Novel Therapeutic Target(s) for Pathogenic Rickettsia Species

致病性立克次体的新治疗靶点

• 批准号: 9041781
• 负责人: Abha Sahni
• 金额: $ 23.25万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9041781
• 关键词: Adhesions; Affect; Affinity; Americas; Antibodies; Binding; Biological Markers; Blood; Boutonneuse Fever; Brain; Case Fatality Rates; Cell Adhesion; Cell Culture System; Cell surface; Cells; Cerebral Edema; Cerebrum; Communicable Diseases; Complex; Cytoplasm; Data; Development; Diagnosis; Diagnostic; Disease; Disease Outcome; Disease Progression; Dose; Drug Targeting; Early Diagnosis; Endocytosis; Endothelial Cells; Endothelium; Ensure; Environment; Exploratory/Developmental Grant; FGF2 gene; Fever; Fibroblast Growth Factor; Fibroblast Growth Factor Receptor 1; Fibroblast Growth Factor Receptors; G22P1 gene; Gene Expression; Goals; Gram-Negative Bacteria; Growth; Growth Factor Interaction; Heparan Sulfate Proteoglycan; Heparin Lyase; Human; In Vitro; Infection; Inflammation; Integrins; Interstitial Pneumonia; Invaded; Knockout Mice; Life Cycle Stages; Ligands; Lung; Measures; Mediating; Membrane Proteins; MicroRNAs; Mission; Molecular; Molecular Profiling; Morbidity - disease rate; Mus; Nutrient; Oral Administration; Organ; Outcome; Pathogenesis; Patients; Permeability; Phase II Clinical Trials; Phosphorylation; Plasma; Regulation; Research; Rickettsia; Rickettsia rickettsii; Rocky Mountain Spotted Fever; Role; Signal Transduction; Small Interfering RNA; Spottings; Symptoms; System; Testing; Therapeutic; Ticks; Tissues; Tropism; United States National Institutes of Health; Ursidae Family; Vascular Permeabilities; Vascular System; Vasculitis; Work; cell injury; cell motility; defined contribution; diagnostic biomarker; flu; human disease; in vivo; indexing; inhibitor/antagonist; innovation; mortality; mouse model; new therapeutic target; novel; novel diagnostics; novel marker; novel strategies; novel therapeutic intervention; novel therapeutics; obligate intracellular parasite; pathogen; prevent; public health relevance; receptor; screening; small molecule inhibitor; tool; transcriptome sequencing; transcriptomics; vascular inflammation

 DESCRIPTION (provided by applicant): Rocky Mountain spotted fever (RMSF) due to tick-transmitted Rickettsia rickettsii is a serious infectious disease prevalent in the Americas. R. conorii, the etiologic agent of Mediterranean spotted fever phylogenetically related to R. rickettsii, can also cause debilitating human infections associated with significant morbidity and mortality. Pathogenic rickettsiae preferentially target microvascular endothelium of small- and medium-sized vessels resulting in vascular inflammation and compromised permeability, collectively termed as `rickettsial vasculitis'. As obligate intracellular pathogens, efficient adhesion and invasion into host cells followed by quick escape into nutrient-rich cytoplasmic niche is critical for rickettsial growth, replication, and dissemination. Through a combination of complementary approaches, we have recently discovered Fibroblast Growth Factor Receptor 1 (FGFR1) as one of the receptors utilized by rickettsiae to gain entry into host endothelial cells. Further evidence from our ongoing work clearly suggests that inhibition of FGFR1 diminishes the levels of intracellular infection in vitro and pulmonary rickettsial burden in vivo. Mechanistically, negative regulation of two host-specific microRNAs (miR424 and miR503) results in augmented expression of FGFR1 to facilitate interactions between the host cell and invading rickettsiae. The overall objective of this application is to exploit this critical `initia' interaction of pathogenic rickettsiae with the target host cells, the blocking of which prevents entry and access to intracytoplasmic environment conducive to their growth and replication, for the development of new therapeutic strategies and identification of potentially novel biomarkers for early diagnosis. Accordingly, we propose to investigate the contributions of and mechanisms underlying host miR-mediated regulation of FGF2/FGFR1 expression in the invasion of human and mouse microvascular endothelium by SF rickettsiae in vitro [Aim 1] . Specifically, we will determine the effects of miR424/miR503 mimics and antagomirs as well as FGFR1-specific inhibitors on FGF2/FGFR1 expression and rickettsial invasion and elucidate the mechanisms underlying FGFR1-mediated entry. We will next delineate the contributions of FGF2/FGFR1 interactions in the initiation and progression of RMSF in established mouse models and explore the potential for FGFR1 inhibitors and miR424/503 mimics as novel therapeutics and circulating miRs as early biomarkers of disease [Aim 2] . The multi-disciplinary approaches to accomplish these aims will not only involve physiologically relevant human and murine cell culture systems, established mouse models of infection closely recapitulating human disease, and cutting-edge applications of cellular and molecular transcriptomics, but will also benefit from endothelial-specific disruption of FGFR1 in mice and strong institutional expertise in all aspects of Rickettsiology research. This proposal is highly relevant to the mission of the NIH, as it aims to uncover novel targets to develop new therapeutics and identify new tools for the diagnosis of severe and potentially fatal rickettsioses afflicting human-kind across the globe.

 描述(申请人提供)：由立克次体引起的落基山斑点热(RMSF)是一种流行于美洲的严重传染病。康氏立克次体是地中海斑点热病的病原体，与立克次体有亲缘关系，也可引起与显著发病率和死亡率相关的衰弱的人类感染。致病性立克次体优先攻击中小血管的微血管内皮细胞，导致血管炎症和通透性受损，统称为立克次体血管炎。作为特有的细胞内病原体，有效的黏附和入侵宿主细胞，然后快速逃逸到营养丰富的细胞质生态位对立克次体的生长、复制和传播至关重要。通过多种互补手段的结合，我们最近发现成纤维细胞生长因子受体1(FGFR1)是立克次体进入宿主内皮细胞的受体之一。来自我们正在进行的工作的进一步证据清楚地表明，抑制FGFR1在体外减少了细胞内感染的水平，在体内减少了肺立克次体负担。从机制上讲，两个宿主特异的microRNAs(miR424和miR503)的负调控导致FGFR1表达增强，以促进宿主细胞和入侵立克次体之间的相互作用。这一应用的总体目标是利用致病立克次体与目标宿主细胞的这一关键的“初始”相互作用，阻止其进入和进入有利于其生长和复制的细胞质内环境，以开发新的治疗策略和识别潜在的新的早期诊断生物标志物。因此，我们建议研究宿主miR介导的FGF2/FGFR1表达调控在立克次体体外侵袭人和小鼠微血管内皮细胞中的作用和机制[目的1]。具体地说，我们将确定miR424/miR503模拟物和抗原物以及FGFR1特异性抑制剂对FGF2/FGFR1表达和立克次体侵袭的影响，并阐明FGFR1介导的进入的机制。接下来，我们将描述FGF2/FGFR1相互作用在已建立的小鼠模型中RMSF的启动和进展中的作用，并探索FGFR1抑制剂和miR424/503模拟物作为新的治疗药物和循环中的miR作为疾病早期生物标记物的潜力[目标2]。实现这些目标的多学科方法不仅涉及与生理相关的人类和小鼠细胞培养系统，建立的与人类疾病相似的感染小鼠模型，以及细胞和分子转录组学的前沿应用，而且还将受益于小鼠内皮细胞特异性的FGFR1干扰，以及在Rickettology研究的所有方面的强大机构专业知识。这项建议与美国国立卫生研究院的使命高度相关，因为它旨在发现新的目标，以开发新的治疗方法，并确定新的工具来诊断困扰全球人类的严重和潜在致命的立克次体病。