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Vig S, Lambooij JM, Dekkers MC, Otto F, Carlotti F, Guigas B, Zaldumbide A. ER stress promotes mitochondrial DNA mediated type-1 interferon response in beta-cells and interleukin-8 driven neutrophil chemotaxis. Front Endocrinol (Lausanne) 2022; 13:991632. [PMID: 36171907 PMCID: PMC9511040 DOI: 10.3389/fendo.2022.991632] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/19/2022] [Indexed: 11/21/2022] Open
Abstract
Beta-cell destruction in type 1 diabetes (T1D) results from the combined effect of inflammation and recurrent autoimmunity. Accumulating evidence suggests the engagement of cellular stress during the initial stage of the disease, preceding destruction and triggering immune cell infiltration. While the role of the endoplasmic reticulum (ER) in this process has been largely described, the participation of the other cellular organelles, particularly the mitochondria which are central mediator for beta-cell survival and function, remains poorly investigated. Here, we have explored the contribution of ER stress, in activating type-I interferon signaling and innate immune cell recruitment. Using human beta-cell line EndoC-βH1 exposed to thapsigargin, we demonstrate that induction of cellular stress correlates with mitochondria dysfunction and a significant accumulation of cytosolic mitochondrial DNA (mtDNA) that triggers neutrophils migration by an IL8-dependent mechanism. These results provide a novel mechanistic insight on how ER stress can cause insulitis and may ultimately facilitate the identification of potential targets to protect beta-cells against immune infiltration.
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Affiliation(s)
- Saurabh Vig
- Department of Cell and Chemical Biology Leiden University Medical Center, Leiden, Netherlands
- *Correspondence: Arnaud Zaldumbide, ; Saurabh Vig,
| | - Joost M. Lambooij
- Department of Cell and Chemical Biology Leiden University Medical Center, Leiden, Netherlands
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Mette C. Dekkers
- Department of Cell and Chemical Biology Leiden University Medical Center, Leiden, Netherlands
| | - Frank Otto
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Françoise Carlotti
- Department of Internal Medicine, Leiden University Medical Center, Leiden, Netherlands
| | - Bruno Guigas
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Arnaud Zaldumbide
- Department of Cell and Chemical Biology Leiden University Medical Center, Leiden, Netherlands
- *Correspondence: Arnaud Zaldumbide, ; Saurabh Vig,
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Caruana M, Camilleri A, Farrugia MY, Ghio S, Jakubíčková M, Cauchi RJ, Vassallo N. Extract from the Marine Seaweed Padina pavonica Protects Mitochondrial Biomembranes from Damage by Amyloidogenic Peptides. Molecules 2021; 26:1444. [PMID: 33799979 PMCID: PMC7962105 DOI: 10.3390/molecules26051444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 11/30/2022] Open
Abstract
The identification of compounds which protect the double-membrane of mitochondrial organelles from disruption by toxic confomers of amyloid proteins may offer a therapeutic strategy to combat human neurodegenerative diseases. Here, we exploited an extract from the marine brown seaweed Padina pavonica (PPE) as a vital source of natural bioactive compounds to protect mitochondrial membranes against insult by oligomeric aggregates of the amyloidogenic proteins amyloid-β (Aβ), α-synuclein (α-syn) and tau, which are currently considered to be major targets for drug discovery in Alzheimer's disease (AD) and Parkinson's disease (PD). We show that PPE manifested a significant inhibitory effect against swelling of isolated mitochondria exposed to the amyloid oligomers, and attenuated the release of cytochrome c from the mitochondria. Using cardiolipin-enriched synthetic lipid membranes, we also show that dye leakage from fluorophore-loaded vesicles and formation of channel-like pores in planar bilayer membranes are largely prevented by incubating the oligomeric aggregates with PPE. Lastly, we demonstrate that PPE curtails the ability of Aβ42 and α-syn monomers to self-assemble into larger β-aggregate structures, as well as potently disrupts their respective amyloid fibrils. In conclusion, the mito-protective and anti-aggregator biological activities of Padina pavonica extract may be of therapeutic value in neurodegenerative proteinopathies, such as AD and PD.
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Affiliation(s)
- Mario Caruana
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, 2023 Msida, Malta; (M.C.); (A.C.); (M.Y.F.); (S.G.); (M.J.); (R.J.C.)
- Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, 2023 Msida, Malta
| | - Angelique Camilleri
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, 2023 Msida, Malta; (M.C.); (A.C.); (M.Y.F.); (S.G.); (M.J.); (R.J.C.)
- Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, 2023 Msida, Malta
| | - Maria Ylenia Farrugia
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, 2023 Msida, Malta; (M.C.); (A.C.); (M.Y.F.); (S.G.); (M.J.); (R.J.C.)
- Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, 2023 Msida, Malta
| | - Stephanie Ghio
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, 2023 Msida, Malta; (M.C.); (A.C.); (M.Y.F.); (S.G.); (M.J.); (R.J.C.)
- Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, 2023 Msida, Malta
| | - Michaela Jakubíčková
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, 2023 Msida, Malta; (M.C.); (A.C.); (M.Y.F.); (S.G.); (M.J.); (R.J.C.)
- Department of Experimental Biology, Faculty of Science, Masaryk University, 60300 Brno, Czech Republic
| | - Ruben J. Cauchi
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, 2023 Msida, Malta; (M.C.); (A.C.); (M.Y.F.); (S.G.); (M.J.); (R.J.C.)
- Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, 2023 Msida, Malta
| | - Neville Vassallo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, 2023 Msida, Malta; (M.C.); (A.C.); (M.Y.F.); (S.G.); (M.J.); (R.J.C.)
- Centre for Molecular Medicine and Biobanking, Biomedical Sciences Building, University of Malta, 2023 Msida, Malta
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3
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Farrugia MY, Caruana M, Ghio S, Camilleri A, Farrugia C, Cauchi RJ, Cappelli S, Chiti F, Vassallo N. Toxic oligomers of the amyloidogenic HypF-N protein form pores in mitochondrial membranes. Sci Rep 2020; 10:17733. [PMID: 33082392 PMCID: PMC7575562 DOI: 10.1038/s41598-020-74841-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 10/06/2020] [Indexed: 12/30/2022] Open
Abstract
Studies on the amyloidogenic N-terminal domain of the E. coli HypF protein (HypF-N) have contributed significantly to a detailed understanding of the pathogenic mechanisms in neurodegenerative diseases characterised by the formation of misfolded oligomers, by proteins such as amyloid-β, α-synuclein and tau. Given that both cell membranes and mitochondria are increasingly recognised as key targets of oligomer toxicity, we investigated the damaging effects of aggregates of HypF-N on mitochondrial membranes. Essentially, we found that HypF-N oligomers characterised by high surface hydrophobicity (type A) were able to trigger a robust permeabilisation of mito-mimetic liposomes possessing cardiolipin-rich membranes and dysfunction of isolated mitochondria, as demonstrated by a combination of mitochondrial shrinking, lowering of mitochondrial membrane potential and cytochrome c release. Furthermore, using single-channel electrophysiology recordings we obtained evidence that the type A aggregates induced currents reflecting formation of ion-conducting pores in mito-mimetic planar phospholipid bilayers, with multi-level conductances ranging in the hundreds of pS at negative membrane voltages. Conversely, HypF-N oligomers with low surface hydrophobicity (type B) could not permeabilise or porate mitochondrial membranes. These results suggest an inherent toxicity of membrane-active aggregates of amyloid-forming proteins to mitochondria, and that targeting of oligomer-mitochondrial membrane interactions might therefore afford protection against such damage.
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Affiliation(s)
- Maria Ylenia Farrugia
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
- Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Mario Caruana
- Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Stephanie Ghio
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
- Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Angelique Camilleri
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
- Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | | | - Ruben J Cauchi
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
- Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Sara Cappelli
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134, Florence, Italy
| | - Fabrizio Chiti
- Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, 50134, Florence, Italy
| | - Neville Vassallo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.
- Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta.
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4
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Camilleri A, Ghio S, Caruana M, Weckbecker D, Schmidt F, Kamp F, Leonov A, Ryazanov S, Griesinger C, Giese A, Cauchi RJ, Vassallo N. Tau-induced mitochondrial membrane perturbation is dependent upon cardiolipin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183064. [PMID: 31521630 DOI: 10.1016/j.bbamem.2019.183064] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 08/26/2019] [Accepted: 09/10/2019] [Indexed: 01/14/2023]
Abstract
Misfolding and aggregate formation by the tau protein has been closely related with neurotoxicity in a large group of human neurodegenerative disorders, which includes Alzheimer's disease. Here, we investigate the membrane-active properties of tau oligomers on mitochondrial membranes, using minimalist in vitro model systems. Thus, exposure of isolated mitochondria to oligomeric tau evoked a disruption of mitochondrial membrane integrity, as evidenced by a combination of organelle swelling, efflux of cytochrome c and loss of the mitochondrial membrane potential. Tau-induced mitochondrial dysfunction occurred independently of the mitochondrial permeability transition (mPT) pore complex. Notably, mitochondria were rescued by pre-incubation with 10-N-nonyl acridine orange (NAO), a molecule that specifically binds cardiolipin (CL), the signature phospholipid of mitochondrial membranes. Additionally, NAO prevented direct binding of tau oligomers to isolated mitochondria. At the same time, tau proteins exhibited high affinity to CL-enriched membranes, whilst permeabilisation of lipid vesicles also strongly correlated with CL content. Intriguingly, using single-channel electrophysiology, we could demonstrate the formation of non-selective ion-conducting tau nanopores exhibiting multilevel conductances in mito-mimetic bilayers. Taken together, the data presented here advances a scenario in which toxic cytosolic entities of tau protein would target mitochondrial organelles by associating with their CL-rich membrane domains, leading to membrane poration and compromised mitochondrial structural integrity.
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Affiliation(s)
- Angelique Camilleri
- Department of Physiology and Biochemistry, Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Stephanie Ghio
- Department of Physiology and Biochemistry, Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Mario Caruana
- Department of Physiology and Biochemistry, Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | | | - Felix Schmidt
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Munich, Germany
| | - Frits Kamp
- Biomedical Center-BMC, Metabolic Biochemistry, Ludwig-Maximilians-University, Munich, Germany
| | - Andrei Leonov
- MODAG GmbH, Wendelsheim, Germany; Department of NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Sergey Ryazanov
- Department of NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Christian Griesinger
- Department of NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Armin Giese
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Munich, Germany
| | - Ruben J Cauchi
- Department of Physiology and Biochemistry, Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Neville Vassallo
- Department of Physiology and Biochemistry, Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta.
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5
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Ghio S, Camilleri A, Caruana M, Ruf VC, Schmidt F, Leonov A, Ryazanov S, Griesinger C, Cauchi RJ, Kamp F, Giese A, Vassallo N. Cardiolipin Promotes Pore-Forming Activity of Alpha-Synuclein Oligomers in Mitochondrial Membranes. ACS Chem Neurosci 2019; 10:3815-3829. [PMID: 31356747 DOI: 10.1021/acschemneuro.9b00320] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aggregation of the amyloid-forming α-synuclein (αS) protein is closely associated with the etiology of Parkinson's disease (PD), the most common motor neurodegenerative disorder. Many studies have shown that soluble aggregation intermediates of αS, termed oligomers, permeabilize a variety of phospholipid membranes; thus, membrane disruption may represent a key pathogenic mechanism of αS toxicity. Given the centrality of mitochondrial dysfunction in PD, we therefore probed the formation of ion-permeable pores by αS oligomers in planar lipid bilayers reflecting the complex phospholipid composition of mitochondrial membranes. Using single-channel electrophysiology, we recorded distinct multilevel conductances (100-400 pS) with stepwise current transitions, typical of protein-bound nanopores, in mitochondrial-like membranes. Crucially, we observed that the presence of cardiolipin (CL), the signature phospholipid of mitochondrial membranes, enhanced αS-lipid interaction and the membrane pore-forming activity of αS oligomers. Further, preincubation of isolated mitochondria with a CL-specific dye protected against αS oligomer-induced mitochondrial swelling and release of cytochrome c. Hence, we favor a scenario in which αS oligomers directly porate a local lipid environment rich in CL, for instance outer mitochondrial contact sites or the inner mitochondrial membrane, to induce mitochondrial dysfunction. Pharmacological modulation of αS pore complex formation might thus preserve mitochondrial membrane integrity and alleviate mitochondrial dysfunction in PD.
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Affiliation(s)
- Stephanie Ghio
- Department of Physiology and Biochemistry and Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Angelique Camilleri
- Department of Physiology and Biochemistry and Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Mario Caruana
- Department of Physiology and Biochemistry and Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Viktoria C. Ruf
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Munich, Germany
| | - Felix Schmidt
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Munich, Germany
| | - Andrei Leonov
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Sergey Ryazanov
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- MODAG GmbH, Wendelsheim, Germany
| | - Christian Griesinger
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ruben J. Cauchi
- Department of Physiology and Biochemistry and Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Frits Kamp
- Biomedical Center, Metabolic Biochemistry, Ludwig-Maximilians-University, Munich, Germany
| | - Armin Giese
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Munich, Germany
| | - Neville Vassallo
- Department of Physiology and Biochemistry and Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
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6
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Quintana DD, Garcia JA, Sarkar SN, Jun S, Engler-Chiurazzi EB, Russell AE, Cavendish JZ, Simpkins JW. Hypoxia-reoxygenation of primary astrocytes results in a redistribution of mitochondrial size and mitophagy. Mitochondrion 2019; 47:244-255. [PMID: 30594729 PMCID: PMC6980114 DOI: 10.1016/j.mito.2018.12.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 08/07/2018] [Accepted: 12/18/2018] [Indexed: 12/15/2022]
Abstract
Astrocytes serve to maintain proper neuronal function and support neuronal viability, but remain largely understudied in research of cerebral ischemia. Astrocytic mitochondria are core participants in the metabolic activity of astrocytes. The objective of this study is to assess astrocyte mitochondrial competence during hypoxia and post-hypoxia reoxygenation and to determine cellular adaptive and pathological changes in the mitochondrial network. We hypothesize that during metabolic distress in astrocytes; mitochondrial networks undergo a shift in fission-fusion dynamics that results in a change in the morphometric state of the entire mitochondrial network. This mitochondrial network shift may be protective during metabolic distress by priming mitochondrial size and facilitating mitophagy. We demonstrated that hypoxia and post-hypoxia reoxygenation of rat primary astrocytes results in a redistribution of mitochondria to smaller sizes evoked by increased mitochondrial fission. Excessive mitochondrial fission corresponded to Drp-1 dephosphorylation at Ser 637, which preceded mitophagy of relatively small mitochondria. Reoxygenation of astrocytes marked the initiation of elevated mitophagic activity primarily reserved to the perinuclear region where a large number of the smallest mitochondria occurred. Although, during hypoxia astrocytic ATP content was severely reduced, after reoxygenation ATP content returned to near normoxic values and these changes mirrored mitochondrial superoxide production. Concomitant with these changes in astrocytic mitochondria, the number of astrocytic extensions declined only after 10-hours post-hypoxic reoxygenation. Overall, we posit a drastic mitochondrial network change that is triggered by a metabolic crisis during hypoxia; these changes are followed by mitochondrial degradation and retraction of astrocytic extensions during reoxygenation.
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Affiliation(s)
- Dominic D Quintana
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - Jorge A Garcia
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - Saumyendra N Sarkar
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - Sujung Jun
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - Elizabeth B Engler-Chiurazzi
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - Ashley E Russell
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - John Z Cavendish
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - James W Simpkins
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States.
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Fujii S, Muraoka S, Miyamoto A, Sakurai K. [Linezolid-induced Apoptosis through Mitochondrial Damage and Role of Superoxide Dismutase-1 in Human Monocytic Cell Line U937]. YAKUGAKU ZASSHI 2018; 138:73-81. [PMID: 29311467 DOI: 10.1248/yakushi.17-00133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cytopenia is a major adverse event associated with linezolid therapy. The objective of this study was to examine whether the cytotoxicity of linezolid to eukaryotic cells was associated with mitochondrial dysfunction and apoptosis-like cell death in human leukemic monocyte lymphoma cell line U937. Apoptosis-like cell death was clearly observed when cells were incubated with linezolid, depending on the duration and linezolid concentration. Mitochondrial membrane potential of cells treated with linezolid collapsed in a short period of time, but the number of mitochondria did not decrease. Cytotoxicity of linezolid was relieved by the knockdown of superoxide dismutase-1 in U937 cells. On the other hand, no autophagy was observed in cells treated with linezolid. These results suggest that mitochondrial damages would be linked to the induction of apoptosis in U937 cells treated with linezolid and that its mechanism does not involve autophagy.
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Affiliation(s)
- Satoshi Fujii
- Department of Hospital Pharmacy, Sapporo Medical University Hospital.,Department of Life Science, Hokkaido Pharmaceutical University School of Pharmacy
| | - Sanae Muraoka
- Department of Life Science, Hokkaido Pharmaceutical University School of Pharmacy
| | - Atsushi Miyamoto
- Department of Hospital Pharmacy, Sapporo Medical University Hospital
| | - Koichi Sakurai
- Department of Life Science, Hokkaido Pharmaceutical University School of Pharmacy
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8
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Protective Effect of Intravenous High Molecular Weight Polyethylene Glycol on Fatty Liver Preservation. BIOMED RESEARCH INTERNATIONAL 2015; 2015:794287. [PMID: 26543868 PMCID: PMC4620277 DOI: 10.1155/2015/794287] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/08/2015] [Accepted: 08/12/2015] [Indexed: 12/17/2022]
Abstract
Ischemia reperfusion injury (IRI) leads to significant tissue damage in liver surgery. Polyethylene glycols (PEGs) are water soluble nontoxic polymers that have proved their effectiveness against IRI. The objective of our study was to investigate the potential protective effects of intravenous administration of a high molecular weight PEG of 35 kDa (PEG 35) in steatotic livers subjected to cold ischemia reperfusion. In this study, we used isolated perfused rat liver model to assess the effects of PEG 35 intravenous administration after prolonged cold ischemia (24 h, 4°C) and after reperfusion (2 h, 37°C). Liver injury was measured by transaminases levels and mitochondrial damage was determined by confocal microscopy assessing mitochondrial polarization (after cold storage) and by measuring glutamate dehydrogenase activity (after reperfusion). Also, cell signaling pathways involved in the physiopathology of IRI were assessed by western blot technique. Our results show that intravenous administration of PEG 35 at 10 mg/kg ameliorated liver injury and protected the mitochondria. Moreover, PEG 35 administration induced a significant phosphorylation of prosurvival protein kinase B (Akt) and activation of cytoprotective factors e-NOS and AMPK. In conclusion, intravenous PEG 35 efficiently protects steatotic livers exposed to cold IRI.
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Leishangthem BD, Sharma A, Bhatnagar A. Role of altered mitochondria functions in the pathogenesis of systemic lupus erythematosus. Lupus 2015; 25:272-81. [PMID: 26385216 DOI: 10.1177/0961203315605370] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 08/18/2015] [Indexed: 11/17/2022]
Abstract
Mitochondria, main producers of reactive-oxygen species (ROS), were studied to examine their role in the pathogenesis of systemic lupus erythematosus (SLE). PBMCs and mitochondria were isolated from SLE patients and healthy volunteers for various parameters. Mitochondrial ROS, swelling, hyperpolarization and levels of cytochrome c, caspase3 in the cells were assessed by flow cytometry. ROS was significantly increased in SLE patients (SLE vs controls: 1.83 ± 1.03 vs 1.10 ± 0.35; p < 0.0001). Depolarized state of mitochondria was greater in patients (SLE vs controls: 7.10 ± 5.50% vs 2.5 ± 1.8%; p < 0.05). Mitochondria swelling was found to be significantly altered in patients (SLE vs controls: 112.65 ± 36.56 vs 60.49 ± 20.69; p < 0.001). Expression of cytochrome c and caspase 3 (SLE vs controls: 1.37 ± 0.37% vs 1.01 ± 0.03%; 1.57 ± 0.46% vs 1.06 ± 0.07%; p < 0.05) respectively was found to be significantly increased in SLE. Further, the enzymatic activity of mitochondrial complex was assessed in isolated mitochondria. A significant decrease in activity of Complex I (SLE vs controls: 11.79 ± 3.18 vs 15.10 ± 6.38 nmol NADH oxidized/min/mg protein, p < 0.05); Complex IV (SLE vs control: 9.41 ± 5.16 vs 13.56 ± 5.92 nmol cytochrome c oxidized/min/mg protein, p < 0.05) and Complex V (SLE vs controls: 4.85 ± 1.39 vs 6.17 ± 2.02 nmol ATP hydrolyzed/min/mg protein, p < 0.05) was found in SLE patients in comparison to healthy controls. However, Complex II did not show significant variation in either group (SLE vs controls: 42.2 ± 28.6 vs 61.71 ± 42.3 nmol succinate oxidized/min/mg protein; ns). The decrease in enzyme activities of mitochondrial Complexes I, IV and V on one hand and ROS, hyperpolarization and apoptosis on the other points toward a possible role of mitochondria in the pathogenesis of lupus.
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Affiliation(s)
- B D Leishangthem
- Department of Biochemistry, Basic Medical Sciences Block, Panjab University, Chandigarh, India
| | - A Sharma
- Department of Internal Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - A Bhatnagar
- Department of Biochemistry, Basic Medical Sciences Block, Panjab University, Chandigarh, India
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