Modulation of the Intracrine Renin Angiotensin System in Mesangial Cells Submitted to Aldosterone Stimulus
Authors: Stoll Danielle , Yokota Rodrigo , Aragão Danielle Sanches , Casarini Dulce Elena 
Published: November 2023

Currently it's well known that the classic pathway Renin/Angiotensin converting enzyme (ACE)/Angiotensin II (Ang II)/receptors AT1/AT2 it's not the only effective signalization path where the Renin‐Angiotensin‐Aldosterone System (RAAS) can act. Three new paths were described recently: ACE2/Ang (1–7)/receptor Mas, prorenin(PRR)/MAPKinasesERK1/2 e Ang IV/AT4/Insulin regulated aminopeptidase (IRAP). The identification of a local RAAS components formation and the confirmation of Ang 1‐7 central role – acting against the actions of the Ang II – opened new opportunities of study since the mesangial cells has an intracrine RAAS not well known yet. Aldosterone it's deeply related with the modulation of the classical RAAS but it was not described yet its effect in the intracrine RAAS of mesangial cells. The study of the aldosterone role in the modulation of mesangial cells it's very important to understand the renal pathologies, also it's essential comprehend the action of Ang 1‐7 in mesangial cells submitted to aldosterone stimulus since this angiotensin has showed contradictory actions depending on the tissue in study. Thus, the aim of this study is to investigate the effect of aldosterone stimulus in supra physiological, physiological and sub physiological doses and how this effect can modulate the intracrine RAAS of human mesangial cells. For that, it was performed viability assays, western blot, immunofluorescence and dosage of ACEs activity. Viability was increased with physiological doses (0.1nM) when compared with control and supra physiological dose (10nM). Western Blot technique showed an increase of ACE 2 expression after 24h of aldosterone treatment in the concentration of 10 nM when compared with control group and physiological range groups (0.1 – 1 nM) but the same did not happen after 72h of aldosterone treatment. The immunofluorescence assays showed an increase in MAS receptor production after 72h of aldosterone treatment in the supra physiological and physiological range. ACE was overexpressed after 24h with 10nM aldosterone treatment but after 72h 10nM and control groups were very similar. ACE 2 was detected in nucleus with 24h of treatment and at cytoplasm after 72h of treatment and 1, 0.1 and 0.01nM aldosterone treatment groups showed a decrease in ACE2 expression. Ang 1‐7 was localized at nucleus plasm and cytoplasm after 24h and was decreased at 1nM aldosterone concentration treatment. After 72h Ang 1‐7 was localized at nucleus membrane and nucleus and was decreased with 10nM and 1nM of aldosterone dose treatment. Ang II and renin does not presented difference in its expression with the different concentration of aldosterone treatment. The dosage of ACE activity was increased with 10nM when compared with 0.1nM aldosterone treatment only after 72h. ACE2 activity was not altered. In conclusion, the results demonstrated that aldosterone can modulate the local RAAS from mesangial cells decreasing the expression of ACE2 with no alteration in its activity, differing from ACE activity and expression that were increased

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