Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) Is Released by Female Mouse Bladder Urothelial Cells and Expressed by the Urotheliumas an Early Response to Lipopolysaccharides (LPS)
Authors
Yan Li, Ming Lu, Lery Alvarez-Lugo, Gang Chen, and Toby C. Chai
Institution
Jinshan Hospital
Country
China
Year
2016
Journal
Neurourology and Urodynamics
Abstract
We studied in vitro and in vivo response of primary mouse bladder urothelial cells (mBUC) and bladder
urothelium to lipopolysaccharides (LPS), focusing on granulocyte-macrophage colony-stimulating factor (GM-CSF)
signaling. Methods: Female C57BL/6 mBUC were exposed for 12 hr to differing concentrations of LPS (100 ng/ml to
10 mg/ml). mBUC were also exposed to a single dose of LPS (1 mg/ml) for 3, 6, 12 hr. Neutralizing GM-CSF antibody
(0.1mg/ml) was used block GM-CSF activity in vitro. In vivo experiments were performed, whereby, LPS (1 mg/ml) was
instilled intravesically and left to dwell for 30 min followed by harvest of bladder urothelium 3 to 18 hr later. ELISA
measured GM-CSF. qPCR quantitated mRNA for GM-CSF, vascular endothelial growth factor-A (VEGF-A),
cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and tumor necrosis factor a (TNF-a). RT-PCR was used to detect
mRNA for GM-CSF, GM-CSFRa, and b in bladder tissues. Immunohistofluorescence and Western blots for GM-CSFRa
were performed on bladder tissues. Results: LPS induced a dose-dependent release of GM-CSF by mBUC. Mouse
bladder urothelium did not express GM-CSF mRNA at baseline, but expressed GM-CSF mRNA 3 hr after in vivo LPS
exposure, with GM-CSF mRNA expression disappearing 18 hr later. GM-CSFRa expression was confirmed in bladder
urothelium. GM-CSF neutralizing antibody significantly diminished LPS-induced increases of VEGF and COX-2 mRNA
expression. Conclusions: Urothelium and mBUC secreted GM-CSF as an early response to LPS. GM-CSF mediated
downstream expression of VEGF and COX-2. Urothelial GM-CSF may function as a signaling mediator for both
inflammation and pain transduction.