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Kitamura A, Oasa S, Kawaguchi H, Osaka M, Vukojević V, Kinjo M. Increased intracellular crowding during hyperosmotic stress. Sci Rep 2023; 13:11834. [PMID: 37481632 PMCID: PMC10363123 DOI: 10.1038/s41598-023-39090-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 07/20/2023] [Indexed: 07/24/2023] Open
Abstract
Hyperosmotic stress activates in live cells numerous processes and also promotes intracellular protein/RNA aggregation and phase separation. However, the time course and the extent of these changes remain largely uncharacterized. To investigate dynamic changes in intracellular macromolecular crowding (MMC) induced by hyperosmotic stress in live cells, we used fluorescence lifetime imaging microscopy and fluorescence correlation spectroscopy (FCS) to quantify changes in the local environment by measuring the fluorescence lifetime and the diffusion of the monomeric enhanced green fluorescent protein (eGFP), respectively. Real-time monitoring of eGFP fluorescence lifetime showed that a faster response to environmental changes due to MMC is observed than when measuring the acceptor/donor emission ratio using the MMC-sensitive Förster resonance energy transfer sensor (GimRET). This suggests that eGFP molecular electronic states and/or collision frequency are affected by changes in the immediate surroundings due to MMC without requiring conformational changes as is the case for the GimRET sensor. Furthermore, eGFP diffusion assessed by FCS indicated higher intracellular viscosity due to increased MMC during hyperosmotic stress. Our findings reveal that changes in eGFP fluorescence lifetime and diffusion are early indicators of elevated intracellular MMC. Our approach can therefore be used to reveal in live cells short-lived transient states through which MMC builds over time, which could not be observed when measuring changes in other physical properties that occur at slower time scales.
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Affiliation(s)
- Akira Kitamura
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan.
| | - Sho Oasa
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM), Karolinska Institutet, 17176, Stockholm, Sweden
| | - Haruka Kawaguchi
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Misato Osaka
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Vladana Vukojević
- Department of Clinical Neuroscience (CNS), Center for Molecular Medicine (CMM), Karolinska Institutet, 17176, Stockholm, Sweden
| | - Masataka Kinjo
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
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2
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Inui M, Hamada Y, Sejima N, Ueda N, Katayama T, Ono K, Nagahama K. Exportin-inspired artificial cell nuclear-exporting nanosystems. NANOSCALE ADVANCES 2022; 4:2637-2641. [PMID: 36132290 PMCID: PMC9419527 DOI: 10.1039/d2na00050d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
Inspired by the structural and chemical features of naturally occurring importin/exportin that allows them to pass through the nuclear pore complexes, we successfully developed an artificial nuclear-exporting nanosystem capable of eliminating compounds accumulated abnormally in the nucleus.
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Affiliation(s)
- Mitsuo Inui
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University 7-1-20 Minatojima-minamimachi, Chuo-ku Kobe 650-0047 Japan
| | - Yuta Hamada
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University 7-1-20 Minatojima-minamimachi, Chuo-ku Kobe 650-0047 Japan
| | - Nana Sejima
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University 7-1-20 Minatojima-minamimachi, Chuo-ku Kobe 650-0047 Japan
| | - Natsumi Ueda
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University 7-1-20 Minatojima-minamimachi, Chuo-ku Kobe 650-0047 Japan
| | - Tokitaka Katayama
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University 7-1-20 Minatojima-minamimachi, Chuo-ku Kobe 650-0047 Japan
| | - Kimika Ono
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University 7-1-20 Minatojima-minamimachi, Chuo-ku Kobe 650-0047 Japan
| | - Koji Nagahama
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University 7-1-20 Minatojima-minamimachi, Chuo-ku Kobe 650-0047 Japan
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3
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Payne-Dwyer AL, Leake MC. Single-Molecular Quantification of Flowering Control Proteins Within Nuclear Condensates in Live Whole Arabidopsis Root. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2476:311-328. [PMID: 35635712 DOI: 10.1007/978-1-0716-2221-6_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Here we describe the coupled standardization of two complementary fluorescence imaging techniques and apply it to liquid-liquid phase-separated condensates formed from an EGFP fluorescent reporter of flowering control locus A (FCA), a protein that associates with chromosomal DNA in plants during epigenetic regulation of the flowering process. First, we use home-built single-molecule Slimfield microscopy to establish a fluorescent protein standard. This sample comprises live yeast cells expressing Mig1 protein, a metabolic regulator which localizes to the nucleus under conditions of high glucose, fused to the same type of EGFP label as for the FCA fusion construct. Then we employ commercial confocal AiryScan microscopy to study the same standard. Finally, we demonstrate how to quantify FCA-EGFP nuclear condensates in intact root tips at rapid timescales and apply this calibration. This method is a valuable approach to obtaining single-molecule precise stoichiometry and copy number estimates of protein condensates that are integrated into the chromosome architecture of plants, using confocal instrumentation that lacks de facto single-molecule detection sensitivity.
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Affiliation(s)
- Alex L Payne-Dwyer
- Department of Physics, University of York, York, UK.
- Departments of Physics and Biology, University of York, York, UK.
| | - Mark C Leake
- Departments of Physics and Biology, University of York, York, UK
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Lv R, Raab M, Wang Y, Tian J, Lin J, Prasad PN. Nanochemistry advancing photon conversion in rare-earth nanostructures for theranostics. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214486] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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5
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Effect of Temperature on Re-entrant Condensation of Globular Protein in Presence of Tri-valent Ions. J Fluoresc 2022; 32:791-797. [DOI: 10.1007/s10895-021-02874-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/17/2021] [Indexed: 11/26/2022]
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6
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Levchenko SM, Pliss A, Peng X, Prasad PN, Qu J. Fluorescence lifetime imaging for studying DNA compaction and gene activities. LIGHT, SCIENCE & APPLICATIONS 2021; 10:224. [PMID: 34728612 PMCID: PMC8563720 DOI: 10.1038/s41377-021-00664-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 10/04/2021] [Accepted: 10/18/2021] [Indexed: 05/04/2023]
Abstract
Optical imaging is a most useful and widespread technique for the investigation of the structure and function of the cellular genomes. However, an analysis of immensely convoluted and irregularly compacted DNA polymer is highly challenging even by modern super-resolution microscopy approaches. Here we propose fluorescence lifetime imaging (FLIM) for the advancement of studies of genomic structure including DNA compaction, replication as well as monitoring of gene expression. The proposed FLIM assay employs two independent mechanisms for DNA compaction sensing. One mechanism relies on the inverse quadratic relation between the fluorescence lifetimes of fluorescence probes incorporated into DNA and their local refractive index, variable due to DNA compaction density. Another mechanism is based on the Förster resonance energy transfer (FRET) process between the donor and the acceptor fluorophores, both incorporated into DNA. Both these proposed mechanisms were validated in cultured cells. The obtained data unravel a significant difference in compaction of the gene-rich and gene-poor pools of genomic DNA. We show that the gene-rich DNA is loosely compacted compared to the dense DNA domains devoid of active genes.
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Affiliation(s)
- Svitlana M Levchenko
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, 518060, China
- Department of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Krakow, Poland
| | - Artem Pliss
- Institute for Lasers, Photonics and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY, 14260-3000, USA
| | - Xiao Peng
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, 518060, China
| | - Paras N Prasad
- Institute for Lasers, Photonics and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY, 14260-3000, USA.
| | - Junle Qu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, 518060, China.
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7
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Wessén J, Pal T, Das S, Lin YH, Chan HS. A Simple Explicit-Solvent Model of Polyampholyte Phase Behaviors and Its Ramifications for Dielectric Effects in Biomolecular Condensates. J Phys Chem B 2021; 125:4337-4358. [PMID: 33890467 DOI: 10.1021/acs.jpcb.1c00954] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Biomolecular condensates such as membraneless organelles, underpinned by liquid-liquid phase separation (LLPS), are important for physiological function, with electrostatics, among other interaction types, being a prominent force in their assembly. Charge interactions of intrinsically disordered proteins (IDPs) and other biomolecules are sensitive to the aqueous dielectric environment. Because the relative permittivity of protein is significantly lower than that of water, the interior of an IDP condensate is expected to be a relatively low-dielectric regime, which aside from its possible functional effects on client molecules should facilitate stronger electrostatic interactions among the scaffold IDPs. To gain insight into this LLPS-induced dielectric heterogeneity, addressing in particular whether a low-dielectric condensed phase entails more favorable LLPS than that posited by assuming IDP electrostatic interactions are uniformly modulated by the higher dielectric constant of the pure solvent, we consider a simplified multiple-chain model of polyampholytes immersed in explicit solvents that are either polarizable or possess a permanent dipole. Notably, simulated phase behaviors of these systems exhibit only minor to moderate differences from those obtained using implicit-solvent models with a uniform relative permittivity equals to that of pure solvent. Buttressed by theoretical treatments developed here using random phase approximation and polymer field-theoretic simulations, these observations indicate a partial compensation of effects between favorable solvent-mediated interactions among the polyampholytes in the condensed phase and favorable polyampholyte-solvent interactions in the dilute phase, often netting only a minor enhancement of overall LLPS propensity from the very dielectric heterogeneity that arises from the LLPS itself. Further ramifications of this principle are discussed.
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Affiliation(s)
- Jonas Wessén
- Department of Biochemistry, University of Toronto, Medical Sciences Building-5th Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Tanmoy Pal
- Department of Biochemistry, University of Toronto, Medical Sciences Building-5th Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Suman Das
- Department of Biochemistry, University of Toronto, Medical Sciences Building-5th Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Yi-Hsuan Lin
- Department of Biochemistry, University of Toronto, Medical Sciences Building-5th Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.,Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Hue Sun Chan
- Department of Biochemistry, University of Toronto, Medical Sciences Building-5th Floor, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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8
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Liang CQ, Wang L, Luo YY, Li QQ, Li YM. Capturing protein droplets: label-free visualization and detection of protein liquid-liquid phase separation with an aggregation-induced emission fluorogen. Chem Commun (Camb) 2021; 57:3805-3808. [PMID: 33876127 DOI: 10.1039/d1cc00947h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We developed a new method for protein droplet visualization by means of a droplet probe (DroProbe) based on an aggregation-induced emission (AIE) fluorogen. A simple method for viscosity comparison of the protein condensed phase based on the lifetime of the DroProbe was also developed.
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Affiliation(s)
- Chu-Qiao Liang
- Key Lab of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University Beijing, 100084, P. R. China.
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9
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Luminescent probes for luminescence lifetime sensing and imaging in live cells: a narrative review. JOURNAL OF BIO-X RESEARCH 2020. [DOI: 10.1097/jbr.0000000000000081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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10
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Simpson LW, Good TA, Leach JB. Protein folding and assembly in confined environments: Implications for protein aggregation in hydrogels and tissues. Biotechnol Adv 2020; 42:107573. [PMID: 32512220 DOI: 10.1016/j.biotechadv.2020.107573] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 05/03/2020] [Accepted: 05/30/2020] [Indexed: 12/20/2022]
Abstract
In the biological milieu of a cell, soluble crowding molecules and rigid confined environments strongly influence whether the protein is properly folded, intrinsically disordered proteins assemble into distinct phases, or a denatured or aggregated protein species is favored. Such crowding and confinement factors act to exclude solvent volume from the protein molecules, resulting in an increased local protein concentration and decreased protein entropy. A protein's structure is inherently tied to its function. Examples of processes where crowding and confinement may strongly influence protein function include transmembrane protein dimerization, enzymatic activity, assembly of supramolecular structures (e.g., microtubules), nuclear condensates containing transcriptional machinery, protein aggregation in the contexts of disease and protein therapeutics. Historically, most protein structures have been determined from pure, dilute protein solutions or pure crystals. However, these are not the environments in which these proteins function. Thus, there has been an increased emphasis on analyzing protein structure and dynamics in more "in vivo-like" environments. Complex in vitro models using hydrogel scaffolds to study proteins may better mimic features of the in vivo environment. Therefore, analytical techniques need to be optimized for real-time analysis of proteins within hydrogel scaffolds.
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Affiliation(s)
- Laura W Simpson
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Eng 314, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Theresa A Good
- Division of Molecular and Cellular Biosciences, National Science Foundation, 2415 Eisenhower Ave, Alexandria, VA 22314, USA
| | - Jennie B Leach
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Eng 314, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
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11
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Peng Z, Nie K, Song Y, Liu H, Zhou Y, Yuan Y, Chen D, Peng X, Yan W, Song J, Qu J. Monitoring the Cellular Delivery of Doxorubicin-Cu Complexes in Cells by Fluorescence Lifetime Imaging Microscopy. J Phys Chem A 2020; 124:4235-4240. [PMID: 32364735 DOI: 10.1021/acs.jpca.0c00182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In the prodrug research field, information obtained from traditional end point biochemical assays in drug effect studies could provide neither the dynamic processes nor heterogeneous responses of individual cells. In situ imaging microscopy techniques, especially fluorescence lifetime imaging microscopy (FLIM), could fulfill these requirements. In this work, we used FLIM techniques to observe the entry and release of doxorubicin (Dox)-Cu complexes in live KYSE150 cells. The Dox-Cu complex has weaker fluorescence signals but similar lifetime values as compared to the raw Dox, whose fluorescence could be released by the addition of biothiol compound (such as glutathione). The cell viability results indicated that the Dox-Cu compound has a satisfactory killing effect on KYSE150 cells. The FLIM data showed that free doxorubicin was released from Dox-Cu complexes in cytoplasm of KYSE150 cells and then accumulated in the nucleus. After 90 min administration, the fluorescence lifetime signals reached 1.21 and 1.46 ns in the cytoplasm and nucleus, respectively, reflecting the transformation and transportation of Dox-Cu complexes. In conclusion, this work provides a satisfactory example for the research of prodrug monitored by FLIM techniques, expanding the useful applications of FLIM technique in drug development.
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Affiliation(s)
- Zheng Peng
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Kaixuan Nie
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Yiwan Song
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Hao Liu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Yingxin Zhou
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Yufeng Yuan
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Danni Chen
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Xiao Peng
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Wei Yan
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Jun Song
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
| | - Junle Qu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, P. R. China
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12
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Yang F, Wang Y, Jiang X, Lin B, Lv R. Optimized Multimetal Sensitized Phosphor for Enhanced Red Up-Conversion Luminescence by Machine Learning. ACS COMBINATORIAL SCIENCE 2020; 22:285-296. [PMID: 32286788 DOI: 10.1021/acscombsci.0c00035] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In this research, machine learning including the genetic algorithm (GA) and support vector machine (SVM) algorithm is used to solve the "low up-conversion luminescence (UCL) intensity" problem in order to find the optimal phosphor with enhanced red UCL emission using multielement K/Li/Mn metal modulation. Compared with the first generation of phosphors, the best phosphors' fluorescence intensity occurs in the third generation optimized by the GA, with a stronger brightness (4.91-fold), a higher relative quantum yield (6.40-fold), and an enhanced tissue penetration depth (by 5 mm). The single and multiple dopants effect on the upconversion intensity of K+Li+Mn sensitizers is also studied: the intensity increases first and then decreases with the increase of Yb/Er/K+Li+Mn content, and the optimized K+Li+Mn concentration is 6.03%. In order to confirm the stability of the brightness optimization by the GA, a batch of phosphors was synthesized with the same element proportion, and the similarity of fluorescence intensity of two batches of phosphors was evaluated by the SVM algorithm with the classification accuracy index. Finally, the optimized phosphor was used for bioimaging and phosphor-LED.
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Affiliation(s)
- Fan Yang
- Engineering Research Center of Molecular and Neuro Imaging, Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi 710071, China
| | - Yanxing Wang
- Engineering Research Center of Molecular and Neuro Imaging, Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi 710071, China
| | - Xue Jiang
- Engineering Research Center of Molecular and Neuro Imaging, Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi 710071, China
| | - Bi Lin
- Engineering Research Center of Molecular and Neuro Imaging, Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi 710071, China
| | - Ruichan Lv
- Engineering Research Center of Molecular and Neuro Imaging, Ministry of Education, School of Life Science and Technology, Xidian University, Xi’an, Shaanxi 710071, China
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Abstract
Many biomolecular condensates appear to form via spontaneous or driven processes that have the hallmarks of intracellular phase transitions. This suggests that a common underlying physical framework might govern the formation of functionally and compositionally unrelated biomolecular condensates. In this review, we summarize recent work that leverages a stickers-and-spacers framework adapted from the field of associative polymers for understanding how multivalent protein and RNA molecules drive phase transitions that give rise to biomolecular condensates. We discuss how the valence of stickers impacts the driving forces for condensate formation and elaborate on how stickers can be distinguished from spacers in different contexts. We touch on the impact of sticker- and spacer-mediated interactions on the rheological properties of condensates and show how the model can be mapped to known drivers of different types of biomolecular condensates.
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Affiliation(s)
- Jeong-Mo Choi
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, 63130, USA; , ,
- Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri, 63130, USA
- Natural Science Research Institute, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Alex S Holehouse
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, 63130, USA; , ,
- Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri, 63130, USA
| | - Rohit V Pappu
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, 63130, USA; , ,
- Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri, 63130, USA
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14
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Pliss A, Prasad PN. High resolution mapping of subcellular refractive index by Fluorescence Lifetime Imaging: a next frontier in quantitative cell science? Methods Appl Fluoresc 2020; 8:032001. [PMID: 32235079 DOI: 10.1088/2050-6120/ab8571] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Intracellular refractive index (RI) is an essential biophysical parameter, which best represents the mass and the distribution of proteins in the cell interior, including high-density accumulations in membraneless organelles. For RI measurements, a number of sophisticated techniques have been developed; however most of the new approaches are either insufficiently sensitive to intracellular variations of proteins distribution or are not compatible with live cell studies. Here, we outline the fluorescence lifetime imaging (FLIM) strategy for high resolution mapping of subcellular RI. We provide an example of our recent studies in which we utilize FLIM for measurements and monitoring of local RI in the major membraneless organelles within live cultured cells.
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15
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Lin F, Das P, Zhao Y, Shen B, Hu R, Zhou F, Liu L, Qu J. Monitoring the endocytosis of bovine serum albumin based on the fluorescence lifetime of small squaraine dye in living cells. BIOMEDICAL OPTICS EXPRESS 2020; 11:149-159. [PMID: 32010506 PMCID: PMC6968756 DOI: 10.1364/boe.11.000149] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/20/2019] [Accepted: 11/26/2019] [Indexed: 05/22/2023]
Abstract
Bovine serum albumin (BSA) has a wide range of physiological functions involving the binding, transportation, and delivery of fatty acids, porphyrins, bilirubin, steroids, etc. In the present study, we prepared a small squaraine dye (SD), which can selectively detect BSA using fluorescence lifetime imaging microscopy (FLIM), to monitor the endocytosis of BSA in live cultured cells in real time. This approach revealed that BSA uptake is concentration-dependent in living cells. Furthermore, we used paclitaxel (PTX), a chemotherapeutic drug, to influence the endocytosis of BSA in living cells. The results demonstrated that the endocytic rate was clearly reduced after pretreatment with 0.4 µM PTX for 2 h. The present study demonstrates the potential value of using the fluorescence lifetime of SD to detect BSA concentration and study the physiological mechanism of chemotherapeutic drugs.
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Affiliation(s)
- Fangrui Lin
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province & Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong Province 518060, China
| | - Pintu Das
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province & Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong Province 518060, China
| | - Yihua Zhao
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province & Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong Province 518060, China
| | - Binglin Shen
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province & Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong Province 518060, China
| | - Rui Hu
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province & Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong Province 518060, China
| | - Feifan Zhou
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province & Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong Province 518060, China
| | - Liwei Liu
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province & Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong Province 518060, China
| | - Junle Qu
- Key Laboratory of Optoelectronic Devices and Systems of Guangdong Province & Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong Province 518060, China
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16
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Bracha D, Walls MT, Brangwynne CP. Probing and engineering liquid-phase organelles. Nat Biotechnol 2019; 37:1435-1445. [DOI: 10.1038/s41587-019-0341-6] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 10/28/2019] [Indexed: 01/02/2023]
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Spannl S, Tereshchenko M, Mastromarco GJ, Ihn SJ, Lee HO. Biomolecular condensates in neurodegeneration and cancer. Traffic 2019; 20:890-911. [PMID: 31606941 DOI: 10.1111/tra.12704] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 10/03/2019] [Accepted: 10/06/2019] [Indexed: 12/14/2022]
Abstract
The intracellular environment is partitioned into functionally distinct compartments containing specific sets of molecules and reactions. Biomolecular condensates, also referred to as membrane-less organelles, are diverse and abundant cellular compartments that lack membranous enclosures. Molecules assemble into condensates by phase separation; multivalent weak interactions drive molecules to separate from their surroundings and concentrate in discrete locations. Biomolecular condensates exist in all eukaryotes and in some prokaryotes, and participate in various essential house-keeping, stress-response and cell type-specific processes. An increasing number of recent studies link abnormal condensate formation, composition and material properties to a number of disease states. In this review, we discuss current knowledge and models describing the regulation of condensates and how they become dysregulated in neurodegeneration and cancer. Further research on the regulation of biomolecular phase separation will help us to better understand their role in cell physiology and disease.
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Affiliation(s)
- Stephanie Spannl
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Maria Tereshchenko
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | | | - Sean J Ihn
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Hyun O Lee
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Canada Research Chairs Program, University of Toronto, Toronto, Ontario, Canada
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Lv R, Jiang X, Yang F, Wang Y, Feng M, Liu J, Tian J. Degradable magnetic-response photoacoustic/up-conversion luminescence imaging-guided photodynamic/photothermal antitumor therapy. Biomater Sci 2019; 7:4558-4567. [DOI: 10.1039/c9bm00853e] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In this research, a degradable uniform mesoporous platform was designed as an imaging-guided photothermal therapy (PTT)/photodynamic therapy (PDT) agent.
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Affiliation(s)
- Ruichan Lv
- Engineering Research Center of Molecular and Neuro Imaging
- Ministry of Education
- School of Life Science and Technology
- Xidian University
- Xi'an
| | - Xue Jiang
- Engineering Research Center of Molecular and Neuro Imaging
- Ministry of Education
- School of Life Science and Technology
- Xidian University
- Xi'an
| | - Fan Yang
- Engineering Research Center of Molecular and Neuro Imaging
- Ministry of Education
- School of Life Science and Technology
- Xidian University
- Xi'an
| | - Yanxing Wang
- Engineering Research Center of Molecular and Neuro Imaging
- Ministry of Education
- School of Life Science and Technology
- Xidian University
- Xi'an
| | - Miao Feng
- Engineering Research Center of Molecular and Neuro Imaging
- Ministry of Education
- School of Life Science and Technology
- Xidian University
- Xi'an
| | - Jun Liu
- Engineering Research Center of Molecular and Neuro Imaging
- Ministry of Education
- School of Life Science and Technology
- Xidian University
- Xi'an
| | - Jie Tian
- Engineering Research Center of Molecular and Neuro Imaging
- Ministry of Education
- School of Life Science and Technology
- Xidian University
- Xi'an
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