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Calcitriol, an active form of vitamin D, has immunomodulatory and anti-inflammatory properties. Vitamin D levels have inverse correlation with sepsis outcomes and obesity may aggravate the severity of the diseases. This study administered calcitriol to investigate its impact on sepsis-induced acute lung injury (ALI) in obese mice. Mice were fed a high-fat diet to induce obesity and were randomly assigned to control or sepsis groups, which were intravenously administered either saline (SS) or calcitriol (SD). Sepsis was induced by cecal ligation and puncture (CLP). Saline or calcitriol was injected 1 h after CLP via tail vein. Mice were sacrificed at either 12 or 24 h post-CLP and survival rates were observed. The results demonstrated that sepsis caused upregulation of inflammatory mediators and downregulation of renin-angiotensin system (RAS)-associated gene expressions in the lungs of obese mice. Cluster of differentiation 68 (CD68) expression and myeloperoxidase (MPO) activities also increased. Calcitriol treatment lowered expressions of blood and lung inflammatory mediators at 12 and/or 24 h after CLP. The RAS-proinflammatory-associated angiotensin type 1 receptor (AT1R) was lower while anti-inflammatory Mas receptor and AT2R expressions were higher at 12 h after CLP than those in the SS group. In addition, the SD group exhibited lower CD68 expression and MPO activity. Lower lung injury scores and higher survival rates were also noted in the SD group. The findings suggest that calcitriol treatment after sepsis induction upregulated RAS-associated anti-inflammatory pathway and decreased immune cell infiltration, which may have alleviated the severity of ALI of obese mice.

The acute effects of angiotensin-1–7 [ANG-(1–7)] on the reabsorptive bicarbonate flow (J[Formula: see text]) were evaluated using stationary microperfusion in vivo in the proximal tubules of spontaneously hypertensive rats (SHR) and their normotensive controls, Wistar-Kyoto (WKY) rats, using a microelectrode sensitive to H+. In WKY rats, the control J[Formula: see text] was 2.40 ± 0.10 nmol·cm−2·s−1( n = 120); losartan (10−7M) or A779 (10−6M, a specific Mas antagonist), alone or in combination with losartan, decreased the J[Formula: see text]. ANG-(1–7) had biphasic effects on J[Formula: see text]: at 10−9M, it inhibited, and at 10−6, it stimulated the flow. S3226 [10−6M, a specific Na+-H+exchanger 3 (NHE3) antagonist] decreased J[Formula: see text] and changed the stimulatory effect of ANG-(1–7) to an inhibitory one but did not alter the inhibitory action of ANG-(1–7). In SHR, the control J[Formula: see text] was 2.04 ± 0.13 nmol·cm−2·s−1( n = 56), and A779 and/or losartan reduced the flow. ANG-(1–7) at 10−9M increased J[Formula: see text], and ANG-(1–7) at 10−6M reduced it. The effects of A779, losartan, and S3226 on the J[Formula: see text] were similar to those found in WKY rats, which indicated that in SHR, the ANG-(1–7) action on the NHE3 was via Mas and ANG II type 1. The cytosolic calcium in the WKY or SHR rats was ~100 nM and was increased by ANG-(1–7) at 10−9or 10−6M. In hypertensive animals, a high plasma level of ANG-(1–7) inhibited NHE3 in the proximal tubule, which mitigated the hypertension caused by the high plasma level of ANG II.

Skeletal muscle can be affected by many physiological and pathological conditions that contribute to the development of muscle weakness, including skeletal muscle loss, inflammatory processes, or fibrosis. Therefore, research into therapeutic treatment alternatives or alleviation of these effects on skeletal muscle is of great importance.Recent studies have shown that angiotensin (1-7) [Ang-(1-7)] - a vasoactive peptide of the nonclassical axis in the renin-angiotensin system (RAS) - and its Mas receptor are expressed in skeletal muscle. Ang-(1-7), through its Mas receptor, prevents or diminishes deleterious effects induced by skeletal muscle disease or injury. Specifically, the Ang-(1-7)-Mas receptor axis modulates molecular mechanisms involved in muscle mass regulation, such as the ubiquitin proteasome pathway, the insulin-like growth factor type 1/Akt (protein kinase B) pathway, or myonuclear apoptosis, and also inflammation and fibrosis pathways.Although further research into this topic and the possible side effects of Ang-(1-7) is necessary, these findings are promising, and suggest that the Ang-(1-7)-Mas axis can be considered a possible therapeutic target for treating patients with muscular disorders.

The renin-angiotensin-aldosterone system (RAAS) plays important roles in regulating blood pressure and body fluid, which contributes to the pathophysiology of hypertension and cardiovascular/renal diseases. However, accumulating evidence has further revealed the complexity of this signal transduction system, including direct interactions with other receptors and proteins. This review focuses on recent research advances in RAAS with an emphasis on its receptors. Both systemically and locally produced angiotensin II (Ang II) bind to Ang II type 1 receptor (AT1R) and elicit strong biological functions. Recent studies have shown that Ang II–induced activation of Ang II type 2 receptor (AT2R) elicits the opposite functions to those of AT1R. However, accumulating evidence has now expanded the components of RAAS, including (pro)renin receptor, angiotensin-converting enzyme 2, angiotensin 1–7, and Mas receptor. In addition, the signal transductions of AT1R and AT2R are regulated by not only Ang II but also its receptor-associated proteins such as AT1R-associated protein and AT2R-interacting protein. Recent studies have indicated that inappropriate activation of local mineralocorticoid receptor contributes to cardiovascular and renal tissue injuries through aldosterone-dependent and -independent mechanisms. Since the mechanisms of RAAS signal transduction still remain to be elucidated, further investigations are necessary to explore novel molecular mechanisms of the RAAS, which will provide alternative therapeutic agents other than existing RAAS blockers.

The renin-angiotensin system (RAS) is one of the major regulators of physiological and pathophysiological processes in the cardiovascular system. The RAS comprises two major axes: one deleterious, composed of the angiotensin II peptide activating the AT1 receptor, and another protective, composed of the angiotensin-(1-7) (Ang-(1-7)) peptide targeting the Mas receptor. While AT1 activation is associated with vasoconstriction, fibrosis and inflammation, activation of Mas leads to vasodilation, anti-fibrotic and anti-inflammatory effects. Numerous pre-clinical studies point out Mas as a promising pharmacological target for the treatment of various cardiovascular disorders. Additionally, activation of the beneficial Ang-(1-7)/Mas axis has recently emerged as a novel strategy for treating erectile dysfunction (ED) associated with diabetes, hypertension and atherosclerosis. Aging is a well-established factor for ED development; however, little is known about local regulation of the RAS in this condition. Thus, the aim of this thesis was to assess regulation of the RAS in aging-associated ED rat model and evaluate possible options for disease management through pharmacological modulation of the RAS. In the first part of the thesis, strong upregulation of AT1 and Mas receptors was revealed in aged cavernosal tissue, which also exhibited excessive collagen deposition. At the same time, penile sections from Mas-knockout (Mas-KO) mice (FVB/N background) were similarly characterized by increased collagen content, which indicated the protective role of Mas in cavernosal fibrosis. The ability of Ang-(1-7) to inhibit TGFbeta-induced myofibroblast transition of primary cavernosal fibroblasts further suggested Mas as a promising pharmacological target to treat fibrosis-associated ED. However, the use of Ang-(1-7) as a drug is complicated by pharmacokinetic limitations, such as low bioavailability and short half-life. Development of a small-molecule Mas agonist, able to produce effects inherent to Ang-(1-7), could overcome these issues. Thus, in the second part of the thesis, in order to facilitate the discovery of novel Mas modulators by computational tools, homology modeling and molecular docking were applied to reveal the structure of the Mas-Ang-(1-7) complex. Site-directed mutagenesis studies were further performed to validate the generated model and identify crucial interaction points. In the third part of the thesis, the validated Mas model was used for virtual screening of available compound libraries (68000 compounds in total). Top-ranked candidates (120 compounds) were further tested in a cell-based assay. Obtained positive hits (40 compounds) were afterwards submitted for ex vivo testing, based on the ability of Ang-(1-7) to relax isolated mouse aortic rings, and 20 compounds among them evoked vasodilation. Finally, in order to evaluate selectivity of the vasoactive compounds towards the Mas receptor, their activity was tested using aortic rings isolated from Mas-KO mice. For two compounds, their vasodilatory ability was abolished in Mas-KO rings, which is a strong indication that the effects of identified molecules are mediated through Mas. In conclusion, this thesis highlights a protective role of the Ang-(1-7)/Mas axis in cavernosal fibrosis and proposes novel small-molecule Mas agonists, which can be further developed into first-in-class therapeutics for the treatment of fibrosis-associated ED and other cardiovascular disorders.

Angiotensin-converting enzyme 2 (ACE2) is a membrane peptidase and a component of the renin-angiotensin system (RAS) that has been found in cells of all organs, including the lungs. While ACE2 has been identified as the receptor for severe acute respiratory syndrome (SARS) coronaviruses, the mechanism underlying cell entry remains unknown. Human immunodeficiency virus infects target cells via CXC chemokine receptor 4 (CXCR4)-mediated endocytosis. Furthermore, CXCR4 interacts with dipeptidyl peptidase-4 (CD26/DPPIV), an enzyme that cleaves CXCL12/SDF-1, which is the chemokine that activates this receptor. By analogy, we hypothesized that ACE2 might also be capable of interactions with RAS-associated G-protein coupled receptors. Using resonance energy transfer and cAMP and mitogen-activated protein kinase signaling assays, we found that human ACE2 interacts with RAS-related receptors, namely the angiotensin II type 1 receptor (AT1R), the angiotensin II type 2 receptor (AT2R), and the MAS1 oncogene receptor (MasR). Although these interactions led to various alterations of signal transduction, but, more importantly, ligand binding to AT1R resulted in the downregulation of ACE2 cell surface expression, while ligand binding to AT2R, but not to MasR, resulted in upregulation of ACE2 cell surface expression. Proximity ligation assays performed in situ revealed macromolecular complexes containing ACE2 and AT1R, AT2R or MasR in adult but not fetal mouse lung tissue. These findings highlight the relevance of RAS in SARS-CoV-2 infection and the role of ACE2-containing complexes as potential therapeutic targets The Molecular Neurobiology Laboratory of the University of Barcelona is considered a research group of excellence by the Regional Catalonian Government (grup consolidat #2017 SGR 1497) SI

Aims: Activation of the angiotensin (Ang)-(1-7)/Mas receptor (R) axis protects from sympathetic overactivity. Endocytic trafficking is an essential process that regulates receptor (R) function and its ultimate cellular responses. We investigated whether the blunted responses to Ang-(1-7) in hypertensive rats are associated to an alteration in MasR trafficking. Methods and results: Brainstem neurons from Wistar-Kyoto (WKY) or spontaneously hypertensive rats (SHRs) were investigated for (i) Ang-(1-7) levels and binding and MasR expression, (ii) Ang-(1-7) responses (arachidonic acid and nitric oxide release and Akt and ERK1/2 phosphorylation), and (iii) MasR trafficking. Ang-(1-7) was determined by radioimmunoassay. MasR expression and functionality were evaluated by western blot and binding assays. MasR trafficking was evaluated by immunofluorescence. Ang-(1-7) treatment induced an increase in nitric oxide and arachidonic acid release and ERK1/2 and Akt phosphorylation in WKY neurons but did not have an effect in SHR neurons. Although SHR neurons showed greater MasR expression, Ang-(1-7)-elicited responses were substantially diminished presumably due to decreased Ang-(1-7) endogenous levels concomitant with impaired binding to its receptor. Through immunocolocalization studies, we evidenced that upon Ang-(1-7) stimulation MasRs were internalized through clathrin-coated pits and caveolae into early endosomes and slowly recycled back to the plasma membrane. However, the fraction of internalized MasRs into early endosomes was larger and the fraction of MasRs recycled back to the plasma membrane was smaller in SHR than in WKY neurons. Surprisingly, in SHR neurons but not in WKY neurons, Ang-(1-7) induced MasR translocation to the nucleus. Nuclear MasR expression and Ang-(1-7) levels were significantly greater in the nuclei of Ang-(1-7)-stimulated SHR neurons, indicating that the MasR is translocated with its ligand bound to it. Conclusion: MasRs display differential trafficking in brainstem neurons from SHRs, which may contribute to the impaired responses to Ang-(1-7). Fil: Cerniello, Flavia Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentina Fil: Silva, Mauro Gastón. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentina Fil: Carretero, Oscar A.. Henry Ford Hospitall; Estados Unidos Fil: Gironacci, Mariela Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentina

In recent decades the renin-angiotensin system has been established itself as a complex regulatory mechanism composed of different pathways involved in the control of physiological functions and, when for long term inappropriately activated, it is involved in the pathophysiology of different diseases. Among its biologically active peptides, angiotensin-(1-7) and its receptor Mas, represent an important counter-regulatory mechanism due to their antihypertensive, anti-inflammatory, anti-proliferative and antifibrotic effects. In this review, we present data that besides demonstrating the antiinflammatory effect, indicate that angiotensin-(1-7) has a crucial additional effect on the return to tissue homeostasis, that is to promote resolution of the inflammatory process. These studies point angiotensin-(1-7) or activation of Mas receptor as important therapeutic targets for the treatment of inflammatory diseases., En las últimas décadas, el sistema renina-angiotensina se ha establecido como un mecanismo regulador complejo compuesto de diferentes vías involucradas no solo en el control de funciones fisiológicas sino también en la fisiopatología de diferentes enfermedades cuando se activa de manera inapropiada y a largo plazo. Entre sus péptidos biológicamente activos, la angiotensina-(1-7) y su receptor Mas representan un mecanismo contrarregulador importante debido a efectos antihipertensivos, antiinflamatorios, antiproliferativos y antifibróticos. En esta revisión presentamos datos que, además de demostrar el efecto antiinflamatorio, indican que la angiotensina-(1-7) tiene un efecto adicional crucial en el retorno a la homeostasis del tejido, que es promover la resolución del proceso inflamatorio. Estos estudios apuntan a la angiotensina-(1-7) y/o la activación del receptor Mas, como importantes blancos terapéuticos para el tratamiento de enfermedades inflamatorias., Sociedad Argentina de Fisiología

In the current investigation, a Parkinson's disease (PD) model was established by a single direct right intrastriatal injection of the 6-hydroxydopamine (OHDA) in male Wistar rats followed by 7 daily unilateral injection of angiotensin (Ang) 1-7 in the striatum. To confirm the putative role of Mas receptor (MasR), the selective antagonist A779 was also injected intrastriatally prior to Ang 1-7 injections and a correlation analysis was performed between MasR expression and the assessed parameters. Ang 1-7 upregulated MasR expression to correlate strongly with the improved rotarod (r = 0.95, p = 0.003) and spontaneous activity task (r = 0.99, p 0.0001). This correlation extends to involve other effects of Ang 1-7, such as the increased striatal dopamine content (r = 0.98, p = 0.0005), substantia nigra pars compacta tyrosine hydroxylase immune-reactivity (r = 0.97, p = 0.001), active pY705-STAT3 (r = 0.99, p 0.0001) and SOCS3 (r = 0.99, p 0.0001). Conversely, Ang 1-7 inhibited inflammatory markers to correlate negatively with NF-κBp65 (r = -0.99, p 0.0003) and its downstream targets, high mobility group box-1 (HMGB-1; r = -0.97, p = 0.002), receptor for advanced glycation end products (RAGE; r = -0.98, p = 0.0004), and TNF-α (r = -0.99, p 0.0003), besides poly-ADP-ribose polymerase-1 (r = -0.99, p = 0.0002). In confirmation, the pre-administration of the selective MasR antagonist, A779, partially attenuated Ang 1-7-induced alterations towards 6-OHDA neurodegeneration. Collectively, our findings support a novel role for the anti-inflammatory capacity of the MasR axis to prove potential therapeutic relevance in PD via the upregulation/activation of MasR-dependent STAT3/SOCS3 cascade to negatively control the HMGB-1/RAGE/NF-κB axis hindering PD associated neuro-inflammation along with DA depletion and motor deficits.

Objective. Epidemiological studies confirm that hypertensive patients respond differently to renin-angiotensin system (RAS) inhibition depending on their gender. The aim of present work is to focus on sex-dependent differences in RAS regulation under conditions of increased salt intake. Method. To investigate RAS, we measured the expression of angiotensinogen (Agt) mRNA, angiotensin receptor type 1 (AT1) mRNA and mitochondria assembly receptor (MasR) in the liver of rats under control conditions and after feeding with a salt diet (2% NaCl). In parallel, vascular endothelial growth factor A (VEGF-A) mRNA was analyzed. Results. Regression analysis revealed sex-dependent differences in the correlation between mRNA expression of AT1 and that of Agt, MasR and VEGF-A in both groups. There was a significant negative correlation between AT1 and Agt mRNA expression in the male control group, but this correlation disappeared in males exposed to a salt diet. In females, AT1 and Agt expression correlated only in the group exposed to the salt diet. In control males, there was a borderline trend to correlation between AT1 and MasR mRNA expression. The correlation between AT1 and VEGF-A mRNA expression was significant only in the control females, however, after exposure to a salt diet, this correlation diminished. Conclusions. We hypothesize that RAS components expression is compensated differently in males and females. The observed loss of compensatory relationships in RAS between AT1 and Agt and AT1 and MasR in male rats under a salt diet can contribute to the differences observed in human with hypertension associated with an unhealthy diet.

Made available in DSpace on 2019-10-06T15:51:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-09-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The medial amygdaloid nucleus (MeA) is a limbic structure that has been demonstrated to be part of the central circuitry regulating baroreflex function. However, the local neurochemical mechanisms involved in baroreflex control by this forebrain structure is poorly understood. Thus, in the present study, we investigated the specific role of AT1, AT2, and MAS angiotensinergic receptors within the MeA in baroreflex responses in unanesthetized rats. For this, the baroreflex function was assessed using both the pharmacological approach via intravenous infusion of vasoactive agents and the sequence analysis technique. Using the pharmacological approach, we observed that bilateral microinjection of the selective AT2 receptor antagonist PD123319 into the MeA increased the tachycardia evoked by blood pressure decrease, but without affecting the reflex bradycardia caused by blood pressure increase. Besides, bilateral microinjection of the selective MAS receptor antagonist A-779 decreased both tachycardic and bradycardic responses of the baroreflex. The sequence analysis technique indicated that PD123319 into the MeA increased baroreflex effectiveness index while A-779 had an opposite effect. Treatment of the MeA with the selective AT1 receptor antagonist losartan did not affect baroreflex function assessed by either the pharmacological approach or sequence analysis technique. Overall, these findings provide evidence that MAS receptor within the MeA plays a facilitatory role in baroreflex function, whereas local AT2 receptor inhibits cardiac baroreflex responses. Results also indicate that AT1 receptor within the MeA is not involved in the control of baroreflex function. Laboratory of Pharmacology School of Pharmaceutical Sciences São Paulo State University (UNESP), Rodovia Araraquara-Jaú Km 01 (Campus Universitário), Campus Ville Joint UFSCar-UNESP Graduate Program in Physiological Sciences Laboratory of Pharmacology School of Pharmaceutical Sciences São Paulo State University (UNESP), Rodovia Araraquara-Jaú Km 01 (Campus Universitário), Campus Ville Joint UFSCar-UNESP Graduate Program in Physiological Sciences FAPESP: 2015/05922-9 FAPESP: 2017/19249-0 CNPq: 304108/2018-9 CNPq: 456405/2014-3

Alzheimer's is a worldwide neurodegenerative disease. The main pathogenic features of this disease are progressive impairment of cognitive functions associated with extracellular beta amyloid deposits, intracellular neurofibrillary tangles, neuronal death, and synapse loss. Treatment options currently available for Alzheimer's disease (AD) have limited efficacy. Angiotensin 1-7 (Ang 1-7) is a biologically active member of the Renin Angiotensin System (RAS). It is synthesized from angiotensin II (Ang II) by the action of angiotensin converting enzyme (ACE2) and forms. its ACE2 / Ang 1-7 / Mas axis with the G protein-bound Mas receptors and the G protein-linked receptor. This axis has many opposite effects of Ang II's activities such as vasoconstriction, inflammation and proliferation. Aminopeptidase A (APA) plays an important role in the metabolism of RAS, plays a role in the metabolism of Angiotensin I (Ang 1) and Ang II. In this study, in the light of literature data SH-SY5Y cells amyloid-β 1-42 (Aβ 1-42) was applied in 10 µM concentration to create Alzheimer model. In this model, the effect of Amastatin on the expression of Mas1 receptor, Ang 1-7 ligand by Western Blot (WB) technique, was applied at 10 µM concentration which inhibited APA enzyme which is involved in the metabolism of angiotensin peptides. As a result although APA inhibitor Amastatin increased Ang 1-7 levels, its effect on MasR was not observed at the studied concentration. Alzheimer dünya çapında yaygınlık gösteren nörodejeneratif bir hastalıktır. Bu hastalıkta temel patojenik özellikler ekstrasellüler beta amiloid birikimleri, intrasellüler nörofibriler tangıllar, nöronal ölüm, sinaps kaybı ile birlikte olan kognitif işlevlerde ilerleyici bir bozulmadır. Alzheimer hastalığı (AH) için şu anda mevcut olan tedavi seçenekleri sınırlı etkinliğe sahiptir. Anjiyotensin 1-7 (Ang 1-7), Renin Anjiyotensin Sistem (RAS)’inin biyolojik olarak aktif üyesidir. Anjiyotensin II (Ang II)’den anjiyotensin dönüştürücü enzim (ACE2)’nin etkisiyle sentezlenir ve G proteinine bağlı Mas reseptörleriyle ve Mas ile ilgili G protein bağlantılı reseptör ile kendi ACE2 / Ang 1-7 / Mas eksenini oluşturur. Bu eksen Ang II’nin vazokonstriksiyon, inflamasyon ve proliferasyon gibi birçok aktivitesine zıt etkilere sahiptir. Aminopeptidaz A (APA), RAS metabolizmasında Anjiyotensin I (Ang 1) ve Anjiyotensin II (Ang II) yolağında rol oynamaktadır. Son yıllarda yapılan çalışmalarda APA inhibitörlerinin etkisiyle kronik serebral hipoperfüzyon yapılan ratlarda, Ang 1-7’nin nöroprotektif olabileceği gösterilmiştir. Bu çalışmada laboratuar ortamında SH-SY5Y hücrelerine literatür verileri ışığında 10 µM konsantrasyonda amiloid-β 1-42 (Aβ 1-42 ) uygulanarak Alzheimer modeli oluşturulmuştur. Bu modele, anjiyotensin peptidlerin metabolizmasında rol oynayan APA enzimini inhibe eden, Amastatin 10 µM konsantrasyonda uygulanarak Western Blot (WB) görüntüleme tekniği ile Ang 1-7 ligandı olan Mas1 reseptör ekspresyonuna etkisi araştırılmıştır. Sonuç olarak, APA inhibitörü olan Amastatin Ang 1-7 seviyelerini artırmakla birlikte MasR’ü üzerine olan etkisi çalışılan konsantrasyonda gözlenmemiştir.

The renin–angiotensin system is an important component of the cardiovascular system. Mounting evidence suggests that the metabolic products of angiotensin I and II — initially thought to be biologically inactive — have key roles in cardiovascular physiology and pathophysiology. This non-canonical axis of the renin–angiotensin system consists of angiotensin 1–7, angiotensin 1–9, angiotensin-converting enzyme 2, the type 2 angiotensin II receptor (AT2R), the proto-oncogene Mas receptor and the Mas-related G protein-coupled receptor member D. Each of these components has been shown to counteract the effects of the classical renin–angiotensin system. This counter-regulatory renin–angiotensin system has a central role in the pathogenesis and development of various cardiovascular diseases and, therefore, represents a potential therapeutic target. In this Review, we provide the latest insights into the complexity and interplay of the components of the non-canonical renin–angiotensin system, and discuss the function and therapeutic potential of targeting this system to treat cardiovascular disease., The non-canonical axis of the renin–angiotensin system (RAS) has an important role in cardiovascular physiology and disease. In this Review, Ocaranza and colleagues discuss the interplay between components of the counter-regulatory RAS and the therapeutic potential of targeting this system to treat cardiovascular disease., Key points Chronic activation of the renin–angiotensin system (RAS) promotes cardiovascular damage, an effect that is antagonized by components of the counter-regulatory RAS.Components of the counter-regulatory RAS, including angiotensin 1–7, angiotensin 1–9, alamandine and their receptors have been found to be protective in multiple cardiovascular diseases, such as hypertension and heart failure.Numerous preclinical studies have demonstrated the beneficial effects of the counter-regulatory RAS, but clinical trials confirming these observations are still scarce.The challenges in quantitating angiotensin 1–7, angiotensin 1–9 and alamandine associated with their short plasma half-life and similarity in their molecular structures must be overcome before these peptides can be evaluated in the clinical setting.

Portal hypertension (PHT) resulting from splanchnic vasodilatation is a major cause of morbidity and mortality in patients with cirrhosis. The renin-angiotensin system (RAS) plays an important role in splanchnic vasodilatation in cirrhosis. This study investigated whether acute blockade of the vasodilatory receptors of the alternate RAS, Mas (MasR), Mas-related G-protein coupled receptor type D (MrgD), and angiotensin II type-2 receptor (AT2R) improves PHT in cirrhotic and non-cirrhotic portal hypertensive rats and counteracts systemic hypotension associated with angiotensin II type 1 receptor (AT1R) blockade. Cirrhotic bile duct ligated (BDL) or carbon tetrachloride (CCl4) injected and non-cirrhotic partial portal vein ligated (PPVL) rats were used for measurement of portal pressure (PP) and mean arterial pressure before and after an intravenous bolus injection of the MasR, MrgD, and AT2R blockers, A779, D-Pro7-Ang-(1-7) (D-Pro) and PD123319, respectively. Separate groups of rats received a combined treatment with A779 or D-Pro given 20 min after AT1R blocker losartan. Mesenteric expression of MasR, MrgD, and AT2R and circulating levels of peptide blockers were also measured. Treatment with A779 and D-Pro significantly reduced PP in cirrhotic rat models. Despite rapid degradation of A779 and D-Pro in the rat circulation, the PP lowering effect of the blockers lasted for up to 25 min. We also found that PD123319 reduced PP in CCl4 rats, possibly by blocking the MasR and/or MrgD since AT2R expression in cirrhotic mesenteric vessels was undetectable, whereas the expression of MasR and MrgD was markedly elevated. While losartan resulted in a marked reduction in PP, its profound systemic hypotensive effect was not counteracted by the combination therapy with A779 or D-Pro. In marked contrast, none of the receptor blockers had any effect on PP in non-cirrhotic PPVL rats whose mesenteric expression of MasR and MrgD was unchanged. We conclude that in addition to MasR, MrgD, a newly discovered receptor for Angiotensin-(1-7), plays a key role in splanchnic vasodilatation in cirrhosis. This implies that both MasR and MrgD are potential therapeutic targets to treat PHT in cirrhotic patients. We also conclude that the alternate RAS may not contribute to the development of splanchnic vasodilatation in non-cirrhotic PHT.

Objetivo: Compreender a ativação da via ECA II/ Ang 1-7/Receptor Mas como alvo farmacológico em patologias cardíacas. Metodologia: Trata-se de uma revisão de literatura sistemática, pesquisadas nas bases de dados EMBASE, MEDLINE e SCIELO, que para extração dos dados primários e transformação em dados secundários, foi utilizado o protocolo PRISMA. Resultados: O Sistema Renina Angiotensina é um integrante imprescindível para o adequado funcionamento fisiológico e homeostasia do sistema cardiovascular. Sendo divido em dois eixos, o clássico, que é o usado na atualidade na farmacoterapia da hipertensão e doenças cardiovasculares. E o eixo não clássico que através da via da enzima conversora de angiotensina II (ECA II), angiotensina (1-7) e receptor Mas, que tem demonstrado importante efeito vasodilatador e cardioprotetor. Demonstram um desfecho promissor e reforçam a ação efetiva do MasR como vasodilatador, cardioproteção e redução da remodelagem miocárdica. Considerações Finais: O eixo não clássico possui potencial no desenvolvimento de drogas para expansão de novas estratégias farmacológicas para as doenças cardiovasculares.

Membrane-bound angiotensin converting enzyme (ACE) 2 serves as a receptor for the Sars-CoV-2 spike protein, permitting viral attachment to target host cells. The COVID-19 pandemic brought into light ACE2, its principal product angiotensin (Ang) 1-7, and the G protein-coupled receptor for the heptapeptide (MasR), which together form a still under-recognized arm of the renin–angiotensin system (RAS). This axis counteracts vasoconstriction, inflammation and fibrosis, generated by the more familiar deleterious arm of RAS, including ACE, Ang II and the ang II type 1 receptor (AT1R). The COVID-19 disease is characterized by the depletion of ACE2 and Ang-(1-7), conceivably playing a central role in the devastating cytokine storm that characterizes this disorder. ACE2 repletion and the administration of Ang-(1-7) constitute the therapeutic options currently tested in the management of severe COVID-19 disease cases. Based on their beneficial effects, both ACE2 and Ang-(1-7) have also been suggested to slow the progression of experimental diabetic and hypertensive chronic kidney disease (CKD). Herein, we report a further step undertaken recently, utilizing this type of intervention in the management of evolving acute kidney injury (AKI), with the expectation of renal vasodilation and the attenuation of oxidative stress, inflammation, renal parenchymal damage and subsequent fibrosis. Most outcomes indicate that triggering the ACE2/Ang-(1-7)/MasR axis may be renoprotective in the setup of AKI. Yet, there is contradicting evidence that under certain conditions it may accelerate renal damage in CKD and AKI. The nature of these conflicting outcomes requires further elucidation.

Myocardial remodeling serves an important role in the pathophysiology of coronary heart disease. The angiotensin-converting enzyme (ACE)2-angiotensin-(1-7) [Ang (1‑7)]‑Mas receptor (MasR) axis is a key regulator in myocardial remodeling and development of heart failure. To investigate how ACE2‑Ang‑(1‑7)‑MasR axis function on myocardial remodeling and cardiac fibrosis in post‑myocardial infarction (MI), male Sprague‑Dawley rats (weight, 200±20 g) were used to establish the model of myocardial infarction by ligating the left coronary artery. The present study suggests that telmisartan (Tel) and olmesartan (Olm) (5 mg/kg/d) can inhibit myocardial remodeling of post‑myocardial infarction through the ACE2‑Ang (1‑7)‑MasR pathway. Administration of Tel or Olm was demonstrated to significantly inhibit collagen deposition using Masson staining. In addition, telmisartan and olmesartan was indicated to antagonize angiotensin II (Ang II) and upregulate ACE2, MasR, Ang (1‑7) expression in myocardial tissue using immunoassay and ELISA test, and the effect of Olm was more marked than that of Tel at the same dosage. Simultaneously, compared with the MI or Sham group, the mRNA and protein expression of ACE2, Ang II and MasR in myocardial tissue demonstrated a remarkable increase in the Olm group, when compared with the Tel group. Taken together, our data demonstrated that ACE2‑Ang (1‑7)‑MasR axis may present a potential protective role in the development of myocardial remodeling and may provide a new target for drug development of cardiac fibrosis. In conclusion, Olm is superior to Tel in inhibiting myocardial local Ang II level reducing myocardial collagen deposition and improving myocardial remodeling by upregulating the expression of ACE2, Ang (1‑7) and MasR.

The presence of local renin angiotensin aldosterone systems (RAAS) in the cardiovascular and renal tissues and their influence in cardiovascular and renal diseases are described. The fundamental role of ACE/Ang II/AT1 receptor axis activation as well the counterregulatory role of ACE2/Ang (1-7)/Mas receptor activation on cardiovascular and renal physiology and pathology are emphasized. The presence of a local RAS and its influence on hypertension is discussed, and finally, the hypothesis that epigenetic factors change the RAAS in utero and induce the expression of renin or Ang II inside the cells of the cardiovascular system is presented.

Adipose tissue expresses all the renin-angiotensin system (RAS) components that play an important role in the adipogenesis, lipid and glucose metabolism regulation in an auto/paracrine manner. The classical RAS has been found to be over-activated during the adipose tissue enlargement, thus elevated generation of angiotensin II (Ang II) may contribute to the obesity pathogenesis. The contemporary view on the RAS has become more complex with the discovery of alternative pathways, including angiotensin-converting enzyme 2 (ACE2)/angiotensin (Ang)-(1-7)/Mas receptor, (pro)renin receptor, as well as angiotensin IV(Ang IV)/AT4 receptor. Ang-(1-7) via Mas receptor counteracts with most of the deleterious effects of the Ang II-mediated by AT1 receptor implying its beneficial role in the glucose and lipid metabolism, oxidative stress, inflammation, and insulin resistance. Pro(renin) receptor may play a role (at least partial) in the pathogenesis of the obesity by increasing the local production of Ang II in adipose tissue as well as triggering signal transduction independently of Ang II. In this review, modulation of alternative RAS pathways in adipose tissue during obesity is discussed and the involvement of Ang-(1-7), (pro)renin and AT4 receptors in the regulation of adipose tissue homeostasis and insulin resistance is summarized.

The renin–angiotensin system (RAS) plays a commanding role in the regulation of extracellular fluid homoeostasis. Tigerstadt and Bergman first identified the RAS more than two centuries ago. By the 1980s a voyage of research and discovery into the mechanisms and actions of this system led to the development of drugs that block the RAS, which have become the mainstay for the treatment of cardiovascular and renal disease. In the last 25 years new components of the RAS have come to light, including the angiotensin type 2 receptor (AT2R) and the angiotensin-converting enzyme 2 (ACE2)/angiotensin-(1–7) [Ang(1–7)]/Mas receptor (MasR) axis. These have been shown to counter the classical actions of angiotensin II (AngII) at the predominant angiotensin type 1 receptor (AT1R). Our studies, and those of others, have demonstrated that targeting these depressor RAS pathways may be therapeutically beneficial. It is apparent that the evolution of both the pressor and depressor RAS pathways is distinct throughout life and that the depressor/pressor balance of the RAS vary between the sexes. These temporal patterns of expression suggest that therapies targeting the RAS could be optimized for discrete epochs in life.

The effects of the renin–angiotensin system (RAS) surpass the renal and cardiovascular systems to encompass other body tissues and organs, including the brain. Angiotensin II (Ang II), the most potent mediator of RAS in the brain, contributes to vascular dementia via different mechanisms, including neuronal homeostasis disruption, vascular remodeling, and endothelial dysfunction caused by increased inflammation and oxidative stress. Other RAS components of emerging significance at the level of the blood–brain barrier include angiotensin-converting enzyme 2 (ACE2), Ang(1–7), and the AT2, Mas, and AT4 receptors. The various angiotensin hormones perform complex actions on brain endothelial cells and pericytes through specific receptors that have either detrimental or beneficial actions. Increasing evidence indicates that the ACE2/Ang(1–7)/Mas axis constitutes a protective arm of RAS on the blood–brain barrier. This review provides an update of studies assessing the different effects of angiotensins on cerebral endothelial cells. The involved signaling pathways are presented and help highlight the potential pharmacological targets for the management of cognitive and behavioral dysfunctions associated with vascular dementia.

The MasR receptor (MasR) is an orphan G protein-coupled receptor proposed as a candidate for mediating the angiotensin (Ang)-converting enzyme 2-Ang-(1-7) protective axis of renin-angiotensin system. This receptor has been suggested to participate in several physiological processes including cardio- and reno-protection and regulation of the central nervous system function. Although the knowledge of the signaling mechanisms associated with MasR is essential for therapeutic purposes, these are still poorly understood. Accordingly, in the current study we aimed to characterize the signaling pathways triggered by the MasR. To do that, we measured cAMP and Ca2+ levels in both naïve and MasR transfected cells in basal conditions and upon incubation with putative MasR ligands. Besides, we evaluated activation of ERK1/2 by Ang-(1-7) in MasR transfected cells. Results indicated the existence of a high degree of MasR constitutive activity toward cAMP modulation. This effect was not mediated by the PDZ-binding motif of the MasR but by receptor coupling to Gai-adenylyl cyclase signaling pathway. Incubation of MasR transfected cells with Ang-(1-7) or the synthetic ligand AVE 0991 amplified MasR negative modulation of cAMP levels. On the other hand, we provided evidence for lack of MasR-associated modulation of Ca2+ levels by Ang-(1-7). Finally, it was determined that the MasR attenuated Ang-(1-7)-induced ERK1/2 phosphorylation mediated by AT1R. We provided further characterization of MasR signaling mechanisms regarding its constitutive activity and response to putative ligands. This information could prove useful to better describe MasR physiological role and development of therapeutic agents that could modulate its action. Fil: Burghi, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentina Fil: Echeverría, Emiliana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; Argentina Fil: Sosa, Máximo Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; Argentina Fil: Quiroga, Diego Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentina Fil: Muñoz, Marina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentina Fil: Davio, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; Argentina Fil: Monczor, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; Argentina Fil: Fernandez, Natalia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; Argentina Fil: Dominici, Fernando Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; Argentina

The renin–angiotensin system is one of the key long-term regulators of blood pressure and has been a mainstay for the treatment of cardiovascular and renal diseases for the last 30 years. In recent years, new components of the renin–angiotensin system have been discovered beyond the classical pathway that have led to the development of novel therapies targeting this system. Moreover, dual inhibitors which block the renin–angiotensin system and other systems involved in the regulation of blood pressure may provide superior treatment for cardiovascular and renal diseases.

Ang-(1-7) binds to the G-protein-coupled MAS receptor and exerts many beneficial actions in the context of acute inflammation. Ang-(1-7) reduces production and expression of many cytokines and adhesion molecules and decreases leukocyte movement in vitro and in vivo. In animal models of inflammation, administration of Ang-(1-7) or its analogues is, in general, associated with inhibition of leukocyte influx and inflammatory tissue damage. In addition, Ang-(1-7) reduces fibrogenesis in the context of chronic inflammation. Ang-(1-7) also induces the resolution of inflammation by inducing apoptosis of neutrophils and their clearance by macrophages. Altogether, the available literature suggests that drugs that mimic the action of Ang-(1-7) on the MAS receptor may represent a novel pharmacological strategy to control and treat inflammatory diseases.

Cancer cachexia is a multifactorial syndrome characterized by a progressive loss of skeletal muscle mass associated with significant functional impairment. Cachexia robs patients of their strength and capacity to perform daily tasks and live independently. Effective treatments are needed urgently. Here we investigated the therapeutic potential of activating the ‘alternative’ axis of the Renin-Angiotensin System (RAS), involving ACE2, angiotensin-(1–7), and the mitochondrial assembly receptor (MasR), for treating cancer cachexia. Plasmid overexpression of the MasR or pharmacological angiotensin-(1–7)/MasR activation did not affect healthy muscle fiber size in vitro or in vivo but attenuated atrophy induced by co-culture with cancer cells in vitro. In mice with cancer cachexia, the MasR agonist AVE 0991 slowed tumor development, reduced weight loss, improved locomotor activity, and attenuated muscle wasting, with the majority of these effects dependent on the orexigenic and not anti-tumor properties of AVE 0991. Proteomic profiling and immunohistochemistry revealed that mechanisms underlying AVE 0991 effects on skeletal muscle involved miR-23a-regulated preservation of the fast, glycolytic fibers. MasR activation is a novel regulator of muscle phenotype and AVE 0991 has orexigenic, anti-cachectic and anti-tumorigenic effects, identifying it as a promising adjunct therapy for cancer and other serious muscle wasting conditions.

Body fat distribution contributes to obesity-related metabolic and cardiovascular disorders. Visceral fat is more detrimental than subcutaneous fat. However, the mechanisms underlying visceral fat-mediated cardiometabolic dysregulation are not completely understood. Localized increases in expression of the renin angiotensin system (RAS) in adipose tissue (AT) may be implicated. We therefore investigated mRNA and protein expression of RAS components in visceral versus subcutaneous AT using paired samples from individuals undergoing surgery (N = 20, body mass index: 45.6 ± 6.2 kg/m2, and age: 44.6 ± 9.1 years). We also examined RAS-related proteins in AT obtained from individuals on renin angiotensin aldosterone system (RAAS) targeted drugs (N = 10, body mass index: 47.2 ± 9.3 kg/m2, and age: 53.3 ± 10.1 years). Comparison of protein expression between subcutaneous and visceral AT samples showed an increase in renin (p = 0.004) and no change in angiotensinogen (p = 0.987) expression in visceral AT. Among proteins involved in angiotensin peptide generation, angiotensin converting enzyme (p = 0.02) was increased in subcutaneous AT while chymase (p = 0.001) and angiotensin converting enzyme-2 (p = 0.001) were elevated in visceral fat. Furthermore, visceral fat expression of angiotensin II type-2 receptor (p = 0.007) and angiotensin II type-1 receptor (p = 0.031) was higher, and MAS receptor (p < 0.001) was lower. Phosphorylated-p53 (p = 0.147), AT fibrosis (p = 0.138) and average adipocyte size (p = 0.846) were similar in the two depots. Nonetheless, visceral AT showed increased mRNA expression of inflammatory (TNFα, p < 0.001; IL-6, p = 0.001) and oxidative stress markers (NOX2, p = 0.038; NOX4, p < 0.001). Of note, mRNA and protein expression of RAS components did not differ between subjects taking or not taking RAAS related drugs. In summary, several RAS related proteins are differentially expressed in subcutaneous versus visceral AT. This differential expression may not alter AngII but likely increases Ang1-7 generation in visceral fat. These potential differences in active angiotensin peptides and receptor expression in the two depots suggest that localized RAS may not be involved in differences in visceral vs subcutaneous AT function in obese individuals. Our findings do not support a role for localized RAS differences in visceral fat-mediated development of cardiovascular and metabolic pathology.