Mechanotransduction

Scientific basis

Receptors called integrins link the extracellular matrix to the cell's internal skeleton. When the matrix deforms, several relays respond in parallel: adhesion complexes, stretch-sensitive ion channels, cytoskeletal tension, and the connection to the nucleus. They alter gene expression, including that of matrix genes (Ingber, 2003; Chiquet et al., 2009). Cells also sense the stiffness of their environment, notably through the YAP and TAZ factors (Dupont et al., 2011).

Two timescales coexist: in mice, stretch changes the shape of fibroblasts within minutes (Langevin et al., 2005), whereas lasting matrix remodeling takes weeks to months.

The same pathway can support adaptation, with a matrix organized along lines of force, or maladaptation, with myofibroblasts and stiffening, depending on intensity, duration, recovery and the inflammatory context. The sequence of mechanical stress, cellular signal, adaptation or remodeling, then possibly fibrosis, is one possible sequence in certain pathological contexts, not the automatic consequence of a prolonged posture.

Blue Portance / SBNFA™ reading

The SBNFA™ sees mechanotransduction as the link between position and tissue biology: the loads imposed in daily life contribute to what fascia becomes. The hypothesis that variability in mechanical loading alters tissue adaptation processes differently from repeated, low-variability stress belongs to the SBNFA™ reading. The SBNFA™ hypothesizes that alternating loading and recovery helps preserve tissue adaptability.

Contribution to the analysis of sitting

Sitting, repeated for hours every day, is one of the mechanical demands that build up over time. The analysis observes their repetition and their variability; it does not measure any cellular effect.

Not to be confused with

Mechanoreception, the detection of a mechanical stimulus by nerve endings; viscoelasticity, the tissue's immediate mechanical response, without cellular activity; tissue remodeling, a possible lasting consequence of mechanotransduction.

Related terms

Extracellular matrix · Myofibroblast · Fascial stiffness

Sources and scope

• Ingber (2003): tensegrity, cell structure and systems biology (J Cell Sci)
• Chiquet et al. (2009): from mechanotransduction to extracellular matrix gene expression in fibroblasts (Biochim Biophys Acta)
• Dupont et al. (2011): role of YAP/TAZ in mechanotransduction (Nature)
• Langevin et al. (2005): fibroblast cytoskeletal response to subcutaneous tissue stretch (Am J Physiol Cell Physiol)