Nitro fatty acids: novel CD36 ligands which modulate fatty acids metabolism

GUTIERREZ MV; BONACCI G; ACTIS-DATO V; VAZQUEZ MM; CHIABRANDO G

Parana

Congreso; LIV Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB); 2018

Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB)

CD36 is a high affinity receptor that facilitates the binding and uptake of long-chain fatty acids and modified-LDL into the cell. These CD36 ligands have also been described to trigger cell signaling with different effects on cell metabolism. Since nitro-fatty acids are electrophilic lipid mediators which exhibit anti-inflammatory and cytoprotective actions in experimental models of atherosclerosis and other inflammatory diseases, we have hypothesized that nitrolipids may bind and signal through CD36 receptor. In order to this, hereby we demonstrated that Nitro-Oleic Acid (NO2-OA) displays CD36-mediated intracellular signaling via Src/ERK and AMPK pathways. Pharmacological strategies to inhibit both ligands binding to CD36 (SSO) and CD36 downstream signaling pathway for ERK (PD98059) and Src (PP1), allowed us to elucidate the specificity of the pathway involved. Therefore, to study their interaction, an in vitro assay was developed using recombinant CD36 (rCD36) and biotinylated-NO2-OA. This reaction, revealed by Western blot, exhibited that NO2-OA interacts with CD36. Competition assays with increasing molar concentration of OA, GSH and unbiotinylated NO2-OA exposed the reversibility of this interaction. Similar experimental settings showed that NO2OA impairs modified-LDL binding to rCD36, which was supplemented with experiments in RAW264.7 macrophages cell line, where pre-incubation with NO2-OA showed a decrease in cholesterol accumulation after modified-LDL treatment. Altogether this data suggests that NO2-OA acts as a CD36 ligand and triggers its downstream signaling to modulate modified-LDL uptake and fatty acid metabolism in macrophages.