IN SCHOOL ARTICLE Vitamin D3 Blocks NFkB Activation in an In Vitro Model of Cystic Fibrosis

In this study, the inflammatory responses in isogenic lung epithelial cell lines derived from a patient with Cystic Fibrosis (CFBE41o- ∆F508 and CFBE41o- N) were examined. The first cell line overexpresses the ∆F508 deletion mutation leading to Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein dysfunction, while the second line overexpresses a normal allele of CFTR. Cells expressing the mutated CFTR protein have been shown to be more sensitive to inflammatory pathways mediated by the toll-like receptor 2 (TLR2) 1. We hypothesized that CF cell lines would show an elevated inflammatory response when stimulated through this pathway and that this inflammatory response could be reduced by treatment with Vitamin D3. Vitamin D3 has been described to modulate TLR expression and is a known suppressor of the TLR2 and TLR4 pathways 2. An inflammatory response was induced in the cells using MALP-2, a TLR2/6-specific ligand. Translocation of NFkB to the nucleus, as evidenced by immunofluorescent localization of nuclear NFkB, was used as an indicator of pro-inflammatory signaling. It was found that 16 % of the cells expressing normal CFTR treated with MALP-2 showed NFkB nuclear translocation versus 28 % of the ∆F508 cells treated with MALP-2. This almost two-fold increase in NFkB translocation strongly suggests that the ∆F508 cells may indeed be more sensitive to inflammation than the cells expressing normal CFTR. The potential role for Vitamin D3 in mitigating this inflammatory response was then examined. When the cells expressing normal CFTR were treated with MALP-2 and Vitamin D3, 5 % of the cells expressed activated NFkB. When the same experiment was performed with cells expressing the mutation, 9 % of the cells treated with MALP-2 and Vitamin D3 had translocated NFkB These results provide evidence for both the potential claim that ∆F508 cells are more sensitive to inflammation via TLR pathways and that Vitamin D3 does in fact reduce the inflammatory response in Cystic Fibrosis cells