Faculty Collaboration Database

Brain-selective overexpression of human Angiotensin-converting enzyme type 2 attenuates neurogenic hypertension. Circ Res 2010 Feb 05;106(2):373-82

Date

11/21/2009

Pubmed ID

19926873

Pubmed Central ID

PMC2818798

DOI

10.1161/CIRCRESAHA.109.208645

Scopus ID

2-s2.0-76349095332 (requires institutional sign-in at Scopus site)   165 Citations

Abstract

RATIONALE: Angiotensin converting enzyme type 2 (ACE2) is a new member of the brain renin-angiotensin system, that might be activated by an overactive renin-angiotensin system.

OBJECTIVE: To clarify the role of central ACE2 using a new transgenic mouse model with human (h)ACE2 under the control of a synapsin promoter, allowing neuron-targeted expression in the central nervous system.

METHODS AND RESULTS: Syn-hACE2 (SA) transgenic mice exhibit high hACE2 protein expression and activity throughout the brain. Baseline hemodynamic parameters (telemetry), autonomic function, and spontaneous baroreflex sensitivity (SBRS) were not significantly different between SA mice and nontransgenic littermates. Brain-targeted ACE2 overexpression attenuated the development of neurogenic hypertension (Ang II infusion: 600 ng/kg per minute for 14 days) and the associated reduction of both SBRS and parasympathetic tone. This prevention of hypertension by ACE2 overexpression was reversed by blockade of the Ang-(1-7) receptor (d-Ala7-Ang-[1-7]; 600 ng/kg per minute). Brain angiotensin II type 2 (AT(2))/AT(1) and Mas/AT(1) receptor ratios were significantly increased in SA mice. They remained higher following Ang II infusion but were dramatically reduced after Ang-(1-7) receptor blockade. ACE2 overexpression resulted in increased NOS and NO levels in the brain, and prevented the Ang II-mediated decrease in NOS expression in regions modulating blood pressure regulation.

CONCLUSIONS: ACE2 overexpression attenuates the development of neurogenic hypertension partially by preventing the decrease in both SBRS and parasympathetic tone. These protective effects might be mediated by enhanced NO release in the brain resulting from Mas and AT(2) receptor upregulation. Taken together, our data highlight the compensatory role of central ACE2 and its potential benefits as a therapeutic target for neurogenic hypertension.

Author List

Feng Y, Xia H, Cai Y, Halabi CM, Becker LK, Santos RA, Speth RC, Sigmund CD, Lazartigues E

Author

Curt Sigmund PhD Chair, Professor in the Physiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Angiotensin II
Animals
Baroreflex
Blood Pressure
Blotting, Western
Brain
Brain Stem
Female
Gene Expression Regulation, Enzymologic
Humans
Hypertension
Immunohistochemistry
Male
Mice
Mice, Inbred C57BL
Mice, Transgenic
Nitric Oxide
Nitric Oxide Synthase
Parasympathetic Nervous System
Peptide Fragments
Peptidyl-Dipeptidase A
Receptors, Angiotensin
Reverse Transcriptase Polymerase Chain Reaction