RESUMEN
Mutating the side-chains of amino acids in a peptide ligand, with unnatural amino acids, aiming to mitigate its short half-life is an established approach. However, it is hypothesized that mutating specific backbone peptide bonds with bioisosters can be exploited not only to enhance the proteolytic stability of parent peptides, but also to tune its receptor subtype selectivity. Towards this end, four [Y]6 -Angiotensin II analogues are synthesized where amide bonds have been replaced by 1,4-disubstituted 1,2,3-triazole isosteres in four different backbone locations. All the analogues possessed enhanced stability in human plasma in comparison with the parent peptide, whereas only two of them achieved enhanced AT2 R/AT1 R subtype selectivity. This diversification has been studied through 2D NMR spectroscopy and unveiled a putative more structured microenvironment for the two selective ligands accompanied with increased number of NOE cross-peaks. The most potent analogue, compoundâ 2, has been explored regarding its neurotrophic potential and resulted in an enhanced neurite growth with respect to the established agent C21.
Asunto(s)
Angiotensina II/química , Angiotensina II/metabolismo , Mutación , Péptidos/genética , Receptores de Angiotensina/química , Receptores de Angiotensina/metabolismo , Aminoácidos/genética , Angiotensina II/genética , Animales , Células HEK293 , Humanos , Ligandos , Péptidos/química , Péptidos/metabolismo , Especificidad por SustratoRESUMEN
The angiotensin II receptor AGTR1, which mediates vasoconstrictive and inflammatory signaling in vascular disease, is overexpressed aberrantly in some breast cancers. In this study, we established the significance of an AGTR1-responsive NFκB signaling pathway in this breast cancer subset. We documented that AGTR1 overexpression occurred in the luminal A and B subtypes of breast cancer, was mutually exclusive of HER2 expression, and correlated with aggressive features that include increased lymph node metastasis, reduced responsiveness to neoadjuvant therapy, and reduced overall survival. Mechanistically, AGTR1 overexpression directed both ligand-independent and ligand-dependent activation of NFκB, mediated by a signaling pathway that requires the triad of CARMA3, Bcl10, and MALT1 (CBM signalosome). Activation of this pathway drove cancer cell-intrinsic responses that include proliferation, migration, and invasion. In addition, CBM-dependent activation of NFκB elicited cancer cell-extrinsic effects, impacting endothelial cells of the tumor microenvironment to promote tumor angiogenesis. CBM/NFκB signaling in AGTR1+ breast cancer therefore conspires to promote aggressive behavior through pleiotropic effects. Overall, our results point to the prognostic and therapeutic value of identifying AGTR1 overexpression in a subset of HER2-negative breast cancers, and they provide a mechanistic rationale to explore the repurposing of drugs that target angiotensin II-dependent NFκB signaling pathways to improve the treatment of this breast cancer subset.Significance: These findings offer a mechanistic rationale to explore the repurposing of drugs that target angiotensin action to improve the treatment of AGTR1-expressing breast cancers. Cancer Res; 78(5); 1225-40. ©2017 AACR.
Asunto(s)
Proteína 10 de la LLC-Linfoma de Células B/metabolismo , Neoplasias de la Mama/patología , Proteínas Adaptadoras de Señalización CARD/metabolismo , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/metabolismo , FN-kappa B/metabolismo , Receptor de Angiotensina Tipo 1/metabolismo , Receptores de Angiotensina/metabolismo , Animales , Apoptosis , Proteína 10 de la LLC-Linfoma de Células B/antagonistas & inhibidores , Proteína 10 de la LLC-Linfoma de Células B/genética , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Proteínas Adaptadoras de Señalización CARD/antagonistas & inhibidores , Proteínas Adaptadoras de Señalización CARD/genética , Movimiento Celular , Proliferación Celular , Embrión de Pollo , Femenino , Estudios de Seguimiento , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Ratones Desnudos , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/antagonistas & inhibidores , Proteína 1 de la Translocación del Linfoma del Tejido Linfático Asociado a Mucosas/genética , FN-kappa B/genética , Neovascularización Patológica , Pronóstico , ARN Interferente Pequeño/genética , Receptor de Angiotensina Tipo 1/genética , Receptores de Angiotensina/química , Receptores de Angiotensina/genética , Tasa de Supervivencia , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Background: Blockade of the renin-angiotensin-aldosterone system (RAAS) retards progression of chronic kidney disease. Yet, in many patients, the renoprotective effect is incomplete. A high circulating level of the phosphaturic hormone fibroblast growth factor 23 is associated with an impaired response to RAAS blockade-based therapy in clinical studies. Therefore, we addressed whether administration of recombinant fibroblast growth factor 23 (FGF23) interferes with the efficacy of angiotensin receptor blocker (ARB) treatment in a mouse model of renal fibrosis [unilateral ureteral obstruction (UUO)]. Methods: UUO mice were treated with losartan (100 mg/L in drinking water), recombinant FGF23 (160 ng/kg i.p. twice daily), their combination or vehicle ( n = 10 per group). Seven days after the UUO procedure, kidney tissue was analyzed for markers of RAAS activity, inflammation and fibrosis using real-time PCR and immunohistochemistry. Results: In the contralateral (non-affected) kidneys of ARB-treated UUO mice, administration of FGF23 reversed the induction of renin, ACE, ACE2 and AT1 receptor mRNA expression, suggesting interference with the physiological response to RAAS blockade by FGF23. Furthermore, recombinant FGF23 infusion prevented ARB-induced klotho upregulation in contralateral kidneys. In the UUO kidneys, klotho was majorly reduced in all groups. Pro-inflammatory gene expression (MCP-1, TNF-α) induced in UUO kidneys was reduced by ARB treatment; this anti-inflammatory effect was reversed by FGF23. In contrast, ARB-induced reduction of (pre-)fibrotic gene expression was not reversed by FGF23. Conclusions: Our findings show pharmacological interaction between exogenous FGF23 and losartan, thus serving as a proof of principle for crosstalk between the FGF23-klotho axis and RAAS.
Asunto(s)
Aldosterona/metabolismo , Factores de Crecimiento de Fibroblastos/farmacología , Fibrosis/tratamiento farmacológico , Losartán/farmacología , Receptores de Angiotensina/química , Sistema Renina-Angiotensina/efectos de los fármacos , Obstrucción Ureteral/tratamiento farmacológico , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Animales , Modelos Animales de Enfermedad , Factor-23 de Crecimiento de Fibroblastos , Fibrosis/metabolismo , Fibrosis/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Receptores de Angiotensina/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Obstrucción Ureteral/metabolismo , Obstrucción Ureteral/patologíaRESUMEN
CARD9 is a central component of anti-fungal innate immune signaling via C-type lectin receptors, and several immune-related disorders are associated with CARD9 alterations. Here, we used a rare CARD9 variant that confers protection against inflammatory bowel disease as an entry point to investigating CARD9 regulation. We showed that the protective variant of CARD9, which is C-terminally truncated, acted in a dominant-negative manner for CARD9-mediated cytokine production, indicating an important role for the C terminus in CARD9 signaling. We identified TRIM62 as a CARD9 binding partner and showed that TRIM62 facilitated K27-linked poly-ubiquitination of CARD9. We identified K125 as the ubiquitinated residue on CARD9 and demonstrated that this ubiquitination was essential for CARD9 activity. Furthermore, we showed that similar to Card9-deficient mice, Trim62-deficient mice had increased susceptibility to fungal infection. In this study, we utilized a rare protective allele to uncover a TRIM62-mediated mechanism for regulation of CARD9 activation.
Asunto(s)
Proteínas Adaptadoras de Señalización CARD/fisiología , Candidiasis Invasiva/inmunología , Receptores de Angiotensina/fisiología , Receptores de Endotelina/fisiología , Ubiquitina-Proteína Ligasas/fisiología , Adyuvantes Inmunológicos/farmacología , Animales , Proteínas Adaptadoras de Señalización CARD/química , Proteínas Adaptadoras de Señalización CARD/deficiencia , Proteínas Adaptadoras de Señalización CARD/genética , Candidiasis Invasiva/genética , Colitis/inducido químicamente , Colitis/genética , Colitis/prevención & control , Citocinas/biosíntesis , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Genes Dominantes , Predisposición Genética a la Enfermedad , Células HEK293 , Células HeLa , Humanos , Enfermedades Inflamatorias del Intestino/genética , Ratones , Ratones de la Cepa 129 , Ratones Noqueados , Mapeo de Interacción de Proteínas , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/fisiología , Procesamiento Proteico-Postraduccional , Estructura Terciaria de Proteína , Receptores de Angiotensina/química , Receptores de Angiotensina/deficiencia , Receptores de Endotelina/química , Receptores de Endotelina/deficiencia , Proteínas Recombinantes de Fusión/metabolismo , Transducción de Señal , Organismos Libres de Patógenos Específicos , Proteínas de Motivos Tripartitos , Ubiquitina-Proteína Ligasas/química , UbiquitinaciónRESUMEN
The use of angiotensin receptor blockers (ARBs) for treatment of ocular diseases associated with neovascularizations, such as proliferative diabetic retinopathy, shows tremendous promise but is presently limited due to short intravitreal half-life. Conjugation of ARB molecules to branched polymers could vastly augment their therapeutic efficacy. EXP3174, a potent non-peptide ARB, was conjugated to branched poly(ethylene glycol) (PEG) and poly(amido amine) (PAMAM) dendrimers: 7.8 ligand molecules were tethered to each 40 kDa PEG molecule whereas 16.7 ligand molecules were linked to each PAMAM generation 5 dendrimer. The multivalent PEG and PAMAM conjugates blocked AT1R signaling with an IC50 of 224 and 36.3 nM, respectively. The 6-fold higher affinity of the multivalent ligand-conjugated PAMAM dendrimers was due to their unique microarchitecture and ability to suppress polymer-drug interactions. Remarkably, both polymer-drug conjugates exhibited no cytotoxicity, in stark contrast to plain PAMAM dendrimers. With sufficiently long vitreous half-lives, both synthesized polymer-ARB conjugates have the potential to pave a new path for the therapy of ocular diseases accompanied by retinal neovascularizations.
Asunto(s)
Dendrímeros/química , Sistemas de Liberación de Medicamentos , Imidazoles/farmacología , Mesodermo/efectos de los fármacos , Polímeros/química , Receptores de Angiotensina/química , Tetrazoles/farmacología , Animales , Antihipertensivos/química , Antihipertensivos/farmacología , Células Cultivadas , Portadores de Fármacos/química , Semivida , Imidazoles/química , Ligandos , Losartán , Mesodermo/citología , Mesodermo/metabolismo , Poliaminas/química , Polietilenglicoles/química , Ratas , Tetrazoles/químicaRESUMEN
We have previously shown that individual ß-amino acid substitution in angiotensin (Ang) II reduced Ang II type 1 receptor (AT1R) but not Ang II type 2 receptor (AT2R)-binding and that the heptapeptide Ang III exhibited greater AT2R:AT1R selectivity than Ang II. Therefore, we hypothesized that ß-amino-acid-substituted Ang III peptide analogues would yield highly selective AT2R ligands, which we have tested in binding and functional vascular assays. In competition binding experiments using either AT1R- or AT2R-transfected human embryonic kidney (HEK)-293 cells, novel ß-substituted Ang III analogues lacked appreciable AT1R affinity, whereas most compounds could fully displace (125)I-Sar(1)Ile(8) Ang II from AT2R. The rank order of affinity at AT2R was CGP42112 > Ang III > ß-Pro(7) Ang III=Ang II > ß-Tyr(4) Ang III ≥ PD123319 >> ß-Phe(8) Ang III >> ß Arg(2) Ang III=ß-Val(3) Ang III >> ß-Ile(5) Ang III. The novel analogue ß-Pro(7) Ang III was the most selective AT2R ligand tested, which was >20,000-fold more selective for AT2R than AT1R. IC50 values at AT2R from binding studies correlated with maximum vasorelaxation in mouse aortic rings. Given that ß-Pro(7) Ang III was an AT2R agonist, we compared ß-Pro(7) Ang III and native Ang III for their ability to reduce blood pressure in separate groups of conscious spontaneously hypertensive rats. Whereas Ang III alone increased mean arterial pressure (MAP), ß-Pro(7) Ang III had no effect. During low-level AT1R blockade, both Ang III and ß-Pro(7) Ang III, but not Ang II, lowered MAP (by â¼30 mmHg) at equimolar infusions (150 pmol/kg/min for 4 h) and these depressor effects were abolished by the co-administration of the AT2R antagonist PD123319. Thus, ß-Pro(7) Ang III has remarkable AT2R selectivity determined in binding and functional studies and will be a valuable research tool for insight into AT2R function and for future drug development.
Asunto(s)
Bloqueadores del Receptor Tipo 2 de Angiotensina II/farmacología , Angiotensina III/análogos & derivados , Hipertensión/tratamiento farmacológico , Imidazoles/farmacología , Piridinas/farmacología , Vasoconstrictores/farmacología , Secuencia de Aminoácidos , Análisis de Varianza , Angiotensina III/sangre , Angiotensina III/farmacología , Animales , Aorta Torácica/efectos de los fármacos , Aorta Torácica/fisiopatología , Bencimidazoles/metabolismo , Unión Competitiva , Compuestos de Bifenilo , Estabilidad de Medicamentos , Células HEK293 , Humanos , Técnicas In Vitro , Concentración 50 Inhibidora , Contracción Isométrica/efectos de los fármacos , Masculino , Ratones , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/fisiopatología , Ratas , Receptores de Angiotensina/química , Receptores de Angiotensina/metabolismo , Tetrazoles/metabolismo , Vasodilatación/efectos de los fármacosRESUMEN
A nanogel combined with a molecularly imprinted polymer (MIP-nanogel) receptor was prepared using the specificity determinant as a template in aqueous media. The artificial receptor can serve as the selective recognition element for angiotensins I and II and a novel way to control hypertension was investigated.
Asunto(s)
Angiotensina II/metabolismo , Angiotensina I/metabolismo , Receptores de Angiotensina/química , Receptores de Angiotensina/metabolismo , Angiotensina II/farmacología , Animales , Presión Sanguínea , Ligandos , Impresión Molecular , Nanoestructuras , RatasRESUMEN
BACKGROUND: Using either an angiotensin-converting enzyme inhibitor (ACEi) or an angiotensin receptor blocker (ARB) the morning of surgery may lead to 'functional' postoperative acute kidney injury (AKI), measured by an abrupt increase in serum creatinine. Whether the same is true for 'structural' AKI, measured with new urinary biomarkers, is unknown. METHODS: The TRIBE-AKI study was a prospective cohort study of 1594 adults undergoing cardiac surgery at six hospitals between July 2007 and December 2010. We classified the degree of exposure to ACEi/ARB into three categories: 'none' (no exposure prior to surgery), 'held' (on chronic ACEi/ARB but held on the morning of surgery) or 'continued' (on chronic ACEi/ARB and taken the morning of surgery). The co-primary outcomes were 'functional' AKI based upon changes in pre- to postoperative serum creatinine, and 'structural AKI', based upon peak postoperative levels of four urinary biomarkers of kidney injury. RESULTS: Across the three levels (none, held and continued) of ACEi/ARB exposure there was a graded increase in functional AKI, as defined by AKI stage 1 or worse; (31, 34 and 42%, P for trend 0.03) and by percentage change in serum creatinine from pre- to postoperative (25, 26 and 30%, P for trend 0.03). In contrast, there were no differences in structural AKI across the strata of ACEi/ARB exposure, as assessed by four structural AKI biomarkers (neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, interleukin-18 or liver-fatty acid-binding protein). CONCLUSIONS: Preoperative ACEi/ARB usage was associated with functional but not structural acute kidney injury. As AKI from ACEi/ARB in this setting is unclear, interventional studies testing different strategies of perioperative ACEi/ARB use are warranted.
Asunto(s)
Lesión Renal Aguda/inducido químicamente , Antagonistas de Receptores de Angiotensina/efectos adversos , Inhibidores de la Enzima Convertidora de Angiotensina/efectos adversos , Biomarcadores/orina , Procedimientos Quirúrgicos Cardíacos , Enfermedad de la Arteria Coronaria/cirugía , Lesión Renal Aguda/diagnóstico , Adulto , Anciano , Femenino , Humanos , Incidencia , Pruebas de Función Renal , Masculino , Persona de Mediana Edad , Cuidados Preoperatorios , Pronóstico , Estudios Prospectivos , Receptores de Angiotensina/química , Estados Unidos/epidemiologíaRESUMEN
This study investigated the role of angiotensin II receptor blocker in atrial remodeling in rats with atrial fibrillation (AF) induced by a myocardial infarction (MI). MIs were induced by a ligation of the left anterior descending coronary artery. Two days after, the rats in the losartan group were given losartan (10 mg/kg/day for 10 weeks). Ten weeks later, echocardiography and AF induction studies were conducted. Ejection fraction was significantly lower in the MI rats. Fibrosis analysis revealed much increased left atrial fibrosis in the MI group than sham (2.22 ± 0.66% vs 0.25 ± 0.08%, P = 0.001) and suppression in the losartan group (0.90 ± 0.27%, P 0.001) compared with the MI group. AF inducibility was higher in the MI group than sham (39.4 ± 43.0% vs 2.0 ± 6.3%, P = 0.005) and significantly lower in losartan group (12.0 ± 31.6%, P = 0.029) compared with the MI. The left atrial endothelial nitric oxide synthase (NOS) and sarco/endoplasmic reticulum Ca(2+)-ATPase levels were lower in the MI group and higher in the losartan group significantly. The atrial inducible NOS and sodium-calcium exchanger levels were higher in the MI and lower in the losartan group significantly. Losartan disrupts collagen fiber formation and prevents the alteration of the tissue eNOS and iNOS levels, which prevent subsequent AF induction.
Asunto(s)
Antagonistas de Receptores de Angiotensina/uso terapéutico , Fibrilación Atrial/prevención & control , Insuficiencia Cardíaca/etiología , Losartán/uso terapéutico , Infarto del Miocardio/complicaciones , Animales , Remodelación Atrial , Modelos Animales de Enfermedad , Fibrosis , Insuficiencia Cardíaca/diagnóstico por imagen , Inmunohistoquímica , Masculino , Infarto del Miocardio/diagnóstico por imagen , Óxido Nítrico Sintasa de Tipo II/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores de Angiotensina/química , Receptores de Angiotensina/metabolismo , ATPasas Transportadoras de Calcio del Retículo Sarcoplásmico/metabolismo , Intercambiador de Sodio-Calcio/metabolismo , UltrasonografíaRESUMEN
Earlier work showed that apoptosis of alveolar epithelial cells (AECs) in response to endogenous or xenobiotic factors is regulated by autocrine generation of angiotensin (ANG) II and its counterregulatory peptide ANG1-7. Mutations in surfactant protein C (SP-C) induce endoplasmic reticulum (ER) stress and apoptosis in AECs and cause lung fibrosis. This study tested the hypothesis that ER stress-induced apoptosis of AECs might also be regulated by the autocrine ANGII/ANG1-7 system of AECs. ER stress was induced in A549 cells or primary cultures of human AECs with the proteasome inhibitor MG132 or the SP-C BRICHOS domain mutant G100S. ER stress activated the ANGII-generating enzyme cathepsin D and simultaneously decreased the ANGII-degrading enzyme ACE-2, which normally generates the antiapoptotic peptide ANG1-7. TAPI-2, an inhibitor of ADAM17/TACE, significantly reduced both the activation of cathepsin D and the loss of ACE-2. Apoptosis of AECs induced by ER stress was measured by assays of mitochondrial function, JNK activation, caspase activation, and nuclear fragmentation. Apoptosis induced by either MG132 or the SP-C BRICHOS mutant G100S was significantly inhibited by the ANG receptor blocker saralasin and was completely abrogated by ANG1-7. Inhibition by ANG1-7 was blocked by the specific mas antagonist A779. These data show that ER stress-induced apoptosis is mediated by the autocrine ANGII/ANG1-7 system in human AECs and demonstrate effective blockade of SP-C mutation-induced apoptosis by ANG1-7. They also suggest that therapeutic strategies aimed at administering ANG1-7 or stimulating ACE-2 may hold potential for the management of ER stress-induced fibrotic lung disorders.
Asunto(s)
Angiotensina I/farmacología , Antihipertensivos/farmacología , Apoptosis/efectos de los fármacos , Estrés del Retículo Endoplásmico/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Fragmentos de Péptidos/farmacología , Alveolos Pulmonares/efectos de los fármacos , Angiotensina II/farmacología , Antagonistas de Receptores de Angiotensina/farmacología , Antineoplásicos/farmacología , Comunicación Autocrina , Células Cultivadas , Células Epiteliales/patología , Humanos , Leupeptinas/farmacología , Alveolos Pulmonares/patología , Proteína C Asociada a Surfactante Pulmonar/antagonistas & inhibidores , Proteína C Asociada a Surfactante Pulmonar/genética , Proteína C Asociada a Surfactante Pulmonar/metabolismo , Receptores de Angiotensina/química , Transducción de Señal/efectos de los fármacos , Vasoconstrictores/farmacologíaRESUMEN
Although the renin-angiotensin system (RAS) is already an old acquaintance, there are often exciting discoveries that improve our knowledge of it and open new therapeutic possibilities. Moreover, well-established drugs, such as angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), or beta-blockers, show that their mechanism of action may be the result of parallel pathways other than the ones initially established. A detailed analysis of the RAS can be carried out in part through the study of the enzymes, named angiotensinases, involved in its cascade, whose activity is a reflection of the functionality of their peptide substrates. The study of these enzymes offers the possibility of controlling the effects of angiotensins through various pharmacological manipulations. For example, angiotensinase inhibitors or activators are being used or have been proposed as antihypertensive agents. They have also been suggested as analgesic and antidepressant drugs or targets for drug development against different pathologies such as Alzheimer's disease, epilepsy or ischemia. On the other hand, the analysis of brain asymmetry has revealed surprising results about the laterality of central and peripheral components of the RAS. Such studies indicate that the neurovisceral integration, already proposed by Claude Bernard (1867) should also be analyzed from a bilateral perspective. In this review, the RAS and the role of various angiotensinases implicated in the cascade are revisited. Therapeutic strategies involving some components of the RAS with an unusual vision resulting from a bilateral perspective added to their study are discussed.
Asunto(s)
Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Angiotensinas/antagonistas & inhibidores , Antihipertensivos/farmacología , Sistema Renina-Angiotensina/efectos de los fármacos , Antagonistas de Receptores de Angiotensina/química , Antagonistas de Receptores de Angiotensina/farmacología , Antagonistas de Receptores de Angiotensina/uso terapéutico , Inhibidores de la Enzima Convertidora de Angiotensina/química , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Angiotensinas/metabolismo , Antihipertensivos/química , Antihipertensivos/uso terapéutico , Endopeptidasas/química , Endopeptidasas/metabolismo , Humanos , Hipertensión/tratamiento farmacológico , Inhibidores de Proteasas/química , Inhibidores de Proteasas/farmacología , Inhibidores de Proteasas/uso terapéutico , Receptores de Angiotensina/química , Receptores de Angiotensina/metabolismoRESUMEN
The biological functions of angiotensin (Ang) II are mediated by two Ang II receptors, designated type 1 receptor (AT1R) and type 2 receptor (AT2R). Most of the cardiovascular effects of Ang II are mediated by AT1R that is expressed widely in the body. The expression of AT1R is up-regulated in cardiovascular lesions, and is regulated by many endogenous bioactive substances and drugs. The AT2R is generally considered to antagonize the effects of AT1R, but its precise function remains enigmatic and controversial, particularly in humans. The expression of AT2R is low in normal adult animals, but AT2R expression is up-regulated in cardiovascular lesions. The dynamic regulation of AT1R and AT2R expression suggests an active involvement of Ang II receptors in the development of cardiovascular diseases such as atherosclerosis, heart failure, chronic kidney diseases and cerebrovascular diseases. Further clarification of gene regulatory mechanisms of Ang II receptors may identify potential targets for the development of novel therapeutics for cardiovascular diseases.
Asunto(s)
Regulación de la Expresión Génica , Receptores de Angiotensina/genética , Animales , Vasos Sanguíneos/química , Vasos Sanguíneos/metabolismo , Encéfalo/metabolismo , Química Encefálica , Enfermedades Cardiovasculares/tratamiento farmacológico , Humanos , Riñón/química , Riñón/metabolismo , Miocardio/química , Miocardio/metabolismo , Receptores de Angiotensina/análisis , Receptores de Angiotensina/químicaRESUMEN
The present study explored the hypothesis that a prolonged 8 weeks exposure to a high fructose intake suppresses adrenergic and angiotensin II (Ang II)-mediated vasoconstriction and is associated with a higher contribution of α1D-adrenoceptors. A total of thirty-two Sprague-Dawley rats received either 20 % fructose solution (FFR) or tap water (control, C) to drink ad libitum for 8 weeks. Metabolic and haemodynamic parameters were assessed weekly. The renal cortical vasoconstrictor responses to noradrenaline (NA), phenylephrine (PE), methoxamine (ME) and Ang II were determined in the presence and absence of BMY7378 (α1D-adrenoceptor antagonist). FFR had increased blood pressure, plasma levels of glucose, TAG and insulin. FFR expressed reduced renal vascular responses to adrenergic agonists and Ang II (NA: 50 %, PE: 50 %, ME, 65 %, Ang II: 54 %). Furthermore in the C group, the magnitude of the renal cortical vasoconstriction to all agonists was blunted in the presence of the low or high dose of BMY7378 (NA: 30 and 31 %, PE: 23 and 33 %, ME: 19 and 44 %, Ang II: 53 and 77 %), respectively, while in the FFR, vasoconstriction was enhanced to adrenergic agonists and reduced to Ang II (NA: 8 and 83 %, PE: 55 %, ME, 2 and 177 %, Ang II: 61 and 31 %). Chronic high fructose intake blunts vascular sensitivity to adrenergic agonists and Ang II. Moreover, blocking of the α1D-adrenoceptor subtype results in enhancement of renal vasoconstriction to adrenergic agonists, suggesting an inhibitory action of α1D-adrenoceptors in the FFR. α1D-Adrenoceptors buffer the AT1-receptor response in the renal vasculature of normal rats and fructose feeding suppressed this interaction.
Asunto(s)
Carbohidratos de la Dieta/efectos adversos , Fructosa/efectos adversos , Hiperinsulinismo/fisiopatología , Hipertensión/etiología , Riñón/irrigación sanguínea , Receptores Adrenérgicos alfa 1/metabolismo , Circulación Renal , Agonistas de Receptores Adrenérgicos alfa 1/farmacología , Antagonistas Adrenérgicos alfa/farmacología , Angiotensina II/metabolismo , Animales , Carbohidratos de la Dieta/administración & dosificación , Fructosa/administración & dosificación , Hemodinámica/efectos de los fármacos , Hiperglucemia/sangre , Hiperglucemia/etiología , Hiperinsulinismo/etiología , Hiperinsulinismo/metabolismo , Hipertensión/metabolismo , Hipertrigliceridemia/sangre , Hipertrigliceridemia/etiología , Riñón/efectos de los fármacos , Masculino , Norepinefrina/metabolismo , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Receptores Adrenérgicos alfa 1/química , Receptores de Angiotensina/química , Receptores de Angiotensina/metabolismo , Circulación Renal/efectos de los fármacos , Vasoconstrictores/farmacologíaRESUMEN
BACKGROUND: Nitric oxide (NO) deficiency contributes to chronic kidney disease (CKD) progression and hypertension. The ß-blocker, nebivolol (N), also enhances NO production, and we studied whether N attenuates CKD and hypertension caused by chronic NO synthase inhibition (CNOSI). METHODS: Male Sprague-Dawley rats on 6 weeks of CNOSI (L-NAME, 150 mg/L drinking water) received placebo (P), N (10 mg/kg/day), olmesartan (O, 2.5 mg/kg/day) or N + O. Blood pressure (BP) and urine protein and NOx (metabolites of NO) were monitored throughout. We measured glomerular sclerosis (GS), creatinine clearance (C(Cr)) and components of the NO and oxidant pathways in the renal cortex. RESULTS: BP increased >50 mmHg in P by weeks 4-6, but no change occurred in N, O or N + O. P rats developed proteinuria and GS and C(Cr) was â¼30% of normal. In N, O and N + O, all values remained normal. In renal cortex of P, p22phox and nitrotyrosine abundance as well as H(2)O(2) levels were higher and extracellular superoxide dismutase (EC SOD) was lower versus normal kidneys. N, O and N + O normalized p22phox, H(2)O(2) and EC SOD and increased Mn SOD above normal. The cortical neuronal NO synthase (nNOS) ß abundance increased in P and this was prevented by N, O and N + O. CONCLUSION: We suggest that the major benefit from both N and O is reduction in oxidative stress in the renal cortex, which may potentiate residual local NO. There was no additive benefit of N + O since each drug effectively prevented injury, but a combination may be beneficial where protection is incomplete with each drug. The increased nNOSß protein seen early in the course of the CKD may contribute to the evolving GS.
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Antagonistas de Receptores Adrenérgicos beta 1/uso terapéutico , Benzopiranos/uso terapéutico , Etanolaminas/uso terapéutico , Hipertensión/prevención & control , Fallo Renal Crónico/prevención & control , Óxido Nítrico Sintasa de Tipo II/antagonistas & inhibidores , Receptores de Angiotensina/química , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Animales , Western Blotting , Inhibidores Enzimáticos/farmacología , Peróxido de Hidrógeno/metabolismo , Hipertensión/enzimología , Hipertensión/etiología , Imidazoles/farmacología , Fallo Renal Crónico/enzimología , Fallo Renal Crónico/etiología , Masculino , NG-Nitroarginina Metil Éster/farmacología , Nebivolol , Óxido Nítrico/metabolismo , Ratas , Ratas Sprague-Dawley , Superóxido Dismutasa/metabolismo , Tetrazoles/farmacologíaRESUMEN
BACKGROUND: Previous studies have demonstrated that angiotensin Type I receptor blockade (ARB) reduces proteinuria, reverses glomerular injury and glomerulosclerosis in rat models of diabetic nephropathy and glomerulonephritis. However, the cellular and molecular mechanisms are unclear. To investigate the role of cells of the bone marrow (BM) in glomerular repair seen during ARB administration, we induced progressive glomerulosclerosis in enhanced green fluorescent protein BM chimeric rats by a single injection of anti-Thy 1.1 monoclonal antibody, followed by unilateral nephrectomy. METHODS: Cohorts of rats received valsartan or no treatment from Week 2 to Week 8 after induction of disease. Renal function, urinary protein excretion and histological changes were examined 8 weeks after anti-Thy-1.1 monoclonal antibody injection. RESULTS: Valsartan administration improved renal function, reduced severity of glomerulosclrosis and markedly reduced mortality. Valsartan administration promoted regeneration of the glomerular tuft, lowered proteinuria and resulted in enhanced vascular endothelial growth factor (VEGF) expression in the cortex and glomerular tuft. In addition, valsartan promoted increased recruitment of BM-derived cells (BMDCs) many of which expressed VEGF and likely contributed directly to glomerular repair. Nearly all BMDCs recruited to the glomerulus expressed the monocyte/macrophage marker CD68. CONCLUSIONS: In conclusion, the data shows that ARB by valsartan prevents glomerulosclerosis progression by enhancing glomerular capillary repair which is associated with the recruitment of VEGF producing 'reparative' monocytes and macrophages from the BM.
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Antagonistas de Receptores de Angiotensina/uso terapéutico , Médula Ósea/efectos de los fármacos , Glomeruloesclerosis Focal y Segmentaria/prevención & control , Receptores de Angiotensina/química , Tetrazoles/uso terapéutico , Valina/análogos & derivados , Factor A de Crecimiento Endotelial Vascular/metabolismo , Animales , Western Blotting , Médula Ósea/metabolismo , Médula Ósea/patología , Trasplante de Médula Ósea , Progresión de la Enfermedad , Femenino , Técnica del Anticuerpo Fluorescente , Glomeruloesclerosis Focal y Segmentaria/metabolismo , Glomeruloesclerosis Focal y Segmentaria/patología , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Técnicas para Inmunoenzimas , Isoanticuerpos/farmacología , Glomérulos Renales/citología , Glomérulos Renales/efectos de los fármacos , Glomérulos Renales/metabolismo , Masculino , Nefrectomía , Ratas , Ratas Sprague-Dawley , Ratas Transgénicas , Antígenos Thy-1/inmunología , Valina/uso terapéutico , ValsartánRESUMEN
Intercalated cells in the collecting duct system express V-type H(+)-ATPases which participate in acid extrusion, bicarbonate secretion, and chloride absorption depending on the specific subtype. The activity of H(+)-ATPases is regulated by acid-base status and several hormones, including angiotensin II and aldosterone. Angiotensin II stimulates chloride absorption mediated by pendrin in type B intercalated cells and this process is energized by the activity of H(+)-ATPases. Moreover, angiotensin II stimulates bicarbonate secretion by the connecting tubule (CNT) and early cortical collecting duct (CCD). In the present study we examined the effect of angiotensin II (10 nM) on H(+)-ATPase activity and localization in isolated mouse connecting tubules and cortical collecting ducts. Angiotensin II stimulated Na(+)-independent intracellular pH recovery about 2-3 fold, and this was abolished by the specific H(+)-ATPase inhibitor concanamycin. The effect of angiotensin II was mediated through type 1 angiotensin II receptors (AT(1)-receptors) because it could be blocked by saralasin. Stimulation of H(+)-ATPase activity required an intact microtubular network--it was completely inhibited by colchicine. Immunocytochemistry of isolated CNT/CCDs incubated in vitro with angiotensin II suggests enhanced membrane associated staining of H(+)-ATPases in pendrin expressing intercalated cells. In summary, angiotensin II stimulates H(+)-ATPases in CNT/CCD intercalated cells, and may contribute to the regulation of chloride absorption and bicarbonate secretion in this nephron segment.
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Angiotensina II/farmacología , Corteza Renal/enzimología , Túbulos Renales Colectores/enzimología , ATPasas de Translocación de Protón Vacuolares/metabolismo , Animales , Proteínas de Transporte de Anión/metabolismo , Bicarbonatos/metabolismo , Membrana Celular/metabolismo , Cloruros/metabolismo , Colchicina/farmacología , Concentración de Iones de Hidrógeno , Inmunohistoquímica , Corteza Renal/citología , Corteza Renal/patología , Túbulos Renales Colectores/citología , Túbulos Renales Colectores/patología , Macrólidos/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Receptores de Angiotensina/química , Receptores de Angiotensina/metabolismo , Saralasina/farmacología , Sodio/metabolismo , Transportadores de Sulfato , ATPasas de Translocación de Protón Vacuolares/análisis , ATPasas de Translocación de Protón Vacuolares/antagonistas & inhibidoresRESUMEN
Angiotensin IV (AngIV; Val(1)-Tyr(2)-Ile(3)-His(4)-Pro(5)-Phe(6))-related peptides have emerged as potential antidementia agents. However, their development as practical therapeutic agents has been impeded by a combination of metabolic instability, poor blood-brain barrier permeability, and an incomplete understanding of their mechanism of action. This study establishes the core structure contained within norleucine(1)-angiotensin IV (Nle(1)-AngIV) that is required for its procognitive activity. Results indicated that Nle(1)-AngIV-derived peptides as small as tetra- and tripeptides are capable of reversing scopolamine-induced deficits in Morris water maze performance. This identification of the active core structure contained within Nle(1)-AngIV represents an initial step in the development of AngIV-based procognitive drugs. The second objective of the study was to clarify the general mechanism of action of these peptides by assessing their ability to affect changes in dendritic spines. A correlation was observed between a peptide's procognitive activity and its capacity to increase spine numbers and enlarge spine head size. These data suggest that the procognitive activity of these molecules is attributable to their ability to augment synaptic connectivity.
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Hipocampo/crecimiento & desarrollo , Aprendizaje por Laberinto/efectos de los fármacos , Memoria/efectos de los fármacos , Receptores de Angiotensina/química , Sinapsis/efectos de los fármacos , Animales , Conducta Animal/efectos de los fármacos , Recuento de Células , Células Cultivadas , Cognición/efectos de los fármacos , Dendritas/efectos de los fármacos , Dendritas/ultraestructura , Espinas Dendríticas/efectos de los fármacos , Espinas Dendríticas/ultraestructura , Relación Dosis-Respuesta a Droga , Hipocampo/efectos de los fármacos , Inmunohistoquímica , Masculino , Antagonistas Muscarínicos/farmacología , Técnicas de Placa-Clamp , Fragmentos de Péptidos/farmacología , Ratas , Ratas Sprague-Dawley , Escopolamina/antagonistas & inhibidores , Escopolamina/farmacología , Relación Estructura-Actividad , TransfecciónRESUMEN
BACKGROUND: Renoprotective actions of angiotensin receptor blockers are not well established in normotensive, low-grade proteinuric glomerular diseases. We examined the effect of low-dose telmisartan (LT) and high-dose telmisartan (HT) versus conventional antihypertensive therapy in the rat anti-Thy1.1 model of glomerulonephritis. METHODS: Rats were randomized on Day 4 after disease induction to no treatment (CT, control), LT or HT or hydrochlorothiazide + hydralazine (HCT + H). RESULTS: All rats remained normotensive: HT and HCT + H reduced blood pressure by 15-20%. LT, HT and HCT + H reduced glomerular endothelial cell proliferation and glomerular and interstitial matrix deposition on Day 14. Only HT reduced podocyte damage and tubular cell dedifferentiation on Day 9 and mesangial cell activation on Day 14. By gene expression analysis arrays, we identified discs-large homolog 1 and angiopoietin-like 4 as potential mediators of the HT effects. In addition, we identified several pathways possibly related to the pleiotropic effects of HT, including growth factor signalling, mammalian target of rapamycin signalling, protein ubiquitination, the Wnt-beta catenin pathway and hypoxia signaling. CONCLUSIONS: In summary, treatment with HT, initiated after the induction of disease, ameliorates glomerular and tubulointerstitial damage. We provide the first comprehensive insight into the mechanisms underlying the renoprotective effect of high-dose angiotensin II receptor blockers (ARBs). Our study lays the basis for future investigations on novel pathways affected by ARBs in renal disease.
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Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Bencimidazoles/farmacología , Benzoatos/farmacología , Glomerulonefritis/tratamiento farmacológico , Glomerulonefritis/patología , Células Mesangiales/citología , Células Mesangiales/efectos de los fármacos , Receptores de Angiotensina/química , Animales , Biomarcadores/metabolismo , Proliferación Celular , Perfilación de la Expresión Génica , Glomerulonefritis/metabolismo , Técnicas para Inmunoenzimas , Glomérulos Renales/citología , Glomérulos Renales/efectos de los fármacos , Masculino , Análisis de Secuencia por Matrices de Oligonucleótidos , ARN Mensajero/genética , Ratas , Ratas Endogámicas Lew , Ratas Sprague-Dawley , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de Angiotensina/metabolismo , TelmisartánRESUMEN
A series of o-, m- and p-benzyl tetrazole derivatives 11a-c has been designed, synthesized and evaluated as potential Angiotensin II AT1 receptor antagonists, based on urocanic acid. Compound 11b with tetrazole moiety at the m-position showed moderate, however, higher activity compared to the o- and p-counterpart analogues. Molecular modelling techniques were performed in order to extract their putative bioactive conformations and explore their binding modes.