title: Molecular Weight-Dependent Immunostimulative Activity of Low Molecular Weight Chitosan via Regulating NF-κB and AP-1 Signaling Pathways in RAW264.7 Macrophages.
abstract: Chitosan and its derivatives such as low molecular weight chitosans (LMWCs) have been found to possess many important biological properties, such as antioxidant and antitumor effects. In our previous study, LMWCs were found to elicit a strong immunomodulatory response in macrophages dependent on molecular weight. Herein we further investigated the molecular weight-dependent immunostimulative activity of LMWCs and elucidated its mechanism of action on RAW264.7 macrophages. LMWCs (3 kDa and 50 kDa of molecular weight) could significantly enhance the mRNA expression levels of COX-2, IL-10 and MCP-1 in a molecular weight and concentration-dependent manner. The results suggested that LMWCs elicited a significant immunomodulatory response, which was dependent on the dose and the molecular weight. Regarding the possible molecular mechanism of action, LMWCs promoted the expression of the genes of key molecules in NF-κB and AP-1 pathways, including IKKβ, TRAF6 and JNK1, and induced the phosphorylation of protein IKBα in RAW264.7 macrophage. Moreover, LMWCs increased nuclear translocation of p65 and activation of activator protein-1 (AP-1, C-Jun and C-Fos) in a molecular weight-dependent manner. Taken together, our findings suggested that LMWCs exert immunostimulative activity via activation of NF-κB and AP-1 pathways in RAW264.7 macrophages in a molecular weight-dependent manner and that 3 kDa LMWC shows great potential as a novel agent for the treatment of immune suppression diseases and in future vaccines.
authors.affiliation: Zhejiang Provincial Key Engineering Technology Research Center of Marine Biomedical Products, School of Food Science and Pharmaceutics, Zhejiang Ocean University, Zhoushan 316022, China. 6369958@163.com.|Zhejiang Marine Development Research Institute, Zhoushan 316022, China. 6369958@163.com.
authors.forename: Bin
authors.initials: B
authors.lastname: Zheng
authors.affiliation: Zhejiang Provincial Key Engineering Technology Research Center of Marine Biomedical Products, School of Food Science and Pharmaceutics, Zhejiang Ocean University, Zhoushan 316022, China. zswenmr@163.com.
authors.forename: Zheng-Shun
authors.initials: ZS
authors.lastname: Wen
authors.affiliation: Zhoushan Hospital (Hospital of Chinese Medicine and Orthopedics), Zhoushan 316000, China. zsdrlz@126.com.
authors.forename: Yun-Juan
authors.initials: YJ
authors.lastname: Huang
authors.affiliation: Ocean College, Zhejiang University, Zhoushan 316021, China. msxia@zju.edu.cn.
authors.forename: Mei-Sheng
authors.initials: MS
authors.lastname: Xia
authors.affiliation: Zhejiang Marine Development Research Institute, Zhoushan 316022, China. xxw11086@126.com.
authors.forename: Xing-Wei
authors.initials: XW
authors.lastname: Xiang
authors.affiliation: Zhejiang Provincial Key Engineering Technology Research Center of Marine Biomedical Products, School of Food Science and Pharmaceutics, Zhejiang Ocean University, Zhoushan 316022, China. youle1960@163.com.
authors.forename: You-Le
authors.initials: YL
authors.lastname: Qu
keywords: NF-κB/AP-1; immunostimulative activity; low molecular weight chitosans; macrophages; molecular weight