Blocking of pathogenic anti-Dsg3 antibody-induced increase in keratinocyte stiffness by caspase inhibition, but not Fas ligand neutralization.

<p>HaCaT keratinocytes were grown to confluence and cell stiffness was measured by AFM (expressed as percent of cells measured at a given Young’s Modulus). Cell stiffness distribution in (<b>A</b>) untreated cells (Gaussian fit with peaks around 32.0 kPa and 75.2 kPa), (<b>B</b>) cells treated with the pathogenic anti-Dsg3 antibody Px4-3 (10 µg/ml) alone for 8 h (peaks around 34.8 kPa and 83.5 kPa), (<b>C</b>) cells pretreated with caspase inhibitor (20 µM) 30 min before addition of pathogenic antibody (single peak around 17.7 kPa), (<b>D</b>) cells pretreated with Fas ligand neutralizing antibody (0.5 µg/ml) 30 min before addition of pathogenic antibody (peaks around 29.1 kPa and 73.0 kPa), (<b>E</b>) treated with caspase inhibitor (20 µM) alone for 8.5 h (single peak 30.1 kPa), or (<b>F</b>) treated with Fas ligand neutralizing antibody (0.5 µg/ml) alone for 8.5 h (single peak 32.3 kPa. The single peak of cells of low stiffness observed for treatment with caspase inhibitor (<b>E</b>) and FasL neutralizing antibody (<b>F</b>) alone indicates that the spontaneous apoptosis seen in untreated cells can be completely abrogated by these two blockers.