Selective IκB Kinase Expression in Airway Epithelium Generates Neutrophilic Lung Inflammation

Abstract

To determine whether NF-κB activation is sufficient to generate lung inflammation in vivo, we selectively expressed a constitutively active form of IκB kinase 1 (cIKK1) or IκB kinase 2 (cIKK2) in airway epithelium. After intratracheal administration of adenoviral vectors expressing cIKK1 or cIKK2 to transgenic reporter mice that express Photinus luciferase under the control of an NF-κB-dependent promoter, we detected significantly increased luciferase activity over time (up to 96 h). Compared with control mice treated with adenoviral vectors expressing β-galactosidase, lung bioluminescence and tissue luciferase activity were increased in NF-κB reporter mice treated with adenovirus (Ad)-cIKK1 or Ad-cIKK2. NF-κB activation in lungs of Ad-cIKK1- and Ad-cIKK2-treated mice was confirmed by immunoblots for RelA and EMSA from lung nuclear protein extracts. Mice treated with Ad-cIKK1 or Ad-cIKK2 showed induction of mRNA expression of several chemokines and cytokines in lung tissue. In lung lavage fluid, mice treated with Ad-cIKK1 or Ad-cIKK2 showed elevated concentrations of NF-κB-dependent chemokines macrophage-inflammatory protein 2 and KC and increased numbers of neutrophils. Coadministration of adenoviral vectors expressing a transdominant inhibitor of NF-κB with Ad-cIKK1 or Ad-cIKK2 resulted in abrogated NF-κB activation and other parameters of lung inflammation, demonstrating that the observed inflammatory effects of Ad-cIKK1 and Ad-cIKK2 were dependent on NF-κB activation by these kinases. These data show that selective expression of IκB kinases in airway epithelium results in NF-κB activation, inflammatory mediator production, and neutrophilic lung inflammation. Therapies targeted to NF-κB in lung epithelium may be beneficial in treating inflammatory lung diseases.

Functions and Regulation of NF-κB RelA during Pneumococcal Pneumonia

“…Previous studies manipulating the NF-B pathway using tissue-specific transgenes (20,22), bone marrow chimeras (17,48,49), and adenoviral vectors (19,21) suggest that NF-B activity in epithelial cells is involved in and/or necessary for initiating inflammatory responses elicited by Gram-negative stimuli. We conducted experiments using alveolar/bronchial epithelial-specific SPC-dnI B␣ transgenic mice to complement our findings in mice lacking RelA in all cells.…”

“…Upstream manipulation of the NF-B pathway has also been used as an alternative strategy to RelA deletion. Overexpression of I B kinases in the lungs is sufficient to induce pulmonary inflammation (19), whereas inhibition of NF-B activity in airway epithelium with a dominant-negative (dn) 3 form of I B prevents inflammatory responses to Gram-negative stimuli (20 -22).…”

Airway Epithelial NF-κB Activation Modulates Asbestos-Induced Inflammation and Mucin Production In Vivo

“…NF-B in the airway epithelium has been studied experimentally using adenoviral vectors to induce (35) or inhibit (36) its activity and has also been inhibited using genetic approaches (14,16,37). These studies demonstrate the capacity of airway epithelial NF-B to modulate neutrophilic and eosinophilic inflammatory responses to endotoxin and allergens.…”

Bioluminescence imaging of Smad signaling in living mice shows correlation with excitotoxic neurodegeneration

“…We conclude that Smad2 signaling is a sensitive indicator of CNS injury in this model and can be used to monitor such injury and test potential neuroprotective drugs. Bioluminescence imaging has been used recently for the study of gene expression in transgenic mice that express luciferase reporter genes under control of various promoters or transcription factor binding sites (35)(36)(37)(38). In the brain, bioluminescence has been used mainly to track and quantify luciferase-tagged tumor cells (39)(40)(41)(42) or to trace migration of neural progenitor cells (43,44).…”