Augmenting innate immunity to combat nasal carriage of Staphylococcus aureus

增强先天免疫力以对抗金黄色葡萄球菌的鼻携带

• 批准号: 9241954
• 负责人: ALEXANDER MICHAEL COLE
• 金额: $ 21.9万
• 依托单位: UNIVERSITY OF CENTRAL FLORIDA
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-15 至 2019-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9241954
• 关键词: AIDS/HIV problem; Affinity; Amino Acids; Aminoglycosides; Anabolism; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Bacteria; Binding; Cells; Cessation of life; Clinical; Communities; Complex; Data; Epithelial Cells; Etiology; Genes; Goals; HIV Infections; Hospitalization; Human; Human Genome; Incidence; Individual; Infection; Lead; Mediating; Mupirocin; Nasal Epithelium; Natural Immunity; Natural Resistance; Nonsense Codon; Nose; Nosocomial Infections; Pathogenicity; Pathway interactions; Patients; Peptides; Periodicity; Process; Production; Proteins; RNA Splicing; Reporting; Resistance; Ribosomes; Site; Staphylococcal Infections; Staphylococcus aureus; Structure of mucous membrane of nose; Terminator Codon; Testing; Tissues; Topical Antibiotic; Translations; Work; antimicrobial peptide; bacterial resistance; base; cervicovaginal; combat; combinatorial; extracellular; genetic information; improved; methicillin resistant Staphylococcus aureus; next generation; nonhuman primate; novel strategies; pathogen; premature; prevent; public health relevance; retrocyclin; small molecule; transmission process

 DESCRIPTION (provided by applicant): Staphylococcus aureus (SA) nasal carriage is a common condition in humans that acts as an important reservoir for spreading this pathogen, which causes more deaths each year in the U.S. than HIV/AIDS. Using antibiotics to decolonize the nose of SA, prior to hospitalization, significantly reduces the incidence of nosocomial infection, strongly suggesting that reducing or eliminating nasal carriage of SA would directly lead to a reduction in SA clinical infections. Topical antibiotics such as mupirocin can effectivel rid SA nasal carriage, but repetitive use leads to bacterial resistance. We are proposing a novel approach to reduce nasal carriage of SA, by improving upon the nose's natural immunity against SA. To accomplish this goal, we will restore the production of cyclic antimicrobial peptides called "retrocyclins", which have been evolutionarily silenced in the human genome. While some nonhuman primates produce retrocyclin-like peptides, human retrocyclin genes harbor a premature termination codon that blocks translation of these peptides. Based on the genetic information contained within the otherwise intact retrocyclin genes, we first recreated retrocyclins synthetically, and discovered that retrocyclin peptides are potently active against methicillin-resistant SA (MRSA) strains and all other SA isolates tested, and can work in concert with at least one precursor peptide involved in retrocyclin biosynthesis. In related studies, we restored the natural production of retrocyclin peptides in cervicovaginal cells and tissues using aminoglycosides, which suppressed retrocyclin's premature termination codon, resulting in natural retrocyclin peptides that could protect against HIV infection. We now propose to correct "retrocyclin deficiency" in the nasal mucosa using a next- generation, non-antibiotic, read-through agent called PTC124, which pilot immunocytochemical studies indicate can produce retrocyclins in nasal epithelia. Based on our preliminary studies, we hypothesize that PTC124 will restore the natural production of retrocyclins in the nasal mucosa, and the precursor and mature forms will work in concert to confer sustained protection against SA colonization. Aim 1 will assess the ability of PTC124 to induce anti-SA retrocyclins in human nasal epithelia. We will confirm that human nasal epithelia, treated with PTC124, express intact retrocyclin peptides active against SA, determine the concentration of retrocyclins that is sufficient to protect nasal mucosa from SA colonization, and examine how long a single treatment of PTC124 can maintain retrocyclin-mediated protection. We will then explore which mature and precursor retrocyclins are produced, and where they reside subcellularly and extracellularly. Although there is considerable evidence that mechanisms underlying premature and normal codon termination differ substantially, and suppressing agents should not target normal termination codons, Aim 2 will verify that PTC124 does not induce off-target effects to nasal epithelia. Using agents such as PTC124 to bolster nasal innate immunity would likely reduce the incidence of nasal carriage, and subsequent transmission and infection by SA.

 描述（由申请人提供）：金黄色葡萄球菌（SA）鼻腔携带是人类的一种常见病症，是传播这种病原体的重要储存库，在美国每年造成的死亡人数比使用抗生素消除艾滋病毒/艾滋病的人数还要多。在显着住院之前，鼻腔携带SA可降低院内感染的发生率，这强烈表明减少或消除鼻腔携带SA将直接导致SA临床感染的减少，例如外用抗生素。莫匹罗星可以有效消除鼻腔SA，但重复使用会导致细菌耐药性。我们提出了一种通过提高鼻子对SA的天然免疫力来减少鼻腔SA的新方法。为了实现这一目标，我们将恢复SA的产生。称为“逆环素”的环状抗菌肽，在人类基因组中进化产生沉默，虽然一些非人类灵长类动物具有逆环素样肽，但人类逆环素基因具有阻止提前终止的密码子。基于这些肽的翻译，我们首先合成了逆环素基因，并发现逆环素肽对耐甲氧西林 SA (MRSA) 菌株和所有其他测试的 SA 分离株具有有效活性。在相关研究中，我们恢复了宫颈阴道细胞中逆环素肽的自然产生。和使用氨基糖甙类药物的组织，其抑制逆转录酶的过早终止密码子，从而产生可以预防艾滋病毒感染的天然逆转录酶肽，我们现在建议使用下一代非抗生素通读来纠正鼻粘膜中的“逆转录酶缺乏症”。 PTC124 是一种名为 PTC124 的药物，初步免疫细胞化学研究表明它可以在鼻上皮细胞中产生逆转录环素。根据我们的初步研究，我们发现 PTC124 可以恢复自然状态。目标 1 将评估 PTC124 在人鼻上皮细胞中诱导抗 SA 逆转录酶的能力。用 PTC124 处理的鼻上皮，表达对 SA 有活性的完整逆转录环素肽，确定足以保护鼻粘膜免受 SA 定植的逆转录环素浓度，并检查如何PTC124 的单次治疗可以维持逆转录酶介导的保护，然后我们将探索产生哪些成熟和前体逆转录酶，以及它们在细胞内和细胞外的位置。并且抑制剂不应针对正常终止密码子，目标 2 将验证 PTC124 不会对鼻上皮细胞产生脱靶效应。可能会减少鼻腔携带的发生率以及随后的 SA 传播和感染。