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Mechanobiology of Disease
Poster Abstracts
50
19-POS
Board 19
Spatial Mechanical Heterogeneity in Epithelial Cell Sheet : An Atomic Force Microscopy
Study
Yuki Fujii
, Takaharu Okajima.
Hokkaido University, Sapporo, Japan.
In epithelial sheet, cells are tightly packed and connect the neighboring cells through cell
junctions. These cells interact mechanically and migrate collectively by exerting tensile forces
between cells and on extracellular matrix [1]. However, it is little known how the cell stiffness is
regulated through the cell-cell mechanical interactions. In this study, we investigate the spatial
distribution of the elastic modulus of epithelial Mardin-Darby canine kidney (MDCK) cell sheet
in a large region by atomic force microscopy (AFM). MDCK cell sheet sample is prepared
confluent condition. The AFM force curve measurements were used to map the spatial
distribution of MDCK cells.
We observed that the elastic modulus of MDCK cell sheet exhibits a characteristic spatial
correlation length that is much longer than the distance between neighboring cells. This means
that the elastic modulus of cell increases as the surrounding cells are stiffer whereas the elastic
modulus decreases as the surrounding cells are softer. The magnitude of the elastic modulus was
drastically reduced as actin filaments were depolymerized, and the spatial correlation of the cell
elastic modulus was disappeared by disrupting actin filaments. Moreover, the reduction of the
spatial correlation length was clearly observed as E-cadherin-dependent cell-cell adhesion was
inhibited by EGTA. Interestingly, the spatial correlation length of the MDCK cells was
recovered to that in the control condition as E-cadherin junctions between cells were again
stabilized by washing out EGTA. The results suggest that the elastic modulus of epithelial cell
sheet sensitively changes depending on the elastic modulus of the surrounding cells and the
regulation of the cell elastic modulus is directly driven through the cell junctions.
[1] E, Bazallieres., et al., Nature cell boil 17, 409-420 (2015).