VX-509 (Decernotinib)-Mediated CYP3A Time-Dependent Inhibition: An Aldehyde Oxidase Metabolite as a Perpetrator of Drug-Drug Interactions.

(R)-2-((2-(1H-pyrrolo[2,3-b]pyridin-3-yl)pyrimidin-4-yl)amino)-2-methyl-N-(2,2,2-trifluoroethyl)butanamide (VX-509, decernotinib) is an oral Janus kinase 3 inhibitor that has been studied in patients with rheumatoid arthritis. Patients with rheumatoid arthritis often receive multiple medications, such as statins and steroids, to manage the signs and symptoms of comorbidities, which increases the chances of drug-drug interactions (DDIs). Mechanism-based inhibition is a subset of time-dependent inhibition (TDI) and occurs when a molecule forms a reactive metabolite which irreversibly binds and inactivates drug-metabolizing enzymes, potentially increasing the systemic load to toxic concentrations. Traditionally, perpetrating compounds are screened using human liver microsomes (HLMs); however, this system may be inadequate when the precipitant is activated by a non-cytochrome P450 (P450)-mediated pathway. Even though studies assessing competitive inhibition and TDI using HLM suggested a low risk for CYP3A4-mediated DDI in the clinic, VX-509 increased the area under the curve of midazolam, atorvastatin, and methyl-prednisolone by approximately 12.0-, 2.7-, and 4.3-fold, respectively. Metabolite identification studies using human liver cytosol indicated that VX-509 is converted to an oxidative metabolite, which is the perpetrator of the DDIs observed in the clinic. As opposed to HLM, hepatocytes contain the full complement of drug-metabolizing enzymes and transporters and can be used to assess TDI arising from non-P450-mediated metabolic pathways. In the current study, we highlight the role of aldehyde oxidase in the formation of the hydroxyl-metabolite of VX-509, which is involved in clinically significant TDI-based DDIs and represents an additional example in which a system-dependent prediction of TDI would be evident.

Factores estructurales, bioquímicos y moleculares de la simbiosis Bradyrhizobium sp. (Lupinus)-Lupinus / Structural, biochemical and molecular factors of the simbiosis Bradyrhizobium sp. (Lupinus)-Lupinus

La presente revisión es un resumen de algunos trabajos originales realizados en nuestro Departamento para el estudio de diferentes aspectos de esta peculiar simbiosis, siempre integrando estructura y función. La primera parte está dedicada a un estudio estructural llevado a cabo con el fin de conocer los mecanismos de infección, que difieren de la mayoría de las leguminosas estudiadas. Para este fin se aplicaron técnicas de immunofluorescencia con la green fluorescent protein (GPT), técnicas de inmunocitoquímica y de hibridación in situ. Mediante estos estudios se ha observado que la infección se realiza por vía intercelular. Junto al estudio estructural se describen algunos componentes enzimáticos del nódulo, MAPKinasas (Mitogen-activated protein kinase) y aldehído oxidasa, presentes en estadios tempranos del reconocimiento bacteria-planta. Ambos enzimas están relacionados con la mitosis y la multiplicación de las células radicales. La segunda parte se refiere a los mecanismos fisiológicos, bioquímicos y moleculares que regulan la simbiosis, especialmente los relacionados con la regulación de oxígeno en el nódulo, de gran importancia para la fijación de N2, ya que la nitrogenasa necesita una atmósfera microaeróbica para fijar nitrógeno. Se describen algunos mecanismos de regulación, como la leghemoglobina y la barrera de resistencia a la difusión de O2. Por último también se incluye el estudio genético que realizamos para conocer los genes que regulan la difusión de O2 en el nódulo: lenod 2, leghemoglobin y nifH

The present revision summarises some of the original works carried out in our Department to study different aspects of the peculiar symbiosis Bradyrhyzobium sp. Lupinus, by integrating structure and function. The first part of the revision is focused to a structural study on the infection mechanisms, since differ of other legumes. This study was realized by applying immunofluorescent techniques with the green fluorescent protein, immunocytochemistry and different microscopies. It could be observed that the infection by the Bradyrhizobium follows the intercellular way. The infection study includes the presence of enzymatic components, as MAPKs (Mitogen-Activated Protein Kinase) and aldehyde oxidase in the first steps of the symbiosis. Both enzymes are very much related with auxins and cell multiplication. The second part takes up the physiological, biochemical and genetic mechanisms that regulates nitrogen fixation, speccially those related to oxygen diffusion, since nitrogenase activity is very sensible to oxygen and needs a microaerobic atmosphere for its function. Between these mechanisms, the leghemoglobine and the oxygendiffusion resistance barrier have been considered the more important in oxygen regulation. Finally it is included the results of a genetic study carried out to know the genes implicated in nodule oxygen diffusion as: lenod 2, leghemoglobin and nifH

Aldehyde oxidase and its contribution to the metabolism of a structurally novel, functionally selective GABAA alpha5-subtype inverse agonist.

(3-Tert-butyl-7-(5-methylisoxazol-3-yl)-2-(1-methyl-1H-1,2,4-triazol-5-ylmethoxy)pyrazolo[1,5-d] [1,2,4]triazine was recently identified as a functionally selective, inverse agonist at the benzodiazepine site of GABA(A) alpha5-containing receptors, which enhances performance in animal models of cognition. The routes of metabolism of this compound in rat, dog, rhesus monkey and human in vitro systems, and in vivo in rat, dog and rhesus monkey have been characterized. The current study demonstrates that both a cytosolic oxidative reaction and cytochrome P450 play important roles in the metabolism of the compound. Chemical inhibition studies showed the oxidation in human cytosol to be catalysed predominantly by aldehyde oxidase rather than the related enzyme, xanthine oxidase. The aldehyde oxidase-mediated metabolites were present in vitro and in vivo in both rat and rhesus monkey, and also in vitro in man. They were absent both in vitro and in vivo in dog.

A comparative study on the archives of xanthine oxidase and aldehyde oxidase in different fish species from two rivers in the Western Niger-Delta.

Glycaemia, a classical indicator of stress, xanthine oxidase and aldehyde oxidase which are involved in phase I detoxication were investigated in two different fish species from two rivers with different pollution levels in the Western Niger-Delta. Four sampling zones covering the entire lengths of Warri and Ethiope Rivers respectively were used in this study. For each species of fish five were obtained from a sampling zone in a river. Blood glucose was significantly higher (P < 0.001) in M. electricus from Warri River (82.13 +/- 5.50 mg cm(-3)) compared to the same species from Ethiope River (36.47 +/- 1.49 mg cm(-3)). With the same parameter a similar profile was observed for C. gariepinus; Warri River (56.92 +/- 10.31 mg cm(-3)); Ethiope River (37.65 +/- 0.90 mg cm(-3)) which was also significant (P < 0.01). The activity of xanthine oxidase in M. electricus from Warri River (255.80 +/- 41 it mol cm(-3)) was significantly higher (P < 0.001) compared to the value obtained for the same species (108 +/- 22.36 micro mol cm(-3)) from Ethiope River. Also the activity of xanthine oxidase in C. gariepinus from Warri River (197 +/- 34.65 micro mol cm(-3)) was significantly higher (P < 0.001) when matched with the value obtained for the same species (78.40 +/- 26.84 micro mol cm(-3)) from Ethiope River. That blood glucose level was related to xanthine oxidase activity in the two fish species from Warri River was supported by the high positive correlation between these two parameters (M. electricus. r = 1: C. gariepinus, r = 0.71). The activity of aldehyde oxidase in C. gariepinus from Warri River (143.80 +/- 28.45 micro mol cm(-3)) was significantly higher (P < 0.001) compared to the value obtained for the same species (61.20 +/- 15.21 micro mol cm(-3)) from Ethiope River. A similar profile in aldehyde oxidase activity observed for M. electricus; Warri River (130 +/- 28.39 micro mol cm(-3)); Ethiope River (89 +/- 19.70 micro mol cm(-3)) but an inferior statistical variation (P < 0.05) was obtained. The results obtained in this study indicate that the level of xanthine oxidase in M. electricus is a more specific marker and to a lesser extent its activity in C. gariepinus in monitoring environmental stress due to pollution.