Abstract P435: PROTEIN KINASE MODULATION IN THE INVESTIGATION OF ANGIOTENSIN-CONVERTING ENZYME AS A SIGNALING PATHWAY.

Abstract

The Renin-Angiotensin System (RAS) is a hormonal cascade intricately involved in regulating hydro electrolyte homeostasis and blood pressure control. The Angiotensin II peptide (ANGII) is the main and most potent biologically active product within this system, which is produced by the action of Angiotensin Converting Enzyme (ACE) on Angiotensin I. Dysregulation of the RAS is an important factor in the pathogenesis and progression of cardiovascular diseases and diabetes. Furthermore, ACE inhibitors (iECA) havebeen associated with the activation of signaling pathways, thus implicating ACE as a signal transducer molecule. This study aims to elucidate the significance of signaling pathways triggered by ACE and proteins that are differentially regulated when CHO-ECA cells are stimulated with ACE inhibitors. At approximately 80% confluency, the cells were deprived of serum and then stimulated with captopril (1μM) or enalapril (1μM) or vehicle for 2 and 5 minutes (n=10 in each group), to discerning the influence of sulfhydryl and carboxyl radicals. CHO-ECA cells were cultured for Kinase Array assay analysis using the Phospho-kinase Array Kit. This assay demonstrated that some pathways were positively modulated after captopril treatment after 2 minutes (AMPKa1, HSP27, Akt 1/2/3 T308) and after 5 (STATa/b, HSP60, b-Catenin). Some kinases were negatively modulated by captopril treatment (p53, PLC-γ1, Pyk2, eNOS). Conversely, treatment with enalapril modulated proteins differently at both treatment times. Some phospho-protein kinases were positively modulated in 2 minutes, such as PLC γ1, PYK2, and Yes, and others were positively modulated in 5 minutes (EGFR, GSK-3α/β, Lyn, PDGF Rβ, STAT 5a/b, WNK1 and STAT3 S2). The kinases AKT 1/2/3 T308, AKT 1/2/3 S743, CREB, Chk-2, c-Jun, JNK1/2/3, Lck, p38α, STAT3 Y705, β-Catenin were positively modulated in 2 and 5 minutes. The kinases eNOS, ERK1/2, GSK-3β, HSP27, p53 S15, p53 S46, MSK1/2, p70 S6 T389, p70 S6 T421/S424, PRAS40, Src, RSK1/2, RSK1/2/3, STAT1 and HSP60 were negatively modulated at 2 and 5 minutes. In conclusion, our findings augmented the current understanding of kinases modulated by captopril or enalapril, after ACE binding, highlighting the multifaceted role of ACE. Therefore, it can suggest that ACE may be a candidate to act not only as an enzyme but also as a signaling receptor and transducer protein.