Immunoregulatory activity of an alkaline-precipitated polysaccharide CGP-AP produced by Chaetomium globosum CGMCC 6882
Shuaiyang Wang, Na Li, Ye Zhang, Xueyan Zhou, Renyong Zhao, Minjie Gao, Zhitao Li, Lemei An, Zichao Wang, Shaobo Duan
Abstract
This work characterized the structural features and investigated the immunomodulatory activity of an alkaline-precipitated polysaccharide fraction produced by Chaetomium globosum CGMCC 6882 (CGP-AP) in RAW 264.7 macrophages. The CGP-AP yield was 0.93 ± 0.08 g/L, which contained 98.33% ± 2.04% (w/w) carbohydrate and 1.52% ± 0.26% (w/w) protein. Structural analysis showed that CGP-AP comprised glucose (99.51%) and arabinose (0.49%), its weight (Mw) and number (Mn) average molecular weights were 0.948 and 0.55 kDa, and its polydispersity (Mw/Mn) was 1.724. In vitro immunomodulatory results show that CGP-AP stimulated nitric oxide production and tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-8 secretion via upregulation of the expression levels of related genes in RAW 264.7 macrophages. Meanwhile, CGP-AP upregulated the expression levels of proinflammatory genes (inducible nitric oxide synthase and cyclooxygenase-2 COX-2). Furthermore, CGP-AP improved the antioxidant status of RAW 264.7 cells by increasing antioxidase (superoxide dismutase, catalase, and glutathione peroxidase) levels and enhancing the mRNA expression of nuclear factor erythroid-2 related factor 2. The above results indicate that CGP-AP may be used as a potential immunomodulator in the pharmaceutical industry.