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Zhu Y, Sun H, Wang H, Li N. Synaptic mechanisms underlying the elevated sympathetic outflow in fructose-induced hypertension. Front Physiol 2024; 15:1365594. [PMID: 38505704 PMCID: PMC10949223 DOI: 10.3389/fphys.2024.1365594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 02/05/2024] [Indexed: 03/21/2024] Open
Abstract
Metabolic syndrome is associated with cardiovascular dysfunction, including elevated sympathetic outflow. However, the underlying brain mechanisms are unclear. The nucleus tractus solitarius (NTS) critically regulates autonomic reflexes related to cardiovascular function and contains neurons projecting to the caudal ventrolateral medulla (CVLM). Nitric oxide (NO) is a diffusible free-radical messenger in the vascular, immune, and nervous systems. In this study, we determine if NO in the NTS is involved in the synaptic plasticity underlying the elevated sympathetic outflow in fructose-induced hypertension. We retrogradely labeled CVLM-projecting NTS neurons through the injection of FluoSpheres into the CVLM in a fructose-fed rat model to determine the cellular mechanism involved in increased sympathetic outflow. Fructose feeding increased the blood pressure and glucose levels, which represent metabolic syndrome. We found that fructose feeding reduces the NO precursor L-arginine-induced increase in the firing activity of CVLM-projecting NTS neurons. Furthermore, fructose feeding reduces the L-arginine-induced increase in presynaptic spontaneous glutamatergic synaptic inputs to NTS neurons, while NO donor DEA/NO produces an increase in glutamatergic synaptic inputs in fructose-fed rats similar to that in vehicle-treated rats. In addition, fructose feeding reduces the NO-induced depressor response and sympathoinhibition. These data suggested that fructose feeding reduced NO production and, thus, the subsequent NO-induced glutamate releases in the NTS and depressor response. The findings of this study provide new insights into the central mechanisms involved in the neural control of cardiovascular and autonomic functions in the NTS in metabolic syndrome.
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Affiliation(s)
- Yun Zhu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Haiying Sun
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hongjie Wang
- Department of Anesthesiology, Affiliated Hospital of Hebei University, Baoding, China
| | - Na Li
- Department of Physiology, School of Basic Medical Sciences, Hebei University, Baoding, China
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Nelissen E, Schepers M, Ponsaerts L, Foulquier S, Bronckaers A, Vanmierlo T, Sandner P, Prickaerts J. Soluble guanylyl cyclase: A novel target for the treatment of vascular cognitive impairment? Pharmacol Res 2023; 197:106970. [PMID: 37884069 DOI: 10.1016/j.phrs.2023.106970] [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: 06/19/2023] [Revised: 10/16/2023] [Accepted: 10/23/2023] [Indexed: 10/28/2023]
Abstract
Vascular cognitive impairment (VCI) describes neurodegenerative disorders characterized by a vascular component. Pathologically, it involves decreased cerebral blood flow (CBF), white matter lesions, endothelial dysfunction, and blood-brain barrier (BBB) impairments. Molecularly, oxidative stress and inflammation are two of the major underlying mechanisms. Nitric oxide (NO) physiologically stimulates soluble guanylate cyclase (sGC) to induce cGMP production. However, under pathological conditions, NO seems to be at the basis of oxidative stress and inflammation, leading to a decrease in sGC activity and expression. The native form of sGC needs a ferrous heme group bound in order to be sensitive to NO (Fe(II)sGC). Oxidation of sGC leads to the conversion of ferrous to ferric heme (Fe(III)sGC) and even heme-loss (apo-sGC). Both Fe(III)sGC and apo-sGC are insensitive to NO, and the enzyme is therefore inactive. sGC activity can be enhanced either by targeting the NO-sensitive native sGC (Fe(II)sGC), or the inactive, oxidized sGC (Fe(III)sGC) and the heme-free apo-sGC. For this purpose, sGC stimulators acting on Fe(II)sGC and sGC activators acting on Fe(III)sGC/apo-sGC have been developed. These sGC agonists have shown their efficacy in cardiovascular diseases by restoring the physiological and protective functions of the NO-sGC-cGMP pathway, including the reduction of oxidative stress and inflammation, and improvement of vascular functioning. Yet, only very little research has been performed within the cerebrovascular system and VCI pathology when focusing on sGC modulation and its potential protective mechanisms on vascular and neural function. Therefore, within this review, the potential of sGC as a target for treating VCI is highlighted.
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Affiliation(s)
- Ellis Nelissen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands.
| | - Melissa Schepers
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands; Neuro-immune connect and repair lab, Biomedical Research Institute, Hasselt University, Hasselt 3500, Belgium
| | - Laura Ponsaerts
- Neuro-immune connect and repair lab, Biomedical Research Institute, Hasselt University, Hasselt 3500, Belgium; Department of Cardio & Organ Systems (COS), Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Sébastien Foulquier
- Department of Pharmacology and Toxicology, School for Mental Health and Neuroscience (MHeNS), School for Cardiovascular Diseases (CARIM), Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Annelies Bronckaers
- Department of Cardio & Organ Systems (COS), Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Tim Vanmierlo
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands; Neuro-immune connect and repair lab, Biomedical Research Institute, Hasselt University, Hasselt 3500, Belgium
| | - Peter Sandner
- Bayer AG, Pharmaceuticals R&D, Pharma Research Center, 42113 Wuppertal, Germany; Hannover Medical School, 30625 Hannover, Germany
| | - Jos Prickaerts
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
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Giesen J, Mergia E, Koesling D, Russwurm M. Hippocampal AMPA- and NMDA-induced cGMP signals are mainly generated by NO-GC2 and are under tight control by PDEs 1 and 2. Eur J Neurosci 2021; 55:18-31. [PMID: 34902209 DOI: 10.1111/ejn.15564] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 11/29/2021] [Accepted: 12/07/2021] [Indexed: 11/30/2022]
Abstract
In the central nervous system, the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signalling cascade has an established role in fine-tuning of synaptic transmission. In the present study, we asked which isoform of NO-sensitive guanylyl cyclase, NO-GC1 or NO-GC2, is responsible for generation of N-methyl-d-aspartate (NMDA)- and AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)-induced cGMP signals and which of the phosphodiesterases (PDEs) is responsible for degradation. To this end, we performed live cell fluorescence measurements of primary hippocampal neurons isolated from NO-GC isoform-deficient mice. Although both isoforms contributed to the NMDA- and AMPA-induced cGMP signals, NO-GC2 clearly played the predominant role. Whereas under PDE-inhibiting conditions the cGMP levels elicited by both glutamatergic ligands were comparable, NMDA-induced cGMP signals were clearly higher than the AMPA-induced ones in the absence of PDE inhibitors. Thus, AMPA-induced cGMP signals are more tightly controlled by PDE-mediated degradation than NMDA-induced signals. In addition, these findings are compatible with the existence of at least two different pools of cGMP in both of which PDE1 and PDE2-known to be highly expressed in the hippocampus-are mainly responsible for cGMP degradation. The finding that distinct pools of cGMP are equipped with different amounts of PDEs highlights the importance of PDEs for the shape of NO-induced cGMP signals in the central nervous system.
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Affiliation(s)
- Jan Giesen
- Institute of Pharmacology and Toxicology, Ruhr-University Bochum, Bochum, Germany
| | - Evanthia Mergia
- Institute of Pharmacology and Toxicology, Ruhr-University Bochum, Bochum, Germany
| | - Doris Koesling
- Institute of Pharmacology and Toxicology, Ruhr-University Bochum, Bochum, Germany
| | - Michael Russwurm
- Institute of Pharmacology and Toxicology, Ruhr-University Bochum, Bochum, Germany
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Feil R, Lehners M, Stehle D, Feil S. Visualising and understanding cGMP signals in the cardiovascular system. Br J Pharmacol 2021; 179:2394-2412. [PMID: 33880767 DOI: 10.1111/bph.15500] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 03/14/2021] [Accepted: 04/01/2021] [Indexed: 12/21/2022] Open
Abstract
cGMP is an important signalling molecule in humans. Fluorescent cGMP biosensors have emerged as powerful tools for the sensitive analysis of cGMP pathways at the single-cell level. Here, we briefly outline cGMP's multifaceted role in (patho)physiology and pharmacotherapy. Then we summarise what new insights cGMP imaging has provided into endogenous cGMP signalling and drug action, with a focus on the cardiovascular system. Indeed, the use of cGMP biosensors has led to several conceptual advances, such as the discovery of local, intercellular and mechanosensitive cGMP signals. Importantly, single-cell imaging can provide valuable information about the heterogeneity of cGMP signals within and between individual cells of an isolated cell population or tissue. We also discuss current challenges and future directions of cGMP imaging, such as the direct visualisation of cGMP microdomains, simultaneous monitoring of cGMP and other signalling molecules and, ultimately, cGMP imaging in tissues and animals under close-to-native conditions.
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Affiliation(s)
- Robert Feil
- Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany
| | - Moritz Lehners
- Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany
| | - Daniel Stehle
- Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany
| | - Susanne Feil
- Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany
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Zhang D, Dong X, Liu X, Ye L, Li S, Zhu R, Ye Y, Jiang Y. Proteomic Analysis of Brain Regions Reveals Brain Regional Differences and the Involvement of Multiple Keratins in Chronic Alcohol Neurotoxicity. Alcohol Alcohol 2020; 55:147-156. [PMID: 32047899 DOI: 10.1093/alcalc/agaa007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/22/2019] [Accepted: 01/13/2020] [Indexed: 12/29/2022] Open
Abstract
AIMS Alcohol abuse has attracted public attention and chronic alcohol exposure can result in irreversible structural changes in the brain. The molecular mechanisms underlying alcohol neurotoxicity are complex, mandating comprehensive mining of spatial protein expression profile. METHODS In this study, mice models of chronic alcohol intoxication were established after 95% alcohol vapor administration for 30 consecutive days. On Day 30, striatum (the dorsal and ventral striatum) and hippocampus, the two major brain regions responsible for learning and memorizing while being sensitive to alcohol toxicity, were collected. After that, isobaric tags for relative and absolute quantitation -based quantitative proteomic analysis were carried out for further exploration of the novel mechanisms underlying alcohol neurotoxicity. RESULTS Proteomic results showed that in the striatum, 29 proteins were significantly up-regulated and 17 proteins were significantly down-regulated. In the hippocampus, 72 proteins were significantly up-regulated, while 2 proteins were significantly down-regulated. Analysis of the overlay proteins revealed that a total of 102 proteins were consistently altered (P < 0.05) in both hippocampus and striatum regions, including multiple keratins such as Krt6a, Krt17 and Krt5. Ingenuity pathway analysis revealed that previously reported diseases/biofunctions such as dermatological diseases and developmental disorders were enriched in those proteins. Interestingly, the glucocorticoid receptor (GR) signaling was among the top enriched pathways in both brain regions, while multiple keratins from the GR signaling such as Krt1 and Krt17 exhibited significantly opposite expression patterns in the two brain nuclei. Moreover, there are several other involved pathways significantly differed between the hippocampus and striatum. CONCLUSIONS Our data revealed brain regional differences upon alcohol consumption and indicated the critical involvement of keratins from GR signaling in alcohol neurotoxicity. The differences in proteomic results between the striatum and hippocampus suggested a necessity of taking into consideration brain regional differences and intertwined signaling pathways rather than merely focusing on single nuclei or molecule during the study of drug-induced neurotoxicity in the future.
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Affiliation(s)
- Dingang Zhang
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Xiaoru Dong
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Xiaochen Liu
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Lin Ye
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Shuhao Li
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Rongzhe Zhu
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Yonghong Ye
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Yan Jiang
- Department of Forensic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
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Kelly MP, Heckman PRA, Havekes R. Genetic manipulation of cyclic nucleotide signaling during hippocampal neuroplasticity and memory formation. Prog Neurobiol 2020; 190:101799. [PMID: 32360536 DOI: 10.1016/j.pneurobio.2020.101799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/14/2020] [Accepted: 03/26/2020] [Indexed: 12/12/2022]
Abstract
Decades of research have underscored the importance of cyclic nucleotide signaling in memory formation and synaptic plasticity. In recent years, several new genetic techniques have expanded the neuroscience toolbox, allowing researchers to measure and modulate cyclic nucleotide gradients with high spatiotemporal resolution. Here, we will provide an overview of studies using genetic approaches to interrogate the role cyclic nucleotide signaling plays in hippocampus-dependent memory processes and synaptic plasticity. Particular attention is given to genetic techniques that measure real-time changes in cyclic nucleotide levels as well as newly-developed genetic strategies to transiently manipulate cyclic nucleotide signaling in a subcellular compartment-specific manner with high temporal resolution.
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Affiliation(s)
- Michy P Kelly
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, 6439 Garners Ferry Rd, VA Bldg1, 3(rd) Fl, D-12, Columbia, 29209, SC, USA.
| | - Pim R A Heckman
- Neurobiology Expertise Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands.
| | - Robbert Havekes
- Neurobiology Expertise Group, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Nijenborgh 7, 9747 AG Groningen, the Netherlands.
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Giesen J, Füchtbauer EM, Füchtbauer A, Funke K, Koesling D, Russwurm M. AMPA Induces NO-Dependent cGMP Signals in Hippocampal and Cortical Neurons via L-Type Voltage-Gated Calcium Channels. Cereb Cortex 2019; 30:2128-2143. [DOI: 10.1093/cercor/bhz227] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/28/2019] [Accepted: 08/28/2019] [Indexed: 02/06/2023] Open
Abstract
AbstractThe nitric oxide (NO)/cGMP signaling cascade has an established role in synaptic plasticity. However, with conventional methods, the underlying cGMP signals were barely detectable. Here, we set out to confirm the well-known NMDA-induced cGMP increases, to test the impact of AMPA on those signals, and to identify the relevant phosphodiesterases (PDEs) using a more sensitive fluorescence resonance energy transfer (FRET)-based method. Therefore, a “knock-in” mouse was generated that expresses a FRET-based cGMP indicator (cGi-500) allowing detection of cGMP concentrations between 100 nM and 3 μM. Measurements were performed in cultured hippocampal and cortical neurons as well as acute hippocampal slices. In hippocampal and cortical neurons, NMDA elicited cGMP signals half as high as the ones elicited by exogenous NO. Interestingly, AMPA increased cGMP independently of NMDA receptors and dependent on NO synthase (NOS) activation. NMDA- and AMPA-induced cGMP signals were not additive indicating that both pathways converge on the level of NOS. Accordingly, the same PDEs, PDE1 and PDE2, were responsible for degradation of NMDA- as well as AMPA-induced cGMP signals. Mechanistically, AMPAR induced calcium influx through L-type voltage-gated calcium channels leading to NOS and finally NO-sensitive guanylyl cyclase activation. Our results demonstrate that in addition to NMDA also AMPA triggers endogenous NO formation and hence cGMP production.
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Affiliation(s)
- Jan Giesen
- Institute of Pharmacology and Toxicology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Ernst-Martin Füchtbauer
- Molecular Cell and Developmental Biology, Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Annette Füchtbauer
- Molecular Cell and Developmental Biology, Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Klaus Funke
- Department of Neurophysiology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Doris Koesling
- Institute of Pharmacology and Toxicology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Michael Russwurm
- Institute of Pharmacology and Toxicology, Ruhr-University Bochum, 44780 Bochum, Germany
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Real-Time Imaging Reveals Augmentation of Glutamate-Induced Ca 2+ Transients by the NO-cGMP Pathway in Cerebellar Granule Neurons. Int J Mol Sci 2018; 19:ijms19082185. [PMID: 30049956 PMCID: PMC6121606 DOI: 10.3390/ijms19082185] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 07/13/2018] [Accepted: 07/23/2018] [Indexed: 01/11/2023] Open
Abstract
Dysfunctions of NO-cGMP signaling have been implicated in various neurological disorders. We have studied the potential crosstalk of cGMP and Ca2+ signaling in cerebellar granule neurons (CGNs) by simultaneous real-time imaging of these second messengers in living cells. The NO donor DEA/NO evoked cGMP signals in the granule cell layer of acute cerebellar slices from transgenic mice expressing a cGMP sensor protein. cGMP and Ca2+ dynamics were visualized in individual CGNs in primary cultures prepared from 7-day-old cGMP sensor mice. DEA/NO increased the intracellular cGMP concentration and augmented glutamate-induced Ca2+ transients. These effects of DEA/NO were absent in CGNs isolated from knockout mice lacking NO-sensitive guanylyl cyclase. Furthermore, application of the cGMP analogues 8-Br-cGMP and 8-pCPT-cGMP, which activate cGMP effector proteins such as cyclic nucleotide-gated cation channels and cGMP-dependent protein kinases (cGKs), also potentiated glutamate-induced Ca2+ transients. Western blot analysis failed to detect cGK type I or II in our primary CGNs. The addition of phosphodiesterase (PDE) inhibitors during cGMP imaging showed that CGNs degrade cGMP mainly via Zaprinast-sensitive PDEs, most likely PDE5 and/or PDE10, but not via PDE1, 2, or 3. In sum, these data delineate a cGK-independent NO-cGMP signaling cascade that increases glutamate-induced Ca2+ signaling in CGNs. This cGMP–Ca2+ crosstalk likely affects neurotransmitter-stimulated functions of CGNs.
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