Disruption of the Cytoskeleton After Apoptosis Induction with Autoantibodies

Abstract

F-actin cleavage was studied in PBMC after treatment with anti-dsDNA antibodies. Significant changes in F-actin disruption detected by decrease of FITC-phalloidin staining occurred after apoptosis induction with anti-dsDNA antibodies ( p<0.006). Despite of similar F-actin disruption, the switch of phosphatidylserine (PS) to the outer leaflet of the cell membrane as detected by annexin V binding was lower after anti-dsDNA antibody than without antibody treatment (58.4±11.0% vs. 81.9±7.7%). F-actin disruption was accompanied by activation of caspase 3 within the cytoplasm (r=-0.92599; p<8.87446×10^-10) under both conditions with and without autoantibodies. These findings indicate that anti-dsDNA antibody-induced apoptosis is more marked within the cell than upon the cell surface. The diminished externalization of PS might result in a decreased phagocytosis. Thereby, the reduced clearance of apoptotic cells could induce autoantibody production possibly against epitopes which arise due to the apoptotic disruption of cells.

• Annexin V
• Anti-dsDNA autoantibodies
• Caspase 3
• Phalloidin
• Phosphatidylserine
• F-actin