DEVELOPMENT OF NEW LIPID A BINDING AGENTS

描述：脓毒症影响数十万人的生活 在美国，每一种由革兰氏阴性细菌引起的败血症都是由 对内毒素的脂类A(LA)部分的不良宿主免疫反应。 对LA具有高亲和力的化合物，包括多粘菌素B(PMB)和 衍生品，能够解毒和保护宿主免受 败血症。通过与LA结合，这些化合物还能增敏革兰氏阴性 细菌对疏水抗生素的敏感性。然而，PMB的治疗用途 因其毒性而受到限制。这项研究的目的是开发 能够与LA强而选择性地缔合的小分子 用于治疗败血症和作为对抗细菌感染的手段。 本研究以PMB与LA的相互作用为模型，重点研究了PMB与LA的相互作用 以胆酸为基础的简单化合物的制备 脚手架，能够模拟PMB的LA结合行为，但 缺乏抗生素的毒性。简单胆酸基乳剂 与已报道的LA结合分子相比，粘合剂具有许多优点 包括：易于准备和衍生化，更好地控制 生物稳定性和潜在的口服生物利用度。胆酸 衍生品被设计成模仿PMB的构象，据信 重要的是它与洛杉矶的联系。初步实验： 胆酸衍生物显示了它们对革兰氏杆菌的敏化能力 疏水抗生素阴性菌与LA结合的行为 探员们。LA结合特性的优化将通过以下方式实现 胆酸连接氨基酸化合物文库的制备 酸性脚手架。将使用以下方法筛选文库以进行LA结合 亲和层析。亲和层析固定相 将由通过疏水相互作用固定化的LA组成 C18-二氧化硅颗粒或聚苯乙烯微珠。氨基酸的种类 有效的LA粘结剂将通过质谱学进行测定。新的 将测试La结合剂对Gram-2的敏化能力 阴性菌对疏水抗生素和/或抑制作用 LA对人单核细胞的作用(特别是产生白介素1b)。 PMB和新型LA-粘合剂与LA和LA衍生物的缔合 将用微量热法进行比较。

DESCRIPTION: Sepsis affects the lives of hundreds of thousands of people each in the U.S. Sepsis caused by Gram-negative bacteria results from adverse host immune response to the Lipid A (LA) portion of endotoxin. Compounds with high affinity for LA, including polymyxin B (PMB) and derivatives, are capable of detoxifying LA nd protection a host against sepsis. By binding LA, these compounds also sensitize Gram-negative bacteria to hydrophobic antibiotics. However, therapeutic use of PMB is limited due to its toxicity. The aim of this research is to develop small molecules capable of strong and selective associating with LA for use in treatment of sepsis and as means of fighting bacterial infection. Taking the interactions of PMB with LA as a model, this research focuses on the preparation of simple compounds, based on cholic acid scaffolding, capable of mimicking the LA-binding behavior of PMB but lacking the toxicity of the antibiotic. Simple cholic-acid based LA binders will present many advantages over reported LA binding molecules including: ease of preparation and derivatization, greater control over biological stability, and potential oral bioavailablity. Cholic acid derivatives were designed to mimic a conformation of PMB believed to be important in its association with LA. Preliminary experiments with cholic acid derivatives demonstrate their ability to sensitize Gram- negative bacteria to hydrophobic antibiotics, a behavior of LA binding agents. Optimization of LA-binding characteristics will be achieved by preparing libraries of compounds made up by amino acids linked to cholic acid scaffold. The libraries will be screened for LA binding using affinity chromatography. The affinity chromatography stationary phase will be made up of LA immobilized through hydrophobic interactions of C18- silica particles or polystyrene beads. The types of amino acids in effective LA binders will be determined via mass spectroscopy. New LA-binding agents will be tested for the ability to sensitize Gram- negative bacteria to hydrophobic antibiotics and/or inhibit the effects of LA on human monocytes (specifically interleukin 1b production). Association of PMB and the new LA-binders with LA and LA derivatives will be compared using microtitration calorimetry.