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Di Cerbo A, Roncati L, Marini C, Carnevale G, Zavatti M, Avallone R, Corsi L. Possible Association Between DHEA and PKCε in Hepatic Encephalopathy Amelioration: A Pilot Study. Front Vet Sci 2021; 8:695375. [PMID: 34651032 PMCID: PMC8505975 DOI: 10.3389/fvets.2021.695375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/25/2021] [Indexed: 12/18/2022] Open
Abstract
Objective: Hepatic encephalopathy (HE) is a neuropsychiatric syndrome caused by liver failure and by an impaired neurotransmission and neurological function caused by hyperammonemia (HA). HE, in turn, decreases the phosphorylation of protein kinase C epsilon (PKCε), contributing to the impairment of neuronal functions. Dehydroepiandrosterone (DHEA) exerts a neuroprotective effect by increasing the GABAergic tone through GABAA receptor stimulation. Therefore, we investigated the protective effect of DHEA in an animal model of HE, and the possible modulation of PKCε expression in different brain area. Methods: Fulminant hepatic failure was induced in 18 male, Sprague–Dawley rats by i.p. administration of 3 g/kg D-galactosamine, and after 30 min, a group of animals received a subcutaneous injection of 25 mg/kg (DHEA) repeated twice a day (3 days). Exploratory behavior and general activity were evaluated 24 h and 48 h after the treatments by the open field test. Then, brain cortex and cerebellum were used for immunoblotting analysis of PKCε level. Results: DHEA administration showed a significant improvement of locomotor activity both 24 and 48 h after D-galactosamine treatment (****p < 0.0001) but did not ameliorate liver parenchymal degeneration. Western blot analysis revealed a reduced immunoreactivity of PKCε (*p < 0.05) following D-galactosamine treatment in rat cortex and cerebellum. After the addition of DHEA, PKCε increased in the cortex in comparison with the D-galactosamine-treated (***p < 0.001) and control group (*p < 0.05), but decreased in the cerebellum (*p < 0.05) with respect to the control group. PKCε decreased after treatment with NH4Cl alone and in combination with DHEA in both cerebellum and cortex (****p < 0.0001). MTS assay demonstrated the synergistic neurotoxic action of NH4Cl and glutamate pretreatment in cerebellum and cortex along with an increased cell survival after DHEA pretreatment, which was significant only in the cerebellum (*p < 0.05). Conclusion: An association between the DHEA-mediated increase of PKCε expression and the improvement of comatose symptoms was observed. PKCε activation and expression in the brain could inhibit GABA-ergic tone counteracting HE symptoms. In addition, DHEA seemed to ameliorate the symptoms of HE and to increase the expression of PKCε in cortex and cerebellum.
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Affiliation(s)
- Alessandro Di Cerbo
- School of Biosciences and Veterinary Medicine, University of Camerino, Matelica, Italy
| | - Luca Roncati
- Institute of Pathology, University of Modena and Reggio Emilia, Modena, Italy
| | - Carlotta Marini
- School of Biosciences and Veterinary Medicine, University of Camerino, Matelica, Italy
| | - Gianluca Carnevale
- Surgical, Medical and Dental Department of Morphological Sciences Related to Transplant, Oncology and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy
| | - Manuela Zavatti
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Rossella Avallone
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Lorenzo Corsi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy.,National Institute of Biostructure and Biosystems, Rome, Italy
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Limón ID, Angulo-Cruz I, Sánchez-Abdon L, Patricio-Martínez A. Disturbance of the Glutamate-Glutamine Cycle, Secondary to Hepatic Damage, Compromises Memory Function. Front Neurosci 2021; 15:578922. [PMID: 33584185 PMCID: PMC7873464 DOI: 10.3389/fnins.2021.578922] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 01/06/2021] [Indexed: 12/13/2022] Open
Abstract
Glutamate fulfils many vital functions both at a peripheral level and in the central nervous system (CNS). However, hyperammonemia and hepatic failure induce alterations in glutamatergic neurotransmission, which may be the main cause of hepatic encephalopathy (HE), an imbalance which may explain damage to both learning and memory. Cognitive and motor alterations in hyperammonemia may be caused by a deregulation of the glutamate-glutamine cycle, particularly in astrocytes, due to the blocking of the glutamate excitatory amino-acid transporters 1 and 2 (EAAT1, EAAT2). Excess extracellular glutamate triggers mechanisms involving astrocyte-mediated inflammation, including the release of Ca2+-dependent glutamate from astrocytes, the appearance of excitotoxicity, the formation of reactive oxygen species (ROS), and cell damage. Glutamate re-uptake not only prevents excitotoxicity, but also acts as a vital component in synaptic plasticity and function. The present review outlines the evidence of the relationship between hepatic damage, such as that occurring in HE and hyperammonemia, and changes in glutamine synthetase function, which increase glutamate concentrations in the CNS. These conditions produce dysfunction in neuronal communication. The present review also includes data indicating that hyperammonemia is related to the release of a high level of pro-inflammatory factors, such as interleukin-6, by astrocytes. This neuroinflammatory condition alters the function of the membrane receptors, such as N-methyl-D-aspartate (NMDA), (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) AMPA, and γ-aminobutyric acid (GABA), thus affecting learning and spatial memory. Data indicates that learning and spatial memory, as well as discriminatory or other information acquisition processes in the CNS, are damaged by the appearance of hyperammonemia and, moreover, are associated with a reduction in the production of cyclic guanosine monophosphate (cGMP). Therefore, increased levels of pharmacologically controlled cGMP may be used as a therapeutic tool for improving learning and memory in patients with HE, hyperammonemia, cerebral oedema, or reduced intellectual capacity.
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Affiliation(s)
| | - Isael Angulo-Cruz
- Laboratorio de Neurofarmacología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Lesli Sánchez-Abdon
- Laboratorio de Neurofarmacología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Aleidy Patricio-Martínez
- Laboratorio de Neurofarmacología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
- Facultad de Ciencias Biológicas, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
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Dąbrowska K, Albrecht J, Zielińska M. Protein kinase C-mediated impairment of glutamine outward transport and SN1 transporter distribution by ammonia in mouse cortical astrocytes. Neurochem Int 2018; 118:225-232. [DOI: 10.1016/j.neuint.2018.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 06/19/2018] [Accepted: 07/03/2018] [Indexed: 01/07/2023]
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Song Y, Bei Y, Mao D, Ding W, Lin Z. A combination of gangliosides and nerve growth factor alleviates lipopolysaccharide-induced neuronal cells damage and its mechanism. BIO WEB OF CONFERENCES 2017. [DOI: 10.1051/bioconf/20170801025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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5
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Lucke-Wold BP, Logsdon AF, Smith KE, Turner RC, Alkon DL, Tan Z, Naser ZJ, Knotts CM, Huber JD, Rosen CL. Bryostatin-1 Restores Blood Brain Barrier Integrity following Blast-Induced Traumatic Brain Injury. Mol Neurobiol 2015; 52:1119-1134. [PMID: 25301233 PMCID: PMC5000781 DOI: 10.1007/s12035-014-8902-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/24/2014] [Indexed: 02/08/2023]
Abstract
Recent wars in Iraq and Afghanistan have accounted for an estimated 270,000 blast exposures among military personnel. Blast traumatic brain injury (TBI) is the 'signature injury' of modern warfare. Blood brain barrier (BBB) disruption following blast TBI can lead to long-term and diffuse neuroinflammation. In this study, we investigate for the first time the role of bryostatin-1, a specific protein kinase C (PKC) modulator, in ameliorating BBB breakdown. Thirty seven Sprague-Dawley rats were used for this study. We utilized a clinically relevant and validated blast model to expose animals to moderate blast exposure. Groups included: control, single blast exposure, and single blast exposure + bryostatin-1. Bryostatin-1 was administered i.p. 2.5 mg/kg after blast exposure. Evan's blue, immunohistochemistry, and western blot analysis were performed to assess injury. Evan's blue binds to albumin and is a marker for BBB disruption. The single blast exposure caused an increase in permeability compared to control (t = 4.808, p < 0.05), and a reduction back toward control levels when bryostatin-1 was administered (t = 5.113, p < 0.01). Three important PKC isozymes, PKCα, PKCδ, and PKCε, were co-localized primarily with endothelial cells but not astrocytes. Bryostatin-1 administration reduced toxic PKCα levels back toward control levels (t = 4.559, p < 0.01) and increased the neuroprotective isozyme PKCε (t = 6.102, p < 0.01). Bryostatin-1 caused a significant increase in the tight junction proteins VE-cadherin, ZO-1, and occludin through modulation of PKC activity. Bryostatin-1 ultimately decreased BBB breakdown potentially due to modulation of PKC isozymes. Future work will examine the role of bryostatin-1 in preventing chronic neurodegeneration following repetitive neurotrauma.
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Affiliation(s)
- Brandon P Lucke-Wold
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
| | - Aric F Logsdon
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, 26506, USA
| | - Kelly E Smith
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, 26506, USA
| | - Ryan C Turner
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
| | - Daniel L Alkon
- Blanchette Rockefeller Neurosciences Institute, Morgantown, WV, 26506, USA
| | - Zhenjun Tan
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
| | - Zachary J Naser
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- Office of Professional Studies in Health Sciences, Drexel University College of Medicine, Philadelphia, PA, 19102, USA
| | - Chelsea M Knotts
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
| | - Jason D Huber
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, 26506, USA
| | - Charles L Rosen
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, 26506, USA.
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, 26506, USA.
- Department of Neurosurgery, West Virginia University School of Medicine, One Medical Center Drive, Suite 4300, Health Sciences Center, PO Box 9183, Morgantown, WV, 26506-9183, USA.
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Wen S, Schroeter A, Klöcker N. Synaptic plasticity in hepatic encephalopathy - a molecular perspective. Arch Biochem Biophys 2013; 536:183-8. [PMID: 23624147 DOI: 10.1016/j.abb.2013.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 04/13/2013] [Accepted: 04/15/2013] [Indexed: 01/04/2023]
Abstract
Hepatic encephalopathy (HE)(1) is a common neuropsychiatric complication of both acute and chronic liver disease. Clinical symptoms may include motor disturbances and cognitive dysfunction. Available animal models of HE mimic the deficits in cognitive performance including the impaired ability to learn and memorize information. This review explores the question how HE might affect cognitive functions at molecular levels. Both acute and chronic models of HE constrain the plasticity of glutamatergic neurotransmission. Thus, long-lasting activity-dependent changes in synaptic efficiency, known as long-term potentiation (LTP) and long-term depression (LTD) are significantly impeded. We discuss molecules and signal transduction pathways of LTP and LTD that are targeted by experimental HE, with a focus on ionotropic glutamate receptors of the AMPA-subtype. Finally, a novel strategy of functional proteomic analysis is presented, which, if applied differentially, may provide molecular insight into disease-related dysfunction of membrane protein complexes, i.e. disturbed ionotropic glutamate receptor signaling in HE.
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Affiliation(s)
- Shuping Wen
- Institute of Neural and Sensory Physiology, Medical Faculty, University of Düsseldorf D-40225 Düsseldorf, Germany
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Lee J, Saloman JL, Weiland G, Auh QS, Chung MK, Ro JY. Functional interactions between NMDA receptors and TRPV1 in trigeminal sensory neurons mediate mechanical hyperalgesia in the rat masseter muscle. Pain 2012; 153:1514-1524. [PMID: 22609428 DOI: 10.1016/j.pain.2012.04.015] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/07/2012] [Accepted: 04/12/2012] [Indexed: 12/18/2022]
Abstract
The NMDA and TRPV1 receptors that are expressed in sensory neurons have been independently demonstrated to play important roles in peripheral pain mechanisms. In the present study, we investigated whether the 2 receptor-channel systems form a functional complex that provides the basis for the development of mechanical hyperalgesia. In the masseter muscle, direct application of NMDA induced a time-dependent increase in mechanical sensitivity, which was significantly blocked when the muscle was pretreated with a specific TRPV1 antagonist, AMG9810. The NR1 subunit of the NMDA receptor and TRPV1 were coexpressed in 32% of masseter afferents in trigeminal ganglia (TG). Furthermore, NR1 and NR2B formed protein-protein complexes with TRPV1 in TG as demonstrated by coimmunoprecipitation experiments. Calcium imaging analyses further corroborated that NMDA and TRPV1 receptors functionally interact. In TG culture, application of NMDA resulted in phosphorylation of serine, but not threonine or tyrosine, residues of TRPV1 in a time course similar to that of the development of NMDA-induced mechanical hyperalgesia. The NMDA-induced phosphorylation was significantly attenuated by CaMKII and PKC inhibitors, but not by a PKA inhibitor. Consistent with the biochemical data, the NMDA-induced mechanical hyperalgesia was also effectively blocked when the muscle was pretreated with a CaMKII or PKC inhibitor. Thus, NMDA receptors and TRPV1 functionally interact via CaMKII and PKC signaling cascades and contribute to mechanical hyperalgesia. These data offer novel mechanisms by which 2 ligand-gated channels in sensory neurons interact and reinforce the notion that TRPV1 functions as a signal integrator under pathological conditions.
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Affiliation(s)
- Jongseok Lee
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, Program in Neuroscience, Baltimore, MA, USA Kyung Hee University, School of Dentistry, Department of Oral Medicine, Seoul, Republic of Korea
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Cabrera-Pastor A, Llansola M, Reznikov V, Boix J, Felipo V. Differential effects of chronic hyperammonemia on modulation of the glutamate-nitric oxide-cGMP pathway by metabotropic glutamate receptor 5 and low and high affinity AMPA receptors in cerebellum in vivo. Neurochem Int 2012; 61:63-71. [PMID: 22521775 DOI: 10.1016/j.neuint.2012.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 03/27/2012] [Accepted: 04/05/2012] [Indexed: 01/06/2023]
Abstract
Previous studies show that chronic hyperammonemia impairs learning ability of rats by impairing the glutamate-nitric oxide (NO)-cyclic guanosine mono-phosphate (cGMP) pathway in cerebellum. Three types of glutamate receptors cooperate in modulating the NO-cGMP pathway: metabotropic glutamate receptor 5 (mGluR5), (RS)-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-d-aspartic acid (NMDA) receptors. The aim of this work was to assess whether hyperammonemia alters the modulation of this pathway by mGluR5 and AMPA receptors in cerebellum in vivo. The results support that in control rats: (1) low AMPA concentrations (0.1mM) activate nearly completely Ca(2+)-permeable (glutamate receptor subunit 2 (GluR2)-lacking) AMPA receptors and the NO-cGMP pathway; (2) higher AMPA concentrations (0.3 mM) also activate Ca(2+)-impermeable (GluR2-containing) AMPA receptors, leading to activation of NMDA receptors and of NO-cGMP pathway. Moreover, the data support that chronic hyperammonemia: (1) reduces glutamate release and activation of the glutamate-NO-cGMP pathway by activation of mGluR5; (2) strongly reduces the direct activation by AMPA receptors of the NO-cGMP pathway, likely due to reduced entry of Ca(2+) through GluR2-lacking, high affinity AMPA receptors; (3) strongly increases the indirect activation of the NO-cGMP pathway by high affinity AMPA receptors, likely due to increased entry of Na(+) through GluR2-lacking AMPA receptors and NMDA receptors activation; (4) reduces the indirect activation of the NO-cGMP pathway by low affinity AMPA receptors, likely due to reduced activation of NMDA receptors.
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Affiliation(s)
- Andrea Cabrera-Pastor
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Av. Autopista del Saler, 16, 46012 Valencia, Spain.
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Raimondo F, Salemi C, Chinello C, Fumagalli D, Morosi L, Rocco F, Ferrero S, Perego R, Bianchi C, Sarto C, Pitto M, Brambilla P, Magni F. Proteomic analysis in clear cell renal cell carcinoma: identification of differentially expressed protein by 2-D DIGE. MOLECULAR BIOSYSTEMS 2012; 8:1040-51. [PMID: 22315040 DOI: 10.1039/c2mb05390j] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Renal cell carcinoma (RCC), the most common neoplasm affecting the adult kidney, is characterised by heterogeneity of histological subtypes, drug resistance, and absence of molecular markers. Two-dimensional difference gel electrophoresis (2-D DIGE) technology in combination with mass spectrometry (MS) was applied to detect differentially expressed proteins in 20 pairs of RCC tissues and matched adjacent normal kidney cortex (ANK), in order to search for RCC markers. After gel analysis by DeCyder 6.5 and EDA software, differentially expressed protein spots were excised from Deep Purple stained preparative 2DE gel. A total of 100 proteins were identified by MS out of 2500 spots, 23 and 77 of these were, respectively, over- and down-expressed in RCC. The Principal Component Analysis applied to gels and protein spots exactly separated the two sample classes in two groups: RCC and ANK. Moreover, some spots, including ANXA2, PPIA, FABP7 and LEG1, resulted highly differential. The DIGE data were also confirmed by immunoblotting analysis for these proteins. In conclusion, we suggest that applying 2-D DIGE to RCC may provide the basis for a better molecular characterization and for the discovery of candidate biomarkers.
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Affiliation(s)
- Francesca Raimondo
- Department of Experimental Medicine, Univ. of Milano-Bicocca, Via Cadore 48, 20052 Monza, Italy
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Farina F, Sancini G, Mantecca P, Gallinotti D, Camatini M, Palestini P. The acute toxic effects of particulate matter in mouse lung are related to size and season of collection. Toxicol Lett 2011; 202:209-17. [DOI: 10.1016/j.toxlet.2011.01.031] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 01/27/2011] [Accepted: 01/31/2011] [Indexed: 11/26/2022]
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Yevseyenkov VV, Das S, Lin D, Willard L, Davidson H, Sitaramayya A, Giblin FJ, Dang L, Takemoto DJ. Loss of protein kinase Cgamma in knockout mice and increased retinal sensitivity to hyperbaric oxygen. ACTA ACUST UNITED AC 2009; 127:500-6. [PMID: 19365031 DOI: 10.1001/archophthalmol.2009.31] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To determine if loss of protein kinase Cgamma (PKCgamma) results in increased structural damage to the retina by hyperbaric oxygen (HBO), a treatment used for several ocular disorders. METHODS Six-week-old mice were exposed in vivo to 100% HBO 3 times a week for 8 weeks. Eyes were dissected, fixed, embedded in Epon, sectioned, stained with toluidine blue O, and examined by light microscopy. RESULTS The thicknesses of the inner nuclear and ganglion cell layers were increased. Destruction of the outer plexiform layer was observed in the retinas of the PKCgamma-knockout mice relative to control mice. Exposure to HBO caused significant degradation of the retina in knockout mice compared with control mice. Damage to the outer segments of the photoreceptor layer and ganglion cell layer was apparent in central retinas of HBO-treated knockout mice. CONCLUSIONS Protein kinase Cgamma-knockout mice had increased retinal sensitivity to HBO. Results demonstrate that PKCgamma protects retinas from HBO damage. CLINICAL RELEVANCE Care should be taken in treating patients with HBO, particularly if they have a genetic disease, such as spinocerebellar ataxia type 14, a condition in which the PKCgamma is mutated and nonfunctional.
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Affiliation(s)
- Vladimir V Yevseyenkov
- Department of Biochemistry, 141 Chalmers Hall, Kansas State University, Manhattan, Kansas 66506, USA
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Chronic NMDA administration increases neuroinflammatory markers in rat frontal cortex: cross-talk between excitotoxicity and neuroinflammation. Neurochem Res 2008; 33:2318-23. [PMID: 18500552 DOI: 10.1007/s11064-008-9731-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Accepted: 04/25/2008] [Indexed: 10/22/2022]
Abstract
Chronic N-Methyl-D: -aspartate (NMDA) administration, a model of excitotoxicity, and chronic intracerebroventricular lipopolysaccharide infusion, a model of neuroinflammation, are reported to upregulate arachidonic acid incorporation and turnover in rat brain phospholipids as well as enzymes involved in arachidonic acid metabolism. This suggests cross-talk between signaling pathways of excitotoxicity and of neuroinflammation, involving arachidonic acid. To test whether chronic NMDA administrations to rats can upregulate brain markers of neuroinflammation, NMDA (25 mg/kg i.p.) or vehicle (1 ml saline/kg i.p.) was administered daily to adult male rats for 21 days. Protein and mRNA levels of cytokines and other inflammatory markers were measured in the frontal cortex using immunoblot and real-time PCR. Compared with chronic vehicle, chronic NMDA significantly increased protein and mRNA levels of interleukin-1beta, tumor necrosis factor alpha, glial fibrillary acidic protein and inducible nitric oxide synthase. Chronic NMDA receptor overactivation results in increased levels of neuroinflammatory markers in the rat frontal cortex, consistent with cross-talk between excitotoxicity and neuroinflammation. As both processes have been reported in a number of human brain diseases, NMDA receptor inhibitors might be of use in treating neuroinflammation in these diseases.
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Botto L, Masserini M, Palestini P. Changes in the composition of detergent-resistant membrane domains of cultured neurons following protein kinase C activation. J Neurosci Res 2007; 85:443-50. [PMID: 17086551 DOI: 10.1002/jnr.21111] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Changes in the composition of cell fractions, and in particular of detergent-resistant membranes (DRM) isolated from cultured rat cerebellar granule cells, were taken as possible changes in lipid raft composition during a signal transduction event. After activation of protein kinase C (PKC) with phorbol esters (PMA) or glutamate, the content of PKC and of proteins highly enriched (GAP43, Fyn, and PrP(c)) or not (MARCKS) in DRM was followed. PKC activation strongly increased its association with membranes (from 2% to 75%), causing its enrichment within DRM; the substrate GAP43, enriched in DRM, remained membrane associated, but its proportion in DRM dramatically decreased (from about 40% to 2.5%), suggesting its shift from raft to nonraft membranes, possibly as a consequence of phosphorylation by PKC. The distribution of Fyn and PrP(c) (DRM-enriched) and of MARCKS (present mainly outside DRM) did not change. PKC activation was followed by an increase of GAP43 and MARCKS phosphorylation (about 7- and 8-fold, respectively). Noteworthy was that, after cell treatment with the lipid raft-disrupting drug methyl-beta-cyclodextrin, PKC activation occurred normally, followed by MARCKS phosphorylation, but GAP43 phosphorylation did not occur. Taken altogether, these data suggest that the integrity of lipid rafts is necessary for PKC to affect GAP43 and catalyze its phosphorylation.
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Affiliation(s)
- L Botto
- Department of Experimental Medicine (DIMS), Medical School, University of Milano-Bicocca, Monza, Italy
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Sánchez-Pérez AM, Felipo V. Chronic exposure to ammonia alters basal and NMDA-induced phosphorylation of NMDA receptor-subunit NR1. Neuroscience 2006; 140:1239-44. [PMID: 16678351 DOI: 10.1016/j.neuroscience.2006.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 02/23/2006] [Accepted: 03/03/2006] [Indexed: 10/24/2022]
Abstract
Hyperammonemia is responsible for many of the neurological alterations in patients with hepatic encephalopathy by mechanisms that remain unclear. Hyperammonemia alters phosphorylation of brain protein kinase C substrates and impairs N-methyl-d-aspartate (NMDA) receptor-associated signal transduction. The aim of this work was to analyze, in rat cerebellar neurons in culture, the effects of ammonia exposure on NMDA receptor phosphorylation, MK801 binding and surface expression. Ammonia reduces MK801 binding to NMDA receptors and the surface expression of the NR1 and NR2A subunits. As phosphorylation of serines in the NR1 C1 cassette has been implied in receptor trafficking, we assessed whether hyperammonemia alters phosphorylation of these serines. Basal phosphorylation of serines 890, 896 and 897 was increased in neurons exposed to ammonia, while NMDA-induced phosphorylation of S896 and S897 was reduced. Exposure to ammonia also increased basal phosphorylation of Akt but reduced NMDA and BDNF stimulation of Akt phosphorylation. These results suggest that alterations in receptor surface expression and possibly the phosphorylation state of the NR1 subunit of NMDA receptors may contribute to the impairment by ammonia of signal transduction pathways modulated by NMDA receptors.
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Affiliation(s)
- A M Sánchez-Pérez
- Laboratory of Neurobiology, Centro de Investigacion Príncipe Felipe, Fundación de la C.V. Centro de Investigación Príncipe Felipe, Avda Autopista del Saler, 16, 46013 Valencia, Spain
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Ishikawa M, Matsushita Y, Abe K, Utsunomiya I, Hoshi K, Quock RM, Taguchi K. Involvement of brain protein kinase C in nitrous oxide-induced antinociception in mice. Neuroscience 2006; 140:227-33. [PMID: 16533570 DOI: 10.1016/j.neuroscience.2006.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2005] [Revised: 12/23/2005] [Accepted: 02/01/2006] [Indexed: 11/22/2022]
Abstract
Exposure of mice to the anesthetic gas nitrous oxide (N(2)O) produces a marked antinociceptive effect. Protein kinase C is a key regulatory enzyme that may be targeted by general anesthetics. However, a relationship between N(2)O-induced antinociception and protein kinase C has yet to be established. The present study was conducted to identify whether protein kinase C might influence N(2)O-induced antinociception in mice. Regular exposure (11 min) to N(2)O produced concentration-dependent antinociception in mice, as determined using the abdominal constriction test. N(2)O-induced antinociception was attenuated by i.c.v. pretreatment with phorbol 12,13-dibutyrate, a protein kinase C activator. This phorbol 12,13-dibutyrate antagonism of N(2)O-induced antinociception was reversed by i.c.v. pretreatment with calphostin C, a protein kinase C inhibitor. Long-term exposure (41 min in total, including 30 min prior to, and 11 min of analgesic testing) to 70% N(2)O produced reduced analgesic effects, compared with regular exposure to 70% N(2)O, thus indicating acute tolerance to N(2)O-induced antinociception. However, mice pretreated with calphostin C, chelerythrine, which is another protein kinase C inhibitor, and phorbol 12,13-dibutyrate, did not develop acute tolerance. Regarding activation of protein kinase C, regular exposure to 70% N(2)O did not increase protein kinase C within the membrane fraction of brain tissue, as determined by immunoblot analysis, but long-term exposure to 70% N(2)O did. The i.c.v. pretreatment with calphostin C and phorbol 12,13-dibutyrate prevented the increase in protein kinase C observed with long-term exposure to 70% N(2)O. These results suggest that brain protein kinase C negatively regulates the antinociceptive effect of N(2)O, and that activation of brain protein kinase C is related to the development of acute tolerance to N(2)O-induced antinociception in mice.
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Affiliation(s)
- M Ishikawa
- Department of Pharmacotherapeutics, Showa Pharmaceutical University, P.O. Box 3-3165, Higashitamagawagakuen, Tokyo 194-8543, Japan
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Funchal C, Zamoner A, dos Santos AQ, Loureiro SO, Wajner M, Pessoa-Pureur R. Alpha-ketoisocaproic acid increases phosphorylation of intermediate filament proteins from rat cerebral cortex by mechanisms involving Ca2+ and cAMP. Neurochem Res 2006; 30:1139-46. [PMID: 16292507 DOI: 10.1007/s11064-005-7709-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2005] [Indexed: 10/25/2022]
Abstract
We have previously described that alpha-ketoisocaproic acid (KIC), the main metabolite accumulating in maple syrup urine disease (MSUD), increased the in vitro phosphorylation of cytoskeletal proteins in cerebral cortex of 17- and 21-day-old rats through NMDA glutamatergic receptors. In the present study we investigated the protein kinases involved in the effects of KIC on the phosphorylating system associated with the cytoskeletal fraction and provided an insight on the mechanisms involved in such effects. Results showed that 1 mM KIC increased the in vitro incorporation of 32P into intermediate filament (IF) proteins in slices of 21-day-old rats at shorter incubation times (5 min) than previously reported. Furthermore, this effect was prevented by 10 microM KN-93 and 10 microM H-89, indicating that KIC treatment increased Ca2+/calmodulin- (PKCaMII) and cAMP- (PKA) dependent protein kinases activities, respectively. Nifedipine (100 microM), a blocker of voltage-dependent calcium channels (VDCC), DL-AP5 (100 microM), a NMDA glutamate receptor antagonist and BAPTA-AM (50 microM), a potent intracellular Ca2+ chelator, were also able to prevent KIC-induced increase of in vitro phosphorylation of IF proteins. In addition, KIC treatment was able to significantly increase the intracellular cAMP levels. This data support the view that KIC increased the activity of the second messenger-dependent protein kinases PKCaMII and PKA through intracellular Ca2+ levels. Considering that hyperphosphorylation of cytoskeletal proteins is related to neurodegeneration it is presumed that the Ca2+-dependent hyperphosphorylation of IF proteins caused by KIC may be involved to the neuropathology of MSUD patients.
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Affiliation(s)
- Cláudia Funchal
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600 anexo, 90035-003, Porto Alegre, RS, Brasil
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Cauli O, Llansola M, Rodrigo R, El Mlili N, Errami M, Felipo V. Altered modulation of motor activity by group I metabotropic glutamate receptors in the nucleus accumbens in hyperammonemic rats. Metab Brain Dis 2005; 20:347-58. [PMID: 16382345 DOI: 10.1007/s11011-005-7918-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
One of the neurological complications in hepatic encephalopathy is the impairment of motor coordination and function. Clinical signs of basal ganglia, cortico-spinal and cerebellar dysfunction have been commonly detected in these patients. We are studying the molecular bases of the alterations in motor coordination and function in hepatic encephalopathy. Hyperammonemia is considered the main factor responsible for the neurological alterations in patients with hepatic encephalopathy. Activation of metabotropic glutamate receptors (mGluRs) in the nucleus accumbens (NAcc) induces locomotion in rats. Asa first step in our studies on the alterations in motor co-ordination and function in hyperammonemia and hepatic encephalopathy we studied whether the control of motor function by mGluRs in the NAcc is altered in hyperammonemic rats. The locomotor activity induced by injection into the nucleus accumbens (NAcc) of DHPG, an agonist of group I mGluRs was significantly increased in hyperammonemic rats. Injection of DHPG increased extracellular dopamine but not glutamate in the NAcc of control rats. In hyperammonemic rats DHPG-induced increase in dopamine was significantly reduced, and extracellular glutamate increased 6-fold. The content of mGluR 1 but not mGluR 5, is increased in the NAcc of hyperammonemic rats. Blockade of mGluR 1 completely prevented motor and neurochemical effects induced by DHPG. These results show that modulation of both motor function and extracellular concentration of neurotransmitters by mGluRs in the NAcc is altered in hyperammonemia. This may contribute to the alterations in motor function in hepatic encephalopathy.
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Affiliation(s)
- Omar Cauli
- Laboratory of Neurobiology, Fundación Valenciana de Investigaciones Biomédicas, Valencia, Spain.
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