1
|
Esaki H, Deyama S, Izumi S, Katsura A, Nishikawa K, Nishitani N, Kaneda K. Varenicline enhances recognition memory via α7 nicotinic acetylcholine receptors in the medial prefrontal cortex in male mice. Neuropharmacology 2023; 239:109672. [PMID: 37506875 DOI: 10.1016/j.neuropharm.2023.109672] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 07/30/2023]
Abstract
Previous studies postulated that chronic administration of varenicline, a partial and full agonist at α4β2 and α7 nicotinic acetylcholine receptors (nAChRs), respectively, enhances recognition memory. However, whether its acute administration is effective, on which brain region(s) it acts, and in what signaling it is involved, remain unknown. To address these issues, we conducted a novel object recognition test using male C57BL/6J mice, focusing on the medial prefrontal cortex (mPFC), a brain region associated with nicotine-induced enhancement of recognition memory. Systemic administration of varenicline before the training dose-dependently enhanced recognition memory. Intra-mPFC varenicline infusion also enhanced recognition memory, and this enhancement was blocked by intra-mPFC co-infusion of a selective α7, but not α4β2, nAChR antagonist. Consistent with this, intra-mPFC infusion of a selective α7 nAChR agonist augmented object recognition memory. Furthermore, intra-mPFC co-infusion of U-73122, a phospholipase C (PLC) inhibitor, or 2-aminoethoxydiphenylborane (2-APB), an inositol trisphosphate (IP3) receptor inhibitor, suppressed the varenicline-induced memory enhancement, suggesting that α7 nAChRs may also act as Gq-coupled metabotropic receptors. Additionally, whole-cell recordings from mPFC layer V pyramidal neurons in vitro revealed that varenicline significantly increased the summation of evoked excitatory postsynaptic potentials, and this effect was suppressed by U-73122 or 2-APB. These findings suggest that varenicline might acutely enhance recognition memory via mPFC α7 nAChR stimulation, followed by mPFC neuronal excitation, which is mediated by the activation of PLC and IP3 receptor signaling. Our study provides evidence supporting the potential repositioning of varenicline as a treatment for cognitive impairment.
Collapse
Affiliation(s)
- Hirohito Esaki
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Satoshi Deyama
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Shoma Izumi
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Ayano Katsura
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Keisuke Nishikawa
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Naoya Nishitani
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Katsuyuki Kaneda
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan.
| |
Collapse
|
2
|
Nasrin S, Islam MN, Tayab MA, Nasrin MS, Siddique MAB, Emran TB, Reza ASMA. Chemical profiles and pharmacological insights of Anisomeles indica Kuntze: An experimental chemico-biological interaction. Pharmacotherapy 2022; 149:112842. [PMID: 35325851 DOI: 10.1016/j.biopha.2022.112842] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 12/22/2022]
Abstract
Anisomeles indica (L.) Kuntze is an ethnomedicinally important plant that has long been used in traditional medicine to treat a variety of ailments, including dyspepsia, abdominal pain, colic, allergies, inflammation, and rheumatic arthritis. However, the scientific framework underlying these medicinal properties is not well known. This study aimed to investigate the antidepressive, antidiarrheal, thrombolytic, and anti-inflammatory potential of a methanol extract of A. indica (MeOH-AI). The potential bioactive compounds in the MeOH-AI were identified using gas chromatography-mass spectrometry (GC-MS), and antidepressant activities were evaluated using the tail suspension test (TST) and forced swim test (FST). Antidiarrheal effects were also assayed in castor oil-induced diarrhea and gastrointestinal motility studies. The anti-inflammatory activities were explored by examining the effects on protein inhibition and denaturation in heat- and hypotonic solution-induced hemolysis assays. The thrombolytic activity was evaluated using the clot lysis test in human blood. BIOVIA and Schrödinger Maestro (v11.1) were applied for docking analysis to determine binding interactions, and the absorption, distribution, metabolisms, excretion/toxicity (ADME/T) properties of bioactive compounds were explored using a web-based method. The GC-MS analysis of MeOH-AI revealed the presence of several bioactive compounds. MeOH-AI administration resulted in significant (p < 0.01) reductions in the immobility times for both the FST and TST compared with those in the control group. MeOH-AI also induced significant (p < 0.01) reductions in castor oil-induced diarrhea severity and gastrointestinal motility in a mouse model. In addition, the in vitro anti-inflammatory and thrombolytic activity studies produced remarkable responses. The binding assay showed that 4-dehydroxy-N-(4,5-methylenedioxy-2-nitrobenzylidene) tyramine interacts favorably with monoamine oxidase and serotonin and M3 muscarinic acetylcholine receptors, displaying good pharmacokinetic properties, which may mediate the effects of MeOH-AI on depression and diarrhea. Overall, the research findings indicated that MeOH-AI has significant antidepressant, antidiarrheal, and anti-inflammatory effects and may represent an alternative source of novel therapeutic factors.
Collapse
Affiliation(s)
- Suaad Nasrin
- Department of Pharmacy, International Islamic University Chittagong, Chittagong 4318, Bangladesh
| | - Mohammad Nazmul Islam
- Department of Pharmacy, International Islamic University Chittagong, Chittagong 4318, Bangladesh
| | - Mohammed Abu Tayab
- Department of Pharmacy, International Islamic University Chittagong, Chittagong 4318, Bangladesh
| | - Mst Samima Nasrin
- Department of Pharmacy, International Islamic University Chittagong, Chittagong 4318, Bangladesh; Department of Biochemistry and Molecular Biology, University of Chittagong, Chittagong 4331, Bangladesh
| | - Md Abu Bakar Siddique
- Institute of National Analytical Research and Service (INARS), Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka 1205, Bangladesh
| | - Talha Bin Emran
- Department of Pharmacy, BGC Trust University Bangladesh, Chittagong 4381, Bangladesh; Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, Dhaka 1207, Bangladesh.
| | - A S M Ali Reza
- Department of Pharmacy, International Islamic University Chittagong, Chittagong 4318, Bangladesh; Department of Biochemistry and Molecular Biology, University of Chittagong, Chittagong 4331, Bangladesh.
| |
Collapse
|
3
|
Alam MM, Emon NU, Alam S, Rudra S, Akhter N, Mamun MMR, Ganguly A. Assessment of pharmacological activities of Lygodium microphyllum Cav. leaves in the management of pain, inflammation, pyrexia, diarrhea, and helminths: In vivo, in vitro and in silico approaches. Biomed Pharmacother 2021; 139:111644. [PMID: 33945914 DOI: 10.1016/j.biopha.2021.111644] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/06/2021] [Accepted: 04/19/2021] [Indexed: 11/18/2022] Open
Abstract
Lygodium microphyllum Cav. (Family: Lygodiaceae) is a perennial, snake fern and an invasive weed in Florida and also known as old world climbing fern. This study is intended to evaluate the antipyretic, analgesic, anti-inflammatory, antidiarrheal and anthelmintic activity of methanol extract of Lygodium microphyllum Cav. leaves (MELM) by in vivo, in vitro and in silico approaches. In addition, Biovia, PyRx autoDock Vina, UCSF Chimera have been applied to investigate the docking study in order to evaluate the binding interaction and an online tool was used to explore the ADME/T properties of selected bioactive compounds. In acetic acid induced writhing study, MELM inhibited 44.28% and 56.61% of writhes at 200 and 400 (mg/kg) respectively compared to standard drug Diclofenac-Na (10 mg/kg) (74.42% inhibition). In anti-inflammatory experiment by formalin triggered licking method, MELM caused significant (p < 0.05) inhibition of licking in both early phase (42.97%, 63.30%) and late phase (43.35%, 63.03%) at the doses of 200 and 400 mg/kg respectively, whereas reference drug Ibuprofen inhibited paw licking 77.18% in early phase and 76.86% in late phase. MELM also showed promising antipyretic potential where the maximum reduction of fever was produced by MELM 400 mg/kg whose fever lowering capacity is close to the prescribe drug Indomethacin 4 mg/kg, i.p. In Castor oil triggered diarrhea method, MELM delayed the onset time of diarrhea, continuous persistence of wet feces, and decreased the weight of wet feces remarkably. Defection inhibition was achieved 27.56% and 51.72%, for MELM 200 and at 400 (mg/kg) respectively while loperamide 2 (mg/kg) yields 55.17% inhibition of the diarrheal defecation. In anthelmintic bioassay, MELM took 5.83 ± 0.83 and 41.67 ± 1.78 min respectively for paralyzing and death compared to standard drug albendazole; (paralysis time 4.00 ± 0.73 min and death time 31,00 ± 1.71 min). Isoeleutherol, isoquercetin and quercetin were found prominent in molecular docking study and ADME/T analysis verified their drug likeliness. The research validates the moderate analgesic, anti-inflammatory, and remarkable antipyretic, antidiarrheal, anthelmintic activities of the plant extract which can be used an alternative source of novel therapeutics.
Collapse
Affiliation(s)
- Md Munsur Alam
- Department of Pharmacy, Faculty of Science and Engineering, International Islamic University Chittagong, Chattogram 4318, Bangladesh
| | - Nazim Uddin Emon
- Department of Pharmacy, Faculty of Science and Engineering, International Islamic University Chittagong, Chattogram 4318, Bangladesh; Department of Public Health, School of Science and Technology, Bangladesh Open University, Gazipur 1705, Bangladesh
| | - Safaet Alam
- Department of Pharmacy, State University of Bangladesh, 77 Satmasjid road, Dhanmondi, Dhaka 1207, Bangladesh; Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh.
| | - Sajib Rudra
- Department of Botany, Faculty of Biological Science, University of Chittagong, Chattogram 4331, Bangladesh
| | - Nahid Akhter
- Department of Pharmacy, Faculty of Science and Engineering, International Islamic University Chittagong, Chattogram 4318, Bangladesh
| | - Md Masudur Rahman Mamun
- Department of Pharmacy, Faculty of Science and Engineering, International Islamic University Chittagong, Chattogram 4318, Bangladesh
| | - Amlan Ganguly
- Department of Clinical Pharmacy and Pharmacology, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh
| |
Collapse
|
4
|
Alam S, Emon NU, Shahriar S, Richi FT, Haque MR, Islam MN, Sakib SA, Ganguly A. Pharmacological and computer-aided studies provide new insights into Millettia peguensis Ali (Fabaceae). Saudi Pharm J 2020; 28:1777-1790. [PMID: 33424267 PMCID: PMC7783235 DOI: 10.1016/j.jsps.2020.11.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 11/12/2020] [Indexed: 12/11/2022] Open
Abstract
Millettia peguensis, popular for its ethnopharmacological uses, was employed to evaluate its different pharmacological properties in this study. The analgesic studies of the plant have been performed by acetic acid-induced writhing and formalin-induced licking tests respectively, whereas the antidiarrheal experiment was done by castor oil-induced diarrheal test. Besides, antioxidant, cytotoxic, antimicrobial, thrombolytic evaluations were performed by DPPH scavenging with phenol content determination, brine shrimp lethality, disc diffusion and clot lysis methods respectively. Moreover, in silico study of the phytoconstituents was carried out by molecular docking and ADME/T analysis. The methanol extract of Millettia peguensis (MEMP) revealed significant biological activity in the analgesic and antidiarrheal test (p < 0.001) compared to the standards. Antioxidant assay displayed promising IC50 values (15.96 μg/mL) with the total phenol content (65.27 ± 1.24 mg GAE/g). In the cytotoxicity study, the LC50 value was found to be 1.094 μg/mL. Besides, MEMP was highly sensitive to the bacteria but less liable to clot lysis. Furthermore, phytoconstituents exposed potential binding affinity towards the selected receptors, whereas the ADME/T properties indicated the drug likeliness of the plant. The outcomes of these findings suggest the therapeutic potential of this plant against pain, diarrhea, inflammation, and tissue toxicity.
Collapse
Key Words
- 5-HT3, 5-hydroxytryptamine 3
- ASA, acetyl salicylic acid
- Analgesic
- Antidiarrheal
- Antioxidant
- Antitumor
- BHT, butylated hydroxytoluene
- CADD, computer-aided drug discovery
- COX 1, cyclooxygenase-1
- COX 2, cyclooxygenase-2
- DPPH, 2,2-diphenyl-1-picryl-hydrazyl-hydrate
- GABA, gamma-Aminobutyric acid
- IC50, half maximal inhibitory concentration
- IL-1, interleukin-1
- LC50, Lethal Concentration 50
- MEMP, methanol extract of Millettia peguensis
- MMP 9, matrix metalloproteinase 9
- Millettia peguensis
- NF-κB, nuclear factor kappa-light-chain-enhancer of activated B cells
- RONS, reactive oxygen and nitrogen species
- ROS, reactive oxygen species
- TNF-alpha, tumour necrosis factor alpha
Collapse
Affiliation(s)
- Safaet Alam
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh
| | - Nazim Uddin Emon
- Department of Pharmacy, Faculty of Science and Engineering, International Islamic University Chittagong, Chittagong 4318, Bangladesh
| | - Saimon Shahriar
- Department of Pharmacy, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh
| | - Fahmida Tasnim Richi
- Department of Pharmacy, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh
| | - Mohammad Rashedul Haque
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh
| | - Mohammad Nazmul Islam
- Department of Pharmacy, Faculty of Science and Engineering, International Islamic University Chittagong, Chittagong 4318, Bangladesh
| | - Shahenur Alam Sakib
- Department of Pharmacy, Faculty of Science and Engineering, International Islamic University Chittagong, Chittagong 4318, Bangladesh
| | - Amlan Ganguly
- Department of Clinical Pharmacy and Pharmacology, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh
| |
Collapse
|
5
|
Rudra S, Tahamina A, Emon NU, Adnan M, Shakil M, Chowdhury MHU, Barlow JW, Alwahibi MS, Soliman Elshikh M, Faruque MO, Uddin SB. Evaluation of Various Solvent Extracts of Tetrastigma leucostaphylum (Dennst.) Alston Leaves, a Bangladeshi Traditional Medicine Used for the Treatment of Diarrhea. Molecules 2020; 25:molecules25214994. [PMID: 33126608 PMCID: PMC7662597 DOI: 10.3390/molecules25214994] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/24/2020] [Accepted: 10/26/2020] [Indexed: 12/23/2022] Open
Abstract
Tetrastigma leucostaphylum (TL) is an important ethnic medicine of Bangladesh used to treat diarrhea and dysentery. Hence, current study has been designed to characterize the antidiarrheal (in vivo) and cytotoxic (in vitro) effects of T. leucostaphylum. A crude extract was prepared with methanol (MTL) and further partitioned into n-hexane (NTL), dichloromethane (DTL), and n-butanol (BTL) fractions. Antidiarrheal activity was investigated using castor oil induced diarrhea, enteropooling, and gastrointestinal transit models, while cytotoxicity was evaluated using the brine shrimp lethality bioassay. In antidiarrheal experiments, all doses (100, 200, and 400 mg/kg) of the DTL extract significantly reduced diarrheal stool frequency, volume and weight of intestinal contents, and gastrointestinal motility in mice. Similarly, in the cytotoxicity assay, all extracts exhibited activity, with the DTL extract the most potent (LC50 67.23 μg/mL). GC-MS analysis of the DTL extract identified 10 compounds, which showed good binding affinity toward M3 muscarinic acetylcholine, 5-HT3, Gut inhibitory phosphodiesterase, DNA polymerase III subunit alpha, and UDP-N-acetylglucosamine-1 carboxyvinyltransferase enzyme targets upon molecular docking analysis. Although ADME/T analyses predicted the drug-likeness and likely safety upon consumption of these bioactive compounds, significant toxicity concerns are evident due to the presence of the known phytotoxin, 2,4-di-tert-butylphenol. In summary, T. leucostaphylum showed promising activity, helping to rationalize the ethnomedicinal use and importance of this plant, its safety profile following both acute and chronic exposure warrants further investigation.
Collapse
Affiliation(s)
- Sajib Rudra
- Ethnobotany and Pharmacognosy Lab, Department of Botany, University of Chittagong, Chattogram 4331, Bangladesh; (S.R.); (A.T.); (M.S.); (M.H.U.C.)
| | - Afroza Tahamina
- Ethnobotany and Pharmacognosy Lab, Department of Botany, University of Chittagong, Chattogram 4331, Bangladesh; (S.R.); (A.T.); (M.S.); (M.H.U.C.)
| | - Nazim Uddin Emon
- Department of Public Health, School of Science and Technology, Bangladesh Open University, Gazipur 1705, Dhaka, Bangladesh;
| | - Md. Adnan
- Department of Bio-Health Technology, College of Biomedical Science, Kangwon National University, Chuncheon 24341, Korea;
| | - Mohammad Shakil
- Ethnobotany and Pharmacognosy Lab, Department of Botany, University of Chittagong, Chattogram 4331, Bangladesh; (S.R.); (A.T.); (M.S.); (M.H.U.C.)
| | - Md. Helal Uddin Chowdhury
- Ethnobotany and Pharmacognosy Lab, Department of Botany, University of Chittagong, Chattogram 4331, Bangladesh; (S.R.); (A.T.); (M.S.); (M.H.U.C.)
| | - James W. Barlow
- Department of Chemistry, Royal College Surgeons, Dublin D02YN77, Ireland;
| | - Mona S. Alwahibi
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia; (M.S.A.); (M.S.E.)
| | - Mohamed Soliman Elshikh
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia; (M.S.A.); (M.S.E.)
| | - Mohammad Omar Faruque
- Ethnobotany and Pharmacognosy Lab, Department of Botany, University of Chittagong, Chattogram 4331, Bangladesh; (S.R.); (A.T.); (M.S.); (M.H.U.C.)
- Correspondence: (M.O.F.); (S.B.U.); Tel.: +88-018-1839-7345 (M.O.F.); +88-017-1106-5377 (S.B.U.)
| | - Shaikh Bokhtear Uddin
- Ethnobotany and Pharmacognosy Lab, Department of Botany, University of Chittagong, Chattogram 4331, Bangladesh; (S.R.); (A.T.); (M.S.); (M.H.U.C.)
- Correspondence: (M.O.F.); (S.B.U.); Tel.: +88-018-1839-7345 (M.O.F.); +88-017-1106-5377 (S.B.U.)
| |
Collapse
|
6
|
Mukherjee S, Erramilli SK, Ammirati M, Alvarez FJD, Fennell KF, Purdy MD, Skrobek BM, Radziwon K, Coukos J, Kang Y, Dutka P, Gao X, Qiu X, Yeager M, Eric Xu H, Han S, Kossiakoff AA. Synthetic antibodies against BRIL as universal fiducial marks for single-particle cryoEM structure determination of membrane proteins. Nat Commun 2020; 11:1598. [PMID: 32221310 PMCID: PMC7101349 DOI: 10.1038/s41467-020-15363-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 03/03/2020] [Indexed: 12/22/2022] Open
Abstract
We propose the concept of universal fiducials based on a set of pre-made semi-synthetic antibodies (sABs) generated by customized phage display selections against the fusion protein BRIL, an engineered variant of apocytochrome b562a. These sABs can bind to BRIL fused either into the loops or termini of different GPCRs, ion channels, receptors and transporters without disrupting their structure. A crystal structure of BRIL in complex with an affinity-matured sAB (BAG2) that bound to all systems tested delineates the footprint of interaction. Negative stain and cryoEM data of several examples of BRIL-membrane protein chimera highlight the effectiveness of the sABs as universal fiducial marks. Taken together with a cryoEM structure of sAB bound human nicotinic acetylcholine receptor, this work demonstrates that these anti-BRIL sABs can greatly enhance the particle properties leading to improved cryoEM outcomes, especially for challenging membrane proteins.
Collapse
Affiliation(s)
- Somnath Mukherjee
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Satchal K Erramilli
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Mark Ammirati
- Medicine Design, Worldwide Research and Development, Pfizer Inc., Eastern Point Road, Groton, CT, 06340, USA
| | - Frances J D Alvarez
- Medicine Design, Worldwide Research and Development, Pfizer Inc., Eastern Point Road, Groton, CT, 06340, USA
| | - Kimberly F Fennell
- Medicine Design, Worldwide Research and Development, Pfizer Inc., Eastern Point Road, Groton, CT, 06340, USA
| | - Michael D Purdy
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Blazej M Skrobek
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
- Gene Center and Department of Biochemistry, Ludwig Maximilian University of Munich, Munich, Germany
| | - Katarzyna Radziwon
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
- Department of Biochemistry, University of Wisconsin Madison, Madison, WI, USA
| | - John Coukos
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Yanyong Kang
- Center for Cancer and Cell Biology, Structural Biology Program, Van Andel Research Institute, Grand Rapids, MI, USA
- Takeda San Diego Inc., San Diego, CA, USA
| | - Przemysław Dutka
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Xiang Gao
- Center for Cancer and Cell Biology, Structural Biology Program, Van Andel Research Institute, Grand Rapids, MI, USA
| | - Xiayang Qiu
- Medicine Design, Worldwide Research and Development, Pfizer Inc., Eastern Point Road, Groton, CT, 06340, USA
| | - Mark Yeager
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - H Eric Xu
- Center for Cancer and Cell Biology, Structural Biology Program, Van Andel Research Institute, Grand Rapids, MI, USA
- Key Laboratory of Receptor Research, VARI-SIMM Center, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Seungil Han
- Medicine Design, Worldwide Research and Development, Pfizer Inc., Eastern Point Road, Groton, CT, 06340, USA
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA.
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA.
| |
Collapse
|
7
|
Unveiling Pharmacological Responses and Potential Targets Insights of Identified Bioactive Constituents of Cuscuta reflexa Roxb. Leaves through In Vivo and In Silico Approaches. Pharmaceuticals (Basel) 2020; 13:ph13030050. [PMID: 32245131 PMCID: PMC7151675 DOI: 10.3390/ph13030050] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 01/02/2023] Open
Abstract
Cuscuta reflexa Roxb. is traditionally used by the indigenous communities of Bangladesh to treat different diseases, such as pain, edema, tumor, jaundice, and skin infections. This study tested neuro-pharmacological, anti-nociceptive, and antidiarrheal activities by in vivo and in silico experiments for the metabolites extracted (methanol) from the leaves of Cuscuta reflexa (MECR). During the anxiolytic evaluation analyzed by elevated plus maze and hole board tests, MECR (200 and 400 mg/kg) exhibited a significant dose-dependent reduction of anxiety-like behavior in mice. Similarly, mice treated with MECR demonstrated a dose-dependent decrease in the time of immobility in both forced swimming and tail suspension tests. In addition, anti-nociceptive activity was assessed by the chemical-induced (acetic acid and formalin) pain models. In both cases, 400 mg/kg was found to be most effective and significantly (p < 0.001) inhibited acetic acid stimulated writhing and formalin-induced licking (pain response) in mice. Furthermore, antidiarrheal efficacy determined by the castor-oil induced diarrheal model manifested an evident inhibition of diarrheal stool frequency. In parallel, previously isolated bioactive compounds were documented based on the biological activities and subjected to in silico studies to correlate with the current pharmacological outcomes. The selected isolated compounds (15) displayed favorable binding affinities to potassium channels, human serotonin receptor, COX-1, COX-2, M3 muscarinic acetylcholine receptor, and 5-HT3 receptor proteins. Additionally, the ADME/T and toxicological properties were justified to unveil their drug-like properties and toxicity level. Overall, Cuscuta reflexa is bioactive and could be a potential source for the development of alternative medicine.
Collapse
|
8
|
Munro L, Ladefoged LK, Padmanathan V, Andersen S, Schiøtt B, Kristensen AS. Conformational Changes in the 5-HT 3A Receptor Extracellular Domain Measured by Voltage-Clamp Fluorometry. Mol Pharmacol 2019; 96:720-734. [PMID: 31582575 DOI: 10.1124/mol.119.116657] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 09/28/2019] [Indexed: 01/13/2023] Open
Abstract
The 5-hydroxytryptamine (5-HT) type 3 receptor is a member of the cysteine (Cys)-loop receptor super family of ligand-gated ion channels in the nervous system and is a clinical target in a range of diseases. The 5-HT3 receptor mediates fast serotonergic neurotransmission by undergoing a series of conformational changes initiated by ligand binding that lead to the rapid opening of an intrinsic cation-selective channel. However, despite the availability of high-resolution structures of a mouse 5-HT3 receptor, many important aspects of the mechanistic basis of 5-HT3 receptor function and modulation by drugs remain poorly understood. In particular, there is little direct evidence for the specific conformational changes predicted to occur during ligand-gated channel activation and desensitization. In the present study, we used voltage-clamp fluorometry (VCF) to measure conformational changes in regions surrounding the orthosteric binding site of the human 5-HT3A (h5-HT3A) receptor during binding of 5-HT and different classes of 5-HT3 receptor ligands. VCF utilizes parallel measurements of receptor currents with photon emission from fluorescent reporter groups covalently attached to specific positions in the receptor structure. Reporter groups that are highly sensitive to the local molecular environment can, in real time, report conformational changes as changes in fluorescence that can be correlated with changes in receptor currents reporting the functional states of the channel. Within the loop C, D, and E regions that surround the orthosteric binding site in the h5-HT3A receptor, we identify positions that are amenable to tagging with an environmentally sensitive reporter group that reports robust fluorescence changes upon 5-HT binding and receptor activation. We use these reporter positions to characterize the effect of ligand binding on the local structure of the orthosteric binding site by agonists, competitive antagonists, and allosterically acting channel activators. We observed that loop C appears to show distinct fluorescence changes for ligands of the same class, while loop D reports similar fluorescence changes for all ligands binding at the orthosteric site. In contrast, the loop E reporter position shows distinct changes for agonists, antagonists, and allosteric compounds, suggesting the conformational changes in this region are specific to ligand function. Interpretation of these results within the framework of current models of 5-HT3 and Cys-loop mechanisms are used to expand the understanding of how ligand binding in Cys-loop receptors relates to channel gating. SIGNIFICANCE STATEMENT: The 5-HT3 receptor is an important ligand-gated ion channel and drug target in the central and peripheral nervous system. Determining how ligand binding induced conformational changes in the receptor is central for understanding the structural mechanisms underlying 5-HT3 receptor function. Here, we employ voltage-gated fluorometry to characterize conformational changes in the extracellular domain of the human 5-HT3 receptor to identify intrareceptor motions during binding of a range of 5-HT3 receptor agonists and antagonists.
Collapse
Affiliation(s)
- Lachlan Munro
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Lucy Kate Ladefoged
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Vithushan Padmanathan
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Signe Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Birgit Schiøtt
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| | - Anders S Kristensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark (L.M., V.P., S.A., A.S.K.); and Department of Chemistry (L.K.L., B.S.) and Interdisciplinary Nanoscience Center (B.S.), Aarhus University, Aarhus, Denmark
| |
Collapse
|
9
|
Investigation of the Biological Activities and Characterization of Bioactive Constituents of Ophiorrhiza rugosa var. prostrata (D.Don) & Mondal Leaves through In Vivo, In Vitro, and In Silico Approaches. Molecules 2019; 24:molecules24071367. [PMID: 30965575 PMCID: PMC6480688 DOI: 10.3390/molecules24071367] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 03/29/2019] [Accepted: 04/04/2019] [Indexed: 11/17/2022] Open
Abstract
Ophiorrhiza rugosa var. prostrata is one of the most frequently used ethnomedicinal plants by the indigenous communities of Bangladesh. This study was designed to investigate the antidiarrheal, anti-inflammatory, anthelmintic and antibacterial activities of the ethanol extract of O. rugosa leaves (EEOR). The leaves were extracted with ethanol and subjected to in vivo antidiarrheal screening using the castor oil-induced diarrhea, enteropooling, and gastrointestinal transit models. Anti-inflammatory efficacy was evaluated using the histamine-induced paw edema test. In parallel, in vitro anthelmintic and antibacterial activities were evaluated using the aquatic worm and disc diffusion assays respectively. In all three diarrheal models, EEOR (100, 200 and 400 mg/kg) showed obvious inhibition of diarrheal stool frequency, reduction of the volume and weight of the intestinal contents, and significant inhibition of intestinal motility. Also, EEOR manifested dose-dependent anti-inflammatory activity. Anthelmintic action was deemed significant (P < 0.001) with respect to the onset of paralysis and helminth death. EEOR also resulted in strong zones of inhibition when tested against both Gram-positive and Gram-negative bacteria. GC-MS analysis identified 30 compounds within EEOR, and of these, 13 compounds documented as bioactive showed good binding affinities to M3 muscarinic acetylcholine, 5-HT3, tubulin and GlcN-6-P synthase protein targets in molecular docking experiments. Additionally, ADME/T and PASS analyses revealed their drug-likeness, likely safety upon consumption and possible pharmacological activities. In conclusion, our findings scientifically support the ethnomedicinal use and value of this plant, which may provide a potential source for future development of medicines.
Collapse
|
10
|
Potential roles of 5-HT 3 receptor (5-HT 3R) antagonists in modulating the effects of nicotine. Biomed Pharmacother 2019; 112:108630. [PMID: 30797147 DOI: 10.1016/j.biopha.2019.108630] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 01/17/2019] [Accepted: 01/28/2019] [Indexed: 12/22/2022] Open
Abstract
5-HT3R antagonists such as ondansetron, granisetron and tropisetron have been clinically used to treat nausea and vomiting in chemotherapy patients. However, current study and research revealed novel potentials of these ligands in other diseases like inflammation, Alzheimer's, and drug abuse. Towards utilising these drugs as anti-smoking agents to treat nicotine dependence problem, there are conflicting reports regarding the potential of these ligands in modulating the effects of nicotine in both human and animal behavioural studies. This is complicated by the heterogeneity of 5-HT3R itself, cross regulation between nicotinic acetylcholinergic receptor (nAChR) and distinct pharmacological profiles of 5-HT3R antagonists. This review gathered existing studies conducted investigating the potential of "-setron" class of 5-HT3R antagonists in modulating nicotine effects. We proposed that the mechanism where 5-HT3R antagonists mediate the effects of nicotine could be attributed by both direct at 5-HT3R and indirect mechanism in nicotine addiction downstream regulation. The indirect mechanism mediated by the 5-HT3R antagonist could be through α7 nAChR, 5-HT1B receptor (5-HT1BR), 5-HT1C receptor (5-HT1CR), calcineurin activity, p38 MAPK level, PPAR-γ and NF-κβ. Our review suggested that future studies should focus on newer 5-HT3R antagonist with superior pharmacological profile or the one with multitarget action rather than high selectivity at single receptor.
Collapse
|
11
|
Ladefoged LK, Munro L, Pedersen AJ, Lummis SCR, Bang-Andersen B, Balle T, Schiøtt B, Kristensen AS. Modeling and Mutational Analysis of the Binding Mode for the Multimodal Antidepressant Drug Vortioxetine to the Human 5-HT3A Receptor. Mol Pharmacol 2018; 94:1421-1434. [DOI: 10.1124/mol.118.113530] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/19/2018] [Indexed: 12/23/2022] Open
|
12
|
Impurity profiling of varenicline tartrate by LC-QTOF mass spectrometric techniques during drug development. J Pharm Biomed Anal 2018; 155:306-313. [DOI: 10.1016/j.jpba.2018.03.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 03/28/2018] [Accepted: 03/28/2018] [Indexed: 11/20/2022]
|
13
|
Basak S, Gicheru Y, Samanta A, Molugu SK, Huang W, Fuente MLD, Hughes T, Taylor DJ, Nieman MT, Moiseenkova-Bell V, Chakrapani S. Cryo-EM structure of 5-HT 3A receptor in its resting conformation. Nat Commun 2018; 9:514. [PMID: 29410406 PMCID: PMC5802770 DOI: 10.1038/s41467-018-02997-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 01/10/2018] [Indexed: 11/24/2022] Open
Abstract
Serotonin receptors (5-HT3AR) directly regulate gut movement, and drugs that inhibit 5-HT3AR function are used to control emetic reflexes associated with gastrointestinal pathologies and cancer therapies. The 5-HT3AR function involves a finely tuned orchestration of three domain movements that include the ligand-binding domain, the pore domain, and the intracellular domain. Here, we present the structure from the full-length 5-HT3AR channel in the apo-state determined by single-particle cryo-electron microscopy at a nominal resolution of 4.3 Å. In this conformation, the ligand-binding domain adopts a conformation reminiscent of the unliganded state with the pore domain captured in a closed conformation. In comparison to the 5-HT3AR crystal structure, the full-length channel in the apo-conformation adopts a more expanded conformation of all the three domains with a characteristic twist that is implicated in gating. Serotonin receptor (5-HT3AR), a pentameric ligand-gated ion channel, regulates numerous gastrointestinal functions. Here the authors provide a cryo-electron microscopic structure from the full-length 5-HT3AR in the apo-state which corresponds to a resting conformation of the channel.
Collapse
Affiliation(s)
- Sandip Basak
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, 44106-4970, USA
| | - Yvonne Gicheru
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, 44106-4970, USA
| | - Amrita Samanta
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, 44106-4970, USA
| | - Sudheer Kumar Molugu
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, 44106-4970, USA
| | - Wei Huang
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, 44106-4970, USA
| | - Maria la de Fuente
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, 44106-4970, USA
| | - Taylor Hughes
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, 44106-4970, USA
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, 44106-4970, USA
| | - Marvin T Nieman
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, 44106-4970, USA
| | - Vera Moiseenkova-Bell
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, 44106-4970, USA.,Department of Pharmacology, Case Western Reserve University, Cleveland, OH, 44106-4970, USA
| | - Sudha Chakrapani
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, 44106-4970, USA. .,Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106-4970, USA.
| |
Collapse
|
14
|
Czachowski CL, Froehlich JC, DeLory M. The Effects of Long-Term Varenicline Administration on Ethanol and Sucrose Seeking and Self-Administration in Male P Rats. Alcohol Clin Exp Res 2018; 42:453-460. [PMID: 29168193 PMCID: PMC5785421 DOI: 10.1111/acer.13562] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/16/2017] [Indexed: 01/23/2023]
Abstract
BACKGROUND Varenicline, a partial agonist at α4β2 and full agonist at α7 nicotinic cholinergic receptors, is FDA-approved for treatment of smoking cessation and has been found to reduce alcohol craving in clinical populations. In rodents, varenicline decreases free-choice ethanol (EtOH) intake with somewhat mixed findings in operant paradigms that utilize a combined appetitive/consummatory response. METHODS The present experiment utilized an operant paradigm that procedurally separates appetitive from consummatory responding and a "reward-blocking" approach (i.e., rats were able to consume EtOH during treatment) to better understand the efficacy of varenicline as a treatment for EtOH self-administration and subsequent EtOH seeking. Separate groups of EtOH- and sucrose-reinforced alcohol-preferring, male P rats experienced alternating cycles of vehicle (2-week cycles) and varenicline (0.3, 1.0, and 2.0 mg/kg self-administered in a gelatin preparation) treatment (3-week cycles) prior to daily sessions where a single lever press resulted in 20 minutes of reinforcer access. At the end of each cycle, a single extinction session assessed the seeking response in the absence of drug pretreatment. RESULTS Varenicline dose dependently decreased EtOH intake. Sucrose intake was largely unaffected, with no overall treatment effects and only sporadic days where the medium and high dose differed from vehicle. Neither sucrose nor EtOH seeking was significantly decreased by varenicline, and there were no treatment effects on either lick or lever-press latency. Overall effect sizes were much greater for both drinking and seeking in the EtOH group as compared to the sucrose group. CONCLUSIONS Varenicline effectively attenuates EtOH self-administration during treatment, but the experience with EtOH consumption while varenicline is "on board" is not sufficient to alter subsequent EtOH seeking. The overall pattern of findings indicates that varenicline blocks the rewarding properties of EtOH while not substituting for EtOH, that the nonspecific effects on an alternate reinforcer are negligible, and that blood levels of varenicline need to be maintained in order for treatment to remain effective.
Collapse
Affiliation(s)
- Cristine L Czachowski
- Department of Psychology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana
| | - Janice C Froehlich
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Michael DeLory
- Department of Psychology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana
| |
Collapse
|
15
|
Chen S, Bennet L, McGregor AL. Delayed Varenicline Administration Reduces Inflammation and Improves Forelimb Use Following Experimental Stroke. J Stroke Cerebrovasc Dis 2017; 26:2778-2787. [PMID: 28797614 DOI: 10.1016/j.jstrokecerebrovasdis.2017.06.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 05/21/2017] [Accepted: 06/29/2017] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Pharmacological activation of the cholinergic anti-inflammatory pathway (CAP), specifically by activating α7 nicotinic acetylcholine receptors, has been shown to confer short-term improvements in outcome. Most studies have investigated administration within 24 hours of stroke, and few have investigated drugs approved for use in human patients. We investigated whether delayed administration of varenicline, a high-affinity agonist at α7 nicotinic receptors and an established therapy for nicotine addiction, decreased brain inflammation and improved functional performance in a mouse model of experimental stroke. METHODS CSF-1R-EGFP (MacGreen) mice were subjected to transient middle cerebral artery occlusion and administered varenicline (2.5 mg/kg/d for 7 days) or saline (n = 10 per group) 3 days after stroke. Forelimb asymmetry was assessed in the Cylinder test every 2 days after surgery, and structural lesions were quantified at day 10. Enhanced green fluorescent protein (EGFP) and growth associated protein 43 (GAP43) immunohistochemistry were used to evaluate the effect of varenicline on inflammation and axonal regeneration, respectively. RESULTS Varenicline-treated animals showed a significant increase in impaired forelimb use compared with saline-treated animals 10 days after stroke. Varenicline treatment was associated with reduced EGFP expression and increased GAP43 expression in the striatum of MacGreen mice. CONCLUSION Our results show that delayed administration of varenicline promotes recovery of function following experimental stroke. Motor function improvements were accompanied by decreased brain inflammation and increased axonal regeneration in nonpenumbral areas. These results suggest that the administration of an exogenous nicotinic agonist in the subacute phase following stroke may be a viable therapeutic strategy for stroke patients.
Collapse
Affiliation(s)
- Siyi Chen
- School of Pharmacy, University of Auckland, Auckland, New Zealand; Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Ailsa L McGregor
- Centre for Brain Research, University of Auckland, Auckland, New Zealand; Division of Health Sciences, School of Pharmacy, University of Otago, Dunedin, New Zealand.
| |
Collapse
|
16
|
Price KL, Lillestol RK, Ulens C, Lummis SCR. Palonosetron-5-HT 3 Receptor Interactions As Shown by a Binding Protein Cocrystal Structure. ACS Chem Neurosci 2016; 7:1641-1646. [PMID: 27656911 DOI: 10.1021/acschemneuro.6b00132] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Palonosetron is a potent 5-HT3 receptor antagonist and an effective therapeutic agent against emesis. Here we identify the molecular determinants of compound recognition in the receptor binding site by obtaining a high resolution structure of palonosetron bound to an engineered acetylcholine binding protein that mimics the 5-HT3 receptor binding site, termed 5-HTBP, and by examining the potency of palonosetron in a range of 5-HT3 receptors with mutated binding site residues. The structural data indicate that palonosetron forms a tight and effective wedge in the binding pocket, made possible by its rigid tricyclic ring structure and its interactions with binding site residues; it adopts a binding pose that is distinct from the related antiemetics granisetron and tropisetron. The functional data show many residues previously shown to interact with agonists and antagonists in the binding site are important for palonosetron binding, and indicate those of particular importance are W183 (a cation-π interaction and a hydrogen bond) and Y153 (a hydrogen bond). This information, and the availability of the structure of palonosetron bound to 5-HTBP, should aid the development of novel and more efficacious drugs that act via 5-HT3 receptors.
Collapse
Affiliation(s)
- Kerry L. Price
- Department
of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, United Kingdom
| | - Reidun K. Lillestol
- Department
of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, United Kingdom
| | - Chris Ulens
- The
Laboratory of Structural Neurobiology, Department of Cellular and
Molecular Medicine, KU Leuven, Herestraat 49,
PB 601, B-3000 Leuven, Belgium
| | - Sarah C. R. Lummis
- Department
of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, United Kingdom
| |
Collapse
|
17
|
Reyes-Parada M, Iturriaga-Vasquez P. The development of novel polypharmacological agents targeting the multiple binding sites of nicotinic acetylcholine receptors. Expert Opin Drug Discov 2016; 11:969-81. [DOI: 10.1080/17460441.2016.1227317] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
18
|
Wu ZS, Cheng H, Jiang Y, Melcher K, Xu HE. Ion channels gated by acetylcholine and serotonin: structures, biology, and drug discovery. Acta Pharmacol Sin 2015; 36:895-907. [PMID: 26238288 PMCID: PMC4564887 DOI: 10.1038/aps.2015.66] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 06/24/2015] [Indexed: 12/17/2022] Open
Abstract
The nicotinic acetylcholine receptors (nAChRs) and the 5-HT3 receptors (5-HT3Rs) are cation-selective members of the pentameric ligand-gated ion channels (pLGICs), which are oligomeric protein assemblies that convert a chemical signal into an ion flux through postsynaptic membrane. They are critical components for synaptic transmission in the nervous system, and their dysfunction contributes to many neurological disorders. The diverse subunit compositions of pLGICs give rise to complex mechanisms of ligand recognition, channel gating, and ion-selective permeability, which have been demonstrated in numerous electrophysiological and molecular biological studies, and unraveled by progress in studying the structural biology of this protein family. In this review, we discuss recent insights into the structural and functional basis of two cation-selective pLGICs, the nAChR and the 5-HT3R, including their subunit compositions, ligand binding, and channel gating mechanisms. We also discuss their relevant pharmacology and drug discovery for treating various neurological disorders. Finally, we review a model of two alternative ion conducting pathways based on the latest 5-HT3A crystal structure.
Collapse
|