title: Protein kinase G increases antioxidant function in lung microvascular endothelial cells by inhibiting the c-Abl tyrosine kinase.
abstract: Oxidant injury contributes to acute lung injury (ALI). We previously reported that activation of protein kinase GI (PKGI) posttranscriptionally increased the key antioxidant enzymes catalase and glutathione peroxidase 1 (Gpx-1) and attenuated oxidant-induced cytotoxicity in mouse lung microvascular endothelial cells (MLMVEC). The present studies tested the hypothesis that the antioxidant effect of PKGI is mediated via inhibition of the c-Abl tyrosine kinase. We found that activation of PKGI with the cGMP analog 8pCPT-cGMP inhibited c-Abl activity and decreased c-Abl expression in wild-type but not PKGI(-/-) MLMVEC. Treatment of wild-type MLMVEC with atrial natriuretic peptide also inhibited c-Abl activation. Moreover, treatment of MLMVEC with the c-Abl inhibitor imatinib increased catalase and GPx-1 protein in a posttranscriptional fashion. In imatinib-treated MLMVEC, there was no additional effect of 8pCPT-cGMP on catalase or GPx-1. The imatinib-induced increase in antioxidant proteins was associated with an increase in extracellular H2O2 scavenging by MLMVEC, attenuation of oxidant-induced endothelial barrier dysfunction, and prevention of oxidant-induced endothelial cell death. Finally, in the isolated perfused lung, imatinib prevented oxidant-induced endothelial toxicity. We conclude that cGMP, through activation of PKGI, inhibits c-Abl, leading to increased key antioxidant enzymes and resistance to lung endothelial oxidant injury. Inhibition of c-Abl by active PKGI may be the downstream mechanism underlying PKGI-mediated antioxidant signaling. Tyrosine kinase inhibitors may represent a novel therapeutic approach in oxidant-induced ALI.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, and.
authors.forename: R Scott
authors.initials: RS
authors.lastname: Stephens
authors.forename: Laura E
authors.initials: LE
authors.lastname: Servinsky
authors.forename: Otgonchimeg
authors.initials: O
authors.lastname: Rentsendorj
authors.forename: Todd M
authors.initials: TM
authors.lastname: Kolb
authors.forename: Alexander
authors.initials: A
authors.lastname: Pfeifer
authors.forename: David B
authors.initials: DB
authors.lastname: Pearse
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000502:physiology; D055371:Acute Lung Injury / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D009320:Atrial Natriuretic Factor / Q000378:metabolism; D001549:Benzamides / Q000494:pharmacology; D002374:Catalase / Q000378:metabolism; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D017869:Cyclic GMP-Dependent Protein Kinases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism; D004789:Enzyme Activation; D005979:Glutathione Peroxidase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D000068877:Imatinib Mesylate; D008168:Lung / Q000166:cytology / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010084:Oxidation-Reduction / Q000187:drug effects; D010879:Piperazines / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D016315:Proto-Oncogene Proteins c-abl / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011743:Pyrimidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D015398:Signal Transduction / Q000187:drug effects; D000094765:Glutathione Peroxidase GPX1
chemical_list: D001549:Benzamides; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D012333:RNA, Messenger; D009320:Atrial Natriuretic Factor; D000068877:Imatinib Mesylate; D006861:Hydrogen Peroxide; D002374:Catalase; D005979:Glutathione Peroxidase; D016315:Proto-Oncogene Proteins c-abl; D017869:Cyclic GMP-Dependent Protein Kinases; D006152:Cyclic GMP; D000094765:Glutathione Peroxidase GPX1; C000722068:Gpx1 protein, mouse
keywords: acute lung injury; c-Abl; endothelium; oxidant injury; protein kinase G