Exploring the Role of CYP3A4 Mediated Drug Metabolism in the Pharmacological Modulation of Nitric Oxide Production

Nitric-oxide synthase, the enzyme responsible for mammalian nitric oxide generation, and cytochrome P450, the major enzymes involved in drug metabolism, share striking similarities. Therefore, it makes sense that cytochrome P450 drug mediated biotransformations might play an important role in the pharmacological modulation of nitric oxide synthase. In this work, we have undertaken an integrated in vitro assessment of the hepatic metabolism and nitric oxide modulation of previously described dual inhibitors (imidazoles and macrolides) of these enzymes in order assess the implication of CYP450 activities over production of nitric oxide. In vitro systems based in human liver microsomes and activated mouse macrophages were developed for these purposes. Additionally in vitro production the hepatic metabolites of dual inhibitor, roxithromycin, was investigated achieving the identification and isolation of main hepatic biotransformation products. Our results suggested that for some macrolide compounds, the cytochrome P450 3A4 derived drug metabolites have an important effect on nitric oxide production and might critically contribute to the pharmacological immunomodulatory activity observed.This work was supported by the Spanish Ministry of Economy and Competitivity (SAF2011-29648) and Junta de Andalucía (AGR-6826 and CTS 164) with funds from the European Union; FA is a predoctoral fellow of Junta de Andalucia; MR is a postdoctoral fellow of CIBER-EHD. The CIBEREHD is funded by the Instituto de Salud Carlos III. The MEDINA authors disclosed the receipt of financial support from Fundación MEDINA, a public-private partnership of Merck Sharp and Dohme de España S.A./Universidad de Granada/Junta de Andalucía. In the case of Noemi Vergara Segura, she was a CEIBioTic fellow from the program at the Granada University. The results presented in this work will be compiled in the doctoral thesis (knowledge area code 32089 and subject code 320903) entitled “Evaluación de la actividad de los metabolitos hepáticos derivados de compuestos inmunomodulares e inhibidores de GSK3,” carried out currently by JP at FUNDACIÓN MEDINA in collaboration with the department of Pharmacology at the University of Granada, being the thesis directors, FV (FUNDACIÓN MEDINA) and JG (Universidad de Granada)