CONICET | Buscador de Institutos y Recursos Humanos

ntroduction: chronic inflammation is linked to several pathologies as diabetes, atherosclerosis and cancer. We demonstrated that the activation of cholinergic system in transformed cells promotes tumor progression. The aim of this work was to study the action of inflammatory stimuli: lypopolisaccharide from E.coli and interferon gamma (LPS+IFN) on muscarinic receptors (mAChR) activation, expressed in normal murine fibroblasts NIH3T3. Methodology: protein expression was assayed by Western blot (Wb) and mAChR activation was studied in cell culture supernatants by measuring nitrite accumulation (uM) by Griess reaction and prostaglandin E2 (PGE2) (pg/ml) liberation by radioimmunoassay. Results: by Wb we confirmed that the addition of LPS+IFN increased CD40 expression in NIH3T3 cells and stimulated nitrite and PGE2 production in a concentration-dependent manner. The maximal effective combination of LPS 10 ng/ml+IFN 0.5 ng/ml increased nitrite production (12.40±0.59) and PGE2 liberation (952±43) in comparison to cells without treatment (4.95±048 and 213±19 respectively; p<0.001). By Wb we confirmed up-regulation of nitric oxide synthase 1 and cyclooxygenase 2 in LPS+IFN treated cells in comparison with untreated cells. The addition of the muscarinic agonist carbachol (CARB) significantly increased both nitrite accumulation and PGE2 production at 10-9M in LPS+IFN treated cells and at 10-8M in untreated cells (p<0.05). The action of CARB on nitrite and PGE2 liberation was reduced by atropine (10-5M) either in treated (LPS+IFN) or in untreated cells. Conclusion: NIH3T3 cells treated with inflammatory stimuli stimulated nitric oxide and PGE2 production by increasing muscarinic sensitivity. UBACYT MO04; Fundación Roemmers.