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.
Bladder pain syndrome (BPS)/interstitial cystitis (IC) is a chronic pain syndrome with at least one urinary symptom. The impact of BPS/IC on quality of life and the resulting economic burden are enormous. The working hypothesis for this research proposal 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, TRPV4, in the sensory limb of the urinary bladder reflex. The results of these experiments will provide key, new insights into novel targets with therapeutic potential.
|Girard, Beatrice; Peterson, Abbey; Malley, Susan et al. (2016) Accelerated onset of the vesicovesical reflex in postnatal NGF-OE mice and the role of neuropeptides. Exp Neurol 285:110-125|
|Merrill, Liana; Gonzalez, Eric J; Girard, Beatrice M et al. (2016) Receptors, channels, and signalling in the urothelial sensory system in the bladder. Nat Rev Urol 13:193-204|
|Girard, Beatrice M; Malley, Susan; May, Victor et al. (2016) Effects of CYP-Induced Cystitis on Growth Factors and Associated Receptor Expression in Micturition Pathways in Mice with Chronic Overexpression of NGF in Urothelium. J Mol Neurosci 59:531-43|
|Gonzalez, Eric J; Peterson, Abbey; Malley, Susan et al. (2015) The effects of tempol on cyclophosphamide-induced oxidative stress in rat micturition reflexes. ScientificWorldJournal 2015:545048|
|Vizzard, Margaret A (2015) Pannexins: the 'nexus' between urothelium ATP production and extracellular release. J Physiol 593:1759-60|
|Mingin, Gerald C; Heppner, Thomas J; Tykocki, Nathan R et al. (2015) Social stress in mice induces urinary bladder overactivity and increases TRPV1 channel-dependent afferent nerve activity. Am J Physiol Regul Integr Comp Physiol 309:R629-38|
|Vizzard, Margaret A (2014) New modulatory pathways in micturition reflex function. J Urol 192:638-9|
|Gonzalez, Eric J; Merrill, Liana; Vizzard, Margaret A (2014) Bladder sensory physiology: neuroactive compounds and receptors, sensory transducers, and target-derived growth factors as targets to improve function. Am J Physiol Regul Integr Comp Physiol 306:R869-78|
|Zvarova, K; Herrera, G M; May, V et al. (2014) Cocaine- and amphetamine-regulated transcript peptide (CARTp): distribution and function in rat urinary bladder. J Mol Neurosci 54:351-9|
|Mingin, Gerald C; Peterson, Abbey; Erickson, Cuixia Shi et al. (2014) Social stress induces changes in urinary bladder function, bladder NGF content, and generalized bladder inflammation in mice. Am J Physiol Regul Integr Comp Physiol 307:R893-900|
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