Yamawaki Hitoshi, Hirohata Satoshi, Miyoshi Toru, Takahashi Katsuyuki, Ogawa Hiroko, Shinohata Ryoko, Demircan Kadir, Kusachi Shozo, Yamamoto Kazuhide, Ninomiya Yoshifumi
Department of Molecular Biology and Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan.
Glycobiology. 2009 Jan;19(1):83-92. doi: 10.1093/glycob/cwn109. Epub 2008 Oct 14.
During inflammation, lower molecular weight fragments of hyaluronan accumulate, and this is known to be inflammatory and immune-stimulatory. In diseases such as inflammatory bowel disease, inflammatory cells bind to hyaluronan; however, the cellular response and molecular mechanism of hyaluronan-hyaluronan receptor interactions in mononuclear cells are not well understood. The expression of hyaluronan receptors in peripheral blood mononuclear cells (PBMC) was examined. PBMC were stimulated with lower and higher molecular weight hyaluronan (molecular weight 100-150 kDa and 2700 kDa) and the induction of proinflammatory cytokines (interleukin-6 (IL-6) and monocyte chemoattractant protein (MCP-1)) was compared by enzyme-linked immunoabsorbant assay (ELISA). Cells were coincubated with various signaling pathway inhibitors. In addition, neutralizing antibodies against CD44 and TLR4 were added and the effects on PBMC were investigated. Finally, mononuclear cells from CD44-null and toll-like receptor 4 (TLR4) mutant mice were both stimulated with lower molecular weight hyaluronan. Among the hyaluronan receptors, TLR4 and CD44 were markedly expressed on PBMC. Hyaluronan-stimulated PBMC enhanced the attachment to the extracellular matrix. Lower molecular weight hyaluronan induced IL-6 and MCP-1 production in PBMC, but high-molecular-weight hyaluronan did not induce IL-6 and MCP-1 production. An anti-CD44 antibody attenuated the induction of both IL-6 and MCP-1 in lower molecular weight hyaluronan-stimulated PBMC. In both TLR4 mutant and CD44-null mice, the induction of IL-6 by lower molecular weight hyaluronan stimulation was decreased. SB203580 completely abolished IL-6 production in both TLR4 mutant and CD44-null mononuclear cells, while PD98059 abolished IL-6 production in CD44-null mononuclear cells. Hyaluronan receptors, CD44 and TLR4, play distinct roles in cytokine induction in hyaluronan-stimulated mononuclear cells.
在炎症过程中，透明质酸的低分子量片段会积累，已知其具有炎症性和免疫刺激作用。在炎症性肠病等疾病中，炎症细胞会与透明质酸结合；然而，单核细胞中透明质酸-透明质酸受体相互作用的细胞反应和分子机制尚不清楚。研究了外周血单核细胞（PBMC）中透明质酸受体的表达。用低分子量和高分子量透明质酸（分子量分别为100 - 150 kDa和2700 kDa）刺激PBMC，并通过酶联免疫吸附测定（ELISA）比较促炎细胞因子（白细胞介素-6（IL-6）和单核细胞趋化蛋白（MCP-1））的诱导情况。将细胞与各种信号通路抑制剂共同孵育。此外，加入抗CD44和TLR4的中和抗体，并研究其对PBMC的影响。最后，用低分子量透明质酸刺激来自CD44基因敲除小鼠和Toll样受体4（TLR4）突变小鼠的单核细胞。在透明质酸受体中，TLR4和CD44在PBMC上显著表达。透明质酸刺激的PBMC增强了与细胞外基质的附着。低分子量透明质酸诱导PBMC产生IL-6和MCP-1，但高分子量透明质酸不诱导IL-6和MCP-1的产生。抗CD44抗体减弱了低分子量透明质酸刺激的PBMC中IL-6和MCP-1的诱导。在TLR4突变小鼠和CD44基因敲除小鼠中，低分子量透明质酸刺激诱导的IL-6均减少。SB203580完全消除了TLR4突变和CD44基因敲除单核细胞中IL-6的产生，而PD98059消除了CD44基因敲除单核细胞中IL-6的产生。透明质酸受体CD44和TLR4在透明质酸刺激的单核细胞的细胞因子诱导中发挥不同作用。
