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Minett MS, Pereira V, Sikandar S, Matsuyama A, Lolignier S, Kanellopoulos AH, Mancini F, Iannetti GD, Bogdanov YD, Santana-Varela S, Millet Q, Baskozos G, MacAllister R, Cox JJ, Zhao J, Wood JN. Endogenous opioids contribute to insensitivity to pain in humans and mice lacking sodium channel Nav1.7. Nat Commun 2015; 6:8967. [PMID: 26634308 PMCID: PMC4686868 DOI: 10.1038/ncomms9967] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 10/21/2015] [Indexed: 12/14/2022] Open
Abstract
Loss-of-function mutations in the SCN9A gene encoding voltage-gated sodium channel Nav1.7 cause congenital insensitivity to pain in humans and mice. Surprisingly, many potent selective antagonists of Nav1.7 are weak analgesics. We investigated whether Nav1.7, as well as contributing to electrical signalling, may have additional functions. Here we report that Nav1.7 deletion has profound effects on gene expression, leading to an upregulation of enkephalin precursor Penk mRNA and met-enkephalin protein in sensory neurons. In contrast, Nav1.8-null mutant sensory neurons show no upregulated Penk mRNA expression. Application of the opioid antagonist naloxone potentiates noxious peripheral input into the spinal cord and dramatically reduces analgesia in both female and male Nav1.7-null mutant mice, as well as in a human Nav1.7-null mutant. These data suggest that Nav1.7 channel blockers alone may not replicate the analgesic phenotype of null mutant humans and mice, but may be potentiated with exogenous opioids.
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Affiliation(s)
- Michael S. Minett
- Molecular Nociception Group, WIBR, University College London, Gower Street, London WC1E 6BT, UK
| | - Vanessa Pereira
- Molecular Nociception Group, WIBR, University College London, Gower Street, London WC1E 6BT, UK
| | - Shafaq Sikandar
- Molecular Nociception Group, WIBR, University College London, Gower Street, London WC1E 6BT, UK
| | - Ayako Matsuyama
- Molecular Nociception Group, WIBR, University College London, Gower Street, London WC1E 6BT, UK
| | - Stéphane Lolignier
- Molecular Nociception Group, WIBR, University College London, Gower Street, London WC1E 6BT, UK
| | | | - Flavia Mancini
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Gian D. Iannetti
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Yury D. Bogdanov
- Molecular Nociception Group, WIBR, University College London, Gower Street, London WC1E 6BT, UK
| | - Sonia Santana-Varela
- Molecular Nociception Group, WIBR, University College London, Gower Street, London WC1E 6BT, UK
| | - Queensta Millet
- Molecular Nociception Group, WIBR, University College London, Gower Street, London WC1E 6BT, UK
| | - Giorgios Baskozos
- Institute of Structural and Molecular Biology, UCL, London WC1E 6BT, UK
| | | | - James J. Cox
- Molecular Nociception Group, WIBR, University College London, Gower Street, London WC1E 6BT, UK
| | - Jing Zhao
- Molecular Nociception Group, WIBR, University College London, Gower Street, London WC1E 6BT, UK
| | - John N. Wood
- Molecular Nociception Group, WIBR, University College London, Gower Street, London WC1E 6BT, UK
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Rato L, Socorro S, Cavaco JEB, Oliveira PF. Tubular Fluid Secretion in the Seminiferous Epithelium: Ion Transporters and Aquaporins in Sertoli Cells. J Membr Biol 2010; 236:215-24. [DOI: 10.1007/s00232-010-9294-x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Accepted: 07/20/2010] [Indexed: 01/01/2023]
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Hemachand T, Gopalakrishnan B, Salunke DM, Totey SM, Shaha C. Sperm plasma-membrane-associated glutathione S-transferases as gamete recognition molecules. J Cell Sci 2002; 115:2053-65. [PMID: 11973347 DOI: 10.1242/jcs.115.10.2053] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glutathione S-transferases (GSTs) are enzymes that detoxify electrophilic compounds. Earlier studies from our laboratory showed that anti-GST antibodies interfered with the fertilising ability of spermatozoa from Capra hircus (goat) in vitro, suggesting that GSTs are localised at the cell surface. In this study, we provide evidence for the presence of GSTs of 24 kDa on the sperm plasma membrane attached by non-covalent interactions. The GST activity associated with the spermatozoal plasma membrane was significantly higher than the activity present in the plasma membranes of brain cells,hepatocytes, spleenocytes and ventriculocytes. Analysis of GST isoforms demonstrates the presence of GST Pi and Mu on the sperm plasma membranes. Both isoforms were able to bind to solubilised as well as intact zona pellucida(ZP) through their N-terminal regions but failed to bind to ZP once the oocytes were fertilised. Solubilised goat ZP separates into three components,one of which, the ZP3-like component, bound to sperm GSTs. High concentrations of anti-GST antibodies or solubilised ZP led to aggregation of sperm GSTs,resulting in the release of acrosin. In contrast, inhibition of sperm GST binding to ZP, by saturation of binding sites for sperm GSTs on the solubilised ZP using peptides designed from the N-terminii of GST Pi or Mu or blocking of binding sites for ZP on sperm GSTs with antibodies raised against the N-terminal GST peptides, inhibited essential prefertilisation changes in sperm.
These data therefore demonstrate the strategic location of catalytically active defensive enzymes on the sperm surface that also act as zona-binding proteins. Therefore, sperm-surface GSTs serve as bifunctional molecules in a transcriptionally inactive cell whose requirement for cellular defense and economy of molecules that it can carry is greater than that of any somatic cell type.
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Affiliation(s)
- Tummala Hemachand
- National Institute of Immunology, Aruna Asaf Ali Road, New Delhi 110067, India
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Ko WH, Chan HC, Chew SB, Wong PY. Regulated anion secretion in cultured epithelia from Sertoli cells of immature rats. J Physiol 1998; 512 ( Pt 2):471-80. [PMID: 9763636 PMCID: PMC2231224 DOI: 10.1111/j.1469-7793.1998.471be.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/1997] [Accepted: 06/26/1998] [Indexed: 12/29/2022] Open
Abstract
1. Cultured epithelia of Sertoli cells from prepubertal rats were grown on Matrigel-coated millipore filters for short-circuit current (Isc) measurements. Under basal conditions, these epithelia exhibited a 'zero' transepithelial potential difference, a 'zero' short-circuit current and a transepithelial resistance of 60 Omega cm2. 2. Forskolin (100 microM) and 8-(4-chlorophenylthio)-cAMP (cpt-cAMP) (100 microM) added to the apical side stimulated the Isc (forskolin, peak DeltaIsc = 1.32 +/- 0.16 microA cm-1; cpt-cAMP, peak DeltaIsc = 0.88 +/- 0.16 microA cm-2). 3. ATP (100 microM) added apically elicited a Isc response (peak DeltaIsc = 6.45 +/- 0. 28 microA cm-2) which was similar in magnitude to that of 1 microM thapsigargin (peak DeltaIsc = 6.09 +/- 0.44 microA cm-2). The potency of the responses to other nucleotides: UTP >= ATP > ADP >> AMP = adenosine indicates the involvement of a mixture of P2Y receptors. 4. Removal of extracellular Cl- and HCO3- reduced the Isc response to ATP by 70 % and 40 %, respectively. Removal of K+ had no effect, whereas removal of Na+ attenuated the Isc response. 5. The response to ATP was insensitive to agents known to block anion secretion (except apical diphenylamine-2-carboxylate (DPC) and DIDS). The resistance to perturbation by pharmacological agents may be a unique property of the seminiferous epithelium. 6. Whole-cell current recordings in cultured rat Sertoli cells demonstrated a DIDS-sensitive outwardly rectifying Cl- conductance with activating and inactivating characteristics at depolarizing and hyperpolarizing voltages, respectively. 7. The stimulation of electrogenic ion transport by ATP may be part of a complex mechanism regulating fluid secretion by the testis. Cultured Sertoli cell epithelia are shown to provide a useful model to investigate transepithelial transport in the seminiferous epithelium.
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Affiliation(s)
- W H Ko
- Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China
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