Cytoskeletal changes of mesenchymal stem cells during differentiation

Area of Science:

• Biophysics
• Cell Biology
• Tissue Engineering

Background:

• Mesenchymal stem cells (MSCs) are multipotent stromal cells crucial for bone and cartilage regeneration.
• Understanding the mechanical properties and cytoskeletal dynamics of MSCs during differentiation is vital for regenerative medicine.

Purpose of the Study:

• To investigate the role of the actin cytoskeleton in the nanomechanics of human mesenchymal stem cells (hMSCs) and their differentiated progeny.
• To assess the impact of cytoskeletal disruption and recovery on cell mechanics in hMSCs, chondrocytes, and osteoblasts.

Main Methods:

• Utilized fluorescence microscopy to visualize cytoskeletal organization.
• Employed atomic force microscopy (AFM) for quantitative nanomechanical measurements (Young's Modulus) and force-volume imaging.
• Applied Cytochalasin D (CytD) to reversibly disrupt the actin cytoskeleton in various cell types.

Main Results:

• Actin cytoskeleton disruption with CytD showed dose-dependent effects and was reversible.
• hMSCs and hMSC-chondrocytes exhibited more significant cytoskeletal changes and nanomechanical alterations (decreased Young's Modulus) compared to hMSC-osteoblasts.
• CytD treatment induced morphological changes across all cell types studied.

Conclusions:

• Human mesenchymal stem cells dynamically alter their cytoskeletal components and mechanical properties during differentiation into chondrocytes and osteoblasts.
• Osteoblasts appear to possess a more stable cytoskeleton compared to undifferentiated MSCs and chondrocytes.
• These findings provide insights into cell mechanobiology relevant to tissue engineering and regenerative medicine.