In the earliest stages of development, when the tissues are still taking shape, the physical properties of the microenvironment can direct cell differentiation, and initiate the coordinated movement of groups of cells to establish the patterns that will define how the body is arranged. Later, as tissue integrity is impacted by years of use, damage through injury or disease, and subsequent repair mechanisms, the physical properties of the cellular microenvironment will have drastically changed. These changes can lead altered cell behavior, that at times leads to the onset of disease. The importance of the physical microenvironment of cells in development is most prominent in the earliest stages of development, which are collectively referred to as embryogenesis.
Cell-cell signaling refers to inter-cellular communication through the transduction of chemical, mechanical or electrical signals, facilitated by the formation of specialized cell-cell adhesion junctions. There are three main types of cell-cell adhesive junctions in mammals that detect and transduce signals from neighboring cells: tight junctions, adherens junctions, and desmosomes.
Cell polarity refers to the intrinsic asymmetry observed in cells, either in their shape, structure, or organization of cellular components. Most epithelial cells, migrating cells and developing cells require some form of cell polarity for their function. These cells receive information about their surroundings via extracellular biochemical and mechanical cues and translate those information into polarity of the plasma membrane, its associated proteins and cytoskeletal organization. Once established, cell polarity is maintained by transcytosis, in which vesicles carry incorrectly-localized membrane proteins to the correct regions in the plasma membrane. In addition, tight junctions, which act as ‘fences’ against transmembrane diffusion, lock the asymmetry in place. Therefore, mechanobiology plays an essential regulatory role in both the establishment and maintenance of cell polarity.