Roles of Cell Junctions and the Cytoskeleton in Substrate-free Cell Sheet Engineering

In multicellular organisms, one-cell-thick monolayer sheets are the simplest tissues, yet they play crucial roles in physiology and tissue engineering. Cells within these sheets are tightly connected to each other through specialized cell-adhesion molecules that typically cluster into in discrete patches called cell-cell junctions. Working together, these junctional organelles glue cells to their neighbors and integrate the cytoskeletons into a mechanical syncytium. Human bodies offer many vivid illustration of how a cell sheet physiology changes considerably during development and diseases, as shown in epidermal blistering and certain cardiomyopathy, which requires it to be mechanically durable and capable of transducing a variety of mechanical signals. Despite the extensive molecular and clinical work on cell junctions, relevant in vitro experimental data are often masked by cell-substrate interactions due to a lack of suitable experimental methods. It is therefore important to develop novel in vitro methods for characterizing how junctional proteins, as well as tightly associated cytoskeletal proteins, may modulate various cellular behaviors, such as viability and apoptosis, cell-cell adhesiveness and tissue integrity. Control over cell viability is a fundamental property underlying numerous physiologica