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Melcher ML, Block I, Kropf K, Singh AK, Posern G. Interplay of the transcription factor MRTF-A and matrix stiffness controls mammary acinar structure and protrusion formation. Cell Commun Signal 2022; 20:158. [PMID: 36229824 PMCID: PMC9563482 DOI: 10.1186/s12964-022-00977-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 09/18/2022] [Indexed: 11/12/2022] Open
Abstract
Background Ongoing differentiation processes characterize the mammary gland during sexual development and reproduction. In contrast, defective remodelling is assumed to be causal for breast tumorigenesis. We have shown recently that the myocardin-related transcription factor A (MRTF-A) is essential for forming regular hollow acinar structures. Moreover, MRTF-A activity is known to depend on the biochemical and physical properties of the surrounding extracellular matrix. In this study we analysed the mutual interaction of different matrix stiffnesses and MRTF-A activities on formation and maintenance of mammary acini. Methods Human MCF10A acini and primary mature organoids isolated from murine mammary glands were cultivated in 3D on soft and stiff matrices (200–4000 Pa) in conjunction with the Rho/MRTF/SRF pathway inhibitor CCG-203971 and genetic activation of MRTF-A. Results Three-dimensional growth on stiff collagen matrices (> 3000 Pa) was accompanied by increased MRTF-A activity and formation of invasive protrusions in acini cultures of human mammary MCF10A cells. Differential coating and synthetic hydrogels indicated that protrusion formation was attributable to stiffness but not the biochemical constitution of the matrix. Stiffness-induced protrusion formation was also observed in preformed acini isolated from murine mammary glands. Acinar outgrowth in both the MCF10A acini and the primary organoids was partially reverted by treatment with the Rho/MRTF/SRF pathway inhibitor CCG-203971. However, genetic activation of MRTF-A in the mature primary acini also reduced protrusion formation on stiff matrices, whilst it strongly promoted luminal filling matrix-independently. Conclusion Our results suggest an intricate crosstalk between matrix stiffness and MRTF-A, whose activity is required for protrusion formation and sufficient for luminal filling of mammary acini. Video Abstract
Supplementary Information The online version contains supplementary material available at 10.1186/s12964-022-00977-2. Formation of mammary acini depends on crosstalk between matrix stiffness and MRTF-A
Increased matrix stiffness elevates MRTF-A activity and protrusion formation Protrusion formation of MCF10A-derived and primary murine acini is MRTF-dependent
Genetic MRTF-A activation in primary organoids is sufficient for luminal filling
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Affiliation(s)
- Marie-Luise Melcher
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114, Halle (Saale), Germany
| | - Ines Block
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114, Halle (Saale), Germany
| | - Karolin Kropf
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114, Halle (Saale), Germany
| | - Anurag Kumar Singh
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114, Halle (Saale), Germany
| | - Guido Posern
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, 06114, Halle (Saale), Germany.
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2
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An R. MRTF may be the missing link in a multiscale mechanobiology approach toward macrophage dysfunction in space. Front Cell Dev Biol 2022; 10:997365. [PMID: 36172272 PMCID: PMC9510870 DOI: 10.3389/fcell.2022.997365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/10/2022] [Indexed: 11/23/2022] Open
Abstract
Macrophages exhibit impaired phagocytosis, adhesion, migration, and cytokine production in space, hindering their ability to elicit immune responses. Considering that the combined effect of spaceflight microgravity and radiation is multiscale and multifactorial in nature, it is expected that contradictory findings are common in the field. This theory paper reanalyzes research on the macrophage spaceflight response across multiple timescales from seconds to weeks, and spatial scales from the molecular, intracellular, extracellular, to the physiological. Key findings include time-dependence of both pro-inflammatory activation and integrin expression. Here, we introduce the time-dependent, intracellular localization of MRTF-A as a hypothetical confounder of macrophage activation. We discuss the mechanosensitive MRTF-A/SRF pathway dependence on the actin cytoskeleton/nucleoskeleton, microtubules, membrane mechanoreceptors, hypoxia, oxidative stress, and intracellular/extracellular crosstalk. By adopting a multiscale perspective, this paper provides the first mechanistic answer for a three-decade-old question regarding impaired cytokine secretion in microgravity—and strengthens the connection between the recent advances in mechanobiology, microgravity, and the spaceflight immune response. Finally, we hypothesize MRTF involvement and complications in treating spaceflight-induced cardiovascular, skeletal, and immune disease.
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Affiliation(s)
- Rocky An
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, United States
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States
- *Correspondence: Rocky An,
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3
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Microfabricated Stretching Devices for Studying the Effects of Tensile Stress on Cells and Tissues. BIOCHIP JOURNAL 2022. [DOI: 10.1007/s13206-022-00073-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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4
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Kuchler O, Gerlach J, Vomhof T, Hettich J, Steinmetz J, Gebhardt JCM, Michaelis J, Knöll B. Single-molecule tracking (SMT) and localization of SRF and MRTF transcription factors during neuronal stimulation and differentiation. Open Biol 2022; 12:210383. [PMID: 35537478 PMCID: PMC9090491 DOI: 10.1098/rsob.210383] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In cells, proteins encoded by the same gene do not all behave uniformly but engage in functional subpopulations induced by spatial or temporal segregation. While conventional microscopy has limitations in revealing such spatial and temporal diversity, single-molecule tracking (SMT) microscopy circumvented this problem and allows for high-resolution imaging and quantification of dynamic single-molecule properties. Particularly in the nucleus, SMT has identified specific DNA residence times of transcription factors (TFs), DNA-bound TF fractions and positions of transcriptional hot-spots upon cell stimulation. By contrast to cell stimulation, SMT has not been employed to follow dynamic TF changes along stages of cell differentiation. Herein, we analysed the serum response factor (SRF), a TF involved in the differentiation of many cell types to study nuclear single-molecule dynamics in neuronal differentiation. Our data in living mouse hippocampal neurons show dynamic changes in SRF DNA residence time and SRF DNA-bound fraction between the stages of adhesion, neurite growth and neurite differentiation in axon and dendrites. Using TALM (tracking and localization microscopy), we identified nuclear positions of SRF clusters and observed changes in their numbers and size during differentiation. Furthermore, we show that the SRF cofactor MRTF-A (myocardin-related TF or MKL1) responds to cell activation by enhancing the long-bound DNA fraction. Finally, a first SMT colocalization study of two proteins was performed in living cells showing enhanced SRF/MRTF-A colocalization upon stimulation. In summary, SMT revealed modulation of dynamic TF properties during cell stimulation and differentiation.
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Affiliation(s)
- Oliver Kuchler
- Institute of Neurobiochemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany,Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Jule Gerlach
- Institute of Neurobiochemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany,Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Thomas Vomhof
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Johannes Hettich
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Julia Steinmetz
- Department of Statistics, TU Dortmund University, August-Schmidt Straße 1, 44227 Dortmund, Germany
| | | | - Jens Michaelis
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Bernd Knöll
- Institute of Neurobiochemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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5
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Echarri A. A Multisensory Network Drives Nuclear Mechanoadaptation. Biomolecules 2022; 12:biom12030404. [PMID: 35327596 PMCID: PMC8945967 DOI: 10.3390/biom12030404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/24/2022] [Accepted: 02/26/2022] [Indexed: 12/03/2022] Open
Abstract
Cells have adapted to mechanical forces early in evolution and have developed multiple mechanisms ensuring sensing of, and adaptation to, the diversity of forces operating outside and within organisms. The nucleus must necessarily adapt to all types of mechanical signals, as its functions are essential for virtually all cell processes, many of which are tuned by mechanical cues. To sense forces, the nucleus is physically connected with the cytoskeleton, which senses and transmits forces generated outside and inside the cell. The nuclear LINC complex bridges the cytoskeleton and the nuclear lamina to transmit mechanical information up to the chromatin. This system creates a force-sensing macromolecular complex that, however, is not sufficient to regulate all nuclear mechanoadaptation processes. Within the nucleus, additional mechanosensitive structures, including the nuclear envelope and the nuclear pore complex, function to regulate nuclear mechanoadaptation. Similarly, extra nuclear mechanosensitive systems based on plasma membrane dynamics, mechanotransduce information to the nucleus. Thus, the nucleus has the intrinsic structural components needed to receive and interpret mechanical inputs, but also rely on extra nuclear mechano-sensors that activate nuclear regulators in response to force. Thus, a network of mechanosensitive cell structures ensures that the nucleus has a tunable response to mechanical cues.
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Affiliation(s)
- Asier Echarri
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Mechanoadaptation and Caveolae Biology Laboratory, Areas of Cell & Developmental Biology, Calle Melchor Fernández Almagro, 3, 28029 Madrid, Spain
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6
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Heib T, Hermanns HM, Manukjan G, Englert M, Kusch C, Becker IC, Gerber A, Wackerbarth LM, Burkard P, Dandekar T, Balkenhol J, Jahn D, Beck S, Meub M, Dütting S, Stigloher C, Sauer M, Cherpokova D, Schulze H, Brakebusch C, Nieswandt B, Nagy Z, Pleines I. RhoA/Cdc42 signaling drives cytoplasmic maturation but not endomitosis in megakaryocytes. Cell Rep 2021; 35:109102. [PMID: 33979620 DOI: 10.1016/j.celrep.2021.109102] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 02/20/2021] [Accepted: 04/18/2021] [Indexed: 12/15/2022] Open
Abstract
Megakaryocytes (MKs), the precursors of blood platelets, are large, polyploid cells residing mainly in the bone marrow. We have previously shown that balanced signaling of the Rho GTPases RhoA and Cdc42 is critical for correct MK localization at bone marrow sinusoids in vivo. Using conditional RhoA/Cdc42 double-knockout (DKO) mice, we reveal here that RhoA/Cdc42 signaling is dispensable for the process of polyploidization in MKs but essential for cytoplasmic MK maturation. Proplatelet formation is virtually abrogated in the absence of RhoA/Cdc42 and leads to severe macrothrombocytopenia in DKO animals. The MK maturation defect is associated with downregulation of myosin light chain 2 (MLC2) and β1-tubulin, as well as an upregulation of LIM kinase 1 and cofilin-1 at both the mRNA and protein level and can be linked to impaired MKL1/SRF signaling. Our findings demonstrate that MK endomitosis and cytoplasmic maturation are separately regulated processes, and the latter is critically controlled by RhoA/Cdc42.
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Affiliation(s)
- Tobias Heib
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Heike M Hermanns
- Department of Internal Medicine II, Hepatology Research Laboratory, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Georgi Manukjan
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Maximilian Englert
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Charly Kusch
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Isabelle Carlotta Becker
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Annika Gerber
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Lou Martha Wackerbarth
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Philipp Burkard
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Thomas Dandekar
- Department of Bioinformatics, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Johannes Balkenhol
- Department of Internal Medicine II, Hepatology Research Laboratory, University Hospital Würzburg, 97080 Würzburg, Germany; Department of Bioinformatics, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Daniel Jahn
- Department of Internal Medicine II, Hepatology Research Laboratory, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Sarah Beck
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Mara Meub
- Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Sebastian Dütting
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Christian Stigloher
- Imaging Core Facility, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Deya Cherpokova
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Harald Schulze
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Cord Brakebusch
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, 2200 Copenhagen, Denmark
| | - Bernhard Nieswandt
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany.
| | - Zoltan Nagy
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany
| | - Irina Pleines
- Institute of Experimental Biomedicine, University Hospital, University of Würzburg, 97080 Würzburg, Germany; Rudolf Virchow Center, University of Würzburg, 97080 Würzburg, Germany.
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7
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Reed F, Larsuel ST, Mayday MY, Scanlon V, Krause DS. MRTFA: A critical protein in normal and malignant hematopoiesis and beyond. J Biol Chem 2021; 296:100543. [PMID: 33722605 PMCID: PMC8079280 DOI: 10.1016/j.jbc.2021.100543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 12/03/2022] Open
Abstract
Myocardin-related transcription factor A (MRTFA) is a coactivator of serum response factor, a transcription factor that participates in several critical cellular functions including cell growth and apoptosis. MRTFA couples transcriptional regulation to actin cytoskeleton dynamics, and the transcriptional targets of the MRTFA–serum response factor complex include genes encoding cytoskeletal proteins as well as immediate early genes. Previous work has shown that MRTFA promotes the differentiation of many cell types, including various types of muscle cells and hematopoietic cells, and MRTFA's interactions with other protein partners broaden its cellular roles. However, despite being first identified as part of the recurrent t(1;22) chromosomal translocation in acute megakaryoblastic leukemia, the mechanisms by which MRTFA functions in malignant hematopoiesis have yet to be defined. In this review, we provide an in-depth examination of the structure, regulation, and known functions of MRTFA with a focus on hematopoiesis. We conclude by identifying areas of study that merit further investigation.
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Affiliation(s)
- Fiona Reed
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA; Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut, USA
| | - Shannon T Larsuel
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA; Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut, USA
| | - Madeline Y Mayday
- Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut, USA; Department of Pathology, Yale School of Medicine, New Haven, Connecticut, USA
| | - Vanessa Scanlon
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA; Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut, USA
| | - Diane S Krause
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA; Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut, USA; Department of Pathology, Yale School of Medicine, New Haven, Connecticut, USA.
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8
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Kepser LJ, Khudayberdiev S, Hinojosa LS, Macchi C, Ruscica M, Marcello E, Culmsee C, Grosse R, Rust MB. Cyclase-associated protein 2 (CAP2) controls MRTF-A localization and SRF activity in mouse embryonic fibroblasts. Sci Rep 2021; 11:4789. [PMID: 33637797 PMCID: PMC7910472 DOI: 10.1038/s41598-021-84213-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 02/12/2021] [Indexed: 01/09/2023] Open
Abstract
Recent studies identified cyclase-associated proteins (CAPs) as important regulators of actin dynamics that control assembly and disassembly of actin filaments (F-actin). While these studies significantly advanced our knowledge of their molecular functions, the physiological relevance of CAPs largely remained elusive. Gene targeting in mice implicated CAP2 in heart physiology and skeletal muscle development. Heart defects in CAP2 mutant mice were associated with altered activity of serum response factor (SRF), a transcription factor involved in multiple biological processes including heart function, but also skeletal muscle development. By exploiting mouse embryonic fibroblasts (MEFs) from CAP2 mutant mice, we aimed at deciphering the CAP2-dependent mechanism relevant for SRF activity. Reporter assays and mRNA quantification by qPCR revealed reduced SRF-dependent gene expression in mutant MEFs. Reduced SRF activity in CAP2 mutant MEFs was associated with altered actin turnover, a shift in the actin equilibrium towards monomeric actin (G-actin) as well as and reduced nuclear levels of myocardin-related transcription factor A (MRTF-A), a transcriptional SRF coactivator that is shuttled out of the nucleus and, hence, inhibited upon G-actin binding. Moreover, pharmacological actin manipulation with jasplakinolide restored MRTF-A distribution in mutant MEFs. Our data are in line with a model in which CAP2 controls the MRTF-SRF pathway in an actin-dependent manner. While MRTF-A localization and SRF activity was impaired under basal conditions, serum stimulation induced nuclear MRTF-A translocation and SRF activity in mutant MEFs similar to controls. In summary, our data revealed that in MEFs CAP2 controls basal MRTF-A localization and SRF activity, while it was dispensable for serum-induced nuclear MRTF-A translocation and SRF stimulation.
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Affiliation(s)
- Lara-Jane Kepser
- Institute of Physiological Chemistry, Philipps-University of Marburg, 35032, Marburg, Germany
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany
| | - Sharof Khudayberdiev
- Institute of Physiological Chemistry, Philipps-University of Marburg, 35032, Marburg, Germany
| | - Laura Soto Hinojosa
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany
- Institute of Pharmacology, University of Marburg, 35032, Marburg, Germany
| | - Chiara Macchi
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133, Milan, Italy
| | - Massimiliano Ruscica
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133, Milan, Italy
| | - Elena Marcello
- Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133, Milan, Italy
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, University of Marburg, 35032, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032, Marburg, Germany
| | - Robert Grosse
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany
- Institute of Pharmacology, University of Marburg, 35032, Marburg, Germany
| | - Marco B Rust
- Institute of Physiological Chemistry, Philipps-University of Marburg, 35032, Marburg, Germany.
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany.
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032, Marburg, Germany.
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9
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Montagner M, Dupont S. Mechanical Forces as Determinants of Disseminated Metastatic Cell Fate. Cells 2020; 9:E250. [PMID: 31963820 PMCID: PMC7016729 DOI: 10.3390/cells9010250] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/01/2020] [Accepted: 01/04/2020] [Indexed: 12/19/2022] Open
Abstract
Disseminated metastatic cancer cells represent one of the most relevant causes of disease relapse and associated death for cancer patients, and a therapeutic target of the highest priority. Still, our understanding of how disseminated cancer cells survive in the foreign metastatic environment, and eventually cause metastatic outgrowth, remains rather limited. In this review we focus on the cell microenvironment as a key regulator of cell behavior at the metastatic site, and especially on the mechanical properties of the extracellular matrix and associated integrin signaling. We discuss available evidence pointing to a pervasive role of extracellular matrix (ECM) mechanical properties in regulating cancer cell proliferation and survival after dissemination, and propose that this might represent an important bottleneck for cells invading and establishing into a novel tissue. We point to the known molecular players, how these might contribute to modulate the mechanical properties of the metastatic environment, and the response of cells to these cues. Finally, we propose that emerging knowledge on the physical interaction of disseminated metastatic cells and on the downstream mechanotransduction pathways, including YAP/TAZ (Yes-associated protein-1 and WW-domain transcription activator 1) and MRTFs (Myocardin-related transcription factors), may help to identify novel approaches for therapy.
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Affiliation(s)
- Marco Montagner
- Department of Molecular Medicine, University of Padua, via Bassi 58/B, zip 35121 Padua, Italy
| | - Sirio Dupont
- Department of Molecular Medicine, University of Padua, via Bassi 58/B, zip 35121 Padua, Italy
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Meli VS, Veerasubramanian PK, Atcha H, Reitz Z, Downing TL, Liu WF. Biophysical regulation of macrophages in health and disease. J Leukoc Biol 2019; 106:283-299. [PMID: 30861205 PMCID: PMC7001617 DOI: 10.1002/jlb.mr0318-126r] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Macrophages perform critical functions for homeostasis and immune defense in tissues throughout the body. These innate immune cells are capable of recognizing and clearing dead cells and pathogens, and orchestrating inflammatory and healing processes that occur in response to injury. In addition, macrophages are involved in the progression of many inflammatory diseases including cardiovascular disease, fibrosis, and cancer. Although it has long been known that macrophages respond dynamically to biochemical signals in their microenvironment, the role of biophysical cues has only recently emerged. Furthermore, many diseases that involve macrophages are also characterized by changes to the tissue biophysical environment. This review will discuss current knowledge about the effects of biophysical cues including matrix stiffness, material topography, and applied mechanical forces, on macrophage behavior. We will also describe the role of molecules that are known to be important for mechanotransduction, including adhesion molecules, ion channels, as well as nuclear mediators such as transcription factors, scaffolding proteins, and epigenetic regulators. Together, this review will illustrate a developing role of biophysical cues in macrophage biology, and also speculate upon molecular targets that may potentially be exploited therapeutically to treat disease.
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Affiliation(s)
- Vijaykumar S. Meli
- Department of Biomedical Engineering, University of California Irvine, CA 92697
- The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California Irvine, CA 92697
| | - Praveen K. Veerasubramanian
- Department of Biomedical Engineering, University of California Irvine, CA 92697
- The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California Irvine, CA 92697
| | - Hamza Atcha
- Department of Biomedical Engineering, University of California Irvine, CA 92697
- The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California Irvine, CA 92697
| | - Zachary Reitz
- Department of Biomedical Engineering, University of California Irvine, CA 92697
- The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California Irvine, CA 92697
| | - Timothy L. Downing
- Department of Biomedical Engineering, University of California Irvine, CA 92697
- The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California Irvine, CA 92697
- Department of Microbiology and Molecular Genetics, University of California Irvine, CA 92697
| | - Wendy F. Liu
- Department of Biomedical Engineering, University of California Irvine, CA 92697
- The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California Irvine, CA 92697
- Department of Chemical and Biomolecular Engineering, University of California Irvine, CA 92697
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Sidorenko E, Vartiainen MK. Nucleoskeletal regulation of transcription: Actin on MRTF. Exp Biol Med (Maywood) 2019; 244:1372-1381. [PMID: 31142145 DOI: 10.1177/1535370219854669] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Myocardin-related transcription factor A (MRTF-A) and serum response factor (SRF) form an essential transcriptional complex that regulates the expression of many cytoskeletal genes in response to dynamic changes in the actin cytoskeleton. The nucleoskeleton, a “dynamic network of networks,” consists of numerous proteins that contribute to nuclear shape and to its various functions, including gene expression. In this review, we will discuss recent work that has identified many nucleoskeletal proteins, such as nuclear lamina and lamina-associated proteins, nuclear actin, and the linker of the cytoskeleton and nucleoskeleton complex as important regulators of MRTF-A/SRF transcriptional activity, especially in the context of mechanical control of transcription. Impact statement Regulation of gene expression is a fundamental cellular process that ensures the appropriate response of a cell to its surroundings. Alongside biochemical signals, mechanical cues, such as substrate rigidity, have been recognized as key regulators of gene expression. Nucleoskeletal components play an important role in mechanoresponsive transcription, particularly in controlling the activity of MRTF-A/SRF transcription factors. This ensures that the cell can balance the internal and external mechanical forces by fine-tuning the expression of cytoskeletal genes.
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Affiliation(s)
- Ekaterina Sidorenko
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
| | - Maria K Vartiainen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
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12
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Kant S, Freytag B, Herzog A, Reich A, Merkel R, Hoffmann B, Krusche CA, Leube RE. Desmoglein 2 mutation provokes skeletal muscle actin expression and accumulation at intercalated discs in murine hearts. J Cell Sci 2019; 132:jcs.199612. [PMID: 30659114 DOI: 10.1242/jcs.199612] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 12/30/2018] [Indexed: 01/05/2023] Open
Abstract
Arrhythmogenic cardiomyopathy (AC) is an incurable progressive disease that is linked to mutations in genes coding for components of desmosomal adhesions that are localized to the intercalated disc region, which electromechanically couples adjacent cardiomyocytes. To date, the underlying molecular dysfunctions are not well characterized. In two murine AC models, we find an upregulation of the skeletal muscle actin gene (Acta1), which is known to be a compensatory reaction to compromised heart function. Expression of this gene is elevated prior to visible morphological alterations and clinical symptoms, and persists throughout pathogenesis with an additional major rise during the chronic disease stage. We provide evidence that the increased Acta1 transcription is initiated through nuclear activation of the serum response transcription factor (SRF) by its transcriptional co-activator megakaryoblastic leukemia 1 protein (MKL1, also known as MRTFA). Our data further suggest that perturbed desmosomal adhesion causes Acta1 overexpression during the early stages of the disease, which is amplified by transforming growth factor β (TGFβ) release from fibrotic lesions and surrounding cardiomyocytes during later disease stages. These observations highlight a hitherto unknown molecular AC pathomechanism.
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Affiliation(s)
- Sebastian Kant
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Benjamin Freytag
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Antonia Herzog
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Anna Reich
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Rudolf Merkel
- Forschungszentrum Jülich, Institute of Complex Systems, ICS-7, Biomechanics, 52428 Jülich, Germany
| | - Bernd Hoffmann
- Forschungszentrum Jülich, Institute of Complex Systems, ICS-7, Biomechanics, 52428 Jülich, Germany
| | - Claudia A Krusche
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
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13
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Kassianidou E, Kalita J, Lim RYH. The role of nucleocytoplasmic transport in mechanotransduction. Exp Cell Res 2019; 377:86-93. [PMID: 30768931 DOI: 10.1016/j.yexcr.2019.02.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/10/2019] [Accepted: 02/12/2019] [Indexed: 12/12/2022]
Abstract
Cells integrate mechanical and biochemical signals via a process called mechanotransduction to generate essential gene expression patterns in space and time. This is vital for cell migration and proliferation as well as tissue morphogenesis and remodeling. While the force-sensing and force-transducing mechanisms are generally known, it remains unclear how mechanoresponsive transcription factors (TFs) are selectively translocated into the nucleus upon force activation. Such TFs include Yes-Associated Protein (YAP), Myocardin Related Transcription Factors (MRTFs), Hypoxia Induced Factors (HIFs) and others. Here, we discuss how the nucleocytoplasmic transport machinery intersects with mechanoresponsive TFs to facilitate their selective transport through nuclear pore complexes.
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Affiliation(s)
- Elena Kassianidou
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - Joanna Kalita
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - Roderick Y H Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
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14
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Persistent inhibition of pore-based cell migration by sub-toxic doses of miuraenamide, an actin filament stabilizer. Sci Rep 2017; 7:16407. [PMID: 29180826 PMCID: PMC5703899 DOI: 10.1038/s41598-017-16759-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 11/16/2017] [Indexed: 12/30/2022] Open
Abstract
Opposed to tubulin-binding agents, actin-binding small molecules have not yet become part of clinical tumor treatment, most likely due to the fear of general cytotoxicity. Addressing this problem, we investigated the long-term efficacy of sub-toxic doses of miuraenamide, an actin filament stabilizing natural compound, on tumor cell (SKOV3) migration. No cytotoxic effects or persistent morphological changes occurred at a concentration of miuraenamide of 20 nM. After 72 h treatment with this concentration, nuclear stiffness was increased, causing reduced migration through pores in a Boyden chamber, while cell migration and chemotaxis per se were unaltered. A concomitant time-resolved proteomic approach showed down regulation of a protein cluster after 56 h treatment. This cluster correlated best with the Wnt signaling pathway. A further analysis of the actin associated MRTF/SRF signaling showed a surprising reduction of SRF-regulated proteins. In contrast to acute effects of actin-binding compounds on actin at high concentrations, long-term low-dose treatment elicits much more subtle but still functionally relevant changes beyond simple destruction of the cytoskeleton. These range from biophysical parameters to regulation of protein expression, and may help to better understand the complex biology of actin, as well as to initiate alternative regimes for the testing of actin-targeting drugs.
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15
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Tatapudy S, Aloisio F, Barber D, Nystul T. Cell fate decisions: emerging roles for metabolic signals and cell morphology. EMBO Rep 2017; 18:2105-2118. [PMID: 29158350 DOI: 10.15252/embr.201744816] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 09/14/2017] [Accepted: 10/24/2017] [Indexed: 12/25/2022] Open
Abstract
Understanding how cell fate decisions are regulated is a fundamental goal of developmental and stem cell biology. Most studies on the control of cell fate decisions address the contributions of changes in transcriptional programming, epigenetic modifications, and biochemical differentiation cues. However, recent studies have found that other aspects of cell biology also make important contributions to regulating cell fate decisions. These cues can have a permissive or instructive role and are integrated into the larger network of signaling, functioning both upstream and downstream of developmental signaling pathways. Here, we summarize recent insights into how cell fate decisions are influenced by four aspects of cell biology: metabolism, reactive oxygen species (ROS), intracellular pH (pHi), and cell morphology. For each topic, we discuss how these cell biological cues interact with each other and with protein-based mechanisms for changing gene transcription. In addition, we highlight several questions that remain unanswered in these exciting and relatively new areas of the field.
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Affiliation(s)
- Sumitra Tatapudy
- Departments of Anatomy and OB-GYN/RS, University of California, San Francisco, San Francisco, CA, USA
| | - Francesca Aloisio
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
| | - Diane Barber
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
| | - Todd Nystul
- Departments of Anatomy and OB-GYN/RS, University of California, San Francisco, San Francisco, CA, USA
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16
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Mechanosensing in liver regeneration. Semin Cell Dev Biol 2017; 71:153-167. [DOI: 10.1016/j.semcdb.2017.07.041] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/25/2017] [Accepted: 07/26/2017] [Indexed: 12/13/2022]
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17
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Willer MK, Carroll CW. Substrate stiffness-dependent regulation of the SRF-Mkl1 co-activator complex requires the inner nuclear membrane protein Emerin. J Cell Sci 2017; 130:2111-2118. [PMID: 28576971 DOI: 10.1242/jcs.197517] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 05/13/2017] [Indexed: 01/05/2023] Open
Abstract
The complex comprising serum response factor (SRF) and megakaryoblastic leukemia 1 protein (Mkl1) promotes myofibroblast differentiation during wound healing. SRF-Mkl1 is sensitive to the mechanical properties of the extracellular environment; but how cells sense and transduce mechanical cues to modulate SRF-Mkl1-dependent gene expression is not well understood. Here, we demonstrate that the nuclear lamina-associated inner nuclear membrane protein Emerin stimulates SRF-Mkl1-dependent gene activity in a substrate stiffness-dependent manner. Specifically, Emerin was required for Mkl1 nuclear accumulation and maximal SRF-Mkl1-dependent gene expression in response to serum stimulation of cells grown on stiff substrates but was dispensable on more compliant substrates. Focal adhesion area was also reduced in cells lacking Emerin, consistent with a role for Emerin in sensing substrate stiffness. Expression of a constitutively active form of Mkl1 bypassed the requirement for Emerin in SRF-Mkl1-dependent gene expression and reversed the focal adhesion defects evident in EmdKO fibroblasts. Together, these data indicate that Emerin, a conserved nuclear lamina protein, couples extracellular matrix mechanics and SRF-Mkl1-dependent transcription.
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Affiliation(s)
- Margaret K Willer
- Dept. Of Cell Biology, Yale School of Medicine, New Haven, CT 06520, USA
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18
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Li N, Yuan Q, Cao XL, Zhang Y, Min ZL, Xu SQ, Yu ZJ, Cheng J, Zhang C, Hu XM. Opposite effects of HDAC5 and p300 on MRTF-A-related neuronal apoptosis during ischemia/reperfusion injury in rats. Cell Death Dis 2017; 8:e2624. [PMID: 28230854 PMCID: PMC5386465 DOI: 10.1038/cddis.2017.16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 12/23/2016] [Accepted: 12/28/2016] [Indexed: 01/22/2023]
Abstract
Our recent study has revealed that the myocardin-related transcription factor-A (MRTF-A) is involved in the apoptosis of cortical neurons induced by ischemia/reperfusion (I/R). Histone deacetylase 5 (HDAC5) and histone acetyltransferase p300 (P300) are two well-known regulators for transcription factors; however, their roles in MRTF-A-related effect on neuronal injuries during I/R are still unclear. In this study, in a model rat cerebral I/R injury via middle cerebral artery occlusion and reperfusion, we found that the expression and activity of HDAC5 was upregulated, whereas p300 and MRTF-A were downregulated both in expression and activity during I/R. Their expression changes and the interaction of the MRTF-A with HDAC5 or p300 were further verified by double immunofluorescence and co-immunoprecipitation. In cultured neuronal apoptosis model induced by H2O2, MRTF-A exhibited an anti-apoptotic effect by enhancing the transcription of Bcl-2 and Mcl-1 via CArG box binding. MRTF-A-induced anti-apoptotic effect was effectively inhibited by HDAC5, but was significantly enhanced by p300. The results suggest that both HDAC5 and p300 are involved in MRTF-A-mediated effect on neuronal apoptosis during ischemia/reperfusion injury, but with opposite effects.
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Affiliation(s)
- Na Li
- Department of Pharmacy, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.,Drug Research Base of Cardiovascular and Cerebral Vascular, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Qiong Yuan
- Department of Pharmacy, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.,Drug Research Base of Cardiovascular and Cerebral Vascular, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Xiao-Lu Cao
- Department of Pharmacy, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.,Drug Research Base of Cardiovascular and Cerebral Vascular, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Ying Zhang
- Department of Pharmacy, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.,Drug Research Base of Cardiovascular and Cerebral Vascular, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Zhen-Li Min
- Department of Pharmacy, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.,Drug Research Base of Cardiovascular and Cerebral Vascular, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Shi-Qiang Xu
- Department of Pharmacy, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.,Drug Research Base of Cardiovascular and Cerebral Vascular, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Zhi-Jun Yu
- Department of Pharmacy, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.,Drug Research Base of Cardiovascular and Cerebral Vascular, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Jing Cheng
- Department of Pharmacy, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.,Drug Research Base of Cardiovascular and Cerebral Vascular, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Chunxiang Zhang
- Department of Pharmacy, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.,Drug Research Base of Cardiovascular and Cerebral Vascular, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.,Department of Biomedical Engineering, School of Medicine and School of Engineering, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Xia-Min Hu
- Department of Pharmacy, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.,Drug Research Base of Cardiovascular and Cerebral Vascular, College of Medicine, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
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19
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Finch-Edmondson M, Sudol M. Framework to function: mechanosensitive regulators of gene transcription. Cell Mol Biol Lett 2016; 21:28. [PMID: 28536630 PMCID: PMC5415767 DOI: 10.1186/s11658-016-0028-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/16/2016] [Indexed: 01/06/2023] Open
Abstract
Mechanobiology has shifted our understanding of fundamental cellular and physiological functions. Changes to the stiffness of the extracellular matrix, cell rigidity, or shape of the cell environment were considered in the past to be a consequence of aging or pathological processes. We now understand that these factors can actually be causative biological mediators of cell growth to control organ size. Mechanical cues are known to trigger a relatively fast translocation of specific transcriptional co-factors such as MRTFs, YAP and TAZ from the cytoplasm to the cell nucleus to initiate discrete transcriptional programs. The focus of this review is the molecular mechanisms by which biophysical stimuli that induce changes in cytoplasmic actin dynamics are communicated within cells to elicit gene-specific transcription via nuclear localisation or activation of specialized transcription factors, namely MRTFs and the Hippo pathway effectors YAP and TAZ. We propose here that MRTFs, YAP and TAZ closely collaborate as mechano-effectors.
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Affiliation(s)
- Megan Finch-Edmondson
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, 117411 Singapore, Singapore.,Department of Physiology, National University of Singapore, Yong Loo Lin School of Medicine, 2 Medical Drive, 117597 Singapore, Singapore
| | - Marius Sudol
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, 117411 Singapore, Singapore.,Department of Physiology, National University of Singapore, Yong Loo Lin School of Medicine, 2 Medical Drive, 117597 Singapore, Singapore
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20
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Importance of environmental stiffness for megakaryocyte differentiation and proplatelet formation. Blood 2016; 128:2022-2032. [PMID: 27503502 DOI: 10.1182/blood-2016-02-699959] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 07/20/2016] [Indexed: 12/31/2022] Open
Abstract
Megakaryocyte (MK) differentiation occurs within the bone marrow (BM), a complex 3-dimensional (3D) environment of low stiffness exerting local external constraints. To evaluate the influence of the 3D mechanical constraints that MKs may encounter in vivo, we differentiated mouse BM progenitors in methylcellulose (MC) hydrogels tuned to mimic BM stiffness. We found that MKs grown in a medium of 30- to 60-Pa stiffness more closely resembled those in the BM in terms of demarcation membrane system (DMS) morphological aspect and exhibited higher ploidy levels, as compared with MKs in liquid culture. Following resuspension in a liquid medium, MC-grown MKs displayed twice as much proplatelet formation as cells grown in liquid culture. Thus, the MC gel, by mimicking external constraints, appeared to positively influence MK differentiation. To determine whether MKs adapt to extracellular stiffness through mechanotransduction involving actomyosin-based modulation of the intracellular tension, myosin-deficient (Myh9-/-) progenitors were grown in MC gels. Absence of myosin resulted in abnormal cell deformation and strongly decreased proplatelet formation, similarly to features observed for Myh9-/- MKs differentiated in situ but not in vitro. Moreover, megakaryoblastic leukemia 1 (MKL1), a well-known actor in mechanotransduction, was found to be preferentially relocated within the nucleus of MC-differentiated MKs, whereas its inhibition prevented MC-mediated increased proplatelet formation. Altogether, these data show that a 3D medium mimicking BM stiffness contributes, through the myosin IIA and MKL1 pathways, to a more favorable in vitro environment for MK differentiation, which ultimately translates into increased proplatelet production.
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21
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Introducing STRaNDs: shuttling transcriptional regulators that are non-DNA binding. Nat Rev Mol Cell Biol 2016; 17:523-32. [PMID: 27220640 DOI: 10.1038/nrm.2016.41] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Many proteins originally identified as cytoplasmic - including many associated with the cytoskeleton or cell junctions - are increasingly being found in the nucleus, where they have specific functions. Here, we focus on proteins that translocate from the cytoplasm to the nucleus in response to external signals and regulate transcription without binding to DNA directly (for example, through interaction with transcription factors). We propose that proteins with such characteristics are classified as a distinct group of extracellular signalling effectors, and we suggest the term STRaND (shuttling transcriptional regulators and non-DNA binding) to refer to this group. Crucial roles of STRaNDs include linking cell morphology and adhesion with changes in transcriptional programmes in response to signals such as mechanical stresses.
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22
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Mechanobiology of TGFβ signaling in the skeleton. Matrix Biol 2016; 52-54:413-425. [PMID: 26877077 DOI: 10.1016/j.matbio.2016.02.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/05/2016] [Accepted: 02/08/2016] [Indexed: 12/12/2022]
Abstract
Physical and biochemical cues play fundamental roles in the skeleton at both the tissue and cellular levels. The precise coordination of these cues is essential for skeletal development and homeostasis, and disruption of this coordination can drive disease progression. The growth factor TGFβ is involved in both the regulation of and cellular response to the physical microenvironment. It is essential to summarize the current findings regarding the mechanisms by which skeletal cells integrate physical and biochemical cues so that we can identify and address remaining gaps that could ultimately improve skeletal health. In this review, we describe the role of TGFβ in mechanobiological signaling in bone and cartilage at the tissue and cellular levels. We provide detail on how static and dynamic physical cues at the macro-level are transmitted to the micro-level, ultimately leading to regulation at each level of the TGFβ pathway and to cell differentiation. The continued integration of engineering and biological approaches is needed to answer many remaining questions, such as the mechanisms by which cells generate a coordinated response to physical and biochemical cues. We propose one such mechanism, through which the combination of TGFβ and an optimal physical microenvironment leads to synergistic induction of downstream TGFβ signaling.
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23
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Calvo F, Ranftl R, Hooper S, Farrugia AJ, Moeendarbary E, Bruckbauer A, Batista F, Charras G, Sahai E. Cdc42EP3/BORG2 and Septin Network Enables Mechano-transduction and the Emergence of Cancer-Associated Fibroblasts. Cell Rep 2015; 13:2699-714. [PMID: 26711338 PMCID: PMC4700053 DOI: 10.1016/j.celrep.2015.11.052] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 09/11/2015] [Accepted: 11/16/2015] [Indexed: 11/19/2022] Open
Abstract
Cancer-associated fibroblasts (CAFs) are non-cancerous cells found in solid tumors that remodel the tumor matrix and promote cancer invasion and angiogenesis. Here, we demonstrate that Cdc42EP3/BORG2 is required for the matrix remodeling, invasion, angiogenesis, and tumor-growth-promoting abilities of CAFs. Cdc42EP3 functions by coordinating the actin and septin networks. Furthermore, depletion of SEPT2 has similar effects to those of loss of Cdc42EP3, indicating a role for the septin network in the tumor stroma. Cdc42EP3 is upregulated early in fibroblast activation and precedes the emergence of the highly contractile phenotype characteristic of CAFs. Depletion of Cdc42EP3 in normal fibroblasts prevents their activation by cancer cells. We propose that Cdc42EP3 sensitizes fibroblasts to further cues-in particular, those activating actomyosin contractility-and thereby enables the generation of the pathological activated fibroblast state.
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Affiliation(s)
- Fernando Calvo
- Tumour Cell Biology Laboratory, Francis Crick Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK; Tumour Microenvironment Team, Division of Cancer Biology, Institute of Cancer Research, 237 Fulham Road, London SW2 6JB, UK.
| | - Romana Ranftl
- Tumour Microenvironment Team, Division of Cancer Biology, Institute of Cancer Research, 237 Fulham Road, London SW2 6JB, UK
| | - Steven Hooper
- Tumour Cell Biology Laboratory, Francis Crick Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Aaron J Farrugia
- Tumour Microenvironment Team, Division of Cancer Biology, Institute of Cancer Research, 237 Fulham Road, London SW2 6JB, UK
| | - Emad Moeendarbary
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Andreas Bruckbauer
- Lymphocyte Interaction Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Facundo Batista
- Lymphocyte Interaction Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Erik Sahai
- Tumour Cell Biology Laboratory, Francis Crick Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
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Abstract
Contrary to cytoplasmic actin structures, the biological functions of nuclear actin filaments remain largely enigmatic. Recent progress in the field, however, has determined nuclear actin structures in somatic cells either under steady state conditions or in response to extracellular signaling cues. These actin structures differ in size and shape as well as in their temporal appearance and dynamics. Thus, a picture emerges that suggests that mammalian cells may have different pathways and mechanisms to assemble nuclear actin filaments. Apart from serum- or LPA-triggered nuclear actin polymerization, integrin activation by extracellular matrix interaction was recently implicated in nuclear actin polymerization through the linker of nucleoskeleton and cytoskeleton (LINC) complex. Some of these extracellular cues known so far appear to converge at the level of nuclear formin activity and subsequent regulation of myocardin-related transcription factors. Nevertheless, as the precise signaling events are as yet unknown, the regulation of nuclear actin polymerization may be of significant importance for different cellular functions as well as disease conditions caused by altered nuclear dynamics and architecture.
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25
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Morrissey JB, Cheng RY, Davoudi S, Gilbert PM. Biomechanical Origins of Muscle Stem Cell Signal Transduction. J Mol Biol 2015; 428:1441-54. [PMID: 26004541 DOI: 10.1016/j.jmb.2015.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 05/03/2015] [Accepted: 05/06/2015] [Indexed: 10/23/2022]
Abstract
Skeletal muscle, the most abundant and widespread tissue in the human body, contracts upon receiving electrochemical signals from the nervous system to support essential functions such as thermoregulation, limb movement, blinking, swallowing and breathing. Reconstruction of adult muscle tissue relies on a pool of mononucleate, resident muscle stem cells, known as "satellite cells", expressing the paired-box transcription factor Pax7 necessary for their specification during embryonic development and long-term maintenance during adult life. Satellite cells are located around the myofibres in a niche at the interface of the basal lamina and the host fibre plasma membrane (i.e., sarcolemma), at a very low frequency. Upon damage to the myofibres, quiescent satellite cells are activated and give rise to a population of transient amplifying myogenic progenitor cells, which eventually exit the cell cycle permanently and fuse to form new myofibres and regenerate the tissue. A subpopulation of satellite cells self-renew and repopulate the niche, poised to respond to future demands. Harnessing the potential of satellite cells relies on a complete understanding of the molecular mechanisms guiding their regulation in vivo. Over the past several decades, studies revealed many signal transduction pathways responsible for satellite cell fate decisions, but the niche cues driving the activation and silencing of these pathways are less clear. Here we explore the scintillating possibility that considering the dynamic changes in the biophysical properties of the skeletal muscle, namely stiffness, and the stretch and shear forces to which a myofibre can be subjected to may provide missing information necessary to gain a full understanding of satellite cell niche regulation.
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Affiliation(s)
- James B Morrissey
- Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada M5S3G9; Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada M5S3E1
| | - Richard Y Cheng
- Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada M5S3G9; Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada M5S3E1
| | - Sadegh Davoudi
- Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada M5S3G9; Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada M5S3E1
| | - Penney M Gilbert
- Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada M5S3G9; Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada M5S3E1.
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Shiwen X, Stratton R, Nikitorowicz-Buniak J, Ahmed-Abdi B, Ponticos M, Denton C, Abraham D, Takahashi A, Suki B, Layne MD, Lafyatis R, Smith BD. A Role of Myocardin Related Transcription Factor-A (MRTF-A) in Scleroderma Related Fibrosis. PLoS One 2015; 10:e0126015. [PMID: 25955164 PMCID: PMC4425676 DOI: 10.1371/journal.pone.0126015] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/27/2015] [Indexed: 02/07/2023] Open
Abstract
In scleroderma (systemic sclerosis, SSc), persistent activation of myofibroblast leads to severe skin and organ fibrosis resistant to therapy. Increased mechanical stiffness in the involved fibrotic tissues is a hallmark clinical feature and a cause of disabling symptoms. Myocardin Related Transcription Factor-A (MRTF-A) is a transcriptional co-activator that is sequestered in the cytoplasm and translocates to the nucleus under mechanical stress or growth factor stimulation. Our objective was to determine if MRTF-A is activated in the disease microenvironment to produce more extracellular matrix in progressive SSc. Immunohistochemistry studies demonstrate that nuclear translocation of MRTF-A in scleroderma tissues occurs in keratinocytes, endothelial cells, infiltrating inflammatory cells, and dermal fibroblasts, consistent with enhanced signaling in multiple cell lineages exposed to the stiff extracellular matrix. Inhibition of MRTF-A nuclear translocation or knockdown of MRTF-A synthesis abolishes the SSc myofibroblast enhanced basal contractility and synthesis of type I collagen and inhibits the matricellular profibrotic protein, connective tissue growth factor (CCN2/CTGF). In MRTF-A null mice, basal skin and lung stiffness was abnormally reduced and associated with altered fibrillar collagen. MRTF-A has a role in SSc fibrosis acting as a central regulator linking mechanical cues to adverse remodeling of the extracellular matrix.
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Affiliation(s)
- Xu Shiwen
- Centre for Rheumatology and Connective Tissue Diseases, University College London, Royal Free Campus, London, United Kingdom
| | - Richard Stratton
- Centre for Rheumatology and Connective Tissue Diseases, University College London, Royal Free Campus, London, United Kingdom
| | - Joanna Nikitorowicz-Buniak
- Centre for Rheumatology and Connective Tissue Diseases, University College London, Royal Free Campus, London, United Kingdom
| | - Bahja Ahmed-Abdi
- Centre for Rheumatology and Connective Tissue Diseases, University College London, Royal Free Campus, London, United Kingdom
| | - Markella Ponticos
- Centre for Rheumatology and Connective Tissue Diseases, University College London, Royal Free Campus, London, United Kingdom
| | - Christopher Denton
- Centre for Rheumatology and Connective Tissue Diseases, University College London, Royal Free Campus, London, United Kingdom
| | - David Abraham
- Centre for Rheumatology and Connective Tissue Diseases, University College London, Royal Free Campus, London, United Kingdom
| | - Ayuko Takahashi
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Bela Suki
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Matthew D. Layne
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Robert Lafyatis
- Rheumatology Department, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Barbara D. Smith
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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27
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Cyclic stretching of soft substrates induces spreading and growth. Nat Commun 2015; 6:6333. [PMID: 25704457 PMCID: PMC4346610 DOI: 10.1038/ncomms7333] [Citation(s) in RCA: 201] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 01/19/2015] [Indexed: 02/07/2023] Open
Abstract
In the body, soft tissues often undergo cycles of stretching and relaxation that may affect cell behaviour without changing matrix rigidity. To determine whether transient forces can substitute for a rigid matrix, we stretched soft pillar arrays. Surprisingly, 1–5% cyclic stretching over a frequency range of 0.01–10 Hz caused spreading and stress fibre formation (optimum 0.1 Hz) that persisted after 4 h of stretching. Similarly, stretching increased cell growth rates on soft pillars comparative to rigid substrates. Of possible factors linked to fibroblast growth, MRTF-A (myocardin-related transcription factor-A) moved to the nucleus in 2 h of cyclic stretching and reversed on cessation; but YAP (Yes-associated protein) moved much later. Knockdown of either MRTF-A or YAP blocked stretch-dependent growth. Thus, we suggest that the repeated pulling from a soft matrix can substitute for a stiff matrix in stimulating spreading, stress fibre formation and growth. Cells grown on a stiff substrate are stimulated through physical cues to spread, create actin stress fibres and proliferate. Here Cui et al. show that cyclic stretching cells on a soft pillar substrate has the same effect as growth on a stiff substrate, and results in nuclear translocation of YAP and MRTF-A.
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García E, Machesky LM, Jones GE, Antón IM. WIP is necessary for matrix invasion by breast cancer cells. Eur J Cell Biol 2014; 93:413-23. [PMID: 25169059 DOI: 10.1016/j.ejcb.2014.07.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 07/28/2014] [Accepted: 07/30/2014] [Indexed: 11/20/2022] Open
Abstract
Actin filament assembly and reorganisation during cell migration and invasion into extracellular matrices is a well-documented phenomenon. Among actin-binding proteins regulating its polymerisation, the members of the WASP (Wiskott Aldrich Syndrome Protein) family are generally thought to play the most significant role in supporting cell invasiveness. In situ, cytosolic N-WASP (neural WASP) is associated with a partner protein termed WIP (WASP Interacting Protein) that is bound to the N-terminal domain of N-WASP. Despite much effort, rather little is known about the role of WIP in regulating N-WASP and consequent actin-filament assembly. Even less is known about the function of WIP within the specialised cell adhesion and attachment structures known as podosomes and invadopodia. In particular, whilst the interaction of WIP with known participants in the development and maturation of invadopodia such as N-WASP, the Arp2/3 complex and cortactin has been described, little is known concerning the direct contribution of WIP to invadopodia and its potential role as a regulator of cancer cell invasion. In this report, we use 2D and 3D culture systems to describe the role played by WIP in modulating the morphology and invasiveness of metastatic breast cancer cells in vitro, as well as its effect on the process of mesenchymal-epithelial transition (MET) seen in these cells. We demonstrate that WIP is necessary for invadopodium formation and matrix degradation by basal breast cancer cells, but not sufficient to induce invasiveness in luminal cells.
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Affiliation(s)
- Esther García
- Department of Cellular and Molecular Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus UAM Cantoblanco, Darwin 3, 28049 Madrid, Spain.
| | - Laura M Machesky
- The Beatson Institute for Cancer Research, Bearsden, Glasgow G61 1BD, Scotland, UK.
| | - Gareth E Jones
- Randall Division of Cell & Molecular Biophysics, King's College London, London SE1 1UL, UK.
| | - Inés M Antón
- Department of Cellular and Molecular Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus UAM Cantoblanco, Darwin 3, 28049 Madrid, Spain.
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Salvany L, Muller J, Guccione E, Rørth P. The core and conserved role of MAL is homeostatic regulation of actin levels. Genes Dev 2014; 28:1048-53. [PMID: 24831700 PMCID: PMC4035534 DOI: 10.1101/gad.237743.114] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The transcription cofactor MAL is regulated by actin dynamics and, together with its DNA-binding partner, SRF, is required for invasive cell migration. Salvany et al. show in Drosophila and human cellular models that actin is the key target that must be regulated by MAL/SRF for invasive cell migration. By regulating MAL/SRF, actin feeds back on the production of actin mRNA to ensure sufficient actin supply. Actin and MAL thus form a homeostatic feedback system that provides the foundation for actin dynamics required for complex cell behavior. The transcription cofactor MAL is regulated by free actin levels and thus by actin dynamics. MAL, together with its DNA-binding partner, SRF, is required for invasive cell migration and in experimental metastasis. Although MAL/SRF has many targets, we provide genetic evidence in both Drosophila and human cellular models that actin is the key target that must be regulated by MAL/SRF for invasive cell migration. By regulating MAL/SRF activity, actin protein feeds back on production of actin mRNA to ensure sufficient supply of actin. This constitutes a dedicated homeostatic feedback system that provides a foundation for cellular actin dynamics.
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Affiliation(s)
- Lara Salvany
- Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Julius Muller
- Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Ernesto Guccione
- Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Pernille Rørth
- Institute of Molecular and Cell Biology, Singapore 138673, Singapore
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30
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Li H, Fitchett C, Kozdon K, Jayaram H, Rose GE, Bailly M, Ezra DG. Independent adipogenic and contractile properties of fibroblasts in Graves' orbitopathy: an in vitro model for the evaluation of treatments. PLoS One 2014; 9:e95586. [PMID: 24751986 PMCID: PMC3994071 DOI: 10.1371/journal.pone.0095586] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 03/28/2014] [Indexed: 11/19/2022] Open
Abstract
Graves’ orbitopathy (GO) is a disfiguring and sometimes blinding disease, characterised by inflammation and swelling of orbital tissues, with fibrosis and adipogenesis being predominant features. Little is known about the disease aetiology and the molecular mechanisms driving the phenotypic changes in orbital fibroblasts are unknown. Using fibroblasts isolated from the orbital fat of undiseased individuals or GO patients, we have established a novel in vitro model to evaluate the dual profile of GO cells in a three-dimensional collagen matrix; this pseudo-physiological 3D environment allows measurement of their contractile and adipogenic properties. GO cells contracted collagen matrices more efficiently than control cells following serum or TGFβ1 stimulation, and showed a slightly increased ability to proliferate in the 3D matrix, in accordance with a fibro-proliferative phenotype. GO cells, unlike controls, also spontaneously differentiated into adipocytes in 3D cultures - confirming an intrinsic adipogenic profile. However, both control and GO cells underwent adipogenesis when cultured under pathological pressure levels. We further demonstrate that a Thy-1-low population of GO cells underlies the adipogenic - but not the contractile - phenotype and, using inhibitors, confirm that the contractile and adipogenic phenotypes are regulated by separate pathways. In view of the current lack of suitable treatment for GO, we propose that this new model testing the duality of the GO phenotype could be useful as a preclinical evaluation for the efficacy of potential treatments.
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Affiliation(s)
- He Li
- Department of Cell Biology, UCL Institute of Ophthalmology, London, United Kingdom
| | - Caroline Fitchett
- Department of Cell Biology, UCL Institute of Ophthalmology, London, United Kingdom
| | - Katarzyna Kozdon
- Department of Cell Biology, UCL Institute of Ophthalmology, London, United Kingdom
| | - Hari Jayaram
- Department of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, United Kingdom
| | - Geoffrey E. Rose
- Department of Cell Biology, UCL Institute of Ophthalmology, London, United Kingdom
- Moorfields Eye Hospital, and the National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, UCL Partners AHSC, London, United Kingdom
| | - Maryse Bailly
- Department of Cell Biology, UCL Institute of Ophthalmology, London, United Kingdom
- * E-mail:
| | - Daniel G. Ezra
- Department of Cell Biology, UCL Institute of Ophthalmology, London, United Kingdom
- Moorfields Eye Hospital, and the National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, UCL Partners AHSC, London, United Kingdom
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31
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Ricca BL, Venugopalan G, Fletcher DA. To pull or be pulled: parsing the multiple modes of mechanotransduction. Curr Opin Cell Biol 2013; 25:558-64. [PMID: 23830123 DOI: 10.1016/j.ceb.2013.06.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 06/09/2013] [Indexed: 01/16/2023]
Abstract
A cell embedded in a multicellular organism will experience a wide range of mechanical stimuli over the course of its life. Fluid flows and neighboring cells actively exert stresses on the cell, while the cell's environment presents a set of passive mechanical properties that constrain its physical behavior. Cells respond to these varied mechanical cues through biological responses that regulate activities such as differentiation, morphogenesis, and proliferation, as well as material responses involving compression, stretching, and relaxation. Here, we break down recent studies of mechanotransduction on the basis of the input mechanical stimuli acting upon the cell and the output response of the cell. This framework provides a useful starting point for identifying overlaps in molecular players and sensing modalities, and it highlights how different timescales involved in biological and material responses to mechanical inputs could serve as a means for filtering important mechanical signals from noise.
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Affiliation(s)
- Benjamin L Ricca
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, 648 Stanley Hall, Berkeley, CA 94720, USA
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32
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Cell geometric constraints induce modular gene-expression patterns via redistribution of HDAC3 regulated by actomyosin contractility. Proc Natl Acad Sci U S A 2013; 110:11349-54. [PMID: 23798429 DOI: 10.1073/pnas.1300801110] [Citation(s) in RCA: 253] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Physical forces in the form of substrate rigidity or geometrical constraints have been shown to alter gene expression profile and differentiation programs. However, the underlying mechanism of gene regulation by these mechanical cues is largely unknown. In this work, we use micropatterned substrates to alter cellular geometry (shape, aspect ratio, and size) and study the nuclear mechanotransduction to regulate gene expression. Genome-wide transcriptome analysis revealed cell geometry-dependent alterations in actin-related gene expression. Increase in cell size reinforced expression of matrix-related genes, whereas reduced cell-substrate contact resulted in up-regulation of genes involved in cellular homeostasis. We also show that large-scale changes in gene-expression profile mapped onto differential modulation of nuclear morphology, actomyosin contractility and histone acetylation. Interestingly, cytoplasmic-to-nuclear redistribution of histone deacetylase 3 modulated histone acetylation in an actomyosin-dependent manner. In addition, we show that geometric constraints altered the nuclear fraction of myocardin-related transcription factor. These fractions exhibited hindered diffusion time scale within the nucleus, correlated with enhanced serum-response element promoter activity. Furthermore, nuclear accumulation of myocardin-related transcription factor also modulated NF-κB activity. Taken together, our work provides modularity in switching gene-expression patterns by cell geometric constraints via actomyosin contractility.
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33
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Calvo F, Ege N, Grande-Garcia A, Hooper S, Jenkins RP, Chaudhry SI, Harrington K, Williamson P, Moeendarbary E, Charras G, Sahai E. Mechanotransduction and YAP-dependent matrix remodelling is required for the generation and maintenance of cancer-associated fibroblasts. Nat Cell Biol 2013; 15:637-46. [PMID: 23708000 PMCID: PMC3836234 DOI: 10.1038/ncb2756] [Citation(s) in RCA: 988] [Impact Index Per Article: 89.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 04/12/2013] [Indexed: 12/14/2022]
Abstract
To learn more about cancer-associated fibroblasts (CAFs), we have isolated fibroblasts from different stages of breast cancer progression and analysed their function and gene expression. These analyses reveal that activation of the YAP transcription factor is a signature feature of CAFs. YAP function is required for CAFs to promote matrix stiffening, cancer cell invasion and angiogenesis. Remodelling of the ECM and promotion of cancer cell invasion requires the actomyosin cytoskeleton. YAP regulates the expression of several cytoskeletal regulators, including ANLN and DIAPH3, and controls the protein levels of MYL9 (also known as MLC2). Matrix stiffening further enhances YAP activation, thus establishing a feed-forward self-reinforcing loop that helps to maintain the CAF phenotype. Actomyosin contractility and Src function are required for YAP activation by stiff matrices. Further, transient ROCK inhibition is able to disrupt the feed-forward loop, leading to a long-lasting reversion of the CAF phenotype.
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Affiliation(s)
- Fernando Calvo
- Tumour Cell Biology Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London, WC2A 3LY, UK
| | - Nil Ege
- Tumour Cell Biology Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London, WC2A 3LY, UK
| | - Araceli Grande-Garcia
- Tumour Cell Biology Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London, WC2A 3LY, UK
- Centro Nacional de Investigaciones Oncológicas, C/ Melchor Fernández Almagro, 3, E-28029 Madrid, Spain
| | - Steven Hooper
- Tumour Cell Biology Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London, WC2A 3LY, UK
| | - Robert P. Jenkins
- Tumour Cell Biology Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London, WC2A 3LY, UK
| | - Shahid I. Chaudhry
- Tumour Cell Biology Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London, WC2A 3LY, UK
- Oral Medicine, UCL Eastman Dental Institute and UCLHT Eastman Dental Hospital, London, UK
| | - Kevin Harrington
- Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - Peter Williamson
- Thomas Tatum Head and Neck Unit, St George’s Hospital, London, UK
| | - Emad Moeendarbary
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, UK
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, UK
| | - Erik Sahai
- Tumour Cell Biology Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London, WC2A 3LY, UK
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Van De Water L, Varney S, Tomasek JJ. Mechanoregulation of the Myofibroblast in Wound Contraction, Scarring, and Fibrosis: Opportunities for New Therapeutic Intervention. Adv Wound Care (New Rochelle) 2013; 2:122-141. [PMID: 24527336 DOI: 10.1089/wound.2012.0393] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Indexed: 12/31/2022] Open
Abstract
SIGNIFICANCE Myofibroblasts are responsible for wound closure that occurs in healed acute wounds. However, their actions can result in disfiguring scar contractures, compromised organ function, and a tumor promoting stroma. Understanding the mechanisms regulating their contractile machinery, gene expression, and lifespan is essential to develop new therapies to control their function. RECENT ADVANCES Mechanical stress and transforming growth factor beta-1 (TGF-β1) regulate myofibroblast differentiation from mesenchymal progenitors. As these precursor cells differentiate, they assemble a contractile apparatus to generate the force used to contract wounds. The mechanisms by which mechanical stress promote expression of contractile genes through the TGF-β1 and serum response factor pathways and offer therapeutic targets to limit myofibroblast function are being elucidated. CRITICAL ISSUES Emerging evidence suggests that the integration of mechanical cues with intracellular signaling pathways is critical to myofibroblast function via its effects on gene expression, cellular contraction, and paracrine signaling with neighboring cells. In addition, while apoptosis is clearly one pathway that can limit myofibroblast lifespan, recent data suggest that pathogenic myofibroblasts can become senescent and adopt a more beneficial phenotype, or may revert to a quiescent state, thereby limiting their function. FUTURE DIRECTIONS Given the important role that myofibroblasts play in pathologies as disparate as cutaneous scarring, organ fibrosis, and tumor progression, knowledge gained in the areas of intracellular signaling networks, mechanical signal transduction, extracellular matrix biology, and cell fate will support efforts to develop new therapies with a wide impact.
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Affiliation(s)
| | - Scott Varney
- Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York
| | - James J. Tomasek
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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35
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Induction of megakaryocyte differentiation drives nuclear accumulation and transcriptional function of MKL1 via actin polymerization and RhoA activation. Blood 2012; 121:1094-101. [PMID: 23243284 DOI: 10.1182/blood-2012-05-429993] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
How components of the cytoskeleton regulate complex cellular responses is fundamental to understanding cellular function. Megakaryoblast leukemia 1 (MKL1), an activator of serum response factor (SRF) transcriptional activity, promotes muscle, neuron, and megakaryocyte differentiation. In muscle cells, where MKL1 subcellular localization is one mechanism by which cells control SRF activity, MKL1 translocation from the cytoplasm to the nucleus in response to actin polymerization is critical for its function as a transcriptional regulator. MKL1 localization is cell-type specific; it is predominantly cytoplasmic in unstimulated fibroblasts and some muscle cell types and is constitutively nuclear in neuronal cells. In the present study, we report that in megakaryocytes, subcellular localization and regulation of MKL1 is dependent on RhoA activity and actin organization. Induction of megakaryocytic differentiation of human erythroleukemia cells by 12-O-tetradecanoylphorbol-13-acetate and primary megakaryocytes by thrombopoietin promotes MKL1 nuclear localization. This MKL1 localization is blocked by drugs inhibiting RhoA activity or actin polymerization.We also show that nuclear-localized MKL1 activates the transcription of SRF target genes. This report broadens our knowledge of the molecular mechanisms regulating megakaryocyte differentiation.
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36
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Iyer KV, Pulford S, Mogilner A, Shivashankar GV. Mechanical activation of cells induces chromatin remodeling preceding MKL nuclear transport. Biophys J 2012; 103:1416-28. [PMID: 23062334 DOI: 10.1016/j.bpj.2012.08.041] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 07/30/2012] [Accepted: 08/16/2012] [Indexed: 10/27/2022] Open
Abstract
For cells to adapt to different tissues and changes in tissue mechanics, they must be able to respond to mechanical cues by changing their gene expression patterns. Biochemical signaling pathways for these responses have been elucidated, and recent evidence points to the involvement of force-induced deformation of the nucleus. However, it is still unclear how physical cues received at the plasma membrane (PM) spatiotemporally integrate to the functional chromatin organization of the cell nucleus. To investigate this issue, we applied mechanical forces through magnetic particles adhered to the PM of single cells and mapped the accompanying changes in actin polymerization, nuclear morphology, chromatin remodeling, and nuclear transport of soluble signaling intermediates using high-resolution fluorescence anisotropy imaging. Using this approach, we show the timescales associated with force-induced polymerization of actin and changes in the F/G actin ratio resulting in nuclear translocation of the G-actin-associated transcriptional cofactor, megakaryoblastic acute leukemia factor-1 (MKL). Further, this method of measuring nuclear organization at high spatiotemporal resolution with simultaneous force application revealed the physical propagation of forces to the nucleus, resulting in changes to chromatin organization, followed by nuclear deformation. We also describe a quantitative model that incorporates active stresses and chemical kinetics to evaluate the observed timescales. Our work suggests that mechanical activation of cells is accompanied by distinct timescales involved in the reorganization of actin and chromatin assembly, followed by translocation of transcription cofactors from the cytoplasm to the nucleus.
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Affiliation(s)
- K Venkatesan Iyer
- Mechanobiology Institute, National University of Singapore, Singapore
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37
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Small EM. The actin-MRTF-SRF gene regulatory axis and myofibroblast differentiation. J Cardiovasc Transl Res 2012; 5:794-804. [PMID: 22898751 DOI: 10.1007/s12265-012-9397-0] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 08/01/2012] [Indexed: 12/14/2022]
Abstract
Cardiac fibroblasts are responsible for necrotic tissue replacement and scar formation after myocardial infarction (MI) and contribute to remodeling in response to pathological stimuli. This response to insult or injury is largely due to the phenotypic plasticity of fibroblasts. When fibroblasts encounter environmental disturbances, whether biomechanical or humoral, they often transform into smooth muscle-like, contractile cells called "myofibroblasts." The signals that control myofibroblast differentiation include the transforming growth factor (TGF)-β1-Smad pathway and Rho GTPase-dependent actin polymerization. Recent evidence implicates serum response factor (SRF) and the myocardin-related transcription factors (MRTFs) as key mediators of the contractile gene program in response to TGF-β1 or RhoA signaling. This review highlights the function of myofibroblasts in cardiac remodeling and the role of the actin-MRTF-SRF signaling axis in regulating this process.
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Affiliation(s)
- Eric M Small
- Aab Cardiovascular Research Institute, Department of Medicine, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Avenue, Box CVRI, Rochester, NY 14642, USA.
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38
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Mammoto A, Mammoto T, Ingber DE. Mechanosensitive mechanisms in transcriptional regulation. J Cell Sci 2012; 125:3061-73. [PMID: 22797927 DOI: 10.1242/jcs.093005] [Citation(s) in RCA: 282] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Transcriptional regulation contributes to the maintenance of pluripotency, self-renewal and differentiation in embryonic cells and in stem cells. Therefore, control of gene expression at the level of transcription is crucial for embryonic development, as well as for organogenesis, functional adaptation, and regeneration in adult tissues and organs. In the past, most work has focused on how transcriptional regulation results from the complex interplay between chemical cues, adhesion signals, transcription factors and their co-regulators during development. However, chemical signaling alone is not sufficient to explain how three-dimensional (3D) tissues and organs are constructed and maintained through the spatiotemporal control of transcriptional activities. Accumulated evidence indicates that mechanical cues, which include physical forces (e.g. tension, compression or shear stress), alterations in extracellular matrix (ECM) mechanics and changes in cell shape, are transmitted to the nucleus directly or indirectly to orchestrate transcriptional activities that are crucial for embryogenesis and organogenesis. In this Commentary, we review how the mechanical control of gene transcription contributes to the maintenance of pluripotency, determination of cell fate, pattern formation and organogenesis, as well as how it is involved in the control of cell and tissue function throughout embryogenesis and adult life. A deeper understanding of these mechanosensitive transcriptional control mechanisms should lead to new approaches to tissue engineering and regenerative medicine.
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Affiliation(s)
- Akiko Mammoto
- Vascular Biology Program, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
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