RESUMO
Alamandine is a heptapeptide from the renin-angiotensin system (RAS) with similar structure/function to angiotensin-(1-7) [ang-(1-7)], but they act via different receptors. It remains elusive whether alamandine is an antiproliferative agent like ang-(1-7). The goal of this study was to evaluate the potential antiproliferative activity of alamandine and the underlying cellular signaling. We evaluated alamandine effect in the tumoral cell lines Mia PaCa-2 and A549, and in the nontumoral cell lines HaCaT, CHO and CHO transfected with the alamandine receptor MrgD (CHO-MrgD). Alamandine was able to reduce the proliferation of the tumoral cell lines in a MrgD-dependent fashion. We did not observe any effect in the nontumoral cell lines tested. We also performed proteomics and phosphoproteomics to study the alamandine signaling in Mia PaCa-2 and CHO-MrgD. Data suggest that alamandine induces a shift from anaerobic to aerobic metabolism in the tumoral cells, induces a negative regulation of PI3K/AKT/mTOR pathway and activates the transcriptional factor FoxO1; events that could explain, at least partially, the observed antiproliferative effect of alamandine. This study provides for the first time a comprehensive investigation of the alamandine signaling in tumoral (Mia PaCa-2) and nontumoral (CHO-MrgD) cells, highlighting the antiproliferative activity of alamandine/MrgD and its possible antitumoral effect.
Assuntos
Fosfatidilinositol 3-Quinases , Receptores Acoplados a Proteínas G , Humanos , Oligopeptídeos/metabolismo , Oligopeptídeos/farmacologia , Neoplasias Pancreáticas , Receptores Acoplados a Proteínas G/metabolismo , Neoplasias PancreáticasRESUMO
Anormalidades da anatomia orofacial estão envolvidas na patogênese da Apnéia Obstrutiva do Sono porfacilitarem o fechamento das vias áreas. O estudo objetivou associar a presença de alterações orofaciais ao risco deApnéia Obstrutiva do Sono em hipertensos. 95 indivíduos (46% homens e 54% mulheres, 64 ± 10 anos) foram avaliadosquanto à distância tireomentoniana, Mallampati, palato ogival, grau de Angle, índice de massa corpórea, circunferênciasabdominal e pescoço. O risco para Apnéia Obstrutiva do Sono foi obtido pelo Questionário de Berlim.Foram observadosíndice de massa corpórea de 30 ± 5 Kg/m2, circunferência abdominal de 101 ± 12 cm e do pescoço 39 ± 3cm. Correlaçõespositivas foram observadas entre classificação de Mallampati, circunferências abdominal e do pescoço (p= 0,025 e 0,03,respectivamente). Pelo Questionário de Berlim, 46 indivíduos (48%) apresentavam alto risco, dos quais76% classificadoscomo Mallampati III/ IV, 69% distância tireomentoniana < 6 cm, 26% Angle II e 10% palato ogival. A prevalência dealterações orofaciais foi maior nos indivíduos comrisco elevado (93%) do que nos de baixo risco (50%). Alterações naanatomia orofacial, particularmente Mallampati, reiteram risco de Apnéia Obstrutiva do Sono e podem facilitar a triagemclínica como diagnóstico precoce.
Assuntos
Humanos , Masculino , Feminino , Anormalidades Maxilofaciais/complicações , Fatores de Risco , Hipertensão , Síndromes da Apneia do SonoRESUMO
Angiotensin-(1-7) [Ang-(1-7)] causes endothelial-dependent vasodilation mediated, in part, by NO release. However, the molecular mechanisms involved in endothelial NO synthase (eNOS) activation by Ang-(1-7) remain unknown. Using Chinese hamster ovary cells stably transfected with Mas cDNA (Chinese hamster ovary-Mas), we evaluated the underlying mechanisms related to receptor Mas-mediated posttranslational eNOS activation and NO release. We further examined the Ang-(1-7) profile of eNOS activation in human aortic endothelial cells, which constitutively express the Mas receptor. Chinese hamster ovary-Mas cells and human aortic endothelial cell were stimulated with Ang-(1-7; 10(-7) mol/L; 1 to 30 minutes) in the absence or presence of A-779 (10(-6) mol/L). Additional experiments were performed in the presence of the phosphatidylinositol 3-kinase inhibitor wortmannin (10(-6) mol/L). Changes in eNOS (at Ser1177/Thr495 residues) and Akt phosphorylation were evaluated by Western blotting. NO release was measured using both the fluorochrome 2,3-diaminonaphthalene and an NO analyzer. Ang-(1-7) significantly stimulated eNOS activation (reciprocal phosphorylation/dephosphorylation at Ser1177/Thr495) and induced a sustained Akt phosphorylation (P<0.05). Concomitantly, a significant increase in NO release was observed (2-fold increase in relation to control). These effects were blocked by A-779. Wortmannin suppressed eNOS activation in both Chinese hamster ovary-Mas and human aortic endothelial cells. Our findings demonstrate that Ang-(1-7), through Mas, stimulates eNOS activation and NO production via Akt-dependent pathways. These novel data highlight the importance of the Ang-(1-7)/Mas axis as a putative regulator of endothelial function.
Assuntos
Angiotensina I/fisiologia , Óxido Nítrico Sintase Tipo III/metabolismo , Fragmentos de Peptídeos/fisiologia , Proteínas Proto-Oncogênicas c-akt/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Receptores Acoplados a Proteínas G/fisiologia , Angiotensina I/farmacologia , Animais , Aorta/citologia , Células CHO/metabolismo , Células Cultivadas , Cricetinae , Cricetulus , Células Endoteliais/metabolismo , Ativação Enzimática/fisiologia , Humanos , Óxido Nítrico/metabolismo , Fragmentos de Peptídeos/farmacologia , Fosforilação , Processamento de Proteína Pós-Traducional/fisiologia , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/genética , Receptores Acoplados a Proteínas G/genética , TransfecçãoRESUMO
It has been described recently that the nonpeptide AVE 0991 (AVE) mimics the effects of angiotensin-(1-7) [Ang-(1-7)] in bovine endothelial cells. In this study, we tested the possibility that AVE is an agonist of the Ang-(1-7) receptor Mas, in vitro and in vivo. In water-loaded C57BL/6 mice, AVE (0.58 nmol/g body weight) produced a significant reduction in urinary volume (0.06+/-0.03 mL/60 min [n=9] versus 0.27+/-0.05 [n=9]; P<0.01), associated with an increase in urinary osmolality. The Ang-(1-7) antagonist A-779 completely blocked the antidiuretic effect of AVE. As observed previously for Ang-(1-7), the antidiuretic effect of AVE after water load was blunted in Mas-knockout mice (0.37+/-0.10 mL/60 min [n=9] versus 0.27+/-0.03 mL/60 min [n=11] AVE-treated mice). In vitro receptor autoradiography in C57BL/6 mice showed that the specific binding of 125I-Ang-(1-7) to mouse kidney slices was displaced by AVE, whereas no effects were observed in the binding of 125I-angiotensin II or 125I-angiotensin IV. Furthermore, AVE displaced the binding of 125I-Ang-(1-7) in Mas-transfected monkey kidney cells (COS) cells (IC50=4.75x10(-8) mol/L) and of rhodamine-Ang-(1-7) in Mas-transfected Chinese hamster ovary (CHO) cells. It also produced NO release in Mas-transfected CHO cells blocked by A-779 but not by angiotensin II type-1 (AT1) and AT2 antagonists. Contrasting with these data, the antidiuretic effect of AVE was totally blocked by AT2 antagonists and partially blocked (approximately 60%) by AT1 antagonists. The binding data, the results obtained in Mas-knockout mice and in Mas-transfected cells, show that AVE is a Mas receptor agonist. Our data also suggest the involvement of AT2/AT1-related mechanisms, including functional antagonism, oligomerization or cross-talk, in the renal responses to AVE.