Cystitis-Induced Plasticity of Micturitin Reflexes

描述（由申请人提供）：膀胱疼痛综合征（BPS）/间质性膀胱炎（IC）是一种慢性疼痛综合征，其特征为感觉到与至少一种泌尿系统症状相关的膀胱疼痛、压迫或不适。BPS/IC对生活质量和经济负担的影响是巨大的。在本研究期间，我们假设与BPS/IC相关的疼痛涉及内脏感觉/膀胱感觉生理学的改变。内脏感觉的变化可以部分地由膀胱中的炎性变化（包括神经生长因子（NGF））介导。在BPS/IC患者中特异性抑制NGF的单克隆抗体治疗证明了概念的证据;然而，由于严重的副作用，临床试验已经停止招募。显然，需要在NGF之外的其他靶点。通过这种竞争性的更新申请，我们提出的目标是，将提供机制洞察到其他的神经生长因子介导的多效性的变化，有助于膀胱反射亢进和盆腔超敏反应在一种新的转基因小鼠模型的慢性神经生长因子过表达（NGF-OE）使用尿路上皮特异性uroplakin II启动子，其特征在于在最后一个资金周期。工作假设是，伴随BPS/IC的排尿频率增加和感觉改变是由于膀胱反射感觉肢中神经化学介质和感觉换能器，瞬时受体电位（TRPV）家族成员TRPV 4的表达，功能和相互作用的改变。这些研究检查了神经肽PACAP和受体PAC 1和TRPV 4对NGF-OE小鼠排尿频率和躯体敏感性增加的贡献和相互作用。目标1：我们假设，在NGF-OE小鼠模型的尿道和腰骶背根神经节（DRG）中展示的NGF过表达诱导DRG中的膀胱传入细胞和膀胱的尿路上皮细胞中的感觉换能器TRPV 4的上调。我们推测，TRPV 4的组织特异性表达，在排尿反射的感觉组件（尿道，DRG）有助于膀胱反射亢进和盆腔神经生长因子-OE小鼠的超敏反应。目标二：我们假设TRPV 4和PACAP/PAC 1之间的相互作用可能代表了一种新的机制，通过这种机制，PACAP/PAC 1信号激活磷脂酶C和三磷酸肌醇，使TRPV 4介导的排尿行为和疼痛感觉的变化敏感。此外，我们假设PAC 1和TRPV 4在膀胱传入DRG和尿路上皮细胞中共表达。我们将使用多学科的方法，包括解剖学，生物化学，分子，电生理学和功能的方法和一种新的离体外周神经记录方法来解决这些目标。研究结果将为具有治疗潜力的新靶点提供关键见解，以改善膀胱功能和内脏感觉。

DESCRIPTION (provided by applicant): Bladder pain syndrome (BPS)/interstitial cystitis (IC) is a chronic pain syndrome characterized by pain, pressure or discomfort perceived to be bladder related with at least one urinary symptom. The impact of BPS/IC on quality of life and economic burden are enormous. Over the life of this grant, we have hypothesized that pain associated with BPS/IC involves an alteration of visceral sensation/bladder sensory physiology. Changes in visceral sensation may be mediated, in part, by inflammatory changes in the urinary bladder including nerve growth factor (NGF). Monoclonal antibody treatment that specifically inhibits NGF in patients with BPS/IC demonstrates proof of concept; however, clinical trials have halted enrollment due to severe side effects. The need for additional targets beyond NGF is clear. With this competitive renewal application, we propose aims that will provide mechanistic insight into additional NGF-mediated pleiotropic changes that contribute to urinary bladder hyperreflexia and pelvic hypersensitivity in a novel transgenic mouse model of chronic NGF overexpression (NGF-OE) using the urothelium-specific uroplakin II promoter that was characterized during the last funding cycle. The working hypothesis is that increases in urinary frequency and altered sensation that accompany BPS/IC are due to an alteration in the expression, function and interactions of neurochemical mediators and the sensory transducer, transient receptor potential (TRPV) family member TRPV4, in the sensory limb of the urinary bladder reflex. These studies examine the contributions of and interactions between the neuropeptide, PACAP, and receptor PAC1 and TRPV4 to increased voiding frequency and somatic sensitivity in NGF-OE mice. Aim 1: We hypothesize that NGF overexpression exhibited in urothelium and lumbosacral dorsal root ganglia (DRG) of the NGF-OE mouse model induces upregulation of the sensory transducer, TRPV4, in bladder afferent cells in DRG and in urothelial cells of the urinary bladder. We hypothesize that tissue-specific expression of TRPV4, in sensory components (urothelium, DRG) of the micturition reflex contributes to urinary bladder hyperreflexia and pelvic hypersensitivity in NGF-OE mice. Aim 2: We hypothesize that interactions between TRPV4 and PACAP/PAC1 may represent a novel mechanism by which PACAP/PAC1 signaling activates phospholipase C and inositol triphosphate to sensitize TRPV4-mediated changes in voiding behavior and painful sensation. Furthermore, we hypothesize that PAC1 and TRPV4 are co-expressed in bladder afferent DRG and urothelial cells. We will use a multidisciplinary approach including anatomical, biochemical, molecular, electrophysiological, and functional methodologies and a novel ex vivo peripheral nerve recording approach to address these aims. Results will provide key insights into new targets with therapeutic potential to improve urinary bladder function and visceral sensation.