School of Life Science and Technology, China Pharmaceutical University, Nanjing, 211198, China.
Fundam Clin Pharmacol. 2020 Oct;34(5):591-602. doi: 10.1111/fcp.12550. Epub 2020 Mar 10.
Exopolysaccharide from Aphanothece halophytica (EPSAH), a potent antitumor agent and immunological adjuvant, was investigated for the activation effect on RAW264.7 macrophages and the underlying mechanisms. EPSAH could significantly enhance macrophage phagocytosis and the secretion of nitric oxide, increase the mRNA expression levels of the pro-inflammatory cytokines (IL-1β, IL-6, IL-12, and TNF-α), anti-inflammatory cytokine IL-10, and chemokines (MCP-1 and MIP-1α). When RAW264.7 cells were treated with EPSAH, the mRNA expression of TLR4 and its downstream molecules TRAF6 and MyD88 were upregulated. When TLR4 was blocked using a TLR4-specific neutralizing antibody, nitric oxide secretion from the macrophages was significantly inhibited. EPSAH was further shown to induce phosphorylation of the mitogen-activated protein kinases (MAPKs) ERK, JNK, and p38, and promote cytoplasmic IκB phosphorylation and increase nuclear NF-κB p65 levels remarkably in RAW264.7 cells. These data demonstrate the capacity of EPSAH to induce macrophage activation possibly via TLR4/MyD88 pathway, which leads to the activation of its main signaling downstream molecules MAPKs and NF-κB.
从盐生杜氏藻（EPSAH）中提取的胞外多糖（EPSAH）是一种有效的抗肿瘤药物和免疫佐剂，研究其对 RAW264.7 巨噬细胞的激活作用及其机制。EPSAH 能显著增强巨噬细胞的吞噬作用和一氧化氮的分泌，增加促炎细胞因子（IL-1β、IL-6、IL-12 和 TNF-α）、抗炎细胞因子 IL-10 和趋化因子（MCP-1 和 MIP-1α）的 mRNA 表达水平。当 RAW264.7 细胞用 EPSAH 处理时，TLR4 及其下游分子 TRAF6 和 MyD88 的 mRNA 表达上调。当使用 TLR4 特异性中和抗体阻断 TLR4 时，巨噬细胞中一氧化氮的分泌显著抑制。此外，EPSAH 还能显著诱导 MAPKs（ERK、JNK 和 p38）的磷酸化，促进细胞质 IκB 磷酸化，并显著增加 RAW264.7 细胞中核 NF-κB p65 水平。这些数据表明，EPSAH 可能通过 TLR4/MyD88 途径诱导巨噬细胞活化，从而激活其主要信号转导下游分子 MAPKs 和 NF-κB。
