Protocol for quantitative analysis of pulsatile contractions and cell extrusion in epithelial tissues of larval zebrafish

Atieh, Youmna; Ruíz, Óscar E.; Eisenhoffer, George T.

doi:10.1016/j.xpro.2021.100600

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…4dpf larvae were treated with 10mM metronidazole (MTZ) for 2-4 hours in a 28.5°C incubator to induce extrusion activity, as described in (Atieh et al, 2021a; Atieh et al, 2021b).…”

Section: Methodsmentioning

confidence: 99%

Assessing mechanical agency during apical apoptotic cell extrusion

Anjum,

Turner,

Atieh

et al. 2023

Preprint

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Epithelial tissues maintain homeostasis through the continual addition and removal of cells. Homeostasis is necessary for epithelia to maintain barrier function and prevent the accumulation of defective cells. Unfit, excess, and dying cells can be removed from epithelia by the process of extrusion. Controlled cell death and extrusion in the epithelium of the larval zebrafish tail fin coincides with oscillation of cell area, both in the extruding cell and its neighbors. Both cell-autonomous and non-autonomous factors have been proposed to contribute to extrusion but have been challenging to test by experimental approaches. Here we develop a dynamic cell-based biophysical model that recapitulates the process of oscillatory cell extrusion to test and compare the relative contributions of these factors. Our model incorporates the mechanical properties of individual epithelial cells in a two-dimensional simulation as repelling active particles. The area of cells destined to extrude oscillates with varying durations or amplitudes, decreasing their mechanical contribution to the epithelium and surrendering their space to surrounding cells. Quantitative variations in cell shape and size during extrusion are visualized by a hybrid weighted Voronoi tessellation technique that renders individual cell mechanical properties directly into an epithelial sheet. To explore the role of autonomous and non-autonomous mechanics, we vary the biophysical properties and behaviors of extruding cells and neighbors such as the period and amplitude of repulsive forces, cell density, and tissue viscosity. Our data suggest that cell autonomous processes are major contributors to the dynamics of extrusion, with the mechanical microenvironment providing a less pronounced contribution. Our computational model based on in vivo data serves as a tool to provide insights into the cellular dynamics and localized changes in mechanics that promote elimination of unwanted cells from epithelia during homeostatic tissue maintenance.

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“…4dpf larvae were treated with 10mM metronidazole (MTZ) for 2-4 hours in a 28.5°C incubator to induce extrusion activity, as described in (Atieh et al, 2021a; Atieh et al, 2021b).…”

Section: Methodsmentioning

confidence: 99%

Assessing mechanical agency during apical apoptotic cell extrusion

Anjum,

Turner,

Atieh

et al. 2023

Preprint

Self Cite

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“…In one set of changes, hypercontractility of apoptotic cells stimulates the adjacent cells to assemble a contractile cortex at their interface with the apoptotic cells ( Andrade and Rosenblatt, 2011 ; Lubkov and Bar-Sagi, 2014 ; Duszyc et al. , 2021a ; Atieh et al. , 2021 ).…”

Section: Introductionmentioning

confidence: 99%

Preexisting tissue mechanical hypertension at adherens junctions disrupts apoptotic extrusion in epithelia

Mann,

Lim,

Verma

et al. 2024

MBoC

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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 neighbours, as well as local changes in tissue mechanics. Here we report that the pre-existing mechanical tension at adherens junctions 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 pro-inflammatory 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 co-opted by pathogenetic factors to disrupt the homeostatic response of epithelia to apoptosis.

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“…Successful extrusion involves a complex series of mechanical changes in the apoptotic cells and their proximal neighbours (Fig S1A) (Teo, Tomatis, et al 2020). In one set of changes, hypercontractility of apoptotic cells stimulates the adjacent cells to assemble a contractile cortex at their interface with the apoptotic cells (Andrade and Rosenblatt 2011; Atieh, Ruiz, and Eisenhoffer 2021; Duszyc, Gomez, et al 2021; Lubkov and Bar-Sagi 2014). Contraction of this cortical network drives the physical expulsion of the dying cells.…”

Section: Introductionmentioning

confidence: 99%

Pre-existing tissue mechanical hypertension at adherens junctions disrupts apoptotic extrusion in epithelia

Mann,

Lim,

Verma

et al. 2023

Preprint

View full text Add to dashboard Cite

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 neighbours, as well as local changes in tissue mechanics. Here we report that the pre-existing mechanical tension at adherens junctions 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 pro-inflammatory cytokine, TNFa, 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 TNFa-treated monolayers. Together, these findings demonstrate that baseline levels of tissue tension are important determinants of apoptotic extrusion, which can potentially be co-opted by pathogenetic factors to disrupt the homeostatic response of epithelia to apoptosis.

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Protocol for quantitative analysis of pulsatile contractions and cell extrusion in epithelial tissues of larval zebrafish

Cited by 4 publications

References 10 publications

Assessing mechanical agency during apical apoptotic cell extrusion

Assessing mechanical agency during apical apoptotic cell extrusion

Preexisting tissue mechanical hypertension at adherens junctions disrupts apoptotic extrusion in epithelia

Pre-existing tissue mechanical hypertension at adherens junctions disrupts apoptotic extrusion in epithelia

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