1
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Jiang Y, Jin X, Chi Z, Bai Y, Manthiram K, Mudd P, Zhu K, Wang L, Schwartzberg PL, Han Y, Gao X, Lu L, Xu Q. Protein phosphatase 2A propels follicular T helper cell development in lupus. J Autoimmun 2023; 136:103028. [PMID: 37001432 PMCID: PMC10327577 DOI: 10.1016/j.jaut.2023.103028] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 01/09/2023] [Accepted: 03/09/2023] [Indexed: 03/31/2023]
Abstract
Follicular helper T (Tfh) cells are important for generating humoral immune responses by helping B cells form germinal centers (GCs) and the production of high-affinity antibodies. However, aberrant Tfh cell expansion also contributes to the generation of self-reactive autoantibodies and promotes autoantibody-mediated autoimmune diseases such as systemic lupus erythematosus (SLE). Protein phosphatase 2A catalytic subunit alpha isoform (PP2A Cα) expression levels are elevated in peripheral T cells of SLE patients and positively correlate with autoantibody titers and disease activity. Here, we demonstrate a critical role of PP2A in Tfh differentiation by using T cell restricted PP2A Cα deficient mice. We observed impaired Tfh differentiation and GC response in two different classical Tfh induction models. Mechanistic studies revealed that downregulation of protein translation of the Tfh lineage transcription factor BCL6 in PP2A deficient T cells. Importantly, we found that PP2A deficiency by either gene knockout or chemical inhibition alleviated lupus severity in mice. Lastly, we confirmed a positive correlation between PP2A Cα and BCL6 protein levels in human CD4+ T cells from patients with SLE. In summary, our study revealed a critical role of PP2A in regulating Tfh cells and suggests it is a potential therapeutic target for lupus.
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Affiliation(s)
- Yu Jiang
- Institute of Immunology, and Department of Rheumatology in Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, PR China
| | - Xuexiao Jin
- Institute of Immunology, and Department of Rheumatology in Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, PR China
| | - Zhexu Chi
- International Institutes of Medicine, The Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu, Zhejiang, 322000, China; Department of Immunology, Zhejiang University School of Medicine, Hangzhou, 310058, PR China
| | - Yadan Bai
- Institute of Immunology, and Department of Rheumatology in Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, PR China
| | - Kalpana Manthiram
- Cell Signaling and Immunity Section, Laboratory of Immune System Biology (LISB), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Pamela Mudd
- Division of Pediatric Otolaryngology, Children's National Hospital, Washington, DC, USA; Division of Otolaryngology, Department of Surgery, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Kaixiang Zhu
- Institute of Immunology, and Department of Rheumatology in Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, PR China; Shanghai Immune Therapy Institute, Shanghai Jiao Tong University School of Medicine Affiliated Renji Hospital, Shanghai, 200127, China
| | - Lie Wang
- Department of Immunology, Zhejiang University School of Medicine, Hangzhou, 310058, PR China
| | - Pamela L Schwartzberg
- Cell Signaling and Immunity Section, Laboratory of Immune System Biology (LISB), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Yongmei Han
- Department of Rheumatology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, PR China
| | - Xiang Gao
- Key Laboratory of Model Animals for Disease Study of the Ministry of Education, Model Animal Research Center, Nanjing University, Nanjing, 210061, PR China
| | - Linrong Lu
- Institute of Immunology, and Department of Rheumatology in Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, PR China; Shanghai Immune Therapy Institute, Shanghai Jiao Tong University School of Medicine Affiliated Renji Hospital, Shanghai, 200127, China.
| | - Qin Xu
- Institute of Immunology, and Department of Rheumatology in Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, PR China; Cell Signaling and Immunity Section, Laboratory of Immune System Biology (LISB), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA.
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2
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Yang T, Zhang Y, Chen L, Thomas ER, Yu W, Cheng B, Li X. The potential roles of ATF family in the treatment of Alzheimer's disease. Biomed Pharmacother 2023; 161:114544. [PMID: 36934558 DOI: 10.1016/j.biopha.2023.114544] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/07/2023] [Accepted: 03/14/2023] [Indexed: 03/20/2023] Open
Abstract
Activating transcription factors, ATFs, is a family of transcription factors that activate gene expression and transcription by recognizing and combining the cAMP response element binding proteins (CREB). It is present in various viruses as a cellular gene promoter. ATFs is involved in regulating the mammalian gene expression that is associated with various cell physiological processes. Therefore, ATFs play an important role in maintaining the intracellular homeostasis. ATF2 and ATF3 is mostly involved in mediating stress responses. ATF4 regulates the oxidative metabolism, which is associated with the survival of cells. ATF5 is presumed to regulate apoptosis, and ATF6 is involved in the regulation of endoplasmic reticulum stress (ERS). ATFs is actively studied in oncology. At present, there has been an increasing amount of research on ATFs for the treatment of neurological diseases. Here, we have focused on the different types of ATFs and their association with Alzheimer's disease (AD). The level of expression of different ATFs have a significant difference in AD patients when compared to healthy control. Recent studies have suggested that ATFs are implicated in the pathogenesis of AD, such as neuronal repair, maintenance of synaptic activity, maintenance of cell survival, inhibition of apoptosis, and regulation of stress responses. In this review, the potential role of ATFs for the treatment of AD has been highlighted. In addition, we have systematically reviewed the progress of research on ATFs in AD. This review will provide a basic and innovative understanding on the pathogenesis and treatment of AD.
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Affiliation(s)
- Ting Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Southwest Medical University, Luzhou 646000, China
| | - Yuhong Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Southwest Medical University, Luzhou 646000, China
| | - Lixuan Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Southwest Medical University, Luzhou 646000, China
| | | | - Wenjing Yu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Southwest Medical University, Luzhou 646000, China
| | - Bo Cheng
- Department of Urology, The Affiliated Hospital of Southwest Medical University, Luzhou 646000, China; Sichuan Clinical Research Center for Nephropathy, Luzhou 646000, China.
| | - Xiang Li
- Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Southwest Medical University, Luzhou 646000, China.
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3
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Pan B, Lu X, Han X, Huan J, Gao D, Cui S, Ju X, Zhang Y, Xu S, Song J, Wang L, Zhang H, Niu Q. Mechanism by Which Aluminum Regulates the Abnormal Phosphorylation of the Tau Protein in Different Cell Lines. ACS OMEGA 2021; 6:31782-31796. [PMID: 34870001 PMCID: PMC8637959 DOI: 10.1021/acsomega.1c04434] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/02/2021] [Indexed: 06/04/2023]
Abstract
Aluminum (Al) is an environmental neurotoxin to which humans are extensively exposed; however, the molecular mechanism of aluminum toxicity is unclear. Several studies have indicated that exposure to aluminum can cause abnormal phosphorylation of the tau protein. The purpose of this study was to investigate respectively the special molecular mechanism of abnormal regulation on synthesis and degradation of the tau protein induced by AlCl3 in cells of different species. The results of tau protein showed that the sites of abnormal tau phosphorylation induced by AlCl3 are Thr231, Ser262, and Ser396 in N2a cells. Meanwhile, the expressions of Thr181, Thr231, and Ser262 increased abnormally in SH-SY5Y cells. The result of the study showed that PP2A expression was high in N2a cells, while GSK-3β and PP2A in SH-SY5Y cells were involved in the synthesis process of abnormal tau phosphorylation induced by AlCl3. In N2a cells, the ubiquitin-proteasome pathway (UPP) mainly regulated tau phosphorylation at Ser262 and Ser396. Meanwhile, in SH-SY5Y cells, the UPP mainly regulated tau phosphorylation at Thr231 and Ser396. In summary, the UPP is involved in the degradation of Tau that is abnormally phosphorylated induced by AlCl3, but this process is site-specific and differs in cells of different species.
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Affiliation(s)
- Baolong Pan
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
- Sixth
Hospital of Shanxi Medical University (General Hospital of Tisco), Taiyuan 030001, China
| | - Xiaoting Lu
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
| | - Xiao Han
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
| | - Jiaping Huan
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
| | - Dan Gao
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
| | - Shuangjie Cui
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
| | - Xiaofen Ju
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
| | - Yunwei Zhang
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
| | - Shimeng Xu
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
| | - Jing Song
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
| | - Linping Wang
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
| | - Huifang Zhang
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
| | - Qiao Niu
- Department
of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, China
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4
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Dmitriev SE, Vladimirov DO, Lashkevich KA. A Quick Guide to Small-Molecule Inhibitors of Eukaryotic Protein Synthesis. BIOCHEMISTRY (MOSCOW) 2021; 85:1389-1421. [PMID: 33280581 PMCID: PMC7689648 DOI: 10.1134/s0006297920110097] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Eukaryotic ribosome and cap-dependent translation are attractive targets in the antitumor, antiviral, anti-inflammatory, and antiparasitic therapies. Currently, a broad array of small-molecule drugs is known that specifically inhibit protein synthesis in eukaryotic cells. Many of them are well-studied ribosome-targeting antibiotics that block translocation, the peptidyl transferase center or the polypeptide exit tunnel, modulate the binding of translation machinery components to the ribosome, and induce miscoding, premature termination or stop codon readthrough. Such inhibitors are widely used as anticancer, anthelmintic and antifungal agents in medicine, as well as fungicides in agriculture. Chemicals that affect the accuracy of stop codon recognition are promising drugs for the nonsense suppression therapy of hereditary diseases and restoration of tumor suppressor function in cancer cells. Other compounds inhibit aminoacyl-tRNA synthetases, translation factors, and components of translation-associated signaling pathways, including mTOR kinase. Some of them have antidepressant, immunosuppressive and geroprotective properties. Translation inhibitors are also used in research for gene expression analysis by ribosome profiling, as well as in cell culture techniques. In this article, we review well-studied and less known inhibitors of eukaryotic protein synthesis (with the exception of mitochondrial and plastid translation) classified by their targets and briefly describe the action mechanisms of these compounds. We also present a continuously updated database (http://eupsic.belozersky.msu.ru/) that currently contains information on 370 inhibitors of eukaryotic protein synthesis.
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Affiliation(s)
- S E Dmitriev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia. .,Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia.,Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - D O Vladimirov
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - K A Lashkevich
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
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5
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Martinez NW, Gómez FE, Matus S. The Potential Role of Protein Kinase R as a Regulator of Age-Related Neurodegeneration. Front Aging Neurosci 2021; 13:638208. [PMID: 33994991 PMCID: PMC8113420 DOI: 10.3389/fnagi.2021.638208] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 03/10/2021] [Indexed: 01/25/2023] Open
Abstract
There is a growing evidence describing a decline in adaptive homeostasis in aging-related diseases affecting the central nervous system (CNS), many of which are characterized by the appearance of non-native protein aggregates. One signaling pathway that allows cell adaptation is the integrated stress response (ISR), which senses stress stimuli through four kinases. ISR activation promotes translational arrest through the phosphorylation of the eukaryotic translation initiation factor 2 alpha (eIF2α) and the induction of a gene expression program to restore cellular homeostasis. However, depending on the stimulus, ISR can also induce cell death. One of the ISR sensors is the double-stranded RNA-dependent protein kinase [protein kinase R (PKR)], initially described as a viral infection sensor, and now a growing evidence supports a role for PKR on CNS physiology. PKR has been largely involved in the Alzheimer’s disease (AD) pathological process. Here, we reviewed the antecedents supporting the role of PKR on the efficiency of synaptic transmission and cognition. Then, we review PKR’s contribution to AD and discuss the possible participation of PKR as a player in the neurodegenerative process involved in aging-related pathologies affecting the CNS.
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Affiliation(s)
- Nicolás W Martinez
- Fundación Ciencia & Vida, Santiago, Chile.,Departamento de Ciencias Básicas, Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism, Santiago, Chile
| | | | - Soledad Matus
- Fundación Ciencia & Vida, Santiago, Chile.,Departamento de Ciencias Básicas, Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism, Santiago, Chile
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6
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Reimer L, Betzer C, Kofoed RH, Volbracht C, Fog K, Kurhade C, Nilsson E, Överby AK, Jensen PH. PKR kinase directly regulates tau expression and Alzheimer's disease-related tau phosphorylation. Brain Pathol 2020; 31:103-119. [PMID: 32716602 PMCID: PMC8018097 DOI: 10.1111/bpa.12883] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 06/12/2020] [Accepted: 07/07/2020] [Indexed: 12/28/2022] Open
Abstract
Deposition of extensively hyperphosphorylated tau in specific brain cells is a clear pathological hallmark in Alzheimer's disease and a number of other neurodegenerative disorders, collectively termed the tauopathies. Furthermore, hyperphosphorylation of tau prevents it from fulfilling its physiological role as a microtubule‐stabilizing protein and leaves it increasingly vulnerable to self‐assembly, suggestive of a central underlying role of hyperphosphorylation as a contributing factor in the etiology of these diseases. Via in vitro phosphorylation and regulation of kinase activity within cells and acute brain tissue, we reveal that the inflammation associated kinase, protein kinase R (PKR), directly phosphorylates numerous abnormal and disease‐modifying residues within tau including Thr181, Ser199/202, Thr231, Ser262, Ser396, Ser404 and Ser409. Similar to disease processes, these PKR‐mediated phosphorylations actively displace tau from microtubules in cells. In addition, PKR overexpression and knockdown, respectively, increase and decrease tau protein and mRNA levels in cells. This regulation occurs independent of noncoding transcriptional elements, suggesting an underlying mechanism involving intra‐exonic regulation of the tau‐encoding microtubule‐associated protein tau (MAPT) gene. Finally, acute encephalopathy in wild type mice, induced by intracranial Langat virus infection, results in robust inflammation and PKR upregulation accompanied by abnormally phosphorylated full‐length‐ and truncated tau. These findings indicate that PKR, independent of other kinases and upon acute brain inflammation, is capable of triggering pathological modulation of tau, which, in turn, might form the initial pathologic seed in several tauopathies such as Alzheimer's disease and Chronic traumatic encephalopathy where inflammation is severe.
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Affiliation(s)
- Lasse Reimer
- Danish Research Institute of Translational Neuroscience - DANDRITE, Aarhus University, Aarhus, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Cristine Betzer
- Danish Research Institute of Translational Neuroscience - DANDRITE, Aarhus University, Aarhus, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Rikke Hahn Kofoed
- Danish Research Institute of Translational Neuroscience - DANDRITE, Aarhus University, Aarhus, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | | | - Chaitanya Kurhade
- Department of Clinical Microbiology, Virology, Umeå University, Umea, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umea, Sweden
| | - Emma Nilsson
- Department of Clinical Microbiology, Virology, Umeå University, Umea, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umea, Sweden
| | - Anna K Överby
- Department of Clinical Microbiology, Virology, Umeå University, Umea, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umea, Sweden
| | - Poul Henning Jensen
- Danish Research Institute of Translational Neuroscience - DANDRITE, Aarhus University, Aarhus, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
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7
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Bond S, Lopez-Lloreda C, Gannon PJ, Akay-Espinoza C, Jordan-Sciutto KL. The Integrated Stress Response and Phosphorylated Eukaryotic Initiation Factor 2α in Neurodegeneration. J Neuropathol Exp Neurol 2020; 79:123-143. [PMID: 31913484 DOI: 10.1093/jnen/nlz129] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/07/2019] [Indexed: 02/06/2023] Open
Abstract
The proposed molecular mechanisms underlying neurodegenerative pathogenesis are varied, precluding the development of effective therapies for these increasingly prevalent disorders. One of the most consistent observations across neurodegenerative diseases is the phosphorylation of eukaryotic initiation factor 2α (eIF2α). eIF2α is a translation initiation factor, involved in cap-dependent protein translation, which when phosphorylated causes global translation attenuation. eIF2α phosphorylation is mediated by 4 kinases, which, together with their downstream signaling cascades, constitute the integrated stress response (ISR). While the ISR is activated by stresses commonly observed in neurodegeneration, such as oxidative stress, endoplasmic reticulum stress, and inflammation, it is a canonically adaptive signaling cascade. However, chronic activation of the ISR can contribute to neurodegenerative phenotypes such as neuronal death, memory impairments, and protein aggregation via apoptotic induction and other maladaptive outcomes downstream of phospho-eIF2α-mediated translation inhibition, including neuroinflammation and altered amyloidogenic processing, plausibly in a feed-forward manner. This review examines evidence that dysregulated eIF2a phosphorylation acts as a driver of neurodegeneration, including a survey of observations of ISR signaling in human disease, inspection of the overlap between ISR signaling and neurodegenerative phenomenon, and assessment of recent encouraging findings ameliorating neurodegeneration using developing pharmacological agents which target the ISR. In doing so, gaps in the field, including crosstalk of the ISR kinases and consideration of ISR signaling in nonneuronal central nervous system cell types, are highlighted.
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Affiliation(s)
- Sarah Bond
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Claudia Lopez-Lloreda
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Patrick J Gannon
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cagla Akay-Espinoza
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kelly L Jordan-Sciutto
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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8
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Bocai NI, Marcora MS, Belfiori-Carrasco LF, Morelli L, Castaño EM. Endoplasmic Reticulum Stress in Tauopathies: Contrasting Human Brain Pathology with Cellular and Animal Models. J Alzheimers Dis 2020; 68:439-458. [PMID: 30775999 DOI: 10.3233/jad-181021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The accumulation and spreading of protein tau in the human brain are major features of neurodegenerative disorders known as tauopathies. In addition to several subcellular abnormalities, tau aggregation within neurons seems capable of triggering endoplasmic reticulum (ER) stress and the consequent unfolded protein response (UPR). In metazoans, full activation of a complex ER-UPR network may restore proteostasis and ER function or, if stress cannot be solved, commit cells to apoptosis. Due to these alternative outcomes (survival or death), the pharmacological manipulation of ER-UPR has become the focus of potential therapies in many human diseases, including tauopathies. Here we update and analyze the experimental data from human brain, cellular, and animal models linking tau accumulation and ER-UPR. We further discuss mechanistic aspects and put the ER-UPR into perspective as a possible therapeutic target in this group of diseases.
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Affiliation(s)
- Nadia I Bocai
- Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.,Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - María S Marcora
- Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.,Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Lautaro F Belfiori-Carrasco
- Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.,Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Laura Morelli
- Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.,Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Eduardo M Castaño
- Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.,Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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9
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Fan R, Schrott LM, Snelling S, Felty J, Graham D, McGauly PL, Arnold T, Korneeva NL. Carbonyl-protein content increases in brain and blood of female rats after chronic oxycodone treatment. BMC Neurosci 2020; 21:4. [PMID: 31969118 PMCID: PMC6977314 DOI: 10.1186/s12868-020-0552-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 01/13/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Opioids are the most effective drugs commonly prescribed to treat pain. Due to their addictive nature, opioid pain relievers are now second to marijuana, ahead of cocaine with respect to dependence. Ours and other studies suggest potential toxic effects of chronic opioid administration leading to neuronal degeneration. It has been suggested that protein carbonylation may represent a sensitive biomarker of cellular degeneration. To evaluate whether prolonged oxycodone administration is associated with accumulation of protein aggregates that may contribute to neuronal degeneration we measured protein carbonylation levels in brain and also in blood plasma of rats after 30-days of 15 mg/kg daily oxycodone administration. RESULTS We observed a significant increase in the level of carbonylated proteins in rat brain cortex after 30-days of oxycodone treatment compare to that in water treated animals. Also, oxycodone treated rats demonstrated accumulation of insoluble carbonyl-protein aggregates in blood plasma. CONCLUSIONS Our data suggests that tests detecting insoluble carbonyl-protein aggregates in blood may serve as an inexpensive and minimally invasive method to monitor neuronal degeneration in patients with a history of chronic opioid use. Such methods could be used to detect toxic side effects of other medications and monitor progression of aging and neurodegenerative diseases.
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Affiliation(s)
- Ruping Fan
- Department of Emergency Medicine, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, USA
| | - Lisa M. Schrott
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, USA
| | - Stephen Snelling
- Department of Emergency Medicine, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, USA
| | - John Felty
- Department of Emergency Medicine, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, USA
| | - Derrel Graham
- Department of Emergency Medicine, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, USA
| | - Patrick L. McGauly
- Department of Emergency Medicine, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, USA
| | - Thomas Arnold
- Department of Emergency Medicine, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, USA
| | - Nadejda L. Korneeva
- Department of Emergency Medicine, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, USA
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, USA
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10
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Shabnam KR, Gangappa D, Philip GH. Zebrafish embryos exposed to deltamethrin exhibit abnormalities despite induced expression of related genes ( you, you-too, momo and u-boot). Toxicol Ind Health 2018; 35:11-19. [PMID: 30518298 DOI: 10.1177/0748233718807046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Evaluation of the toxic effects of a widely used synthetic pyrethroid, deltamethrin (DM), was carried out in this study. This pesticide is preferred for pest control because of its low environmental persistence and toxicity. We investigated the expression pattern of four genes, namely, you ( you), yot ( you-too), momo ( mom) and ubo ( u-boot) during early development of zebrafish, that is, from 12 hpf to 48 hpf stages. These stages are selected as most of the important developmental aspects take place during this period. All four genes are known to play a vital role in development of notochord and somites. To understand the effect of DM on development, embryos of 4 hpf stage were exposed to two concentrations (100 and 200 µg/L) of DM, and observations were made at 12, 24 and 48 hpf stages. Our earlier studies have shown phenotypic abnormalities such as notochord bending, tail deformation, yolk sac and pericardial edema, lightening of body and eye pigmentation and interfered in somite patterning, during these stages of development. Understanding the relationship of phenotypic abnormalities with these four genes has been our primary objective. These four genes were analyzed by Reverse transcription (RT)-polymerase chain reaction and intensity of the bands has shown induction in their expression after exposure to the toxicant. In spite of the expression of genes, it was noticed that DM caused abnormalities. It can be said from the results that translational pathway could have been affected.
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Affiliation(s)
- Kuder Reshma Shabnam
- 1 Department of Zoology, Sri Krishnadevaraya University, Anantapuram, Andhra Pradesh, India
| | - Dharmapuri Gangappa
- 2 Department of Animal Biology, School of life Sciences, University of Hyderabad, Telangana, India
| | - Gundala Harold Philip
- 2 Department of Animal Biology, School of life Sciences, University of Hyderabad, Telangana, India
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Hugon J, Mouton-Liger F, Dumurgier J, Paquet C. PKR involvement in Alzheimer's disease. ALZHEIMERS RESEARCH & THERAPY 2017; 9:83. [PMID: 28982375 PMCID: PMC5629792 DOI: 10.1186/s13195-017-0308-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 09/08/2017] [Indexed: 12/15/2022]
Abstract
BACKGROUND Brain lesions in Alzheimer's disease (AD) are characterized by Aβ accumulation, neurofibrillary tangles, and synaptic and neuronal vanishing. According to the amyloid cascade hypothesis, Aβ1-42 oligomers could trigger a neurotoxic cascade with kinase activation that leads to tau phosphorylation and neurodegeneration. Detrimental pathways that are associated with kinase activation could also be linked to the triggering of direct neuronal death, the production of free radicals, and neuroinflammation. RESULTS Among these kinases, PKR (eukaryotic initiation factor 2α kinase 2) is a pro-apoptotic enzyme that inhibits translation and that has been implicated in several molecular pathways that lead to AD brain lesions and disturbed memory formation. PKR accumulates in degenerating neurons and is activated by Aβ1-42 neurotoxicity. It might modulate Aβ synthesis through BACE 1 induction. PKR is increased in cerebrospinal fluid from patients with AD and mild cognitive impairment and can induce the activation of pro-inflammatory pathways leading to TNFα and IL1-β production. In addition, experimentally, PKR seems to down-regulate the molecular processes of memory consolidation. This review highlights the major findings linking PKR and abnormal brain metabolism associated with AD lesions. CONCLUSIONS Studying the detrimental role of PKR signaling in AD could pave the way for a neuroprotective strategy in which PKR inhibition could reduce neuronal demise and alleviate cognitive decline as well as the cumbersome burden of AD for patients.
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Affiliation(s)
- Jacques Hugon
- Center of Cognitive Neurology and Inserm U942 Lariboisière Hospital AP-HP University Paris Diderot, 75010, Paris, France. .,Center of Cognitive Neurology, Lariboisière FW Hospital, 200 rue du Faubourg Saint Denis, 75010, Paris, France.
| | | | - Julien Dumurgier
- Center of Cognitive Neurology and Inserm U942 Lariboisière Hospital AP-HP University Paris Diderot, 75010, Paris, France
| | - Claire Paquet
- Center of Cognitive Neurology and Inserm U942 Lariboisière Hospital AP-HP University Paris Diderot, 75010, Paris, France
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12
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Bellato HM, Hajj GNM. Translational control by eIF2α in neurons: Beyond the stress response. Cytoskeleton (Hoboken) 2016; 73:551-565. [PMID: 26994324 DOI: 10.1002/cm.21294] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/14/2016] [Accepted: 03/14/2016] [Indexed: 12/21/2022]
Abstract
The translation of mRNAs is a tightly controlled process that responds to multiple signaling pathways. In neurons, this control is also exerted locally due to the differential necessity of proteins in axons and dendrites. The phosphorylation of the alpha subunit of the translation initiation factor 2 (eIF2α) is one of the mechanisms of translational control. The phosphorylation of eIF2α has classically been viewed as a stress response, halting translation initiation. However, in the nervous system this type of regulation has been related to other mechanisms besides stress response, such as behavior, memory consolidation and nervous system development. Additionally, neurodegenerative diseases have a major stress component, thus eIF2α phosphorylation plays a preeminent role and its modulation is currently viewed as a new opportunity for therapeutic interventions. This review consolidates current information regarding eIF2α phosphorylation in neurons and its impact in neurodegenerative diseases. © 2016 Wiley Periodicals, Inc.
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Zinc regulates expression of IL-23 p19 mRNA via activation of eIF2α/ATF4 axis in HAPI cells. Biometals 2015; 28:891-902. [PMID: 26174742 DOI: 10.1007/s10534-015-9874-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 07/03/2015] [Indexed: 12/22/2022]
Abstract
Zinc (Zn(2+)) is considered to be one of the factors aggravating brain damage after cerebral ischemia. Since Zn(2+) activates microglia, immune cells in the brain, this metal is proposed to modulate neuroinflammatory responses in the post-ischemic brain. Interleukin (IL)-23 is a heterodimeric cytokine composed of the p19 subunit unique to IL-23 and the p40 subunit common to IL-12. IL-23 has been shown to play a critical role in the progression of ischemic brain injury. However, whether Zn(2+) participates in the expression of IL-23 in microglia remains unknown. In this study, we examined the effect of Zn(2+) on IL-23 p19 mRNA expression using rat immortalized microglia HAPI cells. Exposure to Zn(2+) dose- and time-dependently induced the expression of IL-23 p19 mRNA in HAPI cells. Inhibitors of MAPK and NF-κB pathways failed to suppress this induction. Interestingly, we found that Zn(2+) stimulated the phosphorylation of eIF2α and promoted the nuclear accumulation of activating transcription factor 4 (ATF4). Treatment with salubrinal, an eIF2α dephosphorylation inhibitor, enhanced Zn(2+)-induced ATF4 accumulation and IL-23 p19 mRNA expression. In addition, reporter assay using the IL-23 p19 promoter region revealed that ATF4 directly transactivated IL-23 p19 promoter and that dominant-negative ATF4 suppressed Zn(2+)-induced activation of IL-23 p19 promoter. Taken together, these findings suggest that Zn(2+) up-regulates expression of the IL-23 p19 gene via the eIF2α/ATF4 axis in HAPI cells.
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Dlugos CA. ATF6 and caspase 12 expression in Purkinje neurons in acute slices from adult, ethanol-fed rats. Brain Res 2014; 1577:11-20. [PMID: 24976582 DOI: 10.1016/j.brainres.2014.06.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 06/19/2014] [Accepted: 06/21/2014] [Indexed: 12/30/2022]
Abstract
The purpose of this study was to determine, whether previously reported ethanol-induced alterations to the smooth endoplasmic reticulum (SER), predispose Purkinje neurons (PN) to thapsigargin-induced endoplasmic reticulum (ER) stress. Thapsigargin blocks the sarco/endoplasmic Ca(2+) ATPase pump (SERCA 2), depleting the SER of calcium. Forty-one, eight month old Fischer 344 male rats were treated with either the AIN (American Institute of Nutrition) liquid control or ethanol diets for 10 (n=14), 20 (n=10), or 40(n=17) weeks. At the end of treatment, acute cerebellar slices were prepared by standard means. Cerebellar slices were treated with thapsigargin or as controls for three hours in oxygenated (95% CO2, 5% O2) ACSF (artificial cerebrospinal fluid). Slices were then fixed in 4% paraformaldehyde and sectioned on a freezing microtome. Free floating sections were stained with antibodies against activating transcription factor 6 (ATF6) or activated caspase 12 and calbindin. Results showed a significant increase in the activated caspase+PN dendrites in the EF rats along with a significant interaction due to enhanced expression of activated caspase 12 at 20 weeks. The density of ATF6 labeling was not different between the EF and PF groups and was confined to the PN soma. The finding of activated caspase and ATF6 expression in PN within both the EF and PF groups supports the finding of thapsigargin-induced ER stress. The finding of increased activated caspase 12 in the dendrites supports an increased tendency to ER stress and other dendritic deficits in the ethanol rats.
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Affiliation(s)
- Cynthia A Dlugos
- Department of Pathology and Anatomical Sciences, 206 Farber Hall, School of Medicine and Biomedical Sciences, University at Buffalo, NY 14214-3000, USA.
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Zhang NS, Li HY, Liu JS, Yang WD. Gene expression profiles in zebrafish (Danio rerio) liver after acute exposure to okadaic acid. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2014; 37:791-802. [PMID: 24637248 DOI: 10.1016/j.etap.2014.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 02/05/2014] [Accepted: 02/06/2014] [Indexed: 06/03/2023]
Abstract
Okadaic acid (OA), a main component of diarrheic shellfish poisoning (DSP) toxins, is a strong and specific inhibitor of the serine/threonine protein phosphatases PP1 and PP2A. However, not all of the OA-induced effects can be explained by this phosphatase inhibition, and controversial results on OA are increasing. To provide clues on potential mechanisms of OA other than phosphatase inhibition, here, acute toxicity of OA was evaluated in zebrafish, and changes in gene expression in zebrafish liver tissues upon exposure to OA were observed by microarray. The i.p. ED50 (6 h) of OA on zebrafish was 1.54 μg OA/g body weight (bw). Among the genes analyzed on the zebrafish array, 55 genes were significantly up-regulated and 36 down-regulated in the fish liver tissue upon exposure to 0.176 μg OA/g bw (low-dose group, LD) compared with the low ethanol control (LE). However, there were no obvious functional clusters for them. On the contrary, fish exposure to 1.760 μg OA/g bw (high-dose group, HD) yielded a great number of differential expressed genes (700 up and 285 down) compared with high ethanol control (HE), which clustered in several functional terms such as p53 signaling pathway, Wnt signaling pathway, glutathione metabolism and protein processing in endoplasmic reticulum, etc. These genes were involved in protein phosphatase activity, translation factor activity, heat shock protein binding, as well as transmembrane transporter activity. Our findings may give some useful information on the pathways of OA-induced injury in fish.
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Affiliation(s)
- Nai-sheng Zhang
- College of Life Science and Technology, Jinan University, Guangzhou 510632, PR China; Wageningen University and Research Centre, Centre for Water and Climate, Alterra, PO Box 47, 6700AA Wageningen, The Netherlands
| | - Hong-ye Li
- College of Life Science and Technology, Jinan University, Guangzhou 510632, PR China; Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, P. R. China
| | - Jie-sheng Liu
- College of Life Science and Technology, Jinan University, Guangzhou 510632, PR China; Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, P. R. China
| | - Wei-dong Yang
- College of Life Science and Technology, Jinan University, Guangzhou 510632, PR China; Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, P. R. China.
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Suppression of eIF2α kinases alleviates Alzheimer's disease-related plasticity and memory deficits. Nat Neurosci 2013; 16:1299-305. [PMID: 23933749 PMCID: PMC3756900 DOI: 10.1038/nn.3486] [Citation(s) in RCA: 421] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 06/27/2013] [Indexed: 12/11/2022]
Abstract
Expression of long-lasting synaptic plasticity and long-term memory requires new protein synthesis, which can be repressed by phosphorylation of eukaryotic initiation factor 2α subunit (eIF2α). It was reported previously that eIF2α phosphorylation is elevated in the brains of Alzheimer’s disease (AD) patients and AD model mice. Therefore, we determined whether suppressing eIF2α kinases could alleviate synaptic plasticity and memory deficits in AD model mice. The genetic deletion of the eIF2α kinase PERK prevented enhanced eIF2α phosphorylation, as well as deficits in protein synthesis, synaptic plasticity, and spatial memory in APP/PS1 AD model mice. Similarly, deletion of another eIF2α kinase, GCN2, prevented impairments of synaptic plasticity and spatial memory defects displayed in the APP/PS1 mice. Our findings implicate aberrant eIF2α phosphorylation as a novel molecular mechanism underlying AD-related synaptic pathophysioloy and memory dysfunction and suggest that PERK and GCN2 are potential therapeutic targets for the treatment of individuals with AD.
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Medina M, Avila J, Villanueva N. Use of okadaic acid to identify relevant phosphoepitopes in pathology: a focus on neurodegeneration. Mar Drugs 2013; 11:1656-68. [PMID: 23697949 PMCID: PMC3707166 DOI: 10.3390/md11051656] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 04/02/2013] [Accepted: 04/16/2013] [Indexed: 12/24/2022] Open
Abstract
Protein phosphorylation is involved in the regulation of a wide variety of physiological processes and is the result of a balance between protein kinase and phosphatase activities. Biologically active marine derived compounds have been shown to represent an interesting source of novel compounds that could modify that balance. Among them, the marine toxin and tumor promoter, okadaic acid (OA), has been shown as an inhibitor of two of the main cytosolic, broad-specificity protein phosphatases, PP1 and PP2A, thus providing an excellent cell-permeable probe for examining the role of protein phosphorylation, and PP1 and PP2A in particular, in any physiological or pathological process. In the present work, we review the use of okadaic acid to identify specific phosphoepitopes mainly in proteins relevant for neurodegeneration. We will specifically highlight those cases of highly dynamic phosphorylation-dephosphorylation events and the ability of OA to block the high turnover phosphorylation, thus allowing the detection of modified residues that could be otherwise difficult to identify. Finally, its effect on tau hyperhosphorylation and its relevance in neurodegenerative pathologies such as Alzheimer’s disease and related dementia will be discussed.
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Affiliation(s)
- Miguel Medina
- CIBERNED (Center for Networked Biomedical Research in Neurodegenerative Diseases), Valderrebollo 5, Madrid 28041, Spain; E-Mail:
| | - Jesús Avila
- CIBERNED (Center for Networked Biomedical Research in Neurodegenerative Diseases), Valderrebollo 5, Madrid 28041, Spain; E-Mail:
- Center of Molecular Biology “Severo Ochoa” CSIC-UAM, Nicolás Cabrera 1, Madrid 28049, Spain
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +34-91-196-4803; Fax: +34-91-196-4715
| | - Nieves Villanueva
- National Center of Microbiology (CNM), Carlos III Institute of Health (ISCIII), Crta. Majadahonda-Pozuelo km 2, Majadahonda, Madrid 28220, Spain; E-Mail:
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Kang SW, Yoon SY, Park JY, Kim DH. Unglycosylated clusterin variant accumulates in the endoplasmic reticulum and induces cytotoxicity. Int J Biochem Cell Biol 2012. [PMID: 23201481 DOI: 10.1016/j.biocel.2012.11.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Clusterin is a stress-responsive and highly glycosylated secretory protein that plays cytoprotective role in most body fluids. In addition to extracellular clusterin, several intracellular clusterin variants that are rather cytotoxic have been recently uncovered under diverse pathological conditions. Although these variants revealed heterogeneity in their glycan modification, its significance in many diseases remains to be validated. Here, we found that clusterin is differentially metabolized by two well-characterized ER stress inducers. Thapsigargin induced retrotranslocation and rapid degradation of clusterin from the endoplasmic reticulum, whereas tunicamycin failed to degrade but rather retained clusterin in the endoplasmic reticulum. Important sorting determinant for these processes proved to be N-glycan moieties that are required for the prevention of terminal misfolding and aggregation of clusterin in the endoplasmic reticulum. This study provides a mechanistic insight into the generation of noble cytotoxic variant of intracellular clusterin and an idea about molecular pathogenesis of diseases associated with chronic endoplasmic reticulum stress, such as neurodegeneration.
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Affiliation(s)
- Sang-Wook Kang
- Graduate School, University of Ulsan College of Medicine, Seoul, Republic of Korea.
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Increased cerebrospinal fluid levels of double-stranded RNA-dependant protein kinase in Alzheimer's disease. Biol Psychiatry 2012; 71:829-35. [PMID: 22281122 DOI: 10.1016/j.biopsych.2011.11.031] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 11/16/2011] [Accepted: 11/16/2011] [Indexed: 12/31/2022]
Abstract
BACKGROUND The pathological hallmarks of Alzheimer's disease (AD) include accumulation of amyloid-β (Aß) peptide forming extracellular senile plaques, neurofibrillary tangles made of hyperphosphorylated tau protein with neuronal loss. Aβ peptide (1-42), total tau (T-tau), and phosphorylated tau at threonine 181 (p181tau) levels in the cerebrospinal fluid (CSF) are now validated biomarkers. The proapoptotic kinase R (PKR), is activated by Aβ accumulates in degenerating neurons in AD brains and controls protein synthesis and indirectly tau phosphorylation. METHODS In a prospective cohort study, the CSF of 91 patients were studied (AD: 45; amnestic mild cognitive impairment: 11; neurological disease control subjects [NDC]: 35). The levels of total PKR (T-PKR), phosphorylated PKR (pPKR), Aß 1-42, T-tau, and p181tau were assessed by immunoblotting or enzyme-linked immunosorbent assay methods. Receivers operating characteristic curves were used to examine the discriminatory power of T-PKR, pPKR, and pPKR/T-PKR ratio between AD and NDC patients. RESULTS Total PKR and pPKR concentrations were elevated in AD and amnestic mild cognitive impairment subjects. We have determined a pPKR value (optical density units) that could discriminate AD patients from control subjects with a sensitivity of 91.1% and a specificity of 94.3%. Among AD patients, T-PKR and pPKR levels correlate with CSF p181tau levels. Some AD patients with normal CSF Aß, T-tau, or p181tau levels had abnormal T-PKR and pPKR levels. CONCLUSIONS The evaluation of CSF T-PKR and pPKR can discriminate between AD patients and NDC and could help to improve the biochemical diagnosis of AD.
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Increased phosphorylation of dynamin-related protein 1 and mitochondrial fission in okadaic acid-treated neurons. Brain Res 2012; 1454:100-10. [DOI: 10.1016/j.brainres.2012.03.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 03/02/2012] [Accepted: 03/04/2012] [Indexed: 01/25/2023]
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Kim DH, Huh JW, Jang M, Suh JH, Kim TW, Park JS, Yoon SY. Sitagliptin increases tau phosphorylation in the hippocampus of rats with type 2 diabetes and in primary neuron cultures. Neurobiol Dis 2012; 46:52-8. [DOI: 10.1016/j.nbd.2011.12.043] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 12/13/2011] [Accepted: 12/23/2011] [Indexed: 01/03/2023] Open
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Park J, Chung S, An H, Kim J, Seo J, Kim DH, Yoon SY. Haloperidol and clozapine block formation of autophagolysosomes in rat primary neurons. Neuroscience 2012; 209:64-73. [PMID: 22390943 DOI: 10.1016/j.neuroscience.2012.02.035] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/16/2012] [Accepted: 02/16/2012] [Indexed: 12/13/2022]
Abstract
Early intervention and maintenance treatment for schizophrenia patients may prolong the duration of exposure to antipsychotic agents; however, there have been few studies on the neurotoxicity of these agents. Here, we investigated the effects of antipsychotics on cell viability and autophagy in rat primary neurons. Cultured cortical neurons obtained from rat embryos were treated with various concentrations of haloperidol and clozapine, and the neuronal toxicity was assessed by measuring lactate dehydrogenase (LDH) activity and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Autophagosomes were quantitated by measuring the level of microtubule-associated protein 1A/1B-light chain 3 (LC3-II) by Western blot and immunofluorescence staining. Autophagic flux was assayed using bafilomycin A1 and GFP-mCherry-LC3 transfection. Haloperidol and clozapine decreased the viability of neurons in vitro in a concentration- and time-dependent manner. We also observed increased accumulation of autophagosomes after antipsychotic treatment. Using bafilomycin A1 and GFP-mCherry-LC3 transfection, we discovered that haloperidol and clozapine inhibited autophagosome turnover resulting in a dysfunctional autophagic process, including impaired lysosomal fusion. Together, these results suggest that haloperidol and clozapine negatively affect neuronal viability, possibly by blocking autophagolysosome formation.
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Affiliation(s)
- J Park
- Department of Psychiatry, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
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