Modulation of Aquaporin 2 by Renin‐Angiotensin‐Aldosterone System Peptides in Medullary and Cortical Collecting Duct Cells

Abstract

The kidney is responsible for the body water balance and homeostasis. The collecting duct system is important for this role due its responsibility, as water reabsorption and urine production. In the collecting ducts cells, it’s known that the reabsorption of water is made by the water channels named aquaporins, specially aquaporin 2 and aquaporin 3. In those channels the reabsorption is controlled by the peptide hormone vasopressin which induces the water transport due the water channels. Into the homeostatic mechanism, there is the renin‐angiotensinaldosterone system (RAAS) which regulates the water and sodium absorption as well. Previous studies of our group described that Ang 1‐7 and Ang II are inductors to the migration of AQP2 to the membrane in LLC‐PK1 cells. Therefore, the aim of this study is to evaluate if the RAAS peptides, Angiotensin II (Ang II) and Angiotensin 1‐7 (Ang 1‐7), are capable to induce water reabsorption due aquaporin 2 in Inner medullary collecting duct cells (IMCD) and cortical collecting duct cells (M1).MethodsIn this present study we evaluate the expression of aquaporin 2 after the treatment with Ang II and Ang 1‐7in different times (5,15 and 30 minutes) in both cells of the collecting duct system (medullary and cortical). The analysis of the expression was made by western blotting assay.ResultsThe western blot technique showed that in both cellular types, there is a difference between the expressions in the cells. M1 cells have showed that after different treatments times, the RAAS peptides decrease the expression of aquaporin 2 differently of the IMCD cells, that showed expression of aquaporin 2 increased when treated with Ang II. In conclusion, the results demonstrated that Ang II and Ang 1‐7can modulate the water channel aquaporin 2 expression.Support or Funding InformationCAPES, FAPESP and CNPq