Increased AT 1 receptor expression and mRNA in kidney glomeruli of AT 2 receptor gene-disrupted mice

The proposed feedback between angiotensin II AT2 and AT1 receptors prompted us to study AT1 receptor expression in kidneys of male AT2 receptor-gene disrupted mice (agtr2 −/y). In wild-type (agtr2 +/y) mice, AT1 receptor binding and mRNA is abundant in glomeruli, and AT1 receptor binding is also high in the inner stripe of the outer medulla. AT2 receptors are scarce, primarily associated to cortical vascular structures. In agtr2 −/y mice, AT1 receptor binding and mRNA were increased in the kidney glomeruli, and AT1 receptor binding was higher in the rest of the cortex and outer stripe of the outer medulla, but not in its inner stripe, indicating different cellular regulation. Although AT2 receptor expression is very low in male agtr 2 +/y mice, their gene disruption alters AT1 receptor expression. AT1 upregulation alone may explain the AT2 gene-disrupted mice phenotype such as increased blood pressure, higher sensitivity to angiotensin II, and altered renal function. The indirect AT1/AT2 receptor feedback could have clinical significance because AT1antagonists are widely used in medical practice.Fil: Saavedra, Juan M.. National Institute of Mental Health; Estados UnidosFil: Häuser, Walter. National Institute of Mental Health; Estados UnidosFil: Ciuffo, Gladys Maria. National Institute of Mental Health; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Egidy, Giorgia. National Institute of Mental Health; Estados UnidosFil: Hoe, Kwang Lae. National Institute of Mental Health; Estados UnidosFil: Jöhren, Olaf. National Institute of Mental Health; Estados UnidosFil: Sembonmatsu, Takaaki. Vanderbilt University; Estados UnidosFil: Inagami, Tadashi. Vanderbilt University; Estados UnidosFil: Armando, Inés. National Institute of Mental Health; Estados Unido

Production of recombinant enzymes of wide use for research

For biotechnological purposes, protein expression refers to the directed synthesis of large amounts of desired proteins. The aim of the present work was to produce reverse transcriptase Moloney murine Leukaemia Virus retro-transcriptase and Taq DNA polymerase, as bioactive products. In the present paper, we report the preparation of recombinant enzymes, expressed in E. coli strains. The enzymes produced exhibited quite good activity, compared with commercial enzymes, allowing us to replace the last ones for several lab applications. We are reporting changes and modifications to standard protocols described. The standard protocols were modified, i.e. for the purification step of Taq, a temperature dependent procedure was designed. The enzymes produced were used in different applications, such as PCR, RT-PCR, PCR Multiplex and RAPDs molecular markers

Production of recombinant enzymes of wide use for research

For biotechnological purposes, protein expression refers to the directed synthesis of large amounts of desired proteins. The aim of the present work was to produce reverse transcriptase Moloney murine Leukaemia Virus retro-transcriptase and Taq DNA polymerase, as bioactive products. In the present paper, we report the preparation of recombinant enzymes, expressed in E. coli strains. The enzymes produced exhibited quite good activity, compared with commercial enzymes, allowing us to replace the last ones for several lab applications. We are reporting changes and modifications to standard protocols described. The standard protocols were modified, i.e. for the purification step of Taq, a temperature dependent procedure was designed. The enzymes produced were used in different applications, such as PCR, RT-PCR, PCR Multiplex and RAPDs molecular markers

Conformational study of Taurine analogues using an empirical atom-atom potential

Taurina es un ß-aminoácido reconocido como neuromodulador. Se realizó un estudio conformacional sobre una serie de análogos estructuralmente relacionados a taurina: L-cisteinsulfínico, homotaurina, ß-alanina, ß-alanina y L-cisteina. Todos ellos se estudiaron en la forma zwitter-iónica, por ser la especie preponderante a pH fisiológico. Para realizar el análisis conformacional se empleó un potencial átomo-átomo empírico. En todos los casos estudiados se obtiene un equilibrio conformacional entre las diferentes conformaciones accesibles, sin encontrar un rotámero predominante. Se hace una discusión comparativa de las semejanzas y diferencias conformacionales y estructurales entre los compuestos estudiados, en función de su diferente actividad biológica. Se considera fundamental para la actividad la presencia de un grupo aniónico en posición ß. Los compuestos activos presentan una importante población en conformaciones con una distancia del orden de los 3 Å entre el grupo amino y el grupo aniónico en posición P. Por otra parte, estos compuestos presentan una gran flexibilidad, que les permitiría adaptarse a los requerimientos del receptorColegio de Farmacéuticos de la Provincia de Buenos Aire

Conformational study of Taurine analogues using an empirical atom-atom potential

Taurina es un ß-aminoácido reconocido como neuromodulador. Se realizó un estudio conformacional sobre una serie de análogos estructuralmente relacionados a taurina: L-cisteinsulfínico, homotaurina, ß-alanina, ß-alanina y L-cisteina. Todos ellos se estudiaron en la forma zwitter-iónica, por ser la especie preponderante a pH fisiológico. Para realizar el análisis conformacional se empleó un potencial átomo-átomo empírico. En todos los casos estudiados se obtiene un equilibrio conformacional entre las diferentes conformaciones accesibles, sin encontrar un rotámero predominante. Se hace una discusión comparativa de las semejanzas y diferencias conformacionales y estructurales entre los compuestos estudiados, en función de su diferente actividad biológica. Se considera fundamental para la actividad la presencia de un grupo aniónico en posición ß. Los compuestos activos presentan una importante población en conformaciones con una distancia del orden de los 3 Å entre el grupo amino y el grupo aniónico en posición P. Por otra parte, estos compuestos presentan una gran flexibilidad, que les permitiría adaptarse a los requerimientos del receptorColegio de Farmacéuticos de la Provincia de Buenos Aire

Neurite outgrowth induced by stimulation of angiotensin II AT2 receptors in SH-SY5Y neuroblastoma cells involves c-Src activation

Neuroblastoma, the most common extracranial solid tumor occurring in childhood, originates from the aberrant proliferation of neural crest cells. Accordingly, the mechanism underling neuronal differentiation could provide new strategies for neuroblastoma treatment. It is well known that neurite outgrowth could be induced by Angiotensin II (Ang II) AT2 receptors; however, the signaling mechanism and its possible interaction with NGF (neural growth factor) receptors remain unclear. Here, we show that Ang II and CGP42112A (AT2 receptor agonist) promote neuronal differentiation by inducing neurite outgrowth and βIII-tubulin expression in SH-SY5Y neuroblastoma cells. In addition, we demonstrate that treatment with PD123319 (AT2 receptor antagonist) reverts Ang II or CGP42112A-induced differentiation. By using specific pharmacological inhibitors we established that neurite outgrowth induced by CGP42112A requires the activation of MEK (mitogen-activated protein kinase kinase), SphK (sphingosine kinase) and c-Src but not PI3K (phosphatidylinositol 3-kinase). Certainly, CGP42112A stimulated a rapid and transient (30 s, 1 min) phosphorylation of c-Src at residue Y416 (indicative of activation), following by a Src deactivation as indicated by phosphorylation of Y527. Moreover, inhibition of the NGF receptor tyrosine kinase A (TrkA) reduced neurite outgrowth induced by Ang II and CGP42112A. In summary, we demonstrated that AT2 receptor-stimulated neurite outgrowth in SH-SY5Y cells involves the induction of MEK, SphK and c-Src and suggests a possible transactivation of TrkA. In that regard, AT2 signaling pathway is a key player in neuronal differentiation and might be a potential target for therapeutic treatments

Structural and electronic properties of tyrosine kinases inhibitors

Protein tyrosine kinases (TKs) regulate cell proliferation, cell differentiation, and play a fundamental role in signal transduction pathway. Uncontrolled signaling from receptor tyrosine kinases and intracellular tyrosine kinases was related to diseases such as cancer, atherosclerosis and psoriasis. For the present study, we selected a number of structurally related ATP-binding site inhibitors of EGF-receptors of diverse classes. Molecular properties of competitive inhibitors are key features for the action mechanism of these compounds. We performed a theoretical study at the RHF/6-311G* level of theory, in order to correlate the molecular parameters with the biological inhibitory activities. Species stability as evaluated by ionization potentials as well as the E(HOMO)-E(LUMO) energy gap, is in very good correlation with higher inhibitory potency (IP). The most active species, 1, 5, 6,10,11 and 12 exhibited strongly negative charged atoms over the C6 and C7 positions, the higher IP, higher mu and higher energy gap. In summary, a good correlation was observed between the molecular parameters, such as ionization potential, dipolar moment and E(HOMO)-E(LUMO) energy gap and inhibitory potency, suggesting that these properties play an important role for the interaction at the ATP-binding site of EGF-receptors.Fil: Santillán, Marta B.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química; ArgentinaFil: Tomas Vert, Francisco. Universidad de Valencia; EspañaFil: Aulló, Josep M.. Universidad de Valencia; EspañaFil: Jauregui, Esteban Adrian. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química; ArgentinaFil: Ciuffo, Gladys Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentin

Production of recombinant enzymes of wide use for research

For biotechnological purposes, protein expression refers to the directed synthesis of large amounts of desired proteins. The aim of the present work was to produce reverse transcriptase Moloney murine Leukaemia Virus retro-transcriptase and Taq DNA polymerase, as bioactive products. In the present paper, we report the preparation of recombinant enzymes, expressed in E. coli strains. The enzymes produced exhibited quite good activity, compared with commercial enzymes, allowing us to replace the last ones for several lab applications. We are reporting changes and modifications to standard protocols described. The standard protocols were modified, i.e. for the purification step of Taq, a temperature dependent procedure was designed. The enzymes produced were used in different applications, such as PCR, RT-PCR, PCR Multiplex and RAPDs molecular markers

Increased AT\u3csub\u3e1\u3c/sub\u3e receptor expression and mRNA in kidney glomeruli of AT\u3csub\u3e2\u3c/sub\u3e receptor gene-disrupted mice

The proposed feedback between angiotensin II AT2 and AT1 receptors prompted us to study AT1 receptor expression in kidneys of male AT2 receptor-gene disrupted mice (agtr2 -/y). In wild-type (agtr2 +/y) mice, AT1 receptor binding and mRNA is abundant in glomeruli, and AT1 receptor binding is also high in the inner stripe of the outer medulla. AT2 receptors are scarce, primarily associated to cortical vascular structures. In agtr2 -/y mice, AT1 receptor binding and mRNA were increased in the kidney glomeruli, and AT1 receptor binding was higher in the rest of the cortex and outer stripe of the outer medulla, but not in its inner stripe, indicating different cellular regulation. Although AT2 receptor expression is very low in male agtr 2 +/y mice, their gene disruption alters AT1 receptor expression. AT1 upregulation alone may explain the AT2 gene-disrupted mice phenotype such as increased blood pressure, higher sensitivity to angiotensin II, and altered renal function. The indirect AT1/AT2 receptor feedback could have clinical significance because AT1 antagonists are widely used in medical practice