An Angiotensin-(1-7) Endopeptidase in the Kidney Cortex, Proximal Tubules and Human HK-2 Epithelial Cells that is Distinct from Insulin Degrading Enzyme.

An Angiotensin-(1-7) Endopeptidase in the Kidney Cortex, Proximal Tubules and Human HK-2 Epithelial Cells that is Distinct from Insulin Degrading Enzyme. Am J Physiol Renal Physiol. 2015 Jan 7;:ajprenal.00609.2014 Authors: Wilson BA, Cruz-Diaz N, Marshall AC, Pirro NT, Su Y, Gwathmey TM, Rose JC, Chappell MC Abstract Angiotensin 1-7 (Ang-(1-7)) is expressed within the kidney and exhibits renoprotective actions that antagonizes the inflammatory, fibrotic and pro-oxidant effects of Ang II. We previously identified an endopeptidase that preferentially metabolized Ang-(1-7) to Ang-(1-4) in the brain medulla and cerebrospinal fluid (CSF) of sheep; thus, the present study established the expression of the peptidase in the kidney. Utilizing a sensitive HPLC-based approach, we demonstrate an endopeptidase activity that hydrolyzed Ang-(1-7) to Ang-(1-4) in the sheep cortex, isolated tubules and human HK-2 renal epithelial cells. The endopeptidase was markedly sensitive to the metallopeptidase inhibitor JMV-390; human HK-2 cells expressed subnanomolar sensitivity (IC50 = 0.5 nM) and the highest specific activity (123 ± 5 fmol/min/mg) in comparison to the tubules (96 ± 12 fmol/min/mg) and cortex (107 ± 9 fmol/min/mg). The endopeptidase was purified 41-fold from HK-2 cells; the activity was sensitive to JMV-390, the chelator o-phenanthroline and the mercury-containing compound p-chloromercuribenzoic acid (PCMB), but not to selective inhibitor...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research