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Da Vitoria Lobo ME, Weir N, Hardowar L, Al Ojaimi Y, Madden R, Gibson A, Bestall SM, Hirashima M, Schaffer CB, Donaldson LF, Bates DO, Hulse RP. Hypoxia-induced carbonic anhydrase mediated dorsal horn neuron activation and induction of neuropathic pain. Pain 2022; 163:2264-2279. [PMID: 35353768 PMCID: PMC9578530 DOI: 10.1097/j.pain.0000000000002627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 02/17/2022] [Accepted: 02/23/2022] [Indexed: 11/27/2022]
Abstract
ABSTRACT Neuropathic pain, such as that seen in diabetes mellitus, results in part from central sensitisation in the dorsal horn. However, the mechanisms responsible for such sensitisation remain unclear. There is evidence that disturbances in the integrity of the spinal vascular network can be causative factors in the development of neuropathic pain. Here we show that reduced blood flow and vascularity of the dorsal horn leads to the onset of neuropathic pain. Using rodent models (type 1 diabetes and an inducible endothelial-specific vascular endothelial growth factor receptor 2 knockout mouse) that result in degeneration of the endothelium in the dorsal horn, we show that spinal cord vasculopathy results in nociceptive behavioural hypersensitivity. This also results in increased hypoxia in dorsal horn neurons, depicted by increased expression of hypoxia markers such as hypoxia inducible factor 1α, glucose transporter 3, and carbonic anhydrase 7. Furthermore, inducing hypoxia through intrathecal delivery of dimethyloxalylglycine leads to the activation of dorsal horn neurons as well as mechanical and thermal hypersensitivity. This shows that hypoxic signalling induced by reduced vascularity results in increased hypersensitivity and pain. Inhibition of carbonic anhydrase activity, through intraperitoneal injection of acetazolamide, inhibited hypoxia-induced pain behaviours. This investigation demonstrates that induction of a hypoxic microenvironment in the dorsal horn, as occurs in diabetes, is an integral process by which neurons are activated to initiate neuropathic pain states. This leads to the conjecture that reversing hypoxia by improving spinal cord microvascular blood flow could reverse or prevent neuropathic pain.
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Affiliation(s)
- Marlene E. Da Vitoria Lobo
- Division of Cancer and Stem Cells, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
| | - Nick Weir
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Lydia Hardowar
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Yara Al Ojaimi
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Ryan Madden
- Division of Cancer and Stem Cells, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
| | - Alex Gibson
- Division of Cancer and Stem Cells, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
| | - Samuel M. Bestall
- Pain Centre Versus Arthritis and School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham, United Kingdom
| | - Masanori Hirashima
- Division of Pharmacology, Niigata University Graduate School of Medical and Dental Sciences, Japan
| | - Chris B. Schaffer
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, United States
| | - Lucy F. Donaldson
- Pain Centre Versus Arthritis and School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham, United Kingdom
| | - David O. Bates
- Division of Cancer and Stem Cells, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
- Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, United Kingdom
| | - Richard Philip Hulse
- Division of Cancer and Stem Cells, School of Medicine, Biodiscovery Institute, University of Nottingham, Nottingham, United Kingdom
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
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Bestall SM, Hulse RP, Blackley Z, Swift M, Ved N, Paton K, Beazley-Long N, Bates DO, Donaldson LF. Sensory neuronal sensitisation occurs through HMGB-1-RAGE and TRPV1 in high-glucose conditions. J Cell Sci 2018; 131:jcs215939. [PMID: 29930087 PMCID: PMC6080605 DOI: 10.1242/jcs.215939] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 06/14/2018] [Indexed: 01/01/2023] Open
Abstract
Many potential causes for painful diabetic neuropathy have been proposed including actions of cytokines and growth factors. High mobility group protein B1 (HMGB1) is a RAGE (also known as AGER) agonist whose levels are increased in diabetes and that contributes to pain by modulating peripheral inflammatory responses. HMGB1 enhances nociceptive behaviour in naïve animals through an unknown mechanism. We tested the hypothesis that HMGB1 causes pain through direct neuronal activation of RAGE and alteration of nociceptive neuronal responsiveness. HMGB1 and RAGE expression were increased in skin and primary sensory (dorsal root ganglion, DRG) neurons of diabetic rats at times when pain behaviour was enhanced. Agonist-evoked TRPV1-mediated Ca2+ responses increased in cultured DRG neurons from diabetic rats and in neurons from naïve rats exposed to high glucose concentrations. HMGB1-mediated increases in TRPV1-evoked Ca2+ responses in DRG neurons were RAGE- and PKC-dependent, and this was blocked by co-administration of the growth factor splice variant VEGF-A165b. Pain behaviour and the DRG RAGE expression increases were blocked by VEGF-A165b treatment of diabetic rats in vivo Hence, we conclude that HMGB1-RAGE activation sensitises DRG neurons in vitro, and that VEGF-A165b blocks HMGB-1-RAGE DRG activation, which may contribute to its analgesic properties in vivo.
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Affiliation(s)
- Samuel M Bestall
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Richard P Hulse
- Arthritis Research UK Pain Centre, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Zoe Blackley
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Matthew Swift
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
- Cancer Biology, School of Clinical Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Nikita Ved
- Arthritis Research UK Pain Centre, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
- Institute of Ophthalmology, 11-43 Bath St, London EC1V 9EL, UK
| | - Kenneth Paton
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Nicholas Beazley-Long
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
- Arthritis Research UK Pain Centre, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - David O Bates
- Cancer Biology, School of Clinical Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Lucy F Donaldson
- School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
- Arthritis Research UK Pain Centre, The Medical School QMC, University of Nottingham, Nottingham NG7 2UH, UK
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Ved N, Da Vitoria Lobo ME, Bestall SM, L Vidueira C, Beazley-Long N, Ballmer-Hofer K, Hirashima M, Bates DO, Donaldson LF, Hulse RP. Diabetes-induced microvascular complications at the level of the spinal cord: a contributing factor in diabetic neuropathic pain. J Physiol 2018; 596:3675-3693. [PMID: 29774557 PMCID: PMC6092307 DOI: 10.1113/jp275067] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 05/08/2018] [Indexed: 02/06/2023] Open
Abstract
KEY POINTS Diabetes is thought to induce neuropathic pain through activation of dorsal horn sensory neurons in the spinal cord. Here we explore the impact of hyperglycaemia on the blood supply supporting the spinal cord and chronic pain development. In streptozotocin-induced diabetic rats, neuropathic pain is accompanied by a decline in microvascular integrity in the dorsal horn. Hyperglycaemia-induced degeneration of the endothelium in the dorsal horn was associated with a loss in vascular endothelial growth factor (VEGF)-A165 b expression. VEGF-A165 b treatment prevented diabetic neuropathic pain and degeneration of the endothelium in the spinal cord. Using an endothelial-specific VEGFR2 knockout transgenic mouse model, the loss of endothelial VEGFR2 signalling led to a decline in vascular integrity in the dorsal horn and the development of hyperalgesia in VEGFR2 knockout mice. This highlights that vascular degeneration in the spinal cord could be a previously unidentified factor in the development of diabetic neuropathic pain. ABSTRACT Abnormalities of neurovascular interactions within the CNS of diabetic patients is associated with the onset of many neurological disease states. However, to date, the link between the neurovascular network within the spinal cord and regulation of nociception has not been investigated despite neuropathic pain being common in diabetes. We hypothesised that hyperglycaemia-induced endothelial degeneration in the spinal cord, due to suppression of vascular endothelial growth factor (VEGF)-A/VEGFR2 signalling, induces diabetic neuropathic pain. Nociceptive pain behaviour was investigated in a chemically induced model of type 1 diabetes (streptozotocin induced, insulin supplemented; either vehicle or VEGF-A165 b treated) and an inducible endothelial knockdown of VEGFR2 (tamoxifen induced). Diabetic animals developed mechanical allodynia and heat hyperalgesia. This was associated with a reduction in the number of blood vessels and reduction in Evans blue extravasation in the lumbar spinal cord of diabetic animals versus age-matched controls. Endothelial markers occludin, CD31 and VE-cadherin were downregulated in the spinal cord of the diabetic group versus controls, and there was a concurrent reduction of VEGF-A165 b expression. In diabetic animals, VEGF-A165 b treatment (biweekly i.p., 20 ng g-1 ) restored normal Evans blue extravasation and prevented vascular degeneration, diabetes-induced central neuron activation and neuropathic pain. Inducible knockdown of VEGFR2 (tamoxifen treated Tie2CreERT2 -vegfr2flfl mice) led to a reduction in blood vessel network volume in the lumbar spinal cord and development of heat hyperalgesia. These findings indicate that hyperglycaemia leads to a reduction in the VEGF-A/VEGFR2 signalling cascade, resulting in endothelial dysfunction in the spinal cord, which could be an undiscovered contributing factor to diabetic neuropathic pain.
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Affiliation(s)
- N Ved
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine University of Nottingham, Nottingham, NG7 2UH, UK.,Institute of Ophthalmology, 11-43 Bath St, London, EC1V 9EL, UK.,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - M E Da Vitoria Lobo
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine University of Nottingham, Nottingham, NG7 2UH, UK
| | - S M Bestall
- Arthritis Research UK Pain Centre and School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham, NG7 2UH, UK
| | - C L Vidueira
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine University of Nottingham, Nottingham, NG7 2UH, UK
| | - N Beazley-Long
- Arthritis Research UK Pain Centre and School of Life Sciences, The Medical School QMC, University of Nottingham, Nottingham, NG7 2UH, UK
| | | | - M Hirashima
- Division of Vascular Biology, Kobe University, Japan
| | - D O Bates
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine University of Nottingham, Nottingham, NG7 2UH, UK.,Centre of Membrane and Protein and Receptors (COMPARE), University of Birmingham, Birmingham and University of Nottingham, Nottingham, UK
| | - L F Donaldson
- Institute of Ophthalmology, 11-43 Bath St, London, EC1V 9EL, UK
| | - R P Hulse
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine University of Nottingham, Nottingham, NG7 2UH, UK.,School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, UK
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