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Force-induced transcellular tunnel formation in endothelial cells
Win Pin Ng1,2, Kevin D Webster2,3, Caroline Stefani4
1UC Berkeley/UC San Francisco Graduate Group in Bioengineering, Berkeley, California 94720.
Molecular Biology of the Cell
|August 11, 2017
Summary
The actin cytoskeleton acts as a mechanical barrier, resisting transcellular tunnel formation in endothelial cells. Mechanical forces or cytoskeletal disruption can overcome this barrier, facilitating tunnel creation.
Area of Science:
- Cell biology
- Biophysics
- Vascular biology
Background:
- The endothelium forms a semipermeable barrier in blood and lymphatic vessels.
- Transcellular tunnels, formed by endothelial cell membrane fusion, allow leukocyte and pathogen passage.
- The role of the actin cytoskeleton as a barrier to transcellular tunnel formation is not fully understood.
Purpose of the Study:
- To test the hypothesis that the actin cytoskeleton is the primary barrier to transcellular tunnel formation.
- To investigate the mechanical properties of endothelial cells related to transcellular tunnel formation.
Main Methods:
- Utilized atomic force microscopy and fluorescence microscopy on live human umbilical vein endothelial cells (HUVECs).
- Applied localized mechanical forces to induce transcellular tunnel formation.
- Investigated the effects of the bacterial toxin EDIN and a ROCK inhibitor on cytoskeletal properties and tunnel formation.
Main Results:
- Localized mechanical forces are sufficient to induce transcellular tunnels in HUVECs.
- Reduced cytoskeletal stiffness and thickness, observed with EDIN or a ROCK inhibitor, decreased the mechanical work required for tunnel formation.
- Actin enrichment in response to mechanical indentation was diminished in EDIN-treated cells.
Conclusions:
- The actin cytoskeleton provides both passive and active resistance against transcellular tunnel formation in endothelial cells.
- Mechanical force can overcome the actin cytoskeleton's resistance to tunnel formation.
- Disruption of the actin cytoskeleton also facilitates transcellular tunnel formation.
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