1
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Miettinen TP, Gomez AL, Wu Y, Wu W, Usherwood TR, Hwang Y, Roller BRK, Polz MF, Manalis SR. Cell size, density, and nutrient dependency of unicellular algal gravitational sinking velocities. SCIENCE ADVANCES 2024; 10:eadn8356. [PMID: 38968348 PMCID: PMC11225777 DOI: 10.1126/sciadv.adn8356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 06/04/2024] [Indexed: 07/07/2024]
Abstract
Eukaryotic phytoplankton, also known as algae, form the basis of marine food webs and drive marine carbon sequestration. Algae must regulate their motility and gravitational sinking to balance access to light at the surface and nutrients in deeper layers. However, the regulation of gravitational sinking remains largely unknown, especially in motile species. Here, we quantify gravitational sinking velocities according to Stokes' law in diverse clades of unicellular marine microalgae to reveal the cell size, density, and nutrient dependency of sinking velocities. We identify a motile algal species, Tetraselmis sp., that sinks faster when starved due to a photosynthesis-driven accumulation of carbohydrates and a loss of intracellular water, both of which increase cell density. Moreover, the regulation of cell sinking velocities is connected to proliferation and can respond to multiple nutrients. Overall, our work elucidates how cell size and density respond to environmental conditions to drive the vertical migration of motile algae.
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Affiliation(s)
- Teemu P. Miettinen
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Annika L. Gomez
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yanqi Wu
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Weida Wu
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Thomas R. Usherwood
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Harvard-MIT Department of Health Sciences and Technology, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yejin Hwang
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Benjamin R. K. Roller
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, 1030, Austria
| | - Martin F. Polz
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, 1030, Austria
| | - Scott R. Manalis
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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2
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Abstract
While the involvement of actin polymerization in cell migration is well-established, much less is known about the role of transmembrane water flow in cell motility. Here, we investigate the role of water influx in a prototypical migrating cell, the neutrophil, which undergoes rapid, directed movement to sites of injury, and infection. Chemoattractant exposure both increases cell volume and potentiates migration, but the causal link between these processes are not known. We combine single-cell volume measurements and a genome-wide CRISPR screen to identify the regulators of chemoattractant-induced neutrophil swelling, including NHE1, AE2, PI3K-gamma, and CA2. Through NHE1 inhibition in primary human neutrophils, we show that cell swelling is both necessary and sufficient for the potentiation of migration following chemoattractant stimulation. Our data demonstrate that chemoattractant-driven cell swelling complements cytoskeletal rearrangements to enhance migration speed.
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Affiliation(s)
- Tamas L Nagy
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Cardiovascular Research Institute, University of California, San FranciscoSan FranciscoUnited States
| | - Evelyn Strickland
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Cardiovascular Research Institute, University of California, San FranciscoSan FranciscoUnited States
| | - Orion D Weiner
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Cardiovascular Research Institute, University of California, San FranciscoSan FranciscoUnited States
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3
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Ni Q, Sun SX. Pump up the volume. eLife 2024; 13:e100032. [PMID: 38953882 PMCID: PMC11219035 DOI: 10.7554/elife.100032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024] Open
Abstract
An influx of water molecules can help immune cells called neutrophils to move to where they are needed in the body.
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Affiliation(s)
- Qin Ni
- Institute for NanoBioTechnology and Department of Mechanical Engineering, Johns Hopkins UniversityBaltimoreUnited States
| | - Sean X Sun
- Institute for NanoBioTechnology and Department of Mechanical Engineering, Johns Hopkins UniversityBaltimoreUnited States
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4
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Pennacchio FA, Poli A, Pramotton FM, Lavore S, Rancati I, Cinquanta M, Vorselen D, Prina E, Romano OM, Ferrari A, Piel M, Cosentino Lagomarsino M, Maiuri P. N2FXm, a method for joint nuclear and cytoplasmic volume measurements, unravels the osmo-mechanical regulation of nuclear volume in mammalian cells. Nat Commun 2024; 15:1070. [PMID: 38326317 PMCID: PMC10850064 DOI: 10.1038/s41467-024-45168-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 01/15/2024] [Indexed: 02/09/2024] Open
Abstract
In eukaryotes, cytoplasmic and nuclear volumes are tightly regulated to ensure proper cell homeostasis. However, current methods to measure cytoplasmic and nuclear volumes, including confocal 3D reconstruction, have limitations, such as relying on two-dimensional projections or poor vertical resolution. Here, to overcome these limitations, we describe a method, N2FXm, to jointly measure cytoplasmic and nuclear volumes in single cultured adhering human cells, in real time, and across cell cycles. We find that this method accurately provides joint size over dynamic measurements and at different time resolutions. Moreover, by combining several experimental perturbations and analyzing a mathematical model including osmotic effects and tension, we show that N2FXm can give relevant insights on how mechanical forces exerted by the cytoskeleton on the nuclear envelope can affect the growth of nucleus volume by biasing nuclear import. Our method, by allowing for accurate joint nuclear and cytoplasmic volume dynamic measurements at different time resolutions, highlights the non-constancy of the nucleus/cytoplasm ratio along the cell cycle.
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Affiliation(s)
- Fabrizio A Pennacchio
- IFOM ETS-The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
- Laboratory of Applied Mechanobiology, Department of Health Sciences and Technology, ETH Zurich, Vladimir-Prelog-Weg 4, 8093, Zurich, Switzerland
| | - Alessandro Poli
- IFOM ETS-The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Francesca Michela Pramotton
- Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, Zurich, CH-8092, Switzerland
| | - Stefania Lavore
- IFOM ETS-The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Ilaria Rancati
- IFOM ETS-The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Mario Cinquanta
- IFOM ETS-The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Daan Vorselen
- Department of Biology and Howard Hughes Medical Institute, University of Washington, Seattle, WA, 98105, USA
| | - Elisabetta Prina
- IFOM ETS-The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Orso Maria Romano
- IFOM ETS-The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Aldo Ferrari
- Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, Zurich, CH-8092, Switzerland
| | - Matthieu Piel
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005, Paris, France
- Institut Pierre-Gilles de Gennes, PSL Research University, F-75005, Paris, France
| | - Marco Cosentino Lagomarsino
- IFOM ETS-The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy
- Dipartimento di Fisica, Università degli Studi di Milano, and I.N.F.N., Via Celoria 16, 20133, Milan, Italy
| | - Paolo Maiuri
- IFOM ETS-The AIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy.
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Via S. Pansini 5, 80131, Naples, Italy.
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5
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Claude-Taupin A, Dupont N. To squeeze or not: Regulation of cell size by mechanical forces in development and human diseases. Biol Cell 2024; 116:e2200101. [PMID: 38059665 DOI: 10.1111/boc.202200101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 12/08/2023]
Abstract
Physical constraints, such as compression, shear stress, stretching and tension play major roles during development and tissue homeostasis. Mechanics directly impact physiology, and their alteration is also recognized as having an active role in driving human diseases. Recently, growing evidence has accumulated on how mechanical forces are translated into a wide panel of biological responses, including metabolism and changes in cell morphology. The aim of this review is to summarize and discuss our knowledge on the impact of mechanical forces on cell size regulation. Other biological consequences of mechanical forces will not be covered by this review. Moreover, wherever possible, we also discuss mechanosensors and molecular and cellular signaling pathways upstream of cell size regulation. We finally highlight the relevance of mechanical forces acting on cell size in physiology and human diseases.
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Affiliation(s)
- Aurore Claude-Taupin
- Institut Necker Enfants Malades (INEM), INSERM UMR-S1151, CNRS UMR-S8253, Université Paris Cité, Paris, France
| | - Nicolas Dupont
- Institut Necker Enfants Malades (INEM), INSERM UMR-S1151, CNRS UMR-S8253, Université Paris Cité, Paris, France
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6
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Liu X, Oh S, Kirschner MW. The uniformity and stability of cellular mass density in mammalian cell culture. Front Cell Dev Biol 2022; 10:1017499. [PMID: 36313562 PMCID: PMC9597509 DOI: 10.3389/fcell.2022.1017499] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 09/23/2022] [Indexed: 12/04/2022] Open
Abstract
Cell dry mass is principally determined by the sum of biosynthesis and degradation. Measurable change in dry mass occurs on a time scale of hours. By contrast, cell volume can change in minutes by altering the osmotic conditions. How changes in dry mass and volume are coupled is a fundamental question in cell size control. If cell volume were proportional to cell dry mass during growth, the cell would always maintain the same cellular mass density, defined as cell dry mass dividing by cell volume. The accuracy and stability against perturbation of this proportionality has never been stringently tested. Normalized Raman Imaging (NoRI), can measure both protein and lipid dry mass density directly. Using this new technique, we have been able to investigate the stability of mass density in response to pharmaceutical and physiological perturbations in three cultured mammalian cell lines. We find a remarkably narrow mass density distribution within cells, that is, significantly tighter than the variability of mass or volume distribution. The measured mass density is independent of the cell cycle. We find that mass density can be modulated directly by extracellular osmolytes or by disruptions of the cytoskeleton. Yet, mass density is surprisingly resistant to pharmacological perturbations of protein synthesis or protein degradation, suggesting there must be some form of feedback control to maintain the homeostasis of mass density when mass is altered. By contrast, physiological perturbations such as starvation or senescence induce significant shifts in mass density. We have begun to shed light on how and why cell mass density remains fixed against some perturbations and yet is sensitive during transitions in physiological state.
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Affiliation(s)
| | | | - Marc W. Kirschner
- Department of Systems Biology, Harvard Medical School, Boston, MA, United States
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7
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Abstract
The most fundamental feature of cellular form is size, which sets the scale of all cell biological processes. Growth, form, and function are all necessarily linked in cell biology, but we often do not understand the underlying molecular mechanisms nor their specific functions. Here, we review progress toward determining the molecular mechanisms that regulate cell size in yeast, animals, and plants, as well as progress toward understanding the function of cell size regulation. It has become increasingly clear that the mechanism of cell size regulation is deeply intertwined with basic mechanisms of biosynthesis, and how biosynthesis can be scaled (or not) in proportion to cell size. Finally, we highlight recent findings causally linking aberrant cell size regulation to cellular senescence and their implications for cancer therapies.
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Affiliation(s)
- Shicong Xie
- Department of Biology, Stanford University, Stanford, California, USA;
| | - Matthew Swaffer
- Department of Biology, Stanford University, Stanford, California, USA;
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, California, USA;
- Chan Zuckerberg Biohub, San Francisco, California, USA
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8
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Fuest S, Post C, Balbach ST, Jabar S, Neumann I, Schimmelpfennig S, Sargin S, Nass E, Budde T, Kailayangiri S, Altvater B, Ranft A, Hartmann W, Dirksen U, Rössig C, Schwab A, Pethő Z. Relevance of Abnormal KCNN1 Expression and Osmotic Hypersensitivity in Ewing Sarcoma. Cancers (Basel) 2022; 14:4819. [PMID: 36230742 PMCID: PMC9564116 DOI: 10.3390/cancers14194819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/27/2022] [Accepted: 09/29/2022] [Indexed: 12/02/2022] Open
Abstract
Ewing sarcoma (EwS) is a rare and highly malignant bone tumor occurring mainly in childhood and adolescence. Physiologically, the bone is a central hub for Ca2+ homeostasis, which is severely disturbed by osteolytic processes in EwS. Therefore, we aimed to investigate how ion transport proteins involved in Ca2+ homeostasis affect EwS pathophysiology. We characterized the expression of 22 candidate genes of Ca2+-permeable or Ca2+-regulated ion channels in three EwS cell lines and found the Ca2+-activated K+ channel KCa2.1 (KCNN1) to be exceptionally highly expressed. We revealed that KCNN1 expression is directly regulated by the disease-driving oncoprotein EWSR1-FL1. Due to its consistent overexpression in EwS, KCNN1 mRNA could be a prognostic marker in EwS. In a large cohort of EwS patients, however, KCNN1 mRNA quantity does not correlate with clinical parameters. Several functional studies including patch clamp electrophysiology revealed no evidence for KCa2.1 function in EwS cells. Thus, elevated KCNN1 expression is not translated to KCa2.1 channel activity in EwS cells. However, we found that the low K+ conductance of EwS cells renders them susceptible to hypoosmotic solutions. The absence of a relevant K+ conductance in EwS thereby provides an opportunity for hypoosmotic therapy that can be exploited during tumor surgery.
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Affiliation(s)
- Sebastian Fuest
- Institute of Physiology II, University Münster, 48149 Münster, Germany
| | - Christoph Post
- Institute of Physiology II, University Münster, 48149 Münster, Germany
| | - Sebastian T Balbach
- Department of Pediatric Hematology and Oncology, University Children's Hospital Münster, 48149 Münster, Germany
| | - Susanne Jabar
- Pediatrics III, University Hospital Essen, 45147 Essen, Germany
| | - Ilka Neumann
- Institute of Physiology II, University Münster, 48149 Münster, Germany
| | | | - Sarah Sargin
- Institute of Physiology II, University Münster, 48149 Münster, Germany
| | - Elke Nass
- Institute of Physiology I, University Münster, 48149 Münster, Germany
| | - Thomas Budde
- Institute of Physiology I, University Münster, 48149 Münster, Germany
| | - Sareetha Kailayangiri
- Department of Pediatric Hematology and Oncology, University Children's Hospital Münster, 48149 Münster, Germany
| | - Bianca Altvater
- Department of Pediatric Hematology and Oncology, University Children's Hospital Münster, 48149 Münster, Germany
| | - Andreas Ranft
- Pediatrics III, University Hospital Essen, 45147 Essen, Germany
| | - Wolfgang Hartmann
- Division of Translational Pathology, Gerhard-Domagk-Institute of Pathology, University Münster, 48149 Münster, Germany
| | - Uta Dirksen
- Pediatrics III, University Hospital Essen, 45147 Essen, Germany
| | - Claudia Rössig
- Department of Pediatric Hematology and Oncology, University Children's Hospital Münster, 48149 Münster, Germany
| | - Albrecht Schwab
- Institute of Physiology II, University Münster, 48149 Münster, Germany
| | - Zoltán Pethő
- Institute of Physiology II, University Münster, 48149 Münster, Germany
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9
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Garcia‐Herreros A, Yeh Y, Peng Z, del Álamo JC. Cyclic Mechanical Stresses Alter Erythrocyte Membrane Composition and Microstructure and Trigger Macrophage Phagocytosis. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2201481. [PMID: 35508805 PMCID: PMC9284186 DOI: 10.1002/advs.202201481] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Indexed: 06/01/2023]
Abstract
Red blood cells (RBCs) are cleared from the circulation when they become damaged or display aging signals targeted by macrophages. This process occurs mainly in the spleen, where blood flows through submicrometric constrictions called inter-endothelial slits (IES), subjecting RBCs to large-amplitude deformations. In this work, RBCs are circulated through microfluidic devices containing microchannels that replicate the IES. The cyclic mechanical stresses experienced by the cells affect their biophysical properties and molecular composition, accelerating cell aging. Specifically, RBCs quickly transition to a more spherical, less deformable phenotype that hinders microchannel passage, causing hemolysis. This transition is associated with the release of membrane vesicles, which self-extinguishes as the spacing between membrane-cytoskeleton linkers becomes tighter. Proteomics analysis of the mechanically aged RBCs reveals significant losses of essential proteins involved in antioxidant protection, gas transport, and cell metabolism. Finally, it is shown that these changes make mechanically aged RBCs more susceptible to macrophage phagocytosis. These results provide a comprehensive model explaining how physical stress induces RBC clearance in the spleen. The data also suggest new biomarkers of early "hemodamage" and inflammation preceding hemolysis in RBCs subjected to mechanical stress.
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Affiliation(s)
- Antoni Garcia‐Herreros
- Department of Mechanical and Aerospace EngineeringUniversity of California9500 Gilman Dr.La JollaCA92093USA
| | - Yi‐Ting Yeh
- Department of Mechanical and Aerospace EngineeringUniversity of California9500 Gilman Dr.La JollaCA92093USA
- Department of BioengineeringUniversity of California9500 Gilman Dr.La JollaCA92093USA
- Institute of Engineering in MedicineUniversity of California9500 Gilman Dr.La JollaCA92093USA
| | - Zhangli Peng
- Department of BioengineeringUniversity of Illinois at Chicago1200 W Harrison StChicagoIL60607USA
| | - Juan C. del Álamo
- Department of Mechanical and Aerospace EngineeringUniversity of California9500 Gilman Dr.La JollaCA92093USA
- Institute of Engineering in MedicineUniversity of California9500 Gilman Dr.La JollaCA92093USA
- Department of Mechanical EngineeringUniversity of Washington850 Republican StSeattleWA98109USA
- Center for Cardiovascular BiologyUniversity of Washington850 Republican StSeattleWA98109USA
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10
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García-Ruano D, Venkova L, Jain A, Ryan JC, Balasubramaniam VR, Piel M, Coudreuse D. Fluorescence exclusion: a rapid, accurate and powerful method for measuring yeast cell volume. J Cell Sci 2022; 135:275598. [PMID: 35662333 DOI: 10.1242/jcs.259392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 05/26/2022] [Indexed: 11/20/2022] Open
Abstract
Cells exist in an astonishing range of volumes across and within species. However, our understanding of cell size control remains limited, due in large part to the challenges associated with accurate determination of cell volume. Much of our comprehension of size regulation derives from yeast models, but even for these morphologically stereotypical cells, assessment of cell volume has mostly relied on proxies and extrapolations from two-dimensional measurements. Recently, the fluorescence exclusion method (FXm) was developed to evaluate the size of mammalian cells, but whether it could be applied to smaller cells remained unknown. Using specifically designed microfluidic chips and an improved data analysis pipeline, we show here that FXm reliably detects subtle differences in the volume of fission yeast cells, even for those with altered shapes. Moreover, it allows for the monitoring of dynamic volume changes at the single-cell level with high time resolution. Collectively, our work highlights how the coupling of FXm with yeast genetics will bring new insights into the complex biology of cell growth.
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Affiliation(s)
- Daniel García-Ruano
- Institute of Genetics and Development of Rennes, UMR 6290, CNRS - University of Rennes 1, France
| | - Larisa Venkova
- Institut Curie and Institut Pierre Gilles de Gennes, PSL Research University, CNRS UMR 144, Paris, France.,Institute of Biochemistry and Cellular Genetics, CNRS UMR 5095, Bordeaux, France
| | - Akanksha Jain
- Institute of Genetics and Development of Rennes, UMR 6290, CNRS - University of Rennes 1, France
| | - Joseph C Ryan
- Institute of Genetics and Development of Rennes, UMR 6290, CNRS - University of Rennes 1, France
| | | | - Matthieu Piel
- Institut Curie and Institut Pierre Gilles de Gennes, PSL Research University, CNRS UMR 144, Paris, France
| | - Damien Coudreuse
- Institute of Genetics and Development of Rennes, UMR 6290, CNRS - University of Rennes 1, France.,Institute of Biochemistry and Cellular Genetics, CNRS UMR 5095, Bordeaux, France
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11
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Pimm ML, Liu X, Tuli F, Heritz J, Lojko A, Henty-Ridilla JL. Visualizing molecules of functional human profilin. eLife 2022; 11:e76485. [PMID: 35666129 PMCID: PMC9249392 DOI: 10.7554/elife.76485] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 06/06/2022] [Indexed: 11/20/2022] Open
Abstract
Profilin-1 (PFN1) is a cytoskeletal protein that regulates the dynamics of actin and microtubule assembly. Thus, PFN1 is essential for the normal division, motility, and morphology of cells. Unfortunately, conventional fusion and direct labeling strategies compromise different facets of PFN1 function. As a consequence, the only methods used to determine known PFN1 functions have been indirect and often deduced in cell-free biochemical assays. We engineered and characterized two genetically encoded versions of tagged PFN1 that behave identical to each other and the tag-free protein. In biochemical assays purified proteins bind to phosphoinositide lipids, catalyze nucleotide exchange on actin monomers, stimulate formin-mediated actin filament assembly, and bound tubulin dimers (kD = 1.89 µM) to impact microtubule dynamics. In PFN1-deficient mammalian cells, Halo-PFN1 or mApple-PFN1 (mAp-PEN1) restored morphological and cytoskeletal functions. Titrations of self-labeling Halo-ligands were used to visualize molecules of PFN1. This approach combined with specific function-disrupting point-mutants (Y6D and R88E) revealed PFN1 bound to microtubules in live cells. Cells expressing the ALS-associated G118V disease variant did not associate with actin filaments or microtubules. Thus, these tagged PFN1s are reliable tools for studying the dynamic interactions of PFN1 with actin or microtubules in vitro as well as in important cell processes or disease-states.
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Affiliation(s)
- Morgan L Pimm
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Xinbei Liu
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Farzana Tuli
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Jennifer Heritz
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Ashley Lojko
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Jessica L Henty-Ridilla
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
- Department of Neuroscience and Physiology, SUNY Upstate Medical UniversitySyracuseUnited States
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12
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Berry S, Müller M, Rai A, Pelkmans L. Feedback from nuclear RNA on transcription promotes robust RNA concentration homeostasis in human cells. Cell Syst 2022; 13:454-470.e15. [PMID: 35613616 DOI: 10.1016/j.cels.2022.04.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 12/13/2021] [Accepted: 04/21/2022] [Indexed: 12/18/2022]
Abstract
RNA concentration homeostasis involves coordinating RNA abundance and synthesis rates with cell size. Here, we study this in human cells by combining genome-wide perturbations with quantitative single-cell measurements. Despite relative ease in perturbing RNA synthesis, we find that RNA concentrations generally remain highly constant. Perturbations that would be expected to increase nuclear mRNA levels, including those targeting nuclear mRNA degradation or export, result in downregulation of RNA synthesis. This is associated with reduced abundance of transcription-associated proteins and protein states that are normally coordinated with RNA production in single cells, including RNA polymerase II (RNA Pol II) itself. Acute perturbations, elevation of nuclear mRNA levels, and mathematical modeling indicate that mammalian cells achieve robust mRNA concentration homeostasis by the mRNA-based negative feedback on transcriptional activity in the nucleus. This ultimately acts to coordinate RNA Pol II abundance with nuclear mRNA degradation and export rates and may underpin the scaling of mRNA abundance with cell size.
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Affiliation(s)
- Scott Berry
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland; EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.
| | - Micha Müller
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Arpan Rai
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Lucas Pelkmans
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.
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13
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Homan T, Monnier S, Jebane C, Nicolas A, Delanoë-Ayari H. Measuring the average cell size and width of its distribution in cellular tissues using Fourier transform. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2022; 45:44. [PMID: 35532848 DOI: 10.1140/epje/s10189-022-00198-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
Abstract
We present an in-depth investigation of a fully automated Fourier-based analysis to determine the cell size and the width of its distribution in 3D biological tissues. The results are thoroughly tested using generated images, and we offer valuable criteria for image acquisition settings to optimize accuracy. We demonstrate that the most important parameter is the number of cells in the field of view, and we show that accurate measurements can already be made on volume only containing [Formula: see text] cells. The resolution in z is also not so important, and a reduced number of in-depth images, of order of one per cell, already provides a measure of the mean cell size with less than 5% error. The technique thus appears to be a very promising tool for very fast live local volume cell measurement in 3D tissues in vivo while strongly limiting photobleaching and phototoxicity issues.
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Affiliation(s)
- Tess Homan
- Univ Lyon, Univ Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, 69622, Villeurbanne, France
| | - Sylvain Monnier
- Univ Lyon, Univ Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, 69622, Villeurbanne, France
| | - Cécile Jebane
- Univ Lyon, Univ Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, 69622, Villeurbanne, France
| | - Alice Nicolas
- Univ. Grenoble Alpes, CNRS, CEA/LETIMinatec, Grenoble INP, LTM, 38054, Grenoble, France
| | - Hélène Delanoë-Ayari
- Univ Lyon, Univ Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, 69622, Villeurbanne, France.
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14
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Venkova L, Vishen AS, Lembo S, Srivastava N, Duchamp B, Ruppel A, Williart A, Vassilopoulos S, Deslys A, Garcia Arcos JM, Diz-Muñoz A, Balland M, Joanny JF, Cuvelier D, Sens P, Piel M. A mechano-osmotic feedback couples cell volume to the rate of cell deformation. eLife 2022; 11:72381. [PMID: 35416768 PMCID: PMC9090331 DOI: 10.7554/elife.72381] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 04/08/2022] [Indexed: 11/13/2022] Open
Abstract
Mechanics has been a central focus of physical biology in the past decade. In comparison, how cells manage their size is less understood. Here we show that a parameter central to both the physics and the physiology of the cell, its volume, depends on a mechano-osmotic coupling. We found that cells change their volume depending on the rate at which they change shape, when they spontaneously spread are externally deformed. Cells undergo slow deformation at constant volume, while fast deformation leads to volume loss. We propose a mechano-sensitive pump and leak model to explain this phenomenon. Our model and experiments suggest that volume modulation depends on the state of the actin cortex and the coupling of ion fluxes to membrane tension. This mechano-osmotic coupling defines a membrane tension homeostasis module constantly at work in cells, causing volume fluctuations associated with fast cell shape changes, with potential consequences on cellular physiology.
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Affiliation(s)
- Larisa Venkova
- PSL Research University, Institut Curie, CNRS, UMR 144, Paris, France
| | - Amit Singh Vishen
- PSL Research University, Institut Curie, CNRS, UMR 144, Paris, France
| | - Sergio Lembo
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Nishit Srivastava
- PSL Research University, Institut Curie, CNRS, UMR 144, Paris, France
| | - Baptiste Duchamp
- PSL Research University, Institut Curie, CNRS, UMR 144, Paris, France
| | - Artur Ruppel
- Laboratoire Interdisciplinaire de Physique, Grenoble, France
| | - Alice Williart
- PSL Research University, Institut Curie, CNRS, UMR 144, Paris, France
| | | | - Alexandre Deslys
- PSL Research University, Institut Curie, CNRS, UMR 144, Paris, France
| | | | - Alba Diz-Muñoz
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Martial Balland
- Laboratoire Interdisciplinaire de Physique, Grenoble, France
| | | | - Damien Cuvelier
- PSL Research University, Institut Curie, CNRS, UMR 144, Paris, France
| | - Pierre Sens
- Laboratoire Physico Chimie Curie, Institut Curie, CNRS UMR168, Paris, France
| | - Matthieu Piel
- PSL Research University, Institut Curie, CNRS, UMR 144, Paris, France
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15
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Cadart C, Venkova L, Piel M, Cosentino Lagomarsino M. Volume growth in animal cells is cell cycle dependent and shows additive fluctuations. eLife 2022; 11:e70816. [PMID: 35088713 PMCID: PMC8798040 DOI: 10.7554/elife.70816] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 12/21/2021] [Indexed: 12/04/2022] Open
Abstract
The way proliferating animal cells coordinate the growth of their mass, volume, and other relevant size parameters is a long-standing question in biology. Studies focusing on cell mass have identified patterns of mass growth as a function of time and cell cycle phase, but little is known about volume growth. To address this question, we improved our fluorescence exclusion method of volume measurement (FXm) and obtained 1700 single-cell volume growth trajectories of HeLa cells. We find that, during most of the cell cycle, volume growth is close to exponential and proceeds at a higher rate in S-G2 than in G1. Comparing the data with a mathematical model, we establish that the cell-to-cell variability in volume growth arises from constant-amplitude fluctuations in volume steps rather than fluctuations of the underlying specific growth rate. We hypothesize that such 'additive noise' could emerge from the processes that regulate volume adaptation to biophysical cues, such as tension or osmotic pressure.
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Affiliation(s)
- Clotilde Cadart
- Institut Pierre-Gilles de Gennes, PSL Research UniversityParisFrance
- Institut Curie, PSL Research University, CNRSParisFrance
| | - Larisa Venkova
- Institut Pierre-Gilles de Gennes, PSL Research UniversityParisFrance
- Institut Curie, PSL Research University, CNRSParisFrance
| | - Matthieu Piel
- Institut Pierre-Gilles de Gennes, PSL Research UniversityParisFrance
- Institut Curie, PSL Research University, CNRSParisFrance
| | - Marco Cosentino Lagomarsino
- FIRC Institute of Molecular Oncology (IFOM)MilanItaly
- Physics Department, University of Milan, and INFNMilanItaly
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16
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Yan G, Monnier S, Mouelhi M, Dehoux T. Probing molecular crowding in compressed tissues with Brillouin light scattering. Proc Natl Acad Sci U S A 2022; 119:e2113614119. [PMID: 35046032 PMCID: PMC8795543 DOI: 10.1073/pnas.2113614119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/13/2021] [Indexed: 12/11/2022] Open
Abstract
Volume regulation is key in maintaining important tissue functions, such as growth or healing. This is achieved by modulation of active contractility as well as water efflux that changes molecular crowding within individual cells. Local sensors have been developed to monitor stresses or forces in model tissues, but these approaches do not capture the contribution of liquid flows to volume regulation. Here, we use a tool based on Brillouin light scattering (BLS) that uses the interaction of a laser light with inherent picosecond timescale density fluctuations in the sample. To investigate volume variations, we induced osmotic perturbations with a polysaccharide osmolyte, Dextran (Dx), and compress cells locally within multicellular spheroids (MCSs). During osmotic compressions, we observe an increase in the BLS frequency shift that reflects local variations in the compressibility. To elucidate these data, we propose a model based on a mixing law that describes the increase of molecular crowding upon reduction of the intracellular fluids. Comparison with the data suggests a nonlinear increase of the compressibility due to the dense crowding that induces hydrodynamic interactions between the cellular polymers.
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Affiliation(s)
- Guqi Yan
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Sylvain Monnier
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Malèke Mouelhi
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
| | - Thomas Dehoux
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
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17
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Dolega ME, Monnier S, Brunel B, Joanny JF, Recho P, Cappello G. Extracellular matrix in multicellular aggregates acts as a pressure sensor controlling cell proliferation and motility. eLife 2021; 10:63258. [PMID: 33704063 PMCID: PMC8064752 DOI: 10.7554/elife.63258] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 03/08/2021] [Indexed: 12/30/2022] Open
Abstract
Imposed deformations play an important role in morphogenesis and tissue homeostasis, both in normal and pathological conditions. To perceive mechanical perturbations of different types and magnitudes, tissues need appropriate detectors, with a compliance that matches the perturbation amplitude. By comparing results of selective osmotic compressions of CT26 mouse cells within multicellular aggregates and global aggregate compressions, we show that global compressions have a strong impact on the aggregates growth and internal cell motility, while selective compressions of same magnitude have almost no effect. Both compressions alter the volume of individual cells in the same way over a shor-timescale, but, by draining the water out of the extracellular matrix, the global one imposes a residual compressive mechanical stress on the cells over a long-timescale, while the selective one does not. We conclude that the extracellular matrix is as a sensor that mechanically regulates cell proliferation and migration in a 3D environment.
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Affiliation(s)
- Monika E Dolega
- Université Grenoble Alpes, Laboratoire Interdisciplinaire de Physique, CNRS, Grenoble, France
| | - Sylvain Monnier
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, VILLEURBANNE, France
| | - Benjamin Brunel
- Université Grenoble Alpes, Laboratoire Interdisciplinaire de Physique, CNRS, Grenoble, France
| | | | - Pierre Recho
- Université Grenoble Alpes, Laboratoire Interdisciplinaire de Physique, CNRS, Grenoble, France
| | - Giovanni Cappello
- Université Grenoble Alpes, Laboratoire Interdisciplinaire de Physique, CNRS, Grenoble, France
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18
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Braïni C, Bugnicourt G, Villard C. Neuronal growth from a volume perspective. Phys Biol 2021; 18:016007. [PMID: 33147573 DOI: 10.1088/1478-3975/abc79c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Microfluidic-based fluorescent exclusion method allows to tackle the issue of neuronal growth from a volume perspective. Based on this technology, we studied the two main actin-rich structures accompanying the early stages of neuron development, i.e. growth cones, located at the tip of growing neuronal processes, and propagative actin waves. Our work reveals that growth cones tend to loose volume during their forward motion, as do actin waves during their journey from the cell body to the tip of neuronal processes, before the total transfer of their remaining volume to the growth cone. Actin waves seem thus to supply material to increasingly distant growth cones as neurons develop. In addition, our work may suggest the existence of a membrane recycling phenomena associated to actin waves as a pulsatile anterograde source of material and by a continuous retrograde transport.
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Affiliation(s)
- Céline Braïni
- Physico-Chimie Curie, CNRS UMR 168, Université PSL, Sorbonne Université, Paris, France
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19
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Abstract
As cells grow, the size and number of their internal organelles increase in order to keep up with increased metabolic requirements. Abnormal size of organelles is a hallmark of cancer and an important aspect of diagnosis in cytopathology. Most organelles vary in either size or number, or both, as a function of cell size, but the mechanisms that create this variation remain unclear. In some cases, organelle size appears to scale with cell size through processes of relative growth, but in others the size may be set by either active measurement systems or genetic programs that instruct organelle biosynthetic activities to create organelles of a size appropriate to a given cell type.
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Affiliation(s)
- Wallace F Marshall
- Department of Biochemistry and Biophysics, University of California, San Francisco, California 94143, USA;
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20
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Mass measurements during lymphocytic leukemia cell polyploidization decouple cell cycle- and cell size-dependent growth. Proc Natl Acad Sci U S A 2020; 117:15659-15665. [PMID: 32581119 PMCID: PMC7355023 DOI: 10.1073/pnas.1922197117] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Cell size is believed to influence cell growth through limited transport efficiency in larger cells. However, this has not been experimentally investigated due to a lack of noninvasive, high-precision growth quantification methods suitable for measuring large cells. Here, we have engineered large versions of microfluidic mass sensors called suspended microchannel resonators in order to study the growth of single mammalian cells that range 100-fold in mass. Our measurements, which decouple growth effects caused by cell cycle and cell size, revealed that absolute cell size does not impose strict transport or other limitations that would inhibit growth and that cell cycle has a large influence on growth. Cell size is believed to influence cell growth and metabolism. Consistently, several studies have revealed that large cells have lower mass accumulation rates per unit mass (i.e., growth efficiency) than intermediate-sized cells in the same population. Size-dependent growth is commonly attributed to transport limitations, such as increased diffusion timescales and decreased surface-to-volume ratio. However, separating cell size- and cell cycle-dependent growth is challenging. To address this, we monitored growth efficiency of pseudodiploid mouse lymphocytic leukemia cells during normal proliferation and polyploidization. This was enabled by the development of large-channel suspended microchannel resonators that allow us to monitor buoyant mass of single cells ranging from 40 pg (small pseudodiploid cell) to over 4,000 pg, with a resolution ranging from ∼1% to ∼0.05%. We find that cell growth efficiency increases, plateaus, and then decreases as cell cycle proceeds. This growth behavior repeats with every endomitotic cycle as cells grow into polyploidy. Overall, growth efficiency changes 33% throughout the cell cycle. In contrast, increasing cell mass by over 100-fold during polyploidization did not change growth efficiency, indicating exponential growth. Consistently, growth efficiency remained constant when cell cycle was arrested in G2. Thus, cell cycle is a primary determinant of growth efficiency. As growth remains exponential over large size scales, our work finds no evidence for transport limitations that would decrease growth efficiency.
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21
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Rochman ND, Yao K, Gonzalez NPA, Wirtz D, Sun SX. Single Cell Volume Measurement Utilizing the Fluorescence Exclusion Method (FXm). Bio Protoc 2020; 10:e3652. [PMID: 33659322 DOI: 10.21769/bioprotoc.3652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 04/13/2020] [Accepted: 04/28/2020] [Indexed: 01/28/2023] Open
Abstract
The measurement of single cell size remains an obstacle towards a deeper understanding of cell growth control, tissue homeostasis, organogenesis, and a wide range of pathologies. Recent advances have placed a spotlight on the importance of cell volume in the regulation of fundamental cell signaling pathways including those known to orchestrate progression through the cell cycle. Here we provide our protocol for the Fluorescence Exclusion Method (FXm); references to the development of FXm; and a brief outlook on future advances in image analysis which may expand the range of problems studied utilizing FXm as well as lower the barrier to entry for groups interested in adding cell volume measurements into their experimental repertoire.
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Affiliation(s)
- Nash D Rochman
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Kai Yao
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Nicolas Perez A Gonzalez
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Denis Wirtz
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.,Physical Sciences in Oncology Center (PSOC), Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Sean X Sun
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.,Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.,Physical Sciences in Oncology Center (PSOC), Johns Hopkins University, Baltimore, Maryland 21218, USA
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22
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Model M. Comparison of cell volume measurements by fluorescence and absorption exclusion microscopy. J Microsc 2020; 280:12-18. [PMID: 32472565 DOI: 10.1111/jmi.12929] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 05/23/2020] [Accepted: 05/28/2020] [Indexed: 01/06/2023]
Abstract
There are two light microscopic methods for cell volume measurement based on volume exclusion. One method, sometimes referred to as FLEX, utilises negative staining by an external fluorescent dye, and cell volume is found from attenuation of fluorescence under a wide-field microscope. The other method (TTD) is based on exclusion of an external absorbing dye, resulting in an increased intensity of transmission image. In this work, we compared these two methods. TTD measurements were consistent, reproducible and identical to those obtained by confocal scanning. In our hands, FLEX based on either sodium fluorescein of fluorescent dextran, usually resulted in underestimation of cell volume, which were insignificant in shallow chambers but became more severe with increased chamber depth. We have not been able to exactly pinpoint the source of the problem; it may have been undetected accumulation of dye in the cells or, more likely, some unappreciated aspects of image formation under epi-illumination. We also discuss applicability of both methods to in-flow volume measurements. LAY DESCRIPTION: Cell volume is a parameter important for many cell biological and physiological applications, and many different methods have been proposed for its measurement. Two light microscopic methods based on volume exclusion deserve special attention due to their speed and simplicity. In one of them (transmission-through-dye, or TTD), cells are placed in a shallow chamber, and a strongly absorbing external dye is added to the cell-containing medium. The sample is imaged in transmission at a wavelength of maximum dye absorption. Because cells with intact membranes exclude the dye, they appear brighter on a transmission image, and their contrast quantitatively reflects cell thickness. By summation of thickness values over the cell area, cell volume can be obtained. The other method sometimes referred to as FLEX utilises exclusion of a fluorescent dye. Cells appear darker than the background under wide-field fluorescence observation in accordance with their thicknesses, and cell volume is computed by thickness summation over the area, like in TTD. In this work, we compared the accuracy of TTD and FLEX for volume measurements. TTD and confocal scanning produced virtually identical results, which suggests that TTD data are accurate. On the other hand, cell volumes measured by FLEX were consistently smaller than by TTD. The discrepancy always increased with the depth of the chamber, although the exact relationship varied between experiments. By contrast, TTD results were insensitive to chamber depth. Thus, it appears that FLEX underestimates cell volume. The reason for that is not entirely clear. Accumulation of the fluorescent dye inside the cell could be a possibility, although we found no evidence for that. Most likely, the reason lies with some unappreciated aspects of wide-field fluorescence image formation, which has not been well-characterised for the type of negative staining used in FLEX. In our opinion, TTD is the method of choice, at least for stationary cells. On the other hand, due to linear dependence of intensity on volume, FLEX might offer advantages for high-throughput flow volume imaging, although realisation of such an experiment has yet to be worked out.
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Affiliation(s)
- M Model
- Department of Biological Sciences, Kent State University, Kent, Ohio, U.S.A
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23
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Zatulovskiy E, Skotheim JM. On the Molecular Mechanisms Regulating Animal Cell Size Homeostasis. Trends Genet 2020; 36:360-372. [PMID: 32294416 PMCID: PMC7162994 DOI: 10.1016/j.tig.2020.01.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/28/2020] [Accepted: 01/28/2020] [Indexed: 12/19/2022]
Abstract
Cell size is fundamental to cell physiology because it sets the scale of intracellular geometry, organelles, and biosynthetic processes. In animal cells, size homeostasis is controlled through two phenomenologically distinct mechanisms. First, size-dependent cell cycle progression ensures that smaller cells delay cell cycle progression to accumulate more biomass than larger cells prior to cell division. Second, size-dependent cell growth ensures that larger and smaller cells grow slower per unit mass than more optimally sized cells. This decade has seen dramatic progress in single-cell technologies establishing the diverse phenomena of cell size control in animal cells. Here, we review this recent progress and suggest pathways forward to determine the underlying molecular mechanisms.
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Affiliation(s)
| | - Jan M Skotheim
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
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24
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Yao K, Rochman ND, Sun SX. CTRL - a label-free artificial intelligence method for dynamic measurement of single-cell volume. J Cell Sci 2020; 133:jcs.245050. [PMID: 32094267 DOI: 10.1242/jcs.245050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 02/10/2020] [Indexed: 12/27/2022] Open
Abstract
Measuring the physical size of a cell is valuable in understanding cell growth control. Current single-cell volume measurement methods for mammalian cells are labor intensive, inflexible and can cause cell damage. We introduce CTRL: Cell Topography Reconstruction Learner, a label-free technique incorporating the deep learning algorithm and the fluorescence exclusion method for reconstructing cell topography and estimating mammalian cell volume from differential interference contrast (DIC) microscopy images alone. The method achieves quantitative accuracy, requires minimal sample preparation, and applies to a wide range of biological and experimental conditions. The method can be used to track single-cell volume dynamics over arbitrarily long time periods. For HT1080 fibrosarcoma cells, we observe that the cell size at division is positively correlated with the cell size at birth (sizer), and there is a noticeable reduction in cell size fluctuations at 25% completion of the cell cycle in HT1080 fibrosarcoma cells.
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Affiliation(s)
- Kai Yao
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.,Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Nash D Rochman
- Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA.,Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sean X Sun
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA .,Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, USA.,Physical Sciences in Oncology Center (PSOC), Johns Hopkins University, Baltimore, MD 21218, USA
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25
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Pressure sensing through Piezo channels controls whether cells migrate with blebs or pseudopods. Proc Natl Acad Sci U S A 2020; 117:2506-2512. [PMID: 31964823 PMCID: PMC7007555 DOI: 10.1073/pnas.1905730117] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cells migrating within the body perform vital functions in development and for defense and repair of tissues. In this dense environment, cells encounter mechanical forces and constraints not experienced when moving under buffer, and, accordingly, many change how they move. We find that gentle squashing, which mimics mechanical resistance, causes cells to move using blebs—a form of projection driven by fluid pressure—rather than pseudopods. This behavior depends on the Piezo stretch-operated ion channel in the cell membrane and calcium fluxes into the cell. Piezo is highly conserved and is required for light touch sensation; this work extends its functions into migrating cells. Blebs and pseudopods can both power cell migration, with blebs often favored in tissues, where cells encounter increased mechanical resistance. To investigate how migrating cells detect and respond to mechanical forces, we used a “cell squasher” to apply uniaxial pressure to Dictyostelium cells chemotaxing under soft agarose. As little as 100 Pa causes a rapid (<10 s), sustained shift to movement with blebs rather than pseudopods. Cells are flattened under load and lose volume; the actin cytoskeleton is reorganized, with myosin II recruited to the cortex, which may pressurize the cytoplasm for blebbing. The transition to bleb-driven motility requires extracellular calcium and is accompanied by increased cytosolic calcium. It is largely abrogated in cells lacking the Piezo stretch-operated channel; under load, these cells persist in using pseudopods and chemotax poorly. We propose that migrating cells sense pressure through Piezo, which mediates calcium influx, directing movement with blebs instead of pseudopods.
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26
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Abstract
Physical stimuli are essential for the function of eukaryotic cells, and changes in physical signals are important elements in normal tissue development as well as in disease initiation and progression. The complexity of physical stimuli and the cellular signals they initiate are as complex as those triggered by chemical signals. One of the most important, and the focus of this review, is the effect of substrate mechanical properties on cell structure and function. The past decade has produced a nearly exponentially increasing number of mechanobiological studies to define how substrate stiffness alters cell biology using both purified systems and intact tissues. Here we attempt to identify common features of mechanosensing in different systems while also highlighting the numerous informative exceptions to what in early studies appeared to be simple rules by which cells respond to mechanical stresses.
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Affiliation(s)
- Paul A Janmey
- Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Bioengineering, University of California-Berkeley, Berkeley, California; and Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Daniel A Fletcher
- Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Bioengineering, University of California-Berkeley, Berkeley, California; and Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Cynthia A Reinhart-King
- Department of Physiology, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Bioengineering, University of California-Berkeley, Berkeley, California; and Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
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27
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Funk J, Merino F, Venkova L, Heydenreich L, Kierfeld J, Vargas P, Raunser S, Piel M, Bieling P. Profilin and formin constitute a pacemaker system for robust actin filament growth. eLife 2019; 8:50963. [PMID: 31647411 PMCID: PMC6867828 DOI: 10.7554/elife.50963] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
The actin cytoskeleton drives many essential biological processes, from cell morphogenesis to motility. Assembly of functional actin networks requires control over the speed at which actin filaments grow. How this can be achieved at the high and variable levels of soluble actin subunits found in cells is unclear. Here we reconstitute assembly of mammalian, non-muscle actin filaments from physiological concentrations of profilin-actin. We discover that under these conditions, filament growth is limited by profilin dissociating from the filament end and the speed of elongation becomes insensitive to the concentration of soluble subunits. Profilin release can be directly promoted by formin actin polymerases even at saturating profilin-actin concentrations. We demonstrate that mammalian cells indeed operate at the limit to actin filament growth imposed by profilin and formins. Our results reveal how synergy between profilin and formins generates robust filament growth rates that are resilient to changes in the soluble subunit concentration.
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Affiliation(s)
- Johanna Funk
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Felipe Merino
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | | | | | - Jan Kierfeld
- Physics Department, TU Dortmund University, Dortmund, Germany
| | | | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | | | - Peter Bieling
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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28
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Perez-Gonzalez NA, Rochman ND, Yao K, Tao J, Le MTT, Flanary S, Sablich L, Toler B, Crentsil E, Takaesu F, Lambrus B, Huang J, Fu V, Chengappa P, Jones TM, Holland AJ, An S, Wirtz D, Petrie RJ, Guan KL, Sun SX. YAP and TAZ regulate cell volume. J Cell Biol 2019; 218:3472-3488. [PMID: 31481532 PMCID: PMC6781432 DOI: 10.1083/jcb.201902067] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/29/2019] [Accepted: 08/01/2019] [Indexed: 01/08/2023] Open
Abstract
How mammalian cells regulate their physical size is currently poorly understood, in part due to the difficulty in accurately quantifying cell volume in a high-throughput manner. Here, using the fluorescence exclusion method, we demonstrate that the mechanosensitive transcriptional regulators YAP (Yes-associated protein) and TAZ (transcriptional coactivator with PDZ-binding motif) are regulators of single-cell volume. The role of YAP/TAZ in volume regulation must go beyond its influence on total cell cycle duration or cell shape to explain the observed changes in volume. Moreover, for our experimental conditions, volume regulation by YAP/TAZ is independent of mTOR. Instead, we find that YAP/TAZ directly impacts the cell division volume, and YAP is involved in regulating intracellular cytoplasmic pressure. Based on the idea that YAP/TAZ is a mechanosensor, we find that inhibiting myosin assembly and cell tension slows cell cycle progression from G1 to S. These results suggest that YAP/TAZ may be modulating cell volume in combination with cytoskeletal tension during cell cycle progression.
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Affiliation(s)
| | - Nash D Rochman
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
| | - Kai Yao
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD
| | - Jiaxiang Tao
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD
| | - Minh-Tam Tran Le
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
| | - Shannon Flanary
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
| | - Lucia Sablich
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
| | - Ben Toler
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
| | - Eliana Crentsil
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
| | - Felipe Takaesu
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
| | - Bram Lambrus
- Department of Molecular Biology and Genetics, Johns Hopkins University, School of Medicine, Baltimore, MD
| | - Jessie Huang
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Vivian Fu
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, La Jolla, CA
| | | | - Tia M Jones
- Department of Biology, Drexel University, Philadelphia, PA
| | - Andrew J Holland
- Department of Molecular Biology and Genetics, Johns Hopkins University, School of Medicine, Baltimore, MD
| | - Steven An
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Denis Wirtz
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
- Physical Sciences in Oncology Center, Johns Hopkins University, Baltimore, MD
| | - Ryan J Petrie
- Department of Biology, Drexel University, Philadelphia, PA
| | - Kun-Liang Guan
- Department of Pharmacology and Moores Cancer Center, University of California, San Diego, La Jolla, CA
| | - Sean X Sun
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD
- Physical Sciences in Oncology Center, Johns Hopkins University, Baltimore, MD
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29
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Cadart C, Monnier S, Grilli J, Sáez PJ, Srivastava N, Attia R, Terriac E, Baum B, Cosentino-Lagomarsino M, Piel M. Size control in mammalian cells involves modulation of both growth rate and cell cycle duration. Nat Commun 2018; 9:3275. [PMID: 30115907 PMCID: PMC6095894 DOI: 10.1038/s41467-018-05393-0] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 06/30/2018] [Indexed: 02/04/2023] Open
Abstract
Despite decades of research, how mammalian cell size is controlled remains unclear because of the difficulty of directly measuring growth at the single-cell level. Here we report direct measurements of single-cell volumes over entire cell cycles on various mammalian cell lines and primary human cells. We find that, in a majority of cell types, the volume added across the cell cycle shows little or no correlation to cell birth size, a homeostatic behavior called "adder". This behavior involves modulation of G1 or S-G2 duration and modulation of growth rate. The precise combination of these mechanisms depends on the cell type and the growth condition. We have developed a mathematical framework to compare size homeostasis in datasets ranging from bacteria to mammalian cells. This reveals that a near-adder behavior is the most common type of size control and highlights the importance of growth rate modulation to size control in mammalian cells.
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Affiliation(s)
- Clotilde Cadart
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005, Paris, France
- Institut Pierre-Gilles de Gennes, PSL Research University, F-75005, Paris, France
| | - Sylvain Monnier
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005, Paris, France
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622, Villeurbanne, France
| | - Jacopo Grilli
- Department of Ecology and Evolution, University of Chicago, 1101 E 57th Street, Chicago, IL, 60637, USA
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM, 87501, USA
| | - Pablo J Sáez
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005, Paris, France
- Institut Pierre-Gilles de Gennes, PSL Research University, F-75005, Paris, France
| | - Nishit Srivastava
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005, Paris, France
- Institut Pierre-Gilles de Gennes, PSL Research University, F-75005, Paris, France
| | - Rafaele Attia
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005, Paris, France
- Institut Pierre-Gilles de Gennes, PSL Research University, F-75005, Paris, France
| | - Emmanuel Terriac
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005, Paris, France
- INM-Leibniz Institute for New Materials, Campus D2 2, 66123, Saarbrücken, Germany
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, UCL, London, WC1E 6BT, UK
- Institute of Physics of Living Systems, UCL, London, WC1E 6BT, UK
| | - Marco Cosentino-Lagomarsino
- Sorbonne Universités, Université Pierre et Marie Curie, Paris, F-75005, France.
- CNRS, UMR 7238 Computational and Quantitative Biology, Paris, F-75005, France.
- FIRC Institute of Molecular Oncology (IFOM), Milan, 20139, Italy.
| | - Matthieu Piel
- Institut Curie, PSL Research University, CNRS, UMR 144, F-75005, Paris, France.
- Institut Pierre-Gilles de Gennes, PSL Research University, F-75005, Paris, France.
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30
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Perez Gonzalez N, Tao J, Rochman ND, Vig D, Chiu E, Wirtz D, Sun SX. Cell tension and mechanical regulation of cell volume. Mol Biol Cell 2018; 29:0. [PMID: 30113884 PMCID: PMC6254581 DOI: 10.1091/mbc.e18-04-0213] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Animal cells use an unknown mechanism to control their growth and physical size. Here, using the fluorescence exclusion method, we measure cell volume for adherent cells on substrates of varying stiffness. We discover that the cell volume has a complex dependence on substrate stiffness and is positively correlated with the size of the cell adhesion to the substrate. From a mechanical force–balance condition that determines the geometry of the cell surface, we find that the observed cell volume variation can be predicted quantitatively from the distribution of active myosin through the cell cortex. To connect cell mechanical tension with cell size homeostasis, we quantified the nuclear localization of YAP/TAZ, a transcription factor involved in cell growth and proliferation. We find that the level of nuclear YAP/TAZ is positively correlated with the average cell volume. Moreover, the level of nuclear YAP/TAZ is also connected to cell tension, as measured by the amount of phosphorylated myosin. Cells with greater apical tension tend to have higher levels of nuclear YAP/TAZ and a larger cell volume. These results point to a size-sensing mechanism based on mechanical tension: the cell tension increases as the cell grows, and increasing tension feeds back biochemically to growth and proliferation control.
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Affiliation(s)
- Nicolas Perez Gonzalez
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Jiaxiang Tao
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Nash D Rochman
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Dhruv Vig
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Evelyn Chiu
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Denis Wirtz
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218.,Physical Sciences in Oncology Center (PSOC), Johns Hopkins University, Baltimore, MD 21218
| | - Sean X Sun
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218.,Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218.,Physical Sciences in Oncology Center (PSOC), Johns Hopkins University, Baltimore, MD 21218
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31
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Ginzberg MB, Chang N, D'Souza H, Patel N, Kafri R, Kirschner MW. Cell size sensing in animal cells coordinates anabolic growth rates and cell cycle progression to maintain cell size uniformity. eLife 2018; 7:26957. [PMID: 29889021 PMCID: PMC6031432 DOI: 10.7554/elife.26957] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 06/07/2018] [Indexed: 12/30/2022] Open
Abstract
Cell size uniformity in healthy tissues suggests that control mechanisms might coordinate cell growth and division. We derived a method to assay whether cellular growth rates depend on cell size, by monitoring how variance in size changes as cells grow. Our data revealed that, twice during the cell cycle, growth rates are selectively increased in small cells and reduced in large cells, ensuring cell size uniformity. This regulation was also observed directly by monitoring nuclear growth in live cells. We also detected cell-size-dependent adjustments of G1 length, which further reduce variability. Combining our assays with chemical/genetic perturbations confirmed that cells employ two strategies, adjusting both cell cycle length and growth rate, to maintain the appropriate size. Additionally, although Rb signaling is not required for these regulatory behaviors, perturbing Cdk4 activity still influences cell size, suggesting that the Cdk4 pathway may play a role in designating the cell’s target size. Animal cells come in many different sizes. In humans, for example, egg cells are thousands of times larger than sperm cells. Yet cells of any given type are often strikingly similar in size. The cells that line the surface of organs including the skin and kidneys are especially uniform; in fact a loss of size uniformity in certain tumors is a sign of malignancy. What kind of regulation could enable separate cells within a tissue to have the same size? One possibility is that each type of cell is programmed with a specific target size, and that a cell can sense if it strays from its target and take steps to compensate. Animal cells sensing their own size was first reported in the 1960s, and now Ginzberg et al. confirm that human cells grown in the laboratory do indeed monitor their size and correct deviations from their target. It turns out that two separate and independent processes help to keep all the cells in the population roughly uniform in size. Firstly, proliferating human cells that are smaller than their target size spend longer growing before they divide. Secondly, at two time points between cell divisions, large cells adjust their growth rate such that they grow slower than small cells. To show these processes in action, Ginzberg et al. introduced mutations or chemicals that perturbed the length of time between cell divisions or the rate of a cell’s growth. As expected, most of these perturbations had only a modest influence on cell size, due to the cell’s compensatory strategies. Cells that had less time to grow compensated by more quickly making new protein molecules, meaning that they still had enough material to build two new cells by the time they had to divide. In contrast, if a cell’s division was artificially delayed, it reduced its growth rate to stop it from becoming too large. Similarly, cells grown in conditions that slow the production of proteins extended the time between their cell divisions to give them enough time to accumulate the material required for two new cells. In a recent related study, Liu, Ginzberg et al. identified some of the molecules that a human cell uses to sense its own size. Together these two studies now pave the road to answering a fundamental question in cell biology: what is the elusive cell size sensor? Understanding how cells sense their size will open a window onto how quantitative information is programmed, sensed and communicated within living cells. These findings will shed also new light onto how cells specialize into cell types of different sizes, and what happens when cells lose the ability to sense or regulate their size in diseases like cancers.
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Affiliation(s)
- Miriam Bracha Ginzberg
- Department of Systems Biology, Harvard Medical School, Boston, United States.,Cell Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Nancy Chang
- Cell Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Heather D'Souza
- Cell Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Nish Patel
- Cell Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Ran Kafri
- Cell Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Marc W Kirschner
- Department of Systems Biology, Harvard Medical School, Boston, United States
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32
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Roussel C, Monnier S, Dussiot M, Farcy E, Hermine O, Le Van Kim C, Colin Y, Piel M, Amireault P, Buffet PA. Fluorescence Exclusion: A Simple Method to Assess Projected Surface, Volume and Morphology of Red Blood Cells Stored in Blood Bank. Front Med (Lausanne) 2018; 5:164. [PMID: 29900172 PMCID: PMC5989133 DOI: 10.3389/fmed.2018.00164] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 05/08/2018] [Indexed: 12/26/2022] Open
Abstract
Red blood cells (RBC) ability to circulate is closely related to their surface area-to-volume ratio. A decrease in this ratio induces a decrease in RBC deformability that can lead to their retention and elimination in the spleen. We recently showed that a subpopulation of “small RBC” with reduced projected surface area accumulated upon storage in blood bank concentrates, but data on the volume of these altered RBC are lacking. So far, single cell measurement of RBC volume has remained a challenging task achieved by a few sophisticated methods some being subject to potential artifacts. We aimed to develop a reproducible and ergonomic method to assess simultaneously RBC volume and morphology at the single cell level. We adapted the fluorescence exclusion measurement of volume in nucleated cells to the measurement of RBC volume. This method requires no pre-treatment of the cell and can be performed in physiological or experimental buffer. In addition to RBC volume assessment, brightfield images enabling a precise definition of the morphology and the measurement of projected surface area can be generated simultaneously. We first verified that fluorescence exclusion is precise, reproducible and can quantify volume modifications following morphological changes induced by heating or incubation in non-physiological medium. We then used the method to characterize RBC stored for 42 days in SAG-M in blood bank conditions. Simultaneous determination of the volume, projected surface area and morphology allowed to evaluate the surface area-to-volume ratio of individual RBC upon storage. We observed a similar surface area-to-volume ratio in discocytes (D) and echinocytes I (EI), which decreased in EII (7%) and EIII (24%), sphero-echinocytes (SE; 41%) and spherocytes (S; 47%). If RBC dimensions determine indeed the ability of RBC to cross the spleen, these modifications are expected to induce the rapid splenic entrapment of the most morphologically altered RBC (EIII, SE, and S) and further support the hypothesis of a rapid clearance of the “small RBC” subpopulation by the spleen following transfusion.
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Affiliation(s)
- Camille Roussel
- Biologie Intégrée du Globule Rouge UMR_S1134, Institut National de la Santé et de la Recherche Médicale, Université Paris Diderot, Sorbonne Paris Cité, Université de La Réunion, Université des Antilles, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratoire d'Excellence GR-Ex, Paris, France.,Université Paris Descartes, Paris, France.,Laboratory of Cellular and Molecular Mechanisms of Hematological Disorders and Therapeutic Implications U1163, Centre National de la Recherche Scientifique ERL 8254, Institut National de la Santé et de la Recherche Médicale, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Sylvain Monnier
- Institut Curie, Centre National de la Recherche Scientifique, UMR 144, PSL Research University, Paris, France
| | - Michael Dussiot
- Laboratoire d'Excellence GR-Ex, Paris, France.,Laboratory of Cellular and Molecular Mechanisms of Hematological Disorders and Therapeutic Implications U1163, Centre National de la Recherche Scientifique ERL 8254, Institut National de la Santé et de la Recherche Médicale, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | | | - Olivier Hermine
- Laboratoire d'Excellence GR-Ex, Paris, France.,Université Paris Descartes, Paris, France.,Laboratory of Cellular and Molecular Mechanisms of Hematological Disorders and Therapeutic Implications U1163, Centre National de la Recherche Scientifique ERL 8254, Institut National de la Santé et de la Recherche Médicale, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,Assistance Publique des Hôpitaux de Paris, Paris, France
| | - Caroline Le Van Kim
- Biologie Intégrée du Globule Rouge UMR_S1134, Institut National de la Santé et de la Recherche Médicale, Université Paris Diderot, Sorbonne Paris Cité, Université de La Réunion, Université des Antilles, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - Yves Colin
- Biologie Intégrée du Globule Rouge UMR_S1134, Institut National de la Santé et de la Recherche Médicale, Université Paris Diderot, Sorbonne Paris Cité, Université de La Réunion, Université des Antilles, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - Matthieu Piel
- Institut Curie, Centre National de la Recherche Scientifique, UMR 144, PSL Research University, Paris, France.,Institut Pierre-Gilles de Gennes, PSL Research University, Paris, France
| | - Pascal Amireault
- Biologie Intégrée du Globule Rouge UMR_S1134, Institut National de la Santé et de la Recherche Médicale, Université Paris Diderot, Sorbonne Paris Cité, Université de La Réunion, Université des Antilles, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratoire d'Excellence GR-Ex, Paris, France.,Laboratory of Cellular and Molecular Mechanisms of Hematological Disorders and Therapeutic Implications U1163, Centre National de la Recherche Scientifique ERL 8254, Institut National de la Santé et de la Recherche Médicale, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Pierre A Buffet
- Biologie Intégrée du Globule Rouge UMR_S1134, Institut National de la Santé et de la Recherche Médicale, Université Paris Diderot, Sorbonne Paris Cité, Université de La Réunion, Université des Antilles, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratoire d'Excellence GR-Ex, Paris, France.,Université Paris Descartes, Paris, France.,Assistance Publique des Hôpitaux de Paris, Paris, France
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33
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Braïni C, Mottolese A, Ferrante I, Monnier S, Villard C. High-resolution Volume Imaging of Neurons by the Use of Fluorescence eXclusion Method and Dedicated Microfluidic Devices. J Vis Exp 2018. [PMID: 29630044 PMCID: PMC5933246 DOI: 10.3791/56923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Volume is an important parameter regarding physiological and pathological characteristics of neurons at different time scales. Neurons are quite unique cells regarding their extended ramified morphologies and consequently raise several methodological challenges for volume measurement. In the particular case of in vitro neuronal growth, the chosen methodology should include sub-micrometric axial resolution combined with full-field observation on time scales from minutes to hours or days. Unlike other methods like cell shape reconstruction using confocal imaging, electrically-based measurements or Atomic Force Microscopy, the recently developed Fluorescence eXclusion method (FXm) has the potential to fulfill these challenges. However, although being simple in its principle, implementation of a high-resolution FXm for neurons requires multiple adjustments and a dedicated methodology. We present here a method based on the combination of fluorescence exclusion, low-roughness multi-compartments microfluidic devices, and finally micropatterning to achieve in vitro measurements of local neuronal volume. The high resolution provided by the device allowed us to measure the local volume of neuronal processes (neurites) and the volume of some specific structures involved in neuronal growth, such as growth cones (GCs).
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Affiliation(s)
- Céline Braïni
- Laboratoire Physico-Chimie Curie, Institut Curie, Institut Pierre-Gilles de Gennes pour la microfluidique, Université PSL, CNRS
| | - Angelo Mottolese
- Laboratoire Physico-Chimie Curie, Institut Curie, Institut Pierre-Gilles de Gennes pour la microfluidique, Université PSL, CNRS
| | - Ivan Ferrante
- Laboratoire Physico-Chimie Curie, Institut Curie, Institut Pierre-Gilles de Gennes pour la microfluidique, Université PSL, CNRS
| | | | - Catherine Villard
- Laboratoire Physico-Chimie Curie, Institut Curie, Institut Pierre-Gilles de Gennes pour la microfluidique, Université PSL, CNRS;
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