Effect of citrus flavanones in Min6 cells under oxidative stress: Proteomic approach

• Grant number: 18/26584-2
• Support type: Scholarships abroad - Research Internship - Master's degree
• Effective date (Start): April 01, 2019
• Effective date (End): June 30, 2019
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Science
• Principal researcher: Neuza Mariko Aymoto Hassimotto
• Grantee: Sara Lima Anacleto
• Supervisor abroad: Dragan Milenkovic
• Home Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Research place: University of California, Davis (UC Davis), United States
• Associated to the scholarship: 18/03965-0 - Citrus Flavanones- mechanisms of protection of pancreatic-beta cells under oxidative stress, BP.MS

Abstract

Cholesterol is one of the trigger of the oxidative stress in the pancreatic ²-cell, generating high level of reactive oxygen species, which leads to impairment of insulin synthesis and secretion. Currently, the intake of bioactive compounds, such as citrus flavanones, which present anti-inflammatory and antioxidant activities, could reduce oxidative stress in ²-cells improving its function. In our current study, cholesterol promoted oxidative stress by increasing lipid peroxidation and hydrogen peroxide, decreasing cell viability in dose and time dependent and impairing glucose-induced insulin secretion in pancreatic ²-cell (Min6 line). These alterations and dysfunction presented in Min6 cells, due to cholesterol, suggested some metabolic alterations, impairing and decreasing insulin synthesis. However, pancreatic ²-cells under oxidative stress induced by cholesterol were protected by flavanone metabolites, mainly from the 3-(4-hydroxyphenyl) propionic acid (HPPA), and the hesperetin 7-O-glucuronide (Hsp7glc) at low concentrations (2 µM, 5 µM, and 10 µM), against oxidative stress, impaired insulin secretion, and the harmful effects induced by cholesterol, mitigating its effect, preventing oxidative stress. From the physiological point of view, both HPPA and Hsp7glc are potentially promising in the protection of pancreatic ²-cells, since plasma concentrations are similar to the concentrations tested in our assays. Considering that HPPA and Hsp7glc are the most compounds among the subclass flavanones abundant in plasma and that they had a great effect in the attenuation of oxidative stress, restoring insulin secretion, these two metabolites are important to analyze possible cellular mechanisms of action. To elucidate several pathways that cholesterol can interfere in a pancreatic ²-cell, such as the enzymatic action of complex I or also in Isl1-Pdx1 pathway, as well as pathways suppressed or upper regulated by flavanone metabolites, a proteomic approach is useful. The proteomic approach could verify possible pathways or mechanism of action of flavanone metabolites in a ²-cell treated with cholesterol, analyzing protein targets through a secretome and a cell proteome assay. The aim of this project is characterize the proteomic profile of pancreatic ²-cells under oxidative stress and identify possible targets of cellular action of the flavanone metabolites. (AU)