Biomedical Engineering Reference
In-Depth Information
Fig. 1.1
Steps involved in cell migration (Okeyo et al.
2010
). (
a
) Illustration of major processes
that occur during cell migration.
Green arrow
indicates protrusion;
purple arrow
indicates adhe-
sion, and
navy blue arrow
indicates retraction. (
b
) Polarized fi sh keratocytes undergoing rapid
locomotion on a glass substrate. (
c
) Phase contrast image of a migrating keratocyte with outlines
of successive frames to illustrate the steady and persistent movement of the cell.
White arrow
indicates the direction of cell movement (Adapted with permission from JSME: [Journal of
Biomechanical Science and Engineering], copyright (2012))
In the third step, mechanical forces (contractile forces) resulting from the
interaction between actin and myosin II disassemble FAs to enable retraction of the
rear and forward translocation of the cell body. Protrusion and retraction are highly
coordinated in rapidly migrating cells such as epidermal fi sh keratocytes shown in
Fig.
1.1c
, resulting in persistent migration along a given direction.
In addition to contractile forces, a migrating cell interacts with the extracellular
matrix (ECM, or simply, substrate) via FAs, resulting in the development of traction
forces. Furthermore, a migrating cell is subjected to additional other mechanical
forces emanating from its biomechanical environment, including substrate rigidity,
shear stress due to fl uid fl ow (e.g. endothelial cells are exposed to shear stress due
to blood fl ow), hydrostatic and compressive forces (Li et al.
2005
). Cells maintain
homeostasis by sensing and converting these biomechanical signals into biological
functions via mechanotransduction (Chen
2008
).
