Influence of surface charges on cell adhesion: difference between static and dynamic conditions

Area of Science:

• Biophysics
• Cell Biology
• Immunology

Background:

• Cell adhesion is crucial for immune responses and tissue function.
• Understanding factors influencing cell adhesion under different conditions is vital.
• Nonspecific repulsion, including electrostatic and steric effects, can modulate cell interactions.

Purpose of the Study:

• To investigate whether nonspecific repulsion more efficiently impairs cell adhesion under dynamic versus static conditions.
• To determine the impact of neuraminidase treatment on cell adhesion under flow.
• To explore the relationship between adhesion molecule properties and binding efficiency.

Main Methods:

• Human monocytic THP1 cells were used, plated on glass surfaces.
• Adhesion was quantified using spherical particles with monoclonal antibodies targeting specific cell antigens (CD11b, CD18, CD35, CD64).
• Adhesion was measured in a flow chamber under low shear rates (11 or 22 s-1) after neuraminidase treatment.

Main Results:

• Neuraminidase treatment had minimal effect on static adhesion, except for a significant increase in CD18-mediated interaction at 4°C.
• Under dynamic (flow) conditions, neuraminidase treatment substantially enhanced cell binding.
• No clear correlation was observed between the length of adhesion molecules and binding efficiency.
• Cell shape and the topographical distribution of adhesion molecules significantly influenced adhesion under flow.

Conclusions:

• Dynamic reorganization of the pericellular matrix plays a key role in regulating cell adhesion.
• Nonspecific repulsion effects are more pronounced under dynamic flow conditions.
• Factors beyond simple molecular length, such as cell morphology and molecule distribution, are critical for adhesion regulation.