Biophysical profiling of YAP/TAZ dependent mechanical responses

Ageing manifests as architectural alterations at the tissue level and a decline in function. Biochemical and mechanical changes in the extracellular matrix (ECM) during ageing result in decreased cellular mechanotransduction. These changes negatively affect intra- and inter-cellular communication, homeostasis, and regeneration. Remarkably, modifying the aged systemic environment can sometimes reverse aged phenotypes, offering valuable insights into therapeutic interventions for tissue repair and regeneration. Numerous studies have shown that the Hippo pathway, a well-recognized mechanotransductive cellular pathway, and its downstream transcriptional co-activators, YAP and TAZ, play prominent roles in proliferation, regeneration, and wound healing. Interestingly, these are often found to be dysregulated in aged tissue. Yet, the precise mechanisms of YAP/TAZ regulation on cellular responses in an ageing niche remain incompletely understood. Here, the Hippo pathway’s role in coordinating cellular responses to mechanical stimuli was uncovered by utilizing different cellular models, including an isogenic library of HEK293A cells with knockouts of core Hippo pathway components, alongside fibroblasts from spiny mice and mice. Digital holographic microscopy, a label-free quantitative phase imaging technique, was used to measure morphological changes of cells when exposed to mechanical cues resembling the ageing environment, including stiffness, hydrostatic pressure, and ECM substrates. Results indicate that type I collagen sensitizes cells with intact YAP/TAZ regulation to respond to cyclic hydrostatic pressure. Specific collagens increase YAP dephosphorylation and subsequent nuclear translocation and activation. This activation elevates specific TEAD-mediated downstream gene targets involved in the dynamic regulation of cell volume. Meanwhile, cellular responses to stiffness using both elastic supported surface dishes and hydrogel were explored. HEK293A responses to variations in stiffness are also ECM substrate specific. Specific collagen-coated surfaces alter cellular volume, whereas other analysed ECM components mainly affect cell shape. In contrast, spiny mouse fibroblasts are less sensitive to changes in stiffness compared to mouse fibroblasts. This project enhances our understanding of the underlying processes of ageing, highlighting the potential of regulating YAP/TAZ activity to harness regenerative capacity and ultimately promote healthy ageing.

Author dc:creator

• Hui, Ning Sze

Advisors dc:contributor.advisor

• Hansen, Carsten
• Bagnaninchi, Pierre

• YAP/TAZ (Yes-associated protein and transcriptional coactivator with PDZ-binding motif)
• Mechanotransduction
• Extracellular matrix (ECM)
• ECM
• Aging
• Digital holographic microscopy

Language dc:language.iso

en

Identifier URI

https://doi.org/10.7488/era/7419

OAI identifier oai:identifier

oai:era.ed.ac.uk:1842/44904