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27. Wissenschaftlicher Kongress der Deutschen Hochdruckliga

Deutsche Liga zur Bekämpfung des hohen Blutdrucks – Deutsche Hypertonie Gesellschaft e. V.

26. bis 29.11.2003, Bonn

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Pattern of organ-specific ACE2 protein expression is conserved in rodents

Das organspezifische Expressionsmuster von ACE2 ist in Nagern konserviert

Meeting Abstract (Hypertonie 2003)

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  • presenting/speaker F. Gembardt - Universitätsklinikum Benjamin Franklin, Forschungsinstitut für Molekulare Pharmakologie (Berlin, D)
  • W.E. Siems - Universitätsklinikum Benjamin Franklin, Forschungsinstitut für Molekulare Pharmakologie (Berlin, D)
  • H.P. Schultheiss - Universitätsklinikum Benjamin Franklin, Forschungsinstitut für Molekulare Pharmakologie (Berlin, D)
  • T. Walther - Universitätsklinikum Benjamin Franklin, Forschungsinstitut für Molekulare Pharmakologie (Berlin, D)

Hypertonie 2003. 27. Wissenschaftlicher Kongress der Deutschen Hochdruckliga. Bonn, 26.-29.11.2003. Düsseldorf, Köln: German Medical Science; 2004. Doc03hochP96

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/hoch2003/03hoch196.shtml

Published: November 11, 2004

© 2004 Gembardt et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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The newly discovered angiotensin-converting enzyme related carboxypeptidase (ACE2) is a protein of approximately 75kD and shares 40% identity and 61% similarity with ACE. Biochemical analysis revealed that ACE2 cleaves angiotensin (Ang) II (Ang-(1-8)) to Ang-(1-7), we identified as an endogeneous ligand for the G protein-coupled receptor Mas. Since the Ang-(1-7)/Mas axis is involved in the blood pressure control, ACE2 is discussed to play a role in the cardiovascular regulation.

In recent investigations the distribution of mRNA for ACE2 across different tissues was shown, with the highest mRNA in testis and lung parenchyma. Surprisingly, few is known about the protein expression. Therefore the aim of this study was to investigate the ACE2 protein concentration in different tissues of rodents. We have analysed the ACE2 expression in atrium, ventricle, thymus, spleen, kidney, testis, lung, bladder, uterus, ovary, forebrain, and adipose tissue of C57Bl/6 mice and Sprague Dawley rats (both aged 3-5 months) by Western blotting, using 10µg of total protein. A commercial polyclonal antibody against ACE2 (Santa Cruz Biotechnology, Santa Cruz, USA) was used.

In contrast to its mRNA, ACE2 protein is poorly expressed in lung (20.5%; kidney expression set to 100%) and testis (29.8%). Further opposing the mRNA pattern we found the highest protein concentration in the atrium (127.6%) and ventricle (137.0%). The other investigated organs show ACE2 concentrations as follows: thymus 46.4%, spleen not detectable, bladder 25.1%, uterus 22.8%, ovary 25.3%, forebrain 82.1%, and adipose tissue 34.0%.

In rodents the ACE2 protein distribution is different from ACE, indicating a distinct function for ACE2. In contrast to its mRNA distribution, ACE2 protein is highest expressed in the heart. It points on the importance of a possible ACE2/Ang-(1-7)/Mas axis in cardiovascular physiology.