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Mann Z, Lim F, Verma S, Nanavati BN, Davies JM, Begun J, Hardeman EC, Gunning PW, Subramanyam D, Yap AS, Duszyc K. Preexisting tissue mechanical hypertension at adherens junctions disrupts apoptotic extrusion in epithelia. Mol Biol Cell 2024; 35:br3. [PMID: 37903230 PMCID: PMC10881161 DOI: 10.1091/mbc.e23-08-0337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/13/2023] [Accepted: 10/20/2023] [Indexed: 11/01/2023] Open
Abstract
Apical extrusion is a tissue-intrinsic process that allows epithelia to eliminate unfit or surplus cells. This is exemplified by the early extrusion of apoptotic cells, which is critical to maintain the epithelial barrier and prevent inflammation. Apoptotic extrusion is an active mechanical process, which involves mechanotransduction between apoptotic cells and their neighbors, as well as local changes in tissue mechanics. Here we report that the preexisting mechanical tension at adherens junctions (AJs) conditions the efficacy of apoptotic extrusion. Specifically, increasing baseline mechanical tension by overexpression of a phosphomimetic Myosin II regulatory light chain (MRLC) compromises apoptotic extrusion. This occurs when tension is increased in either the apoptotic cell or its surrounding epithelium. Further, we find that the proinflammatory cytokine, TNFα, stimulates Myosin II and increases baseline AJ tension to disrupt apical extrusion, causing apoptotic cells to be retained in monolayers. Importantly, reversal of mechanical tension with an inhibitory MRLC mutant or tropomyosin inhibitors is sufficient to restore apoptotic extrusion in TNFα-treated monolayers. Together, these findings demonstrate that baseline levels of tissue tension are important determinants of apoptotic extrusion, which can potentially be coopted by pathogenetic factors to disrupt the homeostatic response of epithelia to apoptosis.
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Affiliation(s)
- Zoya Mann
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia 4072
| | - Fayth Lim
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia 4072
| | - Suzie Verma
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia 4072
| | - Bageshri N. Nanavati
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia 4072
| | - Julie M. Davies
- Mater Research – The University of Queensland, Woolloongabba, Queensland, Australia 4102
| | - Jakob Begun
- Mater Research – The University of Queensland, Woolloongabba, Queensland, Australia 4102
- Department of Gastroenterology, Mater Hospital Brisbane, South Brisbane, Australia 4101
| | - Edna C. Hardeman
- School of Biomedical Sciences, Faculty of Medicine and Health, Univeristy of New South Wales Sydney, New South Wales, Australia 2052
| | - Peter W. Gunning
- School of Biomedical Sciences, Faculty of Medicine and Health, Univeristy of New South Wales Sydney, New South Wales, Australia 2052
| | - Deepa Subramanyam
- National Centre for Cell Science, Savitribai Phule Pune University, Pune 411007, India
| | - Alpha S. Yap
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia 4072
| | - Kinga Duszyc
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia 4072
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Wee K, Hediyeh-Zadeh S, Duszyc K, Verma S, N Nanavati B, Khare S, Varma A, Daly RJ, Yap AS, Davis MJ, Budnar S. Snail induces epithelial cell extrusion by regulating RhoA contractile signalling and cell-matrix adhesion. J Cell Sci 2020; 133:jcs235622. [PMID: 32467325 DOI: 10.1242/jcs.235622] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 05/14/2020] [Indexed: 01/06/2023] Open
Abstract
Cell extrusion is a morphogenetic process that is implicated in epithelial homeostasis and elicited by stimuli ranging from apoptosis to oncogenic transformation. To explore whether the morphogenetic transcription factor Snail (SNAI1) induces extrusion, we inducibly expressed a stabilized Snail6SA transgene in confluent MCF-7 monolayers. When expressed in small clusters (less than three cells) within otherwise wild-type confluent monolayers, Snail6SA expression induced apical cell extrusion. In contrast, larger clusters or homogenous cultures of Snail6SA cells did not show enhanced apical extrusion, but eventually displayed sporadic basal delamination. Transcriptomic profiling revealed that Snail6SA did not substantively alter the balance of epithelial and mesenchymal genes. However, we identified a transcriptional network that led to upregulated RhoA signalling and cortical contractility in cells expressing Snail6SA Enhanced contractility was necessary, but not sufficient, to drive extrusion, suggesting that Snail collaborates with other factors. Indeed, we found that the transcriptional downregulation of cell-matrix adhesion cooperates with contractility to mediate basal delamination. This provides a pathway for Snail to influence epithelial morphogenesis independently of classic epithelial-to-mesenchymal transition.
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Affiliation(s)
- Kenneth Wee
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Soroor Hediyeh-Zadeh
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia
| | - Kinga Duszyc
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Suzie Verma
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Bageshri N Nanavati
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | | | - Amrita Varma
- Viravecs Laboratories CCAMP, GKVK Campus, Bellary Road, Bangalore, Karnataka 560065, India
| | - Roger J Daly
- Cancer Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University
| | - Alpha S Yap
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Melissa J Davis
- Bioinformatics Division, Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia
| | - Srikanth Budnar
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
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