1
|
Yin P, Wang H, Xue T, Yu X, Meng X, Mi Q, Song S, Xiong B, Bi Y, Yu L. Four-Dimensional Label-Free Quantitative Proteomics of Ginsenoside Rg 2 Ameliorated Scopolamine-Induced Memory Impairment in Mice through the Lysosomal Pathway. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:14640-14652. [PMID: 38885433 DOI: 10.1021/acs.jafc.4c00181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease. Ginsenoside Rg2 has shown potential in treating AD, but the underlying protein regulatory mechanisms associated with ginsenoside Rg2 treatment for AD remain unclear. This study utilized scopolamine to induce memory impairment in mice, and proteomics methods were employed to investigate the potential molecular mechanism of ginsenoside Rg2 in treating AD model mice. The Morris water maze, hematoxylin and eosin staining, and Nissl staining results indicated that ginsenoside Rg2 enhanced cognitive ability and decreased neuronal damage in AD mice. Proteomics, western blot, and immunofluorescence results showed that ginsenoside Rg2 primarily improved AD mice by downregulating the expression of LGMN, LAMP1, and PSAP proteins through the regulation of the lysosomal pathway. Transmission electron microscopy and network pharmacology prediction results showed a potential connection between the mechanism of ginsenoside Rg2 treatment for AD mice and lysosomes. The comprehensive results indicated that ginsenoside Rg2 may improve AD by downregulating LGMN, LAMP1, and PSAP through the regulation of the lysosomal pathway.
Collapse
Affiliation(s)
- Pei Yin
- College of Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China
| | - Heyu Wang
- College of Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China
| | - Tingfang Xue
- College of Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China
| | - Xiaoran Yu
- College of Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China
| | - Xingjian Meng
- College of Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China
| | - Qianwen Mi
- College of Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China
| | - Shixin Song
- College of Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China
| | - Boyu Xiong
- College of Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China
| | - Yunfeng Bi
- College of Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China
| | - Lei Yu
- College of Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China
| |
Collapse
|
2
|
Xu R, Wan M, Shi X, Ma S, Zhang L, Yi P, Zhang R. A Rab10-ACAP1-Arf6 GTPases cascade modulates M4 muscarinic acetylcholine receptor trafficking and signaling. Cell Mol Life Sci 2023; 80:87. [PMID: 36917255 PMCID: PMC11072986 DOI: 10.1007/s00018-023-04722-x] [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: 11/27/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 03/16/2023]
Abstract
Membrane trafficking processes regulate the G protein-coupled receptor activity. The muscarinic acetylcholine receptors (mAChRs) are highly pursued drug targets for neurological diseases, but the cellular machineries that control the trafficking of these receptors remain largely elusive. Here, we revealed the role of the small GTPase Rab10 as a negative regulator for the post-activation trafficking of M4 mAChR and the underlying mechanism. We show that constitutively active Rab10 arrests the receptor within Rab5-positive early endosomes and significantly hinders the resensitization of M4-mediated Ca2+ signaling. Mechanistically, M4 binds to Rab10-GTP, which requires the motif 386RKKRQMAA393 (R386-A393) within the third intracellular loop. Moreover, Rab10-GTP inactivates Arf6 by recruiting the Arf6 GTPase-activating protein, ACAP1. Strikingly, deletion of the motif R386-A393 causes M4 to bypass the control by Rab10 and switch to the Rab4-facilitated fast recycling pathway, thus reusing the receptor. Therefore, Rab10 couples the cargo sorting and membrane trafficking regulation through cycle between GTP-bound and GDP-bound state. Our findings suggest a model that Rab10 binds to the M4 like a molecular brake and controls the receptor's transport through endosomes, thus modulating the signaling, and this regulation is specific among the mAChR subtypes.
Collapse
Affiliation(s)
- Rongmei Xu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Min Wan
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, USA
| | - Xuemeng Shi
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- College of Life Science, Henan Agricultural University, Zhengzhou, Henan, China
| | - Shumin Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Lina Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ping Yi
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China.
| | - Rongying Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China.
| |
Collapse
|
3
|
Kumar GA, Puthenveedu MA. Diversity and specificity in location-based signaling outputs of neuronal GPCRs. Curr Opin Neurobiol 2022; 76:102601. [DOI: 10.1016/j.conb.2022.102601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/27/2022] [Accepted: 06/01/2022] [Indexed: 11/30/2022]
|
4
|
Chaudhary PK, Kim S. The GRKs Reactome: Role in Cell Biology and Pathology. Int J Mol Sci 2021; 22:ijms22073375. [PMID: 33806057 PMCID: PMC8036551 DOI: 10.3390/ijms22073375] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/21/2021] [Accepted: 03/22/2021] [Indexed: 02/06/2023] Open
Abstract
G protein-coupled receptor kinases (GRKs) are protein kinases that function in concert with arrestins in the regulation of a diverse class of G protein-coupled receptors (GPCRs) signaling. Although GRKs and arrestins are key participants in the regulation of GPCR cascades, the complex regulatory mechanisms of GRK expression, its alternation, and their function are not thoroughly understood. Several studies together with the work from our lab in recent years have revealed the critical role of these kinases in various physiological and pathophysiological processes, including cardiovascular biology, inflammation and immunity, neurodegeneration, thrombosis, and hemostasis. A comprehensive understanding of the mechanisms underlying functional interactions with multiple receptor proteins and how these interactions take part in the development of various pathobiological processes may give rise to novel diagnostic and therapeutic strategies. In this review, we summarize the current research linking the role of GRKs to various aspects of cell biology, pathology, and therapeutics, with a particular focus on thrombosis and hemostasis.
Collapse
|
5
|
Gurevich EV, Gurevich VV. GRKs as Modulators of Neurotransmitter Receptors. Cells 2020; 10:cells10010052. [PMID: 33396400 PMCID: PMC7823573 DOI: 10.3390/cells10010052] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 12/23/2020] [Accepted: 12/30/2020] [Indexed: 01/08/2023] Open
Abstract
Many receptors for neurotransmitters, such as dopamine, norepinephrine, acetylcholine, and neuropeptides, belong to the superfamily of G protein-coupled receptors (GPCRs). A general model posits that GPCRs undergo two-step homologous desensitization: the active receptor is phosphorylated by kinases of the G protein-coupled receptor kinase (GRK) family, whereupon arrestin proteins specifically bind active phosphorylated receptors, shutting down G protein-mediated signaling, facilitating receptor internalization, and initiating distinct signaling pathways via arrestin-based scaffolding. Here, we review the mechanisms of GRK-dependent regulation of neurotransmitter receptors, focusing on the diverse modes of GRK-mediated phosphorylation of receptor subtypes. The immediate signaling consequences of GRK-mediated receptor phosphorylation, such as arrestin recruitment, desensitization, and internalization/resensitization, are equally diverse, depending not only on the receptor subtype but also on phosphorylation by GRKs of select receptor residues. We discuss the signaling outcome as well as the biological and behavioral consequences of the GRK-dependent phosphorylation of neurotransmitter receptors where known.
Collapse
|
6
|
Inagaki RT, Raghuraman S, Chase K, Steele T, Zornik E, Olivera B, Yamaguchi A. Molecular characterization of frog vocal neurons using constellation pharmacology. J Neurophysiol 2020; 123:2297-2310. [PMID: 32374212 DOI: 10.1152/jn.00105.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Identification and characterization of neuronal cell classes in motor circuits are essential for understanding the neural basis of behavior. It is a challenging task, especially in a non-genetic-model organism, to identify cell-specific expression of functional macromolecules. Here, we performed constellation pharmacology, calcium imaging of dissociated neurons to pharmacologically identify functional receptors expressed by vocal neurons in adult male and female African clawed frogs, Xenopus laevis. Previously we identified a population of vocal neurons called fast trill neurons (FTNs) in the amphibian parabrachial nucleus (PB) that express N-methyl-d-aspartate (NMDA) receptors and GABA and/or glycine receptors. Using constellation pharmacology, we identified four cell classes of putative fast trill neurons (pFTNs, responsive to both NMDA and GABA/glycine applications). We discovered that some pFTNs responded to the application of substance P (SP), acetylcholine (ACh), or both. Electrophysiological recordings obtained from FTNs using an ex vivo preparation verified that SP and/or ACh depolarize FTNs. Bilateral injection of ACh, SP, or their antagonists into PBs showed that ACh receptors are not sufficient but necessary for vocal production, and SP receptors play a role in shaping the morphology of vocalizations. Additionally, we discovered that the PB of adult female X. laevis also contains all the subclasses of neurons at a similar frequency as in males, despite their sexually distinct vocalizations. These results reveal novel neuromodulators that regulate X. laevis vocal production and demonstrate the power of constellation pharmacology in identifying the neuronal subtypes marked by functional expression of cell-specific receptors in non-genetic-model organisms.NEW & NOTEWORTHY Molecular profiles of neurons are critical for understanding the neuronal functions, but their identification is challenging especially in non-genetic-model organisms. Here, we characterized the functional expression of membrane macromolecules in vocal neurons of African clawed frogs, Xenopus laevis, using a technique called constellation pharmacology. We discovered that receptors for acetylcholine and/or substance P are expressed by some classes of vocal neurons, and their activation plays a role in the production of normal vocalizations.
Collapse
Affiliation(s)
- Ryota T Inagaki
- School of Biological Sciences, University of Utah, Salt Lake City, Utah
| | | | - Kevin Chase
- School of Biological Sciences, University of Utah, Salt Lake City, Utah
| | | | - Erik Zornik
- Biology Department, Reed College, Portland, Oregon
| | - Baldomero Olivera
- School of Biological Sciences, University of Utah, Salt Lake City, Utah
| | - Ayako Yamaguchi
- School of Biological Sciences, University of Utah, Salt Lake City, Utah
| |
Collapse
|
7
|
hTAC internalizes via both clathrin-dependent and clathrin-independent endocytosis in mammalian cells. Protein Cell 2019; 9:896-901. [PMID: 29549600 PMCID: PMC6160390 DOI: 10.1007/s13238-018-0508-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
8
|
Berndt‐Paetz M, Herbst L, Weimann A, Gonsior A, Stolzenburg J, Neuhaus J. IC/BPS‐associated alterations of M2 and M3 muscarinic acetylcholine receptor trafficking in human detrusor. Neurourol Urodyn 2019; 38:1818-1827. [DOI: 10.1002/nau.24087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/10/2019] [Indexed: 12/26/2022]
Affiliation(s)
- Mandy Berndt‐Paetz
- Department of Urology, Research LaboratoriesUniversity of Leipzig Leipzig Germany
| | - Luise Herbst
- Department of Urology, Research LaboratoriesUniversity of Leipzig Leipzig Germany
| | - Annett Weimann
- Department of Urology, Research LaboratoriesUniversity of Leipzig Leipzig Germany
| | - Andreas Gonsior
- Department of UrologyUniversity Hospital Leipzig AöR Leipzig Germany
| | | | - Jochen Neuhaus
- Department of Urology, Research LaboratoriesUniversity of Leipzig Leipzig Germany
| |
Collapse
|
9
|
Sales ME, Español AJ, Salem AR, Pulido PM, Sanchez Y, Sanchez F. Role of Muscarinic Acetylcholine Receptors in Breast Cancer: Design of Metronomic Chemotherapy. CURRENT CLINICAL PHARMACOLOGY 2019; 14:91-100. [PMID: 30501602 PMCID: PMC7011678 DOI: 10.2174/1574884714666181203095437] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND muscarinic acetylcholine receptors (mAChRs) have attracted interest as targets for therapeutic interventions in different illnesses like Alzheimer´s disease, viral infections and different tumors. Regarding the latter, many authors have studied each subtype of mAChRs, which seem to be involved in the progression of distinct types of malignancies. METHODS We carefully revised research literature focused on mAChRs expression and signaling as well as in their involvement in cancer progression and treatment. The characteristics of screened papers were described using the mentioned conceptual framework. RESULTS Muscarinic antagonists and agonists have been assayed for the treatment of tumors established in lung, brain and breast with beneficial effects. We described an up-regulation of mAChRs in mammary tumors and the lack of expression in non-tumorigenic breast cells and normal mammary tissues. We and others demonstrated that muscarinic agonists can trigger anti-tumor actions in a dose-dependent manner on tumors originated in different organs like brain or breast. At pharmacological concentrations, they exert similar effects to traditional chemotherapeutic agents. Metronomic chemotherapy refers to the administration of anti-cancer drugs at low doses with short intervals among them, and it is a different regimen applied in cancer treatment reducing malignant growth and angiogenesis, and very low incidence of adverse effects. CONCLUSION The usage of subthreshold concentrations of muscarinic agonists combined with conventional chemotherapeutic agents could be a promising tool for breast cancer therapy.
Collapse
Affiliation(s)
- María E. Sales
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO)-CONICET. 2da Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Alejandro J. Español
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO)-CONICET. 2da Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Agustina R. Salem
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO)-CONICET. 2da Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Paola M. Pulido
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO)-CONICET. 2da Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Y. Sanchez
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO)-CONICET. 2da Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Francisco Sanchez
- Centro de Estudios Farmacológicos y Botánicos (CEFYBO)-CONICET. 2da Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| |
Collapse
|
10
|
Lambert L, Dubayle D, Fafouri A, Herzog E, Csaba Z, Dournaud P, El Mestikawy S, Bernard V. Endocytosis of Activated Muscarinic m2 Receptor (m2R) in Live Mouse Hippocampal Neurons Occurs via a Clathrin-Dependent Pathway. Front Cell Neurosci 2018; 12:450. [PMID: 30555302 PMCID: PMC6283979 DOI: 10.3389/fncel.2018.00450] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/07/2018] [Indexed: 02/02/2023] Open
Abstract
Our aim was to examine the dynamics of the muscarinic m2 receptor (m2R), a G-protein coupled receptor (GPCR), after agonist activation in living hippocampal neurons, and especially clathrin dependency endocytosis. We have previously shown that the m2R undergoes agonist-induced internalization in vivo. However, the nature of the endocytotic pathway used by m2R after activation is still unknown in living neurons. Using live cell imaging and quantitative analyses, we have monitored the effect of stimulation on the fate of the membrane-bound m2R and on its redistribution in intraneuronal compartments. Shortly (6 min) after activation, m2R is internalized into clathrin immunopositive structures. Furthermore, after clathrin-dependent endocytosis, m2R associates with early and late endosomes and with subcellular organelles involved in degradation. Together, these results provide, for the first time, a description of m2R trafficking in living neurons and prove that m2R undergoes clathrin-dependent endocytosis before being degraded.
Collapse
Affiliation(s)
- Lisa Lambert
- Sorbonne Université, Université Pierre et Marie Curie UM 119 - CNRS UMR 8246 - INSERM U1130, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), Paris, France
| | - David Dubayle
- Sorbonne Université, Université Pierre et Marie Curie UM 119 - CNRS UMR 8246 - INSERM U1130, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), Paris, France.,Université Paris Descartes - CNRS UMR 8119, Centre de Neurophysique, Physiologie et Pathologie, Paris, France
| | - Assia Fafouri
- PROTECT, INSERM U1141, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Etienne Herzog
- Sorbonne Université, Université Pierre et Marie Curie UM 119 - CNRS UMR 8246 - INSERM U1130, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), Paris, France.,Interdisciplinary Institute for Neuroscience, University Bordeaux, UMR 5297, Bordeaux, France.,Interdisciplinary Institute for Neuroscience, CNRS, UMR 5297, Bordeaux, France
| | - Zsolt Csaba
- PROTECT, INSERM U1141, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Pascal Dournaud
- PROTECT, INSERM U1141, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Salah El Mestikawy
- Sorbonne Université, Université Pierre et Marie Curie UM 119 - CNRS UMR 8246 - INSERM U1130, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), Paris, France.,Department of Psychiatry, Douglas Hospital Research Center, McGill University, Montréal, QC, Canada
| | - Véronique Bernard
- Sorbonne Université, Université Pierre et Marie Curie UM 119 - CNRS UMR 8246 - INSERM U1130, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), Paris, France
| |
Collapse
|
11
|
Zenko D, Hislop JN. Regulation and trafficking of muscarinic acetylcholine receptors. Neuropharmacology 2017; 136:374-382. [PMID: 29138081 DOI: 10.1016/j.neuropharm.2017.11.017] [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: 09/21/2016] [Revised: 11/02/2017] [Accepted: 11/10/2017] [Indexed: 12/31/2022]
Abstract
Fidelity of signal transduction relies on cells expressing the appropriate number of functional receptors. Fluctuation in the total number of muscarinic acetylcholine receptors has been implicated in a range of physiological and pathophysiological processes, and the mechanisms responsible for this regulation represent potential molecular targets for therapeutic intervention. This article will review the current literature on the endocytic trafficking of muscarinic receptors and how knowledge of the trafficking of related receptors might influence future studies. This article is part of the Special Issue entitled 'Neuropharmacology on Muscarinic Receptors'.
Collapse
Affiliation(s)
- Dmitry Zenko
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - James N Hislop
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom.
| |
Collapse
|
12
|
Early changes in M2 muscarinic acetylcholine receptors (mAChRs) induced by sarin intoxication may be linked to long lasting neurological effects. Neurotoxicology 2017; 65:248-254. [PMID: 29128314 DOI: 10.1016/j.neuro.2017.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 11/05/2017] [Accepted: 11/05/2017] [Indexed: 01/08/2023]
Abstract
The effect of sarin on the binding parameters (KD & Bmax) of M2 muscarinic acetylcholine receptor (mAChR) was studied 24h and 1 week post exposure. Male & female Sprague-Daweley rats were poisoned with 1XLD50 sarin (80μg/kg, im) followed by treatment of trimedoxime bromide and atropine (7.5:5mg/kg, im) 1min later. Brains were removed and analyzed for M2 mAChR binding, using [3H]AFDX384, an M2 selective antagonist. A significant increase in KD of M2 mAChR was found in the cortex 24h post poisoning, displaying elevation from 4.65±1.16 to 8.45±1.06nM and 5.24±0.93 to 9.29±1.56nM in male and female rats, respectively. A rise in KD was also noted 1 week following exposure from 5.04±1.20 to 11.75±2.78 and from 5.37±1.02 to 11.66±1.73nM, presenting an added increase of 51 and 40% (compared to 24h) in males and females, respectively. Analysis of M2 receptor density (Bmax) revealed a significant reduction of 68% in males and insignificant reduction of 22% in females, 24h after sarin exposure which was followed by 37% recovery in males and 100% recovery in females, 1 week later. These results indicate that sarin induces a long-term decreased affinity in M2 mAChR (elevated KDs) and a transient effect on the number of this receptor subtype (Bmax). We hypothesize that the reduced affinity of the M2 receptors (negative auto-regulatory receptors) may cause long-term brain deficits by impairing the normal regulation release of ACh into the synaptic cleft.
Collapse
|
13
|
Lu B, Chen L, Zhang Y, Shi Y, Zhou N. Quantitative analysis of G-protein-coupled receptor internalization using DnaE intein-based assay. Methods Cell Biol 2016; 132:293-318. [PMID: 26928549 DOI: 10.1016/bs.mcb.2015.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
G-protein-coupled receptors (GPCRs), the largest family of cell surface receptors, are involved in many physiological processes. They represent highly important therapeutic targets for drug discovery. Currently, there are numerous cell-based assays developed for the pharmacological profiling of GPCRs and the identification of novel agonists and antagonists. However, the development of new, faster, easier, and more cost-effective approaches to detect GPCR activity remains highly desirable. β-arrestin-dependent internalization has been demonstrated to be a common mechanism for most GPCRs. Here we describe a novel assay for quantitative analysis of GPCR internalization based on DnaE intein-mediated reconstitution of fragmented Renilla luciferase or Firefly luciferase when activated GPCRs interact with β-arrestin2 or Rab5. Further validation, using functionally divergent GPCRs, showed that EC50 values obtained for the known agonists and antagonists were in close agreement with the results of previous reports. This suggests that this assay is sensitive enough to permit quantification of GPCR internalization. Compared with conventional assays, this novel assay system is cost-effective, rapid, and easy to manipulate. These advantages may allow this assay to be used universally as a functional cell-based system for GPCR characterization and in the screening process of drug discovery.
Collapse
Affiliation(s)
- Bin Lu
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang, China
| | - Linjie Chen
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yaping Zhang
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ying Shi
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang, China
| | - Naiming Zhou
- Institute of Biochemistry, College of Life Sciences, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang, China
| |
Collapse
|