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-kappa B) signaling pathway were investigated by using luciferase assay and laser scanning microscopy. The expression of NF-kappa B downstream genes (cyclin D1, TNF alpha and IL-6) were tested by real time PCR. We found that all five chitosan oligosaccharides increased NF-kappa B-dependent luciferase gene expression and NF-kappa B 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-kappa B translocating from cytoplasm to nucleus, which suggested that they were the most potent activators of NF-kappa B signaling pathway.