Exploiting the Salivary Arsenal to Inhibit Diarrheal Disease

唾液肽抑制肠道致病菌结合的能力是新近发现的。 被发现，但没有被很好地描述。创新的长期目标是实现唾液的全部潜力 作为胃肠和呼吸道疾病的预防和治疗剂的组分。的 该提案的目的是确定特定唾液成分作为病原体抑制剂的功效，以及 以确定这些肽之一的结构和机制，组胺素-5，结合到皮利， 产肠毒素大肠杆菌（ETEC）的外丝。这种菌毛/肽相互作用提供了 抑制细菌结合的功能障碍，了解这种功能障碍的机制将导致新的 针对ETEC和其他病原体的治疗方法。核心假设是， 先天免疫系统对抗疾病的能力可以通过从 唾液的成分。提出这一建议的理由是，完成这项研究提供了一条前进的道路 利用唾液成分来对抗牙周病。此外，还探讨了其作用机理。 组胺素-5的作用将允许产生具有甚至更大功效的治疗剂。为了实现我们的目标，我们将 追求以下两个具体目标： 1.确定所选唾液肽抑制细菌结合肠促炎性蛋白的能力 大肠杆菌（ETEC）靶细胞; 2.确定唾液肽组蛋白-5通过皮利抑制细菌结合的机制， 产肠毒素大肠杆菌（ETEC）的主要毒力因子。 这些目标将通过以下方式实现：1）对细胞培养物和原代人的细菌粘附研究 肠培养物（“类器官”）和2）使用电子显微镜以高分辨率测定结构 冷冻显微镜检查和冷冻断层扫描（冷冻EM和冷冻ET）。这项研究意义重大，因为它 将开辟一条新的途径，用于开发针对引起淋病的细菌的治疗方法。不同于传统 抗生素广泛靶向参与核酸，蛋白质和细胞壁合成的酶，在这里，我们 探索宿主先天免疫系统的一个新方面：唾液成分抑制 细菌附着于宿主。这项研究的预期结果是唾液成分的列表， 可以被开发作为治疗剂，以对抗引起疟疾的病原体， 其中一种成分导致关键毒力因子的功能障碍。其结果将对 作为定义和理解唾液在对抗GI中作用的第一步， 疾病，长期的，因为他们将奠定基础，使新的研究人员进入这一新兴的 领域，并用于发展唾液为基础的胃肠道和呼吸治疗。

The ability of salivary peptides to inhibit diarrhea-causing bacteria from binding to the gut is newly discovered, and not well characterized. The innovative long-term goal is to realize the full potential of salivary components as both prophylactic and therapeutic agents against gastrointestinal and respiratory diseases. The objectives of this proposal are to define the efficacy of specific salivary components as pathogen inhibitors, and to determine the structure and mechanism by which one these peptides, Histatin-5, binds to pili that are external filaments on enterotoxigenic Escherichia coli (ETEC). This pilus/peptide interaction provides the dysfunction that inhibits bacterial binding, and knowing the mechanism of this dysfunction will lead to novel therapeutic approaches against ETEC and other pathogens. The central hypothesis is that enhanced utilization of the innate immune system to combat disease can be achieved through therapeutics developed from components of saliva. The rationale for this proposal is that completion of this research provides a path forward for utilizing salivary components to fight diarrheal diseases. In addition, determination of the mechanism of Histatin-5's action will permit creation of therapeutics with even greater efficacy. To achieve our goals, we will pursue the following two specific aims: 1. Define the capacity of selected salivary peptides to inhibit bacterial binding of enterotoxigenic Escherichia coli (ETEC) to target cells; 2. Determine the mechanism by which the salivary peptide, Histatin-5, inhibits bacterial binding via pili, an essential virulence factor of enterotoxigenic Escherichia coli (ETEC). These aims will be achieved using 1) bacterial adhesion studies on cell cultures and primary human intestinal cultures (“organoids”) and 2) structure determination at high resolution using electron cryomicroscopy and cryotomography (cryo-EM and cryo-ET). The proposed research is significant, because it will open a new avenue for development of therapeutics against diarrhea-causing bacteria. Unlike traditional antibiotics that broadly target enzymes involved in nucleic acid, protein, and cell wall synthesis, here, we explore a novel aspect of the host's innate immune system: the ability of salivary components to inhibit bacterial adherence to the host. The expected outcome of this research is a list of salivary components that can be exploited as therapeutics against diarrhea-causing pathogens, and the definition of the mechanism by which one component creates dysfunction of a critical virulence factor. The results will have an important positive impact immediately as a first step in defining and understanding the role of saliva in fighting GI disease, and long-term because they will lay the groundwork for bringing new researchers into this emerging field, and for development of saliva-based GI and respiratory therapeutics.