Effects of aryl receptor activation on endothelial (dys)function

• Grant number: 16/09830-4
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: September 28, 2016
• End date: March 27, 2017
• Field of knowledge: Biological Sciences - Pharmacology - Cardiorenal Pharmacology
• Principal Investigator: Rita de Cassia Aleixo Tostes Passaglia
• Grantee: Pedro Afonso Barreto Ferreira
• Supervisor: Nikolaos Stergiopulos
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Institution abroad: École Polytechnique Fédérale de Lausanne (EPFL), Switzerland
• Associated to the scholarship: 15/11742-3 - The Role of Aryl Hydrocarbon Receptor in atherosclerotic plaque instability or vulnerability, BP.MS

Abstract

Atherosclerosis is a chronic inflammatory disease in the subendothelial layer of large- and medium-sized arteries. It is characterized by the formation of atherosclerotic plaques consisting of necrotic cores, calcified regions, accumulated modified lipids, vascular smooth muscle cells (VSMCs), endothelial cells, leukocytes, and foam cells. The primary factor that initiates plaque formation is endothelial dysfunction or activation. Chronic endothelial injury, due e.g. to hemodynamic disturbances, hypercholesterolemia and inflammation, results in endothelial dysfunction, expression of adhesion molecules, such as integrins (I-CAM and V-CAM) and selectins (E-selectin), and release of inflammatory markers, such as IL-1 beta, IL-6 and MCP-1, resulting in increased endothelial cells permeability and, consequently, deposition of oxidized low-density lipoprotein (oxLDL). LDL and OxLDL molecules are capable of activating the Aryl Hydrocarbon Receptor (AHR), a ligand-activated transcription factor. This receptor is involved in physiological processes, metabolism of dioxins, inflammatory processes, and in the installation and clinical manifestations of cardiovascular diseases. It is not known whether OxLDL-induced activation of AHR mediates the expression of inflammatory markers and activation of inflammatory processes associated with atherosclerotic plaque formation. The present study will test the following hypothesis: Activation of the AHR by LDL and OxLDL in endothelial cells results in increased expression of adhesion molecules, such as I-CAM, V-CAM and E-Selectin, and proinflammatory cytokines, such as IL-1 beta and IL-6, which are involved in atherosclerotic plaque formation and progression. The studies will be performed in human umbilical vein endothelial cells (HUVEC) treated with FICZ (6-formylindolo[3,2-b]carbazole,L) and TCDD (2,3,7,8-Tetrachlorodibenzo-p-dioxin), AHR agonists, in the presence and absence of CH223191 (1-Methyl-N-[2-methyl-4-[2-(2-methylphenyl)diazenyl]phenyl-1H-pyrazole-5-carboxamide), AHR antagonist, or with LDL and OxLDL in the presence and absence of CH223191. Cells will be submitted to Transient Small Interfering RNA Transfection assay. Moreover, AHR expression and activity, and the expression and release of adhesion molecules and cytokines will be verified by Quantitative Real-Time PCR and western blot assays. This study will clarify the role of AHR in endothelial cells and endothelial dysfunction, initial event in the process of atherosclerotic plaque formation.