ACE and ACE2 Activity in Diabetic Mice

• Published in: Diabetes (New York, N.Y.) Vol. 55; no. 7; pp. 2132 - 2139
• Main Authors: Wysocki, Jan, Ye, Minghao, Soler, Maria José, Gurley, Susan B, Xiao, Hong D, Bernstein, Kenneth E, Coffman, Thomas M, Chen, Sheldon, Batlle, Daniel
• Format: Journal Article
• Language: English
• Published: United States American Diabetes Association 01-07-2006
• Subjects: Androgens; Animals; Base Sequence; Blood pressure; Care and treatment; Diabetes; Diabetes Mellitus, Type 2 - enzymology; Diabetes Mellitus, Type 2 - genetics; Diabetics; Disease Models, Animal; DNA Primers; Enzymes; Health aspects; Kidney Cortex - enzymology; Kidney diseases; Kinetics; Mice; Mice, Knockout; Peptides; Peptidyl-Dipeptidase A - blood; Peptidyl-Dipeptidase A - deficiency; Peptidyl-Dipeptidase A - genetics; Peptidyl-Dipeptidase A - metabolism; Polymerase Chain Reaction; Protein expression; Proteins; Risk factors; RNA, Messenger - genetics
• ISSN: 0012-1797; 1939-327X
• DOI: 10.2337/db06-0033

ACE and ACE2 Activity in Diabetic Mice
Jan Wysocki 1 ,
Minghao Ye 1 ,
Maria José Soler 1 ,
Susan B. Gurley 2 ,
Hong D. Xiao 3 ,
Kenneth E. Bernstein 3 ,
Thomas M. Coffman 2 ,
Sheldon Chen 1 and
Daniel Batlle 1
1 Division of Nephrology/Hypertension, The Feinberg School of Medicine, Northwestern University, Chicago, Illinois
2 Division of Nephrology, Duke University Medical Center, Durham, North Carolina
3 Department of Pathology, Emory University, Atlanta, Georgia
Address correspondence and reprint requests to Daniel Batlle, MD, Division of Nephrology/Hypertension, The Feinberg School
of Medicine, Northwestern University, Searle 10-475, 320 E. Superior, Chicago, IL 60611. E-mail: d-batlle{at}northwestern.edu
Abstract
ACE-related carboxypeptidase (ACE2) may counterbalance the angiotensin (ANG) II–promoting effects of ACE in tissues where
both enzymes are found. Alterations in renal ACE and ACE2 expression have been described in experimental models of diabetes,
but ACE2 activity was not assessed in previous studies. We developed a microplate-based fluorometric method for the concurrent
determination of ACE and ACE2 activity in tissue samples. Enzymatic activity (relative fluorescence unit [RFU] · μg protein −1 · h −1 ) was examined in ACE and ACE2 knockout mice and in two rodent models of diabetes, the db/db and streptozotocin (STZ)-induced diabetic mice. In kidney cortex, preparations consisting mainly of proximal tubules and
cortical collecting tubules, ACE2 activity had a strong positive correlation with ACE2 protein expression (90-kDa band) in
both knockout models and their respective wild-type littermates ( r = 0.94, P < 0.01). ACE activity, likewise, had a strong positive correlation with renal cortex ACE protein expression (170-kDa band)
( r = 0.838, P < 0.005). In renal cortex, ACE2 activity was increased in both models of diabetes (46.7 ± 4.4 vs. 22.0 ± 4.7 in db/db and db/m , respectively, P < 0.01, and 22.1 ± 2.8 vs. 13.1 ± 1.5 in STZ-induced diabetic versus untreated mice, respectively, P < 0.05). ACE2 mRNA levels in renal cortex from db/db and STZ-induced diabetic mice, by contrast, were not significantly different from their respective controls. In cardiac tissue,
ACE2 activity was lower than in renal cortex, and there were no significant differences between diabetic and control mice
( db/db 2.03 ± 0.23 vs. db/m 1.85 ± 0.10; STZ-induced diabetic 0.42 ± 0.04 vs. untreated 0.52 ± 0.07 mice). ACE2 activity in renal cortex correlated positively
with ACE2 protein in db/db and db/m mice ( r = 0.666, P < 0.00 5 ) as well as in STZ-induced diabetic and control mice ( r = 0.621, P < 0.05) but not with ACE2 mRNA ( r = −0.468 and r = −0.522, respectively). We conclude that in renal cortex from diabetic mice, ACE2 expression is increased at the posttranscriptional
level. The availability of an assay for concurrent measurement of ACE and ACE2 activity should be helpful in the evaluation
of kidney-specific alterations in the balance of these two carboxypeptidases, which are involved in the control of local ANG
II formation and degradation.
Footnotes
ACE2, ACE-related carboxypeptidase; ANG, angiotensin, STZ, streptozotocin.
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore
be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact
Accepted April 6, 2006.
Received January 6, 2006.
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