1
|
Yang J, Cai JH, Wu TX, Gao ZQ, Zhou C, Wu Q, Ji MJ. Salvinorin A ameliorates pilocarpine-induced seizures by regulating hippocampal microglia polarization. JOURNAL OF ETHNOPHARMACOLOGY 2024; 335:118697. [PMID: 39154669 DOI: 10.1016/j.jep.2024.118697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 07/28/2024] [Accepted: 08/12/2024] [Indexed: 08/20/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Salvia divinorum (Epling and Játiva) is a psychoactive plant traditionally used by the Latinos for various medicinal purposes. Salvinorin A (Sal A), the main bioactive constituent of S. divinorum, is a natural highly selective kappa opioid receptor (KOR) agonist. Considering the anti-inflammatory effect of S. divinorum and endogenous hippocampal dynorphin/kappa opioid receptor (KOR) system playing an anticonvulsant function, we hypothesis that Sal A can be a potential candidate to treat epilepsy. Here, we identified whether Sal A ameliorated epileptic seizures and neuronal damages in animal model and in vitro model and investigated its underlying mechanisms. MATERIALS AND METHODS Mice epilepsy model was induced by pilocarpine following seizures assessed by Racine classification. Hippocampus tissues were obtained for genetic, protein, and histological investigation. Furthermore, lipopolysaccharide (LPS)-activated BV2 microglial cells were utilized to validate the anti-inflammatory and microglia polarization regulation effects of Sal A. RESULTS Sal A treatment significantly prolonged the latency to status epileptics (SE) and shortened the duration of SE in the pilocarpine-induced model. It also alleviated neuronal damages via activation of the AMPK/JNK/p-38 MAPK pathway and inhibition of apoptosis-related protein in hippocampus tissues. Furthermore, Sal A dose-dependently reduced microglia-mediated expression of pro-inflammatory cytokines and increased anti-inflammatory factors levels in SE mice and LPS-activated BV2 microglial cells by regulating microglia polarization. In addition, the effect of Sal A in vitro was totally blocked by KOR antagonist nor-BNI. CONCLUSION Sal A treatment protects against epileptic seizures and neuronal damages in pilocarpine-induced models by suppressing the inflammation response through regulating microglial M1/M2 polarization. This study might serve as a theoretical basis for clinical applications of Sal A and its analogs and provide a new insight into the development of anti-seizure drugs.
Collapse
Affiliation(s)
- Jiao Yang
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China; Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, 200030, China
| | - Ji-Heng Cai
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China; Department of Anesthesiology, Sheyang County People's Hospital, Yancheng, 224300, China.
| | - Tong-Xuan Wu
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
| | - Zhi-Qiang Gao
- School of Pharmacology, Xuzhou Medical University, Xuzhou, 221004, China
| | - Chao Zhou
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China
| | - Qi Wu
- Department of Physiology, Xuzhou Medical University, Xuzhou, 221004, China
| | - Miao-Jin Ji
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, 221004, China.
| |
Collapse
|
2
|
Widmann M, Lieb A, Fogli B, Steck A, Mutti A, Schwarzer C. Characterization of the intrahippocampal kainic acid model in female mice with a special focus on seizure suppression by antiseizure medications. Exp Neurol 2024; 376:114749. [PMID: 38467356 PMCID: PMC7615823 DOI: 10.1016/j.expneurol.2024.114749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 02/26/2024] [Accepted: 03/05/2024] [Indexed: 03/13/2024]
Abstract
Despite special challenges in the medical treatment of women with epilepsy, in particular preclinical animal studies were focused on males for decades and females have only recently moved into the focus of scientific interest. The intrahippocampal kainic acid (IHKA) mouse model of temporal lobe epilepsy (TLE) is one of the most studied models in males reproducing electroencephalographic (EEG) and histopathological features of human TLE. Hippocampal paroxysmal discharges (HPDs) were described as drug resistant focal seizures in males. Here, we investigated the IHKA model in female mice, in particular drug-resistance of HPDs and the influence of antiseizure medications (ASMs) on the power spectrum. After injecting kainic acid (KA) unilaterally into the hippocampus of female mice, we monitored the development of epileptiform activity by local field potential (LFP) recordings. Subsequently, we evaluated the effect of the commonly prescribed ASMs lamotrigine (LTG), oxcarbazepine (OXC) and levetiracetam (LEV), as well as the benzodiazepine diazepam (DZP) with a focus on HPDs and power spectral analysis and assessed neuropathological alterations of the hippocampus. In the IHKA model, female mice replicated key features of human TLE as previously described in males. Importantly, HPDs in female mice did not respond to commonly prescribed ASMs in line with the drug-resistance in males, thus representing a suitable model of drug-resistant seizures. Intriguingly, we observed an increased occurrence of generalized seizures after LTG. Power spectral analysis revealed a pronounced increase in the delta frequency range after the higher dose of 30 mg/kg LTG. DZP abolished HPDs and caused a marked reduction over a wide frequency range (delta, theta, and alpha) of the power spectrum. By characterizing the IHKA model of TLE in female mice we address an important gap in basic research. Considering the special challenges complicating the therapeutic management of epilepsy in women, inclusion of females in preclinical studies is imperative. A well-characterized female model is a prerequisite for the development of novel therapeutic strategies tailored to sex-specific needs and for studies on the effect of epilepsy and ASMs during pregnancy.
Collapse
Affiliation(s)
- Melanie Widmann
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
| | - Andreas Lieb
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
| | - Barbara Fogli
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Angela Steck
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
| | - Anna Mutti
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
| |
Collapse
|
3
|
Lankhuijzen LM, Ridler T. Opioids, microglia, and temporal lobe epilepsy. Front Neurol 2024; 14:1298489. [PMID: 38249734 PMCID: PMC10796828 DOI: 10.3389/fneur.2023.1298489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 12/15/2023] [Indexed: 01/23/2024] Open
Abstract
A lack of treatment options for temporal lobe epilepsy (TLE) demands an urgent quest for new therapies to recover neuronal damage and reduce seizures, potentially interrupting the neurotoxic cascades that fuel hyper-excitability. Endogenous opioids, along with their respective receptors, particularly dynorphin and kappa-opioid-receptor, present as attractive candidates for controlling neuronal excitability and therapeutics in epilepsy. We perform a critical review of the literature to evaluate the role of opioids in modulating microglial function and morphology in epilepsy. We find that, in accordance with anticonvulsant effects, acute opioid receptor activation has unique abilities to modulate microglial activation through toll-like 4 receptors, regulating downstream secretion of cytokines. Abnormal activation of microglia is a dominant feature of neuroinflammation, and inflammatory cytokines are found to aggravate TLE, inspiring the challenge to alter microglial activation by opioids to suppress seizures. We further evaluate how opioids can modulate microglial activation in epilepsy to enhance neuroprotection and reduce seizures. With controlled application, opioids may interrupt inflammatory cycles in epilepsy, to protect neuronal function and reduce seizures. Research on opioid-microglia interactions has important implications for epilepsy and healthcare approaches. However, preclinical research on opioid modulation of microglia supports a new therapeutic pathway for TLE.
Collapse
Affiliation(s)
| | - Thomas Ridler
- Hatherly Laboratories, Department of Clinical and Biomedical Sciences, University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| |
Collapse
|
4
|
Widmann M, Lieb A, Mutti A, Schwarzer C. Dimethyl sulfoxide's impact on epileptiform activity in a mouse model of chronic temporal lobe epilepsy. Epilepsy Res 2023; 197:107235. [PMID: 37797423 PMCID: PMC7615238 DOI: 10.1016/j.eplepsyres.2023.107235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/13/2023] [Accepted: 09/28/2023] [Indexed: 10/07/2023]
Abstract
In the quest for novel treatments for patients with drug-resistant seizures, poor water solubility of potential drug candidates is a frequent obstacle. Literature indicated that the highly efficient solvent dimethyl sulfoxide (DMSO) may have a confounding influence in epilepsy research, reporting both pro- and antiepileptic effects. In this study, we aim to clarify the effects of DMSO on epileptiform activity in one of the most frequently studied models of chronic epilepsy, the intrahippocampal kainic acid (IHKA) mouse model, and in a model of acute seizures. We show that 100 % DMSO (in a volume of 1.5 µl/g corresponding to 1651 mg/kg) causes a significant short-term anti-seizure effect in epileptic IHKA mice of both sexes, but does not affect the threshold of acute seizures induced by pentylenetetrazol (PTZ). These findings highlight that the choice of solvent and appropriate vehicle control is crucial to minimize undesirable misleading effects and that drug candidates exclusively soluble in 100 % DMSO need to be modified for better solubility already at initial testing.
Collapse
Affiliation(s)
- Melanie Widmann
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Andreas Lieb
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Anna Mutti
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
| |
Collapse
|
5
|
Ramos-Gonzalez N, Paul B, Majumdar S. IUPHAR themed review: Opioid efficacy, bias, and selectivity. Pharmacol Res 2023; 197:106961. [PMID: 37844653 DOI: 10.1016/j.phrs.2023.106961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/18/2023]
Abstract
Drugs acting at the opioid receptor family are clinically used to treat chronic and acute pain, though they represent the second line of treatment behind GABA analogs, antidepressants and SSRI's. Within the opioid family mu and kappa opioid receptor are commonly targeted. However, activation of the mu opioid receptor has side effects of constipation, tolerance, dependence, euphoria, and respiratory depression; activation of the kappa opioid receptor leads to dysphoria and sedation. The side effects of mu opioid receptor activation have led to mu receptor drugs being widely abused with great overdose risk. For these reasons, newer safer opioid analgesics are in high demand. For many years a focus within the opioid field was finding drugs that activated the G protein pathway at mu opioid receptor, without activating the β-arrestin pathway, known as biased agonism. Recent advances have shown that this may not be the way forward to develop safer analgesics at mu opioid receptor, though there is still some promise at the kappa opioid receptor. Here we discuss recent novel approaches to develop safer opioid drugs including efficacy vs bias and fine-tuning receptor activation by targeting sub-pockets in the orthosteric site, we explore recent works on the structural basis of bias, and we put forward the suggestion that Gα subtype selectivity may be an exciting new area of interest.
Collapse
Affiliation(s)
- Nokomis Ramos-Gonzalez
- Department of Anesthesiology and Washington University Pain Center, Washington University School of Medicine, Saint Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St. Louis and Washington University School of Medicine, St. Louis, MO, USA
| | - Barnali Paul
- Department of Anesthesiology and Washington University Pain Center, Washington University School of Medicine, Saint Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St. Louis and Washington University School of Medicine, St. Louis, MO, USA
| | - Susruta Majumdar
- Department of Anesthesiology and Washington University Pain Center, Washington University School of Medicine, Saint Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St. Louis and Washington University School of Medicine, St. Louis, MO, USA.
| |
Collapse
|
6
|
Varga B, Streicher JM, Majumdar S. Strategies towards safer opioid analgesics-A review of old and upcoming targets. Br J Pharmacol 2023; 180:975-993. [PMID: 34826881 PMCID: PMC9133275 DOI: 10.1111/bph.15760] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 10/08/2021] [Accepted: 11/05/2021] [Indexed: 11/30/2022] Open
Abstract
Opioids continue to be of use for the treatment of pain. Most clinically used analgesics target the μ opioid receptor whose activation results in adverse effects like respiratory depression, addiction and abuse liability. Various approaches have been used by the field to separate receptor-mediated analgesic actions from adverse effects. These include biased agonism, opioids targeting multiple receptors, allosteric modulators, heteromers and splice variants of the μ receptor. This review will focus on the current status of the field and some upcoming targets of interest that may lead to a safer next generation of analgesics. LINKED ARTICLES: This article is part of a themed issue on Advances in Opioid Pharmacology at the Time of the Opioid Epidemic. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v180.7/issuetoc.
Collapse
Affiliation(s)
- Balazs Varga
- Center for Clinical Pharmacology, University of Health Sciences and Pharmacy in St Louis and Washington University School of Medicine, St Louis, MO, USA
| | - John M. Streicher
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Susruta Majumdar
- Center for Clinical Pharmacology, University of Health Sciences and Pharmacy in St Louis and Washington University School of Medicine, St Louis, MO, USA
| |
Collapse
|
7
|
Khan MIH, Sawyer BJ, Akins NS, Le HV. A systematic review on the kappa opioid receptor and its ligands: New directions for the treatment of pain, anxiety, depression, and drug abuse. Eur J Med Chem 2022; 243:114785. [PMID: 36179400 DOI: 10.1016/j.ejmech.2022.114785] [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: 07/08/2022] [Revised: 09/16/2022] [Accepted: 09/16/2022] [Indexed: 11/29/2022]
Abstract
Kappa opioid receptor (KOR) is a member of the opioid receptor system, the G protein-coupled receptors that are expressed throughout the peripheral and central nervous systems and play crucial roles in the modulation of antinociception and a variety of behavioral states like anxiety, depression, and drug abuse. KOR agonists are known to produce potent analgesic effects and have been used clinically for the treatment of pain, while KOR antagonists have shown efficacy in the treatment of anxiety and depression. This review summarizes the history, design strategy, discovery, and development of KOR ligands. KOR agonists are classified as non-biased, G protein-biased, and β-arrestin recruitment-biased, according to their degrees of bias. The mechanisms and associated effects of the G protein signaling pathway and β-arrestin recruitment signaling pathway are also discussed. Meanwhile, KOR antagonists are classified as long-acting and short-acting, based on their half-lives. In addition, we have special sections for mixed KOR agonists and selective peripheral KOR agonists. The mechanisms of action and pharmacokinetic, pharmacodynamic, and behavioral studies for each of these categories are also discussed in this review.
Collapse
Affiliation(s)
- Md Imdadul H Khan
- Department of BioMolecular Sciences and Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, University, MS, 38677, USA
| | - Benjamin J Sawyer
- Department of BioMolecular Sciences and Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, University, MS, 38677, USA
| | - Nicholas S Akins
- Department of BioMolecular Sciences and Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, University, MS, 38677, USA
| | - Hoang V Le
- Department of BioMolecular Sciences and Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, University, MS, 38677, USA.
| |
Collapse
|
8
|
Paul B, Sribhashyam S, Majumdar S. Opioid signaling and design of analgesics. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 195:153-176. [PMID: 36707153 PMCID: PMC10325139 DOI: 10.1016/bs.pmbts.2022.06.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Clinical treatment of acute to severe pain relies on the use of opioids. While their potency is significant, there are considerable side effects that can negatively affect patients. Their rise in usage has correlated with the current opioid epidemic in the United States, which has led to more than 70,000 deaths per year (Volkow and Blanco, 2021). Opioid-related drug development aims to make target compounds that show strong potency but with diminished side effects. Research into pharmaceuticals that could act as potential alternatives to current pains medications has relied on mechanistic insights of opioid receptors, a class of G-protein coupled receptors (GPCRs), and biased agonism, a common phenomenon among pharmaceutical compounds where downstream effects can be altered at the same receptor via different agonists. Opioids function typically by binding to an active site on the extracellular portion of opioid receptors. Once activated, the opioid receptor initiates a G-protein signaling pathway and/or the β-arrestin2 pathway. The proposed concept for the development of safe analgesics around mu and kappa opioid receptor subtypes has focused on not recruiting β-arrestin2 (biased agonism) and/or having low efficacy at the receptor (partial agonism). By altering chemical motifs on a common scaffold, chemists can take advantage of biased agonism as well as create compounds with low intrinsic efficacy for the desired treatments. This review will focus on ligands with bias profile, signaling aspects of the receptor and probe into the structural basis of receptor that leads to bias and/or partial agonism.
Collapse
Affiliation(s)
- Barnali Paul
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St Louis and Washington University School of Medicine, St Louis, MO, United States
| | - Sashrik Sribhashyam
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St Louis and Washington University School of Medicine, St Louis, MO, United States
| | - Susruta Majumdar
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St Louis and Washington University School of Medicine, St Louis, MO, United States.
| |
Collapse
|
9
|
French AR, van Rijn RM. An updated assessment of the translational promise of G-protein-biased kappa opioid receptor agonists to treat pain and other indications without debilitating adverse effects. Pharmacol Res 2022; 177:106091. [PMID: 35101565 PMCID: PMC8923989 DOI: 10.1016/j.phrs.2022.106091] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 01/22/2023]
Abstract
Kappa opioid receptor (κOR) agonists lack the abuse liability and respiratory depression effects of clinically used mu opioid receptor (μOR) analgesics and are hypothesized to be safer alternatives. However, κOR agonists have limiting adverse effects of their own, including aversion, sedation, and mood effects, that have hampered their clinical translation. Studies performed over the last 15 years have suggested that these adverse effects could result from activation of distinct intracellular signaling pathways that are dependent on β-arrestin, whereas signaling downstream of G protein activation produces antinociception. This led to the hypothesis that agonists biased away from β-arrestin signaling would have improved therapeutic windows over traditional unbiased agonists and allow for clinical development of analgesic G-protein-biased κOR agonists. Given a recent controversy regarding the benefits of G-protein-biased μOR agonists, it is timely to reassess the therapeutic promise of G-protein-biased κOR agonists. Here we review recent discoveries from preclinical κOR studies and critically evaluate the therapeutic windows of G-protein-biased κOR agonists in each of the adverse effects above. Overall, we find that G-protein-biased κOR agonists generally have improved therapeutic window relative to unbiased agonists, although frequently study design limits strong conclusions in this regard. However, a steady flow of newly developed biased κOR agonists paired with recently engineered behavioral and molecular tools puts the κOR field in a prime position to make major advances in our understanding of κOR function and fulfill the promise of translating a new generation of biased κOR agonists to the clinic.
Collapse
Affiliation(s)
- Alexander R French
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Richard M van Rijn
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA.
| |
Collapse
|
10
|
Abstract
Temporal lobe epilepsy is considered to be one of the most common and severe forms of focal epilepsies. Patients frequently develop cognitive deficits and emotional blunting along progression of the disease. The high incidence of refractoriness to antiepileptic drugs and a frequent lack of admissibility to surgery pose an unmet medical challenge. In the urgent quest for novel treatment strategies, neuropeptides and their receptors are interesting candidates. However, their therapeutic potential has not yet been fully exploited. This chapter focuses on the functional role of the dynorphins (Dyns) and the kappa opioid receptor (KOR) system in temporal lobe epilepsy and the hippocampus.Genetic polymorphisms in the prepro-dynorphin (pDyn) gene causing lower levels of Dyns in humans and pDyn gene knockout in mice increase the risk to develop epilepsy. This suggests a role of Dyns and KOR as modulators of neuronal excitability. Indeed, KOR agonists induce inhibition of presynaptic neurotransmitter release, as well as postsynaptic hyperpolarization in glutamatergic neurons, both producing anticonvulsant effects.The development of new approaches to modulate the complex KOR signalling cascade (e.g. biased agonism and gene therapy) opens up new exciting therapeutic opportunities with regard to seizure control and epilepsy. Potential adverse side effects of KOR agonists may be minimized through functional selectivity or locally restricted treatment. Preclinical data suggest a high potential of such approaches to control seizures.
Collapse
Affiliation(s)
- Luca Zangrandi
- Institute of Virology, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Berlin, Germany
- Freie Universität Berlin, Berlin, Germany
- Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health, Berlin, Germany
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria.
| |
Collapse
|
11
|
Cowan A, Liu-Chen LY, Inan S. Itching-like behavior: A common effect of the kappa opioid receptor antagonist 5′-guanidinonaltrindole and the biased kappa opioid receptor agonist 6′-guanidinonaltrindole in mice. MEDICINE IN DRUG DISCOVERY 2021. [DOI: 10.1016/j.medidd.2021.100097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
|
12
|
Spetea M, Schmidhammer H. Kappa Opioid Receptor Ligands and Pharmacology: Diphenethylamines, a Class of Structurally Distinct, Selective Kappa Opioid Ligands. Handb Exp Pharmacol 2021; 271:163-195. [PMID: 33454858 DOI: 10.1007/164_2020_431] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The kappa opioid receptor (KOR), a G protein-coupled receptor, and its endogenous ligands, the dynorphins, are prominent members of the opioid neuromodulatory system. The endogenous kappa opioid system is expressed in the central and peripheral nervous systems, and has a key role in modulating pain in central and peripheral neuronal circuits and a wide array of physiological functions and neuropsychiatric behaviors (e.g., stress, reward, emotion, motivation, cognition, epileptic seizures, itch, and diuresis). We review the latest advances in pharmacology of the KOR, chemical developments on KOR ligands with advances and challenges, and therapeutic and potential applications of KOR ligands. Diverse discovery strategies of KOR ligands targeting natural, naturally derived, and synthetic compounds with different scaffolds, as small molecules or peptides, with short or long-acting pharmacokinetics, and central or peripheral site of action, are discussed. These research efforts led to ligands with distinct pharmacological properties, as agonists, partial agonists, biased agonists, and antagonists. Differential modulation of KOR signaling represents a promising strategy for developing pharmacotherapies for several human diseases, either by activating (treatment of pain, pruritus, and epilepsy) or blocking (treatment of depression, anxiety, and addiction) the receptor. We focus on the recent chemical and pharmacological advances on diphenethylamines, a new class of structurally distinct, selective KOR ligands. Design strategies and investigations to define structure-activity relationships together with in vivo pharmacology of diphenethylamines as agonists, biased agonists, and antagonists and their potential use as therapeutics are discussed.
Collapse
Affiliation(s)
- Mariana Spetea
- Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria.
| | - Helmut Schmidhammer
- Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
| |
Collapse
|
13
|
Schmidhammer H, Erli F, Guerrieri E, Spetea M. Development of Diphenethylamines as Selective Kappa Opioid Receptor Ligands and Their Pharmacological Activities. Molecules 2020; 25:molecules25215092. [PMID: 33147885 PMCID: PMC7663249 DOI: 10.3390/molecules25215092] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 02/01/2023] Open
Abstract
Among the opioid receptors, the kappa opioid receptor (KOR) has been gaining substantial attention as a promising molecular target for the treatment of numerous human disorders, including pain, pruritus, affective disorders (i.e., depression and anxiety), drug addiction, and neurological diseases (i.e., epilepsy). Particularly, the knowledge that activation of the KOR, opposite to the mu opioid receptor (MOR), does not produce euphoria or leads to respiratory depression or overdose, has stimulated the interest in discovering ligands targeting the KOR as novel pharmacotherapeutics. However, the KOR mediates the negative side effects of dysphoria/aversion, sedation, and psychotomimesis, with the therapeutic promise of biased agonism (i.e., selective activation of beneficial over deleterious signaling pathways) for designing safer KOR therapeutics without the liabilities of conventional KOR agonists. In this review, the development of new KOR ligands from the class of diphenethylamines is presented. Specifically, we describe the design strategies, synthesis, and pharmacological activities of differently substituted diphenethylamines, where structure–activity relationships have been extensively studied. Ligands with distinct profiles as potent and selective agonists, G protein-biased agonists, and selective antagonists, and their potential use as therapeutic agents (i.e., pain treatment) and research tools are described.
Collapse
MESH Headings
- Analgesics, Opioid/chemistry
- Analgesics, Opioid/therapeutic use
- Humans
- Ligands
- Pain/drug therapy
- Pain/metabolism
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/chemistry
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/chemistry
- Receptors, Opioid, mu/metabolism
- Structure-Activity Relationship
Collapse
|
14
|
Faouzi A, Varga BR, Majumdar S. Biased Opioid Ligands. Molecules 2020; 25:E4257. [PMID: 32948048 PMCID: PMC7570672 DOI: 10.3390/molecules25184257] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/11/2020] [Accepted: 09/12/2020] [Indexed: 12/12/2022] Open
Abstract
Achieving effective pain management is one of the major challenges associated with modern day medicine. Opioids, such as morphine, have been the reference treatment for moderate to severe acute pain not excluding chronic pain modalities. Opioids act through the opioid receptors, the family of G-protein coupled receptors (GPCRs) that mediate pain relief through both the central and peripheral nervous systems. Four types of opioid receptors have been described, including the μ-opioid receptor (MOR), κ-opioid receptor (KOR), δ-opioid receptor (DOR), and the nociceptin opioid peptide receptor (NOP receptor). Despite the proven success of opioids in treating pain, there are still some inherent limitations. All clinically approved MOR analgesics are associated with adverse effects, which include tolerance, dependence, addiction, constipation, and respiratory depression. On the other hand, KOR selective analgesics have found limited clinical utility because they cause sedation, anxiety, dysphoria, and hallucinations. DOR agonists have also been investigated but they have a tendency to cause convulsions. Ligands targeting NOP receptor have been reported in the preclinical literature to be useful as spinal analgesics and as entities against substance abuse disorders while mixed MOR/NOP receptor agonists are useful as analgesics. Ultimately, the goal of opioid-related drug development has always been to design and synthesize derivatives that are equally or more potent than morphine but most importantly are devoid of the dangerous residual side effects and abuse potential. One proposed strategy is to take advantage of biased agonism, in which distinct downstream pathways can be activated by different molecules working through the exact same receptor. It has been proposed that ligands not recruiting β-arrestin 2 or showing a preference for activating a specific G-protein mediated signal transduction pathway will function as safer analgesic across all opioid subtypes. This review will focus on the design and the pharmacological outcomes of biased ligands at the opioid receptors, aiming at achieving functional selectivity.
Collapse
MESH Headings
- Analgesics, Opioid/chemistry
- Analgesics, Opioid/metabolism
- Analgesics, Opioid/pharmacology
- Analgesics, Opioid/therapeutic use
- Arrestin/metabolism
- Furans/chemistry
- Furans/metabolism
- Humans
- Ligands
- Pain/drug therapy
- Pyrones/chemistry
- Pyrones/metabolism
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/metabolism
- Signal Transduction/drug effects
Collapse
Affiliation(s)
| | | | - Susruta Majumdar
- Center for Clinical Pharmacology, St. Louis College of Pharmacy and Washington University School of Medicine, St. Louis, MO 63131, USA; (A.F.); (B.R.V.)
| |
Collapse
|
15
|
Paton KF, Atigari DV, Kaska S, Prisinzano T, Kivell BM. Strategies for Developing κ Opioid Receptor Agonists for the Treatment of Pain with Fewer Side Effects. J Pharmacol Exp Ther 2020; 375:332-348. [PMID: 32913006 DOI: 10.1124/jpet.120.000134] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/27/2020] [Indexed: 12/21/2022] Open
Abstract
There is significant need to find effective, nonaddictive pain medications. κ Opioid receptor (KOPr) agonists have been studied for decades but have recently received increased attention because of their analgesic effects and lack of abuse potential. However, a range of side effects have limited the clinical development of these drugs. There are several strategies currently used to develop safer and more effective KOPr agonists. These strategies include identifying G-protein-biased agonists, developing peripherally restricted KOPr agonists without centrally mediated side effects, and developing mixed opioid agonists, which target multiple receptors at specific ratios to balance side-effect profiles and reduce tolerance. Here, we review the latest developments in research related to KOPr agonists for the treatment of pain. SIGNIFICANCE STATEMENT: This review discusses strategies for developing safer κ opioid receptor (KOPr) agonists with therapeutic potential for the treatment of pain. Although one strategy is to modify selective KOPr agonists to create peripherally restricted or G-protein-biased structures, another approach is to combine KOPr agonists with μ, δ, or nociceptin opioid receptor activation to obtain mixed opioid receptor agonists, therefore negating the adverse effects and retaining the therapeutic effect.
Collapse
Affiliation(s)
- Kelly F Paton
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand (K.P., D.V.A., B.M.K.) and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky (S.K., T.P.)
| | - Diana V Atigari
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand (K.P., D.V.A., B.M.K.) and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky (S.K., T.P.)
| | - Sophia Kaska
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand (K.P., D.V.A., B.M.K.) and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky (S.K., T.P.)
| | - Thomas Prisinzano
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand (K.P., D.V.A., B.M.K.) and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky (S.K., T.P.)
| | - Bronwyn M Kivell
- School of Biological Sciences, Centre for Biodiscovery, Victoria University of Wellington, Wellington, New Zealand (K.P., D.V.A., B.M.K.) and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky (S.K., T.P.)
| |
Collapse
|
16
|
Paton KF, Biggerstaff A, Kaska S, Crowley RS, La Flamme AC, Prisinzano TE, Kivell BM. Evaluation of Biased and Balanced Salvinorin A Analogs in Preclinical Models of Pain. Front Neurosci 2020; 14:765. [PMID: 32792903 PMCID: PMC7385413 DOI: 10.3389/fnins.2020.00765] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 06/29/2020] [Indexed: 01/09/2023] Open
Abstract
In the search for safer, non-addictive analgesics, kappa opioid receptor (KOPr) agonists are a potential target, as unlike mu-opioid analgesics, they do not have abuse potential. Salvinorin A (SalA) is a potent and selective KOPr agonist, however, clinical utility is limited by the short duration of action and aversive side effects. Biasing KOPr signaling toward G-protein activation has been highlighted as a key cellular mechanism to reduce the side effects of KOPr agonists. The present study investigated KOPr signaling bias and the acute antinociceptive effects and side effects of two novel analogs of SalA, 16-Bromo SalA and 16-Ethynyl SalA. 16-Bromo SalA showed G-protein signaling bias, whereas 16-Ethynyl SalA displayed balanced signaling properties. In the dose-response tail-withdrawal assay, SalA, 16-Ethynyl SalA and 16-Bromo SalA were more potent than the traditional KOPr agonist U50,488, and 16-Ethynyl SalA was more efficacious. 16-Ethynyl SalA and 16-Bromo SalA both had a longer duration of action in the warm water tail-withdrawal assay, and 16-Ethynyl had greater antinociceptive effect in the hot-plate assay, compared to SalA. In the intraplantar 2% formaldehyde test, 16-Ethynyl SalA and 16-Bromo SalA significantly reduced both nociceptive and inflammatory pain-related behaviors. Moreover, 16-Ethynyl SalA and 16-Bromo SalA had no anxiogenic effects in the marble burying task, and 16-Bromo SalA did not alter behavior in the elevated zero maze. Overall, 16-Ethynyl SalA significantly attenuated acute pain-related behaviors in multiple preclinical models, while the biased KOPr agonist, 16-Bromo SalA, displayed modest antinociceptive effects, and lacked anxiogenic effects.
Collapse
Affiliation(s)
- Kelly F Paton
- School of Biological Sciences, Centre for Biodiscovery, Faculty of Science, Victoria University of Wellington, Wellington, New Zealand
| | - Andrew Biggerstaff
- School of Biological Sciences, Centre for Biodiscovery, Faculty of Science, Victoria University of Wellington, Wellington, New Zealand
| | - Sophia Kaska
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, United States
| | - Rachel S Crowley
- Department of Medicinal Chemistry, School of Pharmacy, The University of Kansas, Lawrence, KS, United States
| | - Anne C La Flamme
- School of Biological Sciences, Centre for Biodiscovery, Faculty of Science, Victoria University of Wellington, Wellington, New Zealand.,Malaghan Institute of Medical Research, Wellington, New Zealand
| | - Thomas E Prisinzano
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, United States.,Department of Medicinal Chemistry, School of Pharmacy, The University of Kansas, Lawrence, KS, United States
| | - Bronwyn M Kivell
- School of Biological Sciences, Centre for Biodiscovery, Faculty of Science, Victoria University of Wellington, Wellington, New Zealand
| |
Collapse
|
17
|
Bulleyaconitine A Inhibits Visceral Nociception and Spinal Synaptic Plasticity through Stimulation of Microglial Release of Dynorphin A. Neural Plast 2020; 2020:1484087. [PMID: 32565774 PMCID: PMC7262664 DOI: 10.1155/2020/1484087] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 02/14/2020] [Accepted: 03/11/2020] [Indexed: 12/20/2022] Open
Abstract
Background Visceral pain is one of the most common types of pain and particularly in the abdomen is associated with gastrointestinal diseases. Bulleyaconitine A (BAA), isolated from Aconitum bulleyanum, is prescribed in China to treat chronic pain. The present study is aimed at evaluating the mechanisms underlying BAA visceral antinociception. Methods The rat model of chronic visceral hypersensitivity was set up by colonic perfusion of 2,4,6-trinitrobenzene sulfonic acid (TNBS) on postnatal day 10 with coapplication of heterotypic intermittent chronic stress (HeICS). Results The rat model of chronic visceral hypersensitivity exhibited remarkable abdominal withdrawal responses and mechanical hyperalgesia in hind paws, which were dose-dependently attenuated by single subcutaneous of administration of BAA (30 and 90 μg/kg). Pretreatment with the microglial inhibitor minocycline, dynorphin A antiserum, and κ-opioid receptor antagonist totally blocked BAA-induced visceral antinociception and mechanical antihyperalgesia. Spontaneous excitatory postsynaptic currents (sEPSCs) in spinal dorsal horn lamina II neurons were recorded by using whole-cell patch clamp. Its frequency (but not amplitude) from TNBS-treated rats was remarkably higher than that from naïve rats. BAA (1 μM) significantly reduced the frequency of sEPSCs from TNBS-treated rats but not naïve rats. BAA-inhibited spinal synaptic plasticity was blocked by minocycline, the dynorphin A antiserum, and κ-opioid receptor antagonist. Dynorphin A also inhibited spinal synaptic plasticity in a κ-opioid receptor-dependent manner. Conclusions These results suggest that BAA produces visceral antinociception by stimulating spinal microglial release of dynorphin A, which activates presynaptic κ-opioid receptors in afferent neurons and inhibits spinal synaptic plasticity, highlighting a novel interaction mode between microglia and neurons.
Collapse
|
18
|
Auer T, Schreppel P, Erker T, Schwarzer C. Functional characterization of novel bumetanide derivatives for epilepsy treatment. Neuropharmacology 2020; 162:107754. [PMID: 31476353 DOI: 10.1016/j.neuropharm.2019.107754] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 08/23/2019] [Accepted: 08/29/2019] [Indexed: 12/12/2022]
Abstract
Temporal lobe epilepsy (TLE) is the most common type of focal epilepsies, affecting approximately 35 million people worldwide. Despite the introduction of numerous novel antiepileptic drugs during the last decades, the proportion of patients with therapy-resistant TLE is still high. As an impaired cellular chloride homeostasis appears involved in disease pathophysiology, bumetanide, an antagonist to Na-K-Cl cotransporters, gained interest as potential therapeutic option. However, bumetanide induces a strong diuretic effect and displays poor penetration across the blood-brain barrier (BBB). To reduce these unwanted effects, we modified the already described BUM690 by exchanging the allyl-into a trifluoro-ethyl group to yield BUM532. Furthermore, we exchanged the nitrogen for oxygen in the trifluoro-ethyl group to yield BUM97. In the intrahippocampal kainic acid mouse model of TLE BUM532 ± phenobarbital (PB), bumetanide ± PB and PB alone significantly reduced hippocampal paroxysmal discharges (HPDs) but not spike trains. By contrast, treatment with BUM97 suppressed HPDs as well as spike trains dose-dependently, more pronounced compared to the other tested compounds and exerted a synergistic anticonvulsant effect with PB. Moreover, at higher doses BUM97 achieved long-lasting reduction of spike trains. In pentylenetetrazole-induced acute seizures only BUM532 combined with a sub-effective dose of PB increased the seizure threshold. No diuretic effects were observed at any dose of the three derivatives. Our data demonstrate the successful optimization of the pharmacological profile of bumetanide and the potential of the improved derivative BUM97 for the treatment of therapy-resistant TLE, in particular in combinatorial drug regimens with a GABA mimetic.
Collapse
Affiliation(s)
- Theresa Auer
- Department of Pharmacology, Medical University of Innsbruck, Peter-Mayr-Str. 1a, 6020, Innsbruck, Austria.
| | - Philipp Schreppel
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria.
| | - Thomas Erker
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria.
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of Innsbruck, Peter-Mayr-Str. 1a, 6020, Innsbruck, Austria.
| |
Collapse
|
19
|
Agostinho AS, Mietzsch M, Zangrandi L, Kmiec I, Mutti A, Kraus L, Fidzinski P, Schneider UC, Holtkamp M, Heilbronn R, Schwarzer C. Dynorphin-based "release on demand" gene therapy for drug-resistant temporal lobe epilepsy. EMBO Mol Med 2019; 11:e9963. [PMID: 31486590 PMCID: PMC6783645 DOI: 10.15252/emmm.201809963] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 08/01/2019] [Accepted: 08/06/2019] [Indexed: 11/13/2022] Open
Abstract
Focal epilepsy represents one of the most common chronic CNS diseases. The high incidence of drug resistance, devastating comorbidities, and insufficient responsiveness to surgery pose unmet medical challenges. In the quest of novel, disease-modifying treatment strategies of neuropeptides represent promising candidates. Here, we provide the "proof of concept" that gene therapy by adeno-associated virus (AAV) vector transduction of preprodynorphin into the epileptogenic focus of well-accepted mouse and rat models for temporal lobe epilepsy leads to suppression of seizures over months. The debilitating long-term decline of spatial learning and memory is prevented. In human hippocampal slices obtained from epilepsy surgery, dynorphins suppressed seizure-like activity, suggestive of a high potential for clinical translation. AAV-delivered preprodynorphin expression is focally and neuronally restricted and release is dependent on high-frequency stimulation, as it occurs at the onset of seizures. The novel format of "release on demand" dynorphin delivery is viewed as a key to prevent habituation and to minimize the risk of adverse effects, leading to long-term suppression of seizures and of their devastating sequel.
Collapse
Affiliation(s)
| | - Mario Mietzsch
- Institute of VirologyCampus Benjamin Franklin, Charité ‐ Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Luca Zangrandi
- Department of PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Iwona Kmiec
- Department of PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Anna Mutti
- Department of PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Larissa Kraus
- Department of NeurologyCharité ‐ Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of Health, Epilepsy‐Center Berlin‐BrandenburgBerlinGermany
- Berlin Institute of Health (BIH)BerlinGermany
| | - Pawel Fidzinski
- Department of NeurologyCharité ‐ Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of Health, Epilepsy‐Center Berlin‐BrandenburgBerlinGermany
| | - Ulf C Schneider
- Department of NeurosurgeryCharité ‐ Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Martin Holtkamp
- Department of NeurologyCharité ‐ Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of Health, Epilepsy‐Center Berlin‐BrandenburgBerlinGermany
- Berlin Institute of Health (BIH)BerlinGermany
| | - Regine Heilbronn
- Institute of VirologyCampus Benjamin Franklin, Charité ‐ Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
- Berlin Institute of Health (BIH)BerlinGermany
| | | |
Collapse
|
20
|
Mores KL, Cummins BR, Cassell RJ, van Rijn RM. A Review of the Therapeutic Potential of Recently Developed G Protein-Biased Kappa Agonists. Front Pharmacol 2019; 10:407. [PMID: 31057409 PMCID: PMC6478756 DOI: 10.3389/fphar.2019.00407] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/01/2019] [Indexed: 01/22/2023] Open
Abstract
Between 2000 and 2005 several studies revealed that morphine is more potent and exhibits fewer side effects in beta-arrestin 2 knockout mice. These findings spurred efforts to develop opioids that signal primarily via G protein activation and do not, or only very weakly, recruit beta-arrestin. Development of such molecules targeting the mu opioid receptor initially outpaced those targeting the kappa, delta and nociceptin opioid receptors, with the G protein-biased mu opioid agonist oliceridine/TRV130 having completed phase III clinical trials with improved therapeutic window to treat moderate-to-severe acute pain. Recently however, there has been a sharp increase in the development of novel G protein-biased kappa agonists. It is hypothesized that G protein-biased kappa agonists can reduce pain and itch, but exhibit fewer side effects, such as anhedonia and psychosis, that have thus far limited the clinical development of unbiased kappa opioid agonists. Here we summarize recently discovered G protein-biased kappa agonists, comparing structures, degree of signal bias and preclinical effects. We specifically reviewed nalfurafine, 22-thiocyanatosalvinorin A (RB-64), mesyl-salvinorin B, 2-(4-(furan-2-ylmethyl)-5-((4-methyl-3-(trifluoromethyl)benzyl)thio)-4H-1,2,4-triazol-3-yl)pyridine (triazole 1.1), 3-(2-((cyclopropylmethyl)(phenethyl)amino)ethyl)phenol (HS666), N-n-butyl-N-phenylethyl-N-3-hydroxyphenylethyl-amine (compound 5/BPHA), 6-guanidinonaltrindole (6′GNTI), and collybolide. These agonists encompass a variety of chemical scaffolds and range in both their potency and efficacy in terms of G protein signaling and beta-arrestin recruitment. Thus unsurprisingly, the behavioral responses reported for these agonists are not uniform. Yet, it is our conclusion that the kappa opioid field will benefit tremendously from future studies that compare several biased agonists and correlate the degree of signaling bias to a particular pharmacological response.
Collapse
Affiliation(s)
- Kendall L Mores
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, West Lafayette, IN, United States
| | - Benjamin R Cummins
- Department of Chemistry, College of Science, West Lafayette, IN, United States
| | - Robert J Cassell
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, West Lafayette, IN, United States.,Purdue Institute for Drug Discovery, West Lafayette, IN, United States
| | - Richard M van Rijn
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, West Lafayette, IN, United States.,Purdue Institute for Drug Discovery, West Lafayette, IN, United States.,Purdue Institute for Integrative Neuroscience, West Lafayette, IN, United States
| |
Collapse
|
21
|
Liu JJ, Sharma K, Zangrandi L, Chen C, Humphrey SJ, Chiu YT, Spetea M, Liu-Chen LY, Schwarzer C, Mann M. In vivo brain GPCR signaling elucidated by phosphoproteomics. Science 2018; 360:360/6395/eaao4927. [PMID: 29930108 DOI: 10.1126/science.aao4927] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 04/27/2018] [Indexed: 12/12/2022]
Abstract
A systems view of G protein-coupled receptor (GPCR) signaling in its native environment is central to the development of GPCR therapeutics with fewer side effects. Using the kappa opioid receptor (KOR) as a model, we employed high-throughput phosphoproteomics to investigate signaling induced by structurally diverse agonists in five mouse brain regions. Quantification of 50,000 different phosphosites provided a systems view of KOR in vivo signaling, revealing novel mechanisms of drug action. Thus, we discovered enrichment of the mechanistic target of rapamycin (mTOR) pathway by U-50,488H, an agonist causing aversion, which is a typical KOR-mediated side effect. Consequently, mTOR inhibition during KOR activation abolished aversion while preserving beneficial antinociceptive and anticonvulsant effects. Our results establish high-throughput phosphoproteomics as a general strategy to investigate GPCR in vivo signaling, enabling prediction and modulation of behavioral outcomes.
Collapse
Affiliation(s)
- Jeffrey J Liu
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Kirti Sharma
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Luca Zangrandi
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Chongguang Chen
- Center for Substance Abuse Research and Department of Pharmacology, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA
| | - Sean J Humphrey
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Yi-Ting Chiu
- Center for Substance Abuse Research and Department of Pharmacology, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA
| | - Mariana Spetea
- Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Lee-Yuan Liu-Chen
- Center for Substance Abuse Research and Department of Pharmacology, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria.
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. .,Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| |
Collapse
|
22
|
Ho JH, Stahl EL, Schmid CL, Scarry SM, Aubé J, Bohn LM. G protein signaling-biased agonism at the κ-opioid receptor is maintained in striatal neurons. Sci Signal 2018; 11:11/542/eaar4309. [PMID: 30087177 DOI: 10.1126/scisignal.aar4309] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Biased agonists of G protein-coupled receptors may present a means to refine receptor signaling in a way that separates side effects from therapeutic properties. Several studies have shown that agonists that activate the κ-opioid receptor (KOR) in a manner that favors G protein coupling over β-arrestin2 recruitment in cell culture may represent a means to treat pain and itch while avoiding sedation and dysphoria. Although it is attractive to speculate that the bias between G protein signaling and β-arrestin2 recruitment is the reason for these divergent behaviors, little evidence has emerged to show that these signaling pathways diverge in the neuronal environment. We further explored the influence of cellular context on biased agonism at KOR ligand-directed signaling toward G protein pathways over β-arrestin-dependent pathways and found that this bias persists in striatal neurons. These findings advance our understanding of how a G protein-biased agonist signal differs between cell lines and primary neurons, demonstrate that measuring [35S]GTPγS binding and the regulation of adenylyl cyclase activity are not necessarily orthogonal assays in cell lines, and emphasize the contributions of the environment to assessing biased agonism.
Collapse
Affiliation(s)
- Jo-Hao Ho
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Edward L Stahl
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Cullen L Schmid
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Sarah M Scarry
- UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jeffrey Aubé
- UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Laura M Bohn
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
| |
Collapse
|
23
|
Burtscher J, Schwarzer C. The Opioid System in Temporal Lobe Epilepsy: Functional Role and Therapeutic Potential. Front Mol Neurosci 2017; 10:245. [PMID: 28824375 PMCID: PMC5545604 DOI: 10.3389/fnmol.2017.00245] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/24/2017] [Indexed: 12/13/2022] Open
Abstract
Temporal lobe epilepsy is considered to be one of the most common and severe forms of focal epilepsies. Patients often develop cognitive deficits and emotional blunting along the progression of the disease. The high incidence of resistance to antiepileptic drugs and a frequent lack of admissibility to surgery poses an unmet medical challenge. In the urgent quest of novel treatment strategies, neuropeptides are interesting candidates, however, their therapeutic potential has not yet been exploited. This review focuses on the functional role of the endogenous opioid system with respect to temporal lobe epilepsy, specifically in the hippocampus. The role of dynorphins and kappa opioid receptors (KOPr) as modulators of neuronal excitability is well understood: both the reduced release of glutamate as well of postsynaptic hyperpolarization were shown in glutamatergic neurons. In line with this, low levels of dynorphin in humans and mice increase the risk of epilepsy development. The role of enkephalins is not understood so well. On one hand, some agonists of the delta opioid receptors (DOPr) display pro-convulsant properties probably through inhibition of GABAergic interneurons. On the other hand, enkephalins play a neuro-protective role under hypoxic or anoxic conditions, most probably through positive effects on mitochondrial function. Despite the supposed absence of endorphins in the hippocampus, exogenous activation of the mu opioid receptors (MOPr) induces pro-convulsant effects. Recently-expanded knowledge of the complex ways opioid receptors ligands elicit their effects (including biased agonism, mixed binding, and opioid receptor heteromers), opens up exciting new therapeutic potentials with regards to seizures and epilepsy. Potential adverse side effects of KOPr agonists may be minimized through functional selectivity. Preclinical data suggest a high potential of such compounds to control seizures, with a strong predictive validity toward human patients. The discovery of DOPr-agonists without proconvulsant potential stimulates the research on the therapeutic use of neuroprotective potential of the enkephalin/DOPr system.
Collapse
Affiliation(s)
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of InnsbruckInnsbruck, Austria
| |
Collapse
|
24
|
Spetea M, Eans SO, Ganno ML, Lantero A, Mairegger M, Toll L, Schmidhammer H, McLaughlin JP. Selective κ receptor partial agonist HS666 produces potent antinociception without inducing aversion after i.c.v. administration in mice. Br J Pharmacol 2017; 174:2444-2456. [PMID: 28494108 PMCID: PMC5513865 DOI: 10.1111/bph.13854] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/09/2017] [Accepted: 05/03/2017] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND AND PURPOSE The κ receptor has a central role in modulating neurotransmission in central and peripheral neuronal circuits that subserve pain and other behavioural responses. Although κ receptor agonists do not produce euphoria or lead to respiratory suppression, they induce dysphoria and sedation. We hypothesized that brain-penetrant κ receptor ligands possessing biased agonism towards G protein signalling over β-arrestin2 recruitment would produce robust antinociception with fewer associated liabilities. EXPERIMENTAL APPROACH Two new diphenethylamines with high κ receptor selectivity, HS665 and HS666, were assessed following i.c.v. administration in mouse assays of antinociception with the 55°C warm-water tail withdrawal test, locomotor activity in the rotorod and conditioned place preference. The [35 S]-GTPγS binding and β-arrestin2 recruitment in vitro assays were used to characterize biased agonism. KEY RESULTS HS665 (κ receptor agonist) and HS666 (κ receptor partial agonist) demonstrated dose-dependent antinociception after i.c.v. administration mediated by the κ receptor. These highly selective κ receptor ligands displayed varying biased signalling towards G protein coupling in vitro, consistent with a reduced liability profile, reflected by reduced sedation and absence of conditioned place aversion for HS666. CONCLUSIONS AND IMPLICATIONS HS665 and HS666 activate central κ receptors to produce potent antinociception, with HS666 displaying pharmacological characteristics of a κ receptor analgesic with reduced liability for aversive effects correlating with its low efficacy in the β-arrestin2 signalling pathway. Our data provide further understanding of the contribution of central κ receptors in pain suppression, and the prospect of dissociating the antinociceptive effects of HS665 and HS666 from κ receptor-mediated adverse effects.
Collapse
Affiliation(s)
- Mariana Spetea
- Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI)University of InnsbruckInnsbruckAustria
- Torrey Pines Institute for Molecular StudiesPort St. LucieFLUSA
| | - Shainnel O Eans
- Torrey Pines Institute for Molecular StudiesPort St. LucieFLUSA
- Department of PharmacodynamicsUniversity of FloridaGainesvilleFLUSA
| | | | - Aquilino Lantero
- Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI)University of InnsbruckInnsbruckAustria
| | - Michael Mairegger
- Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI)University of InnsbruckInnsbruckAustria
| | - Lawrence Toll
- Torrey Pines Institute for Molecular StudiesPort St. LucieFLUSA
| | - Helmut Schmidhammer
- Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI)University of InnsbruckInnsbruckAustria
| | - Jay P McLaughlin
- Torrey Pines Institute for Molecular StudiesPort St. LucieFLUSA
- Department of PharmacodynamicsUniversity of FloridaGainesvilleFLUSA
| |
Collapse
|
25
|
Madariaga-Mazón A, Marmolejo-Valencia AF, Li Y, Toll L, Houghten RA, Martinez-Mayorga K. Mu-Opioid receptor biased ligands: A safer and painless discovery of analgesics? Drug Discov Today 2017; 22:1719-1729. [PMID: 28743488 DOI: 10.1016/j.drudis.2017.07.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/24/2017] [Accepted: 07/07/2017] [Indexed: 12/19/2022]
Abstract
Biased activation of G-protein-coupled receptors (GPCRs) is shifting drug discovery efforts and appears promising for the development of safer drugs. The most effective analgesics to treat acute pain are agonists of the μ opioid receptor (μ-OR), a member of the GPCR superfamily. However, the analgesic use of opioid drugs, such as morphine, is hindered by adverse effects. Only a few μ-OR agonists have been reported to selectively activate the Gi over β-arrestin signaling pathway, resulting in lower gastrointestinal dysfunction and respiratory suppression. Here, we discuss the strategies that led to the development of biased μ-OR agonists, and potential areas for improvement, with an emphasis on structural aspects of the ligand-receptor recognition process.
Collapse
Affiliation(s)
- Abraham Madariaga-Mazón
- Instituto de Química, Universidad Nacional Autónoma de México, Av. Universidad 3000, Mexico City 04510, Mexico
| | - Andrés F Marmolejo-Valencia
- Instituto de Química, Universidad Nacional Autónoma de México, Av. Universidad 3000, Mexico City 04510, Mexico
| | - Yangmei Li
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Pkwy, Port St. Lucie, FL 34987, USA
| | - Lawrence Toll
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Pkwy, Port St. Lucie, FL 34987, USA
| | - Richard A Houghten
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Pkwy, Port St. Lucie, FL 34987, USA
| | - Karina Martinez-Mayorga
- Instituto de Química, Universidad Nacional Autónoma de México, Av. Universidad 3000, Mexico City 04510, Mexico.
| |
Collapse
|
26
|
Zangrandi L, Burtscher J, MacKay JP, Colmers WF, Schwarzer C. The G-protein biased partial κ opioid receptor agonist 6'-GNTI blocks hippocampal paroxysmal discharges without inducing aversion. Br J Pharmacol 2016; 173:1756-67. [PMID: 26928671 PMCID: PMC4867738 DOI: 10.1111/bph.13474] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 02/05/2016] [Accepted: 02/09/2016] [Indexed: 11/29/2022] Open
Abstract
Background and Purpose With a prevalence of 1–2%, epilepsies belong to the most frequent neurological diseases worldwide. Although antiepileptic drugs are available since several decades, the incidence of patients that are refractory to medication is still over 30%. Antiepileptic effects of κ opioid receptor (κ receptor) agonists have been proposed since the 1980s. However, their clinical use was hampered by dysphoric side effects. Recently, G‐protein biased κ receptor agonists were developed, suggesting reduced aversive effects. Experimental Approach We investigated the effects of the κ receptor agonist U‐50488H and the G‐protein biased partial κ receptor agonist 6′‐GNTI in models of acute seizures and drug‐resistant temporal lobe epilepsy and in the conditioned place avoidance (CPA) test. Moreover, we performed slice electrophysiology to understand the functional mechanisms of 6′‐GNTI. Key Results As previously shown for U‐50488H, 6′‐GNTI markedly increased the threshold for pentylenetetrazole‐induced seizures. All treated mice displayed reduced paroxysmal activity in response to U‐50488H (20 mg·kg−1) or 6′‐GNTI (10–30 nmoles) treatment in the mouse model of intra‐hippocampal injection of kainic acid. Single cell recordings on hippocampal pyramidal cells revealed enhanced inhibitory signalling as potential mechanisms causing the reduction of paroxysmal activity. Effects of 6′‐GNTI were blocked in both seizure models by the κ receptor antagonist 5′‐GNTI. Moreover, 6′‐GNTI did not induce CPA, a measure of aversive effects, while U‐50488H did. Conclusions and Implications Our data provide the proof of principle that anticonvulsant/antiseizure and aversive effects of κ receptor activation can be pharmacologically separated in vivo.
Collapse
Affiliation(s)
- Luca Zangrandi
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Johannes Burtscher
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - James P MacKay
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - William F Colmers
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| |
Collapse
|