Mechanisms of neuropeptidergic regulation of larval settlement behavior in the marine worm, Platynereis dumerilii
Developmental Biology
Final Report Abstract
Through our investigation of the neuropeptidergic signalling networks in the Platynereis larval anterior nervous system (ANS), we revealed a surprisingly complex chemical connectome acting in the larva that overlays synaptic signalling. This discovery, facilitated by the advent of new technologies including single cell RNA-Seq and largescale receptor deorphanization, led us to explore further the evolution of neuropeptide signalling and its role in animal nervous systems. The cellular-level description of anatomy and signalling in a nerosecretory centre in the anterior larval brain of the marine polychaete Platynereis demonstrates the importance and complexity of neuropeptide signalling and shows how neuropeptides act as modulators of nervous system signalling to generate different behavioural outputs in larvae. We developed a novel approach combining classical connectomics with peptidergic connectomes generated from single cell RNA-Seq data. This analysis enables a more complete understanding of nervous system signalling in animals and is broadly applicable to similar datasets in any organism. Our collaborative discovery of a MIP-gated ion channel (MGIC) is the first peptide-gated ion channel to be activated by a neuropeptide other than FMRFamide. This discovery suggests a larger diversity of peptide-gated channels exists than is currently known. An exciting future avenue will be to use a broader sampling of lophotrochozoan taxa and reconstruct the evolution of ligand specificities of FMRFamideactivated sodium channels (FaNaCs) and MGICs. Finally, the results of our study of neuropeptide-like signalling in a placozoan show that this type of signalling can be used to coordinate complex behaviours in multicellular organisms, even in the absence of neurons.
Publications
- 2016. Towards a systems-level understanding of development in the marine annelid Platynereis dumerilii. Current Opinion in Genetics and Development, 39: 175 - 181
Williams EA, Jékely G
(See online at https://doi.org/10.1016/j.gde.2016.07.005) - 2017. Synaptic and peptidergic connectome of a neurosecretory center in the annelid brain. eLife 2017;6:e26349
Williams EA, Verasztó C, Jasek S, Conzelmann M, Shahidi R, Bauknecht P, Mirabeau O, Jékely G
(See online at https://doi.org/10.7554/eLife.26349) - 2018. Dual signaling of Wamide myoinhibitory peptides through a peptide-gated channel and a GPCR in Platynereis. The FASEB Journal, 32(10):5338-5349
Schmidt A, Bauknecht P, Williams EA, Augustinowski K, Gründer S, Jékely G
(See online at https://doi.org/10.1096/fj.201800274R) - 2018. High cell diversity and complex peptidergic signalling underlie placozoan behaviour. Current Biology 28: 3495 - 3501
Varoqueaux F, Williams EA, Truscello L, Grandemange S, Kamm K, Schierter B, Jékely G, Fasshauer D
(See online at https://doi.org/10.1016/j.cub.2018.08.067)
