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Lone JB, Long JZ, Svensson KJ. Size matters: the biochemical logic of ligand type in endocrine crosstalk. LIFE METABOLISM 2024; 3:load048. [PMID: 38425548 PMCID: PMC10904031 DOI: 10.1093/lifemeta/load048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
The endocrine system is a fundamental type of long-range cell-cell communication that is important for maintaining metabolism, physiology, and other aspects of organismal homeostasis. Endocrine signaling is mediated by diverse blood-borne ligands, also called hormones, including metabolites, lipids, steroids, peptides, and proteins. The size and structure of these hormones are fine-tuned to make them bioactive, responsive, and adaptable to meet the demands of changing environments. Why has nature selected such diverse ligand types to mediate communication in the endocrine system? What is the chemical, signaling, or physiologic logic of these ligands? What fundamental principles from our knowledge of endocrine communication can be applied as we continue as a field to uncover additional new circulating molecules that are claimed to mediate long-range cell and tissue crosstalk? This review provides a framework based on the biochemical logic behind this crosstalk with respect to their chemistry, temporal regulation in physiology, specificity, signaling actions, and evolutionary development.
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Affiliation(s)
- Jameel Barkat Lone
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jonathan Z. Long
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, CA 94305, USA
- Sarafan ChEM-H, Stanford University, Stanford, CA 94305, USA
- Wu Tsai Human Performance Alliance, Stanford University, Stanford, CA 94305, USA
| | - Katrin J. Svensson
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, CA 94305, USA
- Sarafan ChEM-H, Stanford University, Stanford, CA 94305, USA
- Wu Tsai Human Performance Alliance, Stanford University, Stanford, CA 94305, USA
- Stanford Cardiovascular Institute, Stanford University School of Medicine, CA 94305, USA
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Tapia F, Peñaloza V, Silva-Olivares F, Sotomayor-Zárate R, Schmachtenberg O, Vielma AH. Glucagon Increases Retinal Rod Bipolar Cell Inhibition Through a D1 Dopamine Receptor-Dependent Pathway That Is Altered After Lens-Defocus Treatment in Mice. Invest Ophthalmol Vis Sci 2024; 65:46. [PMID: 38289613 PMCID: PMC10840015 DOI: 10.1167/iovs.65.1.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 01/05/2024] [Indexed: 02/01/2024] Open
Abstract
Purpose Members of the secretin/glucagon family have diverse roles in retinal physiological and pathological conditions. Out of them, glucagon has been associated with eye growth regulation and image defocus signaling in the eye, both processes central in myopia induction. On the other hand, dopamine is perhaps the most studied molecule in myopia and has been proposed as fundamental in myopia pathogenesis. However, glucagonergic activity in the mammalian retina and its possible link with dopaminergic signaling remain unknown. Methods To corroborate whether glucagon and dopamine participate together in the modulation of synaptic activity in the retina, inhibitory post-synaptic currents were measured in rod bipolar cells from retinal slices of wild type and negative lens-exposed mice, using whole cell patch-clamp recordings and selective pharmacology. Results Glucagon produced an increase of inhibitory post-synaptic current frequency in rod bipolar cells, which was also dependent on dopaminergic activity, as it was abolished by dopamine type 1 receptor antagonism and under scotopic conditions. The effect was also abolished after 3-week negative lens-exposure but could be recovered using dopamine type 1 receptor agonism. Conclusions Altogether, these results support a possible neuromodulatory role of glucagon in the retina of mammals as part of a dopaminergic activity-dependent synaptic pathway that is affected under myopia-inducing conditions.
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Affiliation(s)
- Felipe Tapia
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Universidad de Valparaíso, Valparaíso, Chile
- Programa de Doctorado en Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Valentín Peñaloza
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Universidad de Valparaíso, Valparaíso, Chile
| | - Francisco Silva-Olivares
- Laboratorio de Neuroquímica y Neurofarmacología, Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Universidad de Valparaíso, Valparaíso, Chile
| | - Ramón Sotomayor-Zárate
- Laboratorio de Neuroquímica y Neurofarmacología, Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Universidad de Valparaíso, Valparaíso, Chile
| | - Oliver Schmachtenberg
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Universidad de Valparaíso, Valparaíso, Chile
- Instituto de Biología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Alex H. Vielma
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Universidad de Valparaíso, Valparaíso, Chile
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Andrews PLR, Ponte G, Rosas C. Methodological considerations in studying digestive system physiology in octopus: limitations, lacunae and lessons learnt. Front Physiol 2022; 13:928013. [PMID: 36160859 PMCID: PMC9501996 DOI: 10.3389/fphys.2022.928013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
Current understanding of cephalopod digestive tract physiology is based on relatively “old” literature and a “mosaic of data” from multiple species. To provide a background to the discussion of methodologies for investigating physiology we first review the anatomy of the cephalopod digestive tract with a focus on Octopus vulgaris, highlighting structure-function relationships and species differences with potential functional consequences (e.g., absence of a crop in cuttlefish and squid; presence of a caecal sac in squid). We caution about extrapolation of data on the digestive system physiology from one cephalopod species to another because of the anatomical differences. The contribution of anatomical and histological techniques (e.g., digestive enzyme histochemistry and neurotransmitter immunohistochemistry) to understanding physiological processes is discussed. For each major digestive tract function we briefly review current knowledge, and then discuss techniques and their limitations for the following parameters: 1) Measuring motility in vitro (e.g., spatiotemporal mapping, tension and pressure), in vivo (labelled food, high resolution ultrasound) and aspects of pharmacology; 2) Measuring food ingestion and the time course of digestion with an emphasis on understanding enzyme function in each gut region with respect to time; 3) Assessing transepithelial transport of nutrients; 4) Measuring the energetic cost of food processing, impact of environmental temperature and metabolic rate (flow-through/intermittent respirometry); 4) Investigating neural (brain, gastric ganglion, enteric) and endocrine control processes with an emphasis on application of molecular techniques to identify receptors and their ligands. A number of major knowledge lacunae are identified where available techniques need to be applied to cephalopods, these include: 1) What is the physiological function of the caecal leaflets and intestinal typhlosoles in octopus? 2) What role does the transepithelial transport in the caecum and intestine play in ion, water and nutrient transport? 3) What information is signalled from the digestive tract to the brain regarding the food ingested and the progress of digestion? It is hoped that by combining discussion of the physiology of the cephalopod digestive system with an overview of techniques and identification of key knowledge gaps that this will encourage a more systematic approach to research in this area.
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Affiliation(s)
- Paul L. R. Andrews
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy
- *Correspondence: Paul L. R. Andrews,
| | - Giovanna Ponte
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy
| | - Carlos Rosas
- Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias, Universidad Nacional Autónoma de México, Sisal, Yucatán, Mexico
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Liu B, Lee G, Wu J, Deming J, Kuei C, Harrington A, Wang L, Towne J, Lovenberg T, Liu C, Sun S. The PAR2 signal peptide prevents premature receptor cleavage and activation. PLoS One 2020; 15:e0222685. [PMID: 32078628 PMCID: PMC7032737 DOI: 10.1371/journal.pone.0222685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 02/03/2020] [Indexed: 11/19/2022] Open
Abstract
Unlike closely related GPCRs, protease-activated receptors (PAR1, PAR2, PAR3, and PAR4) have a predicted signal peptide at their N-terminus, which is encoded by a separate exon, suggesting that the signal peptides of PARs may serve an important and unique function, specific for PARs. In this report, we show that the PAR2 signal peptide, when fused to the N-terminus of IgG-Fc, effectively induced IgG-Fc secretion into culture medium, thus behaving like a classical signal peptide. The presence of PAR2 signal peptide has a strong effect on PAR2 cell surface expression, as deletion of the signal peptide (PAR2ΔSP) led to dramatic reduction of the cell surface expression and decreased responses to trypsin or the synthetic peptide ligand (SLIGKV). However, further deletion of the tethered ligand region (SLIGKV) at the N-terminus rescued the cell surface receptor expression and the response to the synthetic peptide ligand, suggesting that the signal peptide of PAR2 may be involved in preventing PAR2 from intracellular protease activation before reaching the cell surface. Supporting this hypothesis, an Arg36Ala mutation on PAR2ΔSP, which disabled the trypsin activation site, increased the receptor cell surface expression and the response to ligand stimulation. Similar effects were observed when PAR2ΔSP expressing cells were treated with protease inhibitors. Our findings indicated that there is a role of the PAR2 signal peptide in preventing the premature activation of PAR2 from intracellular protease cleavage before reaching the cells surface. The same mechanism may also apply to PAR1, PAR3, and PAR4.
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Affiliation(s)
- Belinda Liu
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Grace Lee
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Jiejun Wu
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Janise Deming
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Chester Kuei
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Anthony Harrington
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Lien Wang
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Jennifer Towne
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Timothy Lovenberg
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Changlu Liu
- Janssen Research & Development, LLC, San Diego, California, United States of America
| | - Siquan Sun
- Janssen Research & Development, LLC, San Diego, California, United States of America
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Identification of a conformational heparin-recognition motif on the peptide hormone secretin: key role for cell surface binding. Biochem J 2017; 474:2249-2260. [PMID: 28536157 DOI: 10.1042/bcj20170035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 04/30/2017] [Accepted: 05/23/2017] [Indexed: 11/17/2022]
Abstract
Secretin is a peptide hormone that exerts pleiotropic physiological functions by specifically binding to its cognate membrane-bound receptor. The membrane catalysis model of peptide-receptor interactions states that soluble peptidic ligands initially interact with the plasma membrane. This interaction increases the local concentration and structures the peptide, enhancing the rate of receptor binding. However, this model does not consider the dense network of glycosaminoglycans (GAGs) at the surface of eukaryotic cells. These sulfated polysaccharide chains are known to sequester numerous proteic signaling molecules. In the present study, we evaluated the interaction between the peptide hormone secretin and sulfated GAGs and its contribution to cell surface binding. Using GAG-deficient cells and competition experiments with soluble GAGs, we observed by confocal microscopy and flow cytometry that GAGs mediate the sequestration of secretin at the cell surface. Isothermal titration calorimetry and surface plasmon resonance revealed that secretin binds to heparin with dissociation constants ranging between 0.9 and 4 μM. By designing secretin derivatives with a restricted conformational ensemble, we observed that this interaction is mediated by the presence of a specific conformational GAG-recognition motif that decorates the surface of the peptide upon helical folding. The present study identifies secretin as a novel GAG-binding polypeptide and opens new research direction on the functional role of GAGs in the biology of secretin.
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Hu CK, Southey BR, Romanova EV, Maruska KP, Sweedler JV, Fernald RD. Identification of prohormones and pituitary neuropeptides in the African cichlid, Astatotilapia burtoni. BMC Genomics 2016; 17:660. [PMID: 27543050 PMCID: PMC4992253 DOI: 10.1186/s12864-016-2914-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 07/06/2016] [Indexed: 12/14/2022] Open
Abstract
Background Cichlid fishes have evolved remarkably diverse reproductive, social, and feeding behaviors. Cell-to-cell signaling molecules, notably neuropeptides and peptide hormones, are known to regulate these behaviors across vertebrates. This class of signaling molecules derives from prohormone genes that have undergone multiple duplications and losses in fishes. Whether and how subfunctionalization, neofunctionalization, or losses of neuropeptides and peptide hormones have contributed to fish behavioral diversity is largely unknown. Information on fish prohormones has been limited and is complicated by the whole genome duplication of the teleost ancestor. We combined bioinformatics, mass spectrometry-enabled peptidomics, and molecular techniques to identify the suite of neuropeptide prohormones and pituitary peptide products in Astatotilapia burtoni, a well-studied member of the diverse African cichlid clade. Results Utilizing the A. burtoni genome, we identified 148 prohormone genes, with 21 identified as a single copy and 39 with at least 2 duplicated copies. Retention of prohormone duplicates was therefore 41 %, which is markedly above previous reports for the genome-wide average in teleosts. Beyond the expected whole genome duplication, differences between cichlids and mammals can be attributed to gene loss in tetrapods and additional duplication after divergence. Mass spectrometric analysis of the pituitary identified 620 unique peptide sequences that were matched to 120 unique proteins. Finally, we used in situ hybridization to localize the expression of galanin, a prohormone with exceptional sequence divergence in cichlids, as well as the expression of a proopiomelanocortin, prohormone that has undergone an additional duplication in some bony fish lineages. Conclusion We characterized the A. burtoni prohormone complement. Two thirds of prohormone families contain duplications either from the teleost whole genome duplication or a more recent duplication. Our bioinformatic and mass spectrometric findings provide information on a major vertebrate clade that will further our understanding of the functional ramifications of these prohormone losses, duplications, and sequence changes across vertebrate evolution. In the context of the cichlid radiation, these findings will also facilitate the exploration of neuropeptide and peptide hormone function in behavioral diversity both within A. burtoni and across cichlid and other fish species. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2914-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Caroline K Hu
- Department of Biology, Stanford University, Stanford, CA, 94305, USA.,Present address: Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Bruce R Southey
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Elena V Romanova
- Department of Chemistry and the Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Karen P Maruska
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Jonathan V Sweedler
- Department of Chemistry and the Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Russell D Fernald
- Department of Biology, Stanford University, Stanford, CA, 94305, USA.
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Affiliation(s)
- Hubert Vaudry
- INSERM U982International Associated Laboratory Samuel de Champlain, PRIMACEN, IRIB, University of Rouen, 76821 Mont-Saint-Aignan, France
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