Skewness of the height distribution in cell topography images is a measure of cell shape

Abstract

The regulation of cell shape is crucial for the functioning of living cells. To analyze cell function, it is therefore important to quantify cell shape. We present an approach for the quantification of vertical cell shape that is based on a statistical analysis of height distributions in topography images such as obtained by scanning probe microscopy. Using scanning ion conductance microscopy (SICM), we found that induced cytoskeletal alterations led to a change from a dome-like toward a fried-egg-like vertical cell shape. This shape change affected a cell’s height distribution and the symmetry of this distribution. We used the third central moment of the distribution, the skewness, as a statistical measure of the distribution’s symmetry and therefore of vertical cell shape. This approach provides an unbiased and fast method for the analysis of vertical cell shape and works even for confluent cell layers.