Intracellular distribution of NFκB decoy and its inhibitory effect on TNFα production by LPS stimulated RAW 264.7 cells

Nuclear factor kappa B (NFκB) is a transcriptional factor for the expression of many cytokines that are involved in the pathogenesis of inflammatory diseases. Unstimulated NFκB sequestered in the cytoplasm bound to inhibitory proteins is called IκBs. Many activators of NFκB cause degradation of IκB proteins and free NFκB can enter the nucleus and induce gene expression. In this study, we analyzed the relationship between the intracellular distribution and pharmacological effect of NFκB decoy in RAW 264.7 cells. Most of the fluorescent labeled NFκB decoy was observed in the cytoplasm both with or without cationic transfection without LPS stimulation. Furthermore, under LPS stimulation, most of NFκB decoy was also observed in the cytoplasm. However, NFκB decoy effectively inhibited the production of TNFα in RAW 264.7 cells. The inhibitory effect of TNFα production by NFκB decoy transfected by cationic liposomes was much stronger than that by naked NFκB decoy, because the amount of cellular association of NFκB transfected by cationic liposome decoy was 7 times higher than that of naked NFκB decoy. This information is of great value for the design of NFκB decoy carrier systems.