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: 9488843
• 负责人: ASHRAF S. IBRAHIM
• 金额: $ 45.71万
• 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 2020-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9488843
• 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; 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; killings; liquid chromatography mass spectrometry; mortality; mouse model; multi-drug resistant pathogen; multidrug-resistant Pseudomonas aeruginosa; novel; outcome forecast; peptide analog; 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.