BACKGROUND: Environmental exposure to endotoxin is a known cause of exacerbation of asthma. Inhaled endotoxin protocols have been used to evaluate airway cell surface phenotypes associated with antigen presentation and innate immunity in healthy volunteers, but not in allergic volunteers. OBJECTIVES: To establish the safety of challenge with low-dose endotoxin (10,000 endotoxin units) (lipopolysaccharide [LPS]) inhalation in allergic individuals, to measure airway cell surface phenotypes associated with antigen presentation and innate immunity in induced sputum (IS) after LPS challenge, and to conduct gene expression profiling in IS cells to determine which host genetic networks are modified by LPS inhalation. METHODS: Induced sputum was obtained before and 6 hours after LPS inhalation in 10 allergic volunteers (8 with asthma and 2 with rhinitis). Flow cytometry was used to examine cell surface phenotypes on IS cells. Genomic expression was analyzed on a subset of IS samples (n = 10) using microarray and ingenuity pathway analysis. RESULTS: A total of 10,000 endotoxin units of LPS induced significant up-regulation of membrane CD14, CD11b, CD16, HLA-DR, CD86, and Fcepsilon receptor 1 on sputum phagocytes and increased expression of genes that influence antigen-presenting surface molecules (HLA-DR, chemokine ligand 2 or monocyte chemoattractant protein 1, v-rel reticuloendotheliosis viral oncogene homolog, prostaglandin-endoperoxide synthase 2 or cyclooxygenase 2, and transforming growth factor beta), immune activation (CD14, interleukin 1beta, and regulated upon activation, normal T cell expressed and secreted), and inflammation (intracellular adhesion molecule 1 and inhibitory kappaBalpha). Gene profiles for nuclear factor kappaB, interleukin 1, and tumor necrosis factor pathways were also significantly affected. CONCLUSIONS: Low-dose inhaled endotoxin challenge is safe in allergic individuals with mild to moderate disease. It enhances airway cell surface phenotypes and expression of genes associated with antigen presentation, innate immunity, and inflammation. Microarray with ingenuity pathway analysis can be successfully applied to sputum cells to characterize genetic responses to inhaled exacerbants.
BACKGROUND: Environmental exposure to endotoxin is a known cause of exacerbation of asthma. Inhaled endotoxin protocols have been used to evaluate airway cell surface phenotypes associated with antigen presentation and innate immunity in healthy volunteers, but not in allergic volunteers. OBJECTIVES: To establish the safety of challenge with low-dose endotoxin (10,000 endotoxin units) (lipopolysaccharide [LPS]) inhalation in allergic individuals, to measure airway cell surface phenotypes associated with antigen presentation and innate immunity in induced sputum (IS) after LPS challenge, and to conduct gene expression profiling in IS cells to determine which host genetic networks are modified by LPS inhalation. METHODS: Induced sputum was obtained before and 6 hours after LPS inhalation in 10 allergic volunteers (8 with asthma and 2 with rhinitis). Flow cytometry was used to examine cell surface phenotypes on IS cells. Genomic expression was analyzed on a subset of IS samples (n = 10) using microarray and ingenuity pathway analysis. RESULTS: A total of 10,000 endotoxin units of LPS induced significant up-regulation of membrane CD14, CD11b, CD16, HLA-DR, CD86, and Fcepsilon receptor 1 on sputum phagocytes and increased expression of genes that influence antigen-presenting surface molecules (HLA-DR, chemokine ligand 2 or monocyte chemoattractant protein 1, v-rel reticuloendotheliosis viral oncogene homolog, prostaglandin-endoperoxide synthase 2 or cyclooxygenase 2, and transforming growth factor beta), immune activation (CD14, interleukin 1beta, and regulated upon activation, normal T cell expressed and secreted), and inflammation (intracellular adhesion molecule 1 and inhibitory kappaBalpha). Gene profiles for nuclear factor kappaB, interleukin 1, and tumor necrosis factor pathways were also significantly affected. CONCLUSIONS: Low-dose inhaled endotoxin challenge is safe in allergic individuals with mild to moderate disease. It enhances airway cell surface phenotypes and expression of genes associated with antigen presentation, innate immunity, and inflammation. Microarray with ingenuity pathway analysis can be successfully applied to sputum cells to characterize genetic responses to inhaled exacerbants.
Authors: Michelle L Hernandez; Margaret Herbst; John C Lay; Neil E Alexis; Willie June Brickey; Jenny P Y Ting; Haibo Zhou; David B Peden Journal: J Allergy Clin Immunol Date: 2012-07-04 Impact factor: 10.793
Authors: William D Bennett; Neil E Alexis; Martha Almond; Margaret Herbst; Kirby L Zeman; David B Peden Journal: J Aerosol Med Pulm Drug Deliv Date: 2014-12 Impact factor: 2.849
Authors: Neil E Alexis; John C Lay; Milan Hazucha; Bradford Harris; Michelle L Hernandez; Philip A Bromberg; Howard Kehrl; David Diaz-Sanchez; Chong Kim; Robert B Devlin; David B Peden Journal: Inhal Toxicol Date: 2010-06 Impact factor: 2.724
Authors: Willie June Brickey; Neil E Alexis; Michelle L Hernandez; William Reed; Jenny P Y Ting; David B Peden Journal: J Allergy Clin Immunol Date: 2011-08-25 Impact factor: 10.793
Authors: Michelle Hernandez; Willie June Brickey; Neil E Alexis; Rebecca C Fry; Julia E Rager; Baiming Zhou; Jenny P Y Ting; Haibo Zhou; David B Peden Journal: J Allergy Clin Immunol Date: 2012-01 Impact factor: 10.793
Authors: Michelle L Hernandez; James G Wagner; Aline Kala; Katherine Mills; Heather B Wells; Neil E Alexis; John C Lay; Qing Jiang; Hongtao Zhang; Haibo Zhou; David B Peden Journal: Free Radic Biol Med Date: 2013-02-09 Impact factor: 7.376
Authors: Michelle L Hernandez; Katherine Mills; Martha Almond; Krista Todoric; Maria M Aleman; Hongtao Zhang; Haibo Zhou; David B Peden Journal: J Allergy Clin Immunol Date: 2014-09-05 Impact factor: 10.793