Intravenous immunoglobulin (IVIG) preparations induce apoptosis in TNF-alpha-stimulated endothelial cells via a mitochondria-dependent pathway.
Endothelial cells (ECs) are a target in inflammation, and the death of EC is regulated by various factors. Although intravenous immunoglobulin (IVIG) preparations are known to be beneficial therapeutic agents for the treatment of autoimmune diseases and systemic inflammatory disorders, their mechanism of action have not yet been completely elucidated. The aim of the present study is to investigate the possible role of IVIG in EC apoptosis. We demonstrate herein that IVIG induced the apoptosis of human umbilical vein ECs (HUVECs) prestimulated by TNF-alpha in vitro, but not in unstimulated HUVECs, in a dose- and time-dependent manner, using a proportion of cells with hypodiploid DNA, DNA ladder formation and morphological changes. Anti-Fas MoAbs had no effect on the IVIG-induced apoptosis in the TNF-alpha-stimulated HUVECs. IVIG decreased the intracellular expression of anti-apoptotic proteins of the Bcl-2 family (A1 and Bcl-XL) while IVIG increased the intracellular expression of pro-apoptotic proteins (Bax and Bcl-XS) in the TNF-alpha-stimulated HUVECs. Furthermore, IVIG increased the intracellular production of reactive oxygen species and decreased the mitochondrial membrane potential (Delta(psi)m). Caspase-inhibitors inhibited the IVIG-induced apoptosis of the TNF-alpha-stimulated HUVECs. The present results show a novel action in which IVIG can induce the apoptosis of TNF-alpha-stimulated HUVECs through a mitochondrial apoptotic signalling pathway. These observations suggest that the clinical use of IVIG preparations may thereby regulate the cell death of activated ECs in inflammation.
Nakatani
K
K
Department of Paediatrics, National Defense Medical College, Tokorozawa, Saitama, Japan.
Takeshita
S
S
Tsujimoto
H
H
Sekine
I
I
D017209:Apoptosis; D061945:Caspase Inhibitors; D002478:Cells, Cultured; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000494:pharmacology; D007141:Immunoglobulin Fc Fragments / Q000494:pharmacology; D016756:Immunoglobulins, Intravenous / Q000494:pharmacology*; D007700:Kinetics; D008564:Membrane Potentials; D008928:Mitochondria / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019014:fas Receptor / Q000502:physiology
D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D016756:Immunoglobulins, Intravenous; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor