Role of Nicotinic and Estrogen Signaling during Experimental Acute and Chronic Bladder Inflammation

Magaly Martinez-Ferrer^*, Juan M. Iturregui, Consolate Uwamariya^*, Jonathan Starkman^*, Ali-Reza Sharif-Afshar^*, Kichiya Suzuki^*, Wit Visedsindh^*, Robert J. Matusik^*, Roger R. Dmochowski^* and Neil A. Bhowmick^*

From the Departments of Urologic Surgery ^*and Pathology,Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee

Inflammation is a physiological process that characterizes manybladder diseases. We hypothesized that nicotinic and estrogensignaling could down-regulate bladder inflammation. Cyclophosphamidewas used to induce acute and chronic bladder inflammation. Changesin bladder inflammation were measured histologically and byinflammatory gene expression. Antagonizing nicotinic signalingwith mecamylamine further aggravated acute and chronic inflammatorychanges resulting from cyclophosphamide treatment. Estrogenand nicotinic signaling independently attenuated acute bladderinflammation by decreasing neutrophil recruitment and down-regulatingelevated lipocalin-2 and cathepsin D expression. However, thecombined signaling by the estrogen and nicotinic pathways, asmeasured by macrophage infiltration and up-regulation of interleukin-6expression in the bladder, synergistically reduced chronic bladderinflammation. The elevated expression of p65 nuclear localizationin bladders treated with cyclophosphamide or cyclophosphamidewith mecamylamine suggested nuclear factor- ${kappa}$ B activation in thechronic inflammatory process. The complementary treat-ment of17β-estradiol and the nicotinic agonist anabasine resultedin the translocation of p65 to the cytoplasm, again greaterthan either alone. Activation of nuclear factor- ${kappa}$ B can resultin macrophage activation and/or elevation in epithelial proliferation.These data suggest that 17β-estradiol and anabasine reducechronic bladder inflammation through reduction of nuclear translocationof p65 to suppress cytokine expression.