RESUMO
The correct regulation of tissue barriers is of utmost importance for health. Barrier dysfunction accompanies inflammatory disorders and, if not controlled properly, can contribute to the development of chronic diseases. Tissue barriers are formed by monolayers of epithelial cells that separate organs from their environment, and endothelial cells that cover the vasculature, thus separating the blood stream from underlying tissues. Cells within the monolayers are connected by intercellular junctions that are linked by adaptor molecules to the cytoskeleton, and the regulation of these interactions is critical for the maintenance of tissue barriers. Many endogenous and exogenous molecules are known to regulate barrier functions in both ways. Proinflammatory cytokines weaken the barrier, whereas anti-inflammatory mediators stabilize barriers. Adrenomedullin (ADM) and intermedin (IMD) are endogenous peptide hormones of the same family that are produced and secreted by many cell types during physiologic and pathologic conditions. They activate certain G-protein-coupled receptor complexes to regulate many cellular processes such as cytokine production, actin dynamics and junction stability. In this review, we summarize current knowledge about the barrier-stabilizing effects of ADM and IMD in health and disease.
Assuntos
Adrenomedulina/metabolismo , Células Endoteliais/metabolismo , Junções Intercelulares/metabolismo , Adrenomedulina/química , Adrenomedulina/genética , Animais , Células Endoteliais/citologia , Humanos , Receptores de Adrenomedulina/metabolismo , Transdução de SinaisRESUMO
The aim of the present study was to determine the mechanisms underlying the relaxant effect of adrenomedullin (AM) in rat cavernosal smooth muscle (CSM) and the expression of AM system components in this tissue. Functional assays using standard muscle bath procedures were performed in CSM isolated from male Wistar rats. Protein and mRNA levels of pre-pro-AM, calcitonin receptor-like receptor (CRLR), and Subtypes 1, 2 and 3 of the receptor activity-modifying protein (RAMP) family were assessed by Western immunoblotting and quantitative real-time polymerase chain reaction, respectively. Nitrate and 6-keto-prostaglandin F1α (6-keto-PGF1α; a stable product of prostacyclin) levels were determined using commercially available kits. Protein and mRNA of AM, CRLR, and RAMP 1, -2, and -3 were detected in rat CSM. Immunohistochemical assays demonstrated that AM and CRLR were expressed in rat CSM. AM relaxed CSM strips in a concentration-dependent manner. AM22-52, a selective antagonist for AM receptors, reduced the relaxation induced by AM. Conversely, CGRP8-37, a selective antagonist for calcitonin gene-related peptide receptors, did not affect AM-induced relaxation. Preincubation of CSM strips with NG-nitro-L-arginine-methyl-ester (L-NAME, nitric oxide synthase inhibitor), 1H-(1,2,4)oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, quanylyl cyclase inhibitor), Rp-8-Br-PET-cGMPS (cGMP-dependent protein kinase inhibitor), SC560 [5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethyl pyrazole, selective cyclooxygenase-1 inhibitor], and 4-aminopyridine (voltage-dependent K+ channel blocker) reduced AM-induced relaxation. On the other hand, 7-nitroindazole (selective neuronal nitric oxide synthase inhibitor), wortmannin (phosphatidylinositol 3-kinase inhibitor), H89 (protein kinase A inhibitor), SQ22536 [9-(tetrahydro-2-furanyl)-9H-purin-6-amine, adenylate cyclase inhibitor], glibenclamide (selective blocker of ATP-sensitive K+ channels), and apamin (Ca2+-activated channel blocker) did not affect AM-induced relaxation. AM increased nitrate levels and 6-keto-PGF1α in rat CSM. The major new contribution of this research is that it demonstrated expression of AM and its receptor in rat CSM. Moreover, we provided evidence that AM-induced relaxation in this tissue is mediated by AM receptors by a mechanism that involves the nitric oxide-cGMP pathway, a vasodilator prostanoid, and the opening of voltage-dependent K+ channels.
Assuntos
Animais , Masculino , Adrenomedulina/farmacologia , Proteína Semelhante a Receptor de Calcitonina/análise , Músculo Liso/efeitos dos fármacos , Parassimpatolíticos/farmacologia , Pênis/efeitos dos fármacos , Vasodilatadores/farmacologia , /farmacologia , /análise , Adrenomedulina/genética , Adrenomedulina/metabolismo , Western Blotting , Proteína Semelhante a Receptor de Calcitonina/antagonistas & inibidores , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Inibidores de Ciclo-Oxigenase/farmacologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Imuno-Histoquímica , Indazóis/farmacologia , Relaxamento Muscular , Músculo Liso/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico/análise , Óxido Nítrico/análogos & derivados , Pênis/metabolismo , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , RNA Mensageiro/metabolismo , Proteína 1 Modificadora da Atividade de Receptores/genética , Proteína 1 Modificadora da Atividade de Receptores/metabolismo , /metabolismo , /genética , /metabolismo , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/metabolismoRESUMO
The aim of the present study was to determine the mechanisms underlying the relaxant effect of adrenomedullin (AM) in rat cavernosal smooth muscle (CSM) and the expression of AM system components in this tissue. Functional assays using standard muscle bath procedures were performed in CSM isolated from male Wistar rats. Protein and mRNA levels of pre-pro-AM, calcitonin receptor-like receptor (CRLR), and Subtypes 1, 2 and 3 of the receptor activity-modifying protein (RAMP) family were assessed by Western immunoblotting and quantitative real-time polymerase chain reaction, respectively. Nitrate and 6-keto-prostaglandin F(1α) (6-keto-PGF(1α); a stable product of prostacyclin) levels were determined using commercially available kits. Protein and mRNA of AM, CRLR, and RAMP 1, -2, and -3 were detected in rat CSM. Immunohistochemical assays demonstrated that AM and CRLR were expressed in rat CSM. AM relaxed CSM strips in a concentration-dependent manner. AM(22-52), a selective antagonist for AM receptors, reduced the relaxation induced by AM. Conversely, CGRP(8-37), a selective antagonist for calcitonin gene-related peptide receptors, did not affect AM-induced relaxation. Preincubation of CSM strips with N(G)-nitro-L-arginine-methyl-ester (L-NAME, nitric oxide synthase inhibitor), 1H-(1,2,4)oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, quanylyl cyclase inhibitor), Rp-8-Br-PET-cGMPS (cGMP-dependent protein kinase inhibitor), SC560 [5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethyl pyrazole, selective cyclooxygenase-1 inhibitor], and 4-aminopyridine (voltage-dependent K(+) channel blocker) reduced AM-induced relaxation. On the other hand, 7-nitroindazole (selective neuronal nitric oxide synthase inhibitor), wortmannin (phosphatidylinositol 3-kinase inhibitor), H89 (protein kinase A inhibitor), SQ22536 [9-(tetrahydro-2-furanyl)-9H-purin-6-amine, adenylate cyclase inhibitor], glibenclamide (selective blocker of ATP-sensitive K(+) channels), and apamin (Ca(2+)-activated channel blocker) did not affect AM-induced relaxation. AM increased nitrate levels and 6-keto-PGF1α in rat CSM. The major new contribution of this research is that it demonstrated expression of AM and its receptor in rat CSM. Moreover, we provided evidence that AM-induced relaxation in this tissue is mediated by AM receptors by a mechanism that involves the nitric oxide-cGMP pathway, a vasodilator prostanoid, and the opening of voltage-dependent K(+) channels.
Assuntos
Adrenomedulina/farmacologia , Proteína Semelhante a Receptor de Calcitonina/análise , Músculo Liso/efeitos dos fármacos , Parassimpatolíticos/farmacologia , Pênis/efeitos dos fármacos , Vasodilatadores/farmacologia , 4-Aminopiridina/farmacologia , 6-Cetoprostaglandina F1 alfa/análise , Adrenomedulina/genética , Adrenomedulina/metabolismo , Animais , Western Blotting , Proteína Semelhante a Receptor de Calcitonina/antagonistas & inibidores , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Inibidores de Ciclo-Oxigenase/farmacologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Imuno-Histoquímica , Indazóis/farmacologia , Masculino , Relaxamento Muscular , Músculo Liso/metabolismo , Óxido Nítrico/análogos & derivados , Óxido Nítrico/análise , Óxido Nítrico Sintase/antagonistas & inibidores , Pênis/metabolismo , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , RNA Mensageiro/metabolismo , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Proteína 1 Modificadora da Atividade de Receptores/genética , Proteína 1 Modificadora da Atividade de Receptores/metabolismo , Proteína 2 Modificadora da Atividade de Receptores/genética , Proteína 2 Modificadora da Atividade de Receptores/metabolismo , Proteína 3 Modificadora da Atividade de Receptores/metabolismo , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/metabolismoRESUMO
Adrenomedullin (AM) is a peptide that displays cardiovascular protective activity. We investigated the effects of chronic ethanol consumption on vascular reactivity to AM and the expression of AM system components in the rat aorta. Male Wistar rats were treated with ethanol (20% vol/vol) for 6 weeks. Vascular reactivity experiments were performed in the isolated rat aorta. Metalloproteinase-2 (MMP-2) levels were determined by gelatin zymography. Nitrite and nitrate generation was measured by chemiluminescence. Protein and mRNA levels of pre-pro-AM, calcitonin receptor-like receptor (CRLR) and RAMP1, 2, and 3 (receptor-activity-modifying proteins) were assessed by western blot and quantitative real-time polymerase chain reaction, respectively. Ethanol intake reduced AM-induced relaxation in endothelium-intact rat aortas, whereas calcitonin gene-related peptide-, acetylcholine-, and sodium nitroprusside-induced relaxation were not affected by ethanol intake. N(G)-nitro-l-arginine-methyl-ester (l-NAME), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, and tetraethylammonium reduced AM-induced relaxation in aortic rings from both control and ethanol-treated rats. Ethanol consumption did not alter basal levels of nitrate and nitrite, nor did it affect the expression of MMP-2 in the rat aorta. Ethanol consumption increased mRNA levels of pre-pro-AM and RAMP1. Protein levels of AM, CRLR, and RAMP1, 2, and 3 were not affected by ethanol consumption. The major findings of the present study are that ethanol consumption reduces the vascular relaxation induced by AM and changes the mRNA expression of the components of the AM system in the vasculature. This response could be one of the mechanisms by which ethanol predisposes individuals to vascular dysfunction and hypertension.
Assuntos
Adrenomedulina/farmacologia , Aorta/efeitos dos fármacos , Etanol/administração & dosagem , Vasodilatadores/farmacologia , Adrenomedulina/genética , Adrenomedulina/fisiologia , Alcoolismo/complicações , Alcoolismo/fisiopatologia , Animais , Aorta/fisiopatologia , Etanol/sangue , Expressão Gênica/efeitos dos fármacos , Masculino , RNA Mensageiro/análise , Ratos , Ratos WistarRESUMO
Blood samples are used as a biological source to discover biomarkers of hematological and non-hematological disorders. The present study shows the impact of different experimental conditions associated with cell lysis buffer, TRI-reagent protocol and blood cell storage buffer and their correlation with the quantity, quality and Adrenomedullin gene expression levels of total RNA when RT-PCR technique is used. A leukocyte cell bank protocol is also proposed for further mRNA expression analysis using RNAlater as storage buffer. There is evidence that total RNA isolated from leukocyte concentrate stored for 1 month at -70 degrees C did not show significant differences concerning quality, purity and Adrenomedullin gene expression compared with the freshly processed leukocyte sample.
Assuntos
Preservação de Sangue , Leucócitos/química , RNA Mensageiro/análise , RNA/sangue , Adrenomedulina/genética , Soluções Tampão , Perfilação da Expressão Gênica , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Twenty-four 1-d-old broilers were distributed in 2 groups, pulmonary hypertensive broilers (PHB) and pulmonary nonhypertensive broilers (NPHB), to estimate possible differences between them in the expression of endothelin 1 (ET-1) and its type A receptor, connective tissue growth factor, platelet-derived growth factor, and adrenomedullin expression in the lungs. For this purpose, total RNA extraction and real-time PCR analysis were used. Endothelin 1 mRNA levels in the lungs of PHB were significantly higher than the corresponding level in NPHB (P < 0.001). In contrast, the opposite was true for ET-1 type A receptor mRNA levels (P < 0.001). Connective tissue growth factor mRNA levels in the lungs of PHB were significantly higher than in the lungs of NPHB (P < 0.01). However, no differences were encountered between the 2 groups of broilers in platelet-derived growth factor mRNA expression (P > 0.05). Adrenomedullin mRNA levels in the lungs of PHB were significantly higher than in NPHB (P < 0.01). It has been demonstrated for the first time that ET-1, connective tissue growth factor, and adrenomedullin are upregulated in the lungs of PHB. Furthermore, it is suggested that these peptides may play a major role in pulmonary hypertension pathophysiology. Present data might provide clues for future research directions such as genetic selection and therapeutic intervention to revert the process of pulmonary vasoconstriction and vascular remodeling. Major research goals could be to find endothelium-derived factors that probably trigger endothelial dysfunction, as well as possible interactions with already identified molecules which also intervene in the pulmonary response to hypoxia.
Assuntos
Adrenomedulina/genética , Galinhas/genética , Endotelina-1/genética , Hipertensão Pulmonar/veterinária , Proteínas Imediatamente Precoces/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Pulmão/metabolismo , Fator de Crescimento Derivado de Plaquetas/genética , Receptor de Endotelina A/genética , Animais , Fator de Crescimento do Tecido Conjuntivo , Regulação da Expressão Gênica , Hipertensão Pulmonar/genética , Pulmão/fisiologia , Pulmão/fisiopatologia , Masculino , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/fisiopatologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
Blood samples are used as a biological source to discover biomarkers of hematological and non-hematological disorders. The present study shows the impact of different experimental conditions associated with cell lysis buffer, TRI-reagent protocol and blood cell storage buffer and their correlation with the quantity, quality and Adrenomedullin gene expression levels of total RNA when RT-PCR technique is used. A leukocyte cell bank protocol is also proposed for further mRNA expression analysis using RNAlater as storage buffer. There is evidence that total RNA isolated from leukocyte concentrate stored for 1 month at -70 degrees C did not show significant differences concerning quality, purity and Adrenomedullin gene expression compared with the freshly processed leukocyte sample.