title: VEGF signaling mediates bladder neuroplasticity and inflammation in response to BCG.
abstract: BACKGROUND
  This work tests the hypothesis that increased levels of vascular endothelial growth factor (VEGF) observed during bladder inflammation modulates nerve plasticity.
  
  
  METHODS
  Chronic inflammation was induced by intravesical instillations of Bacillus Calmette-Guérin (BCG) into the urinary bladder and the density of nerves expressing the transient receptor potential vanilloid subfamily 1 (TRPV1) or pan-neuronal marker PGP9.5 was used to quantify alterations in peripheral nerve plasticity. Some mice were treated with B20, a VEGF neutralizing antibody to reduce the participation of VEGF. Additional mice were treated systemically with antibodies engineered to specifically block the binding of VEGF to NRP1 (anti-NRP1B) and NRP2 (NRP2B), or the binding of semaphorins to NRP1 (anti-NRP1 A) to diminish activity of axon guidance molecules such as neuropilins (NRPs) and semaphorins (SEMAs). To confirm that VEGF is capable of inducing inflammation and neuronal plasticity, another group of mice was instilled with recombinant VEGF165 or VEGF121 into the urinary bladder.
  
  
  RESULTS
  The major finding of this work was that chronic BCG instillation resulted in inflammation and an overwhelming increase in both PGP9.5 and TRPV1 immunoreactivity, primarily in the sub-urothelium of the urinary bladder. Treatment of mice with anti-VEGF neutralizing antibody (B20) abolished the effect of BCG on inflammation and nerve density.NRP1A and NRP1B antibodies, known to reduce BCG-induced inflammation, failed to block BCG-induced increase in nerve fibers. However, the NRP2B antibody dramatically potentiated the effects of BCG in increasing PGP9.5-, TRPV1-, substance P (SP)-, and calcitonin gene-related peptide (CGRP)-immunoreactivity (IR). Finally, instillation of VEGF121 or VEGF165 into the mouse bladder recapitulated the effects of BCG and resulted in a significant inflammation and increase in nerve density.
  
  
  CONCLUSIONS
  For the first time, evidence is being presented supporting that chronic BCG instillation into the mouse bladder promotes a significant increase in peripheral nerve density that was mimicked by VEGF instillation. Effects of BCG were abolished by pre-treatment with neutralizing VEGF antibody. The present results implicate the VEGF pathway as a key modulator of inflammation and nerve plasticity, introduces a new animal model for investigation of VEGF-induced nerve plasticity, and suggests putative mechanisms underlying this phenomenon.
authors: Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
authors: Marcia R
authors: MR
authors: Saban
authors: Carole A
authors: CA
authors: Davis
authors: Antonio
authors: A
authors: Avelino
authors: Francisco
authors: F
authors: Cruz
authors: Julie
authors: J
authors: Maier
authors: Dale E
authors: DE
authors: Bjorling
authors: Thomas J
authors: TJ
authors: Sferra
authors: Robert E
authors: RE
authors: Hurst
authors: Ricardo
authors: R
authors: Saban
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology; D001500:BCG Vaccine / Q000276:immunology / Q000494:pharmacology*; D002116:Calcitonin / Q000276:immunology / Q000378:metabolism; D005260:Female; D007249:Inflammation / Q000139:chemically induced / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009473:Neuronal Plasticity / Q000187:drug effects* / Q000276:immunology; D039942:Neuropilin-1 / Q000276:immunology / Q000378:metabolism; D039943:Neuropilin-2 / Q000276:immunology / Q000378:metabolism; D039921:Neuropilins / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D011498:Protein Precursors / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D039961:Semaphorins / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction; D013373:Substance P / Q000276:immunology / Q000378:metabolism; D050916:TRPV Cation Channels / Q000276:immunology / Q000378:metabolism; D043222:Ubiquitin Thiolesterase / Q000276:immunology / Q000378:metabolism; D001743:Urinary Bladder / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D019459:Urothelium / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: D057134:Antibodies, Neutralizing; D001500:BCG Vaccine; D039943:Neuropilin-2; D039921:Neuropilins; D011498:Protein Precursors; D011994:Recombinant Proteins; D039961:Semaphorins; D050916:TRPV Cation Channels; C493921:TRPV1 protein, mouse; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D039942:Neuropilin-1; D013373:Substance P; D002116:Calcitonin; D043222:Ubiquitin Thiolesterase; C496976:Uchl1 protein, mouse