RESCUE OF ALPORT SYNDROME OTOPATHOLOGY

阿尔波特综合征的拯救耳病理学

基本信息

批准号：
9214327
负责人：
Dominic E. Cosgrove
金额：
$ 47.44万
依托单位：
FATHER FLANAGAN'S BOYS' HOME
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-02-03 至 2021-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9214327
关键词：
Address Age Animals Basement membrane Binding Bioenergetics Biomechanics Blood capillaries CDC42 gene Cell Line Cells Cochlea Cochlear duct Collagen Computer software Deposition Disease Disease Progression Drops Drug Targeting Dysmorphology Ear Endothelial Cells Endothelin A Receptor Endothelin-1 Environment Event Extracellular Matrix Filopodia Focal Adhesion Kinase 1 Frequencies Functional disorder Gelatinase A Gene Expression Genes Glomerular Capillary Glomerular Mesangial Cell Hereditary nephritis Hypoxia Immunofluorescence Immunologic In Vitro Inflammatory Invaded Kidney Diseases Kidney Failure Kidney Glomerulus Labyrinth Laminin Lateral Life Longevity MAPK8 gene Matrix Metalloproteinases Measures Mediating Metabolic Metabolic stress Metabolism Metalloproteases Mitochondria Molecular Mus Na(+)-K(+)-Exchanging ATPase Nature Noise Noise-Induced Hearing Loss Oxides PTK2 gene Paper Pathogenesis Pathologic Pathology Pathway interactions Permeability Phenotype Physiological Predisposition Proteins Proteinuria RNA Receptor Signaling Reduced Glutathione Renal glomerular disease Reverse Transcriptase Polymerase Chain Reaction SLC2A1 gene Sensorineural Hearing Loss Series Signal Pathway Signal Transduction Stress Stretching Stria Vascularis Symptoms Testing Thick Time Transcript United States National Institutes of Health Vascular Endothelial Growth Factors Vascular Permeabilities Wild Type Mouse Work capillary cytokine gene induction glomerular basement membrane hearing impairment in vivo interstitial laminin alpha 2 laminin alpha1 laminin alpha5 mouse model podocyte prevent public health relevance rho GTP-Binding Proteins small molecule inhibitor

项目摘要

DESCRIPTION (provided by applicant): Alport syndrome is characterized by renal disease associated with sensorineural hearing loss. While much is known about the molecular nature of Alport glomerular and interstitial kidney disease, the mechanisms underlying the hearing loss phenotype remain relatively underexplored. In a series of recent papers and some unpublished results, we have revealed a mechanism for glomerular disease initiation involving activation of endothelin-1 that activates the formation of mesangial filopodia through the endothelin A receptor (ETAR). The filopodia invade the capillaries progressively leaving punctate deposits of mesangial matrix proteins, including laminin 211, in the glomerular basement membrane (GBM). The laminin 211 activates focal adhesion kinase on podocytes, leading to maladaptive gene expression that drives glomerular pathogenesis. Inhibiting this pathway by blocking ETAR has a profound effect on glomerular disease progression in the mouse model. As in the GBM, the strial capillary basement membranes (SCBMs) gradually thicken in Alport mice. These events result in a hypoxic environment in the scala media and a sensitivity to noise-induced hearing loss with a significant drop in the endocochlear potential (EP), proving that in the mouse, hearing loss is due to strial dysfunction. We show preliminary evidence that endothelin-1, laminin 211, collagen α1(IV), and laminin α5 are up-regulated in the stria vascularis of Alport mice relative to wild type mice, and are associated with FAK activation. Endothelin A receptors (ETARs) are present on strial marginal cells, and ETAR blockade prevents SCBM thickening and accumulation of matrix in the SCBM. Our central hypothesis is: Treatment of Alport mice with the ETAR antagonist Sitaxentan will prevent SCBM thickening and normalize strial function, preventing hearing loss and protecting animals from the inner ear metabolic stresses and pathology normally associated with Alport syndrome in the mouse model. We will address this in four specific aims: In the first we will determine whether ETAR blockade in the mouse model normalizes expression of ECM proteins and MMPs, SCBM thickness and permeability. In the second aim we will utilize a strial marginal cell line to probe the mechanism of ET-1 induction and ETAR signaling as it relates to induction of genes encoding ECM and MMPs. In the third we will determine whether normalization of SCBM thickness via ETAR blockade results in normalization of endocochlear potentials (EPs) and protection from noise induced hearing loss. Lastly, we will determine whether we have achieved metabolic rescue and return of normoxia by measuring noise induced mitochondrial ROS, oxidized/reduced glutathione ratios, and ATP levels in the stria of Alport mice compared to Alport mice under ETAR blockade. The discovery of this pathway suggests that a single drug target, in this case small molecule inhibitors that block ETAR, may provide a means of ameliorating both the glomerular and inner ear pathologies associated with Alport syndrome.

描述（由申请人提供）：Alport 综合征的特征是与感音神经性听力损失相关的肾脏疾病，尽管人们对 Alport 肾小球和间质性肾病的分子性质了解很多，但听力损失表型背后的机制仍相对未得到充分研究。根据最近的论文和一些未发表的结果，我们揭示了一种肾小球疾病发生的机制，涉及内皮素-1的激活，内皮素-1通过内皮素A激活系膜丝状伪足的形成丝状伪足逐渐侵入毛细血管，在肾小球基底膜 (GBM) 中留下包括层粘连蛋白 211 在内的点状沉积。层粘连蛋白 211 激活足细胞上的粘着斑激酶，导致驱动肾小球的适应不良基因表达。通过阻断 ETAR 来抑制该通路对小鼠模型中的肾小球疾病进展具有深远的影响。在 GBM 中，Alport 小鼠的心房毛细血管基底膜 (SCBM) 逐渐增厚，这些事件导致阶介质中的缺氧环境和对噪声引起的听力损失的敏感性，并导致耳蜗内电位 (EP) 显着下降。证明小鼠听力损失是由于纹状体功能障碍引起的我们初步证据表明内皮素-1、层粘连蛋白 211、胶原蛋白 α1(IV) 和层粘连蛋白 α5 是由纹状体功能障碍引起的。相对于野生型小鼠，Alport 小鼠的血管纹中的表达上调，并且与纹状体边缘细胞上存在的内皮素 A 受体 (ETAR) 激活相关，并且 ETAR 阻断可防止 SCBM 增厚和 SCBM 中基质的积累。我们的中心假设是：用 ETAR 拮抗剂 Sitaxentan 治疗 Alport 小鼠将防止 SCBM 增厚并使纹状体功能正常化，预防听力损失并保护动物免受内耳代谢应激和病理的影响通常与小鼠模型中的 Alport 综合征相关，我们将通过四个具体目标来解决这个问题：第一个目标是确定小鼠模型中的 ETAR 阻断是否使 ECM 蛋白和 MMP 的表达、SCBM 厚度和渗透性正常化。将利用心房边缘细胞系来探究 ET-1 诱导和 ETAR 信号传导的机制，因为它与编码 ECM 和 MMP 的基因的诱导有关。在第三部分中，我们将确定是否通过 ETAR 使 SCBM 厚度正常化。阻断导致耳蜗电位 (EP) 正常化并防止噪音引起的听力损失。最后，我们将通过测量噪音诱导的线粒体 ROS、氧化/还原型谷胱甘肽比率和 ATP 水平来确定我们是否已实现代谢救援和恢复正常氧氧。 Alport 小鼠的纹状体与 ETAR 阻断下的 Alport 小鼠相比。这一途径的发现表明，单一药物靶标（在本例中为阻断 ETAR 的小分子抑制剂）可能是有效的。提供了一种改善与阿尔波特综合征相关的肾小球和内耳病理的方法。