Effects of five chitosan oligosaccharides on nuclear factor-kappa B signaling pathway

The effects of five chito-oligomers, from dimer to hexamer (chitobiose, chitotriose, chitotetraose, chitopentaose, chitohexaose) separated from chitosan oligosaccharides, on nuclear factor -kappaB (NF-κB) signaling pathway were investigated by using luciferase assay and laser scanning microscopy. The expression of NF-κB downstream genes ( cyclin D1, TNFα and IL-6 ) were tested by real time PCR. We found that all five chitosan oligosaccharides increased NF-κB-dependent luciferase gene expression and NF-κB downstream genes transcription, and the most significant were chitotetraose and chitohexaose. In addition, laser scanning microscopy experiments showed that chitotetraose and chitohexaose also activated the p65 subunite of NF-κB translocating from cytoplasm to nucleus, which suggested that they were the most potent activators of NF-κB signaling pathway.