Identification of Novel Drug Targets For Use in Preventing Deafness Caused by NF2

鉴定用于预防 NF2 引起的耳聋的新药物靶点

• 批准号: 7878605
• 负责人: CRISTINA Maria FERNANDEZ-VALLE
• 金额: $ 29.66万
• 依托单位: UNIVERSITY OF CENTRAL FLORIDA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7878605
• 关键词: Acoustic Nerve; Acoustic Neuroma; Actins; Adult; Apoptosis; Auditory Brain Stem Implants; Autocrine Communication; Axon; Basal lamina; Binding; Brain Stem; Cancer Biology; Cell Death; Cell Shape; Cell membrane; Cell physiology; Cell-Cell Adhesion; Cells; Cellular Morphology; Complete Hearing Loss; Complex; Cues; Cyclic AMP-Dependent Protein Kinases; Cytokinesis; Cytoskeleton; Defect; Development; Disease; Drug Delivery Systems; Effectiveness; Equilibrium; Excision; Facial paralysis; Genes; Goals; Growth; Hearing; Human; In Vitro; Individual; Integrins; Investigation; LIM Domain Kinase 1; Laminin; Life; Ligands; Link; Malignant Neoplasms; Measures; Membrane; Membrane Proteins; Mitotic spindle; Molecular; Monitor; Morphology; Mus; Mutate; Mutation; Nerve; Neuregulins; Neurilemmoma; Neurofibromatoses; Neurofibromatosis 2; Neurofibromin 2; Neurons; Operative Surgical Procedures; Orphan; Outcome; Pathogenesis; Pathway interactions; Patients; Peptides; Pharmaceutical Preparations; Pharmacological Treatment; Phenotype; Phosphorylation; Plasmids; Play; Positioning Attribute; Process; Proteins; Rattus; Reagent; Regulation; Reporting; Research Personnel; Risk; Role; Schwann Cells; Serine; Shapes; Signal Pathway; Signal Transduction; Signaling Protein; Site; Spinal Ganglia; Stream; Subfamily lentivirinae; Symptoms; Teenagers; Testing; Therapeutic; Tumor Suppressor Proteins; Virus; Work; bilateral acoustic schwannoma; bilateral vestibular Schwannoma; cell motility; cofilin; cofilin 2; deafness; density; effective therapy; experience; extracellular; genetic regulatory protein; hearing impairment; in vitro Model; irradiation; novel; novel therapeutics; p21 activated kinase; paxillin; polymerization; prevent; receptor; repaired; response; success; tumor; tumor growth

DESCRIPTION (provided by applicant): Neurofibromatosis type 2 (NF2) is a tumor disorder characterized by development of bilateral vestibular schwannomas also called acoustic neuromas. 98% of all NF2 patients experience partial to complete loss of hearing. Treatment for NF2 is balanced between monitoring tumor growth and the slow but progressive loss of hearing with surgical removal of larger tumors impinging on brainstem function and complete and permanent deafness. Cochlear and auditory brainstem implants have been used to partially restore hearing in a subset of patients with varying success. Therapeutics that slow or reverse tumor growth whilst maintaining hearing are currently lacking. This proposal tests the hypothesis that correcting the cytoskeletal defects in supernumerary schwannoma cells lacking function of the nf2 gene product, schwannomin/merlin, will allow these cells to interact with axons and receive cues promoting their differentiation and/or apoptosis. Identifying proteins that directly bind actin and regulate Schwann cell morphology is of the utmost importance. These proteins can serve as targets for drugs that will repair actin dynamics in schwannoma cells and restore axonal contact. Alternatively, drugs that modify actin regulatory proteins could promote cell death as a result of failed cytokinesis and mitotic spindle organization. One function of schwanomin/merlin is to inhibit Cdc42/Rac activation of p21 activated kinase (PAK). We will investigate LIM kinase (LIMK) and cofilin, terminal targets in a PAK signaling pathway. LIMK is a substrate for PAK, thus its activity is predicted to be high in schwannomas. Cofilin is a ubiquitously expressed actin-binding factor that depolymerizes f-actin and creates nucleation sites for new actin polymerization. Cofilin's function is inhibited by phosphorylation on serine-3 by LIMK. Our preliminary studies demonstrate that LIMK and cofilin modulate actin dynamics and function in Schwann cells. Moreover, our results suggest that LIMK and cofilin act down-stream of Schwannomin/merlin. We propose studies to: 1) identify the role of these proteins in controlling actin polymerization and cellular function in normal rat Schwann cells, 2) establish an in vitro model for NF2 using nf2ex2deleted mouse SCs to determine if inactivation of schwannomin/merlin leads to de-regulation of LIMK and cofilin activity and loss of SC function, and 3) determine if modulators of LIMK and cofilin restore the morphology and function of nf2ex2deleted SCs. These studies are initial steps in validating LIMK and/or cofilin as drug targets for development of an effective treatment for NF2 aimed at preserving hearing. The work in this proposal is relevant to the loss of hearing caused by Neurofibromatosis type 2. This disorder is characterized by development of bilateral acoustic schwannomas and loss of hearing in 98% of patients. As an outcome of this proposal, we hope to create a well characterized in vitro model for NF2 and advance a novel therapeutic direction, the actin modifying proteins LIMK and cofilin.

描述（由申请人提供）：2型神经纤维瘤病（NF 2）是一种肿瘤疾病，其特征为双侧前庭神经鞘瘤（也称为听神经瘤）的发展。所有NF 2患者中有98%经历部分至完全听力损失。NF 2的治疗在监测肿瘤生长和缓慢但进行性听力丧失之间进行平衡，手术切除影响脑干功能的较大肿瘤和完全永久性耳聋。耳蜗和听觉脑干植入物已被用于部分恢复患者的听力，并取得了不同的成功。目前缺乏减缓或逆转肿瘤生长同时保持听力的治疗方法。这项提议验证了这样一个假设，即纠正缺乏nf 2基因产物神经鞘蛋白/梅林功能的多余神经鞘瘤细胞的细胞骨架缺陷，将使这些细胞与轴突相互作用，并接受促进其分化和/或凋亡的线索。鉴定直接结合肌动蛋白和调节雪旺细胞形态的蛋白质是至关重要的。这些蛋白质可以作为药物的靶点，修复神经鞘瘤细胞中的肌动蛋白动力学并恢复轴突接触。或者，药物修改肌动蛋白调节蛋白可能会促进细胞死亡，作为失败的胞质分裂和有丝分裂纺锤体组织的结果。施瓦诺明/梅林蛋白的一个功能是抑制Cdc 42/Rac对p21激活激酶（PAK）的激活。我们将研究LIM激酶（LIMK）和cofilin，在PAK信号通路的终端目标。LIMK是PAK的底物，因此预测其活性在神经鞘瘤中较高。Cofilin是一种广泛表达的肌动蛋白结合因子，它解聚肌动蛋白并为新的肌动蛋白聚合创造成核位点。Cofilin的功能被LIMK对丝氨酸-3的磷酸化抑制。我们的初步研究表明，LIMK和cofilin调节肌动蛋白的动力学和功能的雪旺细胞。此外，我们的研究结果表明，LIMK和cofilin行为的下游Schwannomin/梅林。我们建议开展以下研究：1）鉴定这些蛋白在控制正常大鼠雪旺细胞中肌动蛋白聚合和细胞功能中的作用，2）使用nf 2 ex 2缺失的小鼠SC建立NF 2的体外模型以确定雪旺蛋白/merlin的失活是否导致LIMK和cofilin活性的失调和SC功能的丧失，和3）确定LIMK和cofilin的调节剂是否恢复nf 2 ex 2缺失的SC的形态和功能。这些研究是验证LIMK和/或cofilin作为开发旨在保护听力的NF 2有效治疗药物靶点的初步步骤。本提案中的工作与2型神经纤维瘤病引起的听力损失有关。这种疾病的特点是发展双侧听神经鞘瘤和听力损失的98%的患者。作为这一建议的结果，我们希望建立一个良好的表征NF 2的体外模型，并提出一个新的治疗方向，肌动蛋白修饰蛋白LIMK和cofilin。