RESUMEN
AIMS: We aimed to provide reference values for speckle-tracking derived systolic and diastolic myocardial deformation markers, and to determine their relation with age, sex, and cardiovascular risk factors. METHODS AND RESULTS: The Characteristics and Course of Heart Failure STAges A/B and Determinants of Progression (STAAB) cohort study recruited a representative sample of the population of Würzburg, Germany, aged 30-79 years. In a sample of 1818 participants (52% female, mean age 54±12 years) global longitudinal peak systolic strain (GL-PSS, n = 1218), systolic (GL-SSR, n = 1506), and early (GL-EDSR, n = 1506) and late diastolic strain rates (GL-LDSR, n = 1500) were derived from 2D speckle tracking analysis. From a subgroup of 323 individuals without any cardiovascular risk factor, sex- and age-specific reference values were computed. GL-PSS, GL-SSR, and GL-EDSR were associated with sex, GL-EDSR decreased and GL-LDSR increased with age. In the total sample, dyslipidemia was associated with altered GL-PSS, GL-SSR, and GL-EDSR in women but not in men, whereas obesity was associated with less favorable GL-PSS and GL-EDSR in either sex. Hypertension impacted more adversely on systolic and diastolic myocardial deformation in women compared to men (all p<0.01). CONCLUSION: The female myocardium appeared more vulnerable to high blood pressure and dyslipidemia when compared to men, while obesity was associated with adverse myocardial deformation in either sex. The reference values for echocardiographic myocardial deformation provided for a non-diseased population and their here reported associations with cardiovascular risk factors will inform future observational and intervention studies regarding i) effect sizes and power calculation, ii) cross-study comparisons, and iii) categorization of myocardial deformation in specific patient groups.
Asunto(s)
Enfermedades Cardiovasculares/diagnóstico por imagen , Dislipidemias/epidemiología , Ecocardiografía/métodos , Hipertensión/epidemiología , Obesidad/epidemiología , Adulto , Anciano , Enfermedades Cardiovasculares/etiología , Estudios de Casos y Controles , Dislipidemias/complicaciones , Femenino , Alemania/epidemiología , Humanos , Hipertensión/complicaciones , Masculino , Persona de Mediana Edad , Obesidad/complicaciones , Estudios Prospectivos , Valores de Referencia , Medición de Riesgo , Factores de RiesgoRESUMEN
In a search for sweet taste receptor interacting proteins, we have identified the calcium- and integrin-binding protein 1 (CIB1) as specific binding partner of the intracellular carboxyterminal domain of the rat sweet taste receptor subunit Tas1r2. In heterologous human embryonic kidney 293 (HEK293) cells, the G protein chimeras Galpha(16gust44) and Galpha(15i3) link the sweet taste receptor dimer TAS1R2/TAS1R3 to an inositol 1,4,5-trisphosphate (InsP3)-dependent Ca2+ release pathway. To demonstrate the influence of CIB1 on the cytosolic Ca2+ concentration, we used sweet and umami compounds as well as other InsP3-generating ligands in FURA-2-based Ca2+ assays in wild-type HEK293 cells and HEK293 cells expressing functional human sweet and umami taste receptor dimers. Stable and transient depletion of CIB1 by short-hairpin RNA increased the Ca2+ response of HEK293 cells to the InsP3-generating ligands ATP, UTP and carbachol. Over-expression of CIB1 had the opposite effect as shown for the sweet ligand saccharin, the umami receptor ligand monosodium glutamate and UTP. The CIB1 effect was dependent on the thapsigargin-sensitive Ca2+ store of the endoplasmic reticulum (ER) and independent of extracellular Ca2+. The function of CIB1 on InsP3-evoked Ca2+ release from the ER is most likely mediated by its interaction with the InsP3 receptor. Thus, CIB1 seems to be an inhibitor of InsP3-dependent Ca2+ release in vivo.
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Señalización del Calcio/genética , Proteínas de Unión al Calcio/metabolismo , Calcio/metabolismo , Inositol 1,4,5-Trifosfato/metabolismo , Papilas Gustativas/metabolismo , Gusto/genética , Adenosina Trifosfato/metabolismo , Adenosina Trifosfato/farmacología , Animales , Señalización del Calcio/efectos de los fármacos , Proteínas de Unión al Calcio/genética , Carbacol/farmacología , Línea Celular , Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/genética , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/metabolismo , Inhibidores Enzimáticos/farmacología , Fura-2 , Humanos , Indicadores y Reactivos , Receptores de Inositol 1,4,5-Trifosfato/efectos de los fármacos , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Ligandos , Interferencia de ARN , Ratas , Células Receptoras Sensoriales/efectos de los fármacos , Células Receptoras Sensoriales/fisiología , Gusto/efectos de los fármacos , Papilas Gustativas/efectos de los fármacos , Lengua/metabolismo , Uridina Trifosfato/metabolismo , Uridina Trifosfato/farmacologíaRESUMEN
GPRC6A is a novel member of family C of G protein-coupled receptors with so far elusive biological function. GPRC6A has been described in human and mouse as a promiscuous l-alpha-amino acid receptor. We now report the cloning, expression analysis and, functional characterization of the rat orthologue of GPRC6A. Full-length cloning of rat GPRC6A (rGPRC6A) was accomplished using amplification of cDNA from taste tissue, and the identity of rGPRC6A confirmed at both the genomic and the protein level by similarity studies. Using selective primers, reverse transcriptase polymerase chain reaction showed that the mRNA is widely but weakly distributed, except for a high expression in the soft palate, the so-called geschmacksstreifen. On the protein level, rGPRC6A was shown to be glycosylated and most likely oligomeric, and using immunochemistry we observed that rGPRC6A is expressed at the plasma membrane of mammalian cell lines. Utilizing co-expression of rGPRC6A and the promiscuous Galpha(q)(G66D) protein in an engineered cell-based inositol phosphate turnover assay, we were able to study the ligand profile of the receptor. We found that l-ornithine is the most potent and efficacious l-amino acid agonist with an EC(50) value of 264 microM, followed by several other aliphatic, neutral, and basic amino acids. Furthermore, the divalent cation Mg(2+) was found to be a positive modulator of the l-ornithine response. The presented quantitative pharmacological data underlines the evolutionary conservation of GPRC6A to the rat and signifies the physiological importance and emerging pharmacological potential of GPRC6A.
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Clonación Molecular , Receptores Acoplados a Proteínas G/genética , Animales , Cationes , Línea Celular , Membrana Celular/metabolismo , Bases de Datos de Proteínas , Glicosilación , Humanos , Magnesio/química , Ornitina/química , Paladar Blando/metabolismo , ARN Mensajero/metabolismo , Ratas , Receptores Acoplados a Proteínas G/fisiología , Distribución TisularRESUMEN
Hepatobiliary elimination of many organic anions is initiated by OATP1B1 (OATP2, LST-1, OATP-C), OATP1B3 (OATP8), and OATP2B1 (OATP-B), which are the predominant uptake transporters of human hepatocytes. Thereafter, the unidirectional efflux pump ABCC2 (multidrug resistance protein 2) mediates the transport of organic anions, including glutathione conjugates and glucuronosides, into bile. In this study, we generated a Madin-Darby canine kidney (MDCKII) cell line stably expressing recombinant OATP1B1, OATP1B3, and OATP2B1 in the basolateral membrane and ABCC2 in the apical membrane. Double-transfected MDCKII cells stably expressing ABCC2 together with OATP1B1, OATP1B3, or OATP2B1 served as control cells. The quadruple-transfected cells exhibited high rates of vectorial transport of organic anions, including bromosulfophthalein, cholecystokinin peptide (CCK-8), and estrone 3-sulfate. The quadruple-transfected cells enabled the identification of substrates for uptake or vectorial transport that may be missed in studies with a double-transfected cell line, as exemplified by CCK-8, which is a substrate for OATP1B3 but not for OATP1B1 or OATP2B1. The broad substrate spectrum covered by the three hepatocellular OATP transporters enables representative analyses of the uptake of many organic anions into human hepatocytes. The broad spectrum of organic anions transported vectorially by the quadruple-transfected cells also provides valuable information on the substrate selectivity of ABCC2, without the need for studies in inside-out membrane vesicles containing the ABCC2 protein. The quadruple-transfected MDCKII-ABCC2/OATP1B1/1B3/2B1 cells may thus be useful for the identification of substrates and inhibitors, including drug candidates, undergoing uptake and secretion by human hepatocytes, under conditions that may be better defined than in primary cultures of human hepatocytes.
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Conductos Biliares/metabolismo , Hígado/metabolismo , Transportadores de Anión Orgánico/genética , Secuencia de Aminoácidos , Animales , Aniones , Línea Celular , Perros , Humanos , Transporte Iónico , Datos de Secuencia Molecular , Proteína 2 Asociada a Resistencia a Múltiples Medicamentos , Transportadores de Anión Orgánico/química , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , TransfecciónRESUMEN
Responses of concentrations of usnic (UA) and perlatolic (PA) acids and the relative growth rate (RGR) of a mat-forming lichen, Cladina stellaris, to enhanced N and P input were studied in a fertilisation experiment. It was predicted on the basis of carbon-nutrient balance (CNB) hypothesis that the concentrations of these phenolics would decline and the growth rate increase in response to increased nutrient uptake. The concentration of UA showed a convex response pattern to increased N input whereas the concentration of PA was non-responsive. An ecologically realistic, "moderate", N treatment clearly lowered the level of UA both with and without the P application. Applying P alone caused a significant increase in the level of UA. The RGR of C. stellaris did not respond to nutrient addition. The results indicate that even though the CNB hypothesis may be applicable in explaining concentrations of lichen secondary metabolites, it may be applied under a relatively narrow set of conditions. Especially inherited constraints in the growth of lichen fungi may seriously limit the responsiveness of lichens to short-time changes in the availability of resources. These limitations may also apply to other perennials adapted to nutrient-poor conditions.
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Antifúngicos/análisis , Benzofuranos/análisis , Hidroxibenzoatos/análisis , Líquenes/crecimiento & desarrollo , Líquenes/química , Nitrógeno/farmacología , Fósforo/farmacologíaRESUMEN
BACKGROUND: Despite their strong binding to albumin while circulating in blood, many organic anions, such as bilirubin and fatty acids, are removed efficiently by the liver. The uptake transporters of human hepatocytes, OATP2 (symbol, SLC21A6) and OATP8 (SLC21A8), play important roles in the hepatic uptake of endogenous substances and drugs. The two transporters show different affinities for the organic anion sulfobromophthalein (BSP), which binds with high affinity to albumin in blood. METHODS: In this study, we investigated whether a direct interaction of albumin with OATP2 or OATP8 occurs during the uptake of BSP. The uptake of BSP, at varying concentrations of human serum albumin (HSA), into transfected HEK293 cells expressing recombinant human OATP2 or OATP8 was measured. The influence of other organic anions on the uptake of albumin-bound BSP by OATP2 or OATP8 was also studied. RESULTS: OATP8-mediated transport was affected more strongly by HSA than OATP2-mediated transport. Albumin affected both transporters in the manner of a noncompetitive inhibitor. Uptake studies using OATP2-transfected MDCKII cells indicated that a direct interaction between albumin and OATP2 is not necessary for uptake, a finding that was further confirmed by the effects of bilirubin and palmitate on the binding of BSP to albumin and on the uptake of BSP by OATP2 or OATP8. CONCLUSIONS: Our results indicated that uptake of albumin-bound BSP occurs only from the pool of unbound ligand.