Disrupted Stiffness Ratio Alters Nuclear Mechanosensing

Area of Science:

• Cell biology
• Biophysics
• Cardiovascular research

Background:

• Endothelial cells are crucial for vascular homeostasis, sensing blood flow dynamics.
• Mechanotransduction, the process by which cells sense mechanical stimuli, is vital for cardiovascular health.
• Nuclear and cytoplasmic properties influence cellular mechanosensory responses.

Purpose of the Study:

• To investigate how mechanical properties of endothelial cell compartments affect mechanotransduction.
• To determine the role of nuclear and cytoplasmic stiffness in shear stress transfer.
• To explore the impact of cellular aging on these mechanosensory mechanisms.

Main Methods:

• Utilized atomic force microscopy to measure mechanical properties.
• Employed mathematical modeling and computational studies to analyze shear stress transfer.
• Compared replicatively aged cells with a genetic model of accelerated aging.

Main Results:

• The stiffness ratio between nuclear and cytoplasmic compartments, not individual stiffness, critically controls shear stress transfer.
• Replicatively aged endothelial cells exhibited a reduced stiffness ratio, leading to attenuated shear stress transfer.
• A genetic model of accelerated aging did not show altered stiffness ratios.

Conclusions:

• Relative mechanical changes in subcellular compartments can uniquely impair the shear stress response.
• Dysregulation of mechanotransduction due to altered stiffness ratios may contribute to age-related cardiovascular dysfunction.
• Findings provide a theoretical framework for understanding mechanosensory consequences of altered cellular mechanics.