Role of NGF signaling in the bladder after spinal cord injury

NGF信号在脊髓损伤后膀胱中的作用

基本信息

批准号：
9095711
负责人：
Anthony John Kanai
金额：
$ 11.55万
依托单位：
OHIO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-09-03 至 2016-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9095711
关键词：
Address Apoptosis Apoptotic Ataxia Attenuated Basal Cell Binding Biological Assay Biological Markers Biology Bladder Bladder Control Bladder Dysfunction Cells Cerebrospinal Fluid Cessation of life Chronic Complement Cystitis Data Development Erinaceidae FDA approved Fiber Functional disorder Genetic Health Hyperplasia Hyperreflexia Hypertrophy In Situ Nick-End Labeling Injury Interstitial Cystitis Knockout Mice Maps Measurement Mediating Motor Mus NGFR Protein Natural regeneration Neuronal Plasticity Neurotrophic Tyrosine Kinase Receptor Type 1 Optics Oral Outcome Study Overactive Bladder Pain Permeability Pharmaceutical Preparations Play Proliferating Publishing Recombinants Role Signal Transduction Sphincter Spinal Spinal Anesthesia Spinal cord injury Stem cells System Testing Time Toxic effect Urethral sphincter Urine Urothelial Hyperplasia Urothelium afferent nerve base design improved in vitro Assay in vivo inhibitor/antagonist injured interest motor function improvement neurotrophic factor novel progenitor receptor response restoration small molecule therapeutic target transcriptional coactivator p75 urologic

项目摘要

DESCRIPTION (provided by applicant): We have recently published that a NGF receptor, p75, is a potential therapeutic target for the spinal cord injured: motor function after spinal cor injury (SCI) improved after oral delivery of LM11A-31, a small molecule that was designed to target p75. Effective in vivo targeting of p75 by LM11A-31 was confirmed by observation of a block in binding of a pathological proNGF to p75, suggesting that the drug can be used in other systems where p75 exerts similar pathological effects upon interaction with proNGF or other proneurotrophins. We have published that ProNGF levels increase rapidly after injury to the CNS, being released into the cerebrospinal fluid. Unlike mature NGF that binds both TrkA and p75, proNGF binds p75 selectively, thereby activating p75's downstream apoptotic cascade. NGF has been implicated in bladder dysfunction after SCI as well as in overactive bladder and interstitial cystitis/painful bladder syndromes. Under these conditions and after SCI, a significan increase in NGF levels is observed in the urine, suggesting that NGF can be a biomarker for general bladder dysfunction and may be targeted to improve bladder function. Despite the long-standing interest, however, studies that aimed at neutralizing NGF action has led to mixed results. We believe a more detailed understanding of the roles that NGF and its receptors play in bladder biology will be necessary before we focus on NGF and related neurotrophins as therapeutic target for alleviating bladder dysfunction. We have found that proNGF and proBDNF are released into the urine shortly after SCI, while mature NGF is released days later. These proneurotrophins appear to induce apoptosis of umbrella cells that are responsible for establishing the permeability barrier, as LM11A-31 administration led to retention of umbrella cells after SCI. We thus hypothesize that p75 that is expressed in umbrella cells play a role in apoptosis of umbrella cells after SCI. In addition to umbrella cells, we found that p75 is also expressed in proliferating progenitors of the urothelium during the period of urothelial hyperplasia after SCI. LM11A-31 administration attenuated this hyperplasic response, suggesting that proneurotrophins and p75 play an additional role in regulating SCI-induced hyperplasia. We thus hypothesize that p75 plays dual roles in the regeneration of the urothelium after SCI, (1) by inducing apoptosis of the umbrella cells shortly after SCI, and (2) by regulating proliferation of the progenitor cells, thereby replenishing the lost umbrella cells. Under this hypothesis, we propose to determine whether p75 induces death of umbrella cells in the urothelium after SCI (Aim 1), which will be addressed by conditional p75 mice, in which p75 is selectively deleted in umbrella cells; to determine the role of p75 in proliferation of the urothelium after SCI (Aim 2), which will be addressed by analyzing mice after SCI in which p75 is deleted in urothelial progenitors; and to determine whether LM11A-31 improves bladder function after SCI (Aim 3), which will be addressed using novel optical mapping approaches, single-unit afferent nerve recording, permeability measurements and cystometrograms (CMG) with simultaneous urethral sphincter electromyograms (EMG). We believe the outcome of this study will change our current understanding on neurotrophin action in the bladder and energize the existing effort to target neurotrophin in improving bladder function in various urological conditions.

描述（由申请人提供）：我们最近发表了 NGF 受体 p75 是脊髓损伤的潜在治疗靶点：口服小分子 LM11A-31 后脊髓损伤（SCI）后的运动功能得到改善通过观察病理性 proNGF 与 p75 的结合的阻断证实了 LM11A-31 能够有效体内靶向 p75，这表明该药物可以与结合 TrkA 和 p75 的成熟 NGF 不同，p75 在与 proNGF 或其他前神经营养素相互作用后发挥类似病理作用的其他系统中，ProNGF 水平在中枢神经系统损伤后迅速增加。 proNGF 选择性地结合 p75，从而激活 p75 的下游凋亡级联反应，NGF 与 SCI 后的膀胱功能障碍有关。在膀胱过度活动症和间质性膀胱炎/膀胱疼痛综合征中，在这些条件下以及 SCI 后，可以观察到尿液中 NGF 水平显着增加，这表明 NGF 可以作为一般膀胱功能障碍的生物标志物，并且可以作为改善膀胱功能的目标。然而，尽管人们长期以来对 NGF 作用感兴趣，但旨在中和 NGF 作用的研究却得出了不同的结果，我们认为，在我们关注 NGF 及其相关药物之前，有必要更详细地了解 NGF 及其受体在膀胱生物学中的作用。我们发现，在 SCI 后不久，proNGF 和 proBDNF 就会释放到尿液中，而成熟的 NGF 会在几天后释放，这些原神经营养素似乎会诱导负责建立通透性屏障的伞细胞凋亡。由于 LM11A-31 给药导致 SCI 后伞细胞保留，因此我们研究了伞细胞中表达的 p75 在 SCI 后伞细胞凋亡中发挥的作用。发现在 SCI 后尿路上皮增生期间，p75 也在尿路上皮增殖祖细胞中表达，从而减弱了这种增生反应，这表明前神经营养蛋白和 p75 在调节 SCI 诱导的增生中发挥着额外的作用。 p75 在 SCI 后尿路上皮的再生中发挥双重作用，（1）通过诱导伞细胞凋亡SCI 后不久的细胞，以及 (2) 通过调节在此假设下，我们建议确定 p75 是否会诱导 SCI 后尿路上皮中的伞细胞死亡（目标 1），这将通过条件性 p75 小鼠来解决，其中 p75在伞细胞中被选择性删除；以确定 p75 在 SCI 后尿路上皮增殖中的作用（目标 2），这将通过分析 SCI 后的小鼠来解决p75 在尿路上皮祖细胞中被删除；并确定 LM11A-31 是否可以改善 SCI 后的膀胱功能（目标 3），这将使用新型光学标测方法、单单位传入神经记录、渗透性测量和膀胱测压图 (CMG) 来解决我们相信这项研究的结果将改变我们目前对膀胱和神经营养蛋白作用的理解。为现有的针对神经营养素改善各种泌尿系统疾病膀胱功能的努力注入活力。