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Vlachodimou A, IJzerman AP, Heitman LH. Label-free detection of transporter activity via GPCR signalling in living cells: A case for SLC29A1, the equilibrative nucleoside transporter 1. Sci Rep 2019; 9:13802. [PMID: 31551431 PMCID: PMC6760145 DOI: 10.1038/s41598-019-48829-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 08/06/2019] [Indexed: 12/31/2022] Open
Abstract
Transporters are important therapeutic but yet understudied targets due to lack of available assays. Here we describe a novel label-free, whole-cell method for the functional assessment of Solute Carrier (SLC) inhibitors. As many SLC substrates are also ligands for G protein-coupled receptors (GPCRs), transporter inhibition may affect GPCR signalling due to a change in extracellular concentration of the substrate/ligand, which can be monitored by an impedance-based label-free assay. For this study, a prototypical SLC/GPCR pair was selected, i.e. the equilibrative nucleoside transporter-1 (SLC29A1/ENT1) and an adenosine receptor (AR), for which adenosine is the substrate/ligand. ENT1 inhibition with three reference compounds was monitored sensitively via AR activation on human osteosarcoma cells. Firstly, the inhibitor addition resulted in an increased apparent potency of adenosine. Secondly, all inhibitors concentration-dependently increased the extracellular adenosine concentration, resulting in an indirect quantitative assessment of their potencies. Additionally, AR activation was abolished by AR antagonists, confirming that the monitored impedance was AR-mediated. In summary, we developed a novel assay as an in vitro model system that reliably assessed the potency of SLC29A1 inhibitors via AR signalling. As such, the method may be applied broadly as it has the potential to study a multitude of SLCs via concomitant GPCR signalling.
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Affiliation(s)
- Anna Vlachodimou
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
| | - Adriaan P IJzerman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
| | - Laura H Heitman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research (LACDR), Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands.
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Vendramin Pasquetti M, Meier L, Loureiro S, Ganzella M, Junges B, Barbieri Caus L, Umpierrez Amaral A, Koeller DM, Goodman S, Woontner M, Gomes de Souza DO, Wajner M, Calcagnotto ME. Impairment of GABAergic system contributes to epileptogenesis in glutaric acidemia type I. Epilepsia 2017; 58:1771-1781. [PMID: 28762469 DOI: 10.1111/epi.13862] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Glutaric acidemia type I (GA-I) is an inherited neurometabolic disorder caused by deficiency of glutaryl-CoA dehydrogenase (GCDH) and characterized by increased levels of glutaric, 3-OH-glutaric, and glutaconic acids in the brain parenchyma. The increment of these organic acids inhibits glutamate decarboxylase (GAD) and consequently lowers the γ-aminobutyric acid (GABA) synthesis. Untreated patients exhibit severe neurologic deficits during development, including epilepsy, especially following an acute encephalopathy outbreak. In this work, we evaluated the role of the GABAergic system on epileptogenesis in GA-I using the Gcdh-/- mice exposed to a high lysine diet (Gcdh-/- -Lys). METHODS Spontaneous recurrent seizures (SRS), seizure susceptibility, and changes in brain oscillations were evaluated by video-electroencephalography (EEG). Cortical GABAergic synaptic transmission was evaluated using electrophysiologic and neurochemical approaches. RESULTS SRS were observed in 72% of Gcdh-/- -Lys mice, whereas no seizures were detected in age-matched controls (Gcdh+/+ or Gcdh-/- receiving normal diet). The severity and number of PTZ-induced seizures were higher in Gcdh-/- -Lys mice. EEG spectral analysis showed a significant decrease in theta and gamma oscillations and predominant delta waves in Gcdh-/- -Lys mice, associated with increased EEG left index. Analysis of cortical synaptosomes revealed a significantly increased percentage of glutamate release and decreased GABA release in Gcdh-/- -Lys mice that were associated with a decrease in cortical GAD immunocontent and activity and confirmed by reduced frequency of inhibitory events in cortical pyramidal cells. SIGNIFICANCE Using an experimental model with a phenotype similar to that of GA-I in humans-the Gcdh-/- mice under high lysine diet (Gcdh-/- -Lys)-we provide evidence that a reduction in cortical inhibition of Gcdh-/- -Lys mice, probably induced by GAD dysfunction, leads to hyperexcitability and increased slow oscillations associated with neurologic abnormalities in GA-I. Our findings offer a new perspective on the pathophysiology of brain damage in GA-I.
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Affiliation(s)
- Mayara Vendramin Pasquetti
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory-NNNESP Lab.), Biochemistry Department, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Letícia Meier
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory-NNNESP Lab.), Biochemistry Department, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Samanta Loureiro
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Marcelo Ganzella
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Bernardo Junges
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory-NNNESP Lab.), Biochemistry Department, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Letícia Barbieri Caus
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory-NNNESP Lab.), Biochemistry Department, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Alexandre Umpierrez Amaral
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - David M Koeller
- Department of Pediatrics, Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, U.S.A
| | - Stephen Goodman
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, U.S.A
| | - Michael Woontner
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, U.S.A
| | - Diogo Onofre Gomes de Souza
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Moacir Wajner
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Maria Elisa Calcagnotto
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory-NNNESP Lab.), Biochemistry Department, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Postgraduate Program in Neuroscience, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Wu YB, Zhang L, Li WT, Yang Y, Zhao JM. Artesunate restores spatial learning of rats with hepatic encephalopathy by inhibiting ammonia-induced oxidative damage in neurons and dysfunction of glutamate signaling in astroglial cells. Biomed Pharmacother 2016; 84:972-978. [PMID: 27764760 DOI: 10.1016/j.biopha.2016.09.104] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/20/2016] [Accepted: 09/27/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Artesunate (ART) is an antimalarial drug with potential anti-inflammatory effect. This study aimed to explore the potential protective role of ART in hepatic encephalopathy (HE), involving its function against ammonia toxicity. METHODS HE rats were induced by the administration of thioacetamide (TAA, 300mg/kg/day). Spatial learning ability was tested in both Morris water and eight-arm radial maze. Rat cerebellar granule neurons (CGNs) were prepared for ammonia treatment in vitro, in line with SH-SY5Y and C6 cells. ART was administrated at 50 or 100mg/kg/day in vivo or added at 50 or 100μM in vitro. Oxidative damages were evaluated by the changes of cell viability, reactive oxygen species (ROS) levels and glutathione (GSH) content, while glutamate uptake and release, and the activities of glutamine synthetase (GS) and Na+K+-ATPase were measured to indicate the dysfunction of glutamate signaling. RESULTS Decreased escape latency and increased numbers of working errors were observed in TAA-induced HE rats, which could be significantly restored by ART at a dosage-dependent manner. Decreased cell viability and GSH content and increased ROS accumulation were detected in ammonia-treated SH-SY5Y and CGNs, while ammonia-treated C6 cells showed reduced glutamate uptake, increased glutamate release, and decrease of GSH content, GS and Na+K+-ATPase activity. In contrast, ART, especially at 100μM, strongly reversed all changes induced by ammonia, showing a similar dosage-dependent manner in vitro. CONCLUSION This study revealed a new neuroprotective role of ART in the pathogenesis of HE, by protecting neurons and astroglial cells from ammonia-induced damages and dysfunctions.
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Affiliation(s)
- Yuan-Bo Wu
- Department of Neurology, Provincial Hospital Affiliated to Anhui Medical University, HeFei 230001, Anhui Province, China
| | - Li Zhang
- Department of Neurology, Provincial Hospital Affiliated to Anhui Medical University, HeFei 230001, Anhui Province, China
| | - Wen-Ting Li
- Department of Infectious Disease, Provincial Hospital Affiliated to Anhui Medical University, HeFei 230001, Anhui Province, China
| | - Yi Yang
- Department of Neurology, Provincial Hospital Affiliated to Anhui Medical University, HeFei 230001, Anhui Province, China
| | - Jiang-Ming Zhao
- Department of Neurology, Provincial Hospital Affiliated to Anhui Medical University, HeFei 230001, Anhui Province, China.
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Bobermin LD, Wartchow KM, Flores MP, Leite MC, Quincozes-Santos A, Gonçalves CA. Ammonia-induced oxidative damage in neurons is prevented by resveratrol and lipoic acid with participation of heme oxygenase 1. Neurotoxicology 2015; 49:28-35. [PMID: 26003724 DOI: 10.1016/j.neuro.2015.05.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 05/14/2015] [Accepted: 05/15/2015] [Indexed: 12/29/2022]
Abstract
Ammonia is a metabolite that, at high concentrations, is implicated in neurological disorders, such as hepatic encephalopathy (HE), which is associated with acute or chronic liver failure. Astrocytes are considered the primary target of ammonia toxicity in the central nervous system (CNS) because glutamine synthetase (GS), responsible for ammonia metabolism in CNS, is an astrocytic enzyme. Thus, neuronal dysfunction has been associated as secondary to astrocytic impairment. However, we demonstrated that ammonia can induce direct effects on neuronal cells. The cell viability was decreased by ammonia in SH-SY5Y cells and cerebellar granule neurons. In addition, ammonia induced increased reactive oxygen species (ROS) production and decreased GSH intracellular content, the main antioxidant in CNS. As ammonia neurotoxicity is strongly associated with oxidative stress, we also investigated the potential neuroprotective roles of the antioxidants, resveratrol (RSV) and lipoic acid (LA), against ammonia toxicity in cerebellar granule neurons. RSV and LA were able to prevent the oxidative damage induced by ammonia, maintaining the levels of ROS production and GSH close to basal values. Both antioxidants also decreased ROS production and increased GSH content under basal conditions (in the absence of ammonia). Moreover, we showed that heme oxygenase 1 (HO1), a protein associated with protection against stress conditions, is involved in the beneficial effects of RSV and LA in cerebellar granule neurons. Thus, this study reinforces the neuroprotective effects of RSV and LA. Although more studies in vivo are required, RSV and LA could represent interesting therapeutic strategies for the management of HE.
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Affiliation(s)
- Larissa Daniele Bobermin
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
| | - Krista Minéia Wartchow
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Marianne Pires Flores
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Marina Concli Leite
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - André Quincozes-Santos
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Carlos-Alberto Gonçalves
- Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
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