title: Proteases and oxidant stress control organic dust induction of inflammatory gene expression in lung epithelial cells.
abstract: Persistant inflammatory responses to infectious agents and other components in organic dust underlie lung injury and development of respiratory diseases. Organic dust components responsible for eliciting inflammation and the mechanisms by which they cause lung inflammation are not fully understood. We studied the mechanisms by which protease activities in poultry dust extracts and intracellular oxidant stress induce inflammatory gene expression in A549 and Beas2B lung epithelial cells.
  
  
  
  The effects of dust extracts on inflammatory gene expression were analyzed by quantitative polymerase chain reaction (qPCR), enzyme linked immunosorbent (ELISA) and western blot assays. Oxidant stress was probed by dihydroethidium (DHE) labeling, and immunostaining for 4-hydroxynonenal (4-HNE). Effects on interleukin-8 (IL-8) promoter regulation were determined by transient transfection assay.
  
  
  
  Dust extracts contained trypsin and elastase activities, and activated protease activated receptor (PAR)-1 and -2. Serine protease inhibitors and PAR-1 or PAR-2 knockdown suppressed inflammatory gene induction. Dust extract induction of IL-8 gene expression was associated with increased DHE-fluorescence and 4-HNE staining, and antioxidants suppressed inflammatory gene induction. Protease inhibitors and antioxidants suppressed protein kinase C and NF-κB activation and induction of IL-8 promoter activity in cells exposed to dust extract.
  
  
  
  Our studies demonstrate that proteases and intracellular oxidants control organic dust induction of inflammatory gene expression in lung epithelial cells. Targeting proteases and oxidant stress may serve as novel approaches for the treatment of organic dust induced lung diseases. This is the first report on the involvement of oxidant stress in the induction of inflammatory gene expression by organic dust.
authors: Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, 11937 US Highway 271, Tyler, TX, 75708-3154, USA.
authors: Kartiga
authors: K
authors: Natarajan
authors: Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, 11937 US Highway 271, Tyler, TX, 75708-3154, USA.
authors: Koteswara R
authors: KR
authors: Gottipati
authors: Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, 11937 US Highway 271, Tyler, TX, 75708-3154, USA.
authors: Kiflu
authors: K
authors: Berhane
authors: Department of Pulmonary Immunology, University of Texas Health Science Center at Tyler, Tyler, TX, USA.
authors: Buka
authors: B
authors: Samten
authors: Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, 11937 US Highway 271, Tyler, TX, 75708-3154, USA.
authors: Usha
authors: U
authors: Pendurthi
authors: Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, 11937 US Highway 271, Tyler, TX, 75708-3154, USA. vijay.boggaram@uthct.edu.
authors: Vijay
authors: V
authors: Boggaram
mesh_terms: D000072283:A549 Cells; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D004391:Dust; D004847:Epithelial Cells / Q000187:drug effects* / Q000201:enzymology; D005786:Gene Expression Regulation; D006799:Housing, Animal; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D019570:Inhalation Exposure / Q000009:adverse effects; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism; D008168:Lung / Q000187:drug effects* / Q000201:enzymology; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000378:metabolism; D009930:Organic Chemicals / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects*; D010447:Peptide Hydrolases / Q000378:metabolism*; D011014:Pneumonia / Q000139:chemically induced* / Q000201:enzymology / Q000235:genetics / Q000517:prevention & control; D011200:Poultry; D044463:Receptor, PAR-1 / Q000235:genetics / Q000378:metabolism; D044464:Receptor, PAR-2 / Q000235:genetics / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014162:Transfection
chemical_list: D000893:Anti-Inflammatory Agents; D000975:Antioxidants; C508606:CXCL8 protein, human; D004391:Dust; D018836:Inflammation Mediators; D016209:Interleukin-8; D009930:Organic Chemicals; D044463:Receptor, PAR-1; D044464:Receptor, PAR-2; D015842:Serine Proteinase Inhibitors; D010447:Peptide Hydrolases; D020782:Matrix Metalloproteinases
keywords: Gene expression; Lung epithelial cells; Oxidant stress; Protease; Protease-activated receptors