Patients with inflammatory bowel disease often experience overactive bladder reflecting sensory hypersensitivity;however the mechanism underlying this clinical syndrome is not clear. Studies from our laboratory and others indicate that animal models of colitis demonstrate a similar cross-sensitization that leads to neurogenic bladder overactivity. Neuronal interaction at the level of primary afferents in dorsal root ganglia (DRG) and spinal cord likely plays a role in the colon-to-bladder hypersensitivity. The objective of this proposal is to investigate the role of neurotrophins as mediators of primary afferent cross-activation and hypersensitivity in colon-to-bladder sensitization following colitis induced by intracolonic instillation of tri-nitrobenzene sulfonic acid (TNBS) in rat. Our hypothesis is that colitis induces neuronal interaction between afferent neurons in DRG that is initiated, in part, by increases in nerve growth factor (NGF)/TrkA receptor and associated signaling pathways in colonic afferent neurons. This leads to increased expression of brain-derived neurotrophic factor (BDNF) in colonic afferents and increases in BDNF and TrkB in bladder afferent neurons. The increases in BDNF/TrkB and associated signaling pathways lead to subsequent induction of the excitatory neurotransmitter calcitonin gene-related peptide (CGRP) in bladder afferent neurons;BDNF and CGRP, in turn, lead to altered channel expression which mediates in part the hypersensitivity of bladder afferent neurons.
The specific aims are: 1) characterization of NGF/TrkA and signaling pathway(s) in colonic afferent neurons that lead to the expression of BDNF in lumbosacral DRG following colitis;2) characterization of BDNF/TrkB and signaling pathways that lead to the expression of CGRP and ion channel(s) in bladder afferent neurons in DRG following colitis;and 3) characterization of the effects of BDNF and CGRP on the regulation of bladder hypersensitivity as measured by channel activity of bladder afferent neurons as well as bladder micturition parameters following colitis. The experiments will be done with a systematic approach involving measurements of neurotrophins, neuropeptides, and expression of their receptors and signaling pathways by direct measurements of signaling intermediates and use of antagonists, antisera, and selective inhibitors. The investigation of the mechanism underlying neuronal control of bladder and colon function in inflammation will advance understanding of this syndrome as well as suggest approaches for better control or treatment.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK077917-05
Application #
8257168
Study Section
Clinical and Integrative Gastrointestinal Pathobiology Study Section (CIGP)
Program Officer
Hamilton, Frank A
Project Start
2008-04-01
Project End
2013-03-31
Budget Start
2012-04-01
Budget End
2013-03-31
Support Year
5
Fiscal Year
2012
Total Cost
$292,070
Indirect Cost
$96,050
Name
Virginia Commonwealth University
Department
Physiology
Type
Schools of Medicine
DUNS #
105300446
City
Richmond
State
VA
Country
United States
Zip Code
23298
Hashmi, Fiza; Liu, Miao; Shen, Shanwei et al. (2016) EXPRESS: Phospholipase C gamma mediates endogenous brain-derived neurotrophic factor - regulated calcitonin gene-related peptide expression in colitis - induced visceral pain. Mol Pain 12:
Qiao, L Y; Shen, S; Liu, M et al. (2016) Inflammation and activity augment brain-derived neurotrophic factor peripheral release. Neuroscience 318:114-21
Xia, Chunmei; Shen, Shanwei; Hashmi, Fiza et al. (2016) Colitis-induced bladder afferent neuronal activation is regulated by BDNF through PLCγ pathway. Exp Neurol 285:126-135
Liu, Miao; Kay, Jarren C; Shen, Shanwei et al. (2015) Endogenous BDNF augments NMDA receptor phosphorylation in the spinal cord via PLCγ, PKC, and PI3K/Akt pathways during colitis. J Neuroinflammation 12:151
Liu, Miao; Shen, Shanwei; Kendig, Derek M et al. (2015) Inhibition of NMDAR reduces bladder hypertrophy and improves bladder function in cyclophosphamide induced cystitis. J Urol 193:1676-83
Shen, Shanwei; Xia, Chun-Mei; Qiao, Li-Ya (2015) The urinary bladder of spontaneously hypertensive rat demonstrates bladder hypertrophy, inflammation, and fibrosis but not hyperplasia. Life Sci 121:22-7
Qiao, Zhongwei; Xia, Chunmei; Shen, Shanwei et al. (2014) Suppression of the PI3K pathway in vivo reduces cystitis-induced bladder hypertrophy and restores bladder capacity examined by magnetic resonance imaging. PLoS One 9:e114536
Qiao, Li-Ya (2014) Neurotrophin signaling and visceral hypersensitivity. Front Biol (Beijing) 9:216-224
Kay, Jarren C; Xia, Chun-Mei; Liu, Miao et al. (2013) Endogenous PI3K/Akt and NMDAR act independently in the regulation of CREB activity in lumbosacral spinal cord in cystitis. Exp Neurol 250:366-75
Qiao, Li-Ya; Yu, Sharon J; Kay, Jarren C et al. (2013) In vivo regulation of brain-derived neurotrophic factor in dorsal root ganglia is mediated by nerve growth factor-triggered Akt activation during cystitis. PLoS One 8:e81547

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