Nuclei deformation reveals pressure distributions in 3D cell clusters

Area of Science:

• Cellular and Molecular Mechanobiology
• Biophysics
• Biomaterials

Background:

• Quantifying mechanical forces within multicellular environments is crucial for understanding mechanobiology.
• Existing methods for measuring internal cellular pressure are often limited by the need for invasive or poorly calibrated probes.

Purpose of the Study:

• To develop and validate a novel technique for measuring intracellular pressure in 3D multicellular aggregates using endogenous cell nuclei as biosensors.
• To quantify the mechanical stresses within multicellular structures and investigate their relationship with cluster geometry and cell number.

Main Methods:

• Utilized a fluorescent protein localized to the nucleus to measure nuclear volume via confocal microscopy in 3D multicellular aggregates.
• Calibrated nuclear volume changes to pressure by quantifying responses to osmotic pressure in 2D cultures.
• Analyzed nuclear volume and inferred pressure distribution in spherical and oblong cell clusters.

Main Results:

• Nuclear compressive mechanical stresses in multicellular structures are on the order of MPa.
• These stresses increase with the number of cells within a cluster.
• Stress distribution is homogenous in spherical clusters but asymmetric in oblong clusters.

Conclusions:

• Endogenous cell nuclei can serve as effective pressure sensors in multicellular environments.
• The developed technique provides quantitative mechanical measurements in complex biological structures.
• This approach has potential applications for in vitro and in vivo studies of mechanobiology.