Cystitis-Induced Plasticity of Micturition Reflexes

描述(申请人提供)：痛性膀胱综合症(PBS)/间质性膀胱炎(IC)是一种慢性症状复合体，以尿频、尿急、耻骨上、盆腔疼痛和膀胱镜检查为特征。这项研究的假设是，伴随PBS/IC的排尿频率和感觉改变的增加是由于排尿反射的初级传入肢体的改变，部分原因是脊髓神经元间机制的改变。膀胱炎患者尿频增加也可能是由于排尿反射的传出肢体改变所致。这些变化的组合通过改变神经元间水平和骨盆神经节的突触传递，促进了脊髓反射途径到膀胱的作用。神经生长因子(NGF)和NGF/受体酪氨酸激酶(TrkA)的相互作用在炎症诱导的膀胱功能改变、下尿路(LUT)通路的神经化学可塑性和LUT反射的中枢组织中的作用已被明确。建议的目的是通过使用CYP大鼠膀胱炎模型、一个新的慢性过表达NGF小鼠系(UPII-NGFv2)和多学科实验方法，从机制上深入了解炎症诱导的排尿反射神经控制的变化。目的：模拟慢性膀胱炎和PBS/IC的环境，以尿路上皮神经生长因子(UPII-NGFv2)慢性高表达小鼠为模型，采用有意识膀胱测压、免疫组织化学和细胞内记录技术，研究NGF在调节膀胱反射功能、神经化学和组织可塑性中的作用。神经可塑性是否继发于排尿反射的神经化学表型的改变将被确定。目的：p75NTR和Trk受体相互作用调节TrkA受体与其同源配体NGF的亲和力。Trk和p75NTR介导的信号在LUT通路中的作用将被确定为对照组、CYP治疗的啮齿动物、UPII-NGFv2和回交野生型小鼠。这些研究将使用药理学工具来阻断NGF/TrkA和NGF/p75信号。目的3：神经营养素诱导信号的生物学作用尚不清楚，尤其是在LUT中。测定大鼠和UPII-NGFv2小鼠在CYP诱导的膀胱炎后腰骶髓、背根神经节和膀胱中ERK1/2、ERK5和Akt的瞬时激活情况。应用ERK或PI3K抑制剂后，将确定脊髓排尿反射的神经化学性质和组织结构。这些研究可能为未来PBS/IC的潜在靶点和治疗干预提供见解。 公共卫生相关性 痛性膀胱综合征(PBS)/间质性膀胱炎(IC)是一种以尿频、尿急、耻骨上、盆腔疼痛和膀胱镜检查为特征的慢性症状复合体。炎症诱导的生长因子(如神经生长因子，NGF)在PBS/IC患者的膀胱或尿液中的表达，以及随后与中枢和周围神经系统的相互作用可能导致这些症状。这些研究将确定NGF与膜结合受体的相互作用和细胞信号事件的激活如何促进膀胱功能障碍和感觉处理的变化。这些研究将有助于了解炎症诱导的慢性膀胱炎的变化，并可能为未来PBS/IC的潜在靶点和治疗干预提供见解。

DESCRIPTION (provided by applicant): Painful Bladder Syndrome (PBS)/Interstitial Cystitis (IC) is a chronic symptom-complex characterized by urinary frequency, urgency, suprapubic, pelvic pain and cystoscopic findings. The hypothesis for this research proposal is that increases in voiding frequency and altered sensation that accompany PBS/IC are due to an alteration in the primary afferent limb of the micturition reflex and, in part, to an alteration in interneuronal mechanisms in the spinal cord. Increased urinary frequency with cystitis may also be due to an alteration in the efferent limb of the micturition reflex. The combination of these changes facilitates a spinal reflex pathway to the urinary bladder by altering synaptic transmission at the interneuronal level and to the pelvic ganglia. The contribution of nerve growth factor (NGF) and NGF/receptor tyrosine kinase (TrkA) interactions to inflammatory-induced changes in urinary bladder function, neurochemical plasticity in lower urinary tract (LUT) pathways and central organization of LUT reflexes has been defined. The proposed aims provide mechanistic insight into inflammation-induced changes in neural control of micturition reflexes using the CYP rat model of urinary bladder inflammation, a novel, chronic overexpressing NGF mouse line (UPII-NGFv2) and a multidisciplinary experimental approach. Aim 1: To mimic the environment of chronic bladder inflammation and PBS/IC, mice with chronic overexpression of NGF in the urothelium (UPII-NGFv2) will be used to determine the role that NGF plays in mediating functional, neurochemical and organizational plasticity of bladder reflexes using conscious cystometry, immunohistochemistry and intracellular recording techniques. Whether neural plasticity is secondary to changes in neurochemical phenotype of the micturition reflex will be determined. Aim 2: p75NTR and Trk receptors interact to regulate the affinity of TrkA receptor for its cognate ligand, NGF. The involvement of Trk versus p75NTR mediated signaling in LUT pathways in control, CYP-treated rodents, UPII-NGFv2 and backcrossed wildtype mice will be determined. These studies will use pharmacological tools to block NGF/TrkA versus NGF/p75 signaling. Aim 3: The biological roles of neurotrophin-induced signals are unknown especially in the LUT. The temporal activation of ERK1/2, ERK5 and Akt in lumbosacral spinal cord, DRG and urinary bladder after CYP-induced cystitis in rats and in UPII-NGFv2 mice will be determined. The neurochemical properties and the organization of spinal micturition reflexes after administration of ERK or PI3K inhibitors will be determined. These studies may provide insights into potential targets and therapeutic interventions for PBS/IC in the future. PUBLIC HEALTH RELEVANCE Painful Bladder Syndrome (PBS)/Interstitial Cystitis (IC) is a chronic symptom-complex characterized by urinary frequency, urgency, suprapubic, pelvic pain and cystoscopic findings. Inflammation-induced expression of growth factors (e.g. nerve growth factor, NGF) in the urinary bladder or urine of women with PBS/IC and subsequent interactions with the central and peripheral nervous system may contribute to these symptoms. These studies will determine how NGF interactions with membrane bound receptors and activation of cellular signaling events could contribute to urinary bladder dysfunction and changes in sensory processing. These studies will contribute to the understanding of inflammation-induced changes in chronic bladder inflammation and may provide insights into potential targets and therapeutic interventions for PBS/IC in the future.