LSC 2011 Abstract: Differential inflammatory responses of nasal and bronchial epithelial cells to cigarette smoke extract

Few studies compare the function of primary bronchial (PBEC) and nasal (PNEC) epithelial cells. Our aim was to compare the responses of paired PNEC and PBEC cultures to LPS stimulation and any modulatory effects of exposure to cigarette smoke extract (CSE). Cells, from subjects with COPD, were obtained by nasal or bronchial brushing and used at passage 3. They were stimulated for 24 h with LPS [0–25 μg/ml] ± pre-treatment with CSE. CSE was prepared by combusting a 12 mg tar Marlboro cigarette through 25 ml of media. Supernatants were collected and IL-8 and IL-6 measured by ELISA. The localization of TLR-4 was established by FACS. For the PNEC cultures, a brief incubation with CSE (4h) significantly inhibited LPS-induced IL-6 and IL-8 release (IL-8: 24h treatment with 25 μg/ml LPS alone 5457±424 pg/ml and with 4h CSE pre-treatment 3772±432 pg/ml). A more prolonged incubation with CSE (24h) was pro-inflammatory (IL-8: 25 μg/ml LPS alone 5485±562 pg/ml and with 24h CSE pre-treatment 7757±449 pg/ml). Although a brief incubation with CSE resulted in a lower percentage of surface and intracellular TLR4, a prolonged incubation was without effect. In contrast, both a brief and a prolonged exposure of PBEC cultures to CSE reduced LPS induced IL-8 release (IL-8: 24h treatment with 25 μg/ml LPS alone 5107±797 pg/ml, with 4h CSE pre-treatment 3345±650 pg/ml, and with 24h CSE pre-treatment 3010±328 pg/ml), and both lead to a reduced percentage of surface and intracellular TLR4. There was minimal IL-6 release from the PBEC cultures. In conclusion, our data indicate that PNEC cultures are not a suitable surrogate for PBEC cultures in terms of their response to CSE/LPS combination treatment.