Experimental tests of the cellular tensegrity hypothesis.

Area of Science:

• Cell Biology
• Biophysics
• Mechanobiology

Background:

• The cytoskeleton (CSK) is a prestressed network crucial for cell structure and function.
• Tensegrity theory posits that cell mechanics are governed by a balance of tension and compression within the CSK.
• A key prediction of tensegrity is the proportional increase of shear modulus (G) with prestress.

Purpose of the Study:

• To test the tensegrity model's prediction that shear modulus (G) increases proportionally with cell prestress.
• To investigate the role of microtubules (MTs) in balancing cell prestress through compression.

Main Methods:

• Airway smooth muscle cells were utilized.
• Traction microscopy measured cell-substrate traction to compute cellular prestress.
• Oscillatory magnetic cytometry determined the cell's shear modulus (G).
• Pharmacological agents (histamine, isoproterenol) and colchicine were used to modulate prestress and disrupt MTs.

Main Results:

• Cellular shear modulus (G) increased in direct proportion to prestress.
• Microtubule compression was found to balance a small but significant fraction of the cell prestress.
• The findings support tensegrity predictions regarding cell mechanics.

Conclusions:

• The study's results align with key predictions of the tensegrity model for cell deformability.
• While not definitively proving tensegrity, the findings support its relevance in explaining fundamental cell mechanics.
• These findings suggest that complex mechanisms may not be required to explain observed cell deformability features under tensegrity principles.