IDENTIFICATION OF C REGULATED BY OXER1 RECEPTOR ACTIVATION IN HUMAN ADRENOCORTICAL CELLS

COOKE, MARIANA; KAZANIETZ, MARCELO; RISSO, JOAQUÍN; CORNEJO MACIEL, FABIANA; CASTILLO, ANA FERNANDA; ZHANG, S

Ciudad Autonoma de Buenos Aires

Congreso; XXIV Jornadas Anuales de la Sociedad Argentina de Biología (SAB); 2022

Sociedad Argentina de Biología (SAB)

The membrane receptor OXER1 belongs to the G protein-coupled 7TMS receptor superfamily. It is expressed in a wide variety of cell types and primarily binds a metabolic product of arachidonic acid, 5-oxo-eicosatetraenoic acid (5-oxo-ETE). OXER1 is considered an inflammatory receptor, involved in chemoattraction of circulating mononuclear cells, Ca2+ increase in neutrophils, inflammation, steroidogenesis and cancer. We detected the presence of this receptor and found evidence of its involvement in the regulation of steroid production in the human adrenocortical line cell H295R. The aim of this work was to identify proteins and signaling pathways involved in the activation of OXER1 by its natural ligand 5-oxo-ETE using proteomic and bioinformatic approaches. The technique of choice was a reverse phase protein array assay (RPPA) using antibodies for functional proteomics studies. We used H295R cells, in which OXER1 silencing was performed in order to analyze changes in protein expression/phosphorylation due to the effect of this agonist exclusively by binding to this receptor. Control and silenced H295R cells were stimulated with 5-oxo-ETE (500 nM). Proteomic analysis revealed that of the 496 proteins/phosphoproteins analyzed by RPPA, 16 and 30 proteins (after 5 min and 3 h treatment with 5-oxo-ETE, respectively) showed changes in their expression levels, which was also reversed by the absence of OXER1 (p ≤ 0.05, log2fold-change cut-off ± 0.8). With the combined use of bioinformatics tools (DAVID, STRING, PANTHER) we integrated information from different databases (KEGG, Reactome, WikiPathways). The enriched signaling pathways associated with protein profiling mainly belong to the following clusters: gene transcription (enrichment score 2.89), cellular response to stimuli and stress involving ErbB, EGFR, TGF beta signaling pathways (score 2.52), PI3K-Akt pathway and focal adhesion (score 2.42) and insulin signaling (score 2.06). In addition, PANTHER signaling pathways indicate as activated (p