Acylation-stimulating protein (ASP), produced through activation of the alternative complement immune system, modulates lipid metabolism. Using a trans-well co-culture cell model, the mitigating role of 7-nicotinic acetylcholine receptor (7nAChR)-mediated cholinergic pathway on ASP resistance was evaluated. ASP signaling in adipocytes via its receptor C5L2 and signaling intermediates Gq, G, phosphorylated protein kinase C-, and protein kinase C- were markedly suppressed in the presence of TNF or medium from palmitate-treated RAW264.7 macrophages, indicating ASP resistance. There was no direct effect of 7nAChR activation in 3T3-L1 cell culture. However, 7nAChR activation almost completely reversed the ASP resistance in adipocytes co-cultured with palmitate-treated RAW264.7 macrophages. Further, 7nAChR activation could suppress the production of pro-inflammatory molecules TNF and interleukin-6 produced from palmitate-treated co-cultured macrophages. These results suggest that macrophages play a significant role in the pathogenesis of ASP resistance and 7nAChR activation secondarily improves adipose ASP resistance through suppression of inflammation in macrophages. Impact statement 1.Adipocyte-macrophage interaction in acylation-stimulating protein (ASP) resistance 2.Lipotoxicity induced inflammatory response in ASP resistance 3.A vicious circle between lipotoxicity and inflammatory response in ASP resistance 4.Cholinergic modulation of inflammatory response in adipocyte and macrophage