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Gutierrez-Castañeda NE, Martínez-Rojas VA, Ochoa-de la Paz LD, Galván EJ. The bidirectional role of GABAA and GABAB receptors during the differentiation process of neural precursor cells of the subventricular zone. PLoS One 2024; 19:e0305853. [PMID: 38913632 PMCID: PMC11195948 DOI: 10.1371/journal.pone.0305853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 06/05/2024] [Indexed: 06/26/2024] Open
Abstract
The intricate process of neuronal differentiation integrates multiple signals to induce transcriptional, morphological, and electrophysiological changes that reshape the properties of neural precursor cells during their maturation and migration process. An increasing number of neurotransmitters and biomolecules have been identified as molecular signals that trigger and guide this process. In this sense, taurine, a sulfur-containing, non-essential amino acid widely expressed in the mammal brain, modulates the neuronal differentiation process. In this study, we describe the effect of taurine acting via the ionotropic GABAA receptor and the metabotropic GABAB receptor on the neuronal differentiation and electrophysiological properties of precursor cells derived from the subventricular zone of the mouse brain. Taurine stimulates the number of neurites and favors the dendritic complexity of the neural precursor cells, accompanied by changes in the somatic input resistance and the strength of inward and outward membranal currents. At the pharmacological level, the blockade of GABAA receptors inhibits these effects, whereas the stimulation of GABAB receptors has no positive effects on the taurine-mediated differentiation process. Strikingly, the blockade of the GABAB receptor with CGP533737 stimulates neurite outgrowth, dendritic complexity, and membranal current kinetics of neural precursor cells. The effects of taurine on the differentiation process involve Ca2+ mobilization and the activation of intracellular signaling cascades since chelation of intracellular calcium with BAPTA-AM, and inhibition of the CaMKII, ERK1/2, and Src kinase inhibits the neurite outgrowth of neural precursor cells of the subventricular zone.
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Affiliation(s)
- Nadia Estefanía Gutierrez-Castañeda
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, México
| | - Vladimir Allex Martínez-Rojas
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, México
| | - Lenin David Ochoa-de la Paz
- Laboratorio de Neurobiología Molecular y Celular de la Glía, Unidad de Investigación UNAM-APEC, México City, México
| | - Emilio J. Galván
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, México
- Centro de Investigación sobre el Envejecimiento, Ciudad de México, México
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Wei R, Li D, Jia S, Chen Y, Wang J. MC4R in Central and Peripheral Systems. Adv Biol (Weinh) 2023; 7:e2300035. [PMID: 37043700 DOI: 10.1002/adbi.202300035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 02/25/2023] [Indexed: 04/14/2023]
Abstract
Obesity has emerged as a critical and urgent health burden during the current global pandemic. Among multiple genetic causes, melanocortin receptor-4 (MC4R), involved in food intake and energy metabolism regulation through various signaling pathways, has been reported to be the lead genetic factor in severe and early onset obesity and hyperphagia disorders. Most previous studies have illustrated the roles of MC4R signaling in energy intake versus expenditure in the central system, while some evidence indicates that MC4R is also expressed in peripheral systems, such as the gut and endocrine organs. However, its physiopathological function remains poorly defined. This review aims to depict the central and peripheral roles of MC4R in energy metabolism and endocrine hormone homeostasis, the diversity of phenotypes, biased downstream signaling caused by distinct MC4R mutations, and current drug development targeting the receptor.
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Affiliation(s)
- Ran Wei
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
- Department of Endocrinology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, 200240, China
| | - Danjie Li
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Sheng Jia
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Yuhong Chen
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Jiqiu Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
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McCarthy CI, Mustafá ER, Cornejo MP, Yaneff A, Rodríguez SS, Perello M, Raingo J. Chlorpromazine, an Inverse Agonist of D1R-Like, Differentially Targets Voltage-Gated Calcium Channel (Ca V) Subtypes in mPFC Neurons. Mol Neurobiol 2023; 60:2644-2660. [PMID: 36694048 DOI: 10.1007/s12035-023-03221-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 01/04/2023] [Indexed: 01/26/2023]
Abstract
The dopamine receptor type 1 (D1R) and the dopamine receptor type 5 (D5R), which are often grouped as D1R-like due to their sequence and signaling similarities, exhibit high levels of constitutive activity. The molecular basis for this agonist-independent activation has been well characterized through biochemical and mutagenesis in vitro studies. In this regard, it was reported that many antipsychotic drugs act as inverse agonists of D1R-like constitutive activity. On the other hand, D1R is highly expressed in the medial prefrontal cortex (mPFC), a brain area with important functions such as working memory. Here, we studied the impact of D1R-like constitutive activity and chlorpromazine (CPZ), an antipsychotic drug and D1R-like inverse agonist, on various neuronal CaV conductances, and we explored its effect on calcium-dependent neuronal functions in the mouse medial mPFC. Using ex vivo brain slices containing the mPFC and transfected HEK293T cells, we found that CPZ reduces CaV2.2 currents by occluding D1R-like constitutive activity, in agreement with a mechanism previously reported by our lab, whereas CPZ directly inhibits CaV1 currents in a D1R-like activity independent manner. In contrast, CPZ and D1R constitutive activity did not affect CaV2.1, CaV2.3, or CaV3 currents. Finally, we found that CPZ reduces excitatory postsynaptic responses in mPFC neurons. Our results contribute to understanding CPZ molecular targets in neurons and describe a novel physiological consequence of CPZ non-canonical action as a D1R-like inverse agonist in the mouse brain.
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Affiliation(s)
- Clara Inés McCarthy
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology (Argentine Research Council CONICET, Scientific Research Commission of the Buenos Aires Province and National University of La Plata), La Plata, Buenos Aires, Argentina
| | - Emilio Román Mustafá
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology (Argentine Research Council CONICET, Scientific Research Commission of the Buenos Aires Province and National University of La Plata), La Plata, Buenos Aires, Argentina
| | - María Paula Cornejo
- Neurophysiology Laboratory of the Multidisciplinary Institute of Cell Biology (Argentine Research Council CONICET, Scientific Research Commission of the Buenos Aires Province and National University of La Plata), La Plata, Buenos Aires, Argentina
| | - Agustín Yaneff
- Instituto de Investigaciones Farmacológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Silvia Susana Rodríguez
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology (Argentine Research Council CONICET, Scientific Research Commission of the Buenos Aires Province and National University of La Plata), La Plata, Buenos Aires, Argentina
| | - Mario Perello
- Neurophysiology Laboratory of the Multidisciplinary Institute of Cell Biology (Argentine Research Council CONICET, Scientific Research Commission of the Buenos Aires Province and National University of La Plata), La Plata, Buenos Aires, Argentina
- Department of Surgical Sciences, Functional Pharmacology and Neuroscience, University of Uppsala, Uppsala, Sweden
| | - Jesica Raingo
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology (Argentine Research Council CONICET, Scientific Research Commission of the Buenos Aires Province and National University of La Plata), La Plata, Buenos Aires, Argentina.
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Fernández E, McCarthy CI, Cerviño RH, Rodríguez SS, Yaneff A, Hernández J, Garrido V, Di Rocco F, Raingo J. Functional alterations of two novel MC4R mutations found in Argentinian pediatric patients with early onset obesity. Mol Cell Endocrinol 2023; 559:111777. [PMID: 36210601 DOI: 10.1016/j.mce.2022.111777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 02/03/2023]
Abstract
Loss-of-function mutations in melanocortin-4 receptor (MC4R) are the most common cause of monogenic obesity, a severe type of early-onset obesity. Our aim was to determine the prevalence of MC4R mutations in a cohort of 97 Argentinian children with early-onset obesity. We found two novel mutations (p.V52E and p.G233S) and estimated a prevalence of 2.1%. We investigated the pathogenicity of mutations in HEK293T cells expressing wild-type or mutant MC4R and found that both mutants exhibited reduced plasma membrane expression and altered agonist-induced cAMP responses, with no changes in basal activity. Besides, MC4R G233S mutant demonstrated an altered agonist-dependent inhibition of voltage-gated calcium channels type 2.2. Results using a Gαs protein inhibitor suggest that the G233S mutation could be recruiting a different G-protein signaling pathway. The identification of new mutations in MC4R and characterization of their functional impact provide tools for the diagnosis and treatment of monogenic obesity.
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Affiliation(s)
- Estefanía Fernández
- Laboratorio de Genética Molecular, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de La Plata (UNLP) y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina.
| | - Clara Inés McCarthy
- Laboratorio de Electrofisiología, IMBICE, CONICET, UNLP y CIC-PBA, La Plata, Buenos Aires, Argentina.
| | - Ramiro Hector Cerviño
- Instituto de Investigaciones Farmacológicas (ININFA, UBA, CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.
| | - Silvia Susana Rodríguez
- Laboratorio de Electrofisiología, IMBICE, CONICET, UNLP y CIC-PBA, La Plata, Buenos Aires, Argentina.
| | - Agustín Yaneff
- Instituto de Investigaciones Farmacológicas (ININFA, UBA, CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.
| | - Julieta Hernández
- Servicio de Nutrición del Hospital de Niños "Sor María Ludovica" de La Plata, La Plata, Buenos Aires, Argentina.
| | - Verónica Garrido
- Servicio de Nutrición del Hospital de Niños "Sor María Ludovica" de La Plata, La Plata, Buenos Aires, Argentina.
| | - Florencia Di Rocco
- Laboratorio de Genética Molecular, Instituto Multidisciplinario de Biología Celular (IMBICE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de La Plata (UNLP) y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina.
| | - Jesica Raingo
- Laboratorio de Electrofisiología, IMBICE, CONICET, UNLP y CIC-PBA, La Plata, Buenos Aires, Argentina.
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Mustafá ER, McCarthy CI, Portales AE, Cordisco Gonzalez S, Rodríguez SS, Raingo J. Constitutive activity of the dopamine (D 5 ) receptor, highly expressed in CA1 hippocampal neurons, selectively reduces Ca V 3.2 and Ca V 3.3 currents. Br J Pharmacol 2022; 180:1210-1231. [PMID: 36480023 DOI: 10.1111/bph.16006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 10/31/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE CaV 3.1-3 currents differentially contribute to neuronal firing patterns. CaV 3 are regulated by G protein-coupled receptors (GPCRs) activity, but information about CaV 3 as targets of the constitutive activity of GPCRs is scarce. We investigate the impact of D5 recpetor constitutive activity, a GPCR with high levels of basal activity, on CaV 3 functionality. D5 recpetor and CaV 3 are expressed in the hippocampus and have been independently linked to pathophysiological states associated with epilepsy. EXPERIMENTAL APPROACH Our study models were HEK293T cells heterologously expressing D1 or D5 receptor and CaV 3.1-3, and mouse brain slices containing the hippocampus. We used chlorpromazine (D1 /D5 inverse agonist) and a D5 receptor mutant lacking constitutive activity as experimental tools. We measured CaV 3 currents and excitability parameters using the patch-clamp technique. We completed our study with computational modelling and imaging technique. KEY RESULTS We found a higher sensitivity to TTA-P2 (CaV 3 blocker) in CA1 pyramidal neurons obtained from chlorpromazine-treated animals compared with vehicle-treated animals. We found that CaV 3.2 and CaV 3.3-but not CaV 3.1-are targets of D5 receptor constitutive activity in HEK293T cells. Finally, we found an increased firing rate in CA1 pyramidal neurons from chlorpromazine-treated animals in comparison with vehicle-treated animals. Similar changes in firing rate were observed on a neuronal model with controlled CaV 3 currents levels. CONCLUSIONS AND IMPLICATIONS Native hippocampal CaV 3 and recombinant CaV 3.2-3 are sensitive to D5 receptor constitutive activity. Manipulation of D5 receptor constitutive activity could be a valuable strategy to control neuronal excitability, especially in exacerbated conditions such as epilepsy.
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Affiliation(s)
- Emilio Román Mustafá
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
| | - Clara Inés McCarthy
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
| | - Andrea Estefanía Portales
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
| | - Santiago Cordisco Gonzalez
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
| | - Silvia Susana Rodríguez
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
| | - Jesica Raingo
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
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Zeng S, Zhu R, Wang Y, Yang Y, Li N, Fu N, Sun M, Zhang J. Role of GABA A receptor depolarization-mediated VGCC activation in sevoflurane-induced cognitive impairment in neonatal mice. Front Cell Neurosci 2022; 16:964227. [PMID: 36176629 PMCID: PMC9514857 DOI: 10.3389/fncel.2022.964227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
Background In neonatal mice, anesthesia with sevoflurane depolarizes the GABA Type A receptor (GABAAR), which leads to cognitive impairment. Calcium accumulation in neurons can lead to neurotoxicity. Voltage-gated calcium channels (VGCCs) can increase intracellular calcium concentration under isoflurane and hypoxic conditions. The underlying mechanisms remain largely unknown. Methods Six-day-old mice were anesthetized with 3% sevoflurane for 2 h/day for 3 days. The Y-Maze, new object recognition (NOR) test, the Barnes maze test, immunoassay, immunoblotting, the TUNEL test, and Golgi-Cox staining were used to assess cognition, calcium concentration, inflammatory response, GABAAR activation, VGCC expression, apoptosis, and proliferation of hippocampal nerve cells in mice and HT22 cells. Results Compared with the control group, mice in the sevoflurane group had impaired cognitive function. In the sevoflurane group, the expression of Gabrb3 and Cav1.2 in the hippocampal neurons increased (p < 0.01), the concentration of calcium ions increased (p < 0.01), inflammatory reaction and apoptosis of neurons increased (p < 0.01), the proliferation of neurons in the DG area decreased (p < 0.01), and dendritic spine density decreased (p < 0.05). However, the inhibition of Gabrb3 and Cav1.2 alleviated cognitive impairment and reduced neurotoxicity. Conclusions Sevoflurane activates VGCCs by inducing GABAAR depolarization, resulting in cognitive impairment. Activated VGCCs cause an increase in intracellular calcium concentration and an inflammatory response, resulting in neurotoxicity and cognitive impairment.
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Affiliation(s)
- Shuang Zeng
- Department of Anesthesiology and Perioperative Medicine, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Ruilou Zhu
- Department of Anesthesiology and Perioperative Medicine, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Yangyang Wang
- Department of Anesthesiology and Perioperative Medicine, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Yitian Yang
- Department of Anesthesiology and Perioperative Medicine, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Ningning Li
- Department of Anesthesiology and Perioperative Medicine, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Ningning Fu
- Department of Anesthesiology and Perioperative Medicine, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Mingyang Sun
- Department of Anesthesiology and Perioperative Medicine, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Jiaqiang Zhang
- Department of Anesthesiology and Perioperative Medicine, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
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McCarthy CI, Chou-Freed C, Rodríguez SS, Yaneff A, Davio C, Raingo J. Constitutive activity of dopamine receptor type 1 (D1R) increases CaV2.2 currents in PFC neurons. J Gen Physiol 2021; 152:151624. [PMID: 32259196 PMCID: PMC7201881 DOI: 10.1085/jgp.201912492] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 02/14/2020] [Accepted: 03/12/2020] [Indexed: 01/19/2023] Open
Abstract
Alterations in dopamine receptor type 1 (D1R) density are associated with cognitive deficits of aging and schizophrenia. In the prefrontal cortex (PFC), D1R plays a critical role in the regulation of working memory, which is impaired in these cognitive deficit states, but the cellular events triggered by changes in D1R expression remain unknown. A previous report demonstrated that interaction between voltage-gated calcium channel type 2.2 (CaV2.2) and D1R stimulates CaV2.2 postsynaptic surface location in medial PFC pyramidal neurons. Here, we show that in addition to the occurrence of the physical receptor-channel interaction, constitutive D1R activity mediates up-regulation of functional CaV2.2 surface density. We performed patch-clamp experiments on transfected HEK293T cells and wild-type C57BL/6 mouse brain slices, as well as imaging experiments and cAMP measurements. We found that D1R coexpression led to ∼60% increase in CaV2.2 currents in HEK293T cells. This effect was occluded by preincubation with a D1/D5R inverse agonist, chlorpromazine, and by replacing D1R with a D1R mutant lacking constitutive activity. Moreover, D1R-induced increase in CaV2.2 currents required basally active Gs protein, as well as D1R-CaV2.2 interaction. In mice, intraperitoneal administration of chlorpromazine reduced native CaV currents’ sensitivity to ω-conotoxin-GVIA and their size by ∼49% in layer V/VI pyramidal neurons from medial PFC, indicating a selective effect on CaV2.2. Additionally, we found that reducing D1/D5R constitutive activity correlates with a decrease in the agonist-induced D1/D5R inhibitory effect on native CaV currents. Our results could be interpreted as a stimulatory effect of D1R constitutive activity on the number of CaV2.2 channels available for dopamine-mediated modulation. Our results contribute to the understanding of the physiological role of D1R constitutive activity and may explain the noncanonical postsynaptic distribution of functional CaV2.2 in PFC neurons.
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Affiliation(s)
- Clara Inés McCarthy
- Electrophysiology Laboratory, Multidisciplinary Institute of Cell Biology, Universidad Nacional de La Plata, Consejo de Investigaciones Científicas y Técnicas, Comisión de Investigaciones de la Provincia de Buenos Aires, Buenos Aires, Argentina
| | - Cambria Chou-Freed
- Electrophysiology Laboratory, Multidisciplinary Institute of Cell Biology, Universidad Nacional de La Plata, Consejo de Investigaciones Científicas y Técnicas, Comisión de Investigaciones de la Provincia de Buenos Aires, Buenos Aires, Argentina
| | - Silvia Susana Rodríguez
- Electrophysiology Laboratory, Multidisciplinary Institute of Cell Biology, Universidad Nacional de La Plata, Consejo de Investigaciones Científicas y Técnicas, Comisión de Investigaciones de la Provincia de Buenos Aires, Buenos Aires, Argentina
| | - Agustín Yaneff
- Instituto de Investigaciones Farmacológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Carlos Davio
- Instituto de Investigaciones Farmacológicas, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Jesica Raingo
- Electrophysiology Laboratory, Multidisciplinary Institute of Cell Biology, Universidad Nacional de La Plata, Consejo de Investigaciones Científicas y Técnicas, Comisión de Investigaciones de la Provincia de Buenos Aires, Buenos Aires, Argentina
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Yeo GSH, Chao DHM, Siegert AM, Koerperich ZM, Ericson MD, Simonds SE, Larson CM, Luquet S, Clarke I, Sharma S, Clément K, Cowley MA, Haskell-Luevano C, Van Der Ploeg L, Adan RAH. The melanocortin pathway and energy homeostasis: From discovery to obesity therapy. Mol Metab 2021; 48:101206. [PMID: 33684608 PMCID: PMC8050006 DOI: 10.1016/j.molmet.2021.101206] [Citation(s) in RCA: 98] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 02/28/2021] [Accepted: 03/03/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Over the past 20 years, insights from human and mouse genetics have illuminated the central role of the brain leptin-melanocortin pathway in controlling mammalian food intake, with genetic disruption resulting in extreme obesity, and more subtle polymorphic variations influencing the population distribution of body weight. At the end of 2020, the U.S. Food and Drug Administration (FDA) approved setmelanotide, a melanocortin 4 receptor agonist, for use in individuals with severe obesity due to either pro-opiomelanocortin (POMC), proprotein convertase subtilisin/kexin type 1 (PCSK1), or leptin receptor (LEPR) deficiency. SCOPE OF REVIEW Herein, we chart the melanocortin pathway's history, explore its pharmacology, genetics, and physiology, and describe how a neuropeptidergic circuit became an important druggable obesity target. MAJOR CONCLUSIONS Unravelling the genetics of the subset of severe obesity has revealed the importance of the melanocortin pathway in appetitive control; coupling this with studying the molecular pharmacology of compounds that bind melanocortin receptors has brought a new obesity drug to the market. This process provides a drug discovery template for complex disorders, which for setmelanotide took 25 years to transform from a single gene into an approved drug.
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Affiliation(s)
- Giles S H Yeo
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | | | - Anna-Maria Siegert
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
| | - Zoe M Koerperich
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA 55455.
| | - Mark D Ericson
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA 55455.
| | - Stephanie E Simonds
- Metabolism, Diabetes, and Obesity Programme, Monash Biomedicine Discovery Institute, and Department of Physiology, Monash University, Clayton, Victoria, Australia.
| | - Courtney M Larson
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA 55455.
| | - Serge Luquet
- Université de Paris, BFA, UMR 8251, CNRS, Paris, France.
| | - Iain Clarke
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC 3010, Australia.
| | | | - Karine Clément
- Assistance Publique Hôpitaux de Paris, Nutrition Department, Pitié-Salpêtrière Hospital, Paris, France, Sorbonne Université, INSERM, Nutrition and Obesity: Systemic Approaches (NutriOmics) Research Unit, Paris, France.
| | - Michael A Cowley
- Metabolism, Diabetes, and Obesity Programme, Monash Biomedicine Discovery Institute, and Department of Physiology, Monash University, Clayton, Victoria, Australia.
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA 55455.
| | | | - Roger A H Adan
- Department of Translational Neuroscience, UMCU Brain Centre, University Medical Centre Utrecht, Utrecht University, the Netherlands; Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Sweden.
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Rojo D, McCarthy C, Raingo J, Rubinstein M. Mouse models for V103I and I251L gain of function variants of the human MC4R display decreased adiposity but are not protected against a hypercaloric diet. Mol Metab 2020; 42:101077. [PMID: 32916307 PMCID: PMC7559519 DOI: 10.1016/j.molmet.2020.101077] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/20/2020] [Accepted: 09/06/2020] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE The melanocortin 4 receptor (MC4R) is a G protein-coupled receptor that plays major roles in the central control of energy balance. Loss-of-function mutations of MC4R constitute the most common monogenic cause of early-onset extreme obesity in humans, whereas gain-of-function mutations appear to be protective. In particular, two relatively frequent alleles carrying the non-synonymous coding mutations V103I or I251L are associated with lower risks of obesity and type-2 diabetes. Although V103I and I251L MC4Rs showed more efficient signalling in transfected cells, their specific effects in live animals remain unexplored. Here, we investigated whether the introduction of V103I and I251L mutations into the mouse MC4R leads to a lean phenotype and provides protection against an obesogenic diet. METHODS Using CRISPR/Cas9, we generated two novel strains of mice carrying single-nucleotide mutations into the mouse Mc4r which are identical to those present in V103I and I251L MCR4 human alleles, and studied their phenotypic outcomes in mice fed with normal chow or a high-fat diet. In particular, we measured body weight progression, food intake and adiposity. In addition, we analysed glucose homeostasis through glucose and insulin tolerance tests. RESULTS We found that homozygous V103I females displayed shorter longitudinal length and decreased abdominal white fat, whereas homozygous I251L females were also shorter and leaner due to decreased weight in all white fat pads examined. Homozygous Mc4rV103I/V103I and Mc4rI251L/I251L mice of both sexes showed improved glucose homeostasis when challenged in a glucose tolerance test, whereas Mc4rI251L/I251L females showed improved responses to insulin. Despite being leaner and metabolically more efficient, V103I and I251L mutants fed with a hypercaloric diet increased their fasting glucose levels and adiposity similar to their wild-type littermates. CONCLUSIONS Our results demonstrate that mice carrying V103I and I251L MC4R mutations displayed gain-of-function phenotypes that were more evident in females. However, hypermorphic MC4R mutants were as susceptible as their control littermates to the obesogenic and diabetogenic effects elicited by a long-term hypercaloric diet, highlighting the importance of healthy feeding habits even under favourable genetic conditions.
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Affiliation(s)
- Daniela Rojo
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires, Argentina
| | - Clara McCarthy
- Instituto Multidisciplinario de Biología Celular, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de La Plata and Comisión de Investigaciones de la Provincia de Buenos Aires, La Plata, Province of Buenos Aires, Argentina
| | - Jesica Raingo
- Instituto Multidisciplinario de Biología Celular, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de La Plata and Comisión de Investigaciones de la Provincia de Buenos Aires, La Plata, Province of Buenos Aires, Argentina
| | - Marcelo Rubinstein
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires, Argentina; Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48105, USA.
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Yang LK, Tao YX. Alanine Scanning Mutagenesis of the DRYxxI Motif and Intracellular Loop 2 of Human Melanocortin-4 Receptor. Int J Mol Sci 2020; 21:ijms21207611. [PMID: 33076233 PMCID: PMC7589821 DOI: 10.3390/ijms21207611] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/10/2020] [Accepted: 10/11/2020] [Indexed: 12/15/2022] Open
Abstract
The melanocortin-4 receptor (MC4R) is a member of the G-protein-coupled receptor (GPCR) superfamily, which has been extensively studied in obesity pathogenesis due to its critical role in regulating energy homeostasis. Both the Gs-cAMP and ERK1/2 cascades are known as important intracellular signaling pathways initiated by the MC4R. The DRYxxI motif at the end of transmembrane domain 3 and the intracellular loop 2 (ICL2) are thought to be crucial for receptor function in several GPCRs. To study the functions of this domain in MC4R, we performed alanine-scanning mutagenesis on seventeen residues. We showed that one residue was critical for receptor cell surface expression. Eight residues were important for ligand binding. Mutations of three residues impaired Gs-cAMP signaling without changing the binding properties. Investigation on constitutive activities of all the mutants in the cAMP pathway revealed that six residues were involved in constraining the receptor in inactive states and five residues were important for receptor activation in the absence of an agonist. In addition, mutations of four residues impaired the ligand-stimulated ERK1/2 signaling pathway without affecting the binding properties. We also showed that some mutants were biased to the Gs-cAMP or ERK1/2 signaling pathway. In summary, we demonstrated that the DRYxxI motif and ICL2 were important for MC4R function.
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Structural Complexity and Plasticity of Signaling Regulation at the Melanocortin-4 Receptor. Int J Mol Sci 2020; 21:ijms21165728. [PMID: 32785054 PMCID: PMC7460885 DOI: 10.3390/ijms21165728] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/03/2020] [Accepted: 08/06/2020] [Indexed: 02/06/2023] Open
Abstract
The melanocortin-4 receptor (MC4R) is a class A G protein-coupled receptor (GPCR), essential for regulation of appetite and metabolism. Pathogenic inactivating MC4R mutations are the most frequent cause of monogenic obesity, a growing medical and socioeconomic problem worldwide. The MC4R mediates either ligand-independent or ligand-dependent signaling. Agonists such as α-melanocyte-stimulating hormone (α-MSH) induce anorexigenic effects, in contrast to the endogenous inverse agonist agouti-related peptide (AgRP), which causes orexigenic effects by suppressing high basal signaling activity. Agonist action triggers the binding of different subtypes of G proteins and arrestins, leading to concomitant induction of diverse intracellular signaling cascades. An increasing number of experimental studies have unraveled molecular properties and mechanisms of MC4R signal transduction related to physiological and pathophysiological aspects. In addition, the MC4R crystal structure was recently determined at 2.75 Å resolution in an inactive state bound with a peptide antagonist. Underpinned by structural homology models of MC4R complexes simulating a presumably active-state conformation compared to the structure of the inactive state, we here briefly summarize the current understanding and key players involved in the MC4R switching process between different activity states. Finally, these perspectives highlight the complexity and plasticity in MC4R signaling regulation and identify gaps in our current knowledge.
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12
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Cordisco Gonzalez S, Mustafá ER, Rodriguez SS, Perello M, Raingo J. Dopamine Receptor Type 2 and Ghrelin Receptor Coexpression Alters Ca V2.2 Modulation by G Protein Signaling Cascades. ACS Chem Neurosci 2020; 11:3-13. [PMID: 31808667 DOI: 10.1021/acschemneuro.9b00426] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Voltage-gated calcium channels type 2.2 (CaV2.2) are activated by action potentials at presynaptic terminals, and their calcium current induces neurotransmitter release. In this context, regulating CaV2.2 is critical, and one of the most important mechanisms for doing so is through its G protein-coupled receptor (GPCR) activity. Two such GPCRs are the ghrelin (GHSR) and the dopamine type 2 (D2R) receptors. We previously demonstrated that constitutive GHSR activity reduces CaV2.2 forward trafficking and that ghrelin-induced GHSR activity inhibits CaV2.2 currents. On the other hand, dopamine-induced D2R activity also inhibits CaV2.2 currents. It has been recently shown that D2R and GHSR form heteromers in hypothalamic neurons. This interaction profoundly changes the signaling cascades activated by dopamine and is necessary for dopamine-dependent anorexia. Here we explored how D2R-GHSR coexpression in HEK293T cells modulates the effect that each GPCR has on CaV2.2. We found that D2R-GHSR coexpression reduces the inhibition of CaV2.2 currents by agonist-induced D2R activation and added a new source of basal CaV2.2 current inhibition to the one produced by GHSR solely expression. We investigated the signaling cascades implicated and found that constitutive GHSR activity, Gq protein, and Gβγ subunit play a critical role in these altered effects. Moreover, we found that the effect of D2R agonist on native calcium currents in hypothalamic neurons is reduced when both D2R and GHSR are overexpressed. In summary, our results allow us to propose a novel mechanism for controlling CaV2.2 currents involving the coexpression of two physiologically relevant GPCRs.
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de Hoog E, Lukewich MK, Spencer GE. Retinoid receptor-based signaling plays a role in voltage-dependent inhibition of invertebrate voltage-gated Ca 2+ channels. J Biol Chem 2019; 294:10076-10093. [PMID: 31048374 DOI: 10.1074/jbc.ra118.006444] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 04/30/2019] [Indexed: 01/04/2023] Open
Abstract
The retinoic acid receptor (RAR) and retinoid X receptor (RXR) mediate the cellular effects of retinoids (derivatives of vitamin A). Both RAR and RXR signaling events are implicated in hippocampal synaptic plasticity. Furthermore, retinoids can interact with calcium signaling during homeostatic plasticity. We recently provided evidence that retinoids attenuate calcium current (I Ca) through neuronal voltage-gated calcium channels (VGCCs). We now examined the possibility that constitutive activity of neuronal RXR and/or RAR alters calcium influx via the VGCCs. We found that in neurons of the mollusk Lymnaea stagnalis, two different RXR antagonists (PA452 and HX531) had independent and opposing effects on I Ca that were also time-dependent; whereas the RXR pan-antagonist PA452 enhanced I Ca, HX531 reduced I Ca Interestingly, this effect of HX531 occurred through voltage-dependent inhibition of VGCCs, a phenomenon known to influence neurotransmitter release from neurons. This inhibition appeared to be independent of G proteins and was largely restricted to Cav2 Ca2+ channels. Of note, an RAR pan-antagonist, LE540, also inhibited I Ca but produced G protein-dependent, voltage-dependent inhibition of VGCCs. These findings provide evidence that retinoid receptors interact with G proteins in neurons and suggest mechanisms by which retinoids might affect synaptic calcium signaling.
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Affiliation(s)
- Eric de Hoog
- From the Department of Biological Sciences, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - Mark K Lukewich
- From the Department of Biological Sciences, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - Gaynor E Spencer
- From the Department of Biological Sciences, Brock University, St. Catharines, Ontario L2S 3A1, Canada
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14
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Baldini G, Phelan KD. The melanocortin pathway and control of appetite-progress and therapeutic implications. J Endocrinol 2019; 241:R1-R33. [PMID: 30812013 PMCID: PMC6500576 DOI: 10.1530/joe-18-0596] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 01/22/2019] [Indexed: 12/19/2022]
Abstract
The initial discovery that ob/ob mice become obese because of a recessive mutation of the leptin gene has been crucial to discover the melanocortin pathway to control appetite. In the melanocortin pathway, the fed state is signaled by abundance of circulating hormones such as leptin and insulin, which bind to receptors expressed at the surface of pro-opiomelanocortin (POMC) neurons to promote processing of POMC to the mature hormone α-melanocyte-stimulating hormone (α-MSH). The α-MSH released by POMC neurons then signals to decrease energy intake by binding to melanocortin-4 receptor (MC4R) expressed by MC4R neurons to the paraventricular nucleus (PVN). Conversely, in the 'starved state' activity of agouti-related neuropeptide (AgRP) and of neuropeptide Y (NPY)-expressing neurons is increased by decreased levels of circulating leptin and insulin and by the orexigenic hormone ghrelin to promote food intake. This initial understanding of the melanocortin pathway has recently been implemented by the description of the complex neuronal circuit that controls the activity of POMC, AgRP/NPY and MC4R neurons and downstream signaling by these neurons. This review summarizes the progress done on the melanocortin pathway and describes how obesity alters this pathway to disrupt energy homeostasis. We also describe progress on how leptin and insulin receptors signal in POMC neurons, how MC4R signals and how altered expression and traffic of MC4R change the acute signaling and desensitization properties of the receptor. We also describe how the discovery of the melanocortin pathway has led to the use of melanocortin agonists to treat obesity derived from genetic disorders.
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Affiliation(s)
- Giulia Baldini
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Kevin D. Phelan
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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15
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Zhang Y, Jiang D, Li H, Sun Y, Jiang X, Gong S, Qian Z, Tao J. Melanocortin type 4 receptor-mediated inhibition of A-type K + current enhances sensory neuronal excitability and mechanical pain sensitivity in rats. J Biol Chem 2019; 294:5496-5507. [PMID: 30745360 DOI: 10.1074/jbc.ra118.006894] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/07/2019] [Indexed: 12/28/2022] Open
Abstract
α-Melanocyte-stimulating hormone (α-MSH) has been shown to be involved in nociception, but the underlying molecular mechanisms remain largely unknown. In this study, we report that α-MSH suppresses the transient outward A-type K+ current (I A) in trigeminal ganglion (TG) neurons and thereby modulates neuronal excitability and peripheral pain sensitivity in rats. Exposing small-diameter TG neurons to α-MSH concentration-dependently decreased I A This α-MSH-induced I A decrease was dependent on the melanocortin type 4 receptor (MC4R) and associated with a hyperpolarizing shift in the voltage dependence of A-type K+ channel inactivation. Chemical inhibition of phosphatidylinositol 3-kinase (PI3K) with wortmannin or of class I PI3Ks with the selective inhibitor CH5132799 prevented the MC4R-mediated I A response. Blocking Gi/o-protein signaling with pertussis toxin or by dialysis of TG neurons with the Gβγ-blocking synthetic peptide QEHA abolished the α-MSH-mediated decrease in I A Further, α-MSH increased the expression levels of phospho-p38 mitogen-activated protein kinase, and pharmacological or genetic inhibition of p38α abrogated the α-MSH-induced I A response. Additionally, α-MSH significantly increased the action potential firing rate of TG neurons and increased the sensitivity of rats to mechanical stimuli applied to the buccal pad area, and both effects were abrogated by I A blockade. Taken together, our findings suggest that α-MSH suppresses I A by activating MC4R, which is coupled sequentially to the Gβγ complex of the Gi/o-protein and downstream class I PI3K-dependent p38α signaling, thereby increasing TG neuronal excitability and mechanical pain sensitivity in rats.
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Affiliation(s)
- Yuan Zhang
- From the Department of Geriatrics, the Second Affiliated Hospital of Soochow University, Suzhou 215004, China.,the Department of Physiology and Neurobiology and Centre for Ion Channelopathy, Medical College of Soochow University, Suzhou 215123, China
| | - Dongsheng Jiang
- the Department of Physiology and Neurobiology and Centre for Ion Channelopathy, Medical College of Soochow University, Suzhou 215123, China.,the Comprehensive Pneumology Center, Helmholtz Zentrum München, Munich 81377, Germany, and
| | - Hua Li
- the National Shanghai Center for New Drug Safety Evaluation and Research, Shanghai 201203, China
| | - Yufang Sun
- the Department of Physiology and Neurobiology and Centre for Ion Channelopathy, Medical College of Soochow University, Suzhou 215123, China
| | - Xinghong Jiang
- the Department of Physiology and Neurobiology and Centre for Ion Channelopathy, Medical College of Soochow University, Suzhou 215123, China
| | - Shan Gong
- the Department of Physiology and Neurobiology and Centre for Ion Channelopathy, Medical College of Soochow University, Suzhou 215123, China
| | - Zhiyuan Qian
- From the Department of Geriatrics, the Second Affiliated Hospital of Soochow University, Suzhou 215004, China,
| | - Jin Tao
- the Department of Physiology and Neurobiology and Centre for Ion Channelopathy, Medical College of Soochow University, Suzhou 215123, China, .,the Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou 215123, China
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Heyder N, Kleinau G, Szczepek M, Kwiatkowski D, Speck D, Soletto L, Cerdá-Reverter JM, Krude H, Kühnen P, Biebermann H, Scheerer P. Signal Transduction and Pathogenic Modifications at the Melanocortin-4 Receptor: A Structural Perspective. Front Endocrinol (Lausanne) 2019; 10:515. [PMID: 31417496 PMCID: PMC6685040 DOI: 10.3389/fendo.2019.00515] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 07/15/2019] [Indexed: 12/19/2022] Open
Abstract
The melanocortin-4 receptor (MC4R) can be endogenously activated by binding of melanocyte-stimulating hormones (MSH), which mediates anorexigenic effects. In contrast, the agouti-related peptide (AgRP) acts as an endogenous inverse agonist and suppresses ligand-independent basal signaling activity (orexigenic effects). Binding of ligands to MC4R leads to the activation of different G-protein subtypes or arrestin and concomitant signaling pathways. This receptor is a key protein in the hypothalamic regulation of food intake and energy expenditure and naturally-occurring inactivating MC4R variants are the most frequent cause of monogenic obesity. In general, obesity is a growing problem on a global scale and is of social, medical, and economic relevance. A significant goal is to develop optimized pharmacological tools targeting MC4R without adverse effects. To date, this has not been achieved because of inter alia non-selective ligands across the five functionally different MCR subtypes (MC1-5R). This motivates further investigation of (i) the three-dimensional MC4R structure, (ii) binding mechanisms of various ligands, and (iii) the molecular transfer process of signal transduction, with the aim of understanding how structural features are linked with functional-physiological aspects. Unfortunately, experimentally elucidated structural information is not yet available for the MC receptors, a group of class A G-protein coupled receptors (GPCRs). We, therefore, generated MC4R homology models and complexes with interacting partners to describe approximate structural properties associated with signaling mechanisms. In addition, molecular insights from pathogenic mutations were incorporated to discriminate more precisely their individual malfunction of the signal transfer mechanism.
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Affiliation(s)
- Nicolas Heyder
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Gunnar Kleinau
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- *Correspondence: Gunnar Kleinau
| | - Michal Szczepek
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Dennis Kwiatkowski
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - David Speck
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Lucia Soletto
- Departamento de Fisiología de Peces y Biotecnología, Consejo Superior de Investigaciones Científicas, Instituto de Acuicultura Torre de la Sal, Ribera de Cabanes, Spain
| | - José Miguel Cerdá-Reverter
- Departamento de Fisiología de Peces y Biotecnología, Consejo Superior de Investigaciones Científicas, Instituto de Acuicultura Torre de la Sal, Ribera de Cabanes, Spain
| | - Heiko Krude
- Institute of Experimental Pediatric Endocrinology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Peter Kühnen
- Institute of Experimental Pediatric Endocrinology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Patrick Scheerer
- Group Protein X-ray Crystallography and Signal Transduction, Institute of Medical Physics and Biophysics, Berlin Institute of Health, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Patrick Scheerer
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Martínez Damonte V, Rodríguez SS, Raingo J. Growth hormone secretagogue receptor constitutive activity impairs voltage-gated calcium channel-dependent inhibitory neurotransmission in hippocampal neurons. J Physiol 2018; 596:5415-5428. [PMID: 30199095 DOI: 10.1113/jp276256] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 09/06/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Presynaptic CaV 2 voltage-gated calcium channels link action potentials arriving at the presynaptic terminal to neurotransmitter release. Hence, their regulation is essential to fine tune brain circuitry. CaV 2 channels are highly sensitive to G protein-coupled receptor (GPCR) modulation. Our previous data indicated that growth hormone secretagogue receptor (GHSR) constitutive activity impairs CaV 2 channels by decreasing their surface density. We present compelling support for the impact of CaV 2.2 channel inhibition by agonist-independent GHSR activity exclusively on GABA release in hippocampal cultures. We found that this selectivity arises from a high reliance of GABA release on CaV 2.2 rather than on CaV 2.1 channels. Our data provide new information on the effects of the ghrelin-GHSR system on synaptic transmission, suggesting a putative physiological role of the constitutive signalling of a GPCR that is expressed at high levels in brain areas with restricted access to its natural agonist. ABSTRACT Growth hormone secretagogue receptor (GHSR) displays high constitutive activity, independent of its endogenous ligand, ghrelin. Unlike ghrelin-induced GHSR activity, the physiological role of GHSR constitutive activity and the mechanisms that underlie GHSR neuronal modulation remain elusive. We previously demonstrated that GHSR constitutive activity modulates presynaptic CaV 2 voltage-gated calcium channels. Here we postulate that GHSR constitutive activity-mediated modulation of CaV 2 channels could be relevant in the hippocampus since this brain area has high GHSR expression but restricted access to ghrelin. We performed whole-cell patch-clamp in hippocampal primary cultures from E16- to E18-day-old C57BL6 wild-type and GHSR-deficient mice after manipulating GHSR expression with lentiviral transduction. We found that GHSR constitutive activity impairs CaV 2.1 and CaV 2.2 native calcium currents and that CaV 2.2 basal impairment leads to a decrease in GABA but not glutamate release. We postulated that this selective effect is related to a higher CaV 2.2 over CaV 2.1 contribution to GABA release (∼40% for CaV 2.2 in wild-type vs. ∼20% in wild-type GHSR-overexpressing cultures). This effect of GHSR constitutive activity is conserved in hippocampal brain slices, where GHSR constitutive activity reduces local GABAergic transmission of the granule cell layer (intra-granule cell inhibitory postsynaptic current (IPSC) size ∼-67 pA in wild-type vs. ∼-100 pA in GHSR-deficient mice), whereas the glutamatergic output from the dentate gyrus to CA3 remains unchanged. In summary, we found that GHSR constitutive activity impairs IPSCs both in hippocampal primary cultures and in brain slices through a CaV 2-dependent mechanism without affecting glutamatergic transmission.
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Affiliation(s)
- Valentina Martínez Damonte
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
| | - Silvia Susana Rodríguez
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
| | - Jesica Raingo
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
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Melanocortins, Melanocortin Receptors and Multiple Sclerosis. Brain Sci 2017; 7:brainsci7080104. [PMID: 28805746 PMCID: PMC5575624 DOI: 10.3390/brainsci7080104] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/07/2017] [Accepted: 08/08/2017] [Indexed: 02/07/2023] Open
Abstract
The melanocortins and their receptors have been extensively investigated for their roles in the hypothalamo-pituitary-adrenal axis, but to a lesser extent in immune cells and in the nervous system outside the hypothalamic axis. This review discusses corticosteroid dependent and independent effects of melanocortins on the peripheral immune system, central nervous system (CNS) effects mediated through neuronal regulation of immune system function, and direct effects on endogenous cells in the CNS. We have focused on the expression and function of melanocortin receptors in oligodendroglia (OL), the myelin producing cells of the CNS, with the goal of identifying new therapeutic approaches to decrease CNS damage in multiple sclerosis as well as to promote repair. It is clear that melanocortin signaling through their receptors in the CNS has potential for neuroprotection and repair in diseases like MS. Effects of melanocortins on the immune system by direct effects on the circulating cells (lymphocytes and monocytes) and by signaling through CNS cells in regions lacking a mature blood brain barrier are clear. However, additional studies are needed to develop highly effective MCR targeted therapies that directly affect endogenous cells of the CNS, particularly OL, their progenitors and neurons.
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Abstract
Many of the neurocircuits and hormones known to underlie the sensations of hunger and satiety also substantially alter the activity of the dopaminergic reward system. Much interest lies in the ways that hunger, satiety, and reward tie together, as the epidemic of obesity seems tied to the recent development and mass availability of highly palatable foods. In this review, we will first discuss the basic neurocircuitry of the midbrain and basal forebrain reward system. We will elaborate how several important mediators of hunger-the agouti-related protein neurons of the arcuate nucleus, the lateral hypothalamic nucleus, and ghrelin-enhance the sensitivity of the dopaminergic reward system. Then, we will elaborate how mediators of satiety-the nucleus tractus solitarius, pro-opiomelanocortin neurons of the arcuate nucleus, and its peripheral hormonal influences such as leptin-reduce the reward system sensitivity. We hope to provide a template by which future research may identify the ways in which highly rewarding foods bypass this balanced system to produce excessive food consumption.
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Affiliation(s)
- Ryan Michael Cassidy
- Brown Foundation of the Institute of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, Neuroscience Program MD Anderson Cancer Center and UTHealth Graduate School of Biological Sciences, The University of Texas Health Science Center at Houston, Houston, TX, USA
- *Correspondence: Ryan Michael Cassidy,
| | - Qingchun Tong
- Brown Foundation of the Institute of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, Neuroscience Program MD Anderson Cancer Center and UTHealth Graduate School of Biological Sciences, The University of Texas Health Science Center at Houston, Houston, TX, USA
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