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  • 1.
    Bergkvist, Liza
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Helmfors, Linda
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Brorsson, Ann-Christin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Co-expression of a disease-associated lysozyme variant with human lysozyme in Drosophila causes accumulation of amyloid deposits and neurodegenerationManuscript (preprint) (Other academic)
    Abstract [en]

    Lysozyme amyloidosis is a dominantly inherited form of amyloid disease. Mutant variants of the protein, with increased tendencies to aggregate compared to the wild type (WT), accumulate in large amyloid deposits in multiple organs, eventually leading to organ failure. Humans affected by lysozyme amyloidosis carry one allele for the wild type protein and one allele encoding for a mutant variant of lysozyme. We have used a Drosophila melanogaster model to investigate the effect of co-expressing WT lysozyme and a mutated variant, F57I, in the central nervous system (CNS) of the fly. In this study, using activity and longevity assays, WT-F57I flies showed a lower activity and a shorter lifespan than flies expressing only WT or the F57I variant of lysozyme (median survival 16 days compared to 34 and 23 respectively). This indicates deteriorating neurological functions in WT-F57I flies; exceeding the decrease in neurological function previously observed for flies only expressing the mutated variant, F57I. In addition, accumulation of insoluble species with amyloid structure was detected for the WT-F57I flies but not for the WT or the F57I flies. Our study show that co-expression of WT lysozyme and the amyloidogenic variant F57I results in neurological damage and is required for accumulation of amyloid deposits, which is characteristic for the disease observed in humans. Our data suggest that insoluble amyloid species or intermediate species, formed on the pathway toward amyloid species, may be cytotoxic and thus contribute to the impaired neurological functions observed for the WT-F57I flies.

  • 2. Order onlineBuy this publication >>
    Helmfors, Linda
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Understanding the dual nature of lysozyme: part villain – part hero: A Drosophila melanogaster model of lysozyme amyloidosis2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Amyloid proteins are a distinct class of proteins that can misfold into β-sheet rich structures that later mature to form the characteristic species known as amyloid fibrils, and accumulate in tissues in the human body. The misfolding event is often caused by mutations (or outer factors such as changes in pH) that destabilize the native protein structure. The mature amyloid fibrils were initially believed to be associated with diseases connected to protein misfolding such as Alzheimer’s disease (AD), Parkinson’s disease, transthyretin amyloidosis and lysozyme amyloidosis. However, now it is known that many different factors are involved in these diseases such as failure in protein clearance, lysosomal dysfunction and formation of intermediate misfolded protein species, which possess cytotoxic properties, preceding the formation of mature fibrils.

    In this thesis the amyloidogenic protein lysozyme has been examined in vivo by using Drosophila melanogaster (fruit fly) as a model organism. The effects of over-expressing human lysozyme and amyloidogenic variants in Drosophila have been investigated both in the absence and presence of the serum amyloid P component (SAP), a protein known to interact with amyloid species. In addition, the role of lysozyme in AD has been investigated by  co-expressing human lysozyme and amyloid β in Drosophila.

    The lysozyme protein is an enzyme naturally found in bodily fluids such as tears, breast milk and saliva. It is engaged in the body’s defense and acts by hydrolyzing the cell wall of invading bacteria. Certain disease-associated point mutations in the gene encoding lysozyme destabilize the protein and cause it to misfold which results in systemic amyloidosis. To investigate the in vivo misfolding behavior of lysozyme we developed and established a Drosophila model of lysozyme amyloidosis. SAP is commonly found attached to amyloid deposits in the body; however, the role of SAP in amyloid diseases is unknown. To investigate the effect of SAP in lysozyme misfolding, these two proteins were co-expressed in Drosophila.

    The amyloid β peptide is involved in AD, building up the plaques found in AD patient brains. These plaques trigger neuroinflammation and since lysozyme is upregulated during various inflammation conditions, a possible role of lysozyme in AD was investigated by overexpressing lysozyme in a Drosophila model of AD. Interaction between lysozyme and the amyloid β protein was also studied by biophysical measurements.

    During my work with this thesis, the dual nature of lysozyme emerged; on the one hand a villain, twisted by mutations, causing the lysozyme amyloidosis disease. On the other hand a hero, delaying the toxicity and maybe the neurological damage caused by the amyloid β peptide.

    List of papers
    1. Disease-related amyloidogenic variants of human lysozyme trigger the unfolded protein response and disturb eye development in Drosophila melanogaster
    Open this publication in new window or tab >>Disease-related amyloidogenic variants of human lysozyme trigger the unfolded protein response and disturb eye development in Drosophila melanogaster
    Show others...
    2012 (English)In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 26, no 1, p. 192-202Article in journal (Refereed) Published
    Abstract [en]

    We have created a Drosophila model of lysozyme amyloidosis to investigate the in vivo behavior of disease-associated variants. To achieve this objective, wild-type (WT) protein and the amyloidogenic variants F57I and D67H were expressed in Drosophila melanogaster using the UAS-gal4 system and both the ubiquitous and retinal expression drivers Act5C-gal4 and gmr-gal4. The nontransgenic w(1118) Drosophila line was used as a control throughout. We utilized ELISA experiments to probe lysozyme protein levels, scanning electron microscopy for eye phenotype classification, and immunohistochemistry to detect the unfolded protein response (UPR) activation. We observed that expressing the destabilized F57I and D67H lysozymes triggers UPR activation, resulting in degradation of these variants, whereas the WT lysozyme is secreted into the fly hemolymph. Indeed, the level of WT was up to 17 times more abundant than the variant proteins. In addition, the F57I variant gave rise to a significant disruption of the eye development, and this correlated to pronounced UPR activation. These results support the concept that the onset of familial amyloid disease is linked to an inability of the UPR to degrade completely the amyloidogenic lysozymes prior to secretion, resulting in secretion of these destabilized variants, thereby leading to deposition and associated organ damage.-Kumita, J. R., Helmfors, L., Williams, J., Luheshi, L. M., Menzer, L., Dumoulin, M., Lomas, D. A., Crowther, D. C., Dobson, C. M., Brorsson, A.-C. Disease-related amyloidogenic variants of human lysozyme trigger the unfolded protein response and disturb eye development in Drosophila melanogaster.

    Place, publisher, year, edition, pages
    Federation of American Society of Experimental Biology (FASEB), 2012
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-73186 (URN)10.1096/fj.11-185983 (DOI)000299202200020 ()21965601 (PubMedID)
    Note

    funding agencies|Swedish Research Council||Biotechnology and Biological Sciences Research Council| BB/E019927/1 BBH0038431 |Wellcome Trust||Leverhulme Trust||European Commission| LSHM-CT-2006-037525/EURAMY |Medical Research Council| G0700990 |VINNOVA||

    Available from: 2011-12-21 Created: 2011-12-21 Last updated: 2017-12-08
    2. SAP to the rescue: Serum amyloid p component ameliorates neurological damage caused by expressing a lysozyme variant in the central nervous system of Drosophila melanogaster
    Open this publication in new window or tab >>SAP to the rescue: Serum amyloid p component ameliorates neurological damage caused by expressing a lysozyme variant in the central nervous system of Drosophila melanogaster
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Lysozyme amyloidosis is a hereditary disease in which mutations in the gene encoding lysozyme leads to misfolding and consequently accumulation of amyloid material. To improve understanding of the processes involved we expressed human wild type (WT) lysozyme and the disease-associated variant F57I in the central nervous system (CNS) of a Drosophila melanogaster model of lysozyme amyloidosis, with and without serum amyloid p component (SAP). We found that flies expressing the amyloidogenic variant F57I in the CNS have a shorter lifespan and lower locomotor activity than flies expressing WT lysozyme or control flies, indicating that the flies’ neurological functions are impaired when F57I is expressed in the nerve cells. In addition, the Unfolded Protein Response (UPR) was upregulated in the F57I-expressing flies. However, co-expression of SAP in the CNS restored the F57I flies’ locomotor activity and lifespan. Thus, SAP has apparent ability to protect nerve cells from damage caused by F57I. Furthermore, co-expression of SAP prevented accumulation of insoluble forms of lysozyme in both WT- and F57I-expressing flies and delayed up-regulation of the UPR by 10 days in F57I flies. Our findings suggest that SAP can prevent cytotoxic effects of expressing F57I in fly CNS by retaining F57I in a soluble form and preventing crowding of misfolded F57I species in the endoplasmic reticulum.

    Keywords
    xbp1-EGFP, ER stress, iFly, Amyloidosis, Misfolding
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-106644 (URN)
    Available from: 2014-05-16 Created: 2014-05-16 Last updated: 2014-05-16
    3. Co-expression of a disease-associated lysozyme variant with human lysozyme in Drosophila causes accumulation of amyloid deposits and neurodegeneration
    Open this publication in new window or tab >>Co-expression of a disease-associated lysozyme variant with human lysozyme in Drosophila causes accumulation of amyloid deposits and neurodegeneration
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Lysozyme amyloidosis is a dominantly inherited form of amyloid disease. Mutant variants of the protein, with increased tendencies to aggregate compared to the wild type (WT), accumulate in large amyloid deposits in multiple organs, eventually leading to organ failure. Humans affected by lysozyme amyloidosis carry one allele for the wild type protein and one allele encoding for a mutant variant of lysozyme. We have used a Drosophila melanogaster model to investigate the effect of co-expressing WT lysozyme and a mutated variant, F57I, in the central nervous system (CNS) of the fly. In this study, using activity and longevity assays, WT-F57I flies showed a lower activity and a shorter lifespan than flies expressing only WT or the F57I variant of lysozyme (median survival 16 days compared to 34 and 23 respectively). This indicates deteriorating neurological functions in WT-F57I flies; exceeding the decrease in neurological function previously observed for flies only expressing the mutated variant, F57I. In addition, accumulation of insoluble species with amyloid structure was detected for the WT-F57I flies but not for the WT or the F57I flies. Our study show that co-expression of WT lysozyme and the amyloidogenic variant F57I results in neurological damage and is required for accumulation of amyloid deposits, which is characteristic for the disease observed in humans. Our data suggest that insoluble amyloid species or intermediate species, formed on the pathway toward amyloid species, may be cytotoxic and thus contribute to the impaired neurological functions observed for the WT-F57I flies.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-106645 (URN)
    Available from: 2014-05-16 Created: 2014-05-16 Last updated: 2014-05-16Bibliographically approved
    4. A protective role of lysozyme in Alzheimer disease
    Open this publication in new window or tab >>A protective role of lysozyme in Alzheimer disease
    Show others...
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Alzheimer disease (AD) is a devastating neurodegenerative disorder where extracellular plaques composed of amyloid β (Aβ) peptides and neuroinflammation are some of the main hallmarks of the disease. Activated microglial cells, which are the resident macrophages in the central nervous system, are suggested to trigger the inflammation response in AD. To discover neuroinflammation biomarkers would be important to reveal the pathological mechanisms of AD and develop therapies that target inflammation mediators. Lysozyme is part of the innate immune system and is secreted from macrophages during various inflammation conditions. However, the involvement of lysozyme in AD pathology has not been explored previously. We have discovered that lysozyme is up-regulated in cerebrospinal fluid from AD patients. Cells exposed to Aβ increased the expression of lysozyme indicating that Aβ might be responsible for the upregulation of lysozyme detected in cerebrospinal fluid. In vitro studies revealed that lysozyme binds to monomeric Aβ1-42 and alters the aggregation pathway counteracting formation of toxic Aβ species. In a newly developed Drosophila model, co-expression of lysozyme with Aβ in brain neurons reduced the formation of insoluble Aβ species, prolonged the survival and improved the activity of the double transgenic flies compared to flies only expressing Aβ. Our findings identify lysozyme as a modulator of Aβ aggregation and toxicity and our discoveries has the potential to be used for development of new treatment strategies and to use lysozyme as a biomarker for AD.

    Keywords
    Lysozyme, Biomarker, Alzheimer disease, Drosophila, CSF, Aβ aggregation
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-106646 (URN)
    Available from: 2014-05-16 Created: 2014-05-16 Last updated: 2021-12-28Bibliographically approved
    Download full text (pdf)
    Understanding the dual nature of lysozyme: part villain – part hero: A Drosophila melanogaster model of lysozyme amyloidosis
    Download (pdf)
    omslag
  • 3.
    Helmfors, Linda
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Armstrong, Andrea
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Civitelli, Livia
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Sandin, Linnea
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Nath, Sangeeta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Janefjord, Camilla
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Zetterberg, Henrik
    Clinical Neurochemistry Laboratory, Department of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden.
    Blennow, Kaj
    Clinical Neurochemistry Laboratory, Department of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden.
    Garner, Brett
    Illawarra Health and Medical Research Institute University of Wollongong, Australia.
    Brorsson, Ann-Christin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Kågedal, Katarina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    A protective role of lysozyme in Alzheimer diseaseManuscript (preprint) (Other academic)
    Abstract [en]

    Alzheimer disease (AD) is a devastating neurodegenerative disorder where extracellular plaques composed of amyloid β (Aβ) peptides and neuroinflammation are some of the main hallmarks of the disease. Activated microglial cells, which are the resident macrophages in the central nervous system, are suggested to trigger the inflammation response in AD. To discover neuroinflammation biomarkers would be important to reveal the pathological mechanisms of AD and develop therapies that target inflammation mediators. Lysozyme is part of the innate immune system and is secreted from macrophages during various inflammation conditions. However, the involvement of lysozyme in AD pathology has not been explored previously. We have discovered that lysozyme is up-regulated in cerebrospinal fluid from AD patients. Cells exposed to Aβ increased the expression of lysozyme indicating that Aβ might be responsible for the upregulation of lysozyme detected in cerebrospinal fluid. In vitro studies revealed that lysozyme binds to monomeric Aβ1-42 and alters the aggregation pathway counteracting formation of toxic Aβ species. In a newly developed Drosophila model, co-expression of lysozyme with Aβ in brain neurons reduced the formation of insoluble Aβ species, prolonged the survival and improved the activity of the double transgenic flies compared to flies only expressing Aβ. Our findings identify lysozyme as a modulator of Aβ aggregation and toxicity and our discoveries has the potential to be used for development of new treatment strategies and to use lysozyme as a biomarker for AD.

  • 4.
    Helmfors, Linda
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Bergkvist, Liza
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Brorsson, Ann-Christin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    SAP to the rescue: Serum amyloid p component ameliorates neurological damage caused by expressing a lysozyme variant in the central nervous system of Drosophila melanogasterManuscript (preprint) (Other academic)
    Abstract [en]

    Lysozyme amyloidosis is a hereditary disease in which mutations in the gene encoding lysozyme leads to misfolding and consequently accumulation of amyloid material. To improve understanding of the processes involved we expressed human wild type (WT) lysozyme and the disease-associated variant F57I in the central nervous system (CNS) of a Drosophila melanogaster model of lysozyme amyloidosis, with and without serum amyloid p component (SAP). We found that flies expressing the amyloidogenic variant F57I in the CNS have a shorter lifespan and lower locomotor activity than flies expressing WT lysozyme or control flies, indicating that the flies’ neurological functions are impaired when F57I is expressed in the nerve cells. In addition, the Unfolded Protein Response (UPR) was upregulated in the F57I-expressing flies. However, co-expression of SAP in the CNS restored the F57I flies’ locomotor activity and lifespan. Thus, SAP has apparent ability to protect nerve cells from damage caused by F57I. Furthermore, co-expression of SAP prevented accumulation of insoluble forms of lysozyme in both WT- and F57I-expressing flies and delayed up-regulation of the UPR by 10 days in F57I flies. Our findings suggest that SAP can prevent cytotoxic effects of expressing F57I in fly CNS by retaining F57I in a soluble form and preventing crowding of misfolded F57I species in the endoplasmic reticulum.

  • 5.
    Helmfors, Linda
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Bergkvist, Liza
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Brorsson, Ann-Christin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Serum Amyloid P Component Ameliorates Neurological Damage Caused by Expressing a Lysozyme Variant in the Central Nervous System of Drosophila melanogaster2016In: PLOS ONE, E-ISSN 1932-6203, Vol. 11, no 7, p. e0159294-Article in journal (Refereed)
    Abstract [en]

    Lysozyme amyloidosis is a hereditary disease in which mutations in the gene coding for lysozyme leads to misfolding and consequently accumulation of amyloid material. To improve understanding of the processes involved we expressed human wild type (WT) lysozyme and the disease-associated variant F57I in the central nervous system (CNS) of a Drosophila melanogaster model of lysozyme amyloidosis, with and without co-expression of serum amyloid p component (SAP). SAP is known to be a universal constituent of amyloid deposits and to associate with lysozyme fibrils. There are clear indications that SAP may play an important role in lysozyme amyloidosis, which requires further elucidation. We found that flies expressing the amyloidogenic variant F57I in the CNS have a shorter lifespan than flies expressing WT lysozyme. We also identified apoptotic cells in the brains of F57I flies demonstrating that the flies neurological functions are impaired when F57I is expressed in the nerve cells. However, co-expression of SAP in the CNS prevented cell death and restored the F57I flies lifespan. Thus, SAP has the apparent ability to protect nerve cells from damage caused by F57I. Furthermore, it was found that co-expression of SAP prevented accumulation of insoluble forms of lysozyme in both WT- and F57I-expressing flies. Our findings suggest that the F57I mutation affects the aggregation process of lysozyme resulting in the formation of cytotoxic species and that SAP is able to prevent cell death in the F57I flies by preventing accumulation of toxic F57I structures.

    Download full text (pdf)
    fulltext
  • 6.
    Helmfors, Linda
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, Faculty of Science & Engineering.
    Boman, Andrea
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Civitelli, Livia
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Nath, Sangeeta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Sandin, Linnea
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Janefjord, Camilla
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    McCann, Heather
    Neuroscience Research Australia and University of New South Wales, Australia.
    Zetterberg, Henrik
    Clinical Neurochemistry Laboratory, Department of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden / UCL Institute of Neurology, Queen Square, London, United Kingdom.
    Blennow, Kaj
    Clinical Neurochemistry Laboratory, Department of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden.
    Halliday, Glenda
    UCL Institute of Neurology, Queen Square, London, United Kingdom.
    Brorsson, Ann-Christin
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, Faculty of Science & Engineering.
    Kågedal, Katarina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Protective properties of lysozyme on β-amyloid pathology: implications for Alzheimer disease2015In: Neurobiology of Disease, ISSN 0969-9961, E-ISSN 1095-953X, Vol. 83, p. 122-133Article in journal (Refereed)
    Abstract [en]

    The hallmarks of Alzheimer disease are amyloid-β plaques and neurofibrillary tangles accompanied by signs of neuroinflammation. Lysozyme is a major player in the innate immune system and has recently been shown to prevent the aggregation of amyloid-β1-40 in vitro. In this study we found that patients with Alzheimer disease have increased lysozyme levels in the cerebrospinal fluid and lysozyme co-localized with amyloid-β in plaques. In Drosophila neuronal co-expression of lysozyme and amyloid-β1-42 reduced the formation of soluble and insoluble amyloid-β species, prolonged survival and improved the activity of amyloid-β1-42 transgenic flies. This suggests that lysozyme levels rise in Alzheimer disease as a compensatory response to amyloid-β increases and aggregation. In support of this, in vitro aggregation assays revealed that lysozyme associates with amyloid-β1-42 and alters its aggregation pathway to counteract the formation of toxic amyloid-β species. Overall, these studies establish a protective role for lysozyme against amyloid-β associated toxicities and identify increased lysozyme in patients with Alzheimer disease. Therefore, lysozyme has potential as a new biomarker as well as a therapeutic target for Alzheimer disease.

    Download full text (pdf)
    fulltext
  • 7.
    Kumita, Janet R
    et al.
    University of Cambridge.
    Helmfors, Linda
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, The Institute of Technology.
    Williams, Jocy
    University of Cambridge.
    Luheshi, Leila M
    University of Cambridge.
    Menzer, Linda
    University of Liège.
    Dumoulin, Mireille
    University of Liège.
    Lomas, David A
    Cambridge Institute for Medical Research.
    Crowther, Damian C
    Cambridge Institute for Medical Research.
    Dobson, Christopher M
    University of Cambridge.
    Brorsson, Ann-Christin
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, The Institute of Technology.
    Disease-related amyloidogenic variants of human lysozyme trigger the unfolded protein response and disturb eye development in Drosophila melanogaster2012In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 26, no 1, p. 192-202Article in journal (Refereed)
    Abstract [en]

    We have created a Drosophila model of lysozyme amyloidosis to investigate the in vivo behavior of disease-associated variants. To achieve this objective, wild-type (WT) protein and the amyloidogenic variants F57I and D67H were expressed in Drosophila melanogaster using the UAS-gal4 system and both the ubiquitous and retinal expression drivers Act5C-gal4 and gmr-gal4. The nontransgenic w(1118) Drosophila line was used as a control throughout. We utilized ELISA experiments to probe lysozyme protein levels, scanning electron microscopy for eye phenotype classification, and immunohistochemistry to detect the unfolded protein response (UPR) activation. We observed that expressing the destabilized F57I and D67H lysozymes triggers UPR activation, resulting in degradation of these variants, whereas the WT lysozyme is secreted into the fly hemolymph. Indeed, the level of WT was up to 17 times more abundant than the variant proteins. In addition, the F57I variant gave rise to a significant disruption of the eye development, and this correlated to pronounced UPR activation. These results support the concept that the onset of familial amyloid disease is linked to an inability of the UPR to degrade completely the amyloidogenic lysozymes prior to secretion, resulting in secretion of these destabilized variants, thereby leading to deposition and associated organ damage.-Kumita, J. R., Helmfors, L., Williams, J., Luheshi, L. M., Menzer, L., Dumoulin, M., Lomas, D. A., Crowther, D. C., Dobson, C. M., Brorsson, A.-C. Disease-related amyloidogenic variants of human lysozyme trigger the unfolded protein response and disturb eye development in Drosophila melanogaster.

    Download full text (pdf)
    fulltext
  • 8.
    Pathak, Surajit
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Meng, Wen-Jian
    Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology. Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Sichuan University, Peoples R China.
    Kumar Nandy, Suman
    University of Kalyani, India.
    Ping, Jie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology.
    Bisgin, Atil
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Helmfors, Linda
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Waldmann, Patrik
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    Sun, Xiao-Feng
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology.
    Radiation and SN38 treatments modulate the expression of microRNAs, cytokines and chemokines in colon cancer cells in a p53-directed manner2015In: Oncotarget, E-ISSN 1949-2553, Vol. 6, no 42, p. 44758-44780Article in journal (Refereed)
    Abstract [en]

    Aberrant expression of miRNAs, cytokines and chemokines are involved in pathogenesis of colon cancer. However, the expression of p53 mediated miRNAs, cyto- and chemokines after radiation and SN38 treatment in colon cancer remains elusive. Here, human colon cancer cells, HCT116 with wild-type, heterozygous and a functionally null p53, were treated by radiation and SN38. The expression of 384 miRNAs was determined by using the TaqMan (R) miRNA array, and the expression of cyto- and chemokines was analyzed by Meso-Scale-Discovery instrument. Up- or down-regulations of miRNAs after radiation and SN38 treatments were largely dependent on p53 status of the cells. Cytokines, IL-6, TNF-alpha, IL-1 beta, Il-4, IL-10, VEGF, and chemokines, IL-8, MIP-1 alpha were increased, and IFN-gamma expression was decreased after radiation, whereas, IL-6, IFN-gamma, TNF-alpha, IL-1 beta, Il-4, IL-10, IL-8 were decreased, and VEGF and MIP-1 alpha were increased after SN38 treatment. Bioinformatic analysis pointed out that the highly up-regulated miRNAs, let-7f-5p, miR-455-3p, miR-98, miR-155-5p and the down-regulated miRNAs, miR-1, miR-127-5p, miR-142-5p, miR-202-5p were associated with colon cancer pathways and correlated with cyto- or chemokine expression. These miRNAs have the potential for use in colon cancer therapy as they are related to p53, pro- or anti-inflammatory cyto- or chemokines after the radiation and SN38 treatment.

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    fulltext
  • 9.
    Sandin, Linnea
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Bergkvist, Liza
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Physics, Chemistry and Biology, Chemistry.
    Nath, Sangeeta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Kielkopf, Claudia
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Janefjord, Camilla
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Helmfors, Linda
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Zetterberg, Henrik
    Clinical Neurochemistry Laboratory, Department of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden / UCL Institute of Neurology, London, UK.
    Blennow, Kaj
    Clinical Neurochemistry Laboratory, Department of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden.
    Li, Hongyun
    Illawarra Health and Medical Research Institute, University of Wollongong, Australia.
    Nilsberth, Camilla
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Acute Internal Medicine and Geriatrics.
    Garner, Brett
    Illawarra Health and Medical Research Institute, University of Wollongong, Australia / School of Biological Sciences, University of Wollongong, Australia.
    Brorsson, Ann-Christin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Kågedal, Katarina
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Beneficial effects of increased lysozyme levels in Alzheimer’s disease modelled in Drosophila melanogaster2016In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 283, no 19, p. 3508-3522Article in journal (Refereed)
    Abstract [en]

    Genetic polymorphisms of immune genes that associate with higher risk to develop Alzheimer’s disease (AD) have led to an increased research interest on the involvement of the immune system in AD pathogenesis. A link between amyloid pathology and immune gene expression was suggested in a genome-wide gene expression study of transgenic amyloid mouse models. In this study, the gene expression of lysozyme, a major player in the innate immune system, was found to be increased in a comparable pattern as the amyloid pathology developed in transgenic mouse models of AD. A similar pattern was seen at protein levels of lysozyme in human AD brain and CSF, but this lysozyme pattern was not seen in a tau transgenic mouse model. Lysozyme was demonstrated to be beneficial for different Drosophila melanogaster models of AD. In flies that expressed Aβ1-42 or AβPP together with BACE1 in the eyes, the rough eye phenotype indicative of toxicity was completely rescued by coexpression of lysozyme. In Drosophila flies bearing the Aβ1-42 variant with the Arctic gene mutation, lysozyme increased the fly survival and decreased locomotor dysfunction dose dependently. An interaction between lysozyme and Aβ1-42 in the Drosophila eye was discovered. We propose that the increased levels of lysozyme, seen in mouse models of AD and in human AD cases, were triggered by Aβ1-42 and caused a beneficial effect by binding of lysozyme to toxic species of Aβ1-42, which prevented these from exerting their toxic effects. These results emphasize the possibility of lysozyme as biomarker and therapeutic target for AD.

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