Amphiphilic pyridinium salts block TNFα/NFκB signaling and constitutive hypersecretion of interleukin-8 (IL-8) from cystic fibrosis lung epithelial cells
作者:Susanna Tchilibon、Jian Zhang、QingFeng Yang、Ofer Eidelman、Haksung Kim、Hung Caohuy、Kenneth A. Jacobson、Bette S. Pollard、Harvey B. Pollard
DOI:10.1016/j.bcp.2005.05.002
日期:2005.8
Cystic fibrosis (CF) is a common, lethal genetic disease, which is due to mutations in the CFTR gene. The CF lung expresses a profoundly proinflammatory phenotype, due to constitutive hypersecretion of IL-8 from epithelial cells lining the airways. In a systematic search for candidate drugs that might be used therapeutically to suppress IL-8 secretion from these cells, we have identified a potent and efficacious series of amphiphilic pyridinium salts. The most potent of these salts is MRS2481, an (R)-1-phenylpropionic acid ester, with an IC50 of ca. 1 mu M. We have synthesized 21 analogues of MRS2481, which have proven sufficient to develop a preliminary structure-activity relationship (SAR). For optimal activity, we have found that the ester must be connected to the pyridinium derivative by an eight-carbon chain. An optical isomer of the lead compound, containing an (S)-1-phenylpropionic acid ester, has been found to be a much less active. The mechanism of action of MRS2481 appears to involve inhibition of signaling of the NF kappa B and AP- I transcription factors to the IL-8 promoter. MRS2481 is a potent inhibitor of TNF alpha-induced phosphorylation and proteosomal destruction Of I kappa B alpha. Inasmuch as I kappa B alpha is the principal inhibitor of the NF kappa B signaling pathway, preservation of intact I kappa B alpha would serve to keep the IL-8 promoter silent. We also find that MRS2481 blocks TNF alpha-activated phosphorylation of JNK, the c-JUN kinase. The IL-8 promoter is also activated by an AP- I site, which requires a phospho-c-JUN/c-FOS dimer for activity. We therefore interpret these data to suggest that the mechanism of MRS2481 action is to inhibit both NF kappa B and AP-1 signaling on the IL-8 promoter. Given the medicinally promising properties of water-solubility, potency in the low mu M concentration range, and high efficacy, we anticipate that MRS2481, or a further optimized derivative, may find an important place in the armamentarium of pharmaceutical strategies yet to be arrayed against the inflammatory phenotype of the CF lung. Published by Elsevier Inc.