Neuronal octopamine signaling regulates mating-induced germline stem cell increase in female Drosophila melanogaster

Stem cells fuel the development and maintenance of
tissues. Many studies have addressed how local signals from
neighboring niche cells regulate stem cell identity and their
proliferative potential. However, the regulation of stem cells by
tissue-extrinsic signals in response to environmental cues remains poorly
understood. Here we report that efferent octopaminergic neurons
projecting to the ovary are essential for germline stem cell (GSC)
increase in response to mating in female Drosophila. The neuronal
activity of the octopaminergic neurons is required for mating-induced GSC
increase as they relay the mating signal from Sex peptide
receptor-positive cholinergic neurons. Octopamine and its receptor Oamb
are also required for mating-induced GSC increase via intracellular
Ca2+ signaling. Moreover, we identified Matrix
metalloproteinase-2 as a downstream component of the
octopamine-Ca2+ signaling to induce GSC increase. Our study
provides a mechanism describing how neuronal system couples stem cell
behavior to environmental cues through stem cell niche signaling.