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Scherrer KH, Eans SO, Medina JM, Senadheera SN, Khaliq T, Murray TF, McLaughlin JP, Aldrich JV. Tryptophan Substitution in CJ-15,208 ( cyclo[Phe-D-Pro-Phe-Trp]) Introduces δ-Opioid Receptor Antagonism, Preventing Antinociceptive Tolerance and Stress-Induced Reinstatement of Extinguished Cocaine-Conditioned Place Preference. Pharmaceuticals (Basel) 2023; 16:1218. [PMID: 37765026 PMCID: PMC10535824 DOI: 10.3390/ph16091218] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/11/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023] Open
Abstract
The macrocyclic tetrapeptide CJ-15,208 (cyclo[Phe-D-Pro-Phe-Trp]) and its D-Trp isomer exhibit kappa opioid receptor (KOR) antagonism which prevents stress-induced reinstatement of extinguished cocaine-conditioned place preference. Here, we evaluated the effects of substitution of Trp and D-Trp on the peptides' opioid activity, antinociceptive tolerance, and the ability to prevent relapse to extinguished drug-CPP. Six analogs were synthesized using a combination of solid-phase peptide synthesis and cyclization in solution. The analogs were evaluated in vitro for opioid receptor affinity in radioligand competition binding assays, efficacy in the [35S]GTPγS assay, metabolic stability in mouse liver microsomes, and for opioid activity and selectivity in vivo in the mouse 55 °C warm-water tail-withdrawal assay. Potential liabilities of locomotor impairment, respiratory depression, acute tolerance, and conditioned place preference (CPP) were also assessed in vivo, and the ameliorating effect of analogs on the reinstatement of extinguished cocaine-place preference was assessed. Substitutions of other D-amino acids for D-Trp did not affect (or in one case increased) KOR affinity, while two of the three substitutions of an L-amino acid for Trp decreased KOR affinity. In contrast, all but one substitution increased mu opioid receptor (MOR) affinity in vitro. The metabolic stabilities of the analogs were similar to those of their respective parent peptides, with analogs containing a D-amino acid being much more rapidly metabolized than those containing an L-amino acid in this position. In vivo, CJ-15,208 analogs demonstrated antinociception, although potencies varied over an 80-fold range and the mediating opioid receptors differed by substitution. KOR antagonism was lost for all but the D-benzothienylalanine analog, and the 2'-naphthylalanine analog instead demonstrated significant delta opioid receptor (DOR) antagonism. Introduction of DOR antagonism coincided with reduced acute opioid antinociceptive tolerance and prevented stress-induced reinstatement of extinguished cocaine-CPP.
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Affiliation(s)
- Kristen H. Scherrer
- Department of Pharmacodynamics, The University of Florida, Gainesville, FL 32610, USA; (K.H.S.); (S.O.E.); (J.M.M.)
| | - Shainnel O. Eans
- Department of Pharmacodynamics, The University of Florida, Gainesville, FL 32610, USA; (K.H.S.); (S.O.E.); (J.M.M.)
| | - Jessica M. Medina
- Department of Pharmacodynamics, The University of Florida, Gainesville, FL 32610, USA; (K.H.S.); (S.O.E.); (J.M.M.)
| | - Sanjeewa N. Senadheera
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, KS 66045, USA; (S.N.S.); (T.K.)
| | - Tanvir Khaliq
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, KS 66045, USA; (S.N.S.); (T.K.)
- Department of Medicinal Chemistry, The University of Florida, Gainesville, FL 32610, USA
| | - Thomas F. Murray
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, NE 68178, USA;
| | - Jay P. McLaughlin
- Department of Pharmacodynamics, The University of Florida, Gainesville, FL 32610, USA; (K.H.S.); (S.O.E.); (J.M.M.)
| | - Jane V. Aldrich
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, KS 66045, USA; (S.N.S.); (T.K.)
- Department of Medicinal Chemistry, The University of Florida, Gainesville, FL 32610, USA
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2
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Mehrotra S, Pierce ML, Dravid SM, Murray TF. Stimulation of Neurite Outgrowth in Cerebrocortical Neurons by Sodium Channel Activator Brevetoxin-2 Requires Both N-Methyl-D-aspartate Receptor 2B (GluN2B) and p21 Protein (Cdc42/Rac)-Activated Kinase 1 (PAK1). Mar Drugs 2022; 20:md20090559. [PMID: 36135748 PMCID: PMC9504648 DOI: 10.3390/md20090559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/25/2022] [Accepted: 08/28/2022] [Indexed: 12/05/2022] Open
Abstract
N-methyl-D-aspartate (NMDA) receptors play a critical role in activity-dependent dendritic arborization, spinogenesis, and synapse formation by stimulating calcium-dependent signaling pathways. Previously, we have shown that brevetoxin 2 (PbTx-2), a voltage-gated sodium channel (VGSC) activator, produces a concentration-dependent increase in intracellular sodium [Na+]I and increases NMDA receptor (NMDAR) open probabilities and NMDA-induced calcium (Ca2+) influxes. The objective of this study is to elucidate the downstream signaling mechanisms by which the sodium channel activator PbTx-2 influences neuronal morphology in murine cerebrocortical neurons. PbTx-2 and NMDA triggered distinct Ca2+-influx pathways, both of which involved the NMDA receptor 2B (GluN2B). PbTx-2-induced neurite outgrowth in day in vitro 1 (DIV-1) neurons required the small Rho GTPase Rac1 and was inhibited by both a PAK1 inhibitor and a PAK1 siRNA. PbTx-2 exposure increased the phosphorylation of PAK1 at Thr-212. At DIV-5, PbTx-2 induced increases in dendritic protrusion density, p-cofilin levels, and F-actin throughout the dendritic arbor and soma. Moreover, PbTx-2 increased miniature excitatory post-synaptic currents (mEPSCs). These data suggest that the stimulation of neurite outgrowth, spinogenesis, and synapse formation produced by PbTx-2 are mediated by GluN2B and PAK1 signaling.
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Affiliation(s)
- Suneet Mehrotra
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
- Omeros, Seattle, WA 98119, USA
| | - Marsha L. Pierce
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
- Department of Pharmacology, College of Graduate Studies, Midwestern University, Downers Grove, IL 60515, USA
| | - Shashank M. Dravid
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Thomas F. Murray
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
- Correspondence: ; Tel.: +1-402-280-2319
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Mehrotra S, Pierce ML, Cao Z, Jabba SV, Gerwick WH, Murray TF. Antillatoxin-Stimulated Neurite Outgrowth Involves the Brain-Derived Neurotrophic Factor (BDNF) - Tropomyosin Related Kinase B (TrkB) Signaling Pathway. J Nat Prod 2022; 85:562-571. [PMID: 35239341 PMCID: PMC9245549 DOI: 10.1021/acs.jnatprod.1c01001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Voltage-gated sodium channel (VGSC) activators promote neurite outgrowth by augmenting intracellular Na+ concentration ([Na+]i) and upregulating N-methyl-d-aspartate receptor (NMDAR) function. NMDAR activation stimulates calcium (Ca2+) influx and increases brain-derived neurotrophic factor (BDNF) release and activation of tropomyosin receptor kinase B (TrkB) signaling. The BDNF-TrkB pathway has been implicated in activity-dependent neuronal development. We have previously shown that antillatoxin (ATX), a novel lipopeptide isolated from the cyanobacterium Moorea producens, is a VGSC activator that produces an elevation of [Na+]i. Here we address the effect of ATX on the synthesis and release of BDNF and determine the signaling mechanisms by which ATX enhances neurite outgrowth in immature cerebrocortical neurons. ATX treatment produced a concentration-dependent release of BDNF. Acute treatment with ATX also resulted in increased synthesis of BDNF. ATX stimulation of neurite outgrowth was prevented by pretreatment with a TrkB inhibitor or transfection with a dominant-negative Trk-B. The ATX activation of TrkB and Akt was blocked by both a NMDAR antagonist (MK-801) and a VGSC blocker (tetrodotoxin). These results suggest that VGSC activators such as the structurally novel ATX may represent a new pharmacological strategy to promote neuronal plasticity through a NMDAR-BDNF-TrkB-dependent mechanism.
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Affiliation(s)
- Suneet Mehrotra
- Omeros, 201 Elliott Ave. West, Seattle, Washington 98119, United States
| | - Marsha L Pierce
- Department of Pharmacology, College of Graduate Studies, Midwestern University, Downers Grove, Illinois 60515, United States
| | - Zhengyu Cao
- State Key Laboratory of Natural Medicines and Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| | - Sairam V Jabba
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina 27710, United States
| | - William H Gerwick
- Center for Marine Biotech and Biomedicine, Scripps Institute of Oceanography, University of California at San Diego, San Diego, California 92093-0212, United States
| | - Thomas F Murray
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, United States
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Zhao Y, Joshi AA, Aldrich JV, Murray TF. Quantification of kappa opioid receptor ligand potency, efficacy and desensitization using a real-time membrane potential assay. Biomed Pharmacother 2021; 143:112173. [PMID: 34536757 PMCID: PMC8516733 DOI: 10.1016/j.biopha.2021.112173] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/02/2021] [Accepted: 09/05/2021] [Indexed: 10/25/2022] Open
Abstract
We explored the utility of the real-time FLIPR Membrane Potential (FMP) assay as a method to assess kappa opioid receptor (KOR)-induced hyperpolarization. The FMP Blue dye was used to measure fluorescent signals reflecting changes in membrane potential in KOR expressing CHO (CHO-KOR) cells. Treatment of CHO-KOR cells with kappa agonists U50,488 or dynorphin [Dyn (1-13)NH2] produced rapid and concentration-dependent decreases in FMP Blue fluorescence reflecting membrane hyperpolarization. Both the nonselective opioid antagonist naloxone and the κ-selective antagonists nor-binaltorphimine (nor-BNI) and zyklophin produced rightward shifts in the U50,488 concentration-response curves, consistent with competitive antagonism of the KOR mediated response. The decrease in fluorescent emission produced by U50,488 was blocked by overnight pertussis toxin pretreatment, indicating the requirement for PTX-sensitive G proteins in the KOR mediated response. We directly compared the potency of U50,488 and Dyn (1-13)NH2 in the FMP and [35S]GTPγS binding assays, and found that both were approximately 10 times more potent in the cellular fluorescence assay. The maximum responses of both U50,488 and Dyn (1-13)NH2 declined following repeated additions, reflecting receptor desensitization. We assessed the efficacy and potency of structurally distinct KOR small molecule and peptide ligands. The FMP assay reliably detected both partial agonists and stereoselectivity. Using KOR-selective peptides with varying efficacies, we found that the FMP assay allowed high throughput quantification of peptide efficacy. These data demonstrate that the FMP assay is a sensitive method for assessing κ-opioid receptor induced hyperpolarization, and represents a useful approach for quantification of potency, efficacy and desensitization of KOR ligands.
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Affiliation(s)
- Yuanzi Zhao
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, USA
| | - Anand A Joshi
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS, USA.
| | - Jane V Aldrich
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS, USA; Department of Medicinal Chemistry, University of Florida, Gainesville, FL, USA
| | - Thomas F Murray
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, USA
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Gisemba SA, Ferracane MJ, Murray TF, Aldrich JV. Conformational Constraint between Aromatic Residue Side Chains in the "Message" Sequence of the Peptide Arodyn Using Ring Closing Metathesis Results in a Potent and Selective Kappa Opioid Receptor Antagonist. J Med Chem 2021; 64:3153-3164. [PMID: 33688737 DOI: 10.1021/acs.jmedchem.0c01984] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Kappa opioid receptor (KOR) antagonists have recently shown potential for treating drug addiction and mood disorders. The linear acetylated dynorphin A analog arodyn (Ac[Phe1,2,3,Arg4,d-Ala8]dynorphin A-(1-11)NH2), synthesized in our laboratory, demonstrated potent and selective KOR antagonism. Cyclization of arodyn could potentially stabilize the bioactive conformation and enhance its metabolic stability. The cyclization strategy employed involved ring closing metathesis between adjacent meta- or para-substituted Tyr(allyl) residues in the "message" sequence that were predicted in a docking study to yield analogs that would bind to the KOR with binding poses similar to arodyn. Consistent with the modeling, the resulting analogs retained KOR affinity similar to arodyn; the peptides involving cyclization between para O-allyl groups also retained high KOR selectivity, with one analog exhibiting KOR antagonist potency (KB = 15 nM) similar to arodyn. These promising cyclized analogs with constrained aromatic residues represent novel leads for further exploration of KOR pharmacology.
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Affiliation(s)
- Solomon A Gisemba
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, United States.,Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
| | - Michael J Ferracane
- Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States.,Department of Chemistry, University of Redlands, Redlands, California 92373, United States
| | - Thomas F Murray
- Departments of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, Nebraska 68102, United States
| | - Jane V Aldrich
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, United States.,Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610, United States
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Brice-Tutt AC, Senadheera SN, Ganno ML, Eans SO, Khaliq T, Murray TF, McLaughlin JP, Aldrich JV. Phenylalanine Stereoisomers of CJ-15,208 and [d-Trp]CJ-15,208 Exhibit Distinctly Different Opioid Activity Profiles. Molecules 2020; 25:molecules25173999. [PMID: 32887303 PMCID: PMC7504817 DOI: 10.3390/molecules25173999] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 07/31/2020] [Revised: 08/30/2020] [Accepted: 08/31/2020] [Indexed: 02/06/2023] Open
Abstract
The macrocyclic tetrapeptide cyclo[Phe-d-Pro-Phe-Trp] (CJ-15,208) and its stereoisomer cyclo[Phe-d-Pro-Phe-d-Trp] exhibit different opioid activity profiles in vivo. The present study evaluated the influence of the Phe residues’ stereochemistry on the peptides’ opioid activity. Five stereoisomers were synthesized by a combination of solid-phase peptide synthesis and cyclization in solution. The analogs were evaluated in vitro for opioid receptor affinity in radioligand competition binding assays, and for opioid activity and selectivity in vivo in the mouse 55 °C warm-water tail-withdrawal assay. Potential liabilities of locomotor impairment, respiratory depression, acute tolerance development, and place conditioning were also assessed in vivo. All of the stereoisomers exhibited antinociception following either intracerebroventricular or oral administration differentially mediated by multiple opioid receptors, with kappa opioid receptor (KOR) activity contributing for all of the peptides. However, unlike the parent peptides, KOR antagonism was exhibited by only one stereoisomer, while another isomer produced DOR antagonism. The stereoisomers of CJ-15,208 lacked significant respiratory effects, while the [d-Trp]CJ-15,208 stereoisomers did not elicit antinociceptive tolerance. Two isomers, cyclo[d-Phe-d-Pro-d-Phe-Trp] (3) and cyclo[Phe-d-Pro-d-Phe-d-Trp] (5), did not elicit either preference or aversion in a conditioned place preference assay. Collectively, these stereoisomers represent new lead compounds for further investigation in the development of safer opioid analgesics.
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Affiliation(s)
- Ariana C. Brice-Tutt
- Department of Pharmacodynamics, The University of Florida, Gainesville, FL 32610, USA; (A.C.B.-T.); (S.O.E.)
| | | | - Michelle L. Ganno
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, FL 34987, USA;
| | - Shainnel O. Eans
- Department of Pharmacodynamics, The University of Florida, Gainesville, FL 32610, USA; (A.C.B.-T.); (S.O.E.)
| | - Tanvir Khaliq
- Department of Medicinal Chemistry, The University of Florida, Gainesville, FL 32610, USA;
| | - Thomas F. Murray
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA;
| | - Jay P. McLaughlin
- Department of Pharmacodynamics, The University of Florida, Gainesville, FL 32610, USA; (A.C.B.-T.); (S.O.E.)
- Correspondence: (J.P.M.); (J.V.A.); Tel.: +1-352-273-7207 (J.P.M.); +1-352-273-8708 (J.V.A.)
| | - Jane V. Aldrich
- Department of Medicinal Chemistry, The University of Florida, Gainesville, FL 32610, USA;
- Correspondence: (J.P.M.); (J.V.A.); Tel.: +1-352-273-7207 (J.P.M.); +1-352-273-8708 (J.V.A.)
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Sequeira E, Pierce ML, Akasheh D, Sellers S, Gerwick WH, Baden DG, Murray TF. Epicortical Brevetoxin Treatment Promotes Neural Repair and Functional Recovery after Ischemic Stroke. Mar Drugs 2020; 18:md18070374. [PMID: 32708077 PMCID: PMC7404386 DOI: 10.3390/md18070374] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [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: 06/25/2020] [Revised: 07/17/2020] [Accepted: 07/17/2020] [Indexed: 02/01/2023] Open
Abstract
Emerging literature suggests that after a stroke, the peri-infarct region exhibits dynamic changes in excitability. In rodent stroke models, treatments that enhance excitability in the peri-infarct cerebral cortex promote motor recovery. This increase in cortical excitability and plasticity is opposed by increases in tonic GABAergic inhibition in the peri-infarct zone beginning three days after a stroke in a mouse model. Maintenance of a favorable excitatory-inhibitory balance promoting cerebrocortical excitability could potentially improve recovery. Brevetoxin-2 (PbTx-2) is a voltage-gated sodium channel (VGSC) gating modifier that increases intracellular sodium ([Na+]i), upregulates N-methyl-D-aspartate receptor (NMDAR) channel activity and engages downstream calcium (Ca2+) signaling pathways. In immature cerebrocortical neurons, PbTx-2 promoted neuronal structural plasticity by increasing neurite outgrowth, dendritogenesis and synaptogenesis. We hypothesized that PbTx-2 may promote excitability and structural remodeling in the peri-infarct region, leading to improved functional outcomes following a stroke. We tested this hypothesis using epicortical application of PbTx-2 after a photothrombotic stroke in mice. We show that PbTx-2 enhanced the dendritic arborization and synapse density of cortical layer V pyramidal neurons in the peri-infarct cortex. PbTx-2 also produced a robust improvement of motor recovery. These results suggest a novel pharmacologic approach to mimic activity-dependent recovery from stroke.
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Affiliation(s)
- Erica Sequeira
- Department of Pharmacology and Neuroscience, Creighton University, Omaha, NE 68123, USA; (E.S.); (M.L.P.); (D.A.); (S.S.)
| | - Marsha L. Pierce
- Department of Pharmacology and Neuroscience, Creighton University, Omaha, NE 68123, USA; (E.S.); (M.L.P.); (D.A.); (S.S.)
| | - Dina Akasheh
- Department of Pharmacology and Neuroscience, Creighton University, Omaha, NE 68123, USA; (E.S.); (M.L.P.); (D.A.); (S.S.)
| | - Stacey Sellers
- Department of Pharmacology and Neuroscience, Creighton University, Omaha, NE 68123, USA; (E.S.); (M.L.P.); (D.A.); (S.S.)
| | - William H. Gerwick
- Center for Marine Biotechnology & Biomedicine, Scripps Institution of Oceanography, San Diego, La Jolla, CA 92093, USA;
| | - Daniel G. Baden
- Center for Marine Science University of North Carolina Wilmington, Wilmington, NC 28409, USA;
| | - Thomas F. Murray
- Department of Pharmacology and Neuroscience, Creighton University, Omaha, NE 68123, USA; (E.S.); (M.L.P.); (D.A.); (S.S.)
- Correspondence:
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Ferracane MJ, Brice-Tutt AC, Coleman JS, Simpson GG, Wilson LL, Eans SO, Stacy HM, Murray TF, McLaughlin JP, Aldrich JV. Design, Synthesis, and Characterization of the Macrocyclic Tetrapeptide cyclo[Pro-Sar-Phe-d-Phe]: A Mixed Opioid Receptor Agonist-Antagonist Following Oral Administration. ACS Chem Neurosci 2020; 11:1324-1336. [PMID: 32251585 DOI: 10.1021/acschemneuro.0c00086] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Substance abuse remains a serious public health crisis, affecting millions of people worldwide. Macrocyclic tetrapeptides like CJ-15,208 and [d-Trp]CJ-15,208 demonstrate opioid activity shown to attenuate the rewarding effects of cocaine in conditioned place preference assays in mice, making them promising lead compounds for treating substance abuse. In the present study, we report the rational design, synthesis, conformational analysis, and continued pharmacological evaluation of the novel macrocyclic tetrapeptide cyclo[Pro-Sar-Phe-d-Phe] to further explore this unique molecular scaffold. This peptide was rationally designed based on X-ray and NMR structures of related macrocyclic tetrapeptides. Following synthesis, its solution-phase conformations were determined by NMR and molecular modeling. The peptide adopted multiple conformations in polar solvents, but a single conformation in chloroform that is stabilized by intramolecular hydrogen bonding. The peptide is orally bioavailable, producing antinociception and antagonism of kappa opioid receptor (KOR) stimulation following oral administration in a mouse 55 °C warm-water tail-withdrawal assay. Notably, cyclo[Pro-Sar-Phe-d-Phe] blocked both stress- and drug-induced reinstatement of cocaine and morphine conditioned place preference in mice following oral administration, and displayed a decreased side-effect profile compared to morphine. Thus, cyclo[Pro-Sar-Phe-d-Phe] is a promising lead compound for the treatment of substance abuse.
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Affiliation(s)
- Michael J. Ferracane
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
- Department of Chemistry, University of Redlands, Redlands, California 92373, United States
| | - Ariana C. Brice-Tutt
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Jeremy S. Coleman
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Grant G. Simpson
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Lisa L. Wilson
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Shainnel O. Eans
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Heather M. Stacy
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Thomas F. Murray
- Department of Pharmacology, School of Medicine, Creighton University, Omaha, Nebraska 68178, United States
| | - Jay P. McLaughlin
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Jane V. Aldrich
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
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9
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Li Y, Yu HB, Zhang Y, Leao T, Glukhov E, Pierce ML, Zhang C, Kim H, Mao HH, Fang F, Cottrell GW, Murray TF, Gerwick L, Guan H, Gerwick WH. Pagoamide A, a Cyclic Depsipeptide Isolated from a Cultured Marine Chlorophyte, Derbesia sp., Using MS/MS-Based Molecular Networking. J Nat Prod 2020; 83:617-625. [PMID: 31916778 PMCID: PMC7210564 DOI: 10.1021/acs.jnatprod.9b01019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A thiazole-containing cyclic depsipeptide with 11 amino acid residues, named pagoamide A (1), was isolated from laboratory cultures of a marine Chlorophyte, Derbesia sp. This green algal sample was collected from America Samoa, and pagoamide A was isolated using guidance by MS/MS-based molecular networking. Cultures were grown in a light- and temperature-controlled environment and harvested after several months of growth. The planar structure of pagoamide A (1) was characterized by detailed 1D and 2D NMR experiments along with MS and UV analysis. The absolute configurations of its amino acid residues were determined by advanced Marfey's analysis following chemical hydrolysis and hydrazinolysis reactions. Two of the residues in pagoamide A (1), phenylalanine and serine, each occurred twice in the molecule, once in the d- and once in the l-configuration. The biosynthetic origin of pagoamide A (1) was considered in light of other natural products investigations with coenocytic green algae.
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Affiliation(s)
- Yueying Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, People’s Republic of China
- University of California, San Diego, La Jolla, California 92093, United States
| | - Hao-Bing Yu
- University of California, San Diego, La Jolla, California 92093, United States
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Second Military Medical University, Shanghai 200433, People’s Republic of China
| | - Yi Zhang
- University of California, San Diego, La Jolla, California 92093, United States
- College of Food Science and Technology, Guangdong Ocean University, Zhanjiang 524088, People’s Republic of China
| | - Tiago Leao
- University of California, San Diego, La Jolla, California 92093, United States
| | - Evgenia Glukhov
- University of California, San Diego, La Jolla, California 92093, United States
| | - Marsha L. Pierce
- Department of Pharmacology, School of Medicine, Creighton University, Omaha, Nebraska 68178, United States
| | - Chen Zhang
- University of California, San Diego, La Jolla, California 92093, United States
- Department of Computer Sciences and Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Hyunwoo Kim
- University of California, San Diego, La Jolla, California 92093, United States
| | - Huanru Henry Mao
- Department of Computer Sciences and Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Fang Fang
- University of California, San Diego, La Jolla, California 92093, United States
| | - Garrison W. Cottrell
- Department of Computer Sciences and Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Thomas F. Murray
- Department of Pharmacology, School of Medicine, Creighton University, Omaha, Nebraska 68178, United States
| | - Lena Gerwick
- University of California, San Diego, La Jolla, California 92093, United States
| | - Huashi Guan
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, People’s Republic of China
| | - William H. Gerwick
- University of California, San Diego, La Jolla, California 92093, United States
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
- To whom correspondence should be addressed. Tel: (858)-534-0578.
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10
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Pierce ML, French JA, Murray TF. Comparison of the pharmacological profiles of arginine vasopressin and oxytocin analogs at marmoset, macaque, and human vasopressin 1a receptor. Biomed Pharmacother 2020; 126:110060. [PMID: 32145592 DOI: 10.1016/j.biopha.2020.110060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 02/22/2020] [Accepted: 02/25/2020] [Indexed: 01/14/2023] Open
Abstract
Arginine vasopressin (AVP) and oxytocin (OT) are nonapeptides that bind to G-protein coupled receptors and influence social behaviors. Consensus mammalian AVP and OT (Leu8-OT) sequences are highly conserved. In marmosets, an amino acid change in the 8th position of the peptide (Pro8-OT) exhibits unique structural and functional properties. There is ∼85 % structural homology between the OT receptor (OTR) and vasopressin 1a receptor (V1aR) resulting in significant cross-reactivity between the ligands and receptors. Chinese hamster ovary (CHO) cells expressing marmoset (mV1aR), macaque (qV1aR), or human vasopressin receptor 1a (hV1aR) were used to assess AVP, Leu8-OT and Pro8-OT pharmacological profiles. To assess activation of Gq, functional assays were performed using Fluo-3 to measure ligand-induced Ca2+ mobilization. In all three V1aR-expressing cell lines, AVP was more potent than the OT ligands. To assess ligand-induced hyperpolarization, FLIPR Membrane Potential (FMP) assays were performed. In all three V1aR lines, AVP was more potent than the OT analogs. The distinctive U-shaped concentration-response curve displayed by AVP may reflect enhanced desensitization of the mV1aR and hV1aR, which is not observed with qV1aR. Evaluation of Ca2+-activated potassium (K+) channels using the inhibitors apamin, paxilline, and TRAM-34 demonstrated that both intermediate and large conductance Ca2+-activated K+ channels contributed to membrane hyperpolarization, with different pharmacological profiles identified for distinct ligand-receptor combinations. Taken together, these data suggest differences in ligand-receptor signaling that may underlie differences in social behavior. Integrative studies of behavior, genetics and ligand-receptor interaction will help elucidate the connection between receptor pharmacology and social behaviors.
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Affiliation(s)
- Marsha L Pierce
- Department of Pharmacology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE 68178, USA
| | - Jeffrey A French
- Department of Psychology, University of Nebraska Omaha, 6001 Dodge St., Omaha, NE 68182, USA
| | - Thomas F Murray
- Department of Pharmacology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE 68178, USA.
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11
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Pierce ML, French JA, Murray TF. Comparison of the pharmacologic profiles of arginine vasopressin and oxytocin analogs at marmoset, titi monkey, macaque, and human oxytocin receptors. Biomed Pharmacother 2020; 125:109832. [PMID: 32018219 PMCID: PMC7196279 DOI: 10.1016/j.biopha.2020.109832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 09/16/2019] [Revised: 12/05/2019] [Accepted: 12/13/2019] [Indexed: 11/27/2022] Open
Abstract
The oxytocin-arginine vasopressin (OT-AVP) ligand-receptor family influences a variety of physiological, behavioral, and social behavioral processes in the brain and periphery. The OT-AVP family is highly conserved in mammals, but recent discoveries have revealed remarkable diversity in OT ligands and receptors in New World Monkeys (NWMs) providing a unique opportunity to assess the effects of genetic variation on pharmacological signatures of peptide ligands. The consensus mammalian OT sequence has leucine in the 8th position (Leu8-OT), whereas a number of NWMs, including the marmoset, have proline in the 8th position (Pro8-OT) resulting in a more rigid tail structure. OT and AVP bind to OT’s cognate G-protein coupled receptor (OTR), which couples to various G-proteins (Gi/o, Gq, Gs) to stimulate diverse signaling pathways. CHO cells expressing marmoset (mOTR), titi monkey (tOTR), macaque (qOTR), or human (hOTR) OT receptors were used to compare AVP and OT analog-induced signaling. Assessment of Gq-mediated increase in intracellular calcium (Ca2+) demonstrated that AVP was less potent than OT analogs at OTRs from species whose endogenous ligand is Leu8-OT (tOTR, qOTR, hOTR), relative to Pro8-OT. Likewise, AVP-induced membrane hyperpolarization was less potent at these same OTRs. Evaluation of (Ca2+)-activated potassium (K+) channels using the inhibitors apamin, paxilline, and TRAM-34 demonstrated that both intermediate and large conductance Ca2+-activated K+ channels contributed to membrane hyperpolarization, with different pharmacological profiles identified for distinct ligand-receptor combinations. Understanding more fully the contributions of structure activity relationships for these peptide ligands at vasopressin and OT receptors will help guide the development of OT-mediated therapeutics.
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Affiliation(s)
- Marsha L Pierce
- Department of Pharmacology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA; Department of Pharmacology, Midwestern University, 555 31St., Downers Grove, IL, 60515, USA.
| | - Jeffrey A French
- Department of Psychology, University of Nebraska Omaha, 6001 Dodge St., Omaha, NE, 68182, USA.
| | - Thomas F Murray
- Department of Pharmacology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE, 68178, USA.
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12
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Arttamangkul S, Plazek A, Platt EJ, Jin H, Murray TF, Birdsong WT, Rice KC, Farrens DL, Williams JT. Visualizing endogenous opioid receptors in living neurons using ligand-directed chemistry. eLife 2019; 8:49319. [PMID: 31589142 PMCID: PMC6809603 DOI: 10.7554/elife.49319] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [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: 07/04/2019] [Accepted: 10/06/2019] [Indexed: 12/11/2022] Open
Abstract
Identifying neurons that have functional opioid receptors is fundamental for the understanding of the cellular, synaptic and systems actions of opioids. Current techniques are limited to post hoc analyses of fixed tissues. Here we developed a fluorescent probe, naltrexamine-acylimidazole (NAI), to label opioid receptors based on a chemical approach termed ‘traceless affinity labeling’. In this approach, a high affinity antagonist naltrexamine is used as the guide molecule for a transferring reaction of acylimidazole at the receptor. This reaction generates a fluorescent dye covalently linked to the receptor while naltrexamine is liberated and leaves the binding site. The labeling induced by this reagent allowed visualization of opioid-sensitive neurons in rat and mouse brains without loss of function of the fluorescently labeled receptors. The ability to locate endogenous receptors in living tissues will aid considerably in establishing the distribution and physiological role of opioid receptors in the CNS of wild type animals.
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Affiliation(s)
- Seksiri Arttamangkul
- The Vollum Institute, Oregon Health & Science University, Portland, United States
| | - Andrew Plazek
- Medicinal Chemistry Core, Oregon Health & Science University, Portland, United States
| | - Emily J Platt
- Department of Biochemistry and Molecular Biology, School of Medicine, Oregon Health & Science University, Portland, United States
| | - Haihong Jin
- Medicinal Chemistry Core, Oregon Health & Science University, Portland, United States
| | - Thomas F Murray
- Department of Pharmacology, School of Medicine, Creighton University, Omaha, United States
| | - William T Birdsong
- The Vollum Institute, Oregon Health & Science University, Portland, United States
| | - Kenner C Rice
- Drug Design and Synthesis Section, Intramural Research Program, NIDA and NIAAA, Bethesda, United States
| | - David L Farrens
- Department of Biochemistry and Molecular Biology, School of Medicine, Oregon Health & Science University, Portland, United States
| | - John T Williams
- The Vollum Institute, Oregon Health & Science University, Portland, United States
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13
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Pierce ML, Mehrotra S, Mustoe AC, French JA, Murray TF. A Comparison of the Ability of Leu 8- and Pro 8-Oxytocin to Regulate Intracellular Ca 2+ and Ca 2+-Activated K + Channels at Human and Marmoset Oxytocin Receptors. Mol Pharmacol 2019; 95:376-385. [PMID: 30739093 DOI: 10.1124/mol.118.114744] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/30/2019] [Indexed: 02/02/2023] Open
Abstract
The neurohypophyseal hormone oxytocin (OT) regulates biologic functions in both peripheral tissues and the central nervous system. In the central nervous system, OT influences social processes, including peer relationships, maternal-infant bonding, and affiliative social relationships. In mammals, the nonapeptide OT structure is highly conserved with leucine in the eighth position (Leu8-OT). In marmosets (Callithrix), a nonsynonymous nucleotide substitution in the OXT gene codes for proline in the eighth residue position (Pro8-OT). OT binds to its cognate G protein-coupled receptor (OTR) and exerts diverse effects, including stimulation (Gs) or inhibition (Gi/o) of adenylyl cyclase, stimulation of potassium channel currents (Gi), and activation of phospholipase C (Gq). Chinese hamster ovary cells expressing marmoset or human oxytocin receptors (mOTRs or hOTRs, respectively) were used to characterize OT signaling. At the mOTR, Pro8-OT was more efficacious than Leu8-OT in measures of Gq activation, with both peptides displaying subnanomolar potencies. At the hOTR, neither the potency nor efficacy of Pro8-OT and Leu8-OT differed with respect to Gq signaling. In both mOTR- and hOTR-expressing cells, Leu8-OT was more potent and modestly more efficacious than Pro8-OT in inducing hyperpolarization. In mOTR cells, Leu8-OT-induced hyperpolarization was modestly inhibited by pretreatment with pertussis toxin (PTX), consistent with a minor role for Gi/o activation; however, the Pro8-OT response in mOTR and hOTR cells was PTX insensitive. These findings are consistent with membrane hyperpolarization being largely mediated by a Gq signaling mechanism leading to Ca2+-dependent activation of K+ channels. Evaluation of the influence of apamin, charybdotoxin, paxilline, and TRAM-34 demonstrated involvement of both intermediate and large conductance Ca2+-activated K+ channels.
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Affiliation(s)
- Marsha L Pierce
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska (M.L.P., S.M., T.F.M.); and Department of Psychology, University of Nebraska, Omaha, Nebraska (A.C.M., J.A.F.)
| | - Suneet Mehrotra
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska (M.L.P., S.M., T.F.M.); and Department of Psychology, University of Nebraska, Omaha, Nebraska (A.C.M., J.A.F.)
| | - Aaryn C Mustoe
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska (M.L.P., S.M., T.F.M.); and Department of Psychology, University of Nebraska, Omaha, Nebraska (A.C.M., J.A.F.)
| | - Jeffrey A French
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska (M.L.P., S.M., T.F.M.); and Department of Psychology, University of Nebraska, Omaha, Nebraska (A.C.M., J.A.F.)
| | - Thomas F Murray
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska (M.L.P., S.M., T.F.M.); and Department of Psychology, University of Nebraska, Omaha, Nebraska (A.C.M., J.A.F.)
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14
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Joshi AA, Murray TF, Aldrich JV. Alanine scan of the opioid peptide dynorphin B amide. Biopolymers 2018; 108. [PMID: 28464209 DOI: 10.1002/bip.23026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/24/2017] [Accepted: 04/24/2017] [Indexed: 11/06/2022]
Abstract
To date structure-activity relationship (SAR) studies of the dynorphins (Dyn), endogenous peptides for kappa opioid receptors (KOR), have focused almost exclusively on Dyn A with minimal studies on Dyn B. While both Dyn A and Dyn B have identical N-terminal sequences, their C-terminal sequences differ, which could result in differences in pharmacological activity. We performed an alanine scan of the non-glycine residues up through residue 11 of Dyn B amide to explore the roles of these side chains in the activity of Dyn B. The analogs were synthesized by fluorenylmethyloxycarbonyl (Fmoc)-based solid phase peptide synthesis and evaluated for their opioid receptor affinities and opioid potency and efficacy at KOR. Similar to Dyn A the N-terminal Tyr1 and Phe4 residues of Dyn B amide are critical for opioid receptor affinity and KOR agonist potency. The basic residues Arg6 and Arg7 contribute to the KOR affinity and agonist potency of Dyn B amide, while Lys10 contributes to the opioid receptor affinity, but not KOR agonist potency, of this peptide. Comparison to the Ala analogs of Dyn A (1-13) suggests that the basic residues in the C-terminus of both peptides contribute to KOR binding, but differences in their relative positions may contribute to the different pharmacological profiles of Dyn A and Dyn B. The other unique C-terminal residues in Dyn B amide also appear to influence the relative affinity of this peptide for KOR versus mu and delta opioid receptors. This SAR information may be applied in the design of new Dyn B analogs that could be useful pharmacological tools.
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Affiliation(s)
- Anand A Joshi
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas, 66045
| | - Thomas F Murray
- Department of Pharmacology, School of Medicine, Creighton University, Omaha, Nebraska, 68102
| | - Jane V Aldrich
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas, 66045.,Department of Medicinal Chemistry, University of Florida, Gainesville, Florida, 32610
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15
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Gomez DA, Murray TF. VOLTAGE‐GATED SODIUM CHANNEL ACTIVATION TRIGGERS CALCIUM INFLUX AND HIPPOCAMPAL NEURON COMPLEXITY. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.554.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Toews ML, Taylor JH, Schulte NA, Murray TF, French JA. Binding and Signaling Properties of the Leu
8
and Pro
8
Isoforms of Oxytocin for Oxytocin Receptors from Four Primate Species. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.555.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Myron L. Toews
- PharmacologyUniversity of Nebraska Medical CenterOmahaNE
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17
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Tao Y, Li P, Zhang D, Glukhov E, Gerwick L, Zhang C, Murray TF, Gerwick WH. Samholides, Swinholide-Related Metabolites from a Marine Cyanobacterium cf. Phormidium sp. J Org Chem 2018; 83:3034-3046. [PMID: 29457979 PMCID: PMC5859247 DOI: 10.1021/acs.joc.8b00028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
![]()
Cancer cell cytotoxicity was used
to guide the isolation of nine
new swinholide-related compounds, named samholides A–I (1–9), from an American Samoan marine cyanobacterium
cf. Phormidium sp. Their structures were determined
by extensive analysis of 1D and 2D NMR spectroscopic data. The new
compounds share an unusual 20-demethyl 44-membered lactone ring composed
of two monomers, and they demonstrate structural diversity arising
from geometric isomerization of double bonds, sugar units with unique
glyceryl moieties and varied methylation patterns. All of the new
samholides were potently active against the H-460 human lung cancer
cell line with IC50 values ranging from 170 to 910 nM.
The isolation of these new swinholide-related compounds from a marine
cyanobacterium reinvigorates questions concerning the evolution and
biosynthetic origin of these natural products.
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Affiliation(s)
- Yiwen Tao
- Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital , Guangzhou Medical University , Guangzhou 511436 , People's Republic of China.,Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography , University of California San Diego , La Jolla , California 92093 , United States
| | - Pinglin Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy , Ocean University of China , Qingdao 266003 , People's Republic of China.,Laboratory for Marine Drugs and Bioproducts , Qingdao National Laboratory for Marine Science and Technology , Qingdao 266235 , People's Republic of China.,Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography , University of California San Diego , La Jolla , California 92093 , United States
| | - Daojing Zhang
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography , University of California San Diego , La Jolla , California 92093 , United States.,State Key Laboratory of Bioreactor Engineering , East China University of Science & Technology , Shanghai 200237 , People's Republic of China
| | - Evgenia Glukhov
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography , University of California San Diego , La Jolla , California 92093 , United States
| | - Lena Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography , University of California San Diego , La Jolla , California 92093 , United States
| | - Chen Zhang
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography , University of California San Diego , La Jolla , California 92093 , United States
| | - Thomas F Murray
- Department of Pharmacology , Creighton University School of Medicine , Omaha , Nebraska 68178 , United States
| | - William H Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography , University of California San Diego , La Jolla , California 92093 , United States.,Skaggs School of Pharmacy and Pharmaceutical Sciences , University of California San Diego , La Jolla , California 92093 , United States
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18
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Fang WJ, Murray TF, Aldrich JV. Design, synthesis, and opioid activity of arodyn analogs cyclized by ring-closing metathesis involving Tyr(allyl). Bioorg Med Chem 2017; 26:1157-1161. [PMID: 29273415 DOI: 10.1016/j.bmc.2017.11.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 11/14/2017] [Accepted: 11/17/2017] [Indexed: 01/31/2023]
Abstract
Kappa (κ) opioid receptor selective antagonists are useful pharmacological tools in studying κ opioid receptors and have potential to be used as therapeutic agents for the treatment of a variety of diseases including mood disorders and drug addiction. Arodyn (Ac[Phe1-3,Arg4,d-Ala8]Dyn A-(1-11)NH2) is a linear acetylated dynorphin A (Dyn A) analog that is a potent and selective κ opioid receptor antagonist (Bennett et al. J Med Chem 2002;45:5617-5619) and prevents stress-induced reinstatement of cocaine-seeking behavior following central administration (Carey et al. Eur J Pharmacol 2007;569:84-89). To restrict its conformational mobility, explore possible bioactive conformations and potentially increase its metabolic stability we synthesized cyclic arodyn analogs on solid phase utilizing a novel ring-closing metathesis (RCM) reaction involving allyl-protected Tyr (Tyr(All)) residues. This approach preserves the aromatic functionality and directly constrains the side chains of one or more of the Phe residues. The novel cyclic arodyn analog 4 cyclized between Tyr(All) residues incorporated in positions 2 and 3 exhibited potent κ opioid receptor antagonism in the [35S]GTPγS assay (KB = 3.2 nM) similar to arodyn. Analog 3 cyclized between Tyr(All) residues in positions 1 and 2 also exhibited nanomolar κ opioid receptor antagonist potency (KB = 27.5 nM) in this assay. These are the first opioid peptides cyclized via RCM involving aromatic residues, and given their promising pharmacological activity represent novel lead peptides for further exploration.
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Affiliation(s)
- Wei-Jie Fang
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66045, USA
| | - Thomas F Murray
- Department of Pharmacology, Creighton University, Omaha, NE 68178, USA
| | - Jane V Aldrich
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66045, USA; Department of Medicinal Chemistry, University of Florida, Gainesville, FL 32610, USA.
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19
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Naman CB, Almaliti J, Armstrong L, Caro-Díaz EJ, Pierce ML, Glukhov E, Fenner A, Spadafora C, Debonsi HM, Dorrestein PC, Murray TF, Gerwick WH. Discovery and Synthesis of Caracolamide A, an Ion Channel Modulating Dichlorovinylidene Containing Phenethylamide from a Panamanian Marine Cyanobacterium cf. Symploca Species. J Nat Prod 2017; 80:2328-2334. [PMID: 28783331 DOI: 10.1021/acs.jnatprod.7b00367] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A recent untargeted metabolomics investigation into the chemical profile of 10 organic extracts from cf. Symploca spp. revealed several interesting chemical leads for further natural product drug discovery. Subsequent target-directed isolation efforts with one of these, a Panamanian marine cyanobacterium cf. Symploca sp., yielded a phenethylamide metabolite that terminates in a relatively rare gem-dichlorovinylidene moiety, caracolamide A (1), along with a known isotactic polymethoxy-1-alkene (2). Detailed NMR and HRESIMS analyses were used to determine the structures of these molecules, and compound 1 was confirmed by a three-step synthesis. Pure compound 1 was shown to have in vitro calcium influx and calcium channel oscillation modulatory activity when tested as low as 10 pM using cultured murine cortical neurons, but was not cytotoxic to NCI-H460 human non-small-cell lung cancer cells in vitro (IC50 > 10 μM).
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Affiliation(s)
- C Benjamin Naman
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego , La Jolla, California 92093, United States
| | - Jehad Almaliti
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego , La Jolla, California 92093, United States
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, The University of Jordan , Amman, 11942, Jordan
| | - Lorene Armstrong
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego , La Jolla, California 92093, United States
- Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo , Avenida Do Café, s/n, Campus Universitário, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
| | - Eduardo J Caro-Díaz
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego , La Jolla, California 92093, United States
| | - Marsha L Pierce
- Department of Pharmacology, Creighton University School of Medicine , 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - Evgenia Glukhov
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego , La Jolla, California 92093, United States
| | - Amanda Fenner
- Center of Cellular and Molecular Biology of Diseases, City of Knowledge, Instituto de Investigaciones Científicas y Sevicios de Alta Tecnología , Bldg. 219, P.O. Box 7250, Panama 5, Republic of Panama
| | - Carmenza Spadafora
- Center of Cellular and Molecular Biology of Diseases, City of Knowledge, Instituto de Investigaciones Científicas y Sevicios de Alta Tecnología , Bldg. 219, P.O. Box 7250, Panama 5, Republic of Panama
| | - Hosana M Debonsi
- Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo , Avenida Do Café, s/n, Campus Universitário, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil
| | - Pieter C Dorrestein
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego , La Jolla, California 92093, United States
| | - Thomas F Murray
- Department of Pharmacology, Creighton University School of Medicine , 2500 California Plaza, Omaha, Nebraska 68178, United States
| | - William H Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego , La Jolla, California 92093, United States
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego , La Jolla, California 92093, United States
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20
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Kinnel RB, Esquenazi E, Leao T, Moss N, Mevers E, Pereira AR, Monroe EA, Korobeynikov A, Murray TF, Sherman D, Gerwick L, Dorrestein PC, Gerwick WH. A Maldiisotopic Approach to Discover Natural Products: Cryptomaldamide, a Hybrid Tripeptide from the Marine Cyanobacterium Moorea producens. J Nat Prod 2017; 80:1514-1521. [PMID: 28448144 PMCID: PMC5748289 DOI: 10.1021/acs.jnatprod.7b00019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Genome sequencing of microorganisms has revealed a greatly increased capacity for natural products biosynthesis than was previously recognized from compound isolation efforts alone. Hence, new methods are needed for the discovery and description of this hidden secondary metabolite potential. Here we show that provision of heavy nitrogen 15N-nitrate to marine cyanobacterial cultures followed by single-filament MALDI analysis over a period of days was highly effective in identifying a new natural product with an exceptionally high nitrogen content. The compound, named cryptomaldamide, was subsequently isolated using MS to guide the purification process, and its structure determined by 2D NMR and other spectroscopic and chromatographic methods. Bioinformatic analysis of the draft genome sequence identified a 28.7 kB gene cluster that putatively encodes for cryptomaldamide biosynthesis. Notably, an amidinotransferase is proposed to initiate the biosynthetic process by transferring an amidino group from arginine to serine to produce the first residue to be incorporated by the hybrid NRPS-PKS pathway. The maldiisotopic approach presented here is thus demonstrated to provide an orthogonal method by which to discover novel chemical diversity from Nature.
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Affiliation(s)
- Robin B. Kinnel
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, USA
- Department of Chemistry, Hamilton College, Clinton, NY, USA
| | | | - Tiago Leao
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, USA
| | - Nathan Moss
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, USA
| | - Emily Mevers
- Department of Chemistry and Biochemistry, University of California San Diego, USA
| | - Alban R. Pereira
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, USA
| | - Emily A. Monroe
- Department of Biology, William Paterson University of New Jersey, USA
| | - Anton Korobeynikov
- Faculty of Mathematics and Mechanics and Center for Algorithmic Biotechnology, Saint Petersburg State University, Russia
| | - Thomas F. Murray
- Creighton University, School of Medicine, Department of Pharmacology, Omaha, NE, 68178, USA
| | - David Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan
| | - Lena Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, USA
| | - Pieter C. Dorrestein
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, USA
| | - William H. Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, USA
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21
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Philkhana SC, Mehrotra S, Murray TF, Reddy DS. Synthesis and biological evaluation of palmyrolide A macrocycles as sodium channel blockers towards neuroprotection. Org Biomol Chem 2016; 14:8457-73. [PMID: 27536802 DOI: 10.1039/c6ob01372d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Palmyrolide A is a neuroprotective macrolide isolated by Gerwick and coworkers in 2010. This natural product is known to suppress neuronal spontaneous calcium ion oscillations through its voltage-gated sodium channel blocking ability which is of significant interest in CNS drug discovery. Herein, we give a detailed account on total synthesis of (+)-palmyrolide A and synthesis of a focused library of macrocycles around the scaffold, followed by their biological evaluation. Use of the chiral pool approach, Zhu's oxidative homologation, access to unnatural cis-palmyrolide A, preparation of 18 new analogues and identification of macrolides with improved sodium channel blocking activity are the important features of the present paper. As a measure of potency as voltage-gated sodium channel blockers, all the synthesized analogues were profiled for their ability to inhibit the veratridine-stimulated Na(+) influx in murine primary neuronal cultures. Four macrocycles were found to be more potent or comparable to that of the natural product (-)-palmyrolide A. The most potent compound from this series 20 was structurally simplified and readily accessible in good quantities for further biological profiling.
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22
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Joshi AA, Murray TF, Aldrich JV. Structure-Activity Relationships of the Peptide Kappa Opioid Receptor Antagonist Zyklophin. J Med Chem 2015; 58:8783-95. [PMID: 26491810 DOI: 10.1021/jm501827k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The dynorphin (Dyn) A analogue zyklophin ([N-benzyl-Tyr(1)-cyclo(d-Asp(5),Dap(8))]dynorphin A(1-11)NH2) is a kappa opioid receptor (KOR)-selective antagonist in vitro, is active in vivo, and antagonizes KOR in the CNS after systemic administration. Hence, we synthesized zyklophin analogues to explore the structure-activity relationships of this peptide. The synthesis of selected analogues required modification to introduce the N-terminal amino acid due to poor solubility and/or to avoid epimerization of this residue. Among the N-terminal modifications, the N-phenethyl and N-cyclopropylmethyl substitutions resulted in analogues with the highest KOR affinities. Pharmacological results for the alanine-substituted analogues indicated that Phe(4) and Arg(6), but interestingly not the Tyr(1) phenol, are important for zyklophin's KOR affinity and that Arg(7) was important for KOR antagonist activity. In the GTPγS assay, while all of the cyclic analogues exhibited negligible KOR efficacy, the N-cyclopropylmethyl-Tyr(1) and N-benzyl-Phe(1) analogues were 28- and 11-fold more potent KOR antagonists, respectively, than zyklophin.
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Affiliation(s)
- Anand A Joshi
- Department of Medicinal Chemistry, The University of Kansas , Lawrence, Kansas 66045, United States
| | - Thomas F Murray
- Department of Pharmacology, School of Medicine, Creighton University , Omaha, Nebraska 68102, United States
| | - Jane V Aldrich
- Department of Medicinal Chemistry, The University of Kansas , Lawrence, Kansas 66045, United States
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23
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Boudreau PD, Monroe EA, Mehrotra S, Desfor S, Korobeynikov A, Sherman DH, Murray TF, Gerwick L, Dorrestein PC, Gerwick WH. Expanding the Described Metabolome of the Marine Cyanobacterium Moorea producens JHB through Orthogonal Natural Products Workflows. PLoS One 2015. [PMID: 26222584 PMCID: PMC4519256 DOI: 10.1371/journal.pone.0133297] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Moorea producens JHB, a Jamaican strain of tropical filamentous marine cyanobacteria, has been extensively studied by traditional natural products techniques. These previous bioassay and structure guided isolations led to the discovery of two exciting classes of natural products, hectochlorin (1) and jamaicamides A (2) and B (3). In the current study, mass spectrometry-based 'molecular networking' was used to visualize the metabolome of Moorea producens JHB, and both guided and enhanced the isolation workflow, revealing additional metabolites in these compound classes. Further, we developed additional insight into the metabolic capabilities of this strain by genome sequencing analysis, which subsequently led to the isolation of a compound unrelated to the jamaicamide and hectochlorin families. Another approach involved stimulation of the biosynthesis of a minor jamaicamide metabolite by cultivation in modified media, and provided insights about the underlying biosynthetic machinery as well as preliminary structure-activity information within this structure class. This study demonstrated that these orthogonal approaches are complementary and enrich secondary metabolomic coverage even in an extensively studied bacterial strain.
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Affiliation(s)
- Paul D. Boudreau
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, United States
| | - Emily A. Monroe
- Department of Biology, William Paterson University, Wayne, New Jersey, 07470, United States of America
| | - Suneet Mehrotra
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska, 68178, United States of America
| | - Shane Desfor
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, United States
- Department of Biology, California State University San Marcos, San Marcos, California, 92078, United States of America
| | - Anton Korobeynikov
- Algorithmic Biology Laboratory, St. Petersburg Academic University, Russian Academy of Sciences, St. Petersburg, 194021, Russia
- Department of Mathematics and Mechanics, St. Petersburg State University, St. Petersburg, 194021, Russia
- Center for Algorithmic Biotechnology, St. Petersburg State University, St. Petersburg, 194021, Russia
| | - David H. Sherman
- Life Sciences Institute and Department of Medical Chemistry, University of Michigan, Ann Arbor, Michigan, 48109, United States of America
| | - Thomas F. Murray
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska, 68178, United States of America
| | - Lena Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, United States
| | - Pieter C. Dorrestein
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, 92093, United States of America
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, 92093, United States of America
| | - William H. Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, United States
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, 92093, United States of America
- * E-mail:
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24
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Aldrich JV, Senadheera SN, Ross NC, Reilley KA, Ganno ML, Eans SE, Murray TF, McLaughlin JP. Alanine analogues of [D-Trp]CJ-15,208: novel opioid activity profiles and prevention of drug- and stress-induced reinstatement of cocaine-seeking behaviour. Br J Pharmacol 2015; 171:3212-22. [PMID: 24588614 DOI: 10.1111/bph.12664] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/30/2014] [Accepted: 02/24/2014] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE The novel macrocyclic peptide cyclo[Phe-D-Pro-Phe-D-Trp] ([D-Trp]CJ-15,208) exhibits κ opioid (KOP) receptor antagonist activity in both in vitro and in vivo assays. The four alanine analogues of this peptide were synthesized and characterized both in vitro and in vivo to assess the contribution of different amino acid residues to the activity of [D-Trp]CJ-15,208. EXPERIMENTAL APPROACH The peptides were synthesized by a combination of solid phase peptide synthesis and cyclization in solution. The analogues were evaluated in vitro in receptor binding and functional assays, and in vivo with mice using a tail-withdrawal assay for antinociceptive and opioid antagonist activity. Mice demonstrating extinction of cocaine conditioned-place preference (CPP) were pretreated with selected analogues to evaluate prevention of stress or cocaine-induced reinstatement of CPP. KEY RESULTS The alanine analogues displayed pharmacological profiles in vivo distinctly different from [D-Trp]CJ-15,208. While the analogues exhibited varying opioid receptor affinities and κ and μ opioid receptor antagonist activity in vitro, they produced potent opioid receptor-mediated antinociception (ED50 = 0.28-4.19 nmol, i.c.v.) in vivo. Three of the analogues also displayed KOP receptor antagonist activity in vivo. Pretreatment with an analogue exhibiting both KOP receptor agonist and antagonist activity in vivo prevented both cocaine- and stress-induced reinstatement of cocaine-seeking behaviour in the CPP assay in a time-dependent manner. CONCLUSIONS AND IMPLICATIONS These unusual macrocyclic peptides exhibit in vivo opioid activity profiles different from the parent compound and represent novel compounds for potential development as therapeutics for drug abuse and possibly as analgesics.
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Affiliation(s)
- J V Aldrich
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, KS, USA
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25
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Mehrotra S, Duggan BM, Tello-Aburto R, Newar TD, Gerwick W, Murray TF, Maio WA. Detailed analysis of (-)-palmyrolide a and some synthetic derivatives as voltage-gated sodium channel antagonists. J Nat Prod 2014; 77:2553-2560. [PMID: 25343669 PMCID: PMC4251536 DOI: 10.1021/np500644k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Indexed: 06/04/2023]
Abstract
A small library of synthetic (-)-palmyrolide A diastereomers, analogues, and acyclic precursors have been examined with respect to their interaction with voltage-gated sodium channels (VGSCs). Toward this goal, the ability of (-)-palmyrolide A and analogues to antagonize veratridine-stimulated Na(+) influx in primary cultures of mouse cerebrocortical neurons was assessed. We found that synthetic (-)-palmyrolide A and its enantiomer functioned as VGSC antagonists to block veratridine-induced sodium influx. A detailed NMR and computational analysis of four diastereomers revealed that none had the same combination of shape and electrostatic potential as exhibited by natural (-)-palmyrolide A. These data indicate that the relative configuration about the tert-butyl and methyl substituents appears to be a prerequisite for biological function. Additional testing revealed that the enamide double bond was not necessary for blocking veratridine-induced sodium influx, whereas the acyclic analogues and other macrolide diastereomers tested were inactive as inhibitors of VGSCs, suggesting that the intact macrolide was required.
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Affiliation(s)
- Suneet Mehrotra
- Department
of Pharmacology, Creighton University School
of Medicine, Omaha, Nebraska 68178, United
States
| | - Brendan M. Duggan
- Center
for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography
and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92037, United States
| | - Rodolfo Tello-Aburto
- Department
of Chemistry and Biochemistry, New Mexico
State University, Las Cruces, New Mexico 88003, United States
| | - Tara D. Newar
- Department
of Chemistry and Biochemistry, New Mexico
State University, Las Cruces, New Mexico 88003, United States
| | - William
H. Gerwick
- Center
for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography
and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92037, United States
| | - Thomas F. Murray
- Department
of Pharmacology, Creighton University School
of Medicine, Omaha, Nebraska 68178, United
States
| | - William A. Maio
- Department
of Chemistry and Biochemistry, New Mexico
State University, Las Cruces, New Mexico 88003, United States
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26
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Cao Z, Cui Y, Busse E, Mehrotra S, Rainier JD, Murray TF. Gambierol inhibition of voltage-gated potassium channels augments spontaneous Ca2+ oscillations in cerebrocortical neurons. J Pharmacol Exp Ther 2014; 350:615-23. [PMID: 24957609 DOI: 10.1124/jpet.114.215319] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Gambierol is a marine polycyclic ether toxin produced by the marine dinoflagellate Gambierdiscus toxicus and is a member of the ciguatoxin toxin family. Gambierol has been demonstrated to be either a low-efficacy partial agonist/antagonist of voltage-gated sodium channels or a potent blocker of voltage-gated potassium channels (Kvs). Here we examined the influence of gambierol on intact cerebrocortical neurons. We found that gambierol produced both a concentration-dependent augmentation of spontaneous Ca(2+) oscillations, and an inhibition of Kv channel function with similar potencies. In addition, an array of selective as well as universal Kv channel inhibitors mimicked gambierol in augmenting spontaneous Ca(2+) oscillations in cerebrocortical neurons. These data are consistent with a gambierol blockade of Kv channels underlying the observed increase in spontaneous Ca(2+) oscillation frequency. We also found that gambierol produced a robust stimulation of phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2). Gambierol-stimulated ERK1/2 activation was dependent on both inotropic [N-methyl-d-aspartate (NMDA)] and type I metabotropic glutamate receptors (mGluRs) inasmuch as MK-801 [NMDA receptor inhibitor; (5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate], S-(4)-CGP [S-(4)-carboxyphenylglycine], and MTEP [type I mGluR inhibitors; 3-((2-methyl-4-thiazolyl)ethynyl) pyridine] attenuated the response. In addition, 2-aminoethoxydiphenylborane, an inositol 1,4,5-trisphosphate receptor inhibitor, and U73122 (1-[6-[[(17b)-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione), a phospholipase C inhibitor, both suppressed gambierol-induced ERK1/2 activation, further confirming the role of type I mGluR-mediated signaling in the observed ERK1/2 activation. Finally, we found that gambierol produced a concentration-dependent stimulation of neurite outgrowth that was mimicked by 4-aminopyridine, a universal potassium channel inhibitor. Considered together, these data demonstrate that gambierol alters both Ca(2+) signaling and neurite outgrowth in cerebrocortical neurons as a consequence of blockade of Kv channels.
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Affiliation(s)
- Zhengyu Cao
- State Key Laboratory of Natural Medicines, Department of Complex Prescription of Traditional Chinese Medicine, China Pharmaceutical University, Nanjing, People's Republic of China (Z.C.); Department of Pharmacology, School of Medicine, Creighton University, Omaha, Nebraska (Z.C., Y.C., E.B., S.M., T.F.M.); and Department of Chemistry, University of Utah, Salt Lake City, Utah (J.D.R.)
| | - Yanjun Cui
- State Key Laboratory of Natural Medicines, Department of Complex Prescription of Traditional Chinese Medicine, China Pharmaceutical University, Nanjing, People's Republic of China (Z.C.); Department of Pharmacology, School of Medicine, Creighton University, Omaha, Nebraska (Z.C., Y.C., E.B., S.M., T.F.M.); and Department of Chemistry, University of Utah, Salt Lake City, Utah (J.D.R.)
| | - Eric Busse
- State Key Laboratory of Natural Medicines, Department of Complex Prescription of Traditional Chinese Medicine, China Pharmaceutical University, Nanjing, People's Republic of China (Z.C.); Department of Pharmacology, School of Medicine, Creighton University, Omaha, Nebraska (Z.C., Y.C., E.B., S.M., T.F.M.); and Department of Chemistry, University of Utah, Salt Lake City, Utah (J.D.R.)
| | - Suneet Mehrotra
- State Key Laboratory of Natural Medicines, Department of Complex Prescription of Traditional Chinese Medicine, China Pharmaceutical University, Nanjing, People's Republic of China (Z.C.); Department of Pharmacology, School of Medicine, Creighton University, Omaha, Nebraska (Z.C., Y.C., E.B., S.M., T.F.M.); and Department of Chemistry, University of Utah, Salt Lake City, Utah (J.D.R.)
| | - Jon D Rainier
- State Key Laboratory of Natural Medicines, Department of Complex Prescription of Traditional Chinese Medicine, China Pharmaceutical University, Nanjing, People's Republic of China (Z.C.); Department of Pharmacology, School of Medicine, Creighton University, Omaha, Nebraska (Z.C., Y.C., E.B., S.M., T.F.M.); and Department of Chemistry, University of Utah, Salt Lake City, Utah (J.D.R.)
| | - Thomas F Murray
- State Key Laboratory of Natural Medicines, Department of Complex Prescription of Traditional Chinese Medicine, China Pharmaceutical University, Nanjing, People's Republic of China (Z.C.); Department of Pharmacology, School of Medicine, Creighton University, Omaha, Nebraska (Z.C., Y.C., E.B., S.M., T.F.M.); and Department of Chemistry, University of Utah, Salt Lake City, Utah (J.D.R.)
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27
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Lesma G, Salvadori S, Airaghi F, Murray TF, Recca T, Sacchetti A, Balboni G, Silvani A. Structural and biological exploration of phe(3)-phe(4)-modified endomorphin-2 peptidomimetics. ACS Med Chem Lett 2013; 4:795-9. [PMID: 24900748 DOI: 10.1021/ml400189r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 07/11/2013] [Indexed: 12/24/2022] Open
Abstract
This study reports on our ongoing investigation on hybrid EM-2 analogues, in which the great potential of β-amino acids was exploited to generate multiple conformational modifications at the key positions 3 and 4 of the parent peptide. The effect on the opioid binding affinity was evaluated, by means of ligand stimulated binding assays, which indicated a high nanomolar affinity toward the μ-receptor, with appreciable μ/δ selectivity, for some of the new compounds. The three-dimensional properties of the high affinity μ opioid receptor (MOR) ligands were investigated by proton nuclear magnetic resonance, molecular dynamics, and docking studies. In solution, the structures showed extended conformations, which are in agreement with the commonly accepted pharmacophore model for EM-2. From docking studies on an active form of the MOR model, different ligand-receptor interactions have been identified, thus confirming the ability of active compounds to assume a biologically active conformation.
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Affiliation(s)
- Giordano Lesma
- Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi, 19, 20133 Milano, Italy
| | - Severo Salvadori
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Ferrara, via Fossato
di Mortara 17-19, 44100 Ferrara, Italy
| | - Francesco Airaghi
- Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi, 19, 20133 Milano, Italy
| | - Thomas F. Murray
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska 68102,
United States
| | - Teresa Recca
- Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi, 19, 20133 Milano, Italy
| | - Alessandro Sacchetti
- Dipartimento
di Chimica, Materiali ed Ingegneria Chimica ‘Giulio Natta’, Politecnico di Milano, p.zza Leonardo
da Vinci 32, 20133 Milano, Italy
| | - Gianfranco Balboni
- Dipartimento di Scienze della Vita e dell’Ambiente, Università degli Studi di Cagliari, Via Ospedale
72, 09124 Cagliari, Italy
| | - Alessandra Silvani
- Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi, 19, 20133 Milano, Italy
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Li H, Bowling JJ, Fronczek FR, Hong J, Jabba SV, Murray TF, Ha NC, Hamann MT, Jung JH. Asteropsin A: an unusual cystine-crosslinked peptide from porifera enhances neuronal Ca2+ influx. Biochim Biophys Acta Gen Subj 2013. [PMID: 23201194 DOI: 10.1016/j.bbagen.2012.11.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Herein we report the discovery of a cystine-crosslinked peptide from Porifera along with high-quality spatial details accompanied by the description of its unique effect on neuronal calcium influx. METHODS Asteropsin A (ASPA) was isolated from the marine sponge Asteropus sp., and its structure was independently determined using X-ray crystallography (0.87 angstroms) and solution NMR spectroscopy. RESULTS An N-terminal pyroglutamate modification, uncommon cis proline conformations, and absence of basic residues helped distinguish ASPA from other cystine-crosslinked knot peptides. ASPA enhanced Ca2+ influx in murine cerebrocortical neuron cells following the addition of the Na+ channel activator veratridine but did not modify the oscillation frequency or amplitude of neuronal Ca2+ currents alone. Allosterism at neurotoxin site 2 was not observed, suggesting an alternative to the known Na+ channel interaction. CONCLUSIONS Together with a distinct biological activity, the origin of ASPA suggests a new subclass of cystine-rich knot peptides associated with Porifera. GENERAL SIGNIFICANCE The discovery of ASPA represents a distinctive addition to an emerging subclass of cystine-crosslinked knot peptides from Porifera.
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Affiliation(s)
- Huayue Li
- College of Pharmacy, Pusan National University, Busan 609-735, Korea.
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29
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Reith MEA, Ali S, Hashim A, Sheikh IS, Theddu N, Gaddiraju NV, Mehrotra S, Schmitt KC, Murray TF, Sershen H, Unterwald EM, Davis FA. Novel C-1 substituted cocaine analogs unlike cocaine or benztropine. J Pharmacol Exp Ther 2012; 343:413-25. [PMID: 22895898 DOI: 10.1124/jpet.112.193771] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Despite a wealth of information on cocaine-like compounds, there is no information on cocaine analogs with substitutions at C-1. Here, we report on (R)-(-)-cocaine analogs with various C-1 substituents: methyl (2), ethyl (3), n-propyl (4), n-pentyl (5), and phenyl (6). Analog 2 was equipotent to cocaine as an inhibitor of the dopamine transporter (DAT), whereas 3 and 6 were 3- and 10-fold more potent, respectively. None of the analogs, however, stimulated mouse locomotor activity, in contrast to cocaine. Pharmacokinetic assays showed compound 2 occupied mouse brain rapidly, as cocaine itself; moreover, 2 and 6 were behaviorally active in mice in the forced-swim test model of depression and the conditioned place preference test. Analog 2 was a weaker inhibitor of voltage-dependent Na+ channels than cocaine, although 6 was more potent than cocaine, highlighting the need to assay future C-1 analogs for this activity. Receptorome screening indicated few significant binding targets other than the monoamine transporters. Benztropine-like "atypical" DAT inhibitors are known to display reduced cocaine-like locomotor stimulation, presumably by their propensity to interact with an inward-facing transporter conformation. However, 2 and 6, like cocaine, but unlike benztropine, exhibited preferential interaction with an outward-facing conformation upon docking in our DAT homology model. In summary, C-1 cocaine analogs are not cocaine-like in that they are not stimulatory in vivo. However, they are not benztropine-like in binding mechanism and seem to interact with the DAT similarly to cocaine. The present data warrant further consideration of these novel cocaine analogs for antidepressant or cocaine substitution potential.
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Affiliation(s)
- Maarten E A Reith
- Department of Psychiatry, New York University School of Medicine, 450 E 29th Street, Alexandria Building Room 803, New York, NY 10016, USA.
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30
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Ross NC, Reilley KJ, Murray TF, Aldrich JV, McLaughlin JP. Novel opioid cyclic tetrapeptides: Trp isomers of CJ-15,208 exhibit distinct opioid receptor agonism and short-acting κ opioid receptor antagonism. Br J Pharmacol 2012; 165:1097-108. [PMID: 21671905 DOI: 10.1111/j.1476-5381.2011.01544.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The κ opioid receptor antagonists demonstrate potential for maintaining abstinence from psychostimulant abuse, but existing non-peptide κ-receptor selective antagonists show exceptionally long activity. We hypothesized that the L- and D-Trp isomers of CJ-15,208, a natural cyclic tetrapeptide reported to be a κ-receptor antagonist in vitro, would demonstrate short-acting, dose-dependent antagonism in vivo, preventing reinstatement of cocaine-seeking behaviour. EXPERIMENTAL APPROACH Affinity, selectivity and efficacy of the L-Trp and D-Trp isomers for opioid receptors were assessed in vitro in radioligand and GTPγS binding assays. Opioid receptor agonist and antagonist activities were characterized in vivo following i.c.v. administration with the 55°C warm water tail-withdrawal assay. The D-Trp isomer, which demonstrated primarily κ-receptor selective antagonist activity, was further evaluated for its prevention of stress- and drug-induced reinstatement of extinguished cocaine conditioned place preference (CPP). KEY RESULTS The two isomers showed similar affinity and selectivity for κ receptors (K(i) 30-35 nM) as well as κ receptor antagonism in vitro. As expected, the D-Trp cyclic tetrapeptide exhibited minimal agonist activity and induced dose-dependent κ-receptor selective antagonism lasting less than 18 h in vivo. Pretreatment with this peptide prevented stress-, but not cocaine-induced, reinstatement of extinguished cocaine CPP. In contrast, the L-Trp cyclic tetrapeptide unexpectedly demonstrated mixed opioid agonist/antagonist activity. CONCLUSIONS AND IMPLICATIONS The L-Trp and the D-Trp isomers of CJ-15,208 demonstrate stereospecific opioid activity in vivo. The relatively brief κ opioid receptor antagonism, coupled with the prevention of stress-induced reinstatement of extinguished cocaine-seeking behaviour, suggests the D-Trp isomer could be used therapeutically to maintain abstinence from psychostimulant abuse.
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Affiliation(s)
- Nicolette C Ross
- Torrey Pines Institute for Molecular Studies, Port St Lucie, FL 34987, USA
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31
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Nunnery JK, Engene N, Byrum T, Cao Z, Jabba SV, Pereira AR, Matainaho T, Murray TF, Gerwick WH. Biosynthetically intriguing chlorinated lipophilic metabolites from geographically distant tropical marine cyanobacteria. J Org Chem 2012; 77:4198-208. [PMID: 22489775 PMCID: PMC3345101 DOI: 10.1021/jo300160e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Five new vinylchlorine-containing metabolites, the lipoamides janthielamide A and kimbeamides A-C and the ketide-extended pyranone kimbelactone A, have been isolated from collections of marine cyanobacteria made in Curaçao and Papua New Guinea. Both janthielamide A and kimbeamide A exhibited moderate sodium channel blocking activity in murine Neuro-2a cells. Consistent with this activity, janthielamide A was also found to antagonize veratridine-induced sodium influx in murine cerebrocortical neurons. These lipoamides represent the newest additions to a relatively rare family of marine cyanobacterial-derived lipoamides and a new structural class of compounds exhibiting neuromodulatory activities from marine cyanobacteria.
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Affiliation(s)
- Joshawna K. Nunnery
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093
| | - Niclas Engene
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093
| | - Tara Byrum
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093
| | - Zhengyu Cao
- Department of Pharmacology, College of Medicine, Creighton University, Omaha, Nebraska 68178
| | - Sairam V. Jabba
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093
| | - Alban R. Pereira
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093
| | - Teatulohi Matainaho
- Discipline of Pharmacology, School of Medicine and Health Sciences, University of Papua New Guinea, National Capital District, Papua New Guinea
| | - Thomas F. Murray
- Department of Pharmacology, College of Medicine, Creighton University, Omaha, Nebraska 68178
| | - William H. Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093
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Jabba SV, Murray TF. Sodium channel activator‐stimulated neuronal development involves BDNF‐TrkB signaling. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1048.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Malloy KL, Suyama TL, Engene N, Debonsi H, Cao Z, Matainaho T, Spadafora C, Murray TF, Gerwick WH. Credneramides A and B: neuromodulatory phenethylamine and isopentylamine derivatives of a vinyl chloride-containing fatty acid from cf. Trichodesmium sp. nov. J Nat Prod 2012; 75:60-6. [PMID: 22148360 PMCID: PMC3336157 DOI: 10.1021/np200611f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Credneramides A (1) and B (2), two vinyl chloride-containing metabolites, were isolated from a Papua New Guinea collection of cf. Trichodesmium sp. nov. and expand a recently described class of vinyl chloride-containing natural products. The precursor fatty acid, credneric acid (3), was isolated from both the aqueous and organic fractions of the parent fraction as well as from another geographically and phylogenetically distinct cyanobacterial collection (Panama). Credneramides A and B inhibited spontaneous calcium oscillations in murine cerebrocortical neurons at low micromolar concentrations (1, IC(50) 4.0 μM; 2, IC(50) 3.8 μM).
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Affiliation(s)
- Karla L. Malloy
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093
| | - Takashi L. Suyama
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093
| | - Niclas Engene
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093
| | - Hosana Debonsi
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093
- FCFRP - Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Zhengyu Cao
- Creighton University School of Medicine, Omaha, NE 68178
| | - Teatulohi Matainaho
- Discipline of Pharmacology, School of Medicine and Health Sciences, University of Papua New Guinea, National Capital District, Papua New Guinea
| | - Carmenza Spadafora
- Instituto de Investigaciones Científicas Avanzados y Sevicios de Alta Tecnología, Center of Celluar Molecular Biology of Diseases, Clayton, Bldg. 219 P.O. Box 7250, Panama 5, Republic of Panama
| | | | - William H. Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093
- Author to whom correspondence should be addressed. Tel: (858) 534-0578. Fax: (858) 534-0529.
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Cao Z, Shafer TJ, Crofton KM, Gennings C, Murray TF. Additivity of pyrethroid actions on sodium influx in cerebrocortical neurons in primary culture. Environ Health Perspect 2011; 119:1239-46. [PMID: 21665567 PMCID: PMC3230403 DOI: 10.1289/ehp.1003394] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Accepted: 06/10/2011] [Indexed: 05/06/2023]
Abstract
BACKGROUND Pyrethroid insecticides bind to voltage-gated sodium channels and modify their gating kinetics, thereby disrupting neuronal function. Although previous work has tested the additivity of pyrethroids in vivo, this has not been assessed directly at the primary molecular target using a functional measure. OBJECTIVES We investigated the potency and efficacy of 11 structurally diverse food-use pyrethroids to evoke sodium (Na+) influx in neurons and tested the hypothesis of dose additivity for a mixture of these same 11 compounds. METHODS We determined pyrethroid-induced increases in Na+ influx in primary cultures of cerebrocortical neurons using the Na+-sensitive dye sodium-binding benzofuran isophthalate (SBFI). Concentration-dependent responses for 11 pyrethroids were determined, and the response to dilutions of a mixture of all 11 compounds at an equimolar mixing ratio was assessed. Additivity was tested assuming a dose-additive model. RESULTS Seven pyrethroids produced concentration-dependent, tetrodotoxin-sensitive Na+ influx. The rank order of potency was deltamethrin > S-bioallethrin > β-cyfluthrin > λ-cyhalothrin > esfenvalerate > tefluthrin > fenpropathrin. Cypermethrin and bifenthrin produced modest increases in Na+ influx, whereas permethrin and resmethrin were inactive. When all 11 pyrethroids were present at an equimolar mixing ratio, their actions on Na+ influx were consistent with a dose-additive model. CONCLUSIONS These data provide in vitro relative potency and efficacy measurements for 7 pyrethroid compounds in intact mammalian neurons. Despite differences in individual compound potencies, we found the action of a mixture of all 11 pyrethroids to be additive when we used an appropriate statistical model. These results are consistent with a previous report of the additivity of pyrethroids in vivo.
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Affiliation(s)
- Zhengyu Cao
- Creighton University, School of Medicine, Department of Pharmacology, Omaha, Nebraska 68178, USA
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Engene N, Choi H, Esquenazi E, Byrum T, Villa FA, Cao Z, Murray TF, Dorrestein PC, Gerwick L, Gerwick WH. Phylogeny-guided isolation of ethyl tumonoate A from the marine cyanobacterium cf. Oscillatoria margaritifera. J Nat Prod 2011; 74:1737-1743. [PMID: 21751786 PMCID: PMC3163041 DOI: 10.1021/np200236c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The evolutionary relationships of cyanobacteria, as inferred by their SSU (16S) rRNA genes, were used as predictors of their potential to produce varied secondary metabolites. The evolutionary relatedness in geographically distant cyanobacterial specimens was then used as a guide for the detection and isolation of new variations of predicted molecules. This phylogeny-guided isolation approach for new secondary metabolites was tested in its capacity to direct the search for specific classes of new natural products from Curaçao marine cyanobacteria. As a result, we discovered ethyl tumonoate A (1), a new tumonoic acid derivative with anti-inflammatory activity and inhibitory activity of calcium oscillations in neocortical neurons.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - William H. Gerwick
- To whom correspondence should be addressed. Tel: (858) 534-0578. Fax: (858) 534-0529.
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Aldrich JV, Kulkarni SS, Senadheera SN, Ross NC, Reilley KJ, Eans SO, Ganno ML, Murray TF, McLaughlin JP. Unexpected opioid activity profiles of analogues of the novel peptide kappa opioid receptor ligand CJ-15,208. ChemMedChem 2011; 6:1739-45. [PMID: 21761566 DOI: 10.1002/cmdc.201100113] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 06/07/2011] [Indexed: 11/09/2022]
Abstract
An alanine scan was performed on the novel κ opioid receptor (KOR) peptide ligand CJ-15,208 to determine which residues contribute to the potent in vivo agonist activity observed for the parent peptide. These cyclic tetrapeptides were synthesized by a combination of solid-phase peptide synthesis of the linear precursors, followed by cyclization in solution. Like the parent peptide, each of the analogues exhibited agonist activity and KOR antagonist activity in an antinociceptive assay in vivo. Unlike the parent peptide, the agonist activity of the potent analogues was mediated predominantly, if not exclusively, by μ opioid receptors (MOR). Thus analogues 2 and 4, in which one of the phenylalanine residues was replaced by alanine, exhibited both potent MOR agonist activity and KOR antagonist activity in vivo. These peptides represent novel lead compounds for the development of peptide-based opioid analgesics.
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Affiliation(s)
- Jane V Aldrich
- Department of Medicinal Chemistry, University of Kansas, 1251 Wescoe Hall Dr., Lawrence, KS 66045, USA.
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George J, Murray TF. Biphasic influence of sodium channel activation on neuronal structural plasticity. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1003.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Joju George
- Department of PharmacologyCreighton University School of MedicineOmahaNE
| | - Thomas F Murray
- Department of PharmacologyCreighton University School of MedicineOmahaNE
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Jabba SV, Murray TF. Sodium channel activator‐induced neurite outgrowth is NMDA receptor dependent and involves a TrkB‐PLCγ‐PI3K‐Akt pathway. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1003.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kelamangalath L, Dravid SM, George J, Aldrich JV, Murray TF. κ-Opioid receptor inhibition of calcium oscillations in spinal cord neurons. Mol Pharmacol 2011; 79:1061-71. [PMID: 21422300 DOI: 10.1124/mol.111.071456] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mouse embryonic spinal cord neurons in culture exhibit spontaneous calcium oscillations from day in vitro (DIV) 6 through DIV 10. Such spontaneous activity in developing spinal cord contributes to maturation of synapses and development of pattern-generating circuits. Here we demonstrate that these calcium oscillations are regulated by κ opioid receptors (KORs). The κ opioid agonist dynorphin (Dyn)-A (1-13) suppressed calcium oscillations in a concentration-dependent manner, and both the nonselective opioid antagonist naloxone and the κ-selective blocker norbinaltorphimine eliminated this effect. The KOR-selective agonist (+)-(5α,7α,8β)-N-methyl-N-[7-(1-pyrrolidinyl)-1-oxaspiro[4.5]dec-8-yl]-benzeneacetamide (U69593) mimicked the effect of Dyn-A (1-13) on calcium oscillations. A κ-specific peptide antagonist, zyklophin, was also able to prevent the suppression of calcium oscillations caused by Dyn-A (1-13). These spontaneous calcium oscillations were blocked by 1 μM tetrodotoxin, indicating that they are action potential-dependent. Although the L-type voltage-gated calcium channel blocker nifedipine did not suppress calcium oscillations, the N-type calcium channel blocker ω-conotoxin inhibited this spontaneous response. Blockers of ionotropic glutamate receptors, 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo(f)quinoxaline and dizocilpine maleate (MK-801), also suppressed calcium oscillations, revealing a dependence on glutamate-mediated signaling. Finally, we have demonstrated expression of KORs in glutamatergic spinal neurons and localization in a presynaptic compartment, consistent with previous reports of KOR-mediated inhibition of glutamate release. The KOR-mediated inhibition of spontaneous calcium oscillations may therefore be a consequence of presynaptic inhibition of glutamate release.
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Pereira AR, Cao Z, Engene N, Soria-Mercado IE, Murray TF, Gerwick WH. Palmyrolide A, an unusually stabilized neuroactive macrolide from Palmyra Atoll cyanobacteria. Org Lett 2010; 12:4490-3. [PMID: 20845912 PMCID: PMC2965064 DOI: 10.1021/ol101752n] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Palmyrolide A (1) is a new neuroactive macrolide isolated from a marine cyanobacterial assemblage composed of Leptolyngbya cf. and Oscillatoria spp. collected from Palmyra Atoll. It features a rare N-methyl enamide and an intriguing t-butyl branch; the latter renders the adjacent lactone ester bond resistant to hydrolysis. Consistent with its significant suppression of calcium influx in cerebrocortical neurons (IC(50) = 3.70 μM), palmyrolide A (1) showed a relatively potent sodium channel blocking activity in neuro-2a cells (IC(50) = 5.2 μM), without appreciable cytotoxicity.
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Affiliation(s)
- Alban R. Pereira
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92037
| | - Zhengyu Cao
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska 68178
| | - Niclas Engene
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92037
| | - Irma E. Soria-Mercado
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92037
- Facultad de Ciencias Marinas, Universidad Autonoma de Baja California, Ensenada, BC, 22830, Mexico
| | - Thomas F. Murray
- Department of Pharmacology, Creighton University School of Medicine, Omaha, Nebraska 68178
| | - William H. Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92037
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Cao Z, Shafer TJ, Murray TF. Mechanisms of pyrethroid insecticide-induced stimulation of calcium influx in neocortical neurons. J Pharmacol Exp Ther 2010; 336:197-205. [PMID: 20881019 DOI: 10.1124/jpet.110.171850] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pyrethroid insecticides bind to voltage-gated sodium channels (VGSCs) and modify their gating kinetics, thereby disrupting neuronal function. Pyrethroids have also been reported to alter the function of other channel types, including activation of voltage-gated calcium channels. Therefore, the present study compared the ability of 11 structurally diverse pyrethroids to evoke Ca(2+) influx in primary cultures of mouse neocortical neurons. Nine pyrethroids (tefluthrin, deltamethrin, λ-cyhalothrin, β-cyfluthrin, esfenvalerate, S-bioallethrin, fenpropathrin, cypermethrin, and bifenthrin) produced concentration-dependent elevations in intracellular calcium concentration ([Ca(2+)](i)) in neocortical neurons. Permethrin and resmethrin were without effect on [Ca(2+)](i). These pyrethroids displayed a range of efficacies on Ca(2+) influx; however, the EC(50) values for active pyrethroids all were within one order of magnitude. Tetrodotoxin blocked increases in [Ca(2+)](i) caused by all nine active pyrethroids, indicating that the effects depended on VGSC activation. The pathways for deltamethrin- and tefluthrin-induced Ca(2+) influx include N-methyl-D-aspartic acid receptors, L-type Ca(2+) channels, and reverse mode of operation of the Na(+)/Ca(2+) exchanger inasmuch as antagonists of these sites blocked deltamethrin-induced Ca(2+) influx. These data demonstrate that pyrethroids stimulate Ca(2+) entry into neurons subsequent to their actions on VGSCs.
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Affiliation(s)
- Zhengyu Cao
- Department of Pharmacology, School of Medicine, Creighton University, Omaha, NE 68178, USA
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Choi H, Pereira AR, Cao Z, Shuman CF, Engene N, Byrum T, Matainaho T, Murray TF, Mangoni A, Gerwick WH. The hoiamides, structurally intriguing neurotoxic lipopeptides from Papua New Guinea marine cyanobacteria. J Nat Prod 2010; 73:1411-21. [PMID: 20687534 PMCID: PMC3227549 DOI: 10.1021/np100468n] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Two related peptide metabolites, one a cyclic depsipeptide, hoiamide B (2), and the other a linear lipopeptide, hoiamide C (3), were isolated from two different collections of marine cyanobacteria obtained in Papua New Guinea. Their structures were elucidated by combining various techniques in spectroscopy, chromatography, and synthetic chemistry. Both metabolites belong to the unique hoiamide structural class, characterized by possessing an acetate extended and S-adenosyl methionine modified isoleucine unit, a central triheterocyclic system comprised of two alpha-methylated thiazolines and one thiazole, and a highly oxygenated and methylated C-15 polyketide unit. In neocortical neurons, the cyclic depsipeptide 2 stimulated sodium influx and suppressed spontaneous Ca(2+) oscillations with EC(50) values of 3.9 microM and 79.8 nM, respectively, while 3 had no significant effects in these assays.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Alfonso Mangoni
- To whom correspondence should be addressed. Tel: (858) 534-0578. Fax: (858) 534-0529. ,
| | - William H. Gerwick
- To whom correspondence should be addressed. Tel: (858) 534-0578. Fax: (858) 534-0529. ,
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Fang WJ, Bennett MA, Murray TF, Aldrich JV. Deletion of Ac-NMePhe(1) from [NMePhe(1) ]arodyn under acidic conditions, part 2: effects of substitutions on pharmacological activity. Biopolymers 2010; 96:103-10. [PMID: 20560148 DOI: 10.1002/bip.21495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Arodyn (Ac[Phe¹,²,³,Arg⁴,D-Ala⁸]Dyn A(1-11)NH₂) is an acetylated dynorphin A (Dyn A) analog that is a potent and selective κ opioid receptor antagonist (Bennett et al., J Med Chem 2002, 45, 5617), and its analog [NMePhe¹]arodyn shows even higher affinity and selectivity for κ opioid receptors (Bennett et al., J Pept Res 2005, 65, 322). However, the latter compound is prone to deletion of the Ac-NMePhe moiety from the N-terminus of the peptide during acidic cleavage as described in the accompanying paper. Several stable analogs of [NMePhe¹]arodyn and [NMePhe¹,Trp³]arodyn where the acetyl group was substituted with a heteroatom-containing group were evaluated for their opioid receptor affinity, selectivity, and efficacy. Methoxycarbonyl derivatives exhibited the highest κ opioid receptor affinity among the analogs. Additional [CH₃OCO-NMePhe¹]arodyn analogs where position 3 was substituted with other aromatic or nonaromatic residues were also evaluated for κ receptor affinity, selectivity, and efficacy. [CH₃OCO-NMePhe¹]arodyn has similar κ opioid receptor affinity as [NMePhe¹]arodyn, retains high κ opioid receptor selectivity, and is a potent κ opioid receptor antagonist.
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Affiliation(s)
- Wei-Jie Fang
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66045, USA
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George J, Murray TF. Sodium channel activator‐induced neuronal development is NMDA receptor dependent and involves a Ca
2+
/calmodulin kinase (CaMK)‐CREB‐BDNF signaling pathway. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.770.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Joju George
- Department of PharmacologyCreighton University School of MedicineOmahaNE
| | - Thomas F Murray
- Department of PharmacologyCreighton University School of MedicineOmahaNE
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Affiliation(s)
| | - William H Gerwick
- Center for Marine Biotechnology and BiomedicineScripps Institution of Oceanography and UCSD Skaggs School of Pharmacy and Pharmaceutical SciencesLa JollaCA
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Cao Z, LePage KT, Frederick MO, Nicolaou KC, Murray TF. Involvement of caspase activation in azaspiracid-induced neurotoxicity in neocortical neurons. Toxicol Sci 2010; 114:323-34. [PMID: 20047973 DOI: 10.1093/toxsci/kfp312] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Azaspiracids (AZAs) are a novel group of marine phycotoxins that have been associated with severe human intoxication. We found that AZA-1 exposure increased lactate dehydrogense (LDH) efflux in murine neocortical neurons. AZA-1 also produced nuclear condensation and stimulated caspase-3 activity with an half maximal effective concentration (EC(50)) value of 25.8 nM. These data indicate that AZA-1 triggers neuronal death in neocortical neurons by both necrotic and apoptotic mechanisms. An evaluation of the structure-activity relationships of AZA analogs on LDH efflux and caspase-3 activation demonstrated that the full structure of AZAs was required to produce necrotic or apoptotic cell death. The similar potencies of AZA-1 to stimulate LDH efflux and caspase-3 activation and the parallel structure-activity relationships of azaspiracid analogs in the two assays are consistent with a common molecular target for both responses. To explore the molecular mechanism for AZA-1-induced neurotoxicity, we assessed the influence of AZA-1 on Ca(2+) homeostasis. AZA-1 suppressed spontaneous Ca(2+) oscillations (EC(50) = 445 nM) in neocortical neurons. A distinct structure-activity profile was found for inhibition of Ca(2+) oscillations where both the full structure as well as analogs containing only the FGHI domain attached to a phenyl glycine methyl ester moiety were potent inhibitors. The molecular targets for inhibition of spontaneous Ca(2+) oscillations and neurotoxicity may therefore differ. The caspase protease inhibitor Z-VAD-FMK produced a complete elimination of AZA-1-induced LDH efflux and nuclear condensation in neocortical neurons. Although the molecular target for AZA-induced neurotoxicity remains to be established, these results demonstrate that the observed neurotoxicity is dependent on a caspase signaling pathway.
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Affiliation(s)
- Zhengyu Cao
- Department of Pharmacology, School of Medicine, Creighton University, Omaha, Nebraska 68178, USA
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Sinha B, Cao Z, Murray TF, Aldrich JV. Discovery of dermorphin-based affinity labels with subnanomolar affinity for mu opioid receptors. J Med Chem 2009; 52:7372-5. [PMID: 19621878 DOI: 10.1021/jm9007592] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of potent electrophilic affinity labels (IC(50) = 0.1-5 nM) containing either a bromoacetamide or isothiocyanate based on the mu opioid receptor (MOR) selective peptide dermorphin were prepared. All four analogues exhibited wash resistant inhibition of [(3)H]DAMGO binding at subnanomolar to nanomolar concentrations, suggesting that these analogues bind covalently to MOR. To our knowledge, these peptides are the highest affinity peptide-based affinity labels for MOR reported to date.
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Affiliation(s)
- Bhaswati Sinha
- Department of Medicinal Chemistry, The University of Kansas, 1251 Wescoe Hall Drive, Lawrence, Kansas 66045, USA
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Soria-Mercado IE, Pereira A, Cao Z, Murray TF, Gerwick WH. Alotamide A, a novel neuropharmacological agent from the marine cyanobacterium Lyngbya bouillonii. Org Lett 2009; 11:4704-7. [PMID: 19754100 DOI: 10.1021/ol901438b] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alotamide A (1), a structurally intriguing cyclic depsipeptide, was isolated from the marine mat-forming cyanobacterium Lyngbya bouillonii collected in Papua New Guinea. It features three contiguous peptidic residues and an unsaturated heptaketide with oxidations and methylations unlike those found in any other marine cyanobacterial metabolite. Pure alotamide A (1) displays an unusual calcium influx activation profile in murine cerebrocortical neurons with an EC50 of 4.18 microM.
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Affiliation(s)
- Irma E Soria-Mercado
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92037, USA
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Pereira A, Cao Z, Murray TF, Gerwick WH. Hoiamide a, a sodium channel activator of unusual architecture from a consortium of two papua new Guinea cyanobacteria. ACTA ACUST UNITED AC 2009; 16:893-906. [PMID: 19716479 DOI: 10.1016/j.chembiol.2009.06.012] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 06/23/2009] [Accepted: 06/26/2009] [Indexed: 11/30/2022]
Abstract
Hoiamide A, a novel bioactive cyclic depsipeptide, was isolated from an environmental assemblage of the marine cyanobacteria Lyngbya majuscula and Phormidium gracile collected in Papua New Guinea. This stereochemically complex metabolite possesses a highly unusual structure, which likely derives from a mixed peptide-polyketide biogenetic origin, and includes a peptidic section featuring an acetate extended and S-adenosyl methionine modified isoleucine moiety, a triheterocyclic fragment bearing two alpha-methylated thiazolines and one thiazole, and a highly oxygenated and methylated C15-polyketide substructure. Pure hoiamide A potently inhibited [(3)H]batrachotoxin binding to voltage-gated sodium channels (IC(50) = 92.8 nM), activated sodium influx (EC(50) = 2.31 microM) in mouse neocortical neurons, and exhibited modest cytotoxicity to cancer cells. Further investigation revealed that hoiamide A is a partial agonist of site 2 on the voltage-gated sodium channel.
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Affiliation(s)
- Alban Pereira
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, 92093, USA
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Jabba SV, Prakash A, Dravid SM, Gerwick WH, Murray TF. Antillatoxin, a novel lipopeptide, enhances neurite outgrowth in immature cerebrocortical neurons through activation of voltage-gated sodium channels. J Pharmacol Exp Ther 2009; 332:698-709. [PMID: 20026674 DOI: 10.1124/jpet.109.161802] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Antillatoxin (ATX) is a structurally novel lipopeptide that activates voltage-gated sodium channels (VGSC) leading to sodium influx in cerebellar granule neurons and cerebrocortical neurons 8 to 9 days in vitro (Li et al., 2001; Cao et al., 2008). However, the precise recognition site for ATX on the VGSC remains to be defined. Inasmuch as elevation of intracellular sodium ([Na(+)](i)) may increase N-methyl-d-aspartate receptor (NMDAR)-mediated Ca(2+) influx, Na(+) may function as a signaling molecule. We hypothesized that ATX may enhance neurite outgrowth in cerebrocortical neurons by elevating [Na(+)](i) and augmenting NMDAR function. ATX (30-100 nM) robustly stimulated neurite outgrowth, and this enhancement was sensitive to the VGSC antagonist, tetrodotoxin. To unambiguously demonstrate the enhancement of NMDA receptor function by ATX, we recorded single-channel currents from cell-attached patches. ATX was found to increase the open probability of NMDA receptors. Na(+)-dependent up-regulation of NMDAR function has been shown to be regulated by Src family kinase (SFK) (Yu and Salter, 1998). The Src kinase inhibitor PP2 abrogated ATX-enhanced neurite outgrowth, suggesting a SFK involvement in this response. ATX-enhanced neurite outgrowth was also inhibited by the NMDAR antagonist, (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801), and the calmodulin-dependent kinase kinase (CaMKK) inhibitor, 1,8-naphthoylene benzimidazole-3-carboxylic acid (STO-609), demonstrating the requirement for NMDAR activation with subsequent downstream engagement of the Ca(2+)-dependent CaMKK pathway. These results with the structurally and mechanistically novel natural product, ATX, confirm and generalize our earlier results with a neurotoxin site 5 ligand. These data suggest that VGSC activators may represent a novel pharmacological strategy to regulate neuronal plasticity through NMDAR-dependent mechanisms.
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Affiliation(s)
- S V Jabba
- Creighton University School of Medicine, Department of Pharmacology, Omaha, NE 68178, USA
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