Asunto(s)
Sistema Cardiovascular , Ejercicio Físico , Sistema Inmunológico , Riñón , Músculo Esquelético , Enfermedades no Transmisibles/prevención & control , Factores de Edad , Envejecimiento , Animales , Sistema Cardiovascular/inmunología , Sistema Cardiovascular/metabolismo , Sistema Cardiovascular/fisiopatología , Humanos , Sistema Inmunológico/inmunología , Sistema Inmunológico/metabolismo , Sistema Inmunológico/fisiopatología , Riñón/inmunología , Riñón/metabolismo , Riñón/fisiopatología , Contracción Muscular , Músculo Esquelético/inmunología , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiopatología , Enfermedades no Transmisibles/epidemiología , Factores de Riesgo , Conducta Sedentaria , Transducción de SeñalAsunto(s)
Lesión Renal Aguda , Riñón/irrigación sanguínea , Insuficiencia Renal Crónica , Daño por Reperfusión/terapia , Lesión Renal Aguda/diagnóstico , Lesión Renal Aguda/metabolismo , Lesión Renal Aguda/terapia , Animales , Humanos , Isquemia/terapia , Insuficiencia Renal Crónica/diagnóstico , Insuficiencia Renal Crónica/metabolismo , Insuficiencia Renal Crónica/terapia , Daño por Reperfusión/diagnóstico , Factores de RiesgoAsunto(s)
Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/prevención & control , Síndrome Metabólico/epidemiología , Síndrome Metabólico/prevención & control , Obesidad/epidemiología , Obesidad/prevención & control , Enfermedades Cardiovasculares/diagnóstico , Humanos , Incidencia , Síndrome Metabólico/diagnóstico , Obesidad/diagnóstico , Medición de RiesgoRESUMEN
AIM: In the present study, we aimed to elucidate the effects of chronic vasopressin administration on renal medullary oxygen levels. METHODS: Adult Sprague Dawley or vasopressin-deficient Brattleboro rats were treated with the vasopressin V2 receptor agonist, desmopressin (5 ng/h; 3d), or its vehicle via osmotic minipumps. Immunostaining for pimonidazole and the transcription factor HIF-1α (hypoxia-inducible factor-1α) were used to identify hypoxic areas. Activation of HIF-target gene expression following desmopressin treatment was studied by microarray analysis. RESULTS: Pimonidazole staining was detected in the outer and inner medulla of desmopressin-treated rats, whereas staining in control animals was weak or absent. HIF-1α immunostaining demonstrated nuclear accumulation in the papilla of desmopressin-treated animals, whereas no staining was observed in the controls. Gene expression analysis revealed significant enrichment of HIF-target genes in the group of desmopressin-regulated gene products (P = 2.6*10(-21) ). Regulated products included insulin-like growth factor binding proteins 1 and 3, angiopoietin 2, fibronectin, cathepsin D, hexokinase 2 and cyclooxygenase 2. CONCLUSION: Our results demonstrate that an activation of the renal urine concentrating mechanism by desmopressin causes renal medullary hypoxia and an upregulation of hypoxia-inducible gene expression.
Asunto(s)
Hipoxia/metabolismo , Médula Renal/metabolismo , Oxígeno/metabolismo , Receptores de Vasopresinas/fisiología , Transducción de Señal/fisiología , Animales , Desamino Arginina Vasopresina/farmacología , Modelos Animales de Enfermedad , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Médula Renal/efectos de los fármacos , Nitroimidazoles/metabolismo , Ratas , Ratas Brattleboro , Ratas Sprague-Dawley , Receptores de Vasopresinas/agonistas , Receptores de Vasopresinas/efectos de los fármacos , Vasopresinas/deficiencia , Vasopresinas/genética , Vasopresinas/metabolismoRESUMEN
Na(+)-K(+)-2Cl(-) cotransporter (NKCC2)-mediated NaCl reabsorption in the thick ascending limb (TAL) is stimulated by AVP via V2 receptor/PKA/cAMP signaling. This process is antagonized by locally produced eicosanoids such as 20-HETE or prostaglandin E(2), which are synthesized in a phospholipase A(2)-dependent reaction cascade. Using microarray-based gene expression analysis, we found evidence for an AVP-dependent downregulation of the calcium-independent isoform of PLA(2), iPLA(2)ß, in the outer medulla of rats. In the present study, we therefore examined the contribution of iPLA(2)ß to NKCC2 regulation. Immunoreactive iPLA(2)ß protein was detected in cultured mTAL cells as well as in the entire TAL of rodents and humans with the exception of the macula densa. Administration of the V2 receptor-selective agonist desmopressin (5 ng/h; 3 days) to AVP-deficient diabetes insipidus rats increased outer medullary phosphorylated NKCC2 (pNKCC2) levels more than twofold in association with a marked reduction in iPLA(2)ß abundance (-65%; P < 0.05), thus confirming microarray results. Inhibition of iPLA(2)ß in Sprague-Dawley rats with FKGK 11 (0.5 µM) or in mTAL cells with FKGK 11 (10 µM) or (S)-bromoenol lactone (5 µM) for 1 h markedly increased pNKCC2 levels without affecting total NKCC2 expression. Collectively, these data indicate that iPLA(2)ß acts as an inhibitory modulator of NKCC2 activity and suggest that downregulation of iPLA(2)ß may be a relevant step in AVP-mediated urine concentration.
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Fosfolipasas A2 Grupo VI/metabolismo , Asa de la Nefrona/metabolismo , Simportadores de Cloruro de Sodio-Potasio/metabolismo , Vasopresinas/metabolismo , Animales , Anticuerpos , Ácidos Araquidónicos , Células Cultivadas , Desamino Arginina Vasopresina , Regulación hacia Abajo , Fluorocarburos , Expresión Génica , Fosfolipasas A2 Grupo VI/inmunología , Cobayas , Humanos , Isoenzimas , Cetonas , Médula Renal/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Naftalenos , Organofosfonatos , Fosforilación , Pironas , Ratas , Ratas Brattleboro , Ratas Sprague-Dawley , Miembro 1 de la Familia de Transportadores de Soluto 12RESUMEN
Adenosine (Ado) mediates vasoconstriction via A(1)-Ado receptors and vasodilation via A(2)-Ado receptors in the kidney. It interacts with angiotensin II (Ang II), which is important for renal hemodynamics and tubuloglomerular feedback (TGF). The aim was to investigate the function of Ado receptors in the Ado-Ang II interaction in mouse microperfused, afferent arterioles. Ado (10(-11)-10(-4) mol/l) caused a biphasic response: arteriolar diameters were reduced (-7%) at Ado 10(-11)-10(-9) mol/l and returned to control values at higher concentrations. Treatment with Ang II (10(-10) mol/l) transformed the response into a concentration-dependent constriction. N(6)-cyclopentyladenosine (A(1)-Ado receptor agonist) reduced diameters (12% at 10(-6) mol/l). Application of CGS21680 (10(-12)-10(-4) mol/l, A(2A) receptor agonist) increased the diameter by 13%. Pretreatment with ZM241385 (A(2A)-Ado receptor antagonist) alone or in combination with MRS1706 (A(2B)-Ado receptor antagonist) resulted in a pure constriction upon Ado, whereas 8-cyclopentyltheophylline (CPT) (A(1)-Ado receptor antagonist) inhibited the constrictor response. Afferent arterioles of mice lacking A(1)-Ado receptor did not show constriction upon Ado. Treatment with Ado (10(-8) mol/l) increased the response upon Ang II, which was blocked by CPT. Ado (10(-5) mol/l) did not influence the Ang II response, but an additional blockade of A(2)-Ado receptors enhanced it. The action of Ado on constrictor A(1)-Ado receptors and dilatory A(2)-Ado receptors modulates the interaction with Ang II. Both directions of Ado-Ang II interaction, which predominantly leads to an amplification of the contractile response, are important for the operation of the TGF.
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Adenosina/fisiología , Angiotensina II/fisiología , Arteriolas/fisiología , Glomérulos Renales/fisiología , Túbulos Renales/fisiología , Receptor de Adenosina A1/fisiología , Receptores de Adenosina A2/fisiología , Adenosina/análogos & derivados , Adenosina/farmacología , Agonistas del Receptor de Adenosina A1 , Antagonistas del Receptor de Adenosina A1 , Agonistas del Receptor de Adenosina A2 , Antagonistas del Receptor de Adenosina A2 , Animales , Retroalimentación/efectos de los fármacos , Retroalimentación/fisiología , Femenino , Glomérulos Renales/irrigación sanguínea , Túbulos Renales/irrigación sanguínea , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fenetilaminas/farmacología , Purinas/farmacología , Receptor de Adenosina A1/efectos de los fármacos , Receptores de Adenosina A2/efectos de los fármacos , Teofilina/análogos & derivados , Teofilina/farmacología , Triazinas/farmacología , Triazoles/farmacología , Vasoconstricción/efectos de los fármacos , Vasoconstricción/fisiología , Vasodilatación/efectos de los fármacos , Vasodilatación/fisiologíaRESUMEN
AIM: Efferent arterioles (Ef) are one of the final control elements in glomerular haemodynamics. The influence of nitric oxide (NO) on Ef remains ambiguous. METHODS: To test the hypothesis that endothelial NO plays an important role in this context, afferent arterioles (Af) and Ef of wild-type mice (WT), and Ef of mice lacking the endothelial NO synthetase [eNOS(-/-)] were perfused. Perfusion was performed in Ef via Af (orthograde) as well as from the distal end of Ef (retrograde), which provides an estimate for the importance of substances derived from the glomerulus. Angiotensin II (Ang II) was added in doses ranging from 10(-12) to 10(-6) mol L(-1) to the bath solution. RESULTS: Ang II reduced the luminal diameter of Af to 68 +/- 7 and in Ef to 55 +/- 8% during orthograde, and to 35 +/- 6% during retrograde perfusion (10(-6) mol L(-1) Ang II) in WT. Pre-treatment with N(G)-Nitro-L-arginine-methylester (l-NAME) (10(-4) mol L(-1)) increased the Ang II sensitivity in retrograde (17 +/- 9%) and orthograde perfused Ef (19 +/- 9%). The Ang II sensitivity was enhanced in eNOS(-/-) mice compared with WT, too. Already at a dose of Ang II 10(-9) mol L(-1), luminal diameters diminished to 8 +/- 7 and 7 +/- 4%. CONCLUSION: The increased Ang II sensitivity during L-NAME pre-treatment and in eNOS(-/-) mice indicates a strong counteraction of endothelial derived NO on Ang II induced contraction in Ef. Moreover, Ef are similarly sensitive to Ang II during either retrograde or orthograde perfusion in the absence of NO effects, suggesting that NO mediates, at least in part, the action of potential vasodilatory substances from the glomerulus.
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Angiotensina II/farmacología , Riñón/irrigación sanguínea , Óxido Nítrico/fisiología , Vasoconstricción/fisiología , Animales , Arteriolas/efectos de los fármacos , Arteriolas/fisiología , Relación Dosis-Respuesta a Droga , Técnicas In Vitro , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico Sintasa/genética , Óxido Nítrico Sintasa/fisiología , Óxido Nítrico Sintasa de Tipo II , Óxido Nítrico Sintasa de Tipo III , Vasoconstricción/efectos de los fármacosRESUMEN
Advances in technology have enabled us to take a fresh look at data acquired by traditional single experiments and to compare them with genomewide data. The differences can be tremendous, as we show here, in the field of proteomics. We have compared data sets of protein-protein interactions in Saccharomyces cerevisiae that were detected by an identical underlying technical method, the yeast two-hybrid system. We found that the individually identified protein-protein interactions are considerably different from those identified by two genomewide scans. Interacting proteins in the pooled database from single publications are much more closely related to each other with respect to transcription profiles when compared to genomewide data. This difference may have been introduced by two factors: by a selection process in individual publications and by false positives in the whole-genome scans. If we assume that the differences are a result of false positives in the whole-genome data, the scans would contain 47%, 44%, and 91% of false positives for the UETZ, ITO-core, and ITO-full data, respectively. If, however, the true fraction of false positives is considerably lower than estimated here, the data from hypothesis-driven experiments must have been subjected to a serious selection process.
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Proteínas Fúngicas/genética , Genoma Fúngico , Proteoma/genética , Saccharomyces cerevisiae/genética , Reacciones Falso Positivas , Mapeo de Interacción de Proteínas/estadística & datos numéricos , Sesgo de Selección , Técnicas del Sistema de Dos Híbridos/estadística & datos numéricosRESUMEN
UNLABELLED: A web applet for browsing protein-protein interactions was implemented. It enables the display of interaction relationships, based upon neighboring distance and biological function. AVAILABILITY: The Java applet is available at http://www.charite.de/bioinformatics