title: Oxidative stress contributes to lung injury and barrier dysfunction via microtubule destabilization.
abstract: Oxidative stress is an important part of host innate immune response to foreign pathogens, such as bacterial LPS, but excessive activation of redox signaling may lead to pathologic endothelial cell (EC) activation and barrier dysfunction. Microtubules (MTs) play an important role in agonist-induced regulation of vascular endothelial permeability, but their impact in modulation of inflammation and EC barrier has not been yet investigated. This study examined the effects of LPS-induced oxidative stress on MT dynamics and the involvement of MTs in the LPS-induced mechanisms of Rho activation, EC permeability, and lung injury. LPS treatment of pulmonary vascular EC induced elevation of reactive oxygen species (ROS) and caused oxidative stress associated with EC hyperpermeability, cytoskeletal remodeling, and formation of paracellular gaps, as well as activation of Rho, p38 stress kinase, and NF-κB signaling, the hallmarks of endothelial barrier dysfunction. LPS also triggered ROS-dependent disassembly of the MT network, leading to activation of MT-dependent signaling. Stabilization of MTs with epothilone B, or inhibition of MT-associated guanine nucleotide exchange factor (GEF)-H1 activity by silencing RNA-mediated knockdown, suppressed LPS-induced EC barrier dysfunction in vitro, and attenuated vascular leak and lung inflammation in vivo. LPS disruptive effects were linked to activation of Rho signaling caused by LPS-induced MT disassembly and release of Rho-specific GEF-H1 from MTs. These studies demonstrate, for the first time, the mechanism of ROS-induced Rho activation via destabilization of MTs and GEF-H1-dependent activation of Rho signaling, leading to pulmonary EC barrier dysfunction and exacerbation of LPS-induced inflammation.
authors: Lung Injury Center, Section of Pulmonary and Critical Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA.
authors: Eric
authors: E
authors: Kratzer
authors: Yufeng
authors: Y
authors: Tian
authors: Nicolene
authors: N
authors: Sarich
authors: Tinghuai
authors: T
authors: Wu
authors: Angelo
authors: A
authors: Meliton
authors: Alan
authors: A
authors: Leff
authors: Anna A
authors: AA
authors: Birukova
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D055371:Acute Lung Injury / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002199:Capillary Permeability; D002478:Cells, Cultured; D017097:Electric Impedance; D042783:Endothelial Cells / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D004730:Endothelium, Vascular / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D034261:Epothilones / Q000494:pharmacology; D055785:Gene Knockdown Techniques; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress; D055550:Protein Stability; D011651:Pulmonary Artery / Q000276:immunology / Q000473:pathology / Q000503:physiopathology; D034622:RNA Interference; D064067:Rho Guanine Nucleotide Exchange Factors; D050257:Tubulin Modulators / Q000494:pharmacology
chemical_list: C577356:ARHGEF2 protein, human; D000975:Antioxidants; D034261:Epothilones; D020662:Guanine Nucleotide Exchange Factors; D008070:Lipopolysaccharides; D064067:Rho Guanine Nucleotide Exchange Factors; D050257:Tubulin Modulators; C093788:epothilone B; D000111:Acetylcysteine