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Pei S, Xu C, Tan Y, Wang M, Yu J, Zhangsun D, Zhu X, Luo S. Synthesis, Activity, and Application of Fluorescent Analogs of [D1G, Δ14Q]LvIC Targeting α6β4 Nicotinic Acetylcholine Receptor. Bioconjug Chem 2023; 34:2194-2204. [PMID: 37748043 DOI: 10.1021/acs.bioconjchem.3c00283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
α6β4* nicotinic acetylcholine receptor (nAChR) (* represents the possible presence of additional subunits) is mainly distributed in the central and peripheral nervous system and is associated with neurological diseases, such as neuropathic pain; however, the ability to explore its function and distribution is limited due to the lack of pharmacological tools. As one of the analogs of α-conotoxin (α-CTx) LvIC from Conus lividus, [D1G, Δ14Q]LvIC (Lv) selectively and potently blocks α6/α3β4 nAChR (α6/α3 represents a chimera). Here, we synthesized three fluorescent analogs of Lv by connecting fluorescent molecules 6-carboxytetramethylrhodamine succinimidyl ester (6-TAMRA-SE, R), Cy3 NHS ester (Cy3, C) and BODIPY-FL NHS ester (BDP, B) to the N-terminus of the peptide and obtained Lv-R, Lv-C, and Lv-B, respectively. The potency and selectivity of three fluorescent peptides were evaluated using two-electrode voltage-clamp recording on nAChR subtypes expressed in Xenopus laevis oocytes, and the potency and selectivity of Lv-B were almost maintained with the half-maximal inhibition (IC50) of 64 nM. Then, we explored the stability of Lv-B in artificial cerebrospinal fluid and stained rat brain slices with Lv-B. The results indicated that the stability of Lv-B was slightly improved compared to that of native Lv. Additionally, we detected the distribution of the α6β4* nAChR subtype in the cerebral cortex using green fluorescently labeled peptide and fluorescence microscopy. Our findings not only provide a visualized pharmacological tool for exploring the distribution of the α6β4* nAChR subtype in various situ tissues and organs but also extend the application of α-CTx [D1G, Δ14Q]LvIC to demonstrate the involvement of α6β4 nAChR function in pathophysiology and pharmacology.
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Affiliation(s)
- Shengrong Pei
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Chenxing Xu
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Yao Tan
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Meiting Wang
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Jinpeng Yu
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Dongting Zhangsun
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
| | - Xiaopeng Zhu
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Sulan Luo
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
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Dong J, Zhang P, Xie J, Xie T, Zhu X, Zhangsun D, Yu J, Luo S. Loop2 Size Modification Reveals Significant Impacts on the Potency of α-Conotoxin TxID. Mar Drugs 2023; 21:md21050286. [PMID: 37233480 DOI: 10.3390/md21050286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 04/27/2023] [Accepted: 04/29/2023] [Indexed: 05/27/2023] Open
Abstract
α4/6-conotoxin TxID, which was identified from Conus textile, simultaneously blocks rat (r) α3β4 and rα6/α3β4 nicotinic acetylcholine receptors (nAChRs) with IC50 values of 3.6 nM and 33.9 nM, respectively. In order to identify the effects of loop2 size on the potency of TxID, alanine (Ala) insertion and truncation mutants were designed and synthesized in this study. An electrophysiological assay was used to evaluate the activity of TxID and its loop2-modified mutants. The results showed that the inhibition of 4/7-subfamily mutants [+9A]TxID, [+10A]TxID, [+14A]TxID, and all the 4/5-subfamily mutants against rα3β4 and rα6/α3β4 nAChRs decreased. Overall, ala-insertion or truncation of the 9th, 10th, and 11th amino acid results in a loss of inhibition and the truncation of loop2 has more obvious impacts on its functions. Our findings have strengthened the understanding of α-conotoxin, provided guidance for further modifications, and offered a perspective for future studies on the molecular mechanism of the interaction between α-conotoxins and nAChRs.
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Affiliation(s)
- Jianying Dong
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Panpan Zhang
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Junjie Xie
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Ting Xie
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Xiaopeng Zhu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Dongting Zhangsun
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China
| | - Jinpeng Yu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Sulan Luo
- School of Medicine, Guangxi University, Nanning 530004, China
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China
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Zhu X, Wang S, Kaas Q, Yu J, Wu Y, Harvey PJ, Zhangsun D, Craik DJ, Luo S. Discovery, Characterization, and Engineering of LvIC, an α4/4-Conotoxin That Selectively Blocks Rat α6/α3β4 Nicotinic Acetylcholine Receptors. J Med Chem 2023; 66:2020-2031. [PMID: 36682014 DOI: 10.1021/acs.jmedchem.2c01786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
α6β4 nicotinic acetylcholine receptors (nAChRs) are expressed in the central and peripheral nervous systems, but their functions are not fully understood, largely because of a lack of specific ligands. Here, we characterized a novel α-conotoxin, LvIC, and designed a series of analogues to probe structure-activity relationships at the α6β4 nAChR. The potency and selectivity of these conotoxins were tested using two-electrode voltage-clamp recording on nAChR subtypes expressed in Xenopus laevis oocytes. One of the analogues, [D1G,ΔQ14]LvIC, potently blocked α6/α3β4 nAChRs (α6/α3 is a chimera) with an IC50 of 19 nM, with minimal activity at other nAChR subtypes, including the structurally similar α6/α3β2β3 and α3β4 subtypes. Using NMR, molecular docking, and receptor mutation, structure-activity relationships of [D1G,ΔQ14]LvIC at the α6/α3β4 nAChR were defined. It is a potent and specific antagonist of α6β4 nAChRs that could potentially serve as a novel molecular probe to explore α6β4 nAChR-related neurophysiological and pharmacological functions.
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Affiliation(s)
- Xiaopeng Zhu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Shuai Wang
- Center for Novel Target and Therapeutic Intervention, Institute of Life Sciences, Chongqing Medical University, Chongqing 400016, China
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane 4072, Queensland, Australia
| | - Jinpeng Yu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Yong Wu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Peta J Harvey
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane 4072, Queensland, Australia
| | - Dongting Zhangsun
- School of Medicine, Guangxi University, Nanning 530004, China.,Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane 4072, Queensland, Australia
| | - Sulan Luo
- School of Medicine, Guangxi University, Nanning 530004, China.,Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
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Paguigan ND, Tun JO, Leavitt LS, Lin Z, Chase K, Dowell C, Deering-Rice CE, Lim AL, Karthikeyan M, Hughen RW, Zhang J, Peterson RT, Reilly CA, Light AR, Raghuraman S, McIntosh JM, Olivera BM, Schmidt EW. Nicotinic Acetylcholine Receptor Partial Antagonist Polyamides from Tunicates and Their Predatory Sea Slugs. ACS Chem Neurosci 2021; 12:2693-2704. [PMID: 34213884 DOI: 10.1021/acschemneuro.1c00345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In our efforts to discover new drugs to treat pain, we identified molleamines A-E (1-5) as major neuroactive components of the sea slug, Pleurobranchus forskalii, and their prey, Didemnum molle, tunicates. The chemical structures of molleamines were elucidated by spectroscopy and confirmed by the total synthesis of molleamines A (1) and C (3). Synthetic 3 completely blocked acetylcholine-induced calcium flux in peptidergic nociceptors (PNs) in the somatosensory nervous system. Compound 3 affected neither the α7 nAChR nor the muscarinic acetylcholine receptors in calcium flux assays. In addition to nociceptors, 3 partially blocked the acetylcholine-induced calcium flux in the sympathetic nervous system, including neurons from the superior cervical ganglion. Electrophysiology revealed a block of α3β4 (mouse) and α6/α3β4 (rat) nicotinic acetylcholine receptors (nAChRs), with IC50 values of 1.4 and 3.1 μM, respectively. Molleamine C (3) is a partial antagonist, reaching a maximum block of 76-82% of the acetylcholine signal and showing no partial agonist response. Molleamine C (3) may thus provide a lead compound for the development of neuroactive compounds with unique biological properties.
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Affiliation(s)
- Noemi D. Paguigan
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Jortan O. Tun
- School of Biological Sciences, University of Utah, Salt Lake City, Utah 84112, United States
| | - Lee S. Leavitt
- School of Biological Sciences, University of Utah, Salt Lake City, Utah 84112, United States
| | - Zhenjian Lin
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Kevin Chase
- School of Biological Sciences, University of Utah, Salt Lake City, Utah 84112, United States
| | - Cheryl Dowell
- School of Biological Sciences, University of Utah, Salt Lake City, Utah 84112, United States
| | - Cassandra E. Deering-Rice
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Albebson L. Lim
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Manju Karthikeyan
- School of Biological Sciences, University of Utah, Salt Lake City, Utah 84112, United States
| | - Ronald W. Hughen
- Department of Anesthesiology, School of Medicine, University of Utah, Salt Lake City, Utah 84112, United States
| | - Jie Zhang
- Department of Anesthesiology, School of Medicine, University of Utah, Salt Lake City, Utah 84112, United States
| | - Randall T. Peterson
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Christopher A. Reilly
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Alan R. Light
- Department of Anesthesiology, School of Medicine, University of Utah, Salt Lake City, Utah 84112, United States
| | - Shrinivasan Raghuraman
- School of Biological Sciences, University of Utah, Salt Lake City, Utah 84112, United States
| | - J. Michael McIntosh
- Department of Psychiatry, and School of Biological Sciences, University of Utah, Salt Lake City, Utah 84112, United States
- George E Whalen Veterans Affairs Medical Center, Salt Lake City, Utah 84148, United States
| | - Baldomero M. Olivera
- School of Biological Sciences, University of Utah, Salt Lake City, Utah 84112, United States
| | - Eric W. Schmidt
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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Nicotinic Acetylcholine Receptor Involvement in Inflammatory Bowel Disease and Interactions with Gut Microbiota. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18031189. [PMID: 33572734 PMCID: PMC7908252 DOI: 10.3390/ijerph18031189] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022]
Abstract
The gut-brain axis describes a complex interplay between the central nervous system and organs of the gastrointestinal tract. Sensory neurons of dorsal root and nodose ganglia, neurons of the autonomic nervous system, and immune cells collect and relay information about the status of the gut to the brain. A critical component in this bi-directional communication system is the vagus nerve which is essential for coordinating the immune system’s response to the activities of commensal bacteria in the gut and to pathogenic strains and their toxins. Local control of gut function is provided by networks of neurons in the enteric nervous system also called the ‘gut-brain’. One element common to all of these gut-brain systems is the expression of nicotinic acetylcholine receptors. These ligand-gated ion channels serve myriad roles in the gut-brain axis including mediating fast synaptic transmission between autonomic pre- and postganglionic neurons, modulation of neurotransmitter release from peripheral sensory and enteric neurons, and modulation of cytokine release from immune cells. Here we review the role of nicotinic receptors in the gut-brain axis with a focus on the interplay of these receptors with the gut microbiome and their involvement in dysregulation of gut function and inflammatory bowel diseases.
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Shreckengost J, Halder M, Mena-Avila E, Garcia-Ramirez DL, Quevedo J, Hochman S. Nicotinic receptor modulation of primary afferent excitability with selective regulation of Aδ-mediated spinal actions. J Neurophysiol 2020; 125:568-585. [PMID: 33326305 DOI: 10.1152/jn.00228.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Somatosensory input strength can be modulated by primary afferent depolarization (PAD) generated predominantly via presynaptic GABAA receptors on afferent terminals. We investigated whether ionotropic nicotinic acetylcholine receptors (nAChRs) also provide modulatory actions, focusing on myelinated afferent excitability in in vitro murine spinal cord nerve-attached models. Primary afferent stimulation-evoked synaptic transmission was recorded in the deep dorsal horn as extracellular field potentials (EFPs), whereas concurrently recorded dorsal root potentials (DRPs) were used as an indirect measure of PAD. Changes in afferent membrane excitability were simultaneously measured as direct current (DC)-shifts in membrane polarization recorded in dorsal roots or peripheral nerves. The broad nAChR antagonist d-tubocurarine (d-TC) selectively and strongly depressed Aδ-evoked synaptic EFPs (36% of control) coincident with similarly depressed A-fiber DRP (43% of control), whereas afferent electrical excitability remained unchanged. In comparison, acetylcholine (ACh) and the nAChR agonists, epibatidine and nicotine, reduced afferent excitability by generating coincident depolarizing DC-shifts in peripheral axons and intraspinally. Progressive depolarization corresponded temporally with the emergence of spontaneous axonal spiking and reductions in the DRP and all afferent-evoked synaptic actions (31%-37% of control). Loss of evoked response was long-lasting, independent of DC repolarization, and likely due to mechanisms initiated by spontaneous C-fiber activity. DC-shifts were blocked with d-TC but not GABAA receptor blockers and retained after tetrodotoxin block of voltage-gated Na+ channels. Notably, actions tested were comparable between three mouse strains, in rat, and when performed in different labs. Thus, nAChRs can regulate afferent excitability via two distinct mechanisms: by central Aδ-afferent actions, and by transient extrasynaptic axonal activation of high-threshold primary afferents.NEW & NOTEWORTHY Primary afferents express many nicotinic ACh receptor (nAChR) subtypes but whether activation is linked to presynaptic inhibition, facilitation, or more complex and selective activity modulation is unknown. Recordings of afferent-evoked responses in the lumbar spinal cord identified two nAChR-mediated modulatory actions: 1) selective control of Aδ afferent transmission and 2) robust changes in axonal excitability initiated via extrasynaptic shifts in DC polarization. This work broadens the diversity of presynaptic modulation of primary afferents by nAChRs.
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Affiliation(s)
| | - Mallika Halder
- Department of Physiology, Emory University, Atlanta, Georgia
| | - Elvia Mena-Avila
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - David Leonardo Garcia-Ramirez
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - Jorge Quevedo
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, México
| | - Shawn Hochman
- Department of Physiology, Emory University, Atlanta, Georgia
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Chronicling changes in the somatosensory neurons after peripheral nerve injury. Proc Natl Acad Sci U S A 2020; 117:26414-26421. [PMID: 33020310 DOI: 10.1073/pnas.1922618117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Current drug discovery efforts focus on identifying lead compounds acting on a molecular target associated with an established pathological state. Concerted molecular changes that occur in specific cell types during disease progression have generally not been identified. Here, we used constellation pharmacology to investigate rat dorsal root ganglion neurons using two models of peripheral nerve injury: chronic constriction injury (CCI) and spinal nerve ligation (SNL). In these well-established models of neuropathic pain, we show that the onset of chronic pain is accompanied by a dramatic, previously unreported increase in the number of bradykinin-responsive neurons, with larger increases observed after SNL relative to CCI. To define the neurons with altered expression, we charted the temporal course of molecular changes following 1, 3, 6, and 14 d after SNL injury and demonstrated that specific molecular changes have different time courses during the progression to a pain state. In particular, ATP receptors up-regulated on day 1 postinjury, whereas the increase in bradykinin receptors was gradual after day 3 postinjury. We specifically tracked changes in two subsets of neurons: peptidergic and nonpeptidergic nociceptors. Significant increases occurred in ATP responses in nAChR-expressing isolectin B4+ nonpeptidergic neurons 1 d postinjury, whereas peptidergic neurons did not display any significant change. We propose that remodeling of ion channels and receptors occurs in a concerted and cell-specific manner, resulting in the appearance of bradykinin-responsive neuronal subclasses that are relevant to chronic pain.
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Hone AJ, Rueda-Ruzafa L, Gordon TJ, Gajewiak J, Christensen S, Dyhring T, Albillos A, McIntosh JM. Expression of α3β2β4 nicotinic acetylcholine receptors by rat adrenal chromaffin cells determined using novel conopeptide antagonists. J Neurochem 2020; 154:158-176. [PMID: 31967330 DOI: 10.1111/jnc.14966] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/17/2019] [Accepted: 01/13/2020] [Indexed: 01/07/2023]
Abstract
Adrenal chromaffin cells release neurotransmitters in response to stress and may be involved in conditions such as post-traumatic stress and anxiety disorders. Neurotransmitter release is triggered, in part, by activation of nicotinic acetylcholine receptors (nAChRs). However, despite decades of use as a model system for studying exocytosis, the nAChR subtypes involved have not been pharmacologically identified. Quantitative real-time PCR of rat adrenal medulla revealed an abundance of mRNAs for α3, α7, β2, and β4 subunits. Whole-cell patch-clamp electrophysiology of chromaffin cells and subtype-selective ligands were used to probe for nAChRs derived from the mRNAs found in adrenal medulla. A novel conopeptide antagonist, PeIA-5469, was created that is highly selective for α3β2 over other nAChR subtypes heterologously expressed in Xenopus laevis oocytes. Experiments using PeIA-5469 and the α3β4-selective α-conotoxin TxID revealed that rat adrenal medulla contain two populations of chromaffin cells that express either α3β4 nAChRs alone or α3β4 together with the α3β2β4 subtype. Conclusions were derived from observations that acetylcholine-gated currents in some cells were sensitive to inhibition by PeIA-5469 and TxID, while in other cells, currents were sensitive only to TxID. Expression of functional α7 nAChRs was determined using three α7-selective ligands: the agonist PNU282987, the positive allosteric modulator PNU120596, and the antagonist α-conotoxin [V11L,V16D]ArIB. The results of these studies identify for the first time the expression of α3β2β4 nAChRs as well as functional α7 nAChRs by rat adrenal chromaffin cells.
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Affiliation(s)
- Arik J Hone
- George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah, USA.,School of Biological Sciences and University of Utah, Salt Lake City, Utah, USA.,Departament of Pharmacology and Therapeutics, Universidad Autónoma de Madrid, Madrid, Spain
| | - Lola Rueda-Ruzafa
- Departament of Pharmacology and Therapeutics, Universidad Autónoma de Madrid, Madrid, Spain.,Biomedical Research Center (CINBIO), University of Vigo, Vigo, Spain
| | - Thomas J Gordon
- School of Biological Sciences and University of Utah, Salt Lake City, Utah, USA
| | - Joanna Gajewiak
- School of Biological Sciences and University of Utah, Salt Lake City, Utah, USA
| | - Sean Christensen
- School of Biological Sciences and University of Utah, Salt Lake City, Utah, USA
| | | | - Almudena Albillos
- Departament of Pharmacology and Therapeutics, Universidad Autónoma de Madrid, Madrid, Spain
| | - J Michael McIntosh
- George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah, USA.,School of Biological Sciences and University of Utah, Salt Lake City, Utah, USA.,Department of Psychiatry, University of Utah, Salt Lake City, Utah, USA
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9
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Pastori V, D'Aloia A, Blasa S, Lecchi M. Serum-deprived differentiated neuroblastoma F-11 cells express functional dorsal root ganglion neuron properties. PeerJ 2019; 7:e7951. [PMID: 31687277 PMCID: PMC6825413 DOI: 10.7717/peerj.7951] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 09/25/2019] [Indexed: 11/29/2022] Open
Abstract
The isolation and culture of dorsal root ganglion (DRG) neurons cause adaptive changes in the expression and regulation of ion channels, with consequences on neuronal excitability. Considering that not all neurons survive the isolation and that DRG neurons are heterogeneous, it is difficult to find the cellular subtype of interest. For this reason, researchers opt for DRG-derived immortal cell lines to investigate endogenous properties. The F-11 cell line is a hybridoma of embryonic rat DRG neurons fused with the mouse neuroblastoma line N18TG2. In the proliferative condition, F-11 cells do not display a gene expression profile correspondent with specific subclasses of sensory neurons, but the most significant differences when compared with DRGs are the reduction of voltage-gated sodium, potassium and calcium channels, and the small amounts of TRPV1 transcripts. To investigate if functional properties of mature F-11 cells showed more similarities with those of isolated DRG neurons, we differentiated them by serum deprivation. Potassium and sodium currents significantly increased with differentiation, and biophysical properties of tetrodotoxin (TTX)-sensitive currents were similar to those characterized in small DRG neurons. The analysis of the voltage-dependence of calcium currents demonstrated the lack of low threshold activated components. The exclusive expression of high threshold activated Ca2+ currents and of TTX-sensitive Na+ currents correlated with the generation of a regular tonic electrical activity, which was recorded in the majority of the cells (80%) and was closely related to the activity of afferent TTX-sensitive A fibers of the proximal urethra and the bladder. Responses to capsaicin and substance P were also recorded in ~20% and ~80% of cells, respectively. The percentage of cells responsive to acetylcholine was consistent with the percentage referred for rat DRG primary neurons and cell electrical activity was modified by activation of non-NMDA receptors as for embryonic DRG neurons. These properties and the algesic profile (responses to pH5 and sensitivity to both ATP and capsaicin), proposed in literature to define a sub-classification of acutely dissociated rat DRG neurons, suggest that differentiated F-11 cells express receptors and ion channels that are also present in sensory neurons.
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Affiliation(s)
- Valentina Pastori
- Department of Biotechnology and Biosciences and Milan Center for Neuroscience, University of Milano-Bicocca, Milan, Italy
| | - Alessia D'Aloia
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Stefania Blasa
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Marzia Lecchi
- Department of Biotechnology and Biosciences and Milan Center for Neuroscience, University of Milano-Bicocca, Milan, Italy
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Broide RS, Winzer-Serhan UH, Chen Y, Leslie FM. Distribution of α7 Nicotinic Acetylcholine Receptor Subunit mRNA in the Developing Mouse. Front Neuroanat 2019; 13:76. [PMID: 31447654 PMCID: PMC6691102 DOI: 10.3389/fnana.2019.00076] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/12/2019] [Indexed: 01/10/2023] Open
Abstract
Homomeric α7 nicotinic acetylcholine receptors (nAChRs) are abundantly expressed in the central and peripheral nervous system (CNS and PNS, respectively), and spinal cord. In addition, expression and functional responses have been reported in non-neuronal tissue. In the nervous system, α7 nAChR subunit expression appears early during embryonic development and is often transiently upregulated, but little is known about their prenatal expression outside of the nervous system. For understanding potential short-term and long-term effects of gestational nicotine exposure, it is important to know the temporal and spatial expression of α7 nAChRs throughout the body. To that end, we studied the expression of α7 nAChR subunit mRNA using highly sensitive isotopic in situ hybridization in embryonic and neonatal whole-body mouse sections starting at gestational day 13. The results revealed expression of α7 mRNA as early as embryonic day 13 in the PNS, including dorsal root ganglia, parasympathetic and sympathetic ganglia, with the strongest expression in the superior cervical ganglion, and low to moderate levels were detected in brain and spinal cord, respectively, which rapidly increased in intensity with embryonic age. In addition, robust α7 mRNA expression was detected in the adrenal medulla, and low to moderate expression in selected peripheral tissues during embryonic development, potentially related to cells derived from the neural crest. Little or no mRNA expression was detected in thymus or spleen, sites of immune cell maturation. The results suggest that prenatal nicotine exposure could potentially affect the nervous system with limited effects in non-neural tissues.
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Affiliation(s)
- Ron S Broide
- Department of Pharmacology, University of California, Irvine, Irvine, CA, United States
| | - Ursula H Winzer-Serhan
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University College of Medicine, Bryan, TX, United States
| | - Yling Chen
- Department of Pharmacology, University of California, Irvine, Irvine, CA, United States
| | - Frances M Leslie
- Department of Pharmacology, University of California, Irvine, Irvine, CA, United States
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11
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Marine Toxins and Nociception: Potential Therapeutic Use in the Treatment of Visceral Pain Associated with Gastrointestinal Disorders. Toxins (Basel) 2019; 11:toxins11080449. [PMID: 31370176 PMCID: PMC6723473 DOI: 10.3390/toxins11080449] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 12/12/2022] Open
Abstract
Visceral pain, of which the pathogenic basis is currently largely unknown, is a hallmark symptom of both functional disorders, such as irritable bowel syndrome, and inflammatory bowel disease. Intrinsic sensory neurons in the enteric nervous system and afferent sensory neurons of the dorsal root ganglia, connecting with the central nervous system, represent the primary neuronal pathways transducing gut visceral pain. Current pharmacological therapies have several limitations, owing to their partial efficacy and the generation of severe adverse effects. Numerous cellular targets of visceral nociception have been recognized, including, among others, channels (i.e., voltage-gated sodium channels, VGSCs, voltage-gated calcium channels, VGCCs, Transient Receptor Potential, TRP, and Acid-sensing ion channels, ASICs) and neurotransmitter pathways (i.e., GABAergic pathways), which represent attractive targets for the discovery of novel drugs. Natural biologically active compounds, such as marine toxins, able to bind with high affinity and selectivity to different visceral pain molecular mediators, may represent a useful tool (1) to improve our knowledge of the physiological and pathological relevance of each nociceptive target, and (2) to discover therapeutically valuable molecules. In this review we report the most recent literature describing the effects of marine toxin on gastrointestinal visceral pain pathways and the possible clinical implications in the treatment of chronic pain associated with gut diseases.
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van Hout M, Valdes A, Christensen SB, Tran PT, Watkins M, Gajewiak J, Jensen AA, Olivera BM, McIntosh JM. α-Conotoxin VnIB from Conus ventricosus is a potent and selective antagonist of α6β4* nicotinic acetylcholine receptors. Neuropharmacology 2019; 157:107691. [PMID: 31255696 DOI: 10.1016/j.neuropharm.2019.107691] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/05/2019] [Accepted: 06/26/2019] [Indexed: 01/20/2023]
Abstract
α6-containing (α6*) nicotinic acetylcholine receptors (nAChRs) are expressed throughout the periphery and the central nervous system and constitute putative therapeutic targets in pain, addiction and movement disorders. The α6β2* nAChRs are relatively well studied, in part due to the availability of target specific α-conotoxins (α-Ctxs). In contrast, all native α-Ctxs identified that potently block α6β4 nAChRs exhibit higher potencies for the closely related α6β2β3 and/or α3β4 subtypes. In this study, we have identified a novel peptide from Conus ventricosus with pronounced selectivity for the α6β4 nAChR. The peptide-encoding gene was cloned from genomic DNA and the predicted mature peptide, α-Ctx VnIB, was synthesized. The functional properties of VnIB were characterized at rat and human nAChRs expressed in Xenopus oocytes by two-electrode voltage clamp electrophysiology. VnIB potently inhibited ACh-evoked currents at rα6β4 and rα6/α3β4 nAChRs, displayed ∼20-fold and ∼250-fold lower potencies at rα3β4 and rα6/α3β2β3 receptors, respectively, and exhibited negligible effects at eight other nAChR subtypes. Interestingly, even higher degrees of selectivity were observed for hα6/α3β4 over hα6/α3β2β3 and hα3β4 receptors. Finally, VnIB displayed fast binding kinetics at rα6/α3β4 (on-rate t½ = 0.87 min-1, off-rate t½ = 2.7 min-1). The overall preference of VnIB for β4* over β2* nAChRs is similar to the selectivity profiles of other 4/6 α-Ctxs. However, in contrast to previously identified native α-Ctxs targeting α6* nAChRs, VnIB displays pronounced selectivity for α6β4 nAChRs over both α3β4 and α6β2β3 receptors. VnIB thus represents a novel molecular probe for elucidating the physiological role and therapeutic properties of α6β4* nAChRs.
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Affiliation(s)
- Marloes van Hout
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Amanda Valdes
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Sean B Christensen
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA.
| | - Phuong T Tran
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Maren Watkins
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA; Department of Pathology, University of Utah, Salt Lake City, UT, 84112, USA.
| | - Joanna Gajewiak
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA.
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | | | - J Michael McIntosh
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA; Department of Psychiatry, University of Utah, Salt Lake City, UT, 84108, USA; George E. Wahlen Veterans Affair Medical Center, Salt Lake City, UT, 84148, USA.
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Zhang X, Hartung JE, Friedman RL, Koerber HR, Belfer I, Gold MS. Nicotine Evoked Currents in Human Primary Sensory Neurons. THE JOURNAL OF PAIN 2019; 20:810-818. [PMID: 30659887 DOI: 10.1016/j.jpain.2019.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/18/2018] [Accepted: 01/03/2019] [Indexed: 11/28/2022]
Abstract
Sensory neuron nicotinic acetylcholine receptors (nAChRs) contribute to pain associated with tissue injury. However, there are marked differences between rats and mice with respect to both the properties and distribution of nAChR currents in sensory neurons. Because both species are used to understand pain signaling in humans, we sought to determine whether the currents present in either species was reflective of those present in human sensory neurons. Neurons from the L4/L5 dorsal root ganglia were obtained from adult male and female organ donors. Nicotine evoked currents were detected in 40 of 47 neurons (85%). In contrast with the naïve mouse, in which almost all nAChR currents are transient, or the rat, in which both mouse-like transient and more slowly activating and inactivating currents are detected, all the currents in human DRG neurons were slow, but slower than those in the rat. Currents were blocked by the nAChR antagonists mecamylamine (30 µmol/L), but not by the TRPA1 selective antagonist HC-030031 (10 µmol/L). Single cell polymerase chain reaction analysis of nicotinic receptor subunit expression in human DRG neurons are consistent with functional data indicating that receptor expression is detected 85 ± 2.1% of neurons assessed (n = 48, from 4 donors). The most prevalent coexpression pattern was α3/β2 (95 ± 4% of neurons with subunits), but α7 subunits were detected in 70 ± 3.4% of neurons. These results suggest that there are not only species differences in the sensory neuron distribution of nAChR currents between rodent and human, but that the subunit composition of the channel underlying human nAChR currents may be different from those in the mouse or rat. PERSPECTIVE: The properties and distribution of nicotine evoked currents in human sensory neurons were markedly different from those previously observed in mice and rats. These observations add additional support to the suggestion that human sensory neurons may be an essential screening tool for those considering moving novel therapeutics targeting primary afferents into clinical trials.
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Affiliation(s)
| | - Jane E Hartung
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Robert L Friedman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - H Richard Koerber
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | | | - Michael S Gold
- Department of Anesthesiology; Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
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Conotoxin κM-RIIIJ, a tool targeting asymmetric heteromeric K v1 channels. Proc Natl Acad Sci U S A 2018; 116:1059-1064. [PMID: 30593566 DOI: 10.1073/pnas.1813161116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The vast complexity of native heteromeric K+ channels is largely unexplored. Defining the composition and subunit arrangement of individual subunits in native heteromeric K+ channels and establishing their physiological roles is experimentally challenging. Here we systematically explored this "zone of ignorance" in molecular neuroscience. Venom components, such as peptide toxins, appear to have evolved to modulate physiologically relevant targets by discriminating among closely related native ion channel complexes. We provide proof-of-principle for this assertion by demonstrating that κM-conotoxin RIIIJ (κM-RIIIJ) from Conus radiatus precisely targets "asymmetric" Kv channels composed of three Kv1.2 subunits and one Kv1.1 or Kv1.6 subunit with 100-fold higher apparent affinity compared with homomeric Kv1.2 channels. Our study shows that dorsal root ganglion (DRG) neurons contain at least two major functional Kv1.2 channel complexes: a heteromer, for which κM-RIIIJ has high affinity, and a putative Kv1.2 homomer, toward which κM-RIIIJ is less potent. This conclusion was reached by (i) covalent linkage of members of the mammalian Shaker-related Kv1 family to Kv1.2 and systematic assessment of the potency of κM-RIIIJ block of heteromeric K+ channel-mediated currents in heterologous expression systems; (ii) molecular dynamics simulations of asymmetric Kv1 channels providing insights into the molecular basis of κM-RIIIJ selectivity and potency toward its targets; and (iii) evaluation of calcium responses of a defined population of DRG neurons to κM-RIIIJ. Our study demonstrates that bioactive molecules present in venoms provide essential pharmacological tools that systematically target specific heteromeric Kv channel complexes that operate in native tissues.
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Athie MCP, Vieira AS, Teixeira JM, dos Santos GG, Dias EV, Tambeli CH, Sartori CR, Parada CA. Transcriptome analysis of dorsal root ganglia's diabetic neuropathy reveals mechanisms involved in pain and regeneration. Life Sci 2018; 205:54-62. [DOI: 10.1016/j.lfs.2018.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/26/2018] [Accepted: 05/06/2018] [Indexed: 11/15/2022]
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Nishizawa Y, Takahashi K, Oguma N, Tominaga M, Ohta T. Possible involvement of transient receptor potential ankyrin 1 in Ca2+
signaling via T-type Ca2+
channel in mouse sensory neurons. J Neurosci Res 2017; 96:901-910. [DOI: 10.1002/jnr.24208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 11/06/2017] [Accepted: 11/27/2017] [Indexed: 01/30/2023]
Affiliation(s)
- Yuki Nishizawa
- Department of Veterinary Pharmacology, Faculty of Agriculture; Tottori University; Tottori Japan
| | - Kenji Takahashi
- Department of Veterinary Pharmacology, Faculty of Agriculture; Tottori University; Tottori Japan
| | - Naoko Oguma
- Department of Veterinary Pharmacology, Faculty of Agriculture; Tottori University; Tottori Japan
| | - Makoto Tominaga
- Division of Cell Signaling; Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences; Okazaki Japan
| | - Toshio Ohta
- Department of Veterinary Pharmacology, Faculty of Agriculture; Tottori University; Tottori Japan
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Albillos A, McIntosh JM. Human nicotinic receptors in chromaffin cells: characterization and pharmacology. Pflugers Arch 2017; 470:21-27. [PMID: 29058146 DOI: 10.1007/s00424-017-2073-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/14/2017] [Accepted: 09/19/2017] [Indexed: 02/03/2023]
Abstract
During the last 10 years, we have been working on human chromaffin cells obtained from the adrenal gland of organ donors that suffered encephalic or cardiac death. We first electrophysiologically characterized the nicotinic acetylcholine receptors (nAChRs) activated by acetylcholine, and their contribution to the exocytosis of chromaffin vesicles and release of catecholamines. We have shown that these cells possess an adrenergic phenotype. This phenotype may contribute to an increased expression of α7 nAChRs in these cells, allowing for recording of α7 nAChR currents, something that had previously not been achieved in non-human species. The use of α-conotoxins allowed us to characterize non-α7 nAChR subtypes and, together with molecular biology experiments, conclude that the predominant nAChR subtype in human chromaffin cells is α3β4* (asterisk indicates the posible presence of additional subunits). In addition, there is a minor population of αxβ2 nAChRs. Both α7 and non-α7 nAChR subtypes contribute to the exocytotic process. Exocytosis mediated by nAChRs could be as large in magnitude as that elicited by calcium entry through voltage-dependent calcium channels. Finally, we have also investigated the effect of nAChR-targeted tobacco cessation drugs on catecholamine release in chromaffin cells. We have concluded that at therapeutic concentrations, varenicline alone does not increase the frequency of action potentials evoked by ACh. However, varenicline in the presence of nicotine does increase this frequency, and thus, in the presence of both drugs, the probability of increased catecholamine release in human chromaffin cells is high.
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Affiliation(s)
- Almudena Albillos
- Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Calle Arzobispo Morcillo 4, 28029, Madrid, Spain.
| | - J Michael McIntosh
- George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT, USA.,Department of Biology, University of Utah, Salt Lake City, UT, USA.,Department of Psychiatry, University of Utah, Salt Lake City, UT, USA
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18
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Hone AJ, Servent D, McIntosh JM. α9-containing nicotinic acetylcholine receptors and the modulation of pain. Br J Pharmacol 2017; 175:1915-1927. [PMID: 28662295 DOI: 10.1111/bph.13931] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/09/2017] [Accepted: 06/13/2017] [Indexed: 01/01/2023] Open
Abstract
Neuropathic pain is a complex and debilitating syndrome for which there are few effective pharmacological treatments. Opioid-based medications are initially effective for acute pain, but tolerance to their analgesic effects quickly develops, and long-term use often leads to physical dependence and addiction. Furthermore, neuropathic pain is generally resistant to non-steroidal anti-inflammatory drugs. Other classes of medications including antidepressants, antiepileptics and voltage-gated calcium channel inhibitors are only partially effective in most patients, may be associated with significant side effects and have few disease-modifying effects on the underlying pathology. Medications that act through new mechanisms of action, and particularly ones that have disease-modifying properties, would be highly desirable. In the last decade, a potential new target for the treatment of neuropathic pain has emerged: the α9-containing nicotinic acetylcholine receptor (nAChR). Recent studies indicate that antagonists of α9-containing nAChRs are analgesic in animal models of neuropathic pain. These nerve injury models include chronic constriction injury, partial sciatic nerve ligation, streptozotocin-induced diabetic neuropathy and chemotherapeutic-induced neuropathy. This review details the history and state of the field regarding the role that α9-containing nAChRs may play in neuropathic pain. An alternative hypothesis that α-conotoxins exert their therapeutic effect through blocking N-type calcium channels via activation of GABAB receptors is also reviewed. Understanding how antagonists of α9-containing nAChRs exert their therapeutic effects may ultimately result in the development of medications that not only treat but also prevent the development of neuropathic pain states. LINKED ARTICLES This article is part of a themed section on Nicotinic Acetylcholine Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.11/issuetoc.
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Affiliation(s)
- Arik J Hone
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| | - Denis Servent
- Service d'Ingénierie Moléculaire des Protéines (SIMOPRO), IBITECS, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - J Michael McIntosh
- Department of Biology, University of Utah, Salt Lake City, UT, USA.,George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT, USA.,Department of Psychiatry, University of Utah, Salt Lake City, UT, USA
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19
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Dutertre S, Nicke A, Tsetlin VI. Nicotinic acetylcholine receptor inhibitors derived from snake and snail venoms. Neuropharmacology 2017. [PMID: 28623170 DOI: 10.1016/j.neuropharm.2017.06.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nicotinic acetylcholine receptor (nAChR) represents the prototype of ligand-gated ion channels. It is vital for neuromuscular transmission and an important regulator of neurotransmission. A variety of toxic compounds derived from diverse species target this receptor and have been of elemental importance in basic and applied research. They enabled milestone discoveries in pharmacology and biochemistry ranging from the original formulation of the receptor concept, the first isolation and structural analysis of a receptor protein (the nAChR) to the identification, localization, and differentiation of its diverse subtypes and their validation as a target for therapeutic intervention. Among the venom-derived compounds, α-neurotoxins and α-conotoxins provide the largest families and still represent indispensable pharmacological tools. Application of modified α-neurotoxins provided substantial structural and functional details of the nAChR long before high resolution structures were available. α-bungarotoxin represents not only a standard pharmacological tool and label in nAChR research but also for unrelated proteins tagged with a minimal α-bungarotoxin binding motif. A major advantage of α-conotoxins is their smaller size, as well as superior selectivity for diverse nAChR subtypes that allows their development into ligands with optimized pharmacological and chemical properties and potentially novel drugs. In the following, these two groups of nAChR antagonists will be described focusing on their respective roles in the structural and functional characterization of nAChRs and their development into research tools. In addition, we provide a comparative overview of the diverse α-conotoxin selectivities that can serve as a practical guide for both structure activity studies and subtype classification. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Sébastien Dutertre
- Institut des Biomolécules Max Mousseron, UMR 5247, Université Montpellier - CNRS, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Annette Nicke
- Walther Straub Institute for Pharmacology and Toxicology, Ludwig-Maximilians-Universität, Nußbaumstr. 26, 80336 Munich, Germany.
| | - Victor I Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str.16/10, Moscow 117999, Russian Federation
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20
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Cuny H, Yu R, Tae HS, Kompella SN, Adams DJ. α-Conotoxins active at α3-containing nicotinic acetylcholine receptors and their molecular determinants for selective inhibition. Br J Pharmacol 2017; 175:1855-1868. [PMID: 28477355 DOI: 10.1111/bph.13852] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 04/13/2017] [Accepted: 04/24/2017] [Indexed: 01/22/2023] Open
Abstract
Neuronal α3-containing nicotinic acetylcholine receptors (nAChRs) in the peripheral nervous system (PNS) and non-neuronal tissues are implicated in a number of severe disease conditions ranging from cancer to cardiovascular diseases and chronic pain. However, despite the physiological characterization of mouse models and cell lines, the precise pathophysiology of nAChRs outside the CNS remains not well understood, in part because there is a lack of subtype-selective antagonists. α-Conotoxins isolated from cone snail venom exhibit characteristic individual selectivity profiles for nAChRs and, therefore, are excellent tools to study the determinants for nAChR-antagonist interactions. Given that human α3β4 subtype selective α-conotoxins are scarce and this is a major nAChR subtype in the PNS, the design of new peptides targeting this nAChR subtype is desirable. Recent studies using α-conotoxins RegIIA and AuIB, in combination with nAChR site-directed mutagenesis and computational modelling, have shed light onto specific nAChR residues, which determine the selectivity of the α-conotoxins for the human α3β2 and α3β4 subtypes. Publications describing the selectivity profile and binding sites of other α-conotoxins confirm that subtype-selective nAChR antagonists often work through common mechanisms by interacting with the same structural components and sites on the receptor. LINKED ARTICLES This article is part of a themed section on Nicotinic Acetylcholine Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.11/issuetoc.
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Affiliation(s)
- Hartmut Cuny
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia.,Victor Chang Cardiac Research Institute, Developmental and Stem Cell Biology Division, Sydney, NSW, Australia
| | - Rilei Yu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China.,Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Han-Shen Tae
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
| | - Shiva N Kompella
- Faculty of Pharmacy, University of Sydney, Sydney, NSW, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
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Shelukhina I, Mikhailov N, Abushik P, Nurullin L, Nikolsky EE, Giniatullin R. Cholinergic Nociceptive Mechanisms in Rat Meninges and Trigeminal Ganglia: Potential Implications for Migraine Pain. Front Neurol 2017; 8:163. [PMID: 28496430 PMCID: PMC5406407 DOI: 10.3389/fneur.2017.00163] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/07/2017] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Parasympathetic innervation of meninges and ability of carbachol, acetylcholine (ACh) receptor (AChR) agonist, to induce headaches suggests contribution of cholinergic mechanisms to primary headaches. However, neurochemical mechanisms of cholinergic regulation of peripheral nociception in meninges, origin place for headache, are almost unknown. METHODS Using electrophysiology, calcium imaging, immunohistochemistry, and staining of meningeal mast cells, we studied effects of cholinergic agents on peripheral nociception in rat hemiskulls and isolated trigeminal neurons. RESULTS Both ACh and carbachol significantly increased nociceptive firing in peripheral terminals of meningeal trigeminal nerves recorded by local suction electrode. Strong nociceptive firing was also induced by nicotine, implying essential role of nicotinic AChRs in control of excitability of trigeminal nerve endings. Nociceptive firing induced by carbachol was reduced by muscarinic antagonist atropine, whereas the action of nicotine was prevented by the nicotinic blocker d-tubocurarine but was insensitive to the TRPA1 antagonist HC-300033. Carbachol but not nicotine induced massive degranulation of meningeal mast cells known to release multiple pro-nociceptive mediators. Enzymes terminating ACh action, acetylcholinesterase (AChE) and butyrylcholinesterase, were revealed in perivascular meningeal nerves. The inhibitor of AChE neostigmine did not change the firing per se but induced nociceptive activity, sensitive to d-tubocurarine, after pretreatment of meninges with the migraine mediator CGRP. This observation suggested the pro-nociceptive action of endogenous ACh in meninges. Both nicotine and carbachol induced intracellular Ca2+ transients in trigeminal neurons partially overlapping with expression of capsaicin-sensitive TRPV1 receptors. CONCLUSION Trigeminal nerve terminals in meninges, as well as dural mast cells and trigeminal ganglion neurons express a repertoire of pro-nociceptive nicotinic and muscarinic AChRs, which could be activated by the ACh released from parasympathetic nerves. These receptors represent a potential target for novel therapeutic interventions in trigeminal pain and probably in migraine.
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Affiliation(s)
- Irina Shelukhina
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.,Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Nikita Mikhailov
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Polina Abushik
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Leniz Nurullin
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Kazan, Russian Federation.,Open Laboratory of Neuropharmacology, Kazan Federal University, Kazan, Russian Federation
| | - Evgeny E Nikolsky
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Kazan, Russian Federation.,Open Laboratory of Neuropharmacology, Kazan Federal University, Kazan, Russian Federation
| | - Rashid Giniatullin
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.,Laboratory of Neurobiology, Kazan Federal University, Kazan, Russian Federation
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22
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Memon T, Chase K, Leavitt LS, Olivera BM, Teichert RW. TRPA1 expression levels and excitability brake by K V channels influence cold sensitivity of TRPA1-expressing neurons. Neuroscience 2017; 353:76-86. [PMID: 28408328 DOI: 10.1016/j.neuroscience.2017.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/30/2017] [Accepted: 04/01/2017] [Indexed: 12/30/2022]
Abstract
The molecular sensor of innocuous (painless) cold sensation is well-established to be transient receptor potential cation channel, subfamily M, member 8 (TRPM8). However, the role of transient receptor potential cation channel, subfamily A, member 1 (TRPA1) in noxious (painful) cold sensation has been controversial. We find that TRPA1 channels contribute to the noxious cold sensitivity of mouse somatosensory neurons, independent of TRPM8 channels, and that TRPA1-expressing neurons are largely non-overlapping with TRPM8-expressing neurons in mouse dorsal-root ganglia (DRG). However, relatively few TRPA1-expressing neurons (e.g., responsive to allyl isothiocyanate or AITC, a selective TRPA1 agonist) respond overtly to cold temperature in vitro, unlike TRPM8-expressing neurons, which almost all respond to cold. Using somatosensory neurons from TRPM8-/- mice and subtype-selective blockers of TRPM8 and TRPA1 channels, we demonstrate that responses to cold temperatures from TRPA1-expressing neurons are mediated by TRPA1 channels. We also identify two factors that affect the cold-sensitivity of TRPA1-expressing neurons: (1) cold-sensitive AITC-sensitive neurons express relatively more TRPA1 transcripts than cold-insensitive AITC-sensitive neurons and (2) voltage-gated potassium (KV) channels attenuate the cold-sensitivity of some TRPA1-expressing neurons. The combination of these two factors, combined with the relatively weak agonist-like activity of cold temperature on TRPA1 channels, partially explains why few TRPA1-expressing neurons respond to cold. Blocking KV channels also reveals another subclass of noxious cold-sensitive DRG neurons that do not express TRPM8 or TRPA1 channels. Altogether, the results of this study provide novel insights into the cold-sensitivity of different subclasses of somatosensory neurons.
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Affiliation(s)
- Tosifa Memon
- Department of Biology, University of Utah, 257 S. 1400 E., Salt Lake City, UT 84112, United States
| | - Kevin Chase
- Department of Biology, University of Utah, 257 S. 1400 E., Salt Lake City, UT 84112, United States
| | - Lee S Leavitt
- Department of Biology, University of Utah, 257 S. 1400 E., Salt Lake City, UT 84112, United States
| | - Baldomero M Olivera
- Department of Biology, University of Utah, 257 S. 1400 E., Salt Lake City, UT 84112, United States
| | - Russell W Teichert
- Department of Biology, University of Utah, 257 S. 1400 E., Salt Lake City, UT 84112, United States.
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Espino SS, Dilanyan T, Imperial JS, Aguilar MB, Teichert RW, Bandyopadhyay P, Olivera BM. Glycine-rich conotoxins from the Virgiconus clade. Toxicon 2016; 113:11-7. [PMID: 26851775 DOI: 10.1016/j.toxicon.2016.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/23/2016] [Accepted: 02/02/2016] [Indexed: 01/24/2023]
Abstract
Cone snails in the Virgiconus clade prey on marine worms. Here, we identify six related conotoxins in the O1-superfamily from three species in this clade, Conus virgo, Conus terebra and Conus kintoki. One of these peptides, vi6a, was directly purified from the venom of C. virgo by following its activity using calcium imaging of dissociated mouse dorsal root ganglion (DRG) neurons. The purified peptide was biochemically characterized, synthesized and tested for activity in mice. Hyperactivity was observed upon both intraperitoneal and intracranial injection of the peptide. The effect of the synthetic peptide on DRG neurons was identical to that of the native peptide. Using the vi6a sequence, five other homologs were identified. These peptides define a glycine-rich subgroup of the O1-superfamily from the Virgiconus clade, with biological activity in mice.
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Affiliation(s)
- Samuel S Espino
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake, UT 84112, USA
| | - Taleen Dilanyan
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake, UT 84112, USA; Department of Chemistry, Smith College, Northampton, MA 01063, USA
| | - Julita S Imperial
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake, UT 84112, USA.
| | - Manuel B Aguilar
- Laboratorio de Neurofarmacología Marina, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, México
| | - Russell W Teichert
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake, UT 84112, USA
| | - Pradip Bandyopadhyay
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake, UT 84112, USA
| | - Baldomero M Olivera
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake, UT 84112, USA
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Curtice KJ, Leavitt LS, Chase K, Raghuraman S, Horvath MP, Olivera BM, Teichert RW. Classifying neuronal subclasses of the cerebellum through constellation pharmacology. J Neurophysiol 2015; 115:1031-42. [PMID: 26581874 DOI: 10.1152/jn.00894.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 11/12/2015] [Indexed: 11/22/2022] Open
Abstract
A pressing need in neurobiology is the comprehensive identification and characterization of neuronal subclasses within the mammalian nervous system. To this end, we used constellation pharmacology as a method to interrogate the neuronal and glial subclasses of the mouse cerebellum individually and simultaneously. We then evaluated the data obtained from constellation-pharmacology experiments by cluster analysis to classify cells into neuronal and glial subclasses, based on their functional expression of glutamate, acetylcholine, and GABA receptors, among other ion channels. Conantokin peptides were used to identify N-methyl-d-aspartate (NMDA) receptor subtypes, which revealed that neurons of the young mouse cerebellum expressed NR2A and NR2B NMDA receptor subunits. Additional pharmacological tools disclosed differential expression of α-amino-3-hydroxy-5-methyl-4-isoxazloepropionic, nicotinic acetylcholine, and muscarinic acetylcholine receptors in different neuronal and glial subclasses. Certain cell subclasses correlated with known attributes of granule cells, and we combined constellation pharmacology with genetically labeled neurons to identify and characterize Purkinje cells. This study illustrates the utility of applying constellation pharmacology to classify neuronal and glial subclasses in specific anatomical regions of the brain.
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Affiliation(s)
- Kigen J Curtice
- Department of Biology, University of Utah, Salt Lake City, Utah
| | - Lee S Leavitt
- Department of Biology, University of Utah, Salt Lake City, Utah
| | - Kevin Chase
- Department of Biology, University of Utah, Salt Lake City, Utah
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Teichert RW, Schmidt EW, Olivera BM. Constellation pharmacology: a new paradigm for drug discovery. Annu Rev Pharmacol Toxicol 2015; 55:573-89. [PMID: 25562646 DOI: 10.1146/annurev-pharmtox-010814-124551] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Constellation pharmacology is a cell-based high-content phenotypic-screening platform that utilizes subtype-selective pharmacological agents to elucidate the cell-specific combinations (constellations) of key signaling proteins that define specific cell types. Heterogeneous populations of native cells, in which the different individual cell types have been identified and characterized, are the foundation for this screening platform. Constellation pharmacology is useful for screening small molecules or for deconvoluting complex mixtures of biologically active natural products. This platform has been used to purify natural products and discover their molecular mechanisms. In the ongoing development of constellation pharmacology, there is a positive feedback loop between the pharmacological characterization of cell types and screening for new drug candidates. As constellation pharmacology is used to discover compounds with novel targeting-selectivity profiles, those new compounds then further help to elucidate the constellations of specific cell types, thereby increasing the content of this high-content platform.
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Hone AJ, McIntosh JM, Azam L, Lindstrom J, Lucero L, Whiteaker P, Passas J, Blázquez J, Albillos A. α-Conotoxins Identify the α3β4* Subtype as the Predominant Nicotinic Acetylcholine Receptor Expressed in Human Adrenal Chromaffin Cells. Mol Pharmacol 2015; 88:881-93. [PMID: 26330550 DOI: 10.1124/mol.115.100982] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 08/31/2015] [Indexed: 01/17/2023] Open
Abstract
Ligands that selectively inhibit human α3β2 and α6β2 nicotinic acetylcholine receptor (nAChRs) and not the closely related α3β4 and α6β4 subtypes are lacking. Current α-conotoxins (α-Ctxs) that discriminate among these nAChR subtypes in rat fail to discriminate among the human receptor homologs. In this study, we describe the development of α-Ctx LvIA(N9R,V10A) that is 3000-fold more potent on oocyte-expressed human α3β2 than α3β4 and 165-fold more potent on human α6/α3β2β3 than α6/α3β4 nAChRs. This analog was used in conjuction with three other α-Ctx analogs and patch-clamp electrophysiology to characterize the nAChR subtypes expressed by human adrenal chromaffin cells. LvIA(N9R,V10A) showed little effect on the acetylcholine-evoked currents in these cells at concentrations expected to inhibit nAChRs with β2 ligand-binding sites. In contrast, the β4-selective α-Ctx BuIA(T5A,P6O) inhibited >98% of the acetylcholine-evoked current, indicating that most of the heteromeric receptors contained β4 ligand-binding sites. Additional studies using the α6-selective α-Ctx PeIA(A7V,S9H,V10A,N11R,E14A) indicated that the predominant heteromeric nAChR expressed by human adrenal chromaffin cells is the α3β4* subtype (asterisk indicates the possible presence of additional subunits). This conclusion was supported by polymerase chain reaction experiments of human adrenal medulla gland and of cultured human adrenal chromaffin cells that demonstrated prominent expression of RNAs for α3, α5, α7, β2, and β4 subunits and a low abundance of RNAs for α2, α4, α6, and α10 subunits.
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Affiliation(s)
- Arik J Hone
- Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain (A.J.H., A.A.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M., L.A.); George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.); Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania (J.L.); Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona (L.L., P.W.); Hospital Doce de Octubre, Madrid, Spain (J.P.); and Hospital Clínico San Carlos Madrid, Spain (J.B.)
| | - J Michael McIntosh
- Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain (A.J.H., A.A.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M., L.A.); George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.); Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania (J.L.); Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona (L.L., P.W.); Hospital Doce de Octubre, Madrid, Spain (J.P.); and Hospital Clínico San Carlos Madrid, Spain (J.B.)
| | - Layla Azam
- Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain (A.J.H., A.A.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M., L.A.); George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.); Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania (J.L.); Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona (L.L., P.W.); Hospital Doce de Octubre, Madrid, Spain (J.P.); and Hospital Clínico San Carlos Madrid, Spain (J.B.)
| | - Jon Lindstrom
- Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain (A.J.H., A.A.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M., L.A.); George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.); Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania (J.L.); Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona (L.L., P.W.); Hospital Doce de Octubre, Madrid, Spain (J.P.); and Hospital Clínico San Carlos Madrid, Spain (J.B.)
| | - Linda Lucero
- Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain (A.J.H., A.A.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M., L.A.); George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.); Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania (J.L.); Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona (L.L., P.W.); Hospital Doce de Octubre, Madrid, Spain (J.P.); and Hospital Clínico San Carlos Madrid, Spain (J.B.)
| | - Paul Whiteaker
- Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain (A.J.H., A.A.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M., L.A.); George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.); Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania (J.L.); Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona (L.L., P.W.); Hospital Doce de Octubre, Madrid, Spain (J.P.); and Hospital Clínico San Carlos Madrid, Spain (J.B.)
| | - Juan Passas
- Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain (A.J.H., A.A.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M., L.A.); George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.); Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania (J.L.); Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona (L.L., P.W.); Hospital Doce de Octubre, Madrid, Spain (J.P.); and Hospital Clínico San Carlos Madrid, Spain (J.B.)
| | - Jesús Blázquez
- Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain (A.J.H., A.A.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M., L.A.); George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.); Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania (J.L.); Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona (L.L., P.W.); Hospital Doce de Octubre, Madrid, Spain (J.P.); and Hospital Clínico San Carlos Madrid, Spain (J.B.)
| | - Almudena Albillos
- Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain (A.J.H., A.A.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M., L.A.); George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.); Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, Pennsylvania (J.L.); Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona (L.L., P.W.); Hospital Doce de Octubre, Madrid, Spain (J.P.); and Hospital Clínico San Carlos Madrid, Spain (J.B.)
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Insights into the origins of fish hunting in venomous cone snails from studies of Conus tessulatus. Proc Natl Acad Sci U S A 2015; 112:5087-92. [PMID: 25848010 DOI: 10.1073/pnas.1424435112] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Prey shifts in carnivorous predators are events that can initiate the accelerated generation of new biodiversity. However, it is seldom possible to reconstruct how the change in prey preference occurred. Here we describe an evolutionary "smoking gun" that illuminates the transition from worm hunting to fish hunting among marine cone snails, resulting in the adaptive radiation of fish-hunting lineages comprising ∼100 piscivorous Conus species. This smoking gun is δ-conotoxin TsVIA, a peptide from the venom of Conus tessulatus that delays inactivation of vertebrate voltage-gated sodium channels. C. tessulatus is a species in a worm-hunting clade, which is phylogenetically closely related to the fish-hunting cone snail specialists. The discovery of a δ-conotoxin that potently acts on vertebrate sodium channels in the venom of a worm-hunting cone snail suggests that a closely related ancestral toxin enabled the transition from worm hunting to fish hunting, as δ-conotoxins are highly conserved among fish hunters and critical to their mechanism of prey capture; this peptide, δ-conotoxin TsVIA, has striking sequence similarity to these δ-conotoxins from piscivorous cone snail venoms. Calcium-imaging studies on dissociated dorsal root ganglion (DRG) neurons revealed the peptide's putative molecular target (voltage-gated sodium channels) and mechanism of action (inhibition of channel inactivation). The results were confirmed by electrophysiology. This work demonstrates how elucidating the specific interactions between toxins and receptors from phylogenetically well-defined lineages can uncover molecular mechanisms that underlie significant evolutionary transitions.
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Imperial JS, Cabang AB, Song J, Raghuraman S, Gajewiak J, Watkins M, Showers-Corneli P, Fedosov A, Concepcion GP, Terlau H, Teichert RW, Olivera BM. A family of excitatory peptide toxins from venomous crassispirine snails: using Constellation Pharmacology to assess bioactivity. Toxicon 2014; 89:45-54. [PMID: 24997406 DOI: 10.1016/j.toxicon.2014.06.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 06/10/2014] [Accepted: 06/12/2014] [Indexed: 11/19/2022]
Abstract
The toxinology of the crassispirine snails, a major group of venomous marine gastropods within the superfamily Conoidea, is largely unknown. Here we define the first venom peptide superfamily, the P-like crassipeptides, and show that the organization of their gene sequences is similar to conotoxin precursors. We provide evidence that one peptide family within the P-like crassipeptide superfamily includes potassium-channel (K-channel) blockers, the κP-crassipeptides. Three of these peptides were chemically synthesized (cce9a, cce9b and iqi9a). Using conventional electrophysiology, cce9b was shown to be an antagonist of both a human Kv1.1 channel isoform (Shaker subfamily of voltage-gated K channels) and a Drosophila K-channel isoform. We assessed the bioactivity of these peptides in native mammalian dorsal root ganglion neurons in culture. We demonstrate that two of these crassipeptides, cce9a and cce9b, elicited an excitatory phenotype in a subset of small-diameter capsaicin-sensitive mouse DRG neurons that were also affected by κJ-conotoxin PlXIVA (pl14a), a blocker of Kv1.6 channels. Given the vast complexity of heteromeric K-channel isoforms, this study demonstrates that the crassispirine venoms are a potentially rich source for discovering novel peptides that can help to identify and characterize the diversity of K-channel subtypes expressed in native neurons and other cell types.
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Affiliation(s)
- Julita S Imperial
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA.
| | - April B Cabang
- Marine Science Institute, University of the Philippines, Diliman, Quezon City 1101, Philippines
| | - Jie Song
- Institute of Physiology, University of Kiel, Hermann-Rodewald-Straße 5, 24118 Kiel, Germany
| | - Shrinivasan Raghuraman
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA
| | - Joanna Gajewiak
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA
| | - Maren Watkins
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA
| | - Patrice Showers-Corneli
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA
| | - Alexander Fedosov
- A.N. Severtzov Institute of Ecology and Evolution, Russian Academy of Science, Moscow, 119071 Russia
| | - Gisela P Concepcion
- Marine Science Institute, University of the Philippines, Diliman, Quezon City 1101, Philippines
| | - Heinrich Terlau
- Institute of Physiology, University of Kiel, Hermann-Rodewald-Straße 5, 24118 Kiel, Germany
| | - Russell W Teichert
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA
| | - Baldomero M Olivera
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA
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Defining modulatory inputs into CNS neuronal subclasses by functional pharmacological profiling. Proc Natl Acad Sci U S A 2014; 111:6449-54. [PMID: 24733934 DOI: 10.1073/pnas.1404421111] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Previously we defined neuronal subclasses within the mouse peripheral nervous system using an experimental strategy called "constellation pharmacology." Here we demonstrate the broad applicability of constellation pharmacology by extending it to the CNS and specifically to the ventral respiratory column (VRC) of mouse brainstem, a region containing the neuronal network controlling respiratory rhythm. Analysis of dissociated cells from this locus revealed three major cell classes, each encompassing multiple subclasses. We broadly analyzed the combinations (constellations) of receptors and ion channels expressed within VRC cell classes and subclasses. These were strikingly different from the constellations of receptors and ion channels found in subclasses of peripheral neurons from mouse dorsal root ganglia. Within the VRC cell population, a subset of dissociated neurons responded to substance P, putatively corresponding to inspiratory pre-Bötzinger complex (preBötC) neurons. Using constellation pharmacology, we found that these substance P-responsive neurons also responded to histamine, and about half responded to bradykinin. Electrophysiological studies conducted in brainstem slices confirmed that preBötC neurons responsive to substance P exhibited similar responsiveness to bradykinin and histamine. The results demonstrate the predictive utility of constellation pharmacology for defining modulatory inputs into specific neuronal subclasses within central neuronal networks.
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Using constellation pharmacology to define comprehensively a somatosensory neuronal subclass. Proc Natl Acad Sci U S A 2014; 111:2319-24. [PMID: 24469798 DOI: 10.1073/pnas.1324019111] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Change is intrinsic to nervous systems; change is required for learning and conditioning and occurs with disease progression, normal development, and aging. To better understand mammalian nervous systems and effectively treat nervous-system disorders, it is essential to track changes in relevant individual neurons. A critical challenge is to identify and characterize the specific cell types involved and the molecular-level changes that occur in each. Using an experimental strategy called constellation pharmacology, we demonstrate that we can define a specific somatosensory neuronal subclass, cold thermosensors, across different species and track changes in these neurons as a function of development. Cold thermosensors are uniformly responsive to menthol and innocuous cool temperature (17 °C), indicating that they express TRPM8 channels. A subset of cold thermosensors expressed α7 nicotinic acetylcholine receptors (nAChRs) but not other nAChR subtypes. Differences in temperature threshold of cold thermosensors correlated with functional expression of voltage-gated K channels Kv1.1/1.2: Relatively higher expression of KV1.1/1.2 channels resulted in a higher threshold response to cold temperature. Other signaling components varied during development and between species. In cold thermosensors of neonatal mice and rats, ATP receptors were functionally expressed, but the expression disappeared with development. This developmental change occurred earlier in low-threshold than high-threshold cold thermosensors. Most rat cold thermosensors expressed TRPA1 channels, whereas mouse cold thermosensors did not. The broad implications of this study are that it is now feasible to track changes in receptor and ion-channel expression in individual neuronal subclasses as a function of development, learning, disease, or aging.
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