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

• 批准号: 8437597
• 负责人: DAVID KRIZAJ
• 金额: $ 37.32万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 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/8437597
• 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' 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

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）：青光眼是一种复杂的破坏性致盲疾病，共同代表了美国不可逆性失明的主要原因。有大量证据表明，由眼内压（IOP）升高介导的病理性机械刺激在青光眼的病因学中起着因果作用。目前的建议是表征可能是这种疾病中细胞反应的基础的分子机制，但也可能在涉及视网膜机械应力的其他疾病中发挥关键作用，如糖尿病视网膜病变，缺血和黄斑水肿。我们发现，机械敏感阳离子通道，TRPV4，选择性地定位于视网膜神经节细胞（RGCs）和Muller神经胶质细胞。因为这两种细胞类型是青光眼中特异性靶向的，我们假设机械敏感性通道介导IOP病理性增加的作用。该提案的中心焦点是通过结合生物物理，细胞和翻译方法来表征RGC中的这种转导机制。目标1中提出的研究将建立机械敏感性通道激活和脱敏的分子机制，它们在钙转运、细胞生理学和RGC存活中的作用。我们将测试条件下，模仿RGC损伤的“低张力”的病理和测试的一些模型下，机械敏感通道可能有助于兴奋毒性RGC损伤。拟议的研究还将利用初步工作，这些工作表明无毒小分子拮抗剂在体外和体内青光眼模型中阻断压力刺激的RGC损失方面具有显着的效果。目标2的研究建立在目标1中的压力敏感通道的特征上，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。尽管细胞通常响应于正常的光诱发的神经元活动而肿胀，但在病理条件下，如缺血和糖尿病，肿胀会加剧，并且可能具有高度神经毒性。这些研究将探索涉及膨胀激活的钙通道、水通道、钙波和调节性容积减少机制的分子复合物。因此，提出的研究的目标是建立一个直观的概念和实验框架，有助于统一我们的视网膜IOP转导，细胞肿胀，体积传感和视网膜细胞钙稳态的理解。通过这样做，它将有助于预测通过细胞膜的直接流体静力学压缩作用的机械力的影响，以及确定通过拉伸拉伸，拉动和溶胀激活的分子机制。然后，我们将使用诱导型和慢性青光眼的小鼠模型来测试这些预测。这可能有助于完善我们对视力障碍（如青光眼、糖尿病视网膜病变和缺血）中机械损伤的理解，并有助于开发有效的神经保护治疗。