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Srivastava LK, Ehrlicher AJ. Sensing the squeeze: nuclear mechanotransduction in health and disease. Nucleus 2024; 15:2374854. [PMID: 38951951 PMCID: PMC11221475 DOI: 10.1080/19491034.2024.2374854] [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] [Received: 02/23/2024] [Accepted: 06/26/2024] [Indexed: 07/03/2024] Open
Abstract
The nucleus not only is a repository for DNA but also a center of cellular and nuclear mechanotransduction. From nuclear deformation to the interplay between mechanosensing components and genetic control, the nucleus is poised at the nexus of mechanical forces and cellular function. Understanding the stresses acting on the nucleus, its mechanical properties, and their effects on gene expression is therefore crucial to appreciate its mechanosensitive function. In this review, we examine many elements of nuclear mechanotransduction, and discuss the repercussions on the health of cells and states of illness. By describing the processes that underlie nuclear mechanosensation and analyzing its effects on gene regulation, the review endeavors to open new avenues for studying nuclear mechanics in physiology and diseases.
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Affiliation(s)
| | - Allen J. Ehrlicher
- Department of Bioengineering, McGill University, Montreal, Canada
- Department of Biomedical Engineering, McGill University, Montreal, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Canada
- Centre for Structural Biology, McGill University, Montreal, Canada
- Department of Mechanical Engineering, McGill University, Montreal, Canada
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal, Canada
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2
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Dickinson RB, Abolghasemzade S, Lele TP. Rethinking nuclear shaping: insights from the nuclear drop model. SOFT MATTER 2024. [PMID: 39105242 DOI: 10.1039/d4sm00683f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/07/2024]
Abstract
Changes in the nuclear shape caused by cellular shape changes are generally assumed to reflect an elastic deformation from a spherical nuclear shape. Recent evidence, however, suggests that the nuclear lamina, which forms the outer nuclear surface together with the nuclear envelope, possesses more area than that of a sphere of the same volume. This excess area manifests as folds/wrinkles in the nuclear surface in rounded cells and allows facile nuclear flattening during cell spreading without any changes in nuclear volume or surface area. When the lamina becomes smooth and taut, it is inextensible, and supports a surface tension. At this point, it is possible to mathematically calculate the limiting nuclear shape purely based on geometric considerations. In this paper, we provide a commentary on the "nuclear drop model" which seeks to integrate the above features. We outline its testable physical properties and explore its biological implications.
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Affiliation(s)
- Richard B Dickinson
- Department of Chemical Engineering, University of Florida, 1030 Center Drive, Gainesville, FL, 32611, USA.
| | - Samere Abolghasemzade
- Department of Biomedical Engineering, Texas A&M University, 101 Bizzell St., College Station, TX, 77843, USA.
| | - Tanmay P Lele
- Department of Biomedical Engineering, Texas A&M University, 101 Bizzell St., College Station, TX, 77843, USA.
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, 3122 TAMU, College Station, TX, 77843, USA
- Department of Translational Medical Sciences, Texas A&M University, 2121 W Holcombe St., Houston, TX, 77030, USA
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3
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Dickinson RB, Lele TP. Nuclear shapes are geometrically determined by the excess surface area of the nuclear lamina. Front Cell Dev Biol 2023; 11:1058727. [PMID: 37397244 PMCID: PMC10308086 DOI: 10.3389/fcell.2023.1058727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 05/30/2023] [Indexed: 07/04/2023] Open
Abstract
Introduction: Nuclei have characteristic shapes dependent on cell type, which are critical for proper cell function, and nuclei lose their distinct shapes in multiple diseases including cancer, laminopathies, and progeria. Nuclear shapes result from deformations of the sub-nuclear components-nuclear lamina and chromatin. How these structures respond to cytoskeletal forces to form the nuclear shape remains unresolved. Although the mechanisms regulating nuclear shape in human tissues are not fully understood, it is known that different nuclear shapes arise from cumulative nuclear deformations post-mitosis, ranging from the rounded morphologies that develop immediately after mitosis to the various nuclear shapes that roughly correspond to cell shape (e.g., elongated nuclei in elongated cells, flat nuclei in flat cells). Methods: We formulated a mathematical model to predict nuclear shapes of cells in various contexts under the geometric constraints of fixed cell volume, nuclear volume and lamina surface area. Nuclear shapes were predicted and compared to experiments for cells in various geometries, including isolated on a flat surface, on patterned rectangles and lines, within a monolayer, isolated in a well, or when the nucleus is impinging against a slender obstacle. Results and Discussion: The close agreement between predicted and experimental shapes demonstrates a simple geometric principle of nuclear shaping: the excess surface area of the nuclear lamina (relative to that of a sphere of the same volume) permits a wide range of highly deformed nuclear shapes under the constraints of constant surface area and constant volume. When the lamina is smooth (tensed), the nuclear shape can be predicted entirely from these geometric constraints alone for a given cell shape. This principle explains why flattened nuclear shapes in fully spread cells are insensitive to the magnitude of the cytoskeletal forces. Also, the surface tension in the nuclear lamina and nuclear pressure can be estimated from the predicted cell and nuclear shapes when the cell cortical tension is known, and the predictions are consistent with measured forces. These results show that excess surface area of the nuclear lamina is the key determinant of nuclear shapes. When the lamina is smooth (tensed), the nuclear shape can be determined purely by the geometric constraints of constant (but excess) nuclear surface area, nuclear volume, and cell volume, for a given cell adhesion footprint, independent of the magnitude of the cytoskeletal forces involved.
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Affiliation(s)
- Richard B. Dickinson
- Department of Chemical Engineering, University of Florida, Gainesville, FL, United States
| | - Tanmay P. Lele
- Department of Biomedical Engineering, College of Engineering, Texas A&M University College Station, College Station, TX, United States
- Artie McFerrin Department of Chemical Engineering, College of Engineering, Texas A&M University, College Station, TX, United States
- Department of Translational Medical Sciences, Texas A&M University, College Station, TX, United States
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4
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Katiyar A, Zhang J, Antani JD, Yu Y, Scott KL, Lele PP, Reinhart‐King CA, Sniadecki NJ, Roux KJ, Dickinson RB, Lele TP. The Nucleus Bypasses Obstacles by Deforming Like a Drop with Surface Tension Mediated by Lamin A/C. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2201248. [PMID: 35712768 PMCID: PMC9376816 DOI: 10.1002/advs.202201248] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Migrating cells must deform their stiff cell nucleus to move through pores and fibers in tissue. Lamin A/C is known to hinder cell migration by limiting nuclear deformation and passage through confining channels, but its role in nuclear deformation and passage through fibrous environments is less clear. Cell and nuclear migration through discrete, closely spaced, slender obstacles which mimic the mechanical properties of collagen fibers are studied. Nuclei bypass slender obstacles while preserving their overall morphology by deforming around them with deep local invaginations of little resisting force. The obstacles do not impede the nuclear trajectory and do not cause rupture of the nuclear envelope. Nuclei likewise deform around single collagen fibers in cells migrating in 3D collagen gels. In contrast to its limiting role in nuclear passage through confining channels, lamin A/C facilitates nuclear deformation and passage through fibrous environments; nuclei in lamin-null (Lmna-/- ) cells lose their overall morphology and become entangled on the obstacles. Analogous to surface tension-mediated deformation of a liquid drop, lamin A/C imparts a surface tension on the nucleus that allows nuclear invaginations with little mechanical resistance, preventing nuclear entanglement and allowing nuclear passage through fibrous environments.
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Affiliation(s)
- Aditya Katiyar
- Department of Biomedical EngineeringTexas A&M University101 Bizzell St.College StationTX77843USA
| | - Jian Zhang
- Department of Biomedical EngineeringVanderbilt University2301 Vanderbilt PlaceNashvilleTN37235USA
| | - Jyot D. Antani
- Artie McFerrin Department of Chemical EngineeringTexas A&M University3122 TAMUCollege StationTX77843USA
| | - Yifan Yu
- Department of Chemical EngineeringUniversity of Florida1030 Center DriveGainesvilleFL32611USA
| | - Kelsey L. Scott
- Enabling Technologies GroupSanford Research2301 East 60th St NSioux FallsSD57104USA
| | - Pushkar P. Lele
- Artie McFerrin Department of Chemical EngineeringTexas A&M University3122 TAMUCollege StationTX77843USA
| | - Cynthia A. Reinhart‐King
- Department of Biomedical EngineeringVanderbilt University2301 Vanderbilt PlaceNashvilleTN37235USA
| | - Nathan J. Sniadecki
- Department of Mechanical EngineeringDepartment of Lab Medicine and PathologyInstitute for Stem Cell and Regenerative MedicineCenter for Cardiac BiologyUniversity of WashingtonStevens Way, Box 352600SeattleWA98195USA
| | - Kyle J. Roux
- Enabling Technologies GroupSanford Research2301 East 60th St NSioux FallsSD57104USA
- Department of PediatricsSanford School of MedicineUniversity of South Dakota414 E Clark StVermillionSD57069USA
| | - Richard B. Dickinson
- Department of Chemical EngineeringUniversity of Florida1030 Center DriveGainesvilleFL32611USA
| | - Tanmay P. Lele
- Department of Biomedical EngineeringTexas A&M University101 Bizzell St.College StationTX77843USA
- Artie McFerrin Department of Chemical EngineeringTexas A&M University3122 TAMUCollege StationTX77843USA
- Department of Translational Medical SciencesTexas A&M University2121 W Holcombe St.HoustonTX77030USA
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5
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The nuclear import of the transcription factor MyoD is reduced in mesenchymal stem cells grown in a 3D micro-engineered niche. Sci Rep 2021; 11:3021. [PMID: 33542304 PMCID: PMC7862644 DOI: 10.1038/s41598-021-81920-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 01/11/2021] [Indexed: 12/21/2022] Open
Abstract
Smart biomaterials are increasingly being used to control stem cell fate in vitro by the recapitulation of the native niche microenvironment. By integrating experimental measurements with numerical models, we show that in mesenchymal stem cells grown inside a 3D synthetic niche both nuclear transport of a myogenic factor and the passive nuclear diffusion of a smaller inert protein are reduced. Our results also suggest that cell morphology modulates nuclear proteins import through a partition of the nuclear envelope surface, which is a thin but extremely permeable annular portion in cells cultured on 2D substrates. Therefore, our results support the hypothesis that in stem cell differentiation, the nuclear import of gene-regulating transcription factors is controlled by a strain-dependent nuclear envelope permeability, probably related to the reorganization of stretch-activated nuclear pore complexes.
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6
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López-Alonso I, Blázquez-Prieto J, Amado-Rodríguez L, González-López A, Astudillo A, Sánchez M, Huidobro C, López-Martínez C, Dos Santos CC, Albaiceta GM. Preventing loss of mechanosensation by the nuclear membranes of alveolar cells reduces lung injury in mice during mechanical ventilation. Sci Transl Med 2019; 10:10/456/eaam7598. [PMID: 30158154 DOI: 10.1126/scitranslmed.aam7598] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 08/30/2017] [Accepted: 01/25/2018] [Indexed: 01/08/2023]
Abstract
The nuclear membrane acts as a mechanosensor that drives cellular responses following changes in the extracellular environment. Mechanically ventilated lungs are exposed to an abnormally high mechanical load that may result in clinically relevant alveolar damage. We report that mechanical ventilation in mice increased the expression of Lamin-A, a major determinant of nuclear membrane stiffness, in alveolar epithelial cells. Lamin-A expression increased and nuclear membrane compliance decreased in human bronchial epithelial cells after a mechanical stretch stimulus and in a murine model of lung injury after positive-pressure ventilation. Reducing Lamin-A maturation by depletion of the protease-encoding gene Zmpste24 preserved alveolar nuclear membrane compliance after mechanical ventilation in mice. Ventilator-induced proapoptotic gene expression changes and lung injury were reduced in mice lacking Zmpste24 compared to wild-type control animals. Similarly, treatment with the human immunodeficiency virus protease inhibitors lopinavir and ritonavir reduced the accumulation of Lamin-A at nuclear membranes and preserved nuclear membrane compliance after mechanical ventilation, mimicking the protective phenotype of Zmpste24-/- animals. These results show that the pathophysiological response to lung mechanical stretch is sensed by the nuclear membranes of lung alveolar cells, and suggest that protease inhibitors might be effective in preventing ventilator-induced lung injury.
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Affiliation(s)
- Inés López-Alonso
- Área del Corazón, Hospital Universitario Central de Asturias, 33011 Oviedo, Spain.,Departamento de Biología Funcional, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, 33005 Oviedo, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, 33011 Oviedo, Spain.,Centro de Investigación Biomédica En Red-Enfermedades Respiratorias, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Jorge Blázquez-Prieto
- Área del Corazón, Hospital Universitario Central de Asturias, 33011 Oviedo, Spain.,Departamento de Biología Funcional, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, 33005 Oviedo, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, 33011 Oviedo, Spain.,Centro de Investigación Biomédica En Red-Enfermedades Respiratorias, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Laura Amado-Rodríguez
- Área del Corazón, Hospital Universitario Central de Asturias, 33011 Oviedo, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, 33011 Oviedo, Spain.,Centro de Investigación Biomédica En Red-Enfermedades Respiratorias, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Adrián González-López
- Centro de Investigación Biomédica En Red-Enfermedades Respiratorias, Instituto de Salud Carlos III, 28029 Madrid, Spain.,Department of Anesthesiology and Operative Intensive Care Medicine, Charité Universitätsmedizin, 10117 Berlin, Germany
| | - Aurora Astudillo
- Servicio de Anatomía Patológica, Hospital Universitario Central de Asturias, 33011 Oviedo, Spain.,Departamento de Cirugía y Especialidades Médicoquirúrgicas, Universidad de Oviedo, 33005 Oviedo, Spain
| | - Manuel Sánchez
- Área de Farmacología, Departamento de Medicina, Universidad de Oviedo, 33005 Oviedo, Spain
| | - Covadonga Huidobro
- Área del Corazón, Hospital Universitario Central de Asturias, 33011 Oviedo, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, 33011 Oviedo, Spain.,Centro de Investigación Biomédica En Red-Enfermedades Respiratorias, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Cecilia López-Martínez
- Departamento de Biología Funcional, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, 33005 Oviedo, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, 33011 Oviedo, Spain
| | - Claudia C Dos Santos
- Interdepartmental Division of Critical Care, Keenan Research Centre of the Li Ka Shing Knowledge Institute of St. Michael's Hospital, University of Toronto, Toronto, Ontario M5B 1WB, Canada
| | - Guillermo M Albaiceta
- Área del Corazón, Hospital Universitario Central de Asturias, 33011 Oviedo, Spain. .,Departamento de Biología Funcional, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, 33005 Oviedo, Spain.,Instituto de Investigación Sanitaria del Principado de Asturias, 33011 Oviedo, Spain.,Centro de Investigación Biomédica En Red-Enfermedades Respiratorias, Instituto de Salud Carlos III, 28029 Madrid, Spain
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7
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Monticelli M, Jokhun DS, Petti D, Shivashankar GV, Bertacco R. Localized mechanical stimulation of single cells with engineered spatio-temporal profile. LAB ON A CHIP 2018; 18:2955-2965. [PMID: 30129955 DOI: 10.1039/c8lc00393a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In vivo, cells are frequently exposed to multiple mechanical stimuli arising from the extracellular microenvironment, with a deep impact on many biological functions. On the other hand, current methods for mechanobiology do not allow one to easily replicate in vitro the complex spatio-temporal profile of such mechanical signals. Here we introduce a new platform for studying the mechanical coupling between single cells and a dynamic extracellular environment, based on active substrates for cell culture made of Fe-coated polymeric micropillars. Under the action of quasi-static external magnetic fields, each group of pillars produces synchronous mechanical stimuli at different points of the cell membrane, thanks to the highly controllable pillars' deflection. This method allows one to apply complex stress fields, resulting in the parallel application of localized forces with tunable intensity and temporal profile. The platform has been validated by studying the cellular response to periodic stimuli in NIH3T3 fibroblasts. We find that low-frequency mechanical stimulation affects the actin cytoskeleton, nuclear morphology, and H2B core-histone dynamics and induces MKL transcription-cofactor translocation from nucleus to cytoplasm. The unique capability of the proposed platform to apply stimuli with a tunable temporal profile and high parallelism on a cell culture holds great potential for the investigation of mechanotransduction mechanisms in cells and tissues.
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Affiliation(s)
- M Monticelli
- Department of Physics, Politecnico di Milano, Milan, Italy.
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8
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Abstract
Stem cells are characterized by their self-renewal and multi-lineage differentiation potential. Stem cell differentiation is a prerequisite for the application of stem cells in regenerative medicine and clinical therapy. In addition to chemical stimulation, mechanical cues play a significant role in regulating stem cell differentiation. The integrity of mechanical sensors is necessary for the ability of cells to respond to mechanical signals. The nucleus, the largest and stiffest cellular organelle, interacts with the cytoskeleton as a key mediator of cell mechanics. Nuclear mechanics are involved in the complicated interactions of lamins, chromatin and nucleoskeleton-related proteins. Thus, stem cell differentiation is intimately associated with nuclear mechanics due to its indispensable role in mechanotransduction and mechanical response. This paper reviews several main contributions of nuclear mechanics, highlights the hallmarks of the nuclear mechanics of stem cells, and provides insight into the relationship between nuclear mechanics and stem cell differentiation, which may guide clinical applications in the future.
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9
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Hanson L, Zhao W, Lou HY, Lin ZC, Lee SW, Chowdary P, Cui Y, Cui B. Vertical nanopillars for in situ probing of nuclear mechanics in adherent cells. NATURE NANOTECHNOLOGY 2015; 10:554-62. [PMID: 25984833 PMCID: PMC5108456 DOI: 10.1038/nnano.2015.88] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 03/09/2015] [Indexed: 04/14/2023]
Abstract
The mechanical stability and deformability of the cell nucleus are crucial to many biological processes, including migration, proliferation and polarization. In vivo, the cell nucleus is frequently subjected to deformation on a variety of length and time scales, but current techniques for studying nuclear mechanics do not provide access to subnuclear deformation in live functioning cells. Here we introduce arrays of vertical nanopillars as a new method for the in situ study of nuclear deformability and the mechanical coupling between the cell membrane and the nucleus in live cells. Our measurements show that nanopillar-induced nuclear deformation is determined by nuclear stiffness, as well as opposing effects from actin and intermediate filaments. Furthermore, the depth, width and curvature of nuclear deformation can be controlled by varying the geometry of the nanopillar array. Overall, vertical nanopillar arrays constitute a novel approach for non-invasive, subcellular perturbation of nuclear mechanics and mechanotransduction in live cells.
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Affiliation(s)
- Lindsey Hanson
- Department of Chemistry, 333 Campus Drive, Stanford, California 94305, USA
| | - Wenting Zhao
- Department of Materials Science and Engineering, 496 Lomita Mall, Stanford, California 94305, USA
| | - Hsin-Ya Lou
- Department of Chemistry, 333 Campus Drive, Stanford, California 94305, USA
| | - Ziliang Carter Lin
- Department of Applied Physics, 348 Via Pueblo, Stanford University, Stanford, California 94305, USA
| | - Seok Woo Lee
- Department of Materials Science and Engineering, 496 Lomita Mall, Stanford, California 94305, USA
| | - Praveen Chowdary
- Department of Chemistry, 333 Campus Drive, Stanford, California 94305, USA
| | - Yi Cui
- Department of Materials Science and Engineering, 496 Lomita Mall, Stanford, California 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- ;
| | - Bianxiao Cui
- Department of Chemistry, 333 Campus Drive, Stanford, California 94305, USA
- ;
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10
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Ankam S, Lim CK, Yim EK. Actomyosin contractility plays a role in MAP2 expression during nanotopography-directed neuronal differentiation of human embryonic stem cells. Biomaterials 2015; 47:20-8. [DOI: 10.1016/j.biomaterials.2015.01.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 12/31/2014] [Accepted: 01/12/2015] [Indexed: 01/10/2023]
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11
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Jones D, Park D, Anghelina M, Pécot T, Machiraju R, Xue R, Lannutti JJ, Thomas J, Cole SL, Moldovan L, Moldovan NI. Actin grips: circular actin-rich cytoskeletal structures that mediate the wrapping of polymeric microfibers by endothelial cells. Biomaterials 2015; 52:395-406. [PMID: 25818446 PMCID: PMC4418805 DOI: 10.1016/j.biomaterials.2015.02.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 02/03/2015] [Indexed: 01/13/2023]
Abstract
Interaction of endothelial-lineage cells with three-dimensional substrates was much less studied than that with flat culture surfaces. We investigated the in vitro attachment of both mature endothelial cells (ECs) and of less differentiated EC colony-forming cells to poly-ε-capro-lactone (PCL) fibers with diameters in 5-20 μm range ('scaffold microfibers', SMFs). We found that notwithstanding the poor intrinsic adhesiveness to PCL, both cell types completely wrapped the SMFs after long-term cultivation, thus attaining a cylindrical morphology. In this system, both EC types grew vigorously for more than a week and became increasingly more differentiated, as shown by multiplexed gene expression. Three-dimensional reconstructions from multiphoton confocal microscopy images using custom software showed that the filamentous (F) actin bundles took a conspicuous ring-like organization around the SMFs. Unlike the classical F-actin-containing stress fibers, these rings were not associated with either focal adhesions or intermediate filaments. We also demonstrated that plasma membrane boundaries adjacent to these circular cytoskeletal structures were tightly yet dynamically apposed to the SMFs, for which reason we suggest to call them 'actin grips'. In conclusion, we describe a particular form of F-actin assembly with relevance for cytoskeletal organization in response to biomaterials, for endothelial-specific cell behavior in vitro and in vivo, and for tissue engineering.
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Affiliation(s)
- Desiree Jones
- Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - DoYoung Park
- Department of Computer Sciences and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Mirela Anghelina
- Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Thierry Pécot
- Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA; Department of Computer Sciences and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Raghu Machiraju
- Department of Computer Sciences and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Ruipeng Xue
- Department of Materials Sciences, The Ohio State University, Columbus, OH, 43210, USA
| | - John J Lannutti
- Department of Materials Sciences, The Ohio State University, Columbus, OH, 43210, USA
| | - Jessica Thomas
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Sara L Cole
- Campus Microscopy and Imaging Facility, The Ohio State University, Columbus, OH, 43210, USA
| | - Leni Moldovan
- Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Nicanor I Moldovan
- Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA.
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12
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Nuclear deformability constitutes a rate-limiting step during cell migration in 3-D environments. Cell Mol Bioeng 2014; 7:293-306. [PMID: 25436017 DOI: 10.1007/s12195-014-0342-y] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Cell motility plays a critical role in many physiological and pathological settings, ranging from wound healing to cancer metastasis. While cell migration on 2-dimensional (2-D) substrates has been studied for decades, the physical challenges cells face when moving in 3-D environments are only now emerging. In particular, the cell nucleus, which occupies a large fraction of the cell volume and is normally substantially stiffer than the surrounding cytoplasm, may impose a major obstacle when cells encounter narrow constrictions in the interstitial space, the extracellular matrix, or small capillaries. Using novel microfluidic devices that allow observation of cells moving through precisely defined geometries at high spatial and temporal resolution, we determined nuclear deformability as a critical factor in the cells' ability to pass through constrictions smaller than the size of the nucleus. Furthermore, we found that cells with reduced levels of the nuclear envelope proteins lamins A/C, which are the main determinants of nuclear stiffness, passed significantly faster through narrow constrictions during active migration and passive perfusion. Given recent reports that many human cancers have altered lamin expression, our findings suggest a novel biophysical mechanism by which changes in nuclear structure and composition may promote cancer cell invasion and metastasis.
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13
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Shin JW, Swift J, Ivanovska I, Spinler KR, Buxboim A, Discher DE. Mechanobiology of bone marrow stem cells: from myosin-II forces to compliance of matrix and nucleus in cell forms and fates. Differentiation 2013; 86:77-86. [PMID: 23790394 PMCID: PMC3964600 DOI: 10.1016/j.diff.2013.05.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 05/01/2013] [Accepted: 05/02/2013] [Indexed: 12/22/2022]
Abstract
Adult stem cells and progenitors are of great interest for their clinical application as well as their potential to reveal deep sensitivities to microenvironmental factors. The bone marrow is a niche for at least two types of stem cells, and the prototype is the hematopoietic stem cell/progenitors (HSC/Ps), which have saved many thousands of patients for several decades now. In bone marrow, HSC/Ps interact functionally with marrow stromal cells that are often referred to as mesenchymal stem cells (MSCs) or derivatives thereof. Myosin and matrix elasticity greatly affect MSC function, and these mechanobiological factors are now being explored with HSC/Ps both in vitro and in vivo. Also emerging is a role for the nucleus as a mechanically sensitive organelle that is semi-permeable to transcription factors which are modified for nuclear entry by cytoplasmic mechanobiological pathways. Since therapies envisioned with induced pluripotent stem cells and embryonic stem cells generally involve in vitro commitment to an adult stem cell or progenitor, a very deep understanding of stem cell mechanobiology is essential to progress with these multi-potent cells.
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Affiliation(s)
- Jae-Won Shin
- Molecular and Cell Biophysics Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
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