Project 4: Biophysical and structural characterization of airway submucosal gland mucus in health and disease

项目4：健康和疾病中气道粘膜下腺粘液的生物物理和结构特征

• 批准号: 10684217
• 负责人: Ronit Freeman
• 金额: $ 38.87万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-15 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10684217
• 关键词: Affect; Air; Bicarbonates; Binding; Biophysics; Bundling; Calcium; Cell surface; Charge; Chelating Agents; Cilia; Complement; Coughing; Coupled; Defect; Devices; Diameter; Dimensions; Disease; Duct (organ) structure; Encapsulated; Engineering; Epithelium; Exhibits; Failure; Family suidae; Functional disorder; Gel; Gland; Goals; Health; Host Defense; Human; Inhalation; Investigation; Ions; Irritants; Length; Liquid substance; Lung; MUC5AC gene; MUC5B gene; Mediating; Microfluidics; Modeling; Mucins; Mucociliary Clearance; Mucous body substance; Peptides; Peripheral; Prevalence; Process; Property; Proteins; Relaxation; Resolution; Role; Saline; Side; Stretching; Structure; Submucosa; Surface; System; Testing; Width; aspirate; cholinergic; fluid flow; lung health; meter; mimetics; novel; particle; prevent; respiratory; response; sugar; surfactant

Abstract The contribution of submucosal gland (SMG) mucus to the host defense functions of airway surfaces is not well understood. SMG mucus emerges from the SMG onto airway surfaces in the form of micron long bundles. However, it is unknown how SMG mucus bundles are formed, what regulates their structure, and what is their functional role. The minimal understanding of SMG mucus structure has limited our ability to predict how SMG mucus promotes lung health and contributes to disease. The prevalence of SMGs in the proximal airways suggests SMG mucus defense functions include clearing large, aspirated, or inhaled particles by cough. However, understanding how SMG bundles are configured for this role requires a comprehensive characterization of SMG gland mucus as well as engineering of novel models to elucidate the mechanisms of SMG bundle formation. We have identified three key gaps in our understanding of the structure and function/dysfunction of SMG mucus for investigation, encapsulated in our three specific aims. Specific Aim 1: Do SMGs secrete a different mucus in basal versus stimulated conditions? This aim will test the hypothesis that SMG basal secretions constitute a soluble gel that dissolves into the air surface liquid, whereas stimulated SMG secretions consists of both soluble and insoluble fractions, the insoluble component constituting a “permanent” mucus bundle. Specific Aim 2: How do SMG bundles form and what is their functional role? This aim will engineer gland mimetic systems to test the hypothesis that glands are configured to produce strong fluid flows to extrude bundles in a two-level hierarchical process involving primary strand formation by mucin stretching and sticking through open globular domains in peripheral gland ‘nozzle’ junctions, followed by their extrusion as bundles through the ciliated duct nozzle. This aim will also test how bundles are configured to bind and clear large particles by cough. Specific Aim 3: How and why SMGs fail in CF? This aim will test the hypothesis that reduced fluid flows in the CF SMG is the critical failure, generating insufficient mucin extensional forces, producing disorganized mucus bundles that stick to cell surfaces and reduce cilia-dependent transport. Resolution of the hypotheses advanced in this proposal will establish a new paradigm of how glands produce mucus bundles in response to stimulation and complement superficial epithelial responses to clear large irritants by cough.

摘要 粘膜下腺（SMG）粘液对气道表面宿主防御功能的贡献不是 很好理解。SMG粘液以微米长的束的形式从SMG出现在气道表面上。 然而，尚不清楚SMG粘液束是如何形成的，是什么调节它们的结构，以及它们的结构是什么。 功能作用。对SMG粘液结构的最低限度的了解限制了我们预测SMG 粘液促进肺部健康并导致疾病。近端气道SMG的患病率 表明SMG粘液防御功能包括清除咳嗽时吸入或吸入的大颗粒。 但是，要了解如何为该角色配置SMG捆绑包， SMG腺粘液的表征以及新模型的工程化以阐明机制 SMG束的形成。 我们已经确定了我们对SMG结构和功能/功能障碍的理解中的三个关键差距 我们的三个具体目标具体目标1：SMG是否分泌不同的 基础与刺激条件下的粘液？这一目的将检验SMG基础分泌物 构成溶解到空气表面液体的可溶性凝胶，而刺激的SMG分泌物构成 可溶性和不溶性组分，不溶性组分构成“永久性”粘液束。 具体目标2：SMG束如何形成，它们的功能作用是什么？这一目标将工程腺体 模拟系统，以测试假设，腺体被配置为产生强大的流体流，以挤出 束在两个层次的过程中，涉及初级链的形成粘蛋白拉伸和粘附 通过开放的球状域在外围腺'喷嘴'连接，其次是他们的挤压作为束 通过纤毛导管喷嘴这一目标还将测试如何配置bundle来绑定和清除大型 咳嗽颗粒。具体目标3：SMG如何以及为什么在CF中失败？这一目标将检验以下假设： CF SMG中减少的流体流动是关键故障，产生的粘蛋白伸展力不足， 产生混乱的粘液束，粘在细胞表面，减少纤毛依赖的运输。 在这个建议中提出的假设的决议将建立一个新的范例，如何腺体 产生粘液束以响应刺激并补充浅表上皮反应以清除 咳嗽引起的大的刺激物。