in hypothalamus of diet-induced obese mice., BP.DR

Abstract

The mediobasal hypothalamus is the primary site responsible for the balance between food intake and energy expenditure, and disruption in these neurons can contribute to the development of obesity. In experimental models, obesity is known to be associated to a low grade inflammation that appears first in the hypothalamus. In this context, the high content of saturated fatty acids in the diets is pointed as one of the main factors responsible for the development of obesity. Also, recent data have shown that autophagy, a process that regulates cellular homeostasis by degrading dysfunctional proteins and organelles, is crucial to maintain the functionality of hypothalamic neurons and obese animals have a downregulation of this pathway in hypothalamus. In this study, we aim to perform a lipidomic analysis in hypothalamic cell line (GT1-7) samples treated with palmitic acid in a dose which affects autophagy. The flux of autophagy will be determined by using an RFP-GFP-LC3-II plasmid to analyze the autophagosome formation during the fatty acid treatment. The methodological approach to study autophagy is important since autophagy involve several steps. The use of autophagy markers like LC3-II needs to be correlated with measurements of autophagy flux. The RFP-GFP-LC3 plasmid allows determining if the LC3-II dot is on non lysosome fused structures or cytosol, or if LC3 is on autolysosome. This approach allows estimating the induction of autophagy and the autophagy flux in cells. In addition, we intend to learn the technique of intracarotid lipid infusion, a more physiologically tool to study the effect of lipids in central nervous system than intrecerebroventricular treatment currently used in our laboratory. Understanding the regulation of autophagy in response to fatty acids is crucial to identify the mechanism by which the diet affects hypothalamic autophagy. (AU)