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Wang Y, Huang R, Chai Z, Wang C, Du X, Hang Y, Xu Y, Li J, Jiang X, Wu X, Qiao Z, Li Y, Liu B, Zhang X, Cao P, Zhu F, Zhou Z. Ca 2+ -independent transmission at the central synapse formed between dorsal root ganglion and dorsal horn neurons. EMBO Rep 2022; 23:e54507. [PMID: 36148511 PMCID: PMC9638852 DOI: 10.15252/embr.202154507] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 08/07/2022] [Accepted: 08/30/2022] [Indexed: 09/25/2023] Open
Abstract
A central principle of synaptic transmission is that action potential-induced presynaptic neurotransmitter release occurs exclusively via Ca2+ -dependent secretion (CDS). The discovery and mechanistic investigations of Ca2+ -independent but voltage-dependent secretion (CiVDS) have demonstrated that the action potential per se is sufficient to trigger neurotransmission in the somata of primary sensory and sympathetic neurons in mammals. One key question remains, however, whether CiVDS contributes to central synaptic transmission. Here, we report, in the central transmission from presynaptic (dorsal root ganglion) to postsynaptic (spinal dorsal horn) neurons in vitro, (i) excitatory postsynaptic currents (EPSCs) are mediated by glutamate transmission through both CiVDS (up to 87%) and CDS; (ii) CiVDS-mediated EPSCs are independent of extracellular and intracellular Ca2+ ; (iii) CiVDS is faster than CDS in vesicle recycling with much less short-term depression; (iv) the fusion machinery of CiVDS includes Cav2.2 (voltage sensor) and SNARE (fusion pore). Together, an essential component of activity-induced EPSCs is mediated by CiVDS in a central synapse.
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Affiliation(s)
- Yuan Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Rong Huang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Zuying Chai
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Changhe Wang
- Department of NeurologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'anChina
- Neuroscience Research Center, Institute of Mitochondrial Biology and Medicine, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and TechnologyXi'an Jiaotong UniversityXi'anChina
| | - Xingyu Du
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Yuqi Hang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Yongxin Xu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Jie Li
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Xiaohan Jiang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Xi Wu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Zhongjun Qiao
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Yinglin Li
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Bing Liu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | | | - Peng Cao
- National Institute of Biological SciencesBeijingChina
| | - Feipeng Zhu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Zhuan Zhou
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
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Ramiro IBL, Bjørn-Yoshimoto WE, Imperial JS, Gajewiak J, Salcedo PF, Watkins M, Taylor D, Resager W, Ueberheide B, Bräuner-Osborne H, Whitby FG, Hill CP, Martin LF, Patwardhan A, Concepcion GP, Olivera BM, Safavi-Hemami H. Somatostatin venom analogs evolved by fish-hunting cone snails: From prey capture behavior to identifying drug leads. SCIENCE ADVANCES 2022; 8:eabk1410. [PMID: 35319982 PMCID: PMC8942377 DOI: 10.1126/sciadv.abk1410] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
Somatostatin (SS) is a peptide hormone with diverse physiological roles. By investigating a deep-water clade of fish-hunting cone snails, we show that predator-prey evolution has generated a diverse set of SS analogs, each optimized to elicit specific systemic physiological effects in prey. The increased metabolic stability, distinct SS receptor activation profiles, and chemical diversity of the venom analogs make them suitable leads for therapeutic application, including pain, cancer, and endocrine disorders. Our findings not only establish the existence of SS-like peptides in animal venoms but also serve as a model for the synergy gained from combining molecular phylogenetics and behavioral observations to optimize the discovery of natural products with biomedical potential.
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Affiliation(s)
- Iris Bea L. Ramiro
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen-N 2200, Denmark
- The Marine Science Institute, University of the Philippines, Quezon City 1101, Philippines
| | | | - Julita S. Imperial
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Joanna Gajewiak
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Paula Flórez Salcedo
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112, USA
| | - Maren Watkins
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Dylan Taylor
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - William Resager
- New York University Langone Medical Center, New York, NY 10016, USA
| | | | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen-Ø 2100, Denmark
| | - Frank G. Whitby
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Christopher P. Hill
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Laurent F. Martin
- Department of Anesthesiology and Pharmacology, University of Arizona, Tucson, AZ 85724, USA
| | - Amol Patwardhan
- Department of Anesthesiology and Pharmacology, University of Arizona, Tucson, AZ 85724, USA
| | - Gisela P. Concepcion
- The Marine Science Institute, University of the Philippines, Quezon City 1101, Philippines
| | - Baldomero M. Olivera
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Helena Safavi-Hemami
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen-N 2200, Denmark
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84112, USA
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Hasan MM, Starobova H, Mueller A, Vetter I, Lewis RJ. Subcutaneous ω-Conotoxins Alleviate Mechanical Pain in Rodent Models of Acute Peripheral Neuropathy. Mar Drugs 2021; 19:106. [PMID: 33670311 PMCID: PMC7917901 DOI: 10.3390/md19020106] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 11/16/2022] Open
Abstract
The peripheral effects of ω-conotoxins, selective blockers of N-type voltage-gated calcium channels (CaV2.2), have not been characterised across different clinically relevant pain models. This study examines the effects of locally administered ω-conotoxin MVIIA, GVIA, and CVIF on mechanical and thermal paw withdrawal threshold (PWT) in postsurgical pain (PSP), cisplatin-induced neuropathy (CisIPN), and oxaliplatin-induced neuropathy (OIPN) rodent models. Intraplantar injection of 300, 100 and 30 nM MVIIA significantly (p < 0.0001, p < 0.0001, and p < 0.05, respectively) alleviated mechanical allodynia of mice in PSP model compared to vehicle control group. Similarly, intraplantar injection of 300, 100, and 30 nM MVIIA (p < 0.0001, p < 0.01, and p < 0.05, respectively), and 300 nM and 100 nM GVIA (p < 0.0001 and p < 0.05, respectively) significantly increased mechanical thresholds of mice in OIPN model. The ED50 of GVIA and MVIIA in OIPN was found to be 1.8 pmol/paw and 0.8 pmol/paw, respectively. However, none of the ω-conotoxins were effective in a mouse model of CisIPN. The intraplantar administration of 300 nM GVIA, MVIIA, and CVIF did not cause any locomotor side effects. The intraplantar administration of MVIIA can alleviate incision-induced mechanical allodynia, and GVIA and MVIIA effectively reduce OIPN associated mechanical pain, without locomotor side effects, in rodent models. In contrast, CVIF was inactive in these pain models, suggesting it is unable to block a subset of N-type voltage-gated calcium channels associated with nociceptors in the skin.
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Affiliation(s)
- Md. Mahadhi Hasan
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (M.M.H.); (H.S.); (A.M.); (I.V.)
| | - Hana Starobova
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (M.M.H.); (H.S.); (A.M.); (I.V.)
| | - Alexander Mueller
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (M.M.H.); (H.S.); (A.M.); (I.V.)
| | - Irina Vetter
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (M.M.H.); (H.S.); (A.M.); (I.V.)
- School of Pharmacy, The University of Queensland, Brisbane, QLD 4102, Australia
| | - Richard J. Lewis
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (M.M.H.); (H.S.); (A.M.); (I.V.)
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Mellott A, Rockwood J, Zhelay T, Luu CT, Kaitsuka T, Kozak JA. TRPM7 channel activity in Jurkat T lymphocytes during magnesium depletion and loading: implications for divalent metal entry and cytotoxicity. Pflugers Arch 2020; 472:1589-1606. [PMID: 32964285 DOI: 10.1007/s00424-020-02457-3] [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] [Received: 05/15/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 12/14/2022]
Abstract
TRPM7 is a cation channel-protein kinase highly expressed in T lymphocytes and other immune cells. It has been proposed to constitute a cellular entry pathway for Mg2+ and divalent metal cations such as Ca2+, Zn2+, Cd2+, Mn2+, and Ni2+. TRPM7 channels are inhibited by cytosolic Mg2+, rendering them largely inactive in intact cells. The dependence of channel activity on extracellular Mg2+ is less well studied. Here, we measured native TRPM7 channel activity in Jurkat T cells maintained in external Mg2+ concentrations varying between 400 nM and 1.4 mM for 1-3 days, obtaining an IC50 value of 54 μM. Maintaining the cells in 400 nM or 8 μM [Mg2+]o resulted in almost complete activation of TRPM7 in intact cells, due to cytosolic Mg2+ depletion. A total of 1.4 mM [Mg2+]o was sufficient to fully eliminate the basal current. Submillimolar concentrations of amiloride prevented cellular Mg2+ depletion but not loading. We investigated whether the cytotoxicity of TRPM7 permeant metal ions Ni2+, Zn2+, Cd2+, Co2+, Mn2+, Sr2+, and Ba2+ requires TRPM7 channel activity. Mg2+ loading modestly reduced cytotoxicity of Zn2+, Co2+, Ni2+, and Mn2+ but not of Cd2+. Channel blocker NS8593 reduced Co2+ and Mn2+ but not Cd2+ or Zn2+ cytotoxicity and interfered with Mg2+ loading as evaluated by TRPM7 channel basal activity. Ba2+ and Sr2+ were neither detectably toxic nor permeant through the plasma membrane. These results indicate that in Jurkat T cells, entry of toxic divalent metal cations primarily occurs through pathways distinct from TRPM7. By contrast, we found evidence that Mg2+ entry requires TRPM7 channels.
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Affiliation(s)
- Alayna Mellott
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, 45435, USA
| | - Jananie Rockwood
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, 45435, USA
| | - Tetyana Zhelay
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, 45435, USA
| | - Charles Tuan Luu
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, 45435, USA
| | - Taku Kaitsuka
- School of Pharmacy in Fukuoka, International University of Health and Welfare, Enokizu 137-1, Okawa, Fukuoka, Japan
| | - J Ashot Kozak
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, OH, 45435, USA.
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Moya‐Díaz J, Bayonés L, Montenegro M, Cárdenas AM, Koch H, Doi A, Marengo FD. Ca 2+ -independent and voltage-dependent exocytosis in mouse chromaffin cells. Acta Physiol (Oxf) 2020; 228:e13417. [PMID: 31769918 DOI: 10.1111/apha.13417] [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] [Received: 03/13/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 12/11/2022]
Abstract
AIM It is widely accepted that the exocytosis of synaptic and secretory vesicles is triggered by Ca2+ entry through voltage-dependent Ca2+ channels. However, there is evidence of an alternative mode of exocytosis induced by membrane depolarization but lacking Ca2+ current and intracellular Ca2+ increase. In this work we investigated if such a mechanism contributes to secretory vesicle exocytosis in mouse chromaffin cells. METHODS Exocytosis was evaluated by patch-clamp membrane capacitance measurements, carbon fibre amperometry and TIRF. Cytosolic Ca2+ was estimated using epifluorescence microscopy and fluo-8 (salt form). RESULTS Cells stimulated by brief depolatizations in absence of extracellular Ca+2 show moderate but consistent exocytosis, even in presence of high cytosolic BAPTA concentration and pharmacological inhibition of Ca+2 release from intracellular stores. This exocytosis is tightly dependent on membrane potential, is inhibited by neurotoxin Bont-B (cleaves the v-SNARE synaptobrevin), is very fast (saturates with time constant <10 ms), it is followed by a fast endocytosis sensitive to the application of an anti-dynamin monoclonal antibody, and recovers after depletion in <5 s. Finally, this exocytosis was inhibited by: (i) ω-agatoxin IVA (blocks P/Q-type Ca2+ channel gating), (ii) in cells from knock-out P/Q-type Ca2+ channel mice, and (iii) transfection of free synprint peptide (interferes in P/Q channel-exocytic proteins association). CONCLUSION We demonstrated that Ca2+ -independent and voltage-dependent exocytosis is present in chromaffin cells. This process is tightly coupled to membrane depolarization, and is able to support secretion during action potentials at low basal rates. P/Q-type Ca2+ channels can operate as voltage sensors of this process.
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Affiliation(s)
- José Moya‐Díaz
- Instituto de Fisiología, Biología Molecular y Neurociencias Departamento de Fisiología y Biología Molecular y Celular Facultad de Ciencias Exactas y Naturales Universidad de Buenos AiresConsejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
| | - Lucas Bayonés
- Instituto de Fisiología, Biología Molecular y Neurociencias Departamento de Fisiología y Biología Molecular y Celular Facultad de Ciencias Exactas y Naturales Universidad de Buenos AiresConsejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
| | - Mauricio Montenegro
- Instituto de Fisiología, Biología Molecular y Neurociencias Departamento de Fisiología y Biología Molecular y Celular Facultad de Ciencias Exactas y Naturales Universidad de Buenos AiresConsejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
| | - Ana M. Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso Facultad de Ciencias Universidad de Valparaíso Valparaíso Chile
| | - Henner Koch
- Center for Integrative Brain Research Seattle Children's Research Institute Seattle WA USA
- Department of Neurology and Epileptology Hertie‐Institute for Clinical Brain ResearchUniversity of Tübingen Tübingen Germany
| | - Atsushi Doi
- Department of Rehabilitation Graduate School of Health Science Kumamoto Health Science University Kumamoto Japan
| | - Fernando D. Marengo
- Instituto de Fisiología, Biología Molecular y Neurociencias Departamento de Fisiología y Biología Molecular y Celular Facultad de Ciencias Exactas y Naturales Universidad de Buenos AiresConsejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
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Ca 2+-independent but voltage-dependent quantal catecholamine secretion (CiVDS) in the mammalian sympathetic nervous system. Proc Natl Acad Sci U S A 2019; 116:20201-20209. [PMID: 31530723 DOI: 10.1073/pnas.1902444116] [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] [Indexed: 01/09/2023] Open
Abstract
Action potential-induced vesicular exocytosis is considered exclusively Ca2+ dependent in Katz's Ca2+ hypothesis on synaptic transmission. This long-standing concept gets an exception following the discovery of Ca2+-independent but voltage-dependent secretion (CiVDS) and its molecular mechanisms in dorsal root ganglion sensory neurons. However, whether CiVDS presents only in sensory cells remains elusive. Here, by combining multiple independent recordings, we report that [1] CiVDS robustly presents in the sympathetic nervous system, including sympathetic superior cervical ganglion neurons and slice adrenal chromaffin cells, [2] uses voltage sensors of Ca2+ channels (N-type and novel L-type), and [3] contributes to catecholamine release in both homeostatic and fight-or-flight like states; [4] CiVDS-mediated catecholamine release is faster than that of Ca2+-dependent secretion at the quantal level and [5] increases Ca2+ currents and contractility of cardiac myocytes. Together, CiVDS presents in the sympathetic nervous system with potential physiological functions, including cardiac muscle contractility.
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Chai Z, Wang C, Huang R, Wang Y, Zhang X, Wu Q, Wang Y, Wu X, Zheng L, Zhang C, Guo W, Xiong W, Ding J, Zhu F, Zhou Z. Ca V2.2 Gates Calcium-Independent but Voltage-Dependent Secretion in Mammalian Sensory Neurons. Neuron 2017; 96:1317-1326.e4. [PMID: 29198756 DOI: 10.1016/j.neuron.2017.10.028] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 09/15/2017] [Accepted: 10/24/2017] [Indexed: 01/13/2023]
Abstract
Action potential induces membrane depolarization and triggers intracellular free Ca2+ concentration (Ca2+)-dependent secretion (CDS) via Ca2+ influx through voltage-gated Ca2+ channels. We report a new type of somatic exocytosis triggered by the action potential per se-Ca2+-independent but voltage-dependent secretion (CiVDS)-in dorsal root ganglion neurons. Here we uncovered the molecular mechanism of CiVDS, comprising a voltage sensor, fusion machinery, and their linker. Specifically, the voltage-gated N-type Ca2+ channel (CaV2.2) is the voltage sensor triggering CiVDS, the SNARE complex functions as the vesicle fusion machinery, the "synprint" of CaV2.2 serves as a linker between the voltage sensor and the fusion machinery, and ATP is a cargo of CiVDS vesicles. Thus, CiVDS releases ATP from the soma while CDS releases glutamate from presynaptic terminals, establishing the CaV2.2-SNARE "voltage-gating fusion pore" as a novel pathway co-existing with the canonical "Ca2+-gating fusion pore" pathway for neurotransmitter release following action potentials in primary sensory neurons.
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Affiliation(s)
- Zuying Chai
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Changhe Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China; Center for Mitochondrial Biology and Medicine, Key Laboratory of Biomedical Information Engineering of The Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Rong Huang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Yuan Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Xiaoyu Zhang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China; School of Stomatology, Peking University, Beijing 100871, China
| | - Qihui Wu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Yeshi Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Xi Wu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Lianghong Zheng
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Chen Zhang
- College of Life Sciences, Peking University, Beijing 100871, China
| | - Wei Guo
- THU IDG/McGovern Institute, Tsinghua University, Beijing 100084, China
| | - Wei Xiong
- THU IDG/McGovern Institute, Tsinghua University, Beijing 100084, China
| | - Jiuping Ding
- Institute of Biophysics and Biochemistry, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Feipeng Zhu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Zhuan Zhou
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China.
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8
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Li CL, Liu XF, Li GX, Ban MQ, Chen JZ, Cui Y, Zhang JH, Wu CF. Antinociceptive Effects of AGAP, a Recombinant Neurotoxic Polypeptide: Possible Involvement of the Tetrodotoxin-Resistant Sodium Channels in Small Dorsal Root Ganglia Neurons. Front Pharmacol 2016; 7:496. [PMID: 28066245 PMCID: PMC5168466 DOI: 10.3389/fphar.2016.00496] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 12/02/2016] [Indexed: 11/22/2022] Open
Abstract
Antitumor-analgesic peptide (AGAP) is a novel recombinant polypeptide. The primary study showed that AGAP 1.0 mg/kg exhibited strong analgesic and antitumor effects. The tail vein administration of AGAP potently reduced pain behaviors in mice induced by intraplantar injection of formalin or intraperitoneal injection of acetic acid, without affecting basal pain perception. To further assess the mechanisms of AGAP, the effects of AGAP on sodium channels were assessed using the whole-cell patch clamp recordings in dorsal root ganglia (DRG) neurons. The results showed that AGAP (3–1000 nM) inhibited the sodium currents in small-diameter DRG neurons in a dose-dependent manner. 1000 nM AGAP could inhibit the current density-voltage relationship curve of sodium channels in a voltage-dependent manner and negatively shift the activation curves. 1000 nM AGAP could reduce the tetrodotoxin-resistant (TTX-R) sodium currents by 42.8% in small-diameter DRG neurons. Further analysis revealed that AGAP potently inhibited NaV1.8 currents by 59.4%, and negatively shifted the activation and inactivation kinetics. 1000 nM AGAP also reduced the NaV1.9 currents by 33.7%, but had no significant effect on activation and inactivation kinetics. Thus, our results demonstrated that submicromolar concentrations of AGAP inhibited TTX-R sodium channel in rat small-diameter DRG neurons. It is concluded that these new results may better explain, at least in part, the analgesic properties of this polypeptide.
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Affiliation(s)
- Chun-Li Li
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
| | - Xi-Fang Liu
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
| | - Gui-Xia Li
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
| | - Meng-Qi Ban
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
| | - Jian-Zhao Chen
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
| | - Yong Cui
- Department of Biochemistry, Shenyang Pharmaceutical University Shenyang, China
| | - Jing-Hai Zhang
- Department of Biochemistry, Shenyang Pharmaceutical University Shenyang, China
| | - Chun-Fu Wu
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
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9
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Kalia J, Milescu M, Salvatierra J, Wagner J, Klint JK, King GF, Olivera BM, Bosmans F. From foe to friend: using animal toxins to investigate ion channel function. J Mol Biol 2014; 427:158-175. [PMID: 25088688 DOI: 10.1016/j.jmb.2014.07.027] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/18/2014] [Accepted: 07/18/2014] [Indexed: 12/19/2022]
Abstract
Ion channels are vital contributors to cellular communication in a wide range of organisms, a distinct feature that renders this ubiquitous family of membrane-spanning proteins a prime target for toxins found in animal venom. For many years, the unique properties of these naturally occurring molecules have enabled researchers to probe the structural and functional features of ion channels and to define their physiological roles in normal and diseased tissues. To illustrate their considerable impact on the ion channel field, this review will highlight fundamental insights into toxin-channel interactions and recently developed toxin screening methods and practical applications of engineered toxins.
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Affiliation(s)
- Jeet Kalia
- Indian Institute of Science Education and Research Pune; Pune, Maharashtra 411 008 India
| | - Mirela Milescu
- Division of Biological Sciences; University of Missouri, Columbia, MO 65211 USA
| | - Juan Salvatierra
- Department of Physiology; Johns Hopkins University, School of Medicine, Baltimore, MD 21205 USA
| | - Jordan Wagner
- Department of Physiology; Johns Hopkins University, School of Medicine, Baltimore, MD 21205 USA
| | - Julie K Klint
- Institute for Molecular Bioscience; The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Glenn F King
- Institute for Molecular Bioscience; The University of Queensland, St. Lucia, QLD 4072 Australia
| | | | - Frank Bosmans
- Department of Physiology; Johns Hopkins University, School of Medicine, Baltimore, MD 21205 USA.,Solomon H. Snyder Department of Neuroscience; Johns Hopkins University, School of Medicine, Baltimore, MD 21205 USA
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10
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Icilin reduces voltage-gated calcium channel currents in naïve and injured DRG neurons in the rat spinal nerve ligation model. Brain Res 2014; 1557:171-9. [PMID: 24560602 DOI: 10.1016/j.brainres.2014.02.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 02/07/2014] [Accepted: 02/11/2014] [Indexed: 11/21/2022]
Abstract
Recently, the transient receptor potential (TRP) channels TRPM8 and TRPA1 have been identified as molecular sensors for cold, and it has been suggested that they play a crucial role in allodynia by modulating voltage-gated calcium channel currents (ICa(V)). The aim of this study was to analyze the modulation of ICa(V) by the TRPM8-agonist icilin in vitro and to investigate the analgesic effect of icilin in a neuropathic pain model in vivo. Whole cell patch-clamp recordings were performed on isolated naïve and injured rat dorsal root ganglia (DRG) neurons, and the analgesic efficacy of icilin applied topically to the paws or intrathecally was tested in rats after spinal nerve ligation (SNL). ICa(V) (depolarization from -80 to 0mV) in naïve DRG neurons was reduced dose dependently (0.002-200µM) by icilin (18-80%). Subtype isolation of calcium channels show a marked reduction of L-type channel currents compared to N-type channel currents. The effects of icilin on ICa(V) were not significantly different in non-injured and SNL-injured DRG neurons. In vivo, neither topical (10-200µM) nor intrathecal application of icilin (0.1nM to 1µM) affected tactile allodynia or thermal hyperalgesia after SNL, but it increases cold allodynia 6h after application. We conclude that the icilin-induced modulation of ICa(V) in DRG neurons is unlikely to mediate analgesic effects or contribute directly to the pathogenesis of cold allodynia in the rat SNL model, but it is a potential mechanism for the analgesic effects of icilin in other pain models.
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11
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Hannon HE, Atchison WD. Omega-conotoxins as experimental tools and therapeutics in pain management. Mar Drugs 2013; 11:680-99. [PMID: 23470283 PMCID: PMC3705365 DOI: 10.3390/md11030680] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/14/2013] [Accepted: 02/15/2013] [Indexed: 12/24/2022] Open
Abstract
Neuropathic pain afflicts a large percentage of the global population. This form of chronic, intractable pain arises when the peripheral or central nervous systems are damaged, either directly by lesion or indirectly through disease. The comorbidity of neuropathic pain with other diseases, including diabetes, cancer, and AIDS, contributes to a complex pathogenesis and symptom profile. Because most patients present with neuropathic pain refractory to current first-line therapeutics, pharmaceuticals with greater efficacy in pain management are highly desired. In this review we discuss the growing application of ω-conotoxins, small peptides isolated from Conus species, in the management of neuropathic pain. These toxins are synthesized by predatory cone snails as a component of paralytic venoms. The potency and selectivity with which ω-conotoxins inhibit their molecular targets, voltage-gated Ca2+ channels, is advantageous in the treatment of neuropathic pain states, in which Ca2+ channel activity is characteristically aberrant. Although ω-conotoxins demonstrate analgesic efficacy in animal models of neuropathic pain and in human clinical trials, there remains a critical need to improve the convenience of peptide drug delivery methods, and reduce the number and severity of adverse effects associated with ω-conotoxin-based therapies.
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Affiliation(s)
- Heidi E Hannon
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824, USA.
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12
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Adams DJ, Callaghan B, Berecki G. Analgesic conotoxins: block and G protein-coupled receptor modulation of N-type (Ca(V) 2.2) calcium channels. Br J Pharmacol 2012; 166:486-500. [PMID: 22091786 DOI: 10.1111/j.1476-5381.2011.01781.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Conotoxins (conopeptides) are small disulfide bonded peptides from the venom of marine cone snails. These peptides target a wide variety of membrane receptors, ion channels and transporters, and have enormous potential for a range of pharmaceutical applications. Structurally related ω-conotoxins bind directly to and selectively inhibit neuronal (N)-type voltage-gated calcium channels (VGCCs) of nociceptive primary afferent neurones. Among these, ω-conotoxin MVIIA (Prialt) is approved by the Food and Drug Administration (FDA) as an alternative intrathecal analgesic for the management of chronic intractable pain, particularly in patients refractory to opioids. A series of newly discovered ω-conotoxins from Conus catus, including CVID-F, are potent and selective antagonists of N-type VGCCs. In spinal cord slices, these peptides reversibly inhibit excitatory synaptic transmission between primary afferents and dorsal horn superficial lamina neurones, and in the rat partial sciatic nerve ligation model of neuropathic pain, significantly reduce allodynic behaviour. Another family of conotoxins, the α-conotoxins, are competitive antagonists of mammalian nicotinic acetylcholine receptors (nAChRs). α-Conotoxins Vc1.1 and RgIA possess two disulfide bonds and are currently in development as a treatment for neuropathic pain. It was initially proposed that the primary target of these peptides is the α9α10 neuronal nAChR. Surprisingly, however, α-conotoxins Vc1.1, RgIA and PeIA more potently inhibit N-type VGCC currents via a GABA(B) GPCR mechanism in rat sensory neurones. This inhibition is largely voltage-independent and involves complex intracellular signalling. Understanding the molecular mechanisms of conotoxin action will lead to new ways to regulate VGCC block and modulation in normal and diseased states of the nervous system.
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Affiliation(s)
- David J Adams
- Health Innovations Research Institute, RMIT University, Melbourne, Victoria, Australia.
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13
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Gowd KH, Blais KD, Elmslie KS, Steiner AM, Olivera BM, Bulaj G. Dissecting a role of evolutionary-conserved but noncritical disulfide bridges in cysteine-rich peptides using ω-conotoxin GVIA and its selenocysteine analogs. Biopolymers 2012; 98:212-23. [PMID: 22782563 DOI: 10.1002/bip.22047] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Conotoxins comprise a large group of peptidic neurotoxins that use diverse disulfide-rich scaffolds. Each scaffold is determined by an evolutionarily conserved pattern of cysteine residues. Although many structure-activity relationship studies confirm the functional and structural importance of disulfide crosslinks, there is growing evidence that not all disulfide bridges are critical in maintaining activities of conotoxins. To answer the fundamental biological question of what the role of noncritical disulfide bridges is, we investigated function and folding of disulfide-depleted analogs of ω-conotoxin GVIA (GVIA) that belongs to an inhibitory cystine knot motif family and blocks N-type calcium channels. Removal of a noncritical Cys1-Cys16 disulfide bridge in GVIA or its selenopeptide analog had, as predicted, rather minimal effects on the inhibitory activity on calcium channels, as well as on in vivo activity following intracranial administration. However, the disulfide-depleted GVIA exhibited significantly lower folding yields for forming the remaining two native disulfide bridges. The disulfide-depleted selenoconotoxin GVIA analog also folded with significantly lower yields, suggesting that the functionally noncritical disulfide pair plays an important cooperative role in forming the native disulfide scaffold. Taken together, our results suggest that distinct disulfide bridges may be evolutionarily preserved by the oxidative folding or/and stabilization of the bioactive conformation of a disulfide-rich scaffold.
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14
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Lin ZY, Chen LM, Zhang J, Pan XD, Zhu YG, Ye QY, Huang HP, Chen XC. Ginsenoside Rb1 selectively inhibits the activity of L-type voltage-gated calcium channels in cultured rat hippocampal neurons. Acta Pharmacol Sin 2012; 33:438-44. [PMID: 22407229 DOI: 10.1038/aps.2011.181] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
AIM To investigate the effect of ginsenoside Rb1 on voltage-gated calcium currents in cultured rat hippocampal neurons and the modulatory mechanism. METHODS Cultured hippocampal neurons were prepared from Sprague Dawley rat embryos. Whole-cell configuration of the patch-clamp technique was used to record the voltage-gated calcium currents (VGCCs) from the hippocampal neurons,and the effect of Rb1 was examined. RESULTS Rb1 (2-100 μmol/L) inhibited VGCCs in a concentration-dependent manner, and the current was mostly recovered upon wash-out. The specific L-type Ca(2+) channel inhibitor nifedipine (10 μmol/L) occluded Rb1-induced inhibition on VGCCs. Neither the selective N-type Ca(2+) channel blocker ω-conotoxin-GVIA (1 μmol/L), nor the selective P/Q-type Ca(2+) channel blocker ω-agatoxin IVA (30 nmol/L) diminished Rb1-sensitive VGCCs. Rb1 induced a leftward shift of the steady-state inactivation curve of I(Ca) to a negative potential without affecting its activation kinetics or reversal potential in the I-V curve. The inhibitory effect of Rb1 was neither abolished by the adenylyl cyclase activator forskolin (10 μmol/L), nor by the PKA inhibitor H-89 (10 μmol/L). CONCLUSION Ginsenoside Rb1 selectively inhibits the activity of L-type voltage-gated calcium channels, without affecting the N-type or P/Q-type Ca(2+) channels in hippocampal neurons. cAMP-PKA signaling pathway is not involved in this effect.
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Abstract
Voltage-gated calcium channels (VGCC) play obligatory physiological roles, including modulation of neuronal: functions, synaptic plasticity, neurotransmitter release and gene transcription. Dysregulation and maladaptive changes in VGCC expression and activities may occur in the sensory pathway under various pathological conditions that could contribute to the development of pain. In this review, we summarized the most recent findings on the regulation of VGCC expression and physiological functions in the sensory pathway, and in dysregulation and maladaptive changes of VGCC under pain-inducing conditions. The implications of: these changes in understanding the mechanisms of pain transduction and in new drug design are also discussed.
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Affiliation(s)
- John Park
- Department of Pharmacology, University of California-Irvine School of Medicine, Irvine, CA, USA
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16
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Yarotskyy V, Elmslie KS. Interference between two modulators of N-type (CaV2.2) calcium channel gating demonstrates that ω-conotoxin GVIA disrupts open state gating. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1821-8. [DOI: 10.1016/j.bbamem.2010.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 04/22/2010] [Accepted: 05/05/2010] [Indexed: 10/19/2022]
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17
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Gowd KH, Yarotskyy V, Elmslie KS, Skalicky JJ, Olivera BM, Bulaj G. Site-specific effects of diselenide bridges on the oxidative folding of a cystine knot peptide, omega-selenoconotoxin GVIA. Biochemistry 2010; 49:2741-52. [PMID: 20175537 DOI: 10.1021/bi902137c] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Structural and functional studies of small, disulfide-rich peptides depend on their efficient chemical synthesis and folding. A large group of peptides derived from animals and plants contains the Cys pattern C-C-CC-C-C that forms the inhibitory cystine knot (ICK) or knottin motif. Here we report the effect of site-specific incorporation of pairs of selenocysteine residues on oxidative folding and the functional activity of omega-conotoxin GVIA, a well-characterized ICK-motif peptidic antagonist of voltage-gated calcium channels. Three selenoconotoxin GVIA analogues were chemically synthesized; all three folded significantly faster in the glutathione-based buffer compared to wild-type GVIA. One analogue, GVIA[C8U,C19U], exhibited significantly higher folding yields. A recently described NMR-based method was used for mapping the disulfide connectivities in the three selenoconotoxin analogues. The diselenide-directed oxidative folding of selenoconotoxins was predominantly driven by amino acid residue loop sizes formed by the resulting diselenide and disulfide cross-links. Both in vivo and in vitro activities of the analogues were assessed; the block of N-type calcium channels was comparable among the analogues and wild-type GVIA, suggesting that the diselenide replacement did not affect the bioactive conformation. Thus, diselenide substitution may facilitate oxidative folding of pharmacologically diverse ICK peptides. The diselenide replacement has been successfully applied to a growing number of bioactive peptides, including alpha-, mu-, and omega-conotoxins, suggesting that the integrated oxidative folding of selenopeptides described here may prove to be a general approach for efficient synthesis of diverse classes of disulfide-rich peptides.
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18
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Yarotskyy V, Elmslie KS. Open-state occupancy prevents gating charge relaxation of N-type (CaV2.2) calcium channels. Biophys J 2010; 97:2446-55. [PMID: 19883587 DOI: 10.1016/j.bpj.2009.08.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 07/17/2009] [Accepted: 08/06/2009] [Indexed: 10/20/2022] Open
Abstract
N-type and L-type channels have significant gating differences, and we wondered whether some of these differences are linked to the relationship between charge movement and channel opening. The time constants for N-channel closing (tau(Deact)) and Off-gating charge movement (tauQ(Off)) were compared over a range of voltages. tauQ(Off) was significantly larger than tau(Deact) at voltages < -10 mV, and the voltage dependence of the tauQ(Off) was less steep than that for tau(Deact), which suggests that gating charge relaxation does not limit channel closing. Roscovitine, a drug that slows N-channel closing by holding the channel in a high open-probability state, was found to slow both tauQ(Off) and tau(Deact), and thus the time courses of channel closing and gating charge relaxation were similar. Our gating current results were reproduced with the addition of a voltage-independent, closed-closed transition to our previously published two-open-state N-channel model. This work suggests that, like L-type channels, there is a voltage-independent transition along the N-channel activation/deactivation pathway, but this transition occurs between closed states instead of the closed-open states of the L-channel. Also unlike L-type channels, the gating charge appears to be locked into the activated position by the N-channel open state.
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Affiliation(s)
- Viktor Yarotskyy
- Department of Anesthesiology, Penn State College of Medicine, Penn State University, Hershey, Pennsylvania, USA
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19
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Perret D, Luo ZD. Targeting voltage-gated calcium channels for neuropathic pain management. Neurotherapeutics 2009; 6:679-92. [PMID: 19789072 PMCID: PMC2755636 DOI: 10.1016/j.nurt.2009.07.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Accepted: 07/09/2009] [Indexed: 01/08/2023] Open
Abstract
Voltage-gated calcium channels (VGCC) play obligatory roles in diverse physiological functions. Pathological conditions leading to changes in their biophysical properties and expression levels may cause malfunctions of VGCC-mediated activities, resulting in disease states. It is believed that changes in VGCC properties under pain-inducing conditions may play a causal role in the development of chronic pain, including nerve injury-induced pain or neuropathic pain. For the past several decades, preclinical and clinical research in developing VGCC blockers or modulators for chronic pain management has been fruitful, leading to some U.S. Food and Drug Administration-approved drugs currently available for chronic pain management. However, their efficacy in pain relief is limited in some patients, and their long-term use is limited by their side-effect profiles. Certainly, there is room for improvement in developing more subtype-specific VGCC blockers or modulators for chronic pain conditions. In this review, we summarized the most recent preclinical and clinical studies related to chronic pain medications acting on the VGCC. We also included clinical trials aiming to expand the application of approved VGCC drugs to different pain states derived from various pathological conditions, as well as drug combination therapies trying to improve the efficacies and side-effect profiles of current pain medications.
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Affiliation(s)
- Danielle Perret
- grid.266093.80000000106687243Department of Anesthesiology & Perioperative Care, University of California Irvine, 92697 Irvine, California
- grid.266093.80000000106687243Department of Physical Medicine & Rehabilitation, School of Medicine, University of California Irvine, 92697 Irvine, California
| | - Z. David Luo
- grid.266093.80000000106687243Department of Anesthesiology & Perioperative Care, University of California Irvine, 92697 Irvine, California
- grid.266093.80000000106687243Department of Pharmacology, University of California Irvine, 92697 Irvine, California
- grid.417319.9000000040434883XDepartment of Anesthesiology & Perioperative Care, University of California, Irvine Medical Center, Bldg 53, Room 227, 101 The City Dr. South, 92868 Orange, CA
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