Nanoporosity Stimulates Cell Spreading and Focal Adhesion Formation in Cells with Mutated Paxillin

Area of Science:

• Biomaterials Science
• Cell Biology
• Surface Engineering

Background:

• Cellular response to nanotopography is crucial for biomaterial design.
• Paxillin phosphorylation at serine 273 influences cell-surface biomechanics.
• Understanding genetic mutation effects on cell-material interactions is key.

Purpose of the Study:

• To evaluate the response of CHO-K1 cells with wild-type and mutated paxillin to nanotopography.
• To investigate how surface nanoporosity affects cell adhesion, spreading, and cytoskeletal organization.
• To determine if nanotopography can compensate for genetic defects in cell-surface interactions.

Main Methods:

• Culturing CHO-K1 cells (wild-type and S273 mutant paxillin) on nanoporous and polished titanium surfaces.
• Immunofluorescence microscopy to assess cell adhesion, spreading, and actin filament organization.
• Scanning electron microscopy to visualize cell morphology and filopodia.
• Gene expression analysis of proteins involved in cell adhesion and protrusions.

Main Results:

• Nanotopography minimally affected cell adhesion and spreading but increased actin filament abundance and alignment.
• Scanning electron microscopy revealed altered cell shape and abundant filopodia with nanoprotrusions on nanoporous surfaces.
• Gene expression analysis showed significant upregulation of adhesion and protrusion proteins on nanoporous surfaces.
• Specific proteins (α-actinin, Rac1, Cdc42, ITGα1) were upregulated, while others (FAK, Pxn, Src) were downregulated in S273 mutant cells, enhancing focal adhesion.

Conclusions:

• Surface nanoporosity significantly influences cell morphology, cytoskeletal organization, and gene expression.
• Nanotopography can compensate for genetic mutations affecting cell-surface biomechanical relationships.
• This suggests potential for designing biomaterials that mitigate the effects of genetic defects on cellular behavior.