Electromechanics and Volume Dynamics in Nonexcitable Tissue Cells

Area of Science:

• Cell Biology
• Biophysics

Background:

• Cell volume regulation is critical for cellular processes like growth, proliferation, and tissue homeostasis.
• The precise mechanisms controlling cell size over a lifetime remain incompletely understood.

Purpose of the Study:

• To investigate the coupling between nonexcitable tissue cell volume, membrane electrical potential, and extracellular ion concentrations.
• To model water dynamics influenced by membrane potential and permeable ion concentrations.

Main Methods:

• Utilized whole-cell patch clamp electrophysiology to induce cell depolarization and hyperpolarization.
• Manipulated extracellular concentrations of chloride, sodium, potassium, and observed effects on cell volume.
• Investigated the role of cortical tension by inducing actin depolymerization.
• Developed an electrophysiology model for water dynamics.

Main Results:

• Cell depolarization led to a significant ~50% increase in cell volume; hyperpolarization caused a slight decrease.
• Modulating extracellular chloride or sodium/potassium concentrations altered cell volume.
• Depleting external chloride reduced cell volume; high-potassium solutions increased volume up to 50%.
• Actin depolymerization resulted in cell volume increase.

Conclusions:

• Cell volume is directly coupled to membrane electrical potential and extracellular permeable ion concentrations.
• The developed model quantitatively predicts cell volume is proportional to intracellular protein content.