The role of mucin-protein interactions in the innate defense of the lung

描述（由申请人提供）：气道上皮粘膜屏障是强大的先天免疫系统的核心，维持下垫上皮表面。在最广泛的层面上，本提案的主要科学目标是阐明气道凝胶层的组织，气道凝胶层是由称为粘蛋白的非常大的糖蛋白（MUC5B和MUC5AC）与其他保护性生物分子通过不稳定的相互作用形成的，并评估这些相互作用在气道粘液完整性中的作用，作为治疗干预的必要先决条件。我们的假设是，正常的气道粘液是高度结构化的，含有超过100种的蛋白质，这些蛋白质形成了不同的蛋白质复合物，其中许多都围绕着这些粘蛋白。这些复合物构成了一个独立的分泌实体，我们称之为“粘蛋白相互作用组”。我们认为凝胶特性来自于黏液蛋白和蛋白质之间的动态相互作用，这些结构产生了黏液的特定流变特性，使其能够通过咳嗽和血流清除而清除。这一建议将改变黏液蛋白是唯一赋予黏液大部分流变特性的分子的范式，并最终导致对这些相互作用作为肺部先天防御的作用的更好理解。为了验证这些假设，我们使用了广泛的生化、分子和细胞生物学方法，我们建议：1)确定我们的靶蛋白组，显示特异性粘蛋白结合的证据；2)确定黏液-蛋白相互作用所需的结构域；3)评估黏液-蛋白相互作用对黏液表面和整体流变特性的影响。如果这一建议的目标得以实现，它们将增加我们对蛋白质组成与气道分泌物功能之间关系的认识和理解。这些知识是知情治疗干预必不可少的先决条件。

DESCRIPTION (provided by applicant): The airway epithelial mucosal barrier is the heart of a powerful innate immune system that maintains the underlying epithelial surface. At the broadest level, the major scientific goal of this proposal is to elucidate the organization of the airway gel layer, which is formed by very large glycoproteins termed mucins (MUC5B and MUC5AC) coupled with other protective biomolecules through labile interactions, and assess the role of these interactions in airway mucus integrity as an essential pre-requisite for therapeutic intervention. Our hypothesis is that normal airway mucus is highly structured, containing an excess of 100 proteins that form distinct protein complexes many of which are centered around these mucins. These complexes constitute a discrete secretory entity we call the 'mucin interactome'. We propose that gel properties emerge from a dynamic interplay between the mucins and proteins and that these structures engender specific rheological properties of mucus that tune it to removal by cough and flow clearance. This proposal will change the paradigm that mucins are the only molecules that give most of the rheological properties to mucus and will ultimately lead to a greater understanding of the role of these interactions as an innate defense of the lung. In testing these hypotheses, using a broad range of biochemical, molecular and cellular biology methods, we propose: 1) To determine our target panel of proteins that show evidence of specific mucin binding; 2) To determine the domains required for the mucin-protein interactions and 3) To assess the effects of mucin-protein interactions on the surface and bulk rheological properties of the mucus. If the goals of this proposal are achieved, they will increase our knowledge and understanding of the relationship between protein composition and the function of airway secretions. Such knowledge is an essential pre-requisite for informed therapeutic intervention. PUBLIC HEALTH RELEVANCE: This proposal will examine the organization of the airway gel layer formed by very large glycoproteins, termed mucins, coupled to other protective biomolecules through labile interactions, and assess their role on airway mucus integrity and function. This is a novel proposal and will change the paradigm that mucins are the only molecules that give most of the rheological properties to mucus and, if true, will ultimately lead to a greater understanding of the role of these interactions as an innate defense of the lung.