Electrical and ionic controls of tissue cell locomotion in DC electric fields

Area of Science:

• Cell Biology
• Biophysics
• Electrophysiology

Background:

• Fish epidermal cells, known as keratocytes, exhibit remarkable motility.
• Cellular responses to external electric fields are not fully understood.
• Cytoskeletal dynamics, particularly actomyosin networks, are vital for cell movement.

Purpose of the Study:

• To investigate the effect of direct current (DC) electric fields on fish keratocyte motility.
• To elucidate the role of calcium influx and cytoskeletal components in electric field-guided cell migration.
• To explore the mechanisms by which electric fields influence transmembrane ion fluxes and cell locomotion.

Main Methods:

• Observation of keratocyte migration in DC electric fields (0.5-15 V/cm).
• Assessment of cell morphology, lamellipodia extension, and cell-cell interactions under electric fields.
• Pharmacological manipulation using calcium channel antagonists.
• Testing the effects of altered membrane potential (hyperpolarizing and depolarizing media).
• Investigating the impact of microtubule disassembly on cell behavior.

Main Results:

• Keratocytes, cell clusters, and sheets migrate cathodally in DC electric fields.
• Higher field strengths (upper range) induced dissociation of cell clusters and sheets into single cells.
• Lamellipodial extension and locomotion were reversibly inhibited by calcium channel antagonists.
• Cell motility was unaffected by changes in membrane potential (low/high K+ media).
• Microtubule disassembly did not alter cell morphology, motility, or electric field guidance.

Conclusions:

• Membrane-regulated calcium (Ca2+) influx plays a significant role in generating cytoskeletal and protrusive activity in keratocytes.
• External electric fields may control cell locomotion by influencing transmembrane ion fluxes.
• DC electric fields provide a tool to study ion flux-dependent cellular processes and motility.