title: Protective effect of polysaccharides on simulated microgravity-induced functional inhibition of human NK cells.
abstract: Polysaccharides are believed to be strong immunostimulants that can promote the proliferation and activity of T cells, B cells, macrophages and natural killer (NK) cells. This study aimed to investigate the effects of five polysaccharides (Grifola frondosa polysaccharide (GFP), lentinan (LNT), G. lucidum polysaccharide (GLP), Lycium barbarum polysaccharide (LBP) and yeast glucan (YG)) on primary human NK cells under normal or simulated microgravity (SMG) conditions. Our results demonstrated that polysaccharides markedly promoted the cytotoxicity of NK cells by enhancing IFN-γ and perforin secretion and increasing the expression of the activating receptor NKp30 under normal conditions. Meanwhile polysaccharides can enhance NK cell function under SMG conditions by restoring the expression of the activating receptor NKG2D and reducing the early apoptosis and late apoptosis/necrosis. Moreover, the antibody neutralization test showed that CR3 may be the critical receptor involved in polysaccharides induced NK cells activation. These findings indicated that polysaccharides may be used as immune regulators to promote the health of the public and astronauts during space missions.
authors.affiliation: Key Laboratory for Space Bioscience and Space Biotechnology, School of Life Sciences, Northwestern Polytechnical University, 127 Youyi Xilu, Xi'an 710072, Shaanxi, PR China; School of Materials Science and Engineering, Northwestern Polytechnical University, 127 Youyi Xilu, Xi'an 710072, Shaanxi, PR China.
authors.forename: Ting
authors.initials: T
authors.lastname: Huyan
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Jin
authors.forename: Ming-Jie
authors.initials: MJ
authors.lastname: Zhang
authors.forename: Lin-Jie
authors.initials: LJ
authors.lastname: Ye
authors.forename: Ji
authors.initials: J
authors.lastname: Li
authors.forename: Qing-Sheng
authors.initials: QS
authors.lastname: Huang
authors.forename: Da-Chuan
authors.initials: DC
authors.lastname: Yin
mesh_terms: D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000166:cytology* / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects; D011134:Polysaccharides / Q000494:pharmacology*; D011951:Receptors, Complement / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D018474:Weightlessness Simulation / Q000009:adverse effects*
chemical_list: D011134:Polysaccharides; D011951:Receptors, Complement
keywords: Cytotoxicity; Human natural killer (NK) cell; Polysaccharide; Simulated microgravity (SMG)