1
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Aalto AL, Luukkonen V, Meinander A. Ubiquitin signalling in Drosophila innate immune responses. FEBS J 2023. [PMID: 38069549 DOI: 10.1111/febs.17028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/24/2023] [Accepted: 12/07/2023] [Indexed: 12/19/2023]
Abstract
Cells respond to invading pathogens and danger signals from the environment by adapting gene expression to meet the need for protective effector molecules. While this innate immune response is required for the cell and the organism to recover, excess immune activation may lead to loss of homeostasis, thereby promoting chronic inflammation and cancer progression. The molecular basis of innate immune defence is comprised of factors promoting survival and proliferation, such as cytokines, antimicrobial peptides and anti-apoptotic proteins. As the molecular mechanisms regulating innate immune responses are conserved through evolution, the fruit fly Drosophila melanogaster serves as a convenient, affordable and ethical model organism to enhance understanding of immune signalling. Fly immunity against bacterial infection is built up by both cellular and humoral responses, where the latter is regulated by the Imd and Toll pathways activating NF-κB transcription factors Relish, Dorsal and Dif, as well as JNK activation and JAK/STAT signalling. As in mammals, the Drosophila innate immune signalling pathways are characterised by ubiquitination of signalling molecules followed by ubiquitin receptors binding to the ubiquitin chains, as well as by rapid changes in protein levels by ubiquitin-mediated targeted proteasomal and lysosomal degradation. In this review, we summarise the molecular signalling pathways regulating immune responses to pathogen infection in Drosophila, with a focus on ubiquitin-dependent control of innate immunity and inflammatory signalling.
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Affiliation(s)
- Anna L Aalto
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland
- InFLAMES Research Flagship, Åbo Akademi University, Turku, Finland
| | - Veera Luukkonen
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland
| | - Annika Meinander
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland
- InFLAMES Research Flagship, Åbo Akademi University, Turku, Finland
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2
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Aalto AL, Saadabadi A, Lindholm F, Kietz C, Himmelroos E, Marimuthu P, Salo-Ahen OMH, Eklund P, Meinander A. Stilbenoid compounds inhibit NF-κB-mediated inflammatory responses in the Drosophila intestine. Front Immunol 2023; 14:1253805. [PMID: 37809071 PMCID: PMC10556681 DOI: 10.3389/fimmu.2023.1253805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/04/2023] [Indexed: 10/10/2023] Open
Abstract
Introduction Stilbenoid compounds have been described to have anti-inflammatory properties in animal models in vivo, and have been shown to inhibit Ca2+-influx through the transient receptor potential ankyrin 1 (TrpA1). Methods To study how stilbenoid compounds affect inflammatory signaling in vivo, we have utilized the fruit fly, Drosophila melanogaster, as a model system. To induce intestinal inflammation in the fly, we have fed flies with the intestinal irritant dextran sodium sulphate (DSS). Results We found that DSS induces severe changes in the bacteriome of the Drosophila intestine, and that this dysbiosis causes activation of the NF-κB transcription factor Relish. We have taken advantage of the DSS-model to study the anti-inflammatory properties of the stilbenoid compounds pinosylvin (PS) and pinosylvin monomethyl ether (PSMME). With the help of in vivo approaches, we have identified PS and PSMME to be transient receptor ankyrin 1 (TrpA1)-dependent antagonists of NF-κB-mediated intestinal immune responses in Drosophila. We have also computationally predicted the putative antagonist binding sites of these compounds at Drosophila TrpA1. Discussion Taken together, we show that the stilbenoids PS and PSMME have anti-inflammatory properties in vivo in the intestine and can be used to alleviate chemically induced intestinal inflammation in Drosophila.
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Affiliation(s)
- Anna L. Aalto
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
- InFLAMES Research Flagship Center, Åbo Akademi University, Turku, Finland
| | - Atefeh Saadabadi
- Pharmaceutical Sciences Laboratory, Pharmacy, Åbo Akademi University, Turku, Finland
- Structural Bioinformatics Laboratory, Biochemistry, Åbo Akademi University, Turku, Finland
- Laboratory of Molecular Science and Engineering, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Fanny Lindholm
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Christa Kietz
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Emmy Himmelroos
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Parthiban Marimuthu
- Pharmaceutical Sciences Laboratory, Pharmacy, Åbo Akademi University, Turku, Finland
- Structural Bioinformatics Laboratory, Biochemistry, Åbo Akademi University, Turku, Finland
| | - Outi M. H. Salo-Ahen
- Pharmaceutical Sciences Laboratory, Pharmacy, Åbo Akademi University, Turku, Finland
- Structural Bioinformatics Laboratory, Biochemistry, Åbo Akademi University, Turku, Finland
| | - Patrik Eklund
- Laboratory of Molecular Science and Engineering, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Annika Meinander
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
- InFLAMES Research Flagship Center, Åbo Akademi University, Turku, Finland
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3
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Virtanen L, Holm E, Halme M, West G, Lindholm F, Gullmets J, Irjala J, Heliö T, Padzik A, Meinander A, Eriksson JE, Taimen P. Lamin A/C phosphorylation at serine 22 is a conserved heat shock response to regulate nuclear adaptation during stress. J Cell Sci 2023; 136:289469. [PMID: 36695453 PMCID: PMC10022683 DOI: 10.1242/jcs.259788] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 01/16/2023] [Indexed: 01/26/2023] Open
Abstract
The heat shock (HS) response is crucial for cell survival in harmful environments. Nuclear lamin A/C, encoded by the LMNA gene, contributes towards altered gene expression during HS, but the underlying mechanisms are poorly understood. Here, we show that upon HS, lamin A/C was reversibly phosphorylated at serine 22 in concert with HSF1 activation in human cells, mouse cells and Drosophila melanogaster in vivo. Consequently, the phosphorylation facilitated nucleoplasmic localization of lamin A/C and nuclear sphericity in response to HS. Interestingly, lamin A/C knock-out cells showed deformed nuclei after HS and were rescued by ectopic expression of wild-type lamin A, but not by a phosphomimetic (S22D) lamin A mutant. Furthermore, HS triggered concurrent downregulation of lamina-associated protein 2α (Lap2α, encoded by TMPO) in wild-type lamin A/C-expressing cells, but a similar response was perturbed in lamin A/C knock-out cells and in LMNA mutant patient fibroblasts, which showed impaired cell cycle arrest under HS and compromised survival at recovery. Taken together, our results suggest that the altered phosphorylation stoichiometry of lamin A/C provides an evolutionarily conserved mechanism to regulate lamina structure and serve nuclear adaptation and cell survival during HS.
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Affiliation(s)
- Laura Virtanen
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, 20520 Turku, Finland
| | - Emilia Holm
- Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland
| | - Mona Halme
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, 20520 Turku, Finland
| | - Gun West
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, 20520 Turku, Finland
| | - Fanny Lindholm
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, 20520 Turku, Finland
| | - Josef Gullmets
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, 20520 Turku, Finland.,Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland
| | - Juho Irjala
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, 20520 Turku, Finland
| | - Tiina Heliö
- Heart and Lung Center, Helsinki University Hospital and University of Helsinki, 00029 Helsinki, Finland
| | - Artur Padzik
- Genome Editing Core, Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Annika Meinander
- Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland
| | - John E Eriksson
- Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland.,Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Pekka Taimen
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, 20520 Turku, Finland.,Department of Pathology, Turku University Hospital, 20520 Turku, Finland
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Abstract
An intact cell death machinery is not only crucial for successful embryonic development and tissue homeostasis, but participates also in the defence against pathogens and contributes to a balanced immune response. Centrally involved in the regulation of both cell death and inflammatory immune responses is the evolutionarily conserved family of cysteine proteases named caspases. The Drosophila melanogaster genome encodes for seven caspases, several of which display dual functions, participating in apoptotic signalling and beyond. Among the Drosophila caspases, the caspase-8 homologue Dredd has a well-characterised role in inflammatory signalling activated by bacterial infections, and functions as a driver of NF-κB-mediated immune responses. Regarding the other Drosophila caspases, studies focusing on tissue-specific immune signalling and host-microbe interactions have recently revealed immunoregulatory functions of the initiator caspase Dronc and the effector caspase Drice. The aim of this review is to give an overview of the signalling cascades involved in the Drosophila humoral innate immune response against pathogens and of their caspase-mediated regulation. Furthermore, the apoptotic role of caspases during antibacterial and antiviral immune activation will be discussed.
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Affiliation(s)
- Christa Kietz
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, BioCity, Turku, Finland
| | - Annika Meinander
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, BioCity, Turku, Finland.
- InFLAMES Research Flagship Center, Åbo Akademi University, Turku, Finland.
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5
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Mung KL, Meinander A, Koskinen PJ. PIM
kinases phosphorylate lactate dehydrogenase A at serine 161 and suppress its nuclear ubiquitination. FEBS J 2022; 290:2489-2502. [PMID: 36239424 DOI: 10.1111/febs.16653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 09/14/2022] [Accepted: 10/13/2022] [Indexed: 11/07/2022]
Abstract
Lactate dehydrogenase A (LDHA) is a glycolytic enzyme catalysing the reversible conversion of pyruvate to lactate. It has been implicated as a substrate for PIM kinases, yet the relevant target sites and functional consequences of phosphorylation have remained unknown. Here, we show that all three PIM family members can phosphorylate LDHA at serine 161. When we investigated the physiological consequences of this phosphorylation in PC3 prostate cancer and MCF7 breast cancer cells, we noticed that it suppressed ubiquitin-mediated degradation of nuclear LDHA and promoted interactions between LDHA and 14-3-3 proteins. By contrast, in CRISPR/Cas9-edited knock-out cells lacking all three PIM family members, ubiquitination of nuclear LDHA was dramatically increased followed by its decreased expression. Our data suggest that PIM kinases support nuclear LDHA expression and activities by promoting phosphorylation-dependent interactions of LDHA with 14-3-3ε, which shields nuclear LDHA from ubiquitin-mediated degradation.
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Affiliation(s)
| | - Annika Meinander
- Faculty of Science and Engineering, Cell Biology, BioCity Åbo Akademi University Turku Finland
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6
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Aalto A, Martínez‐Chacón G, Kietz C, Tsyganova N, Kreutzer J, Kallio P, Broemer M, Meinander A. M1‐linked ubiquitination facilitates NF‐κB activation and survival during sterile inflammation. FEBS J 2022; 289:5180-5197. [PMID: 35263507 PMCID: PMC9543601 DOI: 10.1111/febs.16425] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 12/17/2021] [Accepted: 03/07/2022] [Indexed: 01/03/2023]
Abstract
Methionine 1 (M1)‐linked ubiquitination plays a key role in the regulation of inflammatory nuclear factor‐κB (NF‐κB) signalling and is important for clearance of pathogen infection in Drosophila melanogaster. M1‐linked ubiquitin (M1‐Ub) chains are assembled by the linear ubiquitin E3 ligase (LUBEL) in flies. Here, we have studied the role of LUBEL in sterile inflammation induced by different types of cellular stresses. We have found that the LUBEL catalyses formation of M1‐Ub chains in response to hypoxic, oxidative and mechanical stress conditions. LUBEL is shown to be important for flies to survive low oxygen conditions and paraquat‐induced oxidative stress. This protective action seems to be driven by stress‐induced activation of the NF‐κB transcription factor Relish via the immune deficiency (Imd) pathway. In addition to LUBEL, the intracellular mediators of Relish activation, including the transforming growth factor activating kinase 1 (Tak1), Drosophila inhibitor of apoptosis (IAP) Diap2, the IκB kinase γ (IKKγ) Kenny and the initiator caspase Death‐related ced‐3/Nedd2‐like protein (Dredd), but not the membrane receptor peptidoglycan recognition protein (PGRP)‐LC, are shown to be required for sterile inflammatory response and survival. Finally, we showed that the stress‐induced upregulation of M1‐Ub chains in response to hypoxia, oxidative and mechanical stress is also induced in mammalian cells and protects from stress‐induced cell death. Taken together, our results suggest that M1‐Ub chains are important for NF‐κB signalling in inflammation induced by stress conditions often observed in chronic inflammatory diseases and cancer.
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Affiliation(s)
- Anna Aalto
- Faculty of Science and Engineering, Cell Biology Åbo Akademi University, BioCity Turku Finland
| | | | - Christa Kietz
- Faculty of Science and Engineering, Cell Biology Åbo Akademi University, BioCity Turku Finland
| | - Nadezhda Tsyganova
- Faculty of Science and Engineering, Cell Biology Åbo Akademi University, BioCity Turku Finland
| | - Joose Kreutzer
- Faculty of Medicine and Health Technology BioMediTech Tampere University Finland
| | - Pasi Kallio
- Faculty of Medicine and Health Technology BioMediTech Tampere University Finland
| | - Meike Broemer
- German Center for Neurodegenerative Diseases (DZNE) Bonn Germany
| | - Annika Meinander
- Faculty of Science and Engineering, Cell Biology Åbo Akademi University, BioCity Turku Finland
- InFLAMES Research Flagship Center Åbo Akademi University Turku Finland
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7
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West G, Turunen M, Aalto A, Virtanen L, Li SP, Heliö T, Meinander A, Taimen P. A heterozygous p.S143P mutation in LMNA associates with proteasome dysfunction and enhanced autophagy-mediated degradation of mutant lamins A and C. Front Cell Dev Biol 2022; 10:932983. [PMID: 36111332 PMCID: PMC9468711 DOI: 10.3389/fcell.2022.932983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 07/27/2022] [Indexed: 01/09/2023] Open
Abstract
Lamins A and C are nuclear intermediate filament proteins that form a proteinaceous meshwork called lamina beneath the inner nuclear membrane. Mutations in the LMNA gene encoding lamins A and C cause a heterogenous group of inherited degenerative diseases known as laminopathies. Previous studies have revealed altered cell signaling pathways in lamin-mutant patient cells, but little is known about the fate of mutant lamins A and C within the cells. Here, we analyzed the turnover of lamins A and C in cells derived from a dilated cardiomyopathy patient with a heterozygous p.S143P mutation in LMNA. We found that transcriptional activation and mRNA levels of LMNA are increased in the primary patient fibroblasts, but the protein levels of lamins A and C remain equal in control and patient cells because of a meticulous interplay between autophagy and the ubiquitin-proteasome system (UPS). Both endogenous and ectopic expression of p.S143P lamins A and C cause significantly reduced activity of UPS and an accumulation of K48-ubiquitin chains in the nucleus. Furthermore, K48-ubiquitinated lamins A and C are degraded by compensatory enhanced autophagy, as shown by increased autophagosome formation and binding of lamins A and C to microtubule-associated protein 1A/1B-light chain 3. Finally, chaperone 4-PBA augmented protein degradation by restoring UPS activity as well as autophagy in the patient cells. In summary, our results suggest that the p.S143P-mutant lamins A and C have overloading and deleterious effects on protein degradation machinery and pharmacological interventions with compounds enhancing protein degradation may be beneficial for cell homeostasis.
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Affiliation(s)
- Gun West
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, Turku, Finland,InFLAMES Research Flagship Center, University of Turku and Åbo Akademi University, Turku, Finland
| | - Minttu Turunen
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, Turku, Finland,InFLAMES Research Flagship Center, University of Turku and Åbo Akademi University, Turku, Finland
| | - Anna Aalto
- InFLAMES Research Flagship Center, University of Turku and Åbo Akademi University, Turku, Finland,Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Laura Virtanen
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, Turku, Finland,InFLAMES Research Flagship Center, University of Turku and Åbo Akademi University, Turku, Finland
| | - Song-Ping Li
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, Turku, Finland,InFLAMES Research Flagship Center, University of Turku and Åbo Akademi University, Turku, Finland
| | - Tiina Heliö
- Heart and Lung Center Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Annika Meinander
- InFLAMES Research Flagship Center, University of Turku and Åbo Akademi University, Turku, Finland,Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Pekka Taimen
- Institute of Biomedicine and FICAN West Cancer Centre, University of Turku, Turku, Finland,InFLAMES Research Flagship Center, University of Turku and Åbo Akademi University, Turku, Finland,Department of Pathology, Laboratory Division, Turku University Hospital, Turku, Finland,*Correspondence: Pekka Taimen,
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8
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Kietz C, Mohan AK, Pollari V, Tuominen IE, Ribeiro PS, Meier P, Meinander A. Drice restrains Diap2-mediated inflammatory signalling and intestinal inflammation. Cell Death Differ 2022; 29:28-39. [PMID: 34262145 PMCID: PMC8738736 DOI: 10.1038/s41418-021-00832-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 06/28/2021] [Accepted: 07/06/2021] [Indexed: 02/06/2023] Open
Abstract
The Drosophila IAP protein, Diap2, is a key mediator of NF-κB signalling and innate immune responses. Diap2 is required for both local immune activation, taking place in the epithelial cells of the gut and trachea, and for mounting systemic immune responses in the cells of the fat body. We have found that transgenic expression of Diap2 leads to a spontaneous induction of NF-κB target genes, inducing chronic inflammation in the Drosophila midgut, but not in the fat body. Drice is a Drosophila effector caspase known to interact and form a stable complex with Diap2. We have found that this complex formation induces its subsequent degradation, thereby regulating the amount of Diap2 driving NF-κB signalling in the intestine. Concordantly, loss of Drice activity leads to accumulation of Diap2 and to chronic intestinal inflammation. Interestingly, Drice does not interfere with pathogen-induced signalling, suggesting that it protects from immune responses induced by resident microbes. Accordingly, no inflammation was detected in transgenic Diap2 flies and Drice-mutant flies reared in axenic conditions. Hence, we show that Drice, by restraining Diap2, halts unwanted inflammatory signalling in the intestine.
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Affiliation(s)
- Christa Kietz
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, BioCity, Turku, Finland
| | - Aravind K Mohan
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, BioCity, Turku, Finland
| | - Vilma Pollari
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, BioCity, Turku, Finland
| | - Ida-Emma Tuominen
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, BioCity, Turku, Finland
| | - Paulo S Ribeiro
- Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, London, UK
| | - Pascal Meier
- The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London, UK
| | - Annika Meinander
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, BioCity, Turku, Finland.
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9
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Şen Karaman D, Kietz C, Govardhanam P, Slita A, Manea A, Pamukçu A, Meinander A, Rosenholm JM. Core@shell structured ceria@mesoporous silica nanoantibiotics restrain bacterial growth in vitro and in vivo. Mater Sci Eng C Mater Biol Appl 2021; 133:112607. [PMID: 35525761 DOI: 10.1016/j.msec.2021.112607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 12/02/2021] [Accepted: 12/08/2021] [Indexed: 11/16/2022]
Abstract
Due to its modular and flexible design options, mesoporous silica provides ample opportunities when developing new strategies for combinatory antibacterial treatments. In this study, antibacterial ceria (CeO2) nanoparticles (NP) were used as core material, and were further coated with a mesoporous silica shell (mSiO2) to obtain a core@shell structured nanocomposite (CeO2@mSiO2). The porous silica shell was utilized as drug reservoir, whereby CeO2@mSiO2 was loaded with the antimicrobial agent capsaicin (CeO2@mSiO2/Cap). CeO2@mSiO2/Cap was further surface-coated with the natural antimicrobial polymer chitosan by employing physical adsorption. The obtained nanocomposite, CeO2@mSiO2/Cap@Chit, denoted NAB, which stands for "nanoantibiotic", provided a combinatory antibacterial mode of action. The antibacterial effect of NAB on the Gram-negative bacteria Escherichia coli (E.coli) was proven to be significant in vitro. In addition, in vivo evaluations revealed NAB to inhibit the bacterial growth in the intestine of bacteria-fed Drosophila melanogaster larvae, and decreased the required dose of capsaicin needed to eliminate bacteria. As our constructed CeO2@mSiO2 did not show toxicity to mammalian cells, it holds promise for the development of next-generation nanoantibiotics of non-toxic nature with flexible design options.
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Affiliation(s)
- Didem Şen Karaman
- Department of Biomedical Engineering, Faculty of Engineering and Architecture, İzmir Katip Çelebi University, İzmir, Turkey.
| | - Christa Kietz
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Finland
| | - Prakirth Govardhanam
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, Finland
| | - Anna Slita
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, Finland
| | - Alexandra Manea
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, Finland
| | - Ayşenur Pamukçu
- Department of Biomedical Engineering, Faculty of Engineering and Architecture, İzmir Katip Çelebi University, İzmir, Turkey
| | - Annika Meinander
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Finland.
| | - Jessica M Rosenholm
- Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Åbo Akademi University, Finland
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10
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Qiao X, Liu Y, Prada ML, Mohan AK, Gupta A, Jaiswal A, Sharma M, Merisaari J, Haikala HM, Talvinen K, Yetukuri L, Pylvänäinen JW, Klefström J, Kronqvist P, Meinander A, Aittokallio T, Hietakangas V, Eilers M, Westermarck J. UBR5 Is Coamplified with MYC in Breast Tumors and Encodes an Ubiquitin Ligase That Limits MYC-Dependent Apoptosis. Cancer Res 2020; 80:1414-1427. [PMID: 32029551 DOI: 10.1158/0008-5472.can-19-1647] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 11/21/2019] [Accepted: 01/28/2020] [Indexed: 11/16/2022]
Abstract
For maximal oncogenic activity, cellular MYC protein levels need to be tightly controlled so that they do not induce apoptosis. Here, we show how ubiquitin ligase UBR5 functions as a molecular rheostat to prevent excess accumulation of MYC protein. UBR5 ubiquitinates MYC and its effects on MYC protein stability are independent of FBXW7. Silencing of endogenous UBR5 induced MYC protein expression and regulated MYC target genes. Consistent with the tumor suppressor function of UBR5 (HYD) in Drosophila, HYD suppressed dMYC-dependent overgrowth of wing imaginal discs. In contrast, in cancer cells, UBR5 suppressed MYC-dependent priming to therapy-induced apoptosis. Of direct cancer relevance, MYC and UBR5 genes were coamplified in MYC-driven human cancers. Functionally, UBR5 suppressed MYC-mediated apoptosis in p53-mutant breast cancer cells with UBR5/MYC coamplification. Furthermore, single-cell immunofluorescence analysis demonstrated reciprocal expression of UBR5 and MYC in human basal-type breast cancer tissues. In summary, UBR5 is a novel MYC ubiquitin ligase and an endogenous rheostat for MYC activity. In MYC-amplified, and p53-mutant breast cancer cells, UBR5 has an important role in suppressing MYC-mediated apoptosis priming and in protection from drug-induced apoptosis. SIGNIFICANCE: These findings identify UBR5 as a novel MYC regulator, the inactivation of which could be very important for understanding of MYC dysregulation on cancer cells. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/7/1414/F1.large.jpg.
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Affiliation(s)
- Xi Qiao
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland.,Institute of Biomedicine, University of Turku, Turku, Finland.,TuDMM Doctoral Programme, University of Turku, Turku, Finland
| | - Ying Liu
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Maria Llamazares Prada
- Theodor Boveri Institute and Comprehensive Cancer Center, Mainfranken, Biocenter, University of Würzburg, Würzburg, Germany
| | - Aravind K Mohan
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland
| | - Abhishekh Gupta
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Alok Jaiswal
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Mukund Sharma
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland.,Institute of Biomedicine, University of Turku, Turku, Finland.,TuDMM Doctoral Programme, University of Turku, Turku, Finland
| | - Joni Merisaari
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland.,Institute of Biomedicine, University of Turku, Turku, Finland.,TuDMM Doctoral Programme, University of Turku, Turku, Finland
| | - Heidi M Haikala
- Research Programs Unit/Translational Cancer Medicine & HiLIFE, University of Helsinki, Helsinki, Finland
| | - Kati Talvinen
- Institute of Biomedicine, University of Turku, Turku, Finland
| | - Laxman Yetukuri
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland.,Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Joanna W Pylvänäinen
- Turku BioImaging, University of Turku and Åbo Akademi University, Turku, Finland
| | - Juha Klefström
- Research Programs Unit/Translational Cancer Medicine & HiLIFE, University of Helsinki, Helsinki, Finland
| | | | - Annika Meinander
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland
| | - Tero Aittokallio
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland.,Department of Mathematics and Statistics, University of Turku, Turku, Finland
| | - Ville Hietakangas
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Martin Eilers
- Theodor Boveri Institute and Comprehensive Cancer Center, Mainfranken, Biocenter, University of Würzburg, Würzburg, Germany
| | - Jukka Westermarck
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland. .,Institute of Biomedicine, University of Turku, Turku, Finland
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11
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Aalto AL, Mohan AK, Schwintzer L, Kupka S, Kietz C, Walczak H, Broemer M, Meinander A. M1-linked ubiquitination by LUBEL is required for inflammatory responses to oral infection in Drosophila. Cell Death Differ 2018; 26:860-876. [PMID: 30026495 PMCID: PMC6462001 DOI: 10.1038/s41418-018-0164-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 06/20/2018] [Accepted: 07/02/2018] [Indexed: 01/04/2023] Open
Abstract
Post-translational modifications such as ubiquitination play a key role in regulation of inflammatory nuclear factor-κB (NF-κB) signalling. The Drosophila IκB kinase γ (IKKγ) Kenny is a central regulator of the Drosophila Imd pathway responsible for activation of the NF-κB Relish. We found the Drosophila E3 ligase and HOIL-1L interacting protein (HOIP) orthologue linear ubiquitin E3 ligase (LUBEL) to catalyse formation of M1-linked linear ubiquitin (M1-Ub) chains in flies in a signal-dependent manner upon bacterial infection. Upon activation of the Imd pathway, LUBEL modifies Kenny with M1-Ub chains. Interestingly, the LUBEL-mediated M1-Ub chains seem to be targeted both directly to Kenny and to K63-linked ubiquitin chains conjugated to Kenny by DIAP2. This suggests that DIAP2 and LUBEL work together to promote Kenny-mediated activation of Relish. We found LUBEL-mediated M1-Ub chain formation to be required for flies to survive oral infection with Gram-negative bacteria, for activation of Relish-mediated expression of antimicrobial peptide genes and for pathogen clearance during oral infection. Interestingly, LUBEL is not required for mounting an immune response against systemic infection, as Relish-mediated antimicrobial peptide genes can be expressed in the absence of LUBEL during septic injury. Finally, transgenic induction of LUBEL-mediated M1-Ub drives expression of antimicrobial peptide genes and hyperplasia in the midgut in the absence of infection. This suggests that M1-Ub chains are important for Imd signalling and immune responses in the intestinal epithelia, and that enhanced M1-Ub chain formation is able to drive chronic intestinal inflammation in flies.
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Affiliation(s)
- Anna L Aalto
- Department of Cell Biology, Faculty of Science and Engineering, BioCity, Åbo Akademi University, 20520, Turku, Finland
| | - Aravind K Mohan
- Department of Cell Biology, Faculty of Science and Engineering, BioCity, Åbo Akademi University, 20520, Turku, Finland
| | - Lukas Schwintzer
- German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
| | - Sebastian Kupka
- Centre for Cell Death, Cancer and Inflammation (CCCI), UCL Cancer Institute, London, WC1E 6BT, UK
| | - Christa Kietz
- Department of Cell Biology, Faculty of Science and Engineering, BioCity, Åbo Akademi University, 20520, Turku, Finland
| | - Henning Walczak
- Centre for Cell Death, Cancer and Inflammation (CCCI), UCL Cancer Institute, London, WC1E 6BT, UK
| | - Meike Broemer
- German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
| | - Annika Meinander
- Department of Cell Biology, Faculty of Science and Engineering, BioCity, Åbo Akademi University, 20520, Turku, Finland.
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12
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Kietz C, Pollari V, Meinander A. Generating Germ‐Free
Drosophila
to Study Gut‐Microbe Interactions: Protocol to Rear
Drosophila
Under Axenic Conditions. ACTA ACUST UNITED AC 2018; 77:e52. [DOI: 10.1002/cptx.52] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Christa Kietz
- Faculty of Science and Engineering, Åbo Akademi University Turku Finland
| | - Vilma Pollari
- Faculty of Science and Engineering, Åbo Akademi University Turku Finland
| | - Annika Meinander
- Faculty of Science and Engineering, Åbo Akademi University Turku Finland
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13
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Sahlgren C, Meinander A, Zhang H, Cheng F, Preis M, Xu C, Salminen TA, Toivola D, Abankwa D, Rosling A, Karaman DŞ, Salo-Ahen OMH, Österbacka R, Eriksson JE, Willför S, Petre I, Peltonen J, Leino R, Johnson M, Rosenholm J, Sandler N. Tailored Approaches in Drug Development and Diagnostics: From Molecular Design to Biological Model Systems. Adv Healthc Mater 2017; 6. [PMID: 28892296 DOI: 10.1002/adhm.201700258] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 05/04/2017] [Indexed: 12/13/2022]
Abstract
Approaches to increase the efficiency in developing drugs and diagnostics tools, including new drug delivery and diagnostic technologies, are needed for improved diagnosis and treatment of major diseases and health problems such as cancer, inflammatory diseases, chronic wounds, and antibiotic resistance. Development within several areas of research ranging from computational sciences, material sciences, bioengineering to biomedical sciences and bioimaging is needed to realize innovative drug development and diagnostic (DDD) approaches. Here, an overview of recent progresses within key areas that can provide customizable solutions to improve processes and the approaches taken within DDD is provided. Due to the broadness of the area, unfortunately all relevant aspects such as pharmacokinetics of bioactive molecules and delivery systems cannot be covered. Tailored approaches within (i) bioinformatics and computer-aided drug design, (ii) nanotechnology, (iii) novel materials and technologies for drug delivery and diagnostic systems, and (iv) disease models to predict safety and efficacy of medicines under development are focused on. Current developments and challenges ahead are discussed. The broad scope reflects the multidisciplinary nature of the field of DDD and aims to highlight the convergence of biological, pharmaceutical, and medical disciplines needed to meet the societal challenges of the 21st century.
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Affiliation(s)
- Cecilia Sahlgren
- Faculty of Science and Engineering; Cell Biology; Åbo Akademi University; FI-20520 Turku Finland
- Turku Centre for Biotechnology; Åbo Akademi University and University of Turku; FI-20520 Turku Finland
- Department of Biomedical Engineering; Technical University of Eindhoven; 5613 DR Eindhoven Netherlands
| | - Annika Meinander
- Faculty of Science and Engineering; Cell Biology; Åbo Akademi University; FI-20520 Turku Finland
| | - Hongbo Zhang
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Fang Cheng
- Faculty of Science and Engineering; Cell Biology; Åbo Akademi University; FI-20520 Turku Finland
| | - Maren Preis
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Chunlin Xu
- Faculty of Science and Engineering; Natural Materials Technology; Åbo Akademi University; FI-20500 Turku Finland
| | - Tiina A. Salminen
- Faculty of Science and Engineering; Structural Bioinformatics Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Diana Toivola
- Faculty of Science and Engineering; Cell Biology; Åbo Akademi University; FI-20520 Turku Finland
- Turku Center for Disease Modeling; University of Turku; FI-20520 Turku Finland
| | - Daniel Abankwa
- Department of Biomedical Engineering; Technical University of Eindhoven; 5613 DR Eindhoven Netherlands
| | - Ari Rosling
- Faculty of Science and Engineering; Polymer Technologies; Åbo Akademi University; FI-20500 Turku Finland
| | - Didem Şen Karaman
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Outi M. H. Salo-Ahen
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
- Faculty of Science and Engineering; Structural Bioinformatics Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Ronald Österbacka
- Faculty of Science and Engineering; Physics; Åbo Akademi University; FI-20500 Turku Finland
| | - John E. Eriksson
- Faculty of Science and Engineering; Cell Biology; Åbo Akademi University; FI-20520 Turku Finland
- Turku Centre for Biotechnology; Åbo Akademi University and University of Turku; FI-20520 Turku Finland
| | - Stefan Willför
- Faculty of Science and Engineering; Natural Materials Technology; Åbo Akademi University; FI-20500 Turku Finland
| | - Ion Petre
- Faculty of Science and Engineering; Computer Science; Åbo Akademi University; FI-20500 Turku Finland
| | - Jouko Peltonen
- Faculty of Science and Engineering; Physical Chemistry; Åbo Akademi University; FI-20500 Turku Finland
| | - Reko Leino
- Faculty of Science and Engineering; Organic Chemistry; Johan Gadolin Process Chemistry Centre; Åbo Akademi University; FI-20500 Turku Finland
| | - Mark Johnson
- Faculty of Science and Engineering; Structural Bioinformatics Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Jessica Rosenholm
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Niklas Sandler
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
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14
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Sahlgren C, Meinander A, Zhang H, Cheng F, Preis M, Xu C, Salminen TA, Toivola D, Abankwa D, Rosling A, Karaman DŞ, Salo-Ahen OMH, Österbacka R, Eriksson JE, Willför S, Petre I, Peltonen J, Leino R, Johnson M, Rosenholm J, Sandler N. Tailored Approaches in Drug Development and Diagnostics: From Molecular Design to Biological Model Systems. Adv Healthc Mater 2017. [DOI: 10.1002/adhm.201700258 10.1002/adhm.201700258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Affiliation(s)
- Cecilia Sahlgren
- Faculty of Science and Engineering; Cell Biology; Åbo Akademi University; FI-20520 Turku Finland
- Turku Centre for Biotechnology; Åbo Akademi University and University of Turku; FI-20520 Turku Finland
- Department of Biomedical Engineering; Technical University of Eindhoven; 5613 DR Eindhoven Netherlands
| | - Annika Meinander
- Faculty of Science and Engineering; Cell Biology; Åbo Akademi University; FI-20520 Turku Finland
| | - Hongbo Zhang
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Fang Cheng
- Faculty of Science and Engineering; Cell Biology; Åbo Akademi University; FI-20520 Turku Finland
| | - Maren Preis
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Chunlin Xu
- Faculty of Science and Engineering; Natural Materials Technology; Åbo Akademi University; FI-20500 Turku Finland
| | - Tiina A. Salminen
- Faculty of Science and Engineering; Structural Bioinformatics Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Diana Toivola
- Faculty of Science and Engineering; Cell Biology; Åbo Akademi University; FI-20520 Turku Finland
- Turku Center for Disease Modeling; University of Turku; FI-20520 Turku Finland
| | - Daniel Abankwa
- Department of Biomedical Engineering; Technical University of Eindhoven; 5613 DR Eindhoven Netherlands
| | - Ari Rosling
- Faculty of Science and Engineering; Polymer Technologies; Åbo Akademi University; FI-20500 Turku Finland
| | - Didem Şen Karaman
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Outi M. H. Salo-Ahen
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
- Faculty of Science and Engineering; Structural Bioinformatics Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Ronald Österbacka
- Faculty of Science and Engineering; Physics; Åbo Akademi University; FI-20500 Turku Finland
| | - John E. Eriksson
- Faculty of Science and Engineering; Cell Biology; Åbo Akademi University; FI-20520 Turku Finland
- Turku Centre for Biotechnology; Åbo Akademi University and University of Turku; FI-20520 Turku Finland
| | - Stefan Willför
- Faculty of Science and Engineering; Natural Materials Technology; Åbo Akademi University; FI-20500 Turku Finland
| | - Ion Petre
- Faculty of Science and Engineering; Computer Science; Åbo Akademi University; FI-20500 Turku Finland
| | - Jouko Peltonen
- Faculty of Science and Engineering; Physical Chemistry; Åbo Akademi University; FI-20500 Turku Finland
| | - Reko Leino
- Faculty of Science and Engineering; Organic Chemistry; Johan Gadolin Process Chemistry Centre; Åbo Akademi University; FI-20500 Turku Finland
| | - Mark Johnson
- Faculty of Science and Engineering; Structural Bioinformatics Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Jessica Rosenholm
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
| | - Niklas Sandler
- Faculty of Science and Engineering; Pharmaceutical Sciences Laboratory; Åbo Akademi University; FI-20520 Turku Finland
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15
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Gullmets J, Torvaldson E, Lindqvist J, Imanishi SY, Taimen P, Meinander A, Eriksson JE. Internal epithelia in Drosophila display rudimentary competence to form cytoplasmic networks of transgenic human vimentin. FASEB J 2017; 31:5332-5341. [PMID: 28778974 DOI: 10.1096/fj.201700332r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/25/2017] [Indexed: 11/11/2022]
Abstract
Cytoplasmic intermediate filaments (cIFs) are found in all eumetazoans, except arthropods. To investigate the compatibility of cIFs in arthropods, we expressed human vimentin (hVim), a cIF with filament-forming capacity in vertebrate cells and tissues, transgenically in Drosophila Transgenic hVim could be recovered from whole-fly lysates by using a standard procedure for intermediate filament (IF) extraction. When this procedure was used to test for the possible presence of IF-like proteins in flies, only lamins and tropomyosin were observed in IF-enriched extracts, thereby providing biochemical reinforcement to the paradigm that arthropods lack cIFs. In Drosophila, transgenic hVim was unable to form filament networks in S2 cells and mesenchymal tissues; however, cage-like vimentin structures could be observed around the nuclei in internal epithelia, which suggests that Drosophila retains selective competence for filament formation. Taken together, our results imply that although the filament network formation competence is partially lost in Drosophila, a rudimentary filament network formation ability remains in epithelial cells. As a result of the observed selective competence for cIF assembly in Drosophila, we hypothesize that internal epithelial cIFs were the last cIFs to disappear from arthropods.-Gullmets, J., Torvaldson, E., Lindqvist, J., Imanishi, S. Y., Taimen, P., Meinander, A., Eriksson, J. E. Internal epithelia in Drosophila display rudimentary competence to form cytoplasmic networks of transgenic human vimentin.
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Affiliation(s)
- Josef Gullmets
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland.,Department of Pathology, University of Turku and Turku University Hospital, Turku, Finland.,MediCity Research Laboratory, Turku, Finland
| | - Elin Torvaldson
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Julia Lindqvist
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Susumu Y Imanishi
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
| | - Pekka Taimen
- Department of Pathology, University of Turku and Turku University Hospital, Turku, Finland.,MediCity Research Laboratory, Turku, Finland
| | - Annika Meinander
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - John E Eriksson
- Cell Biology, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland; .,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
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16
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Toivonen HT, Meinander A, Asaoka T, Westerlund M, Pettersson F, Mikhailov A, Eriksson JE, Saxén H. Modeling reveals that dynamic regulation of c-FLIP levels determines cell-to-cell distribution of CD95-mediated apoptosis. J Biol Chem 2011; 286:18375-82. [PMID: 21324892 PMCID: PMC3099654 DOI: 10.1074/jbc.m110.177097] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 02/11/2011] [Indexed: 12/22/2022] Open
Abstract
The expression levels of caspase-8 inhibitory c-FLIP proteins play an important role in regulating death receptor-mediated apoptosis, as their concentration at the moment when the death-inducing signaling complex (DISC) is formed determines the outcome of the DISC signal. Experimental studies have shown that c-FLIP proteins are subject to dynamic turnover and that their stability and expression levels can be rapidly altered. Even though the influence of c-FLIP on the apoptotic behavior of a single cell has been captured in mathematical simulation studies, the effect of c-FLIP turnover and stability has not been investigated. In this study, a mathematical model of apoptosis was developed to analyze how the dynamic turnover and stability of the c-FLIP isoforms regulate apoptotic signaling for both individual cells and cell populations. Intercellular parameter and concentration distributions were used to describe the behavior of cell populations. Monte-Carlo simulations of cell populations showed that c-FLIP turnover is a key determinant of death receptor responses. The fact that the developed model simulates the state of whole cell populations makes it possible to validate it by comparison with empirical data. The proposed modeling approach can be used to further determine limiting factors in the DISC signaling process.
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Affiliation(s)
| | | | - Tomoko Asaoka
- Biosciences and
- Turku Centre for Biotechnology, Åbo Akademi University and University of Turku, FI-20520 Turku, Finland
| | | | - Frank Pettersson
- Chemical Engineering, Åbo Akademi University, FI-20500 Turku, Finland and
| | | | - John E. Eriksson
- Biosciences and
- Turku Centre for Biotechnology, Åbo Akademi University and University of Turku, FI-20520 Turku, Finland
| | - Henrik Saxén
- Chemical Engineering, Åbo Akademi University, FI-20500 Turku, Finland and
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17
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Blom T, Bergelin N, Meinander A, Löf C, Slotte JP, Eriksson JE, Törnquist K. An autocrine sphingosine-1-phosphate signaling loop enhances NF-kappaB-activation and survival. BMC Cell Biol 2010; 11:45. [PMID: 20573281 PMCID: PMC2906432 DOI: 10.1186/1471-2121-11-45] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 06/24/2010] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Sphingosine-1-phosphate (S1P) is a bioactive lipid that regulates a multitude of cellular functions, including cell proliferation, survival, migration and angiogenesis. S1P mediates its effects either by signaling through G protein-coupled receptors (GPCRs) or through an intracellular mode of action. In this study, we have investigated the mechanism behind S1P-induced survival signalling. RESULTS We found that S1P protected cells from FasL-induced cell death in an NF-kappaB dependent manner. NF-kappaB was activated by extracellular S1P via S1P2 receptors and Gi protein signaling. Our study also demonstrates that extracellular S1P stimulates cells to rapidly produce and secrete additional S1P, which can further amplify the NF-kappaB activation. CONCLUSIONS We propose a self-amplifying loop of autocrine S1P with capacity to enhance cell survival. The mechanism provides increased understanding of the multifaceted roles of S1P in regulating cell fate during normal development and carcinogenesis.
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Affiliation(s)
- Tomas Blom
- Department of Biology, Abo Akademi University, 20520 Turku, Finland
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18
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Rosenholm JM, Meinander A, Peuhu E, Niemi R, Eriksson JE, Sahlgren C, Lindén M. Targeting of porous hybrid silica nanoparticles to cancer cells. ACS Nano 2009; 3:197-206. [PMID: 19206267 DOI: 10.1021/nn800781r] [Citation(s) in RCA: 277] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Mesoporous silica nanoparticles functionalized by surface hyperbranching polymerization of poly(ethylene imine), PEI, were further modified by introducing both fluorescent and targeting moieties, with the aim of specifically targeting cancer cells. Owing to the high abundance of folate receptors in many cancer cells as compared to normal cells, folic acid was used as the targeting ligand. The internalization of the particles in cell lines expressing different levels of folate receptors was studied. Flow cytometry was used to quantify the mean number of nanoparticles internalized per cell. Five times more particles were internalized by cancer cells expressing folate receptors as compared to the normal cells expressing low levels of the receptor. Not only the number of nanoparticles internalized per cell, but also the fraction of cells that had internalized nanoparticles was higher. The total number of particles internalized by the cancer cells was, therefore, about an order of magnitude higher than the total number of particles internalized by normal cells, a difference high enough to be of significant biological importance. In addition, the biospecifically tagged hybrid PEI-silica particles were shown to be noncytotoxic and able to specifically target folate receptor-expressing cancer cells also under coculture conditions.
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Affiliation(s)
- Jessica M Rosenholm
- Center for Functional Materials, Department of Physical Chemistry, Abo Akademi University, Porthansgatan 3-5, FI-2500 Turku, Finland
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19
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Elphick LM, Hawat M, Toms NJ, Meinander A, Mikhailov A, Eriksson JE, Kass GEN. Opposing roles for caspase and calpain death proteases in L-glutamate-induced oxidative neurotoxicity. Toxicol Appl Pharmacol 2008; 232:258-67. [PMID: 18687350 DOI: 10.1016/j.taap.2008.07.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 06/30/2008] [Accepted: 07/01/2008] [Indexed: 11/25/2022]
Abstract
Oxidative glutamate toxicity in HT22 murine hippocampal cells is a model for neuronal death by oxidative stress. We have investigated the role of proteases in HT22 cell oxidative glutamate toxicity. L-glutamate-induced toxicity was characterized by cell and nuclear shrinkage and chromatin condensation, yet occurred in the absence of either DNA fragmentation or mitochondrial cytochrome c release. Pretreatment with the selective caspase inhibitors either benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (pan-caspase), N-acetyl-Leu-Glu-His-Asp-aldehyde (caspase 9) or N-acetyl-Ile-Glu-Thr-Asp-aldehyde (caspase 8), significantly increased L-glutamate-induced cell death with a corresponding increase in observed nuclear shrinkage and chromatin condensation. This enhancement of glutamate toxicity correlated with an increase in L-glutamate-dependent production of reactive oxygen species (ROS) as a result of caspase inhibition. Pretreating the cells with N-acetyl-L-cysteine prevented ROS production, cell shrinkage and cell death from L-glutamate as well as that associated with the presence of the pan-caspase inhibitor. In contrast, the caspase-3/-7 inhibitor N-acetyl-Asp-Glu-Val-Asp aldehyde was without significant effect. However, pretreating the cells with the calpain inhibitor N-acetyl-Leu-Leu-Nle-CHO, but not the cathepsin B inhibitor CA-074, prevented cell death. The cytotoxic role of calpains was confirmed further by: 1) cytotoxic dependency on intracellular Ca(2+) increase, 2) increased cleavage of the calpain substrate Suc-Leu-Leu-Val-Tyr-AMC and 3) immunoblot detection of the calpain-selective 145 kDa alpha-fodrin cleavage fragment. We conclude that oxidative L-glutamate toxicity in HT22 cells is mediated via calpain activation, whereas inhibition of caspases-8 and -9 may exacerbate L-glutamate-induced oxidative neuronal damage through increased oxidative stress.
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Affiliation(s)
- Lucy M Elphick
- Division of Biochemical Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK
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20
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Meinander A, Söderström TS, Kaunisto A, Poukkula M, Sistonen L, Eriksson JE. Fever-like hyperthermia controls T Lymphocyte persistence by inducing degradation of cellular FLIPshort. J Immunol 2007; 178:3944-53. [PMID: 17339495 DOI: 10.4049/jimmunol.178.6.3944] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Fever has a major impact on immune responses by modulating survival, proliferation, and endurance of lymphocytes. Lymphocyte persistence in turn is determined by the equilibrium between death and survival-promoting factors that regulate death receptor signaling in these cells. A potential integrator of death receptor signaling is the caspase-8 inhibitor c-FLIP, the expression of which is dynamically regulated, either rapidly induced or down-regulated. In this study, we show in activated primary human T lymphocytes that hyperthermia corresponding to fever triggered down-regulation of both c-FLIP-splicing variants, c-FLIPshort (c-FLIP(S)) and c-FLIPlong, with consequent sensitization to apoptosis mediated by CD95 (Fas/APO-1). The c-FLIP down-regulation and subsequent sensitization was specific for hyperthermic stress. Additionally, we show that the hyperthermia-mediated down-regulation was due to increased ubiquitination and proteasomal degradation of c-FLIP(S), the stability of which we have shown to be regulated by its C-terminal splicing tail. Furthermore, the induced sensitivity to CD95 ligation was independent of heat shock protein 70, as thermotolerant cells, expressing substantially elevated levels of heat shock protein 70, were not rescued from the effect of hyperthermia-mediated c-FLIP down-regulation. Our findings indicate that fever significantly influences the rate of lymphocyte elimination through depletion of c-FLIP(S). Such a general regulatory mechanism for lymphocyte removal has broad ramifications for fever-mediated regulation of immune responses.
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Affiliation(s)
- Annika Meinander
- Turku Centre for Biotechnology, Abo Akademi University and University of Turku, FI-20521 Turku, Finland
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21
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Elphick LM, Meinander A, Mikhailov A, Richard M, Toms NJ, Eriksson JE, Kass GEN. Live cell detection of caspase-3 activation by a Discosoma-red-fluorescent-protein-based fluorescence resonance energy transfer construct. Anal Biochem 2006; 349:148-55. [PMID: 16386699 DOI: 10.1016/j.ab.2005.11.031] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2005] [Revised: 10/26/2005] [Accepted: 11/21/2005] [Indexed: 11/29/2022]
Abstract
A probe consisting of Discosoma red fluorescent protein (DsRed) and enhanced yellow fluorescent protein (EYFP) linked by a 19-amino-acid chain containing the caspase-3 cleavage site Asp-Glu-Val-Asp was developed to monitor caspase-3 activation in living cells. The expression of the tandem construct in mammalian cells yielded a strong red fluorescence when excited with 450- to 490-nm light or with a 488-nm argon ion laser line as a result of fluorescence resonance energy transfer (FRET) from donor EYFP to acceptor DsRed. The advantage over previous constructs using cyan fluorescent protein is that our construct can be used when excitation wavelengths lower than 488nm are not available. To validate the construct, murine HT-22 hippocampal neuronal cells were triggered to undergo CD95-induced neuronal death. An increase in caspase-3 activity was demonstrated by a reduction of FRET in cells transfected with the construct. This was manifested by a dequenching of EYFP fluorescence leading to an increase in EYFP emission and a corresponding decrease in DsRed fluorescence, which correlated with an increase in pro-caspase-3 processing. We conclude that CD95-induced caspase-3 activation in HT-22 cells was readily detected at the single-cell level using the DsRed-EYFP-based FRET construct, making this a useful technology to monitor caspase-3 activity in living cells.
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Affiliation(s)
- Lucy M Elphick
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford GU2 7XH, UK
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22
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Abstract
Transcription-independent modulation of signaling mediated by death receptors (DRs) has emerged as an important determinant of cell survival during both development and cellular homeostasis. Frequently, a given DR signal must be redirected rapidly either to inhibit or to potentiate the apoptotic response. This process requires immediate, protein-synthesis-independent modifications of the regulatory molecules involved. Numerous mechanisms have been shown to regulate DR responses without engaging the apoptosis-directing transcription machinery. These mechanisms involve key posttranslational modifications such as phosphorylation, ubiquitination and proteolytic degradation, all of which affect the activities of proteins at different levels in the DR signaling pathways. Changes in the organization of regulatory molecules and in their interactions with other factors also affect the DR signaling pathways. The balance between these modulatory signals rapidly decides the fate of a cell.
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Affiliation(s)
- Stefanie E F Tran
- Institut de Génétique Moléculaire et Cellulaire de Montpellier, CNRS UMR 5535, 1919 route de Mende, 34293 Montpellier, France
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23
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Härmälä-Braskén AS, Mikhailov A, Söderström TS, Meinander A, Holmström TH, Damuni Z, Eriksson JE. Type-2A protein phosphatase activity is required to maintain death receptor responsiveness. Oncogene 2003; 22:7677-86. [PMID: 14576831 DOI: 10.1038/sj.onc.1207077] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Type-2A protein phosphatase (PP2A) is a key regulator in many different cell signaling pathways and an important determinant in tumorigenesis. One of the signaling targets of PP2A is the mitogen-activated protein kinase (MAPK/ERK) cascade. In this study, we wanted to determine whether PP2A could be involved in regulation of death receptor activity through its capacity to regulate MAPK/ERK. To this end, we studied the effects of two different routes of protein phosphatase inhibition on death receptor-mediated apoptosis. We demonstrated that the apoptosis mediated by Fas, TNF-alpha, and TRAIL in U937 cells is suppressed by calyculin A, an inhibitor of type-1 and type-2A protein phosphatases. The inhibition of the protein phosphatase activity was shown to subsequently increase the MAPK activity in these cells, and the level of activation corresponded to the degree of suppression of cytokine-mediated apoptosis. A more physiological inhibitor, the intracellular PP2A inhibitor protein I2(PP2A), protected transfected HeLa cells in a similar way from Fas-mediated apoptosis and induced activation of MAPK in I2(PP2A) transfected cells. A corresponding inhibition could also be obtained by stable transfection with a constitutively active form of the MAPK kinase, MKK1 (also referred to as MEK1). The inhibitor-mediated protection was highly efficient in preventing early stages of apoptosis, as no caspase-8 cleavage occurred in these cells. The observed apoptosis suppression is likely to facilitate the tumor-promoting effect of a range of different type-2A protein phosphatase inhibitors, and could explain the reported tumor association of I2(PP2A).
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Affiliation(s)
- Ann-Sofi Härmälä-Braskén
- Turku Centre for Biotechnology, University of Turku, Abo Akademi University, POB 123, Turku FIN-20521, Finland
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24
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Tran SEF, Meinander A, Holmström TH, Rivero-Müller A, Heiskanen KM, Linnau EK, Courtney MJ, Mosser DD, Sistonen L, Eriksson JE. Heat stress downregulates FLIP and sensitizes cells to Fas receptor-mediated apoptosis. Cell Death Differ 2003; 10:1137-47. [PMID: 14502237 DOI: 10.1038/sj.cdd.4401278] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The heat shock response and death receptor-mediated apoptosis are both key physiological determinants of cell survival. We found that exposure to a mild heat stress rapidly sensitized Jurkat and HeLa cells to Fas-mediated apoptosis. We further demonstrate that Hsp70 and the mitogen-activated protein kinases, critical molecules involved in both stress-associated and apoptotic responses, are not responsible for the sensitization. Instead, heat stress on its own induced downregulation of FLIP and promoted caspase-8 cleavage without triggering cell death, which might be the cause of the observed sensitization. Since caspase-9 and -3 were not cleaved after heat shock, caspase-8 seemed to be the initial caspase activated in the process. These findings could help understanding the regulation of death receptor signaling during stress, fever, or inflammation.
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Affiliation(s)
- S E F Tran
- Turku Centre for Biotechnology, Department of Biology, Abo Akademi University and University of Turku, Turku, Finland
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25
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Holmberg CI, Hietakangas V, Mikhailov A, Rantanen JO, Kallio M, Meinander A, Hellman J, Morrice N, MacKintosh C, Morimoto RI, Eriksson JE, Sistonen L. Phosphorylation of serine 230 promotes inducible transcriptional activity of heat shock factor 1. EMBO J 2001; 20:3800-10. [PMID: 11447121 PMCID: PMC125548 DOI: 10.1093/emboj/20.14.3800] [Citation(s) in RCA: 224] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Heat shock factor 1 (HSF1) is a serine-rich constitutively phosphorylated mediator of the stress response. Upon stress, HSF1 forms DNA-binding trimers, relocalizes to nuclear granules, undergoes inducible phosphorylation and acquires the properties of a transactivator. HSF1 is phosphorylated on multiple sites, but the sites and their function have remained an enigma. Here, we have analyzed sites of endogenous phosphorylation on human HSF1 and developed a phosphopeptide antibody to identify Ser230 as a novel in vivo phosphorylation site. Ser230 is located in the regulatory domain of HSF1, and promotes the magnitude of the inducible transcriptional activity. Ser230 lies within a consensus site for calcium/calmodulin-dependent protein kinase II (CaMKII), and CaMKII overexpression enhances both the level of in vivo Ser230 phosphorylation and transactivation of HSF1. The importance of Ser230 was further established by the S230A HSF1 mutant showing markedly reduced activity relative to wild-type HSF1 when expressed in hsf1(-/-) cells. Our study provides the first evidence that phosphorylation is essential for the transcriptional activity of HSF1, and hence for induction of the heat shock response.
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Affiliation(s)
- Carina I. Holmberg
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Ville Hietakangas
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Andrey Mikhailov
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Jouni O. Rantanen
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Marko Kallio
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Annika Meinander
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Jukka Hellman
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Nick Morrice
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Carol MacKintosh
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Richard I. Morimoto
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - John E. Eriksson
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
| | - Lea Sistonen
- Turku Centre for Biotechnology, University of Turku, Åbo Akademi University, Department of Biochemistry and Food Chemistry and Department of Biology, University of Turku, Department of Biology, Åbo Akademi University, Finland, MRC Protein Phosphorylation Unit, Department of Biochemistry, University of Dundee, UK and Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, IL, USA Corresponding author at Turku Centre for Biotechnology, PO Box 123, FIN-20521 Turku, Finland e-mail:
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