1
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Leo LM, Al-Zoubi R, Hurst DP, Stephan AP, Zhao P, Tilley DG, Miess E, Schulz S, Abood ME, Reggio PH. The NPXXY Motif Regulates β-Arrestin Recruitment by the CB1 Cannabinoid Receptor. Cannabis Cannabinoid Res 2023; 8:731-748. [PMID: 35792570 PMCID: PMC10589503 DOI: 10.1089/can.2021.0223] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [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] [Indexed: 11/12/2022] Open
Abstract
Background: Activation of signaling effectors by G-protein coupled receptors (GPCRs) depends on different molecular mechanisms triggered by conserved amino acid residues. Although studies have focused on the G-protein signaling state, the mechanism for β-arrestin signaling by CB1 is not yet well defined. Studies have indicated that transmembrane helix 7 (TMH7) and the highly conserved NPXXY motif can be subject to different conformational changes in response to biased ligands and could therefore participate in a molecular mechanism to trigger β-arrestin recruitment. Objective: To investigate the effect of mutations in the NPXXY motif on different signaling pathways activated by the CB1 receptor. Materials and Methods: Point mutations of the NPXXY motif and associated residues were generated in the CB1 receptor using site-directed mutagenesis and transfection into HEK-293 cells. Signaling by wild-type and mutant receptors was analyzed by quantifying inhibition of cAMP, and by β-arrestin recruitment assays. Results: We found that N7.49 and Y7.53 are essential for β-arrestin recruitment by CB1. N7.49A and Y7.53F impair β-arrestin signaling, with no effect on G-protein signaling. We found a regulatory role for residue I2.43; I2.43 interacts with Y7.53, affecting its positioning. Reducing steric bulk at I2.43 (I2.43A) enhances β-arrestin1 recruitment, while introducing a polar residue (I2.43T) reduces β-arrestin recruitment. Conclusions: These findings point to a novel mechanism for β-arrestin recruitment, implicating amino acids in the NPXXY motif as critical for the putative β-arrestin biased conformational state of Class A GPCRs.
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Affiliation(s)
- Luciana M. Leo
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Rufaida Al-Zoubi
- Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, Jordan University of Science & Technology, Irbid, Jordan
| | - Dow P. Hurst
- Chemistry and Biochemistry Department, UNC Greensboro, Greensboro, North Carolina, USA
| | - Anna P. Stephan
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Pingwei Zhao
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Douglas G. Tilley
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Elke Miess
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, Jena, Germany
| | - Stefan Schulz
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, Jena, Germany
| | - Mary E. Abood
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Patricia H. Reggio
- Chemistry and Biochemistry Department, UNC Greensboro, Greensboro, North Carolina, USA
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2
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Kline T, Xu C, Kreitzer FR, Hurst DP, Eldeeb KM, Wager-Miller J, Olivas K, Hepburn SA, Huffman JW, Mackie K, Howlett AC, Reggio P, Stella N. Design, synthesis, and evaluation of substituted alkylindoles that activate G protein-coupled receptors distinct from the cannabinoid CB 1 and CB 2 receptors. Eur J Med Chem 2023; 249:115123. [PMID: 36708677 PMCID: PMC10917149 DOI: 10.1016/j.ejmech.2023.115123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/03/2023] [Accepted: 01/13/2023] [Indexed: 01/27/2023]
Abstract
The alkylindole (AI), WIN55212-2, modulates the activity of several proteins, including cannabinoid receptors 1 and 2 (CB1R, CB2R), and at least additional G protein-coupled receptor (GPCR) that remains uncharacterized with respect to its molecular identity and pharmacological profile. Evidence suggests that such AI-sensitive GPCRs are expressed by the human kidney cell line HEK293. We synthesized fourteen novel AI analogues and evaluated their activities at AI-sensitive GPCRs using [35S]GTPγS and [3H]WIN55212-2 binding in HEK293 cell membranes, and performed in silico pharmacophore modeling to identify characteristics that favor binding to AI-sensitive GPCRs versus CB1R/CB2R. Compounds 10 and 12 stimulated [35S]GTPγS binding (EC50s = 3.5 and 1.1 nM, respectively), and this response was pertussis toxin-sensitive, indicating that AI-sensitive GPCRs couple to Gi/o proteins. Five AI analogues reliably distinguished two binding sites that correspond to the high and low affinity state of AI-sensitive GPCRs coupled or not to G proteins. In silico pharmacophore modeling suggest 3 characteristics that favor binding to AI-sensitive GPCRs versus CB1R/CB2R: 1) an s-cis orientation of the two aromatic rings in AI analogues, 2) a narrow dihedral angle between the carbonyl group and the indole ring plane [i.e., O-C(carbonyl)-C3-C2] and 3) the presence of a carbonyl oxygen. The substituted alkylindoles reported here represent novel chemical tools to study AI-sensitive GPCRs.
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Affiliation(s)
- Toni Kline
- Department of Microbiology, University of Washington, Seattle, WA, 98195, USA
| | - Cong Xu
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA
| | - Faith R Kreitzer
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA
| | - Dow P Hurst
- Department of Chemistry and Biochemistry, University of North Carolina, Greensboro, NC, 27412, USA
| | - Khalil M Eldeeb
- Department of Physiology and Pharmacology, Wake Forest University, School of Medicine, Winston-Salem, NC, 27157, USA
| | - Jim Wager-Miller
- Department of Psychological and Brain Sciences and the Gill Center, Indiana University, Bloomington, IN, 47405, USA
| | - Kathleen Olivas
- Department of Microbiology, University of Washington, Seattle, WA, 98195, USA
| | - Seon A Hepburn
- Howard L. Hunter Laboratory, Clemson University, Clemson, SC, 29634, USA
| | - John W Huffman
- Howard L. Hunter Laboratory, Clemson University, Clemson, SC, 29634, USA
| | - Ken Mackie
- Department of Psychological and Brain Sciences and the Gill Center, Indiana University, Bloomington, IN, 47405, USA
| | - Allyn C Howlett
- Department of Physiology and Pharmacology, Wake Forest University, School of Medicine, Winston-Salem, NC, 27157, USA
| | - Patricia Reggio
- Department of Chemistry and Biochemistry, University of North Carolina, Greensboro, NC, 27412, USA
| | - Nephi Stella
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA; Department of Psychiatry & Behavioral Sciences, University of Washington, Seattle, WA, 98195, USA.
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3
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Figuerola-Asencio L, Morales P, Zhao P, Hurst DP, Sayed SS, Colón KL, Gómez-Cañas M, Fernández-Ruiz J, Croatt MP, Reggio PH, Abood ME, Jagerovic N. Thienopyrimidine Derivatives as GPR55 Receptor Antagonists: Insight into Structure-Activity Relationship. ACS Med Chem Lett 2022; 14:18-25. [PMID: 36655130 PMCID: PMC9841585 DOI: 10.1021/acsmedchemlett.2c00325] [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: 07/14/2022] [Accepted: 11/22/2022] [Indexed: 12/05/2022] Open
Abstract
GPR55 is an orphan G-protein coupled receptor involved in various pathophysiological conditions. However, there are only a few noncannabinoid GPR55 ligands reported so far. The lack of potent and selective GPR55 ligands precludes a deep exploration of this receptor. The studies presented here focused on a thienopyrimidine scaffold based on the GPR55 antagonist ML192, previously discovered by high-throughput screening. The GPR55 activities of the new synthesized compounds were assessed using β-arrestin recruitment assays in Chinese hamster ovary cells overexpressing human GPR55. Some derivatives were identified as GPR55 antagonists with functional efficacy and selectivity versus CB1 and CB2 cannabinoid receptors.
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Affiliation(s)
- Laura Figuerola-Asencio
- Instituto
de Química Médica, Consejo
Superior de Investigaciones Científicas, 28006Madrid, Spain
| | - Paula Morales
- Instituto
de Química Médica, Consejo
Superior de Investigaciones Científicas, 28006Madrid, Spain
| | - Pingwei Zhao
- Center
for Substance Abuse Research, Temple University, Philadelphia, Pennsylvania19122, United States
| | - Dow P. Hurst
- Center
for Drug Discovery, Department of Chemistry and Biochemistry, University North Carolina, Greensboro, North Carolina27599, United States
| | - Sommayah S. Sayed
- Center
for Drug Discovery, Department of Chemistry and Biochemistry, University North Carolina, Greensboro, North Carolina27599, United States
| | - Katsuya L. Colón
- Center
for Drug Discovery, Department of Chemistry and Biochemistry, University North Carolina, Greensboro, North Carolina27599, United States
| | - María Gómez-Cañas
- Department
of Biochemistry and Molecular Biology, Faculty of Medicine, Complutense University, CIBERNED and IRYCIS, 28040Madrid, Spain
| | - Javier Fernández-Ruiz
- Department
of Biochemistry and Molecular Biology, Faculty of Medicine, Complutense University, CIBERNED and IRYCIS, 28040Madrid, Spain
| | - Mitchell P. Croatt
- Center
for Drug Discovery, Department of Chemistry and Biochemistry, University North Carolina, Greensboro, North Carolina27599, United States
| | - Patricia H. Reggio
- Center
for Drug Discovery, Department of Chemistry and Biochemistry, University North Carolina, Greensboro, North Carolina27599, United States,E-mail:
| | - Mary E. Abood
- Center
for Substance Abuse Research, Temple University, Philadelphia, Pennsylvania19122, United States,E-mail:
| | - Nadine Jagerovic
- Instituto
de Química Médica, Consejo
Superior de Investigaciones Científicas, 28006Madrid, Spain,E-mail:
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4
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Brandt AL, Garai S, Zagzoog A, Hurst DP, Stevenson LA, Pertwee RG, Imler GH, Reggio PH, Thakur GA, Laprairie RB. Pharmacological evaluation of enantiomerically separated positive allosteric modulators of cannabinoid 1 receptor, GAT591 and GAT593. Front Pharmacol 2022; 13:919605. [PMID: 36386195 PMCID: PMC9640980 DOI: 10.3389/fphar.2022.919605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 04/13/2022] [Accepted: 10/07/2022] [Indexed: 11/09/2023] Open
Abstract
Positive allosteric modulation of the type 1 cannabinoid receptor (CB1R) has substantial potential to treat both neurological and immune disorders. To date, a few studies have evaluated the structure-activity relationship (SAR) for CB1R positive allosteric modulators (PAMs). In this study, we separated the enantiomers of the previously characterized two potent CB1R ago-PAMs GAT591 and GAT593 to determine their biochemical activity at CB1R. Separating the enantiomers showed that the R-enantiomers (GAT1665 and GAT1667) displayed mixed allosteric agonist-PAM activity at CB1R while the S-enantiomers (GAT1664 and GAT1666) showed moderate activity. Furthermore, we observed that the R and S-enantiomers had distinct binding sites on CB1R, which led to their distinct behavior both in vitro and in vivo. The R-enantiomers (GAT1665 and GAT1667) produced ago-PAM effects in vitro, and PAM effects in the in vivo behavioral triad, indicating that the in vivo activity of these ligands may occur via PAM rather than agonist-based mechanisms. Overall, this study provides mechanistic insight into enantiospecific interaction of 2-phenylindole class of CB1R allosteric modulators, which have shown therapeutic potential in the treatment of pain, epilepsy, glaucoma, and Huntington's disease.
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Affiliation(s)
- Asher L. Brandt
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
| | - Sumanta Garai
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Boston, MA, United States
| | - Ayat Zagzoog
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
| | - Dow P. Hurst
- Center for Drug Discovery, University of North Carolina Greensboro, Greensboro, NC, United States
| | - Lesley A. Stevenson
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Roger G. Pertwee
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Gregory H. Imler
- Centre for Biomolecular Science and Engineering, Naval Research Laboratory, Washington, DC, United States
| | - Patricia H. Reggio
- Center for Drug Discovery, University of North Carolina Greensboro, Greensboro, NC, United States
| | - Ganesh A. Thakur
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Boston, MA, United States
| | - Robert B. Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
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5
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Abstract
The capsaicin receptor, transient receptor potential vanilloid type 1 (TRPV1), is a polymodal channel that has been implicated in the perception of pain and can be modulated by a variety of cannabinoid ligands. Here we report TRPV1 channel activation by the endocannabinoid, anandamide (AEA), in a unique, peripheral binding site via extended MD simulations. These results aim to expand the understanding of TRPV1 and assist in the development of new TRPV1 modulators.
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Affiliation(s)
- Chanté Muller
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina 27412, United States
| | - Diane L Lynch
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina 27412, United States
| | - Dow P Hurst
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina 27412, United States
| | - Patricia H Reggio
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina 27412, United States
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6
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Garai S, Leo LM, Szczesniak AM, Hurst DP, Schaffer PC, Zagzoog A, Black T, Deschamps JR, Miess E, Schulz S, Janero DR, Straiker A, Pertwee RG, Abood ME, Kelly MEM, Reggio PH, Laprairie RB, Thakur GA. Discovery of a Biased Allosteric Modulator for Cannabinoid 1 Receptor: Preclinical Anti-Glaucoma Efficacy. J Med Chem 2021; 64:8104-8126. [PMID: 33826336 DOI: 10.1021/acs.jmedchem.1c00040] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [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: 12/13/2022]
Abstract
We apply the magic methyl effect to improve the potency/efficacy of GAT211, the prototypic 2-phenylindole-based cannabinoid type-1 receptor (CB1R) agonist-positive allosteric modulator (ago-PAM). Introducing a methyl group at the α-position of nitro group generated two diastereomers, the greater potency and efficacy of erythro, (±)-9 vs threo, (±)-10 constitutes the first demonstration of diastereoselective CB1R-allosteric modulator interaction. Of the (±)-9 enantiomers, (-)-(S,R)-13 evidenced improved potency over GAT211 as a CB1R ago-PAM, whereas (+)-(R,S)-14 was a CB1R allosteric agonist biased toward G protein- vs β-arrestin1/2-dependent signaling. (-)-(S,R)-13 and (+)-(R,S)-14 were devoid of undesirable side effects (triad test), and (+)-(R,S)-14 reduced intraocular pressure with an unprecedentedly long duration of action in a murine glaucoma model. (-)-(S,R)-13 docked into both a CB1R extracellular PAM and intracellular allosteric-agonist site(s), whereas (+)-(R,S)-14 preferentially engaged only the latter. Exploiting G-protein biased CB1R-allosteric modulation can offer safer therapeutic candidates for glaucoma and, potentially, other diseases.
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Affiliation(s)
- Sumanta Garai
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Luciana M Leo
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Anna-Maria Szczesniak
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Dow P Hurst
- Center for Drug Discovery, University of North Carolina Greensboro, Greensboro, North Carolina 27402, United States
| | - Peter C Schaffer
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Ayat Zagzoog
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, Saskatchewan S7N2Z4, Canada
| | - Tallan Black
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, Saskatchewan S7N2Z4, Canada
| | - Jeffrey R Deschamps
- Naval Research Laboratory, Code 6930, 4555 Overlook Avenue, Washington, District of Columbia 20375, United States
| | - Elke Miess
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany
| | - Stefan Schulz
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany
| | - David R Janero
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Alex Straiker
- The Gill Center and the Department of Psychological & Brain Sciences, Indiana University, 1101 E. 10th St, Bloomington, Indiana 47405, United States
| | - Roger G Pertwee
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, U.K
| | - Mary E Abood
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Melanie E M Kelly
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Patricia H Reggio
- Center for Drug Discovery, University of North Carolina Greensboro, Greensboro, North Carolina 27402, United States
| | - Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, Saskatchewan S7N2Z4, Canada
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
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7
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Morales P, Lago-Fernandez A, Hurst DP, Sotudeh N, Brailoiu E, Reggio PH, Abood ME, Jagerovic N. Therapeutic Exploitation of GPR18: Beyond the Cannabinoids? J Med Chem 2020; 63:14216-14227. [PMID: 32914978 DOI: 10.1021/acs.jmedchem.0c00926] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [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]
Abstract
GPR18 is a G-protein-coupled receptor that belongs to the orphan class A family. Even though it shares low sequence homology with the cannabinoid receptors CB1R and CB2R, a growing body of research suggests its relationship with the endocannabinoid system, not only because it is able to recognize cannabinoid ligands but also because of its expression and ability to heteromerize with CBRs. In this review, we aim to analyze the biological relevance, reported modulators, and structural features of GPR18. In order to guide future drug design in this field, highlights from molecular modeling of GPR18 will be provided.
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Affiliation(s)
- Paula Morales
- Instituto de Química Médica, CSIC, Calle Juan de la Cierva, 3, 28006 Madrid, Spain
| | - Ana Lago-Fernandez
- Instituto de Química Médica, CSIC, Calle Juan de la Cierva, 3, 28006 Madrid, Spain
| | - Dow P Hurst
- Chemistry and Biochemistry Department, UNC Greensboro, 1400 Spring Garden Street, Greensboro, North Carolina 27412, United States
| | - Noori Sotudeh
- Chemistry and Biochemistry Department, UNC Greensboro, 1400 Spring Garden Street, Greensboro, North Carolina 27412, United States
| | - Eugen Brailoiu
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, Pennsylvania 19140, United States
| | - Patricia H Reggio
- Chemistry and Biochemistry Department, UNC Greensboro, 1400 Spring Garden Street, Greensboro, North Carolina 27412, United States
| | - Mary E Abood
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, Pennsylvania 19140, United States
| | - Nadine Jagerovic
- Instituto de Química Médica, CSIC, Calle Juan de la Cierva, 3, 28006 Madrid, Spain
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8
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Abstract
In this issue of Cell, two papers report agonist-bound cryo-EM structures of the cannabinoid receptor, CB2, in complex with Gi. Importantly, beyond providing information that could help distinguish CB2 ligand binding from CB1, these structures support the existence of a nucleotide-free state during G-protein signaling.
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Affiliation(s)
- Diane L Lynch
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA
| | - Dow P Hurst
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA
| | - Patricia H Reggio
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA.
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9
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Abstract
The transient receptor potential subfamily vanilloid type 1 ion channel (TRPV1), located in the peripheral nervous system has been implicated in the perception of pain and possesses the ability to be modulated by various cannabinoid ligands. Because of its location, TRPV1 is an ideal target for the development of novel pain therapeutics. Literature precedent suggests a wide range of cannabinoid ligands can activate TRPV1, but the location and mode of entry is not well understood. Understanding the modes in which cannabinoids can enter and bind to TRPV1 can aid in rational drug design. The first endogenous ligand identified for TRPV1 was the endocannabinoid, anandamide (AEA). The Molecular Dynamics (MD) studies discussed here investigate the entry mode of AEA into TRPV1. During the course of the 10+ microsecond MD simulations, two distinct binding modes were observed: AEA binding in the tunnel formed by the S1–S4 region, and AEA binding in the vanilloid binding pocket, with preference for the former. Unbiased MD simulations have revealed multiple spontaneous binding events into the S1–S4 region, with only one event of AEA binding the vanilloid binding pocket. These results suggest that AEA enters TRPV1 via a novel location between helices S1–S4 via the lipid bilayer.
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Affiliation(s)
- Chante Muller
- Chemisty and Biochemistry Department, UNC Greensboro, Greensboro, NC, United States
| | - Diane L Lynch
- Chemisty and Biochemistry Department, UNC Greensboro, Greensboro, NC, United States
| | - Dow P Hurst
- Chemisty and Biochemistry Department, UNC Greensboro, Greensboro, NC, United States
| | - Patricia H Reggio
- Chemisty and Biochemistry Department, UNC Greensboro, Greensboro, NC, United States
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10
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Isawi IH, Morales P, Sotudeh N, Hurst DP, Lynch DL, Reggio PH. GPR6 Structural Insights: Homology Model Construction and Docking Studies. Molecules 2020; 25:molecules25030725. [PMID: 32046081 PMCID: PMC7037797 DOI: 10.3390/molecules25030725] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 12/31/2019] [Revised: 02/01/2020] [Accepted: 02/04/2020] [Indexed: 01/14/2023] Open
Abstract
GPR6 is an orphan G protein-coupled receptor that has been associated with the cannabinoid family because of its recognition of a sub-set of cannabinoid ligands. The high abundance of GPR6 in the central nervous system, along with high constitutive activity and a link to several neurodegenerative diseases make GPR6 a promising biological target. In fact, diverse research groups have demonstrated that GPR6 represents a possible target for the treatment of neurodegenerative disorders such as Parkinson's disease, Alzheimer's disease, and Huntington's disease. Several patents have claimed the use of a wide range of pyrazine derivatives as GPR6 inverse agonists for the treatment of Parkinson's disease symptoms and other dyskinesia syndromes. However, the full pharmacological importance of GPR6 has not yet been fully explored due to the lack of high potency, readily available ligands targeting GPR6. The long-term goal of the present study is to develop such ligands. In this paper, we describe our initial steps towards this goal. A human GPR6 homology model was constructed using a suite of computational techniques. This model permitted the identification of unique GPR6 structural features and the exploration of the GPR6 binding crevice. A subset of patented pyrazine analogs were docked in the resultant GPR6 inactive state model to validate the model, rationalize the structure-activity relationships from the reported patents and identify the key residues in the binding crevice for ligand recognition. We will take this structural knowledge into the next phase of GPR6 project, in which scaffold hopping will be used to design new GPR6 ligands.
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Affiliation(s)
- Israa H. Isawi
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA; (I.H.I.); (D.P.H.); (D.L.L.)
| | - Paula Morales
- Instituto de Química Medica (IQM-CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain;
| | - Noori Sotudeh
- Department of Physiology and Biophysics, The State University of New York at Buffalo, Buffalo, NY 14260, USA;
| | - Dow P. Hurst
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA; (I.H.I.); (D.P.H.); (D.L.L.)
| | - Diane L. Lynch
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA; (I.H.I.); (D.P.H.); (D.L.L.)
| | - Patricia H. Reggio
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27412, USA; (I.H.I.); (D.P.H.); (D.L.L.)
- Correspondence:
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11
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Isawi I, Morales P, Hurst DP, Lynch DL, Reggio PH. Constructing GPR6 Homology Model, Docking Studies and Drug Design. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.2838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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12
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Garai S, Kulkarni PM, Schaffer PC, Leo LM, Brandt AL, Zagzoog A, Black T, Lin X, Hurst DP, Janero DR, Abood ME, Zimmowitch A, Straiker A, Pertwee RG, Kelly M, Szczesniak AM, Denovan-Wright EM, Mackie K, Hohmann AG, Reggio PH, Laprairie RB, Thakur GA. Application of Fluorine- and Nitrogen-Walk Approaches: Defining the Structural and Functional Diversity of 2-Phenylindole Class of Cannabinoid 1 Receptor Positive Allosteric Modulators. J Med Chem 2020; 63:542-568. [PMID: 31756109 DOI: 10.1021/acs.jmedchem.9b01142] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cannabinoid 1 receptor (CB1R) allosteric ligands hold a far-reaching therapeutic promise. We report the application of fluoro- and nitrogen-walk approaches to enhance the drug-like properties of GAT211, a prototype CB1R allosteric agonist-positive allosteric modulator (ago-PAM). Several analogs exhibited improved functional potency (cAMP, β-arrestin 2), metabolic stability, and aqueous solubility. Two key analogs, GAT591 (6r) and GAT593 (6s), exhibited augmented allosteric-agonist and PAM activities in neuronal cultures, improved metabolic stability, and enhanced orthosteric agonist binding (CP55,940). Both analogs also exhibited good analgesic potency in the CFA inflammatory-pain model with longer duration of action over GAT211 while being devoid of adverse cannabimimetic effects. Another analog, GAT592 (9j), exhibited moderate ago-PAM potency and improved aqueous solubility with therapeutic reduction of intraocular pressure in murine glaucoma models. The SAR findings and the enhanced allosteric activity in this class of allosteric modulators were accounted for in our recently developed computational model for CB1R allosteric activation and positive allosteric modulation.
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Affiliation(s)
- Sumanta Garai
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Pushkar M Kulkarni
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Peter C Schaffer
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Luciana M Leo
- Center for Substance Abuse Research, Lewis Katz School of Medicine , Temple University , Philadelphia , Pennsylvania 19140 , United States
| | - Asher L Brandt
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada
| | - Ayat Zagzoog
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada
| | - Tallan Black
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada
| | - Xiaoyan Lin
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Dow P Hurst
- Center for Drug Discovery , University of North Carolina Greensboro , Greensboro , North Carolina 27402 , United States
| | - David R Janero
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Department of Chemistry and Chemical Biology, College of Science, and Health Sciences Entrepreneurs , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Mary E Abood
- Center for Substance Abuse Research, Lewis Katz School of Medicine , Temple University , Philadelphia , Pennsylvania 19140 , United States
| | - Anaelle Zimmowitch
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Alex Straiker
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Roger G Pertwee
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences , University of Aberdeen , Aberdeen AB25 2ZD , Scotland, U.K
| | - Melanie Kelly
- Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Anna-Maria Szczesniak
- Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Eileen M Denovan-Wright
- Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Ken Mackie
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Andrea G Hohmann
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Patricia H Reggio
- Center for Drug Discovery , University of North Carolina Greensboro , Greensboro , North Carolina 27402 , United States
| | - Robert B Laprairie
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada.,Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
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13
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Hurst DP, Garai S, Kulkarni PM, Schaffer PC, Reggio PH, Thakur GA. Identification of CB1 Receptor Allosteric Sites Using Force-Biased MMC Simulated Annealing and Validation by Structure-Activity Relationship Studies. ACS Med Chem Lett 2019; 10:1216-1221. [PMID: 31413808 DOI: 10.1021/acsmedchemlett.9b00256] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 07/10/2019] [Indexed: 02/02/2023] Open
Abstract
Positive allosteric modulation of the cannabinoid 1 receptor (CB1R) has demonstrated distinct therapeutic advantages that address several limitations associated with orthosteric agonism and has opened a promising therapeutic avenue for further drug development. To advance the development of CB1R positive allosteric modulators, it is important to understand the molecular architecture of CB1R allosteric site(s). The goal of this work was to use Force-Biased MMC Simulated Annealing to identify binding sites for GAT228 (R), a partial allosteric agonist, and GAT229 (S), a positive allosteric modulator (PAM) at the CB1R. Our studies suggest that GAT228 binds in an intracellular (IC) TMH1-2-4 exosite that would allow this compound to act as a CB1 allosteric agonist as well as a CB1 PAM. In contrast, GAT229 binds at the extracellular (EC) ends of TMH2/3, just beneath the EC1 loop. At this site, this compound can act as CB1 PAM only. Finally, these results were successfully validated through the synthesis and biochemical evaluation of a focused library of compounds.
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Affiliation(s)
- Dow P. Hurst
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro North Carolina 27412, United States
| | - Sumanta Garai
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Pushkar M. Kulkarni
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Peter C. Schaffer
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Patricia H. Reggio
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro North Carolina 27412, United States
| | - Ganesh A. Thakur
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
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14
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Yeliseev A, Nickels JD, Hines KG, Zoubak L, Teague WE, Lynch DL, Hurst DP, Weiss KL, Katsaras J, Reggio PH, Gawrisch K. Cannabinoid Receptor CB2 Oligomerization in a Lipid Matrix. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.1288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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15
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Ragusa G, Bencivenni S, Morales P, Callaway T, Hurst DP, Asproni B, Merighi S, Loriga G, Pinna GA, Reggio PH, Gessi S, Murineddu G. Synthesis, Pharmacological Evaluation, and Docking Studies of Novel Pyridazinone-Based Cannabinoid Receptor Type 2 Ligands. ChemMedChem 2018; 13:1102-1114. [PMID: 29575721 DOI: 10.1002/cmdc.201800152] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Indexed: 11/12/2022]
Abstract
In recent years, cannabinoid type 2 receptors (CB2 R) have emerged as promising therapeutic targets in a wide variety of diseases. Selective ligands of CB2 R are devoid of the psychoactive effects typically observed for CB1 R ligands. Based on our recent studies on a class of pyridazinone 4-carboxamides, further structural modifications of the pyridazinone core were made to better investigate the structure-activity relationships for this promising scaffold with the aim to develop potent CB2 R ligands. In binding assays, two of the new synthesized compounds [6-(3,4-dichlorophenyl)-2-(4-fluorobenzyl)-cis-N-(4-methylcyclohexyl)-3-oxo-2,3-dihydropyridazine-4-carboxamide (2) and 6-(4-chloro-3-methylphenyl)-cis-N-(4-methylcyclohexyl)-3-oxo-2-pentyl-2,3-dihydropyridazine-4-carboxamide (22)] showed high CB2 R affinity, with Ki values of 2.1 and 1.6 nm, respectively. In addition, functional assays of these compounds and other new active related derivatives revealed their pharmacological profiles as CB2 R inverse agonists. Compound 22 displayed the highest CB2 R selectivity and potency, presenting a favorable in silico pharmacokinetic profile. Furthermore, a molecular modeling study revealed how 22 produces inverse agonism through blocking the movement of the toggle-switch residue, W6.48.
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Affiliation(s)
- Giulio Ragusa
- Department of Chemistry and Pharmacy, University of Sassari, via F. Muroni 23/A, 07100, Sassari, Italy
| | - Serena Bencivenni
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università di Ferrara, Via Fossato di Mortara, 17-19, 44121, Ferrara, Italy
| | - Paula Morales
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
| | - Tyra Callaway
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
| | - Dow P Hurst
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
| | - Battistina Asproni
- Department of Chemistry and Pharmacy, University of Sassari, via F. Muroni 23/A, 07100, Sassari, Italy
| | - Stefania Merighi
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università di Ferrara, Via Fossato di Mortara, 17-19, 44121, Ferrara, Italy
| | - Giovanni Loriga
- Institute of Translational Pharmacology, National Research Council, 09010 Pula, Cagliari, Italy
| | - Gerard A Pinna
- Department of Chemistry and Pharmacy, University of Sassari, via F. Muroni 23/A, 07100, Sassari, Italy
| | - Patricia H Reggio
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA
| | - Stefania Gessi
- Dipartimento di Scienze Mediche, Sezione di Farmacologia, Università di Ferrara, Via Fossato di Mortara, 17-19, 44121, Ferrara, Italy
| | - Gabriele Murineddu
- Department of Chemistry and Pharmacy, University of Sassari, via F. Muroni 23/A, 07100, Sassari, Italy
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16
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Abstract
The Reggio group has constructed computer models of the inactive and G-protein-activated states of the cannabinoid CB1 and CB2 receptors, as well as, several orphan receptors that recognize a subset of cannabinoid compounds, including GPR55 and GPR18. These models have been used to design ligands, mutations, and covalent labeling studies. The resultant second-generation models have been used to design ligands with improved affinity, efficacy, and subtype selectivity. Herein, we provide a guide for the development of GPCR models using the most recent orphan receptor studied in our lab, GPR3. GPR3 is an orphan receptor that belongs to the Class A family of G-protein-coupled receptors. It shares high sequence similarity with GPR6, GPR12, the lysophospholipid receptors, and the cannabinoid receptors. GPR3 is predominantly expressed in mammalian brain and oocytes and it is known as a Gαs-coupled receptor activated constitutively in cells. GPR3 represents a possible target for the treatment of different pathological conditions such as Alzheimer's disease, oocyte maturation, or neuropathic pain. However, the lack of potent and selective GPR3 ligands is delaying the exploitation of this promising therapeutic target. In this context, we aim to develop a homology model that helps us to elucidate the structural determinants governing ligand-receptor interactions at GPR3. In this chapter, we detail the methods and rationale behind the construction of the GPR3 active-and inactive-state models. These homology models will enable the rational design of novel ligands, which may serve as research tools for further understanding of the biological role of GPR3.
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Affiliation(s)
- Paula Morales
- University of North Carolina at Greensboro, Greensboro, NC, United States.
| | - Dow P Hurst
- University of North Carolina at Greensboro, Greensboro, NC, United States
| | - Patricia H Reggio
- University of North Carolina at Greensboro, Greensboro, NC, United States
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17
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Abstract
The cannabinoid type 1 and 2 G-protein-coupled receptors are currently important pharmacological targets with significant drug discovery potential. These receptors have been shown to display functional selectivity or biased agonism, a property currently thought to have substantial therapeutic potential. Although recent advances in crystallization techniques have provided a wealth of structural information about this important class of membrane-embedded proteins, these structures lack dynamical information. In order to fully understand the interplay of structure and function for this important class of proteins, complementary techniques that address the dynamical aspects of their function are required such as NMR as well as a variety of other spectroscopies. Complimentary to these experimental approaches is molecular dynamics, which has been effectively used to help unravel, at the atomic level, the dynamics of ligand binding and activation of these membrane-bound receptors. Here, we discuss and present several representative examples of the application of molecular dynamics simulations to the understanding of the signatures of ligand-binding and -biased signaling at the cannabinoid type 1 and 2 receptors.
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Affiliation(s)
- Diane L Lynch
- University of North Carolina at Greensboro, Greensboro, NC, United States.
| | - Dow P Hurst
- University of North Carolina at Greensboro, Greensboro, NC, United States
| | - Derek M Shore
- University of North Carolina at Greensboro, Greensboro, NC, United States
| | - Mike C Pitman
- University of North Carolina at Greensboro, Greensboro, NC, United States
| | - Patricia H Reggio
- University of North Carolina at Greensboro, Greensboro, NC, United States
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18
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Morales P, Hurst DP, Reggio PH. Construction of a GPR3 Homology Model Using Conformational Memories. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.1939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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19
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Lingerfelt MA, Zhao P, Sharir HP, Hurst DP, Reggio PH, Abood ME. Identification of Crucial Amino Acid Residues Involved in Agonist Signaling at the GPR55 Receptor. Biochemistry 2017; 56:473-486. [PMID: 28005346 PMCID: PMC5338039 DOI: 10.1021/acs.biochem.6b01013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [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: 12/16/2022]
Abstract
GPR55 is a newly deorphanized class A G-protein-coupled receptor that has been implicated in inflammatory pain, neuropathic pain, metabolic disorder, bone development, and cancer. Few potent GPR55 ligands have been identified to date. This is largely due to an absence of information about salient features of GPR55, such as residues important for signaling and residues implicated in the GPR55 signaling cascade. The goal of this work was to identify residues that are key for the signaling of the GPR55 endogenous ligand, l-α-lysophosphatidylinositol (LPI), as well as the signaling of the GPR55 agonist, ML184 {CID 2440433, 3-[4-(2,3-dimethylphenyl)piperazine-1-carbonyl]-N,N-dimethyl-4-pyrrolidin-1-ylbenzenesulfonamide}. Serum response element (SRE) and serum response factor (SRF) luciferase assays were used as readouts for studying LPI and ML184 signaling at the GPR55 mutants. A GPR55 R* model based on the recent δ-opioid receptor (DOR) crystal structure was used to interpret the resultant mutation data. Two residues were found to be crucial for agonist signaling at GPR55, K2.60 and E3.29, suggesting that these residues form the primary interaction site for ML184 and LPI at GPR55. Y3.32F, H(170)F, and F6.55A/L mutation results suggested that these residues are part of the orthosteric binding site for ML184, while Y3.32F and H(170)F mutation results suggest that these two residues are part of the LPI binding pocket. Y3.32L, M3.36A, and F6.48A mutation results suggest the importance of a Y3.32/M3.36/F6.48 cluster in the GPR55 signaling cascade. C(10)A and C(260)A mutations suggest that these residues form a second disulfide bridge in the extracellular domain of GPR55, occluding ligand extracellular entry in the TMH1-TMH7 region of GPR55. Taken together, these results provide the first set of discrete information about GPR55 residues important for LPI and ML184 signaling and for GPR55 activation. This information should aid in the rational design of next-generation GPR55 ligands and the creation of the first high-affinity GPR55 radioligand, a tool that is sorely needed in the field.
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MESH Headings
- Amino Acid Motifs
- Binding Sites
- Crystallography, X-Ray
- Gene Expression
- HEK293 Cells
- Humans
- Kinetics
- Ligands
- Lysophospholipids/chemistry
- Lysophospholipids/pharmacology
- Molecular Docking Simulation
- Mutation
- Piperazines/chemistry
- Piperazines/pharmacology
- Protein Binding
- Pyrrolidines/chemistry
- Pyrrolidines/pharmacology
- Receptors, Cannabinoid
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Opioid, delta/chemistry
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/metabolism
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Serum Response Element
- Serum Response Factor/chemistry
- Serum Response Factor/genetics
- Serum Response Factor/metabolism
- Signal Transduction
- Glycine max
- Structural Homology, Protein
- Thermodynamics
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Affiliation(s)
- Mary A. Lingerfelt
- Department of Chemistry and Biochemistry, UNC-Greensboro, Greensboro, North Carolina 27402 United States
| | - Pingwei Zhao
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Haleli P. Sharir
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Dow P. Hurst
- Department of Chemistry and Biochemistry, UNC-Greensboro, Greensboro, North Carolina 27402 United States
| | - Patricia H. Reggio
- Department of Chemistry and Biochemistry, UNC-Greensboro, Greensboro, North Carolina 27402 United States
| | - Mary E. Abood
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania 19140, United States
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20
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Abdalhameed MM, Zhao P, Hurst DP, Reggio PH, Abood ME, Croatt MP. Structure-activity relationships of benzothiazole GPR35 antagonists. Bioorg Med Chem Lett 2016; 27:612-615. [PMID: 27989666 DOI: 10.1016/j.bmcl.2016.12.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/01/2016] [Accepted: 12/02/2016] [Indexed: 11/16/2022]
Abstract
The first structure-activity relationships for a benzothiazole scaffold acting as an antagonist at GPR35 is presented. Analogues were designed based on a lead compound that was previously determined to have selective activity as a GPR35 antagonist. The synthetic route was modular in nature to independently explore the role of the middle and both ends of the scaffold. The activities of the analogues illustrate the importance of all three segments of the compound.
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Affiliation(s)
- Manahil M Abdalhameed
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, NC 27402, United States
| | - Pingwei Zhao
- Department of Anatomy and Cell Biology and Center for Substance Abuse Research, Temple University, Philadelphia, PA 19140, United States
| | - Dow P Hurst
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, NC 27402, United States
| | - Patricia H Reggio
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, NC 27402, United States.
| | - Mary E Abood
- Department of Anatomy and Cell Biology and Center for Substance Abuse Research, Temple University, Philadelphia, PA 19140, United States.
| | - Mitchell P Croatt
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, NC 27402, United States.
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21
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Ledford C, McMahon M, Whitesell A, Khan G, Kandagatla SK, Hurst DP, Reggio PH, Raner GM. A dual substrate kinetic model for cytochrome P450 BM3-F87G catalysis: simultaneous binding of long chain aldehydes and 4-fluorophenol. Biotechnol Lett 2016; 39:311-321. [PMID: 27864654 DOI: 10.1007/s10529-016-2252-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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: 08/25/2016] [Accepted: 11/03/2016] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To develop a model for binding and catalysis associated with the stimulation of 4-fluorophenol (4-FP) oxidation in the presence of long chain aldehydes by the enzymatic catalyst, cytochrome P450BM3-F87G. RESULTS A variation of the Michaeli-Menten kinetic model was employed to describe interactions at the active site of the enzyme, along with computer aided modeling approaches. In addition to the hydroquinone product arising from de-fluorination of 4-FP, a second product (p-fluorocatechol) was also observed and, like the hydroquinone, its rate of formation increased in the presence of the aldehyde. When only aldehyde was present with the enzyme, BM3-F87G catalyzed its oxidation to the corresponding carboxylic acid; however, this activity was inhibited when 4-FP was added to the reaction. A 3D computer model of the active site containing both aldehyde and 4-FP was generated, guided by these kinetic observations. Finally, partitioning between the two phenolic products was examined with an emphasis on the conditions directing the initial epoxidation at either the 2,3- or 3,4-positions on the substrate. Temperature, reaction time, substrate concentration, and the structure of the aldehyde had no substantial effect on the overall product ratios, however the NADPH coupling efficiency decreased when unsaturated aldehydes were included, or when the temperature of the reaction was reduced. CONCLUSIONS The unsaturated aldehyde, trans-2-decenal, stimulates BM3-F87G catalyzed oxidation of 4-fluorophenol through a cooperative active site binding mode that doesn't influence product distributions or coupling efficiencies, while 4-fluorophenol acts as a competitive inhibitor of aldehyde oxidation.
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Affiliation(s)
- Chelsea Ledford
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Monica McMahon
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Ashley Whitesell
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Ghalib Khan
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Suneel K Kandagatla
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Dow P Hurst
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Patricia H Reggio
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Gregory M Raner
- Department of Biology and Chemistry, Liberty University, Lynchburg, VA, USA.
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22
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Morales P, Gómez-Cañas M, Navarro G, Hurst DP, Carrillo-Salinas FJ, Lagartera L, Pazos R, Goya P, Reggio PH, Guaza C, Franco R, Fernández-Ruiz J, Jagerovic N. Chromenopyrazole, a Versatile Cannabinoid Scaffold with in Vivo Activity in a Model of Multiple Sclerosis. J Med Chem 2016; 59:6753-6771. [PMID: 27309150 DOI: 10.1021/acs.jmedchem.6b00397] [Citation(s) in RCA: 28] [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: 12/22/2022]
Abstract
A combination of molecular modeling and structure-activity relationship studies has been used to fine-tune CB2 selectivity in the chromenopyrazole ring, a versatile CB1/CB2 cannabinoid scaffold. Thus, a series of 36 new derivatives covering a wide range of structural diversity has been synthesized, and docking studies have been performed for some of them. Biological evaluation of the new compounds includes, among others, cannabinoid binding assays, functional studies, and surface plasmon resonance measurements. The most promising compound [43 (PM226)], a selective and potent CB2 agonist isoxazole derivative, was tested in the acute phase of Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD), a well-established animal model of primary progressive multiple sclerosis. Compound 43 dampened neuroinflammation by reducing microglial activation in the TMEV.
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Affiliation(s)
- Paula Morales
- Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Calle Juan de la Cierva, 3, E-28006 Madrid, Spain
| | - María Gómez-Cañas
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense de Madrid, E-28040 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), E-28040 Madrid, Spain
| | - Gemma Navarro
- Departamento de Bioquímica y Biología Molecular, Facultad de Biología, Universidad de Barcelona, E-08028 Barcelona, Spain
| | - Dow P Hurst
- Department of Chemistry and Biochemistry, University of North Carolina Greensboro, Greensboro, North Carolina 27402, United States
| | - Francisco J Carrillo-Salinas
- Grupo de Neuroinmunología Neurobiología Funcional y de Sistemas, Instituto Cajal, Consejo Superior de Investigaciones Científicas, E-28002 Madrid, Spain
| | - Laura Lagartera
- Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Calle Juan de la Cierva, 3, E-28006 Madrid, Spain
| | - Ruth Pazos
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense de Madrid, E-28040 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), E-28040 Madrid, Spain
| | - Pilar Goya
- Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Calle Juan de la Cierva, 3, E-28006 Madrid, Spain
| | - Patricia H Reggio
- Department of Chemistry and Biochemistry, University of North Carolina Greensboro, Greensboro, North Carolina 27402, United States
| | - Carmen Guaza
- Grupo de Neuroinmunología Neurobiología Funcional y de Sistemas, Instituto Cajal, Consejo Superior de Investigaciones Científicas, E-28002 Madrid, Spain
| | - Rafael Franco
- Departamento de Bioquímica y Biología Molecular, Facultad de Biología, Universidad de Barcelona, E-08028 Barcelona, Spain
| | - Javier Fernández-Ruiz
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense de Madrid, E-28040 Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), E-28040 Madrid, Spain
| | - Nadine Jagerovic
- Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Calle Juan de la Cierva, 3, E-28006 Madrid, Spain
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23
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Laprairie RB, Kulkarni AR, Kulkarni PM, Hurst DP, Lynch D, Reggio PH, Janero DR, Pertwee RG, Stevenson LA, Kelly MEM, Denovan-Wright EM, Thakur GA. Mapping Cannabinoid 1 Receptor Allosteric Site(s): Critical Molecular Determinant and Signaling Profile of GAT100, a Novel, Potent, and Irreversibly Binding Probe. ACS Chem Neurosci 2016; 7:776-98. [PMID: 27046127 DOI: 10.1021/acschemneuro.6b00041] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
One of the most abundant G-protein coupled receptors (GPCRs) in brain, the cannabinoid 1 receptor (CB1R), is a tractable therapeutic target for treating diverse psychobehavioral and somatic disorders. Adverse on-target effects associated with small-molecule CB1R orthosteric agonists and inverse agonists/antagonists have plagued their translational potential. Allosteric CB1R modulators offer a potentially safer modality through which CB1R signaling may be directed for therapeutic benefit. Rational design of candidate, druglike CB1R allosteric modulators requires greater understanding of the architecture of the CB1R allosteric endodomain(s) and the capacity of CB1R allosteric ligands to tune the receptor's information output. We have recently reported the synthesis of a focused library of rationally designed, covalent analogues of Org27569 and PSNCBAM-1, two prototypic CB1R negative allosteric modulators (NAMs). Among the novel, pharmacologically active CB1R NAMs reported, the isothiocyanate GAT100 emerged as the lead by virtue of its exceptional potency in the [(35)S]GTPγS and β-arrestin signaling assays and its ability to label CB1R as a covalent allosteric probe with significantly reduced inverse agonism in the [(35)S]GTPγS assay as compared to Org27569. We report here a comprehensive functional profiling of GAT100 across an array of important downstream cell-signaling pathways and analysis of its potential orthosteric probe-dependence and signaling bias. The results demonstrate that GAT100 is a NAM of the orthosteric CB1R agonist CP55,940 and the endocannabinoids 2-arachidonoylglycerol and anandamide for β-arrestin1 recruitment, PLCβ3 and ERK1/2 phosphorylation, cAMP accumulation, and CB1R internalization in HEK293A cells overexpressing CB1R and in Neuro2a and STHdh(Q7/Q7) cells endogenously expressing CB1R. Distinctively, GAT100 was a more potent and efficacious CB1R NAM than Org27569 and PSNCBAM-1 in all signaling assays and did not exhibit the inverse agonism associated with Org27569 and PSNCBAM-1. Computational docking studies implicate C7.38(382) as a key feature of GAT100 ligand-binding motif. These data help inform the engineering of newer-generation, druggable CB1R allosteric modulators and demonstrate the utility of GAT100 as a covalent probe for mapping structure-function correlates characteristic of the druggable CB1R allosteric space.
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Affiliation(s)
| | | | | | - Dow P. Hurst
- Center
for Drug Discovery, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Diane Lynch
- Center
for Drug Discovery, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Patricia H. Reggio
- Center
for Drug Discovery, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | | | - Roger G. Pertwee
- School of
Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill,
Aberdeen AB25 2ZD, Scotland
| | - Lesley A. Stevenson
- School of
Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill,
Aberdeen AB25 2ZD, Scotland
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24
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Glass M, Govindpani K, Furkert DP, Hurst DP, Reggio PH, Flanagan JU. One for the Price of Two…Are Bivalent Ligands Targeting Cannabinoid Receptor Dimers Capable of Simultaneously Binding to both Receptors? Trends Pharmacol Sci 2016; 37:353-363. [PMID: 26917061 DOI: 10.1016/j.tips.2016.01.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [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: 11/26/2015] [Revised: 01/27/2016] [Accepted: 01/29/2016] [Indexed: 10/22/2022]
Abstract
Bivalent ligands bridging two G-protein-coupled receptors (GPCRs) provide valuable pharmacological tools to target oligomers. The success of therapeutically targeting the cannabinoid CB1 receptor has been limited, in part due to its widespread neuronal distribution. Therefore, CB1 ligands targeting oligomers that exhibit restricted distribution or altered pharmacology are highly desirable, and several bivalent ligands containing a CB1 pharmacophore have been reported. Bivalent ligand action presumes that the ligand simultaneously binds to both receptors within the dimeric complex. However, based on the current understanding of CB1 ligand binding, existing bivalent ligands are too short to bind both receptors simultaneously. However, ligands with longer linkers may not be the solution, because evidence suggests that ligands enter CB1 through the lipid bilayer and, thus, linkers are unlikely to exit the receptor through its external face. Thus, the entire premise of designing bivalent ligands targeting CB1 must be revisited.
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Affiliation(s)
- Michelle Glass
- Department of Pharmacology, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
| | - Karan Govindpani
- Department of Pharmacology, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Daniel P Furkert
- School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Dow P Hurst
- Center for Drug Design, University of North Carolina Greensboro, Greensboro, NC 27402, USA
| | - Patricia H Reggio
- Center for Drug Design, University of North Carolina Greensboro, Greensboro, NC 27402, USA
| | - Jack U Flanagan
- Department of Pharmacology, School of Medical Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand; Auckland Cancer Society Research Centre and Maurice Wilkens Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland, New Zealand
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25
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Meza-Aviña ME, Lingerfelt MA, Console-Bram LM, Gamage TF, Sharir H, Gettys KE, Hurst DP, Kotsikorou E, Shore DM, Caron MG, Rao N, Barak LS, Abood ME, Reggio PH, Croatt MP. Design, synthesis, and analysis of antagonists of GPR55: Piperidine-substituted 1,3,4-oxadiazol-2-ones. Bioorg Med Chem Lett 2016; 26:1827-1830. [PMID: 26916440 DOI: 10.1016/j.bmcl.2016.02.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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: 11/04/2015] [Revised: 02/09/2016] [Accepted: 02/11/2016] [Indexed: 12/24/2022]
Abstract
A series of 1,3,4-oxadiazol-2-ones was synthesized and tested for activity as antagonists at GPR55 in cellular beta-arrestin redistribution assays. The synthesis was designed to be modular in nature so that a sufficient number of analogues could be rapidly accessed to explore initial structure-activity relationships. The design of analogues was guided by the docking of potential compounds into a model of the inactive form of GPR55. The results of the assays were used to learn more about the binding pocket of GPR55. With this oxadiazolone scaffold, it was determined that modification of the aryl group adjacent to the oxadiazolone ring was often detrimental and that the distal cyclopropane was beneficial for activity. These results will guide further exploration of this receptor.
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Affiliation(s)
- Maria Elena Meza-Aviña
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Mary A Lingerfelt
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Linda M Console-Bram
- Center for Substance Abuse Research, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Thomas F Gamage
- Center for Substance Abuse Research, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Haleli Sharir
- Center for Substance Abuse Research, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Kristen E Gettys
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Dow P Hurst
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Evangelia Kotsikorou
- Department of Chemistry, University of Texas - Pan American, Edinburg, Texas 78539, United States
| | - Derek M Shore
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Marc G Caron
- Duke University Medical Center, Durham, North Carolina 27709, United States
| | - Narasinga Rao
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Larry S Barak
- Duke University Medical Center, Durham, North Carolina 27709, United States
| | - Mary E Abood
- Center for Substance Abuse Research, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Patricia H Reggio
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Mitchell P Croatt
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
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26
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Fakhouri L, El-Elimat T, Hurst DP, Reggio PH, Pearce CJ, Oberlies NH, Croatt MP. Isolation, semisynthesis, covalent docking and transforming growth factor beta-activated kinase 1 (TAK1)-inhibitory activities of (5Z)-7-oxozeaenol analogues. Bioorg Med Chem 2015; 23:6993-9. [PMID: 26481152 DOI: 10.1016/j.bmc.2015.09.037] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [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: 07/12/2015] [Revised: 09/14/2015] [Accepted: 09/22/2015] [Indexed: 12/22/2022]
Abstract
(5Z)-7-Oxozeanol and related analogues were isolated and screened to explore their activity as TAK1 inhibitors. Seven analogues were synthesized and more than a score of natural products isolated that examined the role that different areas of the molecule contribute to TAK1 inhibition. A novel nonaromatic difluoro-derivative was synthesized that had similar potency compared to the lead. This is the first example of a nonaromatic compound in this class to have TAK1 inhibition. Covalent docking for the isolated and synthesized analogues was carried out and found a strong correlation between the observed activities and the calculated binding.
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Affiliation(s)
- Lara Fakhouri
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Tamam El-Elimat
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Dow P Hurst
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Patricia H Reggio
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Cedric J Pearce
- Mycosynthetix, Inc., 505 Meadowlands Drive, Suite 103, Hillsborough, USA
| | - Nicholas H Oberlies
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Mitchell P Croatt
- Department of Chemistry and Biochemistry, Natural Products and Drug Discovery Center, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
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27
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Ragusa G, Gómez-Cañas M, Morales P, Hurst DP, Deligia F, Pazos R, Pinna GA, Fernández-Ruiz J, Goya P, Reggio PH, Jagerovic N, García-Arencibia M, Murineddu G. Synthesis, pharmacological evaluation and docking studies of pyrrole structure-based CB2 receptor antagonists. Eur J Med Chem 2015. [PMID: 26209834 DOI: 10.1016/j.ejmech.2015.06.057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [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] [Indexed: 11/17/2022]
Abstract
During the last years, there has been a continuous interest in the development of cannabinoid receptor ligands that may serve as therapeutic agents and/or as experimental tools. This prompted us to design and synthesize analogues of the CB2 receptor antagonist N-fenchyl-5-(4-chloro-3-methyl-phenyl)-1-(4-methyl-benzyl)-1H-pyrazole-3-carboxamide (SR144528). The structural modifications involved the bioisosteric replacement of the pyrazole ring by a pyrrole ring and variations on the amine carbamoyl substituents. Two of these compounds, the fenchyl pyrrole analogue 6 and the myrtanyl derivative 10, showed high affinity (Ki in the low nM range) and selectivity for the CB2 receptor and both resulted to be antagonists/inverse agonists in [(35)S]-GTPγS binding analysis and in an in vitro CB2 receptor bioassay. Cannabinoid receptor binding data of the series allowed identifying steric constraints within the CB2 binding pocket using a study of Van der Waals' volume maps. Glide docking studies revealed that all docked compounds bind in the same region of the CB2 receptor inactive state model.
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Affiliation(s)
- Giulio Ragusa
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via F. Muroni 23/A, 07100 Sassari, Italy
| | - María Gómez-Cañas
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Investigación en Neuroquímica, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain; Campus de Excelencia Internacional (CEI-Moncloa), Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Paula Morales
- Instituto de Química Médica, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
| | - Dow P Hurst
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Francesco Deligia
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via F. Muroni 23/A, 07100 Sassari, Italy
| | - Ruth Pazos
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Investigación en Neuroquímica, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain; Campus de Excelencia Internacional (CEI-Moncloa), Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Gerard A Pinna
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via F. Muroni 23/A, 07100 Sassari, Italy
| | - Javier Fernández-Ruiz
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Investigación en Neuroquímica, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain; Campus de Excelencia Internacional (CEI-Moncloa), Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Pilar Goya
- Instituto de Química Médica, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
| | - Patricia H Reggio
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, USA
| | - Nadine Jagerovic
- Instituto de Química Médica, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain.
| | - Moisés García-Arencibia
- Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Investigación en Neuroquímica, Facultad de Medicina, Universidad Complutense, 28040 Madrid, Spain; Campus de Excelencia Internacional (CEI-Moncloa), Madrid, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain.
| | - Gabriele Murineddu
- Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via F. Muroni 23/A, 07100 Sassari, Italy.
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28
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Kimura T, Vukoti K, Lynch DL, Hurst DP, Grossfield A, Pitman MC, Reggio PH, Yeliseev AA, Gawrisch K. Global Fold of Human Cannabinoid Type 2 Receptor Probed by Solid-State NMR and Molecular Dynamics Simulations. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.1390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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29
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Mahmoud MM, Olszewska T, Liu H, Shore DM, Hurst DP, Reggio PH, Lu D, Kendall DA. (4-(Bis(4-fluorophenyl)methyl)piperazin-1-yl)(cyclohexyl)methanone hydrochloride (LDK1229): a new cannabinoid CB1 receptor inverse agonist from the class of benzhydryl piperazine analogs. Mol Pharmacol 2014; 87:197-206. [PMID: 25411367 DOI: 10.1124/mol.114.095471] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Some inverse agonists of cannabinoid receptor type 1 (CB1) have been demonstrated to be anorectic antiobesity drug candidates. However, the first generation of CB1 inverse agonists, represented by rimonabant (SR141716A), otenabant, and taranabant, are centrally active, with a high level of psychiatric side effects. Hence, the discovery of CB1 inverse agonists with a chemical scaffold distinct from these holds promise for developing peripherally active CB1 inverse agonists with fewer side effects. We generated a new CB1 inverse agonist, (4-(bis(4-fluorophenyl)methyl)piperazin-1-yl)(cyclohexyl)methanone hydrochloride (LDK1229), from the class of benzhydryl piperazine analogs. This compound binds to CB1 more selectively than cannabinoid receptor type 2, with a Ki value of 220 nM. Comparable CB1 binding was also observed by analogs 1-[bis(4-fluorophenyl)methyl]-4-cinnamylpiperazine dihydrochloride (LDK1203) and 1-[bis(4-fluorophenyl)methyl]-4-tosylpiperazine hydrochloride (LDK1222), which differed by the substitution on the piperazine ring where the piperazine of LDK1203 and LDK1222 are substituted by an alkyl group and a tosyl group, respectively. LDK1229 exhibits efficacy comparable with SR141716A in antagonizing the basal G protein coupling activity of CB1, as indicated by a reduction in guanosine 5'-O-(3-thio)triphosphate binding. Consistent with inverse agonist behavior, increased cell surface localization of CB1 upon treatment with LDK1229 was also observed. Although docking and mutational analysis showed that LDK1229 forms similar interactions with the receptor as SR141716A does, the benzhydryl piperazine scaffold is structurally distinct from the first-generation CB1 inverse agonists. It offers new opportunities for developing novel CB1 inverse agonists through the optimization of molecular properties, such as the polar surface area and hydrophilicity, to reduce the central activity observed with SR141716A.
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Affiliation(s)
- Mariam M Mahmoud
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut (M.M.M.); Irma Lerma Rangel College of Pharmacy, Texas A&M Health Science Center, Kingsville, Texas (T.O., H. L., D.L.); Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina (D.M.S., D.P.H., P.H.R.); and Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut (D.A.K.)
| | - Teresa Olszewska
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut (M.M.M.); Irma Lerma Rangel College of Pharmacy, Texas A&M Health Science Center, Kingsville, Texas (T.O., H. L., D.L.); Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina (D.M.S., D.P.H., P.H.R.); and Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut (D.A.K.)
| | - Hui Liu
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut (M.M.M.); Irma Lerma Rangel College of Pharmacy, Texas A&M Health Science Center, Kingsville, Texas (T.O., H. L., D.L.); Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina (D.M.S., D.P.H., P.H.R.); and Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut (D.A.K.)
| | - Derek M Shore
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut (M.M.M.); Irma Lerma Rangel College of Pharmacy, Texas A&M Health Science Center, Kingsville, Texas (T.O., H. L., D.L.); Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina (D.M.S., D.P.H., P.H.R.); and Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut (D.A.K.)
| | - Dow P Hurst
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut (M.M.M.); Irma Lerma Rangel College of Pharmacy, Texas A&M Health Science Center, Kingsville, Texas (T.O., H. L., D.L.); Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina (D.M.S., D.P.H., P.H.R.); and Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut (D.A.K.)
| | - Patricia H Reggio
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut (M.M.M.); Irma Lerma Rangel College of Pharmacy, Texas A&M Health Science Center, Kingsville, Texas (T.O., H. L., D.L.); Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina (D.M.S., D.P.H., P.H.R.); and Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut (D.A.K.)
| | - Dai Lu
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut (M.M.M.); Irma Lerma Rangel College of Pharmacy, Texas A&M Health Science Center, Kingsville, Texas (T.O., H. L., D.L.); Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina (D.M.S., D.P.H., P.H.R.); and Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut (D.A.K.)
| | - Debra A Kendall
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut (M.M.M.); Irma Lerma Rangel College of Pharmacy, Texas A&M Health Science Center, Kingsville, Texas (T.O., H. L., D.L.); Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, North Carolina (D.M.S., D.P.H., P.H.R.); and Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut (D.A.K.)
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30
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Lucchesi V, Hurst DP, Shore DM, Bertini S, Ehrmann BM, Allarà M, Lawrence L, Ligresti A, Minutolo F, Saccomanni G, Sharir H, Macchia M, Di Marzo V, Abood ME, Reggio PH, Manera C. CB2-selective cannabinoid receptor ligands: synthesis, pharmacological evaluation, and molecular modeling investigation of 1,8-Naphthyridin-2(1H)-one-3-carboxamides. J Med Chem 2014; 57:8777-91. [PMID: 25272206 PMCID: PMC4234427 DOI: 10.1021/jm500807e] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [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: 02/03/2023]
Abstract
![]()
We
have recently identified 1,8-naphthyridin-2(1H)-one-3-carboxamide
as a new scaffold very suitable for the development
of new CB2 receptor potent and selective ligands. In this paper we
describe a number of additional derivatives in which the same central
scaffold has been variously functionalized in position 1 or 6. All
new compounds showed high selectivity and affinity in the nanomolar
range for the CB2 receptor. Furthermore, we found that their functional
activity is controlled by the presence of the substituents at position
C-6 of the naphthyridine scaffold. In fact, the introduction of substituents
in this position determined a functionality switch from agonist to
antagonists/inverse agonists. Finally, docking studies showed that
the difference between the pharmacology of these ligands may be in
the ability/inability to block the Toggle Switch W6.48(258) (χ1 g+ → trans) transition.
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Affiliation(s)
- Valentina Lucchesi
- Dipartimento di Farmacia, Università di Pisa , Via Bonanno 6, 56126 Pisa, Italy
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31
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Mnpotra JS, Qiao Z, Cai J, Lynch DL, Grossfield A, Leioatts N, Hurst DP, Pitman MC, Song ZH, Reggio PH. Structural basis of G protein-coupled receptor-Gi protein interaction: formation of the cannabinoid CB2 receptor-Gi protein complex. J Biol Chem 2014; 289:20259-72. [PMID: 24855641 DOI: 10.1074/jbc.m113.539916] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In this study, we applied a comprehensive G protein-coupled receptor-Gαi protein chemical cross-linking strategy to map the cannabinoid receptor subtype 2 (CB2)-Gαi interface and then used molecular dynamics simulations to explore the dynamics of complex formation. Three cross-link sites were identified using LC-MS/MS and electrospray ionization-MS/MS as follows: 1) a sulfhydryl cross-link between C3.53(134) in TMH3 and the Gαi C-terminal i-3 residue Cys-351; 2) a lysine cross-link between K6.35(245) in TMH6 and the Gαi C-terminal i-5 residue, Lys-349; and 3) a lysine cross-link between K5.64(215) in TMH5 and the Gαi α4β6 loop residue, Lys-317. To investigate the dynamics and nature of the conformational changes involved in CB2·Gi complex formation, we carried out microsecond-time scale molecular dynamics simulations of the CB2 R*·Gαi1β1γ2 complex embedded in a 1-palmitoyl-2-oleoyl-phosphatidylcholine bilayer, using cross-linking information as validation. Our results show that although molecular dynamics simulations started with the G protein orientation in the β2-AR*·Gαsβ1γ2 complex crystal structure, the Gαi1β1γ2 protein reoriented itself within 300 ns. Two major changes occurred as follows. 1) The Gαi1 α5 helix tilt changed due to the outward movement of TMH5 in CB2 R*. 2) A 25° clockwise rotation of Gαi1β1γ2 underneath CB2 R* occurred, with rotation ceasing when Pro-139 (IC-2 loop) anchors in a hydrophobic pocket on Gαi1 (Val-34, Leu-194, Phe-196, Phe-336, Thr-340, Ile-343, and Ile-344). In this complex, all three experimentally identified cross-links can occur. These findings should be relevant for other class A G protein-coupled receptors that couple to Gi proteins.
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Affiliation(s)
- Jagjeet S Mnpotra
- From the Department of Chemistry and Biochemistry, University of North Carolina, Greensboro, North Carolina 27402
| | - Zhuanhong Qiao
- the Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky 40292
| | - Jian Cai
- the Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky 40292
| | - Diane L Lynch
- From the Department of Chemistry and Biochemistry, University of North Carolina, Greensboro, North Carolina 27402
| | - Alan Grossfield
- the Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642, and
| | - Nicholas Leioatts
- the Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642, and
| | - Dow P Hurst
- From the Department of Chemistry and Biochemistry, University of North Carolina, Greensboro, North Carolina 27402
| | - Michael C Pitman
- From the Department of Chemistry and Biochemistry, University of North Carolina, Greensboro, North Carolina 27402, the Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598
| | - Zhao-Hui Song
- the Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky 40292,
| | - Patricia H Reggio
- From the Department of Chemistry and Biochemistry, University of North Carolina, Greensboro, North Carolina 27402,
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Vallée M, Vitiello S, Bellocchio L, Hébert-Chatelain E, Monlezun S, Martin-Garcia E, Kasanetz F, Baillie GL, Panin F, Cathala A, Roullot-Lacarrière V, Fabre S, Hurst DP, Lynch DL, Shore DM, Deroche-Gamonet V, Spampinato U, Revest JM, Maldonado R, Reggio PH, Ross RA, Marsicano G, Piazza PV. Pregnenolone can protect the brain from cannabis intoxication. Science 2014; 343:94-8. [PMID: 24385629 DOI: 10.1126/science.1243985] [Citation(s) in RCA: 207] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Pregnenolone is considered the inactive precursor of all steroid hormones, and its potential functional effects have been largely uninvestigated. The administration of the main active principle of Cannabis sativa (marijuana), Δ(9)-tetrahydrocannabinol (THC), substantially increases the synthesis of pregnenolone in the brain via activation of the type-1 cannabinoid (CB1) receptor. Pregnenolone then, acting as a signaling-specific inhibitor of the CB1 receptor, reduces several effects of THC. This negative feedback mediated by pregnenolone reveals a previously unknown paracrine/autocrine loop protecting the brain from CB1 receptor overactivation that could open an unforeseen approach for the treatment of cannabis intoxication and addiction.
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Affiliation(s)
- Monique Vallée
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U862, F-33000 Bordeaux, France
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Shore DM, Hurst DP, Reggio PH. Identification of an Endogenous Allosteric Modulator's Binding Site at the Human Cannabinoid-1 Receptor, using the Forced-Biased Metropolis Monte Carlo Simulated Annealing Method (Mmc). Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.1779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Zhao P, Lane TR, Gao HGL, Hurst DP, Kotsikorou E, Le L, Brailoiu E, Reggio PH, Abood ME. Crucial positively charged residues for ligand activation of the GPR35 receptor. J Biol Chem 2013; 289:3625-38. [PMID: 24347166 DOI: 10.1074/jbc.m113.508382] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [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: 12/19/2022] Open
Abstract
GPR35 is a G protein-coupled receptor expressed in the immune, gastrointestinal, and nervous systems in gastric carcinomas and is implicated in heart failure and pain perception. We investigated residues in GPR35 responsible for ligand activation and the receptor structure in the active state. GPR35 contains numerous positively charged amino acids that face into the binding pocket that cluster in two distinct receptor regions, TMH3-4-5-6 and TMH1-2-7. Computer modeling implicated TMH3-4-5-6 for activation by the GPR35 agonists zaprinast and pamoic acid. Mutation results for the TMH1-2-7 region of GPR35 showed no change in ligand efficacies at the K1.32A, R2.65A, R7.33A, and K7.40A mutants. However, mutation of arginine residues in the TMH3-4-5-6 region (R4.60, R6.58, R3.36, R(164), and R(167) in the EC2 loop) had effects on signaling for one or both agonists tested. R4.60A resulted in a total ablation of agonist-induced activation in both the β-arrestin trafficking and ERK1/2 activation assays. R6.58A increased the potency of zaprinast 30-fold in the pERK assay. The R(167)A mutant decreased the potency of pamoic acid in the β-arrestin trafficking assay. The R(164)A and R(164)L mutants decreased potencies of both agonists. Similar trends for R6.58A and R(167)A were observed in calcium responses. Computer modeling showed that the R6.58A mutant has additional interactions with zaprinast. R3.36A did not express on the cell surface but was trapped in the cytoplasm. The lack of surface expression of R3.36A was rescued by a GPR35 antagonist, CID2745687. These results clearly show that R4.60, R(164), R(167), and R6.58 play crucial roles in the agonist initiated activation of GPR35.
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Kotsikorou E, Sharir H, Shore DM, Hurst DP, Lynch DL, Madrigal KE, Heynen-Genel S, Milan LB, Chung TDY, Seltzman HH, Bai Y, Caron MG, Barak LS, Croatt MP, Abood ME, Reggio PH. Identification of the GPR55 antagonist binding site using a novel set of high-potency GPR55 selective ligands. Biochemistry 2013; 52:9456-69. [PMID: 24274581 DOI: 10.1021/bi4008885] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
GPR55 is a class A G protein-coupled receptor (GPCR) that has been implicated in inflammatory pain, neuropathic pain, metabolic disorder, bone development, and cancer. Initially deorphanized as a cannabinoid receptor, GPR55 has been shown to be activated by non-cannabinoid ligands such as l-α-lysophosphatidylinositol (LPI). While there is a growing body of evidence of physiological and pathophysiological roles for GPR55, the paucity of specific antagonists has limited its study. In collaboration with the Molecular Libraries Probe Production Centers Network initiative, we identified a series of GPR55 antagonists using a β-arrestin, high-throughput, high-content screen of ~300000 compounds. This screen yielded novel, GPR55 antagonist chemotypes with IC50 values in the range of 0.16-2.72 μM [Heynen-Genel, S., et al. (2010) Screening for Selective Ligands for GPR55: Antagonists (ML191, ML192, ML193) (Bookshelf ID NBK66153; PMID entry 22091481)]. Importantly, many of the GPR55 antagonists were completely selective, with no agonism or antagonism against GPR35, CB1, or CB2 up to 20 μM. Using a model of the GPR55 inactive state, we studied the binding of an antagonist series that emerged from this screen. These studies suggest that GPR55 antagonists possess a head region that occupies a horizontal binding pocket extending into the extracellular loop region, a central ligand portion that fits vertically in the receptor binding pocket and terminates with a pendant aromatic or heterocyclic ring that juts out. Both the region that extends extracellularly and the pendant ring are features associated with antagonism. Taken together, our results provide a set of design rules for the development of second-generation GPR55 selective antagonists.
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Affiliation(s)
- Evangelia Kotsikorou
- Department of Chemistry, University of Texas-Pan American , Edinburg, Texas 78539, United States
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Kimura T, Vukoti K, Lynch DL, Hurst DP, Grossfield A, Pitman MC, Reggio PH, Yeliseev AA, Gawrisch K. Global fold of human cannabinoid type 2 receptor probed by solid-state 13C-, 15N-MAS NMR and molecular dynamics simulations. Proteins 2013; 82:452-65. [PMID: 23999926 DOI: 10.1002/prot.24411] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 08/12/2013] [Accepted: 08/21/2013] [Indexed: 12/12/2022]
Abstract
The global fold of human cannabinoid type 2 (CB2 ) receptor in the agonist-bound active state in lipid bilayers was investigated by solid-state (13)C- and (15)N magic-angle spinning (MAS) NMR, in combination with chemical-shift prediction from a structural model of the receptor obtained by microsecond-long molecular dynamics (MD) simulations. Uniformly (13)C- and (15)N-labeled CB2 receptor was expressed in milligram quantities by bacterial fermentation, purified, and functionally reconstituted into liposomes. (13)C MAS NMR spectra were recorded without sensitivity enhancement for direct comparison of Cα, Cβ, and C=O bands of superimposed resonances with predictions from protein structures generated by MD. The experimental NMR spectra matched the calculated spectra reasonably well indicating agreement of the global fold of the protein between experiment and simulations. In particular, the (13) C chemical shift distribution of Cα resonances was shown to be very sensitive to both the primary amino acid sequence and the secondary structure of CB2. Thus the shape of the Cα band can be used as an indicator of CB2 global fold. The prediction from MD simulations indicated that upon receptor activation a rather limited number of amino acid residues, mainly located in the extracellular Loop 2 and the second half of intracellular Loop 3, change their chemical shifts significantly (≥ 1.5 ppm for carbons and ≥ 5.0 ppm for nitrogens). Simulated two-dimensional (13) Cα(i)-(13)C=O(i) and (13)C=O(i)-(15)NH(i + 1) dipolar-interaction correlation spectra provide guidance for selective amino acid labeling and signal assignment schemes to study the molecular mechanism of activation of CB2 by solid-state MAS NMR.
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Affiliation(s)
- Tomohiro Kimura
- Laboratory of Membrane Biochemistry and Biophysics, NIAAA, NIH, Bethesda, Maryland, 20892
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37
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Kotsikorou E, Navas F, Roche MJ, Gilliam AF, Thomas B, Seltzman HH, Kumar P, Song ZH, Hurst DP, Lynch DL, Reggio PH. The importance of hydrogen bonding and aromatic stacking to the affinity and efficacy of cannabinoid receptor CB2 antagonist, 5-(4-chloro-3-methylphenyl)-1-[(4-methylphenyl)methyl]-N-[(1S,2S,4R)-1,3,3-trimethylbicyclo[2.2.1]hept-2-yl]-1H-pyrazole-3-carboxamide (SR144528). J Med Chem 2013; 56:6593-612. [PMID: 23855811 PMCID: PMC3804063 DOI: 10.1021/jm400070u] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [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: 12/11/2022]
Abstract
Despite the therapeutic promise of the subnanomolar affinity cannabinoid CB2 antagonist, 5-(4-chloro-3-methylphenyl)-1-[(4-methylphenyl)methyl]-N-[(1S,2S,4R)-1,3,3-trimethylbicyclo[2.2.1]hept-2-yl]-1H-pyrazole-3-carboxamide (SR144528, 1), little is known about its binding site interactions and no primary interaction site for 1 at CB2 has been identified. We report here the results of Glide docking studies in our cannabinoid CB2 inactive state model that were then tested via compound synthesis, binding, and functional assays. Our results show that the amide functional group of 1 is critical to its CB2 affinity and efficacy and that aromatic stacking interactions in the TMH5/6 aromatic cluster of CB2 are also important. Molecular modifications that increased the positive electrostatic potential in the region between the fenchyl and aromatic rings led to more efficacious compounds. This result is consistent with the EC-3 loop negatively charged amino acid, D275 (identified via Glide docking studies) acting as the primary interaction site for 1 and its analogues.
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Affiliation(s)
| | - Frank Navas
- Research Triangle Institute, Research Triangle Park, NC 27609
| | | | - Anne F. Gilliam
- Research Triangle Institute, Research Triangle Park, NC 27609
| | - Brian Thomas
- Research Triangle Institute, Research Triangle Park, NC 27609
| | | | - Pritesh Kumar
- Department of Pharmacology and Toxicology, University of Louisville, University of Louisville School of Medicine, Louisville, KY 40292
| | - Zhao-Hui Song
- Department of Pharmacology and Toxicology, University of Louisville, University of Louisville School of Medicine, Louisville, KY 40292
| | - Dow P. Hurst
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402
| | - Diane L. Lynch
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402
| | - Patricia H. Reggio
- Center for Drug Discovery, Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402
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Hurst DP, Schmeisser M, Reggio PH. Endogenous lipid activated G protein-coupled receptors: emerging structural features from crystallography and molecular dynamics simulations. Chem Phys Lipids 2013; 169:46-56. [PMID: 23485612 DOI: 10.1016/j.chemphyslip.2013.01.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [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] [Received: 09/05/2012] [Revised: 01/20/2013] [Accepted: 01/22/2013] [Indexed: 01/01/2023]
Abstract
Class A G-protein coupled receptors (GPCRs) are thought to have a common topology that includes seven transmembrane alpha helices (TMHs) that are arranged to form a closed bundle. This bundle forms the ligand binding pocket into which ligands are commonly thought to enter via the extracellular milieu. This ligand approach direction makes sense for GPCRs that have small positively charged ligands, such as the beta-2-adrenergic or the dopamine D2 receptor. However, there is a growing sub-group of Class A GPCRs that bind lipid-derived endogenous ligands, such as the cannabinoid CB1 and CB2 receptors (with endogenous ligands, N-arachidonoylethanolamine (anandamide) and sn-2-arachidonylglycerol (2-AG)) and the S1P1-5 receptors (with endogenous ligand, sphingosine-1-phosphate). Even the widely studied Class A GPCR, rhodopsin, binds a highly lipophillic chromophore (11-cis-retinal). For these receptors, ligand approach from the extracellular milieu has seemed unlikely given that the ligands of these receptors readily partition into lipid or are actually synthesized in the lipid bilayer. The recent X-ray-crystal structure of the sub-type 1 sphingosine-1-phosphate receptor (S1P1) provides important information on the key structural variations that may be the hallmarks for a Class A GPCR that binds lipid-derived ligands. These include an extracellular domain that is closed off to the extracellular milieu and the existence of an opening between transmembrane helices that may serve as a portal for ligand entry via the lipid bilayer. This review examines structural aspects that the cannabinoid receptors may share with the S1P1 receptor based upon sequence homology. This review also examines experimental and simulation results that suggest ligand entry via a lipid portal is quite likely for this emerging sub-group.
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Affiliation(s)
- Dow P Hurst
- Department of Chemistry and Biochemistry, University of North Carolina Greensboro, Greensboro, NC 27402, USA
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Zheng H, Pearsall EA, Hurst DP, Zhang Y, Chu J, Zhou Y, Reggio PH, Loh HH, Law PY. Palmitoylation and membrane cholesterol stabilize μ-opioid receptor homodimerization and G protein coupling. BMC Cell Biol 2012; 13:6. [PMID: 22429589 PMCID: PMC3317874 DOI: 10.1186/1471-2121-13-6] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [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] [Received: 09/19/2011] [Accepted: 03/19/2012] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND A cholesterol-palmitoyl interaction has been reported to occur in the dimeric interface of the β₂-adrenergic receptor crystal structure. We sought to investigate whether a similar phenomenon could be observed with μ-opioid receptor (OPRM1), and if so, to assess the role of cholesterol in this class of G protein-coupled receptor (GPCR) signaling. RESULTS C3.55(170) was determined to be the palmitoylation site of OPRM1. Mutation of this Cys to Ala did not affect the binding of agonists, but attenuated receptor signaling and decreased cholesterol associated with the receptor signaling complex. In addition, both attenuation of receptor palmitoylation (by mutation of C3.55[170] to Ala) and inhibition of cholesterol synthesis (by treating the cells with simvastatin, a HMG-CoA reductase inhibitor) impaired receptor signaling, possibly by decreasing receptor homodimerization and Gαi2 coupling; this was demonstrated by co-immunoprecipitation, immunofluorescence colocalization and fluorescence resonance energy transfer (FRET) analyses. A computational model of the OPRM1 homodimer structure indicated that a specific cholesterol-palmitoyl interaction can facilitate OPRM1 homodimerization at the TMH4-TMH4 interface. CONCLUSIONS We demonstrate that C3.55(170) is the palmitoylation site of OPRM1 and identify a cholesterol-palmitoyl interaction in the OPRM1 complex. Our findings suggest that this interaction contributes to OPRM1 signaling by facilitating receptor homodimerization and G protein coupling. This conclusion is supported by computational modeling of the OPRM1 homodimer.
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Affiliation(s)
- Hui Zheng
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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Cumella J, Hernández-Folgado L, Girón R, Sánchez E, Morales P, Hurst DP, Gómez-Cañas M, Gómez-Ruiz M, Pinto DCGA, Goya P, Reggio PH, Martin MI, Fernández-Ruiz J, Silva AMS, Jagerovic N. Inside Back Cover: Chromenopyrazoles: Non-psychoactive and Selective CB 1Cannabinoid Agonists with Peripheral Antinociceptive Properties (ChemMedChem 3/2012). ChemMedChem 2012. [DOI: 10.1002/cmdc.201290011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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41
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Cumella J, Hernández-Folgado L, Girón R, Sánchez E, Morales P, Hurst DP, Gómez-Cañas M, Gómez-Ruiz M, Pinto DCGA, Goya P, Reggio PH, Martin MI, Fernández-Ruiz J, Silva AMS, Jagerovic N. Chromenopyrazoles: non-psychoactive and selective CB₁ cannabinoid agonists with peripheral antinociceptive properties. ChemMedChem 2012; 7:452-63. [PMID: 22302767 DOI: 10.1002/cmdc.201100568] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 01/18/2012] [Indexed: 01/01/2023]
Abstract
The unwanted psychoactive effects of cannabinoid receptor agonists have limited their development as medicines. These CB₁-mediated side effects are due to the fact that CB₁ receptors are largely expressed in the central nervous system (CNS). As it is known that CB₁ receptors are also located peripherally, there is growing interest in targeting cannabinoid receptors located outside the brain. A library of chromenopyrazoles designed analogously to the classical cannabinoid cannabinol were synthesized, characterized, and tested for cannabinoid activity. Radioligand binding assays were used to determine their affinities at CB₁ and CB₂ receptors. Structural features required for CB₁/CB₂ affinity and selectivity were explored by molecular modeling. Some compounds in the chromenopyrazole series were observed to be selective CB₁ ligands. These modeling studies suggest that full CB₁ selectivity over CB₂ can be explained by the presence of a pyrazole ring in the structure. The functional activities of selected chromenopyrazoles were evaluated in isolated tissues. In vivo behavioral tests were then carried out on the most effective CB₁ cannabinoid agonist, 13 a. Chromenopyrazole 13 a did not induce modifications in any of the tested parameters on the mouse cannabinoid tetrad, thus discounting CNS-mediated effects. This lack of agonistic activity in the CNS suggests that this compound does not readily cross the blood-brain barrier. Moreover, 13 a can induce antinociception in a rat peripheral model of orofacial pain. Taking into account the negative results obtained with the hot-plate test, the antinociception induced by 13 a in the orofacial test could be mediated through peripheral mechanisms.
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Affiliation(s)
- Jose Cumella
- Instituto de Química Médica, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
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Kotsikorou E, Madrigal KE, Hurst DP, Sharir H, Lynch DL, Heynen-Genel S, Milan LB, Chung TD, Seltzman HH, Bai Y, Caron MG, Barak L, Abood ME, Reggio PH. Identification of the GPR55 agonist binding site using a novel set of high-potency GPR55 selective ligands. Biochemistry 2011; 50:5633-47. [PMID: 21534610 PMCID: PMC3723401 DOI: 10.1021/bi200010k] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [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: 12/28/2022]
Abstract
Marijuana is the most widely abused illegal drug, and its spectrum of effects suggests that several receptors are responsible for the activity. Two cannabinoid receptor subtypes, CB1 and CB2, have been identified, but the complex pharmacological properties of exogenous cannabinoids and endocannabinoids are not fully explained by their signaling. The orphan receptor GPR55 binds a subset of CB1 and CB2 ligands and has been proposed as a cannabinoid receptor. This designation, however, is controversial as a result of recent studies in which lysophosphatidylinositol (LPI) was identified as a GPR55 agonist. Defining a biological role for GPR55 requires GPR55 selective ligands that have been unavailable. From a β-arrestin, high-throughput, high-content screen of 300000 compounds run in collaboration with the Molecular Libraries Probe Production Centers Network initiative (PubChem AID1965), we identified potent GPR55 selective agonists. By modeling of the GPR55 activated state, we compared the GPR55 binding conformations of three of the novel agonists obtained from the screen, CID1792197, CID1172084, and CID2440433 (PubChem Compound IDs), with that of LPI. Our modeling indicates the molecular shapes and electrostatic potential distributions of these agonists mimic those of LPI; the GPR55 binding site accommodates ligands that have inverted-L or T shapes with long, thin profiles that can fit vertically deep in the receptor binding pocket while their broad head regions occupy a horizontal binding pocket near the GPR55 extracellular loops. Our results will allow the optimization and design of second-generation GPR55 ligands and provide a means for distinguishing GPR55 selective ligands from those interacting with cannabinoid receptors.
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Affiliation(s)
| | - Karla E. Madrigal
- Center for Drug Discovery, UNCG Greensboro, Greensboro, NC 27402 USA
| | - Dow P. Hurst
- Center for Drug Discovery, UNCG Greensboro, Greensboro, NC 27402 USA
| | - Haleli Sharir
- Department of Anatomy and Cell Biology and Center for Substance Abuse Research, Temple University, Philadelphia, PA 19140 USA
| | - Diane L. Lynch
- Center for Drug Discovery, UNCG Greensboro, Greensboro, NC 27402 USA
| | - Susanne Heynen-Genel
- Conrad Prebys Center for Chemical Genomics at Sanford-Burnham Medical Research Institute, La Jolla, CA 92037 USA
| | - Loribelle B. Milan
- Conrad Prebys Center for Chemical Genomics at Sanford-Burnham Medical Research Institute, La Jolla, CA 92037 USA
| | - Thomas D.Y. Chung
- Conrad Prebys Center for Chemical Genomics at Sanford-Burnham Medical Research Institute, La Jolla, CA 92037 USA
| | - Herbert H. Seltzman
- Center for Organic and Medicinal Chemistry, Research Triangle Institute, Research Triangle Park, NC 27709 USA
| | - Yushi Bai
- Department of Cell Biology, Duke University, Durham, NC 27708 USA
| | - Marc G. Caron
- Department of Cell Biology, Duke University, Durham, NC 27708 USA
| | - Larry Barak
- Department of Cell Biology, Duke University, Durham, NC 27708 USA
| | - Mary E. Abood
- Department of Anatomy and Cell Biology and Center for Substance Abuse Research, Temple University, Philadelphia, PA 19140 USA
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Lynch DL, Poole EB, Hurst DP, Law PY, Pitman MC, Reggio PH. A specific Role for Cholesterol at the Mu Opioid Homodimer Interface. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.2090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Huffman JW, Hepburn SA, Reggio PH, Hurst DP, Wiley JL, Martin BR. Synthesis and pharmacology of 1-methoxy analogs of CP-47,497. Bioorg Med Chem 2010; 18:5475-82. [PMID: 20621488 PMCID: PMC2920039 DOI: 10.1016/j.bmc.2010.06.054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [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: 04/14/2010] [Revised: 06/15/2010] [Accepted: 06/17/2010] [Indexed: 11/29/2022]
Abstract
Three 1-methoxy analogs of CP-47,497 (7, 8, and 19) have been synthesized and their affinities for the cannabinoid CB(1) and CB(2) receptors have been determined. Although these compounds exhibit selectivity for the CB(2) receptor none have significant affinity for either receptor. Modeling and receptor docking studies were carried out, which provide a rationalization for the weak affinities of these compounds for either receptor.
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Affiliation(s)
- John W Huffman
- Howard L Hunter Laboratory, Clemson University, Clemson, SC 29634-0973, United States.
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Hurst DP, Grossfield A, Lynch DL, Feller S, Romo TD, Gawrisch K, Pitman MC, Reggio PH. A lipid pathway for ligand binding is necessary for a cannabinoid G protein-coupled receptor. J Biol Chem 2010; 285:17954-64. [PMID: 20220143 PMCID: PMC2878557 DOI: 10.1074/jbc.m109.041590] [Citation(s) in RCA: 176] [Impact Index Per Article: 12.6] [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: 07/06/2009] [Revised: 02/13/2010] [Indexed: 11/06/2022] Open
Abstract
Recent isothiocyanate covalent labeling studies have suggested that a classical cannabinoid, (-)-7'-isothiocyanato-11-hydroxy-1',1'dimethylheptyl-hexahydrocannabinol (AM841), enters the cannabinoid CB2 receptor via the lipid bilayer (Pei, Y., Mercier, R. W., Anday, J. K., Thakur, G. A., Zvonok, A. M., Hurst, D., Reggio, P. H., Janero, D. R., and Makriyannis, A. (2008) Chem. Biol. 15, 1207-1219). However, the sequence of steps involved in such a lipid pathway entry has not yet been elucidated. Here, we test the hypothesis that the endogenous cannabinoid sn-2-arachidonoylglycerol (2-AG) attains access to the CB2 receptor via the lipid bilayer. To this end, we have employed microsecond time scale all-atom molecular dynamics (MD) simulations of the interaction of 2-AG with CB2 via a palmitoyl-oleoyl-phosphatidylcholine lipid bilayer. Results suggest the following: 1) 2-AG first partitions out of bulk lipid at the transmembrane alpha-helix (TMH) 6/7 interface; 2) 2-AG then enters the CB2 receptor binding pocket by passing between TMH6 and TMH7; 3) the entrance of the 2-AG headgroup into the CB2 binding pocket is sufficient to trigger breaking of the intracellular TMH3/6 ionic lock and the movement of the TMH6 intracellular end away from TMH3; and 4) subsequent to protonation at D3.49/D6.30, further 2-AG entry into the ligand binding pocket results in both a W6.48 toggle switch change and a large influx of water. To our knowledge, this is the first demonstration via unbiased molecular dynamics that a ligand can access the binding pocket of a class A G protein-coupled receptor via the lipid bilayer and the first demonstration via molecular dynamics of G protein-coupled receptor activation triggered by a ligand binding event.
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Affiliation(s)
- Dow P. Hurst
- From the Department of Chemistry and Biochemistry, Center for Drug Discovery, University of North Carolina, Greensboro, North Carolina 27402
| | - Alan Grossfield
- the Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642
| | - Diane L. Lynch
- From the Department of Chemistry and Biochemistry, Center for Drug Discovery, University of North Carolina, Greensboro, North Carolina 27402
| | - Scott Feller
- the Department of Chemistry, Wabash College, Crawfordsville, Indiana 47933
| | - Tod D. Romo
- the Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642
| | - Klaus Gawrisch
- Membrane Biochemistry/Biophysics, NIAAA, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Michael C. Pitman
- the Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598
| | - Patricia H. Reggio
- From the Department of Chemistry and Biochemistry, Center for Drug Discovery, University of North Carolina, Greensboro, North Carolina 27402
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Hurst DP, Whitnell RM, Lynch DL, Reggio PH. Peptide Binding Site Determination Using Conformational Memories and MMC. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.3130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Nebane NM, Hurst DP, Carrasquer CA, Qiao Z, Reggio PH, Song ZH. Residues accessible in the binding-site crevice of transmembrane helix 6 of the CB2 cannabinoid receptor. Biochemistry 2009; 47:13811-21. [PMID: 19053233 DOI: 10.1021/bi8007802] [Citation(s) in RCA: 21] [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: 01/21/2023]
Abstract
We have used the substituted-cysteine accessibility method (SCAM) to map the residues in the sixth membrane-spanning segment of the CB2 cannabinoid receptor that contribute to the surface of the water-accessible binding-site crevice. Using a background of the mutant C2.59S which is relatively insensitive to the methanethiosulfonate (MTS) reagents, we mutated to cysteine, one at a time, 34 consecutive residues in TMH6 of the CB2 receptor. These mutant receptors were then expressed in HEK293 cells. By incubating HEK293 cells stably transfected with CB2 receptors with the small, charged, hydrophilic, thiol-specific reagent methanethiosulfonate ethylammonium (MTSEA), [(3)H]CP55940 binding was significantly inhibited for six mutant receptors. All six of the mutants that reacted with MTSEA were protected from the reaction when pretreated with the cannabinoid agonist WIN55212-2, suggesting that MTSEA modification occurred within the binding crevice. Therefore, the side chains of the residues at these reactive loci (V6.51, L6.52, L6.54, M6.55, L6.59, and T6.62) are on the water-accessible surface of the binding-site crevice. These residues are extracellular to the TMH6 CWXP hinge motif. The pattern of accessibility is consistent with a alpha-helical conformation for this segment of TMH6. Molecular modeling studies performed in the context of the CB2 model show that V6.51, L6.52, L6.54, M6.55, L6.59, and T6.62 face into the CB2 binding pocket, further confirming our SCAM results. These results are similar to the accessibility patterns determined by SCAM studies of TMH6 in the opioid and dopamine D2 receptors.
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Affiliation(s)
- Ntsang M Nebane
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky 40292, USA
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Abstract
Conformational Memories (CM) is a simulated annealing/Monte Carlo method that explores peptide and protein dihedral conformational space completely and efficiently, independent of the original conformation. Here we extend the CM method to include the variation of a randomly chosen bond angle, in addition to the standard variation of two or three randomly chosen dihedral angles, in each Monte Carlo trial of the CM exploratory and biased phases. We test the hypothesis that the inclusion of variable bond angles in CM leads to an improved sampling of conformational space. We compare the results with variable bond angles to CM with no bond angle variation for the following systems: (1) the pentapeptide Met-enkephalin, which is a standard test case for conformational search methods; (2) the proline ring pucker in a 17mer model peptide, (Ala)(8)Pro(Ala)(8); and (3) the conformations of the Ser 7.39 chi(1) in transmembrane helix 7 (TMH7) of the cannabinoid CB1 receptor, a 25-residue system. In each case, analysis of the CM results shows that the inclusion of variable bond angles results in sampling of regions of conformational space that are inaccessible to CM calculations with only variable dihedral angles, and/or a shift in conformational populations from those calculated when variable bond angles are not included. The incorporation of variable bond angles leads to an improved sampling of conformational space without loss of efficiency. Our examples show that this improved sampling leads to better exploration of biologically relevant conformations that have been experimentally validated.
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Affiliation(s)
- Robert M Whitnell
- Chemistry Department, Guilford College, Greensboro, North Carolina 27410, USA.
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Fan H, Kotsikorou E, Hoffman AF, Ravert HT, Holt D, Hurst DP, Lupica CR, Reggio PH, Dannals RF, Horti AG. Analogs of JHU75528, a PET ligand for imaging of cerebral cannabinoid receptors (CB1): development of ligands with optimized lipophilicity and binding affinity. Eur J Med Chem 2008; 44:593-608. [PMID: 18511157 DOI: 10.1016/j.ejmech.2008.03.040] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 03/21/2008] [Accepted: 03/27/2008] [Indexed: 11/16/2022]
Abstract
Cyano analogs of Rimonabant with high binding affinity for the cerebral cannabinoid receptor (CB1) and with optimized lipophilicity have been synthesized as potential positron emission tomography (PET) ligands. The best ligands of the series are optimal targets for the future radiolabeling with PET isotopes and in vivo evaluation as radioligands with enhanced properties for PET imaging of CB1 receptors in human subjects. Extracellular electrophysiological recordings in rodent brain slices demonstrated that JHU75528, 4, the lead compound of the new series, has functional CB antagonist properties that are consistent with its structural relationship to Rimonabant. Molecular modeling analysis revealed an important role of the binding of the cyano group with the CB1 binding pocket.
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Affiliation(s)
- Hong Fan
- PET Center, Division of Nuclear Medicine, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Anavi-Goffer S, Fleischer D, Hurst DP, Lynch DL, Barnett-Norris J, Shi S, Lewis DL, Mukhopadhyay S, Howlett AC, Reggio PH, Abood ME. Helix 8 Leu in the CB1 cannabinoid receptor contributes to selective signal transduction mechanisms. J Biol Chem 2007; 282:25100-13. [PMID: 17595161 DOI: 10.1074/jbc.m703388200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [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: 11/06/2022] Open
Abstract
The intracellular C-terminal helix 8 (H8) of the CB(1) cannabinoid receptor deviates from the highly conserved NPXXY(X)(5,6)F G-protein-coupled receptor motif, possessing a Leu instead of a Phe. We compared the signal transduction capabilities of CB(1) with those of an L7.60F mutation and an L7.60I mutation that mimics the CB(2) sequence. The two mutant receptors differed from wild type (WT) in their ability to regulate G-proteins in the [(35)S]guanosine 5'-3-O-(thio)triphosphate binding assay. The L7.60F receptor exhibited attenuated stimulation by agonists WIN-55,212-2 and CP-55,940 but not HU-210, whereas the L7.60I receptor exhibited impaired stimulation by all agonists tested as well as by the inverse agonist rimonabant. The mutants internalized more rapidly than WT receptors but could equally sequester G-proteins from the somatostatin receptor. Both the time course and maximal N-type Ca(2+) current inhibition by WIN-55,212-2 were reduced in the mutants. Reconstitution experiments with pertussis toxin-insensitive G-proteins revealed loss of coupling to Galpha(i3) but not Galpha(0A) in the L7.60I mutant, whereas the reduction in the time course for the L7.60F mutant was governed by Galpha(i3). Furthermore, Galpha(i3) but not Galpha(0A) enhanced basal facilitation ratio, suggesting that Galpha(i3) is responsible for CB(1) tonic activity. Co-immunoprecipitation studies revealed that both mutant receptors were associated with Galpha(i1) or Galpha(i2) but not with Galpha(i3). Molecular dynamics simulations of WT CB(1) receptor and each mutant in a 1-palmitoyl-2-oleoylphosphatidylcholine bilayer suggested that the packing of H8 is different in each. The hydrogen bonding patterns along the helix backbones of each H8 also are different, as are the geometries of the elbow region of H8 (R7.56(400)-K7.58(402)). This study demonstrates that the evolutionary modification to NPXXY(X)(5,6)L contributes to maximal activity of the CB(1) receptor and provides a molecular basis for the differential coupling observed with chemically different agonists.
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Affiliation(s)
- Sharon Anavi-Goffer
- California Pacific Medical Center Research Institute, San Francisco, California 94107, USA
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