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Renin-angiotensin-aldosterone system inhibitors (RAAS-I) have been shown to prolong overall survival in patients with liver metastasized colorectal cancer in combination with antiangiogenic treatment. The effects of RAAS-I combined with neoadjuvant chemotherapy on colorectal cancer liver metastasis remain unexplored. We aimed to study the response of patients undergoing liver resection to RAAS-I in combination with neoadjuvant therapy to elucidate their potential benefits. Between February 2005 and May 2012, 62 patients fulfilled the inclusion criteria for distant metastasis (cM1) and comparable computed tomography or magnetic resonance tomography scans in the Picture Archiving Communication System of our center before and after neoadjuvant chemotherapy. Follow-up data and clinicopathological characteristics were collected from a prospective database and retrospectively investigated. The chemotherapeutic response to liver metastasis was evaluated according to the Response Evaluation Criteria in Solid Tumors criteria 1.1. Comparing the average reduction of measured lesions, a significant response to chemotherapy was detected in the patients receiving RAAS-I (n = 24) compared to those who did not (n = 38) (P = 0.031). Interestingly, the effect was more distinctive when the size reduction was compared between high responses with more than 50% size reduction of all measured lesions (P = 0.011). In the subgroup analysis of patients receiving bevacizumab treatment, high responses to chemotherapy were observed only in the RAAS-I cohort (28.6% versus 0%, P = 0.022). For neoadjuvantly treated patients, concomitant antihypertensive treatment with RAAS-I showed a higher total size reduction of liver metastasis as a sign of treatment response, especially in combination with antiangiogenic treatment with bevacizumab. [ABSTRACT FROM AUTHOR]

• Metabolic syndrome (MetS) and Parkinson are related but mechanistic links are unknown. • Rat models and patients of MetS show increased levels of AT1 receptor autoantibodies. • Increase in serum AT1 autoantibodies induced blood–brain barrier disruption. • AT1 autoantibodies increase nigral proinflammatory activity and neurodegeneration. • Angiotensin receptor autoantibodies are a link between MetS and Parkinson's disease. The metabolic syndrome has been associated to chronic peripheral inflammation and related with neuroinflammation and neurodegeneration, including Parkinson's disease. However, the responsible mechanisms are unclear. Previous studies have involved the brain renin-angiotensin system in progression of Parkinson's disease and the angiotensin receptor type 1 (AT1) has been recently revealed as a major marker of dopaminergic vulnerability in humans. Dysregulation of tissue renin-angiotensin system is a key common mechanism for all major components of metabolic syndrome. Circulating AT1 agonistic autoantibodies have been observed in several inflammation-related peripheral processes, and activation of AT1 receptors of endothelial cells, dopaminergic neurons and glial cells have been observed to disrupt endothelial blood -brain barrier and induce neurodegeneration, respectively. Using a rat model, we observed that metabolic syndrome induces overactivity of nigral pro-inflammatory renin-angiotensin system axis, leading to increase in oxidative stress and neuroinflammation and enhancing dopaminergic neurodegeneration, which was inhibited by treatment with AT1 receptor blockers (ARBs). In rats, metabolic syndrome induced the increase in circulating levels of LIGHT and other major pro-inflammatory cytokines, and 27-hydroxycholesterol. Furthermore, the rats showed a significant increase in serum levels of proinflammatory AT1 and angiotensin converting enzyme 2 (ACE2) autoantibodies, which correlated with levels of several metabolic syndrome parameters. We also found AT1 and ACE2 autoantibodies in the CSF of these rats. Effects of circulating autoantibodies were confirmed by chronic infusion of AT1 autoantibodies, which induced blood–brain barrier disruption, an increase in the pro-inflammatory renin-angiotensin system activity in the substantia nigra and a significant enhancement in dopaminergic neuron death in two different rat models of Parkinson's disease. Observations in the rat models, were analyzed in a cohort of parkinsonian and non-parkinsonian patients with or without metabolic syndrome. Non-parkinsonian patients with metabolic syndrome showed significantly higher levels of AT1 autoantibodies than non-parkinsonian patients without metabolic syndrome. However, there was no significant difference between parkinsonian patients with metabolic syndrome or without metabolic syndrome, which showed higher levels of AT1 autoantibodies than non-parkinsonian controls. This is consistent with our recent studies, showing significant increase of AT1 and ACE2 autoantibodies in parkinsonian patients, which was related to dopaminergic degeneration and neuroinflammation. Altogether may lead to a vicious circle enhancing the progression of the disease that may be inhibited by strategies against production of these autoantibodies or AT1 receptor blockers (ARBs). [ABSTRACT FROM AUTHOR]

The renin-angiotensin system (RAS) is a key hormonal system. In recent years, the functional analysis of the novel axis of the RAS (ACE2/Ang-(1–7)/Mas receptor) revealed that its activation can become protective against several pathologies, including cardiovascular diseases. Mas knockout mice (Mas-KO) represent an important tool for new investigations. Indeed, extensive biological research has focused on investigating the functional implications of Mas receptor deletion. However, although the Mas receptor was identified in neonatal cardiomyocytes and also in adult ventricular myocytes, only few reports have explored the Ang-(1–7)/Mas signaling directly in cardiomyocytes to date. This study investigated the implication of Mas receptor knockout to the cytokine profile, energy metabolism, and electrical properties of mice-isolated cardiomyocytes. Here, we demonstrated that Mas-KO mice have modulation in some cytokines, such as G-CSF, IL-6, IL-10, and VEGF in the left ventricle. This model also presents increased mitochondrial number in cardiomyocytes and a reduction in the myocyte diameter. Finally, Mas-KO cardiomyocytes have altered action potential modulation after diazoxide challenge. Such electrical finding was different from the data showed for the TGR(A1-7)3292 (TGR) model, which overexpresses Ang-(1–7) in the plasma by 4.5, used by us as a control. Collectively, our findings exemplify the importance of understanding the ACE2/Ang-(1–7)/Mas pathway in cardiomyocytes and heart tissue. The Mas-KO mice model can be considered an important tool for new RAS investigations. • Mas knockout mice (Mas-KO) have modulation in cytokines from the left ventricle. • Mas-KO animals present increased mitochondrial number in cardiomyocytes. • Mas-KO cardiomyocytes have altered action potential modulation. [ABSTRACT FROM AUTHOR]

The worldwide pandemic of Coronavirus disease 2019 (COVID-19) is triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and further worsened by the emergence of a variety of SARS-CoV-2 variants. Angiotensin-converting enzyme 2 (ACE2), a carboxypeptidase of M32 family, serves as the receptor of SARS-CoV-2 and key regulator of host renin-angiotensin system (RAS), both of which are mainly mediated via the carboxypeptidase domain of ACE2 (sACE2) or its activity. sACE2 is thus promising in the treatment of COVID-19 but unfortunately weakened by its unstrigent substrate preference and complex interplay with host RAS. B38-CAP, an isoenzyme of ACE2, partically compensates these defects but still encounters the problem related to carboxypeptidase activity and specificity. In this study, we firstly determined the crystal structure of B38-CAP at a resolution of 2.44 Å which exists in dimeric form with the non-crystallographic two-fold axis being in coincidence with the crystallographic two-fold axis. Further structural analysis revealed the structural conservatism feature among M32 family, particularly the catalytic core and moreover lead us to hypothesize that conformational flexibility might play an pivotal role in the catalysis of B38-CAP and ACE2. The work provided here presents key features of the M32 family carboxypeptidase and provides structural basis for further development of B38-CAP-based anti-SARS-CoV-2 drugs. • The dimeric structure of B38-CAP, an isoenzyme of carboxypeptidase ACE2, is determined at a resolution of 2.44 Å. • Structural rather than sequential conservatism is shared by B38-CAP and ACE2. • The catalytic core is highly conservative between B38-CAP and ACE2. • Conformational flexibility of B38-CAP and ACE2 might contribute to the difference in their carboxypeptidase activity. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases are a serious threat to human health, especially in the elderly. Vascular aging makes people more susceptible to cardiovascular diseases due to significant dysfunction or senescence of vascular cells and maladaptation of vascular structure and function; moreover, vascular aging is currently viewed as a modifiable cardiovascular risk factor. To emphasize the relationship between senescent cells and vascular aging, we first summarize the roles of senescent vascular cells (endothelial cells, smooth muscle cells and immune cells) in the vascular aging process and inducers that contribute to cellular senescence. Then, we present potential strategies for directly targeting senescent cells (senotherapy) or preventively targeting senescence inducers (senoprevention) to delay vascular aging and the development of age-related vascular diseases. Finally, based on recent research, we note some important questions that still need to be addressed in the future. The relationships among cellular senescence inducers, senescent cells and vascular aging. Telomere-dependent replicative senescence and stress-induced premature senescence have different senescence inducers. These inducers comprise a complicated network and promote cell senescence in aortas. Senescent vascular cells lead to typical pathological changes of vascular aging by abnormal function and molecular expression, which further contribute to related vascular diseases. Cell senescence and other pathological changes induced the abnormalities in vascular structure and function, which are direct manifestations of vascular aging and related diseases. More details are provided in the main text. Abbreviation: ECs: Endothelium cells; ECM: Extracellular matrix; IIS: Impaired immunosurveillance; RAAS: Renin-angiotensin-aldosterone system; SASP: Senescence associated secretory phenotype; VSMCs: Vascular smooth muscle cells. [Display omitted] • Vascular aging is currently viewed as a modifiable cardiovascular risk factor. • Vascular cells senescence contributes to the progression of vascular aging along with age-related disorders. • The clearance of senescent cells by senotherapy or senoprevention is a candidate intervention to decelerate vascular aging. [ABSTRACT FROM AUTHOR]

Renin-Angiotensin System (RAS) is a peptidergic system, canonically known for its role in blood pressure regulation. Furthermore, a non-canonical RAS regulates pathophysiological phenomena, such as inflammation since it consists of two main axes: the pro-inflammatory renin/(pro)renin receptor ((P)RR) axis, and the anti-inflammatory angiotensin-converting enzyme 2 (ACE2)/Angiotensin-(1–7) (Ang-(1–7))/Mas Receptor (MasR) axis. Few phytochemicals have shown to exert angiotensinergic and anti-inflammatory effects through some of these axes; nevertheless, anti-inflammatory drugs, such as phytocannabinoids have not been studied regarding this subject. Among phytocannabinoids, β-Caryophyllene stands out as a dietary phytocannabinoid with antiphlogistic activity that possess a unique sesquiterpenoid structure. Although its cannabinergic effect has been studied, its angiotensinergic effect reminds underexplored. This study aims to explore the angiotensinergic effect of β-Caryophyllene on inflammation and stress at a systemic level. After intranasal Lipopolysaccharide (LPS) installation and oral treatment with β-Caryophyllene, the concentration and activity of key RAS elements in the serum, such as Renin, ACE2 and Ang-(1–7), along with the stress hormone corticosterone and pro/anti-inflammatory cytokines, were measured in mice serum. The results show that β-Caryophyllene treatment modified RAS levels by increasing Renin and Ang-(1–7), alongside the reduction of pro-inflammatory cytokines and corticosterone levels. These results indicate that β-Caryophyllene exhibits angiotensinergic activity in favor of anti-inflammation. [Display omitted] • Angiotensinergic effect of β-Caryophyllene is characterized by the increase of serum Renin and Angiotensin-(1–7). • β-Caryophyllene reduces serum pro-inflammatory cytokines as well as the stress hormone corticosterone. • The increase of Angiotensin-(1–7) is positively associated with the increase of IL-10. • β-Caryophyllene does not modify the enzymatic activity of soluble Angiotensin-Converting Enzyme 2. [ABSTRACT FROM AUTHOR]

Alamandine is a peptide hormone belonging to the renin–angiotensin system (RAS). It acts through the Mas-related G-protein coupled receptor type D, MrgD, which is expressed in different tissues, including the brain. In the present study, we hypothesize that a lack of alamandine, through MrgD, could cause the anxiety-like behavior in transgenic rats with low brain angiotensinogen [TGR(ASrAOGEN)680]. Adult male transgenic rats exhibited a significant increase in the latency to feeding time in the novelty suppressed feeding test and a decrease in the percentage of time and entries in the open arms in the elevated plus maze. These effects were reversed by intracerebroventricular infusion of alamandine. Pretreatment with D-Pro7-Ang-(1–7), a Mas and MrgD receptor antagonist, prevented the anxiolytic effects induced by this peptide. However, its effects were not altered by the selective Mas receptor antagonist, A779. In conclusion, our data indicates that alamandine, through MrgD, attenuates anxiety-like behavior in male TGR(ASrAOGEN)680, which reinforces the importance of the counter-regulatory RAS axis as promising target for the treatment of neuropsychiatric disorders. • Alamandine induces anxiolytic effect in male TGR(ASrAOGEN)680 rats. • Alamandine promote anxiolytic effect dependent on MrgD receptor activation. • Mas/MrgD receptors antagonist reversed the anxiolytic effect induced by alamandine. • Selective Mas receptor antagonist did not modify the anxiolytic effect of alamandine. [ABSTRACT FROM AUTHOR]

Klotho is well known as a gene with antiaging properties. It has membrane and soluble forms, providing a unique system that controls various metabolic processes essential to health and disease. Klotho deficiency has been revealed to be associated with various aging-related disorders. Based on its various known and unknown protective properties, upregulating the Klotho gene may be a possible therapeutic and/or preventive approach in aging-related complications. Some agents, such as hormonal compounds, renin-angiotensin system inhibitors, antioxidants, peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists, statins, vitamin D receptor agonists, antioxidants, anti-inflammatory agents, mammalian target of rapamycin (mTOR) signaling inhibitors, and receptor-interacting serine/threonine-protein kinase 1 (RIPK1) inhibitors, can possibly lead to the upregulation and elevation of Klotho levels. Demethylation and deacetylation of the Klotho gene can also be considered other possible Klotho-enhancement methods. Some emerging techniques, such as RNA modifications, gene therapy, gene editing, and exosome therapy, probably have the potential to be applied for increasing Klotho. In the present study, these current and emerging Klotho-enhancement strategies and their underlying mechanisms were comprehensively reviewed, which could highlight some potential avenues for future research. [Display omitted] • Klotho (Kl) is well described as a gene with antiaging properties. • Kl controls a wide range of metabolic processes essential to health and disease. • Kl deficiency is associated with various aging-related disorders (ARD). • Upregulating the Kl gene may be a possible therapeutic approach in ARD. • There are various current and emerging methods to enhance Kl content. [ABSTRACT FROM AUTHOR]

To assess the effects of a ketogenic diet on metabolism and renal fibrosis in spontaneously hypertensive rats. Male spontaneously hypertensive rats (SHRs) and Wistar Kyoto (WKY) rats were randomly divided into a ketogenic diet group and a normal diet group. Blood glucose and metabolites were measured after 4 weeks. Renal autophagy-related protein expression was detected by Western blot, and renal fibrosis was detected by Masson staining. Compared with the normal diet, the ketogenic diet led to significantly decreased glucose tolerance and metabolism; overactivated the renin-angiotensin-aldosterone system; and reduced renal autophagy-related protein expression in SHRs; Masson staining and other experiments showed that the ketogenic diet had no significant effect on hypertensive renal fibrosis. A Ketogenic diet could lead to disorders of glucose and lipid metabolism, increase hypertension by activating the RAAS, reduce renal autophagy levels and aggravate renal parenchymal damage. Therefore, a ketogenic diet, as a kind of natural therapy, should be vigilantly monitored to prevent further damage in patients with hypertension. [Display omitted] • Ketogenic diet led to significantly decreased glucose tolerance and metabolism in spontaneously hypertensive rats. • Ketogenic diet could reduce renal autophagy levels and aggravate renal parenchymal damage in spontaneouslyhypertensive rats. [ABSTRACT FROM AUTHOR]

Pathological cardiac hypertrophy induced by activation of the renin–angiotensin–aldosterone system (RAAS) is one of the leading causes of heart failure. However, in current clinical practice, the strategy for targeting the RAAS is not sufficient to reverse hypertrophy. Here, we investigated the effect of prostaglandin E1 (PGE1) on angiotensin II (AngII)-induced cardiac hypertrophy and potential molecular mechanisms underlying the effect. Adult male C57 mice were continuously infused with AngII or saline and treated daily with PGE1 or vehicle for two weeks. Neonatal rat cardiomyocytes were cultured to detect AngII-induced hypertrophic responses. We found that PGE1 ameliorated AngII-induced cardiac hypertrophy both in vivo and in vitro. The RNA sequencing (RNA-seq) and expression pattern analysis results suggest that Netrin-1 (Ntn1) is the specific target gene of PGE1. The protective effect of PGE1 was eliminated after knockdown of Ntn1. Moreover, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the PGE1-mediated signaling pathway changes are associated with the mitogen-activated protein kinase (MAPK) pathway. PGE1 suppressed AngII-induced activation of the MAPK signaling pathway, and such an effect was attenuated by Ntn1 knockdown. Blockade of MAPK signaling rescued the phenotype of cardiomyocytes caused by Ntn1 knockdown, indicating that MAPK signaling may act as the downstream effector of Ntn1. Furthermore, inhibition of the E-prostanoid (EP) 3 receptor, as opposed to the EP1, EP2, or EP4 receptor, in cardiomyocytes reversed the effect of PGE1, and activation of EP3 by sulprostone, a specific agonist, mimicked the effect of PGE1. In conclusion, PGE1 ameliorates AngII-induced cardiac hypertrophy through activation of the EP3 receptor and upregulation of Ntn1, which inhibits the downstream MAPK signaling pathway. Thus, targeting EP3, as well as the Ntn1–MAPK axis, may represent a novel approach for treating pathological cardiac hypertrophy. [Display omitted] • PGE1 treatment attenuates AngII-induced cardiac hypertrophy without altering blood pressure. • PGE1 mainly targets cardiomyocytes but not cardiac fibroblasts or CMECs. • The activation of EP3 receptor by PGE1 leads to up-regulation of Ntn1, which inhibits the MAPK signaling pathway. • PGE1-EP3 as well as targeting the Ntn1–MAPK axis may represent a novel treatment for pathological cardiac hypertrophy. [ABSTRACT FROM AUTHOR]

Angiotensin II (Ang II), an important component of the renin–angiotensin system (RAS), plays a critical role in the pathogenesis of cardiovascular disorders. In addition, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have been considered as a promising platform for studying personalized medicine for heart diseases. However, whether Ang II can induce the apoptosis of hiPSC-CMs is not known. In this study, we treated hiPSC-CMs with different concentrations of Ang II [0 nM (vehicle as a control), 1 nM, 10 nM, 100 nM, 1 μM, 10 μM, 100 μM, and 1 mM] for various time periods (24 h, 48 h, 6 days, and 10 days) and analyzed the viability and apoptosis of hiPSC-CMs. We found that treatment with 1 mM Ang II for 10 days reduced the viability of hiPSC-CMs by 41% (p = 2.073E-08) and increased apoptosis by 2.74-fold, compared to the control group (p = 6.248E-12). MYOG , which encodes the muscle-specific transcription factor myogenin, was also identified as an apoptosis-suppressor gene in Ang II-treated hiPSC-CMs. Ectopic MYOG expression decreased the apoptosis and increased the viability of Ang II-treated hiPSC-CMs. Further analysis of the RNA sequencing (RNA-seq) data illustrated that myogenin ameliorated Ang II-induced apoptosis of hiPSC-CMs by downregulating the expression of proinflammatory genes. Our findings suggest that Ang II induces the apoptosis of hiPSC-CMs and that myogenin attenuates Ang II-induced apoptosis. • This study examined the effect of Ang II on apoptosis of hiPSC-CMs. • High dose of Ang II reduced viability and increased apoptosis of hiPSC-CMs. • Ectopic expression of MYOG ameliorated the apoptosis induced by Ang II in hiPSC-CMs. • MYOG attenuated the expression of inflammation-related genes in hiPSC-CM. [ABSTRACT FROM AUTHOR]

We believe that, in parallel to the attempts for direct blockade of the SARS-CoV-2 penetration into host cell and repurposing drugs, finding new therapeutic strategies for patients with lung injury or cardiovascular complications/coagulopathies associated with COVID-19 should be paid particular attention. Apelin or its receptor agonists are of great potential treatment for COVID-19 through suppressing angiotensin-converting enzyme (ACE) and angiotensin II (Ang-II) production, as well as, down-regulating angiotensin receptor 1 (AT1R) and ACE2 up-regulation. These drugs have potential to improve acute lung injury and cardiovascular/coagulopathy complications in COVID-19 which are associated with elevated Ang-II/Ang(1–7) ratio. • RAS up-regulation is associated with lung and cardiovascular injuries in COVID-19. • Apelin can suppress ACE and AT1R, and activate ACE2 which is down-regulated by SARS-CoV-2. • Apelin may improve Ang-II-mediated inflammation, thrombosis, and vasoconstriction in COVID-19. • Apelin and its receptor agonists could be trialed in COVID-19 patients. [ABSTRACT FROM AUTHOR]

High-fructose intake induces hypertension via the renal expression of (pro)renin receptor (PRR) that stimulates the expression of sodium/hydrogen exchanger 3, Na/K/2Cl cotransporter 2, and genes of the intrarenal renin-angiotensin system. We hypothesize that maternal high-fructose intake induces hypertension in subsequent generation offspring through activating histone codes on the PRR promoter. Mice dams were offered 20% fructose solution during pregnancy and lactation, while the subsequent 1st to 4th generation offspring were raised without fructose. Blood pressure was measured via tail-cuff method. The mRNA and protein expression were determined using quantitative real-time polymerase chain reaction and western blotting, respectively. Histone modification was evaluated using a chromatin immunoprecipitation assay. Maternal high-fructose intake statistically significantly increased blood pressure in the 1st and 2nd generations of offspring compared to the control group. Expression levels of sodium transporters and PRR were increased in the kidneys of the 1st to 3rd generation offspring. Increased enrichment of active histone codes such as H3Ac and H3K4me2 but decreased enrichment of repressive histone codes such as H3K9me3 and H3K27me3 on the PRR promoter were observed in the 1st to 3rd not the 4th generation. Moreover, there was increased the mRNA expression for histone acetyltransferase and methyl transferases for H3K4 in the 1st and 2nd generation offspring compared to the control group. This study implicates that maternal high-fructose intake induces hypertension in multigenerational offspring through activating histone codes on the PRR promoter. Image 1 • Maternal high-fructose intake induces hypertension in F1 and F2 offspring. • Maternal high-fructose intake induces epigenetic activation of (pro)renin receptor in F1, F2 and F3 offspring. • Histones on the (pro)renin receptor promoter are acetylated. [ABSTRACT FROM AUTHOR]

Shear stress (SS) and renin-angiotensin system (RAS) play important roles in endothelium homeostasis. Previous studies demonstrated that pulsatile shear stress (PSS) reduced the expression and activity of angiotensin-converting enzyme (ACE), however, the effect of SS on angiotensin-converting enzyme 2 (ACE2) expression is unclear. We exposed cultured endothelial cells (ECs) to distinct patterns of SS for indicated time points, Western blot and RT-PCR were used to determine the ACE2 expression; En Face staining was used to detect ACE2 expression in vivo; cell proliferation and apoptosis were determined by BrdU staining and TUNEL staining, respectively; the production of NO was detected by a commercial kit; the promoter activity of ACE2 was determined by a Dual-Luciferase Reporter Assay System, inhibitors of ACE2 and signaling pathway were added to the medium 1 h prior for PSS. Our data showed PSS induced a sustained ACE2 expression, but OSS only induced a transient ACE2 expression. The PSS-induced ACE2 expression was higher than that of OSS both in vitro and in vivo. The PSS-induced ACE2 was involved in inhibiting proliferation and inflammation, as well as promoting NO production in ECs. PSS significantly increased ACE2 expression at transcriptional level via activating AMPKα2-KLF2 pathway. Our results suggest PSS promotes ACE2 expression via AMPKα2-KLF2 pathway to maintain the normal EC functions. In the, we firstly demonstrated that • Pulsatile shear stress (PSS) increased the ACE2 expression • PSS- induced ACE2 was participated in promoting the NO production, reducing the proliferation and inflammation of sheared ECs. • The AMPK-KLF2 pathway was involved in the upregulation of ACE2 by PSS.This work will help us further understand the relationship between RAS and mechanical forces. [ABSTRACT FROM AUTHOR]

Plasma aldosterone concentration increases in proportion to the severity of heart failure, even during treatment with renin-angiotensin system inhibitors. This study investigated alternative regulatory mechanisms of aldosterone production that are significant in heart failure. Dahl salt-sensitive rats on a high-salt diet, a rat model of heart failure with cardio-renal syndrome, had high plasma aldosterone levels and elevated β3-adrenergic receptor expression in hypoxic zona glomerulosa cells. In H295R cells (a human adrenocortical cell line), hypoxia-induced β3-adrenergic receptor expression. Hypoxia-mediated β3-adrenergic receptor expression augmented aldosterone production by facilitating hydrolysis of lipid droplets though ERK-mediated phosphorylation of hormone-sensitive lipase, also known as cholesteryl ester hydrolase. Hypoxia also accelerated the synthesis of cholesterol esters by acyl-CoA:cholesterol acyltransferase, thereby increasing the cholesterol ester content in lipid droplets. Thus, hypoxia enhanced aldosterone production by zona glomerulosa cells via promotion of the accumulation and hydrolysis of cholesterol ester in lipid droplets. In conclusion, hypoxic zona glomerulosa cells with heart failure show enhanced aldosterone production via increased catecholamine responsiveness and activation of cholesterol trafficking, irrespective of the renin-angiotensin system. • Plasma aldosterone increases in proportion to the severity of heart failure. • This even occurs during treatment with renin-angiotensin system inhibitors. • Alternative regulatory mechanisms of aldosterone production become significant. • Hypoxia enhances aldosterone production by the zona glomerulosa cells. • This occurs via catecholamine responsiveness acquisition and activation of cholesterol trafficking. [ABSTRACT FROM AUTHOR]

Hypertension is an independent risk factor for atrial fibrillation (AF), although its specific mechanisms remain unclear. Previous research has been focused on cyclic stretch, ignoring the role of high hydrostatic pressure. The present study aimed to explore the effect of high hydrostatic pressure stimulation on electrical remodeling in atrial myocytes and its potential signaling pathways. Experiments were performed on left atrial appendages from patients with chronic AF or sinus rhythm, spontaneously hypertensive rats (SHRs) treated with or without valsartan (10 mg/kg/day) and HL-1 cells were exposed to high hydrostatic pressure using a self-developed device. Whole-cell patch-clamp recordings and western blots demonstrated that the amplitudes of I Ca,L , I to , and I Kur were reduced in AF patients with corresponding changes in protein expression. Angiotensin protein levels increased and Ang1–7 decreased, while focal adhesion kinase (FAK) and Src kinase were enhanced in atrial tissue from AF patients and SHRs. After rapid atrial pacing, AF inducibility in SHR was significantly higher, accompanied by a decrease in I Ca,L , upregulation of I to and I Kur , and a shortened action potential duration. Angiotensin upregulation and FAK/Src activation in SHR were inhibited by angiotensin type 1 receptor inhibitor valsartan, thus, preventing electrical remodeling and reducing AF susceptibility. These results were verified in HL-1 cells treated with high hydrostatic pressure, and demonstrated that electrical remodeling regulated by the FAK-Src pathway could be modulated by valsartan. The present study indicated that high hydrostatic pressure stimulation increases AF susceptibility by activating the renin-angiotensin system and FAK-Src pathway in atrial myocytes. Unlabelled Image • To explore the direct effects of hydrostatic pressure on the pathogenesis of AF. • High-pressure increased AF susceptibility by altering I Ca, L , I to , I Kur and APD. • Ang II-AT1R was involved in high-pressure induced atrial electrical remodeling. • FAK-Src was the potential signaling pathway and regulated by Ang II-AT1R. [ABSTRACT FROM AUTHOR]

There is growing evidence that renin-angiotensin system (RAS) components have been involved in the development of various types of cancers, including prostate cancer. This article for the first time reports the impact of Ang1-9 and Ang3-7 on viability and proliferation, migration and invasion of epithelial prostate cells. The results of this study clearly show that Ang1-9 and Ang3-7 exert different/opposite effects on in vitro biological properties of prostate cells. It appears that Ang1-9 has pro - cancer activities via the ability to induce cell divisions, enhance cell motility and stimulate the expression of such genes as vascular endothelial growth factor (VEGF), hypoxia-inducible factors (HIF-1), vimentin (VIM) and REL proto-oncogene, NF-kB subunit (REL). On the contrary, Ang3-7 did not show any mitogenic activity. Furthermore, this peptide hormone limited the migration of PNT1A cells probably by downregulation of VEGF and VIM expression. Finally, it is worth noting that both angiotensins have the ability to modulate gene expression for angiotensin receptors. Unfortunately, we could not unequivocally identify the type of angiotensin receptor responsible for signal transduction pathway involved in PNT1A cell survival and proliferation. Undoubtedly, further research and testing in this area are necessary. Image 1 • Ang1-9 and Ang3-7 exert different effects on the viability, proliferation and the spread of prostate epithelial cells. • Ang1-9, appears to have pro-tumorigenic whereas Ang3-7 did not show any mitogenic activity. • Ang1-9 induces cell divisions and the cell motility as well as stimulation of the expression of genes: VEGFA, HIF-1α, VIM, REL. • Ang3-7 limits the migration of PNT1A cells probably by downregulating VEGFA and VIM expression. [ABSTRACT FROM AUTHOR]

Angiotensin processing peptidases (carboxypeptidase A (CPA) and chymase) are stored in cardiac mast cell (MC) secretory granules in large quantity and are co-released into the extracellular environment after activation/degranulation. In the human heart, chymase is primarily responsible for angiotensin II (Ang II) generation from the alternate substrate angiotensin-(1–12) (Ang-(1–12)). We investigated the individual and combined hydrolytic specificity of CPA and chymase enzymes (1:1 and 1:⅓ ratio) in the processing of the human Ang-(1–12) (hAng-(1–12)) substrate. To determine the K m and V max , the CPA and recombinant human chymase (rhChymase) enzymes were incubated with increasing concentrations of hAng-(1–12) substrate (0–300 μM). We found that CPA alone sequentially metabolized hAng-(1–12) substrate into angiotensin-(1–9) (Ang-(1–9), 53%), Ang II (22%) and angiotensin-(1–7) (Ang-(1–7), 11%) during a 15 min incubation. In the presence of rhChymase alone, 125I-hAng-(1–12) was directly metabolized into Ang II (89%) and no further hydrolysis of Ang II was detected. In the presence of both CPA + rhChymase enzymes (1:1 or 1:⅓ ratio), the amount of Ang II formation from 125I-hAng-(1–12) within a 5 min incubation period were 68% or 65%, respectively. In the presence of both (CPA + rhChymase), small amounts of Ang-(1–9) and Ang-(1–7) were generated from 125I-hAng-(1–12). The K m and V max values were 150 ± 5 μM and 384 ± 23 nM/min/mg of CPA and 40 ± 9 μM and 116 ± 20 nM/min/mg of rhChymase. The catalytic efficiency (V max /K m ratio) was higher for rhChymase/hAng-(1–12) compared to CPA/hAng-(1–12). Compared to CPA, chymase has a much higher affinity to hydrolyze the hAng-(1–12) substrate directly into Ang II. In addition, Ang II and Ang-(1–7) are the end products of chymase and CPA, respectively. Overall, our findings suggest that the Ang II generation from hAng-(1–12) is primarily mediated by chymase rather than CPA. • Mast cell peptidases (CPA and chymase) hydrolyze the human Ang-(1–12) substrate differently. • CPA alone hydrolyzed the human Ang-(1–12) substrate into Ang-(1–9), Ang II and Ang-(1–7). Chymase alone hydrolyzed the human Ang-(1–12) substrate directly into Ang II. • In the presence of both enzymes (CPA and chymase), Ang-(1–12) rapidly metabolized into Ang II. • Compared to CPA, chymase has higher affinity to hydrolyze the Ang-(1–12) substrate directly into Ang II. • Selective inhibition of chymase may provide greater benefit in the management of adverse cardiac remodeling. [ABSTRACT FROM AUTHOR]

Macrophages play an important role in inflammation and cardiac remodeling in response to myocardial infarction (MI). Earlier shift of inflammtory M1 macrophages to reparative M2 macrophages has demonstrated significant improvements in MI wound modeling and cardiac function. Here, we reported that TSLP could promote M1 to M2 macrophage polarization, and AngII skewed the macrophage phenotype towards M2 by inducing TSLP expression in vitro. Meanwhile, AngII could inhibit the expression of MMP2 and MMP9 in macrophages, which are engaged in ECM degradation and cardiac remodeling. In post-MI mice, TSLP expression were up-regulated in cardiac tissue and serum, probably induced by renin-angiotensin system activation and AngII level up-regulation following MI. Our study mapped the continuum of changes that occured in cardiac macrophages over the first week of MI, and found that rTSLP treatment promoted earlier phenotype shift of M1 to M2 macrophages, improving cardiac healing and ventricular function recovery. Taken together, this work identified a very promising therapeutic opportunity to manage macrophage phenotype and enhance resolution of inflammation in the post-MI heart. • TSLP could promote M1 to M2 macrophage polarization in vitro. • AngII skews the macrophage phenotype towards M2 by inducing TSLP expression. • AngII could inhibit the expression of MMP2/9 in macrophages, which are engaged in ECM degradation and cardiac remodeling. • rTSLP treatment promoted earlier phenotype shift of M1 to M2 macrophages, improving cardiac healing in vivo. [ABSTRACT FROM AUTHOR]

• AT2R-mediated feedbacks critically affect the mean-arterial pressure (MAP). • Stronger renin suppression significantly contributes in maintaining the normal MAP. • Tight AT2R-mediated regulation is relaxed in hyper-and hypotension. • AT2R control mechanism is robustly maintained with the MAP variations. The renin-angiotensin systems play pivotal role in cardiovascular physiology through its effects on regulating blood pressure and electrolyte homeostasis. Components of circulating RAS (cRAS) that include precursor angiotensinogen, two critical enzymes (renin and angiotensin-converting enzyme, ACE), their bioactive products, angiotensin- I, II together with its receptors (AT1R and AT2R) essentially determine this homeostasis. Most classical studies, however, showed the deleterious role of cRAS in elevating the blood pressure. Contemporary discovery of non-canonical components of the RAS has challenged this classic hypothesis that it can only exert deleterious effects on the cardiovascular systems. Using the classic cRAS model, we have designed in-silico experiments to test the hypothesis that AT2R-mediated feedback effects play pivotal role for maintaining the normal variation of the mean-arterial pressure (MAP).Beside the AT2R-mediation of downstream singling pathways consisting of several non-canonical RAS components, this study first time illustrated AT2R mediated feedback controls over the blood pressure regulation: one that impedes AT1R activity, and the other that downregulates renin. It has been shown that relatively stronger suppression of renin activity significantly contributes in maintaining the normal MAP and that tight AT2R-mediated regulation is relaxed in hyper-and hypotension. This control mechanism is noted to be robustly maintained with the MAP variations through an established linear steady-state relationship among renin, angiotensin I and angiotensin II. This examination suggests that AT2R-mediated downregulation of renin activities potentially counteracts the AT1R-mediated deleterious actions of Ang II. This study, therefore, provides a solid ground for considering different AT2 receptor adaptor protein and direct agonism at AT2R that can cause greater effects along with contemporary approaches of blocking AT1R mediation to attenuate hypertension or other cardiovascular disorders. [ABSTRACT FROM AUTHOR]

Overstimulation of the pro-inflammatory pathways within brain areas responsible for sympathetic outflow is well evidenced as a primary contributing factor to the establishment and maintenance of neurogenic hypertension. However, the precise mechanisms and stimuli responsible for promoting a pro-inflammatory state are not fully elucidated. Recent work has unveiled novel compounds derived from omega-3 polyunsaturated fatty acids (ω-3 PUFAs), termed specialized pro-resolving mediators (SPMs), which actively regulate the resolution of inflammation. Failure or dysregulation of the resolution process has been linked to a variety of chronic inflammatory and neurodegenerative diseases. Given the pathologic role of neuroinflammation in the hypertensive state, SPMs and their associated pathways may provide a link between hypertension and the long-standing association of dietary ω-3 PUFAs with cardioprotection. Herein, we review recent progress in understanding the RAS-driven pathophysiology of neurogenic hypertension, particularly in regards to the chronic low-grade neuroinflammatory response. In addition, we examine the potential for an impaired resolution of inflammation process in the context of hypertension. [ABSTRACT FROM AUTHOR]

Abstract The perivascular adipose tissue (PVAT) is located around the adventitia, composed primarily by adipocytes, stromal cells, leukocytes, fibroblasts and capillaries. It is well described that PVAT is an important modulator of the vascular tone being considered a biologically active tissue, releasing both vasoconstrictor and vasodilators factors. The literature shows that the anti-contractile effect induced by PVAT may be due to activation of the renin-angiotensin system (RAS). Aim Investigate whether the renin-angiotensin system participates in the effect exerted by perivascular adipose tissue on the vascular tone. Methods and results For this study we used thoracic aorta from Balb/c mice and performed vascular reactivity, nitric oxide and hydrogen peroxide quantification using selective probes and fluorescence microscopy, immunofluorescence to locate receptors and enzymes involved in this response. Our results demonstrated that perivascular adipose tissue induces an anti-contractile effect in endothelium-independent manner and involves Mas and AT 2 receptors participation with subsequent PI3K/Akt pathway activation. This pathway culminated with nitric oxide and hydrogen peroxide production by neuronal nitric oxide synthase, being hydrogen peroxide most relevant for the anti-contractile effect of perivascular adipose tissue. Conclusion For the first time in the literature, our results show the presence of Mas and AT 2 receptors, as well as, nitric oxide synthase on perivascular adipose tissue. Furthermore, our results show the involvement of Mas and AT 2 receptors and consequently nitric oxide synthase activation in the anti-contractile effect exerted by perivascular adipose tissue. Graphical abstract Image 1 Representative figure of the PVAT vasodilator pathway. Mas or AT 2 receptors activation in PVAT culminates in the PI3K – Akt pathway and NOS activation that induce the production NO and H 2 O 2 from eNOS and nNOS. Highlights • Presence of AT 2 and MAS receptors, as well as, nNOS and eNOS isoforms in the PVAT. • PVAT effect involves Mas, AT 2 and PI3k-Akt activation with NO and H 2 O 2 production. • RAS involvement in the PVAT vascular effect could be a potential pharmaceutical target. [ABSTRACT FROM AUTHOR]

Abstract Brain renin-angiotensin system (RAS) hyperactivity has been implicated in sympathetic hyperactivity and progressive left ventricular (LV) dysfunction after myocardial infarction (MI). Angiotensin III, generated by aminopeptidase A (APA), is one of the main effector peptides of the brain RAS in the control of cardiac function. We hypothesized that orally administered firibastat (previously named RB150), an APA inhibitor prodrug, would attenuate heart failure (HF) development after MI in mice, by blocking brain RAS hyperactivity. Two days after MI , adult male CD1 mice were randomized to three groups, for four to eight weeks of oral treatment with vehicle (MI + vehicle), firibastat (150 mg/kg; MI + firibastat) or the angiotensin I converting enzyme inhibitor enalapril (1 mg/kg; MI + enalapril) as a positive control. From one to four weeks post-MI, brain APA hyperactivity occurred, contributing to brain RAS hyperactivity. Firibastat treatment normalized brain APA hyperactivity, with a return to the control values measured in sham group two weeks after MI. Four and six weeks after MI, MI + firibastat mice had a significant lower LV end-diastolic pressure, LV end-systolic diameter and volume, and a higher LV ejection fraction than MI + vehicle mice. Moreover, the mRNA levels of biomarkers of HF (Myh7, Bnp and Anf) were significantly lower following firibastat treatment. For a similar infarct size, the peri-infarct area of MI + firibastat mice displayed lower levels of mRNA for Ctgf and collagen types I and III (markers of fibrosis) than MI + vehicle mice. Thus, chronic oral firibastat administration after MI in mice prevents cardiac dysfunction by normalizing brain APA hyperactivity, and attenuates cardiac hypertrophy and fibrosis. [ABSTRACT FROM AUTHOR]

Graphical abstract RAS inhibitors have been developed that target different aspects of RAS function including (1) membrane association; (2) exchange factor binding; (3) effector engagement; (4) dimerization. Abstract RAS has long been viewed as undruggable due to its lack of deep pockets for binding of small molecule inhibitors. However, recent successes in the development of direct RAS inhibitors suggest that the goal of pharmacological inhibition of RAS in patients may soon be realized. This review will discuss the role of RAS in cancer, the approaches used to develop direct RAS inhibitors, and highlight recent successes in the development of novel RAS inhibitory compounds that target different aspects of RAS biochemistry. In particular, this review will discuss the different properties of RAS that have been targeted by various inhibitors including membrane localization, the different activation states of RAS, effector binding, and nucleotide exchange. In addition, this review will highlight the recent success with mutation-specific inhibitors that exploit the unique biochemistry of the RAS(G12C) mutant. Although this mutation in KRAS accounts for 11% of all KRAS mutations in cancer, it is the most prominent KRAS mutant in lung cancer suggesting that G12C-specific inhibitors may provide a new approach for treating the subset of lung cancer patients harboring this mutant allele. Finally, this review will discuss the involvement of dimerization in RAS function and highlight new approaches to inhibit RAS by specifically interfering with RAS:RAS interaction. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Angiotensin-(19), a peptide of the non-classical renin angiotensin system, has been shown to prevent and revert hypertension and cardiac hypertrophy. We hypothetized that systemic delivery of angiotensin-(1–9) following myocardial infarction will also be protective and extend to provide protection during reperfusion of the ischemic heart. Adult Sprague Dawley rats were subjected to left anterior descending artery ligation and treated with angiotensin-(1–9) via osmotic mini-pump for 2 weeks in the presence or absence of Mas receptor or AT 2 R antagonists (A779 and PD123319, respectively). Myocardial death and left ventricular function were evaluated after infarction. Infarct size and functional parameters were determined in isolated rat hearts after global ischemia/reperfusion in the presence of angiotensin-(1–9) plus receptor antagonists or Akt inhibitor at reperfusion. in vitro , neonatal rat ventricular cardiomyocytes underwent simulated ischemia/reperfusion and angiotensin-(1–9) was co-incubated with A779, PD123319 or Akt inhibitor. Systemic delivery of angiotensin-(1–9) significantly decreased cell death and improved left ventricular recovery after in vivo myocardial infarction. Perfusion with the peptide reduced the infarct size and improved functional recovery after ex vivo ischemia/reperfusion. In vitro, angiotensin-(1–9) decreased cell death in isolated neonatal rat ventricular cardiomyocytes subjected to simulated ischemia/reperfusion. The cardioprotective effects of angiotensin-(1–9) were blocked by PD123319 and Akti VIII but not by A779. Angiotensin-(1–9) limits reperfusion-induced cell death by an AT 2 R- and Aktdependent mechanism. Angiotensin-(1–9) is a novel strategy to protect against cardiac ischemia/reperfusion injury. [ABSTRACT FROM AUTHOR]

Inhibition of the renin-angiotensin system in early postnatal life is a potential therapeutic approach to prevent long-term cardiovascular and kidney diseases in individuals born small. We determined the long-term effects of juvenile losartan treatment on cardiovascular and kidney function in control male rat offspring and those exposed to uteroplacental insufficiency and born small. Bilateral uterine vessel ligation (Restricted) or sham (Control) surgery was performed in late gestation in Wistar Kyoto rats. At weaning, male offspring were randomly assigned to receive losartan in their drinking water or drinking water alone from 5 to 8 weeks of age, and followed to 26 weeks of age. Systolic blood pressure and kidney function were assessed throughout the study. Pressure myography was used to assess passive mechanical wall properties in mesenteric and femoral arteries from 26-week-old offspring. Losartan treatment for three weeks lowered systolic blood pressure in both Control and Restricted groups but this difference was not sustained after the cessation of treatment. Losartan, irrespective of birth weight, mildly increased renal tubulointerstitial fibrosis when assessed at 26 weeks of age. Mesenteric artery stiffness was increased by the early losartan treatment, and was associated with increased collagen and decreased elastin content. Losartan also exerted long-term increases in fat mass and decreases in skeletal muscle mass. In this study, untreated Restricted offspring did not develop hypertension, vascular dysfunction or kidney changes as anticipated. Regardless, we demonstrate that short-term losartan treatment in the juvenile period negatively affects postnatal growth, and kidney and vascular parameters in adulthood, irrespective of birth weight. The long-term effects of early-life losartan treatment warrant further consideration in settings where the potential benefits may outweigh the risks; i.e. when programmed adulthood diseases are apparent and in childhood cardiovascular and kidney diseases. [ABSTRACT FROM AUTHOR]

Schistosomiasis mansoni is involved in hepatic fibrogenesis and portal hypertension. Previous studies proved that blockade of some components of the renin-angiotensin system (RAS) reduce liver fibrogenesis. However, the effects of inhibition of early stages of RAS pathway in schistosomal fibrosis have not been studied yet. Thus, the aim of this study was to compare the role of different antihypertensive drugs on hepatic fibrosis in murine schistosomiasis. BALB/c mice (n = 50) weighing 20g were subjected to inoculation of 50 cercariae and submitted to different treatments: aliskiren, 50 mg/kg (n = 10); bradykinin, 2 μg/kg (n = 5); losartan, 10 mg/kg (n = 10); lisinopril 10 mg/kg (n = 5) and control, proportional volume vehicle (n = 5); daily for 14 weeks. Six animals were not subjected to cercariae inoculation or any type of treatment. Ultrasound, histological, immunohistochemical and proteomic analyzes were performed to evaluate markers associated with hepatic fibrogenesis. The hepatic areas stained with Sirius red and thenumber of cells marked by α-SMA in animals treated with aliskiren, bradykinin, lisinopril and losartan were diminished when compared to control group, demonstrating reduced hepatic fibrosis after RAS blockade. These results were reinforced by ultrasonography analysis and protein expression of TGFβ. These findings demonstrated the effect of RAS inhibition on hepatic fibrosis in murine schistosomiasis, with the most evident results being observed in the losartan and aliskiren treated groups. The main mechanisms underlying this process appear to involve anti-fibrogenic activity through the inhibition of collagen and TGFβ synthesis. [ABSTRACT FROM AUTHOR]

The Ras small G-protein is a conserved regulator of cell and tissue growth during animal development. Studies in Drosophila have shown how Ras can stimulate a RAF-MEK-ERK signalling pathway to control cell growth and proliferation in response to Epidermal Growth Factor (EGF) stimulation. This work has also defined several transcription factors that can function as downstream growth effectors of the EGF/Ras/ERK pathway by stimulating mRNA transcription. Here we report on stimulation of RNA polymerase I (Pol I)-mediated ribosomal RNA (rRNA) synthesis as a growth effector of Ras/ERK signalling in Drosophila. We show that Ras/ERK signalling promotes an increase in nucleolar size in larval wing discs, which is indicative of increased ribosome synthesis. We also find that activation of Ras/ERK signalling promotes rRNA synthesis both in vivo and in cultured Drosophila S2 cells. We show that Ras signalling can regulate the expression of the Pol I transcription factor TIF-IA, and that this regulation requires dMyc. Finally, we find that TIF-IA-mediated rRNA synthesis is required for Ras/ERK signalling to drive proliferation in both larval and adult Drosophila tissues. These findings indicate that Ras signalling can promote ribosome synthesis in Drosophila , and that this is one mechanism that contributes to the growth effects of the Ras signalling pathway. [ABSTRACT FROM AUTHOR]

This review offers a contemporary history of the renin-angiotensin (RAS) and kallikrein-kinin (KKS) systems with emphasis on how these complex systems affect the eye. It describes the types of communication (cross-talk) between the two systems and evaluates their potential role in the development of diabetic retinopathy, diabetic macular edema, age-related macular degeneration, glaucoma, and uveitis. In addition to detailing the important physiological actions of components of the RAS and KKS, possibilities are suggested for new therapeutic avenues in the treatment of common ocular diseases. Historical notes indicate the major events in this research area, marking four decades from the first publication on the discovery of renin and angiotensin converting enzyme in the eye to the present time. [ABSTRACT FROM AUTHOR]

Abstract. Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor predisposition syndrome. Malignant peripheral nerve sheath tumors (MPNST) are aggressive soft tissue sarcomas arising from peripheral nerve sheaths, and the most commonly lethal feature associated with NF1. The hallmark of NF1 and NF1-related MPNST is the loss of neurofibromin expression. Loss of neurofibromin is considered a tumor-promoting event, and leads to constitutive activation of RAS and its downstream effectors. However, RAS activation alone is not sufficient for MPNST formation, and additional tumor suppressors and signaling pathways have been implicated in tumorigenesis of MPNST. Taking advantage of the rapid development of novel therapeutics targeting key molecular pathways across all cancer types, the best-in-class modulators of these pathways can be assessed in pre-clinical models and translated into clinical trials for patients with MPNST. Here, we describe the genetic changes and molecular pathways that drive MPNST formation and highlight the promise of signal transduction to identify therapies that may treat these tumors more effectively. [ABSTRACT FROM AUTHOR]

A growing literature has demonstrated that the renin-angiotensin system (RAS) involves in gut function. Angiotensin II (AngII) stimulates Cl − secretion in intestine epithelial cells. However, the underlying signal pathway remains unexplored. Here, we explored that serosal application of Ang II (5 × 10 −8 M) significantly increased the baseline I sc compared to the control group in rat ileum. Tetrodotoxin (TTX) failed to suppress I sc evoked by Ang II. However, the Ang II-evoked I sc was significantly suppressed by the ATR 1 antagonist losartan instead of ATR 2 antagonist PD123319. Of interest, both cyclooxygenase (COX)-1 inhibitor SC560 and COX-2 specific inhibitor ns398 blocked the Ang II-evoked I sc. Preincubation of submucosa/mucosa preparations with Ang II for 10 min significantly increased PGE2 production, which was abolished by either COX-1 or COX-2 inhibitor. In addition, the Ang II-induced PGE2 release was also attenuated by ATR 1 receptor antagonist rather than selective ATR 2 receptor antagonist. Furthermore, preincubation of tissues for 15 min with forskolin, a cAMP activator, markedly blocked the I sc evoked by AngII, while intracellular Ca 2+ pump inhibitor thapsigargin, L-type Ca 2+ channel blocker nicadipine or the epithelial Na + channel blocker amiloride didn't show such function. These results suggest that Ang II evokes cAMP-activated intestinal anion secretion by stimulating PGE2 release through activation of ATR1. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases (CVD) are among the main causes of death globally and in this context hypertension represents one of the key risk factors for developing a CVD. It is well established that the peripheral renin-angiotensin system (RAS) plays an important role in regulating blood pressure (BP). All components of the classic RAS can also be found in the brain but, in contrast to the peripheral RAS, how the endogenous RAS is involved in modulating cardiovascular effects in the brain is not fully understood yet. It is a complex system that may work differently in diverse areas of the brain and is linked to the peripheral system by the circumventricular organs (CVO), which do not have a blood brain barrier (BBB). In this review, we focus on the brain angiotensin peptides, their interactions with each other, and the consequences in the central nervous system (CNS) concerning cardiovascular control. Additionally, we present potential drug targets in the brain RAS for the treatment of hypertension. [ABSTRACT FROM AUTHOR]

The discovery of the (pro)renin receptor [(P)RR] 15 years ago stimulated ideas on prorenin being more than renin’s inactive precursor. Indeed, binding of prorenin to the (P)RR induces a conformational change in the prorenin molecule, allowing it to display angiotensin-generating activity, and additionally results in intracellular signaling in an angiotensin-independent manner. However, the prorenin levels required to observe these angiotensin-dependent and −independent effects of the (P)RR are many orders above its in vivo concentrations, both under normal and pathological conditions. Given this requirement, the idea that the (P)RR has a function within the renin-angiotensin system (RAS) is now being abandoned. Instead, research is now focused on the (P)RR as an accessory protein of vacuolar H + -ATPase (V-ATPase), potentially determining its integrity. Acting as an adaptor between Frizzled co-receptor LRP6 and V-ATPase, the (P)RR appears to be indispensable for Wnt/β-catenin signaling, thus explaining why (P)RR deletion (unlike renin deletion) is lethal even when restricted to specific cells, such as cardiomyocytes, podocytes and smooth muscle cells. Furthermore, recent studies suggest that the (P)RR may play important roles in lipoprotein metabolism and overall energy metabolism. In this review, we summarize the controversial RAS-related effects of the (P)RR, and critically review the novel non-RAS-related functions of the (P)RR, ending with a discussion on the potential of targeting the (P)RR to treat cardiovascular diseases. [ABSTRACT FROM AUTHOR]

The renin-angiotensin system (RAS) plays an important role in the initiation and progression of cardiovascular and renal diseases. These actions mediated by AT1 receptor (AT1R) are well established and led to development of selective AT1R blockers (ARBs). In contrast, there is scientific evidence that AT2 receptor (AT2R) mediates effects different from and often opposing those of the AT1R. Meagrely expressed in healthy tissue the AT2R is upregulated in injuries providing an endogenous protection to inflammatory, oxidative and apoptotic processes. Interestingly the beneficial effects mediated by AT2R can be further enhanced by pharmacological intervention using the recently developed AT2R agonists. This review article summarizes our current knowledge about regulation, signalling and effects mediated by AT2R in health and disease, with emphasis on cardiac and renal systems. At the end a novel concept of natural protective systems will be introduced and discussed as an attractive target in drug development. [ABSTRACT FROM AUTHOR]

A collective century of discoveries establishes the importance of the renin angiotensin aldosterone system in maintaining blood pressure, fluid volume and electrolyte homeostasis via autocrine, paracrine and endocrine signaling. While research continues to yield new functions of angiotensin II and angiotensin-(1–7), the gap between basic research and clinical application of these new findings is widening. As data accumulates on the efficacy of angiotensin converting enzyme inhibitors and angiotensin II receptor blockers as drugs of fundamental importance in the treatment of cardiovascular and renal disorders, it is becoming apparent that the achieved clinical benefits is suboptimal and surprisingly no different than what can be achieved with other therapeutic interventions. We discuss this issue and summarize new pathways and mechanisms effecting the synthesis and actions of angiotensin II. The presence of renin-independent non-canonical pathways for angiotensin II production are largely unaffected by agents inhibiting renin angiotensin system activity. Hence, new efforts should be directed to develop drugs that can effectively block the synthesis and/or action of intracellular angiotensin II. Improved drug penetration into cardiac or renal sites of disease, inhibiting chymase the primary angiotensin II forming enzyme in the human heart, and/or inhibiting angiotensinogen synthesis would all be more effective strategies to inhibit the system. Additionally, given the role of angiotensin II in the maintenance of renal homeostatic mechanisms, any new inhibitor should possess greater selectivity of targeting pathogenic angiotensin II signaling processes and thereby limit inappropriate inhibition. [ABSTRACT FROM AUTHOR]

A canonical brain Renin-Angiotensin System (RAS), like the canonical peripheral RAS, has long been proposed as a major regulator of brain function. Because of methodological limitations, however, this system is in urgent need of critical revision. The Angiotensin II AT1 receptors have been confirmed as key factors in the regulation of brain function, and AT1 receptor over activity has been established as a major and early injury factor in the development of many brain diseases. Consequently, Angiotensin Receptor Blockers (ARBs), compounds widely used to treat cardiovascular and metabolic disorders, are excellent candidates for repurposing for the treatment of brain disorders. This review will discuss some of the reasons why revisiting brain RAS is a pressing necessity, will present evidence for a participation of AT1 receptor over activity in the development of major brain disorders, and will present definite evidence of ARBs neuroprotective effects. The review will focus on the beneficial effects of ARB therapy in stroke, neurodegenerative disorders including Alzheimer’s and Parkinson’s diseases, traumatic brain injury, radiation- induced brain damage, stress and mood disorders. [ABSTRACT FROM AUTHOR]

The renin-angiotensin system (RAS) is undisputedly one of the most prominent endocrine (tissue-to-tissue), paracrine (cell-to-cell) and intracrine (intracellular/nuclear) vasoactive systems in the physiological regulation of neural, cardiovascular, blood pressure, and kidney function. The importance of the RAS in the development and pathogenesis of cardiovascular, hypertensive and kidney diseases has now been firmly established in clinical trials and practice using renin inhibitors, angiotensin-converting enzyme (ACE) inhibitors, type 1 (AT 1 ) angiotensin II (ANG II) receptor blockers (ARBs), or aldosterone receptor antagonists as major therapeutic drugs. The major mechanisms of actions for these RAS inhibitors or receptor blockers are mediated primarily by blocking the detrimental effects of the classic angiotensinogen/renin/ACE/ANG II/AT 1 /aldosterone axis. However, the RAS has expanded from this classic axis to include several other complex biochemical and physiological axes, which are derived from the metabolism of this classic axis. Currently, at least five axes of the RAS have been described, with each having its key substrate, enzyme, effector peptide, receptor, and/or downstream signaling pathways. These include the classic angiotensinogen/renin/ACE/ANG II/AT 1 receptor, the ANG II/APA/ANG III/AT 2 /NO/cGMP, the ANG I/ANG II/ACE2/ANG (1–7)/ Mas receptor, the prorenin/renin/prorenin receptor (PRR or Atp6ap2)/MAP kinases ERK1/2/V-ATPase, and the ANG III/APN/ANG IV/IRAP/AT 4 receptor axes. Since the roles and therapeutic implications of the classic angiotensinogen/renin/ACE/ANG II/AT 1 receptor axis have been extensively reviewed, this article will focus primarily on reviewing the roles and therapeutic implications of the vasoprotective axes of the RAS in cardiovascular, hypertensive and kidney diseases. [ABSTRACT FROM AUTHOR]

The renin-angiotensin system (RAS) is a major circulative system engaged in homeostasis modulation. Angiotensin II (Ang II) serves as its main effector hormone upon binding to its primary receptor, Ang II receptor type 1 (AT 1 R). It is well established that an intrinsic independent brain RAS exists. Abnormal AT 1 R activation both in the periphery and in the brain probably contributes to the development of Alzheimer’s disease (AD) pathology that is characterized, among others, by brain inflammation. Moreover, treatment with drugs that block AT 1 R (AT 1 R blockers, ARBs) ameliorates most of the clinical risk factors leading to AD. Previously we showed that short period of intranasal treatment with telmisartan (a brain penetrating ARB) reduced brain inflammation and ameliorated amyloid burden (a component of Alzheimer’s plaques) in AD transgenic mouse model. In the present study, we aimed to examine the long-term effect of intranasally administrated telmisartan on brain inflammation features including microglial activation, astrogliosis, neuronal loss and hippocampus-dependent cognition in five-familial AD mouse model (5XFAD). Five month of intranasal treatment with telmisartan significantly reduced amyloid burden in the cortex and hippocampus of 5XFAD mice as compared with the vehicle-treated 5XFAD group. Similar effects were also observed for CD11b staining, which is a marker for microglial accumulation. Telmisartan also significantly reduced astrogliosis and neuronal loss in the cortex of 5XFAD mice compared with the vehicle-treated group. Improved spatial acquisition of the 5XFAD mice following long-term intranasal administration of telmisartan was also observed. Taken together, our data suggest a significant role for AT1R blockage in mediating neuronal loss and cognitive behavior, possibly through regulation of amyloid burden and glial inflammation. [ABSTRACT FROM AUTHOR]

A deep interaction between the endometrium and the invading trophoblast occurs during implantation in humans, with the acquisition of uterine receptivity to the invading embryo promoted by an elevation of pro-inflammatory cytokines in the endometrium, and the invasiveness of decidualizing endometrial stromal cells, augmented by trophoblast-derived signals. Considering that usage of angiotensin II type 1 (AT1) receptor blockers, among other renin-angiotensin system (RAS) antagonists, is associated with adverse pregnancy outcomes, here we aim to analyse the involvement of AT1 receptor in the reciprocal dialogue occurring between endometrial stroma and trophoblast cells. In human endometrial stromal cells (T-HESC) pre-incubated with a decidualization cocktail, angiotensin (Ang) II increased protein expression of prolactin and FOXO1, markers of endometrial decidualization, while promoting nuclear translocation of FOXO1. In addition, Ang II treatment increased CXCL8, and matrix metalloprotease (MMP)-2 levels in T-HESC. Incubation with the AT1 receptor blocker losartan or with an NFAT signalling inhibitor, decreased Ang II-induced secretion of prolactin, CXCL8, and MMP-2 in T-HESC. In a wound healing assay, conditioned medium (CM) obtained from Ang II-treated T-HESC, but not CM from losartan-pre-incubated T-HESC, increased migration of HTR-8/SVneo trophoblasts, effect that was inhibited in the presence of a CXCL8-neutralizing antibody. An increased secretion of CXCL8 and MMP-2 was observed after treatment of T-HESC with CM obtained from HTR-8/SVneo cells, which was not observed in T-HESC pre-incubated with losartan or with the NFAT inhibitor. This study evidenced a reciprocal RAS-coded messaging between trophoblast and ESC which is affected by the AT1 receptor blocker losartan. • Ang II increased Prolactin and FOXO1 in decidualized endometrial stromal cells (ESC). • CXCL8 chemokine from Ang II-stimulated ESC, enhanced trophoblast migration. • AT1R/NFAT inhibition in ESC decreased decidualization and trophoblast migration. • Hormone-conditioned trophoblasts induced inflammatory events in ESC via AT1R/NFAT. • ESC/trophoblast crosstalk may be regulated by RAS-coded signals. [ABSTRACT FROM AUTHOR]

Cardiorenal syndrome encompasses a spectrum of disorders involving heart and kidney dysfunction, and sharing common risk factors, such as hypertension and diabetes. Clinical studies have shown that patients with and without diabetes may benefit from using sodium-glucose cotransporter 2 inhibitors to reduce the risk of heart failure and ameliorate renal endpoints. Because the underlying mechanisms remain elusive, we investigated the effects of dapagliflozin on the progression of renal damage, using a model of non-diabetic cardiorenal disease. Dahl salt-sensitive rats were fed a high-salt diet for five weeks and then randomized to dapagliflozin or vehicle for the following six weeks. After treatment with dapagliflozin, renal function resulted ameliorated as shown by decrease of albuminuria and urine albumin-to-creatinine ratio. Functional benefit was accompanied by a decreased accumulation of extracellular matrix and a reduced number of sclerotic glomeruli. Dapagliflozin significantly reduced expression of inflammatory and endothelial activation markers such as NF-κB and e-selectin. Upregulation of pro-oxidant-releasing NADPH oxidases 2 and 4 as well as downregulation of antioxidant enzymes were also counteracted by drug treatment. Our findings also evidenced the modulation of both classic and non-classic renin-angiotensin-aldosterone system (RAAS), and effects of dapagliflozin on gene expression of ion channels/transporters involved in renal homeostasis. Thus, in a non-diabetic model of cardiorenal syndrome, dapagliflozin provides renal protection by modulating inflammatory response, endothelial activation, fibrosis, oxidative stress, local RAAS and ion channels. [Display omitted] [ABSTRACT FROM AUTHOR]

Introduction Chronic Obstructive Pulmonary Disease (COPD) is the fifth cause of mortality worldwide. Systemic inflammation is a crucial element in its physiopathology. As Renin-Angiotensin System is one of the main components of this inflammatory neurohumoral cascade, Angiotensin Receptor Blockers (ARBs) might have an effect on mortality in COPD patients. Goal To evaluate the association between ARBs treatment and mortality in COPD patients. Methods Retrospective cohort of patients with diagnosis of COPD from 2003 to 2013. COPD cases were detected according to the diagnosis by treating physicians in any field of the electronic clinical health records by controlled vocabulary in patients older than 18 years affiliated to the Hospital Italiano de Buenos Aires (HIBA) Health Plan. Patients were classified in two groups depending on their use of ARBs according to the hospital pharmacy records. The mortality registry of the HIBA was used to obtain the event of death. The 8 year survival experience was described using Kaplan Meier estimator and survival curve comparisons were calculated with the Cox Mantel test. Hazard Ratios (HR) were estimated using a Cox proportional risk model. A propensity score (PS) was developed for the use of ARBs. Results 1140 deaths were detected, 1063 in the no exposure group and 77 in the ARBs exposure group. The 8 year survival was 71% (CI 95% 69–72%). The survival in the non exposed group was 71% (CI 95% 69–73%) and 76% (CI 95% 0,69-0,81) in the ARBs exposed group. The unadjusted HR for mortality was 0.85 (CI 95% 0.67–1.07, p = 0.17) and the adjusted HR by PS was 0.63 (CI 95% 0.50–0.80, p < 0.001). Discussion ARBs use seems to be associated to a lower mortality in patients with COPD. Additional studies are needed to corroborate this finding. [ABSTRACT FROM AUTHOR]

The potential protective effect of renin-angiotensin system (RAS) inhibitors is a subject of increasing interest due to their possible role as chemopreventive agents against colorectal cancer (CRC). To evaluate this association, we conducted a case-control study with 2165 cases of colorectal cancer, diagnosed between 2007 and 2012, and 3912 population controls frequency matched (by age, sex and region) from the Spanish multicenter case-control study MCC-Spain. We found a significant protective effect of the angiotensin-converting enzyme Inhibitors (ACEIs) against CRC, limited to the under-65years group (OR=0.65 95%CI (0.48-0.89)) and to a lesser degree to men (OR=0.81 95%CI (0.66-0.99). In contrast, the angiotensin receptor blockers (ARBs) did not show a significant effect. Regarding the duration of use, a greater protection was observed in men as the length of consumption increases. In contrast, in the under-65 stratum, the strongest association was found in short-term treatments. Finally, by analyzing ACEIs effect by colon subsite, we found no differences, except for under 65years old, where the maximum protection was seen in the proximal intestine, descending in the distal and rectum (without statistical significance). In conclusion, our study shows a protective effect on CRC of the ACEis limited to males and people under 65years old, which increases in proximal colon in the latter. If confirmed, these results may suggest a novel approach to proximal CRC prevention, given the shortcomings of colonoscopy screening in this location. [ABSTRACT FROM AUTHOR]

Vitamin D receptor (VDR) deficient status has been shown to be associated with the activation of renin angiotensin system (RAS). We hypothesized that lack of VDR would enhance p53 expression in podocytes through down regulation of SIRT1; the former would enhance the transcription of angiotensinogen (Agt) and angiotensinogen II type 1 receptor (AT1R) leading to the activation of RAS. Renal tissues of VDR mutant (M) mice displayed increased expression of p53, Agt, renin, and AT1R. In vitro studies, VDR knockout podocytes not only displayed up regulation p53 but also displayed enhanced expression of Agt, renin and AT1R. VDR deficient podocytes also displayed an increase in mRNA expression for p53, Agt, renin, and AT1R. Interestingly, renal tissues of VDR-M as well as VDR heterozygous (h) mice displayed attenuated expression of deacetylase SIRT1. Renal tissues of VDR-M mice showed acetylation of p53 at lysine (K) 382 residues inferring that enhanced p53 expression in renal tissues could be the result of ongoing acetylation, a consequence of SIRT1 deficient state. Notably, podocytes lacking SIRT1 not only showed acetylation of p53 at lysine (K) 382 residues but also displayed enhanced p53 expression. Either silencing of SIRT1/VDR or treatment with high glucose enhanced podocyte PPAR-y expression, whereas, immunoprecipitation (IP) of their lysates with anti-retinoid X receptor (RXR) antibody revealed presence of PPAR-y. It appears that either the deficit of SIRT1 has de-repressed expression of PPAR-y or enhanced podocyte expression of PPAR-y (in the absence of VDR) has contributed to the down regulation of SIRT1. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a complex illness characterized by progressive dopaminergic neuronal loss. Several mechanisms associated with the iron-induced death of dopaminergic cells have been described. Ferroptosis is an iron-dependent, regulated cell death process that was recently described in cancer. Our present work show that ferroptosis is an important cell death pathway for dopaminergic neurons. Ferroptosis was characterized in Lund human mesencephalic cells and then confirmed ex vivo (in organotypic slice cultures) and in vivo (in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model). Some of the observed characteristics of ferroptosis differed from those reported previously. For example, ferroptosis may be initiated by PKCα activation, which then activates MEK in a RAS-independent manner. The present study is the first to emphasize the importance of ferroptosis dysregulation in PD. In neurodegenerative diseases like PD, iron chelators, Fer-1 derivatives and PKC inhibitors may be strong drug candidates to pharmacologically modulate the ferroptotic signaling cascade. [ABSTRACT FROM AUTHOR]

The neuroprotective effects of menopausal hormonal therapy in Parkinson’s disease (PD) have not yet been clarified, and it is controversial whether there is a critical period for neuroprotection. Studies in animal models and clinical and epidemiological studies indicate that estrogens induce dopaminergic neuroprotection. Recent studies suggest that inhibition of the brain renin-angiotensin system (RAS) mediates the effects of estrogens in PD models. In the substantia nigra, ovariectomy induces a decrease in levels of estrogen receptor-α (ER-α) and increases angiotensin activity, NADPH-oxidase activity and expression of neuroinflammatory markers, which are regulated by estrogen replacement therapy. There is a critical period for the neuroprotective effect of estrogen replacement therapy, and local ER-α and RAS play a major role. Astrocytes play a major role in ER-α-induced regulation of local RAS, but neurons and microglia are also involved. Interestingly, treatment with angiotensin receptor antagonists after the critical period induced neuroprotection. [ABSTRACT FROM AUTHOR]

We showed previously that rat angiotensin-(1-12) [Ang-(1-12)] is metabolized by chymase and angiotensin converting enzyme (ACE) to generate Angiotensin II (Ang II). Here, we investigated the affinity of cardiac chymase and ACE enzymes for Ang-(1-12) and Angiotensin I (Ang I) substrates. Native plasma membranes (PMs) isolated from heart and lung tissues of adult spontaneously hypertensive rats (SHR) were incubated with radiolabeled 125 I-Ang-(1-12) or 125 I-Ang I, in the absence or presence of a chymase or ACE inhibitor (chymostatin and lisinopril, respectively). Products were quantitated by HPLC connected to an in-line flow-through gamma detector. The rate of 125 I-Ang II formation from 125 I-Ang-(1-12) by chymase was significantly higher (heart: 7.0 ± 0.6 fmol/min/mg; lung: 33 ± 1.2 fmol/min/mg, P < 0.001) when compared to 125 I-Ang I substrate (heart: 0.8 ± 0.1 fmol/min/mg; lung: 2.1 ± 0.1 fmol/min/mg). Substrate affinity of 125 I-Ang-(1-12) for rat cardiac chymase was also confirmed using excess unlabeled Ang-(1-12) or Ang I (0–250 μM). The rate of 125 I-Ang II formation was significantly lower using unlabeled Ang-(1-12) compared to unlabeled Ang I substrate. Kinetic data showed that rat chymase has a lower K m (64 ± 6.3 μM vs 142 ± 17 μM), higher V max (13.2 ± 1.3 μM/min/mg vs 1.9 ± 0.2 μM/min/mg) and more than 15-fold higher catalytic efficiency (ratio of V max /K m ) for Ang-(1-12) compared to Ang I substrate, respectively. We also investigated ACE mediated hydrolysis of 125 I-Ang-(1-12) and 125 I-Ang I in solubilized membrane fractions of the SHR heart and lung. Interestingly, no significant difference in 125 I-Ang II formation by ACE was detected using either substrate, 125 I-Ang-(1-12) or 125 I-Ang I, both in the heart (1.8 ± 0.2 fmol/min/mg and 1.8 ± 0.3 fmol/min/mg, respectively) and in the lungs (239 ± 25 fmol/min/mg and 248 ± 34 fmol/min/mg, respectively). Compared to chymase, ACE-mediated Ang-(1-12) metabolism in the heart was several fold lower. Overall our findings suggest that Ang-(1-12), not Ang I, is the better substrate for Ang II formation by chymase in adult rats. In addition, this confirms our previous observation that chymase (rather than ACE) is the main hydrolyzing enzyme responsible for Ang II generation from Ang-(1-12) in the adult rat heart. [ABSTRACT FROM AUTHOR]

Members of the Ras-like GTPase superfamily are key regulators of diverse cellular and developmental events, including differentiation, cell division, vesicle transport, nuclear assembly, and cytoskeleton control. In this study, three Ras family members ( MjRap , MjRas , and MjRal ) were cloned from Marsupenaeus japonicu s. The full lengths of MjRap , MjRas , and MjRal are 788, 1330, and 2074 bp, which encode the proteins of 186, 202, and 198 amino acids respectively. Phylogenetic analysis showed that Rap, Ras, and Ral from different species gather together. The MjRap , MjRas , and MjRal genes were ubiquitously expressed in the hemocytes, hepatopancreas, gills, stomach, and muscle. Results from the quantitative real-time polymerase chain reaction (qRT-PCR) showed that MjRal in the gills was upregulated 48 and 72 h post-White spot syndrome virus (WSSV) challenge. No change in the MjRap or MjRas transcript was observed in the gills under the WSSV challenge. The RNAi of MjRal could enhance the WSSV replication. Injection of rMjRal protein could inhibit WSSV replication, but had no effect on VP28 expression. So, it could be concluded that MjRal was involved in shrimp anti-viral innate immune defense by inhibiting the WSSV replication. [ABSTRACT FROM AUTHOR]

Organophosphates (OPs) are ubiquitous environmental contaminants, widely used as pesticides in agricultural fields. In addition, they serve as flame-retardants, plasticizers, antifoaming or antiwear agents in lacquers, hydraulic fluids, and floor polishing agents. Therefore, world-wide and massive application of these compounds have increased the risk of unintentional exposure to non-targets including the human beings. OPs are neurotoxic agents as they inhibit the activity of acetylcholinesterase at synaptic cleft. Moreover, they can fuel cardiovascular issues in the form of myocardities, cardiac oedema, arrhythmia, systolic malfunction, infarction, and altered electrophysiology. Such pathological outcomes might increase the severity of cardiovascular diseases which are the leading cause of mortality in the developing world. Coronavirus disease-19 (COVID-19) is the ongoing global health emergency caused by SARS-CoV-2 infection. Similar to OPs, SARS-CoV-2 disrupts cytokine homeostasis, redox-balance, and angiotensin-II/AT 1 R axis to promote cardiovascular injuries. Therefore, during the current pandemic milieu, unintentional exposure to OPs through several environmental sources could escalate cardiac maladies in patients with COVID-19. [Display omitted] • Organophosphates (OP) are ubiquitous chemicals having cardiotoxic potentials. • SARS-CoV-2 fuels cardiovascular issues in patients. • Both can disrupt redox, RAS, and cytokine homeostasis to fuel cardiovascular maladies. • Co-exposure can augment the risk of cardiovascular issues. [ABSTRACT FROM AUTHOR]

[Display omitted] • The search for domain-specific ACE inhibitors has been the focus of this report. • Ac-Ang (2–7)-NH 2 is a potential analogue to develop effective cACE inhibitors. • First dynamics simulation report of an Ang (1–7) derivative with both ACE domains. • Molecular dynamics simulations show Val3 and Tyr4 interactions with ACE subsites. • Our results can facilitate the development of domain-selective ACE inhibitors. The renin-angiotensin system (RAS) is a key regulator of human arterial pressure. Several of its effects are modulated by angiotensin II, an octapeptide originating from the action of angiotensin-I converting enzyme (ACE) on the decapeptide angiotensin-I. ACE possess two active sites (nACE and cACE) that have their own kinetic and substrate specificities. ACE inhibitors are widely used as the first-line treatment for hypertension and other heart-related diseases, but because they inactivate both ACE domains, their use is associated with serious side effects. Thus, the search for domain-specific ACE inhibitors has been the focus of intense research. Angiotensin (1–7), a peptide that also belongs to the RAS, acts as a substrate of nACE and an inhibitor of cACE. We have synthetized 15 derivatives of Ang (1–7), sequentially removing the N -terminal amino acids and modifying peptides extremities, to find molecules with improved selectivity and inhibition properties. Ac-Ang (2–7)-NH 2 is a good ACE inhibitor, resistant to cleavage and with improved cACE selectivity. Molecular dynamics simulations provided a model for this peptide's selectivity, due to Val3 and Tyr4 interactions with ACE subsites. Val3 has an important interaction with the S 3 subsite, since its removal greatly reduced peptide-enzyme interactions. Taken together, our findings support ongoing studies using insights from the binding of Ac-Ang (2–7)-NH 2 to develop effective cACE inhibitors. [ABSTRACT FROM AUTHOR]

Coronavirus disease-2019 (COVID-19) is a complex infection caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that can cause also gastrointestinal symptoms. There are various factors that determine the host susceptibility and severity of infection , including the renin-angiotensin system, the immune response, and the gut microbiota. In this regard, we aimed to investigate the gene expression of ACE, AGTR1 , ACE2, and TMPRSS2, which mediate SARS-CoV-2 pathogenesis by Akkermansia muciniphila , Faecalibacterium prausnitzii , Bacteroides thetaiotaomicron , and Bacteroides fragili s on Caco-2 cells. Also, the enrichment analysis considering the studied genes was analyzed on raw data from the microarray analysis of COVID-19 patients. Caco-2 cells were treated with live, heat-inactivated form and cell free supernatants of A. muciniphila , F. prausnitzii , B. thetaiotaomicron and B. fragilis for overnight. After RNA extraction and cDNA synthesis, the expression of studied genes was assessed by RT-qPCR. DNA methylation of studied genes was analyzed by Partek® Genomics Suite® software on the GSE174818 dataset. We used GSE164805 and GSE166552 datasets from COVID-19 patients to perform enrichment analysis by considering the mentioned genes via GEO2R, DAVID. Finally, the related microRNAs to GO terms concerned on the studied genes were identified by miRPath. The downregulation of ACE , AGTR1 , and ACE2 genes by A. muciniphila , F. prausnitzii , B. thetaiotaomicron , and B. fragilis in live, heat-inactivated, and cell-free supernatants was reported for the first time. These genes had hypomethylated DNA status in COVID-19 patients' raw data. The highest fold enrichment in upregulated RAS pathways and immune responses belonged to ACE, AGTR1, and ACE2 by considering the protein-protein interaction network. The common miRNAs targeting the studied genes were reported as miR-124-3p and miR-26b-5p. In combination with our experimental data and bioinformatic analysis, we showed the potential of A. muciniphila , F. prausnitzii, B. thetaiotaomicron , and B. fragilis and their postbiotics to reduce ACE, ATR1, and ACE2 expression, which are essential genes that drive upregulated biological processes in COVID-19 patients. Accordingly, due to the potential of studied bacteria on the alteration of ACE, AGTR1, ACE2 genes expression, understanding their correlation with demonstrated miRNAs expression could be valuable. These findings suggest the importance of considering targeted gut microbiota intervention when designing the possible therapeutic strategy for controlling the COVID-19. • Akkermansia muciniphila , Faecalibacterium prausnitzii , Bacteroides thetaiotaomicron , and Bacteroides fragilis , important gut microbiota members, downregulated expression of ACE , AGTR1 , and ACE2 genes mediating SARS-CoV-2 pathogenesis on Caco-2 cell line. • Postbiotic forms including, heat-inactivated and cell-free supernatants derived from A. muciniphila , F. prausnitzii, B. thetaiotaomicron, B. fragilis reduced genes expression of ACE , AGTR1 , and ACE2 favored to reducing of COVID-19 infection in human intestinal epithelial cells, Caco-2 cells. • Hypomethylated status of ACE , AGTR1 , and ACE2 were demonstrated by DNA methylation analysis on GSE174818 in COVID-19 patients and healthy control. • ACE , AGTR1 , and ACE2 had highest fold enrichment in upregulated process especially, renin angiotensin system activity and immune response, in COVID-19 patients compared with healthy control based on the enrichment analysis of differentially expressed genes (DEGs) derived two microarray datasets, GSE164805 and GSE166552. • The most important microRNAs which target ACE , AGTR1 , and ACE2 genes to control expression were identified, miR-124-3p and miR-26b-5p related to GO terms from enrichment analysis. [ABSTRACT FROM AUTHOR]