Dependence of pathogen molecule-induced Toll-like receptor activation and cell function on Neu1 sialidase
Dependence of pathogen molecule-induced Toll-like receptor activation and cell function on Neu1 sialidase
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DOI：
10.1007/s10719-009-9239-8
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发表时间：
2009-12-01
影响因子：
3
通讯作者：
Szewczuk, Myron R.
中科院分区：
文献类型：
--
作者：
Amith, Schammim Ray;Jayanth, Preethi;Szewczuk, Myron R.
哺乳动物Toll样受体（TLR）的信号传导途径被很好地表征，但配体与受体相互作用后激活的初始分子机制仍然不清楚。在这里，我们展示了一种膜控制机制，该机制是通过与TLR-2，-3和-4结合的配体启动的，以在几分钟内在活的原代骨髓（BM）巨噬细胞和巨噬细胞和树突状细胞系中诱导Neu 1唾液酸酶活性。该过程的中心是Neu 1而不是Neu 2、-3和-4与幼稚巨噬细胞的细胞表面上的TLR-2、-3和-4形成复合物。神经氨酸酶抑制剂BCX 1827、2-脱氧-2，3-脱氢-N-乙酰神经氨酸（DANA）、扎那米韦和奥司他韦羧酸盐对活BMC-2巨噬细胞中LPS诱导的唾液酸酶活性具有有限的显著抑制作用，但达菲（磷酸奥司他韦）完全阻断该活性。达菲在活BMC-2细胞中抑制LPS诱导的唾液酸酶活性，IC 50为1.2 μ M，而其水解代谢物奥司他韦羧酸盐的IC 50为1015 μ M。达菲阻断LPS诱导的Neu 1唾液酸酶活性在用抗羧酸酯酶剂氯吡格雷预处理的BMC-2细胞中不受影响。内毒素LPS与TLR 4结合诱导Neu 1，随后在原代和巨噬细胞系中激活NF κ B并产生一氧化氮和促炎性IL-6和TNF α细胞因子。继发性Neu 1缺陷的低形态组织蛋白酶A小鼠与正常Neu 1小鼠的野生型或低形态组织蛋白酶A相比，对LPS诱导的促炎细胞因子的反应较差。我们的研究结果建立了病原体分子诱导的TLR激活和细胞功能的前所未有的机制，这是严重依赖于与TLR配体处理的活的原代巨噬细胞和巨噬细胞和树突状细胞系相关的Neu 1唾液酸酶活性。
The signaling pathways of mammalian Toll-like receptors (TLR) are well characterized, but the initial molecular mechanisms activated following ligand interactions with the receptors remain poorly defined. Here, we show a membrane controlling mechanism that is initiated by ligand binding to TLR-2, -3 and-4 to induce Neu1 sialidase activity within minutes in live primary bone marrow (BM) macrophage cells and macrophage and dendritic cell lines. Central to this process is that Neu1 and not Neu2,-3 and-4 forms a complex with TLR-2,-3 and-4 on the cell surface of na < ve macrophage cells. Neuraminidase inhibitors BCX1827, 2-deoxy-2,3-dehydro-N-acetylneuraminic acid (DANA), zanamivir and oseltamivir carboxylate have a limited significant inhibition of the LPS-induced sialidase activity in live BMC-2 macrophage cells but Tamiflu (oseltamivir phosphate) completely blocks this activity. Tamiflu inhibits LPS-induced sialidase activity in live BMC-2 cells with an IC50 of 1.2 mu M compared to an IC50 of 1015 mu M for its hydrolytic metabolite oseltamivir carboxylate. Tamiflu blockage of LPS-induced Neu1 sialidase activity is not affected in BMC-2 cells pretreated with anticarboxylesterase agent clopidogrel. Endotoxin LPS binding to TLR4 induces Neu1 with subsequent activation of NF kappa B and the production of nitric oxide and pro-inflammatory IL-6 and TNF alpha cytokines in primary and macrophage cell lines. Hypomorphic cathepsin A mice with a secondary Neu1 deficiency respond poorly to LPS-induced pro-inflammatory cytokines compared to the wild-type or hypomorphic cathepsin A with normal Neu1 mice. Our findings establish an unprecedented mechanism for pathogen molecule-induced TLR activation and cell function, which is critically dependent on Neu1 sialidase activity associated with TLR ligand treated live primary macrophage cells and macrophage and dendritic cell lines.