CONICET | Buscador de Institutos y Recursos Humanos

We demonstrated the presence of muscar¨ªnic receptors M3, M4 and M5 receptors, and choline acetyltransferase and acetylcholinesterase enzymes in human dendritic cells (DC). Given that the maturation process of the DC has a central role in the immune response, we investigated the effect of cholinergic stimulation on the expression of maturation markers and the proinflammatory cytokines. DC were differentiated from positive selected CD14+ cells isolated from peripheral blood mononuclear cells and cultured with IL-4 and GM-CSF. Then cells were treated with the cholinergic agonist carbachol (Carb,10-8M) for 1h followed by additional 24h in the absence (immature(iDC)) or presence (mature(mDC)) of LPS (0.5mg/ml). We observed that Carb increased the expression of HLA-DR and CD86, as well as the production of IL-12 (Carb:575¡À10; baseline:374¡À15(pg/ml)) and TNF-¦Á (Carb:6733¡À1167, baseline:3667¡À629) in mDC (n=3, P¡Ü0.01). Both effects were reduced in the presence of the muscarinic antagonist atropine (10-7M). Nitric oxide synthase (NOS) isoforms are involved in the signaling pathway of M3 and M5 receptors and their product, nitric oxide, is an inflammatory mediator and an immune response regulator. We have shown by Western blot that iDC as well as mDC expressed NOS1 and NOS3 and had similar basal release of NO2-(uM) (iDC:2.99¡À0.96; mDC:1.98¡À0.51). Carb treatment increased the levels of NO2- in iDC. We concluded that cholinergic stimulation regulates the expression of phenotypic markers of maturation and production of proinflammatory cytokines in human DC. iDC also respond to the cholinergic agonist, increasing their nitric oxide production, which could be a key factor in the maturation process.