1
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Shulga UE, Kalachev AV. Hemal sinus basal laminae contact sites: a possible route between gonadal lumen and myoepithelial cells in the gonad of the sea star Patiria pectinifera. PROTOPLASMA 2024:10.1007/s00709-024-01979-2. [PMID: 39141092 DOI: 10.1007/s00709-024-01979-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 08/07/2024] [Indexed: 08/15/2024]
Abstract
Sea stars are a group of marine invertebrates suitable for studying the hormonal regulation of reproduction and spawning. In spite of substantial progress in understanding how various substances such as 1-methyladenine act in their gonads, there are still many gaps concerning the fine details of their action. One such gap is how the gonadal wall contraction is induced. Recent literature data suggest that, upon 1-methyladenine stimulation, some cells within the gonadal lumen produce non-neuronal acetylcholine that, upon contact with the gonadal wall, induces contraction of myoepithelial cells. Our ultrastructural study of the gonads in the sea star Patiria pectinifera has shown, for the first time, that there are sites where the basal laminae bordering the hemal sinus directly contact one another and appear at this contact site as a single entity. These contact sites are often associated with hemidesmosome-like junctions that anchor male accessory cells or female follicle cells on one side of the site and myoepithelial cells on the opposite. We suggest that contraction-inducing substance is secreted from an accessory or follicle cell, passes through a basal lamina contact site, and on the opposite side of the contact site acts on a myoepithelial cell to induce its contraction.
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Affiliation(s)
- Uliana E Shulga
- Far Eastern Federal University, P. Ajax, 10, Russky Island, Vladivostok, 690922, Russia
| | - Alexander V Kalachev
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch of the Russian Academy of Sciences, Ul. Palchevskogo, 17, Vladivostok, 690041, Russia.
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2
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Mita M, Feng Y, Piñon-Gonzalez VM, Elphick MR, Katayama H. Gonadotropic activity of a second relaxin-type peptide in starfish. Gen Comp Endocrinol 2023; 343:114369. [PMID: 37611673 DOI: 10.1016/j.ygcen.2023.114369] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/14/2023] [Accepted: 08/20/2023] [Indexed: 08/25/2023]
Abstract
In starfish, a relaxin-like gonad-stimulating peptide (RGP) acts as a gonadotropin that triggers gamete maturation and spawning. In common with other relaxin/insulin superfamily peptides, RGP consists of an A- and a B-chain, with cross-linkages mediated by one intra- and two inter-chain disulfide bonds. In this study, a second relaxin-like peptide (RLP2) was identified in starfish species belonging to the orders Valvatida, Paxillosida, and Forcipulatida. Like RGP, RLP2 precursors comprise a signal peptide and a C-peptide in addition to the A- and B-chains. However, a unique cysteine motif [CC-(3X)-C-(10X)-C] is present in the A-chain of RLP2, which contrasts with the cysteine motif in other members of the relaxin/insulin superfamily [CC-(3X)-C-(8X)-C]. Importantly, in vitro pharmacological tests revealed that Patiria pectinifera RLP2 (Ppe-RLP2) and Asterias rubens RLP2 (Aru-RLP2) trigger shedding of mature eggs from ovaries of P. pectinifera and A. rubens, respectively. Furthermore, the potencies of Ppe-RLP2 and Aru-RLP2 as gonadotropic peptides were similar to those of Ppe-RGP and Aru-RGP, respectively, and the effect of RLP2 exhibited partial species-specificity. These findings indicate that two relaxin-type peptides regulate spawning in starfish and therefore we propose that RGP and RLP2 are renamed RGP1 and RGP2, respectively.
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Affiliation(s)
- Masatoshi Mita
- Department of Biochemistry, Showa University School of Medicine, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
| | - Yuling Feng
- Queen Mary University of London, School of Biological & Behavioural Sciences, Mile End Road, London E1 4NS, UK
| | - Victor M Piñon-Gonzalez
- Queen Mary University of London, School of Biological & Behavioural Sciences, Mile End Road, London E1 4NS, UK
| | - Maurice R Elphick
- Queen Mary University of London, School of Biological & Behavioural Sciences, Mile End Road, London E1 4NS, UK
| | - Hidekazu Katayama
- Department of Bioengineering, School of Engineering, Tokai University, 4-1-1, Kitakaname, Hiratsuka, Kanagawa, 259-1292, Japan
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Mita M. Relaxin-like Gonad-Stimulating Peptides in Asteroidea. Biomolecules 2023; 13:biom13050781. [PMID: 37238650 DOI: 10.3390/biom13050781] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023] Open
Abstract
Starfish relaxin-like gonad-stimulating peptide (RGP) is the first identified peptide hormone with gonadotropin-like activity in invertebrates. RGP is a heterodimeric peptide, comprising A and B chains with disulfide cross-linkages. Although RGP had been named a gonad-stimulating substance (GSS), the purified peptide is a member of relaxin-type peptide family. Thus, GSS was renamed as RGP. The cDNA of RGP encodes not only the A and B chains, but also signal and C-peptides. After the rgp gene is translated as a precursor, mature RGP is produced by eliminating the signal and C-peptides. Hitherto, twenty-four RGP orthologs have been identified or predicted from starfish in the orders Valvatida, Forcipulatida, Paxillosida, Spinulosida, and Velatida. The molecular evolution of the RGP family is in good accordance with the phylogenetic taxonomy in Asteroidea. Recently, another relaxin-like peptide with gonadotropin-like activity, RLP2, was found in starfish. RGP is mainly present in the radial nerve cords and circumoral nerve rings, but also in the arm tips, the gonoducts, and the coelomocytes. RGP acts on ovarian follicle cells and testicular interstitial cells to induce the production of 1-methyladenine (1-MeAde), a starfish maturation-inducing hormone. RGP-induced 1-MeAde production is accompanied by an increase in intracellular cyclic AMP levels. This suggests that the receptor for RGP (RGPR) is a G protein-coupled receptor (GPCR). Two types of GPCRs, RGPR1 and RGPR2, have been postulated as candidates. Furthermore, 1-MeAde produced by RGP not only induces oocyte maturation, but also induces gamete shedding, possibly by stimulating the secretion of acetylcholine in the ovaries and testes. Thus, RGP plays an important role in starfish reproduction, but its secretion mechanism is still unknown. It has also been revealed that RGP is found in the peripheral adhesive papillae of the brachiolaria arms. However, gonads are not developed in the larvae before metamorphosis. It may be possible to discover new physiological functions of RGP other than gonadotropin-like activity.
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Affiliation(s)
- Masatoshi Mita
- Department of Biochemistry, Showa University School of Medicine, Hatanodai 8-5-1, Shinagawa-ku, Tokyo 142-8555, Japan
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4
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Katayama H, Mita M. The C-terminally amidated relaxin-like gonad-stimulating peptide in the starfish Astropecten scoparius. Gen Comp Endocrinol 2023; 334:114226. [PMID: 36731602 DOI: 10.1016/j.ygcen.2023.114226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/26/2023] [Accepted: 01/28/2023] [Indexed: 02/03/2023]
Abstract
A relaxin-like gonad-stimulating peptide (RGP) in starfish was the first identified invertebrate gonadotropin, consisting of A- and B-chain. Recently, an RGP ortholog (Asc-RGP) from Astropecten scoparius in the order Paxillosida was found to harbor an amidation signal (Gly-Arg) at the C-terminus of the B-chain (Mita et al., 2020a). Two cleavage sites were also predicted within the signal peptide of the Asc-RGP precursor. Thus, four kinds of analogs (Asc-RGP-NH2(S), Asc-RGP-GR(S), Asc-RGP- NH2(L), Asc-RGP-GR(L) were hypothesized as natural Asc-RGPs. To identify the natural Asc-RGP, an extract of radial nerve cords from A. scoparius was analyzed using reverse-phase high-performance liquid chromatography and MALDI-TOF-mass spectrometry. The molecular weight of Asc-RGP was 4585.3, and those of A- and B-chains were 2511.8 and 2079.8, respectively. This strongly suggests that natural RGP in A. scoparius is Asc-RGP-NH2(S). Asc-RGP-NH2(S) stimulated 1-methyladenine and cyclic AMP production in isolated ovarian follicle cells of A. scoparius. On the other hand, the concentrations of four synthetic Asc-RGP analogs required for the induction of spawning in 50% of ovarian fragments were almost the same. The size and C-terminal amidation of the B-chain might not be important for spawning-inducing activity. C-terminally amidated RGPs in the B-chain were also observed in other species of starfish belonging to the order Paxillosida, particularly the family Astropectinidae, but not the family Luidiidae.
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Affiliation(s)
- Hidekazu Katayama
- Department of Bioengineering, School of Engineering, Tokai University, 4-1-1, Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
| | - Masatoshi Mita
- Department of Biochemistry, Showa University School of Medicine, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
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5
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Mita M, Katayama H, Yamamoto K, Shibata Y, Kiyomoto M. A Relaxin-Like Gonad-Stimulating Peptide Appears in the Early Development of the Starfish Patiria pectinifera. Zoolog Sci 2023; 40:7-12. [PMID: 36744704 DOI: 10.2108/zs220058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 11/13/2022] [Indexed: 01/18/2023]
Abstract
Relaxin-like gonad-stimulating peptide (RGP) is a hormone with gonadotropin-like activity in starfish. This study revealed that spawning inducing activity was detected in an extract of brachiolaria larvae of Patiria pectinifera. Spawning inducing activity in the extract was due to P. pectinifera RGP (PpeRGP), not 1-methyladenine. The expression of PpeRGP mRNA was also found in brachiolaria. Immunohistochemical observation with specific antibodies for PpeRGP showed that PpeRGP was distributed in the peripheral adhesive papilla of the brachiolaria arms. In contrast, PpeRGP was not detected in the adult rudiment or ciliary band regions, which are present in the neural system. These findings strongly suggest that RGP exists in the larvae before metamorphosis. Because gonads are not developed in starfish larvae, it seems likely that RGP plays another role other than gonadotropic action in the early development of starfish.
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Affiliation(s)
- Masatoshi Mita
- Department of Biochemistry, Showa University School of Medicine, Shinagawa-ku, Tokyo 142-8555, Japan,
| | - Hidekazu Katayama
- Department of Bioengineering, School of Engineering, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
| | - Kazutoshi Yamamoto
- Department of Biology, Faculty of Education and Integrated Sciences, Center for Advanced Biomedical Sciences, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Yasushi Shibata
- Department of Life and Health Science, Faculty of Life & Environmental Sciences, Teikyo University of Science, Uenohara, Yamanashi 409-0193, Japan
| | - Masato Kiyomoto
- Tateyama Marine Laboratory, Marine and Coastal Research Center, Ochanomizu University, Tateyama, Chiba 294-0301, Japan
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Jönsson M, Morin M, Wang CK, Craik DJ, Degnan SM, Degnan BM. Sex-specific expression of pheromones and other signals in gravid starfish. BMC Biol 2022; 20:288. [PMID: 36528687 PMCID: PMC9759900 DOI: 10.1186/s12915-022-01491-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 12/01/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Many echinoderms form seasonal aggregations prior to spawning. In some fecund species, a spawning event can lead to population outbreaks with detrimental ecosystem impacts. For instance, outbreaks of crown-of-thorns starfish (COTS), a corallivore, can destroy coral reefs. Here, we examine the gene expression in gravid male and female COTS prior to spawning in the wild, to identify genome-encoded factors that may regulate aggregation and spawning. This study is informed by a previously identified exoproteome that attracts conspecifics. To capture the natural gene expression profiles, we isolated RNAs from gravid female and male COTS immediately after they were removed from the Great Barrier Reef. RESULTS: Sexually dimorphic gene expression is present in all seven somatic tissues and organs that we surveyed and in the gonads. Approximately 40% of the exoproteome transcripts are differentially expressed between sexes. Males uniquely upregulate an additional 68 secreted factors in their testes. A suite of neuropeptides in sensory organs, coelomocytes and gonads is differentially expressed between sexes, including the relaxin-like gonad-stimulating peptide and gonadotropin-releasing hormones. Female sensory tentacles-chemosensory organs at the distal tips of the starfish arms-uniquely upregulate diverse receptors and signalling molecules, including chemosensory G-protein-coupled receptors and several neuropeptides, including kisspeptin, SALMFamide and orexin. CONCLUSIONS Analysis of 103 tissue/organ transcriptomes from 13 wild COTS has revealed genes that are consistently differentially expressed between gravid females and males and that all tissues surveyed are sexually dimorphic at the molecular level. This finding is consistent with female and male COTS using sex-specific pheromones to regulate reproductive aggregations and synchronised spawning events. These pheromones appear to be received primarily by the sensory tentacles, which express a range of receptors and signalling molecules in a sex-specific manner. Furthermore, coelomocytes and gonads differentially express signalling and regulatory factors that control gametogenesis and spawning in other echinoderms.
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Affiliation(s)
- Mathias Jönsson
- Centre for Marine Science, School of Biological Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Marie Morin
- Centre for Marine Science, School of Biological Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Conan K Wang
- Institute for Molecular Bioscience, ARC Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - David J Craik
- Institute for Molecular Bioscience, ARC Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Sandie M Degnan
- Centre for Marine Science, School of Biological Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Bernard M Degnan
- Centre for Marine Science, School of Biological Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.
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7
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Mita M, Osugi T, Kawada T, Satake H, Katayama H, Kitamura T, Miura T, Miura C. Characterization and localization of relaxin-like gonad-stimulating peptide in the crown-of-thorns starfish, Acanthaster cf. solaris. Gen Comp Endocrinol 2022; 328:114107. [PMID: 35973586 DOI: 10.1016/j.ygcen.2022.114107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 07/27/2022] [Accepted: 08/11/2022] [Indexed: 11/16/2022]
Abstract
In starfish, a relaxin-like gonad-stimulating peptide (RGP) is the gonadotropin responsible for final gamete maturation. RGP comprises two different peptides, A- and B-chains with two interchain and one intrachain disulfide bonds. The existence of two isomers of RGP in the crown-of-thorns starfish, Acanthaster planci, has been reported previously, but it was recently shown that A. planci represents a species complex with four different species. Here we elucidated the authentic sequence of the Pacific species, Acanthaster cf. solaris, RGP (Aso-RGP). The Aso-RGP precursor encoded by a 354 base pair open reading frame was composed of 117 amino acids (aa). The amino acid identity of Aso-RGP to Patiria pectinifera RGP (Ppe-RGP) and Asterias amurensis RGP (Aam-RGP) was 74% and 60%, respectively. Synthetic Aso-RGP induced spawning of ovarian fragments from A. cf. solaris. Ppe-RGP and Aam-RGP also induced spawning by A. cf. solaris ovaries. In contrast, Ppe-RGP and Aso-RGP induced spawning by P. pectinifera ovaries, but Aam-RGP was inactive. Notably, anti-Ppe-RGP antibodies recognized Aso-RGP as well as Ppe-RGP. Localization of Aso-RGP was observed immunohistochemically using anti-Ppe-RGP antibodies, showing that Aso-RGP was mainly present in the radial nerve cords of A. cf. solaris. Aso-RGP was distributed not only in the epithelium of the ectoneural region but also in the neuropile of the ectoneural region. These results suggest that Aso-RGP is synthesized in the epithelium of the ectoneural region, then transferred to fibers in the neuropile of the ectoneural region in radial nerve cords.
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Affiliation(s)
- Masatoshi Mita
- Department of Biochemistry, Showa University School of Medicine, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
| | - Tomohiro Osugi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
| | - Tsuyoshi Kawada
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
| | - Honoo Satake
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
| | - Hidekazu Katayama
- Department of Applied Biochemistry, School of Engineering, Tokai University, 4-1-1, Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
| | - Takaya Kitamura
- The Kuroshio Biological Research Foundation, Nishidomari, Otsuki-cho, Hata-gun, Kochi 788-0333, Japan
| | - Takeshi Miura
- Laboratory of Aquaculture and Livestock Production, The United Graduate School of Agricultural Science, Ehime University, Tarumi 3-5-7, Matuyama-shi, Ehime 790-8566, Japan
| | - Chiemi Miura
- Department of Global Environmental Studies, Faculty of Environmental Studies, Hiroshima Institute of Technology, Miyake 2-1-1, Saeki-ku, Hiroshima 731-5193, Japan
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Are myoepithelial cells confined to genital coelomic sinus in the gonads of sea stars? Tissue Cell 2022; 76:101757. [DOI: 10.1016/j.tice.2022.101757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/20/2022] [Accepted: 02/09/2022] [Indexed: 11/19/2022]
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Mita M, Elphick MR, Katayama H. A specific and sensitive enzyme-linked immunosorbent assay for measurement of relaxin-like gonad-stimulating peptide in the starfish Asterias rubens. Gen Comp Endocrinol 2021; 310:113831. [PMID: 34089706 DOI: 10.1016/j.ygcen.2021.113831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 03/10/2021] [Accepted: 06/01/2021] [Indexed: 11/22/2022]
Abstract
A relaxin-like gonad-stimulating peptide (RGP) acts as a gonadotropic hormone in starfish. In this study, antibodies to Asterias rubens RGP (AruRGP) were used for the development of a specific and sensitive enzyme-linked immunosorbent assay (ELISA) to measure AruRGP. Biotin-conjugated RGP (biotin-AruRGP) that binds to peroxidase-conjugated streptavidin was synthesized chemically so that it could be specifically detected using 3, 3', 5, 5'-tetramethylbenzidine (TMB)/hydrogen peroxide as a substrate. Similar to AruRGP, biotin-AruRGP bound to AruRGP antibodies. In binding experiments with biotin-AruRGP using wells coated with AruRGP antibodies, a displacement curve was obtained using serial dilutions of AruRGP. Using this ELISA system, AruRGP could be measured in the range 0.01-5.0 pmol per 50 µl test solution. Furthermore, 0.22 ± 0.03 and 0.20 ± 0.04 pmol AruRGP/mg wet weight tissue were detected in the radial nerve cords and circumoral nerve-rings of A. rubens, respectively. Smaller amounts of AruRGP were detected in tube feet, pyloric stomach and cardiac stomach but AruRGP was not detected in pyloric caeca, ovaries and testes. Analysis of the specificity of the AruRGP antibodies revealed that the A- and B-chains of AruRGP, Patiria pectinifera RGP, Aphelasterias japonica RGP, and human relaxin exhibit little or no cross-reactivity in the ELISA. We conclude, therefore, that we have successfully generated an ELISA system that is highly sensitive and specific for detection of AruRGP.
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Affiliation(s)
- Masatoshi Mita
- Department of Biochemistry, Showa University School of Medicine, Hatanodai 8-5-1, Shinagawa-ku, Tokyo 142-8555, Japan.
| | - Maurice R Elphick
- Queen Mary University of London, School of Biological & Chemical Sciences, Mile End Road, London E1 4NS, UK
| | - Hidekazu Katayama
- Department of Applied Biochemistry, School of Engineering, Tokai University, 4-1-1, Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
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Delroisse J, Léonet A, Alexandre H, Eeckhaut I. Intracellular Pathways of Holothuroid Oocyte Maturation Induced by the Thioredoxin Trx-REES. Antioxidants (Basel) 2021; 10:1201. [PMID: 34439448 PMCID: PMC8388914 DOI: 10.3390/antiox10081201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/15/2021] [Accepted: 07/19/2021] [Indexed: 11/17/2022] Open
Abstract
In holothuroids, oocyte maturation is stopped in ovaries at the prophase I stage of meiosis. In natural conditions, the blockage is removed during the spawning by an unknown mechanism. When oocytes are isolated by dissection, the meiotic release can be successfully induced by a natural inducer, the REES (i.e., Rough Extract of Echinoid Spawn) that is used in aquaculture to obtain viable larvae in mass. A thioredoxin has recently been identified in the REES as the molecule responsible for holothuroid oocyte maturation. As a redox-active protein, thioredoxin is thought to reduce target proteins within the oocyte membrane and initiate an intracellular reaction cascade that leads to the unblocking of the oocyte meiosis. Our results allow us to understand additional steps in the intracellular reaction cascade induced by the action of thioredoxin on oocytes. Pharmacological agents known to have activating or inhibiting actions on oocyte maturation have been used (Forskolin, Isobutylmethylxanthine, Hypoxanthine, 6-dimethyaminopurine, Lavendustin, Genistein, Roscovitine, Cycloheximide). The effects of these agents were analysed on oocytes of the holothuroid Holothuria tubulosa incubated with or without REES and were compared to those obtained with another reducing agent, the dithiothreitol. Our results demonstrated that, at the opposite of dithiothreitol-induced oocyte maturation, thioredoxin-induced oocyte maturation is cAMP independent, but dependent of the presence of calcium in the seawater. Both pathways of induction require the activation of protein serine/threonine kinases.
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Affiliation(s)
- Jérôme Delroisse
- Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium;
- Belaza Marine Station, Institut Halieutique et des Sciences Marines, University of Toliaria, Toliaria 601, Madagascar
| | - Aline Léonet
- Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium;
- Haute Ecole Du Hainaut, 7000 Mons, Belgium
| | - Henri Alexandre
- Embryology Laboratory, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium;
| | - Igor Eeckhaut
- Biology of Marine Organisms and Biomimetics Unit, Research Institute for Biosciences, University of Mons, 7000 Mons, Belgium;
- Haute Ecole Du Hainaut, 7000 Mons, Belgium
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11
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Mita M, Osugi T, Matsubara S, Kawada T, Satake H, Katayama H. A relaxin-like gonad-stimulating peptide identified from the starfish Astropecten scoparius. Mol Reprod Dev 2020; 88:34-42. [PMID: 33244845 DOI: 10.1002/mrd.23444] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 11/12/2022]
Abstract
A relaxin-like gonad-stimulating peptide (RGP) in starfish was the first identified invertebrate gonadotropin responsible for final gamete maturation. An RGP ortholog was newly identified from Astropecten scoparius of the order Paxillosida. The A. scoparius RGP (AscRGP) precursor is encoded by a 354 base pair open reading frame and is a 118 amino acid (aa) protein consisting of a signal peptide (26 aa), B-chain (21 aa), C-peptide (47 aa), and A-chain (24 aa). There are three putative processing sites (Lys-Arg) between the B-chain and C-peptide, between the C-peptide and A-chain, and within the C-peptide. This structural organization revealed that the mature AscRGP is composed of A- and B-chains with two interchain disulfide bonds and one intrachain disulfide bond. The C-terminal residues of the B-chain are Gln-Gly-Arg, which is a potential substrate for formation of an amidated C-terminal Gln residue. Non-amidated (AscRGP-GR) and amidated (AscRGP-NH2 ) peptides were chemically synthesized and their effect on gamete shedding activity was examined using A. scoparius ovaries. Both AscRGP-GR and AscRGP-NH2 induced oocyte maturation and ovulation in similar dose-dependent manners. This is the first report on a C-terminally amidated functional RGP. Collectively, these results suggest that AscRGP-GR and AscRGP-NH2 act as a natural gonadotropic hormone in A. scoparius.
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Affiliation(s)
- Masatoshi Mita
- Department of Biochemistry, Showa University School of Medicine, Shinagawa-ku, Tokyo, Japan
| | - Tomohiro Osugi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Soraku-gun, Kyoto, Japan
| | - Shin Matsubara
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Soraku-gun, Kyoto, Japan
| | - Tsuyoshi Kawada
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Soraku-gun, Kyoto, Japan
| | - Honoo Satake
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Soraku-gun, Kyoto, Japan
| | - Hidekazu Katayama
- Department of Applied Biochemistry, Tokai University, Hiratsuka, Kanagawa, Japan
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12
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Mita M, Matsubara S, Osugi T, Shiraishi A, Wada A, Satake H. A novel G protein-coupled receptor for starfish gonadotropic hormone, relaxin-like gonad-stimulating peptide. PLoS One 2020; 15:e0242877. [PMID: 33226996 PMCID: PMC7682835 DOI: 10.1371/journal.pone.0242877] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 11/10/2020] [Indexed: 12/12/2022] Open
Abstract
Gonadotropic hormones play important regulatory roles in reproduction. Relaxin-like gonad-stimulating peptide (RGP) is a gonadotropin-like hormone in starfish. However, a receptor for RGP remains to be identified. Here, we describe the identification of an authentic receptor for RGP (RGPR) in the starfish, Patiria pectinifera. A binding assay using radioiodinated P. pectinifera RGP (PpeRGP) revealed that RGPR was expressed in ovarian follicle cells. A RGPR candidate was identified by homology-searching of transcriptome data of P. pectinifera follicle cells. Based on the contig sequences, a putative 947-amino acid PpeRGPR was cloned from follicle cells. Like the vertebrate relaxin family peptide receptors (RXFP 1 and 2), PpeRGPR was a G protein-coupled receptor that harbored a low-density lipoprotein-receptor class A motif and leucine-rich repeat sequences in the extracellular domain of the N-terminal region. Sf9 cells transfected with Gαq16-fused PpeRGPR activated calcium ion mobilization in response to PpeRGP, but not to RGP of another starfish Asterias amurensis, in a dose-dependent fashion. These results confirmed the species-specific reactivity of RGP and the cognate receptor. Thus, the present study provides evidence that PpeRGPR is a specific receptor for PpeRGP. To the best of our knowledge, this is the first report on the identification of a receptor for echinoderm RGP.
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Affiliation(s)
- Masatoshi Mita
- Department of Biochemistry, Showa University School of Medicine, Tokyo, Japan
| | - Shin Matsubara
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Tomohiro Osugi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Akira Shiraishi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Azumi Wada
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Honoo Satake
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
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Mita M, Osugi T, Takahashi T, Watanabe T, Satake H. Mechanism of gamete shedding in starfish: Involvement of acetylcholine in extracellular Ca 2+-dependent contraction of gonadal walls. Gen Comp Endocrinol 2020; 290:113401. [PMID: 31981689 DOI: 10.1016/j.ygcen.2020.113401] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 01/14/2020] [Accepted: 01/20/2020] [Indexed: 01/22/2023]
Abstract
Starfish are suitable animals for the study of hormonal regulatory mechanism of oocyte maturation and ovulation. Although contraction of the gonadal walls is essential for the shedding gametes, little was known about the mechanism. When ovaries of starfish Patiria pectinifera were incubated in Ca2+-free seawater in the presence of 1-methyladenine (1-MeAde), the germinal vesicles in oocytes broke down, but no ovulation occurred. Verapamil, a potent inhibitor of voltage-dependent Ca2+ channels, inhibited 1-MeAde-induced ovulation. These results suggest that extracellular Ca2+ and its influx are indispensable for gamete shedding. Furthermore, acetylcholine (ACh) was involved in extracellular Ca2+-dependent contractions of gonadal walls. Although 1-MeAde failed to induce contraction of the gonadal walls in normal seawater containing L-glutamic acid, application of ACh or carbachol, an agonist for ACh receptor, could bring about shedding of mature oocytes. Atropine, a competitive antagonist of the muscarinic ACh receptor, inhibited 1-MeAde-induced ovulation, but a nicotinic ACh receptor antagonist mecamylamine had no effect. Furthermore, ACh was detected in the ovaries and testes in P. pectinifera. These findings suggest that ACh acts on muscarinic ACh receptors in gonadal walls to induce peristaltic contractions caused by Ca2+ influx via Ca2+ channels in the gonadal wall muscle for gamete shedding. The present study also provides new insight into the regulatory mechanism that 1-MeAde acts on secretion of ACh in ovaries and testes.
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Affiliation(s)
- Masatoshi Mita
- Department of Biochemistry, Showa University School of Medicine, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan; Center for Advanced Biomedical Sciences, Research Institute for Science and Engineering, Waseda University, 2-2, Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
| | - Tomohiro Osugi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
| | - Toshio Takahashi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
| | - Takehiro Watanabe
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
| | - Honoo Satake
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, 8-1-1 Seikadai, Seika-cho, Soraku-gun, Kyoto 619-0284, Japan
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14
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Mita M, Elphick MR, Katayama H. Effect of chimeric relaxin-like gonad-stimulating peptides on oocyte maturation and ovulation in the starfish Asterias rubens and Aphelasterias japonica. Gen Comp Endocrinol 2020; 287:113351. [PMID: 31805285 DOI: 10.1016/j.ygcen.2019.113351] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/15/2019] [Accepted: 11/29/2019] [Indexed: 12/14/2022]
Abstract
A relaxin-like gonad-stimulating peptide (RGP), comprising two peptide chains (A- and B-chains) linked by two interchain bonds and one intrachain disulfide bond, acts as a gonadotropin in starfish. RGP orthologs have been identified in several starfish species, including Patiria pectinifera (PpeRGP), Asterias rubens (AruRGP) and Aphelasterias japonica (AjaRGP). To analyze species-specificity, this study examined the effects on oocyte maturation and ovulation in ovaries of A. rubens and A. japonica of nine RGP derivatives comprising different combinations of A- and B-chains from the three species. All nine RGP derivatives induced spawning in A. rubens and A. japonica ovaries. However, AruRGP, AjaRGP and their chimeric derivatives were more potent than peptides containing the A- or B-chain of PpeRGP. Three-dimensional models of the structures of the RGP derivatives revealed that residues in the B-chains, such as AspB6, MetB10 and PheB13 in PpeRGP and GluB7, MetB11, and TyrB14 in AruRGP and AjaRGP, respectively, are likely to be involved in receptor binding. Conversely, it is likely that ArgA18 in the A-chain of AruRGP and AjaRGP impairs binding of these peptides to the PpeRGP receptor in P. pectinifera. In conclusion, this study provides new insights into the structural basis of RGP bioactivity and RGP receptor activation in starfish.
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Affiliation(s)
- Masatoshi Mita
- Department of Biochemistry, Showa University School of Medicine, Hatanodai 8-5-1, Shinagawa-ku, Tokyo 142-8555, Japan; Center for Advanced Biomedical Sciences, Waseda University, 2-2, Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
| | - Maurice R Elphick
- Queen Mary University of London, School of Biological & Chemical Sciences, Mile End Road, London E1 4NS, UK
| | - Hidekazu Katayama
- Department of Applied Biochemistry, School of Engineering, Tokai University, 4-1-1, Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
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15
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Chieu HD, Suwansa-Ard S, Wang T, Elizur A, Cummins SF. Identification of neuropeptides in the sea cucumber Holothuria leucospilota. Gen Comp Endocrinol 2019; 283:113229. [PMID: 31348958 DOI: 10.1016/j.ygcen.2019.113229] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 07/17/2019] [Accepted: 07/22/2019] [Indexed: 12/17/2022]
Abstract
Neuropeptides play important roles in the regulation of physiological processes such as growth, metabolism and reproduction. In sea cucumbers (Phylum Echinodermata), numerous neuropeptides have been identified and some are attributed to reproductive processes. In this study, our goal was to gain a better understanding of the neuropeptide repertoire for the black sea cucumber Holothuria leucospilota, a species that has been severely overfished from the wild due to human consumption. We applied in silico transcriptome analysis of the adult H. leucospilota radial nerve cord, gonad and body wall to elucidate 35 neuropeptides that are conserved throughout the Bilateria. Then, liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis of radial nerve cord was employed and showed an additional 8 putative novel neuropeptide precursors, whose predicative cleaved peptides do not share sequence similarity with any reported neuropeptides. These data provide an important basis for experimental approaches to manipulate H. leucospilota broodstock reproduction and growth in culture, which will hopefully re-establish population numbers.
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Affiliation(s)
- Hoang Dinh Chieu
- Genecology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, Queensland 4556, Australia; Research Institute for Marine Fisheries (RIMF), 224 LeLai Street, HaiPhong City, Viet Nam
| | - Saowaros Suwansa-Ard
- Genecology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, Queensland 4556, Australia
| | - Tianfang Wang
- Genecology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, Queensland 4556, Australia
| | - Abigail Elizur
- Genecology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, Queensland 4556, Australia
| | - Scott F Cummins
- Genecology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, Queensland 4556, Australia.
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16
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Katayama H, Mizuno R, Mita M. A novel approach for preparing disulfide-rich peptide-KLH conjugate applicable to the antibody production. Biosci Biotechnol Biochem 2019; 83:1791-1799. [DOI: 10.1080/09168451.2019.1618696] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
ABSTRACT
To produce the antiserum against a small peptide, the target peptide-keyhole limpet hemocyanine (KLH) conjugate is generally used as an antigen, although the disulfide-rich peptide-KLH conjugate is still difficult to prepare. In our previous study, we have developed a preparation method of the disulfide-rich peptide-KLH conjugate, and this method was applied to produce the antiserum against a relaxin-like peptide. However, this method is limited to the synthetic peptide antigen, and is not applicable to a native or a recombinant peptide. In this study, to expand the applicability of this method to wide variety of peptides, we newly designed a novel thiol probe enabling the conjugation between various peptides and KLH, and applied it to produce the antiserum against relaxin-like peptide of a starfish Asterias amurensis. The antiserum obtained here showed high antibody-titer and good specificity, strongly suggesting that the method developed in this study is applicable to various peptides.
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Affiliation(s)
- Hidekazu Katayama
- Department of Applied Biochemistry, School of Engineering, Tokai University, Kanagawa, Japan
| | - Ryo Mizuno
- Department of Applied Biochemistry, School of Engineering, Tokai University, Kanagawa, Japan
| | - Masatoshi Mita
- Center for Advanced Biomedical Sciences, TWIns, Research Institute for Science and Engineering, Waseda University, Tokyo, Japan
- Department of Biochemistry, Showa University School of Medicine, Tokyo, Japan
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17
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Smith MK, Chieu HD, Aizen J, Mos B, Motti CA, Elizur A, Cummins SF. A Crown-of-Thorns Seastar recombinant relaxin-like gonad-stimulating peptide triggers oocyte maturation and ovulation. Gen Comp Endocrinol 2019; 281:41-48. [PMID: 31102581 DOI: 10.1016/j.ygcen.2019.05.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 05/04/2019] [Accepted: 05/14/2019] [Indexed: 12/31/2022]
Abstract
The Acanthaster planci species-complex [Crown-of-Thorns Seastar (COTS)] are highly fecund echinoderms that exhibit population outbreaks on coral reef ecosystems worldwide, including the Australian Great Barrier Reef. A better understanding of the COTS molecular biology is critical towards efforts in controlling outbreaks and assisting reef recovery. In seastars, the heterodimeric relaxin-like gonad stimulating peptide (RGP) is responsible for triggering a neuroendocrine cascade that regulates resumption of oocyte meiosis prior to spawning. Our comparative RNA-seq analysis indicates a general increase in RGP gene expression in the female radial nerve cord during the reproductive season. Also, the sensory tentacles demonstrate a significantly higher expression level than radial nerve cord. A recombinant COTS RGP, generated in a yeast expression system, is highly effective in inducing oocyte germinal vesicle breakdown (GVBD), followed by ovulation from ovarian fragments. The findings of this study provide a foundation for more in-depth molecular analysis of the reproductive neuroendocrine physiology of the COTS and the RGP.
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Affiliation(s)
- Meaghan K Smith
- GeneCology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, Queensland 4556, Australia
| | - Hoang Dinh Chieu
- GeneCology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, Queensland 4556, Australia
| | - Joseph Aizen
- The School of Marine Science, Ruppin Academic Centre, 4029700 Michmoret, Israel; GeneCology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, Queensland 4556, Australia
| | - Benjamin Mos
- National Marine Science Centre, Southern Cross University, 2 Bay Drive, Coffs Harbour, NSW 2450, Australia
| | - Cherie A Motti
- Australian Institute of Marine Science (AIMS), Cape Ferguson, Townsville, Queensland 4810, Australia
| | - Abigail Elizur
- GeneCology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, Queensland 4556, Australia
| | - Scott F Cummins
- GeneCology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, Queensland 4556, Australia.
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18
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Mita M, Nakamura K, Tsutsui K, Katayama H. Interaction of starfish gonadotropin with its receptor: Effect of chimeric relaxin-like gonad-stimulating peptides. Gen Comp Endocrinol 2019; 276:30-36. [PMID: 30796897 DOI: 10.1016/j.ygcen.2019.02.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 02/15/2019] [Accepted: 02/19/2019] [Indexed: 10/27/2022]
Abstract
A relaxin-like gonad-stimulating peptide (RGP) of starfish Patiria (Asterina) pectinifera is the first identified invertebrate gonadotropin for final gamete maturation. Recently, we found three orthologs of RGP in the class Asteroida; PpeRGP in P. pectinifera, AamRGP in Asterias amurensis, and AjaRGP in Aphelasterias japonica. In this study, nine kinds of RGP derivatives with exchanged each A- and B-chain were synthesized chemically to analyze the interaction of RGP with its receptor. Among these RGP derivatives, PpeRGP and its chimeric RGPs with B-chains from AamRGP or AjaRGP could induce oocyte maturation and ovulation in P. pectinifera ovaries. In contrast, other RGP derivatives were failed to induce spawning in P. pectinifera ovaries. Circular dichroism spectra of PpeRGP were similar to those of chimeric RGPs with the B-chains from AamRGP or AjaRGP. Furthermore, the predicted three-dimensional structure models of the B-chains from RGP derivatives have almost the same conformation. These findings suggest that the B-chain of PpeRGP is involved in binding to its receptor. Thus, it is likely that the A-chain of AamRGP or AjaRGP disturbs the binding of the PpeRGP B-chain to its receptor.
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Affiliation(s)
- Masatoshi Mita
- Center for Advanced Biomedical Sciences, Research Institute for Science and Engineering, Waseda University, 2-2, Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
| | - Keitaro Nakamura
- Department of Applied Biochemistry, School of Engineering, Tokai University, 4-1-1, Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
| | - Kazuyoshi Tsutsui
- Center for Advanced Biomedical Sciences, Research Institute for Science and Engineering, Waseda University, 2-2, Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan; Laboratory of Integrative Brain Sciences, Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, Wakamatsucho 2-2, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hidekazu Katayama
- Department of Applied Biochemistry, School of Engineering, Tokai University, 4-1-1, Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
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19
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Mita M. Starfish Gonadotropic Hormone: From Gamete-Shedding Substance to Relaxin-Like Gonad-Stimulating Peptide. Front Endocrinol (Lausanne) 2019; 10:182. [PMID: 30967842 PMCID: PMC6442644 DOI: 10.3389/fendo.2019.00182] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 03/04/2019] [Indexed: 12/02/2022] Open
Abstract
The first report of a gonadotropic substance in an invertebrate hot-water extract of radial nerve cords from starfish Asterias forbesi that induced the shedding of gametes when injected into the coelomic cavity in a ripe individual occurred in 1959. The active substance was named gamete-shedding substance (GSS) or radial nerve factor. GSS is the primary mediator of oocyte maturation and ovulation in starfish. However, the effect of GSS is indirect. Resumption of meiosis in immature oocytes and release from the ovary are induced by a second mediator, maturation-inducing hormone, identified as 1-methyladenine (1-MeAde) in starfish. The role of GSS is to induce 1-MeAde production by ovarian follicle cells. Thus, GSS was redesignated as gonad-stimulating substance (also GSS). Although GSS has been characterized biochemically as a peptide hormone, identification of the chemical structure had to wait until 2009. Fifty years after the initial finding, GSS was purified from the radial nerve cords of starfish Patiria pectinifera (P. pectinifera). The purified hormone was a heterodimer composed of A- and B-chains, with disulfide cross-linkages. Based on its cysteine motif, GSS is classified as a member of the insulin/insulin-like growth factor (IGF)/relaxin superfamily. More specifically, phylogenetic sequence analysis revealed that P. pectinifera GSS is a member of the relaxin-type peptide family. Therefore, GSS in starfish has been redesignated as relaxin-like gonad-stimulating peptide (RGP). Subsequently, orthologs of P. pectinifera RGP have been identified in other starfish species, including Asterias amurensis (A. amurensis), and Aphelasterias japonica (A. japonica).
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Affiliation(s)
- Masatoshi Mita
- Center for Advanced Biomedical Sciences, Research Institute for Science and Engineering, Waseda University, Tokyo, Japan
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20
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Chieu HD, Turner L, Smith MK, Wang T, Nocillado J, Palma P, Suwansa-Ard S, Elizur A, Cummins SF. Aquaculture Breeding Enhancement: Maturation and Spawning in Sea Cucumbers Using a Recombinant Relaxin-Like Gonad-Stimulating Peptide. Front Genet 2019; 10:77. [PMID: 30838021 PMCID: PMC6389678 DOI: 10.3389/fgene.2019.00077] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/28/2019] [Indexed: 12/22/2022] Open
Abstract
Wild sea cucumber resources have been rapidly exhausted and therefore there is an urgent need to develop approaches that will help restocking. Currently, there is a lack of information regarding the genes involved in sea cucumber reproductive processes. The neurohormone relaxin-like gonad-stimulating peptide (RGP) has been identified as the active gonad-stimulating peptide in sea stars (Asteroidea), which could also be present in other echinoderm groups. In this study, a sea cucumber RGP was identified and confirmed by phylogenetic analysis. A recombinant Holothuria scabra RGP was produced in the yeast Pichia pastoris and confirmed by mass spectrometry. To assess bioactivity, four levels of purification were tested in an in vitro germinal vesicle breakdown (GVBD) bioassay. The most pure form induced 98.56 ± 1.19% GVBD in H. scabra and 89.57 ± 1.19% GVBD in Holothuria leucospilota. Cruder levels of purification still resulted in some GVBD. Upon single injection into female H. scabra, the recombinant RGP induced head waving behavior followed by spawning within 90–170 min. Spawned oocytes were fertilized successfully, larvae settled and developed into juveniles. Our results provide a key finding for the development of a break-through new artificial breeding approach in sea cucumber aquaculture.
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Affiliation(s)
- Hoang Dinh Chieu
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia.,Research Institute for Marine Fisheries, HaiPhong, Vietnam
| | - Luke Turner
- Tasmanian Seafoods Pty. Ltd., Smithton, TAS, Australia
| | - Meaghan K Smith
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Tianfang Wang
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Josephine Nocillado
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Peter Palma
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia.,Aquaculture Department, Southeast Asian Fisheries Development Center, Iloilo, Philippines
| | - Saowaros Suwansa-Ard
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Abigail Elizur
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Scott F Cummins
- Genecology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia
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21
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Mita M, Katayama H. Enzyme-linked immunosorbent assay of relaxin-like gonad-stimulating peptide in the starfish Patiria (Asterina) pectinifera. Gen Comp Endocrinol 2018; 258:157-162. [PMID: 28859971 DOI: 10.1016/j.ygcen.2017.08.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 08/25/2017] [Accepted: 08/27/2017] [Indexed: 10/19/2022]
Abstract
A relaxin-like gonad-stimulating peptide (RGP) from starfish Patiria (Asterina) pectinifera is the first identified invertebrate gonadotropin for final gamete maturation. Recently, we succeeded in obtaining specific antibodies against P. pectinifera RGP (PpeRGP). In this study, the antibodies were used for the development of a specific and sensitive enzyme-linked immunosorbent assay (ELISA) for the measurement of PpeRGP. A biotin-conjugated peptide that binds to peroxidase-conjugated streptavidin is specifically detectable using 3,3',5,5'-tetramethylbenzidine (TMB)/hydrogen peroxide as a substrate; therefore, biotin-conjugated RGP (biotin-PpeRGP) was synthesized chemically. Similarly to PpeRGP, synthetic biotin-PpeRGP bound to the antibody against PpeRGP. In binding experiments with biotin-PpeRGP using wells coated with the antibody, a displacement curve was obtained using serial concentrations of PpeRGP. The ELISA system showed that PpeRGP could be measured in the range 0.01-10pmol per 50µl assay buffer. On the contrary, the B-chains of PpeRGP, Asterias amurensis RGP, Aphelasterias japonica RGP, and human relaxin showed minimal cross-reactivity in the ELISA, except that the A-chain of PpeRGP affected it slightly. These results strongly suggest that this ELISA system is highly specific and sensitive with respect to PpeRGP.
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Affiliation(s)
- Masatoshi Mita
- Department of Biology, Faculty of Education, Tokyo Gakugei University, Koganei-shi, Tokyo 184-8501, Japan.
| | - Hidekazu Katayama
- Department of Applied Biochemistry, School of Engineering, Tokai University, Kitakaname 4-1-1, Hiratsuka, Kanagawa 259-1292, Japan
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22
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Yamamoto K, Kiyomoto M, Katayama H, Mita M. Radioimmunoassay of relaxin-like gonad-stimulating peptide in the starfish Patiria (=Asterina) pectinifera. Gen Comp Endocrinol 2017; 243:84-88. [PMID: 27838378 DOI: 10.1016/j.ygcen.2016.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 11/05/2016] [Accepted: 11/08/2016] [Indexed: 10/20/2022]
Abstract
A relaxin-like gonad-stimulating peptide (RGP) from starfish Patiria (=Asterina) pectinifera is the first identified invertebrate gonadotropin for final gamete maturation. An antiserum against P. pectinifera RGP (PpeRGP) was produced by immunizing rabbits with a PpeRGP sulfanyl-polyethylene glycol derivative conjugated with keyhole limpet hemocyanin (KLH) as the antigen. The antiserum was used for the development of a specific and sensitive radioimmunoassay (RIA) for the measurement of RGP. In binding experiments using radioiodinated PpeRGP and antiserum against PpeRGP, a displacement curve was obtained using radioinert PpeRGP. The sensitivity of the RIA, defined as the amount of PpeRGP that significantly decreased the counts by 2 SD from the 100% bound point, averaged 0.040±0.002pmol PpeRGP per 100μl assay buffer (0.40±0.02nM) in 10 assays. Intra-assay and inter-assay coefficients of variation were 6.1% and 2.7%, respectively. Serial dilution of whole homogenates from the radial nerve cords and circumoral nerve-rings of P. pectinifera produced displacement curves parallel to the PpeRGP standard. Thus, the amounts of PpeRGP were determined as 1.54±0.09pmol/mg wet weight of radial nerves and 0.87±0.04pmol/mg wet weight of nerve-rings, respectively. On contrary, pyloric stomach, pyloric caeca, tube-feet, ovaries, testes, and ovarian follicle cells did not react in the RIA system. Furthermore, the A- and B-chains of PpeRGP, Asterias amurensis RGP, bovine insulin, and human relaxin did not show cross-reactivity in the RIA. These results strongly suggest that the RIA system is a highly specific and sensitive with respect to PpeRGP.
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Affiliation(s)
- Kazutoshi Yamamoto
- Department of Biology, Faculty of Education and Integrated Sciences, Center for Advanced Biomedical Sciences, Waseda University, Wakamatsucho 2-2, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Masato Kiyomoto
- Tateyama Marine Laboratory, Marine and Coastal Research Center, Ochanomizu University, Kou-yatsu 11, Tateyama, Chiba 294-0301, Japan
| | - Hidekazu Katayama
- Department of Applied Biochemistry, School of Engineering, Tokai University, Kitakaname 4-1-1, Hiratsuka, Kanagawa 259-1292, Japan
| | - Masatoshi Mita
- Department of Biology, Faculty of Education, Tokyo Gakugei University, Nukuikita-machi 4-1-1, Koganei-shi, Tokyo 184-8501, Japan.
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23
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Mita M. Inhibitory mechanism of l
-glutamic acid on spawning of the starfish Patiria
(Asterina
) pectinifera. Mol Reprod Dev 2017; 84:246-256. [DOI: 10.1002/mrd.22769] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/17/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Masatoshi Mita
- Department of Biology; Faculty of Education; Tokyo Gakugei University; Koganei Tokyo Japan
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Tian S, Egertová M, Elphick MR. Functional Characterization of Paralogous Gonadotropin-Releasing Hormone-Type and Corazonin-Type Neuropeptides in an Echinoderm. Front Endocrinol (Lausanne) 2017; 8:259. [PMID: 29033898 PMCID: PMC5626854 DOI: 10.3389/fendo.2017.00259] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 09/20/2017] [Indexed: 12/12/2022] Open
Abstract
Homologs of the vertebrate neuropeptide gonadotropin-releasing hormone (GnRH) have been identified in invertebrates, including the insect neuropeptide corazonin (CRZ). Recently, we reported the discovery of GnRH-type and CRZ-type signaling systems in an echinoderm, the starfish Asterias rubens, demonstrating that the evolutionary origin of paralogous GnRH-type and CRZ-type neuropeptides can be traced back to the common ancestor of protostomes and deuterostomes. Here, we have investigated the physiological roles of the GnRH-type (ArGnRH) and the CRZ-type (ArCRZ) neuropeptides in A. rubens, using mRNA in situ hybridization, immunohistochemistry and in vitro pharmacology. ArGnRH precursor (ArGnRHP)-expressing cells and ArGnRH-immunoreactive cells and/or processes are present in the radial nerve cords, circumoral nerve ring, digestive system (e.g., cardiac stomach and pyloric stomach), body wall-associated muscle (apical muscle), and appendages (tube feet, terminal tentacle). The general distribution of ArCRZ precursor (ArCRZP)-expressing cells is similar to that of ArGnRHP, but with specific local differences. For example, cells expressing ArGnRHP are present in both the ectoneural and hyponeural regions of the radial nerve cords and circumoral nerve ring, whereas cells expressing ArCRZP were only observed in the ectoneural region. In vitro pharmacological experiments revealed that both ArGnRH and ArCRZ cause contraction of cardiac stomach, apical muscle, and tube foot preparations. However, ArGnRH was more potent/effective than ArCRZ as a contractant of the cardiac stomach, whereas ArCRZ was more potent/effective than ArGnRH as a contractant of the apical muscle. These findings demonstrate that both ArGnRH and ArCRZ are myoexcitatory neuropeptides in starfish, but differences in their expression patterns and pharmacological activities are indicative of distinct physiological roles. This is the first study to investigate the physiological roles of both GnRH-type and CRZ-type neuropeptides in a deuterostome, providing new insights into the evolution and comparative physiology of these paralogous neuropeptide signaling systems in the Bilateria.
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Affiliation(s)
- Shi Tian
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Michaela Egertová
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Maurice R. Elphick
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
- *Correspondence: Maurice R. Elphick,
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