Your browser doesn't support javascript.
loading
Defining the reducing system of the NO dioxygenase cytoglobin in vascular smooth muscle cells and its critical role in regulating cellular NO decay.
Ilangovan, Govindasamy; Khaleel, Sahar A; Kundu, Tapan; Hemann, Craig; El-Mahdy, Mohamed A; Zweier, Jay L.
Afiliación
  • Ilangovan G; Department of Internal Medicine, Division of Cardiovascular Medicine, and the EPR Center, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA.
  • Khaleel SA; Department of Internal Medicine, Division of Cardiovascular Medicine, and the EPR Center, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA; Department of Pharmacology and Toxicology, College of Pharmacy, Al-Azhar University, Cairo, Egypt.
  • Kundu T; Department of Internal Medicine, Division of Cardiovascular Medicine, and the EPR Center, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA.
  • Hemann C; Department of Internal Medicine, Division of Cardiovascular Medicine, and the EPR Center, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA.
  • El-Mahdy MA; Department of Internal Medicine, Division of Cardiovascular Medicine, and the EPR Center, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA.
  • Zweier JL; Department of Internal Medicine, Division of Cardiovascular Medicine, and the EPR Center, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA. Electronic address: jay.zweier@osumc.edu.
J Biol Chem ; 296: 100196, 2021.
Article en En | MEDLINE | ID: mdl-33334890
ABSTRACT
In smooth muscle, cytoglobin (Cygb) functions as a potent nitric oxide (NO) dioxygenase and regulates NO metabolism and vascular tone. Major questions remain regarding which cellular reducing systems regulate Cygb-mediated NO metabolism. To better define the Cygb-mediated NO dioxygenation process in vascular smooth muscle cells (SMCs), and the requisite reducing systems that regulate cellular NO decay, we assessed the intracellular concentrations of Cygb and its putative reducing systems and examined their roles in the process of NO decay. Cygb and the reducing systems, cytochrome b5 (B5)/cytochrome b5 reductase (B5R) and cytochrome P450 reductase (CPR) were measured in aortic SMCs. Intracellular Cygb concentration was estimated as 3.5 µM, while B5R, B5, and CPR were 0.88, 0.38, and 0.15 µM, respectively. NO decay in SMCs was measured following bolus addition of NO to air-equilibrated cells. siRNA-mediated knockdown experiments indicated that âˆ¼78% of NO metabolism in SMCs is Cygb-dependent. Of this, ∼87% was B5R- and B5-dependent. CPR knockdown resulted in a small decrease in the NO dioxygenation rate (VNO), while depletion of ascorbate had no effect. Kinetic analysis of VNO for the B5/B5R/Cygb system with variation of B5 or B5R concentrations from their SMC levels showed that VNO exhibits apparent Michaelis-Menten behavior for B5 and B5R. In contrast, linear variation was seen with change in Cygb concentration. Overall, B5/B5R was demonstrated to be the major reducing system supporting Cygb-mediated NO metabolism in SMCs with changes in cellular B5/B5R levels modulating the process of NO decay.
Asunto(s)
Palabras clave

Texto completo: 1 Banco de datos: MEDLINE Asunto principal: Oxigenasas / Citocromos b5 / Citoglobina / Músculo Liso Vascular / Óxido Nítrico Límite: Animals / Humans Idioma: En Año: 2021 Tipo del documento: Article

Texto completo: 1 Banco de datos: MEDLINE Asunto principal: Oxigenasas / Citocromos b5 / Citoglobina / Músculo Liso Vascular / Óxido Nítrico Límite: Animals / Humans Idioma: En Año: 2021 Tipo del documento: Article