Stress vesicles link epidermal mechanotransduction to stem cell differentiation

Area of Science:

• Dermatology
• Cell Biology
• Biophysics

Background:

• Skin exhibits remarkable plasticity to adapt to mechanical stimuli.
• Sustained mechanical stress leads to lasting changes in skin tissue structure.
• The role of epidermal stem cell fate in response to mechanical stress is not fully understood.

Purpose of the Study:

• To investigate if epidermal stem cell fate mediates skin's response to mechanical stress.
• To identify the cellular mechanisms linking mechanical forces to stem cell fate.
• To explore the role of calcium signaling and mechanosensitive channels in this process.

Main Methods:

• Two-photon intravital imaging of epidermal cells in live skin under mechanical force.
• Lineage tracing analyses to correlate nuclear deformation with cell fate.
• Conditional deletion of the Piezo1 ion channel to assess its role in calcium dynamics and stress vesicle formation.
• Human skin xenografts to confirm stress vesicle conservation.

Main Results:

• Mechanical force induces intracellular "stress" vesicles in epidermal stem cells, deforming the nucleus.
• The degree of nuclear deformation predicts stem cell fate outcomes.
• Mechanical stress causes sustained elevation of intracellular calcium.
• Piezo1 channel deletion disrupts calcium dynamics and increases stress vesicle formation.
• Stress vesicles are conserved in mammalian skin.

Conclusions:

• Stress vesicles are key mediators linking mechanical stress, calcium signaling, and epidermal stem cell fate.
• These findings provide insights into skin's adaptive responses to mechanical environments.
• The study identifies a novel mechanism for how skin stem cells respond to physical forces.