Pharmacology of Intravesical Antisense Based Therapy for Over Active Bladder

由于目前治疗膀胱过动症（OAB）或下尿路症状（LUTS）的方法有限，因此迫切需要开发新的治疗策略。在本应用中，以下主要目标利用William Beaumont医院和匹兹堡大学提供的独特和创新的专业知识，开发针对OAB和逼尿肌过度活动（DO）的新治疗方案，特别是针对膀胱传入高兴奋性，这被认为是OAB的重要机制之一，使用脊髓损伤（SCI）大鼠。序列特异性基因沉默机制是基于合理的基因药物设计开发治疗药物的一个有前途的途径。在目前的建议中，我们建议使用这种方法在膀胱局部沉默神经生长因子（NGF）基因。在膀胱中局部抑制NGF基因，类似于用于角膜血管生成的反义滴眼液，可以避免使用单克隆人NGF抗体（tanezumab）进行全身抗NGF治疗（如感觉异常、感觉减退和关节痛）所引起的安全性问题。通过比较不同途径给药的NGF反义的药理作用，我们拟探讨来自尿路上皮的NGF对脊髓损伤动物传入神经高兴奋性导致DO的作用。其次，我们还将验证电压门控钠和钾通道的改变、细胞因子表达/释放增加以及毒蕈碱受体的改变引发OAB病理的假设，这些变化是由膀胱中过量的NGF表达介导的。本实验将使用反义方法来阐明NGF抑制是否可以使毒碱和离子通道机制的变化正常化，从而导致DO/OAB的传入高兴奋性。我们将研究局部毒蕈碱胆碱能机制在DO中的变化，包括对各种抗毒蕈碱药物敏感性的改变。这一机制的研究非常重要，因为越来越多的证据表明，尿路上皮在拉伸过程中释放的非神经乙酰胆碱（ACh）可以激活毒蕈碱受体，导致排尿反射过程中传入通路的调节，并且膀胱中ACh水平的升高可以通过对尿路上皮/尿路上皮下毒蕈碱受体的局部作用诱导OAB。该研究项目的长期目标是为OAB的治疗建立新的有效的治疗靶点和/或干预策略。

DESCRIPTION: Because of current, limited options for treating overactive bladder (OAB) or lower urinary tract symptoms (LUTS), there is a great demand for the development of new treatment strategy. In this application, the following key aims utilize unique and innovative expertise, available at William Beaumont Hospital and University of Pittsburgh to develop new therapeutic options for OAB and detrusor overactivity (DO) by especially targeting bladder afferent hyperexcitability, which has been proposed as one of the important mechanisms underlying OAB, using rats with spinal cord injury (SCI). Sequence-specific gene-silencing mechanism is a promising approach for developing therapeutics agent based on rational gene-based drug design. In the current proposal, we propose to use this approach for silencing nerve growth factor (NGF) gene locally in the bladder. Local inhibition of NGF gene in bladder akin to antisense eye drops for corneal angiogenesis can avoid the safety concerns noted with systemic anti-NGF therapy from monoclonal human NGF antibodies (tanezumab) such as paresthesia, hypoesthesia and arthralgia. By comparing the pharmacology of NGF antisense administered via different routes, we propose to investigate the contribution of NGF derived from urothelium on afferent hyperexcitability leading to DO in SCI animals. Secondly, we will also test the hypothesis of OAB pathology triggered by changes in voltage- gated sodium and potassium channels, increased cytokines expression/release as well as muscarinic receptors, and such changes are mediated by excessive NGF expression in bladder. The proposed experiments will use antisense to elucidate whether NGF inhibition could normalize changes in muscarinic and ion channel mechanisms contributing to afferent hyperexcitability resulting in DO/OAB. We will study the changes in the local muscarinic cholinergic mechanism underlying DO, including altered sensitivity to various antimuscarinic agents. This mechanism is important to investigate because there is increasing evidence that non-neural acetylcholine (ACh) released from the urothelium during stretch can activate muscarinic receptors, leading to modulation of afferent pathways during the micturition reflex, and that increased ACh levels in the bladder can induce OAB mediated by the local effects on muscarinic receptors in the urothelium/suburothelium. The long-term objectives of the research program are to establish new and effective therapeutic targets and/or interventions strategies for the treatment of OAB.