Eph-ephrin signaling in the lens

晶状体中的肝配蛋白信号传导

• 批准号: 10585924
• 负责人: Catherine Kehsin Cheng
• 金额: $ 46.46万
• 依托单位: TRUSTEES OF INDIANA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10585924
• 关键词: Affect; Age; Aging; Agonist; Anterior; Biochemical; Biomechanics; Blindness; Cataract; Cell Adhesion Molecules; Cell Communication; Cell Differentiation process; Cell Maturation; Cell Nucleus; Cell membrane; Cell-Cell Adhesion; Cells; Confocal Microscopy; Crystalline Lens; Cytoskeleton; Data; Development; Disease; Electron Microscopy; Eph Family Receptors; EphA2 Receptor; Ephrin-A5; Ephrins; Epithelial Cells; Fiber; Functional disorder; Glass; Goals; Growth; Homeostasis; Human; Immunofluorescence Immunologic; In Vitro; Knock-out; Lead; Lens Opacities; Lens development; Ligand Binding; Ligands; Link; Maps; Mass Spectrum Analysis; Measures; Mediating; Molecular; Morphology; Mus; Mutation; Normal Cell; Nuclear; Nutrient; Optics; Pathology; Pathway interactions; Patients; Pattern; Peptides; Peripheral; Phosphorylation; Phosphotransferases; Play; Population; Presbyopia; Property; Reading; Refractive Indices; Reporting; Role; Serine; Shapes; Signal Pathway; Signal Transduction; Signaling Molecule; Structure; Tissues; Tyrosine; Vision; Visual impairment; Work; World Health Organization; age related; antagonist; epithelial to mesenchymal transition; fiber cell; in vitro Model; lens; lens cortex; lens transparency; mouse model; normal aging; prevent; receptor; segregation; superresolution microscopy; ultra high resolution; wasting

Project Summary According to the World Health Organization, age-related lens pathologies are the leading cause of visual impairment in the world. Cataracts, defined as any opacity in the eye lens, remain the leading cause of blindness in the world. Presbyopia is caused by a reduction in the lens’ ability to change shape during focusing (accommodation), and, by extension, the need for reading glasses. Unaddressed presbyopia is the leading cause of visual impairment globally. Decades of study have focused on congenital lens pathologies, and thus, very little is known about the underlying cellular and molecular mechanisms that facilitate lifelong lens homeostasis. Recent studies have reported that mutations of the EphA2 receptor or the ephrin-A5 ligand are associated with variable congenital and age-related cataracts in humans and mice, and these bidirectional signaling molecules are key components for regulating lens cell organization and stability. Our mouse models reveal that loss of EphA2 leads to age-related cortical cataracts similar to human patients with EphA2 dysfunction. We will evaluate cataract progression in our mouse line to study the cellular and molecular changes that occur during cortical cataract formation. We hypothesize that loss of EphA2 results in changes in cytoskeletal structures or cell-cell adhesion of peripheral fiber cells leading to optical discontinuities in the lens cortex. Our new data show that the lens utilizes both canonical ligand-mediated EphA2 bidirectional signaling and non-canonical ligand-independent EphA2 signaling pathways. We hypothesize that canonical EphA2 signaling is required in equatorial epithelial cells while non-canonical EphA2 activation is required for fiber cell differentiation and maturation and that this segregation of receptor activity may explain the large variety of human congenital and age-related cataracts caused by EphA2 mutations. We will evaluate the activation pattern of EphA2 spatially and temporally and determine the activity of known downstream pathways in different lens cell populations. We will apply EphA2 agonist and antagonist peptides to primary culture mouse lens epithelial cells to generate mini lenses as an in vitro model for lens development. Increased size and stiffness of the lens center or nucleus has been hypothesized to be a key factor for not only age-related increases in overall lens stiffness and presbyopia, but also poor nutrient and waste transport leading to age-related nuclear cataracts. Our new preliminary data shows that loss of EphA2 leads to softer, smaller lens nuclei. We hypothesize that Eph-ephrin signaling is required for normal cell-cell adhesion and cytoskeleton rearrangement that drives nuclear fiber cell membrane re-organization and compaction. This data will provide a better understanding of coordinated signaling mechanisms for maintaining homeostasis during normal aging and in lenses with changes in transparency and biomechanical properties, which may lead to the development of new non-surgical approaches to delay or prevent age-related lens pathologies.

项目摘要 根据世界卫生组织的说法，与年龄相关的镜头病理是视觉的主要原因 世界上的损害。白内障被定义为眼镜中的任何不透明度，仍然是 世界上的失明。长老会是由于镜头在聚焦期间改变形状的能力的降低引起的 （住宿），并扩展需要阅读眼镜。未解决的长老会是领先的 全球视觉障碍的原因。数十年的研究集中于先天性晶状体病理，因此 关于促进终身镜头的基本细胞和分子机制知之甚少 稳态。最近的研究报告说，埃法2受体或ephrin-A5配体的突变是 与人类和小鼠的先天性和年龄相关性白内障相关，这些双向 信号分子是调节晶状体细胞组织和稳定性的关键组成部分。 我们的小鼠模型表明，EPHA2的损失导致与人类类似的年龄相关的皮质白内障 EPHA2功能障碍的患者。我们将评估小鼠系中的白内障进展以研究细胞 和皮质白内障形成过程中发生的分子变化。我们假设EPHA2结果的丢失 在周围纤维细胞的细胞骨架结构或细胞细胞粘附的变化中，导致光学 镜头皮质中的不连续性。 我们的新数据表明，镜头都使用了两种规范配体介导的Epha2双向信号传导和 非典型配体无关EPHA2信号通路。我们假设规范EPHA2信号传导 纤维细胞需要非典型的EPHA2激活，而非典型的EPHA2激活是需要的 分化和成熟，并且接收器活动的这种隔离可能解释了各种各样的种类 由Epha2突变引起的人类先天性和与年龄有关的白内障。我们将评估激活 以epha2的模式在空间和临时确定已知下游途径的活性 不同的晶状体细胞种群。我们将将Epha2激动剂和拮抗剂肽应用于原代培养小鼠 晶状体上皮细胞生成迷你镜片作为晶状体发育的体外模型。 假设镜头中心或核的尺寸和刚度增加是不可能的关键因素 只有与年龄相关的整体镜头刚度和老花眼的增加，但营养和废物运输也很差 导致与年龄有关的核白内障。我们的新初步数据表明，Epha2的损失导致较柔软， 较小的透镜核。我们假设正常细胞 - 细胞粘合剂和 驱动核纤维细胞膜重组和压实的细胞骨架重排。这个数据 将更好地理解协调的信号传导机制，以维持稳态的稳态 正常衰老和透镜中的透明度和生物力学特性变化，这可能导致 开发新的非手术方法，以延迟或预防与年龄相关的透镜病理。