scholarly journals Brain angiotensin-converting enzymes: role of angiotensin-converting enzyme 2 in processing angiotensin II in mice

2008 ◽  
Vol 93 (5) ◽  
pp. 665-675 ◽  
Author(s):  
Khalid M. Elased ◽  
Tatiana Sousa Cunha ◽  
Fernanda Klein Marcondes ◽  
Mariana Morris
2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Nisha Sharma ◽  
Anil Bhanudas Gaikwad

Abstract Background and Aims In clinical settings, diabetics remain on higher risk of ischemic renal injury (IRI) than nondiabetic patients. In addition, IRI predisposes distant organs to dysfunction such as neurological impairments via activation of the pressor arm of renin-angiotensin system (RAS). In contrast, the role of depressor arm of RAS on IRI-associated neurological sequalae remains elusive. Hence, this study explored the role of angiotensin II type 2 receptor (AT2R) and angiotensin-converting enzyme 2 (ACE2) in IRI-associated neurological dysfunctions under nondiabetic (ND) and diabetes mellitus (DM) condition. Method Type 1 diabetes was induced by injecting streptozotocin (55 mg/kg i.p.). ND and DM rats with bilateral IRI were treated with AT2R agonist-Compound 21 (C21) (0.3 mg/kg/day, i.p.) or ACE2 activator-Diminazene Aceturate (Dize), (5 mg/kg/day, p.o.) per se or in combination therapy. Behavioural, biochemical, and histopathological analysis were done to assess IRI-induced neurological impairment. Moreover, immunohistochemistry, ELISA and qRT-PCR experiments were conducted for molecular mechanism analysis. Result In ND and DM rats, IRI caused hippocampal complications as evidenced by increased MDA and nitrite levels, augmented inflammatory cytokines (granulocyte colony stimulating factor, glial fibrillary acidic protein), altered protein and mRNA expressions of Ang II, Ang-(1-7), AT1R, AT2R and MasR. In contrast, concomitant therapy of C21 and Dize effectively normalised aforementioned hippocampal alterations. The protective effect of combination therapy was exerted due to augmented protein and mRNA levels of depressor arm components. Conclusion The current study demonstrated the protective role of AT2R agonist and ACE2 activator in IRI-associated neurological dysfunction through preventing oxidative stress, inflammation and upregulating brain depressor arm of RAS under ND and DM conditions.


2020 ◽  
Vol 10 (18) ◽  
pp. 6224 ◽  
Author(s):  
Leonardo Mancini ◽  
Vincenzo Quinzi ◽  
Stefano Mummolo ◽  
Giuseppe Marzo ◽  
Enrico Marchetti

SARS-CoV-2 propagation in the world has led to rapid growth and an acceleration in the discoveries and publications of various interests. The main focus of a consistent number of studies has been the role of angiotensin-converting enzyme 2 (ACE2) in binding the virus and its role in expression of the inflammatory response after transmission. ACE2 is an enzyme involved in the renin–angiotensin system (RAS), whose key role is to regulate and counter angiotensin-converting enzyme (ACE), reducing the amount of angiotensin II and increasing angiotensin 1–7 (Ang1–7), making it a promising drug target for treating cardiovascular diseases. The classical RAS axis, formed by ACE, angiotensin II (Ang II), and angiotensin receptor type 1 (AT1), activates several cell functions and molecular signalling pathways related to tissue injury and inflammation. In contrast, the RAS axis composed of ACE2, Ang1–7, and Mas receptor (MasR) exerts the opposite effect concerning the inflammatory response and tissue fibrosis. Recent studies have shown the presence of the RAS system in periodontal sites where osteoblasts, fibroblasts, and osteoclasts are involved in bone remodelling, suggesting that the role of ACE2 might have a fundamental function in the under- or overexpression of cytokines such as interleukin-6 (IL-6), interleukin-7 (IL-7), tumour necrosis factor alpha (TNF-α), interleukin-2 (IL-2), interleukin-1 beta (IL-1β), monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-beta (TGF-β), associated with a periodontal disorder, mainly during coinfection with SARS-CoV-2, where ACE2 is underexpressed and cannot form the ACE2–Ang1–7–MasR axis. This renders the patient unresponsive to an inflammatory process, facilitating periodontal loss.


2020 ◽  
Author(s):  
Rafael Luzes ◽  
Humberto Muzi-Filho ◽  
Amaury Pereira-Acácio ◽  
Thuany Crisóstomo ◽  
Adalberto Vieyra

AbstractThe renal lesions – including severe acute kidney injury – are severe outcomes in SARS-CoV-2 infections. There are no reports regarding the influence of the nutritional status on the severity and progress of these lesions. Ageing is also an important risk factor. In the present communication we compare the influence of overweight and undernutrition in the levels of renal angiotensin converting enzymes 1 and 2. Since the renin-angiotensin-aldosterone system (RAAS) has been implicated in the progress of kidney failure during Covid-19, we also investigated the influence of Angiotensin-(3–4) (Ang-(3–4)) the shortest angiotensin-derived peptide, which is considered the physiological antagonist of several angiotensin II effects. We found that both overweight and undernutrition downregulate the levels of angiotensin converting enzyme 2 (ACE2) without influence on the levels of ACE1 in kidney rats. Administration of Ang-(3–4) recovers the control levels of ACE2 in overweight but not in undernourished rats. We conclude that chronic and opposite nutritional conditions play a central role in the pathophysiology of renal Covid-19 lesions, and that the role of RAAS is also different in overweight and undernutrition.


Author(s):  
Seyed-Mohammad Ghahestani ◽  
Javad Mahmoudi ◽  
Sakineh Hajebrahimi ◽  
Amir-Babak Sioofy-Khojine ◽  
Hanieh Salehi-Pourmehr ◽  
...  

The new virus SARS-CoV-2 is savagely spreading out over the world. The biologic studies show that the target receptor for the virus might be angiotensin-converting enzyme 2 (ACE2). This peptide is responsible for converting angiotensin II (Ang II), which is a profoundly active peptide, into Ang 1-7 with quite a balancing barbell function. It is emphasized that the direct target of the virus is ACE2 underlining the obvious difference with ACE. Nevertheless, we hypothesized that a back load build up effect on Ang II may usurp the ACE capacity and subsequently leave the bradykinin system unabated. We think there are clinical clues for dry cough and the presumed aggravating role of ACE inhibitors like captopril on the disease process. Thereby, we speculated that inhibition of bradykinin synthesis and/or blockade of bradykinin B2 receptor using Aprotinin/ecallantide and Icatibant, respectively, may hold therapeutic promise in severe cases and these molecules can be advanced to clinical trials.


TH Open ◽  
2020 ◽  
Vol 04 (02) ◽  
pp. e138-e144 ◽  
Author(s):  
Wolfgang Miesbach

AbstractThe activated renin–angiotensin system induces a prothrombotic state resulting from the imbalance between coagulation and fibrinolysis. Angiotensin II is the central effector molecule of the activated renin–angiotensin system and is degraded by the angiotensin-converting enzyme 2 to angiotensin (1–7). The novel coronavirus infection (classified as COVID-19) is caused by the new coronavirus SARS-CoV-2 and is characterized by an exaggerated inflammatory response that can lead to severe manifestations such as acute respiratory distress syndrome, sepsis, and death in a proportion of patients, mostly elderly patients with preexisting comorbidities. SARS-CoV-2 uses the angiotensin-converting enzyme 2 receptor to enter the target cells, resulting in activation of the renin–angiotensin system. After downregulating the angiotensin-converting enzyme 2, the vasoconstrictor angiotensin II is increasingly produced and its counterregulating molecules angiotensin (1–7) reduced. Angiotensin II increases thrombin formation and impairs fibrinolysis. Elevated levels were strongly associated with viral load and lung injury in patients with severe COVID-19. Therefore, the complex clinical picture of patients with severe complications of COVID-19 is triggered by the various effects of highly expressed angiotensin II on vasculopathy, coagulopathy, and inflammation. Future treatment options should focus on blocking the thrombogenic and inflammatory properties of angiotensin II in COVID-19 patients.


2020 ◽  
Vol 134 (7) ◽  
pp. 747-750 ◽  
Author(s):  
Rhian M. Touyz ◽  
Hongliang Li ◽  
Christian Delles

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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