Extracellular matrix mechanosensing
Cells are dependent on information they receive from each other and from the external environment that they inhabit. This includes the material to which they adhere, which is usually made up of a collection of extracellular molecules secreted by cells, which segregate tissues from one another, provide support and regulate intercellular communication. This material is called extracellular matrix (ECM). Beside the chemical composition, the ECM is characterized by mechanical properties such as stiffness and elastic modulus, which are sensed by cells as the resistance to the force they apply to it.
Cells sense the ECM as they anchor and pull on it. The history of the events starts with the cell’s cytoskeleton which is responsible for all the process involved in sensing the ECM. It is based on nonmuscle myosin II isoforms (NMM IIA, B and C) which contract the cortical actin structures. These actins are connected to focal adhesions molecules such as cadherin, which provide the pathway of force transmission. Then the cellular mechano-transducers, which are focal-adhesion complexes such as integrins send signals from the ECM to the cells. These signals are based on the force needed to deform the matrix .
The stiffness experienced by the cells does not always entirely depend on the elastic modulus of the material out of which is made, the dimensions (such as the thickness) are also important.
Relevance
A better understanding of ECM mechanosensing may have exiting consequences in wound healing and embryogenesis. This may lead to the development of a new wound healing treatment, which will take in consideration the mechanical properties of the wound bed. Exploiting the potential of embryonic stem cells could provide potential ways of using them in regenerative medicine by modulating the mechanical properties on the material they are attached. Nevertheless, a better understanding of ECM role in cell growth and migration will lead to the development of biomaterials for tissue engineering.