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2624648 
Journal Article 
Abstract 
Calcium mobilization in human airway epithelial cells by an airway disease-relevant extract of hog-barn dust 
Dodmane, PR; Schulte, NA; Romberger, DJ; Toews, ML 
2010 
Yes 
American Journal of Respiratory and Critical Care Medicine
ISSN: 1073-449X
EISSN: 1535-4970 
181 
A6379 
English 
WOS:000208771004738 
is part of a larger document 3452678 Proceedings of the American Thoracic Society 2010 International Conference, May 14-19, 2010, New Orleans
RATIONALE.
Workers in swine confinement facilities are susceptible to development of chronic inflammatory lung disease, but the active components in the dust and the cellular and molecular mechanisms involved in the disease remain poorly defined. An aqueous hog-barn dust extract (HDE) stimulates release of cytokines IL6 and IL8 from cultured BEAS-2B human airway epithelial cells. Because this response involves activation of the Ca^2+-dependent protein kinase C-alpha isozyme, we hypothesized that HDE would stimulate Ca^2+ mobilization in these cells also.

METHODS.
HDE was subjected to gel filtration to separate its components by size, and HDE or fractions were treated with proteinase K to hydrolyze protein components. Intracellular Ca^2+ mobilization in confluent BEAS-2B cells was monitored fluorometrically with a Flex Station Ca^2+-monitoring system.

RESULTS.
HDE caused a concentration-dependent increase in Ca^2+ mobilization that was comparable to that induced by 10 µM lysophosphatidic acid, with half-maximal effects at 0.7% HDE. Gel filtration of HDE on Sephadex G-100 showed two distinct peaks of Ca^2+ mobilizing activity, one with relatively low activity in ~30-50 kDa MW fractions and a broad peak of strong activity in the very low MW fractions eluting near the end of the run. These Ca^2+-mobilizing peaks overlapped with two of the three peaks of IL6- and IL8-releasing activity of HDE identified in separate studies. HDE-induced stimulation of IL6 and IL8 release is reduced but not eliminated by proteinase K treatment of HDE; the larger MW Ca^2+-mobilizing activity was also sensitive to proteinase K, but the low MW activity was not. Complete HDE stimulates rapid phosphorylation of EGF receptors but the Ca^2+-mobilizing fractions did not. The higher MW peak exhibited very slow Ca^2+ elevation (1-2 min) whereas the low MW peak exhibited rapid Ca^2+ elevation (2-10 sec), suggesting different mechanisms for these two components.

CONCLUSIONS.
These data add Ca^2+ mobilization to the signaling mechanisms activated by HDE, consistent with the involvement of protein kinase C-alpha in HDE responses. Multiple Ca^2+-mobilizing factors are present in HDE and mediate their Ca^2+ responses by different mechanisms. These Ca^2+-mobilizing factors likely contribute to the cytokine responses to HDE in isolated cells and to dust-induced lung disease in hog-barn workers. 
American Thoracic Society 2010 International Conference 
New Orleans, LA 
May 14-19, 2010