Division of Pediatric Surgery Children's Hospital of Pittsburgh and Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America.
PLoS One. 2013 Jun 12;8(6):e65779. doi: 10.1371/journal.pone.0065779. Print 2013.
Many inflammatory diseases may be linked to pathologically elevated signaling via the receptor for lipopolysaccharide (LPS), toll-like receptor 4 (TLR4). There has thus been great interest in the discovery of TLR4 inhibitors as potential anti-inflammatory agents. Recently, the structure of TLR4 bound to the inhibitor E5564 was solved, raising the possibility that novel TLR4 inhibitors that target the E5564-binding domain could be designed. We utilized a similarity search algorithm in conjunction with a limited screening approach of small molecule libraries to identify compounds that bind to the E5564 site and inhibit TLR4. Our lead compound, C34, is a 2-acetamidopyranoside (MW 389) with the formula C17H27NO9, which inhibited TLR4 in enterocytes and macrophages in vitro, and reduced systemic inflammation in mouse models of endotoxemia and necrotizing enterocolitis. Molecular docking of C34 to the hydrophobic internal pocket of the TLR4 co-receptor MD-2 demonstrated a tight fit, embedding the pyran ring deep inside the pocket. Strikingly, C34 inhibited LPS signaling ex-vivo in human ileum that was resected from infants with necrotizing enterocolitis. These findings identify C34 and the β-anomeric cyclohexyl analog C35 as novel leads for small molecule TLR4 inhibitors that have potential therapeutic benefit for TLR4-mediated inflammatory diseases.
许多炎症性疾病可能与脂多糖（LPS）受体、Toll 样受体 4（TLR4）病理性升高的信号有关。因此，人们对发现 TLR4 抑制剂作为潜在的抗炎药产生了极大的兴趣。最近，TLR4 与抑制剂 E5564 结合的结构被解析，这增加了设计针对 E5564 结合域的新型 TLR4 抑制剂的可能性。我们利用相似性搜索算法结合小分子文库的有限筛选方法，鉴定出与 E5564 结合位点结合并抑制 TLR4 的化合物。我们的先导化合物 C34 是一种 2-乙酰氨基吡喃糖苷（MW 389），其化学式为 C17H27NO9，它在体外抑制肠细胞和巨噬细胞中的 TLR4，并减少内毒素血症和坏死性小肠结肠炎小鼠模型中的全身炎症。C34 与 TLR4 共受体 MD-2 的疏水内部口袋的分子对接表明，其紧密贴合，将吡喃环深深地嵌入口袋内。引人注目的是，C34 抑制了从患有坏死性小肠结肠炎的婴儿中切除的人回肠的 LPS 信号转导。这些发现确定了 C34 和β-氨基环己基类似物 C35 作为新型小分子 TLR4 抑制剂的先导化合物，它们可能对 TLR4 介导的炎症性疾病具有治疗益处。
