1
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de Cavanagh EMV, Inserra F, Ferder L. Renin-angiotensin system inhibitors positively impact on multiple aging regulatory pathways: Could they be used to protect against human aging? Physiol Rep 2024; 12:e16094. [PMID: 38924381 PMCID: PMC11200104 DOI: 10.14814/phy2.16094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 05/18/2024] [Accepted: 05/18/2024] [Indexed: 06/28/2024] Open
Abstract
The renin-angiotensin system (RAS)-a classical blood pressure regulator-largely contributes to healthy organ development and function. Besides, RAS activation promotes age-related changes and age-associated diseases, which are attenuated/abolished by RAS-blockade in several mammalian species. RAS-blockers also increase rodent lifespan. In previous work, we discussed how RAS-blockade downregulates mTOR and growth hormone/IGF-1 signaling, and stimulates AMPK activity (together with klotho, sirtuin, and vitamin D-receptor upregulation), and proposed that at least some of RAS-blockade's aging benefits are mediated through regulation of these intermediaries and their signaling to mitochondria. Here, we included RAS-blockade's impact on other aging regulatory pathways, that is, TGF-ß, NF-kB, PI3K, MAPK, PKC, Notch, and Wnt, all of which affect mitochondria. No direct evidence is available on RAS/RAS-blockade-aging regulatory pathway-mitochondria interactions. However, existing results allow to conjecture that RAS-blockers neutralize mitochondrial dysfunction by acting on the discussed pathways. The reviewed evidence led us to propose that the foundation is laid for conducting clinical trials aimed at testing whether angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB)-even at subclinical doses-offer the possibility to live longer and in better health. As ACEi and ARB are low cost and well-tolerated anti-hypertension therapies in use for over 35 years, investigating their administration to attenuate/prevent aging effects seems simple to implement.
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Affiliation(s)
| | - Felipe Inserra
- Department of MedicineMaimonides UniversityBuenos AiresArgentina
- Master of Vascular Mechanics and Arterial Hypertension, Postgraduate DepartmentAustral UniversityPilarArgentina
| | - León Ferder
- Department of MedicineMaimonides UniversityBuenos AiresArgentina
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2
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Shen M, Sirois CL, Guo Y, Li M, Dong Q, Méndez-Albelo NM, Gao Y, Khullar S, Kissel L, Sandoval SO, Wolkoff NE, Huang SX, Xu Z, Bryan JE, Contractor AM, Korabelnikov T, Glass IA, Doherty D, Levine JE, Sousa AMM, Chang Q, Bhattacharyya A, Wang D, Werling DM, Zhao X. Species-specific FMRP regulation of RACK1 is critical for prenatal cortical development. Neuron 2023; 111:3988-4005.e11. [PMID: 37820724 PMCID: PMC10841112 DOI: 10.1016/j.neuron.2023.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/20/2023] [Accepted: 09/13/2023] [Indexed: 10/13/2023]
Abstract
Fragile X messenger ribonucleoprotein 1 protein (FMRP) deficiency leads to fragile X syndrome (FXS), an autism spectrum disorder. The role of FMRP in prenatal human brain development remains unclear. Here, we show that FMRP is important for human and macaque prenatal brain development. Both FMRP-deficient neurons in human fetal cortical slices and FXS patient stem cell-derived neurons exhibit mitochondrial dysfunctions and hyperexcitability. Using multiomics analyses, we have identified both FMRP-bound mRNAs and FMRP-interacting proteins in human neurons and unveiled a previously unknown role of FMRP in regulating essential genes during human prenatal development. We demonstrate that FMRP interaction with CNOT1 maintains the levels of receptor for activated C kinase 1 (RACK1), a species-specific FMRP target. Genetic reduction of RACK1 leads to both mitochondrial dysfunctions and hyperexcitability, resembling FXS neurons. Finally, enhancing mitochondrial functions rescues deficits of FMRP-deficient cortical neurons during prenatal development, demonstrating targeting mitochondrial dysfunction as a potential treatment.
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Affiliation(s)
- Minjie Shen
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Carissa L Sirois
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Yu Guo
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Meng Li
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Qiping Dong
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Natasha M Méndez-Albelo
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; Molecular Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Yu Gao
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Saniya Khullar
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Departments of Biostatistics and Medical Informatics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Lee Kissel
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Soraya O Sandoval
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Natalie E Wolkoff
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Sabrina X Huang
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Zhiyan Xu
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; Graduate Program in Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Jonathan E Bryan
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Departments of Biostatistics and Medical Informatics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Amaya M Contractor
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Tomer Korabelnikov
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Ian A Glass
- Birth Defects Research Laboratory, University of Washington, Seattle, WA 98195, USA
| | - Dan Doherty
- Birth Defects Research Laboratory, University of Washington, Seattle, WA 98195, USA
| | - Jon E Levine
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; Wisconsin National Primate Research Center, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - André M M Sousa
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Qiang Chang
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neurology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA; Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Anita Bhattacharyya
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Daifeng Wang
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Departments of Biostatistics and Medical Informatics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Donna M Werling
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Xinyu Zhao
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA.
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3
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Oudart M, Avila-Gutierrez K, Moch C, Dossi E, Milior G, Boulay AC, Gaudey M, Moulard J, Lombard B, Loew D, Bemelmans AP, Rouach N, Chapat C, Cohen-Salmon M. The ribosome-associated protein RACK1 represses Kir4.1 translation in astrocytes and influences neuronal activity. Cell Rep 2023; 42:112456. [PMID: 37126448 DOI: 10.1016/j.celrep.2023.112456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 02/10/2023] [Accepted: 04/16/2023] [Indexed: 05/02/2023] Open
Abstract
The regulation of translation in astrocytes, the main glial cells in the brain, remains poorly characterized. We developed a high-throughput proteomics screen for polysome-associated proteins in astrocytes and focused on ribosomal protein receptor of activated protein C kinase 1 (RACK1), a critical factor in translational regulation. In astrocyte somata and perisynaptic astrocytic processes (PAPs), RACK1 preferentially binds to a number of mRNAs, including Kcnj10, encoding the inward-rectifying potassium (K+) channel Kir4.1. By developing an astrocyte-specific, conditional RACK1 knockout mouse model, we show that RACK1 represses production of Kir4.1 in hippocampal astrocytes and PAPs. Upregulation of Kir4.1 in the absence of RACK1 increases astrocytic Kir4.1-mediated K+ currents and volume. It also modifies neuronal activity attenuating burst frequency and duration. Reporter-based assays reveal that RACK1 controls Kcnj10 translation through the transcript's 5' untranslated region. Hence, translational regulation by RACK1 in astrocytes represses Kir4.1 expression and influences neuronal activity.
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Affiliation(s)
- Marc Oudart
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Katia Avila-Gutierrez
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Clara Moch
- Laboratoire de Biochimie, Ecole Polytechnique, CNRS, Université Paris-Saclay, Palaiseau, France
| | - Elena Dossi
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Giampaolo Milior
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Anne-Cécile Boulay
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Mathis Gaudey
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Julien Moulard
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Bérangère Lombard
- CurieCoreTech Spectrométrie de Masse Protéomique, Institut Curie, University PSL, Paris, France
| | - Damarys Loew
- CurieCoreTech Spectrométrie de Masse Protéomique, Institut Curie, University PSL, Paris, France
| | - Alexis-Pierre Bemelmans
- CEA, Institut de Biologie François Jacob, Molecular Imaging Research Center (MIRCen), CNRS, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Clément Chapat
- Laboratoire de Biochimie, Ecole Polytechnique, CNRS, Université Paris-Saclay, Palaiseau, France
| | - Martine Cohen-Salmon
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France.
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4
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Masi M, Biundo F, Fiou A, Racchi M, Pascale A, Buoso E. The Labyrinthine Landscape of APP Processing: State of the Art and Possible Novel Soluble APP-Related Molecular Players in Traumatic Brain Injury and Neurodegeneration. Int J Mol Sci 2023; 24:ijms24076639. [PMID: 37047617 PMCID: PMC10095589 DOI: 10.3390/ijms24076639] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/21/2023] [Accepted: 03/29/2023] [Indexed: 04/05/2023] Open
Abstract
Amyloid Precursor Protein (APP) and its cleavage processes have been widely investigated in the past, in particular in the context of Alzheimer’s Disease (AD). Evidence of an increased expression of APP and its amyloidogenic-related cleavage enzymes, β-secretase 1 (BACE1) and γ-secretase, at the hit axon terminals following Traumatic Brain Injury (TBI), firstly suggested a correlation between TBI and AD. Indeed, mild and severe TBI have been recognised as influential risk factors for different neurodegenerative diseases, including AD. In the present work, we describe the state of the art of APP proteolytic processing, underlining the different roles of its cleavage fragments in both physiological and pathological contexts. Considering the neuroprotective role of the soluble APP alpha (sAPPα) fragment, we hypothesised that sAPPα could modulate the expression of genes of interest for AD and TBI. Hence, we present preliminary experiments addressing sAPPα-mediated regulation of BACE1, Isthmin 2 (ISM2), Tetraspanin-3 (TSPAN3) and the Vascular Endothelial Growth Factor (VEGFA), each discussed from a biological and pharmacological point of view in AD and TBI. We finally propose a neuroprotective interaction network, in which the Receptor for Activated C Kinase 1 (RACK1) and the signalling cascade of PKCβII/nELAV/VEGF play hub roles, suggesting that vasculogenic-targeting therapies could be a feasible approach for vascular-related brain injuries typical of AD and TBI.
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Affiliation(s)
- Mirco Masi
- Computational and Chemical Biology, Italian Institute of Technology, Via Morego 30, 16163 Genova, Italy
| | - Fabrizio Biundo
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA
| | - André Fiou
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Via Taramelli 12/14, 27100 Pavia, Italy
| | - Marco Racchi
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Via Taramelli 12/14, 27100 Pavia, Italy
| | - Alessia Pascale
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Via Taramelli 12/14, 27100 Pavia, Italy
| | - Erica Buoso
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Via Taramelli 12/14, 27100 Pavia, Italy
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA
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5
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Tomaiuolo P, Piras IS, Sain SB, Picinelli C, Baccarin M, Castronovo P, Morelli MJ, Lazarevic D, Scattoni ML, Tonon G, Persico AM. RNA sequencing of blood from sex- and age-matched discordant siblings supports immune and transcriptional dysregulation in autism spectrum disorder. Sci Rep 2023; 13:807. [PMID: 36646776 PMCID: PMC9842630 DOI: 10.1038/s41598-023-27378-w] [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: 08/27/2022] [Accepted: 01/02/2023] [Indexed: 01/18/2023] Open
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental condition with onset in early childhood, still diagnosed only through clinical observation due to the lack of laboratory biomarkers. Early detection strategies would be especially useful in screening high-risk newborn siblings of children already diagnosed with ASD. We performed RNA sequencing on peripheral blood, comparing 27 pairs of ASD children vs their sex- and age-matched unaffected siblings. Differential gene expression profiling, performed applying an unpaired model found two immune genes, EGR1 and IGKV3D-15, significantly upregulated in ASD patients (both p adj = 0.037). Weighted gene correlation network analysis identified 18 co-expressed modules. One of these modules was downregulated among autistic individuals (p = 0.035) and a ROC curve using its eigengene values yielded an AUC of 0.62. Genes in this module are primarily involved in transcriptional control and its hub gene, RACK1, encodes for a signaling protein critical for neurodevelopment and innate immunity, whose expression is influenced by various hormones and known "endocrine disruptors". These results indicate that transcriptomic biomarkers can contribute to the sensitivity of an intra-familial multimarker panel for ASD and provide further evidence that neurodevelopment, innate immunity and transcriptional regulation are key to ASD pathogenesis.
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Affiliation(s)
| | - Ignazio Stefano Piras
- Neurogenomics Division, The Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Simona Baghai Sain
- Center for Translational Genomics and Bioinformatics, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Chiara Picinelli
- Mafalda Luce Center for Pervasive Developmental Disorders, Milan, Italy
| | - Marco Baccarin
- Mafalda Luce Center for Pervasive Developmental Disorders, Milan, Italy.,Department of Genetics, Synlab Suisse SA, Bioggio, Switzerland
| | - Paola Castronovo
- Mafalda Luce Center for Pervasive Developmental Disorders, Milan, Italy
| | - Marco J Morelli
- Center for Translational Genomics and Bioinformatics, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Dejan Lazarevic
- Center for Translational Genomics and Bioinformatics, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maria Luisa Scattoni
- Research Coordination and Support Service, Istituto Superiore di Sanità, Rome, Italy
| | - Giovanni Tonon
- Center for Translational Genomics and Bioinformatics, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Antonio M Persico
- Child and Adolescent Neuropsychiatry Program, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 287, 41125, Modena, Italy.
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6
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Proteostasis Deregulation in Neurodegeneration and Its Link with Stress Granules: Focus on the Scaffold and Ribosomal Protein RACK1. Cells 2022; 11:cells11162590. [PMID: 36010666 PMCID: PMC9406587 DOI: 10.3390/cells11162590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/09/2022] [Accepted: 08/17/2022] [Indexed: 12/12/2022] Open
Abstract
The role of protein misfolding, deposition, and clearance has been the dominant topic in the last decades of investigation in the field of neurodegeneration. The impairment of protein synthesis, along with RNA metabolism and RNA granules, however, are significantly emerging as novel potential targets for the comprehension of the molecular events leading to neuronal deficits. Indeed, defects in ribosome activity, ribosome stalling, and PQC—all ribosome-related processes required for proteostasis regulation—can contribute to triggering stress conditions and promoting the formation of stress granules (SGs) that could evolve in the formation of pathological granules, usually occurring during neurodegenerating effects. In this review, the interplay between proteostasis, mRNA metabolism, and SGs has been explored in a neurodegenerative context with a focus on Alzheimer’s disease (AD), although some defects in these same mechanisms can also be found in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), which are discussed here. Finally, we highlight the role of the receptor for activated C kinase 1 (RACK1) in these pathologies and note that, besides its well characterized function as a scaffold protein, it has an important role in translation and can associate to stress granules (SGs) determining cell fate in response to diverse stress stimuli.
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7
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van der Westhuizen ET, Choy KHC, Valant C, McKenzie-Nickson S, Bradley SJ, Tobin AB, Sexton PM, Christopoulos A. Fine Tuning Muscarinic Acetylcholine Receptor Signaling Through Allostery and Bias. Front Pharmacol 2021; 11:606656. [PMID: 33584282 PMCID: PMC7878563 DOI: 10.3389/fphar.2020.606656] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/30/2020] [Indexed: 12/18/2022] Open
Abstract
The M1 and M4 muscarinic acetylcholine receptors (mAChRs) are highly pursued drug targets for neurological diseases, in particular for Alzheimer's disease and schizophrenia. Due to high sequence homology, selective targeting of any of the M1-M5 mAChRs through the endogenous ligand binding site has been notoriously difficult to achieve. With the discovery of highly subtype selective mAChR positive allosteric modulators in the new millennium, selectivity through targeting an allosteric binding site has opened new avenues for drug discovery programs. However, some hurdles remain to be overcome for these promising new drug candidates to progress into the clinic. One challenge is the potential for on-target side effects, such as for the M1 mAChR where over-activation of the receptor by orthosteric or allosteric ligands can be detrimental. Therefore, in addition to receptor subtype selectivity, a drug candidate may need to exhibit a biased signaling profile to avoid such on-target adverse effects. Indeed, recent studies in mice suggest that allosteric modulators for the M1 mAChR that bias signaling toward specific pathways may be therapeutically important. This review brings together details on the signaling pathways activated by the M1 and M4 mAChRs, evidence of biased agonism at these receptors, and highlights pathways that may be important for developing new subtype selective allosteric ligands to achieve therapeutic benefit.
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Affiliation(s)
- Emma T. van der Westhuizen
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
| | - K. H. Christopher Choy
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
| | - Celine Valant
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
| | - Simon McKenzie-Nickson
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
| | - Sophie J. Bradley
- Centre for Translational Pharmacology, Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, United Kingdom
| | - Andrew B. Tobin
- Centre for Translational Pharmacology, Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, United Kingdom
| | - Patrick M. Sexton
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute for Pharmaceutical Research, Monash University, Parkville, VIC, Australia
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8
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Fagiani F, Lanni C, Racchi M, Pascale A, Govoni S. Amyloid-β and Synaptic Vesicle Dynamics: A Cacophonic Orchestra. J Alzheimers Dis 2020; 72:1-14. [PMID: 31561377 DOI: 10.3233/jad-190771] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
It is now more than two decades since amyloid-β (Aβ), the proteolytic product of the amyloid-β protein precursor (AβPP), was first demonstrated to be a normal and soluble product of neuronal metabolism. To date, despite a growing body of evidence suggests its regulatory role on synaptic function, the exact cellular and molecular pathways involved in Aβ-driven synaptic effects remain elusive. This review provides an overview of the mounting evidence showing Aβ-mediated effects on presynaptic functions and neurotransmitter release from axon terminals, focusing on its interaction with synaptic vesicle cycle. Indeed, Aβ peptides have been found to interact with key presynaptic scaffold proteins and kinases affecting the consequential steps of the synaptic vesicle dynamics (e.g., synaptic vesicles exocytosis, endocytosis, and trafficking). Defects in the fine-tuning of synaptic vesicle cycle by Aβ and deregulation of key molecules and kinases, which orchestrate synaptic vesicle availability, may alter synaptic homeostasis, possibly contributing to synaptic loss and cognitive decline. Elucidating the presynaptic mechanisms by which Aβ regulate synaptic transmission is fundamental for a deeper comprehension of the biology of presynaptic terminals as well as of Aβ-driven early synaptic defects occurring in prodromal stage of AD. Moreover, a better understating of Aβ involvement in cellular signal pathways may allow to set up more effective therapeutic interventions by detecting relevant molecular mechanisms, whose imbalance might ultimately lead to synaptic impairment in AD.
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Affiliation(s)
- Francesca Fagiani
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Italy.,Scuola Universitaria Superiore IUSS, Pavia, Italy
| | - Cristina Lanni
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Italy
| | - Marco Racchi
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Italy
| | - Alessia Pascale
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Italy
| | - Stefano Govoni
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Italy
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9
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Farr SA, Roesler E, Niehoff ML, Roby DA, McKee A, Morley JE. Metformin Improves Learning and Memory in the SAMP8 Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2020; 68:1699-1710. [PMID: 30958364 DOI: 10.3233/jad-181240] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Metformin is used for the treatment of insulin resistant diabetes. Diabetics are at an increased risk of developing dementia. Recent epidemiological studies suggest that metformin treatment prevents cognitive decline in diabetics. A pilot clinical study found cognitive improvement with metformin in patients with mild cognitive impairment (MCI). Preclinical studies suggest metformin reduces Alzheimer-like pathology in mouse models of Alzheimer's disease (AD). In the current study, we used 11-month-old SAMP8 mice. Mice were given daily injections of metformin at 20 mg/kg/sc or 200 mg/kg/sc for eight weeks. After four weeks, mice were tested in T-maze footshock avoidance, object recognition, and Barnes maze. At the end of the study, brain tissue was collected for analysis of PKC (PKCζ, PKCι, PKCα, PKCγ, PKCɛ), GSK-3β, pGSK-3βser9, pGSK-3βtyr216, pTau404, and APP. Metformin improved both acquisition and retention in SAMP8 mice in T-maze footshock avoidance, retention in novel object recognition, and acquisition in the Barnes maze. Biochemical analysis indicated that metformin increased both atypical and conventional forms of PKC; PKCζ, and PKCα at 20 mg/kg. Metformin significantly increased pGSK-3βser9 at 200 mg/kg, and decreased Aβ at 20 mg/kg and pTau404 and APPc99 at both 20 mg/kg and 200 mg/kg. There were no differences in blood glucose levels between the aged vehicle and metformin treated mice. Metformin improved learning and memory in the SAMP8 mouse model of spontaneous onset AD. Biochemical analysis indicates that metformin improved memory by decreasing APPc99 and pTau. The current study lends support to the therapeutic potential of metformin for AD.
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Affiliation(s)
- Susan A Farr
- Research and Development Service, VA Medical Center, MO, USA.,Division of Geriatric Medicine, Saint Louis University School of Medicine, MO, USA
| | - Elizabeth Roesler
- Division of Geriatric Medicine, Saint Louis University School of Medicine, MO, USA
| | - Michael L Niehoff
- Division of Geriatric Medicine, Saint Louis University School of Medicine, MO, USA
| | - Deborah A Roby
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, MO, USA
| | - Alexis McKee
- Division of Endocrinology, Diabetes, and Metabolism, Saint Louis University, MO, USA
| | - John E Morley
- Division of Geriatric Medicine, Saint Louis University School of Medicine, MO, USA
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10
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Harris M, El Hindy M, Usmari-Moraes M, Hudd F, Shafei M, Dong M, Hezwani M, Clark P, House M, Forshaw T, Kehoe P, Conway ME. BCAT-induced autophagy regulates Aβ load through an interdependence of redox state and PKC phosphorylation-implications in Alzheimer's disease. Free Radic Biol Med 2020; 152:755-766. [PMID: 31982508 DOI: 10.1016/j.freeradbiomed.2020.01.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/16/2020] [Accepted: 01/16/2020] [Indexed: 01/09/2023]
Abstract
Leucine, nutrient signal and substrate for the branched chain aminotransferase (BCAT) activates the mechanistic target of rapamycin (mTORC1) and regulates autophagic flux, mechanisms implicated in the pathogenesis of neurodegenerative conditions such as Alzheimer's disease (AD). BCAT is upregulated in AD, where a moonlighting role, imparted through its redox-active CXXC motif, has been suggested. Here we demonstrate that the redox state of BCAT signals differential phosphorylation by protein kinase C (PKC) regulating the trafficking of cellular pools of BCAT. We show inter-dependence of BCAT expression and proteins associated with the P13K/Akt/mTORC1 and autophagy signalling pathways. In response to insulin or an increase in ROS, BCATc is trafficked to the membrane and docks via palmitoylation, which is associated with BCATc-induced autophagy through PKC phosphorylation. In response to increased levels of BCATc, as observed in AD, amyloid β (Aβ) levels accumulate due to a shift in autophagic flux. This effect was diminished when incubated with leucine, indicating that dietary levels of amino acids show promise in regulating Aβ load. Together these findings show that increased BCATc expression, reported in human AD brain, will affect autophagy and Aβ load through the interdependence of its redox-regulated phosphorylation offering a novel target to address AD pathology.
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Affiliation(s)
- M Harris
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbor Lane, Bristol, BS16 1QY, UK
| | - M El Hindy
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbor Lane, Bristol, BS16 1QY, UK
| | - M Usmari-Moraes
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbor Lane, Bristol, BS16 1QY, UK
| | - F Hudd
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbor Lane, Bristol, BS16 1QY, UK
| | - M Shafei
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbor Lane, Bristol, BS16 1QY, UK
| | - M Dong
- Department of Chemistry, North Carolina Agricultural and Technical State University, Market Street, Greensboro, NC, 27411, USA
| | - M Hezwani
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbor Lane, Bristol, BS16 1QY, UK
| | - P Clark
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbor Lane, Bristol, BS16 1QY, UK
| | - M House
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbor Lane, Bristol, BS16 1QY, UK
| | - T Forshaw
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbor Lane, Bristol, BS16 1QY, UK
| | - P Kehoe
- Institute of Clinical Neurosciences, Learning and Research Building, Southmead Hospital, Bristol, United Kingdom
| | - M E Conway
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbor Lane, Bristol, BS16 1QY, UK.
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11
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He W, Tu M, Du Y, Li J, Pang Y, Dong Z. Nicotine Promotes AβPP Nonamyloidogenic Processing via RACK1-Dependent Activation of PKC in SH-SY5Y-AβPP695 Cells. J Alzheimers Dis 2020; 75:451-460. [PMID: 32250310 DOI: 10.3233/jad-200003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Accumulation of amyloid-β (Aβ) peptides, generated from amyloid-β precursor protein (AβPP) amyloidogenic processing, is one of the most salient disease hallmarks of Alzheimer's disease (AD). Nicotine is able to promote α-secretase-mediated AβPP nonamyloidogenic processing and increase the release of sAβPPα and C-terminal fragment of 83 amino acids (C83). However, the potential molecular mechanism remains elusive. OBJECTIVE The aim of the present study was to investigate the effect of nicotine on AβPP processing in SH-SY5Y cells that stably express human Swedish mutant AβPP695 (SH-SY5Y-AβPP695). METHODS The expression of AβPP and its C-terminal fragments including C99, C89, and C83, was measured in SH-SY5Y-AβPP695 cells treated with nicotine for 6 h. Protein kinase C (PKC) antagonist Ro30-8220 or agonist PMA was used to determine the role of PKC in AβPP processing. Lentivirus-mediated shRNA targeting receptor for activated C-kinase 1 (RACK1) gene was added into the media to knockdown RACK1 expression, and then AβPP processing was examined. RESULTS The results showed that 6 h of nicotine exposure increased the expression of α-secretase (ADAM10) and C83 in a dose dependent manner. While the β-secretase (BACE1), AβPP amyloidogenic processing products C89 and C99 as well as Aβ peptides (including Aβ40 and Aβ42) remained unchanged. We also found that nicotine elevated the expression of phosphorylated PKC (P-PKC) and RACK1 on the cytomembrane. PKC antagonist Ro30-8220 treatment prevented the increase of ADAM10 and C83 by nicotine. Genetic knockdown RACK1 significantly inhibited P-PKC, and consequently abolished the increase of ADAM10 and C83 by nicotine. CONCLUSION Taken together, these results indicate that nicotine effectively promotes AβPP nonamyloidogenic processing via RACK1-dependent activation of PKC in SH-SY5Y-AβPP695 cells and could be a potential molecule for AD treatment.
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Affiliation(s)
- Wenting He
- Pediatric Research Institute, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,National Clinical Research Center for Child Health and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Man Tu
- Pediatric Research Institute, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,National Clinical Research Center for Child Health and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Yehong Du
- Pediatric Research Institute, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,National Clinical Research Center for Child Health and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Junjie Li
- Pediatric Research Institute, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,National Clinical Research Center for Child Health and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Yayan Pang
- Pediatric Research Institute, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,National Clinical Research Center for Child Health and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Zhifang Dong
- Pediatric Research Institute, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,National Clinical Research Center for Child Health and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China
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12
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Strac DS, Konjevod M, Perkovic MN, Tudor L, Erjavec GN, Pivac N. Dehydroepiandrosterone (DHEA) and its Sulphate (DHEAS) in Alzheimer's Disease. Curr Alzheimer Res 2020; 17:141-157. [PMID: 32183671 DOI: 10.2174/1567205017666200317092310] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/20/2020] [Accepted: 01/26/2020] [Indexed: 01/01/2023]
Abstract
BACKGROUND Neurosteroids Dehydroepiandrosterone (DHEA) and Dehydroepiandrosterone Sulphate (DHEAS) are involved in many important brain functions, including neuronal plasticity and survival, cognition and behavior, demonstrating preventive and therapeutic potential in different neuropsychiatric and neurodegenerative disorders, including Alzheimer's disease. OBJECTIVE The aim of the article was to provide a comprehensive overview of the literature on the involvement of DHEA and DHEAS in Alzheimer's disease. METHODS PubMed and MEDLINE databases were searched for relevant literature. The articles were selected considering their titles and abstracts. In the selected full texts, lists of references were searched manually for additional articles. RESULTS We performed a systematic review of the studies investigating the role of DHEA and DHEAS in various in vitro and animal models, as well as in patients with Alzheimer's disease, and provided a comprehensive discussion on their potential preventive and therapeutic applications. CONCLUSION Despite mixed results, the findings of various preclinical studies are generally supportive of the involvement of DHEA and DHEAS in the pathophysiology of Alzheimer's disease, showing some promise for potential benefits of these neurosteroids in the prevention and treatment. However, so far small clinical trials brought little evidence to support their therapy in AD. Therefore, large-scale human studies are needed to elucidate the specific effects of DHEA and DHEAS and their mechanisms of action, prior to their applications in clinical practice.
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Affiliation(s)
- Dubravka S Strac
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Marcela Konjevod
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Matea N Perkovic
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Lucija Tudor
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Gordana N Erjavec
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
| | - Nela Pivac
- Laboratory for Molecular Neuropsychiatry, Division of Molecular Medicine, Rudjer Boskovic Institute, Zagreb, Croatia
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13
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Pastore D, Pacifici F, Dave KR, Palmirotta R, Bellia A, Pasquantonio G, Guadagni F, Donadel G, Di Daniele N, Abete P, Lauro D, Rundek T, Perez-Pinzon MA, Della-Morte D. Age-Dependent Levels of Protein Kinase Cs in Brain: Reduction of Endogenous Mechanisms of Neuroprotection. Int J Mol Sci 2019; 20:E3544. [PMID: 31331067 PMCID: PMC6678180 DOI: 10.3390/ijms20143544] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/15/2019] [Accepted: 07/17/2019] [Indexed: 02/07/2023] Open
Abstract
Neurodegenerative diseases are among the leading causes of mortality and disability worldwide. However, current therapeutic approaches have failed to reach significant results in their prevention and cure. Protein Kinase Cs (PKCs) are kinases involved in the pathophysiology of neurodegenerative diseases, such as Alzheimer's Disease (AD) and cerebral ischemia. Specifically ε, δ, and γPKC are associated with the endogenous mechanism of protection referred to as ischemic preconditioning (IPC). Existing modulators of PKCs, in particular of εPKC, such as ψεReceptor for Activated C-Kinase (ψεRACK) and Resveratrol, have been proposed as a potential therapeutic strategy for cerebrovascular and cognitive diseases. PKCs change in expression during aging, which likely suggests their association with IPC-induced reduction against ischemia and increase of neuronal loss occurring in senescent brain. This review describes the link between PKCs and cerebrovascular and cognitive disorders, and proposes PKCs modulators as innovative candidates for their treatment. We report original data showing εPKC reduction in levels and activity in the hippocampus of old compared to young rats and a reduction in the levels of δPKC and γPKC in old hippocampus, without a change in their activity. These data, integrated with other findings discussed in this review, demonstrate that PKCs modulators may have potential to restore age-related reduction of endogenous mechanisms of protection against neurodegeneration.
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Affiliation(s)
- Donatella Pastore
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Francesca Pacifici
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Kunjan R Dave
- Department of Neurology, The Evelyn McKnight Brain Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Raffaele Palmirotta
- Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro", 70124 Bari, Italy
| | - Alfonso Bellia
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
- Policlinico Tor Vergata Foundation, University Hospital, 00133 Rome, Italy
| | - Guido Pasquantonio
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Fiorella Guadagni
- Department of Human Sciences and Quality of Life Promotion, San Raffaele Roma Open University, 00166 Rome, Italy
| | - Giulia Donadel
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Nicola Di Daniele
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
- Policlinico Tor Vergata Foundation, University Hospital, 00133 Rome, Italy
| | - Pasquale Abete
- Department of Translational Medical Sciences, University of Naples, Federico II, 80138 Naples, Italy
| | - Davide Lauro
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
- Policlinico Tor Vergata Foundation, University Hospital, 00133 Rome, Italy
| | - Tatjana Rundek
- Department of Neurology, The Evelyn McKnight Brain Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Miguel A Perez-Pinzon
- Department of Neurology, The Evelyn McKnight Brain Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - David Della-Morte
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy.
- Department of Neurology, The Evelyn McKnight Brain Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
- Department of Human Sciences and Quality of Life Promotion, San Raffaele Roma Open University, 00166 Rome, Italy.
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14
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Bartolotti N, Lazarov O. CREB signals as PBMC-based biomarkers of cognitive dysfunction: A novel perspective of the brain-immune axis. Brain Behav Immun 2019; 78:9-20. [PMID: 30641141 PMCID: PMC6488430 DOI: 10.1016/j.bbi.2019.01.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/21/2018] [Accepted: 01/10/2019] [Indexed: 12/26/2022] Open
Abstract
To date, there is no reliable biomarker for the assessment or determination of cognitive dysfunction in Alzheimer's disease and related dementia. Such a biomarker would not only aid in diagnostics, but could also serve as a measure of therapeutic efficacy. It is widely acknowledged that the hallmarks of Alzheimer's disease, namely, amyloid deposits and neurofibrillary tangles, as well as their precursors and metabolites, are poorly correlated with cognitive function and disease stage and thus have low diagnostic or prognostic value. A lack of biomarkers is one of the major roadblocks in diagnosing the disease and in assessing the efficacy of potential therapies. The phosphorylation of cAMP Response Element Binding protein (pCREB) plays a major role in memory acquisition and consolidation. In the brain, CREB activation by phosphorylation at Ser133 and the recruitment of transcription cofactors such as CREB binding protein (CBP) is a critical step for the formation of memory. This set of processes is a prerequisite for the transcription of genes thought to be important for synaptic plasticity, such as Egr-1. Interestingly, recent work suggests that the expression of pCREB in peripheral blood mononuclear cells (PBMC) positively correlates with pCREB expression in the postmortem brain of Alzheimer's patients, suggesting not only that pCREB expression in PBMC might serve as a biomarker of cognitive dysfunction, but also that the dysfunction of CREB signaling may not be limited to the brain in AD, and that a link may exist between the regulation of CREB in the blood and in the brain. In this review we consider the evidence suggesting a correlation between the level of CREB signals in the brain and blood, the current knowledge about CREB in PBMC and its association with CREB in the brain, and the implications and mechanisms for a neuro-immune cross talk that may underlie this communication. This Review will discuss the possibility that peripheral dysregulation of CREB is an early event in AD pathogenesis, perhaps as a facet of immune system dysfunction, and that this impairment in peripheral CREB signaling modifies CREB signaling in the brain, thus exacerbating cognitive decline in AD. A more thorough understanding of systemic dysregulation of CREB in AD will facilitate the search for a biomarker of cognitive function in AD, and also aid in the understanding of the mechanisms underlying cognitive decline in AD.
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Affiliation(s)
- Nancy Bartolotti
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Orly Lazarov
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA.
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15
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The Role of Cysteine String Protein α Phosphorylation at Serine 10 and 34 by Protein Kinase Cγ for Presynaptic Maintenance. J Neurosci 2017; 38:278-290. [PMID: 29167402 DOI: 10.1523/jneurosci.1649-17.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 10/23/2017] [Accepted: 11/12/2017] [Indexed: 01/05/2023] Open
Abstract
Protein kinase Cγ (PKCγ) knock-out (KO) animals exhibit symptoms of Parkinson's disease (PD), including dopaminergic neuronal loss in the substantia nigra. However, the PKCγ substrates responsible for the survival of dopaminergic neurons in vivo have not yet been elucidated. Previously, we found 10 potent substrates in the striatum of PKCγ-KO mice. Here, we focused on cysteine string protein α (CSPα), a protein from the heat shock protein (HSP) 40 cochaperone families localized on synaptic vesicles. We found that in cultured cells, PKCγ phosphorylates CSPα at serine (Ser) 10 and Ser34. Additionally, apoptosis was found to have been enhanced by the overexpression of a phosphorylation-null mutant of CSPα, CSPα(S10A/S34A). Compared with wild-type (WT) CSPα, the CSPα(S10A/S34A) mutant had a weaker interaction with HSP70. However, in sharp contrast, a phosphomimetic CSPα(S10D/S34D) mutant, compared with WT CSPα, had a stronger interaction with HSP70. In addition, total levels of synaptosomal-associated protein (SNAP) 25, a main downstream target of the HSC70/HSP70 chaperone complex, were found to have decreased by the CSPα(S10A/S34A) mutant through increased ubiquitination of SNAP25 in PC12 cells. In the striatum of 2-year-old male PKCγ-KO mice, decreased phosphorylation levels of CSPα and decreased SNAP25 protein levels were observed. These findings indicate the phosphorylation of CSPα by PKCγ may protect the presynaptic terminal from neurodegeneration. The PKCγ-CSPα-HSC70/HSP70-SNAP25 axis, because of its role in protecting the presynaptic terminal, may provide a new therapeutic target for the treatment of PD.SIGNIFICANCE STATEMENT Cysteine string protein α (CSPα) is a protein belonging to the heat shock protein (HSP) 40 cochaperone families localized on synaptic vesicles, which maintain the presynaptic terminal. However, the function of CSPα phosphorylation by protein kinase C (PKC) for neuronal cell survival remains unclear. The experiments presented here demonstrate that PKCγ phosphorylates CSPα at serine (Ser) 10 and Ser34. CSPα phosphorylation at Ser10 and Ser34 by PKCγ protects the presynaptic terminal by promoting HSP70 chaperone activity. This report suggests that CSPα phosphorylation, because of its role in modulating HSP70 chaperone activity, may be a target for the treatment of neurodegeneration.
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16
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Racchi M, Buoso E, Ronfani M, Serafini MM, Galasso M, Lanni C, Corsini E. Role of Hormones in the Regulation of RACK1 Expression as a Signaling Checkpoint in Immunosenescence. Int J Mol Sci 2017; 18:ijms18071453. [PMID: 28684670 PMCID: PMC5535944 DOI: 10.3390/ijms18071453] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/22/2017] [Accepted: 06/30/2017] [Indexed: 02/07/2023] Open
Abstract
Immunosenescence defines the decline in immune function that occurs with aging. This has been associated, at least in part, with defective cellular signaling via protein kinase C (PKC) signal transduction pathways. Our data suggest reduced PKC activation and consequently reduced response to lipopolysaccharide (LPS) stimulation and cytokine release. The lack of PKC activation seems to be dependent on the reduced expression of the receptor for activated C kinase 1 (RACK1), a scaffolding protein involved in multiple signal transduction cascades. The defective expression of RACK1 may be dependent on age-related alteration of the balance between the adrenal hormones cortisol and dehydroepiandrosterone (DHEA). DHEA levels reduce with aging, while cortisol levels remain substantially unchanged, resulting in an overall increase in the cortisol:DHEA ratio. These hormonal changes are significant in the context of RACK1 expression and signaling function because DHEA administration in vivo and in vitro can restore the levels of RACK1 and the function of the PKC signaling cascade in aged animals and in human cells. In contrast, there is evidence that cortisol can act as a negative transcriptional regulator of RACK1 expression. The rack1 gene promoter contains a glucocorticoid responsive element that is also involved in androgen signaling. Furthermore DHEA may have an indirect influence on the post-transcriptional regulation of the functions of the glucocorticoid receptor. In this review, we will examine the role of the hormonal regulation of rack1 gene transcriptional regulation and the consequences on signaling and function in immune cells and immunosenescence.
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Affiliation(s)
- Marco Racchi
- Department of Drug Sciences, Università degli Studi di Pavia, Viale Taramelli 12/14, 27100 Pavia, Italy.
| | - Erica Buoso
- Department of Drug Sciences, Università degli Studi di Pavia, Viale Taramelli 12/14, 27100 Pavia, Italy.
| | - Melania Ronfani
- Department of Drug Sciences, Università degli Studi di Pavia, Viale Taramelli 12/14, 27100 Pavia, Italy.
| | - Melania M Serafini
- Department of Drug Sciences, Università degli Studi di Pavia, Viale Taramelli 12/14, 27100 Pavia, Italy.
- Scuola Universitaria Superiore IUSS Pavia, Piazza della Vittoria 15, 27100 Pavia, Italy.
| | - Marilisa Galasso
- Department of Drug Sciences, Università degli Studi di Pavia, Viale Taramelli 12/14, 27100 Pavia, Italy.
| | - Cristina Lanni
- Department of Drug Sciences, Università degli Studi di Pavia, Viale Taramelli 12/14, 27100 Pavia, Italy.
| | - Emanuela Corsini
- Laboratory of Toxicology, Department of Environmental Science and Policy, Università degli Studi di Milano, Via Balzaretti 9, 20133 Milano, Italy.
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17
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Transcriptional regulation of RACK1 and modulation of its expression: Role of steroid hormones and significance in health and aging. Cell Signal 2017; 35:264-271. [DOI: 10.1016/j.cellsig.2017.02.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 02/07/2017] [Accepted: 02/08/2017] [Indexed: 12/27/2022]
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18
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Abstract
Receptor for activated C kinase 1 (RACK1) is an evolutionarily conserved scaffolding protein within the tryptophan-aspartate (WD) repeat family of proteins. RACK1 can bind multiple signaling molecules concurrently, as well as stabilize and anchor proteins. RACK1 also plays an important role at focal adhesions, where it acts to regulate cell migration. In addition, RACK1 is a ribosomal binding protein and thus, regulates translation. Despite these numerous functions, little is known about how RACK1 regulates nervous system development. Here, we review three studies that examine the role of RACK1 in neural development. In brief, these papers demonstrate that (1) RACK-1, the C. elegans homolog of mammalian RACK1, is required for axon guidance; (2) RACK1 is required for neurite extension of neuronally differentiated rat PC12 cells; and (3) RACK1 is required for axon outgrowth of primary mouse cortical neurons. Thus, it is evident that RACK1 is critical for appropriate neural development in a wide range of species, and future discoveries could reveal whether RACK1 and its signaling partners are potential targets for treatment of neurodevelopmental disorders or a therapeutic approach for axonal regeneration.
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Affiliation(s)
- Leah Kershner
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Kristy Welshhans
- Department of Biological Sciences, Kent State University, Kent, OH, USA.,School of Biomedical Sciences, Kent State University, Kent, OH, USA
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19
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Coronas-Samano G, Baker KL, Tan WJT, Ivanova AV, Verhagen JV. Fus1 KO Mouse As a Model of Oxidative Stress-Mediated Sporadic Alzheimer's Disease: Circadian Disruption and Long-Term Spatial and Olfactory Memory Impairments. Front Aging Neurosci 2016; 8:268. [PMID: 27895577 PMCID: PMC5108791 DOI: 10.3389/fnagi.2016.00268] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 10/24/2016] [Indexed: 12/13/2022] Open
Abstract
Insufficient advances in the development of effective therapeutic treatments of sporadic Alzheimer's Disease (sAD) to date are largely due to the lack of sAD-relevant animal models. While the vast majority of models do recapitulate AD's hallmarks of plaques and tangles by virtue of tau and/or beta amyloid overexpression, these models do not reflect the fact that in sAD (unlike familial AD) these genes are not risk factors per se and that other mechanisms like oxidative stress, metabolic dysregulation and inflammation play key roles in AD etiology. Here we characterize and propose the Fus1 KO mice that lack a mitochondrial protein Fus1/Tusc2 as a new sAD model. To establish sAD relevance, we assessed sAD related deficits in Fus1 KO and WT adult mice of 4-5 months old, the equivalent human age when the earliest cognitive and olfactory sAD symptoms arise. Fus1 KO mice showed oxidative stress (increased levels of ROS, decreased levels of PRDX1), disruption of metabolic homeostasis (decreased levels of ACC2, increased phosphorylation of AMPK), autophagy (decreased levels of LC3-II), PKC (decreased levels of RACK1) and calcium signaling (decreased levels of Calb2) in the olfactory bulb and/or hippocampus. Mice were behaviorally tested using objective and accurate video tracking (Noldus), in which Fus1 KO mice showed clear deficits in olfactory memory (decreased habituation/cross-habituation in the short and long term), olfactory guided navigation memory (inability to reduce their latency to find the hidden cookie), spatial memory (learning impairments on finding the platform in the Morris water maze) and showed more sleep time during the diurnal cycle. Fus1 KO mice did not show clear deficits in olfactory perception (cross-habituation), association memory (passive avoidance) or in species-typical behavior (nest building) and no increased anxiety (open field, light-dark box) or depression/anhedonia (sucrose preference) at this relatively young age. These neurobehavioral deficits of the Fus1 KO mice at this relatively young age are highly relevant to sAD, making them suitable for effective research on pharmacological targets in the context of early intervention of sAD.
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Affiliation(s)
| | - Keeley L Baker
- The John B. Pierce LaboratoryNew Haven, CT, USA; Department of Neuroscience, Yale University School of MedicineNew Haven, CT, USA
| | - Winston J T Tan
- Department of Surgery, Yale University School of Medicine New Haven, CT, USA
| | - Alla V Ivanova
- Department of Surgery, Yale University School of Medicine New Haven, CT, USA
| | - Justus V Verhagen
- The John B. Pierce LaboratoryNew Haven, CT, USA; Department of Neuroscience, Yale University School of MedicineNew Haven, CT, USA
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Suliman NA, Mat Taib CN, Mohd Moklas MA, Adenan MI, Hidayat Baharuldin MT, Basir R. Establishing Natural Nootropics: Recent Molecular Enhancement Influenced by Natural Nootropic. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2016; 2016:4391375. [PMID: 27656235 PMCID: PMC5021479 DOI: 10.1155/2016/4391375] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 07/18/2016] [Indexed: 01/24/2023]
Abstract
Nootropics or smart drugs are well-known compounds or supplements that enhance the cognitive performance. They work by increasing the mental function such as memory, creativity, motivation, and attention. Recent researches were focused on establishing a new potential nootropic derived from synthetic and natural products. The influence of nootropic in the brain has been studied widely. The nootropic affects the brain performances through number of mechanisms or pathways, for example, dopaminergic pathway. Previous researches have reported the influence of nootropics on treating memory disorders, such as Alzheimer's, Parkinson's, and Huntington's diseases. Those disorders are observed to impair the same pathways of the nootropics. Thus, recent established nootropics are designed sensitively and effectively towards the pathways. Natural nootropics such as Ginkgo biloba have been widely studied to support the beneficial effects of the compounds. Present review is concentrated on the main pathways, namely, dopaminergic and cholinergic system, and the involvement of amyloid precursor protein and secondary messenger in improving the cognitive performance.
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Affiliation(s)
- Noor Azuin Suliman
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Malaysia
| | - Che Norma Mat Taib
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Malaysia
| | - Mohamad Aris Mohd Moklas
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Malaysia
| | - Mohd Ilham Adenan
- Atta-ur-Rahman Institute for Natural Product Discovery, Aras 9 Bangunan FF3, UiTM Puncak Alam, Bandar Baru Puncak Alam, 42300 Selangor Darul Ehsan, Malaysia
| | | | - Rusliza Basir
- Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Malaysia
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Talman V, Pascale A, Jäntti M, Amadio M, Tuominen RK. Protein Kinase C Activation as a Potential Therapeutic Strategy in Alzheimer's Disease: Is there a Role for Embryonic Lethal Abnormal Vision-like Proteins? Basic Clin Pharmacol Toxicol 2016; 119:149-60. [PMID: 27001133 DOI: 10.1111/bcpt.12581] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 03/04/2016] [Indexed: 12/28/2022]
Abstract
Alzheimer's disease (AD), the most common cause of dementia, is an irreversible and progressive neurodegenerative disorder. It affects predominantly brain areas that are critical for memory and learning and is characterized by two main pathological hallmarks: extracellular amyloid plaques and intracellular neurofibrillary tangles. Protein kinase C (PKC) has been classified as one of the cognitive kinases controlling memory and learning. By regulating several signalling pathways involved in amyloid and tau pathologies, it also plays an inhibitory role in AD pathophysiology. Among downstream targets of PKC are the embryonic lethal abnormal vision (ELAV)-like RNA-binding proteins that modulate the stability and the translation of specific target mRNAs involved in synaptic remodelling linked to cognitive processes. This MiniReview summarizes the current evidence on the role of PKC and ELAV-like proteins in learning and memory, highlighting how their derangement can contribute to AD pathophysiology. This last aspect emphasizes the potential of pharmacological activation of PKC as a promising therapeutic strategy for the treatment of AD.
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Affiliation(s)
- Virpi Talman
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Alessia Pascale
- Section of Pharmacology, Department of Drug Sciences, University of Pavia, Pavia, Italy
| | - Maria Jäntti
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Marialaura Amadio
- Section of Pharmacology, Department of Drug Sciences, University of Pavia, Pavia, Italy
| | - Raimo K Tuominen
- Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
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22
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Deficit of RACK1 contributes to the spatial memory impairment via upregulating BECLIN1 to induce autophagy. Life Sci 2016; 151:115-121. [PMID: 26930371 DOI: 10.1016/j.lfs.2016.02.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 12/14/2015] [Accepted: 02/05/2016] [Indexed: 11/21/2022]
Abstract
AIMS Deficiency of activated C kinase1 (RACK1) in the brain of aging animal and Alzheimer's disease was characterized by cognitive dementia and spatial memory impairment. However, the correlation between the RACK1 and spatial memory impairment and the mechanism involved in it remains unknown. MAIN METHODS Spatial memory impairment was performed in mice by lateral ventricle injection of Aβ25-35 (n=16, 10μl) and intraperitoneal injection of scopolamine (n=16, 10ml/kg). After the Morris water maze (MWM) which was performed to determine the ability of learning and memory in mice, expression of RACK1 was tested and the damage of hippocampus was confirmed by histopathology test. ShRACK1 was then used to decrease the level of RACK1 in hippocampus to test the ability of learning and memory and histopathology changes in hippocampus. To look into the mechanism of RACK1 on spatial memory impairment, we further measured the expression of autophagy proteins BECLIN1 and LC3-II/I in hippocampus of all mice. KEY FINDINGS Both the Aβ25-35, scopolamine impaired the spatial memory in mice (for escape latency, P=0.0004, P<0.0001) and severely damaged hippocampal DG neurons (P=0.012, P=0.014). The expression of RACK1 was significantly decreased which was concomitant with elevated BECLIN1 and LC3-II/I (P<0.001). Suppression of RACK1 by ShRACK1 plasmid (shGnb2l1) significantly impaired the spatial memory in mice, damaged hippocampal DG neurons (P=0.013), and increased the proteins of BECLIN1 and LC3-II/I (P<0.005). SIGNIFICANCE It demonstrated that the deficit of RACK1 in hippocampus impairs the ability of learning and memory in mice via up regulating autophagy.
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Abstract
Precise control of the amplitude of protein kinase C (PKC) signalling is essential for cellular homoeostasis, and disruption of this control leads to pathophysiological states such as cancer, neurodegeneration and diabetes. For conventional and novel PKC, this amplitude is meticulously tuned by multiple inputs that regulate the amount of enzyme in the cell, its ability to sense its allosteric activator diacylglycerol, and protein scaffolds that co-ordinate access to substrates. Key to regulation of the signalling output of most PKC isoenzymes is the ability of cytosolic enzyme to respond to the membrane-embedded lipid second messenger, diacylglycerol, in a dynamic range that prevents signalling in the absence of agonists but allows efficient activation in response to small changes in diacylglycerol levels. The present review discusses the regulatory inputs that control the spatiotemporal dynamics of PKC signalling, with a focus on conventional and novel PKC isoenzymes.
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Lucke-Wold BP, Turner RC, Logsdon AF, Simpkins JW, Alkon DL, Smith KE, Chen YW, Tan Z, Huber JD, Rosen CL. Common mechanisms of Alzheimer's disease and ischemic stroke: the role of protein kinase C in the progression of age-related neurodegeneration. J Alzheimers Dis 2015; 43:711-24. [PMID: 25114088 PMCID: PMC4446718 DOI: 10.3233/jad-141422] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Ischemic stroke and Alzheimer's disease (AD), despite being distinct disease entities, share numerous pathophysiological mechanisms such as those mediated by inflammation, immune exhaustion, and neurovascular unit compromise. An important shared mechanistic link is acute and chronic changes in protein kinase C (PKC) activity. PKC isoforms have widespread functions important for memory, blood-brain barrier maintenance, and injury repair that change as the body ages. Disease states accelerate PKC functional modifications. Mutated forms of PKC can contribute to neurodegeneration and cognitive decline. In some cases the PKC isoforms are still functional but are not successfully translocated to appropriate locations within the cell. The deficits in proper PKC translocation worsen stroke outcome and amyloid-β toxicity. Cross talk between the innate immune system and PKC pathways contribute to the vascular status within the aging brain. Unfortunately, comorbidities such as diabetes, obesity, and hypertension disrupt normal communication between the two systems. The focus of this review is to highlight what is known about PKC function, how isoforms of PKC change with age, and what additional alterations are consequences of stroke and AD. The goal is to highlight future therapeutic targets that can be applied to both the treatment and prevention of neurologic disease. Although the pathology of ischemic stroke and AD are different, the similarity in PKC responses warrants further investigation, especially as PKC-dependent events may serve as an important connection linking age-related brain injury.
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Affiliation(s)
- Brandon P. Lucke-Wold
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Ryan C. Turner
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Aric F. Logsdon
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, USA
| | - James W. Simpkins
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Daniel L. Alkon
- Blanchette Rockefeller Neurosciences Institute, Morgantown, WV, USA
| | - Kelly E. Smith
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, USA
| | - Yi-Wen Chen
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Zhenjun Tan
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Jason D. Huber
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, USA
| | - Charles L. Rosen
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
- Correspondence to: Charles L. Rosen, MD, PhD, Department of Neurosurgery, West Virginia University School of Medicine, One Medical Center Drive, Suite 4300, Health Sciences Center, PO Box 9183, Morgantown, WV 26506-9183, USA. Tel.: +1 304 293 5041; Fax: +1 304 293 4819;
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25
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Dong ZF, Tang LJ, Deng GF, Zeng T, Liu SJ, Wan RP, Liu T, Zhao QH, Yi YH, Liao WP, Long YS. Transcription of the human sodium channel SCN1A gene is repressed by a scaffolding protein RACK1. Mol Neurobiol 2014; 50:438-48. [PMID: 24436055 DOI: 10.1007/s12035-014-8633-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/02/2014] [Indexed: 11/29/2022]
Abstract
Voltage-gated sodium channel α subunit type I (Nav1.1, encoded by SCN1A gene) plays a critical role in the initiation of action potential in the central nervous system. Downregulated expression of SCN1A is believed to be associated with epilepsy. Here, we found that the SCN1A promoter (P1c), located at the 5' untranslated exon 1c, drove the reporter gene expression in human NT2 cells, and a region between nt +53 and +62 downstream of the P1c promoter repressed the promoter activity. Further analyses showed that a scaffolding protein RACK1 (receptor for activated C kinase 1) was involved in binding to this silencer. Knockdown of RACK1 expression in NT2 cells deprived the repressive role of the silencer on the P1c promoter and increased SCN1A transcription, suggesting the potential involvement of RACK1 in negatively regulating SCN1A transcription via interaction with the silencer. Furthermore, we demonstrated that the binding of the protein complex including RACK1 to the SCN1A promoter motif was decreased in neuron-like differentiation of the NT2 cells induced by retinoic acid and resulted in the upregulation of SCN1A transcription. Taken together, this study reports a novel role of RACK1 in regulating SCN1A expression that participates in retinoic acid-induced neuronal differentiation of NT2 cells.
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Affiliation(s)
- Zhao-Fei Dong
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changgang East Road, Guangzhou, 510260, China
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26
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Burk JA. Roles of cholinergic receptors during attentional modulation of cue detection. World J Pharmacol 2013; 2:84-91. [DOI: 10.5497/wjp.v2.i4.84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 08/17/2013] [Accepted: 09/13/2013] [Indexed: 02/06/2023] Open
Abstract
Basal forebrain corticopetal cholinergic neurons are known to be necessary for normal attentional processing. Alterations of cholinergic system functioning have been associated with several neuropsychiatric diseases, such as Alzheimer’s disease and schizophrenia, in which attentional dysfunction is thought to be a key contributing factor. Loss of cortical cholinergic inputs impairs performance in attention-demanding tasks. Moreover, measures of acetylcholine with microdialysis and, more recently, of choline with enzyme-coated microelectrodes have begun to elucidate the precise cognitive demands that activate the cholinergic system on distinct time scales. However, the receptor actions following acetylcholine release under attentionally-challenging conditions are only beginning to be understood. The present review is designed to summarize the evidence regarding the actions of acetylcholine at muscarinic and nicotinic receptors under cognitively challenging conditions in order to evaluate the functions mediated by these two different cholinergic receptor classes. Moreover, evidence that supports beneficial effects of muscarinic muscarinic-1 receptor agonists and selective nicotinic receptor subtype agonists for cognitive processing will be discussed. Finally, some challenges and limitations of targeting the cholinergic system for treating cognitive deficits along with future research directions will be mentioned. In conclusion, multiple aspects of cholinergic neurotransmission must be considered when attempting to restore function of this neuromodulatory system.
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27
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Perluigi M, Coccia R, Butterfield DA. 4-Hydroxy-2-nonenal, a reactive product of lipid peroxidation, and neurodegenerative diseases: a toxic combination illuminated by redox proteomics studies. Antioxid Redox Signal 2012; 17:1590-609. [PMID: 22114878 PMCID: PMC3449441 DOI: 10.1089/ars.2011.4406] [Citation(s) in RCA: 343] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 11/21/2011] [Accepted: 11/23/2011] [Indexed: 11/13/2022]
Abstract
SIGNIFICANCE Among different forms of oxidative stress, lipid peroxidation comprises the interaction of free radicals with polyunsaturated fatty acids, which in turn leads to the formation of highly reactive electrophilic aldehydes. Among these, the most abundant aldehydes are 4-hydroxy-2-nonenal (HNE) and malondialdehyde, while acrolein is the most reactive. HNE is considered a robust marker of oxidative stress and a toxic compound for several cell types. Proteins are particularly susceptible to modification caused by HNE, and adduct formation plays a critical role in multiple cellular processes. RECENT ADVANCES With the outstanding progress of proteomics, the identification of putative biomarkers for neurodegenerative disorders has been the main focus of several studies and will continue to be a difficult task. CRITICAL ISSUES The present review focuses on the role of lipid peroxidation, particularly of HNE-induced protein modification, in neurodegenerative diseases. By comparing results obtained in different neurodegenerative diseases, it may be possible to identify both similarities and specific differences in addition to better characterize selective neurodegenerative phenomena associated with protein dysfunction. Results obtained in our laboratory and others support the common deregulation of energy metabolism and mitochondrial function in neurodegeneration. FUTURE DIRECTIONS Research towards a better understanding of the molecular mechanisms involved in neurodegeneration together with identification of specific targets of oxidative damage is urgently required. Redox proteomics will contribute to broaden the knowledge in regard to potential biomarkers for disease diagnosis and may also provide insight into damaged metabolic networks and potential targets for modulation of disease progression.
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Affiliation(s)
- Marzia Perluigi
- Department of Biochemical Sciences, Faculty of Pharmacy and Medicine, Sapienza University of Rome, Rome, Italy.
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28
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Butterfield DA, Perluigi M, Reed T, Muharib T, Hughes CP, Robinson RAS, Sultana R. Redox proteomics in selected neurodegenerative disorders: from its infancy to future applications. Antioxid Redox Signal 2012; 17:1610-55. [PMID: 22115501 PMCID: PMC3448942 DOI: 10.1089/ars.2011.4109] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 11/21/2011] [Accepted: 11/23/2011] [Indexed: 12/12/2022]
Abstract
Several studies demonstrated that oxidative damage is a characteristic feature of many neurodegenerative diseases. The accumulation of oxidatively modified proteins may disrupt cellular functions by affecting protein expression, protein turnover, cell signaling, and induction of apoptosis and necrosis, suggesting that protein oxidation could have both physiological and pathological significance. For nearly two decades, our laboratory focused particular attention on studying oxidative damage of proteins and how their chemical modifications induced by reactive oxygen species/reactive nitrogen species correlate with pathology, biochemical alterations, and clinical presentations of Alzheimer's disease. This comprehensive article outlines basic knowledge of oxidative modification of proteins and lipids, followed by the principles of redox proteomics analysis, which also involve recent advances of mass spectrometry technology, and its application to selected age-related neurodegenerative diseases. Redox proteomics results obtained in different diseases and animal models thereof may provide new insights into the main mechanisms involved in the pathogenesis and progression of oxidative-stress-related neurodegenerative disorders. Redox proteomics can be considered a multifaceted approach that has the potential to provide insights into the molecular mechanisms of a disease, to find disease markers, as well as to identify potential targets for drug therapy. Considering the importance of a better understanding of the cause/effect of protein dysfunction in the pathogenesis and progression of neurodegenerative disorders, this article provides an overview of the intrinsic power of the redox proteomics approach together with the most significant results obtained by our laboratory and others during almost 10 years of research on neurodegenerative disorders since we initiated the field of redox proteomics.
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Affiliation(s)
- D Allan Butterfield
- Department of Chemistry, Center of Membrane Sciences, Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40506, USA.
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29
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Robinson AM, Mangini DF, Burk JA. Task demands dissociate the effects of muscarinic M1 receptor blockade and protein kinase C inhibition on attentional performance in rats. J Psychopharmacol 2012; 26:1143-50. [PMID: 21890584 PMCID: PMC3251644 DOI: 10.1177/0269881111415732] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The cholinergic system is known to be necessary for normal attentional processing. However, the receptors and mechanisms mediating the effects of acetylcholine on attention remain unclear. Previous work in our laboratory suggested that cholinergic muscarinic receptors are critical for maintaining performance in an attention-demanding task in rats. We examined the role of the muscarinic M(1) receptor and protein kinase C (PKC), which is activated by the M(1) receptor, in attention task performance. Rats were trained in an attention-demanding task requiring discrimination of brief (500, 100, 25 ms) visual signals from trials with no signal presentation. The effects of muscarinic M(1) receptor blockade were assessed by administering dicyclomine (0-5.0 mg/kg). The effects of PKC inhibition were assessed by administering chelerythrine chloride (0-2.0 mg/kg). Dicyclomine decreased the accuracy of detecting longer signals in this attention task, including when attentional demands were increased by flashing a houselight throughout the session. Chelerythrine chloride decreased the accuracy of signal detection in the standard version of the task but not when the houselight was flashed throughout the session. The present findings indicate that muscarinic M(1) receptors are critical for maintaining performance when attentional demands are increased, and that PKC activity may contribute to some aspects of attentional performance.
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Affiliation(s)
- Andrea M Robinson
- Department of Psychology, College of William and Mary, Williamsburg, VA, USA
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30
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Adams DR, Ron D, Kiely PA. RACK1, A multifaceted scaffolding protein: Structure and function. Cell Commun Signal 2011; 9:22. [PMID: 21978545 PMCID: PMC3195729 DOI: 10.1186/1478-811x-9-22] [Citation(s) in RCA: 324] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Accepted: 10/06/2011] [Indexed: 12/17/2022] Open
Abstract
The Receptor for Activated C Kinase 1 (RACK1) is a member of the tryptophan-aspartate repeat (WD-repeat) family of proteins and shares significant homology to the β subunit of G-proteins (Gβ). RACK1 adopts a seven-bladed β-propeller structure which facilitates protein binding. RACK1 has a significant role to play in shuttling proteins around the cell, anchoring proteins at particular locations and in stabilising protein activity. It interacts with the ribosomal machinery, with several cell surface receptors and with proteins in the nucleus. As a result, RACK1 is a key mediator of various pathways and contributes to numerous aspects of cellular function. Here, we discuss RACK1 gene and structure and its role in specific signaling pathways, and address how posttranslational modifications facilitate subcellular location and translocation of RACK1. This review condenses several recent studies suggesting a role for RACK1 in physiological processes such as development, cell migration, central nervous system (CN) function and circadian rhythm as well as reviewing the role of RACK1 in disease.
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Affiliation(s)
- David R Adams
- Department of Life Sciences, and Materials and Surface Science Institute, University of Limerick, Limerick, Ireland.
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Reed TT. Lipid peroxidation and neurodegenerative disease. Free Radic Biol Med 2011; 51:1302-19. [PMID: 21782935 DOI: 10.1016/j.freeradbiomed.2011.06.027] [Citation(s) in RCA: 442] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 06/17/2011] [Accepted: 06/22/2011] [Indexed: 11/27/2022]
Abstract
Lipid peroxidation is a complex process involving the interaction of oxygen-derived free radicals with polyunsaturated fatty acids, resulting in a variety of highly reactive electrophilic aldehydes. Since 1975, lipid peroxidation has been extensively studied in a variety of organisms. As neurodegenerative diseases became better understood, research establishing a link between this form of oxidative damage, neurodegeneration, and disease has provided a wealth of knowledge to the scientific community. With the advent of proteomics in 1995, the identification of biomarkers for neurodegenerative disorders became of paramount importance to better understand disease pathogenesis and develop potential therapeutic strategies. This review focuses on the relationship between lipid peroxidation and neurodegenerative diseases. It also demonstrates how findings in current research support the common themes of altered energy metabolism and mitochondrial dysfunction in neurodegenerative disorders.
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Affiliation(s)
- Tanea T Reed
- Department of Chemistry, Eastern Kentucky University, Richmond, KY 40475, USA.
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32
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Oxidative Stress and β-Amyloid Protein in Alzheimer’s Disease. Neuromolecular Med 2011; 13:223-50. [DOI: 10.1007/s12017-011-8155-9] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 08/26/2011] [Indexed: 12/21/2022]
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Butterfield DA, Reed T, Sultana R. Roles of 3-nitrotyrosine- and 4-hydroxynonenal-modified brain proteins in the progression and pathogenesis of Alzheimer's disease. Free Radic Res 2011; 45:59-72. [PMID: 20942567 DOI: 10.3109/10715762.2010.520014] [Citation(s) in RCA: 280] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Proteins play an important role in normal structure and function of the cells. Oxidative modification of proteins may greatly alter the structure and may subsequently lead to loss of normal physiological cell functions and may lead to abnormal function of cell and eventually to cell death. These modifications may be reversible or irreversible. Reversible protein modifications, such as phosphorylation, can be overcome by specific enzymes that cause a protein to 'revert' back to its original protein structure, while irreversible protein modifications cannot. Several important irreversible protein modifications include protein nitration and HNE modification, both which have been extensively investigated in research on the progression of Alzheimer's disease (AD). From the earliest stage of AD throughout the advancement of the disorder there is evidence of increased protein nitration and HNE modification. These protein modifications lead to decreased enzymatic activity, which correlates directly to protein efficacy and provides support for several common themes in AD pathology, namely altered energy metabolism, mitochondrial dysfunction and reduced cholinergic neurotransmission. The current review summarized some of the findings on protein oxidation related to different stages of Alzheimer's disease (AD) that will be helpful in understanding the role of protein oxidation in the progression and pathogenesis of AD.
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Affiliation(s)
- D Allan Butterfield
- Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055, USA.
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34
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Sun MK, Alkon DL. Protein kinase C activators as synaptogenic and memory therapeutics. Arch Pharm (Weinheim) 2010; 342:689-98. [PMID: 19899099 DOI: 10.1002/ardp.200900050] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The last decade has witnessed a rapid progress in understanding of the molecular cascades that may underlie memory and memory disorders. Among the critical players, activity of protein kinase C (PKC) isoforms is essential for many types of learning and memory and their dysfunction, and is critical in memory disorders. PKC inhibition and functional deficits lead to an impairment of various types of learning and memory, consistent with the observations that neurotoxic amyloid inhibits PKC activity and that transgenic animal models with PKCbeta deficit exhibit impaired capacity in cognition. In addition, PKC isozymes play a regulatory role in amyloid production and accumulation. Restoration of the impaired PKC signal pathway pharmacologically results in an enhanced memory capacity and synaptic remodeling / repair and synaptogenesis, and, therefore, represents a potentially important strategy for the treatment of memory disorders, including Alzheimer's dementia. The PKC activators, especially those that are isozyme-specific, are a new class of drug candidates that may be developed as future memory therapeutics.
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Affiliation(s)
- Miao-Kun Sun
- Blanchette Rockefeller Neurosciences Institute, Rockville, MD 20850, USA.
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35
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Yi H, Li XH, Yi B, Zheng J, Zhu G, Li C, Li MY, Zhang PF, Li JL, Chen ZC, Xiao ZQ. Identification of Rack1, EF-Tu and Rhodanese as Aging-Related Proteins in Human Colonic Epithelium by Proteomic Analysis. J Proteome Res 2010; 9:1416-23. [PMID: 20099848 DOI: 10.1021/pr9009386] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hong Yi
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Xin-Hui Li
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Bin Yi
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Jie Zheng
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Guo Zhu
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Cui Li
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Mao-Yu Li
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Peng-Fei Zhang
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Jian-Ling Li
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Zhu-Chu Chen
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Zhi-Qiang Xiao
- Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China
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36
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Liu W, Dou F, Feng J, Yan Z. RACK1 is involved in β-amyloid impairment of muscarinic regulation of GABAergic transmission. Neurobiol Aging 2009; 32:1818-26. [PMID: 19954860 DOI: 10.1016/j.neurobiolaging.2009.10.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 10/19/2009] [Accepted: 10/29/2009] [Indexed: 12/21/2022]
Abstract
RACK1 (receptor for activated C-kinase 1), an anchoring protein that shuttles activated PKC to cellular membranes, plays an important role in PKC-mediated signal transduction pathways. A significant loss of RACK1 has been found in the brain of aging animals and Alzheimer's disease (AD) patients, which implicates the potential involvement of RACK1 in altered PKC activation associated with dementia. Our previous studies have demonstrated that GABAergic inhibition in prefrontal cortex, which is important for cognitive processes like "working memory", is regulated by muscarinic receptors via a PKC-dependent mechanism, and this effect is impaired by β-amyloid peptide (Aβ). In this study, we found that Aβ oligomers decreased RACK1 distribution in the membrane fraction of cortical neurons. Moreover, overexpression of RACK1 rescued the effect of muscarinic receptors on GABAergic transmission in Aβ-treated cortical cultures in vitro and Aβ-injected cortical neurons in vivo. These results suggest that the Aβ-induced loss of RACK1 distribution in the cell membrane may underlie the Aβ impairment of muscarinic regulation of PKC and GABAergic transmission. Thus, RACK1 provides a potential therapeutic target that can restore some of the impaired cellular processes by Aβ.
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Affiliation(s)
- Wenhua Liu
- Department of Physiology and Biophysics, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY 14214, USA
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37
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Zhang GR, Liu M, Cao H, Kong L, Wang X, O'Brien JA, Wu SC, Cook RG, Geller AI. Improved spatial learning in aged rats by genetic activation of protein kinase C in small groups of hippocampal neurons. Hippocampus 2009; 19:413-23. [PMID: 18942114 PMCID: PMC2670945 DOI: 10.1002/hipo.20506] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Age-related decline in human cognition is well known, and there are correlative changes in the function of neocortical and hippocampal neurons. Similarly, age-related decline in learning has been observed in rodents, including deficits in a hippocampal-dependent learning paradigm, the Morris water maze. Furthermore, there are correlative deficits in specific signaling pathways, including protein kinase C (PKC) pathways, in cerebellar, hippocampal, or neocortical neurons. PKC pathways are strong candidates for mediating the molecular changes that underlie spatial learning, as they play critical roles in neurotransmitter release and synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD), and deletion of specific PKC genes results in deficits in learning. Conversely, genetic activation of PKC pathways in small groups of hippocampal or cortical neurons enhances learning in specific paradigms. In this study, the authors delivered a constitutively active PKC into small groups of hippocampal dentate granule neurons in aged rats (using a herpes simplex virus-1 vector). Aged 2-year-old rats that received the constitutively active PKC displayed improved performance in the Morris water maze relative to controls in three different measures. These results indicate that PKC pathways play an important role in mediating spatial learning in aged rats. Additionally, these results represent a system for studying the neural mechanisms underlying aging-related learning deficits, and potentially developing gene therapies for cognitive and age-related deficits.
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Affiliation(s)
- Guo-Rong Zhang
- Department of Neurology, West Roxbury VA Hospital/Harvard Medical School, West Roxbury, MA 02132, USA
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38
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Lam W, Chan WM, Lo TW, Wong AKY, Wu CC, Chan HYE. Human receptor for activated protein kinase C1 associates with polyglutamine aggregates and modulates polyglutamine toxicity. Biochem Biophys Res Commun 2008; 377:714-719. [PMID: 18948080 DOI: 10.1016/j.bbrc.2008.10.057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 10/10/2008] [Indexed: 11/26/2022]
Abstract
Formation of SDS-insoluble protein aggregates in affected neurons is a cellular pathological feature of polyglutamine (polyQ) disease. We identified a multi-WD-domain protein, receptor for activated protein kinase C1 (RACK1), as a novel polyQ aggregate component from a Drosophila transgenic polyQ disease model. We showed that WD domains were crucial determinants for the recruitment of RACK1 to polyQ aggregates. Over-expression of the human RACK1 protein suppressed polyQ-induced neurodegeneration in vivo. This is the first report to demonstrate the involvement of WD-domain proteins in polyQ pathogenesis, and the proteomic approach described here can be applied to the investigation of other protein aggregation disorders including Alzheimer's and Parkinson's diseases.
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Affiliation(s)
- Wun Lam
- Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Molecular Biotechnology Programme, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Wing Man Chan
- Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Molecular Biotechnology Programme, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Tsz Wai Lo
- Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Molecular Biotechnology Programme, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Azaria Kam Yan Wong
- Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Molecular Biotechnology Programme, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Chi Chung Wu
- Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Molecular Biotechnology Programme, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Ho Yin Edwin Chan
- Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Molecular Biotechnology Programme, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Department of Biochemistry (Science), The Chinese University of Hong Kong, Laboratory of Drosophila Research, Molecular Biotechnology Programme, Room 509B, Mong Man Wai Building, Shatin, N.T., Hong Kong SAR, China.
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39
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Reed T, Perluigi M, Sultana R, Pierce WM, Klein JB, Turner DM, Coccia R, Markesbery WR, Butterfield DA. Redox proteomic identification of 4-hydroxy-2-nonenal-modified brain proteins in amnestic mild cognitive impairment: insight into the role of lipid peroxidation in the progression and pathogenesis of Alzheimer's disease. Neurobiol Dis 2008; 30:107-20. [PMID: 18325775 DOI: 10.1016/j.nbd.2007.12.007] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 11/29/2007] [Accepted: 12/23/2007] [Indexed: 11/17/2022] Open
Abstract
Numerous investigations point to the importance of oxidative imbalance in mediating AD pathogenesis. Accumulated evidence indicates that lipid peroxidation is an early event during the evolution of the disease and occurs in patients with mild cognitive impairment (MCI). Because MCI represents a condition of increased risk for Alzheimer's disease (AD), early detection of disease markers is under investigation. Previously we showed that HNE-modified proteins, markers of lipid peroxidation, are elevated in MCI hippocampus and inferior parietal lobule compared to controls. Using a redox proteomic approach, we now report the identity of 11 HNE-modified proteins that had significantly elevated HNE levels in MCI patients compared with controls that span both brain regions: Neuropolypeptide h3, carbonyl reductase (NADPH), alpha-enolase, lactate dehydrogenase B, phosphoglycerate kinase, heat shock protein 70, ATP synthase alpha chain, pyruvate kinase, actin, elongation factor Tu, and translation initiation factor alpha. The enzyme activities of lactate dehydrogenase, ATP synthase, and pyruvate kinase were decreased in MCI subjects compared with controls, suggesting a direct correlation between oxidative damage and impaired enzyme activity. We suggest that impairment of target proteins through the production of HNE adducts leads to protein dysfunction and eventually neuronal death, thus contributing to the biological events that may lead MCI patients to progress to AD.
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Affiliation(s)
- Tanea Reed
- Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055, USA
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40
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Liron T, Seraya CB, Ish-Shalom M, Souroujon MC, Neumann D. Overexpression of amyloid precursor protein reduces epsilon protein kinase C levels. Neuroscience 2007; 146:152-9. [PMID: 17321053 DOI: 10.1016/j.neuroscience.2007.01.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Revised: 12/12/2006] [Accepted: 01/07/2007] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease (AD) is characterized by extracellular deposits of amyloid beta peptide (Abeta), a peptide that is generated upon proteolytic cleavage of amyloid precursor protein (APP). The events leading to the development of AD and their sequence are not yet fully understood. Protein kinase C (PKC) has been suggested to have a significant role in controlling neuronal degeneration and in the aberrant signal transduction taking place in AD. Several studies document a deficit in PKC levels and activity in brains of AD patients when compared with those of normal controls. Such a decrease in PKC could have serious implications since certain PKC isozymes were shown to drive the APP proteolytic cleavage into a non-amyloidogenic pathway. Reduced levels of distinct PKC isozymes could thus contribute to driving APP processing toward an amyloidogenic pathway. The direct cause for the down-regulation of PKC in AD brains is still unknown. In that respect, we tested in this study whether APP may play a role in PKC reduction. We show in three different cell lines (CHO, COS and BOSC) that overexpression of APP leads to decreased PKC levels. This decrease was found to be specific for the epsilon PKC isozyme whereas the levels of delta, alpha and conventional PKC remained unchanged. Furthermore, we observed this decrease for both active, membrane-associated and inactive, cytosolic epsilon PKC. APP-driven decrease in epsilon PKC is most likely mediated by a factor in the culture medium, since transfer of medium from cultured cells overexpressing APP to naïve, non-overexpressing cells, has also led to the selective decrease in epsilon PKC levels. Taken together, our results suggest that APP expression levels may play a role in the decrease of epsilon PKC levels in AD brains and could thus affect the responsiveness of AD brain tissues to growth factors and neurotransmitters.
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Affiliation(s)
- T Liron
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel-Aviv University, 69978 Tel-Aviv, Israel
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41
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Amadio M, Battaini F, Pascale A. The different facets of protein kinases C: old and new players in neuronal signal transduction pathways. Pharmacol Res 2006; 54:317-25. [PMID: 16996748 DOI: 10.1016/j.phrs.2006.08.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Revised: 08/08/2006] [Accepted: 08/08/2006] [Indexed: 12/01/2022]
Abstract
Signal transduction pathways are crucial for cell-to-cell communication. Various molecular cascades allow the translation of distinct stimuli, targeting the cell, into a language that the cell itself is able to understand, thus elaborating specific responses. Within this context, a strategic role is played by protein kinases which catalyze the phosphorylation of specific substrates. The serine/threonine protein kinase C (PKC) enzymes family (at least 10 isoforms) is implicated in the transduction of signals coupled to receptor-mediated hydrolysis of membrane phospholipids. Within this molecular pathway, protein-protein interactions play a critical role in directing the distinct activated PKCs towards selective subcellular compartments, in order to guarantee spatio-temporal and localized cellular responses. A space-specific modulation of biochemical events is particularly important during learning. Among the various mechanisms, the modulation of mRNA decay appears to be an efficient post-transcriptional way of controlling gene expression during learning, allowing changes to take place in selected neuronal regions, in particular at synaptic level. To this regard, recent studies have pointed out that PKC activation is also involved in a novel signalling cascade leading to the stabilization of specific mRNAs. This review will especially focus the attention on the implication of PKC in memory trace formation and how alterations within this molecular cascade may have consequences on physiological and pathological neuronal aging (i.e. Alzheimer's disease).
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Affiliation(s)
- Marialaura Amadio
- Department of Experimental and Applied Pharmacology, University of Pavia, Pavia, Italy
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42
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Boyd-Kimball D, Poon HF, Lynn BC, Cai J, Pierce WM, Klein JB, Ferguson J, Link CD, Butterfield DA. Proteomic identification of proteins specifically oxidized in Caenorhabditis elegans expressing human Aβ(1–42): Implications for Alzheimer's disease. Neurobiol Aging 2006; 27:1239-49. [PMID: 16099075 DOI: 10.1016/j.neurobiolaging.2005.07.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Revised: 05/17/2005] [Accepted: 07/01/2005] [Indexed: 10/25/2022]
Abstract
Protein oxidation has been shown to lead to loss of protein function, increased protein aggregation, decreased protein turnover, decreased membrane fluidity, altered cellular redox poteintial, loss of Ca2+ homeostaisis, and cell death. There is increasing evidence that protein oxidation is involved in the pathogenesis of Alzheimer's disease and amyloid beta-peptide (1-42) has been implicated as a mediator of oxidative stress in AD. However, the specific implications of the oxidation induced by Abeta(1-42) on the neurodegeneration evident in AD are unknown. In this study, we used proteomic techniques to identify specific targets of oxidation in transgenic Caenorhabditis elegans (C. elegans) expressing human Abeta(1-42). We identified 16 oxidized proteins involved in energy metabolism, proteasome function, and scavenging of oxidants that are more oxidized compared to control lines. These results are discussed with reference to Alzheimer's disease.
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Affiliation(s)
- Debra Boyd-Kimball
- Department of Chemistry, Center of Membrane Sciences, and Sanders-Brown Center on Aging, 121 Chemistry-Physics Building, University of Kentucky, Lexington, KY 40506-0055, USA
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43
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Tsang SWY, Pomakian J, Marshall GA, Vinters HV, Cummings JL, Chen CPLH, Wong PTH, Lai MKP. Disrupted muscarinic M1 receptor signaling correlates with loss of protein kinase C activity and glutamatergic deficit in Alzheimer's disease. Neurobiol Aging 2006; 28:1381-7. [PMID: 16828202 DOI: 10.1016/j.neurobiolaging.2006.06.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 04/08/2006] [Accepted: 06/02/2006] [Indexed: 11/21/2022]
Abstract
There are few studies on the clinical and neurochemical correlates of postsynaptic cholinergic dysfunction in Alzheimer's disease (AD). We have previously found that attenuation of guanine nucleotide-binding (G-) protein coupling to muscarinic M(1) receptors in the neocortex was associated with dementia severity. The present study aims to study whether this loss of M(1)/G-protein coupling is related to alterations in signaling kinases and NMDA receptors. Postmortem frontal cortices of 22 AD subjects and 12 elderly controls were obtained to measure M(1) receptors, M(1)/G-protein coupling, NMDA receptors as well as protein kinase C (PKC) and Src kinase activities. We found that the extent of M(1)/G-protein coupling loss was correlated with reductions in PKC activity and NMDA receptor density. In contrast, Src kinase activity was neither altered nor associated with M(1)/G-protein coupling. Given the well established roles of neuronal PKC signaling and NMDA receptor function in cognitive processes, our results lend further insight into the mechanisms by which postsynaptic cholinergic dysfunction may underlie the cognitive features of AD, and suggest alternative therapeutic targets to cholinergic replacement.
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Affiliation(s)
- Shirley W Y Tsang
- Dementia Research Laboratory, Department of Clinical Research, Singapore General Hospital, Singapore
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44
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Sklan EH, Podoly E, Soreq H. RACK1 has the nerve to act: structure meets function in the nervous system. Prog Neurobiol 2006; 78:117-34. [PMID: 16457939 DOI: 10.1016/j.pneurobio.2005.12.002] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2005] [Revised: 11/20/2005] [Accepted: 12/07/2005] [Indexed: 11/26/2022]
Abstract
The receptor for activated protein kinase C 1 (RACK1) is an intracellular adaptor protein. Accumulating evidence attributes to this member of the tryptophan-aspartate (WD) repeat family the role of regulating several major nervous system pathways. Structurally, RACK1 is a seven-bladed-beta-propeller, interacting with diverse proteins having distinct structural folds. When bound to the IP3 receptor, RACK1 regulates intracellular Ca2+ levels, potentially contributing to processes such as learning, memory and synaptic plasticity. By binding to the NMDA receptor, it dictates neuronal excitation and sensitivity to ethanol. When bound to the stress-induced acetylcholinesterase variant AChE-R, RACK1 is implicated in stress responses and behavior, compatible with reports of RACK1 modulations in brain ageing and in various neurodegenerative diseases. This review sheds new light on both the virtues and the variety of neuronal RACK1 interactions and their physiological consequences.
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Affiliation(s)
- Ella H Sklan
- The Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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45
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Ashique AM, Kharazia V, Yaka R, Phamluong K, Peterson AS, Ron D. Localization of the scaffolding protein RACK1 in the developing and adult mouse brain. Brain Res 2006; 1069:31-8. [PMID: 16414032 DOI: 10.1016/j.brainres.2005.11.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Revised: 11/08/2005] [Accepted: 11/09/2005] [Indexed: 11/20/2022]
Abstract
RACK1 is a multifunctional scaffolding protein known to be involved in the regulation of various signaling cascades in the central nervous system (CNS). In order to gain insight into the neurological functions of RACK1, we examined the expression of RACK1 mRNA and protein during gestation and in the adult mouse brain. Several expression patterns were observed. At embryonic day 11.5 (E11.5), RACK1 is expressed in a high-dorsal to low-ventral gradient throughout the brain. At E13.5, RACK1 is most abundant in the telencephalon. In the developing cortical primordium, RACK1 protein is expressed in a high-rostromidline to low-caudolateral gradient that appears to be regulated post-transcriptionally. At E18.5, RACK1 is expressed most abundantly in layers 1-4 of the cortex, striatum, hippocampus, dentate gyrus and specific thalamic nuclei. In the adult mouse, RACK1 is ubiquitously expressed in neuronal perikarya in most brain regions, with relatively higher levels in hippocampus, olfactory bulb, cortex and cerebellum. Subcellular staining was detected mainly in the cell bodies and extending into dendrites, whereas RACK1 was not present significantly in axonal fibers or nuclei. We also determined brain regions in which RACK1 interacts with one of its binding partners, the betaII isoform of protein kinase C (betaIIPKC). We found that betaIIPKC had a much more restricted expression pattern than RACK1 and overlapped with the scaffolding protein only in certain regions, including the CA1 area of the hippocampus, cerebellum and striatum. Our results suggest an important role for RACK1 during CNS development and support multiple functions of the protein in the adult brain.
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Affiliation(s)
- A M Ashique
- Ernest Gallo Clinic and Research Center, University of California San Francisco, 5858 Horton St., Suite 200, Emeryville, CA 94608, USA
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Mandel S, Weinreb O, Amit T, Youdim MBH. Mechanism of neuroprotective action of the anti-Parkinson drug rasagiline and its derivatives. ACTA ACUST UNITED AC 2005; 48:379-87. [PMID: 15850677 DOI: 10.1016/j.brainresrev.2004.12.027] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2004] [Accepted: 12/09/2004] [Indexed: 01/01/2023]
Abstract
The mitochondria are directly involved in cell survival and death. Drugs that protect mitochondria viability and prevent apoptotic cascade mechanisms involved in mitochondrial permeability transition pore (MPTp) will be cytoprotective. Rasagiline (N-propargyl-1R-aminoindan) is a novel, highly potent irreversible monoamine oxidase (MAO) B inhibitor, anti-Parkinson drug. Unlike selegiline, rasagiline is not derived from amphetamine, is not metabolized to neurotoxic l-methamphetamine derivative, nor does it have sympathomimetic activity. Rasagiline is effective as monotherapy or adjunct to L-dopa for patients with early and late Parkinson's disease (PD), and adverse events do not occur with greater frequency in subjects receiving rasagiline than those on placebo. Controlled studies indicate that it might have a disease-modifying effect in PD that may be related to neuroprotection. Its S-isomer, TVP1022, is a relatively inactive MAO inhibitor. However, both drugs have similar neuroprotective activities in neuronal cell cultures in response to various neurotoxins and in vivo (global ischemia, neurotrauma, head injury, anoxia, etc.), indicating that MAO inhibition is not a pre-requisite for neuroprotection. Structure activity studies have shown that the neuroprotective activity is associated with the propargyl moiety of rasagiline which protects mitochondrial viability and MPTp by activating Bcl-2 and protein kinase C (PKC), and down regulating pro-apoptotic FAS and Bax. Rasagiline and its derivatives also process amyloid precursor protein (APP) to the neuroprotective-neurotrophic soluble APP alpha (sAPPalpha) by PKC and MAP kinase-dependent activation of alpha-secretase. The neuroprotective activity of propargylamine has led us to develop novel bifunctional neuroprotective iron-chelating MAO-inhibiting drugs possessing propargyl moiety for the treatment of other neurodegenerative diseases.
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Affiliation(s)
- Silvia Mandel
- Eve Topf and NPF Centers of Excellence for Neurodegenerative Diseases Research, Israel
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47
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Van der Zee EA, Palm IF, O'Connor M, Maizels ET, Hunzicker-Dunn M, Disterhoft JF. Aging-related alterations in the distribution of Ca(2+)-dependent PKC isoforms in rabbit hippocampus. Hippocampus 2005; 14:849-60. [PMID: 15382255 DOI: 10.1002/hipo.20000] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The immunocytochemical and subcellular localization of the Ca(2+)-dependent protein kinase C (cPKC) isoforms (PKCalpha, beta1, beta2, and gamma) was examined in rabbit hippocampus of young (3 months of age; n = 11) and aging (36 months of age; n = 14) subjects. Detailed immunocytochemical analyses revealed a significant increase in PKCbeta1, beta2, and gamma immunoreactivity in principal cell bodies and associated dendrites, and interneurons of the hilar region in the aging rabbits. The number of PKCalpha- and gamma-positive interneurons in the aging stratum oriens declined significantly. PKCalpha was least affected in principal cells, showing an increase in immunostaining in granule cells only. Weakly PKC-positive principal cells intermingled between densely stained ones were seen in parts of the hippocampus in most of the aging rabbits, showing that the degree of aging-related alterations in PKC-immunoreactivity varies between neurons. Changes in PKC expression in the molecular and subgranular layer of the aging dentate gyrus suggested a reorganization of PKC-positive afferents to this region. Western blot analysis revealed a significant loss of PKC in the pellet fraction for all isoforms, and a tendency for increased levels of cytosolic PKC. However, no significant changes were found in total PKC content for any PKC isoform. A concurrent dramatic loss of the PKC anchoring protein receptor for activated C kinase (RACK1) in the pellet fraction was shown by Western blotting. These findings suggest that the loss of RACK1 contributes to the dysregulation of the PKC system in the aging rabbit hippocampus. The enhanced PKC-immunoreactivity might relate to reduced protein-protein interactions of PKC with the anchoring protein RACK1 leading to increased access of the antibodies to the antigenic site. In conclusion, the results suggest that memory deficits in aging rabbits are (in part) caused by dysregulation of subcellular PKC localization in hippocampal neurons.
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Affiliation(s)
- E A Van der Zee
- Department of Molecular Neurobiology, University of Groningen, Groningen, The Netherlands.
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48
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Soreq H, Yirmiya R, Cohen O, Glick D. Acetylcholinesterase as a window onto stress responses. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s0921-0709(05)80032-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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49
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Olariu A, Yamada K, Nabeshima T. Amyloid Pathology and Protein Kinase C (PKC): Possible Therapeutics Effects of PKC Activators. J Pharmacol Sci 2005; 97:1-5. [PMID: 15655301 DOI: 10.1254/jphs.cpj04004x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Amyloid beta-protein (Abeta) is one of the most studied peptides in human neurodegenerative disorders. Although much has been learned about the biochemistry of this peptide, fundamental questions such as when and how the Abeta becomes pathologic remain unanswered. In this article we review the recent findings on the biology and pathology of Abeta and the role protein kinase C (PKC) plays in these processes. The potential neuroprotective role of PKC and the possible therapeutic effects of PKC activators in Alzheimer's disease (AD) will be discussed. Briefly, comments will be also addressed on the role of PKC in cell death and neurogenesis in AD.
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Affiliation(s)
- Ana Olariu
- Unit on Neuroplasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
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50
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Pascale A, Alkon DL, Grimaldi M. Translocation of protein kinase C-betaII in astrocytes requires organized actin cytoskeleton and is not accompanied by synchronous RACK1 relocation. Glia 2004; 46:169-82. [PMID: 15042584 DOI: 10.1002/glia.10354] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Protein kinase C (PKC)-betaII is the most abundant PKC isoform in astrocytes. Upon activation, this isoform of PKC translocates from the cytosol to the plasma membrane (PM). In this study, we investigated in astrocytes the modality of PKC-betaII translocation as far as the participation of the receptor for activated C kinase-1 (RACK1) and the requirement for intact cytoskeleton in the process. In astrocytes, Western blots and immunocytochemistry coupled to confocal microscopic quantitative analysis showed that after 5 min of phorbol-12-myristate-13-acetate (PMA) exposure, native PKC-betaII, but not PKC-betaI, is relocated efficiently from the cytosol to the PM. Translocation of PKC-betaII was not associated with synchronous RACK1 relocation. Furthermore, the quantity of PM-associated PKC-betaII that co-immunoprecipitated with PM-bound RACK1 increased following PMA exposure, indicating a post activation binding of the two proteins in the PM. Because RACK1 and PKC-betaII relocation seemed not to be synchronous, we hypothesized that an intermediate interaction with the cytoskeleton was taking place. In fact, we were able to show that pharmacological disruption of actin-based cytoskeleton greatly deranged PKC-betaII translocation to the PM. The requirement for intact actin cytoskeleton was specific, because depolymerization of tubulin had no effect on the ability of the kinase to translocate to the PM. These results indicate that in astrocytes, RACK1 and PKC-betaII synchronous relocation is not essential for relocation of PKC-betaII to the PM. In addition, we show for the first time that the integrity of the actin cytoskeleton plays a specific role in PKC-betaII movements in these cells. We hypothesize that in glial cells, rapidly occurring changes of actin cytoskeleton arrangement may be involved in the fast reprogramming of PKC targeting to specific PM location to phosphorylate substrates in different cellular locations.
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Affiliation(s)
- Alessia Pascale
- Laboratory of Adaptive Systems, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland, USA
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