Involvement of GLWamide neuropeptides in polyp contraction of the adult stony coral Euphyllia ancora

Shinya Shikina,Ching-Fong Chang,Tai-Yu Liu,Céline Zatylny-Gaudin,Yi-Ling Chiu,Yan Zhang,Pin-Hsuan Tsai,Yi-Chenyao Yi-Chenyao

doi:10.1038/s41598-020-66438-3

Shinya Shikina, Ching-Fong Chang + Show 6 more

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https://doi.org/10.1038/s41598-020-66438-3

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Abstract

The existence and function of neurons remain largely unexplored in scleractinian corals. To gain a better understanding of neuronal functions in coral physiology, this study focused on Glycine-Leucine-Tryptophan-amide family neuropeptides (GLWamides), which have been shown to induce muscle contraction and larval metamorphosis in other cnidarians. Molecular identification and functional characterization of GLWamides in the adult stony coral Euphyllia ancora were performed. We successfully elucidated the full-length cDNA of GLWamide preprohormone in E. ancora (named EaGLW preprohormone). The deduced amino acid sequence was predicted to contain six potential GLWamide peptides. Tissue distribution analysis demonstrated that transcripts of EaGLW preprohormone were mainly expressed in the mouth (including the pharynx) and tentacles of the polyps. Immunodetection with an anti-GLWamide monoclonal antibody revealed that GLWamide neurons were mainly distributed in the epidermis of the mouth region and tentacle, in agreement with the distribution patterns of the transcripts. Treatment of the isolated mouth and tentacles with synthetic GLWamide peptides induced the contraction of these isolated tissues. Treatment of polyps with synthetic GLWamide peptides induced the contraction of polyps. These results suggest that GLWamides are involved in polyp contraction (myoactivity) in adult scleractinians. Our data provide new information on the physiological function of neuropeptides in scleractinians.

Highlights

The existence and function of neurons remain largely unexplored in scleractinian corals
The full-length cDNA for EaGLWamide preprohormone determined by rapid amplification of cDNA ends (RACE)-PCR was 1,231 bp in length and contained an open reading frame of 780 bp corresponding to 260 amino acids (Fig. S1)
With the advantages of E. ancora, this study successfully revealed a full-length cDNA sequence encoding GLWamide preprohormone and investigated the spatial distribution patterns of its transcripts in the polyps of both sexes

Summary

Introduction

The existence and function of neurons remain largely unexplored in scleractinian corals. To gain a better understanding of neuronal functions in coral physiology, this study focused on Glycine-LeucineTryptophan-amide family neuropeptides (GLWamides), which have been shown to induce muscle contraction and larval metamorphosis in other cnidarians. Seven types of GLWamides were later isolated from Hydra magnipapillata[10] Some of these GLWamides have been demonstrated to be involved in a wide range of physiological functions, such as larval metamorphosis[11], muscle contraction (myoactivity)[12], polyp detachment[10], and oocyte maturation and ovulation[2,13], in cnidarians. The mature GLWamides identified in cnidarians to date generally range from 5 to 14 amino acids in length and likely possess conserved structural features in their N- and C-terminal regions[2,8]. In adult A. millepora, the transcript expression of GLWamide preprohormone was detected by transcriptome analysis[22], the spatial distribution of GLWamide neurons and its physiological function remain unknown

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