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  • 1.
    Domert, Jakob
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för neuro- och inflammationsvetenskap. Linköpings universitet, Medicinska fakulteten.
    Sackmann, Christopher
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för neuro- och inflammationsvetenskap. Linköpings universitet, Medicinska fakulteten.
    Severinsson, Emelie
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för neuro- och inflammationsvetenskap. Linköpings universitet, Medicinska fakulteten.
    Agholme, Lotta
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten. University of Gothenburg, Sweden.
    Bergstrom, Joakim
    Uppsala University, Sweden.
    Ingelsson, Martin
    Uppsala University, Sweden.
    Hallbeck, Martin
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för neuro- och inflammationsvetenskap. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Diagnostikcentrum, Klinisk patologi och klinisk genetik.
    Aggregated Alpha-Synuclein Transfer Efficiently between Cultured Human Neuron-Like Cells and Localize to Lysosomes2016Ingår i: PLOS ONE, ISSN 1932-6203, Vol. 11, nr 12, artikel-id e0168700Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Parkinsons disease and other alpha-synucleinopathies are progressive neurodegenerative diseases characterized by aggregates of misfolded alpha-synuclein spreading throughout the brain. Recent evidence suggests that the pathological progression is likely due to neuron-to-neuron transfer of these aggregates between neuroanatomically connected areas of the brain. As the impact of this pathological spreading mechanism is currently debated, we aimed to investigate the transfer and subcellular location of alpha-synuclein species in a novel 3D co-culture human cell model based on highly differentiated SH-SY5Y cells. Fluorescently-labeled monomeric, oligomeric and fibrillar species of alpha-synuclein were introduced into a donor cell population and co-cultured with an EGFP-expressing acceptor-cell population of differentiated neuron-like cells. Subsequent transfer and colocalization of the different species were determined with confocal microscopy. We could confirm cell-to-cell transfer of all three alpha-synuclein species investigated. Interestingly the level of transferred oligomers and fibrils and oligomers were significantly higher than monomers, which could affect the probability of seeding and pathology in the recipient cells. Most alpha-synuclein colocalized with the lysosomal/endosomal system, both pre- and postsynaptically, suggesting its importance in the processing and spreading of alpha-synuclein.

  • 2.
    Reyes, Juan
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Sackmann, Christopher
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Hoffmann, Alana
    Univ Hosp Erlangen, Germany.
    Svenningsson, Per
    Karolinska Inst, Sweden.
    Winkler, Juergen
    Univ Hosp Erlangen, Germany.
    Ingelsson, Martin
    Uppsala Univ, Sweden.
    Hallbeck, Martin
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Diagnostikcentrum, Klinisk patologi.
    Binding of -synuclein oligomers to Cx32 facilitates protein uptake and transfer in neurons and oligodendrocytes2019Ingår i: Acta Neuropathologica, ISSN 0001-6322, E-ISSN 1432-0533, Vol. 138, nr 1, s. 23-47Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The intercellular transfer of alpha-synuclein (-syn) has been implicated in the progression of Parkinsons disease (PD) and multiple system atrophy (MSA). The cellular mechanisms underlying this process are now beginning to be elucidated. In this study, we demonstrate that the gap junction protein connexin-32 (Cx32) is centrally involved in the preferential uptake of -syn oligomeric assemblies (o-syn) in neurons and oligodendrocytes. In vitro, we demonstrate a clear correlation between Cx32 expression and o-syn uptake. Pharmacological and genetic strategies targeting Cx32 successfully blocked o-syn uptake. In cellular and transgenic mice modeling PD and MSA, we observed significant upregulation of Cx32 which correlates with -syn accumulation. Notably, we could alsodemonstrate a direct interaction between -syn and Cx32 in two out of four human PD cases that was absent in all four age-matched controls. These data are suggestive of a link between Cx32 and PD pathophysiology. Collectively, our results provide compelling evidence for Cx32 as a novel target for therapeutic intervention in PD and related -synucleinopathies.

  • 3.
    Sackmann, Christopher
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Investigation of the intercellular transmission of α-synuclein, amyloid-β and TDP-432019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), frontotemporal lobar dementia (FTLD) and amyotrophic lateral sclerosis (ALS) are disorders characterized by the progressive deposition of proteinaceous inclusions throughout the brain in a predictable manner. Each disease is described by the involvement of different misfolded and aggregated proteins (AD, amyloid-β and tau; PD, α-synuclein; ALS and FTLD, TDP-43) that spread between anatomically connected brain regions, causing cell death in previously healthy regions. Disease progresses as these aggregated proteins spread throughout the brain in a prion-like fashion. Oligomeric forms of these proteins (aggregates comprising of ≈3-30 individual proteins) are thought to be the most relevant to disease, as they are capable of prion-like propagation and can cause cellular toxicity. The work in this thesis aims to elucidate the mechanisms by which different neurodegenerative disease related proteins (amyloid-β, α-synuclein and TDP-43) are taken up and transferred between cells, and the effects exerted by these proteins on downstream cells.

    Paper I examined the uptake and cell to cell transmission of oligomeric α-synuclein (α-syn). Using a 3D co-culture model, we determined that α-syn (monomeric, oligomeric and fibrillar assemblies) were readily taken up and transferred between neuron-like cells, and that this transfer was mediated by an endosomal/lysosomal mechanism. It was also determined that larger α-syn assemblies (oligomers and fibrils) were found in donor and acceptor cells more frequently than monomeric α-syn, which we speculate is a due to the larger aggregates’ resistance to cellular proteases.

    In Paper II, we identified a novel mechanism for the uptake of oligomeric proteins, in the discovery that the gap junction channel protein connexin 32 mediates the uptake of α-syn oligomers in a preferential manner. Gap junction proteins act as a means of communication between adjacent cells, forming a transmembrane pore to facilitate the passage of small molecules. Here, we determined that connexin 32 drives the preferential uptake of oligomeric α-syn relative to monomeric and fibrillar α-syn. This system was not exclusive to α-syn however, as the preferential uptake of oligomeric amyloid-β (Aβ) was also observed. In addition to the uptake of oligomers, we observed that increased α-syn expression elicited the increased expression of connexin 32, in a positive feedback mechanism. When connexin 32 was inhibited pharmacologically or knocked out using CRISPR/Cas9, the preferential uptake of oligomers was abolished. These phenomena were also observed in oligodendrocytes (the accumulation of oligomeric α-syn in oligodendrocytes is a hallmark of Multiple Systems Atrophy), three different mouse models of α-syn overexpression, as well as in post-mortem human tissues.

    Paper III undertook the investigation of cell to cell transfer of TDP-43. Although it was recently confirmed that TDP-43 propagates throughout the brain in a prion-like fashion, it remains unclear how post-translational modifications of TDP-43 affect its propensity to be transferred between cells. This leaves a gap in the understanding of how TDP-43 proteinopathies progress, as post-translationally modified TDP-43 is understood to be critical to pathogenesis. To study this, we generated several TDP-43 cell lines, expressing full-length TDP-43 or C-/N-terminally truncated fragments, known contributors to TDP-43 proteinopathies. Using the 3D co-culture model, we determined that preservation of the N-terminus of TDP-43 enhanced its ability to transmit between cells, whereas an intact the C-terminus reduced transfer. Additionally, since we have previously shown that both oligomeric Aβ and α-syn are incorporated into extracellular vesicles (EVs) such as exosomes, and that these EVs can sufficiently mediate the transfer of protein oligomers to downstream cells, we investigated whether this was also true for TDP-43. We demonstrated that full-length TDP-43 and TDP-43 fragments could be found within EVs generated by these cells, but that these EVs were unable to propagate the protein to downstream cells. Instead, the transmission of TDP-43 occurs in a manner dependent upon physical proximity between cells, possibly across the synaptic cleft itself.

    Next, we studied the acute effects exerted by oligomeric Aβ upon healthy neurons in order to understand the earliest effects of oligomeric Aβ challenge. In Paper IV, we used iPSC-derived neurons generated from human donors expressing different amyloid-β precursor protein (APP) genes, one harbouring the familial AD-causing V717I London mutation, the other expressing WT APP. After differentiating these cells into functional neurons in vitro, the neurons were challenged with acute exposure to exogenous oligomeric Aβ and analyzed by LC-MS/MS to observe the early effects. By analyzing the proteome and phosphoproteome of these cells, we identified many proteins and phosphoproteins that were up- or down-regulated in response to oligomeric Aβ at this early timepoint. Among these changes, oligomeric Aβ caused the downregulation of TDP-43, heterogeneous nuclear ribonucleoproteins, and coatomer complex I proteins. Conversely, increases were observed in 20S proteasome subunits and vesicle associated proteins VAMP1/2. We also observed the differential phosphorylation of tau at serine 208, indicating that phosphorylation at this residue might be an important early event in tauopathy.

    Altogether, the work described in this thesis has provided new understanding as to how different neurodegenerative disease related proteins are taken up and transferred between cells. In doing so, we have identified some of the mechanisms by which this spreading occurs, and that the changes elicited by these toxic oligomeric proteins are rapid and widespread. By learning about these processes, we have identified novel targets that could be used in the development of disease modifying therapeutics.

    Delarbeten
    1. Aggregated Alpha-Synuclein Transfer Efficiently between Cultured Human Neuron-Like Cells and Localize to Lysosomes
    Öppna denna publikation i ny flik eller fönster >>Aggregated Alpha-Synuclein Transfer Efficiently between Cultured Human Neuron-Like Cells and Localize to Lysosomes
    Visa övriga...
    2016 (Engelska)Ingår i: PLOS ONE, ISSN 1932-6203, Vol. 11, nr 12, artikel-id e0168700Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Parkinsons disease and other alpha-synucleinopathies are progressive neurodegenerative diseases characterized by aggregates of misfolded alpha-synuclein spreading throughout the brain. Recent evidence suggests that the pathological progression is likely due to neuron-to-neuron transfer of these aggregates between neuroanatomically connected areas of the brain. As the impact of this pathological spreading mechanism is currently debated, we aimed to investigate the transfer and subcellular location of alpha-synuclein species in a novel 3D co-culture human cell model based on highly differentiated SH-SY5Y cells. Fluorescently-labeled monomeric, oligomeric and fibrillar species of alpha-synuclein were introduced into a donor cell population and co-cultured with an EGFP-expressing acceptor-cell population of differentiated neuron-like cells. Subsequent transfer and colocalization of the different species were determined with confocal microscopy. We could confirm cell-to-cell transfer of all three alpha-synuclein species investigated. Interestingly the level of transferred oligomers and fibrils and oligomers were significantly higher than monomers, which could affect the probability of seeding and pathology in the recipient cells. Most alpha-synuclein colocalized with the lysosomal/endosomal system, both pre- and postsynaptically, suggesting its importance in the processing and spreading of alpha-synuclein.

    Ort, förlag, år, upplaga, sidor
    PUBLIC LIBRARY SCIENCE, 2016
    Nationell ämneskategori
    Neurovetenskaper
    Identifikatorer
    urn:nbn:se:liu:diva-134306 (URN)10.1371/journal.pone.0168700 (DOI)000391222000063 ()28030591 (PubMedID)
    Anmärkning

    Funding Agencies|Swedish Research Council [MH: 523-2013-2735]; Swedish Brain Power Program; Research Foundation of the Swedish Parkinsons Disease Association; Ostergotland Research Foundation for Parkinsons Disease; Parkinson Research Foundation; Hans-Gabriel and Alice Trolle-Wachtmeister Foundation for Medical Research; Gustav V and Queen Victorias Foundation; Swedish Dementia Foundation; Linkoping University Neurobiology Centre; County Council of Ostergotland; Marianne and Marcus Wallenberg Foundation

    Tillgänglig från: 2017-02-06 Skapad: 2017-02-03 Senast uppdaterad: 2019-10-14
    2. Binding of -synuclein oligomers to Cx32 facilitates protein uptake and transfer in neurons and oligodendrocytes
    Öppna denna publikation i ny flik eller fönster >>Binding of -synuclein oligomers to Cx32 facilitates protein uptake and transfer in neurons and oligodendrocytes
    Visa övriga...
    2019 (Engelska)Ingår i: Acta Neuropathologica, ISSN 0001-6322, E-ISSN 1432-0533, Vol. 138, nr 1, s. 23-47Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The intercellular transfer of alpha-synuclein (-syn) has been implicated in the progression of Parkinsons disease (PD) and multiple system atrophy (MSA). The cellular mechanisms underlying this process are now beginning to be elucidated. In this study, we demonstrate that the gap junction protein connexin-32 (Cx32) is centrally involved in the preferential uptake of -syn oligomeric assemblies (o-syn) in neurons and oligodendrocytes. In vitro, we demonstrate a clear correlation between Cx32 expression and o-syn uptake. Pharmacological and genetic strategies targeting Cx32 successfully blocked o-syn uptake. In cellular and transgenic mice modeling PD and MSA, we observed significant upregulation of Cx32 which correlates with -syn accumulation. Notably, we could alsodemonstrate a direct interaction between -syn and Cx32 in two out of four human PD cases that was absent in all four age-matched controls. These data are suggestive of a link between Cx32 and PD pathophysiology. Collectively, our results provide compelling evidence for Cx32 as a novel target for therapeutic intervention in PD and related -synucleinopathies.

    Ort, förlag, år, upplaga, sidor
    SPRINGER, 2019
    Nyckelord
    Parkinsons disease (PD); Multiple system atrophy (MSA); Alzheimers disease (AD); Cell-to-cell transfer; Prion-like transfer; Gap junction proteins; Cx32; GJB1; alpha-Synuclein (-syn)
    Nationell ämneskategori
    Neurovetenskaper
    Identifikatorer
    urn:nbn:se:liu:diva-158850 (URN)10.1007/s00401-019-02007-x (DOI)000471708700002 ()30976973 (PubMedID)
    Anmärkning

    Funding Agencies|Swedish Research Council [523-2013-2735]; Deutsche Forschungsgemeinschaft (DFG) [GRK2162]

    Tillgänglig från: 2019-07-16 Skapad: 2019-07-16 Senast uppdaterad: 2019-10-14
  • 4.
    Sackmann, Valerie
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Diagnostikcentrum, Klinisk patologi.
    Ansell - Schultz, Anna
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Diagnostikcentrum, Klinisk patologi.
    Sackmann, Christopher
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Diagnostikcentrum, Klinisk patologi.
    Lund, Harald
    Karolinska Hospital Solna, Sweden.
    Harris, Robert A.
    Karolinska Hospital Solna, Sweden.
    Hallbeck, Martin
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Diagnostikcentrum, Klinisk patologi.
    Nilsberth, Camilla
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Närsjukvården i centrala Östergötland, Medicinska och geriatriska akutkliniken.
    Anti-inflammatory (M2) macrophage media reduce transmission of oligomeric amyloid beta in differentiated SH-SY5Y cells2017Ingår i: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 60, s. 173-182Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Neuroinflammation plays an influential role in Alzheimers disease (AD), although the mechanisms underlying this phenomenon remain largely unknown. Microglia are thought to be responsible for the majority of these effects and can be characterized into resting (M0), proinflammatory (M1), or anti-inflammatory (M2) functional phenotypes. We investigated the effects of conditioned macrophage media, as an analogue to microglia, on the transfer of oligomeric amyloid beta (oA beta) between differentiated SH-SY5Y cells. We also investigated how the different inflammatory environments related to intercellular and intracellular changes. We demonstrate that M2 products decrease interneuronal transfer of oA beta, while recombinant interleukin (IL)-4, IL-10, and IL-13 increase transfer. There were no alterations to the mRNA of a number of AD-related genes in response to the combination of oA beta and M0, M1, or M2, but several intracellular proteins, some relating to protein trafficking and the endosomal/lysosomal system, were altered. Stimulating microglia to an M2 phenotype may thus slow down the progression of AD and could be a target for future therapies. (C) 2017 Elsevier Inc. All rights reserved.

  • 5.
    Sackmann, Valerie
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Sardar Sinha, Maitrayee
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Sackmann, Christopher
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Civitelli, Livia
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Bergstrom, Joakim
    Uppsala Univ, Sweden.
    Ansell - Schultz, Anna
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Hallbeck, Martin
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Diagnostikcentrum, Klinisk patologi.
    Inhibition of nSMase2 Reduces the Transfer of Oligomeric alpha-Synuclein Irrespective of Hypoxia2019Ingår i: Frontiers in Molecular Neuroscience, ISSN 1662-5099, Vol. 12, artikel-id 200Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recently, extracellular vesicles (EVs), such as exosomes, have been proposed to play an influential role in the cell-to-cell spread of neurodegenerative diseases, including the intercellular transmission of alpha-synuclein (alpha-syn). However, the regulation of EV biogenesis and its relation to Parkinsons disease (PD) is only partially understood. The generation of EVs through the ESCRT-independent pathway depends on the hydrolysis of sphingomyelin by neutral sphingomyelinase 2 (nSMase2) to produce ceramide, which causes the membrane of endosomal multivesicular bodies to bud inward. nSMase2 is sensitive to oxidative stress, a common process in PD brains; however, little is known about the role of sphingomyelin metabolism in the pathogenesis of PD. This is the first study to show that inhibiting nSMase2 decreases the transfer of oligomeric aggregates of alpha-syn between neuron-like cells. Furthermore, it reduced the accumulation and aggregation of high-molecular-weight alpha-syn. Hypoxia, as a model of oxidative stress, reduced the levels of nSMase2, but not its enzymatic activity, and significantly altered the lipid composition of cells without affecting EV abundance or the transfer of alpha-syn. These data show that altering sphingolipids can mitigate the spread of alpha-syn, even under hypoxic conditions, potentially suppressing PD progression.

1 - 5 av 5
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