Potential Hydrodynamic Cytoplasmic Transfer between Mammalian Cells: Cell-Projection Pumping

Area of Science:

• Cell Biology
• Biophysics

Background:

• Intercellular cytoplasmic transfer influences cell phenotype.
• Previous studies suggested transfer via tunneling nanotubes or shed vesicles.

Purpose of the Study:

• Investigate the mechanism of cytoplasmic fluorescence exchange between human fibroblasts (Fibs) and malignant cells (MCs).
• Propose and validate a novel mechanism termed cell-projection pumping (CPP).

Main Methods:

• Time-lapse microscopy to observe cytoplasmic exchange.
• Holotomography to visualize fine cell projections.
• Atomic force microscopy to measure cell stiffness.
• Mathematical modeling and computer simulations to test the CPP hypothesis.

Main Results:

• Cytoplasmic transfer predominantly occurred from Fibs to MCs.
• Transfer was mediated by fine, rapidly retracting cell projections, not tunneling nanotubes or vesicles.
• Cell stiffness influenced the direction and extent of cytoplasmic transfer.
• Mathematical modeling and simulations supported the CPP mechanism, predicting preferential transfer into less stiff cells.

Conclusions:

• Cell-projection pumping (CPP) is proposed as a novel mechanism for mammalian intercellular cytoplasmic transfer.
• CPP involves hydrodynamic forces during cell projection retraction and microfusion events.
• The findings highlight the role of biophysical properties like cell stiffness in regulating intercellular communication.