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Filler AG, Whiteside GT, Bacon M, Frederickson M, Howe FA, Rabinowitz MD, Sokoloff AJ, Deacon TW, Abell C, Munglani R, Griffiths JR, Bell BA, Lever AML. Tri-partite complex for axonal transport drug delivery achieves pharmacological effect. BMC Neurosci 2010; 11:8. [PMID: 20085661 PMCID: PMC2837052 DOI: 10.1186/1471-2202-11-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 01/20/2010] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Targeted delivery of pharmaceutical agents into selected populations of CNS (Central Nervous System) neurons is an extremely compelling goal. Currently, systemic methods are generally used for delivery of pain medications, anti-virals for treatment of dermatomal infections, anti-spasmodics, and neuroprotectants. Systemic side effects or undesirable effects on parts of the CNS that are not involved in the pathology limit efficacy and limit clinical utility for many classes of pharmaceuticals. Axonal transport from the periphery offers a possible selective route, but there has been little progress towards design of agents that can accomplish targeted delivery via this intraneural route. To achieve this goal, we developed a tripartite molecular construction concept involving an axonal transport facilitator molecule, a polymer linker, and a large number of drug molecules conjugated to the linker, then sought to evaluate its neurobiology and pharmacological behavior. RESULTS We developed chemical synthesis methodologies for assembling these tripartite complexes using a variety of axonal transport facilitators including nerve growth factor, wheat germ agglutinin, and synthetic facilitators derived from phage display work. Loading of up to 100 drug molecules per complex was achieved. Conjugation methods were used that allowed the drugs to be released in active form inside the cell body after transport. Intramuscular and intradermal injection proved effective for introducing pharmacologically effective doses into selected populations of CNS neurons. Pharmacological efficacy with gabapentin in a paw withdrawal latency model revealed a ten fold increase in half life and a 300 fold decrease in necessary dose relative to systemic administration for gabapentin when the drug was delivered by axonal transport using the tripartite vehicle. CONCLUSION Specific targeting of selected subpopulations of CNS neurons for drug delivery by axonal transport holds great promise. The data shown here provide a basic framework for the intraneural pharmacology of this tripartite complex. The pharmacologically efficacious drug delivery demonstrated here verify the fundamental feasibility of using axonal transport for targeted drug delivery.
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Affiliation(s)
- Aaron G Filler
- Institute for Nerve Medicine, 2716 Ocean Park Blvd., Suite 3082, Santa Monica, CA, 90405, USA
- Department of Cell and Molecular Biology, St. George's Hospital Medical School, University of London, Cranmer Terrace, London, SW17 ORE, UK
- Department of Neurosurgery, Atkinson Morley's Hospital, St. George's, University of London, 31 Copse Hill Road, London SW20 ONE, UK
- Division of Neurosurgery, UCLA School of Medicine, Center for Health Sciences, 10833 Le Conte Ave, Los Angeles, CA, 90095, USA
- SynGenix LTD, Babraham Hall, Babraham Research Campus, Cambridge, CB22 3AT, UK
- Molecular Synthetics LTD, Babraham Hall, Babraham Research Campus, Cambridge, CB22 3AT, UK
- Department of Organismic & Evolutionary Biology, Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138, USA
- Department of Anthropology, Human Evolutionary Biology, Peabody Museum, Harvard University, 11 Divinity Ave., Cambridge, MA, 02138, USA
| | - Garth T Whiteside
- SynGenix LTD, Babraham Hall, Babraham Research Campus, Cambridge, CB22 3AT, UK
- Wyeth Research, Neuroscience Discovery Research, CN 8000 Princeton, NJ, 08543, USA
| | - Mark Bacon
- SynGenix LTD, Babraham Hall, Babraham Research Campus, Cambridge, CB22 3AT, UK
- Molecular Synthetics LTD, Babraham Hall, Babraham Research Campus, Cambridge, CB22 3AT, UK
- Spinal Research, Station Road, Bramley, Guildford, Surrey, GU5 0AZ, UK
| | - Martyn Frederickson
- SynGenix LTD, Babraham Hall, Babraham Research Campus, Cambridge, CB22 3AT, UK
- Astex Therapeutics, 436 Cambridge Science Park, Milton Road, Cambridge, CB4 0QA, UK
- Department of Chemistry, University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Franklyn A Howe
- Department of Cell and Molecular Biology, St. George's Hospital Medical School, University of London, Cranmer Terrace, London, SW17 ORE, UK
| | - Miri D Rabinowitz
- Carmell Therapeutics Corporation, 10 South Tower, 320 E. North Ave., Pittsburgh, PA 15212, USA
- Department of Anthropology, Human Evolutionary Biology, Peabody Museum, Harvard University, 11 Divinity Ave., Cambridge, MA, 02138, USA
| | - Alan J Sokoloff
- Department of Physiology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
- Department of Anthropology, Human Evolutionary Biology, Peabody Museum, Harvard University, 11 Divinity Ave., Cambridge, MA, 02138, USA
| | - Terrence W Deacon
- Department of Anthropology, Human Evolutionary Biology, Peabody Museum, Harvard University, 11 Divinity Ave., Cambridge, MA, 02138, USA
- Department of Anthropology, University of California at Berkeley, 232 Kroeber Hall, Berkeley, CA 94720, USA
| | - Chris Abell
- Department of Chemistry, University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Raj Munglani
- Department of Anesthesia, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge, CB2 2QQ, UK
| | - John R Griffiths
- Department of Cell and Molecular Biology, St. George's Hospital Medical School, University of London, Cranmer Terrace, London, SW17 ORE, UK
- Molecular Imaging, Cancer Research UK Cambridge Research Institute, Robinson Way, Cambridge, CB2 ORE, UK
| | - B Anthony Bell
- Department of Neurosurgery, Atkinson Morley's Hospital, St. George's, University of London, 31 Copse Hill Road, London SW20 ONE, UK
- Neuroscience Unit, St. George's University of London, Cranmer Terrace, London, SW17 ORE, UK
| | - Andrew ML Lever
- SynGenix LTD, Babraham Hall, Babraham Research Campus, Cambridge, CB22 3AT, UK
- Department of Internal Medicine, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge, CB2 2QQ, UK
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Rahman W, Bauer CS, Bannister K, Vonsy JL, Dolphin AC, Dickenson AH. Descending serotonergic facilitation and the antinociceptive effects of pregabalin in a rat model of osteoarthritic pain. Mol Pain 2009; 5:45. [PMID: 19664204 PMCID: PMC2744671 DOI: 10.1186/1744-8069-5-45] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 08/07/2009] [Indexed: 12/29/2022] Open
Abstract
Background Descending facilitation, from the brainstem, promotes spinal neuronal hyperexcitability and behavioural hypersensitivity in many chronic pain states. We have previously demonstrated enhanced descending facilitation onto dorsal horn neurones in a neuropathic pain model, and shown this to enable the analgesic effectiveness of gabapentin. Here we have tested if this hypothesis applies to other pain states by using a combination of approaches in a rat model of osteoarthritis (OA) to ascertain if 1) a role for descending 5HT mediated facilitation exists, and 2) if pregabalin (a newer analogue of gabapentin) is an effective antinociceptive agent in this model. Further, quantitative-PCR experiments were undertaken to analyse the α2δ-1 and 5-HT3A subunit mRNA levels in L3–6 DRG in order to assess whether changes in these molecular substrates have a bearing on the pharmacological effects of ondansetron and pregabalin in OA. Results Osteoarthritis was induced via intra-articular injection of monosodium iodoacetate (MIA) into the knee joint. Control animals were injected with 0.9% saline. Two weeks later in vivo electrophysiology was performed, comparing the effects of spinal ondansetron (10–100 μg/50 μl) or systemic pregabalin (0.3 – 10 mg/kg) on evoked responses of dorsal horn neurones to electrical, mechanical and thermal stimuli in MIA or control rats. In MIA rats, ondansetron significantly inhibited the evoked responses to both innocuous and noxious natural evoked neuronal responses, whereas only inhibition of noxious evoked responses was seen in controls. Pregabalin significantly inhibited neuronal responses in the MIA rats only; this effect was blocked by a pre-administration of spinal ondansetron. Analysis of α2δ-1 and 5-HT3A subunit mRNA levels in L3–6 DRG revealed a significant increase in α2δ-1 levels in ipsilateral L3&4 DRG in MIA rats. 5-HT3A subunit mRNA levels were unchanged. Conclusion These data suggest descending serotonergic facilitation plays a role in mediating the brush and innocuous mechanical punctate evoked neuronal responses in MIA rats, suggesting an adaptive change in the excitatory serotonergic drive modulating low threshold evoked neuronal responses in MIA-induced OA pain. This alteration in excitatory serotonergic drive, alongside an increase in α2δ-1 mRNA levels, may underlie pregabalin's state dependent effects in this model of chronic pain.
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Affiliation(s)
- Wahida Rahman
- Department of Neuroscience, Pharmacology and Physiology, University College London, Gower Street, London, WC1E 6BT, UK.
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