1
|
Abstract
The identification of myofibroblasts is essential for mechanistic in vitro studies, cell-based drug tests, and to assess the level of fibrosis in experimental animal or human fibrosis. The name myo-fibroblast was chosen in 1971 to express that the formation of contractile features-stress fibers is the essential criterion to define these cells. Additional neo-expression of α-smooth muscle actin (α-SMA) in stress fibers has become the most widely used molecular marker. Here, we briefly introduce the concept of different myofibroblast activation states, of which the highly contractile α-SMA-positive phenotype represents a most advanced functional stage. We provide targeted immunofluorescence protocols to assess this phenotype, and publicly accessible image analysis tools to quantify the level of myofibroblast activation in culture and in tissues.
Collapse
Affiliation(s)
- Fereshteh S Younesi
- Laboratory of Tissue Repair and Regeneration, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - Dong Ok Son
- Laboratory of Tissue Repair and Regeneration, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - Joao Firmino
- Laboratory of Tissue Repair and Regeneration, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada.,Collaborative Advanced Microscopy Laboratories of Dentistry (CAMiLoD), Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - Boris Hinz
- Laboratory of Tissue Repair and Regeneration, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada. .,Collaborative Advanced Microscopy Laboratories of Dentistry (CAMiLoD), Faculty of Dentistry, University of Toronto, Toronto, ON, Canada.
| |
Collapse
|
2
|
Baghdadi MB, Firmino J, Soni K, Evano B, Di Girolamo D, Mourikis P, Castel D, Tajbakhsh S. Notch-Induced miR-708 Antagonizes Satellite Cell Migration and Maintains Quiescence. Cell Stem Cell 2018; 23:859-868.e5. [PMID: 30416072 DOI: 10.1016/j.stem.2018.09.017] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 07/18/2018] [Accepted: 09/27/2018] [Indexed: 12/31/2022]
Abstract
Critical features of stem cells include anchoring within a niche and activation upon injury. Notch signaling maintains skeletal muscle satellite (stem) cell quiescence by inhibiting differentiation and inducing expression of extracellular components of the niche. However, the complete spectrum of how Notch safeguards quiescence is not well understood. Here, we perform Notch ChIP-sequencing and small RNA sequencing in satellite cells and identify the Notch-induced microRNA-708, which is a mirtron that is highly expressed in quiescent cells and sharply downregulated in activated cells. We employ in vivo and ex vivo functional studies, in addition to live imaging, to show that miR-708 regulates quiescence and self-renewal by antagonizing cell migration through targeting the transcripts of the focal-adhesion-associated protein Tensin3. Therefore, this study identifies a Notch-miR708-Tensin3 axis and suggests that Notch signaling can regulate satellite cell quiescence and transition to the activation state through dynamic regulation of the migratory machinery.
Collapse
Affiliation(s)
- Meryem B Baghdadi
- Stem Cells and Development, Department of Developmental & Stem Cell Biology, Institut Pasteur, Paris 75015, France; CNRS UMR 3738, Institut Pasteur, Paris 75015, France; Sorbonne Universités, UPMC, University of Paris 06, IFD-ED 515, Paris 75252, France
| | - Joao Firmino
- Bioimaging and Optics platform (BIOP), School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Kartik Soni
- Stem Cells and Development, Department of Developmental & Stem Cell Biology, Institut Pasteur, Paris 75015, France; CNRS UMR 3738, Institut Pasteur, Paris 75015, France
| | - Brendan Evano
- Stem Cells and Development, Department of Developmental & Stem Cell Biology, Institut Pasteur, Paris 75015, France; CNRS UMR 3738, Institut Pasteur, Paris 75015, France
| | - Daniela Di Girolamo
- Stem Cells and Development, Department of Developmental & Stem Cell Biology, Institut Pasteur, Paris 75015, France; Dipartimento di Medicina Clinica e Chirurgica, Università degli Studi di Napoli Frederico II, 80131 Naples, Italy
| | | | - David Castel
- UMR8203 "Vectorologie et Thérapeutiques Anticancéreuses," CNRS, Gustave Roussy, Université Paris-Sud, Université Paris-Saclay, 94805 Villejuif, France; Département de Cancérologie de l'Enfant et de l'Adolescent, Gustave Roussy, Université Paris-Sud, Université Paris-Saclay, 94805 Villejuif, France
| | - Shahragim Tajbakhsh
- Stem Cells and Development, Department of Developmental & Stem Cell Biology, Institut Pasteur, Paris 75015, France; CNRS UMR 3738, Institut Pasteur, Paris 75015, France.
| |
Collapse
|
3
|
Firmino J, Rocancourt D, Saadaoui M, Moreau C, Gros J. Cell Division Drives Epithelial Cell Rearrangements during Gastrulation in Chick. Dev Cell 2016; 36:249-61. [PMID: 26859350 DOI: 10.1016/j.devcel.2016.01.007] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 11/19/2015] [Accepted: 01/09/2016] [Indexed: 12/25/2022]
Abstract
During early embryonic development, cells are organized as cohesive epithelial sheets that are continuously growing and remodeled without losing their integrity, giving rise to a wide array of tissue shapes. Here, using live imaging in chick embryo, we investigate how epithelial cells rearrange during gastrulation. We find that cell division is a major rearrangement driver that powers dramatic epithelial cell intercalation events. We show that these cell division-mediated intercalations, which represent the majority of epithelial rearrangements within the early embryo, are absolutely necessary for the spatial patterning of gastrulation movements. Furthermore, we demonstrate that these intercalation events result from overall low cortical actomyosin accumulation within the epithelial cells of the embryo, which enables dividing cells to remodel junctions in their vicinity. These findings uncover a role for cell division as coordinator of epithelial growth and remodeling that might underlie various developmental, homeostatic, or pathological processes in amniotes.
Collapse
Affiliation(s)
- Joao Firmino
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France; CNRS URA2578, rue du Dr Roux, 75015 Paris, France
| | - Didier Rocancourt
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France; CNRS URA2578, rue du Dr Roux, 75015 Paris, France
| | - Mehdi Saadaoui
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France; CNRS URA2578, rue du Dr Roux, 75015 Paris, France
| | - Chloe Moreau
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France; CNRS URA2578, rue du Dr Roux, 75015 Paris, France; University Pierre et Marie Curie, Cellule Pasteur UPMC, rue du Dr Roux, 75015 Paris, France
| | - Jerome Gros
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France; CNRS URA2578, rue du Dr Roux, 75015 Paris, France.
| |
Collapse
|