Identification of angiotensin converting enzyme 2 in the rodent retina

Tikellis, C., Johnston, C. I., Forbes, J. M., Burns, W., Thomas, M. C., Lew, R. A., Yarski, M., Smith, A. I. and Cooper, M. E. (2004) Identification of angiotensin converting enzyme 2 in the rodent retina. Current Eye Research, 29 6: 419-427. doi:10.1080/02713680490517944


Author Tikellis, C.
Johnston, C. I.
Forbes, J. M.
Burns, W.
Thomas, M. C.
Lew, R. A.
Yarski, M.
Smith, A. I.
Cooper, M. E.
Title Identification of angiotensin converting enzyme 2 in the rodent retina
Journal name Current Eye Research   Check publisher's open access policy
ISSN 0271-3683
1460-2202
Publication date 2004
Sub-type Article (original research)
DOI 10.1080/02713680490517944
Open Access Status Not yet assessed
Volume 29
Issue 6
Start page 419
End page 427
Total pages 9
Place of publication Abingdon, Oxfordshire, United Kingdom
Publisher Taylor & Francis
Language eng
Formatted abstract
Purpose: An active renin-angiotensin system has been found in the retina of rats and humans. Angiotensin-converting enzyme 2 (ACE2) is a recently discovered enzymatic homologue of Angiotensin-converting enzyme (ACE) that may be an important new component of the renin-angiotensin system (RAS). This study assesses the involvement of ACE2 in the normal and diabetic rodent retina and its modulation by ACE inhibition.

Methods: Sprague-Dawley rats were randomised into three groups, control, diabetes, and diabetes plus ramipril, with diabetes induced with the β-cell toxin streptozocin and the study run for 24 weeks. ACE2 and ACE gene levels were measured using quantitative real-time polymerase chain reaction (QRT-PCR), ACE2 protein expression was confirmed by Western blotting, and ACE and ACE2 catalytic activity were measured using specific activity assays in the rat retina. Localisation of ACE2 mRNA and protein were determined by in situ hybridisation and immunohistochemistry, respectively.

Results: ACE mRNA levels were decreased to approximately 50% in the diabetic retina, but ACE2 mRNA levels were not significantly changed. ACE but not ACE2 gene expression was influenced by ramipril treatment. Following immunostaining, both ACE2 and ACE protein were localised predominantly to the inner nuclear layer (INL) but also to photoreceptors. In the diabetic retina, ACE enzyme activity was decreased, whereas ACE2 enzyme activity was increased.

Conclusions: This study has identified ACE2 gene and catalytically active protein in the rodent retina. In diabetes, the major changes were a decrease in ACE but an increase in ACE2 enzymatic activity. The ACE inhibitor ramipril did not reduce ACE2 enzymatic activity.
Keyword ACE
ACE2
RAS
Retina
Streptozocin
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Mater Research Institute-UQ (MRI-UQ)
 
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