Airway epithelial acute phase responses

Abstract

RATIONALE: Acute phase proteins are commonly upregulated in liver in response to microbial infections and inflammation. We determined whether a local acute phase response may be exhibited by airway epithelial cells when challenged by pathogens. The influence of airway epithelial cell challenge with the TLR-3 ligand dsRNA (25μg/ml) and pro-inflammatory cytokines TNF-α (100ng/ml) and IL-6 (50ng/ml) on expression of mRNA for acute phase proteins was determined. METHODS: BEAS-2B epithelial cells were stimulated for 18 hrs, and RNA isolated and analyzed for C-Reactive protein (CRP), Pentraxin-3 (PTX3), Complement Factor B (B), Lysozyme (LYS), Complement C3 (C3), Factor P (P), Factor H (H), LPS-binding protein (LBP), Intelectin 2 (ITL) and SLPI by Taqman Real-Time PCR. RESULTS: The order of basal mRNA expression observed in BEAS-2B from highest to lowest was: B > PTX3 > LYS∼C3∼P∼H > CRP∼LBP∼ ITL∼SLPI (n=5-8). Stimulation with dsRNA significantly enhanced expression of PTX3 (23 ± 1.5 fold, ∗=p<0.05, n=5), B (25 ± 0.8∗), H (15 ± 1∗), SLPI (5.7 ± 0.7∗) and C3 (22 ± 1.7∗). Mild induction of less than 3 fold was also observed for CRP, LYS, LBP and ITL (p>0.05, n=5). Stimulation with TNF-α increased mRNA for PTX3 (21 ± 1 fold∗, n=3) and C3 (27 ± 2 fold, p<0.06, n=3). CONCLUSIONS: These studies demonstrate basal and inducible expression of acute phase genes in BEAS-2B Cells. These data suggest that airway epithelial cells may exhibit a local acute phase response when directly exposed to pathogens.