Targeting of tumor necrosis factor receptor 1 to low density plasma membrane domains in human endothelial cells.

TNFR1 (tumor necrosis factor receptor 1) localizes to caveolae of human endothelial-derived EA.hy926 cells. Transduced TNFR1 molecules lacking amino acid residues 229-244 (spanning the transmembrane/intercellular boundary) are expressed on the cell surface equivalently to full-length TNFR1 molecules but incompletely localize to caveolae.

Lipopolysaccharide can trigger a cathepsin B-dependent programmed death response in human endothelial cells.

In this study, we examined the mechanisms that contribute to lipopolysaccharide (LPS)-induced death responses in cultured human umbilical vein endothelial cells (HUVECs). In the presence of the protein synthesis inhibitor cycloheximide, LPS primarily induces caspase-dependent apoptotic cell death of HUVECs, which is blocked by siRNA-mediated knockdown of myeloid differentiation factor 88 adaptor protein but not of Toll-like receptor-associated interferon-inducing factor. Knockdown of Fas-associated death domain protein (FADD) by either siRNA or overexpression of a truncated version of FADD that lacks the N-terminal death effector domain (FADD(DN)) increases the sensitivity of HUVECs to LPS plus cycloheximide-mediated death.

Interferon-gamma induces X-linked inhibitor of apoptosis-associated factor-1 and Noxa expression and potentiates human vascular smooth muscle cell apoptosis by STAT3 activation.

Interferon (IFN)-gamma actions on the vessel wall play an important role in the pathogenesis of arteriosclerosis, yet the contribution of different IFN-gamma signaling pathways to the phenotypic modulation of vascular smooth muscle cells (VSMCs) are poorly understood. We investigated the effects of IFN-gamma on VSMCs and arteries through interactions involving signal transducer and activator of transcription (STAT) proteins. In addition to STAT1 activation, IFN-gamma consistently phosphorylated STAT3 in human VSMCs but weakly or not at all in human endothelial cells or mouse VSMCs.

The cathepsin B death pathway contributes to TNF plus IFN-gamma-mediated human endothelial injury.

Vascular endothelial cells are primary targets of cytokine-induced cell death leading to tissue injury. We previously reported that TNF in combination with LY294002, a PI3K inhibitor, activates caspase-independent cell death initiated by cathepsin B (Cat B) in HUVEC. We report that TNF in the presence of IFN-gamma activates Cat B as well as a caspase death pathway in both HUVEC and human dermal microvascular endothelial cells, but only activates caspase-mediated death in HeLa cells and human embryonic kidney (HEK)293 cells.

TRAIL induces apoptosis and inflammatory gene expression in human endothelial cells.

Human TRAIL can efficiently kill tumor cells in vitro and kill human tumor xenografts in mice with little effect on normal mouse cells or tissues. The effects of TRAIL on normal human tissues have not been described. In this study, we report that endothelial cells (EC), isolated from human umbilical veins or human dermal microvessels, express death domain-containing TRAIL-R1 and -R2.

Interferon-gamma augments CD95(APO-1/Fas) and pro-caspase-8 expression and sensitizes human vascular endothelial cells to CD95-mediated apoptosis.

We have examined the effects of interferon (IFN)-gamma on expression and function of CD95 (APO-1/Fas) and associated proteins in cultured human umbilical vein and dermal microvascular endothelial cells (HUVEC and HDMEC, respectively). Unstimulated cells express only low levels of CD95; IFN-gamma produces a time- and concentration-dependent increase of CD95 in both cell types at the mRNA and cell surface protein levels. IFN-gamma also produces an increase in expression of pro-caspase-8 (FLICE/MACH) but does not significantly change expression of either Fas-associated death domain (FADD) protein or cellular FLICE inhibitory protein (cFLIP), other proteins associated with the CD95 death-inducing signaling complex (DISC).