STAT1 Attenuates Murine Allergen-Induced Airway Remodeling and Exacerbation by Carbon Nanotubes.
Am J Respir Cell Mol Biol. 2015 Mar 25;
Authors: Thompson EA, Sayers BC, Glista-Baker EE, Shipkowski KA, Ihrie MD, Duke KS, Taylor AJ, Bonner JC
Abstract
Asthma is characterized by a T-helper 2 (Th2) phenotype and by chronic allergen-induced airway inflammation (AAI). Environmental exposure to air pollution ultrafine particles (i.e., nanoparticles) exacerbates AAI and a concern is possible exacerbation posed by engineered nanoparticles generated by emerging nanotechnologies. STAT1 is a transcription factor that maintains Th1 cell development. However, the role of STAT1 in regulating AAI or exacerbation by nanoparticles has not been explored. In this study, mice with whole body knock-out of the Stat1 gene (Stat1-/-) or wild type (WT) mice were sensitized to ovalbumin (OVA) allergen and then exposed to multi-walled carbon nanotubes (MWCNTs) by oropharygneal aspiration. In Stat1-/- and WT mice, OVA increased eosinophils in bronchoalveolar lavage fluid (BALF), while MWCNTs increased neutrophils. Interestingly, OVA sensitization prevented MWCNT-induced neutrophilia and caused only eosinophilic inflammation. Stat1-/- mice displayed increased IL-13 in BALF 1 day compared to WT mice after treatment with OVA or OVA and MWCNT. At 21 days the lungs of OVA-sensitized Stat1-/- mice displayed increased eosinophilia, goblet cell hyperplasia, airway fibrosis, and subepithelial apoptosis. MWCNTs further increased OVA-induced goblet cell hyperplasia, airway fibrosis, and apoptosis in Stat1-/- mice at 21 days. These changes corresponded to increased levels of pro-fibrogenic mediators (TGF-?1, TNF-?, OPN) but decreased IL-10 in Stat1-/- mice. Finally, fibroblasts isolated from the lungs of Stat1-/- mice produced significantly more collagen mRNA and protein in response to TGF-?1 compared to WT lung fibroblasts. Our results support a protective role for STAT1 in chronic AAI and exacerbation of remodeling caused by MWCNTs.
PMID: 25807359 [PubMed – as supplied by publisher]
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