scholarly journals Overexpression of Central ACE2 (Angiotensin-Converting Enzyme 2) Attenuates the Pressor Response to Chronic Central Infusion of Ang II (Angiotensin II)

Hypertension ◽  
2020 ◽  
Vol 76 (5) ◽  
pp. 1514-1525
Author(s):  
Anyun Ma ◽  
Lie Gao ◽  
Ahmed M. Wafi ◽  
Li Yu ◽  
Tara Rudebush ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Angiotensin Converting Enzyme ◽  
Pressor Response ◽  
Rostral Ventrolateral Medulla ◽  
Ventrolateral Medulla ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
Intracerebroventricular Infusion

We investigated the mechanism by which ACE2 (angiotensin-converting enzyme 2) overexpression alters neurohumoral outflow and central oxidative stress. Nrf2 (nuclear factor [erythroid-derived 2]-like 2) is a master antioxidant transcription factor that regulates cytoprotective and antioxidant genes. We hypothesized that upregulation of central ACE2 inhibits the pressor response to Ang II (angiotensin II) by reducing reactive oxygen species through a Nrf2/antioxidant enzyme–mediated mechanism in the rostral ventrolateral medulla. Synapsin human Angiotensin Converting Enzyme 2 positive (SynhACE2 +/+ ) mice and their littermate controls synhACE2 −/− were used to evaluate the consequence of intracerebroventricular infusion of Ang II. In control mice, Ang II infusion evoked a significant increase in blood pressure and norepinephrine excretion, along with polydipsia and polyuria. The pressor effect of central Ang II was completely blocked in synhACE2 +/+ mice. Polydipsia, norepinephrine excretion, and markers of oxidative stress in response to central Ang II were also reduced in synhACE2 +/+ mice. The MasR (Mas receptor) agonist Ang 1–7 and blocker A779 had no effects on blood pressure. synhACE2 +/+ mice showed enhanced expression of Nrf2 in the rostral ventrolateral medulla which was blunted following Ang II infusion. Ang II evoked nuclear translocation of Nrf2 in cultured Neuro 2A (N2A) cells. In synhACE2 −/− mice, the central Ang II pressor response was attenuated by simultaneous intracerebroventricular infusion of the Nrf2 activator sulforaphane; blood pressure was enhanced by knockdown of Nrf2 in the rostral ventrolateral medulla in Nrf2 floxed (Nrf2 f/f ) mice. These data suggest that the hypertensive effects of intracerebroventricular Ang II are attenuated by selective overexpression of brain synhACE2 and may be mediated by Nrf2-upregulated antioxidant enzymes in the rostral ventrolateral medulla.

scholarly journals Overexpression of angiotensin-converting enzyme 2 attenuates tonically active glutamatergic input to the rostral ventrolateral medulla in hypertensive rats

2014 ◽  
Vol 307 (2) ◽  
pp. H182-H190 ◽  
Author(s):  
Yang-Kai Wang ◽  
Du Shen ◽  
Qiang Hao ◽  
Qiang Yu ◽  
Zhao-Tang Wu ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Converting Enzyme ◽  
Fluorescent Protein ◽  
Rostral Ventrolateral Medulla ◽  
Ventrolateral Medulla ◽  
Converting Enzyme ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Angiotensin Converting Enzyme 2 ◽  
Green Fluorescent

The rostral ventrolateral medulla (RVLM) plays a key role in cardiovascular regulation. It has been reported that tonically active glutamatergic input to the RVLM is increased in hypertensive rats, whereas angiotensin-converting enzyme 2 (ACE2) in the brain has been suggested to be beneficial to hypertension. This study was designed to determine the effect of ACE2 gene transfer into the RVLM on tonically active glutamatergic input in spontaneously hypertensive rats (SHRs). Lentiviral particles containing enhanced green fluorescent protein (lenti-GFP) or ACE2 (lenti-ACE2) were injected bilaterally into the RVLM. Both protein expression and activity of ACE2 in the RVLM were increased in SHRs after overexpression of ACE2. A significant reduction in blood pressure and heart rate in SHRs was observed 6 wk after lenti-ACE2 injected into the RVLM. The concentration of glutamate in microdialysis fluid from the RVLM was significantly reduced by an average of 61% in SHRs with lenti-ACE2 compared with lenti-GFP. ACE2 overexpression significantly attenuated the decrease in blood pressure and renal sympathetic nerve activity evoked by bilateral injection of the glutamate receptor antagonist kynurenic acid (2.7 nmol in 100 nl) into the RVLM in SHRs. Therefore, we suggest that ACE2 overexpression in the RVLM attenuates the enhanced tonically active glutamatergic input in SHRs, which may be an important mechanism underlying the beneficial effect of central ACE2 to hypertension.

scholarly journals Angiotensin-Converting Enzyme 2: The First Decade

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Nicola E. Clarke ◽  
Anthony J. Turner
Keyword(s):  
Blood Pressure ◽  
Angiotensin Converting Enzyme ◽  
Renin Angiotensin System ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Viral Receptor ◽  
Angiotensin System ◽  
Angiotensin Converting Enzyme 2 ◽  
Antiproliferative Effects ◽  
Potential Use

The renin-angiotensin system (RAS) is a critical regulator of hypertension, primarily through the actions of the vasoactive peptide Ang II, which is generated by the action of angiotensin-converting enzyme (ACE) mediating an increase in blood pressure. The discovery of ACE2, which primarily metabolises Ang II into the vasodilatory Ang-(1-7), has added a new dimension to the traditional RAS. As a result there has been huge interest in ACE2 over the past decade as a potential therapeutic for lowering blood pressure, especially elevation resulting from excess Ang II. Studies focusing on ACE2 have helped to reveal other actions of Ang-(1-7), outside vasodilation, such as antifibrotic and antiproliferative effects. Moreover, investigations focusing on ACE2 have revealed a variety of roles not just catalytic but also as a viral receptor and amino acid transporter. This paper focuses on what is known about ACE2 and its biological roles, paying particular attention to the regulation of ACE2 expression. In light of the entrance of human recombinant ACE2 into clinical trials, we discuss the potential use of ACE2 as a therapeutic and highlight some pertinent questions that still remain unanswered about ACE2.

scholarly journals Dysregulation of ACE (Angiotensin-Converting Enzyme)-2 and Renin-Angiotensin Peptides in SARS-CoV-2 Mediated Mortality and End-Organ Injuries

Hypertension ◽  
2021 ◽  
Author(s):  
Kaiming Wang ◽  
Mahmoud Gheblawi ◽  
Anish Nikhanj ◽  
Matt Munan ◽  
Erika MacIntyre ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Tumor Necrosis Factor Receptor ◽  
Renin Angiotensin System ◽  
Adverse Outcomes ◽  
Blood Collection ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
Renin Angiotensin ◽  
Angiotensin Peptides

ACE (angiotensin-converting enzyme)-2 as the target for SARS-CoV-2 also negatively regulates the renin-angiotensin system. Pathological activation of ADAM17 (A disintegrin and metalloproteinase-17) may potentiate inflammation and diminish ACE2-mediated tissue protection through proteolytic shedding, contributing to SARS-CoV-2 pathogenesis. We aim to examine plasma soluble ACE2 and angiotensin profiles in relation to outcomes by enrolling consecutive patients admitted for COVID-19 with baseline blood collection at admission and repeated sampling at 7 days. The primary outcome was 90-day mortality, and secondary outcomes were the incidence of end-organ injuries. Overall, 242 patients were included, the median age was 63 (52–74) years, 155 (64.0%) were men, and 57 (23.6%) patients reached the primary end point. Baseline soluble ACE2 was elevated in COVID-19 but was not associated with disease severity or mortality. In contrast, an upward trajectory of soluble ACE2 at repeat sampling was independently associated with an elevated risk of mortality and incidence of acute myocardial injury and circulatory shock. Similarly, an increase in soluble tumor necrosis factor receptor levels was also associated with adverse outcomes. Plasma Ang I, Ang 1-7 (angiotensin 1–7) levels, and the Ang 1-7/Ang II (angiotensin II) ratio were elevated during SARS-CoV-2 infection related to downregulation of ACE activity at baseline. Moreover, patients having an upward trajectory of soluble ACE2 were characterized by an imbalance in the Ang 1-7/Ang II ratio. The observed dysregulation of ACE2 and angiotensin peptides with disease progression suggest a potential role of ADAM17 inhibition and enhancing the beneficial Ang 1-7/Mas axis to improve outcomes against SARS-CoV-2 infection.

scholarly journals ACE2 the Janus-faced protein – from cardiovascular protection to severe acute respiratory syndrome-coronavirus and COVID-19

2020 ◽  
Vol 134 (7) ◽  
pp. 747-750 ◽  
Author(s):  
Rhian M. Touyz ◽  
Hongliang Li ◽  
Christian Delles
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Angiotensin Converting Enzyme ◽  
Basic Science ◽  
Physiological Role ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Sars Coronavirus ◽  
Multifunctional Protein ◽  
Angiotensin Converting Enzyme 2

Abstract Angiotensin converting enzyme 2 (ACE2) is the major enzyme responsible for conversion of Ang II into Ang-(1-7). It also acts as the receptor for severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2, which causes Coronavirus Disease (COVID)-19. In recognition of the importance of ACE2 and to celebrate 20 years since its discovery, the journal will publish a focused issue on the basic science and (patho)physiological role of this multifunctional protein.

Changes in angiotensin type 1 receptor binding and angiotensin-induced pressor responses in the rostral ventrolateral medulla of angiotensinogen knockout mice

2010 ◽  
Vol 298 (2) ◽  
pp. R411-R418 ◽  
Author(s):  
Daian Chen ◽  
Lisa Hazelwood ◽  
Lesley L. Walker ◽  
Brian J. Oldfield ◽  
Michael J. McKinley ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Receptor Binding ◽  
Knockout Mice ◽  
Pressor Response ◽  
Ventrolateral Medulla ◽  
Ang Ii ◽  
Wild Type ◽  
Intravenous Injections ◽  
Angiotensin Type

ANG II, the main circulating effector hormone of the renin-angiotensin system, is produced by enzymatic cleavage of angiotensinogen. The present study aimed to examine whether targeted deletion of the angiotensinogen gene ( Agt) altered brain ANG II receptor density or responsiveness to ANG II. In vitro autoradiography was used to examine the distribution and density of angiotensin type 1 (AT1) and type 2 receptors. In most brain regions, the distribution and density of angiotensin receptors were similar in brains of Agt knockout mice ( Agt −/− ) and wild-type mice. In Agt −/− mice, a small increase in AT1 receptor binding was observed in the rostral ventrolateral medulla (RVLM), a region that plays a critical role in blood pressure regulation. To examine whether Agt −/− mice showed altered responses to ANG II, blood pressure responses to intravenous injection (0.01–0.1 μg/kg) or RVLM microinjection (50 pmol in 50 nl) of ANG II were recorded in anesthetized Agt −/− and wild-type mice. Intravenous injections of phenylephrine (4 μg/kg and 2 μg/kg) were also made in both groups. The magnitude of the pressor response to intravenous injections of ANG II or phenylephrine was not different between Agt −/− and wild-type mice. Microinjection of ANG II into the RVLM induced a pressor response, which was significantly smaller in Agt −/− compared with wild-type mice (+10 ± 1 vs. +23 ± 4 mmHg, respectively, P = 0.004). Microinjection of glutamate into the RVLM (100 pmol in 10 nl) produced a robust pressor response, which was not different between Agt −/− and wild-type mice. A diminished response to ANG II microinjection in the RVLM of Agt −/− mice, despite an increased density of AT1 receptors suggests that signal transduction pathways may be altered in RVLM neurons of Agt −/− mice, resulting in attenuated cellular excitation.

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