Role of mechanosensation in retinal function and dysfunction

机械感觉在视网膜功能和功能障碍中的作用

基本信息

批准号：
8586264
负责人：
DAVID KRIZAJ
金额：
$ 36.51万
依托单位：
UNIVERSITY OF UTAH
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-12-01 至 2016-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8586264
关键词：
Apoptosis Astrocytes Blindness Calcium Calcium Channel Calcium Oscillations Calcium Signaling Cations Cell Survival Cell Volumes Cell membrane Cell physiology Cells Cellular Membrane Chronic Clinical Complex Diabetes Mellitus Diabetic Retinopathy Disease Edema Effectiveness Equilibrium Etiology Eye diseases Functional disorder Glaucoma Glutamate Receptor Glutamates Goals Homeostasis Hydrostatic Pressure In Vitro Injury Ion Channel Ischemia Light Link Mechanical Stimulation Mechanical Stress Mechanics Mediating Membrane Modeling Molecular Muller&apos s cell Mus Nerve Degeneration Neuroglia Neurons Pathology Patients Physiologic Intraocular Pressure Physiological Play Preparation Process Property Regulation Research Research Project Grants Retina Retinal Retinal Edemas Retinal Ganglion Cells Risk Factors Role Signal Transduction Speed Stimulus Stress Stretching Swelling Techniques Testing Traumatic Brain Injury Vision Disorders Work base cell injury cell type cellular transduction cohort desensitization excitotoxicity experience in vivo insight knockout animal macular edema mouse model nervous system disorder neuroprotection neurotoxic optic nerve disorder painful neuropathy pressure public health relevance research study response retinal neuron small molecule translational approach water channel

项目摘要

DESCRIPTION (provided by applicant): Glaucoma is complex of devastating blinding diseases that together represent the primary cause of irreversible blindness in the U.S. There is substantial evidence that pathological mechanical stimulation mediated by an increase in intraocular pressure (IOP) plays a causal role in the etiology of glaucoma. The present proposal is to characterize the molecular mechanisms which might underlie the cellular response in this disease but could also play a key function in other diseases that involve mechanical stress in the retina, such as diabetic retinopathy, ischemia and macular edema. We found that a mechanosensitive cation channel, TRPV4, is selectively localized to retinal ganglion cells (RGCs) and in Muller glial cells. Because these are the two cell types that are specifically targeted in glaucoma, we hypothesize that mechanosensitive channels mediate the effects of pathological increases in IOP. The central focus of the proposal is to characterize this transduction mechanism in RGCs by combining biophysical, cellular and translational approaches. Studies proposed in Aim 1 will establish the molecular mechanism of mechanosensitive channel activation and desensitization, their role in calcium transport, cellular physiology and RGC survival. We will test conditions that mimic RGC injury in "low-tension" pathologies and test a number of models under which mechanosensitive channels might contribute to excitotoxic RGC injury. The proposed studies will also capitalize on preliminary work which shows remarkable effectiveness of non toxic small molecule antagonists in blocking pressure-stimulated loss of RGCs in vitro and in vivo glaucoma models. Aim 2 of the proposed research builds on the characterization of pressure-sensitive channels in Aim 1 to study how these mechanisms regulate the swelling response of RGCs and retinal astroglia. Although cells typically swell in response to normal light-evoked neuronal activity, swelling is exacerbated in pathological conditions such as ischemia and diabetes, and can be highly neurotoxic. The proposed studies will explore the molecular complexes that involve swelling-activated calcium channels, water channels, calcium waves and regulatory volume decrease mechanisms. Thus, the goal of proposed research is to establish an intuitive conceptual and experimental framework that helps unify our understanding of retinal IOP transduction, cell swelling, and volume sensing and calcium homeostasis in retinal cells. By doing so, it will help predict the effects of mechanical forces that act through direct hydrostatic compression of cellular membranes as well as determine molecular mechanisms that are activated by tensile stretching, pulling and swelling. We will then test these predictions using mouse models of inducible and chronic glaucoma. This may help to refine our understanding of mechanical injury in vision disorders such as glaucoma, diabetic retinopathy and ischemia and contribute to developing effective neuroprotective treatments.

描述（由申请人提供）：青光眼具有毁灭性盲目疾病的复杂性，这些疾病代表了美国不可逆性失明的主要原因，有大量证据表明，病理学机械刺激是由眼内压（IOP）增加在glaucoma的病因学中起着因果关系的作用。目前的建议是表征可能是该疾病中细胞反应的分子机制，但也可以在涉及视网膜机械应力的其他疾病中起关键功能，例如糖尿病性视网膜病变，缺血和黄斑水肿。我们发现机械敏感的阳离子通道TRPV4被选择性地定位于视网膜神经节细胞（RGC）和Muller Glial细胞中。因为这些是特异性针对青光眼中的两种细胞类型，所以我们假设机械敏感的通道介导了IOP中病理增加的影响。该提案的主要重点是通过结合生物物理，细胞和翻译方法来表征RGC中这种转导机制。在AIM 1中提出的研究将建立机械敏感通道激活和脱敏的分子机制，它们在钙转运，细胞生理和RGC存活中的作用。我们将测试条件，以模仿“低张力”病理中的RGC损伤，并测试许多模型，在这些模型下，机械敏感的通道可能导致兴奋性RGC损伤。拟议的研究还将利用初步工作，该工作表明，非毒性小分子拮抗剂在阻断体外和体内青光眼模型的压力刺激损失方面的出色效率。拟议的研究的目标2建立在AIM 1中压力敏感通道的表征，以研究这些机制如何调节RGC和视网膜星形胶质细胞的肿胀反应。尽管细胞通常会响应正常的光诱发神经元活性而肿胀，但在缺血和糖尿病等病理状况下肿胀会加剧，并且可以高度神经毒性。拟议的研究将探索涉及肿胀激活的钙通道，水通道，钙波和调节体积减少机制的分子复合物。因此，拟议的研究的目的是建立一个直观的概念和实验框架，有助于统一您对视网膜细胞中视网膜IOP转导，细胞肿胀以及体积感应和钙稳态的理解。通过这样做，它将有助于预测通过直接的细胞膜静水压压缩起作用的机械力的作用，并确定通过拉伸，拉伸和肿胀激活的分子机制。然后，我们将使用诱导和慢性青光眼的小鼠模型测试这些预测。这可能有助于完善我们对视力障碍的机械损伤的理解，例如青光眼，糖尿病性视网膜病和缺血，并有助于开发有效的神经保护疗法。