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Li Y, Li D, Liu Y, Wang S, Sun M, Zhang Z, Zheng X, Li J, Li Y. The positive feedback loop of NHE1-ERK phosphorylation mediated by BRAF V600E mutation contributes to tumorigenesis and development of glioblastoma. Biochem Biophys Res Commun 2022; 588:1-7. [PMID: 34933181 DOI: 10.1016/j.bbrc.2021.11.104] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/30/2021] [Indexed: 01/13/2023]
Abstract
The v-raf murine sarcoma viral oncogene homolog B1 (BRAF) activating mutation V600E (BRAFV600E) is involved in glioblastoma multiforme (GBM). Na/H exchanger 1 (NHE1), a main pH regulator affecting cell microenvironment, is hyper-expressed in GBM. However, the relationship between BRAFV600E signal pathway and NHE1 in GMB cells remains unclear. This study found that NHE1 was a downstream target of BRAFV600E and an upstream factor of extracellular signal-regulated kinase (ERK). In addition, there was a positive feedback loop between NHE1-ERK phosphorylation under regulation of BRAFV600E mutation contributing to the proliferation and invasion of GBM cells. Moreover, the proliferation and invasion abilities of BRAFV600E-mutant and BRAF wild type GBM cells were all suppressed by the NHE1 inhibitor, BRAFV600E inhibitor and combination of them. The inhibitory effect of combination of the two inhibitors was better than each single drug both in vitro and in vivo. Combination of BRAFV600E and NHE1 inhibitors could be considered as a new therapeutic regimen for GBM, especially for GBM with BRAFV600E.
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Affiliation(s)
- Yuhui Li
- Department of Neurosurgery, Tangshan People's Hospital, Tangshan, Hebei, 063001, PR China
| | - Dan Li
- The Cancer Institute, Tangshan People's Hospital, Tangshan, Hebei, 063001, PR China
| | - Yankun Liu
- The Cancer Institute, Tangshan People's Hospital, Tangshan, Hebei, 063001, PR China
| | - Shuqing Wang
- Hospital of North China University of Science and Technology, Tangshan, Hebei, 063210, PR China
| | - Mingyang Sun
- Department of Neurosurgery, Tangshan People's Hospital, Tangshan, Hebei, 063001, PR China
| | - Zhongyuan Zhang
- Department of Neurosurgery, Zunhua People's Hospital, Zunhua, Hebei, 064200, PR China
| | - Xuan Zheng
- Nuclear Medicine Clinical Laboratory, Tangshan People's Hospital, Tangshan, Hebei, 063001, PR China
| | - Jingwu Li
- The Cancer Institute, Tangshan People's Hospital, Tangshan, Hebei, 063001, PR China.
| | - Yufeng Li
- The Cancer Institute, Tangshan People's Hospital, Tangshan, Hebei, 063001, PR China.
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2
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Gu Q, Cuevas E, Raymick J, Kanungo J, Sarkar S. Downregulation of 14-3-3 Proteins in Alzheimer’s Disease. Mol Neurobiol 2019; 57:32-40. [DOI: 10.1007/s12035-019-01754-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 08/29/2019] [Indexed: 01/03/2023]
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3
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Smani D, Sarkar S, Raymick J, Kanungo J, Paule MG, Gu Q. Downregulation of 14-3-3 Proteins in a Kainic Acid-Induced Neurotoxicity Model. Mol Neurobiol 2019; 55:122-129. [PMID: 28840498 DOI: 10.1007/s12035-017-0724-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The 14-3-3 proteins are among the most abundant proteins expressed in the brain, comprising about 1% of the total amount of soluble brain proteins. Through phosphoserine- and phosphothreonine-binding motifs, 14-3-3 proteins regulate many signaling proteins and cellular processes including cell death. In the present study, we utilized a well-known kainic acid (KA)-induced excitotoxicity rat model and examined the expression of 14-3-3 and its isoforms in the frontal cortex of KA-treated and control animals. Among the different 14-3-3 isoforms, abundant levels of eta and tau were detected in the frontal cortex, followed by sigma, epsilon, and gamma, while the expression levels of alpha/beta and zeta/delta isoforms were low. Compared to the control animals, KA treatment induced a significant downregulation of the overall 14-3-3 protein level as well as the levels of the abundant isoforms eta, tau, epsilon, and gamma. We also investigated two 14-3-3-interacting proteins that are involved in the cell death process: Bcl-2-associated X (BAX) and extracellular signal-regulated kinase (ERK). Both BAX and phosphorylated ERK showed increased levels following KA treatment. Together, these findings demonstrate an abundance of several 14-3-3 isoforms in the frontal cortex and that KA treatment can cause a downregulation of 14-3-3 expression and an upregulation of 14-3-3-interacting proteins BAX and phospho-ERK. Thus, downregulation of 14-3-3 proteins could be one of the early molecular events associated with excitotoxicity. This could lead to subsequent upregulation of 14-3-3-binding proteins such as BAX and phospho-ERK that contribute to further downstream apoptosis processes, eventually leading to cell death. Maintaining sufficient levels of 14-3-3 expression and function may become a target of therapeutic intervention for excitotoxicity-induced neurodegeneration.
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Affiliation(s)
- Danyal Smani
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, Jefferson, AR, 72079, USA
| | - Sumit Sarkar
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, Jefferson, AR, 72079, USA
| | - James Raymick
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, Jefferson, AR, 72079, USA
| | - Jyotshna Kanungo
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, Jefferson, AR, 72079, USA
| | - Merle G Paule
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, Jefferson, AR, 72079, USA
| | - Qiang Gu
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Rd, Jefferson, AR, 72079, USA.
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Heise C, Preuss JM, Schroeder JC, Battaglia CR, Kolibius J, Schmid R, Kreutz MR, Kas MJH, Burbach JPH, Boeckers TM. Heterogeneity of Cell Surface Glutamate and GABA Receptor Expression in Shank and CNTN4 Autism Mouse Models. Front Mol Neurosci 2018; 11:212. [PMID: 29970989 PMCID: PMC6018460 DOI: 10.3389/fnmol.2018.00212] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/30/2018] [Indexed: 12/21/2022] Open
Abstract
Autism spectrum disorder (ASD) refers to a large set of neurodevelopmental disorders, which have in common both repetitive behavior and abnormalities in social interactions and communication. Interestingly, most forms of ASD have a strong genetic contribution. However, the molecular underpinnings of this disorder remain elusive. The SHANK3 gene (and to a lesser degree SHANK2) which encode for the postsynaptic density (PSD) proteins SHANK3/SHANK2 and the CONTACTIN 4 gene which encodes for the neuronal glycoprotein CONTACTIN4 (CNTN4) exhibit mutated variants which are associated with ASD. Like many of the other genes associated with ASD, both SHANKs and CNTN4 affect synapse formation and function and are therefore related to the proper development and signaling capability of excitatory and inhibitory neuronal networks in the adult mammal brain. In this study, we used mutant/knock-out mice of Shank2 (Shank2−/−), Shank3 (Shank3αβ−/−), and Cntn4 (Cntn4−/−) as ASD-models to explore whether these mice share a molecular signature in glutamatergic and GABAergic synaptic transmission in ASD-related brain regions. Using a biotinylation assay and subsequent western blotting we focused our analysis on cell surface expression of several ionotropic glutamate and GABA receptor subunits: GluA1, GluA2, and GluN1 were analyzed for excitatory synaptic transmission, and the α1 subunit of the GABAA receptor was analyzed for inhibitory synaptic transmission. We found that both Shank2−/− and Shank3αβ−/− mice exhibit reduced levels of several cell surface glutamate receptors in the analyzed brain regions—especially in the striatum and thalamus—when compared to wildtype controls. Interestingly, even though Cntn4−/− mice also show reduced levels of some cell surface glutamate receptors in the cortex and hippocampus, increased levels of cell surface glutamate receptors were found in the striatum. Moreover, Cntn4−/− mice do not only show brain region-specific alterations in cell surface glutamate receptors but also a downregulation of cell surface GABA receptors in several of the analyzed brain regions. The results of this study suggest that even though mutations in defined genes can be associated with ASD this does not necessarily result in a common molecular phenotype in surface expression of glutamatergic and GABAergic receptor subunits in defined brain regions.
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Affiliation(s)
- Christopher Heise
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany.,RG Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Jonathan M Preuss
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Jan C Schroeder
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | | | - Jonas Kolibius
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Rebecca Schmid
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Michael R Kreutz
- RG Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Martien J H Kas
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands.,Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - J Peter H Burbach
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, Netherlands
| | - Tobias M Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
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Tolö J, Taschenberger G, Leite K, Stahlberg MA, Spehlbrink G, Kues J, Munari F, Capaldi S, Becker S, Zweckstetter M, Dean C, Bähr M, Kügler S. Pathophysiological Consequences of Neuronal α-Synuclein Overexpression: Impacts on Ion Homeostasis, Stress Signaling, Mitochondrial Integrity, and Electrical Activity. Front Mol Neurosci 2018; 11:49. [PMID: 29563864 PMCID: PMC5845890 DOI: 10.3389/fnmol.2018.00049] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 02/06/2018] [Indexed: 11/13/2022] Open
Abstract
α-Synuclein (α-Syn) is intimately linked to the etiology of Parkinson's Disease, as mutations and even subtle increases in gene dosage result in early onset of the disease. However, how this protein causes neuronal dysfunction and neurodegeneration is incompletely understood. We thus examined a comprehensive range of physiological parameters in cultured rat primary neurons overexpressing α-Syn at levels causing a slowly progressive neurodegeneration. In contradiction to earlier reports from non-neuronal assay systems we demonstrate that α-Syn does not interfere with essential ion handling capacities, mitochondrial capability of ATP production or basic electro-physiological properties like resting membrane potential or the general ability to generate action potentials. α-Syn also does not activate canonical stress kinase Signaling converging on SAPK/Jun, p38 MAPK or Erk kinases. Causative for α-Syn-induced neurodegeneration are mitochondrial thiol oxidation and activation of caspases downstream of mitochondrial outer membrane permeabilization, leading to apoptosis-like cell death execution with some unusual aspects. We also aimed to elucidate neuroprotective strategies counteracting the pathophysiological processes caused by α-Syn. Neurotrophic factors, calpain inhibition and increased lysosomal protease capacity showed no protective effects against α-Syn overexpression. In contrast, the major watchdog of outer mitochondrial membrane integrity, Bcl-Xl, was capable of almost completely preventing neuron death, but did not prevent mitochondrial thiol oxidation. Importantly, independent from the quite mono-causal induction of neurotoxicity, α-Syn causes diminished excitability of neurons by external stimuli and robust impairments in endogenous neuronal network activity by decreasing the frequency of action potentials generated without external stimulation. This latter finding suggests that α-Syn can induce neuronal dysfunction independent from its induction of neurotoxicity and might serve as an explanation for functional deficits that precede neuronal cell loss in synucleopathies like Parkinson's disease or dementia with Lewy bodies.
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Affiliation(s)
- Johan Tolö
- Department of Physiology, The Sahlgrenska Academy at Gothenburg University, Gothenburg, Sweden
| | - Grit Taschenberger
- Department of Neurology, University Medical Center Goettingen, Göttingen, Germany.,Center Nanoscale Microscopy and Physiology of the Brain, Göttingen, Germany
| | - Kristian Leite
- Department of Neurology, University Medical Center Goettingen, Göttingen, Germany
| | - Markus A Stahlberg
- European Neuroscience Institute, Department of Transsynaptic Signaling, Göttingen, Germany
| | - Gesche Spehlbrink
- Department of Neurology, University Medical Center Goettingen, Göttingen, Germany
| | - Janina Kues
- Department of Neurology, University Medical Center Goettingen, Göttingen, Germany
| | - Francesca Munari
- German Center for Neurodegenerative Diseases, Göttingen, Germany.,Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Stefano Capaldi
- Biocrystallography Laboratory, Department of Biotechnology, University of Verona, Verona, Italy
| | - Stefan Becker
- Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Markus Zweckstetter
- Department of Neurology, University Medical Center Goettingen, Göttingen, Germany.,Center Nanoscale Microscopy and Physiology of the Brain, Göttingen, Germany.,German Center for Neurodegenerative Diseases, Göttingen, Germany.,Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Camin Dean
- Center Nanoscale Microscopy and Physiology of the Brain, Göttingen, Germany.,European Neuroscience Institute, Department of Transsynaptic Signaling, Göttingen, Germany
| | - Mathias Bähr
- Department of Neurology, University Medical Center Goettingen, Göttingen, Germany.,Center Nanoscale Microscopy and Physiology of the Brain, Göttingen, Germany
| | - Sebastian Kügler
- Department of Neurology, University Medical Center Goettingen, Göttingen, Germany.,Center Nanoscale Microscopy and Physiology of the Brain, Göttingen, Germany
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Transglutaminase is a therapeutic target for oxidative stress, excitotoxicity and stroke: a new epigenetic kid on the CNS block. J Cereb Blood Flow Metab 2013; 33:809-18. [PMID: 23571278 PMCID: PMC3677119 DOI: 10.1038/jcbfm.2013.53] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Transglutaminases (TGs) are multifunctional, calcium-dependent enzymes that have been recently implicated in stroke pathophysiology. Classically, these enzymes are thought to participate in cell injury and death in chronic neurodegenerative conditions via their ability to catalyze covalent, nondegradable crosslinks between proteins or to incorporate polyamines into protein substrates. Accumulating lines of inquiry indicate that specific TG isoforms can shuttle into the nucleus when they sense pathologic changes in calcium or oxidative stress, bind to chromatin and thereby transduce these changes into transcriptional repression of genes involved in metabolic or oxidant adaptation. Here, we review the evidence that supports principally a role for one isoform of this family, TG2, in cell injury and death associated with hemorrhagic or ischemic stroke. We also outline an evolving model in which TG2 is a critical mediator between pathologic signaling and epigenetic modifications that lead to gene repression. Accordingly, the salutary effects of TG inhibitors in stroke may derive from their ability to restore homeostasis by removing inappropriate deactivation of adaptive genetic programs by oxidative stress or extrasynaptic glutamate receptor signaling.
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7
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Transglutaminase inhibition protects against oxidative stress-induced neuronal death downstream of pathological ERK activation. J Neurosci 2012; 32:6561-9. [PMID: 22573678 DOI: 10.1523/jneurosci.3353-11.2012] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Molecular deletion of transglutaminase 2 (TG2) has been shown to improve function and survival in a host of neurological conditions including stroke, Huntington's disease, and Parkinson's disease. However, unifying schemes by which these cross-linking or polyaminating enzymes participate broadly in neuronal death have yet to be presented. Unexpectedly, we found that in addition to TG2, TG1 gene expression level is significantly induced following stroke in vivo or due to oxidative stress in vitro. Forced expression of TG1 or TG2 proteins is sufficient to induce neuronal death in Rattus norvegicus cortical neurons in vitro. Accordingly, molecular deletion of TG2 alone is insufficient to protect Mus musculus neurons from oxidative death. By contrast, structurally diverse inhibitors used at concentrations that inhibit TG1 and TG2 simultaneously are neuroprotective. These small molecules inhibit increases in neuronal transamidating activity induced by oxidative stress; they also protect neurons downstream of pathological ERK activation when added well after the onset of the death stimulus. Together, these studies suggest that multiple TG isoforms, not only TG2, participate in oxidative stress-induced cell death signaling; and that isoform nonselective inhibitors of TG will be most efficacious in combating oxidative death in neurological disorders.
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Karki P, Li X, Schrama D, Fliegel L. B-Raf associates with and activates the NHE1 isoform of the Na+/H+ exchanger. J Biol Chem 2011; 286:13096-105. [PMID: 21345796 PMCID: PMC3075656 DOI: 10.1074/jbc.m110.165134] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 02/03/2011] [Indexed: 01/03/2023] Open
Abstract
The serine/threonine kinase B-Raf is the second most frequently occurring human oncogene after Ras. Mutations of B-Raf occur with the highest incidences in melanoma, and the most common mutant, V600E, renders B-Raf constitutively active. The sodium proton exchanger isoform 1 (NHE1) is a ubiquitously expressed plasma membrane protein responsible for regulating intracellular pH, cell volume, cell migration, and proliferation. A screen of protein kinases that bind to NHE1 revealed that B-Raf bound to the cytosolic regulatory tail of NHE1. Immunoprecipitation of NHE1 from HeLa and HEK cells confirmed the association of B-Raf with NHE1 in vivo. The expressed and purified C-terminal 182 amino acids of the NHE1 protein were also shown to associate with B-Raf protein in vitro. Because treatment with the kinase inhibitor sorafenib decreased NHE1 activity in HeLa and HEK cells, we examined the role of B-Raf in regulating NHE1 in malignant melanoma cells. Melanoma cells with the B-Raf(V600E) mutation demonstrated increased resting intracellular pH that was dependent on elevated NHE1 activity. NHE1 activity after an acute acid load was also elevated in these cell lines. Moreover, inhibition of B-Raf activity by either sorafenib, PLX4720, or siRNA reduction of B-Raf levels abolished ERK phosphorylation and decreased NHE1 activity. These results demonstrate that B-Raf associates with and stimulates NHE1 activity and that B-Raf(V600E) also increases NHE1 activity that raises intracellular pH.
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Affiliation(s)
- Pratap Karki
- From the Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada and
| | - Xiuju Li
- From the Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada and
| | - David Schrama
- the Division of Dermatology, Medical University of Graz, 8036 Graz, Austria
| | - Larry Fliegel
- From the Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada and
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