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Shew CY, Yoshikawa K. Crowding effect on the alignment of rod molecules confined in a spherical cavity. Chem Phys Lett 2023. [DOI: 10.1016/j.cplett.2023.140437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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Su X, Zhou H, Bao G, Wang J, Liu L, Zheng Q, Guo M, Zhang J. Nanomorphological and mechanical reconstruction of mesenchymal stem cells during early apoptosis detected by atomic force microscopy. Biol Open 2020; 9:bio048108. [PMID: 32086253 PMCID: PMC7132806 DOI: 10.1242/bio.048108] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 02/10/2020] [Indexed: 12/17/2022] Open
Abstract
Stem cell apoptosis exists widely in embryonic development, tissue regeneration, repair, aging and pathophysiology of disease. The molecular mechanism of stem cell apoptosis has been extensively investigated. However, alterations in biomechanics and nanomorphology have rarely been studied. Therefore, an apoptosis model was established for bone marrow mesenchymal stem cells (BMSCs) and the reconstruction of the mechanical properties and nanomorphology of the cells were investigated in detail. Atomic force microscopy (AFM), scanning electron microscopy (SEM), laser scanning confocal microscopy (LSCM), flow cytometry and Cell Counting Kit-8 analysis were applied to assess the cellular elasticity modulus, geometry, nanomorphology, cell surface ultrastructure, biological viability and early apoptotic signals (phosphatidylserine, PS). The results indicated that the cellular elastic modulus and volume significantly decreased, whereas the cell surface roughness obviously increased during the first 3 h of cytochalasin B (CB) treatment. Moreover, these alterations preceded the exposure of biological apoptotic signal PS. These findings suggested that cellular mechanical damage is connected with the apoptosis of BMSCs, and the alterations in mechanics and nanomorphology may be a sensitive index to detect alterations in cell viability during apoptosis. The results contribute to further understanding of apoptosis from the perspective of cell mechanics.
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Affiliation(s)
- Xuelian Su
- Key Laboratory of Stomatology of State Ethnic Affairs Commission, Northwest Minzu University, Lanzhou 730030, China
- Key Laboratory of Mechanics on Disaster and Environment in Western China, The Ministry of Education of China, Lanzhou University, Lanzhou 730000, China
- Key Laboratory of Oral Diseases of Gansu, Northwest Minzu University, Lanzhou 730030, China
| | - Haijing Zhou
- Key Laboratory of Stomatology of State Ethnic Affairs Commission, Northwest Minzu University, Lanzhou 730030, China
- Key Laboratory of Oral Diseases of Gansu, Northwest Minzu University, Lanzhou 730030, China
| | - Guangjie Bao
- Key Laboratory of Stomatology of State Ethnic Affairs Commission, Northwest Minzu University, Lanzhou 730030, China
- Key Laboratory of Oral Diseases of Gansu, Northwest Minzu University, Lanzhou 730030, China
| | - Jizeng Wang
- Key Laboratory of Mechanics on Disaster and Environment in Western China, The Ministry of Education of China, Lanzhou University, Lanzhou 730000, China
| | - Lin Liu
- Key Laboratory of Stomatology of State Ethnic Affairs Commission, Northwest Minzu University, Lanzhou 730030, China
- Key Laboratory of Oral Diseases of Gansu, Northwest Minzu University, Lanzhou 730030, China
| | - Qian Zheng
- Key Laboratory of Stomatology of State Ethnic Affairs Commission, Northwest Minzu University, Lanzhou 730030, China
- Key Laboratory of Oral Diseases of Gansu, Northwest Minzu University, Lanzhou 730030, China
| | - Manli Guo
- Key Laboratory of Stomatology of State Ethnic Affairs Commission, Northwest Minzu University, Lanzhou 730030, China
- Key Laboratory of Oral Diseases of Gansu, Northwest Minzu University, Lanzhou 730030, China
| | - Jinting Zhang
- Key Laboratory of Stomatology of State Ethnic Affairs Commission, Northwest Minzu University, Lanzhou 730030, China
- Key Laboratory of Oral Diseases of Gansu, Northwest Minzu University, Lanzhou 730030, China
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Su X, Zhang L, Kang H, Zhang B, Bao G, Wang J. Mechanical, nanomorphological and biological reconstruction of early‑stage apoptosis in HeLa cells induced by cytochalasin B. Oncol Rep 2018; 41:928-938. [PMID: 30535459 PMCID: PMC6313055 DOI: 10.3892/or.2018.6921] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/22/2018] [Indexed: 12/29/2022] Open
Abstract
There is a growing interest in the fact that mechanical signals may be as important as biological signals in evaluating cell viability. To investigate the alterations in biomechanics, nanomorphology and biological apoptotic signals during early apoptosis, an apoptosis model was established for cervical cancer HeLa cells induced by cytochalasin B (CB). The cellular mechanical properties, geometry, morphology and expression of key apoptotic proteins were systematically analyzed. The findings indicated a marked decline in cellular elastic modulus and volume and a considerable increase in surface roughness occurring prior to the activation of biological apoptosis signals (such as phosphatidylserine exposure or activation of CD95/Fas). Moreover, the depolymerization of filamentous actin aggravated the intracellular crowding degree, which induced the redistribution of different-sized protein molecules and protrusions across the cell membrane arising from excluded volume interactions. Statistical analysis revealed that the disassembly of the actin cytoskeleton was negatively correlated with the cellular elastic modulus and volume, but was positively correlated with surface roughness and CD95/Fas activation. The results of the present study suggest that compared with biological signals, mechanical and geometrical reconstruction is more sensitive during apoptosis and the increase in cell surface roughness arises from the redistribution of biophysical molecules. These results contribute to our in-depth understanding of the apoptosis mechanisms of cancer cells mediated by cytochalasin B.
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Affiliation(s)
- Xuelian Su
- College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Ling Zhang
- Key Laboratory of Mechanics on Disaster and Environment in Western China, The Ministry of Education of China, Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Hong Kang
- Key Laboratory of Mechanics on Disaster and Environment in Western China, The Ministry of Education of China, Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Baoping Zhang
- Key Laboratory of Mechanics on Disaster and Environment in Western China, The Ministry of Education of China, Lanzhou University, Lanzhou, Gansu 730000, P.R. China
| | - Guangjie Bao
- Key Laboratory of Stomatology of The State Ethnic Affairs Commission, Northwest Minzu University, Lanzhou, Gansu 730030, P.R. China
| | - Jizeng Wang
- College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000, P.R. China
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Shew CY, Oda S, Yoshikawa K. Localization switching of a large object in a crowded cavity: A rigid/soft object prefers surface/inner positioning. J Chem Phys 2018; 147:204901. [PMID: 29195278 DOI: 10.1063/1.5000762] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
For living cells in the real world, a large organelle is commonly positioned in the inner region away from membranes, such as the nucleus of eukaryotic cells, the nucleolus of nuclei, mitochondria, chloroplast, Golgi body, etc. It contradicts the expectation by the current depletion-force theory in that the larger particle should be excluded from the inner cell space onto cell boundaries in a crowding media. Here we simply model a sizable organelle as a soft-boundary large particle allowing crowders, which are smaller hard spheres in the model, to intrude across its boundary. The results of Monte Carlo simulation indicate that the preferential location of the larger particle switches from the periphery into the inner region of the cavity by increasing its softness. An integral equation theory is further developed to account for the structural features of the model, and the theoretical predictions are found consistent with our simulation results.
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Affiliation(s)
- Chwen-Yang Shew
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, New York 10016, USA and Department of Chemistry, College of Staten Island, Staten Island, New York 10314, USA
| | - Soutaro Oda
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe 610-0394, Japan
| | - Kenichi Yoshikawa
- Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe 610-0394, Japan
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Hamada T, Fujimoto R, Shimobayashi SF, Ichikawa M, Takagi M. Molecular behavior of DNA in a cell-sized compartment coated by lipids. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:062717. [PMID: 26172746 DOI: 10.1103/physreve.91.062717] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Indexed: 06/04/2023]
Abstract
The behavior of long DNA molecules in a cell-sized confined space was investigated. We prepared water-in-oil droplets covered by phospholipids, which mimic the inner space of a cell, following the encapsulation of DNA molecules with unfolded coil and folded globule conformations. Microscopic observation revealed that the adsorption of coiled DNA onto the membrane surface depended on the size of the vesicular space. Globular DNA showed a cell-size-dependent unfolding transition after adsorption on the membrane. Furthermore, when DNA interacted with a two-phase membrane surface, DNA selectively adsorbed on the membrane phase, such as an ordered or disordered phase, depending on its conformation. We discuss the mechanism of these trends by considering the free energy of DNA together with a polyamine in the solution. The free energy of our model was consistent with the present experimental data. The cooperative interaction of DNA and polyamines with a membrane surface leads to the size-dependent behavior of molecular systems in a small space. These findings may contribute to a better understanding of the physical mechanism of molecular events and reactions inside a cell.
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Affiliation(s)
- Tsutomu Hamada
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - Rie Fujimoto
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | | | - Masatoshi Ichikawa
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Masahiro Takagi
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
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Shew CY, Yoshikawa K. A toy model for nucleus-sized crowding confinement. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:064118. [PMID: 25563689 DOI: 10.1088/0953-8984/27/6/064118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We conduct Monte Carlo simulations to understand the spatial distribution of a polymer molecule confined within a rigid spherical capsule under crowding conditions, via a bead-spring chain model. To adjust the crowding level, the polymer is mixed with spherical crowders. As the interior of the capsule becomes more crowded, chain monomers tend to move to the capsule boundary under the penalty of conformational entropy. By incorporating some attraction between monomers and crowders, the polymer chain moves away from the capsule boundary. The interplay, between the conformational entropy, DNA-protein interaction, and molecular crowding induced depletion force between the chain and capsule boundary, may be essential to elucidate the heterogeneous chromatin structure in nuclei. Furthermore, the effects of chain length and size disparity between the monomers and the crowders are also investigated preliminarily.
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Affiliation(s)
- Chwen-Yang Shew
- Department of Chemistry, City University of New York, College of Staten Island, 2800 Victory Boulevard, Staten Island, NY 10314, USA
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