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Yang Q, Zhou X, Ma T. Isoform-specific effects of neuronal inhibition of AMPK catalytic subunit on LTD impairments in a mouse model of Alzheimer's disease. Neurobiol Aging 2024; 140:116-121. [PMID: 38763076 PMCID: PMC11179164 DOI: 10.1016/j.neurobiolaging.2024.05.009] [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: 01/30/2024] [Revised: 04/16/2024] [Accepted: 05/10/2024] [Indexed: 05/21/2024]
Abstract
Synaptic dysfunction is highly correlated with cognitive impairments in Alzheimer's disease (AD), the most common dementia syndrome in the elderly. Long-term potentiation (LTP) and long-term depression (LTD) are two primary forms of synaptic plasticity with opposite direction of synaptic efficiency change. Both LTD and LTD are considered to mediate the cellular process of learning and memory. Substantial studies demonstrate AD-associated deficiency of both LTP and LTD. Meanwhile, the molecular signaling mechanisms underlying impairment of synaptic plasticity, particularly LTD, are poorly understood. By taking advantage of the novel transgenic mouse models recently developed in our lab, here we aimed to investigate the roles of AMP-activated protein kinase (AMPK), a central molecular senor that plays a critical role in maintaining cellular energy homeostasis, in regulation of LTD phenotypes in AD. We found that brain-specific suppression of the AMPKα1 isoform (but not AMPKα2 isoform) was able to alleviate mGluR-LTD deficits in APP/PS1 AD mouse model. Moreover, suppression of either AMPKα isoform failed to alleviate AD-related NMDAR-dependent LTD deficits. Taken together with our recent studies on roles of AMPK signaling in AD pathophysiology, the data indicate isoform-specific roles of AMPK in mediating AD-associated synaptic and cognitive impairments.
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Affiliation(s)
- Qian Yang
- Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Xueyan Zhou
- Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Tao Ma
- Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA; Department of Translational Neuroscience, Wake Forest University School of Medicine, USA.
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2
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Albert-Gasco H, Smith HL, Alvarez-Castelao B, Swinden D, Halliday M, Janaki-Raman S, Butcher AJ, Mallucci GR. Trazodone rescues dysregulated synaptic and mitochondrial nascent proteomes in prion neurodegeneration. Brain 2024; 147:649-664. [PMID: 37703312 PMCID: PMC10834243 DOI: 10.1093/brain/awad313] [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: 06/02/2023] [Revised: 09/01/2023] [Accepted: 09/01/2023] [Indexed: 09/15/2023] Open
Abstract
The unfolded protein response (UPR) is rapidly gaining momentum as a therapeutic target for protein misfolding neurodegenerative diseases, in which its overactivation results in sustained translational repression leading to synapse loss and neurodegeneration. In mouse models of these disorders, from Alzheimer's to prion disease, modulation of the pathway-including by the licensed drug, trazodone-restores global protein synthesis rates with profound neuroprotective effects. However, the precise nature of the translational impairment, in particular the specific proteins affected in disease, and their response to therapeutic UPR modulation are poorly understood. We used non-canonical amino acid tagging (NCAT) to measure de novo protein synthesis in the brains of prion-diseased mice with and without trazodone treatment, in both whole hippocampus and cell-specifically. During disease the predominant nascent proteome changes occur in synaptic, cytoskeletal and mitochondrial proteins in both hippocampal neurons and astrocytes. Remarkably, trazodone treatment for just 2 weeks largely restored the whole disease nascent proteome in the hippocampus to that of healthy, uninfected mice, predominantly with recovery of proteins involved in synaptic and mitochondrial function. In parallel, trazodone treatment restored the disease-associated decline in synapses and mitochondria and their function to wild-type levels. In conclusion, this study increases our understanding of how translational repression contributes to neurodegeneration through synaptic and mitochondrial toxicity via depletion of key proteins essential for their function. Further, it provides new insights into the neuroprotective mechanisms of trazodone through reversal of this toxicity, relevant for the treatment of neurodegenerative diseases via translational modulation.
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Affiliation(s)
- Hector Albert-Gasco
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
| | - Heather L Smith
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
| | - Beatriz Alvarez-Castelao
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, 28040 Madrid, Spain
- The San Carlos Hospital Health Research Institute, IdISSC, 28040 Madrid, Spain
| | - Dean Swinden
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
| | - Mark Halliday
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
| | | | - Adrian J Butcher
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
| | - Giovanna R Mallucci
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0AH, UK
- Cambridge Institute of Science, Altos Labs, Great Abington CB21 6GP, UK
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3
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Piserchio A, Dalby KN, Ghose R. Revealing eEF-2 kinase: recent structural insights into function. Trends Biochem Sci 2024; 49:169-182. [PMID: 38103971 PMCID: PMC10950556 DOI: 10.1016/j.tibs.2023.11.004] [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: 08/15/2023] [Revised: 11/14/2023] [Accepted: 11/17/2023] [Indexed: 12/19/2023]
Abstract
The α-kinase eukaryotic elongation factor 2 kinase (eEF-2K) regulates translational elongation by phosphorylating its ribosome-associated substrate, the GTPase eEF-2. eEF-2K is activated by calmodulin (CaM) through a distinctive mechanism unlike that in other CaM-dependent kinases (CAMK). We describe recent structural insights into this unique activation process and examine the effects of specific regulatory signals on this mechanism. We also highlight key unanswered questions to guide future structure-function studies. These include structural mechanisms which enable eEF-2K to interact with upstream/downstream partners and facilitate its integration of diverse inputs, including Ca2+ transients, phosphorylation mediated by energy/nutrient-sensing pathways, pH changes, and metabolites. Answering these questions is key to establishing how eEF-2K harmonizes translation with cellular requirements within the boundaries of its molecular landscape.
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Affiliation(s)
- Andrea Piserchio
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA
| | - Kevin N Dalby
- Division of Chemical Biology and Medicinal Chemistry, The University of Texas, Austin, TX 78712, USA.
| | - Ranajeet Ghose
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA; The Graduate Center of The City University of New York (CUNY), New York, NY 10016, USA.
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Johnson JL, Steele JH, Lin R, Stepanov VG, Gavriliuc MN, Wang Y. Multi-Channel smFRET study reveals a Compact conformation of EF-G on the Ribosome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.27.577133. [PMID: 38328191 PMCID: PMC10849647 DOI: 10.1101/2024.01.27.577133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
While elongation factor G (EF-G) is crucial for ribosome translocation, the role of its GTP hydrolysis remains ambiguous. EF-G's indispensability is further exemplified by the phosphorylation of human eukaryotic elongation factor 2 (eEF2) at Thr56, which inhibits protein synthesis globally, but its exact mechanism is not clear. In this study, we developed a multi-channel single-molecule FRET (smFRET) microscopy methodology to examine the conformational changes of E. coli EF-G induced by mutations that closely aligned with eEF2's Thr56 residue. We utilized Alexa 488/594 double-labeled EF-G to catalyze the translocation of fMet-Phe-tRNAPhe-Cy3 inside Cy5-L27 labeled ribosomes, allowing us to probe both processes within the same complex. Our findings indicate that in the presence of either GTP or GDPCP, wild-type EF-G undergoes a conformational extension upon binding to the ribosome to promote normal translocation. On the other hand, T48E and T48V mutations did not affect GTP/GDP binding or GTP hydrolysis, but impeded Poly(Phe) synthesis and caused EF-G to adopt a unique compact conformation, which wasn't observed when the mutants interact solely with the sarcin/ricin loop. This study provides new insights into EF-G's adaptability and sheds light on the modification mechanism of human eEF2.
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Affiliation(s)
- Jordan L Johnson
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Jacob H Steele
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Ran Lin
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Victor G Stepanov
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Miriam N Gavriliuc
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Yuhong Wang
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
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Yao X, Xu X, Hu K, Yang Z, Deng S. BANF1 promotes glutamate-induced apoptosis of HT-22 hippocampal neurons. Mol Biol Rep 2023; 50:9441-9452. [PMID: 37838622 DOI: 10.1007/s11033-023-08889-1] [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: 04/13/2023] [Accepted: 10/04/2023] [Indexed: 10/16/2023]
Abstract
BACKGROUND Glutamate exposure was fatal to HT-22 neuronal cells that derived from mouse hippocampus. This is often used as a model for hippocampus neurodegeneration in vitro. The targets relevant to glutamate-induced neuronal toxicity is not fully understood. In this study, we aimed to identify crucial factors associated with glutamate-induced cytotoxicity in HT-22 cells. METHODS HT-22 cells were treated with 7.5 mM glutamate for 24 h and isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis conducted to identify the differentially expressed proteins. Differential proteins were subjected to Gene Ontology analyses. Upregulation of barrier to autointegration factor (BANF1/BANF1) protein was confirmed by RT-qPCR and western blotting. Cell viability was measured by CKK-8 and MTT assays. Cell apoptosis rates and intracellular reactive oxygen species (ROS) levels were detected using flow cytometry. RESULTS A total of 5811 proteins were quantified by iTRAQ, 50 of which were recognized as significantly differential proteins (fold change ≥ 1.5 and P ≤ 0.05); 26 proteins were up-regulated and 24 were down-regulated after exposure to glutamate. GO enrichment analysis showed that the apoptotic signaling pathway was involved in cell death induced by glutamate. BANF1 expression level was markedly increased in HT-22 cells after glutamate treatment. Further, knockdown of BANF1 alleviated glutamate-mediated cell death with lower ROS levels. CONCLUSIONS In conclusion, we successfully filtered out differential proteins relevant to glutamate-mediated cytotoxicity. BANF1 upregulation promoted glutamate-induced apoptosis of HT-22 cells by enhancing ROS generation.
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Affiliation(s)
- Xinyu Yao
- State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Xiaoyi Xu
- Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, Guangdong, China
| | - Kunhua Hu
- Proteomics Research Center, Sun Yat-Sen Medical College of Sun Yat-Sen University, Guangzhou, 510080, China
| | - Zhaoshou Yang
- The First Affiliated Hospital/School of Clinical Medicine of Guangdong Pharmaceutical University, Guangdong Pharmaceutical University, Guangzhou, 510080, China.
| | - Shaodong Deng
- The First Dongguan Affiliated Hospital of Guangdong Medical University, Dongguan, 523710, Guangdong, China.
- Scientific Research Platform, The Second Clinical Medical College, Guangdong Medical University, Dongguan, 523808, China.
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Hu K, Wang C, Xu Y, Li F, Han X, Song C, Liang M. Interaction of lncRNA Gm2044 and EEF2 promotes estradiol synthesis in ovarian follicular granulosa cells. J Ovarian Res 2023; 16:171. [PMID: 37612724 PMCID: PMC10464411 DOI: 10.1186/s13048-023-01232-z] [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: 08/29/2022] [Accepted: 07/07/2023] [Indexed: 08/25/2023] Open
Abstract
The functions and molecular mechanisms of long noncoding RNA (lncRNA) in reproduction have been widely studied at present. However, lncRNA regulating hormone synthesis in ovarian follicular granulosa cells has not been sufficiently studied. Our previous research demonstrated that lncRNA Gm2044 could promote estradiol synthesis in follicular granulosa cells. In this study, we identified 21 binding proteins of lncRNA Gm2044 in ovarian follicles using comprehensive identification of RNA-binding proteins by mass spectrometry (ChIRP-MS). RNA immunoprecipitation (RNA IP) and reverse transcription PCR (RT-PCR) confirmed that lncRNA Gm2044 can interact with eukaryotic translation elongation factor 2 (EEF2) protein. Furthermore, we constructed lncRNA Gm2044 knockout mice using the CRISPR/Cas9 method. Although the follicular development and fertility of female lncRNA Gm2044 knockout mice were not affected, the serum estradiol concentration in female lncRNA Gm2044 knockout mice significantly decreased. Western blotting and ELISA revealed that lncRNA Gm2044 may promote the binding of EEF2 to Nr5a1 mRNA and then enhance the Nr5a1 mRNA translation, and the upregulated NR5A1 protein can strengthen estradiol synthesis. To determine the potential signaling pathway of lncRNA Gm2044 regulating estradiol synthesis, transcriptome sequencing was performed for ovaries of adult lncRNA Gm2044 knockout mice, which identified 565 significant up-regulated genes and 303 significant down-regulated genes, which were then analyzed with Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) and validated by molecular experiments. Understanding how lncRNA Gm2044/EEF2 protein regulates estradiol synthesis will help treat estrogen-related reproductive diseases.
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Affiliation(s)
- Ke Hu
- School of Life Science, Bengbu Medical College, Bengbu, China
| | - Chen Wang
- School of Life Science, Bengbu Medical College, Bengbu, China
| | - Yifan Xu
- School of Life Science, Bengbu Medical College, Bengbu, China
| | - Fan Li
- School of Laboratory Medicine, Bengbu Medical College, Bengbu, China
| | - Xuefeng Han
- School of Life Science, Bengbu Medical College, Bengbu, China
| | - Chuanwang Song
- School of Laboratory Medicine, Bengbu Medical College, Bengbu, China.
| | - Meng Liang
- School of Life Science, Bengbu Medical College, Bengbu, China.
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Piserchio A, Isiorho EA, Dalby KN, Ghose R. Structure of the complex between calmodulin and a functional construct of eukaryotic elongation factor 2 kinase bound to an ATP-competitive inhibitor. J Biol Chem 2023:104813. [PMID: 37172726 DOI: 10.1016/j.jbc.2023.104813] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/06/2023] [Accepted: 05/08/2023] [Indexed: 05/15/2023] Open
Abstract
The calmodulin-activated α-kinase, eukaryotic elongation factor 2 kinase (eEF-2K) serves as a master regulator of translational elongation by specifically phosphorylating and reducing the ribosome-affinity of the guanosine triphosphatase, eukaryotic elongation factor 2 (eEF-2). Given its critical role in a fundamental cellular process, dysregulation of eEF-2K has been implicated in several human diseases, including those of the cardiovascular system, chronic neuropathies, and many cancers, making it a critical pharmacological target. In the absence of high-resolution structural information, high-throughput screening efforts have yielded small-molecule candidates that show promise as eEF-2K antagonists. Principal among these is the ATP-competitive pyrimido-pyrimidinedione inhibitor, A-484954, which shows high specificity towards eEF-2K relative to a panel of "typical" protein kinases. A-484954 has been shown to have some degree of efficacy in animal models of several disease states. It has also been widely deployed as a reagent in eEF-2K-specific biochemical and cell-biological studies. However, given the absence of structural information, the precise mechanism of the A-484954-mediated inhibition of eEF-2K has remained obscure. Leveraging our identification of the calmodulin-activatable catalytic core of eEF-2K and our recent determination of its long-elusive structure, here we present the structural basis for its specific inhibition by A-484954. This structure, which represents the first for an inhibitor-bound catalytic domain of a member of the α-kinase family, enables rationalization of the existing structure-activity relationship data for A-484954 variants and lays the groundwork for further optimization of this scaffold to attain enhanced specificity/potency against eEF-2K.
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Affiliation(s)
- Andrea Piserchio
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031
| | - Eta A Isiorho
- Macromolecular Crystallization Facility, CUNY ASRC, New York, NY 10031
| | - Kevin N Dalby
- Division of Chemical Biology and Medicinal Chemistry, the University of Texas, Austin, TX 78712; Interdisciplinary Life Sciences Graduate Program, the University of Texas, Austin, TX 78712.
| | - Ranajeet Ghose
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031; PhD Program in Biochemistry, The Graduate Center of CUNY, New York, NY 10016; PhD Program in Chemistry, The Graduate Center of CUNY, New York, NY 10016; PhD Program in Physics, The Graduate Center of CUNY, New York, NY 10016.
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Kasica NP, Zhou X, Jester HM, Holland CE, Ryazanov AG, Forshaw TE, Furdui CM, Ma T. Homozygous knockout of eEF2K alleviates cognitive deficits in APP/PS1 Alzheimer’s disease model mice independent of brain amyloid β pathology. Front Aging Neurosci 2022; 14:959326. [PMID: 36158543 PMCID: PMC9500344 DOI: 10.3389/fnagi.2022.959326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/23/2022] [Indexed: 11/25/2022] Open
Abstract
Maintenance of memory and synaptic plasticity depends on de novo protein synthesis, and accumulating evidence implicates a role of dysregulated mRNA translation in cognitive impairments associated with Alzheimer’s disease (AD). Accumulating evidence demonstrates hyper-phosphorylation of translation factor eukaryotic elongation factor 2 (eEF2) in the hippocampi of human AD patients as well as transgenic AD model mice. Phosphorylation of eEF2 (at the Thr 56 site) by its only known kinase, eEF2K, leads to inhibition of general protein synthesis. A recent study suggests that amyloid β (Aβ)-induced neurotoxicity could be associated with an interaction between eEF2 phosphorylation and the transcription factor nuclear erythroid 2-related factor (NRF2)-mediated antioxidant response. In this brief communication, we report that global homozygous knockout of the eEF2K gene alleviates deficits of long-term recognition and spatial learning in a mouse model of AD (APP/PS1). Moreover, eEF2K knockout does not alter brain Aβ pathology in APP/PS1 mice. The hippocampal NRF2 antioxidant response in the APP/PS1 mice, measured by expression levels of nicotinamide adenine dinucleotide plus hydrogen (NADPH) quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1), is ameliorated by suppression of eEF2K signaling. Together, the findings may contribute to our understanding of the molecular mechanisms underlying AD pathogenesis, indicating that suppression of eEF2K activity could be a beneficial therapeutic option for this devastating neurodegenerative disease.
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Affiliation(s)
- Nicole P. Kasica
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Xueyan Zhou
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Hannah M. Jester
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Caroline E. Holland
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Alexey G. Ryazanov
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, United States
| | - Tom E. Forshaw
- Section on Molecular Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Cristina M. Furdui
- Section on Molecular Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
| | - Tao Ma
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, United States
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, United States
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC, United States
- *Correspondence: Tao Ma,
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