RESUMEN
The renin-angiotensin system (RAS) plays a vital role in cardiovascular physiology and body homeostasis. In addition to circulating RAS, a local RAS exists in the retina. Dysfunction of local RAS, resulting in increased levels of Angiotensin II (Ang II) and activation of AT1R-mediated signaling pathways, contributes to tissue pathophysiology and end-organ damage. Activation of AT2R on other hand is known to counteract the effects of AT1R activation and produce anti-inflammatory and anti-oxidative effects. We examined the expression of angiotensin receptors in the retina by using transgenic dual reporter mice and by real-time RT-PCR. We further evaluated the effects of C21, a selective agonist of AT2R, in reducing Ang II, lipopolysaccharide (LPS) and hydrogen peroxide induced oxidative stress and inflammatory responses in cultured human ARPE-19â¯cells. We showed that both AT1Ra and AT2R positive cells are detected in different cell types of the eye, including the RPE/choroid complex, ciliary body/iris, and neural retina. AT1Ra is more abundantly expressed than AT2R in mouse retina, consistent with previous reports. In the neural retina, AT1Ra are also detected in photoreceptors whereas AT2R are mostly expressed in the inner retinal neurons and RGCs. In cultured human RPE cells, activation of AT2R with C21 significantly blocked Ang II, LPS and hydrogen peroxide -induced NF-κB activation and inflammatory cytokine expression; Ang II and hydrogen peroxide-induced reactive oxygen species (ROS) production and MG132-induced apoptosis, comparable to the effects of Angiotensin-(1-7) (Ang-(1-7)), another protective component of the RAS, although C21 is more potent in reducing some of the effects induced by Ang II, whereas Ang-(1-7) is more effective in reducing some of the LPS and hydrogen peroxide-induced effects. These results suggest that activation of AT2R may represent a new therapeutic approach for retinal diseases.
Asunto(s)
Receptor de Angiotensina Tipo 2/metabolismo , Receptores de Angiotensina/agonistas , Epitelio Pigmentado de la Retina/efectos de los fármacos , Sulfonamidas/farmacología , Tiofenos/farmacología , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Supervivencia Celular , Células Cultivadas , Citocinas/metabolismo , Regulación de la Expresión Génica/fisiología , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , FN-kappa B/metabolismo , ARN Mensajero/genética , Especies Reactivas de Oxígeno/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptor de Angiotensina Tipo 2/genética , Sistema Renina-Angiotensina/fisiología , Retina/efectos de los fármacos , Retina/metabolismo , Retina/patología , Epitelio Pigmentado de la Retina/metabolismo , Epitelio Pigmentado de la Retina/patologíaRESUMEN
RATIONALE: We propose renin angiotensin system (RAS) peptides are critical in wound reparative processes such as in acute respiratory distress syndrome (ARDS). Their role in predicting clinical outcomes in ARDS has been unexplored; thus, we used a targeted metabolomics approach to investigate them as potential predictors of outcomes. METHODS: Thirty-nine ARDS patients were enrolled within 24 hours of ARDS diagnosis. Plasma RAS peptide levels were quantified at study entry and 24, 48 and 72 hours using a liquid chromatography-mass spectrometry based metabolomics assay. RAS peptide concentrations were compared between survivors and non-survivors, and were correlated with clinical and pulmonary measures. MEASUREMENTS AND MAIN RESULTS: Angiotensin I (Ang-I or A(1-10)) levels were significantly higher in non-survivors at study entry and 72 hours. ARDS survival was associated with lower A(1-10) concentration (OR 0.36, 95% CI 0.18-0.72, p = 0.004) but higher A(1-9) concentration (OR 2.24, 95% CI 1.15-4.39, p = 0.018), a biologically active metabolite of A(1-10) and an agonist of angiotensin II receptor type 2. Survivors had significantly higher median A(1-9)/A(1-10) and A(1-7)/A(1-10) ratios than the non-survivors (p = 0.001). Increased A(1-9)/A(1-10) ratio suggests that angiotensin converting enzyme II (ACE2) activity is higher in patients who survived their ARDS insult while an increase in A(1-7)/A(1-10) ratio suggests that ACE activity is also higher in survivors. CONCLUSION: A(1-10) accumulation and reduced A(1-9) concentration in the non-survivor group suggest that ACE2 activities may be reduced in patients succumbing to ARDS. Plasma levels of both A(1-10) and A(1-9) and their ratio may serve as useful biomarkers for prognosis in ARDS patients.
Asunto(s)
Angiotensina I/química , Péptidos/sangre , Síndrome de Dificultad Respiratoria/patología , Enfermedad Aguda , Adulto , Enzima Convertidora de Angiotensina 2 , Cromatografía Líquida de Alta Presión , Femenino , Humanos , Masculino , Persona de Mediana Edad , Peptidil-Dipeptidasa A/metabolismo , Proyectos Piloto , Receptores de Angiotensina/agonistas , Síndrome de Dificultad Respiratoria/mortalidad , Espectrometría de Masas en TándemRESUMEN
In vitro culture of ovarian follicles is a promising bioengineering technique for retrieving fertilizable oocytes from preserved ovarian tissues of cancer survivors. However, current in vitro follicle culture techniques are labour-intensive and of low efficiency, as only single follicle culture (SFC) has been possible to date. The present study investigated the feasibility of multifollicular cluster culture (MFCC) system using angiotensin II receptor (ATII-Rc) analogues. Ovarian pre-antral follicles isolated from 2-week-old C57BL6 mice were cultured with ATII-Rc agonist or antagonist and their maturation outcomes were compared with control group. When single follicles were cultured, the ovulation and maturation rates were similar in all three groups. When three-follicle clusters were cultured, up to three follicles were ovulated in the ATII-Rc agonist group while none or one follicle ovulated in control or antagonist groups (p < 0.0001). Significantly higher numbers of mature oocytes were obtained in the agonist group (three-follicle 28.2 ± 4.9 vs. SFC 11.0 ± 1.3, per 25 cultured droplets) (p < 0.0001), and the development of each fertilized oocytes was comparable to those from SFC. It is therefore concluded that this novel MFCC system can significantly improve the efficiency of in vitro mature oocyte retrieval via ATII-Rc modulation. Copyright © 2016 John Wiley & Sons, Ltd.
Asunto(s)
Antagonistas de Receptores de Angiotensina/farmacología , Folículo Ovárico/metabolismo , Ovulación/efectos de los fármacos , Receptores de Angiotensina/agonistas , Animales , Femenino , Ratones , Técnicas de Cultivo de Órganos , Folículo Ovárico/citologíaRESUMEN
Functional selectivity provides a new avenue to selectively engage particular pathways of the pleiotropic signaling repertoire of a G protein-coupled receptor. First examples for signaling biased compounds at the angiotensin II receptor and the µ opioid receptor have progressed to clinical trials and are promising in regard to selective activation of signaling pathways that can be linked to beneficial clinical outcomes. Dualsteric/bitopic hybrid compounds which consist of at least two pharmacophores combined in one single ligand are more recent examples for functionally selective ligands. Their binding topography makes them ideally suited to disrupt receptor flexibility and rationally induce signaling bias. Therefore, the dualsteric/bitopic design principle is most promising to facilitate generation of structurally diverse biased agonists at G protein-coupled receptors.
Asunto(s)
Diseño de Fármacos , Receptores Acoplados a Proteínas G/agonistas , Transducción de Señal/efectos de los fármacos , Animales , Humanos , Ligandos , Terapia Molecular Dirigida , Unión Proteica , Receptores de Angiotensina/agonistas , Receptores de Angiotensina/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Receptores Opioides mu/agonistas , Receptores Opioides mu/metabolismoRESUMEN
KEY POINTS: The renin-angiotensin system plays a key role in cardiovascular physiology and its overactivation has been implicated in the pathogenesis of several major cardiovascular diseases. There is growing evidence that angiotensin II (Ang-II) may function as an intracellular peptide to activate intracellular/nuclear receptors and their downstream signalling effectors independently of cell surface receptors. Current methods used to study intracrine Ang-II signalling are limited to indirect approaches because of a lack of selective intracellularly-acting probes. Here, we present novel photoreleasable Ang-II analogues used to probe intracellular actions with spatial and temporal precision. The photorelease of intracellular Ang-II causes nuclear and cytosolic calcium mobilization and initiates the de novo synthesis of RNA in cardiac cells, demonstrating the application of the method. ABSTRACT: Several lines of evidence suggest that intracellular angiotensin II (Ang-II) contributes to the regulation of cardiac contractility, renal salt reabsorption, vascular tone and metabolism; however, work on intracrine Ang-II signalling has been limited to indirect approaches because of a lack of selective intracellularly-acting probes. Here, we aimed to synthesize and characterize cell-permeant Ang-II analogues that are inactive without uncaging, but release active Ang-II upon exposure to a flash of UV-light, and act as novel tools for use in the study of intracrine Ang-II physiology. We prepared three novel caged Ang-II analogues, [Tyr(DMNB)(4)]Ang-II, Ang-II-ODMNB and [Tyr(DMNB)(4)]Ang-II-ODMNB, based upon the incorporation of the photolabile moiety 4,5-dimethoxy-2-nitrobenzyl (DMNB). Compared to Ang-II, the caged Ang-II analogues showed 2-3 orders of magnitude reduced affinity toward both angiotensin type-1 (AT1R) and type-2 (AT2R) receptors in competition binding assays, and greatly-reduced potency in contraction assays of rat thoracic aorta. After receiving UV-irradiation, all three caged Ang-II analogues released Ang-II and potently induced the contraction of rat thoracic aorta. [Tyr(DMNB)(4)]Ang-II showed the most rapid photolysis upon UV-irradiation and was the focus of subsequent characterization. Whereas Ang-II and photolysed [Tyr(DMNB)(4)]Ang-II increased ERK1/2 phosphorylation (via AT1R) and cGMP production (AT2R), caged [Tyr(DMNB)(4)]Ang-II did not. Cellular uptake of [Tyr(DMNB)(4)]Ang-II was 4-fold greater than that of Ang-II and significantly greater than uptake driven by the positive-control HIV TAT(48-60) peptide. Intracellular photolysis of [Tyr(DMNB)(4)]Ang-II induced an increase in nucleoplasmic Ca(2+) ([Ca(2+)]n), and initiated 18S rRNA and nuclear factor kappa B mRNA synthesis in adult cardiac cells. We conclude that caged Ang-II analogues represent powerful new tools for use in the selective study of intracrine signalling via Ang-II.
Asunto(s)
Angiotensina II/análogos & derivados , Señalización del Calcio , Receptores de Angiotensina/metabolismo , Rayos Ultravioleta , Antagonistas de Receptores de Angiotensina/farmacología , Animales , Fluoresceínas/efectos de la radiación , Colorantes Fluorescentes/efectos de la radiación , Células HEK293 , Humanos , Masculino , Microscopía Fluorescente/métodos , Ratas , Ratas Sprague-Dawley , Receptores de Angiotensina/agonistasRESUMEN
Angiotensin II (AII), an octapeptide member of the renin-angiotensin system (RAS), is formed by the enzyme angiotensin converting enzyme (ACE) and exerts adverse cellular effects through an interaction with its type 1 receptor (AT1R). Both ACE inhibitors and angiotensin receptor blockers (ARB) mitigate the vasoconstrictive, proliferative, proinflammatory, proapoptotic, and profibrotic effects of AII and are widely used as effective anti-remodeling agents in clinical practice. Prediction of individual response to these agents, however, remains problematic and is influenced by many factors including race, gender, and genotype. In addition, systemic and tissue RAS activity do not correlate closely. This report summarizes the results of on-going attempts to noninvasively determine tissue ACE activity and AT1R expression using novel nuclear tracers. It is hoped that the availability of such imaging techniques improve treatment of heart failure through more selective pharmacologic intervention and better dose titration of available drugs.
Asunto(s)
Bloqueadores del Receptor Tipo 1 de Angiotensina II/uso terapéutico , Antagonistas de Receptores de Angiotensina/uso terapéutico , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Antihipertensivos/uso terapéutico , Insuficiencia Cardíaca/tratamiento farmacológico , Receptores de Angiotensina/agonistas , Sistema Renina-Angiotensina/efectos de los fármacos , Animales , Femenino , Insuficiencia Cardíaca/diagnóstico por imagen , Insuficiencia Cardíaca/fisiopatología , Humanos , Hipertensión/tratamiento farmacológico , Masculino , Ratones , Tomografía Computarizada de Emisión de Fotón ÚnicoRESUMEN
BACKGROUND: We examined the effect of chronic administration of angiotensin IV (AngIV) on the vascular alterations induced by type 1 diabetes in mice. METHODS: Diabetes was induced in adult Swiss mice with a single injection of streptozotocin (STZ). Mice were treated subcutaneously with AngIV (1.4 mg/kg/day) either immediately following diabetes induction (preventive treatment), or treated with AngIV (0.01 to 1.4 mg/kg), alone or with the AT4 receptor antagonist Divalinal or the AT2 receptor antagonist PD123319, for two weeks after 4 weeks of diabetes duration (rescue treatment). Acetylcholine-induced, endothelium-dependent relaxation (EDR) was measured in isolated aortic rings preparations. Histomorphometric measurements of the media thickness were obtained, and nitric oxide (NO) and superoxide anion production were measured by electron paramagnetic resonance in aorta and mesenteric arteries. The effect of diabetes on mesenteric vascular alterations was also examined in genetically modified mice lacking the AT2 receptor. RESULTS: Induction of diabetes with STZ was associated with a progressive decrease of EDR and an increase of the aortic and mesenteric media thickness already significant after 4 weeks and peaking at week 6. Immediate treatment with AngIV fully prevented the diabetes-induced endothelial dysfunction. Rescue treatment with AngIV implemented after 4 weeks of diabetes dose-dependently restored a normal endothelial function at week 6. AngIV blunted the thickening of the aortic and mesenteric media, and reversed the diabetes-induced changes in NO and O2â¢- production by the vessels. The protective effect of AngIV on endothelial function was completely blunted by cotreatment with Divalinal, but not with PD123319. In contrast, both the pharmacological blockade and genetic deletion of the AT2 receptor reversed the diabetes-induced morphologic and endothelial alteration caused by diabetes. CONCLUSIONS: The results suggest an opposite contribution of AT2 and AT4 receptors to the vascular alterations caused by streptozotocin-induced diabetes in mice, since chronic stimulation of AT4 by AngIV and inhibition of AT2 similarly reverse diabetes-induced endothelial dysfunction and hypertrophic remodeling, and increase NO bioavailability.
Asunto(s)
Bloqueadores del Receptor Tipo 2 de Angiotensina II/uso terapéutico , Angiotensina II/análogos & derivados , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/fisiopatología , Receptor de Angiotensina Tipo 2/fisiología , Receptores de Angiotensina/fisiología , Angiotensina II/farmacología , Angiotensina II/uso terapéutico , Bloqueadores del Receptor Tipo 2 de Angiotensina II/farmacología , Animales , Masculino , Ratones , Ratones Noqueados , Técnicas de Cultivo de Órganos , Receptor de Angiotensina Tipo 2/agonistas , Receptores de Angiotensina/agonistas , Resultado del Tratamiento , Vasodilatación/efectos de los fármacos , Vasodilatación/fisiologíaRESUMEN
The involvement of renin-angiotensin system (RAS) and its active peptides, particularly angiotensin II (Ang II), has been described not only in hypertension, but also in stress-associated anxiety disorders. Ang II and its two subtypes of receptors, viz. AT1 and AT2, are localized on stress-responsive brain areas including the hypothalamus-adrenal-pituitary (HPA) axis. The different types of stressors increase the levels of Ang II and change the expression of its receptors. Transgenic animals with a centrally inactivated angiotensin system demonstrate increased anxiety-related behavior describing the anxiolytic effects of basal Ang II. However, studies showing the anxiolytic potential of AT1 receptor antagonists have described the anxiogenic effects of endogenously released Ang II. It suggests that the basal Ang II (in low amount) may attenuate anxiety, while stress-released Ang II (in high amount) may produce anxiety. By employing AT2-deficient mice, the functional role of AT2 receptors in attenuating stress-associated anxiety has been described. Moreover, AT1 receptor antagonists-induced anti-anxiety effects are associated with up-regulation of AT2 receptors in the brain suggesting that the centrally acting AT2 receptor agonists may serve as potential anxiolytic agents. The present review discusses the dual role of Ang II and its receptors in the development of stress-associated anxiety along with its interrelationship with benzodiazepines (BZD) receptors, and other stress mediators including corticotrophin releasing hormone (CRH) and serotonin (5-HT).
Asunto(s)
Angiotensinas/metabolismo , Trastornos de Ansiedad/metabolismo , Receptores de Angiotensina/metabolismo , Antagonistas de Receptores de Angiotensina/farmacología , Angiotensinas/genética , Animales , Trastornos de Ansiedad/tratamiento farmacológico , Trastornos de Ansiedad/genética , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Encéfalo/fisiología , Hormona Liberadora de Corticotropina/metabolismo , Humanos , Receptores de Angiotensina/agonistas , Receptores de Angiotensina/genética , Receptores de GABA-A/metabolismo , Serotonina/metabolismo , Estrés Fisiológico , Regulación hacia Arriba/efectos de los fármacosRESUMEN
UNLABELLED: The renin-angiotensin system plays a crucial role in the regulation of cardiovascular function and maintenance of water-electrolyte balance. The two major receptor types of the system, AT1 and AT2, have different, often opposite effects on these functions. AIM: To elucidate the impact of long-term treatment with selective angiotensin receptor antagonists and an agonist on water-salt balance in normotensive Wistar and spontaneously hypertensive rats (SHRs). MATERIALS AND METHODS: 12-week-old male Wistar rats and SHRs were individually housed in metabolic cages and 24-h food and water intake and urine and electrolyte excretion were measured. Urinary sodium (UNa), potassium (UK) and chlorine (UCl) were determined by a flame photometer. Losartan, a selective AT1 receptor antagonist, was administered in the Wistar rats and SHRs at a dose of 10 mg/kg/day subcutaneously (sc). Wistar rats were also given the AT2 receptor antagonist, PD123319, subcutaneously at a dose of 10 mg/kg/ day. CGP 42112A, an AT2 receptor agonist, was administered intracerebroventricularly in Wistar rats at a dose of 12 microg/rat/day. The drugs were infused continuously for 14 days through osmotic minipumps. RESULTS: Losartan selectively increased sodium excretion in both rat strains and decreased weight gain in SHRs. PD123319 increased potassium excretion and decreased weight gain in Wistar rats. CGP 42112A increased food and water intake, urine output and UNa+ and UK+ excretion and decreased weight gain in normotensive Wistar rats. CONCLUSIONS: Chronic treatment with selective angiotensin receptor ligands modifies water-salt balance in rats through changes both in renal excretory function and ingestive behaviors.
Asunto(s)
Antagonistas de Receptores de Angiotensina/farmacología , Receptores de Angiotensina/agonistas , Equilibrio Hidroelectrolítico/efectos de los fármacos , Animales , Peso Corporal/efectos de los fármacos , Ingestión de Líquidos/efectos de los fármacos , Ingestión de Alimentos/efectos de los fármacos , Masculino , Oligopéptidos/farmacología , Ratas , Ratas Endogámicas SHR , Ratas WistarRESUMEN
Angiotensin II type I receptor agonistic autoantibodies (AT1-AA) are related to pre-eclampsia and hypertension and have a direct effect of stimulating the production of tumor necrosis factor-alpha (TNF-α) in the placenta. TNF-α is a known mediator of apoptosis. However, few studies have reported the role of TNF-α and its relationship within AT1-AA-induced apoptosis of cardiomyocytes. In this study, neonatal rat cardiomyocytes were treated with various concentrations of AT1-AA. The apoptosis of neonatal rat cardiomyocytes was determined using TUNEL assay and flow cytometry. The level of secreted TNF-α was measured by enzyme-linked immunosorbent assay, and caspase-3 activity was measured by a fluorogenic protease assay kit. AT1 receptor blockade and TNF inhibitor were added to determine whether they could inhibit the apoptotic effect of AT1-AA. Results showed that AT1-AA induced the apoptosis of neonatal rat cardiomyocytes in a dose-dependent and time-dependent manner. AT1-AA increased TNF secretion and caspase-3 activities. AT1 receptor blockade completely abrogated AT1-AA-induced TNF-α secretion, caspase-3 activation, and cardiomyocyte apoptosis. TNF-α receptor inhibitor significantly attenuated AT1-AA-induced neonatal rat cardiomyocyte apoptosis. AT1-AA in the plasma of pre-eclamptic patients promoted neonatal rat cardiomyocyte apoptosis through a TNF-caspase signaling pathway.
Asunto(s)
Apoptosis/inmunología , Autoanticuerpos/inmunología , Miocitos Cardíacos/inmunología , Receptores de Angiotensina/inmunología , Factor de Necrosis Tumoral alfa/inmunología , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Animales , Animales Recién Nacidos , Apoptosis/efectos de los fármacos , Autoanticuerpos/sangre , Autoanticuerpos/farmacología , Caspasa 3/inmunología , Caspasa 3/metabolismo , Células Cultivadas , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Activación Enzimática/inmunología , Ensayo de Inmunoadsorción Enzimática , Femenino , Citometría de Flujo , Humanos , Etiquetado Corte-Fin in Situ , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Preeclampsia/sangre , Preeclampsia/inmunología , Embarazo , Ratas , Receptores de Angiotensina/agonistas , Receptores de Angiotensina/metabolismo , Factores de Tiempo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Our interest focused on an open question whether AT-(1-7), nonpeptide receptor agonist: AVE 0991, is able to ameliorate atherosclerosis. We used an apolipoprotein E (apoE) - knockout mice model of atherosclerosis. Experimental groups received the same diet as control, mixed with: AVE 0991 at a dose of 0.58 µmol/kg b.w./day, perindopril at a dose of 0.4 mg/kg b.w./day or with tiorphan at a dose of 2.5 mg/kg b.w./day. A-779 [(D-alanine)-angiotensin (1-7)] was given at a dose of 3.3 mg/kg b.w., 3 times a week i.p. Measured by "en face" method, the percentage of occupied by Sudan IV-stained surfaces were as follows: 14.2±1.9 % in control group, whereas in AVE 0991-treated as well as in perindopril-treated groups percentages were statistically significantly lower. In tiorphan group there was no change comparing to control group, whereas in A-779 group percentage was statistically significantly higher. "Cross-section" of aortic roots revealed also the difference in atherosclerotic lesions. The mean surfaces, occupied by oil red O-stained changes were: 91.213±8.123 µm(2) in control group, while in AVE 0991-treated as well as in perindopril-treated groups lesions were statistically significantly lower. In tiorphan group there was no change; however, in A-779 group lesions were statistically significantly higher. Measured by real time RT-PCR relative p22phox (submit of NADPH oxidase) expression was significantly decreased in AVE 0991-treated mice. As revealed by flow cytometry, the expression of co-stimulatory molecules: CD86, CD80 and CD40 on both dendritic cells (CD11c+) and macrophages (F4/80+) was reduced in AVE 0991-treated group, which correlated with decreased expression of CD69 activation marker on CD4+T cells. In our report we showed the beneficial effect of AVE 0991 on atherogenesis in gene-targeted mice.
Asunto(s)
Angiotensina I/agonistas , Apolipoproteínas E/deficiencia , Aterosclerosis/tratamiento farmacológico , Imidazoles/farmacología , Fragmentos de Péptidos/agonistas , Proteínas Proto-Oncogénicas/agonistas , Receptores de Angiotensina/agonistas , Receptores Acoplados a Proteínas G/agonistas , Angiotensina I/metabolismo , Animales , Antígenos CD/metabolismo , Aorta/efectos de los fármacos , Aorta/metabolismo , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Aterosclerosis/genética , Aterosclerosis/metabolismo , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD4-Positivos/metabolismo , Células Dendríticas/efectos de los fármacos , Células Dendríticas/metabolismo , Femenino , Lípidos/sangre , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fragmentos de Péptidos/metabolismo , Perindopril/farmacología , Proto-Oncogenes Mas , Proteínas Proto-Oncogénicas/metabolismo , Receptores de Angiotensina/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Tiorfan/farmacologíaRESUMEN
beta-Arrestins, which were originally characterized as terminators of heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptor (GPCR) signaling, also act as important signal transducers. An emerging concept in GPCR signaling is beta-arrestin-biased agonism, in which specific ligand-activated GPCR conformational states selectively signal through beta-arrestins, rather than through G proteins. Here, we show that mechanical stretch induced beta-arrestin-biased signaling downstream of angiotensin II type I receptors (AT1Rs) in the absence of ligand or G protein activation. Mechanical stretch triggered an AT1R-mediated conformational change in beta-arrestin similar to that induced by a beta-arrestin-biased ligand to selectively stimulate receptor signaling in the absence of detectable G protein activation. Hearts from mice lacking beta-arrestin or AT1Rs failed to induce responses to mechanical stretch, as shown by blunted extracellular signal-regulated kinase and Akt activation, impaired transactivation of the epidermal growth factor receptor, and enhanced myocyte apoptosis. These data show that the heart responds to acute increases in mechanical stress by activating beta-arrestin-mediated cell survival signals.
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Arrestinas/fisiología , Receptores de Angiotensina/agonistas , Estrés Mecánico , Animales , Arrestinas/química , Humanos , Ratones , Conformación Proteica , Transporte de Proteínas , Receptores de Angiotensina/metabolismo , beta-ArrestinasRESUMEN
INTRODUCTION: The effects of angiotensin (Ang) IV result from binding to a constitutively active metallopeptidase known as the AT(4) receptor (or oxytocinase/insulin-regulated membrane aminopeptidase). While in vitro evidence indicates that Ang IV inhibits the peptidase activity of AT(4) receptors, leading to increases in the concentrations of several peptides, including oxytocin, the consequence of inhibiting AT(4) peptidase activity in vivo remains unresolved. DISCUSSION: Microdialysis coupled to immunoassay techniques revealed that systemic and intra-amygdala injection of Nle-Ang IV, a metabolically stable derivative of Ang IV, significantly elevated extracellular levels of oxytocin in the rat amygdala. Based on earlier reports describing the anxiolytic-like effects of oxytocin, we investigated whether disrupting AT(4) peptidase activity would yield similar responses. In the mouse four-plate test, acute treatment with either Nle-Ang IV or LVV-hemorphin-7, a related AT(4) receptor ligand, elicited significant increases in the number of punished crossings. These behavioral responses were comparable to the anxiolytic-like effects of oxytocin and to the standard anxiolytic agent, chlordiazepoxide. Cotreatment with either the AT(4) receptor antagonist, divalinal, or the selective oxytocin receptor antagonist, WAY-162720, reversed the anxiolytic-like effects of Nle-Ang IV, while combining ineffective doses of Nle-Ang IV and oxytocin increased the number of punished crossings in this assay. Conversely, Nle-Ang IV and LVV-hemorphin-7 were inactive in the mouse tail suspension test of antidepressant activity. These findings represent the first in vivo demonstration of the peptidase activity of AT(4) receptors, confirm the anxiolytic-like properties of Ang IV, and reveal a unique and previously uncharacterized relationship between AT(4) and oxytocin receptor systems.
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Amígdala del Cerebelo/efectos de los fármacos , Angiotensina II/análogos & derivados , Ansiolíticos/administración & dosificación , Ansiedad/prevención & control , Oxitocina/metabolismo , Receptores de Angiotensina/agonistas , Receptores de Oxitocina/agonistas , Amígdala del Cerebelo/metabolismo , Angiotensina II/administración & dosificación , Antagonistas de Receptores de Angiotensina , Animales , Ansiedad/metabolismo , Ansiedad/psicología , Conducta Animal/efectos de los fármacos , Depresión/tratamiento farmacológico , Depresión/metabolismo , Depresión/psicología , Relación Dosis-Respuesta a Droga , Conducta Exploratoria/efectos de los fármacos , Hemoglobinas/administración & dosificación , Inmunoensayo , Inyecciones Intraperitoneales , Inyecciones Intraventriculares , Inyecciones Subcutáneas , Ligandos , Masculino , Ratones , Microdiálisis , Fragmentos de Péptidos/administración & dosificación , Ratas , Ratas Sprague-Dawley , Receptores de Angiotensina/metabolismo , Receptores de Oxitocina/antagonistas & inhibidores , Receptores de Oxitocina/metabolismo , Factores de Tiempo , Regulación hacia ArribaRESUMEN
We have recently found that postsynaptic D3 dopamine (DA) receptors appear not to participate in the memory enhancing effects of the angiotensin AT4 receptor agonists angiotensin IV (Ang IV) and des-Phe(6)-Ang IV. In this study we evaluated role of the presynaptic DA D3 receptors in these effects. For that purpose effect of (+)-UH 232, a selective D3 DA receptors partial agonist preferring presynaptic sites, on the pro-cognitive action of intracerebroventricularly (icv) injected Ang IV and des-Phe(6)-Ang IV was examined. Male Wistar rats weighing 180-200 g were used. Both peptides given at the dose of 1 nmol facilitated recall of a passive avoidance (PA) behaviour, improved object recognition (OR), and increased apomorphine-induced stereotype behaviour. In the auxiliary tests performed to control for the unspecific influence of motor (open field, OF) and emotional ('plus' maze, PM) effects of our treatments on the results of the memory tests they had either no (OF) or negligible (PM) effects. Intraperitoneal pre-treatment of the animals with an ineffective on its own dose (1 mg/kg) of (+)-UH 232 abolished or markedly diminished effects of both peptides on PA and OR but did not influence enhancement of stereotypy caused by the peptides.
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8-Hidroxi-2-(di-n-propilamino)tetralin/análogos & derivados , Angiotensina II/análogos & derivados , Cognición/efectos de los fármacos , Antagonistas de Dopamina/farmacología , Agonismo Parcial de Drogas , Receptores de Dopamina D3/agonistas , 8-Hidroxi-2-(di-n-propilamino)tetralin/antagonistas & inhibidores , 8-Hidroxi-2-(di-n-propilamino)tetralin/farmacología , Angiotensina II/antagonistas & inhibidores , Angiotensina II/farmacología , Antagonistas de Receptores de Angiotensina , Animales , Apomorfina/farmacología , Reacción de Prevención/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Conducta Exploratoria/efectos de los fármacos , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Ratas , Receptores de Angiotensina/agonistas , Receptores de Dopamina D3/antagonistas & inhibidores , Reconocimiento en Psicología/efectos de los fármacos , Conducta Estereotipada/efectos de los fármacosRESUMEN
The medical treatment of glaucoma has undergone significant development in recent years. Research in this field is focused on improving pre-existing drugs and on the development of new molecules. In relation to commercial drugs, there is a trend to improve local tolerance, using less toxic preservatives as in the case of sofZIA in travoprost, and eliminating the preservatives as in tafluprost. The development of new, fixed combinations of commercial drugs could also enhance their administration and therapeutic compliance. There is also intense research activity in the search for new therapeutic groups for glaucoma treatment. Calcium channel-blockers such as lomerizine do not seem to affect systemic hypotension, while topical calcium-blockers like flunarizine and iganidipine are also under research. Endothelin 1 antagonists such as sulfisoxazole and bunazosine could be also useful in the treatment of glaucoma. In the renin angiotensin system, angiotensin (1-7) and olmesartan are under investigation for use in glaucoma patients. Trabecular drugs such as Rho-kinase inhibitors could be effective on the pathogenic mechanism of primary open angle glaucoma. Finally, topical mifepristone, an antagonist of glucocorticoid receptors, is under evaluation for corticosteroid-induced elevated intraocular pressure (Arch Soc Esp Oftalmol 2009; 84: 491-500).
Asunto(s)
Glaucoma/tratamiento farmacológico , Antagonistas de Receptores de Angiotensina , Bloqueadores de los Canales de Calcio/uso terapéutico , Endotelinas/antagonistas & inhibidores , Humanos , Prostaglandinas/agonistas , Receptores de Angiotensina/agonistasRESUMEN
Only few studies have been devoted to the actions of the renin-angiotensin system (RAS) in the human gastrointestinal tract. The present study was undertaken to elucidate the expression and action of RAS in the human esophageal mucosa. Mucosal specimens with normal histological appearance were obtained from healthy subjects undergoing endoscopy and from patients undergoing esophagectomy due to neoplasm. Gene and protein expressions of angiotensin II (Ang II) receptor type 1 (AT(1)) and type 2 (AT(2)) and angiotensin-converting enzyme (ACE) were analyzed. In vivo functionality in healthy volunteers was reflected by assessing transmucosal potential difference (PD). Ussing chamber technique was used to analyze the different effects of Ang II on its AT(1) and AT(2) receptors. Immunoreactivity to AT(1) and AT(2) was localized to stratum superficiale and spinosum in the epithelium. ACE, AT(1), and AT(2) were found in blood vessel walls. Transmucosal PD in vivo increased following administration of the AT(1) receptor antagonist candesartan. In Ussing preparations mean basal transmural PD was -6.4 mV, epithelial current (I(ep)) 34 muA/cm(2), and epithelial resistance (R(ep)) 321 Omega.cm(2). Serosal exposure to Ang II increased PD as a result of increased I(ep), whereas R(ep) was constant. Ang II given together with the selective AT(1)-receptor antagonist losartan, or AT(2) agonist C21 given alone, resulted in a similar effect. Ang II given in presence of the AT(2)-receptor antagonist PD123319 did not influence PD, but I(ep) decreased and R(ep) increased. In conclusion, Ang II receptors and ACE are expressed in the human esophageal epithelium. The results suggest that AT(2)-receptor stimulation increases epithelial ion transport, whereas the AT(1) receptor inhibits ion transport and increases R(ep).
Asunto(s)
Esófago/metabolismo , Membrana Mucosa/metabolismo , Receptores de Angiotensina/metabolismo , Adulto , Angiotensina II/farmacología , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Bloqueadores del Receptor Tipo 2 de Angiotensina II , Antagonistas de Receptores de Angiotensina , Bencimidazoles/farmacología , Biopsia , Compuestos de Bifenilo , Vasos Sanguíneos/metabolismo , Impedancia Eléctrica , Fenómenos Electrofisiológicos/efectos de los fármacos , Fenómenos Electrofisiológicos/fisiología , Células Epiteliales/metabolismo , Esófago/citología , Femenino , Expresión Génica/genética , Humanos , Ácido Clorhídrico/farmacología , Imidazoles/farmacología , Losartán/farmacología , Masculino , Persona de Mediana Edad , Membrana Mucosa/citología , Membrana Mucosa/efectos de los fármacos , Peptidil-Dipeptidasa A/genética , Peptidil-Dipeptidasa A/metabolismo , Piridinas/farmacología , Receptor de Angiotensina Tipo 1/genética , Receptor de Angiotensina Tipo 1/metabolismo , Receptor de Angiotensina Tipo 2/agonistas , Receptor de Angiotensina Tipo 2/genética , Receptor de Angiotensina Tipo 2/metabolismo , Receptores de Angiotensina/agonistas , Tetrazoles/farmacologíaRESUMEN
The insulin-regulated aminopeptidase/AT(4) receptor has recently emerged as a new target for pharmaceutical agents aimed at treating various cognitive disorders such as Alzheimer's disease. There is an unmet need for metabolically stable drug-like angiotensin (Ang) IV analogues that exert actions mimicking the powerful memory-enhancing effects of Ang IV and LVV-hemorphin-7 and can efficiently cross the blood-brain barrier. Such new chemical entities would be attractive as research tools and would allow extensive study of the impact of Ang IV on in vivo physiology in complex animal models. Drug-like Ang IV peptidomimetics are foreseen to serve as potential lead structures for further optimization in drug discovery.
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Angiotensina II/análogos & derivados , Antagonistas de Receptores de Angiotensina , Trastornos del Conocimiento/tratamiento farmacológico , Cistinil Aminopeptidasa/antagonistas & inhibidores , Receptores de Angiotensina/agonistas , Enfermedad de Alzheimer/tratamiento farmacológico , Angiotensina II/metabolismo , Angiotensina II/farmacología , Angiotensina II/uso terapéutico , Animales , Sistemas de Liberación de Medicamentos , Descubrimiento de Drogas , Humanos , Ligandos , Modelos Biológicos , Estructura MolecularRESUMEN
We previously demonstrated that Ang II inhibits the renal plasma membrane Ca(2+)-ATPase. In the present work we have studied the effect of Ang II, at concentrations similar to those found in the renal interstitium, on the Ca(2+)-ATPase from proximal tubule cells. High Ang II concentration (5 x 10(-7) mol/L) led to the recovery of Ca(2+)-ATPase activity previously inhibited by 50% at low Ang II concentration (10(-10) mol/L). Reactivation occurred in parallel with: (i) formation of only two dead-end metabolites [Ang-(3-4) and Tyr] after incubation of isolated membranes with micromolar Ang II; and (ii) dissociation of constitutive AT(1)R/AT(2)R heterodimers, which are preserved with 10(-10) mol/L Ang II. When the membranes were incubated with 10(-14) mol/L Ang-(3-4), inhibition by 10(-10) mol/L Ang II was no longer observed. The counteracting effect of Ang-(3-4) was abolished by PD123319, an antagonist of AT(2)R, and mimicked by CGP42112A, an agonist of AT(2)R. Ang-(1-7) is an intermediate in the formation of Ang-(3-4) via a pathway involving angiotensin-converting enzyme (ACE), and complete dipeptide breakdown to Tyr and Val is impaired by low Ang II. We conclude that Ang-(3-4) may be a physiological regulator of active Ca(2+) fluxes in renal proximal cells by acting within the renin-angiotensin axis.
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Angiotensina II/metabolismo , Angiotensina II/farmacología , ATPasas Transportadoras de Calcio/metabolismo , Membrana Celular/enzimología , Riñón/enzimología , Fragmentos de Péptidos/metabolismo , Fragmentos de Péptidos/fisiología , Antagonistas de Receptores de Angiotensina , Animales , Cromatografía Líquida de Alta Presión , Activación Enzimática/efectos de los fármacos , Imidazoles/farmacología , Técnicas In Vitro , Oligopéptidos/farmacología , Piridinas/farmacología , Receptores de Angiotensina/agonistas , Receptores de Angiotensina/metabolismo , Ovinos , Espectrometría de Masa por Ionización de Electrospray , Vasoconstrictores/farmacologíaRESUMEN
Angiotensin-(1-7) [Ang-(1-7)] is a vasodilator peptide with cardiac and vascular protective properties. We examined the influence of Ang-(1-7), both endogenous and after chronic treatment with the peptide (576microg/(kgday)), on ischemia/reperfusion (I/R)-induced cardiac dysfunction in streptozotocin-treated spontaneously hypertensive rats (diabetic SHR). In isolated perfused hearts, recovery of left ventricular function from 40min of global ischemia was improved significantly in Ang-(1-7)- or captopril-treated diabetic SHR and worsened in animals treated with A779, an Ang-(1-7) receptor (AT((1-7))) antagonist. The beneficial effect of captopril on cardiac recovery was reduced when co-administered with A779. Cardiac NF-kappaB activity appears to be higher in diabetic SHR and treatment with Ang-(1-7) or captopril decreased NF-kappaB activity in diabetic SHR, an effect partially reversed by co-administration of A779. Real-time PCR-based gene array analysis of cardiac tissue revealed that Ang-(1-7) or captopril treatment may reduce expression of several genes of inflammation involved in the NF-kappaB signalling pathway. The data provide for the first time a role for endogenous Ang-(1-7) as well as confirmation that exogenous treatment with the peptide produces cardioprotection. Whether potential anti-inflammatory and transcriptional factor changes are directly linked to the cardioprotection produced by Ang-(1-7) in diabetic SHR remains to be determined.
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Angiotensina I/fisiología , Angiotensina I/uso terapéutico , Corazón/efectos de los fármacos , Daño por Reperfusión Miocárdica/tratamiento farmacológico , Fragmentos de Péptidos/fisiología , Fragmentos de Péptidos/uso terapéutico , Angiotensina I/administración & dosificación , Angiotensina I/antagonistas & inhibidores , Angiotensina II/administración & dosificación , Angiotensina II/análogos & derivados , Angiotensina II/uso terapéutico , Antagonistas de Receptores de Angiotensina , Animales , Presión Sanguínea/efectos de los fármacos , Captopril/administración & dosificación , Captopril/uso terapéutico , Diabetes Mellitus Experimental/fisiopatología , Quimioterapia Combinada , Corazón/fisiopatología , Técnicas In Vitro , Masculino , Miocardio/enzimología , FN-kappa B/metabolismo , Proteínas Nucleares/metabolismo , Fragmentos de Péptidos/administración & dosificación , Fragmentos de Péptidos/antagonistas & inhibidores , ARN Mensajero/metabolismo , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY , Receptores de Angiotensina/agonistas , Transducción de Señal/efectos de los fármacosRESUMEN
Novokinin (Arg-Pro-Leu-Lys-Pro-Trp) is a vasorelaxing and hypotensive peptide acting through the angiotensin AT(2) receptor. Centrally administrated novokinin (30nmol/mouse) inhibited the antinociceptive effect of micro agonist morphine in mice, as evaluated by the tail-pinch test. The anti-opioid effect of novokinin was blocked by PD123319, an antagonist of the AT(2) receptor. Angiotensin II (0.01nmol/mouse, i.c.v.) and [p-aminophenylalanine(6)]-angiotensin II [p-NH(2)Phe(6)]-Ang II (0.1nmol/mouse, i.c.v.), a highly selective AT(2) receptor agonist, also inhibited the antinociceptive effect of morphine, and the effects were also blocked by PD123319. Angiotensin II did not suppress the antinociceptive effect induced by kappa or delta agonists. Novokinin, angiotensin II and [p-NH(2)Phe(6)]-Ang did not have affinity for the micro receptor. The anti-opioid effects induced by these peptides were blocked by ONO-AE3-240, an antagonist of the EP(3) receptor. These results suggest that the anti-opioid effects of AT(2) agonists are mediated by the PGE(2)-EP(3) receptor system downstream of the AT(2) receptor.