Involvement of Toll-like receptor (TLR) 2 and TLR4 in cell activation by mannuronic acid polymers
Involvement of Toll-like receptor (TLR) 2 and TLR4 in cell activation by mannuronic acid polymers
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DOI：
10.1074/jbc.m201366200
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发表时间：
2002-09-20
影响因子：
4.8
通讯作者：
Espevik, T
中科院分区：
文献类型：
--
作者：
Flo, TH;Ryan, L;Espevik, T
由人类病原体铜绿假单胞菌产生的藻酸盐胶囊主要由具有免疫刺激特性的甘露糖醛酸聚合物（poly-M）组成。Poly-M与脂多糖具有以CD 14依赖性方式刺激人单核细胞产生细胞因子的能力。在本研究中，我们研究了Toll样受体（TLR）2和TLR 4在多聚-M反应中的作用。TLR 2和TLR 4的阻断抗体部分抑制了人单核细胞中多聚-M诱导的肿瘤坏死因子的产生，并且通过结合抗体获得了进一步的抑制。通过瞬时转染HEK 293细胞，我们发现膜CD 14与TLR 2或TLR 4/MD-2一起可以介导poly-M的激活。用TLR 2和荧光标记的TLR 4转染HEK 293细胞，然后用抗体共修补TLR 2，显示这些分子在质膜上没有结合。然而，来自Tlr 4突变型C3 H1 HeJ小鼠和TLR 4敲除小鼠的巨噬细胞对聚-M完全无应答，而来自TLR 2敲除巨噬细胞的肿瘤坏死因子释放是野生型细胞所见的一半。总之，结果表明，TLR 2和TLR 4都参与了多聚-M的细胞活化，并且原代鼠巨噬细胞中可能需要TLR 4。
The alginate capsule produced by the human pathogen Pseudomonas aeruginosa is composed mainly of mannuronic acid polymers (poly-M) that have immunostimulating properties. Poly-M shares with lipopolysaccharide the ability to stimulate cytokine production from human monocytes in a CD14-dependent manner. In the present study we examined the role of Toll-like receptor (TLR) 2 and TLR4 in responses to poly-M. Blocking antibodies to TLR2 and TLR4 partly inhibited tumor necrosis factor production induced by poly-M in human monocytes, and further inhibition was obtained by combining the antibodies. By transiently transfecting HEK293 cells, we found that membrane CD14 together with either TLR2 or TLR4/MD-2 could mediate activation by poly-M. Transfection of HEK293 cells with TLR2 and fluorescently labeled TLR4 followed by co-patching of TLR2 with an antibody revealed no association of these molecules on the plasma membrane. However, macrophages from the Tlr4 mutant C3H1HeJ mice and TLR4 knockout mice were completely non-responsive to poly-M, whereas the tumor necrosis factor release from TLR2 knockout macrophages was half of that seen with wild type cells. Taken together the results suggest that both TLR2 and TLR4 are involved in cell activation by poly-M and that TLR4 may be required in primary murine macrophages.