1
|
Huang AY, Taylor AMW, Ghogha A, Pribadi M, Wang Q, Kim TSJ, Cahill CM, Coppola G, Evans CJ. Genetic and functional analysis of a Pacific hagfish opioid system. J Neurosci Res 2020; 100:19-34. [PMID: 32830380 DOI: 10.1002/jnr.24682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/22/2020] [Accepted: 06/08/2020] [Indexed: 12/12/2022]
Abstract
The actions of endogenous opioids and nociceptin/orphanin FQ are mediated by four homologous G protein-coupled receptors that constitute the opioid receptor family. However, little is known about opioid systems in cyclostomes (living jawless fish) and how opioid systems might have evolved from invertebrates. Here, we leveraged de novo transcriptome and low-coverage whole-genome assembly in the Pacific hagfish (Eptatretus stoutii) to identify and characterize the first full-length coding sequence for a functional opioid receptor in a cyclostome. Additionally, we define two novel endogenous opioid precursors in this species that predict several novel opioid peptides. Bioinformatic analysis shows no closely related opioid receptor genes in invertebrates with regard either to the genomic organization or to conserved opioid receptor-specific sequences that are common in all vertebrates. Furthermore, no proteins analogous to vertebrate opioid precursors could be identified by genomic searches despite previous claims of protein or RNA-derived sequences in several invertebrate species. The presence of an expressed orthologous receptor and opioid precursors in the Pacific hagfish confirms that a functional opioid system was likely present in the common ancestor of all extant vertebrates some 550 million years ago, earlier than all previous authenticated accounts. We discuss the premise that the cyclostome and vertebrate opioid systems evolved from invertebrate systems concerned with antimicrobial defense and speculate that the high concentrations of opioid precursors in tissues such as the testes, gut, and activated immune cells are key remnants of this evolutionary role.
Collapse
Affiliation(s)
- Alden Y Huang
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Anna M W Taylor
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Atefeh Ghogha
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Mochtar Pribadi
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Qing Wang
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Tanya S J Kim
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Catherine M Cahill
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Giovanni Coppola
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Christopher J Evans
- Department of Psychiatry and Biobehavioral Sciences, Shirley and Stefan Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| |
Collapse
|
2
|
Fricker LD, Margolis EB, Gomes I, Devi LA. Five Decades of Research on Opioid Peptides: Current Knowledge and Unanswered Questions. Mol Pharmacol 2020; 98:96-108. [PMID: 32487735 DOI: 10.1124/mol.120.119388] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 05/06/2020] [Indexed: 12/20/2022] Open
Abstract
In the mid-1970s, an intense race to identify endogenous substances that activated the same receptors as opiates resulted in the identification of the first endogenous opioid peptides. Since then, >20 peptides with opioid receptor activity have been discovered, all of which are generated from three precursors, proenkephalin, prodynorphin, and proopiomelanocortin, by sequential proteolytic processing by prohormone convertases and carboxypeptidase E. Each of these peptides binds to all three of the opioid receptor types (μ, δ, or κ), albeit with differing affinities. Peptides derived from proenkephalin and prodynorphin are broadly distributed in the brain, and mRNA encoding all three precursors are highly expressed in some peripheral tissues. Various approaches have been used to explore the functions of the opioid peptides in specific behaviors and brain circuits. These methods include directly administering the peptides ex vivo (i.e., to excised tissue) or in vivo (in animals), using antagonists of opioid receptors to infer endogenous peptide activity, and genetic knockout of opioid peptide precursors. Collectively, these studies add to our current understanding of the function of endogenous opioids, especially when similar results are found using different approaches. We briefly review the history of identification of opioid peptides, highlight the major findings, address several myths that are widely accepted but not supported by recent data, and discuss unanswered questions and future directions for research. SIGNIFICANCE STATEMENT: Activation of the opioid receptors by opiates and synthetic drugs leads to central and peripheral biological effects, including analgesia and respiratory depression, but these may not be the primary functions of the endogenous opioid peptides. Instead, the opioid peptides play complex and overlapping roles in a variety of systems, including reward pathways, and an important direction for research is the delineation of the role of individual peptides.
Collapse
Affiliation(s)
- Lloyd D Fricker
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York (L.D.F.); Department of Neurology, UCSF Weill Institute for Neurosciences, San Francisco, California (E.B.M.); and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (I.G., L.A.D.)
| | - Elyssa B Margolis
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York (L.D.F.); Department of Neurology, UCSF Weill Institute for Neurosciences, San Francisco, California (E.B.M.); and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (I.G., L.A.D.)
| | - Ivone Gomes
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York (L.D.F.); Department of Neurology, UCSF Weill Institute for Neurosciences, San Francisco, California (E.B.M.); and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (I.G., L.A.D.)
| | - Lakshmi A Devi
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York (L.D.F.); Department of Neurology, UCSF Weill Institute for Neurosciences, San Francisco, California (E.B.M.); and Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York (I.G., L.A.D.)
| |
Collapse
|
3
|
Gorr SU, Huang XF, Cowley DJ, Kuliawat R, Arvan P. Disruption of disulfide bonds exhibits differential effects on trafficking of regulated secretory proteins. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:C121-31. [PMID: 10409115 DOI: 10.1152/ajpcell.1999.277.1.c121] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
For several secretory proteins, it has been hypothesized that disulfide-bonded loop structures are required for sorting to secretory granules. To explore this hypothesis, we employed dithiothreitol (DTT) treatment in live pancreatic islets, as well as in PC-12 and GH(4)C(1) cells. In islets, disulfide reduction in the distal secretory pathway did not increase constitutive or constitutive-like secretion of proinsulin (or insulin). In PC-12 cells, DTT treatment caused a dramatic increase in unstimulated secretion of newly synthesized chromogranin B (CgB), presumably as a consequence of reducing the single conserved chromogranin disulfide bond (E. Chanat, U. Weiss, W. B. Huttner, and S. A. Tooze. EMBO J. 12: 2159-2168, 1993). However, in GH(4)C(1) cells that also synthesize CgB endogenously, DTT treatment reduced newly synthesized prolactin and blocked its export, whereas newly synthesized CgB was routed normally to secretory granules. Moreover, on transient expression in GH(4)C(1) cells, CgA and a CgA mutant lacking the conserved disulfide bond showed comparable multimeric aggregation properties and targeting to secretory granules, as measured by stimulated secretion assays. Thus the conformational perturbation of regulated secretory proteins caused by disulfide disruption leads to consequences in protein trafficking that are both protein and cell type dependent.
Collapse
Affiliation(s)
- S U Gorr
- Department of Biological and Biophysical Sciences, University of Louisville Health Sciences Center, Louisville, Kentucky 40292, USA
| | | | | | | | | |
Collapse
|