Arf6 Inhibition as Novel Treatment for Multidrug Resistance Gram Negative Infections

Arf6 抑制作为多重耐药革兰氏阴性菌感染的新疗法

• 批准号: 9755205
• 负责人: ASHRAF S. IBRAHIM
• 金额: $ 48.15万
• 依托单位: LUNDQUIST INSTITUTE FOR BIOMEDICAL INNOVATION AT HARBOR-UCLA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9755205
• 关键词: Acinetobacter baumannii; Affect; Anabolism; Anti-Bacterial Agents; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Bacillus (bacterium); Bacteremia; Bacteria; Binding; Biological Assay; Blood Vessels; CD14 gene; Cell-Matrix Junction; Cells; Cessation of life; Colistin; Communicable Diseases; Complex; Data; Development; Dose; Drug resistance; Edema; Effectiveness; Endothelial Cells; Endotoxemia; Extravasation; Foundations; Frequencies; GTP Binding; Generations; Genes; Goals; Gram-Negative Bacteria; Guanosine Triphosphate Phosphohydrolases; Healthcare Systems; Host Defense Mechanism; Immune response; In Vitro; Incidence; Infection; Infection prevention; Inflammation; Inflammatory; Intercellular Junctions; Interleukin-1 beta; Interleukin-6; Klebsiella pneumonia bacterium; Knockout Mice; Laboratories; Lead; Lipid A; Lipopolysaccharides; Mediating; Methods; Modeling; Monomeric GTP-Binding Proteins; Morbidity - disease rate; Multi-Drug Resistance; Mus; NF-kappa B; Neutrophil Infiltration; Nosocomial Infections; Organ failure; Pathogenesis; Pathway interactions; Patients; Permeability; Personal Satisfaction; Phagocytes; Pharmacology; Phase I Clinical Trials; Pneumonia; Process; Pseudomonas aeruginosa; Research; Resistance; Rodent; Role; Sepsis; Septicemia; Serum; Shock; Signal Transduction; Small Interfering RNA; TLR4 gene; TNF gene; Testing; Tissues; Toxic effect; Toxicology; Vascular Endothelium; Vascular Permeabilities; Virulence; bacterial resistance; cadherin 5; carbapenem resistance; carbapenemase; cytokine; efficacy testing; extensive drug resistance; falls; global health; histopathological examination; immune activation; improved; in vitro activity; in vivo; inhibitor/antagonist; liquid chromatography mass spectrometry; mortality; mouse model; multi-drug resistant pathogen; multidrug-resistant Pseudomonas aeruginosa; novel; outcome forecast; peptide analog; pharmacokinetics and pharmacodynamics; preclinical development; preclinical toxicity; prevent; public health relevance; small molecule inhibitor; tigecycline

 DESCRIPTION (provided by applicant): Multi-drug resistant (MDR) organisms due to Gram negative bacilli (GNB) have become endemic in healthcare systems throughout the world. Of great concern is the recent, remarkable rise in the frequency of extremely drug resistant (XDR)-A. baumannii (AB) infections which increased >17 fold in the last decade. Further, infections with AB are surpassing those caused by Pseudomonas aeruginosa (PA), another MDR GNB, the incidence of which has remained stable across the US. Bloodstream infections caused by XDR AB have >60% mortality rates. Clearly new methods to prevent and treat AB and other MDR GNB are needed. Septicemia is a common manifestation of AB and other GNB infections which is caused by the endotoxic bacterial lipopolysaccharide (LPS) through binding to TLR4. LPS recognition by TLR4 triggers a potent and protective inflammatory cytokine immune response via the MyD88/NF-kB cascade. However, this immune response can often lead to a harmful and frenetic process associated with excess vascular leak that leads to tissue edema, organ failure, shock, and death. We found TLR4 deficient mice to be resistant to AB infection. Consistent with these findings, disruption of LPS synthesis in AB (with LpxC inhibitors affecting lipid A biosynthesis) renders the bacterium totally avirulent in mice despite the lack of in vitro activity of these inhibitors against the bacterium. Recent research by Dr. Dean Li (CSO of Navigen) demonstrated that the excess vascular leak seen in LPS-triggered septicemia is caused by the small GTPase Arf6 which falls in the MyD88/ARNO/Arf6 pathway and functions independently from the MyD88/NF-kB cascade. Arf6 induces vascular endothelium leak via intracellular internalization of VE-cadherin which leads to cell-to-cell junction disruption. We hypothesize that AB bacteremia (and other GNB infections) often fail antibiotic therapy because LPS induces excess vascular leak that results in edema and organ failure. Also, the pharmacological inhibition of Arf6 provides an opportunity to retain the beneficial inflammatory immune response, trigged by TLR4 recognizing LPS, without the added harmful vascular leak. Indeed our preliminary results showed promising activity of one of the Arf6 inhibitors in the mouse model of AB infection. We propose to build on these exciting data to delineate the role of MyD88/ARNO/Arf6 in the pathogenesis of AB infections via siRNA gene inhibition, peptide analogues and knockout mice. Further, we will determine the activity of 2nd generation improved Arf6 inhibitors in treating murine AB infections. Achieving these two goals (R21 aims) will identify 2 lead Arf6 inhibitors for detailed PK/PD and toxicology studies. Finally, we will determine the breadth of activity of these 2 inhibitors against other GNB infections including MDR PA and Klebsiella pneumonia carbapenemase (KPC) in mice (R33 aims). Conclusion of our studies will lay the foundation for further development of Arf6 inhibitors as viable new class of antibiotics versus GNB infections including GMP, GLP preclinical toxicity, and IND filing.

 描述（由申请人提供）：由革兰氏阴性杆菌 (GNB) 引起的多重耐药 (MDR) 微生物已成为全世界医疗保健系统中的流行病。令人高度关注的是最近极端耐药 (XDR)-A 的出现频率显着上升。鲍曼不动杆菌 (AB) 感染在过去十年中增加了 17 倍以上。此外，AB 感染超过了另一种耐多药 GNB 铜绿假单胞菌 (PA) 引起的感染，其发病率在美国各地保持稳定。 XDR AB 引起的血流感染死亡率>60%。显然需要新的方法来预防和治疗 AB 和其他耐多药 GNB。 败血症是 AB 和其他 GNB 感染的常见表现，是由内毒素细菌脂多糖 (LPS) 通过与 TLR4 结合引起的。 TLR4 识别 LPS 通过 MyD88/NF-kB 级联触发有效的保护性炎症细胞因子免疫反应。然而，这种免疫反应通常会导致与过度血管渗漏相关的有害且疯狂的过程，从而导致组织水肿、器官衰竭、休克和死亡。我们发现 TLR4 缺陷小鼠对 AB 感染具有抵抗力。与这些发现一致的是，AB 中 LPS 合成的破坏（LpxC 抑制剂影响脂质 A 生物合成）使该细菌在小鼠体内完全无毒，尽管这些抑制剂缺乏针对该细菌的体外活性。 Dean Li 博士（Navigen 的 CSO）最近的研究表明，LPS 引发的败血症中出现的过度血管渗漏是由小型 GTPase Arf6 引起的，该 GTPase Arf6 属于 MyD88/ARNO/Arf6 通路，并且独立于 MyD88/NF-kB 级联发挥作用。 Arf6 通过 VE-钙粘蛋白的细胞内内化诱导血管内皮渗漏，从而导致细胞间连接破坏。 我们假设 AB 菌血症（和其他 GNB 感染）通常会导致抗生素治疗失败，因为 LPS 会引起过多的血管渗漏，从而导致水肿和器官衰竭。此外，Arf6 的药理学抑制提供了保留由 TLR4 识别 LPS 触发的有益炎症免疫反应的机会，而不会增加有害的血管渗漏。事实上，我们的初步结果表明，其中一种 Arf6 抑制剂在 AB 感染小鼠模型中具有良好的活性。我们建议以这些令人兴奋的数据为基础，通过 siRNA 基因抑制、肽类似物和敲除小鼠来描述 MyD88/ARNO/Arf6 在 AB 感染发病机制中的作用。此外，我们将确定第二代改进的 Arf6 抑制剂在治疗小鼠 AB 感染中的活性。实现这两个目标（R21 目标）将确定 2 种主要的 Arf6 抑制剂，用于详细的 PK/PD 和毒理学研究。最后，我们将确定这 2 种抑制剂针对小鼠中其他 GNB 感染（包括 MDR PA 和肺炎克雷伯菌碳青霉烯酶 (KPC)）的活性广度（R33 目标）。我们的研究结论将为 Arf6 抑制剂的进一步开发奠定基础，作为对抗 GNB 感染的可行的新型抗生素，包括 GMP、GLP 临床前毒性和 IND 备案。