The neuropilin 2 axis in smooth muscle contractility

平滑肌收缩力中的神经毡蛋白 2 轴

基本信息

批准号：
9127579
负责人：
Rosalyn M Adam
金额：
$ 53.59万
依托单位：
BOSTON CHILDREN'S HOSPITAL
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：
2016-06-13 至 2021-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9127579
关键词：
Ablation Adverse effects Aging Agonist Agreement Biochemical Bladder Bladder Control Cholinesterase Inhibitors Chronic Clinical Clinical Management Clinical Treatment Complex Data Diabetes Mellitus Disease Etiology Evaluation Financial cost Functional disorder Gene Deletion Genetic Genetically Engineered Mouse Goals Healthcare Human Impairment In Vitro Incontinence Integral Membrane Protein Investigation Knock-out Lead Ligands Lower urinary tract Mediating Medical Mental Depression Modeling Mus Muscarinic Acetylcholine Receptor Muscarinics Muscle Muscle Contraction Muscle relaxation phase Myosin Light Chains Neuropilin-2 Neurotransmitters Obstruction Organ Parasympathomimetic Agents Pathway interactions Patients Pharmacotherapy Phenotype Phosphorylation Physiological Physiology Productivity Publishing Randomized Controlled Trials Recurrence Regulation Relaxation Rho-associated kinase Role Secondary to Semaphorins Signal Transduction Site Smooth Muscle Smooth Muscle Myocytes Social isolation Specimen Symptoms Testing Therapeutic Tissues Urinary Retention Urinary tract infection base body system cost in vivo lower urinary tract symptoms mouse model neuromuscular novel public health relevance social systematic review urolithiasis urologic

项目摘要

DESCRIPTION (provided by applicant): Bladder function depends on cycles of smooth muscle (SM) contraction and relaxation to achieve voiding and storage, respectively. Impairment of the strength or duration of bladder SM contraction characterizes a prevalent but poorly understood clinical condition termed detrusor underactivity (DU). DU is a complex disorder that (i) arises from diverse neuromuscular insults, including chronic bladder outlet obstruction, aging and persistent diabetes; (ii) reduces voiding efficiency and (iii) can lead to significant urologic complications. Irrespective of etiology, the loss of normal bladder contractilty in DU is a serious clinical problem that is not understood in mechanistic terms. Pharmacotherapy for DU is limited, comprising primarily parasympathomimetic agents, which have questionable efficacy and adverse side effects. More effective and tolerable treatment options to restore bladder contractility would represent a major therapeutic advance for patients suffering from DU. However, the goal of successful pharmacologic treatment of DU will only be realized by understanding mechanisms regulating bladder SM contraction and their dysregulation in DU. We recently identified the detrusor smooth muscle as a major site of expression of neuropilin 2 (Nrp2). Exposure of bladder smooth muscle cells to the neuropilin 2 ligand semaphorin 3F (SEMA3F) evoked profound cytoskeletal changes, accompanied by inhibition of RhoA, decreased myosin light chain phosphorylation, and reduced cytoskeletal stiffness. Consistent with this, forced expression of SEMA3F via adenoviral transduction in vivo led to reduced bladder SM contractility. Conversely, knockout of either Nrp2 or Sema3F in vivo enhanced bladder SM contractility compared to non-deleted controls. New data show that in bladders undergoing decompensation following partial bladder outlet obstruction (pBOO), Nrp2 deletion restored SM contractility compared to non-deleted controls. Lastly, new analysis of human bladder specimens revealed an inverse correlation between detrusor contractility and NRP2 expression. Based on these observations, we hypothesize that the SEMA3F-neuropilin 2 network inhibits bladder SM contractility in vivo and that targeting this axis restores contractile function under conditions of DU. The hypothesis will be tested with the following Specific Aims: (1) Determine the mechanisms underlying Sema3F- Nrp2-mediated inhibition of bladder SM contractility. (2) Determine the functional consequences of targeting the Sema3F-Nrp2 axis in a model of pBOO. We will employ novel mouse models of Nrp2- and Sema3F- deficiency, tension testing in muscle strips, biochemical and histological analyses, cystometric evaluation and a physiologically relevant mouse model of bladder outlet obstruction to achieve our objectives. At the end of the project period we expect to have determined the mechanism(s) whereby the Sema3F-Nrp2 axis inhibits smooth muscle contractility, the consequences of Sema3F and Nrp2 perturbation for bladder pathophysiology and how the Sema3F-Nrp2 network may be exploited therapeutically to restore contractility in DU.

描述（由申请人提供）：膀胱功能取决于平滑肌（SM）收缩和松弛的周期来分别实现排尿和储存。膀胱 SM 收缩的强度或持续时间的受损是一种普遍但知之甚少的临床病症，称为逼尿肌活动不足。 (DU) 是一种复杂的疾病，(i) 由多种神经肌肉损伤引起，包括慢性膀胱出口梗阻、衰老和持续性糖尿病；(ii) 排尿效率低下；(iii) 可能导致严重的症状。无论病因如何，DU 中正常膀胱收缩力的丧失是一个严重的临床问题，其机制尚不明确，主要包括拟副交感神经药物，其疗效值得怀疑且副作用较大。恢复膀胱收缩力的可耐受治疗方案将代表 DU 患者的重大治疗进展。然而，成功药物治疗 DU 的目标只有通过了解膀胱调节机制才能实现。 DU 中 SM 收缩及其失调。我们最近发现逼尿肌平滑肌是神经毡蛋白 2 (Nrp2) 的主要表达部位。膀胱平滑肌细胞暴露于神经毡蛋白 2 配体信号蛋白 3F (SEMA3F) 会引起严重的细胞骨架变化。通过抑制 RhoA，减少肌球蛋白轻链磷酸化，并降低细胞骨架硬度，与此一致，SEMA3F 的强制表达。通过体内腺病毒转导导致膀胱 SM 收缩力降低，与未删除的对照相比，体内 Nrp2 或 Sema3F 的敲除增强了膀胱 SM 收缩力。与未删除的对照相比，Nrp2 删除恢复了 SM 收缩性。最后，对人类膀胱样本的新分析揭示了逼尿肌收缩性与 NRP2 表达之间的负相关性。通过观察，我们发现 SEMA3F-neuropilin 2 网络在体内抑制膀胱 SM 收缩性，并且靶向该轴可恢复收缩性该假设将通过以下具体目标进行检验：（1）确定 Sema3F-Nrp2 介导的膀胱 SM 收缩性抑制的机制（2）确定靶向 Sema3F-Nrp2 轴的功能后果。我们将采用 Nrp2 和 Sema3F 缺陷的新型小鼠模型、肌肉条张力测试、生化和组织学分析、囊肿、度量评估和生理相关性。膀胱出口阻塞的小鼠模型以实现我们的目标，我们希望确定 Sema3F-Nrp2 轴抑制平滑肌收缩力的机制、Sema3F 和 Nrp2 扰动对膀胱病理生理学的影响以及如何在治疗上利用 Sema3F-Nrp2 网络来恢复 DU 的收缩性。