title: Reactive Oxygen Species/Hypoxia-Inducible Factor-1α/Platelet-Derived Growth Factor-BB Autocrine Loop Contributes to Cocaine-Mediated Alveolar Epithelial Barrier Damage.
abstract: Abuse of psychostimulants, such as cocaine, has been shown to be closely associated with complications of the lung, such as pulmonary hypertension, edema, increased inflammation, and infection. However, the mechanism by which cocaine mediates impairment of alveolar epithelial barrier integrity that underlies various pulmonary complications has not been well determined. Herein, we investigate the role of cocaine in disrupting the alveolar epithelial barrier function and the associated signaling cascade. Using the combinatorial electric cell-substrate impedance sensing and FITC-dextran permeability assays, we demonstrated cocaine-mediated disruption of the alveolar epithelial barrier, as evidenced by increased epithelial monolayer permeability with a concomitant loss of the tight junction protein zonula occludens-1 (Zo-1) in both mouse primary alveolar epithelial cells and the alveolar epithelial cell line, L2 cells. To dissect the signaling pathways involved in this process, we demonstrated that cocaine-mediated induction of permeability factors, platelet-derived growth factor (PDGF-BB) and vascular endothelial growth factor, involved reactive oxygen species (ROS)-dependent induction of hypoxia-inducible factor (HIF)-1α. Interestingly, we demonstrated that ROS-dependent induction of another transcription factor, nuclear factor erythroid-2-related factor-2, that did not play a role in cocaine-mediated barrier dysfunction. Importantly, this study identifies, for the first time, that ROS/HIF-1α/PDGF-BB autocrine loop contributes to cocaine-mediated barrier disruption via amplification of oxidative stress and downstream signaling. Corroboration of these cell culture findings in vivo demonstrated increased permeability of the alveolar epithelial barrier, loss of expression of Zo-1, and a concomitantly increased expression of both HIF-1α and PDGF-BB. Pharmacological blocking of HIF-1α significantly abrogated cocaine-mediated loss of Zo-1. Understanding the mechanism(s) by which cocaine mediates barrier dysfunction could provide insights into the development of potential therapeutic targets for cocaine-mediated pulmonary hypertension.
authors.affiliation: 1 School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Yang
authors.affiliation: 2 Department of Emergence, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China; and.
authors.forename: Xufeng
authors.initials: X
authors.lastname: Chen
authors.affiliation: 3 Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Samantha M
authors.initials: SM
authors.lastname: Simet
authors.affiliation: 1 School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.|3 Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Guoku
authors.initials: G
authors.lastname: Hu
authors.affiliation: 3 Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Yu
authors.initials: Y
authors.lastname: Cai
authors.affiliation: 3 Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Fang
authors.initials: F
authors.lastname: Niu
authors.affiliation: 3 Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Yeonhee
authors.initials: Y
authors.lastname: Kook
authors.affiliation: 3 Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska.
authors.forename: Shilpa J
authors.initials: SJ
authors.lastname: Buch
mesh_terms: D056809:Alveolar Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D000818:Animals; D019898:Autocrine Communication; D000077214:Becaplermin; D002463:Cell Membrane Permeability / Q000187:drug effects; D003042:Cocaine / Q000009:adverse effects*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D008810:Mice, Inbred C57BL; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D020574:Proto-Oncogene Proteins c-sis / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D020574:Proto-Oncogene Proteins c-sis; D017382:Reactive Oxygen Species; D042461:Vascular Endothelial Growth Factor A; D000077214:Becaplermin; D003042:Cocaine
keywords: alveolar epithelium; cocaine; hypoxia-inducible factor-1α; platelet-derived growth factor-BB; reactive oxygen species