HMGB1 release in co-cultures of porcine endothelial and human T cells.
High mobility group box-1 (HMGB1) protein, primarily from the nucleus, is released into the extracellular milieu either passively by necrotic or damaged cells, or actively by secretion from monocytes/macrophages. Extracellular HMGB1 acts as a potent inflammatory stimulator by promoting cytokine (for example, tumor necrosis factor-alpha) production, and also has pro-coagulant activity. The signaling pathway initiated by receptor for advanced glycation end-product (RAGE), which is the HMGB1 receptor, also induces complement activation. Recent studies have implicated HMGB1 in acute cardiac allograft rejection, and have identified infiltrating T cells and other damaged cells as its main sources. HMGB1 blockade using the anti-HMGB1 antibody HMGB1 box-A (amino-terminal region) and soluble RAGE rescues mice from acute rejection. We therefore studied the release of HMGB1 in co-cultures of porcine aortic endothelial cells (PAEC) and human leukocytes. Human T cells, but not B cells, monocytes or neutrophils, stimulated significant HMGB1 release in culture with PAEC; this activity required cell-cell contact and was dose-dependent, as determined by Western blotting. The released HMGB1 originated from both cell types, as immunofluorescent microscopy showed that it was present in the cytosol of PAEC in contact with T cells, and had disappeared from the T-cell nuclei. These results demonstrate that direct interactions between PAEC and T cells might be a key factor in triggering HMGB1 release, which suggests that HMGB1 is associated with graft rejection in the early phase.
Kawahara
Ko-ichi
K
Department of Laboratory and Vascular Medicine, Cardiovascular and Respiratory Disorders Advanced Therapeutics, Kagoshima University Graduate School of Medical and Dental Science, Kagoshima, Japan.
Setoyama
Kentaro
K
Kikuchi
Kiyoshi
K
Biswas
Kamal Krishna
KK
Kamimura
Ryozo
R
Iwata
Masahiro
M
Ito
Takashi
T
Morimoto
Yoko
Y
Hashiguchi
Teruto
T
Takao
Sonshin
S
Maruyama
Ikuro
I
D000818:Animals; D017252:CD3 Complex / Q000032:analysis; D018920:Coculture Techniques; D016207:Cytokines / Q000502:physiology; D004730:Endothelium, Vascular / Q000378:metabolism*; D006084:Graft Rejection / Q000503:physiopathology; D024243:HMGB1 Protein / Q000378:metabolism*; D006801:Humans; D007249:Inflammation; D007962:Leukocytes / Q000378:metabolism; D013552:Swine; D013601:T-Lymphocytes / Q000378:metabolism*; D014183:Transplantation, Heterologous / Q000276:immunology
D017252:CD3 Complex; D016207:Cytokines; D024243:HMGB1 Protein