title: Hyperoxia-induced p47phox activation and ROS generation is mediated through S1P transporter Spns2, and S1P/S1P1&2 signaling axis in lung endothelium.
abstract: Hyperoxia-induced lung injury adversely affects ICU patients and neonates on ventilator assisted breathing. The underlying culprit appears to be reactive oxygen species (ROS)-induced lung damage. The major contributor of hyperoxia-induced ROS is activation of the multiprotein enzyme complex NADPH oxidase. Sphingosine-1-phosphate (S1P) signaling is known to be involved in hyperoxia-mediated ROS generation; however, the mechanism(s) of S1P-induced NADPH oxidase activation is unclear. Here, we investigated various steps in the S1P signaling pathway mediating ROS production in response to hyperoxia in lung endothelium. Of the two closely related sphingosine kinases (SphKs)1 and 2, which synthesize S1P from sphingosine, only Sphk1(-/-) mice conferred protection against hyperoxia-induced lung injury. S1P is metabolized predominantly by S1P lyase and partial deletion of Sgpl1 (Sgpl1(+/-)) in mice accentuated lung injury. Hyperoxia stimulated S1P accumulation in human lung microvascular endothelial cells (HLMVECs), and downregulation of S1P transporter spinster homolog 2 (Spns2) or S1P receptors S1P1&2, but not S1P3, using specific siRNA attenuated hyperoxia-induced p47(phox) translocation to cell periphery and ROS generation in HLMVECs. These results suggest a role for Spns2 and S1P1&2 in hyperoxia-mediated ROS generation. In addition, p47(phox) (phox:phagocyte oxidase) activation and ROS generation was also reduced by PF543, a specific SphK1 inhibitor in HLMVECs. Our data indicate a novel role for Spns2 and S1P1&2 in the activation of p47(phox) and production of ROS involved in hyperoxia-mediated lung injury in neonatal and adult mice.
authors.affiliation: Department of Pediatrics, National Jewish Health, Denver, Colorado; Department of Pharmacology, National Jewish Health, Denver, Colorado; harijith@uic.edu.
authors.forename: Anantha
authors.initials: A
authors.lastname: Harijith
authors.affiliation: Department of Pharmacology, National Jewish Health, Denver, Colorado;
authors.forename: Srikanth
authors.initials: S
authors.lastname: Pendyala
authors.affiliation: Department of Biochemistry & Molecular Genetics, National Jewish Health, Denver, Colorado;
authors.forename: David L
authors.initials: DL
authors.lastname: Ebenezer
authors.affiliation: Department of Pediatrics, National Jewish Health, Denver, Colorado;
authors.forename: Alison W
authors.initials: AW
authors.lastname: Ha
authors.affiliation: Department of Pharmacology, National Jewish Health, Denver, Colorado;
authors.forename: Panfeng
authors.initials: P
authors.lastname: Fu
authors.affiliation: Department of Medicinal Chemistry, National Jewish Health, Denver, Colorado;
authors.forename: Yue-Ting
authors.initials: YT
authors.lastname: Wang
authors.affiliation: Department of Pathology, National Jewish Health, Denver, Colorado;
authors.forename: Ke
authors.initials: K
authors.lastname: Ma
authors.affiliation: Department of Pathology, National Jewish Health, Denver, Colorado;
authors.forename: Peter T
authors.initials: PT
authors.lastname: Toth
authors.affiliation: Department of Medicine, National Jewish Health, Denver, Colorado; and.
authors.forename: Evgeny V
authors.initials: EV
authors.lastname: Berdyshev
authors.affiliation: Department of Pharmacology, National Jewish Health, Denver, Colorado;
authors.forename: Prasad
authors.initials: P
authors.lastname: Kanteti
authors.affiliation: Department of Pharmacology, National Jewish Health, Denver, Colorado; Department of Biochemistry & Molecular Genetics, National Jewish Health, Denver, Colorado; Department of Medicine, University of Illinois at Chicago, Chicago, Illinois.
authors.forename: Viswanathan
authors.initials: V
authors.lastname: Natarajan
mesh_terms: D000446:Aldehyde-Lyases / Q000378:metabolism; D000818:Animals; D027321:Anion Transport Proteins / Q000378:metabolism; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology*; D004730:Endothelium, Vascular / Q000473:pathology; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D018496:Hyperoxia / Q000201:enzymology*; D008168:Lung / Q000098:blood supply; D008246:Lysophospholipids / Q000378:metabolism; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D055806:Microvessels / Q000473:pathology; D019255:NADPH Oxidases / Q000378:metabolism*; D021381:Protein Transport; D017382:Reactive Oxygen Species / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D027321:Anion Transport Proteins; D008246:Lysophospholipids; D017382:Reactive Oxygen Species; C000598727:Spns2 protein, human; C060506:sphingosine 1-phosphate; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D000446:Aldehyde-Lyases; C022649:sphingosine 1-phosphate lyase (aldolase); D013110:Sphingosine
keywords: NADPH oxidase; S1P receptors; p47phox; sphingosine kinase; sphingosine-1-phosphate