title: NADPH oxidase-derived ROS: key modulators of heme-induced mitochondrial stability in human neutrophils.
abstract: Heme is a proinflammatory molecule able to cause a profound delay of constitutive apoptosis of human neutrophils, an effect that likely contributes to chronic inflammation associated with hemolytic diseases. Herein we show that heme-induced delay of neutrophil apoptosis correlates with the prevention of mitochondrial potential (Deltapsi(m)) dissipation by a mechanism dependent on NADPH oxidase (NADPHox)-generated reactive oxygen species (ROS) and NF-kappaB. Deltapsi(m) maintenance is accompanied by inhibition of Bax insertion into mitochondria and by a decrease in the Bad/Bcl-X(L) ratio. Heme induces Bad degradation in a completely ROS-dependent manner, as well as Bcl-X(L) synthesis, a phenomenon that also requires NF-kappaB activation. These data indicate that heme-induced preservation of mitochondrial integrity is a critical checkpoint controlled by NADPH oxidase generated-ROS and redox-sensitive NF-kappaB activation.
authors.affiliation: Departamento de Farmacologia, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, Av. 28 de setembro 87-Vila Izabel, Rio de Janeiro, RJ, 20551-030 Brazil.
authors.forename: Maria Augusta
authors.initials: MA
authors.lastname: Arruda
authors.forename: Pedro
authors.initials: P
authors.lastname: Barcellos-de-Souza
authors.forename: André Luiz Franco
authors.initials: AL
authors.lastname: Sampaio
authors.forename: Adriano G
authors.initials: AG
authors.lastname: Rossi
authors.forename: Aurélio V
authors.initials: AV
authors.lastname: Graça-Souza
authors.forename: Christina
authors.initials: C
authors.lastname: Barja-Fidalgo
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D006418:Heme / Q000378:metabolism* / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D019255:NADPH Oxidases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism*; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D051025:bcl-Associated Death Protein / Q000378:metabolism; D051020:bcl-X Protein / Q000378:metabolism
chemical_list: C494819:BAD protein, human; C494826:BAX protein, human; C494811:BCL2L1 protein, human; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D051025:bcl-Associated Death Protein; D051020:bcl-X Protein; D006418:Heme; D019255:NADPH Oxidases