1
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Vrabec R, Blunden G, Cahlíková L. Natural Alkaloids as Multi-Target Compounds towards Factors Implicated in Alzheimer's Disease. Int J Mol Sci 2023; 24:ijms24054399. [PMID: 36901826 PMCID: PMC10003045 DOI: 10.3390/ijms24054399] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/20/2023] [Accepted: 02/21/2023] [Indexed: 02/25/2023] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in elderly people; currently, there is no efficient treatment. Considering the increase in life expectancy worldwide AD rates are predicted to increase enormously, and thus the search for new AD drugs is urgently needed. A great amount of experimental and clinical evidence indicated that AD is a complex disorder characterized by widespread neurodegeneration of the CNS, with major involvement of the cholinergic system, causing progressive cognitive decline and dementia. The current treatment, based on the cholinergic hypothesis, is only symptomatic and mainly involves the restoration of acetylcholine (ACh) levels through the inhibition of acetylcholinesterase (AChE). Since the introduction of the Amaryllidaceae alkaloid galanthamine as an antidementia drug in 2001, alkaloids have been one of the most attractive groups for searching for new AD drugs. The present review aims to comprehensively summarize alkaloids of various origins as multi-target compounds for AD. From this point of view, the most promising compounds seem to be the β-carboline alkaloid harmine and several isoquinoline alkaloids since they can simultaneously inhibit several key enzymes of AD's pathophysiology. However, this topic remains open for further research on detailed mechanisms of action and the synthesis of potentially better semi-synthetic analogues.
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Affiliation(s)
- Rudolf Vrabec
- Secondary Metabolites of Plants as Potential Drugs Research Group, Department of Pharmacognosy and Pharmaceutical Botany, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - Gerald Blunden
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DT, UK
| | - Lucie Cahlíková
- Secondary Metabolites of Plants as Potential Drugs Research Group, Department of Pharmacognosy and Pharmaceutical Botany, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
- Correspondence:
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2
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Lin IH, Kamnaksh A, Aniceto R, McCullough J, Bekdash R, Eklund M, Ghatan PH, Risling M, Svensson M, Bellander BM, Nelson DW, Thelin EP, Agoston DV. Time-Dependent Changes in the Biofluid Levels of Neural Injury Markers in Severe Traumatic Brain Injury Patients-Cerebrospinal Fluid and Cerebral Microdialysates: A Longitudinal Prospective Pilot Study. Neurotrauma Rep 2023; 4:107-117. [PMID: 36895820 PMCID: PMC9989523 DOI: 10.1089/neur.2022.0076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023] Open
Abstract
Monitoring protein biomarker levels in the cerebrospinal fluid (CSF) can help assess injury severity and outcome after traumatic brain injury (TBI). Determining injury-induced changes in the proteome of brain extracellular fluid (bECF) can more closely reflect changes in the brain parenchyma, but bECF is not routinely available. The aim of this pilot study was to compare time-dependent changes of S100 calcium-binding protein B (S100B), neuron-specific enolase (NSE), total Tau, and phosphorylated Tau (p-Tau) levels in matching CSF and bECF samples collected at 1, 3, and 5 days post-injury from severe TBI patients (n = 7; GCS 3-8) using microcapillary-based western analysis. We found that time-dependent changes in CSF and bECF levels were most pronounced for S100B and NSE, but there was substantial patient-to-patient variability. Importantly, the temporal pattern of biomarker changes in CSF and bECF samples showed similar trends. We also detected two different immunoreactive forms of S100B in both CSF and bECF samples, but the contribution of the different immunoreactive forms to total immunoreactivity varied from patient to patient and time point to time point. Our study is limited, but it illustrates the value of both quantitative and qualitative analysis of protein biomarkers and the importance of serial sampling for biofluid analysis after severe TBI.
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Affiliation(s)
- I-Hsuan Lin
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, Maryland, USA
| | - Alaa Kamnaksh
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, Maryland, USA
| | - Roxanne Aniceto
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, Maryland, USA
| | - Jesse McCullough
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, Maryland, USA
| | - Ramsey Bekdash
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, Maryland, USA
| | - Michael Eklund
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, Maryland, USA
| | - Per Hamid Ghatan
- Department of Neuroscience, Uppsala University Hospital, Uppsala, Sweden
| | - Mårten Risling
- Department of Neuroscience, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Mikael Svensson
- Department of Clinical Neuroscience, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Department of Neurosurgery, Karolinska University Hospital, Stockholm, Sweden
| | - Bo-Michael Bellander
- Department of Clinical Neuroscience, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Department of Neurosurgery, Karolinska University Hospital, Stockholm, Sweden
| | - David W Nelson
- Department of Perioperative Medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden.,Section of Perioperative Medicine and Intensive Care, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Eric Peter Thelin
- Department of Clinical Neuroscience, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Department of Neurology, Karolinska University Hospital, Stockholm, Sweden
| | - Denes V Agoston
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, Maryland, USA
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3
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Korde DS, Humpel C. Spreading of P301S Aggregated Tau Investigated in Organotypic Mouse Brain Slice Cultures. Biomolecules 2022; 12:biom12091164. [PMID: 36139003 PMCID: PMC9496515 DOI: 10.3390/biom12091164] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/06/2022] [Accepted: 08/16/2022] [Indexed: 11/16/2022] Open
Abstract
Tau pathology extends throughout the brain in a prion-like fashion through connected brain regions. However, the details of the underlying mechanisms are incompletely understood. The present study aims to examine the spreading of P301S aggregated tau, a mutation that is implicated in tauopathies, using organotypic slice cultures. Coronal hippocampal organotypic brain slices (170 µm) were prepared from postnatal (day 8–10) C57BL6 wild-type mice. Collagen hydrogels loaded with P301S aggregated tau were applied to slices and the spread of tau was assessed by immunohistochemistry after 8 weeks in culture. Collagen hydrogels prove to be an effective protein delivery system subject to natural degradation in 14 days and they release tau proteins up to 8 weeks. Slices with un- and hyperphosphorylated P301S aggregated tau demonstrate significant spreading to the ventral parts of the hippocampal slices compared to empty collagen hydrogels after 8 weeks. Moreover, the spread of P301S aggregated tau occurs in a time-dependent manner, which was interrupted when the neuroanatomical pathways are lesioned. We illustrate that the spreading of tau can be investigated in organotypic slice cultures using collagen hydrogels to achieve a localized application and slow release of tau proteins. P301S aggregated tau significantly spreads to the ventral areas of the slices, suggesting that the disease-relevant aggregated tau form possesses spreading potential. Thus, the results offer a novel experimental approach to investigate tau pathology.
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4
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Jangampalli Adi P, Reddy PH. Phosphorylated tau targeted small-molecule PROTACs for the treatment of Alzheimer's disease and tauopathies. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166162. [PMID: 33940164 DOI: 10.1016/j.bbadis.2021.166162] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 10/21/2022]
Abstract
Tau is a microtubule-stabilizing protein that plays an important role in the formation of axonal microtubules in neurons. Phosphorylated tau (p-Tau) has received great attention in the field of Alzheimer's disease (AD) as a potential therapeutic target due to its involvement with synaptic damage and neuronal dysfunction. Mounting evidence suggests that amyloid beta (Aβ)-targeted clinical trials continuously failed; therefore, it is important to consider alternative therapeutic strategies such as p-tau-PROTACs targeted small molecules for AD and other tauopathies. The present article describes the characteristics of tau biology, structure, and function in both healthy and pathological states in AD. It also explains data from studies that have identified the involvement of p-tau in neuronal damage and synaptic and cognitive functions in AD. Current article also covers several aspects, including small molecule inhibitors, and the development of p-tau-PROTACs targeted drug molecules to treat patients with AD and other tauopathies.
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Affiliation(s)
| | - P Hemachandra Reddy
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Public Health, Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Speech, Language, and Hearing Sciences, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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5
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Mueller RL, Combs B, Alhadidy MM, Brady ST, Morfini GA, Kanaan NM. Tau: A Signaling Hub Protein. Front Mol Neurosci 2021; 14:647054. [PMID: 33815057 PMCID: PMC8017207 DOI: 10.3389/fnmol.2021.647054] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/23/2021] [Indexed: 12/23/2022] Open
Abstract
Over four decades ago, in vitro experiments showed that tau protein interacts with and stabilizes microtubules in a phosphorylation-dependent manner. This observation fueled the widespread hypotheses that these properties extend to living neurons and that reduced stability of microtubules represents a major disease-driving event induced by pathological forms of tau in Alzheimer’s disease and other tauopathies. Accordingly, most research efforts to date have addressed this protein as a substrate, focusing on evaluating how specific mutations, phosphorylation, and other post-translational modifications impact its microtubule-binding and stabilizing properties. In contrast, fewer efforts were made to illuminate potential mechanisms linking physiological and disease-related forms of tau to the normal and pathological regulation of kinases and phosphatases. Here, we discuss published work indicating that, through interactions with various kinases and phosphatases, tau may normally act as a scaffolding protein to regulate phosphorylation-based signaling pathways. Expanding on this concept, we also review experimental evidence linking disease-related tau species to the misregulation of these pathways. Collectively, the available evidence supports the participation of tau in multiple cellular processes sustaining neuronal and glial function through various mechanisms involving the scaffolding and regulation of selected kinases and phosphatases at discrete subcellular compartments. The notion that the repertoire of tau functions includes a role as a signaling hub should widen our interpretation of experimental results and increase our understanding of tau biology in normal and disease conditions.
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Affiliation(s)
- Rebecca L Mueller
- Department of Translational Neuroscience, Michigan State University, Grand Rapids, MI, United States.,Neuroscience Program, Michigan State University, East Lansing, MI, United States
| | - Benjamin Combs
- Department of Translational Neuroscience, Michigan State University, Grand Rapids, MI, United States
| | - Mohammed M Alhadidy
- Department of Translational Neuroscience, Michigan State University, Grand Rapids, MI, United States.,Neuroscience Program, Michigan State University, East Lansing, MI, United States
| | - Scott T Brady
- Department of Anatomy and Cell Biology, The University of Illinois at Chicago, Chicago, IL, United States.,Marine Biological Laboratory, Woods Hole, MA, United States
| | - Gerardo A Morfini
- Department of Anatomy and Cell Biology, The University of Illinois at Chicago, Chicago, IL, United States.,Marine Biological Laboratory, Woods Hole, MA, United States
| | - Nicholas M Kanaan
- Department of Translational Neuroscience, Michigan State University, Grand Rapids, MI, United States.,Neuroscience Program, Michigan State University, East Lansing, MI, United States.,Hauenstein Neuroscience Center, Mercy Health Saint Mary's, Grand Rapids, MI, United States
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6
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Baker JD, Uhrich RL, Strovas TJ, Saxton AD, Kraemer BC. AlphaScreen Identifies MSUT2 Inhibitors for Tauopathy-Targeting Therapeutic Discovery. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2021; 26:400-409. [PMID: 32981422 PMCID: PMC8592089 DOI: 10.1177/2472555220958387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tauopathies are neurological disorders characterized by intracellular tau deposits forming neurofibrillary tangles, neuropil threads, or other disease-specific aggregates composed of the protein tau. Tauopathy disorders include frontotemporal lobar degeneration, corticobasal degeneration, Pick's disease, and the largest cause of dementia, Alzheimer's disease. The lack of disease-modifying therapeutic strategies to address tauopathies remains a critical unmet need in dementia care. Thus, novel broad-spectrum tau-targeted therapeutics could have a profound impact in multiple tauopathy disorders, including Alzheimer's disease. Here we have designed a drug discovery paradigm to identify inhibitors of the pathological tau-enabling protein, MSUT2. We previously showed that activity of the RNA-binding protein MSUT2 drives tauopathy, including tau-mediated neurodegeneration and cognitive dysfunction, in mouse models. Thus, we hypothesized that MSUT2 inhibitors could be therapeutic for tauopathy disorders. Our pipeline for MSUT2 inhibitory compound identification included a primary AlphaScreen, followed by dose-response validation, a secondary fluorescence polarization orthogonal assay, a tertiary specificity screen, and a preliminary toxicity screen. Our work here serves as a proof-of-principle methodology for finding specific inhibitors of the poly(A) RNA-binding protein MSUT2 interaction. Here we identify 4,4'-diisothiocyanostilbene-2,2'-sulfonic acid (DIDS) as a potential tool compound for future work probing the mechanism of MSUT2-induced tau pathology.
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Affiliation(s)
- Jeremy D. Baker
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, WA, USA
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Rikki L. Uhrich
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Timothy J. Strovas
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Aleen D. Saxton
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Brian C. Kraemer
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, WA, USA
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
- Department of Pathology, University of Washington, Seattle, WA, USA
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7
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Muralidar S, Ambi SV, Sekaran S, Thirumalai D, Palaniappan B. Role of tau protein in Alzheimer's disease: The prime pathological player. Int J Biol Macromol 2020; 163:1599-1617. [PMID: 32784025 DOI: 10.1016/j.ijbiomac.2020.07.327] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/07/2020] [Accepted: 07/31/2020] [Indexed: 01/11/2023]
Abstract
Alzheimer's disease (AD) is a prevalently found tauopathy characterized by memory loss and cognitive insufficiency. AD is an age-related neurodegenerative disease with two major hallmarks which includes extracellular amyloid plaques made of amyloid-β (Aβ) and intracellular neurofibrillary tangles of hyperphosphorylated tau. With population aging worldwide, there is an indispensable need for treatment strategies that can potentially manage this developing dementia. Despite broad researches on targeting Aβ in the past two decades, research findings on Aβ targeted therapeutics failed to prove efficacy in the treatment of AD. Tau protein with its extensive pathological role in several neurodegenerative diseases can be considered as a promising target candidate for developing therapeutic interventions. The abnormal hyperphosphorylation of tau plays detrimental pathological functions which ultimately lead to neurodegeneration. This review will divulge the importance of tau in AD pathogenesis, the interplay of Aβ and tau, the pathological functions of tau, and potential therapeutic strategies for an effective management of neuronal disorders.
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Affiliation(s)
- Shibi Muralidar
- School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India
| | - Senthil Visaga Ambi
- School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India.
| | - Saravanan Sekaran
- School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India; Centre for Nanotechnology & Advanced Biomaterials (CeNTAB), School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India
| | - Diraviyam Thirumalai
- School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India
| | - Balamurugan Palaniappan
- School of Chemical and Biotechnology, SASTRA Deemed-to-be-University, Thanjavur 613401, Tamil Nadu, India
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8
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Das R, Balmik AA, Chinnathambi S. Phagocytosis of full-length Tau oligomers by Actin-remodeling of activated microglia. J Neuroinflammation 2020; 17:10. [PMID: 31915009 PMCID: PMC6950897 DOI: 10.1186/s12974-019-1694-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/29/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Alzheimer's disease is associated with the accumulation of intracellular Tau tangles within neurons and extracellular amyloid-β plaques in the brain parenchyma, which altogether results in synaptic loss and neurodegeneration. Extracellular concentrations of oligomers and aggregated proteins initiate microglial activation and convert their state of synaptic surveillance into a destructive inflammatory state. Although Tau oligomers have fleeting nature, they were shown to mediate neurotoxicity and microglial pro-inflammation. Due to the instability of oligomers, in vitro experiments become challenging, and hence, the stability of the full-length Tau oligomers is a major concern. METHODS In this study, we have prepared and stabilized hTau40WT oligomers, which were purified by size-exclusion chromatography. The formation of the oligomers was confirmed by western blot, thioflavin-S, 8-anilinonaphthaalene-1-sulfonic acid fluorescence, and circular dichroism spectroscopy, which determine the intermolecular cross-β sheet structure and hydrophobicity. The efficiency of N9 microglial cells to phagocytose hTau40WT oligomer and subsequent microglial activation was studied by immunofluorescence microscopy with apotome. The one-way ANOVA was performed for the statistical analysis of fluorometric assay and microscopic analysis. RESULTS Full-length Tau oligomers were detected in heterogeneous globular structures ranging from 5 to 50 nm as observed by high-resolution transmission electron microscopy, which was further characterized by oligomer-specific A11 antibody. Immunocytochemistry studies for oligomer treatment were evidenced with A11+ Iba1high microglia, suggesting that the phagocytosis of extracellular Tau oligomers leads to microglial activation. Also, the microglia were observed with remodeled filopodia-like actin structures upon the exposure of oligomers and aggregated Tau. CONCLUSION The peri-membrane polymerization of actin filament and co-localization of Iba1 relate to the microglial movements for phagocytosis. Here, these findings suggest that microglia modified actin cytoskeleton for phagocytosis and rapid clearance of Tau oligomers in Alzheimer's disease condition.
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Affiliation(s)
- Rashmi Das
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Pune, 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Pune, 411008, India
| | - Abhishek Ankur Balmik
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Pune, 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Pune, 411008, India
| | - Subashchandrabose Chinnathambi
- Neurobiology Group, Division of Biochemical Sciences, CSIR-National Chemical Laboratory (CSIR-NCL), Pune, 411008, India. .,Academy of Scientific and Innovative Research (AcSIR), Pune, 411008, India.
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9
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Clark AR, Ohlmeyer M. Protein phosphatase 2A as a therapeutic target in inflammation and neurodegeneration. Pharmacol Ther 2019; 201:181-201. [PMID: 31158394 PMCID: PMC6700395 DOI: 10.1016/j.pharmthera.2019.05.016] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 05/29/2019] [Indexed: 12/11/2022]
Abstract
Protein phosphatase 2A (PP2A) is a highly complex heterotrimeric enzyme that catalyzes the selective removal of phosphate groups from protein serine and threonine residues. Emerging evidence suggests that it functions as a tumor suppressor by constraining phosphorylation-dependent signalling pathways that regulate cellular transformation and metastasis. Therefore, PP2A-activating drugs (PADs) are being actively sought and investigated as potential novel anti-cancer treatments. Here we explore the concept that PP2A also constrains inflammatory responses through its inhibitory effects on various signalling pathways, suggesting that PADs may be effective in the treatment of inflammation-mediated pathologies.
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Affiliation(s)
- Andrew R Clark
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
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10
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Pradeepkiran JA, Reddy AP, Reddy PH. Pharmacophore-based models for therapeutic drugs against phosphorylated tau in Alzheimer's disease. Drug Discov Today 2018; 24:616-623. [PMID: 30453058 DOI: 10.1016/j.drudis.2018.11.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 09/22/2018] [Accepted: 11/07/2018] [Indexed: 10/27/2022]
Abstract
Phosphorylated tau (P-tau) has received much attention in the field of Alzheimer's disease (AD), as a potential therapeutic target owing to its involvement with synaptic damage and neuronal dysfunction. The continuous failure of amyloid β (Aβ)-targeted therapeutics highlights the urgency to consider alternative therapeutic strategies for AD. The present review describes the latest developments in tau biology and function. It also explains abnormal interactions between P-tau with Aβ and the mitochondrial fission protein Drp1, leading to excessive mitochondrial fragmentation and synaptic damage in AD neurons. This article also addresses 3D pharmacophore-based drug models designed to treat patients with AD and other tauopathies.
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Affiliation(s)
- Jangampalli Adi Pradeepkiran
- Garrison Institute on Aging, Texas Tech University Health Sciences Center, 3601 4th Street, MS 9424, Lubbock, TX 79430, USA
| | - Arubala P Reddy
- Pharmacology & Neuroscience Department, Texas Tech University Health Sciences Center, 3601 4th Street, MS 9424, Lubbock, TX 79430, USA
| | - P Hemachandra Reddy
- Garrison Institute on Aging, Texas Tech University Health Sciences Center, 3601 4th Street, MS 9424, Lubbock, TX 79430, USA; Cell Biology & Biochemistry Department, Texas Tech University Health Sciences Center, 3601 4th Street, MS 9424, Lubbock, TX 79430, USA; Pharmacology & Neuroscience Department, Texas Tech University Health Sciences Center, 3601 4th Street, MS 9424, Lubbock, TX 79430, USA; Neurology Department, Texas Tech University Health Sciences Center, 3601 4th Street, MS 9424, Lubbock, TX 79430, USA; Speech, Language and Hearing Sciences Departments, Texas Tech University Health Sciences Center, 3601 4th Street, MS 9424, Lubbock, TX 79430, USA; Garrison Institute on Aging, South West Campus, Texas Tech University Health Sciences Center, 6630 S. Quaker Suite E, MS 7495, Lubbock, TX 79413, USA.
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11
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Phosphorylation of huntingtin at residue T3 is decreased in Huntington's disease and modulates mutant huntingtin protein conformation. Proc Natl Acad Sci U S A 2017; 114:E10809-E10818. [PMID: 29162692 PMCID: PMC5740681 DOI: 10.1073/pnas.1705372114] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Posttranslational modifications can have profound effects on the biological and biophysical properties of proteins associated with misfolding and aggregation. However, their detection and quantification in clinical samples and an understanding of the mechanisms underlying the pathological properties of misfolding- and aggregation-prone proteins remain a challenge for diagnostics and therapeutics development. We have applied an ultrasensitive immunoassay platform to develop and validate a quantitative assay for detecting a posttranslational modification (phosphorylation at residue T3) of a protein associated with polyglutamine repeat expansion, namely Huntingtin, and characterized its presence in a variety of preclinical and clinical samples. We find that T3 phosphorylation is greatly reduced in samples from Huntington's disease models and in Huntington's disease patients, and we provide evidence that bona-fide T3 phosphorylation alters Huntingtin exon 1 protein conformation and aggregation properties. These findings have significant implications for both mechanisms of disease pathogenesis and the development of therapeutics and diagnostics for Huntington's disease.
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12
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Ross JL. The Dark Matter of Biology. Biophys J 2017; 111:909-16. [PMID: 27602719 PMCID: PMC5018137 DOI: 10.1016/j.bpj.2016.07.037] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/06/2016] [Accepted: 07/26/2016] [Indexed: 02/04/2023] Open
Abstract
The inside of the cell is full of important, yet invisible species of molecules and proteins that interact weakly but couple together to have huge and important effects in many biological processes. Such “dark matter” inside cells remains mostly hidden, because our tools were developed to investigate strongly interacting species and folded proteins. Example dark-matter species include intrinsically disordered proteins, posttranslational states, ion species, and rare, transient, and weak interactions undetectable by biochemical assays. The dark matter of biology is likely to have multiple, vital roles to regulate signaling, rates of reactions, water structure and viscosity, crowding, and other cellular activities. We need to create new tools to image, detect, and understand these dark-matter species if we are to truly understand fundamental physical principles of biology.
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Affiliation(s)
- Jennifer L Ross
- Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts.
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13
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Gibbs EB, Cook EC, Showalter SA. Application of NMR to studies of intrinsically disordered proteins. Arch Biochem Biophys 2017; 628:57-70. [PMID: 28502465 DOI: 10.1016/j.abb.2017.05.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 05/08/2017] [Accepted: 05/10/2017] [Indexed: 12/20/2022]
Abstract
The prevalence of intrinsically disordered protein regions, particularly in eukaryotic proteins, and their clear functional advantages for signaling and gene regulation have created an imperative for high-resolution structural and mechanistic studies. NMR spectroscopy has played a central role in enhancing not only our understanding of the intrinsically disordered native state, but also how that state contributes to biological function. While pathological functions associated with protein aggregation are well established, it has recently become clear that disordered regions also mediate functionally advantageous assembly into high-order structures that promote the formation of membrane-less sub-cellular compartments and even hydrogels. Across the range of functional assembly states accessed by disordered regions, post-translational modifications and regulatory macromolecular interactions, which can also be investigated by NMR spectroscopy, feature prominently. Here we will explore the many ways in which NMR has advanced our understanding of the physical-chemical phase space occupied by disordered protein regions and provide prospectus for the future role of NMR in this emerging and exciting field.
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Affiliation(s)
- Eric B Gibbs
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Erik C Cook
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Scott A Showalter
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA; Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
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Wasser CR, Herz J. Reelin: Neurodevelopmental Architect and Homeostatic Regulator of Excitatory Synapses. J Biol Chem 2016; 292:1330-1338. [PMID: 27994051 DOI: 10.1074/jbc.r116.766782] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Over half a century ago, D. S. Falconer first reported a mouse with a reeling gate. Four decades later, the Reln gene was isolated and identified as the cause of the reeler phenotype. Initial studies found that loss of Reelin, a large, secreted glycoprotein encoded by the Reln gene, results in abnormal neuronal layering throughout several regions of the brain. In the years since, the known functions of Reelin signaling in the brain have expanded to include multiple postdevelopmental neuromodulatory roles, revealing an ever increasing body of evidence to suggest that Reelin signaling is a critical player in the modulation of synaptic function. In writing this review, we intend to highlight the most fundamental aspects of Reelin signaling and integrate how these various neuromodulatory effects shape and protect synapses.
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Affiliation(s)
- Catherine R Wasser
- From the Department of Molecular Genetics.,Center for Translational Neurodegeneration Research, and
| | - Joachim Herz
- From the Department of Molecular Genetics, .,Center for Translational Neurodegeneration Research, and.,Department of Neuroscience.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, 75390
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Del Prete D, Rice RC, Rajadhyaksha AM, D'Adamio L. Amyloid Precursor Protein (APP) May Act as a Substrate and a Recognition Unit for CRL4CRBN and Stub1 E3 Ligases Facilitating Ubiquitination of Proteins Involved in Presynaptic Functions and Neurodegeneration. J Biol Chem 2016; 291:17209-27. [PMID: 27325702 DOI: 10.1074/jbc.m116.733626] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Indexed: 12/23/2022] Open
Abstract
The amyloid precursor protein (APP), whose mutations cause Alzheimer disease, plays an important in vivo role and facilitates transmitter release. Because the APP cytosolic region (ACR) is essential for these functions, we have characterized its brain interactome. We found that the ACR interacts with proteins that regulate the ubiquitin-proteasome system, predominantly with the E3 ubiquitin-protein ligases Stub1, which binds the NH2 terminus of the ACR, and CRL4(CRBN), which is formed by Cul4a/b, Ddb1, and Crbn, and interacts with the COOH terminus of the ACR via Crbn. APP shares essential functions with APP-like protein-2 (APLP2) but not APP-like protein-1 (APLP1). Noteworthy, APLP2, but not APLP1, interacts with Stub1 and CRL4(CRBN), pointing to a functional pathway shared only by APP and APLP2. In vitro ubiquitination/ubiquitome analysis indicates that these E3 ligases are enzymatically active and ubiquitinate the ACR residues Lys(649/650/651/676/688) Deletion of Crbn reduces ubiquitination of Lys(676) suggesting that Lys(676) is physiologically ubiquitinated by CRL4(CRBN) The ACR facilitated in vitro ubiquitination of presynaptic proteins that regulate exocytosis, suggesting a mechanism by which APP tunes transmitter release. Other dementia-related proteins, namely Tau and apoE, interact with and are ubiquitinated via the ACR in vitro This, and the evidence that CRBN and CUL4B are linked to intellectual disability, prompts us to hypothesize a pathogenic mechanism, in which APP acts as a modulator of E3 ubiquitin-protein ligase(s), shared by distinct neuronal disorders. The well described accumulation of ubiquitinated protein inclusions in neurodegenerative diseases and the link between the ubiquitin-proteasome system and neurodegeneration make this concept plausible.
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Affiliation(s)
- Dolores Del Prete
- From the Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461 and
| | - Richard C Rice
- the Division of Pediatric Neurology, Department of Pediatrics, and
| | - Anjali M Rajadhyaksha
- the Division of Pediatric Neurology, Department of Pediatrics, and Feil Family Brain and Mind Research Institute, Weill Cornell Autism Research Program, Weill Cornell Medical College, New York, New York 10065
| | - Luciano D'Adamio
- From the Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461 and
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Ribeiro JR, Schorl C, Yano N, Romano N, Kim KK, Singh RK, Moore RG. HE4 promotes collateral resistance to cisplatin and paclitaxel in ovarian cancer cells. J Ovarian Res 2016; 9:28. [PMID: 27184254 PMCID: PMC4869286 DOI: 10.1186/s13048-016-0240-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 05/05/2016] [Indexed: 01/09/2023] Open
Abstract
Background Chemotherapy resistance presents a difficult challenge in treating epithelial ovarian cancer patients, particularly when tumors exhibit resistance to multiple chemotherapeutic agents. A few studies have shown that elevated serum levels of the ovarian cancer biomarker HE4 correlate with tumor chemoresistance, response to treatment, and survival. Here, we sought to confirm our previous results that HE4 contributes to collateral resistance to cisplatin and paclitaxel in vitro and uncover factors that may contribute to HE4-mediated chemoresistance. Methods MTS assays and western blots for cleaved PARP were used to assess resistance of HE4-overexpressing SKOV3 and OVCAR8 clones to cisplatin and paclitaxel. CRISPR/Cas technology was used to knockdown HE4 in HE4-overexpressing SKOV3 cells. A microarray was conducted to determine differential gene expression between SKOV3 null vector-transfected and HE4-overexpressing clones upon cisplatin exposure, and results were validated by quantitative RT-PCR. Regulation of mitogen activated protein kinases (MAPKs) and tubulins were assessed by western blot. Results HE4-overexpressing SKOV3 and OVCAR8 clones displayed increased resistance to cisplatin and paclitaxel. Knockdown of HE4 in HE4-overexpressing SKOV3 cells partially reversed chemoresistance. Microarray analysis revealed that HE4 overexpression resulted in suppression of cisplatin-mediated upregulation of EGR1, a MAPK-regulated gene involved in promoting apoptosis. Upregulation of p38, a MAPK activated in response to cisplatin, was suppressed in HE4-overexpressing clones. No differences in extracellular signal-regulated kinase (ERK) activation were noted in HE4-overexpressing clones treated with 25 μM cisplatin, but ERK activation was partially suppressed in HE4-overexpressing clones treated with 80 μM cisplatin. Furthermore, treatment of cells with recombinant HE4 dramatically affected ERK activation in SKOV3 and OVCAR8 wild type cells. Recombinant HE4 also upregulated α-tubulin and β-tubulin levels in SKOV3 and OVCAR8 cells, and microtubule associated protein tau (MAPT) gene expression was increased in SKOV3 HE4-overexpressing clones. Conclusions Overexpression of HE4 promotes collateral resistance to cisplatin and paclitaxel, and downregulation of HE4 partially reverses this chemoresistance. Multiple factors could be involved in HE4-mediated chemoresistance, including deregulation of MAPK signaling, as well as alterations in tubulin levels or stability. Electronic supplementary material The online version of this article (doi:10.1186/s13048-016-0240-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- J R Ribeiro
- Women and Infants Hospital, Department of Obstetrics and Gynecology, Program in Women's Oncology, Molecular Therapeutics Laboratory, 200 Chestnut Street, Providence, RI, 02903, USA.
| | - C Schorl
- Center for Genomics and Proteomics, Genomics Core Facility, Brown University, 70 Ship Street, Providence, RI, 02903, USA
| | - N Yano
- Women and Infants Hospital, Department of Obstetrics and Gynecology, Program in Women's Oncology, Molecular Therapeutics Laboratory, 200 Chestnut Street, Providence, RI, 02903, USA
| | - N Romano
- Women and Infants Hospital, Department of Obstetrics and Gynecology, Program in Women's Oncology, Molecular Therapeutics Laboratory, 200 Chestnut Street, Providence, RI, 02903, USA
| | - K K Kim
- Wilmot Cancer Institute, Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Rochester Medical Center, Rochester, NY, USA
| | - R K Singh
- Women and Infants Hospital, Department of Obstetrics and Gynecology, Program in Women's Oncology, Molecular Therapeutics Laboratory, 200 Chestnut Street, Providence, RI, 02903, USA.,Wilmot Cancer Institute, Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Rochester Medical Center, Rochester, NY, USA
| | - R G Moore
- Women and Infants Hospital, Department of Obstetrics and Gynecology, Program in Women's Oncology, Molecular Therapeutics Laboratory, 200 Chestnut Street, Providence, RI, 02903, USA.,Wilmot Cancer Institute, Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Rochester Medical Center, Rochester, NY, USA
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