Investigating the role of cholinergic signaling in Drosophila melanogaster defense against bacterial pathogens

Cholinergic signaling takes place at synapses to mediate neurotransmission in animals, but is also implicated in different cell-to-cell communication mechanisms that operate in non-neuronal tissues and play important roles for the maintenance of physiological homeostasis. In humans, acetylcholine is involved in the regulation of immune functions, but information about its immunomodulatory potential in invertebrates is still limited. Since neonicotinoids, neurotoxic insecticides that are able to target insect nicotinic acetylcholine receptors (nAChRs), impair the immune response in both Apis mellifera and Drosophila melanogaster, we decided to investigate the role of acetylcholine signaling in insect defense against pathogens. By using a Gal4-UAS expression system, we altered nAChR function in Drosophila immune tissues and tested if and how these manipulations affected fly survival to systemic infection. The obtained results support the occurrence of acetylcholine-based immune regulation in Drosophila, whose impact may differ depending on the species of invading bacteria.