Muscarinic acetylcholine receptors regulate inflammatory responses through arginases 1/2 in zebrafish

Muscarinic acetylcholine receptors (mAChRs) are widely expressed in various effector cells and have been proved to play vital roles in smooth muscle contraction and digestive secretion. However, there are relatively few literatures revealing the roles of mAChRs in inflammatory processes, and its underlying regulatory mechanisms have not been elucidated. Taking the advantages of live imaging of zebrafish, we found that inhibition of mAChRs resulted in increased neutrophils recruitment and proinflammatory cytokines expression, whereas activation of mAChRs led to opposite outcome. Subsequently, we found that mAChRs regulated the expression of arginases (args), and pharmacological intervention of args level could reverse the effects of mAChRs on neutrophils migration and cytokines expression, suggesting that args are important downstream proteins of mAChRs that mediate the regulation of inflammatory response. In this study, we identified args as novel downstream proteins of mAChRs in inflammatory responses, providing additional evidence for system immune regulation of cholinergic receptors.