title: Peroxiredoxin 6 fails to limit phospholipid peroxidation in lung from Cftr-knockout mice subjected to oxidative challenge.
abstract: Oxidative stress plays a prominent role in the pathophysiology of cystic fibrosis (CF). Despite the presence of oxidative stress markers and a decreased antioxidant capacity in CF airway lining fluid, few studies have focused on the oxidant/antioxidant balance in CF cells. The aim of the current study was to investigate the cellular levels of reactive oxygen species (ROS), oxidative damage and enzymatic antioxidant defenses in the lung of Cftr-knockout mice in basal conditions and as a response to oxidative insult.The results show that endogenous ROS and lipid peroxidation levels are higher in Cftr(-/-) lung when compared to wild-type (Cftr(+/+)) in basal conditions, despite a strong enzymatic antioxidant response involving superoxide dismutases, glutathione peroxidases and peroxiredoxin 6 (Prdx6). The latter has the unique capacity to directly reduce membrane phospholipid hydroperoxides (PL-OOH). A dramatic increase in PL-OOH levels in Cftr(-/-) lung consecutive to in vivo oxidative challenge by paraquat (PQ) unmasks a susceptibility to phospholipid peroxidation. PQ strongly decreases Prdx6 expression in Cftr(-/-) mice compared to Cftr(+/+). Similar results were obtained after P. aeruginosa LPS challenge. Two-dimensional gel analysis of Prdx6 revealed one main molecular form in basal conditions and a PQ-induced form only detected in Cftr(+/+) lung. Mass spectrometry experiments suggested that, as opposed to the main basal form, the one induced by PQ is devoid of overoxidized catalytic Cys47 and could correspond to a fully active form that is not induced in Cftr(-/-) lung. These results highlight a constitutive redox imbalance and a vulnerability to oxidative insult in Cftr(-/-) lung and present Prdx6 as a key component in CF antioxidant failure. This impaired PL-OOH detoxification mechanism may enhance oxidative damage and stress-related signaling, contributing to an exaggerated inflammatory response in CF lung.
authors: INSERM, U845, Université Paris Descartes, Faculté de Médecine, Paris, France.
authors: Stéphanie
authors: S
authors: Trudel
authors: Mairead
authors: M
authors: Kelly
authors: Janine
authors: J
authors: Fritsch
authors: Thao
authors: T
authors: Nguyen-Khoa
authors: Patrice
authors: P
authors: Thérond
authors: Martine
authors: M
authors: Couturier
authors: Michal
authors: M
authors: Dadlez
authors: Janusz
authors: J
authors: Debski
authors: Lhousseine
authors: L
authors: Touqui
authors: Benoit
authors: B
authors: Vallée
authors: Mario
authors: M
authors: Ollero
authors: Aleksander
authors: A
authors: Edelman
authors: Franck
authors: F
authors: Brouillard
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002384:Catalysis; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics*; D007249:Inflammation; D008070:Lipopolysaccharides / Q000378:metabolism; D008168:Lung / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016877:Oxidants / Q000378:metabolism; D018384:Oxidative Stress; D054465:Peroxiredoxin VI / Q000378:metabolism / Q000502:physiology*; D010743:Phospholipids / Q000378:metabolism*; D017382:Reactive Oxygen Species; D015398:Signal Transduction
chemical_list: D000975:Antioxidants; D008070:Lipopolysaccharides; D016877:Oxidants; D010743:Phospholipids; D017382:Reactive Oxygen Species; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D054465:Peroxiredoxin VI