PROJECT SUMMARY The contribution of the autonomic nervous system to the development of inflammation is an important new subject that has massive potential for clinical applications. It has been demonstrated that α7 nicotinic acetylcholine receptor (α7nAChR) is a critical component of anti-inflammatory cholinergic pathway that protects an organism during infection, arthritis, diabetes and atherosclerosis. So far, the protective role of α7nAChR was established only on the prevention of expression of pro-inflammatory cytokines, such as TNFα and IL-6. However, the mechanism of α7nAChR contribution to inflammatory response seems to be more comprehensive. One of the most critical steps of the inflammatory response is macrophage migration to the site of inflammation. The goal of this project is to determine the mechanism of macrophage migration regulated by the autonomic nervous system. We hypothesize that α7nAChR activation affects macrophage migration during inflammation by changing the expression of cell adhesive receptors, that modifies the overall α7nAChR- mediated anti-inflammatory response. Guided by strong preliminary data, this hypothesis will be tested by pursuing three Specific Aims: 1. Determine the contribution of α7nAChR to macrophage accumulation within the site of inflammation utilizing in vivo inflammatory models. 2. Evaluate the effect of α7nAChR on macrophage adhesion and migration using in vitro assays. 3. Define the critical molecules that regulate α7nAChR-mediated leukocyte migration. Under the first aim, the effect of α7nAChR-deficientcy on macrophage accumulation during endotoxemia and atherosclerosis will be evaluated. Under the second aim, the contribution of α7nAChR to macrophage motility will be assessed using in vitro adhesion and migration assays. Under the third aim, α7nAChR-dependent expression of adhesion and chemokine receptors on macrophages will be evaluated and analyzed. The significance of our study resides in providing a new insight into the function of neuro-immune synapse during inflammation. The direct contribution of α7nAChR cholinergic receptor to monocyte/macrophage migration proposes a new mechanism for the regulation of inflammatory response though the vagus nerve. This proposal is innovative because most studies of cholinergic anti- inflammatory mechanisms have focused on the ability of nicotinic agonists to suppress the synthesis and release of inflammatory cytokines from activated macrophages. We propose the role of neuro-immune synapse in macrophage migration. The results of our studies will provide completely new information regarding the role of α7nAChR in inflammation. These findings will be of significant therapeutic interest for targeting α7nAChR to regulate macrophage migration and to control inflammation in several disorders. The development of anti- inflammatory treatments is an objective of our further investigations.