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）微生物已成为全球医疗保健系统的地方病。令人非常关注的是最近极端耐药（XDR）-A的频率显着上升。鲍曼不动杆菌（AB）感染在过去十年中增加了>17倍。此外，AB的感染超过了铜绿假单胞菌（PA）引起的感染，PA是另一种MDR GNB，其发病率在美国保持稳定。由XDR AB引起的血流感染具有>60%的死亡率。显然，需要新的方法来预防和治疗AB和其他MDR GNB。 败血症是AB和其他GNB感染的常见表现，其由内毒素细菌脂多糖（LPS）通过与TLR 4结合而引起。TLR 4对LPS的识别通过MyD 88/NF-kB级联反应触发了有效的保护性炎症细胞因子免疫应答。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和狂热的过程，导致组织水肿、器官衰竭、休克和死亡。我们发现TLR 4缺陷小鼠对AB感染具有抗性。与这些发现一致，AB中LPS合成的破坏（用影响脂质A生物合成的LpxC抑制剂）使得细菌在小鼠中完全无毒，尽管这些抑制剂缺乏针对细菌的体外活性。Dean Li博士（Navigen的CSO）最近的研究表明，在LPS触发的败血症中观察到的过量血管渗漏是由小GTd 6 Arf 6引起的，小GTd 6 Arf 6福尔斯位于MyD 88/ARNO/Arf 6通路中，其功能独立于MyD 88/NF-kB级联反应。Arf 6通过VE-钙粘蛋白的细胞内化诱导血管内皮渗漏，导致细胞间连接破坏。 我们假设AB菌血症（和其他GNB感染）通常抗生素治疗失败，因为LPS诱导过度的血管渗漏，导致水肿和器官衰竭。此外，Arf 6的药理学抑制提供了保留由识别LPS的TLR 4所引起的有益的炎症免疫应答的机会，而没有增加有害的血管渗漏。实际上，我们的初步结果显示了Arf 6抑制剂之一在AB感染的小鼠模型中的有希望的活性。我们建议建立在这些令人兴奋的数据，描绘的作用MyD 88/ARNO/Arf 6通过siRNA基因抑制，肽类似物和敲除小鼠在AB感染的发病机制。此外，我们将确定第二代改进的Arf 6抑制剂在治疗鼠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Arf 6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种抑制剂对其他GNB感染（包括MDR PA和肺炎克雷伯菌碳青霉烯酶（KPC））在小鼠中的活性范围（R33 aims）。我们的研究结论将为进一步开发Arf 6抑制剂作为对抗GNB感染的可行的新型抗生素奠定基础，包括GMP，GLP临床前毒性和IND申请。