Mysterious inhibitory cell regulator investigated and found likely to be secretogranin II related
In the context of a hunt for a postulated hormone that is tissue-mass inhibiting and reproductively associated, there is described probable relatedness to a granin protein. A 7–8 kDa polypeptide candidate (gels/MS) appeared in a bioassay-guided fractionation campaign involving sheep plasma. An N-ter...
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PeerJ Inc.
2017-10-01
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| Online Access: | https://peerj.com/articles/3833.pdf |
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| author | John E. Hart Iain J. Clarke Gail P. Risbridger Ben Ferneyhough Mónica Vega-Hernández |
| author_facet | John E. Hart Iain J. Clarke Gail P. Risbridger Ben Ferneyhough Mónica Vega-Hernández |
| author_sort | John E. Hart |
| collection | DOAJ |
| description | In the context of a hunt for a postulated hormone that is tissue-mass inhibiting and reproductively associated, there is described probable relatedness to a granin protein. A 7–8 kDa polypeptide candidate (gels/MS) appeared in a bioassay-guided fractionation campaign involving sheep plasma. An N-terminal sequence of 14 amino acids was obtained for the polypeptide by Edman degradation. Bioinformatics and molecular biology failed to illuminate any ovine or non-ovine protein which might relate to this sequence. The N-terminal sequence was synthesized as the 14mer EPL001 peptide and surprisingly found to be inhibitory in an assay in vivo of compensatory renal growth in the rat and modulatory of nematode fecundity, in line with the inhibitory hormone hypothesis. Antibodies were raised to EPL001 and their deployment upheld the hypothesis that the EPL001 amino acid sequence is meaningful and relevant, notwithstanding bioinformatic obscurity. Immunohistochemistry (IHC) in sheep, rodents and humans yielded staining of seeming endocrine relevance (e.g. hypothalamus, gonads and neuroendocrine cells in diverse tissues), with apparent upregulation in certain human tumours (e.g. pheochromocytoma). Discrete IHC staining in Drosophila melanogaster embryo brain was seen in glia and in neuroendocrine cells, with staining likely in the corpus cardiacum. The search for the endogenous antigen involved immunoprecipitation (IP) followed by liquid chromatography and mass spectrometry (LC–MS). Feedstocks were PC12 conditioned medium and aqueous extract of rat hypothalamus—both of which had anti-proliferative and pro-apoptotic effects in an assay in vitro involving rat bone marrow cells, which inhibition was subject to prior immunodepletion with an anti-EPL001 antibody—together with fruit fly embryo material. It is concluded that the mammalian antigen is likely secretogranin II (SgII) related. The originally seen 7–8 kDa polypeptide is suggested to be a new proteoform of secretogranin II of ∼70 residues, SgII-70, with the anti-EPL001 antibody seeing a discontinuous epitope. The fly antigen is probably Q9W2X8 (UniProt), an uncharacterised protein newly disclosed as a granin and provisionally dubbed macrogranin I (MgI). SgII and Q9W2X8 merit further investigation in the context of tissue-mass inhibition. |
| first_indexed | 2024-03-09T06:25:48Z |
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| institution | Directory Open Access Journal |
| issn | 2167-8359 |
| language | English |
| last_indexed | 2024-03-09T06:25:48Z |
| publishDate | 2017-10-01 |
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| spelling | doaj.art-50a27b09d295433b9e9a3d87036268162023-12-03T11:20:42ZengPeerJ Inc.PeerJ2167-83592017-10-015e383310.7717/peerj.3833Mysterious inhibitory cell regulator investigated and found likely to be secretogranin II relatedJohn E. Hart0Iain J. Clarke1Gail P. Risbridger2Ben Ferneyhough3Mónica Vega-Hernández4Endocrine Pharmaceuticals, Tadley, Hampshire, UKDepartment of Physiology, Neuroscience Program, Monash Biomedical Discovery Institute, Monash University, Clayton, VIC, AustraliaDepartment of Anatomy and Developmental Biology, Biomedical Discovery Institute, Monash University, Clayton, VIC, AustraliaSystems Biology Laboratory UK, Abingdon, Oxfordshire, UKDepartment of Zoology, Lawrence Laboratory, University of Cambridge, Cambridge, Cambridgeshire, UKIn the context of a hunt for a postulated hormone that is tissue-mass inhibiting and reproductively associated, there is described probable relatedness to a granin protein. A 7–8 kDa polypeptide candidate (gels/MS) appeared in a bioassay-guided fractionation campaign involving sheep plasma. An N-terminal sequence of 14 amino acids was obtained for the polypeptide by Edman degradation. Bioinformatics and molecular biology failed to illuminate any ovine or non-ovine protein which might relate to this sequence. The N-terminal sequence was synthesized as the 14mer EPL001 peptide and surprisingly found to be inhibitory in an assay in vivo of compensatory renal growth in the rat and modulatory of nematode fecundity, in line with the inhibitory hormone hypothesis. Antibodies were raised to EPL001 and their deployment upheld the hypothesis that the EPL001 amino acid sequence is meaningful and relevant, notwithstanding bioinformatic obscurity. Immunohistochemistry (IHC) in sheep, rodents and humans yielded staining of seeming endocrine relevance (e.g. hypothalamus, gonads and neuroendocrine cells in diverse tissues), with apparent upregulation in certain human tumours (e.g. pheochromocytoma). Discrete IHC staining in Drosophila melanogaster embryo brain was seen in glia and in neuroendocrine cells, with staining likely in the corpus cardiacum. The search for the endogenous antigen involved immunoprecipitation (IP) followed by liquid chromatography and mass spectrometry (LC–MS). Feedstocks were PC12 conditioned medium and aqueous extract of rat hypothalamus—both of which had anti-proliferative and pro-apoptotic effects in an assay in vitro involving rat bone marrow cells, which inhibition was subject to prior immunodepletion with an anti-EPL001 antibody—together with fruit fly embryo material. It is concluded that the mammalian antigen is likely secretogranin II (SgII) related. The originally seen 7–8 kDa polypeptide is suggested to be a new proteoform of secretogranin II of ∼70 residues, SgII-70, with the anti-EPL001 antibody seeing a discontinuous epitope. The fly antigen is probably Q9W2X8 (UniProt), an uncharacterised protein newly disclosed as a granin and provisionally dubbed macrogranin I (MgI). SgII and Q9W2X8 merit further investigation in the context of tissue-mass inhibition.https://peerj.com/articles/3833.pdfHormoneTissue reductionHypothalamusGraninFruit flyQ9W2X8 |
| spellingShingle | John E. Hart Iain J. Clarke Gail P. Risbridger Ben Ferneyhough Mónica Vega-Hernández Mysterious inhibitory cell regulator investigated and found likely to be secretogranin II related PeerJ Hormone Tissue reduction Hypothalamus Granin Fruit fly Q9W2X8 |
| title | Mysterious inhibitory cell regulator investigated and found likely to be secretogranin II related |
| title_full | Mysterious inhibitory cell regulator investigated and found likely to be secretogranin II related |
| title_fullStr | Mysterious inhibitory cell regulator investigated and found likely to be secretogranin II related |
| title_full_unstemmed | Mysterious inhibitory cell regulator investigated and found likely to be secretogranin II related |
| title_short | Mysterious inhibitory cell regulator investigated and found likely to be secretogranin II related |
| title_sort | mysterious inhibitory cell regulator investigated and found likely to be secretogranin ii related |
| topic | Hormone Tissue reduction Hypothalamus Granin Fruit fly Q9W2X8 |
| url | https://peerj.com/articles/3833.pdf |
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