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De Alwis AC, Denison JD, Shah R, McCarty GS, Sombers LA. Exploiting Microelectrode Geometry for Comprehensive Detection of Individual Exocytosis Events at Single Cells. ACS Sens 2023; 8:3187-3194. [PMID: 37552870 PMCID: PMC10464603 DOI: 10.1021/acssensors.3c00884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/25/2023] [Indexed: 08/10/2023]
Abstract
Carbon fiber microelectrodes are commonly used for real-time monitoring of individual exocytosis events at single cells. Since the nature of an electrochemical signal is fundamentally governed by mass transport to the electrode surface, microelectrode geometry can be exploited to achieve precise and accurate measurements. Researchers traditionally pair amperometric measurements of exocytosis with a ∼10-μm diameter, disk microelectrode in an "artificial synapse" configuration to directly monitor individual release events from single cells. Exocytosis is triggered, and released molecules diffuse to the "post-synaptic" electrode for oxidation. This results in a series of distinct current spikes corresponding to individual exocytosis events. However, it remains unclear how much of the material escapes detection. In this work, the performance of 10- and 34-μm diameter carbon fiber disk microelectrodes was directly compared in monitoring exocytosis at single chromaffin cells. The 34-μm diameter electrode was more sensitive to catecholamines and enkephalins than its traditional, 10-μm diameter counterpart, and it more effectively covered the entire cell. As such, the larger sensor detected more exocytosis events overall, as well as a larger quantal size, suggesting that the traditional tools underestimate the above measurements. Both sensors reliably measured l-DOPA-evoked changes in quantal size, and both exhibited diffusional loss upon adjustment of cell-electrode spacing. Finite element simulations using COMSOL support the improved collection efficiency observed using the larger sensor. Overall, this work demonstrates how electrode geometry can be exploited for improved detection of exocytosis events by addressing diffusional loss─an often-overlooked source of inaccuracy in single-cell measurements.
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Affiliation(s)
- A. Chathuri De Alwis
- Department
of Chemistry and Comparative Medicine Institute, North Carolina
State University, Raleigh, North Carolina 27695, United States
| | - J. Dylan Denison
- Department
of Chemistry and Comparative Medicine Institute, North Carolina
State University, Raleigh, North Carolina 27695, United States
| | - Ruby Shah
- Department
of Chemistry and Comparative Medicine Institute, North Carolina
State University, Raleigh, North Carolina 27695, United States
| | - Gregory S. McCarty
- Department
of Chemistry and Comparative Medicine Institute, North Carolina
State University, Raleigh, North Carolina 27695, United States
| | - Leslie A. Sombers
- Department
of Chemistry and Comparative Medicine Institute, North Carolina
State University, Raleigh, North Carolina 27695, United States
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2
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Bauer MB, Currie KPM. Serotonin and the serotonin transporter in the adrenal gland. VITAMINS AND HORMONES 2023; 124:39-78. [PMID: 38408804 DOI: 10.1016/bs.vh.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
The adrenal glands are key components of the mammalian endocrine system, helping maintain physiological homeostasis and the coordinated response to stress. Each adrenal gland has two morphologically and functionally distinct regions, the outer cortex and inner medulla. The cortex is organized into three concentric zones which secrete steroid hormones, including aldosterone and cortisol. Neural crest-derived chromaffin cells in the medulla are innervated by preganglionic sympathetic neurons and secrete catecholamines (epinephrine, norepinephrine) and neuropeptides into the bloodstream, thereby functioning as the neuroendocrine arm of the sympathetic nervous system. In this article we review serotonin (5-HT) and the serotonin transporter (SERT; SLC6A4) in the adrenal gland. In the adrenal cortex, 5-HT, primarily sourced from resident mast cells, acts as a paracrine signal to stimulate aldosterone and cortisol secretion through 5-HT4/5-HT7 receptors. Medullary chromaffin cells contain a small amount of 5-HT due to SERT-mediated uptake and express 5-HT1A receptors which inhibit secretion. The atypical mechanism of the 5-HT1A receptors and interaction with SERT fine tune this autocrine pathway to control stress-evoked catecholamine secretion. Receptor-independent signaling by SERT/intracellular 5-HT modulates the amount and kinetics of transmitter release from single vesicle fusion events. SERT might also influence stress-evoked upregulation of tyrosine hydroxylase transcription. Transient signaling via 5-HT3 receptors during embryonic development can limit the number of chromaffin cells found in the mature adrenal gland. Together, this emerging evidence suggests that the adrenal medulla is a peripheral hub for serotonergic control of the sympathoadrenal stress response.
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Affiliation(s)
- Mary Beth Bauer
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, South Broadway, Camden, NJ, United States
| | - Kevin P M Currie
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, South Broadway, Camden, NJ, United States.
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3
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Moriyama Y, Hasuzawa N, Nomura M. Is the vesicular nucleotide transporter a molecular target of eicosapentaenoic acid? Front Pharmacol 2022; 13:1080189. [PMID: 36569286 PMCID: PMC9768625 DOI: 10.3389/fphar.2022.1080189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Vesicular nucleotide transporter (VNUT), an active transporter for nucleotides in secretory vesicles, is responsible for the vesicular storage of ATP and plays an essential role in purinergic chemical transmission. Inhibition of VNUT decreases the concentration of ATP in the luminal space of secretory vesicles, followed by decreased vesicular ATP release, resulting in the blockade of purinergic chemical transmission. Very recently, Miyaji and colleagues reported that eicosapentaenoic acid (EPA) is a potent VNUT inhibitor and effective in treating neuropathic and inflammatory pain and insulin resistance through inhibition of vesicular storage and release of ATP. However, our validation study indicated that, in bovine adrenal chromaffin granule membrane vesicles, EPA inhibited the formation of an electrochemical gradient of protons across the membrane with the concentration of 50% inhibition (IC50) being 1.0 μM without affecting concanamycin B-sensitive ATPase activity. Essentially, similar results were obtained with proteoliposomes containing purified vacuolar H+-ATPase. Consistent with these observations, EPA inhibited the ATP-dependent uptakes of ATP and dopamine by chromaffin granule membrane vesicles, with ID50 being 1.2 and 1.0 μM, respectively. Furthermore, EPA inhibited ATP-dependent uptake of L-glutamate by mouse brain synaptic vesicles with ID50 being 0.35 μM. These results indicate that EPA at sub-μM acts as a proton conductor and increases proton permeability across the membrane, regardless of the presence or absence of VNUT, thereby inhibiting non-specifically the vesicular storage of neurotransmitters. Thus, EPA may affect a broader range of chemical transmission than proposed.
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Hatamie A, He X, Zhang XW, Oomen PE, Ewing AG. Advances in nano/microscale electrochemical sensors and biosensors for analysis of single vesicles, a key nanoscale organelle in cellular communication. Biosens Bioelectron 2022; 220:114899. [DOI: 10.1016/j.bios.2022.114899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022]
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5
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Aref M, Ranjbari E, Romiani A, Ewing AG. Intracellular injection of phospholipids directly alters exocytosis and the fraction of chemical release in chromaffin cells as measured by nano-electrochemistry. Chem Sci 2020; 11:11869-11876. [PMID: 34123212 PMCID: PMC8162797 DOI: 10.1039/d0sc03683h] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 10/06/2020] [Indexed: 12/02/2022] Open
Abstract
Using a nano-injection method, we introduced phospholipids having different intrinsic geometries into single secretory cells and used single cell amperometry (SCA) and intracellular vesicle impact electrochemical cytometry (IVIEC) with nanotip electrodes to monitor the effects of intracellular incubation on the exocytosis process and vesicular storage. Combining tools, this work provides new information to understand the impact of intracellular membrane lipid engineering on exocytotic release, vesicular content and fraction of chemical release. We also assessed the effect of membrane lipid alteration on catecholamine storage of isolated vesicles by implementing another amperometric technique, vesicle impact electrochemical cytometry (VIEC), outside the cell. Exocytosis analysis reveals that the intracellular nano-injection of phosphatidylcholine and lysophosphatidylcholine decreases the number of released catecholamines, whereas phosphatidylethanolamine shows the opposite effect. These observations support the emerging hypothesis that lipid curvature results in membrane remodeling through secretory pathways, and also provide new evidence for a critical role of the lipid localization in modulating the release process. Interestingly, the IVIEC data imply that total vesicular content is also affected by in situ supplementation of the cells with some lipids, while, the corresponding VIEC results show that the neurotransmitter content in isolated vesicles is not affected by altering the vesicle membrane lipids. This suggests that the intervention of phospholipids inside the cell has its effect on the cellular machinery for vesicle release rather than vesicle structure, and leads to the somewhat surprising conclusion that modulating release has a direct effect on vesicle structure, which is likely due to the vesicles opening and closing again during exocytosis. These findings could lead to a novel regulatory mechanism for the exocytotic or synaptic strength based on lipid heterogeneity across the cell membrane.
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Affiliation(s)
- Mohaddeseh Aref
- Department of Chemistry and Molecular Biology, University of Gothenburg Gothenburg Sweden
| | - Elias Ranjbari
- Department of Chemistry and Molecular Biology, University of Gothenburg Gothenburg Sweden
| | - Armaghan Romiani
- Department of Chemistry and Molecular Biology, University of Gothenburg Gothenburg Sweden
| | - Andrew G Ewing
- Department of Chemistry and Molecular Biology, University of Gothenburg Gothenburg Sweden
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6
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Roberts JG, Mitchell EC, Dunaway LE, McCarty GS, Sombers LA. Carbon-Fiber Nanoelectrodes for Real-Time Discrimination of Vesicle Cargo in the Native Cellular Environment. ACS NANO 2020; 14:2917-2926. [PMID: 32058693 PMCID: PMC7336535 DOI: 10.1021/acsnano.9b07318] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Carbon-fiber microelectrodes have proven to be an indispensable tool for monitoring exocytosis events using amperometry. When positioned adjacent to a cell, a traditional microdisc electrode is well suited for quantification of discrete exocytotic release events. However, the size of the electrode does not allow for intracellular electrochemical measurements, and the amperometric approach cannot distinguish between the catecholamines that are released. In this work, carbon nanoelectrodes were developed to permit selective electrochemical sampling of nanoscale vesicles in the cell cytosol. Classical voltammetric techniques and electron microscopy were used to characterize the nanoelectrodes, which were ∼5 μm long and sharpened to a nanometer-scale tip that could be wholly inserted into individual neuroendocrine cells. The nanoelectrodes were coupled with fast-scan cyclic voltammetry to distinguish secretory granules containing epinephrine from other catecholamine-containing granules encountered in the native cellular environment. Both vesicle subtypes were encountered in most cells, despite prior demonstration of populations of chromaffin cells that preferentially release one of these catecholamines. There was substantial cell-to-cell variability in relative epinephrine content, and vesicles containing epinephrine generally stored more catecholamine than the other vesicles. The carbon nanoelectrode technology thus enabled analysis of picoliter-scale biological volumes, revealing key differences between chromaffin cells at the level of the dense-core granule.
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Zhang XW, Hatamie A, Ewing AG. Simultaneous Quantification of Vesicle Size and Catecholamine Content by Resistive Pulses in Nanopores and Vesicle Impact Electrochemical Cytometry. J Am Chem Soc 2020; 142:4093-4097. [PMID: 32069039 PMCID: PMC7108759 DOI: 10.1021/jacs.9b13221] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
We have developed the means to simultaneously
measure the physical
size and count catecholamine molecules in individual nanometer transmitter
vesicles. This is done by combining resistive pulse (RP) measurements
in a nanopore pipet and vesicle impact electrochemical cytometry (VIEC)
at an electrode as the vesicle exits the nanopore. Analysis of freshly
isolated bovine adrenal vesicles shows that the size and internal
catecholamine concentration of vesicles varies with the occurrence
of a dense core inside the vesicles. These results might benefit the
understanding about the vesicles maturation, especially involving
the “sorting by retention” process and concentration
increase of intravesicular catecholamine. The methodology is applicable
to understanding soft nanoparticle collisions on electrodes, vesicles
in exocytosis and phagocytosis, intracellular vesicle transport, and
analysis of electroactive drugs in exosomes.
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Affiliation(s)
- Xin-Wei Zhang
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Amir Hatamie
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Andrew G Ewing
- Department of Chemistry and Molecular Biology, University of Gothenburg, SE-412 96 Gothenburg, Sweden
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8
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Soslau G. Extracellular adenine compounds within the cardiovascular system: Their source, metabolism and function. MEDICINE IN DRUG DISCOVERY 2019. [DOI: 10.1016/j.medidd.2020.100018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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9
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González-Santana A, Castañeyra L, Baz-Dávila R, Estévez-Herrera J, Domínguez N, Méndez-López I, Padín JF, Castañeyra A, Machado JD, Ebert SN, Borges R. Adrenergic chromaffin cells are adrenergic even in the absence of epinephrine. J Neurochem 2019; 152:299-314. [PMID: 31677273 DOI: 10.1111/jnc.14904] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/24/2019] [Accepted: 10/29/2019] [Indexed: 11/30/2022]
Abstract
Adrenal chromaffin cells release epinephrine (EPI) and norepinephrine (NE) into the bloodstream as part of the homeostatic response to situations like stress. Here we utilized EPI-deficient mice generated by knocking out (KO) the phenylethanolamine N-methyltransferase (Pnmt) gene. These Pnmt-KO mice were bred to homozygosis but displayed no major phenotype. The lack of EPI was partially compensated by an increase in NE, suggesting that EPI storage was optimized in adrenergic cells. Electron microscopy showed that despite the lack of EPI, chromaffin granules retain their shape and general appearance. This indicate that granules from adrenergic or noradrenergic cells preserve their characteristics even though they contain only NE. Acute insulin injection largely reduced the EPI content in wild-type animals, with a minimal reduction in NE, whereas there was only a partial reduction in NE content in Pnmt-KO mice. The analysis of exocytosis by amperometry revealed a reduction in the quantum size (-30%) and Imax (-21%) of granules in KO cells relative to the wild-type granules, indicating a lower affinity of NE for the granule matrix of adrenergic cells. As amperometry cannot distinguish between adrenergic or noradrenergic cells, it would suggest even a larger reduction in the affinity for the matrix. Therefore, our results demonstrate that adrenergic cells retain their structural characteristics despite the almost complete absence of EPI. Furthermore, the chromaffin granule matrix from adrenergic cells is optimized to accumulate EPI, with NE being a poor substitute. Open Science: This manuscript was awarded with the Open Materials Badge For more information see: https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
| | - Leandro Castañeyra
- Unidad de Farmacología, Facultad de Medicina, Universidad de la Laguna, Tenerife, Spain
| | - Rebeca Baz-Dávila
- Unidad de Farmacología, Facultad de Medicina, Universidad de la Laguna, Tenerife, Spain
| | | | - Natalia Domínguez
- INTEGRARE, Généthon, Inserm, Univ Evry, Université Paris-Saclay, Evry, France
| | - Iago Méndez-López
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, Madrid, Spain
| | - J Fernando Padín
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, Madrid, Spain.,Departamento Ciencias Médicas (Farmacología), Facultad de Medicina, Universidad de Castilla-La Mancha, Ciudad Real, Spain
| | - Agustín Castañeyra
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad de La Laguna, Tenerife, Spain
| | - José-David Machado
- Unidad de Farmacología, Facultad de Medicina, Universidad de la Laguna, Tenerife, Spain
| | - Steven N Ebert
- Division of Metabolic and Cardiovascular Sciences, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Ricardo Borges
- Unidad de Farmacología, Facultad de Medicina, Universidad de la Laguna, Tenerife, Spain
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de Pascual R, Álvarez-Ortego N, de Los Ríos C, Jacob-Mazariego G, García AG. Tetrabenazine Facilitates Exocytosis by Enhancing Calcium-Induced Calcium Release through Ryanodine Receptors. J Pharmacol Exp Ther 2019; 371:219-230. [PMID: 31209099 DOI: 10.1124/jpet.119.256560] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 06/04/2019] [Indexed: 11/22/2022] Open
Abstract
Vesicular monoamine transporter-2 is expressed in the presynaptic secretory vesicles membrane in the brain. Its blockade by tetrabenazine (TBZ) causes depletion of dopamine at striatal basal ganglia; this is the mechanism underlying its long-standing use in the treatment of Huntington's disease. In the frame of a project aimed at investigating the kinetics of exocytosis from vesicles with partial emptying of their neurotransmitter, we unexpectedly found that TBZ facilitates exocytosis; thus, we decided to characterize such effect. We used bovine chromaffin cells (BCCs) challenged with repeated pulses of high K+ Upon repeated K+ pulsing, the exocytotic catecholamine release responses were gradually decaying. However, when cells were exposed to TBZ, responses were mildly augmented and decay rate delayed. Facilitation of exocytosis was not due to Ca2+ entry blockade through voltage-activated calcium channels (VACCs) because, in fact, TBZ mildly blocked the whole-cell Ca2+ current. However, TBZ mimicked the facilitatory effects of exocytosis elicited by BayK8644 (L-subtype VACC agonist), an effect blocked by nifedipine (VACC antagonist). On the basis that TBZ augmented the secretory responses to caffeine (but not those of histamine), we monitored its effects on cytosolic Ca2+ elevations ([Ca2+]c) triggered by caffeine or histamine. While the responses to caffeine were augmented twice by TBZ, those of histamine were unaffected; the same happened in rat cortical neurons. Hence, we hypothesize that TBZ facilitates exocytosis by increasing Ca2+ release through the endoplasmic reticulum ryanodine receptor channel (RyR). Confirming this hypothesis are docking results, showing an interaction of TBZ with RyRs. This is consonant with the existence of a healthy Ca2+-induced-Ca2+-release mechanism in BCCs. SIGNIFICANCE STATEMENT: A novel mechanism of action for tetrabenazine (TBZ), a drug used in the therapy of Huntington's disease (HD), is described here. Such mechanism consists of facilitation by combining TBZ with the ryanodine receptor of the endoplasmic reticulum, thereby increasing Ca2+-induced Ca2+ release. This novel mechanism should be taken into account when considering the efficacy and/or safety of TBZ in the treatment of chorea associated with HD and other disorders. Additionally, it could be of interest in the development of novel medicines to treat these pathological conditions.
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Affiliation(s)
- Ricardo de Pascual
- Instituto Teófilo Hernando, Madrid, Spain (R.d.P., N.Á.-O., C.d.l.R., G.J.-M., A.G.G.); and Departamento de Farmacología y Terapéutica (R.d.P., N.Á.-O., G.J.-M., A.G.G.) and Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa (C.d.l.R., A.G.G.), Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Nuria Álvarez-Ortego
- Instituto Teófilo Hernando, Madrid, Spain (R.d.P., N.Á.-O., C.d.l.R., G.J.-M., A.G.G.); and Departamento de Farmacología y Terapéutica (R.d.P., N.Á.-O., G.J.-M., A.G.G.) and Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa (C.d.l.R., A.G.G.), Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Cristóbal de Los Ríos
- Instituto Teófilo Hernando, Madrid, Spain (R.d.P., N.Á.-O., C.d.l.R., G.J.-M., A.G.G.); and Departamento de Farmacología y Terapéutica (R.d.P., N.Á.-O., G.J.-M., A.G.G.) and Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa (C.d.l.R., A.G.G.), Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Gema Jacob-Mazariego
- Instituto Teófilo Hernando, Madrid, Spain (R.d.P., N.Á.-O., C.d.l.R., G.J.-M., A.G.G.); and Departamento de Farmacología y Terapéutica (R.d.P., N.Á.-O., G.J.-M., A.G.G.) and Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa (C.d.l.R., A.G.G.), Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio G García
- Instituto Teófilo Hernando, Madrid, Spain (R.d.P., N.Á.-O., C.d.l.R., G.J.-M., A.G.G.); and Departamento de Farmacología y Terapéutica (R.d.P., N.Á.-O., G.J.-M., A.G.G.) and Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa (C.d.l.R., A.G.G.), Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
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11
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Kim BH, Wang FI, Pereverzev A, Chidiac P, Dixon SJ. Toward Defining the Pharmacophore for Positive Allosteric Modulation of PTH1 Receptor Signaling by Extracellular Nucleotides. ACS Pharmacol Transl Sci 2019; 2:155-167. [PMID: 32259054 DOI: 10.1021/acsptsci.8b00053] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Indexed: 12/17/2022]
Abstract
The parathyroid hormone 1 receptor (PTH1R) is a Class B G-protein-coupled receptor that is a target for osteoporosis therapeutics. Activated PTH1R couples through Gs to the stimulation of adenylyl cyclase. As well, β-arrestin is recruited to PTH1R leading to receptor internalization and MAPK/ERK signaling. Previously, we reported that the agonist potency of PTH1R is increased in the presence of extracellular ATP, which acts as a positive allosteric modulator of PTH signaling. Another nucleotide, cytidine 5'-monophosphate (CMP), also enhances PTH1R signaling, suggesting that ATP and CMP share a moiety responsible for positive allostery, possibly ribose-5-phosphate. Therefore, we examined the effect of extracellular sugar phosphates on PTH1R signaling. cAMP levels and β-arrestin recruitment were monitored using luminescence-based assays. Alone, ribose-5-phosphate had no detectable effect on adenylyl cyclase activity in UMR-106 rat osteoblastic cells, which endogenously express PTH1R. However, ribose-5-phosphate markedly enhanced the activation of adenylyl cyclase induced by PTH. Other sugar phosphates, including glucose-1-phosphate, glucose-6-phosphate, fructose-6-phosphate, and fructose-1,6-bisphosphate, also potentiated PTH-induced adenylyl cyclase activation. As well, some sugar phosphates enhanced PTH-induced β-arrestin recruitment to human PTH1R heterologously expressed in HEK293H cells. Interestingly, the effects of glucose-1-phosphate were greater than those of its isomer glucose-6-phosphate. Our results suggest that phosphorylated monosaccharides such as ribose-5-phosphate contain the pharmacophore for positive allosteric modulation of PTH1R. At least in some cases, the extent of modulation depends on the position of the phosphate group. Knowledge of the pharmacophore may permit future development of positive allosteric modulators to increase the therapeutic efficacy of PTH1R agonists.
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Affiliation(s)
- Brandon H Kim
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry; and Bone and Joint Institute; The University of Western Ontario, London, Canada
| | - Fang I Wang
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry; and Bone and Joint Institute; The University of Western Ontario, London, Canada
| | - Alexey Pereverzev
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry; and Bone and Joint Institute; The University of Western Ontario, London, Canada
| | - Peter Chidiac
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry; and Bone and Joint Institute; The University of Western Ontario, London, Canada
| | - S Jeffrey Dixon
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry; and Bone and Joint Institute; The University of Western Ontario, London, Canada
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12
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Liu X, Tong Y, Fang PP. Recent development in amperometric measurements of vesicular exocytosis. Trends Analyt Chem 2019. [DOI: 10.1016/j.trac.2019.01.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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13
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Affiliation(s)
- Pieter E. Oomen
- University of Gothenburg, Department of Chemistry and Molecular Biology, Gothenburg 41296, Sweden
| | - Mohaddeseh A. Aref
- University of Gothenburg, Department of Chemistry and Molecular Biology, Gothenburg 41296, Sweden
| | - Ibrahim Kaya
- University of Gothenburg, Department of Chemistry and Molecular Biology, Gothenburg 41296, Sweden
- Department of Psychiatry and Neurochemistry, Sahlgrenska Academy at the University of Gothenburg, Mölndal Hospital, House V3, 43180 Mölndal, Sweden
- The Gothenburg Imaging Mass Spectrometry (Go:IMS) Laboratory, University of Gothenburg and Chalmers University of Technology, Gothenburg 41296, Sweden
| | - Nhu T. N. Phan
- University of Gothenburg, Department of Chemistry and Molecular Biology, Gothenburg 41296, Sweden
- The Gothenburg Imaging Mass Spectrometry (Go:IMS) Laboratory, University of Gothenburg and Chalmers University of Technology, Gothenburg 41296, Sweden
- University of Göttingen Medical Center, Institute of Neuro- and Sensory Physiology, Göttingen 37073, Germany
| | - Andrew G. Ewing
- University of Gothenburg, Department of Chemistry and Molecular Biology, Gothenburg 41296, Sweden
- The Gothenburg Imaging Mass Spectrometry (Go:IMS) Laboratory, University of Gothenburg and Chalmers University of Technology, Gothenburg 41296, Sweden
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