Citation:

MANZO, N., J. A. DYE, J. E. RICHARDS, R. SLADE, AND L. D. MARTIN. THE EFFECTS OF COMBINATORIAL EXPOSURE OF PRO-INFLAMMATORY AND ANTI-INFLAMMATORY CYTOKINES ON AIRWAY EPITHELIAL CELL RELEASE OF CHEMOTACTIC MEDIATORS. Presented at North Carolina State University Veterinary School Research Forum, Raleigh, NC, March 17, 2006.

Description:

Asthma is a chronic inflammatory disorder of the airways affecting nearly 15 million individuals nationally. Within the inflamed asthmatic airway there exist complex interactions between many cells and the cytokines they release, in particular mast cells, eosinophils, T-lymphocytes, neutrophils and epithelial cells. While several cytokines are involved in initiating and sustaining inflammation, increased IL-1b and TNFa (likely from alveolar macropohages) as well as INFc (from T/H1 lymphocytes) have been found in the lungs of asthmatics. IL-1b and TNFa are classified as pro-inflammatory cytokines, while INFc has been shown to elicit both anti- and pro-inflammatory effects. Exposure of airway epithelial cells to such mediators in turn activates the production of chemokines, such as of the neutrophil attractant, MIP-2, and the eosinophilic modulator, RANTES, which are responsible for the recruitment of inflammatory cells to the airway.We set out to model the 'pre-existing airway inflammation' present in asthmatics using a mouse cell culture system that simulates some of the pathophysiologic conditions within the airways. When cultured in the appropriate conditions and maintained in an air-liquid interface, this system provides a cell population of polarized, pseudo-differentiated airway cells (consisting of ciliated, non-ciliated and mucus producing cells). It is our hypothesis that epithelial exposure to IL-1b and TNFa either individually, or in combination, will stimulate increases in MIP-2 and RANTES release; the effects of which will be decreased during co-exposure with INFc. Primary mouse tracheal (MTE) cell cultures were harvested from the tracheas of female C57Bl/6 mice and seeded into the transwells of a 12well cluster plate, and exposed to the cytokines either apically or basally for 24 hrs. The apical and basal supernatants were collected at 24, 48, and 72 hrs for endpoint assessment. Release of MIP-2 and RANTES was measured by ELISAs. The degree of injury due to treatment was inferred by the integrity of the plasma membrane through the release of lactate dehyrodgenase (LDH) from damaged cells. Dose-response increases were observed in MIP-2 and RANTES release in cells exposed to either IL-1b or TNFa, and in combination, with IL1b predominating these effects at 24 hrs; effects largely waned by 48hrs. Interestingly, co-exposure of IL-1b and TNFa with IFNc potentiated these effects and prolonged the duration of the response up to 72 hrs. In conclusion, under conditions of simultaneous exposure to IFNc in the presence of the pro-inflammatory mediators IL-1b and TNFa, IFNc acts as an pro-inflammatory cytokine, stimulating the neutrophil and eosinophil attractants MIP-2 and RANTES, respectively, from mouse airway epithelial cells. Further studies will utilize this model airway system to better assess the interplay between pre-existing airway inflammation and exposure to air pollutants, such as diesel exhaust particles, in an effort to develop predictive exposure responses to better evaluate the potential health risk on susceptible populations. (Abstract does not represent US EPA policy) Funded by the NCSU/EPA Cooperative Training Program in Environmental Sciences Research, Training Agreement CT826512010

Record Details:

Record Type:DOCUMENT( PRESENTATION/ ABSTRACT)

Product Published Date:03/17/2006

Record Last Revised:06/21/2006

Record ID: 149129

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