Laboratory of Biomedical Science and Department of Medicinal Chemistry, The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA.
Proc Natl Acad Sci U S A. 2010 Jun 29;107(26):11942-7. doi: 10.1073/pnas.1003893107. Epub 2010 Jun 14.
During infection, vertebrates develop "sickness syndrome," characterized by fever, anorexia, behavioral withdrawal, acute-phase protein responses, and inflammation. These pathophysiological responses are mediated by cytokines, including TNF and IL-1, released during the innate immune response to invasion. Even in the absence of infection, qualitatively similar physiological syndromes occur following sterile injury, ischemia reperfusion, crush injury, and autoimmune-mediated tissue damage. Recent advances implicate high-mobility group box 1 (HMGB1), a nuclear protein with inflammatory cytokine activities, in stimulating cytokine release. HMGB1 is passively released during cell injury and necrosis, or actively secreted during immune cell activation, positioning it at the intersection of sterile and infection-associated inflammation. To date, eight candidate receptors have been implicated in mediating the biological responses to HMGB1, but the mechanism of HMGB1-dependent cytokine release is unknown. Here we show that Toll-like receptor 4 (TLR4), a pivotal receptor for activation of innate immunity and cytokine release, is required for HMGB1-dependent activation of macrophage TNF release. Surface plasmon resonance studies indicate that HMGB1 binds specifically to TLR4, and that this binding requires a cysteine in position 106. A wholly synthetic 20-mer peptide containing cysteine 106 from within the cytokine-stimulating B box mediates TLR4-dependent activation of macrophage TNF release. Inhibition of TLR4 binding with neutralizing anti-HMGB1 mAb or by mutating cysteine 106 prevents HMGB1 activation of cytokine release. These results have implications for rationale, design, and development of experimental therapeutics for use in sterile and infectious inflammation.
在感染过程中，脊椎动物会发展出“疾病综合征”，其特征为发热、厌食、行为退缩、急性期蛋白反应和炎症。这些病理生理反应是由细胞因子介导的，包括 TNF 和 IL-1，它们在先天免疫反应入侵时释放。即使没有感染，在无菌损伤、缺血再灌注、挤压伤和自身免疫介导的组织损伤后，也会发生类似的生理综合征。最近的进展表明，高迁移率族蛋白 B1（HMGB1），一种具有炎症细胞因子活性的核蛋白，在刺激细胞因子释放中起作用。HMGB1 在细胞损伤和坏死时被动释放，或在免疫细胞激活时主动分泌，使其处于无菌和感染相关炎症的交叉点。迄今为止，已有 8 种候选受体被认为参与介导对 HMGB1 的生物学反应，但 HMGB1 依赖性细胞因子释放的机制尚不清楚。在这里，我们表明 Toll 样受体 4（TLR4）是先天免疫和细胞因子释放激活的关键受体，是 HMGB1 依赖性巨噬细胞 TNF 释放所必需的。表面等离子体共振研究表明，HMGB1 特异性结合 TLR4，并且这种结合需要第 106 位的半胱氨酸。包含 B 盒内第 106 位半胱氨酸的完全合成 20 肽肽介导 TLR4 依赖性巨噬细胞 TNF 释放的激活。用中和 HMGB1 mAb 抑制 TLR4 结合或突变半胱氨酸 106 可防止 HMGB1 激活细胞因子释放。这些结果对无菌和感染性炎症的实验治疗的合理设计、设计和开发具有重要意义。
