Combination of Angiotensin (1-7) Agonists and Convalescent Plasma as a New Strategy to Overcome Angiotensin Converting Enzyme 2 (ACE2) Inhibition for the Treatment of COVID-19

Coronavirus disease-2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently the most concerning health problem worldwide. SARS-CoV-2 infects cells by binding to angiotensin-converting enzyme 2 (ACE2). It is believed that the differential response to SARS-CoV-2 is correlated with the differential expression of ACE2. Several reports proposed the use of ACE2 pharmacological inhibitors and ACE2 antibodies to block viral entry. However, ACE2 inhibition is associated with lung and cardiovascular pathology and would probably increase the pathogenesis of COVID-19. Therefore, utilizing ACE2 soluble analogs to block viral entry while rescuing ACE2 activity has been proposed. Despite their protective effects, such analogs can form a circulating reservoir of the virus, thus accelerating its spread in the body. Levels of ACE2 are reduced following viral infection, possibly due to increased viral entry and lysis of ACE2 positive cells. Downregulation of ACE2/Ang (1-7) axis is associated with Ang II upregulation. Of note, while Ang (1-7) exerts protective effects on the lung and cardiovasculature, Ang II elicits pro-inflammatory and pro-fibrotic detrimental effects by binding to the angiotensin type 1 receptor (AT1R). Indeed, AT1R blockers (ARBs) can alleviate the harmful effects associated with Ang II upregulation while increasing ACE2 expression and thus the risk of viral infection. Therefore, Ang (1-7) agonists seem to be a better treatment option. Another approach is the transfusion of convalescent plasma from recovered patients with deteriorated symptoms. Indeed, this appears to be promising due to the neutralizing capacity of anti-COVID-19 antibodies. In light of these considerations, we encourage the adoption of Ang (1-7) agonists and convalescent plasma conjugated therapy for the treatment of COVID-19 patients. This therapeutic regimen is expected to be a safer choice since it possesses the proven ability to neutralize the virus while ensuring lung and cardiovascular protection through modulation of the inflammatory response.

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Exosome-Mediated Transfer of ACE2 (Angiotensin-Converting Enzyme 2) from Endothelial Progenitor Cells Promotes Survival and Function of Endothelial Cell

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/4213541 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11 ◽

Cited By ~ 9

Author(s):

Jinju Wang ◽

Shuzhen Chen ◽

Ji Bihl

Keyword(s):

Membrane Potential ◽

Angiotensin Converting Enzyme ◽

Progenitor Cells ◽

Endothelial Progenitor Cells ◽

Protective Effects ◽

Ang Ii ◽

Converting Enzyme ◽

Endothelial Progenitor ◽

Angiotensin Converting Enzyme 2 ◽

Mitochondrial Functions

Angiotensin-converting enzyme 2 (ACE2) is an emerging cardiovascular protective target that mediates the metabolism of angiotensin (Ang) II into Ang (1–7). Our group has demonstrated that ACE2 overexpression enhances the function of endothelial progenitor cells (EPCs). Here, we investigated whether ACE2-primed EPCs (ACE2-EPCs) can protect cerebral microvascular endothelial cells (ECs) against injury and dysfunction in an in vitro model, with focusing on their exosomal and cytokine paracrine effects on endothelial mitochondria. Human EPCs were transfected with lentivirus containing null or human ACE2 cDNA (denoted as Null-EPCs and ACE2-EPCs, respectively). Their conditioned culture media, w/wo depletion of exosomes (ACE2-EPC-CMEX-, Null-EPC-CMEX-, ACE2-EPC-CM, and Null-EPC-CM), were used for coculture experiments. EC injury and dysfunction model was induced by Ang II before coculture. Apoptosis, angiogenic ability, mitochondrion functions (ROS production, membrane potential, fragmentation), and gene expressions (ACE2, Nox2, and Nox4) of ECs were analyzed. The supernatant was collected for measuring the levels of ACE2, Ang II/Ang-(1–7), and growth factors (VEGF and IGF). Our results showed that (1) ACE2-EPC-CM had higher levels of ACE2, Ang (1–7), VEGF, and IGF than that of Null-EPC-CM. (2) Ang II-injured ECs displayed an increase of apoptotic rate and reduction in tube formation and migration abilities, which were associated with ACE2 downregulation, Ang II/Ang (1–7) imbalance, Nox2/Nox4 upregulation, ROS overproduction, an increase of mitochondrion fragmentation, and a decrease of membrane potential. (3) ACE2-EPC-CM had better protective effects than Null-EPC-CM on Ang II-injured ECs, which were associated with the improvements on ACE2 expression, Ang II/Ang (1–7) balance, and mitochondrial functions. (4) ACE2-EPC-CMEX- and Null-EPC-CMEX- showed reduced effects as compared to ACE2-EPCs-CM and Null-EPCs-CM. In conclusion, our data demonstrate that ACE2 overexpression can enhance the protective effects of EPCs on ECs injury, majorly through the exosomal effects on mitochondrial function.

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Stimulation of Angiotensin Converting Enzyme 2: A Novel Treatment Strategy for Diabetic Nephropathy

Frontiers in Physiology ◽

10.3389/fphys.2021.813012 ◽

2022 ◽

Vol 12 ◽

Author(s):

Haru Nomura ◽

Sanjaya Kuruppu ◽

Niwanthi W. Rajapakse

Keyword(s):

Diabetic Nephropathy ◽

Angiotensin Converting Enzyme ◽

Protective Effects ◽

Ang Ii ◽

Converting Enzyme ◽

Converting Enzyme Inhibitors ◽

Kidney Fibrosis ◽

Angiotensin Converting Enzyme 2 ◽

Promising Therapeutic Approach ◽

End Stage

Despite current therapies for diabetic nephropathy, many patients continue to progress to end-stage renal disease requiring renal replacement therapy. While the precise mechanisms underlying diabetic nephropathy remain to be determined, it is well established that chronic activation of the renin angiotensin aldosterone system (RAAS) plays a substantial role in the pathogenesis of diabetic nephropathy. Angiotensin converting enzyme 2 (ACE2), the enzyme responsible for activating the reno-protective arm of the RAAS converts angiotensin (Ang) II into Ang 1-7 which exerts reno-protective effects. Chronic RAAS activation leads to kidney inflammation and fibrosis, and ultimately lead to end-stage kidney disease. Currently, angiotensin converting enzyme inhibitors and Ang II receptor blockers are approved for renal fibrosis and inflammation. Targeting the reno-protective arm of the RAAS should therefore, provide further treatment options for kidney fibrosis and inflammation. In this review, we examine how targeting the reno-protective arm of the RAAS can ameliorate kidney inflammation and fibrosis and rescue kidney function in diabetic nephropathy. We argue tissue ACE2 stimulation provides a unique and promising therapeutic approach for diabetic nephropathy.

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The Effects of Aβ1-42 Binding to the SARS-CoV-2 Spike Protein S1 Subunit and Angiotensin-Converting Enzyme 2

International Journal of Molecular Sciences ◽

10.3390/ijms22158226 ◽

2021 ◽

Vol 22 (15) ◽

pp. 8226

Author(s):

John Tsu-An Hsu ◽

Chih-Feng Tien ◽

Guann-Yi Yu ◽

Santai Shen ◽

Yi-Hsuan Lee ◽

...

Keyword(s):

Angiotensin Converting Enzyme ◽

Viral Entry ◽

Negative Impact ◽

Spike Protein ◽

Infection Model ◽

Converting Enzyme ◽

Viral Receptor ◽

Angiotensin Converting Enzyme 2 ◽

People With Dementia ◽

The Impact

Increasing evidence suggests that elderly people with dementia are vulnerable to the development of severe coronavirus disease 2019 (COVID-19). In Alzheimer’s disease (AD), the major form of dementia, β-amyloid (Aβ) levels in the blood are increased; however, the impact of elevated Aβ levels on the progression of COVID-19 remains largely unknown. Here, our findings demonstrate that Aβ1-42, but not Aβ1-40, bound to various viral proteins with a preferentially high affinity for the spike protein S1 subunit (S1) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the viral receptor, angiotensin-converting enzyme 2 (ACE2). These bindings were mainly through the C-terminal residues of Aβ1-42. Furthermore, Aβ1-42 strengthened the binding of the S1 of SARS-CoV-2 to ACE2 and increased the viral entry and production of IL-6 in a SARS-CoV-2 pseudovirus infection model. Intriguingly, data from a surrogate mouse model with intravenous inoculation of Aβ1-42 show that the clearance of Aβ1-42 in the blood was dampened in the presence of the extracellular domain of the spike protein trimers of SARS-CoV-2, whose effects can be prevented by a novel anti-Aβ antibody. In conclusion, these findings suggest that the binding of Aβ1-42 to the S1 of SARS-CoV-2 and ACE2 may have a negative impact on the course and severity of SARS-CoV-2 infection. Further investigations are warranted to elucidate the underlying mechanisms and examine whether reducing the level of Aβ1-42 in the blood is beneficial to the fight against COVID-19 and AD.

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ACE2 Shedding and the Role in COVID-19

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.789180 ◽

2022 ◽

Vol 11 ◽

Author(s):

Jieqiong Wang ◽

Huiying Zhao ◽

Youzhong An

Keyword(s):

Amino Acids ◽

Viral Entry ◽

Kidney Injury ◽

Renin Angiotensin System ◽

Underlying Mechanism ◽

Ang Ii ◽

Converting Enzyme ◽

Angiotensin System ◽

Angiotensin Converting Enzyme 2 ◽

Transmembrane Glycoprotein

Angiotensin converting enzyme 2 (ACE2), a transmembrane glycoprotein, is an important part of the renin-angiotensin system (RAS). In the COVID-19 epidemic, it was found to be the receptor of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2). ACE2 maintains homeostasis by inhibiting the Ang II-AT1R axis and activating the Ang I (1-7)-MasR axis, protecting against lung, heart and kidney injury. In addition, ACE2 helps transport amino acids across the membrane. ACE2 sheds from the membrane, producing soluble ACE2 (sACE2). Previous studies have pointed out that sACE2 plays a role in the pathology of the disease, but the underlying mechanism is not yet clear. Recent studies have confirmed that sACE2 can also act as the receptor of SARS-COV-2, mediating viral entry into the cell and then spreading to the infective area. Elevated concentrations of sACE2 are more related to disease. Recombinant human ACE2, an exogenous soluble ACE2, can be used to supplement endogenous ACE2. It may represent a potent COVID-19 treatment in the future. However, the specific administration concentration needs to be further investigated.

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

Hypertension ◽

10.1161/hypertensionaha.121.18295 ◽

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.

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

Clinical Science ◽

10.1042/cs20200363 ◽

2020 ◽

Vol 134 (7) ◽

pp. 747-750 ◽

Cited By ~ 20

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.

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

Hypertension ◽

10.1161/hypertensionaha.120.15681 ◽

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.

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Differential Virological and Immunological Outcome of Severe Acute Respiratory Syndrome Coronavirus Infection in Susceptible and Resistant Transgenic Mice Expressing Human Angiotensin-Converting Enzyme 2

Journal of Virology ◽

10.1128/jvi.02272-08 ◽

2009 ◽

Vol 83 (11) ◽

pp. 5451-5465 ◽

Cited By ~ 24

Author(s):

Naoko Yoshikawa ◽

Tomoki Yoshikawa ◽

Terence Hill ◽

Cheng Huang ◽

Douglas M. Watts ◽

...

Keyword(s):

T Cells ◽

Severe Acute Respiratory Syndrome ◽

Angiotensin Converting Enzyme ◽

Viral Infection ◽

Inflammatory Responses ◽

Fatal Outcome ◽

Converting Enzyme ◽

Angiotensin Converting Enzyme 2 ◽

Inflammatory Infiltrates ◽

The Brain

ABSTRACT We previously reported that transgenic (Tg) mice expressing human angiotensin-converting enzyme 2 (hACE2), the receptor for severe acute respiratory syndrome coronavirus (SARS-CoV), were highly susceptible to SARS-CoV infection, which resulted in the development of disease of various severity and even death in some lineages. In this study, we further characterized and compared the pathogeneses of SARS-CoV infection in two of the most stable Tg lineages, AC70 and AC22, representing those susceptible and resistant to the lethal SARS-CoV infection, respectively. The kinetics of virus replication and the inflammatory responses within the lungs and brains, as well as the clinical and pathological outcomes, were assessed in each lineage. In addition, we generated information on lymphocyte subsets and mitogen-mediated proliferation of splenocytes. We found that while both lineages were permissive to SARS-CoV infection, causing elevated secretion of many inflammatory mediators within the lungs and brains, viral infection appeared to be more intense in AC70 than in AC22 mice, especially in the brain. Moreover, such infection was accompanied by a more profound immune suppression in the former, as evidenced by the extensive loss of T cells, compromised responses to concanavalin A stimulation, and absence of inflammatory infiltrates within the brain. We also found that CD8+ T cells were partially effective in attenuating the pathogenesis of SARS-CoV infection in lethality-resistant AC22 mice. Collectively, our data revealed a more intense viral infection and immunosuppression in AC70 mice than in AC22 mice, thereby providing us with an immunopathogenic basis for the fatal outcome of SARS-CoV infection in the AC70 mice.

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Dual RAS blockade normalizes angiotensin-converting enzyme-2 expression and prevents hypertension and tubular apoptosis in Akita angiotensinogen-transgenic mice

AJP Renal Physiology ◽

10.1152/ajprenal.00340.2011 ◽

2012 ◽

Vol 302 (7) ◽

pp. F840-F852 ◽

Cited By ~ 39

Author(s):

Chao-Sheng Lo ◽

Fang Liu ◽

Yixuan Shi ◽

Hasna Maachi ◽

Isabelle Chenier ◽

...

Keyword(s):

Angiotensin Converting Enzyme ◽

Renin Angiotensin System ◽

Ang Ii ◽

Converting Enzyme ◽

Angiotensin Converting Enzyme 2 ◽

Gene And Protein Expression ◽

Intrarenal Ras ◽

Renal Proximal Tubular ◽

The Right

We investigated the effects of dual renin-angiotensin system (RAS) blockade on angiotensin-converting enzyme-2 (Ace2) expression, hypertension, and renal proximal tubular cell (RPTC) apoptosis in type 1 diabetic Akita angiotensinogen (Agt)-transgenic (Tg) mice that specifically overexpress Agt in their RPTCs. Adult (11 wk old) male Akita and Akita Agt-Tg mice were treated with two RAS blockers (ANG II receptor type 1 blocker losartan, 30 mg·kg−1·day−1) and angiotensin-converting enzyme (ACE) inhibitor perindopril (4 mg·kg−1·day−1) in drinking water. Same-age non-Akita littermates and Agt-Tg mice served as controls. Blood pressure, blood glucose, and albuminuria were monitored weekly. The animals were euthanized at age 16 wk. The left kidneys were processed for immunohistochemistry and apoptosis studies. Renal proximal tubules were isolated from the right kidneys to assess gene and protein expression. Urinary ANG II and ANG 1–7 were quantified by ELISA. RAS blockade normalized renal Ace2 expression and urinary ANG 1–7 levels (both of which were low in untreated Akita and Akita Agt-Tg), prevented hypertension, albuminuria, tubulointerstitial fibrosis and tubular apoptosis, and inhibited profibrotic and proapoptotic gene expression in RPTCs of Akita and Akita Agt-Tg mice compared with non-Akita controls. Our results demonstrate the effectiveness of RAS blockade in preventing intrarenal RAS activation, hypertension, and nephropathy progression in diabetes and support the important role of intrarenal Ace2 expression in modulating hypertension and renal injury in diabetes.

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Targeting angiotensin-converting enzyme 2 as a new therapeutic target for cardiovascular diseases

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2013-0488 ◽

2014 ◽

Vol 92 (7) ◽

pp. 558-565 ◽

Cited By ~ 17

Author(s):

Nirmal Parajuli ◽

Tharmarajan Ramprasath ◽

Vaibhav B. Patel ◽

Wang Wang ◽

Brendan Putko ◽

...

Keyword(s):

Heart Failure ◽

Cardiovascular Diseases ◽

Angiotensin Converting Enzyme ◽

Therapeutic Target ◽

Ang Ii ◽

Converting Enzyme ◽

Angiotensin Converting Enzyme 2 ◽

Heart Failure Patients ◽

Positive Effects ◽

Mas Receptor

Angiotensin-converting enzyme 2 (ACE2) is a monocarboxypeptidase that metabolizes several vasoactive peptides, including angiotensin II (Ang-II; a vasoconstrictive/proliferative peptide), which it converts to Ang-(1–7). Ang-(1–7) acts through the Mas receptor to mediate vasodilatory/antiproliferative actions. The renin–angiotensin system involving the ACE–Ang-II–Ang-II type-1 receptor (AT1R) axis is antagonized by the ACE2–Ang-(1–7)–Mas receptor axis. Loss of ACE2 enhances adverse remodeling and susceptibility to pressure and volume overload. Human recombinant ACE2 may act to suppress myocardial hypertrophy, fibrosis, inflammation, and diastolic dysfunction in heart failure patients. The ACE2–Ang-(1–7)–Mas axis may present a new therapeutic target for the treatment of heart failure patients. This review is mainly focused on the analysis of ACE2, including its influence and potentially positive effects, as well as the potential use of human recombinant ACE2 as a novel therapy for the treatment cardiovascular diseases, such as hypertension and heart failure.

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