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Shinohe D, Kobayashi A, Gotoh M, Tanaka K, Ohta Y. Long-term inhibition of cyclophilin D results in intracellular translocation of calcein AM from mitochondria to lysosomes. Arch Biochem Biophys 2017; 613:53-60. [PMID: 27864141 DOI: 10.1016/j.abb.2016.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 11/13/2016] [Accepted: 11/14/2016] [Indexed: 11/17/2022]
Abstract
Cyclophilin D is a peptidyl-prolyl cis-trans isomerase localized in the mitochondrial matrix. Although its effects on mitochondrial characteristics have been well studied, its relation to the uptake of molecules by mitochondria remains unknown. Here, we demonstrated the effects of cyclophilin D on the intracellular translocation of calcein AM. Following addition of calcein AM to control cells or cells overexpressing wild-type cyclophilin D, calcein fluorescence was observed in mitochondria. However, long-term inhibition of cyclophilin D in these cells altered the localization of calcein fluorescence from mitochondria to lysosomes without changing mitochondrial esterase activity. In addition, depletion of glucose from the medium recovered calcein localization from lysosomes to mitochondria. This is the first demonstration of the effects of cyclophilin D on the intracellular translocation of molecules other than proteins and suggests that cyclophilin D may modify mitochondrial features by inducing the translocation of molecules to the mitochondria through the mechanism associated with cellular energy metabolism.
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Affiliation(s)
- Daisuke Shinohe
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Asuka Kobayashi
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Marina Gotoh
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Kotaro Tanaka
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Yoshihiro Ohta
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan.
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Shi X, Osaki H, Matsunomoto Y, Fujita C, Shinohe D, Ashida N, Choi H, Ohta Y. Partial contribution of mitochondrial permeability transition to t-butyl hydroperoxide-induced cell death. Biochem Biophys Rep 2016; 7:33-38. [PMID: 28955886 PMCID: PMC5613252 DOI: 10.1016/j.bbrep.2016.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 05/02/2016] [Accepted: 05/06/2016] [Indexed: 11/28/2022] Open
Abstract
Mitochondrial permeability transition (MPT) is thought to determine cell death under oxidative stress. However, MPT inhibitors only partially suppress oxidative stress-induced cell death. Here, we demonstrate that cells in which MPT is inhibited undergo cell death under oxidative stress. When C6 cells were exposed to 250 μM t-butyl hydroperoxide (t-BuOOH), the loss of a membrane potential-sensitive dye (tetramethylrhodamine ethyl ester, TMRE) from mitochondria was observed, indicating mitochondrial depolarization leading to cell death. The fluorescence of calcein entrapped in mitochondria prior to addition of t-BuOOH was significantly decreased to 70% after mitochondrial depolarization. Cyclosporin A suppressed the decrease in mitochondrial calcein fluorescence, but not mitochondrial depolarization. These results show that t-BuOOH induced cell death even when it did not induce MPT. Prior to MPT, lactate production and respiration were hampered. Taken together, these data indicate that the decreased turnover rate of glycolysis and mitochondrial respiration may be as vital as MPT for cell death induced under moderate oxidative stress. Cell death was induced in C6 cells by 250 μM t-BuOOH. Mitochondrial permeability transition (MPT) occurred before cell death. MPT was confirmed by observing calcein fluorescence in mitochondria. MPT inhibition did not prevent depolarization of mitochondria and cell death. Contribution of MPT to cell death is partial under moderate oxidative stress.
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Key Words
- AM, acetoxymethyl ester
- Cell death
- CsA, cyclosporin A
- DMEM, Dulbecco's modified Eagle's medium
- FBS, fetal bovine serum
- HBS, HEPES-buffered saline
- MPT, mitochondrial permeability transition
- Mitochondria
- Mitochondrial permeability transition pore
- Oxidative stress
- PPIase, peptidylprolyl cis-trans isomerase
- ROS, reactive oxygen species
- TMRE, tetramethylrhodamine ethyl ester
- t-BuOOH, t-butyl hydroperoxide
- t-butyl hydroperoxide
- ΔΨm, mitochondrial membrane potential
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Affiliation(s)
- Xiaolei Shi
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Hikaru Osaki
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Yoshihiro Matsunomoto
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Chisako Fujita
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Daisuke Shinohe
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Naoko Ashida
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Hyunjin Choi
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
| | - Yoshihiro Ohta
- Division of Biotechnology and Life Sciences, Institute of Engineering, Tokyo University of Agriculture and Technology, Nakacho 2-24-16, Koganei, Tokyo 184-8588, Japan
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Datler C, Pazarentzos E, Mahul-Mellier AL, Chaisaklert W, Hwang MS, Osborne F, Grimm S. CKMT1 regulates the mitochondrial permeability transition pore in a process that provides evidence for alternative forms of the complex. J Cell Sci 2014; 127:1816-28. [PMID: 24522192 DOI: 10.1242/jcs.140467] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The permeability transition pore (PT-pore) mediates cell death through the dissipation of the mitochondrial membrane potential (ΔΨm). Because the exact composition of the PT-pore is controversial, it is crucial to investigate the actual molecular constituents and regulators of this complex. We found that mitochondrial creatine kinase-1 (CKMT1) is a universal and functionally necessary gatekeeper of the PT-pore, as its depletion induces mitochondrial depolarization and apoptotic cell death. This can be inhibited efficiently by bongkrekic acid, a compound that is widely used to inhibit the PT-pore. However, when the 'classical' PT-pore subunits cyclophilin D and VDAC1 are pharmacologically inhibited or their expression levels reduced, mitochondrial depolarization by CKMT1 depletion remains unaffected. At later stages of drug-induced apoptosis, CKMT1 levels are reduced, suggesting that CKMT1 downregulation acts to reinforce the commitment of cells to apoptosis. A novel high-molecular-mass CKMT1 complex that is distinct from the known CKMT1 octamer disintegrates upon treatment with cytotoxic drugs, concomitant with mitochondrial depolarization. Our study provides evidence that CKMT1 is a key regulator of the PT-pore through a complex that is distinct from the classical PT-pore.
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Affiliation(s)
- Christoph Datler
- Division of Experimental Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
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Wiczer BM, Marcu R, Hawkins BJ. KB-R7943, a plasma membrane Na(+)/Ca(2+) exchanger inhibitor, blocks opening of the mitochondrial permeability transition pore. Biochem Biophys Res Commun 2014; 444:44-9. [PMID: 24434143 DOI: 10.1016/j.bbrc.2014.01.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 01/07/2014] [Indexed: 01/13/2023]
Abstract
The isothiourea derivative, KB-R7943, inhibits the reverse-mode of the plasma membrane sodium/calcium exchanger and protects against ischemia/reperfusion injury. The mechanism through which KB-R7943 confers protection, however, remains controversial. Recently, KB-R7943 has been shown to inhibit mitochondrial calcium uptake and matrix overload, which may contribute to its protective effects. While using KB-R7943 for this purpose, we find here no evidence that KB-R7943 directly blocks mitochondrial calcium uptake. Rather, we find that KB-R7943 inhibits opening of the mitochondrial permeability transition pore in permeabilized cells and isolated liver mitochondria. Furthermore, we find that this observation correlates with protection against calcium ionophore-induced mitochondrial membrane potential depolarization and cell death, without detrimental effects to basal mitochondrial membrane potential or complex I-dependent mitochondrial respiration. Our data reveal another mechanism through which KB-R7943 may protect against calcium-induced injury, as well as a novel means to inhibit the mitochondrial permeability transition pore.
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Affiliation(s)
- Brian M Wiczer
- Department of Anesthesiology and Pain Medicine, Mitochondria and Metabolism Center, University of Washington, Seattle, WA, United States
| | - Raluca Marcu
- Department of Anesthesiology and Pain Medicine, Mitochondria and Metabolism Center, University of Washington, Seattle, WA, United States
| | - Brian J Hawkins
- Department of Anesthesiology and Pain Medicine, Mitochondria and Metabolism Center, University of Washington, Seattle, WA, United States.
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Bhattacharjee S, Rietjens IMCM, Singh MP, Atkins TM, Purkait TK, Xu Z, Regli S, Shukaliak A, Clark RJ, Mitchell BS, Alink GM, Marcelis ATM, Fink MJ, Veinot JGC, Kauzlarich SM, Zuilhof H. Cytotoxicity of surface-functionalized silicon and germanium nanoparticles: the dominant role of surface charges. NANOSCALE 2013; 5:4870-83. [PMID: 23619571 PMCID: PMC3667208 DOI: 10.1039/c3nr34266b] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Although it is frequently hypothesized that surface (like surface charge) and physical characteristics (like particle size) play important roles in cellular interactions of nanoparticles (NPs), a systematic study probing this issue is missing. Hence, a comparative cytotoxicity study, quantifying nine different cellular endpoints, was performed with a broad series of monodisperse, well characterized silicon (Si) and germanium (Ge) NPs with various surface functionalizations. Human colonic adenocarcinoma Caco-2 and rat alveolar macrophage NR8383 cells were used to clarify the toxicity of this series of NPs. The surface coatings on the NPs appeared to dominate the cytotoxicity: the cationic NPs exhibited cytotoxicity, whereas the carboxylic acid-terminated and hydrophilic PEG- or dextran-terminated NPs did not. Within the cationic Si NPs, smaller Si NPs were more toxic than bigger ones. Manganese-doped (1% Mn) Si NPs did not show any added toxicity, which favors their further development for bioimaging. Iron-doped (1% Fe) Si NPs showed some added toxicity, which may be due to the leaching of Fe(3+) ions from the core. A silica coating seemed to impart toxicity, in line with the reported toxicity of silica. Intracellular mitochondria seem to be the target for the toxic NPs since a dose-, surface charge- and size-dependent imbalance of the mitochondrial membrane potential was observed. Such an imbalance led to a series of other cellular events for cationic NPs, like decreased mitochondrial membrane potential (ΔΨm) and ATP production, induction of ROS generation, increased cytoplasmic Ca(2+) content, production of TNF-α and enhanced caspase-3 activity. Taken together, the results explain the toxicity of Si NPs/Ge NPs largely by their surface characteristics, provide insight into the mode of action underlying the observed cytotoxicity, and give directions on synthesizing biocompatible Si and Ge NPs, as this is crucial for bioimaging and other applications in for example the field of medicine.
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Affiliation(s)
- Sourav Bhattacharjee
- Laboratory of Organic Chemistry, Wageningen University, Dreijenplein 8, 6703 HB Wageningen, The Netherlands
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