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Baek J, Kumar S, Schaffer DV. Dynamic light-responsive RhoA activity regulates mechanosensitive stem cell fate decision in 3D matrices. BIOMATERIALS ADVANCES 2024; 160:213836. [PMID: 38599042 DOI: 10.1016/j.bioadv.2024.213836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/05/2024] [Accepted: 03/19/2024] [Indexed: 04/12/2024]
Abstract
The behavior of stem cells is regulated by mechanical cues in their niche that continuously vary due to extracellular matrix (ECM) remodeling, pulsated mechanical stress exerted by blood flow, and/or cell migration. However, it is still unclear how dynamics of mechanical cues influence stem cell lineage commitment, especially in a 3D microenvironment where mechanosensing differs from that in a 2D microenvironment. In the present study, we investigated how temporally varying mechanical signaling regulates expression of the early growth response 1 gene (Egr1), which we recently discovered to be a 3D matrix-specific mediator of mechanosensitive neural stem cell (NSC) lineage commitment. Specifically, we temporally controlled the activity of Ras homolog family member A (RhoA), which is known to have a central role in mechanotransduction, using our previously developed Arabidopsis thaliana cryptochrome-2-based optoactivation system. Interestingly, pulsed RhoA activation induced Egr1 upregulation in stiff 3D gels only, whereas static light stimulation induced an increase in Egr1 expression across a wide range of 3D gel stiffnesses. Actin assembly inhibition limited Egr1 upregulation upon RhoA activation, implying that RhoA signaling requires an actin-involved process to upregulate Egr1. Consistently, static-light RhoA activation rather than pulsed-light activation restricted neurogenesis in soft gels. Our findings indicate that the dynamics of RhoA activation influence Egr1-mediated stem cell fate within 3D matrices in a matrix stiffness-dependent manner.
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Affiliation(s)
- Jieung Baek
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Bioengineering, University of California, Berkeley, CA 94720, USA; Division of Mechanical and Biomedical Engineering, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Sanjay Kumar
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Bioengineering, University of California, Berkeley, CA 94720, USA.
| | - David V Schaffer
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Bioengineering, University of California, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, Berkeley, CA 94720, USA.
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Baek J, Lopez PA, Lee S, Kim TS, Kumar S, Schaffer DV. Egr1 is a 3D matrix-specific mediator of mechanosensitive stem cell lineage commitment. SCIENCE ADVANCES 2022; 8:eabm4646. [PMID: 35427160 PMCID: PMC9012469 DOI: 10.1126/sciadv.abm4646] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 02/28/2022] [Indexed: 05/31/2023]
Abstract
While extracellular matrix (ECM) mechanics strongly regulate stem cell commitment, the field's mechanistic understanding of this phenomenon largely derives from simplified two-dimensional (2D) culture substrates. Here, we found a 3D matrix-specific mechanoresponsive mechanism for neural stem cell (NSC) differentiation. NSC lineage commitment in 3D is maximally stiffness sensitive in the range of 0.1 to 1.2 kPa, a narrower and more brain-mimetic range than we had previously identified in 2D (0.75 to 75 kPa). Transcriptomics revealed stiffness-dependent up-regulation of early growth response 1 (Egr1) in 3D but not in 2D. Egr1 knockdown enhanced neurogenesis in stiff ECMs by driving β-catenin nuclear localization and activity in 3D, but not in 2D. Mechanical modeling and experimental studies under osmotic pressure indicate that stiff 3D ECMs are likely to stimulate Egr1 via increases in confining stress during cell volumetric growth. To our knowledge, Egr1 represents the first 3D-specific stem cell mechanoregulatory factor.
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Affiliation(s)
- Jieung Baek
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Paola A. Lopez
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
- UC Berkeley–UC San Francisco Graduate Program in Bioengineering, Berkeley, CA 94720, USA
| | - Sangmin Lee
- Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Taek-Soo Kim
- Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sanjay Kumar
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
- UC Berkeley–UC San Francisco Graduate Program in Bioengineering, Berkeley, CA 94720, USA
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - David V. Schaffer
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
- UC Berkeley–UC San Francisco Graduate Program in Bioengineering, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Helen Wills Neuroscience Institute, Berkeley, CA 94720, USA
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Karademir D, Todorova V, Ebner LJA, Samardzija M, Grimm C. Single-cell RNA sequencing of the retina in a model of retinitis pigmentosa reveals early responses to degeneration in rods and cones. BMC Biol 2022; 20:86. [PMID: 35413909 PMCID: PMC9006580 DOI: 10.1186/s12915-022-01280-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 03/12/2022] [Indexed: 11/18/2022] Open
Abstract
Background In inherited retinal disorders such as retinitis pigmentosa (RP), rod photoreceptor-specific mutations cause primary rod degeneration that is followed by secondary cone death and loss of high-acuity vision. Mechanistic studies of retinal degeneration are challenging because of retinal heterogeneity. Moreover, the detection of early cone responses to rod death is especially difficult due to the paucity of cones in the retina. To resolve heterogeneity in the degenerating retina and investigate events in both types of photoreceptors during primary rod degeneration, we utilized droplet-based single-cell RNA sequencing in an RP mouse model, rd10. Results Using trajectory analysis, we defined two consecutive phases of rod degeneration at P21, characterized by the early transient upregulation of Egr1 and the later induction of Cebpd. EGR1 was the transcription factor most significantly associated with the promoters of differentially regulated genes in Egr1-positive rods in silico. Silencing Egr1 affected the expression levels of two of these genes in vitro. Degenerating rods exhibited changes associated with metabolism, neuroprotection, and modifications to synapses and microtubules. Egr1 was also the most strongly upregulated transcript in cones. Its upregulation in cones accompanied potential early respiratory dysfunction and changes in signaling pathways. The expression pattern of EGR1 in the retina was dynamic during degeneration, with a transient increase of EGR1 immunoreactivity in both rods and cones during the early stages of their degenerative processes. Conclusion Our results identify early and late changes in degenerating rd10 rod photoreceptors and reveal early responses to rod degeneration in cones not expressing the disease-causing mutation, pointing to mechanisms relevant for secondary cone degeneration. In addition, our data implicate EGR1 as a potential key regulator of early degenerative events in rods and cones, providing a potential broad target for modulating photoreceptor degeneration. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01280-9.
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Affiliation(s)
- Duygu Karademir
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Zurich, Switzerland. .,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
| | - Vyara Todorova
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Lynn J A Ebner
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Marijana Samardzija
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Christian Grimm
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
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Duclot F, Kabbaj M. The Role of Early Growth Response 1 (EGR1) in Brain Plasticity and Neuropsychiatric Disorders. Front Behav Neurosci 2017; 11:35. [PMID: 28321184 PMCID: PMC5337695 DOI: 10.3389/fnbeh.2017.00035] [Citation(s) in RCA: 195] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/21/2017] [Indexed: 12/11/2022] Open
Abstract
It is now clearly established that complex interactions between genes and environment are involved in multiple aspects of neuropsychiatric disorders, from determining an individual's vulnerability to onset, to influencing its response to therapeutic intervention. In this perspective, it appears crucial to better understand how the organism reacts to environmental stimuli and provide a coordinated and adapted response. In the central nervous system, neuronal plasticity and neurotransmission are among the major processes integrating such complex interactions between genes and environmental stimuli. In particular, immediate early genes (IEGs) are critical components of these interactions as they provide the molecular framework for a rapid and dynamic response to neuronal activity while opening the possibility for a lasting and sustained adaptation through regulation of the expression of a wide range of genes. As a result, IEGs have been tightly associated with neuronal activity as well as a variety of higher order processes within the central nervous system such as learning, memory and sensitivity to reward. The immediate early gene and transcription factor early growth response 1 (EGR1) has thus been revealed as a major mediator and regulator of synaptic plasticity and neuronal activity in both physiological and pathological conditions. In this review article, we will focus on the role of EGR1 in the central nervous system. First, we will summarize the different factors influencing its activity. Then, we will analyze the amount of data, including genome-wide, that has emerged in the recent years describing the wide variety of genes, pathways and biological functions regulated directly or indirectly by EGR1. We will thus be able to gain better insights into the mechanisms underlying EGR1's functions in physiological neuronal activity. Finally, we will discuss and illustrate the role of EGR1 in pathological states with a particular interest in cognitive functions and neuropsychiatric disorders.
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Affiliation(s)
- Florian Duclot
- Department of Biomedical Sciences, Florida State UniversityTallahassee, FL, USA; Program in Neuroscience, Florida State UniversityTallahassee, FL, USA
| | - Mohamed Kabbaj
- Department of Biomedical Sciences, Florida State UniversityTallahassee, FL, USA; Program in Neuroscience, Florida State UniversityTallahassee, FL, USA
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Rougerie P, Delon J. Rho GTPases: masters of T lymphocyte migration and activation. Immunol Lett 2011; 142:1-13. [PMID: 22207038 DOI: 10.1016/j.imlet.2011.12.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 11/24/2011] [Accepted: 12/07/2011] [Indexed: 12/15/2022]
Abstract
Rho GTPases are key signal transducer elements activated in T cells by both chemokine and antigen receptors. These two signalling pathways control the two main functions of T lymphocytes: motility and activation. Rho GTPases are thus crucial for the development of an adequate immune response. In this review, we mostly focus on the roles of RhoA, Rac1 and Cdc42 in T cells. We show their importance in phenomena such as adhesion, morphological polarization, migration and antigen recognition.
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Affiliation(s)
- Pablo Rougerie
- Institut Cochin, Université Paris Descartes, Sorbonne Paris Cité, CNRS (UMR 8104), Paris, France; Inserm, U1016, Paris, France
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Riveros C, Mellor D, Gandhi KS, McKay FC, Cox MB, Berretta R, Vaezpour SY, Inostroza-Ponta M, Broadley SA, Heard RN, Vucic S, Stewart GJ, Williams DW, Scott RJ, Lechner-Scott J, Booth DR, Moscato P. A transcription factor map as revealed by a genome-wide gene expression analysis of whole-blood mRNA transcriptome in multiple sclerosis. PLoS One 2010; 5:e14176. [PMID: 21152067 PMCID: PMC2995726 DOI: 10.1371/journal.pone.0014176] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 10/20/2010] [Indexed: 12/03/2022] Open
Abstract
Background Several lines of evidence suggest that transcription factors are involved in the pathogenesis of Multiple Sclerosis (MS) but complete mapping of the whole network has been elusive. One of the reasons is that there are several clinical subtypes of MS and transcription factors that may be involved in one subtype may not be in others. We investigate the possibility that this network could be mapped using microarray technologies and contemporary bioinformatics methods on a dataset derived from whole blood in 99 untreated MS patients (36 Relapse Remitting MS, 43 Primary Progressive MS, and 20 Secondary Progressive MS) and 45 age-matched healthy controls. Methodology/Principal Findings We have used two different analytical methodologies: a non-standard differential expression analysis and a differential co-expression analysis, which have converged on a significant number of regulatory motifs that are statistically overrepresented in genes that are either differentially expressed (or differentially co-expressed) in cases and controls (e.g., V$KROX_Q6, p-value <3.31E-6; V$CREBP1_Q2, p-value <9.93E-6, V$YY1_02, p-value <1.65E-5). Conclusions/Significance Our analysis uncovered a network of transcription factors that potentially dysregulate several genes in MS or one or more of its disease subtypes. The most significant transcription factor motifs were for the Early Growth Response EGR/KROX family, ATF2, YY1 (Yin and Yang 1), E2F-1/DP-1 and E2F-4/DP-2 heterodimers, SOX5, and CREB and ATF families. These transcription factors are involved in early T-lymphocyte specification and commitment as well as in oligodendrocyte dedifferentiation and development, both pathways that have significant biological plausibility in MS causation.
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Affiliation(s)
- Carlos Riveros
- Centre for Bioinformatics, Biomarker Discovery & Information-Based Medicine, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
| | - Drew Mellor
- Centre for Bioinformatics, Biomarker Discovery & Information-Based Medicine, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
- School of Computer Science and Software Engineering, The University of Western Australia, Crawley, Australia
| | - Kaushal S. Gandhi
- Westmead Millennium Institute, University of Sydney, Westmead, Australia
| | - Fiona C. McKay
- Westmead Millennium Institute, University of Sydney, Westmead, Australia
| | - Mathew B. Cox
- Centre for Bioinformatics, Biomarker Discovery & Information-Based Medicine, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
- Hunter Medical Research Institute, Newcastle, Australia
| | - Regina Berretta
- Centre for Bioinformatics, Biomarker Discovery & Information-Based Medicine, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
| | - S. Yahya Vaezpour
- Centre for Bioinformatics, Biomarker Discovery & Information-Based Medicine, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
- Department of Computer Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Mario Inostroza-Ponta
- Centre for Bioinformatics, Biomarker Discovery & Information-Based Medicine, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Santiago, Chile
| | - Simon A. Broadley
- School of Medicine, Griffith University, Brisbane, Australia
- Department of Neurology, Gold Coast Hospital, Southport, Australia
| | - Robert N. Heard
- Westmead Millennium Institute, University of Sydney, Westmead, Australia
| | - Stephen Vucic
- Westmead Millennium Institute, University of Sydney, Westmead, Australia
| | - Graeme J. Stewart
- Westmead Millennium Institute, University of Sydney, Westmead, Australia
| | | | - Rodney J. Scott
- Centre for Bioinformatics, Biomarker Discovery & Information-Based Medicine, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
| | - Jeanette Lechner-Scott
- Centre for Bioinformatics, Biomarker Discovery & Information-Based Medicine, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
| | - David R. Booth
- Westmead Millennium Institute, University of Sydney, Westmead, Australia
| | - Pablo Moscato
- Centre for Bioinformatics, Biomarker Discovery & Information-Based Medicine, University of Newcastle, and Hunter Medical Research Institute, Newcastle, Australia
- Australian Research Council Centre of Excellence in Bioinformatics, St Lucia, Australia
- * E-mail:
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Finlay DK, Sinclair LV, Feijoo C, Waugh CM, Hagenbeek TJ, Spits H, Cantrell DA. Phosphoinositide-dependent kinase 1 controls migration and malignant transformation but not cell growth and proliferation in PTEN-null lymphocytes. ACTA ACUST UNITED AC 2009; 206:2441-54. [PMID: 19808258 PMCID: PMC2768858 DOI: 10.1084/jem.20090219] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In normal T cell progenitors, phosphoinositide-dependent kinase l (PDK1)–mediated phosphorylation and activation of protein kinase B (PKB) is essential for the phosphorylation and inactivation of Foxo family transcription factors, and also controls T cell growth and proliferation. The current study has characterized the role of PDK1 in the pathology caused by deletion of the tumor suppressor phosphatase and tensin homologue deleted on chromosome 10 (PTEN). PDK1 is shown to be essential for lymphomagenesis caused by deletion of PTEN in T cell progenitors. However, PTEN deletion bypasses the normal PDK1-controlled signaling pathways that determine thymocyte growth and proliferation. PDK1 does have important functions in PTEN-null thymocytes, notably to control the PKB–Foxo signaling axis and to direct the repertoire of adhesion and chemokine receptors expressed by PTEN-null T cells. The results thus provide two novel insights concerning pathological signaling caused by PTEN loss in lymphocytes. First, PTEN deletion bypasses the normal PDK1-controlled metabolic checkpoints that determine cell growth and proliferation. Second, PDK1 determines the cohort of chemokine and adhesion receptors expressed by PTEN-null cells, thereby controlling their migratory capacity.
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Affiliation(s)
- David K Finlay
- Division of Immunology and Cell Biology, University of Dundee, Dundee DD15EH, Scotland, UK
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Abstract
Rho family GTPases, and the proteins that regulate them, have important roles in many cellular processes, including cell division, survival, migration and adhesion. Although most of our understanding of these proteins has come from studies using cell lines, more recent gene targeting studies in mice are providing insights into the in vivo function of these proteins. Here we review recent progress revealing crucial roles for these proteins in lymphocyte development, activation, differentiation and migration. The emerging picture shows that Rho family GTPases transduce signals from receptors for antigens, chemokines and cytokines, as well as adhesion molecules and pattern recognition receptors, and that they function as focal points for crosstalk between different signalling pathways.
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