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Biadun M, Sochacka M, Kalka M, Chorazewska A, Karelus R, Krowarsch D, Opalinski L, Zakrzewska M. Uncovering key steps in FGF12 cellular release reveals a common mechanism for unconventional FGF protein secretion. Cell Mol Life Sci 2024; 81:356. [PMID: 39158730 PMCID: PMC11335280 DOI: 10.1007/s00018-024-05396-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 08/03/2024] [Accepted: 08/04/2024] [Indexed: 08/20/2024]
Abstract
FGF12 belongs to a subfamily of FGF proteins called FGF homologous factors (FHFs), which until recently were thought to be non-signaling intracellular proteins. Our recent studies have shown that although they lack a conventional signal peptide for secretion, they can reach the extracellular space, especially under stress conditions. Here, we unraveled that the long "a" isoform of FGF12 is secreted in a pathway involving the A1 subunit of Na(+)/K(+) ATPase (ATP1A1), Tec kinase and lipids such as phosphatidylinositol and phosphatidylserine. Further, we showed that the short "b" isoform of FGF12, which binds ATP1A1 and phosphatidylserine less efficiently, is not secreted from cells. We also indicated regions in the FGF12a protein sequence that are crucial for its secretion, including N-terminal fragment and specific residues, and proposed that liquid-liquid phase separation may be important in this process. Our results strongly suggest that the mechanism of this process is very similar for all unconventionally secreted FGF proteins.
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Affiliation(s)
- Martyna Biadun
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Martyna Sochacka
- Department of Protein Biotechnology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Marta Kalka
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Aleksandra Chorazewska
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Radoslaw Karelus
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Daniel Krowarsch
- Department of Protein Biotechnology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Lukasz Opalinski
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Malgorzata Zakrzewska
- Department of Protein Engineering, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, 50-383, Poland.
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2
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Kim DK, Suh K, Park J, Lee SE, Han J, Chang S, Kim Y, Mook-Jung I. FGFR3 drives Aβ-induced tau uptake. Exp Mol Med 2024; 56:1631-1642. [PMID: 38951140 PMCID: PMC11297141 DOI: 10.1038/s12276-024-01274-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 07/03/2024] Open
Abstract
The amyloid cascade hypothesis suggests that amyloid beta (Aβ) contributes to initiating subsequent tau pathology in Alzheimer's disease (AD). However, the underlying mechanisms through which Aβ contributes to tau uptake and propagation remain poorly understood. Here, we show that preexisting amyloid pathology accelerates the uptake of extracellular tau into neurons. Using quantitative proteomic analysis of endocytic vesicles, we reveal that Aβ induces the internalization of fibroblast growth factor receptor 3 (FGFR3). Extracellular tau binds to the extracellular domain of FGFR3 and is internalized by the FGFR3 ligand, fibroblast growth factor 2 (FGF2). Aβ accelerates FGF2 secretion from neurons, thereby inducing the internalization of tau-attached FGFR3. Knockdown of FGFR3 in the hippocampus reduces tau aggregation by decreasing tau uptake and improving memory function in AD model mice. These data suggest FGFR3 in neurons as a novel tau receptor and a key mediator of Aβ-induced tau uptake in AD.
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Affiliation(s)
- Dong Kyu Kim
- Department of Biomedical Science, College of Medicine, Seoul National University, Seoul, Korea
- Convergence Research Center for Dementia, Medical Research Center, Seoul National University, Seoul, Korea
| | - Kyujin Suh
- Department of Biomedical Science, College of Medicine, Seoul National University, Seoul, Korea
- Convergence Research Center for Dementia, Medical Research Center, Seoul National University, Seoul, Korea
| | - Junho Park
- Department of Medical Science, CHA University School of Medicine, Seongnam, Republic of Korea
- Advanced Omics Center, Future Medicine Research Institute, CHA Bundang Medical Center, Seongnam, Republic of Korea
| | - Sang-Eun Lee
- Department of Biomedical Science, College of Medicine, Seoul National University, Seoul, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, South Korea
| | - Jihui Han
- Department of Biomedical Science, College of Medicine, Seoul National University, Seoul, Korea
- Convergence Research Center for Dementia, Medical Research Center, Seoul National University, Seoul, Korea
| | - Sunghoe Chang
- Department of Biomedical Science, College of Medicine, Seoul National University, Seoul, Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, South Korea
| | - Youngsoo Kim
- Department of Medical Science, CHA University School of Medicine, Seongnam, Republic of Korea
- Advanced Omics Center, Future Medicine Research Institute, CHA Bundang Medical Center, Seongnam, Republic of Korea
| | - Inhee Mook-Jung
- Department of Biomedical Science, College of Medicine, Seoul National University, Seoul, Korea.
- Convergence Research Center for Dementia, Medical Research Center, Seoul National University, Seoul, Korea.
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3
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Sun Y, Islam S, Gao Y, Nakamura T, Tomita T, Michikawa M, Zou K. Presenilin deficiency enhances tau phosphorylation and its secretion. J Neurochem 2024. [PMID: 38946496 DOI: 10.1111/jnc.16155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 05/09/2024] [Accepted: 05/20/2024] [Indexed: 07/02/2024]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of abnormally folded amyloid β-protein (Aβ) in the brain parenchyma and phosphorylated tau in neurons. Presenilin (PS, PSEN) 1 and PS2 are essential components of γ-secretase, which is responsible for the cleavage of amyloid precursor protein (APP) to generate Aβ. PSEN mutations are associated with tau aggregation in frontotemporal dementia, regardless of the presence or absence of Aβ pathology. However, the mechanism by which PS regulates tau aggregation is still unknown. Here, we found that tau phosphorylation and secretion were significantly increased in PS double-knock-out (PS1/2-/-) fibroblasts compared with wild-type fibroblasts. Tau-positive vesicles in the cytoplasm were significantly increased in PS1/2-/- fibroblasts. Active GSK-3β was increased in PS1/2-/- fibroblasts, and inhibiting GSK3β activity in PS1/2-/- fibroblasts resulted in decreased tau phosphorylation and secretion. Transfection of WT human PS1 and PS2 reduced the secretion of phosphorylated tau and active GSK-3β in PS1/2-/- fibroblasts. However, PS1D257A without γ-secretase activity did not decrease the secretion of phosphorylated tau. Furthermore, nicastrin deficiency also increased tau phosphorylation and secretion. These results suggest that deficient PS complex maturation may increase tau phosphorylation and secretion. Thus, our studies discover a new pathway by which PS regulates tau phosphorylation/secretion and pathology independent of Aβ and suggest that PS serves as a potential therapeutic target for treating neurodegenerative diseases involving tau aggregation.
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Affiliation(s)
- Yang Sun
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Sadequl Islam
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Yuan Gao
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Tomohisa Nakamura
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Taisuke Tomita
- Laboratory of Neuropathology and Neuroscience, Faculty of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Makoto Michikawa
- Department of Geriatric Medicine, School of Life Dentistry at Niigata, The Nippon Dental University, Niigata, Japan
| | - Kun Zou
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
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4
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Sindi G, Ismael S, Uddin R, Slepchenko KG, Colvin RA, Lee D. Endogenous tau released from human ReNCell VM cultures by neuronal activity is phosphorylated at multiple sites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.02.597022. [PMID: 38854111 PMCID: PMC11160771 DOI: 10.1101/2024.06.02.597022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Tau is an intracellular protein but also known to be released into the extracellular fluid. Tau release mechanisms have drawn intense attention as these are known to play a key role in Alzheimer's disease (AD) pathology. However, tau can also be released under physiological conditions although its physiological function and release mechanisms have been poorly characterized, especially in human neuronal cells. We investigated endogenous tau release in ReNCell VM, a human neuroprogenitor cell line, under physiological conditions and found that tau is spontaneously released from cells. To study activity-dependent release of endogenous tau, human ReNCell VM culture was stimulated by 100μM AMPA or 50mM KCl for one-hour, tau was actively released to the culture medium. The released tau was highly phosphorylated at nine phosphorylation sites (pSites) detected by phospho-specific tau antibodies including AT270 (T175/T181), AT8 (S202/T205), AT100 (T212/S214), AT180 (T231), and PHF-1 (S396/S404), showing that these pSites are important for activity-dependent tau release from human ReNCell VM. Intracellular tau showed various phosphorylation status across these sites, with AT270 and PHF-1 highly phosphorylated while AT8 and AT180 were minimally phosphorylated, suggesting that AT8 and AT180 pSites exhibit a propensity for secretion rather than being retained intracellularly. This activity-dependent tau release was significantly decreased by inhibition of GSK-3β, demonstrating that GSK3β-dependent phosphorylation of tau plays an important role in its release by neuronal activity. In this study, we showed that ReNCell VM serves as a valuable model for studying endogenous physiological tau release. Further, ReNCell model can be also used to study pathological release of human tau that will contribute to our understanding of the progression of AD and related dementias.
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Affiliation(s)
| | - Sazan Ismael
- Neuroscience Program, Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Reaz Uddin
- Neuroscience Program, Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Kira G. Slepchenko
- Neuroscience Program, Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Robert A. Colvin
- Neuroscience Program, Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Daewoo Lee
- Neuroscience Program, Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
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5
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Canet G, Monteiro FDG, Rocaboy E, Diego-Diaz S, Khelaifia B, Kim J, Valencia D, Yin A, Wu HT, Howell J, Blank E, Laliberté F, Fortin N, Boscher E, Fereydouni-Forouzandeh P, Champagne S, Guisle I, Hébert S, Pernet V, Liu H, Lu W, Debure L, Rapoport D, Ayappa I, Varga A, Parekh A, Osorio R, Lacroix S, Lucey B, Blessing E, Planel E. Sleep-wake body temperature regulates tau secretion in mice and correlates with CSF and plasma tau in humans. RESEARCH SQUARE 2024:rs.3.rs-4384494. [PMID: 38798432 PMCID: PMC11118695 DOI: 10.21203/rs.3.rs-4384494/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The sleep-wake cycle regulates interstitial fluid and cerebrospinal fluid (CSF) tau levels in both mouse and human by mechanisms that remain unestablished. Here, we reveal a novel pathway by which wakefulness increases extracellular tau levels in mouse and humans. In mice, higher body temperature (BT) associated with wakefulness and sleep deprivation increased CSF tau. In vitro, wakefulness temperatures upregulated tau secretion via a temperature-dependent increase in activity and expression of unconventional protein secretion pathway-1 components, namely caspase-3-mediated C-terminal cleavage of tau (TauC3), and membrane expression of PIP2 and syndecan-3. In humans, the increase in both CSF and plasma tau levels observed post-wakefulness correlated with BT increase during wakefulness. Our findings suggest sleep-wake variation in BT may contribute to regulating extracellular tau levels, highlighting the importance of thermoregulation in pathways linking sleep disturbance to neurodegeneration, and the potential for thermal intervention to prevent or delay tau-mediated neurodegeneration.
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Affiliation(s)
| | | | - Emma Rocaboy
- Research Center of CHU de Quebec - Laval University
| | | | | | - Jessica Kim
- Department of Psychiatry, NYU Grossman School of Medicine
| | - Daphne Valencia
- Mount Sinai Integrative Sleep Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai
| | - Audrey Yin
- Department of Psychiatry, NYU Grossman School of Medicine
| | - Hau-Tieng Wu
- Department of Psychiatry, NYU Grossman School of Medicine
| | - Jordan Howell
- Department of Psychiatry, NYU Grossman School of Medicine
| | - Emily Blank
- Department of Psychiatry, NYU Grossman School of Medicine
| | | | - Nadia Fortin
- Research Center of CHU de Quebec - Laval University
| | - Emmanuelle Boscher
- Centre de recherche du CHU de Québec-Université Laval, CHUL, Axe Neurosciences, Faculté de médecine, Département de psychiatrie et de neurosciences, Québec, C
| | | | | | | | - Sébastien Hébert
- Centre de recherche du CHU de Québec - Université Laval, Axe neurosciences, Québec
| | | | | | - William Lu
- Department of Neurology, Washington University School of Medicine
| | | | - David Rapoport
- Mount Sinai Integrative Sleep Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai
| | - Indu Ayappa
- Mount Sinai Integrative Sleep Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai
| | - Andrew Varga
- Mount Sinai Integrative Sleep Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai
| | - Ankit Parekh
- Mount Sinai Integrative Sleep Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai
| | | | | | - Brendan Lucey
- Department of Neurology, Washington University School of Medicine
| | | | - Emmanuel Planel
- Centre de recherche du CHU de Québec - Université Laval, Axe neurosciences, Québec
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6
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Tam S, Wear D, Morrone CD, Yu WH. The complexity of extracellular vesicles: Bridging the gap between cellular communication and neuropathology. J Neurochem 2024. [PMID: 38650384 DOI: 10.1111/jnc.16108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 03/12/2024] [Accepted: 03/31/2024] [Indexed: 04/25/2024]
Abstract
Brain-derived extracellular vesicles (EVs) serve a prominent role in maintaining homeostasis and contributing to pathology in health and disease. This review establishes a crucial link between physiological processes leading to EV biogenesis and their impacts on disease. EVs are involved in the clearance and transport of proteins and nucleic acids, responding to changes in cellular processes associated with neurodegeneration, including autophagic disruption, organellar dysfunction, aging, and other cell stresses. In neurodegenerative disorders (e.g., Alzheimer's disease, Parkinson's disease, etc.), EVs contribute to the spread of pathological proteins like amyloid β, tau, ɑ-synuclein, prions, and TDP-43, exacerbating neurodegeneration and accelerating disease progression. Despite evidence for both neuropathological and neuroprotective effects of EVs, the mechanistic switch between their physiological and pathological functions remains elusive, warranting further research into their involvement in neurodegenerative disease. Moreover, owing to their innate ability to traverse the blood-brain barrier and their ubiquitous nature, EVs emerge as promising candidates for novel diagnostic and therapeutic strategies. The review uniquely positions itself at the intersection of EV cell biology, neurophysiology, and neuropathology, offering insights into the diverse biological roles of EVs in health and disease.
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Affiliation(s)
- Stephanie Tam
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Darcy Wear
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Christopher D Morrone
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Wai Haung Yu
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
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7
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Wang L, Xu Y, Fukushige T, Saidi L, Wang X, Yu C, Lee JG, Krause M, Huang L, Ye Y. Mono-UFMylation promotes misfolding-associated secretion of α-synuclein. SCIENCE ADVANCES 2024; 10:eadk2542. [PMID: 38489364 PMCID: PMC10942102 DOI: 10.1126/sciadv.adk2542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 02/12/2024] [Indexed: 03/17/2024]
Abstract
Stressed cells secret misfolded proteins lacking signaling sequence via an unconventional protein secretion (UcPS) pathway, but how misfolded proteins are targeted selectively in UcPS is unclear. Here, we report that misfolded UcPS clients are subject to modification by a ubiquitin-like protein named ubiquitin-fold modifier 1 (UFM1). Using α-synuclein (α-Syn) as a UcPS model, we show that mutating the UFMylation sites in α-Syn or genetic inhibition of the UFMylation system mitigates α-Syn secretion, whereas overexpression of UFBP1, a component of the endoplasmic reticulum-associated UFMylation ligase complex, augments α-Syn secretion in mammalian cells and in model organisms. UFM1 itself is cosecreted with α-Syn, and the serum UFM1 level correlates with that of α-Syn. Because UFM1 can be directly recognized by ubiquitin specific peptidase 19 (USP19), a previously established UcPS stimulator known to associate with several chaperoning activities, UFMylation might facilitate substrate engagement by USP19, allowing stringent and regulated selection of misfolded proteins for secretion and proteotoxic stress alleviation.
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Affiliation(s)
- Lihui Wang
- Laboratory of Molecular Biology, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yue Xu
- Laboratory of Molecular Biology, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tetsunari Fukushige
- Laboratory of Molecular Biology, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Layla Saidi
- Laboratory of Molecular Biology, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xiaorong Wang
- Department of Physiology and Biophysics, University of California Irvine, Irvine, CA 92697, USA
| | - Clinton Yu
- Department of Physiology and Biophysics, University of California Irvine, Irvine, CA 92697, USA
| | - Jin-Gu Lee
- Laboratory of Molecular Biology, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michael Krause
- Laboratory of Molecular Biology, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lan Huang
- Department of Physiology and Biophysics, University of California Irvine, Irvine, CA 92697, USA
| | - Yihong Ye
- Laboratory of Molecular Biology, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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8
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Lolicato F, Steringer JP, Saleppico R, Beyer D, Fernandez-Sobaberas J, Unger S, Klein S, Riegerová P, Wegehingel S, Müller HM, Schmitt XJ, Kaptan S, Freund C, Hof M, Šachl R, Chlanda P, Vattulainen I, Nickel W. Disulfide bridge-dependent dimerization triggers FGF2 membrane translocation into the extracellular space. eLife 2024; 12:RP88579. [PMID: 38252473 PMCID: PMC10945597 DOI: 10.7554/elife.88579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024] Open
Abstract
Fibroblast growth factor 2 (FGF2) exits cells by direct translocation across the plasma membrane, a type I pathway of unconventional protein secretion. This process is initiated by phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2)-dependent formation of highly dynamic FGF2 oligomers at the inner plasma membrane leaflet, inducing the formation of lipidic membrane pores. Cell surface heparan sulfate chains linked to glypican-1 (GPC1) capture FGF2 at the outer plasma membrane leaflet, completing FGF2 membrane translocation into the extracellular space. While the basic steps of this pathway are well understood, the molecular mechanism by which FGF2 oligomerizes on membrane surfaces remains unclear. In the current study, we demonstrate the initial step of this process to depend on C95-C95 disulfide-bridge-mediated FGF2 dimerization on membrane surfaces, producing the building blocks for higher FGF2 oligomers that drive the formation of membrane pores. We find FGF2 with a C95A substitution to be defective in oligomerization, pore formation, and membrane translocation. Consistently, we demonstrate a C95A variant of FGF2 to be characterized by a severe secretion phenotype. By contrast, while also important for efficient FGF2 secretion from cells, a second cysteine residue on the molecular surface of FGF2 (C77) is not involved in FGF2 oligomerization. Rather, we find C77 to be part of the interaction interface through which FGF2 binds to the α1 subunit of the Na,K-ATPase, the landing platform for FGF2 at the inner plasma membrane leaflet. Using cross-linking mass spectrometry, atomistic molecular dynamics simulations combined with a machine learning analysis and cryo-electron tomography, we propose a mechanism by which disulfide-bridged FGF2 dimers bind with high avidity to PI(4,5)P2 on membrane surfaces. We further propose a tight coupling between FGF2 secretion and the formation of ternary signaling complexes on cell surfaces, hypothesizing that C95-C95-bridged FGF2 dimers are functioning as the molecular units triggering autocrine and paracrine FGF2 signaling.
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Affiliation(s)
- Fabio Lolicato
- Heidelberg University Biochemistry CenterHeidelbergGermany
- Department of Physics, University of HelsinkiHelsinkiFinland
| | | | | | - Daniel Beyer
- Heidelberg University Biochemistry CenterHeidelbergGermany
| | | | | | - Steffen Klein
- Schaller Research Group, Department of Infectious Diseases-Virology, Heidelberg University HospitalHeidelbergGermany
| | - Petra Riegerová
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of SciencesPragueCzech Republic
| | | | | | - Xiao J Schmitt
- Institute for Chemistry and Biochemistry, Freie Universität BerlinBerlinGermany
| | - Shreyas Kaptan
- Department of Physics, University of HelsinkiHelsinkiFinland
| | - Christian Freund
- Institute for Chemistry and Biochemistry, Freie Universität BerlinBerlinGermany
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of SciencesPragueCzech Republic
| | - Radek Šachl
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of SciencesPragueCzech Republic
| | - Petr Chlanda
- Schaller Research Group, Department of Infectious Diseases-Virology, Heidelberg University HospitalHeidelbergGermany
| | | | - Walter Nickel
- Heidelberg University Biochemistry CenterHeidelbergGermany
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9
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Yu Q, Du F, Belli I, Gomes PA, Sotiropoulos I, Waites CL. Glucocorticoid stress hormones stimulate vesicle-free Tau secretion and spreading in the brain. Cell Death Dis 2024; 15:73. [PMID: 38238309 PMCID: PMC10796385 DOI: 10.1038/s41419-024-06458-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 01/22/2024]
Abstract
Chronic stress and elevated levels of glucocorticoids (GCs), the main stress hormones, accelerate Alzheimer's disease (AD) onset and progression. A major driver of AD progression is the spreading of pathogenic Tau protein between brain regions, precipitated by neuronal Tau secretion. While stress and high GC levels are known to induce intraneuronal Tau pathology (i.e. hyperphosphorylation, oligomerization) in animal models, their role in trans-neuronal Tau spreading is unexplored. Here, we find that GCs promote secretion of full-length, primarily vesicle-free, phosphorylated Tau from murine hippocampal neurons and ex vivo brain slices. This process requires neuronal activity and the kinase GSK3β. GCs also dramatically enhance trans-neuronal Tau spreading in vivo, and this effect is blocked by an inhibitor of Tau oligomerization and type 1 unconventional protein secretion. These findings uncover a potential mechanism by which stress/GCs stimulate Tau propagation in AD.
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Affiliation(s)
- Qing Yu
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and Aging Brain, Columbia University Irving Medical Center, New York, NY, USA
| | - Fang Du
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and Aging Brain, Columbia University Irving Medical Center, New York, NY, USA
| | - Irla Belli
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and Aging Brain, Columbia University Irving Medical Center, New York, NY, USA
| | - Patricia A Gomes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Ioannis Sotiropoulos
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
- Institute of Biosciences and Applications, National Centre for Scientific Research (NCSR) Demokritos, Agia Paraskevi, Greece
| | - Clarissa L Waites
- Department of Pathology and Cell Biology, Taub Institute for Research on Alzheimer's Disease and Aging Brain, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Neuroscience, Columbia University, New York, NY, USA.
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10
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Giusti V, Kaur G, Giusto E, Civiero L. Brain clearance of protein aggregates: a close-up on astrocytes. Mol Neurodegener 2024; 19:5. [PMID: 38229094 DOI: 10.1186/s13024-024-00703-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 01/05/2024] [Indexed: 01/18/2024] Open
Abstract
Protein misfolding and accumulation defines a prevailing feature of many neurodegenerative disorders, finally resulting in the formation of toxic intra- and extracellular aggregates. Intracellular aggregates can enter the extracellular space and be subsequently transferred among different cell types, thus spreading between connected brain districts.Although microglia perform a predominant role in the removal of extracellular aggregated proteins, mounting evidence suggests that astrocytes actively contribute to the clearing process. However, the molecular mechanisms used by astrocytes to remove misfolded proteins are still largely unknown.Here we first provide a brief overview of the progressive transition from soluble monomers to insoluble fibrils that characterizes amyloid proteins, referring to α-Synuclein and Tau as archetypical examples. We then highlight the mechanisms at the basis of astrocyte-mediated clearance with a focus on their potential ability to recognize, collect, internalize and digest extracellular protein aggregates. Finally, we explore the potential of targeting astrocyte-mediated clearance as a future therapeutic approach for the treatment of neurodegenerative disorders characterized by protein misfolding and accumulation.
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Affiliation(s)
| | - Gurkirat Kaur
- Department of Biology, University of Padova, Padua, Italy
| | | | - Laura Civiero
- IRCCS San Camillo Hospital, Venice, Italy.
- Department of Biology, University of Padova, Padua, Italy.
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11
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Hu J, Sha W, Yuan S, Wu J, Huang Y. Aggregation, Transmission, and Toxicity of the Microtubule-Associated Protein Tau: A Complex Comprehension. Int J Mol Sci 2023; 24:15023. [PMID: 37834471 PMCID: PMC10573976 DOI: 10.3390/ijms241915023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/12/2023] [Accepted: 09/18/2023] [Indexed: 10/15/2023] Open
Abstract
The microtubule-associated protein tau is an intrinsically disordered protein containing a few short and transient secondary structures. Tau physiologically associates with microtubules (MTs) for its stabilization and detaches from MTs to regulate its dynamics. Under pathological conditions, tau is abnormally modified, detaches from MTs, and forms protein aggregates in neuronal and glial cells. Tau protein aggregates can be found in a number of devastating neurodegenerative diseases known as "tauopathies", such as Alzheimer's disease (AD), frontotemporal dementia (FTD), corticobasal degeneration (CBD), etc. However, it is still unclear how the tau protein is compacted into ordered protein aggregates, and the toxicity of the aggregates is still debated. Fortunately, there has been considerable progress in the study of tau in recent years, particularly in the understanding of the intercellular transmission of pathological tau species, the structure of tau aggregates, and the conformational change events in the tau polymerization process. In this review, we summarize the concepts of tau protein aggregation and discuss the views on tau protein transmission and toxicity.
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Affiliation(s)
- Jiaxin Hu
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China; (J.H.); (W.S.); (S.Y.)
| | - Wenchi Sha
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China; (J.H.); (W.S.); (S.Y.)
| | - Shuangshuang Yuan
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China; (J.H.); (W.S.); (S.Y.)
| | - Jiarui Wu
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China; (J.H.); (W.S.); (S.Y.)
- Key Laboratory of Systems Biology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Hangzhou 310024, China
| | - Yunpeng Huang
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China; (J.H.); (W.S.); (S.Y.)
- Key Laboratory of Systems Biology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Hangzhou 310024, China
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12
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Le LTHL, Lee J, Im D, Park S, Hwang K, Lee JH, Jiang Y, Lee Y, Suh YH, Kim HI, Lee MJ. Self-Aggregating Tau Fragments Recapitulate Pathologic Phenotypes and Neurotoxicity of Alzheimer's Disease in Mice. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2302035. [PMID: 37594721 PMCID: PMC10582461 DOI: 10.1002/advs.202302035] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 07/10/2023] [Indexed: 08/19/2023]
Abstract
In tauopathy conditions, such as Alzheimer's disease (AD), highly soluble and natively unfolded tau polymerizes into an insoluble filament; however, the mechanistic details of this process remain unclear. In the brains of AD patients, only a minor segment of tau forms β-helix-stacked protofilaments, while its flanking regions form disordered fuzzy coats. Here, it is demonstrated that the tau AD nucleation core (tau-AC) sufficiently induced self-aggregation and recruited full-length tau to filaments. Unexpectedly, phospho-mimetic forms of tau-AC (at Ser324 or Ser356) show markedly reduced oligomerization and seeding propensities. Biophysical analysis reveal that the N-terminus of tau-AC facilitates the fibrillization kinetics as a nucleation motif, which becomes sterically shielded through phosphorylation-induced conformational changes in tau-AC. Tau-AC oligomers are efficiently internalized into cells via endocytosis and induced endogenous tau aggregation. In primary hippocampal neurons, tau-AC impaired axon initial segment plasticity upon chronic depolarization and is mislocalized to the somatodendritic compartments. Furthermore, it is observed significantly impaired memory retrieval in mice intrahippocampally injected with tau-AC fibrils, which corresponds to the neuropathological staining and neuronal loss in the brain. These findings identify tau-AC species as a key neuropathological driver in AD, suggesting novel strategies for therapeutic intervention.
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Affiliation(s)
- Ly Thi Huong Luu Le
- Department of Biochemistry and Molecular BiologySeoul National University College of MedicineSeoul03080South Korea
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
| | - Jeeyoung Lee
- Department of Biochemistry and Molecular BiologySeoul National University College of MedicineSeoul03080South Korea
- Brain Science InstituteKorea Institute of Science and TechnologySeoul02792South Korea
| | - Dongjoon Im
- Department of ChemistryKorea UniversitySeoul02841South Korea
| | - Sunha Park
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
| | - Kyoung‐Doo Hwang
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
- Department of PhysiologySeoul National University College of MedicineSeoul03080South Korea
| | - Jung Hoon Lee
- Department of Biochemistry and Molecular BiologySeoul National University College of MedicineSeoul03080South Korea
| | - Yanxialei Jiang
- Department of Biochemistry and Molecular BiologySeoul National University College of MedicineSeoul03080South Korea
- School of MedicineLinyi UniversityLinyi276000China
| | - Yong‐Seok Lee
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
- Department of PhysiologySeoul National University College of MedicineSeoul03080South Korea
- Neuroscience Research InstituteSeoul National University College of MedicineSeoul03080South Korea
| | - Young Ho Suh
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
- Neuroscience Research InstituteSeoul National University College of MedicineSeoul03080South Korea
| | - Hugh I. Kim
- Department of ChemistryKorea UniversitySeoul02841South Korea
| | - Min Jae Lee
- Department of Biochemistry and Molecular BiologySeoul National University College of MedicineSeoul03080South Korea
- Department of Biomedical SciencesSeoul National University Graduate SchoolSeoul03080South Korea
- Ischemic/Hypoxic Disease Institute, Convergence Research Center for DementiaSeoul National University College of MedicineSeoul03080South Korea
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13
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Waites C, Yu Q, Du F, Belli I, Gomes P, Sotiropoulos I. Glucocorticoid stress hormones stimulate vesicle-free Tau secretion and spreading in the brain. RESEARCH SQUARE 2023:rs.3.rs-3097174. [PMID: 37503224 PMCID: PMC10371092 DOI: 10.21203/rs.3.rs-3097174/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Chronic stress and elevated levels of glucocorticoids (GCs), the main stress hormones, accelerate Alzheimer's disease (AD) onset and progression. A major driver of AD progression is the spreading of pathogenic Tau protein between brain regions, precipitated by neuronal Tau secretion. While stress and high GC levels are known to induce intraneuronal Tau pathology (i.e. hyperphosphorylation, oligomerization) in animal models, their role in trans-neuronal Tau spreading is unexplored. Here, we find that GCs promote secretion of full-length, vesicle-free, phosphorylated Tau from murine hippocampal neurons and ex vivo brain slices. This process occurs via type 1 unconventional protein secretion (UPS) and requires neuronal activity and the kinase GSK3b. GCs also dramatically enhance trans-neuronal Tau spreading in vivo, and this effect is blocked by an inhibitor of Tau oligomerization and type 1 UPS. These findings uncover a potential mechanism by which stress/GCs stimulate Tau propagation in AD.
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Affiliation(s)
| | - Qing Yu
- Columbia University Irving Medical Center
| | - Fang Du
- Columbia University Irving Medical Center
| | - Irla Belli
- Columbia University Irving Medical Center
| | - Patrícia Gomes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
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14
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Yu Q, Du F, Belli I, Gomes PA, Sotiropoulos I, Waites CL. Glucocorticoid stress hormones stimulate vesicle-free Tau secretion and spreading in the brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544054. [PMID: 37333306 PMCID: PMC10274779 DOI: 10.1101/2023.06.07.544054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Chronic stress and elevated levels of glucocorticoids (GCs), the main stress hormones, accelerate Alzheimer's disease (AD) onset and progression. A major driver of AD progression is the spreading of pathogenic Tau protein between brain regions, precipitated by neuronal Tau secretion. While stress and high GC levels are known to induce intraneuronal Tau pathology ( i.e. hyperphosphorylation, oligomerization) in animal models, their role in trans-neuronal Tau spreading is unexplored. Here, we find that GCs promote secretion of full-length, vesicle-free, phosphorylated Tau from murine hippocampal neurons and ex vivo brain slices. This process occurs via type 1 unconventional protein secretion (UPS) and requires neuronal activity and the kinase GSK3β. GCs also dramatically enhance trans-neuronal Tau spreading in vivo , and this effect is blocked by an inhibitor of Tau oligomerization and type 1 UPS. These findings uncover a potential mechanism by which stress/GCs stimulate Tau propagation in AD.
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15
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Jacopo M. Unconventional protein secretion (UPS): role in important diseases. MOLECULAR BIOMEDICINE 2023; 4:2. [PMID: 36622461 PMCID: PMC9827022 DOI: 10.1186/s43556-022-00113-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 12/19/2022] [Indexed: 01/10/2023] Open
Abstract
Unconventional protein secretion (UPS) is the new secretion process discovered in liquid form over three decades ago. More recently, UPS has been shown to operate also in solid forms generated from four types of organelles: fractions of lysosomes and autophagy (APh) undergoing exocytosis; exosomes and ectosomes, with their extracellular vesicles (EVs). Recently many mechanisms and proteins of these solid forms have been shown to depend on UPS. An additional function of UPS is the regulation of diseases, often investigated separately from each other. In the present review, upon short presentation of UPS in healthy cells and organs, interest is focused on the mechanisms and development of diseases. The first reported are neurodegenerations, characterized by distinct properties. Additional diseases, including inflammasomes, inflammatory responses, glial effects and other diseases of various origin, are governed by proteins generated, directly or alternatively, by UPS. The diseases most intensely affected by UPS are various types of cancer, activated in most important processes: growth, proliferation and invasion, relapse, metastatic colonization, vascular leakiness, immunomodulation, chemoresistence. The therapy role of UPS diseases depends largely on exosomes. In addition to affecting neurodegenerative diseases, its special aim is the increased protection against cancer. Its immense relevance is due to intrinsic features, including low immunogenicity, biocompatibility, stability, and crossing of biological barriers. Exosomes, loaded with factors for pharmacological actions and target cell sensitivity, induce protection against various specific cancers. Further expansion of disease therapies is expected in the near future.
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Affiliation(s)
- Meldolesi Jacopo
- grid.18887.3e0000000417581884San Raffaele Institute, Vita-Salute San Raffaele University, Milan, Italy ,CNR Institute of Neuroscience at the Milano-Bicocca University, Milan, Italy
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16
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Corsi A, Bombieri C, Valenti MT, Romanelli MG. Tau Isoforms: Gaining Insight into MAPT Alternative Splicing. Int J Mol Sci 2022; 23:ijms232315383. [PMID: 36499709 PMCID: PMC9735940 DOI: 10.3390/ijms232315383] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/27/2022] [Accepted: 12/04/2022] [Indexed: 12/13/2022] Open
Abstract
Tau microtubule-associated proteins, encoded by the MAPT gene, are mainly expressed in neurons participating in axonal transport and synaptic plasticity. Six major isoforms differentially expressed during cell development and differentiation are translated by alternative splicing of MAPT transcripts. Alterations in the expression of human Tau isoforms and their aggregation have been linked to several neurodegenerative diseases called tauopathies, including Alzheimer's disease, progressive supranuclear palsy, Pick's disease, and frontotemporal dementia with parkinsonism linked to chromosome 17. Great efforts have been dedicated in recent years to shed light on the complex regulatory mechanism of Tau splicing, with a perspective to developing new RNA-based therapies. This review summarizes the most recent contributions to the knowledge of Tau isoform expression and experimental models, highlighting the role of cis-elements and ribonucleoproteins that regulate the alternative splicing of Tau exons.
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17
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Karimi N, Bayram Çatak F, Arslan E, Saghazadeh A, Rezaei N. Tau immunotherapy in Alzheimer’s disease and progressive supranuclear palsy. Int Immunopharmacol 2022; 113:109445. [DOI: 10.1016/j.intimp.2022.109445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 11/06/2022] [Accepted: 11/08/2022] [Indexed: 11/19/2022]
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18
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Zhu Y, Gandy L, Zhang F, Liu J, Wang C, Blair LJ, Linhardt RJ, Wang L. Heparan Sulfate Proteoglycans in Tauopathy. Biomolecules 2022; 12:1792. [PMID: 36551220 PMCID: PMC9776397 DOI: 10.3390/biom12121792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 11/28/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022] Open
Abstract
Tauopathies are a class of neurodegenerative diseases, including Alzheimer's disease, and are characterized by intraneuronal tau inclusion in the brain and the patient's cognitive decline with obscure pathogenesis. Heparan sulfate proteoglycans, a major type of extracellular matrix, have been believed to involve in tauopathies. The heparan sulfate proteoglycans co-deposit with tau in Alzheimer's patient brain, directly bind to tau and modulate tau secretion, internalization, and aggregation. This review summarizes the current understanding of the functions and the modulated molecular pathways of heparan sulfate proteoglycans in tauopathies, as well as the implication of dysregulated heparan sulfate proteoglycan expression in tau pathology and the potential of targeting heparan sulfate proteoglycan-tau interaction as a novel therapeutic option.
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Affiliation(s)
- Yanan Zhu
- Department of Molecular Pharmacology & Physiology, Byrd Alzheimer’s Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Lauren Gandy
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemistry and Chemical Biology, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Fuming Zhang
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemistry and Chemical Biology, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Jian Liu
- Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Chunyu Wang
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemistry and Chemical Biology, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Laura J. Blair
- Department of Molecular Medicine, Byrd Alzheimer’s Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33613, USA
| | - Robert J. Linhardt
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemistry and Chemical Biology, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Lianchun Wang
- Department of Molecular Pharmacology & Physiology, Byrd Alzheimer’s Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
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19
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Lolicato F, Saleppico R, Griffo A, Meyer A, Scollo F, Pokrandt B, Müller HM, Ewers H, Hähl H, Fleury JB, Seemann R, Hof M, Brügger B, Jacobs K, Vattulainen I, Nickel W. Cholesterol promotes clustering of PI(4,5)P2 driving unconventional secretion of FGF2. J Biophys Biochem Cytol 2022; 221:213511. [PMID: 36173379 PMCID: PMC9526255 DOI: 10.1083/jcb.202106123] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/22/2022] [Accepted: 08/30/2022] [Indexed: 11/22/2022] Open
Abstract
FGF2 is a cell survival factor involved in tumor-induced angiogenesis that is secreted through an unconventional secretory pathway based upon direct protein translocation across the plasma membrane. Here, we demonstrate that both PI(4,5)P2-dependent FGF2 recruitment at the inner plasma membrane leaflet and FGF2 membrane translocation into the extracellular space are positively modulated by cholesterol in living cells. We further revealed cholesterol to enhance FGF2 binding to PI(4,5)P2-containing lipid bilayers. Based on extensive atomistic molecular dynamics (MD) simulations and membrane tension experiments, we proposed cholesterol to modulate FGF2 binding to PI(4,5)P2 by (i) increasing head group visibility of PI(4,5)P2 on the membrane surface, (ii) increasing avidity by cholesterol-induced clustering of PI(4,5)P2 molecules triggering FGF2 oligomerization, and (iii) increasing membrane tension facilitating the formation of lipidic membrane pores. Our findings have general implications for phosphoinositide-dependent protein recruitment to membranes and explain the highly selective targeting of FGF2 toward the plasma membrane, the subcellular site of FGF2 membrane translocation during unconventional secretion of FGF2.
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Affiliation(s)
- Fabio Lolicato
- Heidelberg University Biochemistry Center, Heidelberg, Germany.,Department of Physics, University of Helsinki, Helsinki, Finland
| | | | - Alessandra Griffo
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Biophysical Engineering Group, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Annalena Meyer
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Federica Scollo
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Bianca Pokrandt
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | | | - Helge Ewers
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Hendrik Hähl
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany
| | | | - Ralf Seemann
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Martin Hof
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Britta Brügger
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Karin Jacobs
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Max Planck School Matter to Life, Heidelberg, Germany
| | - Ilpo Vattulainen
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Heidelberg, Germany
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20
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Noh SH, Kim YJ, Lee MG. Autophagy-Related Pathways in Vesicular Unconventional Protein Secretion. Front Cell Dev Biol 2022; 10:892450. [PMID: 35774225 PMCID: PMC9237382 DOI: 10.3389/fcell.2022.892450] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/26/2022] [Indexed: 12/14/2022] Open
Abstract
Cellular proteins directed to the plasma membrane or released into the extracellular space can undergo a number of different pathways. Whereas the molecular mechanisms that underlie conventional ER-to-Golgi trafficking are well established, those associated with the unconventional protein secretion (UPS) pathways remain largely elusive. A pathway with an emerging role in UPS is autophagy. Although originally known as a degradative process for maintaining intracellular homeostasis, recent studies suggest that autophagy has diverse biological roles besides its disposal function and that it is mechanistically involved in the UPS of various secretory cargos including both leaderless soluble and Golgi-bypassing transmembrane proteins. Here, we summarize current knowledge of the autophagy-related UPS pathways, describing and comparing diverse features in the autophagy-related UPS cargos and autophagy machineries utilized in UPS. Additionally, we also suggest potential directions that further research in this field can take.
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Affiliation(s)
- Shin Hye Noh
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Ye Jin Kim
- Department of Pharmacology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
| | - Min Goo Lee
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, South Korea
- Department of Pharmacology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
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21
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Maricchiolo E, Panfili E, Pompa A, De Marchis F, Bellucci M, Pallotta MT. Unconventional Pathways of Protein Secretion: Mammals vs. Plants. Front Cell Dev Biol 2022; 10:895853. [PMID: 35573696 PMCID: PMC9096121 DOI: 10.3389/fcell.2022.895853] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/13/2022] [Indexed: 01/08/2023] Open
Abstract
In eukaryotes, many proteins contain an N-terminal signal peptide that allows their translocation into the endoplasmic reticulum followed by secretion outside the cell according to the classical secretory system. However, an increasing number of secreted proteins lacking the signal peptide sequence are emerging. These proteins, secreted in several alternative ways collectively known as unconventional protein secretion (UPS) pathways, exert extracellular functions including cell signaling, immune modulation, as well as moonlighting activities different from their well-described intracellular functions. Pathways for UPS include direct transfer across the plasma membrane, secretion from endosomal/multivesicular body-related components, release within plasma membrane-derived microvesicles, or use of elements of autophagy. In this review we describe the mammals and plants UPS pathways identified so far highlighting commonalities and differences.
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Affiliation(s)
- Elisa Maricchiolo
- Section of Biological and Biotechnological Sciences, Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Eleonora Panfili
- Section of Pharmacology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Andrea Pompa
- Section of Biological and Biotechnological Sciences, Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Francesca De Marchis
- Institute of Biosciences and Bioresources, National Research Council of Italy, Perugia, Italy
| | - Michele Bellucci
- Institute of Biosciences and Bioresources, National Research Council of Italy, Perugia, Italy
- *Correspondence: Michele Bellucci, ; Maria Teresa Pallotta,
| | - Maria Teresa Pallotta
- Section of Pharmacology, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
- *Correspondence: Michele Bellucci, ; Maria Teresa Pallotta,
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22
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Unconventional secretion mediated by direct protein self-translocation across the plasma membranes of mammalian cells. Trends Biochem Sci 2022; 47:699-709. [PMID: 35490075 DOI: 10.1016/j.tibs.2022.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/22/2022] [Accepted: 04/01/2022] [Indexed: 12/17/2022]
Abstract
In recent years, a surprisingly complex picture emerged about endoplasmic reticulum (ER)/Golgi-independent secretory pathways, and several routes have been discovered that differ with regard to their molecular mechanisms and machineries. Fibroblast growth factor 2 (FGF2) is secreted by a pathway of unconventional protein secretion (UPS) that is based on direct self-translocation across the plasma membrane. Building on previous research, a component of this process has been identified to be glypican-1 (GPC1), a GPI-anchored heparan sulfate proteoglycan located on cell surfaces. These findings not only shed light on the molecular mechanism underlying this process but also reveal an intimate relationship between FGF2 and GPC1 that might be of critical relevance for the prominent roles they both have in tumor progression and metastasis.
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23
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Boyarko B, Hook V. Human Tau Isoforms and Proteolysis for Production of Toxic Tau Fragments in Neurodegeneration. Front Neurosci 2021; 15:702788. [PMID: 34744602 PMCID: PMC8566764 DOI: 10.3389/fnins.2021.702788] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 09/09/2021] [Indexed: 01/27/2023] Open
Abstract
The human tau protein is implicated in a wide range of neurodegenerative “tauopathy” diseases, consisting of Alzheimer’s disease (AD) and frontotemporal lobar degeneration which includes progressive supranuclear palsy, corticobasal degeneration, Pick’s disease, and FTLD-tau (frontotemporal dementia with parkinsonism caused by MAPT mutations). Tau gene transcripts in the human brain undergo alternative splicing to yield 6 different tau protein isoforms that are expressed in different ratios in neurodegeneration which result in tau pathology of paired-helical filaments, neurofibrillary tangles, and tau fibrillar aggregates with detrimental microtubule destabilization. Protease-mediated tau truncation is an important post-translational modification (PTM) which drives neurodegeneration in a tau fragment-dependent manner. While numerous tau fragments have been identified, knowledge of the proteolytic steps that convert each parent tau isoform into specific truncated tau fragments has not yet been fully defined. An improved understanding of the relationships between tau isoforms and their proteolytic processing to generate neurotoxic tau fragments is important to the field. This review evaluates tau isoform expression patterns including PTMs and mutations that influence proteolysis of tau to generate toxic fragments that drive cognitive deficits in AD and other tauopathy models. This assessment identifies the gap in the field on understanding the details of proteolytic steps used to convert each tau isoform into fragments. Knowledge of the processing mechanisms of tau isoforms can lead to new protease targeted drug strategies to prevent the formation of toxic tau fragments in tauopathy neurodegenerative diseases.
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Affiliation(s)
- Ben Boyarko
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, United States.,Department of Neurosciences and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA, United States
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24
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Ismael S, Sindi G, Colvin RA, Lee D. Activity-dependent release of phosphorylated human tau from Drosophila neurons in primary culture. J Biol Chem 2021; 297:101108. [PMID: 34473990 PMCID: PMC8455371 DOI: 10.1016/j.jbc.2021.101108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 08/11/2021] [Accepted: 08/19/2021] [Indexed: 11/23/2022] Open
Abstract
Neuronal activity can enhance tau release and thus accelerate tauopathies. This activity-dependent tau release can be used to study the progression of tau pathology in Alzheimer's disease (AD), as hyperphosphorylated tau is implicated in AD pathogenesis and related tauopathies. However, our understanding of the mechanisms that regulate activity-dependent tau release from neurons and the role that tau phosphorylation plays in modulating activity-dependent tau release is still rudimentary. In this study, Drosophila neurons in primary culture expressing human tau (hTau) were used to study activity-dependent tau release. We found that hTau release was markedly increased by 50 mM KCl treatment for 1 h. A similar level of release was observed using optogenetic techniques, where genetically targeted neurons were stimulated for 30 min using blue light (470 nm). Our results showed that activity-dependent release of phosphoresistant hTauS11A was reduced when compared with wildtype hTau. In contrast, release of phosphomimetic hTauE14 was increased upon activation. We found that released hTau was phosphorylated in its proline-rich and C-terminal domains using phosphorylation site-specific tau antibodies (e.g., AT8). Fold changes in detectable levels of total or phosphorylated hTau in cell lysates or following immunopurification from conditioned media were consistent with preferential release of phosphorylated hTau after light stimulation. This study establishes an excellent model to investigate the mechanism of activity-dependent hTau release and to better understand the role of phosphorylated tau release in the pathogenesis of AD since it relates to alterations in the early stage of neurodegeneration associated with increased neuronal activity.
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Affiliation(s)
- Sazan Ismael
- Neuroscience Program, Department of Biological Sciences, and Molecular and Cellular Biology Interdisciplinary Graduate Program, Ohio University, Athens, Ohio, USA
| | - Ghadir Sindi
- Neuroscience Program, Department of Biological Sciences, and Molecular and Cellular Biology Interdisciplinary Graduate Program, Ohio University, Athens, Ohio, USA
| | - Robert A Colvin
- Neuroscience Program, Department of Biological Sciences, and Molecular and Cellular Biology Interdisciplinary Graduate Program, Ohio University, Athens, Ohio, USA
| | - Daewoo Lee
- Neuroscience Program, Department of Biological Sciences, and Molecular and Cellular Biology Interdisciplinary Graduate Program, Ohio University, Athens, Ohio, USA.
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Ledreux A, Thomas S, Hamlett ED, Trautman C, Gilmore A, Rickman Hager E, Paredes DA, Margittai M, Fortea J, Granholm AC. Small Neuron-Derived Extracellular Vesicles from Individuals with Down Syndrome Propagate Tau Pathology in the Wildtype Mouse Brain. J Clin Med 2021; 10:3931. [PMID: 34501378 PMCID: PMC8432237 DOI: 10.3390/jcm10173931] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 08/24/2021] [Accepted: 08/28/2021] [Indexed: 12/11/2022] Open
Abstract
Individuals with Down syndrome (DS) exhibit Alzheimer's disease (AD) pathology at a young age, including amyloid plaques and neurofibrillary tangles (NFTs). Tau pathology can spread via extracellular vesicles, such as exosomes. The cargo of neuron-derived small extracellular vesicles (NDEVs) from individuals with DS contains p-Tau at an early age. The goal of the study was to investigate whether NDEVs isolated from the blood of individuals with DS can spread Tau pathology in the brain of wildtype mice. We purified NDEVs from the plasma of patients with DS-AD and controls and injected small quantities using stereotaxic surgery into the dorsal hippocampus of adult wildtype mice. Seeding competent Tau conformers were amplified in vitro from DS-AD NDEVs but not NDEVs from controls. One month or 4 months post-injection, we examined Tau pathology in mouse brains. We found abundant p-Tau immunostaining in the hippocampus of the mice injected with DS-AD NDEVs compared to injections of age-matched control NDEVs. Double labeling with neuronal and glial markers showed that p-Tau staining was largely found in neurons and, to a lesser extent, in glial cells and that p-Tau immunostaining was spreading along the corpus callosum and the medio-lateral axis of the hippocampus. These studies demonstrate that NDEVs from DS-AD patients exhibit Tau seeding capacity and give rise to tangle-like intracellular inclusions.
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Affiliation(s)
- Aurélie Ledreux
- Knoebel Institute for Healthy Aging, University of Denver, Denver, CO 80208, USA; (S.T.); (C.T.); (A.G.); (D.A.P.); (A.-C.G.)
| | - Sarah Thomas
- Knoebel Institute for Healthy Aging, University of Denver, Denver, CO 80208, USA; (S.T.); (C.T.); (A.G.); (D.A.P.); (A.-C.G.)
| | - Eric D. Hamlett
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29425, USA;
| | - Camille Trautman
- Knoebel Institute for Healthy Aging, University of Denver, Denver, CO 80208, USA; (S.T.); (C.T.); (A.G.); (D.A.P.); (A.-C.G.)
| | - Anah Gilmore
- Knoebel Institute for Healthy Aging, University of Denver, Denver, CO 80208, USA; (S.T.); (C.T.); (A.G.); (D.A.P.); (A.-C.G.)
| | - Emily Rickman Hager
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA; (E.R.H.); (M.M.)
| | - Daniel A. Paredes
- Knoebel Institute for Healthy Aging, University of Denver, Denver, CO 80208, USA; (S.T.); (C.T.); (A.G.); (D.A.P.); (A.-C.G.)
| | - Martin Margittai
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO 80208, USA; (E.R.H.); (M.M.)
| | - Juan Fortea
- Hospital de la Santa Creu i Sant Pau and Catalan Down Syndrome Foundation, 08041 Barcelona, Spain;
| | - Ann-Charlotte Granholm
- Knoebel Institute for Healthy Aging, University of Denver, Denver, CO 80208, USA; (S.T.); (C.T.); (A.G.); (D.A.P.); (A.-C.G.)
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Membrane interaction and disulphide-bridge formation in the unconventional secretion of Tau. Biosci Rep 2021; 41:229358. [PMID: 34308969 PMCID: PMC8350431 DOI: 10.1042/bsr20210148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 07/04/2021] [Accepted: 07/21/2021] [Indexed: 11/17/2022] Open
Abstract
Misfolded, pathological tau protein propagates from cell to cell causing neuronal degeneration in Alzheimer's disease and other tauopathies. The molecular mechanisms of this process have remained elusive. Unconventional secretion of tau takes place via several different routes, including direct penetration through the plasma membrane. Here, we show that tau secretion requires membrane interaction via disulphide bridge formation. Mutating residues that reduce tau interaction with membranes or formation of disulphide bridges decrease both tau secretion from cells, and penetration through artificial lipid membranes. Our results demonstrate that tau is indeed able to penetrate protein-free membranes in a process independent of active cellular processes and that both membrane interaction and disulphide bridge formation are needed for this process. QUARK-based de novo modelling of the second and third microtubule-binding repeat domains (MTBDs), in which the two cysteine residues of 4R isoforms of tau are located, supports the concept that this region of tau could form transient amphipathic helices for membrane interaction.
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27
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Wei Y, Liu M, Wang D. The propagation mechanisms of extracellular tau in Alzheimer's disease. J Neurol 2021; 269:1164-1181. [PMID: 33913022 DOI: 10.1007/s00415-021-10573-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 01/07/2023]
Abstract
Tubulin-associated unit (tau) is an important microtubule-associated protein. The abnormal intracellular aggregation of tau has been strongly associated with Alzheimer's disease (AD). Accumulating evidence has conclusively demonstrated that tau is present in the cytoplasm of neurons and is also actively released into the extracellular space. However, the types of tau species that are released are unclear, as is the mechanism of their release by donor neurons and subsequent uptake by recipient neurons in AD. Understanding the underlying mechanisms of abnormal tau cell-to-cell transmission can provide novel insights into the etiology and pathogenesis of AD and can help identify new targets for the development of AD therapies focused on counteracting neurodegeneration or even preventing it. From this perspective, the present review focuses on recent advances in understanding the mechanisms regulating the levels of extracellular tau and discusses the role of such mechanisms in the propagation of tau-associated pathology.
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Affiliation(s)
- Yun Wei
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing city, 100091, China.
| | - Meixia Liu
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing city, 100091, China
| | - Dongxin Wang
- Jining Hospital of Integrated Traditional Chinese Medicine and Western Medicine, Shandong province, 272000, China
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Houben S, Homa M, Yilmaz Z, Leroy K, Brion JP, Ando K. Tau Pathology and Adult Hippocampal Neurogenesis: What Tau Mouse Models Tell us? Front Neurol 2021; 12:610330. [PMID: 33643196 PMCID: PMC7902892 DOI: 10.3389/fneur.2021.610330] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/06/2021] [Indexed: 12/18/2022] Open
Abstract
Adult hippocampal neurogenesis (AHN) has been widely confirmed in mammalian brains. A growing body of evidence points to the fact that AHN sustains hippocampal-dependent functions such as learning and memory. Impaired AHN has been reported in post-mortem human brain hippocampus of Alzheimer's disease (AD) and is considered to contribute to defects in learning and memory. Neurofibrillary tangles (NFTs) and amyloid plaques are the two key neuropathological hallmarks of AD. NFTs are composed of abnormal tau proteins accumulating in many brain areas during the progression of the disease, including in the hippocampus. The physiological role of tau and impact of tau pathology on AHN is still poorly understood. Modifications in AHN have also been reported in some tau transgenic and tau-deleted mouse models. We present here a brief review of advances in the relationship between development of tau pathology and AHN in AD and what insights have been gained from studies in tau mouse models.
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Affiliation(s)
- Sarah Houben
- Laboratory of Histology, Neuroanatomy and Neuropathology, UNI (ULB Neuroscience Institute), Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Mégane Homa
- Laboratory of Histology, Neuroanatomy and Neuropathology, UNI (ULB Neuroscience Institute), Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Zehra Yilmaz
- Laboratory of Histology, Neuroanatomy and Neuropathology, UNI (ULB Neuroscience Institute), Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Karelle Leroy
- Laboratory of Histology, Neuroanatomy and Neuropathology, UNI (ULB Neuroscience Institute), Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Jean-Pierre Brion
- Laboratory of Histology, Neuroanatomy and Neuropathology, UNI (ULB Neuroscience Institute), Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Kunie Ando
- Laboratory of Histology, Neuroanatomy and Neuropathology, UNI (ULB Neuroscience Institute), Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
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Lo CH, Sachs JN. The role of wild-type tau in Alzheimer's disease and related tauopathies. JOURNAL OF LIFE SCIENCES (WESTLAKE VILLAGE, CALIF.) 2020; 2:1-17. [PMID: 33665646 PMCID: PMC7929479 DOI: 10.36069/jols/20201201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Tau oligomers have recently emerged as the principal toxic species in Alzheimer's disease (AD) and tauopathies. Tau oligomers are spontaneously self-assembled soluble tau proteins that are formed prior to fibrils, and they have been shown to play a central role in neuronal cell death and in the induction of neurodegeneration in animal models. As the therapeutic paradigm shifts to targeting toxic tau oligomers, this suggests the focus to study tau oligomerization in species that are less susceptible to fibrillization. While truncated and mutation containing tau as well as the isolated repeat domains are particularly prone to fibrillization, the wild-type (WT) tau proteins have been shown to be resistant to fibril formation in the absence of aggregation inducers. In this review, we will summarize and discuss the toxicity of WT tau both in vitro and in vivo, as well as its involvement in tau oligomerization and cell-to-cell propagation of pathology. Understanding the role of WT tau will enable more effective biomarker development and therapeutic discovery for treatment of AD and tauopathies.
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Affiliation(s)
- Chih Hung Lo
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115
| | - Jonathan N. Sachs
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455
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