Pharmacology of Intravesical Antisense Based Therapy for Over Active Bladder

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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.