Piao Wenji, Shirey Kari Ann, Ru Lisa W, Lai Wendy, Szmacinski Henryk, Snyder Greg A, Sundberg Eric J, Lakowicz Joseph R, Vogel Stefanie N, Toshchakov Vladimir Y
Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Department of Biochemistry and Molecular Biology and Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Cell Rep. 2015 Jun 30;11(12):1941-52. doi: 10.1016/j.celrep.2015.05.035. Epub 2015 Jun 18.
Toll-like receptors (TLRs) activate distinct, yet overlapping sets of signaling molecules, leading to inflammatory responses to pathogens. Toll/interleukin-1 receptor (TIR) domains, present in all TLRs and TLR adapters, mediate protein interactions downstream of activated TLRs. A peptide library derived from TLR2 TIR was screened for inhibition of TLR2 signaling. Cell-permeable peptides derived from the D helix and the segment immediately N-terminal to the TLR2 TIR domain potently inhibited TLR2-mediated cytokine production. The D-helix peptide, 2R9, also potently inhibited TLR4, TLR7, and TLR9, but not TLR3 or TNF-α signaling. Cell imaging, co-immunoprecipitation, and in vitro studies demonstrated that 2R9 preferentially targets TIRAP. 2R9 diminished systemic cytokine responses elicited in vivo by synthetic TLR2 and TLR7 agonists; it inhibited the activation of macrophages infected with influenza strain A/PR/8/34 (PR8) and significantly improved the survival of PR8-infected mice. Thus, 2R9 represents a TLR-targeting agent that blocks protein interactions downstream of activated TLRs.
Toll样受体（TLRs）激活不同但部分重叠的信号分子组，引发对病原体的炎症反应。存在于所有TLRs和TLR衔接蛋白中的Toll/白细胞介素-1受体（TIR）结构域介导活化TLRs下游的蛋白质相互作用。对源自TLR2 TIR的肽库进行筛选以寻找TLR2信号传导的抑制剂。源自D螺旋和紧邻TLR2 TIR结构域N端的片段的细胞可渗透肽有效抑制TLR2介导的细胞因子产生。D螺旋肽2R9也有效抑制TLR4、TLR7和TLR9，但不抑制TLR3或TNF-α信号传导。细胞成像、免疫共沉淀和体外研究表明2R9优先靶向TIRAP。2R9减少了合成TLR2和TLR7激动剂在体内引发的全身细胞因子反应；它抑制感染甲型流感病毒A/PR/8/34（PR8）的巨噬细胞的活化，并显著提高PR8感染小鼠的存活率。因此，2R9代表一种靶向TLR的药物，可阻断活化TLRs下游的蛋白质相互作用。
