Fitc-AEVD-FMK

Background:Microvascular hyperpermeability that occurs in hemorrhagic shock and burn trauma is regulated by the apoptotic signaling pathway. We hypothesized that tumor necrosis factor-α (TNF-α)-related apoptosis-inducing ligand (TRAIL) would promote hyperpermeability directly or by interacting with other signaling pathways.Methods:Rat lung microvascular endothelial cells (RLMECs) grown on Transwell membranes (Corning Life Sciences, Lowell, MA) were treated with recombinant human TRAIL (10, 50, and 100 ng/mL) for 6 hours or TRAIL (100 ng/mL) + LY294002 (a PI3K inhibitor; 20 μmol/L), Z-DEVD-FMK (a caspase-3 inhibitor; 10 μmol/L), or the inhibitors alone. Fluorescein isothiocyanate (FITC)-albumin flux was an indicator of permeability. Caspase-3 activity was measured fluorometrically. Adherens junction integrity was studied using β-catenin immunofluorescence.Results:TRAIL + LY294002, but not TRAIL alone, induced monolayer hyperpermeability (P < .05), and caspase-3 activity (P < .05), and disrupted the adherens junctions. Z-DEVD-FMK attenuated hyperpermeability and protected the adherens junctions.Conclusions:TRAIL-induced microvascular hyperpermeability is phosphatidylinositol 3-kinase (PI3K)-dependent and may be mediated by caspase-3 cleavage of the endothelial adherens junctional complex.

Ziram as a dithiocarbamate fungicide is widely used throughout the world in agriculture and as an accelerating agent is used in latex production. In order to investigate ziram-induced apoptosis/necrosis and its underlying mechanism in human immune cells, a human monocyte-like cell line (U937) was treated with ziram at 0.0312-2 μM for 2-24 h at 37 °C in a 5% CO₂ incubator. Apoptosis/necrosis induced by ziram was determined by analysis of FITC-Annexin-V/PI staining and the intracellular level of active caspase-3 by flow cytometry and DNA fragmentation analysis. We found that ziram induced apoptosis/necrosis in U937 in a time- and dose-dependent manner, as shown by FITC-Annexin-V/PI staining. DNA fragmentation was detected when cells were treated with 0.5, 1, or 2 μM ziram for 24 h. Ziram also induced an increase in intracellular active caspase-3 in U937 cells in a dose-dependent manner, and a caspase-3 inhibitor, Z-DEVD-FMK, significantly inhibited the ziram-induced apoptosis. Moreover, it was found that ziram induced mitochondrial cytochrome c release in U937 cells. These findings indicate that ziram can induce apoptosis/necrosis in U937 cells, and this effect is partially mediated by activation of intracellular caspase-3 and mitochondrial cytochrome c release.

Tumor necrosis factor-α (TNF-α), a pro-apoptotic cytokine, is involved in vascular hyperpermeability, tissue edema, and inflammation. We hypothesized that TNF-α induces microvascular hyperpermeability through the mitochondria-mediated intrinsic apoptotic signaling pathway. Rat lung microvascular endothelial cells grown on Transwell inserts, chamber slides, or dishes were treated with recombinant TNF-α (10 ng/ml) in the presence or absence of a caspase-3 inhibitor, Z-DEVD-FMK (100 μM). Fluorescein isothiocyanate (FITC)-albumin (5 mg/ml) was used as a marker of monolayer permeability. Mitochondrial reactive oxygen species (ROS) was determined using dihydrorhodamine 123 and mitochondrial transmembrane potential using JC-1. The adherens junction integrity and actin cytoskeletal organization were studied using β-catenin immunofluorescence and rhodamine phalloidin, respectively. Caspase-3 activity was measured fluorometrically. The pretreatment with Z-DEVD-FMK (100 μM) attenuated TNF-α-induced (10 ng/ml) disruption of the adherens junctions, actin stress fiber formation, increased caspase-3 activity, and monolayer hyperpermeability (p < 0.05). TNF-α (10 ng/ml) treatment resulted in increased mitochondrial ROS formation and decreased mitochondrial transmembrane potential. Intrinsic apoptotic signaling-mediated caspase-3 activation plays an important role in regulating TNF-α-induced endothelial cell hyperpermeability.