ABSTRACT
Objective:To investigate the regulatory effects of nuclear factor-κB (NF-κB) on dendritic cell (DC) maturation and function through solute carrier family 1 member 2 (Slc1a2).Methods:Mouse bone marrow-derived DCs were transfected with Slc1a2-specific siRNA and an overexpression Slc1a2 eukaryotic expression vector. The real-time fluorescence quantitation (RT-PCR) and Western Blot methods were used to detect knockdown and overexpression efficiency. The expression of surface molecules (CD40, CD80) and major histocompatibility complex Ⅱ (MHCⅡ) of DCs was detected by flow cytometry. ELISA was used to detect the secretion of the cytokines interleukin (IL)-12, IL-6, and transforming growth factor-β (TGF-β). The effects of knockdown of Slc1a2 on DC maturation and function and the effects of overexpression of Slc1a2 on DC maturation and function were reflected by the above assay results. A mixed lymphocyte culture assay was used to investigate the effect of Slc1a2 on T cell proliferation, and an ELISA was used to detect the lavel of IL-17A. Changes in the relative fluorescence intensity of FITC in DCs were analyzed by flow cytometry to investigate the ability of Slc1a2 overexpression on antigen phagocytosis. Finally, DCs were pretreated with an NF-κB inhibitor, toluoylphenylalanine chloromethyl ketone (TPCK), and the effect of TPCK on the expression of Slc1a2 in DCs and DC maturation was examined.Results:Slc1a2 expression was found to be high in DC treated with lipopolysaccharides (LPS) ( P<0.001). The knockdown of Slc1a2 decreased DC maturation and ability to stimulate the proliferation of CD4 + T cells ( P<0.001) and inhibited IL-17 secretion ( P<0.01). Overexpression of Slc1a2 promoted DC maturation and ability to stimulate the proliferation of CD4 + T cells(all P<0.01) Pretreatment of DC with the NF-κB inhibitor TPCK inhibited the expression of Slc1a2 at mRNA and protein levels induced by LPS. Conclusions:NF-κB regulates Slc1a2 expression, which affects the maturation and function of DC.
ABSTRACT
Fucoidan is a kind of sulfated polysaccharide with various biological activities that mainly exists in the cell walls of brown algae. It is also found in marine invertebrates such as sea cucumbers and sea urchins. Fucoidan has received a lot of attention due to its tumor-killing and immune-boosting properties. Moreover, the combination of fucoidan with chemotherapeutic drugs not only improves antitumor efficacy but also reduces the side effects of these drugs. The function of fucoidan is closely correlated with its structure, molecular weight, degree of sulfation, monosaccharide component, algae source, and time of collection. In this review, the antitumor and immunomodulatory effects of fucoidan are reviewed from the aspects of promoting cell apoptosis, inducing cell cycle arrest, inhibiting angiogenesis and cell migration, and activating immune cells, to provide theoretical guidance for the development and clinical application of fucoidan.