CONICET | Buscador de Institutos y Recursos Humanos

The non-neuronal cholinergic system is constituted by acetylcholine (Ac), enzymes that synthesize and degrade it, choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) respectively, and nicotinic and muscarinic (M) receptors. Recently, we demonstrated the presence of M3, M4 and M5 receptors, and ChAT and AChE enzymes in human dendritic cells (DC). Given that the maturation process of the DC have a central role in the immune response, here we investigated the effect of cholinergic stimulation on the expression of maturation markers: HLA-DR and CD86 and the proinflammatory cytokines production, such as IL-12 and TNF-¦Á, in these cells. DC were differentiated from positive selected CD14+ cells isolated from peripheral blood mononuclear cells and cultured with IL-4 and GM-CSF during 5 days. Then cells were treated with the cholinergic agonist carbachol (Carb, 10-8M) for 1 h followed by additional 24 h in the absence (immature DC (iDC)) or presence (mature DC (mDC)) of LPS (0.5 mg / ml). We observed that Carb increased the expression of HLA-DR and CD86, as well as the production of IL-12 (Carb: 575 ¡À 10; baseline: 374 ¡À 15(pg / ml)) and TNF-¦Á (Carb: 6733 ¡À 1167, 3667¡À 629 baseline) in mDC (n = 3, P ¡Ü 0.01 Carb. vs. baseline). 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 isoforms and had similar basal release of NO2-(uM) (iDC: 2.99 ¡À 0.96; mDC 1.98 ¡À 0.51). Carb treatment increased the levels of NO2-(5.53 ¡À 0.18, p