Thrombin-induced contraction in alveolar epithelial cells probed by traction microscopy
Núria Gavara1, Raimon Sunyer, Pere Roca-Cusachs
1Unitat de Biofísica i Bioenginyeria, Facultat de Medicina-Universitat de Barcelona, Casanova 143, 08036 Barcelona, Spain.
Summary
Thrombin significantly increases contractile forces in alveolar epithelial cells by remodeling the actin cytoskeleton. This response, mediated by myosin light chain kinase and Rho kinase, may compromise lung barrier integrity.
Area of Science:
- Cellular biology
- Pulmonary medicine
- Biophysics
Background:
- Alveolar epithelial cells are crucial for maintaining lung structural integrity.
- Contractile forces within these cells influence the alveolar barrier's force balance.
- Understanding these forces is key to addressing lung injury.
Purpose of the Study:
- To investigate thrombin-induced contractile forces in alveolar epithelial cells.
- To elucidate the cellular mechanisms underlying thrombin's effect on cell contraction.
- To assess the potential impact on alveolar barrier function.
Main Methods:
- Utilized A549 alveolar epithelial cells.
- Measured contractile forces using traction microscopy.
- Analyzed actin cytoskeleton dynamics via fluorescent staining.
- Investigated signaling pathways using specific inhibitors (cytochalasin D, ML-7, Y-27632).
Main Results:
- Cells exhibited basal contractile forces (55.0 +/- 12.0 nN) at the periphery.
- Thrombin (1 U/ml) induced a 2.5-fold sustained increase in contractile forces.
- Observed F-actin polymerization and enhanced peripheral actin rim.
- Actin cytoskeleton disruption and pathway inhibition abolished thrombin-induced contraction.
Conclusions:
- Thrombin triggers alveolar epithelial cell contraction via actin cytoskeleton remodeling.
- Actomyosin activation through myosin light chain kinase and Rho kinase mediates this response.
- Thrombin-induced contractile tension may impair alveolar epithelial barrier integrity in injured lungs.
