Hair Cell Polarization and Sensory Bundle Development

毛细胞极化和感觉束发育

• 批准号: 10520049
• 负责人: Basile Robin Tarchini
• 金额: $ 66.88万
• 依托单位: JACKSON LABORATORY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-12-01 至 2026-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10520049
• 关键词: Acceleration; Actins; Address; Adult; Affect; Apical; Architecture; Auditory; Binding; Biochemical; Biological Assay; Birth; Cell Culture Techniques; Cell Differentiation process; Cell membrane; Cells; Chemicals; Cochlea; Complex; Cues; Cytoskeleton; Data; Defect; Development; Dimensions; Epidermal Growth Factor Receptor Pathway Substrate 8; Epithelium; Etiology; Failure; Fluorescence Recovery After Photobleaching; Functional Regeneration; Functional disorder; GPSM2 gene; GTP Binding; GTP-Binding Protein Regulators; GTP-Binding Proteins; GTPase-Activating Proteins; Generations; Genes; Genetic; Guanine; Guanine Nucleotide Exchange Factors; Guanine Nucleotides; Guanosine Triphosphate; Hair; Hair Cells; Hearing; Hearing problem; Height; Hydrolysis; Individual; Injections; Intercellular Junctions; Investigation; Knock-in Mouse; Knowledge; Label; Labyrinth; Lateral; Life; Maintenance; Membrane; Mitotic spindle; Molecular; Monitor; Morphogenesis; Motion; Motor; Mouse Strains; Mus; Myosin ATPase; Operative Surgical Procedures; Physiologic pulse; Point Mutation; Polymers; Predisposition; Protein Dynamics; Proteins; Reporter; Research; Role; Scaffolding Protein; Sensorineural Hearing Loss; Sensory; Sensory Hair; Shapes; Side; Signal Transduction; Structure; Syndrome; Tamoxifen; Technology; Testing; Time; Visualization; WHRN gene; Work; apical membrane; congenital hearing loss; deafness; hearing impairment; hearing preservation; in vivo; inducible Cre; mechanical stimulus; mouse model; polarized cell; polymerization; preservation; protein complex; protein function; public health relevance; repaired; small molecule inhibitor; sound; temporal measurement; therapy design; trafficking; vibration

PROJECT SUMMARY/ABSTRACT Deafness at birth frequently originates from defects in the development of sensory cells in the inner ear. Likewise, hearing degradation during life frequently follows damage sustained by these cells after normal development. In each case, a particularly susceptible cellular compartment is the hair bundle, a specialized structure in each sensory cell that detects and relays sound-borne vibrations. The hair bundle is an array of actin-based membrane protrusions, or stereocilia, precisely organized in rows of graded heights. Although the tiered architecture of the hair bundle is fundamental for sensory function, the molecular machinery required for its assembly during development and for the maintenance of its exact dimensions during life remains obscure. To address these open questions, we propose to exploit knowledge gained from our ongoing investigations of the GPSM2-Gαi protein complex in mouse. Absence of the scaffold protein GPSM2 or inhibitory G proteins (Gαi) result in defective hair bundle assembly, a likely etiology for congenital hearing loss in Chudley-McCullough syndrome. The GPSM2-Gαi protein complex is first enriched on one side of the nascent hair bundle only (the bare zone), and then enriched at the tip of stereocilia in the adjacent first row, a distribution required for proper stereocilia placement and elongation, respectively. We showed that the Myosin-15A motor transports GPSM2-Gαi to stereocilia tips, where in turn GPSM2-Gαi increases Myosin-15A amounts compared to other rows to define the tallest identity of the first row. Based on detailed preliminary data, we hypothesize that, 1) As yet unstudied Gαi regulators act as upstream cues to selectively enrich the GPSM2-Gαi complex only in the bare zone region of the apical membrane and only in a single row of stereocilia. 2) Prior GPSM2-Gαi enrichment on one side of the nascent hair bundle is the mechanism by which GPSM2-Gαi becomes restricted to abutting stereocilia in the first row, giving the hair bundle its tiered architecture. 3) Continued enrichment of GPSM2-Gαi at stereocilia tips after development has a role in maintenance of proper stereocilia height and girth in adult hair bundles. To test these hypotheses, we will: 1) Characterize the role of a negative Gαi protein regulator that we already established as a new deafness gene critical for GPSM2-Gαi complex localization and hair bundle morphogenesis. 2) Use a new chemical protein labeling technology and new reporter mouse models to track discrete pools of GPSM2- Gαi and follow their dynamic trafficking to the bare zone and stereocilia tips in time. 3) Inactivate GPSM2-Gαi function in structurally and functionally normal hair bundles in adults, and monitor stereocilia dimensions, stereocilia actin dynamics and mouse auditory function. A thorough understanding of the mechanisms that shape and preserve hair bundles will help interpret and design treatments for sensory cell dysfunction, the principal cause of hearing loss.

项目总结/摘要 出生时耳聋通常是由于内耳感觉细胞发育缺陷造成的。同样地， 在正常发育后，这些细胞受到损伤后，听力在生命中经常退化。在 每种情况下，一个特别敏感的细胞隔室是发束，在每种情况下，一个专门的结构， 检测和传递声音传播的振动的感觉细胞。毛束是一排肌动蛋白基膜 突起或静纤毛，精确地组织成高度分级的行。尽管 毛束是感觉功能的基础，其组装过程中所需的分子机制 在生命过程中，它的发育和维持其确切尺寸的作用仍然不清楚。解决这些 开放性问题，我们建议利用我们正在进行的GPSM 2-Gαi研究中获得的知识 蛋白质复合物。支架蛋白GPSM 2或抑制性G蛋白（Gαi）的缺失导致 毛束组装缺陷：Chudley-McCullough综合征先天性听力损失的可能病因 GPSM 2-Gαi蛋白复合物首先仅在新生毛束的一侧（裸区）富集， 然后在相邻的第一行中的静纤毛尖端处富集，这是适当的静纤毛所需的分布 放置和伸长。我们发现肌球蛋白-15A马达将GPSM 2-Gαi转运到 在静纤毛尖端，与其他行相比，GPSM 2-Gαi反过来增加肌球蛋白-15A的量，以定义 第一行的最高标识。基于详细的初步数据，我们假设：1）尚未研究的Gαi 调节因子作为上游线索，选择性地富集GPSM 2-Gαi复合物，仅在裸区区域， 顶膜和仅在一排静纤毛。2)先前GPSM 2-Gαi富集在 新生毛束是GPSM 2-Gαi限制于邻接静纤毛的机制， 第一排，使头发束的分层结构。3)GPSM 2-Gαi在静纤毛尖端的持续富集 在发育后，在维持成年毛束中适当的静纤毛高度和周长方面起作用。测试 这些假设，我们将：1）表征我们已经建立的负Gαi蛋白调节剂的作用 作为一个新的对GPSM 2-Gαi复合体定位和毛束形态发生至关重要的耳聋基因。2)使用 新的化学蛋白质标记技术和新的报告小鼠模型，以跟踪离散的GPSM 2- Gαi，并及时跟踪它们向裸区和静纤毛尖端的动态运输。3)灭活GPSM 2-Gαi 在成年人的结构和功能正常的发束中发挥作用，并监测静纤毛尺寸， 静纤毛肌动蛋白动力学和小鼠听觉功能。彻底了解形成 和保存头发束将有助于解释和设计感觉细胞功能障碍的治疗方法， 听力损失的原因