RESUMEN
T cell immunoglobulin domain and mucin domain-containing molecule 3 (Tim-3) is a newly discovered immunomodulatory, which plays an important role in immunity regulation. Recent evidence suggests that Tim-3 is differentially regulated in a variety of tumors and has a potential as a therapeutic target. The aim of this study was to investigate the effect of Tim-3 on the development of prostate cancer (PCa). Tim-3 expressing on peripheral CD4+ T and CD8+ T cells was analyzed by flow cytometry. The relationships between Tim-3 expression and clinicopathological features were analyzed. Immunohistochemical expression of Tim-3 was examined in our large numbers of paraffin-fixed prostate tissues. Flow cytometry revealed that expression of Tim-3 was significantly increased on both CD4+ and CD8+ T cells in PCa patients than that in benign prostate hyperplasia (BPH) patients. Also, the level of Tim-3 on CD4+ T cells was positively correlated with CD8+ T cells in patients. Further analyses revealed that the levels of Tim-3 on CD4+ T cells and CD8+ T cells exhibited different expression patterns in terms of localization depending on pathological category of PCa and metastasis. Immunohistochemical analysis revealed that positive staining of Tim-3 in PCa but little or no staining of Tim-3 was observed in BPH epithelium. Tim-3 may affect the development and progression of PCa, which may provide knowledge for using Tim-3 as a novel therapy for effective PCa management.
Asunto(s)
Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos/metabolismo , Proteínas de la Membrana/metabolismo , Hiperplasia Prostática/metabolismo , Neoplasias de la Próstata/metabolismo , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/patología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/patología , Progresión de la Enfermedad , Citometría de Flujo , Estudios de Seguimiento , Receptor 2 Celular del Virus de la Hepatitis A , Humanos , Técnicas para Inmunoenzimas , Masculino , Persona de Mediana Edad , Clasificación del Tumor , Estadificación de Neoplasias , Pronóstico , Hiperplasia Prostática/inmunología , Hiperplasia Prostática/patología , Neoplasias de la Próstata/inmunología , Neoplasias de la Próstata/patologíaRESUMEN
Blood pressure (BP) increases after menopause. However, the mechanisms responsible have not been elucidated. In this study we tested the hypothesis that 20-hydroxyeicosatetraenoic acids (20-HETE), produced by cytochrome P-450 (CYP450) ω-hydroxylase, contributes to the hypertension in a model of postmenopausal hypertension, aged female spontaneously hypertensive rats (PMR). 1-Aminobenzotriazole, a nonselective inhibitor of arachidonic acid metabolism, for 7 days, reduced BP in PMR but had no effect in young females. Acute intravenous infusion of HET-0016, a specific inhibitor of 20-HETE, over 3 h, also reduced BP in PMR. CYP4A isoform mRNA expression showed no difference in renal CYP4A1 or CYP4A3 but increases in CYP4A2 and decreases in CYP4A8. CYP4A protein expression was decreased in kidney of PMR compared with young females. Endogenous 20-HETE was significantly higher in cerebral vessels of PMR than young females (YF) but was significantly lower in renal vessels of PMR. Omega-hydroxylase activity in cerebral vessels was also higher in PMR but was similar in kidney vessels in both groups. In renal microsomal preparations, endogenous 20-HETE was not different in PMR and young females, but ω-hydroxylase activity was significantly lower in PMR than YF. The data with blockers suggest that 20-HETE contributes to postmenopausal hypertension in SHR. The data also suggest that cerebral production of 20-HETE may be increased and renal tubular production may be decreased in PMR, thus both contributing to their elevated BP.
Asunto(s)
Envejecimiento/fisiología , Ácidos Hidroxieicosatetraenoicos/fisiología , Hipertensión/fisiopatología , Posmenopausia/fisiología , Animales , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Citocromo P-450 CYP4A/metabolismo , Modelos Animales de Enfermedad , Femenino , Riñón/metabolismo , Ratas , Ratas Endogámicas SHR , Triazoles/farmacologíaRESUMEN
Angiotensin-(1-7) [ANG-(1-7)], one of the bioactive peptides produced in the renin-angiotensin system, plays a pivotal role in cardiovascular physiology by providing a counterbalance to the function of ANG II. Recently, it has been considered as a potential candidate for therapeutic use in the treatment of various types of cardiovascular diseases. The aim of the present study is to explain the modulatory role of ANG-(1-7) in atrial natriuretic peptide (ANP) secretion and investigate the functional relationship between two peptides to induce cardiovascular effects using isolated perfused beating rat atria and a cardiac hypertrophied rat model. ANG-(1-7) (0.01, 0.1, and 1 muM) increased ANP secretion and ANP concentration in a dose-dependent manner at high atrial pacing (6.0 Hz) with increased cGMP production. However, at low atrial pacing (1.2 Hz), ANG-(1-7) did not cause changes in atrial parameters. Pretreatment with an antagonist of the Mas receptor or with inhibitors of phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), or nitric oxide synthase blocked the augmentation of high atrial pacing-induced ANP secretion by ANG-(1-7). A similar result was observed with the inhibition of the Na(+)/H(+) exchanger-1 and Ca(2+)/calmodulin-dependent kinase II (CaMKII). ANG-(1-7) did not show basal intracellular Ca(2+) signaling in quiescent atrial myocytes. In an in vivo study using an isoproterenol-induced cardiac hypertrophy animal model, an acute infusion of ANG-(1-7) increased the plasma concentration of ANP by twofold without changes in blood pressure and heart rate. A chronic administration of ANG-(1-7) increased the plasma ANP level and attenuated isoproterenol-induced cardiac hypertrophy. The antihypertrophic effect was abrogated by a cotreatment with the natriuretic peptide receptor-A antagonist. These results suggest that 1) ANG-(1-7) increased ANP secretion at high atrial pacing via the Mas/PI3K/Akt pathway and the activation of Na(+)/H(+) exchanger-1 and CaMKII and 2) ANG-(1-7) decreased cardiac hypertrophy which might be mediated by ANP.
Asunto(s)
Angiotensina I/farmacología , Factor Natriurético Atrial/metabolismo , Estimulación Cardíaca Artificial , Fragmentos de Péptidos/farmacología , Fosfatidilinositol 3-Quinasas/fisiología , Proteínas Proto-Oncogénicas c-akt/fisiología , Proteínas Proto-Oncogénicas/fisiología , Receptores Acoplados a Proteínas G/fisiología , Transducción de Señal/efectos de los fármacos , Intercambiadores de Sodio-Hidrógeno/metabolismo , Animales , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Cardiotónicos/farmacología , GMP Cíclico/metabolismo , Técnicas In Vitro , Isoproterenol/farmacología , Masculino , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Proto-Oncogenes Mas , Radioinmunoensayo , Ratas , Ratas Sprague-Dawley , Receptores del Factor Natriurético Atrial/antagonistas & inhibidores , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Intercambiadores de Sodio-Hidrógeno/efectos de los fármacosRESUMEN
Leptin is a circulating adipocyte-derived hormone that influences blood pressure (BP) and metabolism. This study was designed to define the possible role of leptin in regulation of the atrial natriuretic peptide (ANP) system using acute and chronic experiments. Intravenous infusion of rat leptin (250 microg/kg injection plus 2 microg.kg(-1).min(-1) for 20 min) into Sprague-Dawley rats increased BP by 25 mmHg and decreased plasma level of ANP from 80.3 +/- 3.45 to 51.8 +/- 3.3 pg/ml. Reserpinization attenuated the rise in BP, but not the reduction of plasma ANP during leptin infusion. N(omega)-nitro-l-arginine methyl ester prevented the effects of leptin on the reduction of ANP level. In hyperleptinemic rats that received adenovirus containing rat leptin cDNA (AdCMV-leptin), BP increased during first 2 days and then recovered to control value. Plasma concentration of ANP and expression of ANP mRNA, but not of atrial ANP, in hyperleptinemic rats were lower than in the control groups on the first and second week after administration of AdCMV-leptin. These effects were not observed by the pretreatment with N(omega)-nitro-l-arginine methyl ester. No differences in renal function and ANP receptor density in the kidney were found between hyperleptinemic and control rats. Basal ANP secretion and isoproterenol-induced suppression of ANP secretion from isolated, perfused atria of hyperleptinemic rats were not different from those of other control groups. These data suggest that leptin inhibits ANP secretion indirectly through nitric oxide without changing basal or isoproterenol-induced ANP secretion.
Asunto(s)
Factor Natriurético Atrial/sangre , Leptina/farmacología , Óxido Nítrico/fisiología , Animales , Factor Natriurético Atrial/efectos de los fármacos , Factor Natriurético Atrial/genética , Factor Natriurético Atrial/metabolismo , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Arterias Carótidas/efectos de los fármacos , Arterias Carótidas/fisiología , Hipertensión/sangre , Hipertensión/inducido químicamente , Isoproterenol/farmacología , Venas Yugulares/efectos de los fármacos , Venas Yugulares/fisiología , Riñón/efectos de los fármacos , Riñón/fisiología , Leptina/sangre , Masculino , NG-Nitroarginina Metil Éster/farmacología , ARN Mensajero/sangre , ARN Mensajero/genética , Ratas , Ratas Sprague-Dawley , Reserpina/farmacologíaRESUMEN
Cold exposure induces hypertension and cardiac hypertrophy via sympathetic activation. The sympathetic nervous system is fundamentally important for the regulation of cardiac atrial natriuretic peptide (ANP) secretion. The present study aimed to define changes in ANP level with renal functions during cold exposure of rats. We also measured the direct effects of adrenergic stimulation on ANP secretion in cold-induced hypertensive rat atria. Sustained elevation of blood pressure and tachycardia were observed by 2-wk cold exposure. Cold exposure increased urine volume, UNaV, UKV and positive water balance. Atrial ANP content, its mRNA level, and plasma ANP concentration increased. Plasma norepinephrine level was increased but both alpha(1A)- and beta(1)-adrenoceptor (AR) mRNA levels in atrium were decreased. In isolated perfused atria from cold-exposed rats, basal ANP secretion increased and pulse pressure decreased. Phenylephrine (alpha(1)-AR agonist)-induced stimulation of ANP secretion, and isoproterenol (beta-AR agonist)-induced suppression of ANP secretion were significantly attenuated. These results suggest that an increased plasma and atrial ANP level by cold exposure may be a compensatory response to changes in hemodynamics and body fluid balance. The phenylephrine- and isoproterenol-induced attenuation of ANP secretion in cold-exposed rat atria may be due to the downregulation of alpha(1A)- and beta(1)-adrenoceptors mRNA levels.
Asunto(s)
Factor Natriurético Atrial/metabolismo , Frío , Hipertensión/metabolismo , Receptores Adrenérgicos/metabolismo , Agonistas alfa-Adrenérgicos/farmacología , Agonistas Adrenérgicos beta/farmacología , Animales , Antihipertensivos/farmacología , Factor Natriurético Atrial/sangre , Presión Sanguínea/efectos de los fármacos , AMP Cíclico/metabolismo , Relación Dosis-Respuesta a Droga , Guanabenzo/farmacología , Atrios Cardíacos/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Isoproterenol/farmacología , Masculino , Fenilefrina/farmacología , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores Adrenérgicos/efectos de los fármacos , Sistema Nervioso Simpático/metabolismo , Factores de TiempoRESUMEN
Adenosine is a potent mediator of myocardial protection against hypertrophy via A(1) or A(3) receptors that may be partly related to atrial natriuretic peptide (ANP) release. However, little is known about the possible involvement of the A(3) receptor on ANP release. We studied the effects of the A(3) receptor on atrial functions and its modification in hypertrophied atria. A selective A(3) receptor agonist, 2-chloro-N(6)-(3-iodobenzyl) adenosine-5'-N-methyluronamide (2-CI-IB-MECA), was perfused into isolated, beating rat atria with and without receptor modifiers. 2-CI-IB-MECA dose-dependently increased the ANP secretion, which was blocked by the A(3) receptor antagonist, but the increased atrial contractility and decreased cAMP levels induced by 30muM 2-CI-IB-MECA were not affected. The 100muM 2-(1-hexylnyl)-N-methyladenosine (HEMADO) and N(6)-(3-iodobenzyl) adenosine-5'-N-methyluronamide (IB-MECA), A(3) receptor agonist, also stimulated the ANP secretion without positive inotropy. The potency for the stimulation of ANP secretion was 2-CI-IB-MECA>>IB-MECA=HEMADO. The inhibition of the ryanodine receptor or calcium/calmodulin-dependent kinase II (CaMKII) attenuated 2-CI-IB-MECA-induced ANP release, positive inotropy, and translocation of extracellular fluid. However, the inhibition of L-type Ca(2+) channels, sarcoplasmic reticulum Ca(2+)-reuptake, phospholipase C or inositol 1,4,5-triphosphate receptors did not affect these parameters. 2-CI-IB-MECA decreased cAMP level, which was blocked only with an inhibitor of CaMKII or adenylyl cyclase. These results suggest that 2-CI-IB-MECA increases the ANP secretion mainly via A(3) receptor activation and positive inotropy by intracellular Ca(2+) regulation via the ryanodine receptor and CaMKII.
Asunto(s)
Adenosina/análogos & derivados , Factor Natriurético Atrial/metabolismo , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Receptor de Adenosina A3/metabolismo , Adenosina/farmacología , Agonistas del Receptor de Adenosina A3 , Animales , Calcio/metabolismo , Canales de Calcio Tipo L/fisiología , AMP Cíclico/metabolismo , Líquido Extracelular/metabolismo , Atrios Cardíacos/metabolismo , Atrios Cardíacos/fisiopatología , Técnicas In Vitro , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Masculino , Contracción Miocárdica , Ratas , Ratas Sprague-Dawley , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Fosfolipasas de Tipo C/metabolismoRESUMEN
Sympathetic nervous system and atrial natriuretic peptide (ANP) system play fundamental roles in the regulation of cardiovascular functions. Overactivity of sympathetic nervous system can lead into cardiovascular diseases such as heart failure and hypertension. The present study aimed to define which adrenergic receptors (ARs) affect atrial contractility and ANP release and to determine their modification in renal hypertensive rat atria. An alpha(1)-AR agonist, cirazoline increased ANP release with positive inotropism. These alpha(1)-AR agonist-mediated responses were attenuated by the alpha(1A)-AR antagonist, but not by the alpha(1B)- or alpha(1D)-AR antagonist. An alpha(2)-AR agonist, guanabenz and clonidine increased ANP release with negative inotropism and decreased cAMP level. The order of potency for the increased ANP release was cirazoline>>phenylephrine=guanabenz>>clonidine. In contrast, a beta-AR agonist, isoproterenol decreased ANP release with positive inotropism and these responses were blocked by the beta(1)-AR antagonist but not by the beta(2)-AR antagonist. The increased cAMP level by isoproterenol was suppressed by pretreatment with both beta(1)- and beta(2)-AR antagonists. In renal hypertensive rat atria, the effects of isoproterenol on atrial contractility, ANP release, and cAMP level were attenuated whereas the effect of cirazoline on ANP release was unaltered. Atrial beta(1)-AR mRNA level but not alpha(1A)-AR mRNA level was decreased in renal hypertensive rats. These findings suggest that alpha(1A)- and beta(1)-AR oppositely regulate atrial ANP release and that atrial beta(1)-AR expression/function is impaired in renal hypertensive rats.
Asunto(s)
Factor Natriurético Atrial/metabolismo , Atrios Cardíacos/efectos de los fármacos , Hipertensión Renal/fisiopatología , Receptores Adrenérgicos/efectos de los fármacos , Agonistas alfa-Adrenérgicos/farmacología , Agonistas Adrenérgicos beta/farmacología , Animales , Clonidina/farmacología , AMP Cíclico/metabolismo , Relación Dosis-Respuesta a Droga , Guanabenzo/farmacología , Atrios Cardíacos/metabolismo , Imidazoles/farmacología , Isoproterenol/farmacología , Masculino , Fenilefrina/farmacología , ARN Mensajero/metabolismo , Ensayo de Unión Radioligante , Ratas , Ratas Sprague-Dawley , Factores de TiempoRESUMEN
Cardiac hypertrophy, an adaptive process to an increased hemodynamic overload, includes not only an increase in cell size but also qualitative changes in constituent proteins. Although swelling-activated chloride channels (I(Cl,swell)) chronically activate in hypertrophied atrial myocytes, the role of I(Cl,swell) in regulation of atrial natriuretic peptide (ANP) release is poorly understood. We investigated the effects of I(Cl,swell) on ANP release and contractility and its modification in hypertrophied rat atria. To stimulate I(Cl,swell), hypoosmotic HEPES buffered solution (0.8T, 0.7T and 0.6T) was perfused into isolated perfused beating atria. The hypoosmotic HEPES buffered solution increased ANP release as compared to isoosmotic buffered solution (1T) in an osmolarity-reduction dependent manner. Atrial contractility and extracellular fluid translocation did not change. Exposure to hypoosmotic buffer (0.8T) containing low chloride (8mM), tamoxifen or diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) significantly attenuated hypoosmolarity-induced ANP release. The pretreatment with genistein, okdaic acid, U73122, GF109203x, and staurosporine attenuated hypoosmolarity-induced ANP release whereas orthovanadate augmented it significantly. In hypertrophied atria from renal hypertensive rats, hypoosmolarity-induced ANP release was markedly attenuated and DIDS-induced decrease in ANP release and negative inotropy were augmented as compared to sham-operated rat atria. Therefore, we suggest that I(Cl,swell) may partly participate hypoosmolarity-induced ANP release through protein tyrosine kinase and phospholipase C-protein kinase C pathway. The modification of responses of ANP release to hypoosmolarity and DIDS in hypertrophied atria may relate to changes in I(Cl,swell) activity by persistent high blood pressure.
Asunto(s)
Factor Natriurético Atrial/metabolismo , Canales de Cloruro/fisiología , Atrios Cardíacos/metabolismo , Hipertensión Renal/fisiopatología , Presión Osmótica , Ácido 4,4'-Diisotiocianostilbeno-2,2'-Disulfónico/farmacología , Animales , Cardiomegalia/fisiopatología , Estrenos/farmacología , Líquido Extracelular/fisiología , Genisteína/farmacología , Atrios Cardíacos/efectos de los fármacos , Indoles/farmacología , Maleimidas/farmacología , Ácido Ocadaico/farmacología , Pirrolidinonas/farmacología , Ratas , Ratas Sprague-Dawley , Estaurosporina/farmacología , Tamoxifeno/farmacología , Vanadatos/farmacologíaRESUMEN
This study was aimed to define roles of stretch-activated ion channels (SACs), especially Cl(-) channels, in regulation of atrial natriuretic peptide (ANP) secretion using isolated perfused beating atria. The volume load was achieved by elevating height of outflow catheter connected to isolated rat atria and the pressure load was achieved by decreasing diameter of outflow catheter. Both methods increased atrial contractility similarly although volume load was different (736microl for volume load vs. 129microl for pressure load). Atrial stretch by volume load markedly increased ECF translocation and ANP secretion but the pressure load slightly increased. The ANP secretion was positively correlated to workload generated by volume or pressure load. Treatment of atria with gadolinium, a blocker for SACs, attenuated the ECF translocation and the ANP secretion induced by volume load. A blocker for Ca2+-activated Cl(-) channel, niflumic acid (NFA), accentuated the ANP secretion induced by volume load whereas a blocker for swelling-activated Cl(-) channel, diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), attenuated the ANP secretion. The ANP secretion of hypertrophied atria by volume load was markedly reduced and the augmented effect of NFA on volume load-induced ANP secretion was not observed. These results indicate that Cl(-) channels may differently regulate stretch-activated ANP secretion.
Asunto(s)
Factor Natriurético Atrial/metabolismo , Canales de Cloruro/metabolismo , Animales , Canales de Cloruro/antagonistas & inhibidores , Gadolinio/farmacología , Atrios Cardíacos/metabolismo , Masculino , Contracción Miocárdica , Ácido Niflúmico/farmacología , RatasRESUMEN
This study aimed to determine the effects of levosimendan, a calcium sensitizer, on atrial contractility and atrial natriuretic peptide (ANP) secretion and its modification in hypertrophied atria. Isolated perfused beating rat atria were used from control and isoproterenol-treated rats. Levosimendan and its metabolite OR-1896 caused a positive inotropic effect and suppressed ANP secretion in rat atria. Similar to levosimendan, the selective phosphodiesterase 3 (PDE3) or PDE4 inhibitor also suppressed ANP secretion. Suppression of ANP secretion by 1⯵M levosimendan was abolished by PDE3 inhibitor, but reversed by PDE4 inhibitor. Levosimendan-induced suppression of ANP secretion was potentiated by KATP channel blocker, but blocked by KATP channel opener. Levosimendan alone did not significantly change cyclic adenosine monophosphate (cAMP) efflux in the perfusate; however, levosimendan combined with PDE4 inhibitor markedly increased this efflux. The stimulation of ANP secretion induced by levosimendan combined with PDE4 inhibitor was blocked by the protein kinase A (PKA) inhibitor. In isoproterenol-treated atria, levosimendan augmented the positive inotropic effect and ANP secretion in response to an increased extracellular calcium concentration ([Ca+]o). These results suggests that levosimendan suppresses ANP secretion by both inhibiting PDE3 and opening KATP channels and that levosimendan combined with PDE4 inhibitor stimulates ANP secretion by activating the cAMP-PKA pathway. Modification of the effects of levosimendan on [Ca+]o-induced positive inotropic effects and ANP secretion in isoproterenol-treated rat atria might be related to a disturbance in calcium metabolism.
Asunto(s)
Factor Natriurético Atrial/metabolismo , Atrios Cardíacos/metabolismo , Atrios Cardíacos/patología , Hidrazonas/farmacología , Piridazinas/farmacología , Animales , Función Atrial/efectos de los fármacos , Presión Atrial/efectos de los fármacos , Calcio/metabolismo , Espacio Extracelular/efectos de los fármacos , Espacio Extracelular/metabolismo , Atrios Cardíacos/efectos de los fármacos , Hemodinámica/efectos de los fármacos , Hipertrofia/metabolismo , Hipertrofia/patología , Hipertrofia/fisiopatología , Masculino , Ratas , Ratas Sprague-Dawley , SimendánRESUMEN
Diadenosine polyphosphates (APnAs) are endogenous compounds and exert diverse cardiovascular functions. However, the effects of APnAs on atrial ANP release and contractility have not been studied. In this study, the effects of diadenosine tetraphosphate (AP4A) on atrial ANP release and contractility, and their mechanisms were studied using isolated perfused rat atria. Treatment of atria with AP4A resulted in decreases in atrial contractility and extracellular fluid (ECF) translocation whereas ANP secretion and cAMP levels in perfusate were increased in a dose-dependent manner. These effects of AP4A were attenuated by A(1) receptor antagonist but not by A(2A) or A(3) receptor antagonist. Other purinoceptor antagonists also did not show any effects on AP4A-induced ANF release and contractility. The increment of ANP release and negative inotropy induced by AP4A was similar to those induced by AP3A, AP5A, and AP6A. Protein kinase A inhibitors accentuated AP4A-induced ANP secretion. In contrast, an inhibitor of phospholipase C, protein kinase C or sarcolemma K(ATP) channel completely blocked AP4A-induced ANP secretion. However, an inhibitor of adenylyl cyclase or mitochondria K(ATP) channel had no significant modification of AP4A effects. These results suggest that AP4A regulates atrial inotropy and ANP release mainly through A(1) receptor signaling involving phospholipase C-protein kinase C and sarcolemmal K(ATP) channel and that protein kinase A negatively modulates the effects of AP4A.
Asunto(s)
Factor Natriurético Atrial/metabolismo , Fosfatos de Dinucleósidos/farmacología , Canales de Potasio/metabolismo , Proteína Quinasa C/metabolismo , Receptor de Adenosina A1/metabolismo , Animales , Atrios Cardíacos/metabolismo , Masculino , Contracción Miocárdica/fisiología , Isoformas de Proteínas/metabolismo , Ratas , Ratas Sprague-Dawley , Transducción de SeñalRESUMEN
The aim of present study was to define the effects of insulin on atrial dynamics and ANP release and its modification in diabetic rats. An isolated perfused beating atrial model was used from control and diabetic rats. Insulin was perfused with and without an inhibitor for tyrosine kinase or phosphatidylinositol 3-kinase (PI 3-kinase). Insulin increased the release of ANP and decreased atrial contractility in a dose-dependent manner. During the perfusion of 10(-10)M insulin, the release of ANP abruptly increased within 8min by approximately 40% and then decreased with time despite of continuous perfusion. In terms of increasing the dose of insulin, the time to reach the peak effect became faster and the slope to decrease became slower. In contrast, atrial contractility was gradually decreased with time. These effects were independent upon extracellular glucose. Genistein (10(-5)M) or lavendustin C (10(-5)M), a tyrosine kinase inhibitor, attenuated the release of ANP stimulated by insulin (10(-8)M). Wortmannin (10(-7)M) or LY294002 (10(-5)M), a PI 3-kinase inhibitor, also attenuated insulin-stimulated ANP release. However, both inhibitors for PI 3-kinase and tyrosine kinase did not cause any significant effects on negative inotropism by insulin. Insulin-stimulated ANP release was augmented in streptozotocin-treated rat atria. The density of insulin receptor markedly increased in diabetic hearts. These results suggest that insulin stimulates the release of ANP through PI 3-kinase and tyrosine kinase, and augmentation of insulin-stimulated ANP release in diabetic rat atria may be partly due to an upregulation of insulin receptor.
Asunto(s)
Función del Atrio Izquierdo , Factor Natriurético Atrial/biosíntesis , Diabetes Mellitus/metabolismo , Insulina/farmacología , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Animales , Masculino , Ratas , Ratas Sprague-Dawley , Transducción de SeñalRESUMEN
Angiotensin-(1-5) [Ang-(1-5)], which is a metabolite of Angiotensin-(1-7) [Ang-(1-7)] catalyzed by angiotensin-converting enzyme (ACE), is a pentapeptide of the renin-angiotensin system (RAS). It has been reported that Ang-(1-7) and Ang-(1-9) stimulate the secretion of atrial natriuretic peptide (ANP) via Mas receptor (Mas R) and Ang II type 2 receptor (AT2R), respectively. However, it still remains unknown whether Ang-(1-5) has a similar function to Ang-(1-7). We investigated the effect of Ang-(1-5) on ANP secretion and to define its signaling pathway using isolated perfused beating rat atria. Ang-(1-5) (0.3, 3, 10µM) stimulated high pacing frequency-induced ANP secretion in a dose-dependent manner. Ang-(1-5)-induced ANP secretion (3µM) was attenuated by the pretreatment with an antagonist of Mas R (A-779) but not by an antagonist of AT1R (losartan) or AT2R (PD123,319). An inhibitor for phosphatidylinositol 3-kinase (PI3K; wortmannin), protein kinase B (Akt; API-2), or nitric oxide synthase (NOS; L-NAME) also attenuated the augmentation of ANP secretion induced by Ang-(1-5). Ang-(1-5)-induced ANP secretion was markedly attenuated in isoproterenol-treated hypertrophied atria. The secretagogue effect of Ang-(1-5) on ANP secretion was similar to those induced by Ang-(1-9) and Ang-(1-7). These results suggest that Ang-(1-5) is an active mediator of renin-angiotensin system to stimulate ANP secretion via Mas R and PI3K-Akt-NOS pathway.
Asunto(s)
Angiotensina II/fisiología , Factor Natriurético Atrial/metabolismo , Fragmentos de Péptidos/fisiología , Proteínas Proto-Oncogénicas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Angiotensina II/farmacología , Animales , Presión Sanguínea , Atrios Cardíacos/efectos de los fármacos , Masculino , Fragmentos de Péptidos/farmacología , Proto-Oncogenes Mas , Ratas Sprague-Dawley , Receptor de Angiotensina Tipo 1/metabolismo , Receptor de Angiotensina Tipo 2/metabolismo , Sistema Renina-Angiotensina , Transducción de SeñalRESUMEN
The endothelins (ET) peptide family consists of ET-1, ET-2, ET-3, and sarafotoxin (s6C, a snake venom) and their actions appears to be different among isoforms. The aim of this study was to compare the secretagogue effect of ET-1 on atrial natriuretic peptide (ANP) secretion with ET-3 and evaluate its physiological meaning. Isolated nonbeating atria from male Sprague-Dawley rats were used to evaluate stretch-activated ANP secretion in response to ET-1, ET-2, ET-3, and s6C. Changes in mean blood pressure (MAP) were measured during acute injection of ET-1 and ET-3 with and without natriuretic peptide receptor-A antagonist (A71915) in anesthetized rats. Changes in atrial volume induced by increased atrial pressure from o to 1, 2, 4, or 6cm H2O caused proportional increases in mechanically-stimulated extracellular fluid (ECF) translocation and stretch-activated ANP secretion. ET-1 (10nM) augmented basal and stretch-activated ANP secretion in terms of ECF translocation, which was blocked by the pretreatment with ETA receptor antagonist (BQ123, 1µM) but not by ETB receptor antagonist (BQ788, 1µM). ETA receptor antagonist itself suppressed stretch-activated ANP secretion. As compared to ET-1- induced ANP secretion (3.2-fold by 10nM), the secretagogue effects of ANP secretion by ET-2 was similar (2.8-fold by 10nM) and ET-3 and s6C were less potent (1.7-fold and 1.5-fold by 100nM, respectively). Acute injection of ET-1 or ET-3 increased mean blood pressure (MAP), which was augmented in the presence of natriuretic peptide receptor-A antagonist. Therefore, we suggest that the order of secretagogue effect of ET family on ANP secretion was ET-1≥ET-2>>ET-3>s6C and ET-1-induced ANP secretion negatively regulates the pressor effect of ET-1.
Asunto(s)
Factor Natriurético Atrial/metabolismo , Endotelinas/farmacología , Atrios Cardíacos/efectos de los fármacos , Péptidos/farmacología , Animales , Factor Natriurético Atrial/administración & dosificación , Presión Atrial/efectos de los fármacos , Presión Sanguínea/efectos de los fármacos , Endotelinas/química , Miocardio/metabolismo , Fragmentos de Péptidos/administración & dosificación , Péptidos/química , Ratas , Tetrahidroisoquinolinas/administración & dosificación , Venenos de Víboras/farmacologíaRESUMEN
Dipeptidyl peptidase-4 (DPP4) is one of the most potent mammalian serine proteases participated in the pathogenesis of subclinical atherosclerosis. Here we investigated whether the plasma soluble form of DPP4 is associated with the prevalence of coronary artery disease (CAD) with and without diabetes mellitus (DM). A cross-sectional study was conducted of 496 aged 26-81 years with (n = 362) and without (n = 134) CAD. Plasma DPP4 activity, high sensitive C-reactive protein (hs-CRP), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein levels were measured. The coronary atherosclerotic plaques were evaluated by coronary angiography. The CAD patients with (n = 84) and without (n = 278) DM had significantly higher DPP4 levels (11.8 ± 3.1 vs. 6.9 ± 3.5 ng/mL, P<0.01) than the nonCAD subjects. The acute coronary syndrome patients (n = 299) had elevated DPP4 levels than those with stable angina patients (n = 83). CAD patients even without DM had increased plasma DPP4 activities as compared with nonCAD subjects (10.9 ± 4.9 vs. 6.4 ± 3.1, ng/L, P< 0.01). A linear regression analysis revealed that overall, the DPP4 levels were positively associated with LCL-C and hs-CRP levels as well as syntax scores. A multiple logistic regression analysis demonstrated that plasma DPP4 activity was independent predictor of CAD (odds ratio, 1.56; 95% CI, 1.19-1.73; P<0.01). Our study shows that increased DPP4 activity levels are associated with the presence of CAD and that the plasma DPP4 level serves as a novel biomarker for CAD even without DM.
RESUMEN
Protein tyrosine phosphatase non-receptor type 12 (PTPN12) has been shown to be involved in the development of a number of types of carcinoma. However, the effect of PTPN12 on the proliferation and recurrence of human bladder transitional cell carcinoma (TCC) is unclear. The present study aimed to investigate the expression and function of PTPN12 in human TCC. Samples from 164 patients with TCC, in addition to 146 patients undergoing bladder surgery for indications other than TCC, were examined. PTPN12 protein expression was examined using immunohistochemistry and western blotting, and PTPN12 mRNA expression was examined using reverse transcription-quantitative polymerase chain reaction. PTPN12 expression was increased following transfection with the PTPN12-expressing, pcDEF3 vector, and PTPN12 expression was decreased by RNA interference, in four TCC cell lines. The proliferation of TCC cells was analyzed by a WST-1 assay and in xenografts on BALB/C nude mice. The effect of PTPN12 on tumor recurrence was analyzed by adhesion, migration and invasion assays in TCC cell lines. PTPN12 expression was significantly decreased in TCC tissues compared with that in normal urothelium, and the level of PTPN12 expression was negatively correlated with tumor size, pathological grade, clinical stage and tumor recurrence. Furthermore, decreased expression of PTPN12 significantly enhanced the proliferation of TCC cells in vitro and in vivo. TCC cells with lower levels of PTPN12 exhibited greater adhesion, migration and invasion. In conclusion, PTPN12 expression is downregulated in human TCC. Restoring PTPN12 activity may represent a novel therapeutic strategy for this disease.
RESUMEN
Cysteinyl cathepsin K (CatK) is one of the most potent mammalian collagenases involved in cardiovascular disease. Here, we investigated the clinical predictive value of serum CatK levels in patients with chronic heart failure (CHF). We examined 134 patients with CHF, measuring their serum CatK, troponin I, high-sensitive C-reactive protein, and pre-operative N-terminal pro-brain natriuretic peptide levels. The patients were divided into two groups: the 44 patients who showed a left ventricular (LV) ejection fraction (LVEF) < 40% (the "lowLVEF" group) and the 90 patients showing LVEF values ≥ 40% (the "highLVEF" group). The lowLVEF patients had significantly higher serum CatK levels compared to the highLVEF patients (58.4 ± 12.2 vs. 44.7 ± 16.4, P < 0.001). Overall, a linear regression analysis showed that CatK levels correlated negatively with LVEF (r = -0.4, P < 0.001) and positively with LV end-diastolic dimensions (r = 0.2, P < 0.01), LV end-systolic dimensions (r = 0.3, P < 0.001), and left atrial diameters (r = 0.3, P < 0.01). A multiple logistic regression analysis showed that CatK levels were independent predictors of CHF (odds ratio, 0.90; 95% confidence interval, 0.84-0.95; P < 0.01). These data indicate that elevated levels of CatK are closely associated with the presence of CHF and that the measurement of circulating CatK provides a noninvasive method of documenting and monitoring the extent of cardiac remodeling and dysfunction in patients with CHF.
Asunto(s)
Catepsina K/sangre , Insuficiencia Cardíaca/sangre , Hipertensión/sangre , Disfunción Ventricular Izquierda/sangre , Anciano , Proteína C-Reactiva/metabolismo , Ecocardiografía , Matriz Extracelular/genética , Femenino , Insuficiencia Cardíaca/fisiopatología , Humanos , Hipertensión/fisiopatología , Lipoproteínas , Masculino , Persona de Mediana Edad , Péptido Natriurético Encefálico/sangre , Análisis de Regresión , Troponina I/sangre , Disfunción Ventricular Izquierda/fisiopatologíaRESUMEN
Androgen levels are lower in obese men as compared with normal weight individuals. However, there are no safety data regarding the chronic use of androgen supplements in middle-aged men. The present study was undertaken to determine the cardiovascular and metabolic effects of chronic (10 weeks) testosterone treatment in male obese Zucker rats, starting at 22 weeks of age, when testosterone levels were significantly decreased. Testosterone supplements increased plasma levels, 10-fold in both obese Zucker rats and lean Zucker rats. In obese Zucker rats, testosterone supplements reduced body weight, plasma insulin, and cholesterol levels and improved the oral glucose tolerance test. None of these parameters were affected in lean Zucker rats. Mean arterial pressure was significantly increased in obese Zucker rats but not lean Zucker rats. Testosterone supplements increased proteinuria and accelerated renal injury in lean Zucker rats only. Thus, treatment of obese men with chronic testosterone supplements should be done with careful monitoring of blood pressure.
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Presión Sanguínea/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Suplementos Dietéticos , Resistencia a la Insulina , Insulina/sangre , Obesidad/dietoterapia , Testosterona/administración & dosificación , Andrógenos/administración & dosificación , Andrógenos/farmacocinética , Animales , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Masculino , Obesidad/fisiopatología , Ratas , Ratas Zucker , Factores de Riesgo , Testosterona/farmacocinéticaRESUMEN
Reactive oxygen species (ROS) are formed as a natural by-product of the normal metabolism of oxygen and have important roles in cell signaling. The aim of this study was to investigate direct effects of ROS on atrial hemodynamics and ANP secretion in isolated perfused beating rat atria with antioxidants. When atria were paced at 1.2 Hz, N-acetyl cystein (antioxidant, NAC), α-lipoic acid (antioxidant), tempol (superoxide dismutase mimic), and apocynin (NADPH oxidase inhibitor; NOX inhibitor) did not affect ANP secretion and atrial contractility. When pacing frequency was increased from 1.2 Hz to 4 Hz, the ANP secretion increased and atrial contractility decreased. H(2)O(2) level was increased in perfusate obtained from atria stimulated by high pacing frequency. NAC, α-lipoic acid and tempol attenuated high pacing frequency-induced ANP secretion but apocynin did not. In contrast, pyrogallol (a superoxide generator) augmented high pacing frequency-induced ANP secretion. NOX-4 protein was increased by high pacing stimulation and in diabetic rat atria. In diabetic rat atria, high pacing frequency caused an increased ANP secretion and a decreased atrial contractility, that were markedly attenuated as compared to control rats. NAC and apocynin reduced high pacing frequency-induced ANP secretion in diabetic rat atria. These results suggest that intracellular ROS formation partly through an increasing NOX activity in response to high pacing frequency is associated with an increased ANP secretion in rat atria.
Asunto(s)
Acetilcisteína/farmacología , Antioxidantes/farmacología , Factor Natriurético Atrial/metabolismo , Atrios Cardíacos/metabolismo , Acetofenonas/farmacología , Animales , Función Atrial/efectos de los fármacos , Presión Sanguínea , Estimulación Cardíaca Artificial , Óxidos N-Cíclicos/farmacología , Diabetes Mellitus Experimental/metabolismo , Estimulación Eléctrica , Activación Enzimática , Líquido Extracelular/metabolismo , Atrios Cardíacos/efectos de los fármacos , Hemodinámica , Peróxido de Hidrógeno/farmacología , Técnicas In Vitro , Masculino , Contracción Miocárdica/efectos de los fármacos , NADPH Oxidasa 4 , NADPH Oxidasas/antagonistas & inhibidores , NADPH Oxidasas/metabolismo , Pirogalol/farmacología , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/farmacología , Marcadores de Spin , Ácido Tióctico/farmacologíaRESUMEN
OBJECTIVES: The aim of the present studywas to examine the question of whether the atrial natriuretic peptide (ANP) system is altered by endothelial nitric-oxide synthase (eNOS). METHODS: Male eNOS-deficient mice (eNOS-/-) and wild type control mice (eNOS+/+, C57B1/6J) were used. Blood pressure was measured in anesthetized mice by tail cuff plethysmography and renal function was measured. Expression of ANP, natriuretic peptide receptor (NPR)-A, NPR-C, and tonicity-responsive enhancer binding protein (TonEBP) mRNA was determined by real-time PCR. Localization of (125)I-ANP binding sites was measured using in vitro autoradiography. RESULTS: In eNOS-/- mice, systolic blood pressure increased and left ventricular hypertrophy was observed. Urine volume and osmolarity did not change. Expression of ANP markedly increased in the heart and kidney of eNOS-/- mice. Expression of NPR-A and NPR-C increased in the heart and tended to increase in the kidney of eNOS-/- mice. In the renal medulla in particular, increased expression of NPR-C was more prominent. Expression of TonEBP mRNA was markedly decreased in the renal medulla, but not in the renal cortex. Maximum binding capacity (B(max)) of ANP and C-ANP increased in the renal medulla in eNOS-/- mice. CONCLUSION: These results suggest that the eNOS-NO system may be partly involved in regulation of ANP, NPR-A, -C, and TonEBP mRNA expression in the kidney.