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Li N, Liao S, Liu L, Wang X, Liang Z, Liu X, Song Y, Zhao S, Wu X, Tian Y, Xu X, Yang Y, Liu Q. Pleiotropic role of endoplasmic reticulum stress in the protection of psoralidin against sepsis-associated encephalopathy. Free Radic Biol Med 2024; 221:203-214. [PMID: 38788982 DOI: 10.1016/j.freeradbiomed.2024.05.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/11/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024]
Abstract
Sepsis-associated encephalopathy (SAE) is a severe complication that affects the central nervous system and is a leading cause of increased morbidity and mortality in intensive care units. Psoralidin (PSO), a coumarin compound isolated from the traditional Chinese medicine Psoralea corylifolia L., can penetrate the blood-brain barrier and has various pharmacological activities, including anti-inflammation, anti-oxidation and anti-depression. This study aims to explore whether PSO alleviates SAE and delve into the underlying mechanisms. We found that PSO treatment significantly reduced sepsis scores, aspartate transaminase (AST) and aspartate transaminase (LDH), while increased anal temperature and neurological scores in CLP-injured mice. Moreover, PSO treatment ameliorated sepsis-associated cognitive impairment, mood, anxiety disorders, inhibited inflammatory responses, as well as attenuated endoplasmic reticulum stress (ERS). These results were also validated in vitro experiments, PSO treatment reduced ROS, inflammation response, and attenuated ERS in LPS-injured N2a cells. Importantly, tunicamycin (TUN), as ERS agonist, significantly reversed the protective effect of PSO on LPS-injured N2a cells, as evidenced by increased expression levels of IL-6, NLRP3, CHOP, and ATF6. Likewise, ATF6 overexpression also reversed the protective effect of PSO. In conclusion, these results confirmed that PSO has a protective effect on SAE, which was largely attributed to neuroinflammation and ERS. These findings provide new insights into the neuroprotective role of PSO and suggest that PSO is a new therapeutic intervention of SAE.
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Affiliation(s)
- Ning Li
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, 710069, China
| | - Sha Liao
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, 710069, China
| | - Lu Liu
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, 710069, China
| | - Xue Wang
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, 710061, China
| | - Zhenxing Liang
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Zhengzhou University, 1 Jianshe East, Zhengzhou, 450052, China
| | - Xiaoyi Liu
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, 710069, China
| | - Yuefei Song
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, 710069, China
| | - Shiyan Zhao
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, 710069, China
| | - Xue Wu
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, 710069, China
| | - Ye Tian
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, 710069, China
| | - Xuezeng Xu
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, 127 Changle West Road, Xi'an, 710032, China
| | - Yang Yang
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, 710069, China.
| | - Qiong Liu
- Xi'an Key Laboratory of Innovative Drug Research for Heart Failure, Faculty of Life Sciences and Medicine, Northwest University, 229 Taibai North Road, Xi'an, 710069, China.
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Popova EY, Kawasawa YI, Leung M, Barnstable CJ. Temporal changes in mouse hippocampus transcriptome after pilocarpine-induced seizures. Front Neurosci 2024; 18:1384805. [PMID: 39040630 PMCID: PMC11260795 DOI: 10.3389/fnins.2024.1384805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 06/07/2024] [Indexed: 07/24/2024] Open
Abstract
Introduction Status epilepticus (SE) is a seizure lasting more than 5 min that can have lethal consequences or lead to various neurological disorders, including epilepsy. Using a pilocarpine-induced SE model in mice we investigated temporal changes in the hippocampal transcriptome. Methods We performed mRNA-seq and microRNA-seq analyses at various times after drug treatment. Results At 1 h after the start of seizures, hippocampal cells upregulated transcription of immediate early genes and genes involved in the IGF-1, ERK/MAPK and RNA-PolII/transcription pathways. At 8 h, we observed changes in the expression of genes associated with oxidative stress, overall transcription downregulation, particularly for genes related to mitochondrial structure and function, initiation of a stress response through regulation of ribosome and translation/EIF2 signaling, and upregulation of an inflammatory response. During the middle of the latent period, 36 h, we identified upregulation of membrane components, cholesterol synthesis enzymes, channels, and extracellular matrix (ECM), as well as an increased inflammatory response. At the end of the latent period, 120 h, most changes in expression were in genes involved in ion transport, membrane channels, and synapses. Notably, we also elucidated the involvement of novel pathways, such as cholesterol biosynthesis pathways, iron/BMP/ferroptosis pathways, and circadian rhythms signaling in SE and epileptogenesis. Discussion These temporal changes in metabolic reactions indicate an immediate response to injury followed by recovery and regeneration. CREB was identified as the main upstream regulator. Overall, our data provide new insights into molecular functions and cellular processes involved at different stages of seizures and offer potential avenues for effective therapeutic strategies.
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Affiliation(s)
- Evgenya Y. Popova
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA, United States
- Penn State Hershey Eye Center, Hershey, PA, United States
| | - Yuka Imamura Kawasawa
- Department of Pharmacology, Penn State University College of Medicine, Hershey, PA, United States
- Center for Cancer Genomics and Precision Oncology, Wake Forest Baptist Comprehensive Cancer Center, Winston Salem, NC, United States
| | - Ming Leung
- Center for Cancer Genomics and Precision Oncology, Wake Forest Baptist Comprehensive Cancer Center, Winston Salem, NC, United States
| | - Colin J. Barnstable
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA, United States
- Penn State Hershey Eye Center, Hershey, PA, United States
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Hammer M, Krzyzaniak C, Bahramnejad E, Smelser K, Hack J, Watkins J, Ronaldson P. Sex differences in physiological response to increased neuronal excitability in a knockin mouse model of pediatric epilepsy. Clin Sci (Lond) 2024; 138:205-223. [PMID: 38348743 PMCID: PMC10881277 DOI: 10.1042/cs20231572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/01/2024] [Accepted: 02/09/2024] [Indexed: 02/22/2024]
Abstract
BACKGROUND Epilepsy is a common neurological disease; however, few if any of the currently marketed antiseizure medications prevent or cure epilepsy. Discovery of pathological processes in the early stages of epileptogenesis has been challenging given the common use of preclinical models that induce seizures in physiologically normal animals. Moreover, despite known sex dimorphism in neurological diseases, females are rarely included in preclinical epilepsy models. METHODS We characterized sex differences in mice carrying a pathogenic knockin variant (p.N1768D) in the Scn8a gene that causes spontaneous tonic-clonic seizures (TCs) at ∼3 months of age and found that heterozygous females are more resilient than males in mortality and morbidity. To investigate the cellular mechanisms that underlie female resilience, we utilized blood-brain barrier (BBB) and hippocampal transcriptomic analyses in heterozygous mice before seizure onset (pre-TC) and in mice that experienced ∼20 TCs (post-TC). RESULTS In the pre-TC latent phase, both sexes exhibited leaky BBB; however, patterns of gene expression were sexually dimorphic. Females exhibited enhanced oxidative phosphorylation and protein biogenesis, while males activated gliosis and CREB signaling. After seizure onset (chronic phase), females exhibited a metabolic switch to lipid metabolism, while males exhibited increased gliosis and BBB dysfunction and a strong activation of neuroinflammatory pathways. CONCLUSION The results underscore the central role of oxidative stress and BBB permeability in the early stages of epileptogenesis, as well as sex dimorphism in response to increasing neuronal hyperexcitability. Our results also highlight the need to include both sexes in preclinical studies to effectively translate results of drug efficacy studies.
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Affiliation(s)
- Michael F. Hammer
- BIO5 Institute, University of Arizona, Tucson, Arizona, U.S.A
- Department of Neurology, University of Arizona, Tucson, Arizona, U.S.A
| | | | - Erfan Bahramnejad
- BIO5 Institute, University of Arizona, Tucson, Arizona, U.S.A
- Department of Pharmacology, University of Arizona, Tucson, Arizona, U.S.A
| | | | - Joshua B. Hack
- BIO5 Institute, University of Arizona, Tucson, Arizona, U.S.A
| | - Joseph C. Watkins
- Department of Mathematics, University of Arizona, Tucson, Arizona, U.S.A
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4
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Ye Z, Harmon J, Ni W, Li Y, Wich D, Xu Q. The mRNA Vaccine Revolution: COVID-19 Has Launched the Future of Vaccinology. ACS NANO 2023; 17:15231-15253. [PMID: 37535899 DOI: 10.1021/acsnano.2c12584] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
During the COVID-19 pandemic, mRNA (mRNA) vaccines emerged as leading vaccine candidates in a record time. Nonreplicating mRNA (NRM) and self-amplifying mRNA (SAM) technologies have been developed into high-performing and clinically viable vaccines against a range of infectious agents, notably SARS-CoV-2. mRNA vaccines demonstrate efficient in vivo delivery, long-lasting stability, and nonexistent risk of infection. The stability and translational efficiency of in vitro transcription (IVT)-mRNA can be further increased by modulating its structural elements. In this review, we present a comprehensive overview of the recent advances, key applications, and future challenges in the field of mRNA-based vaccinology.
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Affiliation(s)
- Zhongfeng Ye
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155, United States
| | - Joseph Harmon
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155, United States
| | - Wei Ni
- Department of Medical Oncology, Dana-Farber Cancer Institute at Harvard Medical School, Boston, Massachusetts 02215, United States
| | - Yamin Li
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, New York 13210, United States
| | - Douglas Wich
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155, United States
| | - Qiaobing Xu
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155, United States
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5
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Lodes DE, Zhu J, Tsai NP. E3 ubiquitin ligase Nedd4-2 exerts neuroprotective effects during endoplasmic reticulum stress. J Neurochem 2022; 160:613-624. [PMID: 34935153 PMCID: PMC8930443 DOI: 10.1111/jnc.15567] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/02/2021] [Accepted: 12/19/2021] [Indexed: 12/22/2022]
Abstract
The neural precursor cell expressed developmentally down-regulated protein 4-like (Nedd4-2) is an E3 ubiquitin ligase critical for neurodevelopment and homeostasis of neural circuit excitability. While dysregulation of Nedd4-2 has been linked to elevated seizure susceptibility through impaired ubiquitination of multiple direct substrates, it remains largely unclear whether Nedd4-2 interconnects other cellular pathways that affect neuronal activity and seizure susceptibility. Here, we first showed that Nedd4-2 associates with the endoplasmic reticulum (ER) and regulates the expression of multiple ER-resident proteins. Furthermore, utilizing Nedd4-2 conditional knockout mice, we showed that Nedd4-2 is required for the maintenance of spontaneous neural activity and excitatory synapses following the induction of ER stress. When analyzing activation of the canonical pathways of ER stress response, we found that Nedd4-2 is required for phosphorylation of eIF2α. While phosphorylation of eIF2α has been shown to reduce seizure susceptibility, attempts to facilitate phosphorylation of eIF2α in Nedd4-2 conditional knockout mice failed to produce such a beneficial function, suggesting a role for Nedd4-2 in integrating the ER stress response to modulate seizure susceptibility. Altogether, our study demonstrates neuroprotective functions of Nedd4-2 during ER stress in neurons and could provide insight into neurological diseases in which the expression or activity of Nedd4-2 is impaired.
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Affiliation(s)
- Daphne E Lodes
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jiuhe Zhu
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Nien-Pei Tsai
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA,Correspondence: Nien-Pei Tsai, Ph.D., 407 South Goodwin Ave, Urbana, IL 61801, USA, Tel: 217-244-5620 Fax: 217-333-1133,
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6
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Gourmaud S, Shou H, Irwin DJ, Sansalone K, Jacobs LM, Lucas TH, Marsh ED, Davis KA, Jensen FE, Talos DM. Alzheimer-like amyloid and tau alterations associated with cognitive deficit in temporal lobe epilepsy. Brain 2020; 143:191-209. [PMID: 31834353 DOI: 10.1093/brain/awz381] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 10/08/2019] [Accepted: 10/17/2019] [Indexed: 01/27/2023] Open
Abstract
Temporal lobe epilepsy represents a major cause of drug-resistant epilepsy. Cognitive impairment is a frequent comorbidity, but the mechanisms are not fully elucidated. We hypothesized that the cognitive impairment in drug-resistant temporal lobe epilepsy could be due to perturbations of amyloid and tau signalling pathways related to activation of stress kinases, similar to those observed in Alzheimer's disease. We examined these pathways, as well as amyloid-β and tau pathologies in the hippocampus and temporal lobe cortex of drug-resistant temporal lobe epilepsy patients who underwent temporal lobe resection (n = 19), in comparison with age- and region-matched samples from neurologically normal autopsy cases (n = 22). Post-mortem temporal cortex samples from Alzheimer's disease patients (n = 9) were used as positive controls to validate many of the neurodegeneration-related antibodies. Western blot and immunohistochemical analysis of tissue from temporal lobe epilepsy cases revealed increased phosphorylation of full-length amyloid precursor protein and its associated neurotoxic cleavage product amyloid-β*56. Pathological phosphorylation of two distinct tau species was also increased in both regions, but increases in amyloid-β1-42 peptide, the main component of amyloid plaques, were restricted to the hippocampus. Furthermore, several major stress kinases involved in the development of Alzheimer's disease pathology were significantly activated in temporal lobe epilepsy brain samples, including the c-Jun N-terminal kinase and the protein kinase R-like endoplasmic reticulum kinase. In temporal lobe epilepsy cases, hippocampal levels of phosphorylated amyloid precursor protein, its pro-amyloidogenic processing enzyme beta-site amyloid precursor protein cleaving enzyme 1, and both total and hyperphosphorylated tau expression, correlated with impaired preoperative executive function. Our study suggests that neurodegenerative and stress-related processes common to those observed in Alzheimer's disease may contribute to cognitive impairment in drug-resistant temporal lobe epilepsy. In particular, we identified several stress pathways that may represent potential novel therapeutic targets.
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Affiliation(s)
- Sarah Gourmaud
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Haochang Shou
- Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David J Irwin
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Penn Frontotemporal Degeneration Center, University of Pennsylvania, Philadelphia, PA, USA
| | - Kimberly Sansalone
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Leah M Jacobs
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Timothy H Lucas
- Department of Neurosurgery, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Eric D Marsh
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Kathryn A Davis
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Frances E Jensen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Delia M Talos
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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7
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Yoon J, Park K, Hwang DS, Rhee K. Importance of eIF2α phosphorylation as a protective mechanism against heat stress in mouse male germ cells. Mol Reprod Dev 2017; 84:265-274. [PMID: 28067447 DOI: 10.1002/mrd.22778] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 12/27/2016] [Indexed: 01/27/2023]
Abstract
Mammalian male germ cells are exceptionally labile to heat stress. A temporal arrest of translation is one immediate response to heat, which involves heat-induced phosphorylation of eukaryotic initiation factor 2α (eIF2α) to block the formation of the translational initiation complex. Here, we investigated the protective mechanisms against heat stress in mouse male germ cells. All known eIF2α kinases were expressed in lineage- and developmental stage-specific manners in the testis; noteworthy was the presence of Gcn2 (General control nonderepressible 2 kinase) in spermatocytes of all seminiferous tubules. Multiple eIF2α kinases are likely activated upon heat stress in male germ cells. ISRIB (Integrated stress response inhibitor) was then used to determine the events downstream of eIF2α phosphorylation. ISRIB significantly reduced the rate of stress granule formation in spermatocytes at early-stage (III-IV) seminiferous tubules, and induced a number of apoptotic germ cells at late-stage (XI-XII) seminiferous tubules near the onset of meiosis. Thus, stress granule formation is a downstream event of eIF2α phosphorylation that may not directly protect cells from apoptosis, at least in spermatocytes of seminiferous tubules in early stages. Mol. Reprod. Dev. 84: 265-274, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Jungbin Yoon
- Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Kyosun Park
- Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Deog Su Hwang
- Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Kunsoo Rhee
- Department of Biological Sciences, Seoul National University, Seoul, Korea
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8
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Emodin inhibits coxsackievirus B3 replication via multiple signalling cascades leading to suppression of translation. Biochem J 2015; 473:473-85. [PMID: 26621875 DOI: 10.1042/bj20150419] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 11/30/2015] [Indexed: 11/17/2022]
Abstract
CVB3 (coxsackievirus 3) is a primary causal agent of viral myocarditis. Emodin is a natural compound isolated from certain plant roots. In the present study, we found that emodin inhibited CVB3 replication in vitro and in mice, and now we report an unrecognized mechanism by which emodin inhibits CVB3 replication through suppression of viral protein translation via multiple pathways. On one hand, emodin treatment inhibited Akt/mTOR (mammalian target of rapamycin) signalling and activated 4EBP1 (eukaryotic initiation factor 4R-binding protein 1), leading to suppression of translation initiation of ribosomal protein L32 encoded by a 5'-TOP (terminal oligopyrimidine) mRNA. On the other hand, emodin treatment differentially regulated multiple signal cascades, including Akt/mTORC1/p70(S6K) (p70 S6 kinase), ERK1/2 (extracellular-signal-regulated kinase 1/2)/p90(RSK) (p90 ribosomal S6 kinase) and Ca(2+)/calmodulin, leading to activation of eEF2K (eukaryotic elongation factor 2 kinase) and subsequent inactivation of eEF2 (eukaryotic elongation factor 2), resulting in inhibition of CVB3 VP1 (viral protein 1) synthesis. These data imply that eEF2K is a major factor mediating cross-talk of different arms of signalling cascades in this signal network. This notion was verified by either overexpressing eEF2K or treating the cells with siRNAs or eEF2K inhibitor A484954. We showed further that the emodin-induced decrease in p70(S6K) phosphorylation plays a dominant positive role in activation of eEF2K and in turn in conferring the antiviral effect of emodin. This finding was further solidified by expressing constitutively active and dominant-negative Akt. Collectively, our data reveal that emodin inhibits viral replication through impairing translational machinery and suppression of viral translation elongation.
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Gangarossa G, Sakkaki S, Lory P, Valjent E. Mouse hippocampal phosphorylation footprint induced by generalized seizures: Focus on ERK, mTORC1 and Akt/GSK-3 pathways. Neuroscience 2015; 311:474-83. [PMID: 26545981 DOI: 10.1016/j.neuroscience.2015.10.051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 10/27/2015] [Indexed: 02/03/2023]
Abstract
Exacerbated hippocampal activity has been associated to critical modifications of the intracellular signaling pathways. We have investigated rapid hippocampal adaptive responses induced by maximal electroshock seizure (MES). Here, we demonstrate that abnormal and exacerbated hippocampal activity induced by MES triggers specific and temporally distinct patterns of phosphorylation of extracellular signal-related kinase (ERK), mammalian target of rapamycin complex (mTORC) and Akt/glycogen synthase kinase-3 (Akt/GSK-3) pathways in the mouse hippocampus. While the ERK pathway is transiently activated, the mTORC1 cascade follows a rapid inhibition followed by a transient activation. This rebound of mTORC1 activity leads to the selective phosphorylation of p70S6K, which is accompanied by an enhanced phosphorylation of the ribosomal subunit S6. In contrast, the Akt/GSK-3 pathway is weakly altered. Finally, MES triggers a rapid upregulation of several plasticity-associated genes as a consequence exacerbated hippocampal activity. The results reported in the present study are reminiscent of the one observed in other models of generalized seizures, thus defining a common molecular footprint induced by intense and aberrant hippocampal activities.
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Affiliation(s)
- Giuseppe Gangarossa
- CNRS, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; Inserm U1191, Montpellier F-34094, France; Université de Montpellier, Montpellier F-34094, France.
| | - Sophie Sakkaki
- CNRS, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; Inserm U1191, Montpellier F-34094, France; Université de Montpellier, Montpellier F-34094, France
| | - Philippe Lory
- CNRS, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; Inserm U1191, Montpellier F-34094, France; Université de Montpellier, Montpellier F-34094, France; LabEx 'Ion Channel Science and Therapeutics', Montpellier F-34094, France
| | - Emmanuel Valjent
- CNRS, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier F-34094, France; Inserm U1191, Montpellier F-34094, France; Université de Montpellier, Montpellier F-34094, France.
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10
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Trinh MA, Klann E. Translational control by eIF2α kinases in long-lasting synaptic plasticity and long-term memory. Neurobiol Learn Mem 2013; 105:93-9. [PMID: 23707798 DOI: 10.1016/j.nlm.2013.04.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 04/25/2013] [Accepted: 04/25/2013] [Indexed: 01/10/2023]
Abstract
Although the requirement for new protein synthesis in synaptic plasticity and memory has been well established, recent genetic, molecular, electrophysiological, and pharmacological studies have broadened our understanding of the translational control mechanisms that are involved in these processes. One of the critical translational control points mediating general and gene-specific translation depends on the phosphorylation of eukaryotic initiation factor 2 alpha (eIF2α) by four regulatory kinases. Here, we review the literature highlighting the important role for proper translational control via regulation of eIF2α phosphorylation by its kinases in long-lasting synaptic plasticity and long-term memory.
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Affiliation(s)
- Mimi A Trinh
- Pharmaceutical Research Division, CNS Drug Discovery Unit, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan
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11
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Jin CF, Li B, Lin SM, Yadav RK, Kim HR, Chae HJ. Mechanism of the Inhibitory Effects of Eucommia ulmoides Oliv. Cortex Extracts (EUCE) in the CCl 4 -Induced Acute Liver Lipid Accumulation in Rats. Int J Endocrinol 2013; 2013:751854. [PMID: 24027582 PMCID: PMC3762164 DOI: 10.1155/2013/751854] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 04/21/2013] [Accepted: 06/21/2013] [Indexed: 01/18/2023] Open
Abstract
Eucommia ulmoides Oliv. (EU) has been used for treatment of liver diseases. The protective effects of Eucommia Ulmoides Oliv. cortex extracts (EUCE) on the carbon tetrachloride- (CCl4-) induced hepatic lipid accumulation were examined in this study. Rats were orally treated with EUCE in different doses prior to an intraperitoneal injection of 1 mg/kg CCl4. Acute injection of CCl4 decreased plasma triglyceride but increased hepatic triglyceride and cholesterol as compared to control rats. On the other hand, the pretreatment with EUCE diminished these effects at a dose-dependent manner. CCl4 treatment decreased glutathione (GSH) and increased malondialdehyde (MDA) accompanied by activated P450 2E1. The pretreatment with EUCE significantly improved these deleterious effects of CCl4. CCl4 treatment increased P450 2E1 activation and ApoB accumulation. Pretreatment with EUCE reversed these effects. ER stress response was significantly increased by CCl4, which was inhibited by EUCE. One of the possible ER stress regulatory mechanisms, lysosomal activity, was examined. CCl4 reduced lysosomal enzymes that were reversed with the EUCE. The results indicate that oral pretreatment with EUCE may protect liver against CCl4-induced hepatic lipid accumulation. ER stress and its related ROS regulation are suggested as a possible mechanism in the antidyslipidemic effect of EUCE.
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Affiliation(s)
- Chang-Feng Jin
- Department of Pharmacology and Institute of Cardiovascular Research, School of Medicine, Chonbuk National University, Chonbuk, Jeonju 561-180, Republic of Korea
| | - Bo Li
- Department of Pharmacology and Institute of Cardiovascular Research, School of Medicine, Chonbuk National University, Chonbuk, Jeonju 561-180, Republic of Korea
| | - Shun-Mei Lin
- Department of Pharmacology and Institute of Cardiovascular Research, School of Medicine, Chonbuk National University, Chonbuk, Jeonju 561-180, Republic of Korea
| | - Raj-Kumar Yadav
- Department of Pharmacology and Institute of Cardiovascular Research, School of Medicine, Chonbuk National University, Chonbuk, Jeonju 561-180, Republic of Korea
| | - Hyung-Ryong Kim
- Department of Dental Pharmacology and Wonkwang Biomaterial Implant Research Institute, School of Dentistry, Wonkwang University, Chonbuk, Iksan 570-749, Republic of Korea
| | - Han-Jung Chae
- Department of Pharmacology and Institute of Cardiovascular Research, School of Medicine, Chonbuk National University, Chonbuk, Jeonju 561-180, Republic of Korea
- *Han-Jung Chae:
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Goulart-Silva F, Teixeira SDS, Luchessi AD, Dos Santos LRB, Rebelato E, Carpinelli AR, Nunes MT. Potential contribution of translational factors to triiodo-L-thyronine-induced insulin synthesis by pancreatic beta cells. Thyroid 2012; 22:637-42. [PMID: 22667453 DOI: 10.1089/thy.2011.0252] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Thyroid hormones (THs) are known to regulate protein synthesis by acting at the transcriptional level and inducing the expression of many genes. However, little is known about their role in protein expression at the post-transcriptional level, even though studies have shown enhancement of protein synthesis associated with mTOR/p70S6K activation after triiodo-L-thyronine (T3) administration. On the other hand, the effects of TH on translation initiation and polypeptidic chain elongation factors, being essential for activating protein synthesis, have been poorly explored. Therefore, considering that preliminary studies from our laboratory have demonstrated an increase in insulin content in INS-1E cells in response to T3 treatment, the aim of the present study was to investigate if proteins of translational nature might be involved in this effect. METHODS INS-1E cells were maintained in the presence or absence of T3 (10(-6) or 10(-8) M) for 12 hours. Thereafter, insulin concentration in the culture medium was determined by radioimmunoassay, and the cells were processed for Western blot detection of insulin, eukaryotic initiation factor 2 (eIF2), p-eIF2, eIF5A, EF1A, eIF4E binding protein (4E-BP), p-4E-BP, p70S6K, and p-p70S6K. RESULTS It was found that, in parallel with increased insulin generation, T3 induced p70S6K phosphorylation and the expression of the translational factors eIF2, eIF5A, and eukaryotic elongation factor 1 alpha (eEF1A). In contrast, total and phosphorylated 4E-BP, as well as total p70S6K and p-eIF2 content, remained unchanged after T3 treatment. CONCLUSIONS Considering that (i) p70S6K induces S6 phosphorylation of the 40S ribosomal subunit, an essential condition for protein synthesis; (ii) eIF2 is essential for the initiation of messenger RNA translation process; and (iii) eIF5A and eEF1A play a central role in the elongation of the polypeptidic chain during the transcripts decoding, the data presented here lead us to suppose that a part of T3-induced insulin expression in INS-1E cells depends on the protein synthesis activation at the post-transcriptional level, as these proteins of the translational machinery were shown to be regulated by T3.
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Affiliation(s)
- Francemilson Goulart-Silva
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, SP, Brazil
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Zhu PJ, Huang W, Kalikulov D, Yoo JW, Placzek AN, Stoica L, Zhou H, Bell JC, Friedlander MJ, Krnjević K, Noebels JL, Costa-Mattioli M. Suppression of PKR promotes network excitability and enhanced cognition by interferon-γ-mediated disinhibition. Cell 2012; 147:1384-96. [PMID: 22153080 DOI: 10.1016/j.cell.2011.11.029] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 09/06/2011] [Accepted: 11/02/2011] [Indexed: 01/20/2023]
Abstract
The double-stranded RNA-activated protein kinase (PKR) was originally identified as a sensor of virus infection, but its function in the brain remains unknown. Here, we report that the lack of PKR enhances learning and memory in several behavioral tasks while increasing network excitability. In addition, loss of PKR increases the late phase of long-lasting synaptic potentiation (L-LTP) in hippocampal slices. These effects are caused by an interferon-γ (IFN-γ)-mediated selective reduction in GABAergic synaptic action. Together, our results reveal that PKR finely tunes the network activity that must be maintained while storing a given episode during learning. Because PKR activity is altered in several neurological disorders, this kinase presents a promising new target for the treatment of cognitive dysfunction. As a first step in this direction, we show that a selective PKR inhibitor replicates the Pkr(-/-) phenotype in WT mice, enhancing long-term memory storage and L-LTP.
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Affiliation(s)
- Ping Jun Zhu
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
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14
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Dhote F, Carpentier P, Barbier L, Peinnequin A, Baille V, Pernot F, Testylier G, Beaup C, Foquin A, Dorandeu F. Combinations of ketamine and atropine are neuroprotective and reduce neuroinflammation after a toxic status epilepticus in mice. Toxicol Appl Pharmacol 2012; 259:195-209. [PMID: 22245128 DOI: 10.1016/j.taap.2011.12.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 12/22/2011] [Accepted: 12/26/2011] [Indexed: 01/30/2023]
Abstract
Epileptic seizures and status epilepticus (SE) induced by the poisoning with organophosphorus nerve agents (OP), like soman, are accompanied by neuroinflammation whose role in seizure-related brain damage (SRBD) is not clear. Antagonists of the NMDA glutamate ionotropic receptors are currently among the few compounds able to arrest seizures and provide neuroprotection even during refractory status epilepticus (RSE). Racemic ketamine (KET), in combination with atropine sulfate (AS), was previously shown to counteract seizures and SRBD in soman-poisoned guinea-pigs. In a mouse model of severe soman-induced SE, we assessed the potentials of KET/AS combinations as a treatment for SE/RSE-induced SRBD and neuroinflammation. When starting 30min after soman challenge, a protocol involving six injections of a sub-anesthetic dose of KET (25mg/kg) was evaluated on body weight loss, brain damage, and neuroinflammation whereas during RSE, anesthetic protocols were considered (KET 100mg/kg). After confirming that during RSE, KET injection was to be repeated despite some iatrogenic deaths, we used these proof-of-concept protocols to study the changes in mRNA and related protein contents of some inflammatory cytokines, chemokines and adhesion molecules in cortex and hippocampus 48h post-challenge. In both cases, the KET/AS combinations showed important neuroprotective effects, suppressed neutrophil granulocyte infiltration and partially suppressed glial activation. KET/AS could also reduce the increase in mRNA and related pro-inflammatory proteins provoked by the poisoning. In conclusion, the present study confirms that KET/AS treatment has a strong potential for SE/RSE management following OP poisoning. The mechanisms involved in the reduction of central neuroinflammation remain to be studied.
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Affiliation(s)
- Franck Dhote
- Département de Toxicologie et risques chimiques, Institut de Recherche Biomédicale des armées - Centre de recherches du Service de santé des armées IRBA-CRSSA, La Tronche cedex, France.
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15
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Lee GH, Kim DS, Kim HT, Lee JW, Chung CH, Ahn T, Lim JM, Kim IK, Chae HJ, Kim HR. Enhanced lysosomal activity is involved in Bax inhibitor-1-induced regulation of the endoplasmic reticulum (ER) stress response and cell death against ER stress: involvement of vacuolar H+-ATPase (V-ATPase). J Biol Chem 2011; 286:24743-53. [PMID: 21586565 DOI: 10.1074/jbc.m110.167734] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bax inhibitor-1 (BI-1) is an evolutionarily conserved protein that protects cells against endoplasmic reticulum (ER) stress while also affecting the ER stress response. In this study, we examined BI-1-induced regulation of the ER stress response as well as the control of the protein over cell death under ER stress. In BI-1-overexpressing cells (BI-1 cells), proteasome activity was similar to that of control cells; however, the lysosomal fraction of BI-1 cells showed sensitivity to degradation of BSA. In addition, areas and polygonal lengths of lysosomes were greater in BI-1 cells than in control cells, as assessed by fluorescence and electron microscopy. In BI-1 cells, lysosomal pH was lower than in control cells and lysosomal vacuolar H(+)-ATPase(V-ATPase), a proton pump, was activated, suggesting high H(+) uptake into lysosomes. Even when exposed to ER stress, BI-1 cells maintained high levels of lysosomal activities, including V-ATPase activity. Bafilomycin, a V-ATPase inhibitor, leads to the reversal of BI-1-induced regulation of ER stress response and cell death due to ER stress. In BI-1 knock-out mouse embryo fibroblasts, lysosomal activity and number per cell were relatively lower than in BI-1 wild-type cells. This study suggests that highly maintained lysosomal activity may be one of the mechanisms by which BI-1 exerts its regulatory effects on the ER stress response and cell death.
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Affiliation(s)
- Geum-Hwa Lee
- Department of Pharmacology and Cardiovascular Research Institute, Chonbuk National University, Jeonju, Chonbuk 560-180, Korea
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16
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O'Connor T, Sadleir KR, Maus E, Velliquette RA, Zhao J, Cole SL, Eimer WA, Hitt B, Bembinster LA, Lammich S, Lichtenthaler SF, Hébert SS, De Strooper B, Haass C, Bennett DA, Vassar R. Phosphorylation of the translation initiation factor eIF2alpha increases BACE1 levels and promotes amyloidogenesis. Neuron 2009; 60:988-1009. [PMID: 19109907 DOI: 10.1016/j.neuron.2008.10.047] [Citation(s) in RCA: 327] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 09/16/2008] [Accepted: 10/17/2008] [Indexed: 10/21/2022]
Abstract
beta-site APP cleaving enzyme-1 (BACE1), the rate-limiting enzyme for beta-amyloid (Abeta) production, is elevated in Alzheimer's disease (AD). Here, we show that energy deprivation induces phosphorylation of the translation initiation factor eIF2alpha (eIF2alpha-P), which increases the translation of BACE1. Salubrinal, an inhibitor of eIF2alpha-P phosphatase PP1c, directly increases BACE1 and elevates Abeta production in primary neurons. Preventing eIF2alpha phosphorylation by transfection with constitutively active PP1c regulatory subunit, dominant-negative eIF2alpha kinase PERK, or PERK inhibitor P58(IPK) blocks the energy-deprivation-induced BACE1 increase. Furthermore, chronic treatment of aged Tg2576 mice with energy inhibitors increases levels of eIF2alpha-P, BACE1, Abeta, and amyloid plaques. Importantly, eIF2alpha-P and BACE1 are elevated in aggressive plaque-forming 5XFAD transgenic mice, and BACE1, eIF2alpha-P, and amyloid load are correlated in humans with AD. These results strongly suggest that eIF2alpha phosphorylation increases BACE1 levels and causes Abeta overproduction, which could be an early, initiating molecular mechanism in sporadic AD.
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Affiliation(s)
- Tracy O'Connor
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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17
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Richter JD, Klann E. Making synaptic plasticity and memory last: mechanisms of translational regulation. Genes Dev 2009; 23:1-11. [PMID: 19136621 DOI: 10.1101/gad.1735809] [Citation(s) in RCA: 272] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Synaptic transmission in neurons is a measure of communication at synapses, the points of contact between axons and dendrites. The magnitude of synaptic transmission is a reflection of the strength of these synaptic connections, which in turn can be altered by the frequency with which the synapses are stimulated, the arrival of stimuli from other neurons in the appropriate temporal window, and by neurotrophic factors and neuromodulators. The ability of synapses to undergo lasting biochemical and morphological changes in response to these types of stimuli and neuromodulators is known as synaptic plasticity, which likely forms the cellular basis for learning and memory, although the relationship between any one form synaptic plasticity and a particular type of memory is unclear. RNA metabolism, particularly translational control at or near the synapse, is one process that controls long-lasting synaptic plasticity and, by extension, several types of memory formation and consolidation. Here, we review recent studies that reflect the importance and challenges of investigating the role of mRNA translation in synaptic plasticity and memory formation.
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Affiliation(s)
- Joel D Richter
- Program in Molecular Medicine University of Massachusetts Medical School Worcester, Massachusetts 01605, USA.
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18
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Alves VS, Motta FL, Roffé M, Delamano A, Pesquero JB, Castilho BA. GCN2 activation and eIF2α phosphorylation in the maturation of mouse oocytes. Biochem Biophys Res Commun 2009; 378:41-4. [DOI: 10.1016/j.bbrc.2008.10.161] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Accepted: 10/28/2008] [Indexed: 12/21/2022]
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19
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Yuan CL, Sharma N, Gilge DA, Stanley WC, Li Y, Hatzoglou M, Previs SF. Preserved protein synthesis in the heart in response to acute fasting and chronic food restriction despite reductions in liver and skeletal muscle. Am J Physiol Endocrinol Metab 2008; 295:E216-22. [PMID: 18445754 PMCID: PMC2493593 DOI: 10.1152/ajpendo.00545.2007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Whole body protein synthesis is reduced during the fed-to-fasted transition and in cases of chronic dietary restriction; however, less is known about tissue-specific alterations. We have assessed the extent to which protein synthesis in cardiac muscle responds to dietary perturbations compared with liver and skeletal muscle by applying a novel (2)H(2)O tracer method to quantify tissue-specific responses of protein synthesis in vivo. We hypothesized that protein synthesis in cardiac muscle would be unaffected by acute fasting or food restriction, whereas protein synthesis in the liver and gastrocnemius muscle would be reduced when there is a protein-energy deficit. We found that, although protein synthesis in liver and gastrocnemius muscle was significantly reduced by acute fasting, there were no changes in protein synthesis in the left ventricle of the heart for either the total protein pool or in isolated mitochondrial or cytosolic compartments. Likewise, a chronic reduction in calorie intake, induced by food restriction, did not affect protein synthesis in the heart, whereas protein synthesis in skeletal muscle and liver was decreased. The later observations are supported by changes in the phosphorylation state of two critical mediators of protein synthesis (4E-BP1 and eIF2alpha) in the respective tissues. We conclude that cardiac protein synthesis is maintained in cases of nutritional perturbations, in strong contrast to liver and gastrocnemius muscle, where protein synthesis is decreased by acute fasting or chronic food restriction.
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Affiliation(s)
- Celvie L Yuan
- Department of Nutrition, Case Western Reserve University School of Medicine, 10900 Euclid Ave., Cleveland, OH 44106, USA
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20
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Murphy N, Bonner HP, Ward MW, Murphy BM, Prehn JHM, Henshall DC. Depletion of 14-3-3 zeta elicits endoplasmic reticulum stress and cell death, and increases vulnerability to kainate-induced injury in mouse hippocampal cultures. J Neurochem 2008; 106:978-88. [PMID: 18466333 DOI: 10.1111/j.1471-4159.2008.05447.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
14-3-3 proteins are ubiquitous signalling molecules that regulate development and survival pathways in brain. Altered expression and cellular localization of 14-3-3 proteins has been implicated in neurodegenerative diseases and in neuronal death after acute neurological insults, including seizures. Presently, we examined expression and function of 14-3-3 isoforms in vitro using mouse organotypic hippocampal cultures. Treatment of cultures with the endoplasmic reticulum (ER) stressor tunicamycin caused an increase in levels of 14-3-3 zeta within the ER-containing microsomal fraction, along with up-regulation of Lys-Asp-Glu-Leu-containing proteins and calnexin, and the selective death of dentate granule cells. Depletion of 14-3-3 zeta levels using small interfering RNA induced both ER stress proteins and death of granule cells. Treatment of hippocampal cultures with the excitotoxin kainic acid increased levels of Lys-Asp-Glu-Leu-containing proteins and microsomal 14-3-3 zeta levels and caused cell death within the CA1, CA3 and dentate gyrus of the hippocampus. Kainic acid-induced damage was significantly increased in each hippocampal subfield of cultures treated with small interfering RNA targeting 14-3-3 zeta. The present data indicate a role for 14-3-3 zeta in survival responses following ER stress and possibly protection against seizure injury to the hippocampus.
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Affiliation(s)
- Niamh Murphy
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland, UK
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21
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Henshall DC, Murphy BM. Modulators of neuronal cell death in epilepsy. Curr Opin Pharmacol 2007; 8:75-81. [PMID: 17827063 DOI: 10.1016/j.coph.2007.07.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Accepted: 07/30/2007] [Indexed: 10/22/2022]
Abstract
Experimental and human data have shown that certain seizures cause damage to brain. Such neuronal loss may result in cognitive impairments and perhaps contribute to the development or phenotype of emergent epilepsy. Recent work using genetically modified mice, Tat protein transduction, and viral vectors has shown functional effects of manipulating Bcl-2 and Bcl-w, heat shock proteins, caspases, and their regulators and endonucleases on neuronal death in models of status epilepticus. Ancillary effects on seizure induction and excitability thresholds have emerged for several genes suggesting additional properties of therapeutic potential. Differing hippocampal expression of certain Bcl-2 family genes, elevated endoplasmic reticulum stress chaperones, and death receptor pathway modulation in epilepsy patients support clinical relevance of this focus. These findings may yield potentially valuable adjunctive neuroprotective or anti-epileptogenic strategies.
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Affiliation(s)
- David C Henshall
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
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22
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Joshi M, Jeoung N, Obayashi M, Hattab E, Brocken E, Liechty E, Kubek M, Vattem K, Wek R, Harris R. Impaired growth and neurological abnormalities in branched-chain alpha-keto acid dehydrogenase kinase-deficient mice. Biochem J 2006; 400:153-62. [PMID: 16875466 PMCID: PMC1635446 DOI: 10.1042/bj20060869] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The BCKDH (branched-chain alpha-keto acid dehydrogenase complex) catalyses the rate-limiting step in the oxidation of BCAAs (branched-chain amino acids). Activity of the complex is regulated by a specific kinase, BDK (BCKDH kinase), which causes inactivation, and a phosphatase, BDP (BCKDH phosphatase), which causes activation. In the present study, the effect of the disruption of the BDK gene on growth and development of mice was investigated. BCKDH activity was much greater in most tissues of BDK-/- mice. This occurred in part because the E1 component of the complex cannot be phosphorylated due to the absence of BDK and also because greater than normal amounts of the E1 component were present in tissues of BDK-/- mice. Lack of control of BCKDH activity resulted in markedly lower blood and tissue levels of the BCAAs in BDK-/- mice. At 12 weeks of age, BDK-/- mice were 15% smaller than wild-type mice and their fur lacked normal lustre. Brain, muscle and adipose tissue weights were reduced, whereas weights of the liver and kidney were greater. Neurological abnormalities were apparent by hind limb flexion throughout life and epileptic seizures after 6-7 months of age. Inhibition of protein synthesis in the brain due to hyperphosphorylation of eIF2alpha (eukaryotic translation initiation factor 2alpha) might contribute to the neurological abnormalities seen in BDK-/- mice. BDK-/- mice show significant improvement in growth and appearance when fed a high protein diet, suggesting that higher amounts of dietary BCAA can partially compensate for increased oxidation in BDK-/- mice. Disruption of the BDK gene establishes that regulation of BCKDH by phosphorylation is critically important for the regulation of oxidative disposal of BCAAs. The phenotype of the BDK-/- mice demonstrates the importance of tight regulation of oxidative disposal of BCAAs for normal growth and neurological function.
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Affiliation(s)
- Mandar A. Joshi
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, U.S.A
| | - Nam Ho Jeoung
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, U.S.A
| | - Mariko Obayashi
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, U.S.A
| | - Eyas M. Hattab
- †Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, U.S.A
| | - Eric G. Brocken
- †Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, U.S.A
| | - Edward A. Liechty
- ‡Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN 46202, U.S.A
| | - Michael J. Kubek
- §Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, U.S.A
| | - Krishna M. Vattem
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, U.S.A
| | - Ronald C. Wek
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, U.S.A
| | - Robert A. Harris
- *Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, U.S.A
- To whom correspondence should be addressed (email )
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23
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de Wit MCY, de Coo IFM, Julier C, Delépine M, Lequin MH, van de Laar I, Sibbles BJ, Bruining GJ, Mancini GMS. Microcephaly and simplified gyral pattern of the brain associated with early onset insulin-dependent diabetes mellitus. Neurogenetics 2006; 7:259-63. [PMID: 16972080 DOI: 10.1007/s10048-006-0061-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2006] [Accepted: 08/10/2006] [Indexed: 11/25/2022]
Abstract
Two families are presented with a child suffering from microcephaly with a simplified gyral pattern of the brain (SGP) and early onset insulin dependent diabetes mellitus (IDDM). The first patient was diagnosed postmortally with Wolcott-Rallison syndrome, after her younger brother developed IDDM, and a homozygous mutation in the eukaryotic translation initiation factor 2-alpha kinase 3 was found. The younger brother did not undergo magnetic resonance imaging (MRI). The patient from the second family has no EIF2AK3 mutation. SGP is considered to arise from decreased neuronal proliferation or increased apoptosis at an early stage of embryonal development, but insight into the pathways involved is minimal. EIF2AK3 is involved in translation initiation. It has been proposed that loss of function mutations reduce the ability of the cell to respond to endoplasmic reticulum stress, resulting in apoptosis of pancreatic Langerhans cells. Our findings suggest that in some cases, early onset IDDM and SGP can arise from common mechanisms leading to increased apoptosis.
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Affiliation(s)
- M C Y de Wit
- Department of Pediatric Neurology, Erasmus Medical Center Sophia Children's Hospital, Rotterdam, The Netherlands
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Chang RCC, Yu MS, Lai CSW. Significance of Molecular Signaling for Protein Translation Control in Neurodegenerative Diseases. Neurosignals 2006; 15:249-58. [PMID: 17496426 DOI: 10.1159/000102599] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Accepted: 03/21/2007] [Indexed: 11/19/2022] Open
Abstract
It has long been known that protein synthesis is inhibited in neurological disorders. Protein synthesis includes protein transcription and translation. While many studies about protein transcription have been done in the last decade, we are just starting to understand more about the impact of protein translation. Protein translation control can be accomplished at the initiation or elongation steps. In this review, we will focus on translation control at initiation. Neurons have long neurites in which proteins have to be transported from the cell body to the end of the neurite. Since supply of proteins cannot meet the need of neuronal activity at the spine, protein locally translated at the spine will be a good solution to replace the turnover of proteins. Therefore, local protein translation is an important mechanism to maintain normal neuronal functions. In this notion, we have to separate the concept of global and local protein translation control. Both global and local protein translation control modulate normal neuronal functions from development to cognitive functions. Increasing lines of evidence show that they also play significant roles in neurodegenerative diseases, e.g. neuronal apoptosis, synaptic degeneration and autophagy. We summarize all the evidence in this review and focus on the control at initiation. The new live-cell imaging technology together with photoconvertible fluorescent probes allows us to investigate newly translated proteins in situ. Protein translation control is another line to modulate neuronal function in neuron-neuron communication as well as in response to stress in neurodegenerative diseases.
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Affiliation(s)
- Raymond Chuen-Chung Chang
- Laboratory of Neurodegenerative Diseases, Department of Anatomy, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China.
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