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Lin WJ, Shi WP, Ge WY, Chen LL, Guo WH, Shang P, Yin DC. Magnetic Fields Reduce Apoptosis by Suppressing Phase Separation of Tau-441. RESEARCH (WASHINGTON, D.C.) 2023; 6:0146. [PMID: 37228640 PMCID: PMC10204748 DOI: 10.34133/research.0146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 04/21/2023] [Indexed: 05/27/2023]
Abstract
The biological effects of magnetic fields (MFs) have been a controversial issue. Fortunately, in recent years, there has been increasing evidence that MFs do affect biological systems. However, the physical mechanism remains unclear. Here, we show that MFs (16 T) reduce apoptosis in cell lines by inhibiting liquid-liquid phase separation (LLPS) of Tau-441, suggesting that the MF effect on LLPS may be one of the mechanisms for understanding the "mysterious" magnetobiological effects. The LLPS of Tau-441 occurred in the cytoplasm after induction with arsenite. The phase-separated droplets of Tau-441 recruited hexokinase (HK), resulting in a decrease in the amount of free HK in the cytoplasm. In cells, HK and Bax compete to bind to the voltage-dependent anion channel (VDAC I) on the mitochondrial membrane. A decrease in the number of free HK molecules increased the chance of Bax binding to VDAC I, leading to increased Bax-mediated apoptosis. In the presence of a static MF, LLPS was marked inhibited and HK recruitment was reduced, resulting in an increased probability of HK binding to VDAC I and a decreased probability of Bax binding to VDAC I, thus reducing Bax-mediated apoptosis. Our findings revealed a new physical mechanism for understanding magnetobiological effects from the perspective of LLPS. In addition, these results show the potential applications of physical environments, such as MFs in this study, in the treatment of LLPS-related diseases.
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Affiliation(s)
| | | | - Wan-Yi Ge
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences,
Northwestern Polytechnical University, 127 Youyixi Road, Xi'an 710072, Shaanxi, PR China
| | - Liang-Liang Chen
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences,
Northwestern Polytechnical University, 127 Youyixi Road, Xi'an 710072, Shaanxi, PR China
| | - Wei-Hong Guo
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences,
Northwestern Polytechnical University, 127 Youyixi Road, Xi'an 710072, Shaanxi, PR China
| | - Peng Shang
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences,
Northwestern Polytechnical University, 127 Youyixi Road, Xi'an 710072, Shaanxi, PR China
| | - Da-Chuan Yin
- Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences,
Northwestern Polytechnical University, 127 Youyixi Road, Xi'an 710072, Shaanxi, PR China
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Walker JC, Jorgensen AM, Sarkar A, Gent SP, Messerli MA. Anionic polymers amplify electrokinetic perfusion through extracellular matrices. Front Bioeng Biotechnol 2022; 10:983317. [PMID: 36225599 PMCID: PMC9548625 DOI: 10.3389/fbioe.2022.983317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/07/2022] [Indexed: 11/17/2022] Open
Abstract
Electrical stimulation (ES) promotes healing of chronic epidermal wounds and delays degeneration of articular cartilage. Despite electrotherapeutic treatment of these non-excitable tissues, the mechanisms by which ES promotes repair are unknown. We hypothesize that a beneficial role of ES is dependent on electrokinetic perfusion in the extracellular space and that it mimics the effects of interstitial flow. In vivo, the extracellular space contains mixtures of extracellular proteins and negatively charged glycosaminoglycans and proteoglycans surrounding cells. While these anionic macromolecules promote water retention and increase mechanical support under compression, in the presence of ES they should also enhance electro-osmotic flow (EOF) to a greater extent than proteins alone. To test this hypothesis, we compare EOF rates between artificial matrices of gelatin (denatured collagen) with matrices of gelatin mixed with anionic polymers to mimic endogenous charged macromolecules. We report that addition of anionic polymers amplifies EOF and that a matrix comprised of 0.5% polyacrylate and 1.5% gelatin generates EOF with similar rates to those reported in cartilage. The enhanced EOF reduces mortality of cells at lower applied voltage compared to gelatin matrices alone. We also use modeling to describe the range of thermal changes that occur during these electrokinetic experiments and during electrokinetic perfusion of soft tissues. We conclude that the negative charge density of native extracellular matrices promotes electrokinetic perfusion during electrical therapies in soft tissues and may promote survival of artificial tissues and organs prior to vascularization and during transplantation.
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Affiliation(s)
- Joseph C. Walker
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States
| | - Ashley M. Jorgensen
- Department of Mechanical Engineering, South Dakota State University, Brookings, SD, United States
| | - Anyesha Sarkar
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States
| | - Stephen P. Gent
- Department of Mechanical Engineering, South Dakota State University, Brookings, SD, United States
| | - Mark A. Messerli
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States
- *Correspondence: Mark A. Messerli,
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