Cystitis-Induced Plasticity of Micturitin Reflexes

描述(申请人提供)：膀胱痛综合征(BPS)/间质性膀胱炎(IC)是一种慢性疼痛综合征，其特征是疼痛、压迫或不适被认为与至少一种泌尿系统症状有关。BPS/IC对生活质量和经济负担的影响是巨大的。在这项资助的整个过程中，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。内脏感觉的变化可能部分是通过膀胱炎性变化来调节的，包括神经生长因子(NGF)。在BPS/IC患者中特异性抑制NGF的单抗治疗证明了概念的正确性；然而，由于严重的副作用，临床试验已经停止了招募。很明显，除了NGF之外，还需要更多的目标。通过这一竞争性更新应用，我们提出的AIMS将提供对其他NGF介导的多效性变化的机械性洞察，这些变化有助于慢性NGF过度表达转基因小鼠(NGF-OE)中的膀胱反射亢进和盆腔超敏反应(NGF-OE)，该模型使用上一个资助周期中表征的尿路上皮特异性Uroplakin II启动子。工作假说是，伴随BPS/IC的尿频增加和感觉改变是由于神经化学介质和膀胱反射感觉肢上的感觉转导--瞬时受体电位(TRPV)家族成员TRPV4的表达、功能和相互作用的改变。这些研究检验了神经肽、PACAP以及受体PAC1和TRPV4在增加NGF-OE小鼠的排尿频率和躯体敏感性方面的贡献和相互作用。目的：我们推测NGF-OE模型小鼠的尿路上皮和腰骶背根神经节(DRG)中NGF的过度表达导致DRG中的膀胱传入细胞和膀胱的尿路上皮细胞中感觉转导分子TRPV4的表达上调。我们假设，TRPV4在排尿反射的感觉成分(尿路上皮，DRG)中的组织特异性表达与NGF-OE小鼠的膀胱反射亢进和盆腔过敏有关。目的：我们推测，TRPV4与PACAP/PAC1之间的相互作用可能代表了一种新的机制，即PACAP/PAC1信号激活磷脂酶C和三磷酸肌醇，从而敏化TRPV4介导的排尿行为和痛觉变化。此外，我们假设PAC1和TRPV4在膀胱传入背根节和尿路上皮细胞中共表达。我们将使用包括解剖学、生化、分子、电生理和功能方法在内的多学科方法和一种新的体外周围神经记录方法来解决这些目标。研究结果将为具有改善膀胱功能和内脏感觉的治疗潜力的新靶点提供关键见解。

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.