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McCoull D, Veale EL, Walsh Y, Byrom L, Avkiran T, Large JM, Vaitone E, Gaffey F, Jerman J, Mathie A, Wright PD. Aprepitant is a novel, selective activator of the K2P channel TRAAK. Biochem Biophys Res Commun 2021; 588:41-46. [PMID: 34942533 DOI: 10.1016/j.bbrc.2021.12.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 12/12/2021] [Indexed: 11/02/2022]
Abstract
TRAAK (KCNK4, K2P4.1) is a mechanosensitive two-pore domain potassium (K2P) channel. Due to its expression within sensory neurons and genetic link to neuropathic pain it represents a promising potential target for novel analgesics. In common with many other channels in the wider K2P sub-family, there remains a paucity of small molecule pharmacological tools. Specifically, there is a lack of molecules selective for TRAAK over the other members of the TREK subfamily of K2P channels. We developed a thallium flux assay to allow high throughput screening of compounds and facilitate the identification of novel TRAAK activators. Using a library of ∼1200 drug like molecules we identified Aprepitant as a small molecule activator of TRAAK. Aprepitant is an NK-1 antagonist used to treat nausea and vomiting. Close structural analogues of Aprepitant and a range of NK-1 antagonists were also selected or designed for purchase or brief chemical synthesis and screened for their ability to activate TRAAK. Electrophysiology experiments confirmed that Aprepitant activates both the 'long' and 'short' transcript variants of TRAAK. We also demonstrated that Aprepitant is selective and does not activate other members of the K2P superfamily. This work describes the development of a high throughput assay to identify potential TRAAK activators and subsequent identification and confirmation of the novel TRAAK activator Aprepitant. This discovery identifies a useful tool compound which can be used to further probe the function of TRAAK K2P channels.
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Affiliation(s)
- D McCoull
- LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, SG1 2FX, UK.
| | - E L Veale
- Medway School of Pharmacy, University of Greenwich and University of Kent, Anson Building, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Y Walsh
- Medway School of Pharmacy, University of Greenwich and University of Kent, Anson Building, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - L Byrom
- LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, SG1 2FX, UK
| | - T Avkiran
- LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, SG1 2FX, UK
| | - J M Large
- LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, SG1 2FX, UK
| | - E Vaitone
- LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, SG1 2FX, UK
| | - F Gaffey
- LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, SG1 2FX, UK
| | - J Jerman
- LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, SG1 2FX, UK
| | - A Mathie
- Medway School of Pharmacy, University of Greenwich and University of Kent, Anson Building, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK; School of Engineering, Arts, Science and Technology, University of Suffolk, Ipswich, IP4 1QJ, UK
| | - P D Wright
- LifeArc, Accelerator Building, Open Innovation Campus, Stevenage, SG1 2FX, UK
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Doshi TL, Dworkin RH, Polomano RC, Carr DB, Edwards RR, Finnerup NB, Freeman RL, Paice JA, Weisman SJ, Raja SN. AAAPT Diagnostic Criteria for Acute Neuropathic Pain. PAIN MEDICINE 2021; 22:616-636. [PMID: 33575803 DOI: 10.1093/pm/pnaa407] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Acute neuropathic pain is a significant diagnostic challenge, and it is closely related to our understanding of both acute pain and neuropathic pain. Diagnostic criteria for acute neuropathic pain should reflect our mechanistic understanding and provide a framework for research on and treatment of these complex pain conditions. METHODS The Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership with the U.S. Food and Drug Administration (FDA), the American Pain Society (APS), and the American Academy of Pain Medicine (AAPM) collaborated to develop the ACTTION-APS-AAPM Pain Taxonomy (AAAPT) for acute pain. A working group of experts in research and clinical management of neuropathic pain was convened. Group members used literature review and expert opinion to develop diagnostic criteria for acute neuropathic pain, as well as three specific examples of acute neuropathic pain conditions, using the five dimensions of the AAAPT classification of acute pain. RESULTS AAAPT diagnostic criteria for acute neuropathic pain are presented. Application of these criteria to three specific conditions (pain related to herpes zoster, chemotherapy, and limb amputation) illustrates the spectrum of acute neuropathic pain and highlights unique features of each condition. CONCLUSIONS The proposed AAAPT diagnostic criteria for acute neuropathic pain can be applied to various acute neuropathic pain conditions. Both the general and condition-specific criteria may guide future research, assessment, and management of acute neuropathic pain.
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Affiliation(s)
- Tina L Doshi
- Department of Anesthesiology and Critical Care Medicine, Division of Pain Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Robert H Dworkin
- Department of Anesthesiology, University of Rochester School of Medicine and Dentistry, Rochester, New York, and Department of Neurology, Center for Human Experimental Therapeutics, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Rosemary C Polomano
- Division of Biobehavioral Health Sciences, University of Pennsylvania-School of Nursing, Philadelphia, Pennsylvania, USA
| | - Daniel B Carr
- Public Health and Community Medicine Program, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Robert R Edwards
- Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Nanna B Finnerup
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, and Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Roy L Freeman
- Center for Autonomic and Peripheral Nerve Disorders, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Judith A Paice
- Cancer Pain Program, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
| | - Steven J Weisman
- Jane B. Pettit Pain and Headache Center, Children's Wisconsin, Departments of Anesthesiology and Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Srinivasa N Raja
- Department of Anesthesiology and Critical Care Medicine, Division of Pain Medicine, Johns Hopkins University, Baltimore, Maryland, USA
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McCoull D, Ococks E, Large JM, Tickle DC, Mathie A, Jerman J, Wright PD. A "Target Class" Screen to Identify Activators of Two-Pore Domain Potassium (K2P) Channels. SLAS DISCOVERY 2020; 26:428-438. [PMID: 33375888 PMCID: PMC7900820 DOI: 10.1177/2472555220976126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Two-pore domain potassium (K2P) channels carry background (or leak) potassium
current and play a key role in regulating resting membrane potential and
cellular excitability. Accumulating evidence points to a role for K2Ps in human
pathophysiologies, most notably in pain and migraine, making them attractive
targets for therapeutic intervention. However, there remains a lack of selective
pharmacological tools. The aim of this work was to apply a “target class”
approach to investigate the K2P superfamily and identify novel activators across
all the described subclasses of K2P channels. Target class drug discovery allows
for the leveraging of accumulated knowledge and maximizing synergies across a
family of targets and serves as an additional approach to standard target-based
screening. A common assay platform using baculovirus (BacMam) to transiently
express K2P channels in mammalian cells and a thallium flux assay to determine
channel activity was developed, allowing the simultaneous screening of multiple
targets. Importantly, this system, by allowing precise titration of channel
function, allows optimization to facilitate the identification of activators. A
representative set of channels (THIK-1, TWIK-1, TREK-2, TASK-3, and TASK-2) were
screened against a library of Food and Drug Administration (FDA)-approved
compounds and the LifeArc Index Set. Activators were then analyzed in
concentration–response format across all channels to assess selectivity. Using
the target class approach to investigate the K2P channels has enabled us to
determine which of the K2Ps are amenable to small-molecule activation, de-risk
multiple channels from a technical point of view, and identify a diverse range
of previously undescribed pharmacology.
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Affiliation(s)
| | | | | | | | - Alistair Mathie
- Medway School of Pharmacy, University of Kent, Chatham Maritime, Kent, UK
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Mathie A, Veale EL, Cunningham KP, Holden RG, Wright PD. Two-Pore Domain Potassium Channels as Drug Targets: Anesthesia and Beyond. Annu Rev Pharmacol Toxicol 2020; 61:401-420. [PMID: 32679007 DOI: 10.1146/annurev-pharmtox-030920-111536] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two-pore domain potassium (K2P) channels stabilize the resting membrane potential of both excitable and nonexcitable cells and, as such, are important regulators of cell activity. There are many conditions where pharmacological regulation of K2P channel activity would be of therapeutic benefit, including, but not limited to, atrial fibrillation, respiratory depression, pulmonary hypertension, neuropathic pain, migraine, depression, and some forms of cancer. Up until now, few if any selective pharmacological regulators of K2P channels have been available. However, recent publications of solved structures with small-molecule activators and inhibitors bound to TREK-1, TREK-2, and TASK-1 K2P channels have given insight into the pharmacophore requirements for compound binding to these sites. Together with the increasing availability of a number of novel, active, small-molecule compounds from K2P channel screening programs, these advances have opened up the possibility of rational activator and inhibitor design to selectively target K2P channels.
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Affiliation(s)
- Alistair Mathie
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
| | - Emma L Veale
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
| | - Kevin P Cunningham
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Robyn G Holden
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
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