key: cord-0035311-hy5o8iz1
authors: Alenina, Natalia; Bader, Michael
title: Genetic Models
date: 2019-05-22
journal: Angiotensin-(1-7)
DOI: 10.1007/978-3-030-22696-1_3
sha: 0d83eeb5e9a11933e9c2fb008b455690d6b3dee6
doc_id: 35311
cord_uid: hy5o8iz1

Genetically altered rat and mouse models have been instrumental in the functional analysis of genes in a physiological context. In particular, studies on the renin-angiotensin system (RAS) have profited from this technology in the past. In this review, we summarize the existing animal models for the protective axis of the RAS consisting of angiotensin-converting enzyme 2 (ACE2), angiotensin-(1-7)(Ang-(1-7), and its receptor Mas. With the help of models with altered expression of the components of this axis in the brain and cardiovascular organs, its physiological and pathophysiological functions have been elucidated. Thus, novel opportunities for therapeutic interventions in cardiovascular diseases were revealed targeting ACE2 or Mas.

Transgenic and knockout animal models are the most effective tools to study cardiovascular hormone systems, since they reveal effects of changes in single components of these systems on the whole physiology. In particular, studies on the renin-angiotensin systems (RAS) have profited from this technology in recent decades [3, 5, 58] . Therefore, it was warranted to establish such models also for the novel RAS consisting of ACE2, Ang-(1-7), and Mas ( Table 1 ). Despite that these three components comprise a common axis, distinct phenotypes of models with one of the components altered are expected since each of the three components has distinct additional functions independent from the two other molecules. ACE2, in particular, is a protein with several functions, a carboxypeptidase metabolizing a multitude of peptides, such as AngII and apelins, thereby either activating or inactivating them [104] , a protein with a collectrin domain, which is involved in amino acid uptake in the gut [34, 95] , and the receptor for the severe acute respiratory syndrome (SARS) coronavirus [45] . Moreover, also Ang-(1-7) may interact with other receptors than Mas and Mas may have other ligands or exert ligand-independent effects [4, 86] . 

Since the ACE2 gene is localized on the X-chromosome, male mice with ACE2 gene deletion (ACE2 −/y ) are already deficient in the enzyme in the hemizygous state. Based on the pleiotropic actions of this protein, mice lacking ACE2 are expected to exhibit increased levels of AngII, decreased levels of Ang-(1-7) and tryptophan, as well as alterations in other peptide levels, which all may contribute to observed phenotypes. ACE2 −/y mice and also heterozygous female ACE2 +/− mice were more susceptible to cardiac injury induced by pressure overload, AngII infusion, or diabetes [69, 109, 115, 125] and ACE2 −/y mice developed cardiac abnormalities at older age [17] probably due to an increased level of Ang II [68] . However, the spontaneous appearance of cardiac alterations could not be confirmed by another group and therefore remains controversial [31, 32, 125] . However, obesity-induced epicardial inflammation was worsened and caused cardiac dysfunction in ACE2 −/y mice [70] . Furthermore, in heart and skeletal muscle, ACE2 was involved in training-induced physiological hypertrophy [59] . There were also inconsistencies in the reports about hypertension in ACE2 −/y mice, but it is now accepted that this phenotype is depending on the strain of mice appearing in C57BL/6 and FVB/N but not in 129 mice [32, 38, 77, 101] . ACE2-deficient mice on C57BL/6 background even developed a pre-ecclampsia-like syndrome when pregnant [8] and placental hypoxia and uterine artery dysfuncion caused fetal growth restriction in these animals [124] . In ACE2 −/− female mice, estrogen cannot inhibit obesity-induced hypertension in contrast to wild-type controls [114] . We and others have described AngII-dependent endothelial dysfunction in ACE2-deficient mice [49, 77] , which probably mediated the prohypertensive phenotype. However, an increased sympathetic outflow may have also contributed [119] . On the other hand, ACE2 also degrades the vasodilator apelin peptides which consequently accumulate in ACE2 −/y mice and counteract the effects on the RAS [110] . Nevertheless, there were several other vascular effects of genetic ACE2-deletion such as a worsening of atherosclerosis and aortic aneurysm in apolipoprotein E (ApoE)-and low-density lipoprotein receptor-deficient mice [63, 81, 99, 100] and an increased neointima formation after vascular injury [81] , to which the endothelial dysfunction was a major contributor.

In double knockout mice for ACE2 and ApoE, also the renal injury induced by atherosclerosis was aggravated [38] . Moreover, ACE2 −/y mice spontaneously developed glomerulosclerosis in older age [67] and were more susceptible to renal ischemia/reperfusion injury due to increased cytokine expression, inflammation, and oxidative stress [23] . Accordingly, genetic ACE2 deficiency led to accelerated nephropathy in streptozotocin (STZ)-induced and Akita diabetic mice [91, 115] . Furthermore, knockout mice for ACE2 infused with AngII showed enhanced collagen I deposition in renal glomeruli and expression of genes related to fibrosis, such as smooth muscle actin, transforming growth factor β (TGF-β), and procollagen I, probably through activation of ERK1/2 and enhancement of protein kinase C levels [133] . ACE2-deficient mice also showed a worse outcome in shock-induced kidney injury [127] , chronic hepatic injury [66] , liver steatosis [12, 64] , and ceruleininduced pancreatitis [48] .

The lung is a major site of ACE2 expression. Accordingly, ACE2 −/y mice exhibited an aggravated pathogenesis of lung injury induced by cigarette smoke, air pollution, bleomycin, influenza virus or respiratory syncytial virus [30, 36, 46, 80, 134] , of pulmonary hypertension [129] , and of acute respiratory distress syndrome [37] . In most of these injury models, the increased oxidative stress observed in kidneys [116] , livers [12, 64] , and vessels [71] of ACE2 −/y mice contributed to the exacerbation.

ACE2 in the gut with its collectrin domain is part of the amino acid uptake system and, therefore, mice lacking this protein showed reduced tryptophan in the blood, an altered gut microflora, and intestinal inflammation [34, 95] . These results were recently confirmed in a novel ACE2-deficient mouse model on an outbred genetic background generated by transcription-activator-like effector nucleases (TALEN) [47] . Whether the collectrin-domain-dependent effects contributed to the metabolic alterations shown in ACE2-deficient mice, such as insulin resistance and impaired glucose homeostasis [12, 63] in particular under a high-fat diet [15, 50, 90, 92, 123] needs still to elucidated [7] . However, in the liver, the carboxypeptidase function of ACE2 was more relevant for these metabolic effects since they could be ameliorated by Ang-(1-7) infusion [12] .

ACE2 in the brain also influences behavior since ACE2-deficient mice showed impaired performance in cognition and memory tests [111] .

Recently, it was discovered that serine 680 of mouse ACE2 is phosphorylated by AMP kinase, leading to increased stability of the protein. When this phosphorylation was mimicked (S680D) in knockin mice by CRISPR/Cas9 technology, the resulting animals were partially resistant to a pulmonary hypertension model [129] .

ACE2 knockout rats have recently been established using TALEN technology [130] . These animals exhibited cardiac hypertrophy and impaired heart function; however, their blood pressure was not reported. Therefore, it remains unclear whether the cardiac effects are direct or caused by hypertension.

In order to allow tissue-specific activation of ACE2 expression, the mouse ACE2 coding region was knocked into the Rosa26 locus of mice with a Stop-lox cassette in front of it, which inhibits transcription. This cassette can be removed by Crerecombinase expression and then ACE2 gets highly expressed in the cells expressing Cre-recombinase. When Cre-recombinase was expressed in the germline, ubiquitously ACE2 overexpressing mice resulted, which were protected from postinfarction cardiac dysfunction [75] and exhibited less anxiety-related behavior [107] . The same behavioral effects were also observed when the gene was only activated in CRH (corticotropin-releasing hormone) expressing cells using the corresponding Cre-recombinase-expressing mouse for breeding with the ACE2/Rosa26 animals [108] .

Human ACE2 is hijacked by the SARS virus as a receptor to enter cells. In order to create a model for this disease, mice were "humanized" by several groups by inserting human ACE2 transgenes in their genome either using the ACE2 promoter itself [126] , the ubiquitously active cytomegalovirus (CMV) promoter [102, 128] , or the airwayspecific cytokeratin 18 promoter [53, 62] . These animals were also suitable for studies on the role of ACE2 in other diseases and therefore the first model was tested in a kidney injury model and showed a protected phenotype [127] . Moreover, it was shown to be protected from AngII-induced hypertension and myocardial fibrosis [109] .

When human ACE2 was overexpressed in hearts of transgenic mice, surprisingly ventricular tachycardia and sudden death was observed accompanied by a dysregulation of connexin expression [21] . Apelin, which is also a substrate for ACE2 [104] , may in this case be lacking and this deficiency may have caused the cardiac dysfunction [41] .

When human ACE2 was overexpressed in kidneys of transgenic mice, particularly in podocytes using the nephrin promoter, the animals became protected from diabetes-induced renal injury [61] . The authors provided evidence that the relative amounts of AngII and Ang-(1-7) are critical for the phenotype by increased AngII upregulating TGF-β.

When human ACE2 was overexpressed in brains of transgenic mice using the synapsin promoter, a protective phenotype is observed for several cardiovascular diseases. This included hypertension induced by peripheral infusions of AngII [26] and by desoxycorticosterone acetate (DOCA)/salt treatment [118] , cardiac hypertrophy elicited by AngII [25] , coronary ligation-induced chronic heart failure [120] , and stroke triggered by middle cerebral artery occlusion [14, 132] . In another model, the ACE2 transgene was flanked by loxP sites and it could therefore be specifically deleted in distinct brain regions by the local injection of Cre-recombinaseexpressing adeno-associated viruses to assess the relevance of these areas for the blood pressure increase after DOCA/salt treatment. Such experiments revealed the paraventricular nucleus of the hypothalamus and the subfornical organ as important but not exclusive contributors to hypertension development [117] . The shift in the balance between Ang-(1-7) and AngII in brain regions important for cardiovascular control modulated local NO and ROS production as well as cyclooxygenase-mediated neuroinflammation [97] and likely caused the beneficial effects of ACE2 in the brain. Accordingly, the AngII-dependent deleterious effects on brain tissues observed in double transgenic mice expressing human angiotensinogen and human renin were mitigated in triple transgenic animals additionally expressing human ACE2 [14, 131] .

When we overexpressed human ACE2 in vascular smooth muscle of transgenic rats of the spontaneously hypertensive stroke-prone (SHRSP) strain using the smooth muscle myosin heavy chain promoter, blood pressure was significantly reduced [79] . This confirmed a study postulating that reduced ACE2 is an important genetic determinant for hypertension in this strain [17] . Reduced blood pressure was accompanied by decreased oxidative stress and improved endothelial function [79] .

When we generated Mas-deficient (Mas −/− ) mice, it was not yet known that it is the receptor for Ang-(1-7) [105] . Therefore, phenotyping concentrated on the brain as major Mas-expressing organ. Male (but not female [106] ) Mas-deficient mice showed increased anxiety-like behavior and long-term potentiation (LTP) in the hippocampus [105] . Surprisingly, despite the improved LTP, object recognition memory was impaired [43] . However, Mas −/− mice showed delayed extinction of fear memory [42] and were protected from cognitive impairments induced by ischemia but only in the presence of the AngII AT2 receptor [35] supporting a role of the dimerization of both receptors in brain function [44] .

After our discovery that Mas is the receptor for Ang-(1-7) [85] , we performed comprehensive cardiovascular phenotyping. Mas-deficient mice on the C57BL/6 background exhibited spontaneous cardiac fibrosis and dysfunction [13, 72, 83, 113] . Increased oxidative stress and endothelial dysfunction were observed on all genetic backgrounds studied (C57BL/6 and FVB/N) [33, 78, 121] , but only resulted in hypertension in FVB/N mice. Possibly, an autonomic dysbalance in Mas −/− mice also contributed to the increased blood pressure [76] . Moreover, regional blood flow and local vascular resistance were differentially altered in different tissues of Mas −/− mice [10] , which may also be the cause for the increased vascular resistance in the corpus cavernosum and the resulting erectile dysfunction observed in these mice [29] .

Mas −/− mice showed an impaired renal function with increased urinary volume and proteinuria [74] . However, Esteban and coworkers found that Mas knockout mice presented an attenuation of renal damage in the unilateral ureteral obstruction and in the renal ischemia/reperfusion model [22] . The authors reported that Ang-(1-7) infusion led to NF-κB activation and inflammation via Mas. In contrast, Kim et al. showed protective effects of Ang-(1-7) infusion in the same model [40] and no aggravation of renal injury produced by kidney ischemia/reperfusion was observed in Mas −/− mice [6] . Moreover, Mas −/− mice were protected from adriamycin-induced renal injury, again confirming the protective actions of the ACE2/ Ang-(1-7)/Mas axis of the RAS in the kidney [94] . The discrepancy between the studies remained unresolved, but anti-inflammatory and protective actions of Mas have repeatedly been described also in other organs: Ang-(1-7) protected from intracranial aneurysm only in wild-type but not in Mas −/− mice [73] . Mas deficiency promoted atherosclerosis and autoimmune encephalitis by affecting macrophage polarization and migration [33] and by increasing vascular intima proliferation [2] . The effects on macrophages and other leukocytes were probably also the reason for the higher susceptibility of Mas −/− mice in an endotoxic shock model [65, 96] . Moreover, Mas −/− mice presented aggravated inflammatory pain [16] and allergic pulmonary inflammation [51] .

Mas −/− mice are also a model for metabolic syndrome since they developed metabolic abnormalities, such as type 2 diabetes mellitus and dyslipidemia [88] , besides their hypertensive phenotype. On the mechanistic level, this was accompanied by decreased PPARγ expression in fat tissue [52] and a change in the relative amounts of α and β cells in pancreatic islets [24] . Ang-(1-7), mainly via Mas, stimulated insulin secretion from β cells [82] . Furthermore, Mas −/− mice developed liver steatosis when bred with ApoE-deficient mice [93] and Mas −/− female mice were more susceptible to obesity-induced hypertension [113] . Ang-(1-7) and Mas were involved in vascular repair, which is deficient in diabetes, and hindlimb ischemia-induced progenitor cell mobilization was absent in Mas −/− mice [103] .

In skeletal muscle, Ang-(1-7) and Mas protected from atrophy since Mas −/− mice were more susceptible to a Duchenne muscular dystrophy model (mdx) [1] and to immobilization-induced atrophy [56] .

Mas knockout rats have been established using Zinc-finger nuclease technology but their phenotype is only partially reported on the Rat Genome Database website (https://rgd.mcw.edu/rgdweb/report/gene/main.html?id=3049).

Transgenic mice overexpressing Mas in the retina under the control of the opsin promoter developed degeneration of photoreceptors [122] . This surprising phenotype may have been caused by the ligand-independent constitutive activity of Mas [4] causing proliferative effects in cells when the gene is overexpressed.

The group of Timothy Reudelhuber invented a method to express and secrete peptides from an artificial protein without the need of specific proteases in transgenic animals [54, 55] . Using this method, Ang-(1-7) was overexpressed in transgenic rats (TGR(A1-7)3292) using the CMV promoter [28] . These animals mainly expressed the peptide in the testis, which nevertheless significantly increased plasma levels of Ang-(1-7). As a consequence, total peripheral resistance was decreased together with increases in the blood flow to several organs. Nonetheless, the animals remained normotensive, probably since they exhibited an improved pumping function of the heart [11] . These cardiac effects also protected the heart from pressure and ischemia-induced damage [84] as well as from DOCA-induced diastolic dysfunction [19] . A part of these effects may be due to alterations in autonomic regulation observed in these rats [18] . The increased levels of plasma Ang-(1-7) exerted antinatriuretic actions in the kidney resulting in reduced urinary flow and increased urinary osmolality [28] . Furthermore, TGR(A1-7)3292 rats exhibited metabolic improvements such as decreased plasma lipid levels, improved glucose tolerance, less fat tissue, decreased lipogenesis, and less cafeteria-diet-induced obesity [9, 57, 87, 89] . Moreover, these rats presented a reduction in anxiety-like behavior [39] and in the response to stress [60] .

We also generated transgenic mice and rats expressing the Ang-(1-7) release protein specifically in the heart using the α cardiac myosin heavy chain promoter. Both lines showed a slightly improved heart function at baseline and were protected from cardiac hypertrophy [27, 54] , but, interestingly, not from myocardial infarction [112] .

As summarized in this chapter, several genetically altered rat and mouse models have been generated changing the expression of components of the ACE2/Ang-(1-7)/Mas axis of the RAS (Table 1) . With the help of these models, physiological and pathophysiological functions of this axis have been elucidated. Nevertheless, novel models are warranted with cell-type-specific deficiency of ACE2 or Mas to further delineate their tissue-specific effects. The already collected findings are the basis for the development of novel therapeutic strategies for cardiovascular and metabolic diseases by targeting ACE2 or Mas [86, 98] .

Restoration of muscle strength in dystrophic muscle by angiotensin-1-7 through inhibition of TGF-beta signalling

Increased aortic intimal proliferation due to MasR deletion in vitro

Rat models of cardiovascular diseases

Mas and its related G proteincoupled receptors

Transgenic animals in cardiovascular disease research

Simoes e Silva AC, and Teixeira MM. Renoprotective effects of AVE0991, a nonpeptide Mas receptor agonist, in experimental acute renal injury

ACE2 deficiency shifts energy metabolism towards glucose utilization

Angiotensin-converting enzyme 2 deficiency is associated with impaired gestational weight gain and fetal growth restriction

Decreased hepatic gluconeogenesis in transgenic rats with increased circulating angiotensin-(1-7)

Altered regional blood flow distribution in Mas-deficient mice

Expression of an angiotensin-(1-7)-producing fusion protein in rats induced marked changes in regional vascular resistance

The ACE2/Ang-(1-7)/Mas axis can inhibit hepatic insulin resistance

Effects of genetic deletion of angiotensin-(1-7) receptor Mas on cardiac function during ischemia/reperfusion in the isolated perfused mouse heart

Neuronal over-expression of ACE2 protects brain from ischemia-induced damage

High-fat diet-induced glucose dysregulation is independent of changes in islet ACE2 in mice

Participation of AT1 and Mas receptors in the modulation of inflammatory pain

Angiotensin-converting enzyme 2 is an essential regulator of heart function

Improved cardiovascular autonomic modulation in transgenic rats expressing an Ang-(1-7)-producing fusion protein

Beneficial effects of angiotensin-(1-7) against deoxycorticosterone acetateinduced diastolic dysfunction occur independently of changes in blood pressure

Heart block, ventricular tachycardia, and sudden death in ACE2 transgenic mice with downregulated connexins

Angiotensin-(1-7) and the g proteincoupled receptor MAS are key players in renal inflammation

Loss of ACE2 exacerbates murine renal ischemia-reperfusion injury

Glucagon-producing cells are increased in Mas-deficient mice

Angiotensin-converting enzyme 2 over-expression in the central nervous system reduces angiotensin-II-mediated cardiac hypertrophy

Brain-selective overexpression of human angiotensin-converting enzyme type 2 attenuates neurogenic hypertension

Attenuation of isoproterenol-induced cardiac fibrosis in transgenic rats harboring an angiotensin-(1-7)-producing fusion protein in the heart

Renal functions in transgenic rats expressing an angiotensin-(1-7)-producing fusion protein

The vasodilator angiotensin-(1-7)-Mas axis plays an essential role in erectile function

Angiotensin-converting enzyme 2 inhibits lung injury induced by respiratory syncytial virus

Altered blood pressure responses and normal cardiac phenotype in ACE2-null mice

Angiotensin-converting enzyme 2 gene targeting studies in mice: mixed messages

Role of the receptor Mas in macrophage-mediated inflammation in vivo

ACE2 links amino acid malnutrition to microbial ecology and intestinal inflammation

Beneficial Effect of Mas Receptor Deficiency on Vascular Cognitive Impairment in the Presence of Angiotensin II Type 2 Receptor

Alternative roles of STAT3 and MAPK signaling pathways in the MMPs activation and progression of lung injury induced by cigarette smoke exposure in ACE2 knockout mice

Angiotensin-converting enzyme 2 protects from severe acute lung failure

Deletion of angiotensin-converting enzyme 2 exacerbates renal inflammation and injury in apolipoprotein E-deficient mice through modulation of the nephrin and TNF-alpha-TNFRSF1A signaling

Reduced anxiety-like behavior in transgenic rats with chronically overproduction of angiotensin-(1-7): role of the Mas receptor

Angiotensin-(1-7) attenuates kidney injury due to obstructive nephropathy in rats

Impaired heart contractility in Apelin gene-deficient mice associated with aging and pressure overload

Angiotensin-(1-7)/Mas axis modulates fear memory and extinction in mice

Angiotensin-(1-7)/Mas axis integrity is required for the expression of object recognition memory

Evidence for Heterodimerization and functional interaction of the angiotensin type 2 receptor and the receptor MAS

Angiotensin-converting enzyme 2 is a functional receptor for the SARS coronavirus

Instillation of particulate matter 2.5 induced acute lung injury and attenuated the injury recovery in ACE2 knockout mice

Generation of outbred Ace2 knockout mice by RNA transfection of TALENs displaying colitis reminiscent pathophysiology and inflammation

Angiotensin-converting enzyme (ACE and ACE2) imbalance correlates with the severity of cerulein-induced acute pancreatitis in mice

Angiotensin converting enzyme-2 confers endothelial protection and attenuates atherosclerosis

The angiotensin-converting enzyme 2/angiotensin (1-7)/ Mas axis protects the function of pancreatic beta cells by improving the function of islet microvascular endothelial cells

Chronic allergic pulmonary inflammation is aggravated in angiotensin-(1-7) Mas receptor knockout mice

Angiotensin-(1-7) Masreceptor deficiency decreases peroxisome proliferator-activated receptor gamma expression in adipocytes

Lethal infection of K18-hACE2 mice infected with severe acute respiratory syndrome coronavirus

Angiotensin 1-7 blunts hypertensive cardiac remodeling by a direct effect on the heart

Tissue targeting of angiotensin peptides

Angiotensin-(1-7) attenuates disuse skeletal muscle atrophy in mice via its receptor

Long-term effects of angiotensin-(1-7) on lipid metabolism in the adipose tissue and liver

Genetically altered animals in the study of the metabolic functions of peptide hormone systems

Effects of ACE2 deficiency on physical performance and physiological adaptations of cardiac and skeletal muscle to exercise

Chronic overexpression of angiotensin-(1-7) in rats reduces cardiac reactivity to acute stress and dampens anxious behavior

Podocyte-specific overexpression of human angiotensin-converting enzyme 2 attenuates diabetic nephropathy in mice

Severe acute respiratory syndrome coronavirus infection causes neuronal death in the absence of encephalitis in mice transgenic for human ACE2

Loss of angiotensin-converting enzyme 2 leads to impaired glucose homeostasis in mice

CD36/ Sirtuin 1 Axis impairment contributes to hepatic steatosis in ACE2-deficient mice

Mas receptor deficiency exacerbates lipopolysaccharide-induced cerebral and systemic inflammation in mice

Angiotensin-converting-enzyme 2 inhibits liver fibrosis in mice

Loss of angiotensin-converting enzyme-2 leads to the late development of angiotensin II-dependent glomerulosclerosis

Angiotensin II-mediated oxidative stress and inflammation mediate the age-dependent cardiomyopathy in ACE2 null mice

Cardioprotective effects mediated by angiotensin II type 1 receptor blockade and enhancing angiotensin 1-7 in experimental heart failure in angiotensin-converting enzyme 2-null mice

ACE2 deficiency worsens Epicardial adipose tissue inflammation and cardiac dysfunction in response to diet-induced obesity

Angiotensin-converting enzyme 2 is a critical determinant of angiotensin II-induced loss of vascular smooth muscle cells and adverse vascular remodeling

Endothelial dysfunction through genetic deletion or inhibition of the G protein-coupled receptor Mas: a new target to improve endothelial function

Angiotensin 1-7 reduces mortality and rupture of intracranial aneurysms in mice

Simoes e Silva AC. Genetic deletion of the angiotensin(1-7) receptor Mas leads to glomerular hyperfiltration and microalbuminuria

Angiotensin-converting enzyme 2 inhibits high-mobility group box 1 and attenuates cardiac dysfunction post-myocardial ischemia

Increased vascular sympathetic modulation in mice with Mas receptor deficiency

Genetic deletion of ACE2 induces vascular dysfunction in C57BL/6 mice: role of nitric oxide imbalance and oxidative stress

Ablation of angiotensin (1-7) receptor Mas in C57Bl/6 mice causes endothelial dysfunction

Transgenic ACE2 overexpression in vessels of SHRSP rats reduces blood pressure and improves endothelial function

Angiotensin converting enzyme 2 abrogates bleomycininduced lung injury

Deletion of angiotensin-converting enzyme 2 promotes the development of atherosclerosis and arterial neointima formation

The angiotensin-(1-7)/Mas Axis improves pancreatic beta-cell function in vitro and in vivo

Impairment of in vitro and in vivo heart function in angiotensin-(1-7) receptor Mas knockout mice

Expression of an angiotensin-(1-7)-producing fusion protein produces cardioprotective effects in rats

Angiotensin-(1-7) is an endogenous ligand for the G-protein coupled receptor Mas

The ACE2/angiotensin-(1-7)/MAS Axis of the renin-angiotensin system: focus on angiotensin

Improved lipid and glucose metabolism in transgenic rats with increased circulating angiotensin-(1-7)

Mas deficiency in FVB/N in mice produces marked changes in lipid and glycemic metabolism

Lack of weight gain after angiotensin AT1 receptor blockade in diet-induced obesity is partly mediated by an angiotensin-(1-7)/Mas-dependent pathway

Angiotensinconverting enzyme 2 regulates mitochondrial function in pancreatic beta-cells

Loss of ACE2 accelerates time-dependent glomerular and tubulointerstitial damage in streptozotocin-induced diabetic mice

ACE2 deficiency reduces beta-cell mass and impairs beta-cell proliferation in obese C57BL/6 mice

Mas receptor deficiency is associated with worsening of lipid profile and severe hepatic steatosis in ApoE knockout mice

Beneficial effects of the activation of the Angiotensin-(1-7) MAS receptor in a murine model of adriamycin-induced nephropathy

Defective intestinal amino acid absorption in Ace2 null mice

Receptor Mas protects mice against hypothermia and mortality induced by endotoxemia

Brain-targeted angiotensin-converting enzyme 2 overexpression attenuates neurogenic hypertension by inhibiting cyclooxygenase-mediated inflammation

Emerging drugs which target the reninangiotensin-aldosterone system

Angiotensin-converting enzyme 2 decreases formation and severity of angiotensin II-induced abdominal aortic aneurysms

Genetic Ace2 deficiency accentuates vascular inflammation and atherosclerosis in the ApoE knockout mouse

Angiotensin-converting enzyme 2 mediates hyperfiltration associated with diabetes

Severe acute respiratory syndrome coronavirus infection of mice transgenic for the human angiotensin-converting enzyme 2 virus receptor

Reversal of bone marrow Mobilopathy and enhanced vascular repair by Angiotensin-(1-7) in diabetes

Hydrolysis of biological peptides by human angiotensin-converting enzyme-related carboxypeptidase

Sustained long term potentiation and anxiety in mice lacking the Mas protooncogene

Sex specific behavioural alterations in Mas-deficient mice

Increasing brain angiotensin converting enzyme 2 activity decreases anxiety-like behavior in male mice by activating central Mas receptors

Coupling corticotropin-releasinghormone and angiotensin converting enzyme 2 dampens stress responsiveness in male mice

Protective role of ACE2-Ang-(1-7)-Mas in myocardial fibrosis by downregulating KCa3.1 channel via ERK1/2 pathway

Angiotensin-converting enzyme 2 metabolizes and partially inactivates Pyr-Apelin-13 and Apelin-17: physiological effects in the cardiovascular system

Deficiency of angiotensinconverting enzyme 2 causes deterioration of cognitive function

Circulating rather than cardiac angiotensin-(1-7) stimulates cardioprotection after myocardial infarction

Differential effects of Mas receptor deficiency on cardiac function and blood pressure in obese male and female mice

Administration of 17beta-estradiol to ovariectomized obese female mice reverses obesity-hypertension through an ACE2-dependent mechanism

Loss of angiotensin-converting enzyme-2 (Ace2) accelerates diabetic kidney injury

ACE2 deficiency increases NADPH-mediated oxidative stress in the kidney

Brain ACE2 overexpression reduces DOCA-salt hypertension independently of endoplasmic reticulum stress

Brain angiotensin-converting enzyme type 2 shedding contributes to the development of neurogenic hypertension

ACE2-mediated reduction of oxidative stress in the central nervous system is associated with improvement of autonomic function

Brain-selective overexpression of angiotensinconverting enzyme 2 attenuates sympathetic nerve activity and enhances baroreflex function in chronic heart failure

Endothelial dysfunction and elevated blood pressure in Mas gene-deleted mice

Degeneration of cone photoreceptors induced by expression of the Mas1 protooncogene

Activation of ACE2/angiotensin (1-7) attenuates pancreatic beta cell dedifferentiation in a high-fat-diet mouse model

Uterine artery dysfunction in pregnant ACE2 knockout mice is associated with placental hypoxia and reduced umbilical blood flow velocity

Deletion of angiotensin-converting enzyme 2 accelerates pressure overload-induced cardiac dysfunction by increasing local angiotensin II

Mice transgenic for human angiotensin-converting enzyme 2 provide a model for SARS coronavirus infection

Role of angiotensin-converting enzyme (ACE and ACE2) imbalance on tourniquet-induced remote kidney injury in a mouse hindlimb ischemia-reperfusion model

Differential virological and immunological outcome of severe acute respiratory syndrome coronavirus infection in susceptible and resistant transgenic mice expressing human angiotensin-converting enzyme 2

AMPK phosphorylation of ACE2 in endothelium mitigates pulmonary hypertension

The sirtuin 6 prevents angiotensin II-mediated myocardial fibrosis and injury by targeting AMPK-ACE2 signaling

Activation of the ACE2/Ang-(1-7)/Mas pathway reduces oxygen-glucose deprivationinduced tissue swelling, ROS production, and cell death in mouse brain with angiotensin II overproduction

Angiotensin converting enzyme 2/Ang-(1-7)/Mas axis protects brain from ischemic injury with a tendency of age-dependence

Prevention of angiotensin II-mediated renal oxidative stress, inflammation, and fibrosis by angiotensin-converting enzyme 2

Angiotensinconverting enzyme 2 protects from lethal avian influenza a H5N1 infections