Estudo do metabolismo de angiotensinas e mecanismos de sinalização intracelular modulados pela angiotensina (1-7) no sistema nervoso central

Abstract

Further studies on neuromodulatory actions of angiotensins in the Renin Angiotensin System (RAS) could improve understanding of many central nervous system functions and disorders. The PTEN/PI3K/AKT/mTOR signaling pathway that can be activated by Angiotensin-(1-7) plays an essential role in regulating cell growth, metabolism and survival. The aim of this study was to identify and describe the main angiotensinergic metabolic pathway(s) in the hippocampus of mice (Mus musculus); Study the regulation of the PTEN/PI3K/Akt/mTOR signaling cascade from activation with Ang-(1-7) and perform inhibition assays with the Mas receptor antagonist. We also analyzed the expression of the key enzymes of the mTOR cascade, focusing on the enzyme PTEN. Identification was initially performed of the angiotensinergic metabolic pathway in the mouse hippocampus was performed by studying the angiotensinergic proteolytic activity with the hippocampal extract of Swiss mice to identify the enzymes and peptides formed from AngI and/or inhibitors in HPLC. For the study of PTEN/PI3K/Akt/mTOR signaling cascade regulation from the activation/inhibition of RAS the experiments were performed on immortalized neuroblastoma cells called SH-SY5Y and western blotting for determination of PTEN and S6k levels (total and phosphorylated). Our results showed that the characterization of the profile of the hippocampal angiotensinergic system generated preliminary results, in which from AngI, the main peptide formed was Ang-(1-7) and, to a lesser extent, Ang II. We conclude that AngII may be formed by carboxypeptids in general and Ang-(1-7) may be formed by endopeptidases. In addition, Ang-(1-7) causes a decrease in total PTEN expression, as well as a decrease in PTEN phosphorylation, in which case the decrease in phosphorylation means generation of more dephosphorylated protein and increased phosphatase activity resulting In neuroprotective effects. These results allowed us to observe that in SH-S5SY cells, the mechanism by which Ang-(1-7) activates neuroprotective mechanisms may be related to the activation of the PTEN enzyme.