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Circ Res. 2017 Jun 23;121(1):43-55. doi: 10.1161/CIRCRESAHA.116.310509. Epub 2017 May 16.

Clinical Relevance and Role of Neuronal AT1 Receptors in ADAM17-Mediated ACE2 Shedding in Neurogenic Hypertension.

Author information

1
From the Department of Pharmacology and Experimental Therapeutics (J.X., S.S., H.X., E.L.), Cardiovascular Center of Excellence (J.X., S.S., H.X., E.L.), Neurosciences Center of Excellence (E.L.), Department of Emergency Medicine (L.M.-W.), and Department of Neurological Surgery (F.C.), Louisiana State University Health Sciences Center, New Orleans, LA; and Attoquant Diagnostics GmbH, Vienna, Austria (O.D., M.P.).
2
From the Department of Pharmacology and Experimental Therapeutics (J.X., S.S., H.X., E.L.), Cardiovascular Center of Excellence (J.X., S.S., H.X., E.L.), Neurosciences Center of Excellence (E.L.), Department of Emergency Medicine (L.M.-W.), and Department of Neurological Surgery (F.C.), Louisiana State University Health Sciences Center, New Orleans, LA; and Attoquant Diagnostics GmbH, Vienna, Austria (O.D., M.P.). elazar@lsuhsc.edu.

Abstract

RATIONALE:

Neurogenic hypertension is characterized by an increase in sympathetic activity and often resistance to drug treatments. We previously reported that it is also associated with a reduction of angiotensin-converting enzyme type 2 (ACE2) and an increase in a disintegrin and metalloprotease 17 (ADAM17) activity in experimental hypertension. In addition, while multiple cells within the central nervous system have been involved in the development of neurogenic hypertension, the contribution of ADAM17 has not been investigated.

OBJECTIVE:

To assess the clinical relevance of this ADAM17-mediated ACE2 shedding in hypertensive patients and further identify the cell types and signaling pathways involved in this process.

METHODS AND RESULTS:

Using a mass spectrometry-based assay, we identified ACE2 as the main enzyme converting angiotensin II into angiotensin-(1-7) in human cerebrospinal fluid. We also observed an increase in ACE2 activity in the cerebrospinal fluid of hypertensive patients, which was correlated with systolic blood pressure. Moreover, the increased level of tumor necrosis factor-α in those cerebrospinal fluid samples confirmed that ADAM17 was upregulated in the brain of hypertensive patients. To further assess the interaction between brain renin-angiotensin system and ADAM17, we generated mice lacking angiotensin II type 1 receptors specifically on neurons. Our data reveal that despite expression on astrocytes and other cells types in the brain, ADAM17 upregulation during deoxycorticosterone acetate-salt hypertension occurs selectively on neurons, and neuronal angiotensin II type 1 receptors are indispensable to this process. Mechanistically, reactive oxygen species and extracellular signal-regulated kinase were found to mediate ADAM17 activation.

CONCLUSIONS:

Our data demonstrate that angiotensin II type 1 receptors promote ADAM17-mediated ACE2 shedding in the brain of hypertensive patients, leading to a loss in compensatory activity during neurogenic hypertension.

KEYWORDS:

ACE2; TNF-α convertase enzyme; central nervous system; hypertension; renin–angiotensin system

PMID:
28512108
PMCID:
PMC5507353
DOI:
10.1161/CIRCRESAHA.116.310509
[Indexed for MEDLINE]
Free PMC Article

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