Evolution of neuropeptide signalling systems

Abstract

Neuropeptides are a diverse class of neuronal signalling molecules that regulate physiological processes and behaviour in animals. However, determining the relationships and evolutionary origins of the heterogeneous assemblage of neuropeptides identified in a range of phyla has presented a huge challenge for comparative physiologists. Here, we review revolutionary insights into the evolution of neuropeptide signalling that have been obtained recently through comparative analysis of genome/transcriptome sequence data and by ‘deorphanisation’ of neuropeptide receptors. The evolutionary origins of at least 30 neuropeptide signalling systems have been traced to the common ancestor of protostomes and deuterostomes. Furthermore, two rounds of genome duplication gave rise to an expanded repertoire of neuropeptide signalling systems in the vertebrate lineage, enabling neofunctionalisation and/or subfunctionalisation, but with lineage-specific gene loss and/or additional gene or genome duplications generating complex patterns in the phylogenetic distribution of paralogous neuropeptide signalling systems. We are entering a new era in neuropeptide research where it has become feasible to compare the physiological roles of orthologous and paralogous neuropeptides in a wide range of phyla. Moreover, the ambitious mission to reconstruct the evolution of neuropeptide function in the animal kingdom now represents a tangible challenge for the future.

The Link between Autotomy and CNS Regeneration: Echinoderms as Non‐Model Species for Regenerative Biology

“…The starfish-specific neuropeptide (SALMFamide-1 [S1]) is richly expressed in the axonal layer (Figure 4A) and is an excellent marker to document regeneration. [1,25] The cell and tissue events of wound healing, repair, and regeneration are well characterized in starfish and other echinoderms. [13] Within hours of autotomy in C. muricata, the wound site is covered by epithelium (reepithelialization).…”

A G-protein-coupled receptor mediates neuropeptide-induced oocyte maturation in the jellyfish Clytia

“…Much progress has been made in understanding the relationships between GPCR-neuropeptide families between protostomes and deuterostomes [20,25,28,35,36], and more recently with those in acoels and cnidarians [37]. We performed sequence-similarity based clustering to explore the relationship of the Clytia MIHR sequence with known GPCR families in Bilateria using established datasets from human and the annelid Platynereis [25,28 Fig.…”

“…Neuropeptides such as these are of major importance in cnidarian biology, acting both as "neuroendocrine" mediators of physiological transitions such as metamorphosis, as well as in fast neuromuscular transmission regulating swimming and feeding mediated by ligand-gated ion channels [reviewed by 17,18]. We uncovered an oocyte-expressed Class A GPCR in Clytia (MIHR) activated by MIH peptides, which is to our knowledge the first characterized cnidarian neuropeptide GPCR [19,20]. Antibody inhibition experiments further provided evidence that Gα s links MIHR activation to cAMP production to trigger maturation [21,22].…”

A nemertean excitatory peptide/CCHamide regulates ciliary swimming in the larvae of Lineus longissimus

“…This peptide is so far only known from protostomes and has a similar propeptide structure as EP/CCHamide and possesses two cysteine residues (2,60). The relationship of the L11 and EP/CCHamide/neuromedin B receptors, however, has only been weakly supported in phylogenetic analysis (60) or has not been recognized at all (1,15). If these peptidergic systems are indeed ancient paralogs, then at least the cysteines and the propeptide structure seem to be characteristics of their common ancestor.…”