The evolution of neuropeptide signalling: insights from echinoderms

Area of Science:

• Evolutionary Biology
• Neuroscience
• Genomics

Background:

• Neuropeptides are ancient signaling molecules regulating diverse physiological processes and behaviors across the animal kingdom.
• Previous research on neuropeptide evolution primarily focused on vertebrates and protostomian invertebrates, with limited data from non-ecdysozoan invertebrates.
• Echinoderms, as deuterostomes, offer a unique perspective for understanding evolutionary relationships of neuropeptide signaling systems.

Purpose of the Study:

• To investigate the evolutionary history and diversity of neuropeptide signaling systems in echinoderms.
• To identify novel neuropeptide precursors and their evolutionary connections to known systems in other animal groups.
• To explore the functional implications of neuropeptide signaling in echinoderms with decentralized nervous systems.

Main Methods:

• Genome sequencing of the sea urchin Strongylocentrotus purpuratus.
• Neural transcriptome sequencing of the starfish Asterias rubens.
• Bioinformatic analysis to identify and characterize neuropeptide precursors.

Main Results:

• Discovery of the first invertebrate thyrotropin-releasing hormone-type precursor in S. purpuratus.
• Identification of the first deuterostomian pedal peptide/orcokinin-type precursors and NG peptides in S. purpuratus, linking vertebrate and protostome systems.
• Characterization of 40 neuropeptide precursors in A. rubens, including novel kisspeptin and melanin-concentrating hormone-type precursors outside of chordates, and a corazonin-type system providing insights into GnRH evolution.

Conclusions:

• Echinoderms possess a rich diversity of neuropeptide signaling systems, providing critical missing links in our understanding of neuropeptide evolution.
• The findings highlight the importance of non-ecdysozoan invertebrates for reconstructing the evolutionary history of neuronal communication.
• Future research in echinoderms can elucidate how these ancient signaling systems regulate physiology and behavior within their unique body plan.