  Cells within living soft biological tissues seem to promote the maintenance
of a mechanical state within a defined range near a so-called set-point. This
mechanobiological process is often referred to as mechanical homeostasis.
During this process, cells intimately interact with the fibers of the
surrounding extracellular matrix (ECM). It remains poorly understood, however,
what individual cells actually regulate during these interactions, and how
these micromechanical regulations are translated to tissue level to lead to
what we macroscopically call mechanical homeostasis. Herein, we examine this
question by a combination of experiments, theoretical analysis and
computational modeling. We demonstrate that on short time scales (hours) -
during which deposition and degradation of ECM fibers can largely be neglected
- cells appear to regulate neither the stress / strain in the ECM nor their own
shape, but rather only the contractile forces that they exert on the
surrounding ECM.
