Nanotherapeutics for Ocular Infections

 描述（由申请人提供）：眼部细菌感染在全球范围内导致大量失明病例。在感染过程中防止脆弱的眼组织损伤的努力依赖于迅速和适当地使用治疗剂来快速杀死生物体并阻止潜在的破坏性炎症。目前使用的抗生素可以杀死生物体，但抗炎药的有效性是有争议的。这些药物类别不针对感染部位细菌合成的组织损伤毒素。孔形成毒素（PFT）是重要的，往往是必不可少的，以下革兰氏阳性眼部病原体的眼部毒力：金黄色葡萄球菌，肺炎链球菌，蜡样芽孢杆菌，粪肠球菌。当PFT不存在时，眼部毒力显著降低。新的PFT靶向治疗剂，中和跨物种的毒素，将提供覆盖最常见的革兰氏阳性病原体引起眼表（角膜炎）和眼内（眼内炎）感染。毒素中和作为抗生素和抗炎剂的辅助将提供对组织损伤毒素无效的当前疗法的显著改善。 最近已经开发了靶向革兰氏阳性PFT的纳米海绵。在体外，纳米海绵中和革兰氏阳性PFT。在脓毒症和组织感染的体内实验模型中，纳米海绵可以中和感染部位的毒素并降低毒力。我们假设纳米海绵可以有效地降低眼部环境中细菌PFT的毒性活性，从而用作与抗生素一起治疗眼内和眼表感染的新型抗毒素治疗剂。初步数据表明了检验我们假设的可行性。我们表明，纳米海绵1）中和革兰氏阳性眼部病原体的PFT，2）在泪液，玻璃体和抗生素的存在下这样做，3）防止毒性眼细胞死亡，以及4）在小鼠眼睛中/上无毒。 眼部细菌感染临床改善的关键障碍是缺乏毒素靶向。我们将测试纳米海绵的PFT中和活性和抗生素对引起角膜炎（Aim 1）和眼内炎（Aim 2）的眼部病原体的有效性，并将研究其在眼部应用后的生物分布（Aim 3）。如果纳米海绵是有效的，下一步是用更有效的抗生素和更好的抗炎剂测试纳米海绵。纳米海绵在治疗眼部细菌感染中的测试是高风险的，但是是新颖的、高影响的、预防性相关的，并且将通过鉴定可以在感染期间保护眼睛的脆弱组织的新颖抗毒素疗法而对眼部感染性疾病领域产生积极影响。拟议的研究是我们眼部感染研究项目的逻辑结果，我们有能力提供有价值的信息，为医生提供最佳的治疗方案，以在眼部感染期间保护视力。

 DESCRIPTION (provided by applicant): Ocular bacterial infections cause a significant number of cases of blindness worldwide. Efforts to prevent damage to delicate ocular tissues during infection rely on swift and proper use of therapeutics to rapidly kill organisms and arrest potentially damaging inflammation. Currently-used antibiotics can kill organisms, but the effectiveness of anti-inflammatory drugs is controversial. These drug classes do not target tissue-damaging toxins synthesized by bacteria at the site of infection. Pore-forming toxins (PFTs) are important, and often essential, to ocular virulence of the following Gram-positive ocular pathogens: Staphylococcus aureus, Streptococcus pneumoniae, Bacillus cereus, and Enterococcus faecalis. When PFTs are absent, ocular virulence is significantly decreased. Novel PFT-targeting therapeutics which neutralize toxins across species would provide coverage for the most common Gram-positive pathogens causing ocular surface (keratitis) and intraocular (endophthalmitis) infections. Toxin neutralization as an adjunct with antibiotics and anti-inflammatory agents would provide a significant improvement over current therapies that are ineffective against tissue-damaging toxins. Nanosponges have recently been developed which target Gram-positive PFTs. In vitro, nanosponges neutralize Gram-positive PFTs. In in vivo experimental models of sepsis and tissue infection, nanosponges neutralize toxins at the site of infection and reduce virulence. We hypothesize that nanosponges can effectively reduce the toxic activity of bacterial PFTs in the ocular environment, leading to use as a novel anti-toxi therapeutic with antibiotics for the treatment of intraocular and ocular surface infections. Preliminary data demonstrates the feasibility of testing our hypothesis. We show that nanosponges 1) neutralize PFTs of Gram-positive ocular pathogens, 2) do so in the presence of tears, vitreous, and antibiotics, 3) protect against toxic ocular cell death, and 4) are not toxic in/on mouse eyes. A critical barrier to clinical improvements in ocular bacterial infections is th absence of toxin- targeting. We will test nanosponges for PFT-neutralizing activity and efficacy with antibiotics against ocular pathogens causing keratitis (Aim 1) and endophthalmitis (Aim 2), and will also investigate their biodistribution following ocular application (Aim 3). If nanosponge are effective, the next step is to test nanosponges with more potent antibiotics and better anti-inflammatory agents. Testing of nanosponges in the treatment of ocular bacterial infections is high risk, but is novel, high-impact, translationally relevant, and will positively influence the ocular infectious disease field by identifying a novel anti-toxin therapy which may protect delicate tissues of the eye during infection. The proposed studies are a logical outgrowth of our ocular infection research program, and we are well positioned to contribute valuable information which will provide physicians with the best possible therapeutic options to preserve vision during ocular infections.