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The Journal of Immunology, 2003, 171: 1526-1533.
Copyright © 2003 by The American Association of Immunologists

TRAIL Induces Apoptosis and Inflammatory Gene Expression in Human Endothelial Cells 1

Jie Hui Li*,{dagger}, Nancy C. Kirkiles-Smith*,{dagger}, Jennifer M. McNiff{dagger},{ddagger} and Jordan S. Pober2,*,{dagger},{ddagger}

* Interdepartmental Program in Vascular Biology and Transplantation, Boyer Center for Molecular Medicine, and Departments of {dagger} Pathology and {ddagger} Dermotology, Yale University School of Medicine, New Haven, CT 06510


    Abstract
 Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 
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. Incubation with TRAIL for 15 h causes ~30% of cultured EC to die, as assessed by propidium iodide uptake. Death is apoptotic, as assessed by Annexin V staining, 4',6'-diamidino-2-phenylindole staining, and DNA fragment ELISA. EC death is increased by cotreatment with cycloheximide but significantly reduced by caspase inhibitors or transduced dominant-negative Fas-associated death domain protein. In surviving cells, TRAIL activates NF-{kappa}B, induces expression of E-selectin, ICAM-1, and IL-8, and promotes adhesion of leukocytes. Injection of TRAIL into human skin xenografts promotes focal EC injury accompanied by limited neutrophil infiltration. These data suggest that TRAIL is an inducer of tissue injury in humans, an outcome that may influence antitumor therapy with TRAIL.


    Introduction
 Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 
TRAIL (APO2 ligand) is a member of the TNF family (1, 2), and TRAIL-Rs belong to the TNFR family. The cytoplasmic regions of TRAIL-R1 (DR4) (3) and TRAIL-R2 (DR5) (4, 5) contain a conserved death domain, a protein-protein interaction region, initially identified in CD95 (also known as APO-1/Fas) and TNFR1 (CD120a), as well as in the cytoplasmic adapter molecules Fas-associated death domain (FADD)3 (also known as mediator of receptor-induced toxicity-1 or MORT-1) and TNFR-associated death domain proteins, which interact with these receptors. Upon TRAIL binding, TRAIL-R1 or -R2 recruit FADD, and FADD, in turn, recruits procaspase-8 (6, 7) to form a death-inducing signaling complex. Within the death-inducing signaling complex, procaspase-8 undergoes autocatalytic activation, initiating a caspase cascade that leads to apoptotic cell death. Three other TRAIL-Rs, TRAIL-R3 (TRAIL receptor without an intracellular domain or TRID/DcR1/lymphocyte inhibitor of TRAIL or LIT) (8), TRAIL-R4 (7, 9), and osteoprotegerin (10), which do not have death domains, may function as decoy receptors to protect cells from TRAIL-induced apoptosis (5, 8). In some cell types, TRAIL binding to TRAIL-R1, -R2, and/or -R4 may also activate NF-{kappa}B (11, 12), leading to transcription of genes known to antagonize the FADD/caspase-8 death pathway and/or to promote inflammation. NF-{kappa}B activation may be initiated by recruitment of an alternative death domain-containing adapter molecule, known as receptor-interacting protein (13). TRAIL ligation on human glioma tumor cells also leads to activation of transcription factor AP-1 (14). Cumulatively, these observations suggest that TRAIL, like TNF, may in parallel activate transcription/translation-independent pathways of apoptosis as well as antiapoptotic/proinflammatory pathways that depend upon NF-{kappa}B- and/or AP-1-mediated new gene expression. The outcome of TRAIL binding to any given cell type may depend upon the relative strengths or kinetics of activation of these competing responses (15, 16).

In a variety of rodent tumor models, including those involving human xenografted tumor cells, human TRAIL can selectively kill the tumor cells without appreciable host toxicity (17, 18, 19). This wide therapeutic window has raised hopes that TRAIL can be useful in the treatment of human cancers. Human TNF initially showed a favorable therapeutic window in mouse tumor models but has generally proven to be too toxic for human therapy (20). The increased toxicity of TNF observed in the clinic may be related to the fact that human TNF can act on human cells through two receptors, TNFR1 (CD120a) and TNFR2 (CD120b) (21), but can act on mouse cells only through TNFR1 (22, 23). Mouse TNF, which can engage both TNFR types in rodents, is much more toxic for mice than is human TNF (23). Mouse TRAIL-Rs are incompletely characterized, and the capacity of human TRAIL to interact with different mouse receptors is unknown. Much of the antitumor efficacy of TNF is mediated through effects on vascular endothelial cells (EC) (24, 25). In cultured human EC, human TNF causes apoptosis, especially in the presence of RNA or protein synthesis inhibitors such as actinomycin D or cycloheximide (CHX), respectively. TNF also activates both NF-{kappa}B and AP-1 in EC, leading to the expression of proinflammatory proteins, such as E-selectin (CD62E), ICAM-1 (CD54), and IL-8. The balance of TNF responses generally favors activation rather than apoptosis. We wondered whether TRAIL would also act on human EC, and if so, what the responses to TRAIL signaling might be.

In this study, we report the effects of recombinant human TRAIL on cultured human EC, including both human umbilical vein EC (HUVEC) and human dermal microvascular EC (HDMEC), as well as upon resting human EC in human skin xenografts transplanted on SCID/beige mice. We find that cultured human EC express death domain-containing TRAIL-Rs, and that recombinant human TRAIL protein triggers FADD-caspase-8-dependent apoptosis in EC. TRAIL also activates NF-{kappa}B, resulting in E-selectin, ICAM-1, and IL-8 expression and increased leukocyte binding. TRAIL is more potent than TNF as an inducer of apoptosis, but less potent than TNF as an activator of EC inflammatory gene expression. Importantly, TRAIL injected into human skin xenografts results in focal endothelial damage with little accompanying neutrophil recruitment. These data suggest that TRAIL may be an inducer of normal tissue injury in humans.


    Materials and Methods
 Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 
Reagents and cells

Recombinant human TRAIL, TNF-{alpha}, recombinant human Fas-Fc, recombinant human TRAIL-R2-Fc, caspase-8 selective inhibitor Z-Ile-Glu-Thr-Asp-fluoromethyl ketone, and caspase-3 selective inhibitor Z-Asp-Glu-Val-Asp fluoromethyl ketone were from R&D Systems (Minneapolis, MN). CHX, 4',6'-diamidino-2-phenylindole (DAPI), and pyrrolidine dithiolcarbamate (PDTC) were from Sigma-Aldrich (St. Louis, MO). A cell death detection DNA fragment ELISA kit and an annexin V-FITC staining kit were purchased from Roche (Indianapolis, IN) and BD PharMingen (San Diego, CA), respectively.

The following Abs were used: rabbit anti-I{kappa}B{alpha} and anti-TRAIL-R1 (Santa Cruz Biotechnology, Santa Cruz, CA); mouse anti-TRAIL-R2 mAb (eBioscience, San Diego, CA); rabbit anti-TRAIL-R4 and anti-FADD (Chemicon, Temecula, CA); mouse anti-human {beta}-actin (Novus Biologicals, Littleton, CO), mouse anti-human E-selectin (ascites preparations of H4/18) (26); mouse anti-human ICAM-1 (Immunotech, Marseille, France); isotype control Ab K16/16 (26); goat anti-rabbit IgG HRP-conjugated or anti-mouse IgG FITC-conjugated (Jackson ImmunoResearch, West Grove, PA).

HUVEC and HDMEC were isolated and cultured as described (26) and were used at passage levels 2 to 4. Such cultures are uniformly positive for von Willlebrand factor and CD31 and lack detectable contamination by CD45-expressing leukocytes. HEK293, HeLa, and HL-60 cells were obtained from the American Type Culture Collection (Manassas, VA) and cultured in DMEM medium containing 10% FBS (Life Technologies, Grand Island, NY).

Construction and transduction with recombinant retroviral vector

Plasmid pcDNA3 AU1-FADDmt (human FADD dominant negative (FADD.DN) with AU1 epitope tag) (27), provided by Dr. V. Dixit (Genentech, South San Francisco, CA), was subcloned into the pFB retroviral vector (Stratagene, La Jolla, CA) using PCR with primers 5'-CGACTCACTATAGGGAGACCCA-3' and 5'-GCGGCCGCTCAGGACGCTTCGGAGGTA-3', and topoisomerase cloning techniques (Invitrogen, Carlsbad, CA). The pFB vector was transfected into packaging cell line PA317 provided by Dr. G. Nolan (Stanford University, Palo Alto, CA) and G418 (Life Technologies)-resistant cells were derived as a source of retrovirus stock. Transduction and G418 selection of HUVEC was accomplished as described (28). In brief, this involved three serial transduction of primary cultures with retrovirus-containing supernatants followed by selection with G418. Approximately 50% of transduced HUVEC survived selection with 0.5 mg/ml G418. Multiple FADD.DN-transduced HUVEC clones were pooled to avoid clonal variability.

Similarly, human TRAIL cDNA was amplified using PCR with human T blast cDNA and two primers, 5'-GGATCATGGCTATGATGGAG-3' and 5'-GCGGCCGCAGTTAGCCAACTAAAAAGGC-3'. The amplified TRAIL cDNA fragment was confirmed by DNA sequencing and was subcloned into the pFB retroviral vector. The pFB vector was transfected into packaging cell PA317. G418 selection, retrovirus stock preparation, and HEK293 transduction were performed as described as for HUVEC. TRAIL expression by the transduced HEK293 was determined by TRAIL-R2-Fc staining and FACS analysis.

Assessment of TRAIL-mediated apoptosis

We treated 30,000 HUVEC or HDMEC plated in C6 plates with medium alone or with TRAIL for 3–15 h; CHX or caspase inhibitors were included during the entire treatment period. The doses of TRAIL were varied somewhat among experiments, because different HUVEC and HDMEC stocks showed some variability in sensitivity. To assess cell viability, EC were harvested, stained with 25 µg/ml propidium iodide (PI; Molecular Probes, Eugene, OR) for 5 min at 37°C and then subjected to analytic flow cytometry using a FACSort (BD Biosciences, Mountain View, CA). Apoptois of TRAIL-treated EC was assessed by an annexin V-FITC staining kit (BD PharMingen) following the manufacturer’s protocol. Nuclear morphology during EC apoptosis was assessed by DAPI staining and fluorescence microscopy, as described previously (28). DNA fragmentation was measured using a cell death detection ELISA kit (Roche) according to the manufacturer’s instructions.

Quantitation of protein expression

We measured protein expression by immunoblotting or flow cytometric analysis as described previously (28). Immunoblots were analyzed by chemiluminescence and {beta}-actin was used as protein loading control. For flow cytometry, Ab-stained cells were analyzed using FACSort cytometer and CellQuest software. We calculated corrected mean fluorescence intensities by subtracting the mean values of cells stained with the irrelevant control mAb from that of cells stained with specific primary mAb.

RT-PCR analysis

We performed total RNA extraction, reverse transcription, and PCR amplification as described previously (28, 29). The primers used for TRAIL-Rs were as follows: TRAIL-R1, 5'-ATGGCGCCACCACCAGCTAGA-3' and 5'-TGAGCAACGCAGACTCGCTGT-3'; TRAIL-R2, 5'-CAGGTGTGATTCAGGTGAAGT-3' and 5'-GGACATGGCAGAGTCTGCAT-3'; TRAIL-R4 5'-CTCCCTTCTCATGGGACTTTGG-3' and 5'-CCACCAGTTGGTCCTGAATTG-3'. We separated and visualized the RT-PCR products by electrophoresis in 1.2% agarose gel using ethidium bromide and UV illumination; identification of amplified bands was verified by DNA sequencing.

We performed real-time RT-PCR using a Multicolor Real-Time PCR detection system (Bio-Rad, Hercules, CA) using the SYBR Green PCR core reagents (4304886), according to the recommended protocol, to determine the threshold cycle (Tc). The primer sequences used were as follows: E-selectin, 5'-GAATGTGTAGAGACCATCATAATAAT-3' and 5'-AGGAAGAATTGRAGCTGAAGTTT-3'; ICAM-1, 5'-CTGTTCCCAGGACCTGGCAAT-3' and 5'-AGGCAGGAGCAACTCCTTTTTA-3'; IL-8, 5'-CTCTTGGCAGCCTTCCTGATT-3' and 5'-ACTCTCAATCACTCTCAGTTCT-3; and {beta}-actin, 5'-TGCACCACACCTTCTACAATGA-3' and 5'-CAGCCTGGATAGCAACGTACAT-3'. In TRAIL-treated HUVEC or HDMEC, up-regulation of E-selectin, ICAM-1, and IL-8 were expressed as fold induction (FI), calculated as follows: FI = 2- 7-[TRAIL (Tc target - Tc {beta}-actin) - control (Tc target - Tc {beta}-actin)].

NF-{kappa}B promoter reporter assay

We transiently transfected HUVEC cells with NF-{kappa}B promoter-firefly luciferase and {beta}-actin promoter-Renilla luciferase reporter plasmids using a DEAE-dextran protocol (30). The transfected HUVEC were incubated with 50 ng/ml TRAIL or TNF for 7 h, and their luciferase activity was determined using a Promega (Madison, WI) Dual-Luciferase reporter assay system according to the manufacturer’s instruction, and the activity of the NF-{kappa}B promoter-reporter was normalized to that of the {beta}-actin promoter-reporter.

HL-60 cell adherence assay

We seeded HUVEC and HDMEC in 24-well plates, incubated cells with TRAIL or TNF for 5 h, and then added HL-60 cells loaded with calcein-AM (Molecular Probes) at a ratio of 5:1 of leukocytes to EC. After 30 min, unbound HL-60 cells were removed by washing gently three times with 1 ml of PBS, and the retained calcein per well was determined by fluorometry (Cytofluor2; PerSpective Biosystems, Framingham, MA). Binding was expressed by fluorescence and calculated as follows: (fluorescence associated with treated EC) - (fluorescence associated with untreated EC).

Human skin mouse model

We engrafted human skin on C.B-17 SCID/beige mice (Taconic Farms, Germantown, NY) as described (31), and the grafts were healed in 4–6 wk before use. We then intradermally injected 20 µl of saline vehicle, TRAIL (0.6 µg), or TNF (0.1 µg), and harvested the grafts 6 h later. The doses used were determined as optimal from preliminary experiments. Grafts were paraffin embedded, sectioned, and stained with H&E (31). The degreeof graft microvascular injury was evaluated from the H&E-stained section by a dermatopathologist (J. McNiff) blinded to the treatment protocols, assessing EC morphology, thrombosis, and leukocyte infiltration.


    Results
 Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 
TRAIL-R expression by human EC and cell lines

The goal of this study was to determine the effects of TRAIL on normal human EC in vitro and in vivo. We first examined whether cultured HUVEC and HDMEC express signaling TRAIL-Rs (i.e., TRAIL-R1, -R2, and -R4). Using a sensitive but nonquantitative RT-PCR method, we could readily detect TRAIL-R1 and -R2 mRNA in both cell types, as well as control cell lines HeLa or HEK 293 (Fig. 1a). TRAIL-R4 mRNA was detectable in HUVEC, HeLa, and HEK293, but not in HDMEC (Fig. 1a). We also measured TRAIL-R2 cell surface protein expression by indirect immunofluorescence and flow cytometry. As shown in Fig. 1b, HDMEC, HUVEC, HeLa, and HEK293 all express TRAIL-R2. Expression in HUVEC is somewhat greater than in HDMEC. Available Abs that react with TRAIL-R1 and -R4 do not work in flow cytometry, so we examined protein levels of these receptors by immunoblotting. TRAIL-R1 and -R4 proteins were detected in HUVEC, HeLa, and HEK293 (Fig. 1c), but HDMEC expressed only TRAIL-R1, consistent with the RT-PCR data (a).



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FIGURE 1. TRAIL-R expression by human EC and control cells. a, RT-PCR assessment of TRAIL-R1, -R2, and -R4 mRNA expression by HeLa, HEK293, HUVEC, and HDMEC. b, FACS analysis of cell surface TRAIL R2 expression using anti-human TRAIL R2 immunostaining. The filled curve is human TRAIL-R2 stained; the open curve is the nonbinding isotype Ab control. c, Immunoblot analysis of TRAIL-R1 and -R4 using rabbit anti-human TRAIL-R1 Ab or rabbit anti-human TRAIL-R4 Ab; immunoblotting of {beta}-actin was used as a loading control. All experiments were repeated at least three times with similar results.

 
TRAIL-triggered apoptosis of human EC

Next, we examined whether rTRAIL caused death of cultured HUVEC or HDMEC using PI exclusion and flow cytometry (28). As shown in Fig. 2a, ~30% of HUVEC lose membrane integrity after treatment with 20 ng/ml TRAIL for 15 h, compared with 7.8% of cells in replicate control cultures not treated with TRAIL. Fifteen hours was determined in preliminary experiments to display maximal cell death, and longer incubations lead to interference with the assay by cell-derived debris. The dose-response curve varied somewhat in different HUVEC isolates, and cells showed progressive loss of sensitivity to TRAIL with serial passage (data not shown). HDMEC showed similar susceptibility to TRAIL (Fig. 2c). Cell death of both cell types was increased in the presence of the protein synthesis inhibitor CHX (Fig. 2, b and c). PI exclusion is highly quantitative but does not distinguish late apoptotic from necrotic cell death. To determine whether TRAIL-triggered HUVEC death was apoptotic or necrotic, we incubated HUVEC with 50 ng/ml TRAIL for 2.5, 5, or 10 h, and stained cells with Annexin V-FITC. At 5 or 10 h, ~15% of HUVEC showed evidence of an early apoptotic phase which is Annexin V positive (Fig. 3a). In addition, TRAIL-induced HUVEC death is characterized by nuclear condensation and fragmentation, a more specific test of apoptosis (Fig. 3b), as shown by DAPI staining and fluorescence microscopy. The results of a DNA fragment ELISA also supported the conclusion that death caused by TRAIL with or without CHX, is apoptosis (Fig. 3c). Although HDMEC do not express TRAIL-R4, both HUVEC and HDMEC showed similar sensitivity to TRAIL (Fig. 2, b and c), which suggests that TRAIL-R4 expressed on HUVEC, but not HDMEC, is not a major inhibitor of TRAIL-mediated EC apoptosis. TNF does not induce a significant degree of apoptosis in either HUVEC or HDMEC unless CHX is added (data not shown).



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FIGURE 2. Recombinant TRAIL-triggered human EC death. TRAIL, CHX, or caspase inhibitors were included during the entire treatment period. a, Dose response of HUVEC susceptibility to TRAIL addition. HUVEC were treated with TRAIL at the concentrations indicated for 15 h, and the cell viability was determined by PI exclusion staining as described as in Materials and Methods. b, Effects of protein synthesis and caspase inhibitors on TRAIL-induced death. TRAIL-induced HUVEC death was determined by PI exclusion in the presence or absence of CHX (3 µg/ml) and caspase inhibitors Z-DEVD-FMK (40 µM) and Z-IETD-FMK (40 µM). c, Effects of TRAIL on HDMEC TRAIL-induced HDMEC death was assessed by PI exclusion in the presence or absence of CHX (3 µg/ml). d, FADD.DN expression by retroviral FADD.DN-transduced HUVEC (HUVEC.DN) or by HUVEC.mock was determined by immunoblotting using rabbit anti-human FADD Ab. The sensitivity of these two cell cultures to TRAIL-triggered death signal(s) was determined by PI exclusion staining after incubation with TRAIL for 8 h in the presence of CHX (3 µg/ml). e, The sensitivity of HUVEC to membrane-bound TRAIL was determined by PI exclusion staining after coculture with HEK293.TRAIL effector, or control HEK293.pFB, at a ratio of 1:1 for 15 h. Killing specificity was determined in the presence or absence of TRAIL-R2-Fc or human Fas-Fc. Both TRAIL-R2-Fc and human Fas-Fc were added at a concentration of 1 µg/ml and were incubated with HUVEC from the beginning to the end of the assay. Because HUVEC were mixed with effectors at 1:1, the true number (percentage) of dead HUVEC may be twice that indicated in the Fig. 2e. All experiments were repeated at least three times with similar results.

 


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FIGURE 3. TRAIL-mediated killing of HUVEC is apoptotic. a, Annexin V-FITC staining. At the indicated time points, HUVEC cells treated by 50 ng/ml TRAIL were stained with annexin V-FITC, as analyzed by FACS. The data show a time-dependent increase in annexin V-positive cells. b, Examination of nuclear changes. HUVEC were incubated with or without 50 ng/ml TRAIL for 10 h, and nuclear morphology was examined by DAPI staining as described in Materials and Methods. Note the nuclear condensation and fragmentation in the TRAIL-treated group, which is indicative of apoptosis. c, Assessment of apoptosis by DNA fragment ELISA. HUVEC cells were incubated with 50 ng/ml TRAIL for 15 h in the presence or absence of CHX (3 µg/ml). HUVEC were harvested and fragmented DNA was quantified with a DNA fragment ELISA kit. Absorbance at 450 nm indicates the amounts of fragmented DNA released from apoptotic HUVEC. All experiments were repeated at least three times with similar results.

 
To determine whether FADD is the adapter protein in human EC for the TRAIL-R-mediated death signaling, we prepared FADD.DN-transduced HUVEC (Fig. 2d). Most FADD.DN-expressing HUVEC survived treatment with 15 or 100 ng/ml TRAIL plus CHX for 8 h, in contrast to mock-transduced HUVEC (Fig. 2d). Protection with FADD.DN is not complete, and the difference between specific and mock-transduced cells somewhat narrowed at later times (data not shown). Consistent with these data, HUVEC death was reduced by selective inhibitors of caspase-8 and -3 (Fig. 2, b and c). We concluded from these studies that TRAIL initiates apoptosis of normal human EC via a FADD-caspase-8 pathway.

TRAIL is normally a membrane-bound ligand expressed by monocytes, T lymphocytes, dendritic cells, and NK cells (15). To address whether EC could be killed by membrane-bound TRAIL, HUVEC were cocultured with HEK293-TRAIL, or with control HEK293-pFB at 1:1 ratios for 15 h. The viability of the mixed population was then determined by PI exclusion. Coculture of HUVEC with HEK293-TRAIL resulted in a reproducible increase of PI-stained cells (~15%), compared with HUVEC culture alone or with mock HEK293-pFB (~5%) (Fig. 2e). Moreover, the HEK293-TRAIL-mediated cytotoxicity was markedly inhibited by 1 µg/ml TRAIL-R2-FC, but not by human Fas-Fc (Fig. 2e). Because only 50% of the cultures are HUVEC, this increase in HUVEC death is probably double that measured for the whole populations, similar to the sensitivity of HUVEC to the soluble rTRAIL used in our experiments.

TRAIL-triggered inflammatory gene expression in EC

Because in the absence of CHX, 70% of EC are not killed by TRAIL, we also examined the activation response of these cells. After treatment with TRAIL for 6–7 h, we observed an increase of E-selectin expression on HUVEC and HDMEC demonstrated by FACS (the time point was selected because of preliminary experiments for the optimal level of E-selectin protein expression) (Fig. 4a). This TRAIL response is consistently smaller than that induced by TNF (Fig. 4a). TRAIL was also effective at inducing E-selectin expression in HDMEC (Fig. 4b). Although our preparations of TRAIL contained only very low levels of endotoxin contaminant (tested by the manufacturer), we excluded the possibility that LPS contamination in the rTRAIL reagent was responsible for the E-selectin induction in EC by heating TRAIL at 80°C for 10 min before addition to EC. This treatment, which does not inactivate LPS actions on EC(data not shown), abolished induction of E-selectin expression in EC by TRAIL (Fig. 4a). The response to TRAIL was not confined to induction of E-selectin. ICAM-1 was also up-regulated in HUVEC surviving TRAIL treatment (Fig. 4c). We also examined the mRNA levels of E-selectin, ICAM-1, and IL-8 in TRAIL-stimulated human EC using real-time quantitative RT-PCR. Incubation with 50 ng/ml TRAIL for 3 h increased expression of E-selectin, ICAM-1, and IL-8 mRNAs in both HUVEC and HDMEC (Fig. 4d).



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FIGURE 4. Inflammatory gene expression and function by TRAIL-stimulated EC. a and b, Human EC were stimulated with TRAIL, heated TRAIL, and TNF for 6 h, and their E-selectin expression levels were evaluated by flow cytometry. The filled curve is stained with anti-human {beta}-selectin Ab; the open curve is the nonbinding isotype Ab control in HUVEC (a), a HDMEC (b). ICAM-1 (c) expression on HUVEC after stimulation for 6 h with 50 ng/ml TRAIL. d, HUVEC and HDMEC were incubated with or without 50 ng/ml TRAIL for 3 h. mRNA for E-selectin, ICAM-1, and IL-8 were assessed using an iCycler iQTM multicolor real-time PCR detection system, as described in Materials and Methods. Fold induction of E-selectin, ICAM-1, and IL-8, normalized relative to expression in the absence of TRAIL. e, HL-60 cell adherence of TRAIL-activated EC. TRAIL- or TNF-activated HUVEC and HDMEC were incubated with calcein-AM-labeled HL-60 cells for 30 min, and after washing, retained calcein was measured using the fluorescence multiwell plate reader Cytofluor2, and the induced specific HL-60 binding was calculated. All experiments were repeated at least three times with similar results.

 
The functional consequence of adhesion molecule and chemokine expression by EC is the binding and activation of leukocytes. To determine whether the degree of activation observed in TRAIL-treated EC could be biologically significant, we tested the adhesion of HL-60 leukocytes to HUVEC, and to HDMEC, pretreated with vehicle only, with TRAIL, or with TNF. As shown in Fig. 4e, 50 ng/ml TRAIL pretreatment significantly increased the binding of leukocytes to EC over control-treated cells, but once again, the effect of TRAIL was less than that produced by 50 ng/ml TNF (Fig. 4e).

TNF-mediated induction of proinflammatory genes in EC is dependent upon the activation of NF-{kappa}B via degradation of I{kappa}B{alpha}. As demonstrated by immunoblot, TRAIL causes I{kappa}B{alpha} degradation in HUVEC, HDMEC, and HEK 293 cells (Fig. 5a). TRAIL-induced NF-{kappa}B activation in HUVEC was more directly examined using an NF-{kappa}B promoter reporter gene assay. Stimulation with 50 ng/ml TRAIL for 7 h caused an increase of luciferase activity driven by NF-{kappa}B, although this response was smaller than that caused by 50 ng/ml TNF (Fig. 5b). We also find that the NF-{kappa}B inhibitor PDTC prevented TRAIL-induced E-selectin expression in HUVEC (Fig. 5c), confirming a link between NF-{kappa}B activation and the proinflammatory response of TRAIL in these cells.



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FIGURE 5. TRAIL-induced NF-{kappa}B activation. a, HUVEC, HDMEC, and HEK293 cells were treated with TRAIL, as indicated, and cell lysates were size fractionated by SDS-PAGE and analyzed for I{kappa}B{alpha} by immunoblotting. {beta}-actin was used as a loading control. Upper bands, I{kappa}B{alpha}; lower bands, {beta}-actin. b, TRAIL-induced NF-{kappa}B reporter activity was measured in HUVEC transiently transfected with pBIIXLuc and p{beta}-actin-Rluc. The firefly and Renilla luciferase activities were measured, and relative luciferase activity was calculated as described. c, HUVEC were treated with 50 ng/ml TRAIL for 6 h, in the presence or absence of PDTC, and the cell surface E-selectin expression levels were evaluated by flow cytometry. The filled curve is stained with E-selectin Ab, and the open curve is the nonbinding isotype Ab control. All experiments were repeated three times with similar results.

 
TRAIL-induced EC injury and inflammation

To examine the effects of TRAIL on human EC in vivo, we intradermally injected TRAIL into stable human skin xenografts on SCID/beige mice. Histological analysis confirmed that both TNF and TRAIL resulted in epidermal and vessel injury (Fig. 6, b–d). Vascular damage was seen as either loss of EC or formation of microthrombi (Fig. 6, b–d). This was accompanied by local infiltration of neutrophils and mononuclear cells (Fig. 6, b–d). The extent of leukocyte recruitment was much greater in TNF-injected skin than in TRAIL-injected skin. Heat-treated TRAIL did not induce inflammation or endothelial injury, excluding the possibility of an LPS contaminant producing these responses (data not shown).



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FIGURE 6. TRAIL-induced tissue injury and inflammation in human skin. H&E-stained sections of human skin xenografts from C.B-17 SCID/beige mice 6 h after intradermal injection with vehicle saline alone (a), TNF (0.1 µg) (b), or TRAIL (0.6 µg) (c and d). a, After saline treatment, normal tissue shows healthy vessels, intact EC, and no fibrin deposition. b, After 0.1 µg TNF treatment, the epidermis shows striking keratinocyte cell necrosis, and damaged EC; c and d, after 0.6 µg TRAIL treatment; arrows show damaged vessels. Only minimal inflammation is seen, judged by scant neutrophil infiltration, loss of some EC, and partial thrombosis (c). Necrotic keratinocytes are observed in epidermis, and superficial dermal vessels show patchy loss of EC with fibrin deposition. All experiments were repeated three times with similar results.

 

    Discussion
 Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 
TRAIL-Rs are widely expressed on many cell types, but the effects of TRAIL on normal human tissues have not been described previously, and the physiological function(s) of this novel TNF family member remains unknown (15, 32). We studied the expression of TRAIL-Rs and responses to TRAIL in normal human EC in vivo and in vitro. Following incubation with TRAIL for 15 h, ~30% of cultured EC lose membrane integrity (Fig. 2, a–c). EC death is increased by cotreatment with CHX but significantly reduced by selective caspase inhibitors or transduced FADD.DN (Fig. 2, b–d). Moreover, experiments with Annexin V staining, DAPI nuclear staining, and a DNA fragment ELISA demonstrate that TRAIL-triggered HUVEC death is predominantly apoptotic (Fig. 3). Most EC do not die in response to TRAIL in the absence of CHX, prompting us to examine other related responses. We found that TRAIL-treated EC also show NF-{kappa}B-dependent activation responses and inflammatory gene expression that results in adhesion of leukocytes (Figs. 4 and 5). Most importantly, TRAIL induces EC damage and tissue injury in normal human skin in vivo. These responses are qualitatively similar to those induced by TNF (Fig. 6). However, compared with TNF, TRAIL is a stronger inducer of apoptosis in vitro (Fig. 2, a–c, e) but a weaker activator of NF-{kappa}B (b). In vivo, the TRAIL response also caused less EC activation and inflammation than TNF but resulted in comparable levels of EC injury (Fig. 6). The dose responses of both HUVEC and HDMEC to TRAIL varied somewhat among isolates, similar to the previously noted variability of HUVEC cultures to TNF or IL-1 (33). In addition, apoptotic responses diminished somewhat with passage level. This is also true for the apoptosis response to TNF (J. Li and J. Pober, unpublished observation). The explanation for these changes is unknown.

Previous investigations have reported the toxic effects of TRAIL on normal human cells, including hepatocytes (34), brain cells (35), and erythropoietic cells (36). In this regard, the effects on EC are not unique. However, the effects of injury to EC may be more biologically significant, because this can be amplified in vivo through secondary thrombosis and consequent tissue ischemia (Fig. 6, c and d). Our observations that HUVEC and HDMEC are susceptible to TRAIL death signals differ from those reported previously by others (17, 18). The basis of this difference is unclear but could result from the methods used to assess cell death, from the state of the EC cultures or from the potency of the TRAIL preparations used. We detected death by loss of membrane integrity, by Annexin V binding, by nuclear condensation, and by DNA fragmentation, which may be more sensitive than crystal violet staining used by other investigators (17, 18). We also do not know the characterization of EC cultures used in the previous published study. It may be relevant that HUVEC become increasingly resistant to apoptotic signals provided by TNF, CD95L, as well as (or) TRAIL after several passages in vitro. The different recombinant versions of TRAIL may also vary widely in biochemical properties and potential for cellular and whole animal toxicity (37). Soluble TRAIL could also be a weaker apoptosis inducer compared with membrane-bound TRAIL, the physiological form of this ligand on activated leukocytes. In one study, apoptosis through TRAIL-R2 was only activated by membrane-bound TRAIL or soluble TRAIL secondarily cross-linked by Abs (38). However, our results with TRAIL-transduced HEK293 cells do not support a major difference in the susceptibility of HUVEC to membrane-bound vs soluble ligand used in this study.

The system of cell receptors for TRAIL is complex. We have examined the expression of cultured HUVEC and HDMEC for those TRAIL-Rs involved in signaling, namely TRAIL-R1, -R2, and -R4. HUVEC express all three receptors, whereas HDMEC express only TRAIL-R1 and -R2. As shown in Fig. 1b, the expression level of TRAIL-R2 in HDMEC is somewhat less than that in HUVEC. We do not know the significance of these differences, because both cell types showed very similar dose-apoptotic responses to TRAIL addition. We do not know whether the death responses we have observed are mediated by TRAIL-R1 or -R2. We observed TRAIL-induced human EC injury in vivo as well as in vitro. We do not know which receptors are expressed by mouse EC or whether human TRAIL can act through all mouse receptors. Such information could shed light on the species difference of tissue injury produced by human TRAIL.

The TRAIL pathway represents a potentially promising target for anticancer therapy (17, 18, 19, 39), and the finding reported in this study that TRAIL induces apoptosis and inflammatory gene expression in EC does not exclude this possibility. TNF exerts its primary antitumor action in vivo via damage of tumor vessels. Our finding suggests TRAIL may also have indirect antitumor effects in addition to direct cytotoxicity toward tumor cells. TNF appears more active on tumor vessels than normal vessels, and it will be interesting to test whether TRAIL also shows such different sensitivity. A proinflammatory effect of a cytokine is also not necessarily a problem for tumor therapy. The inflammatory response provides signals that stimulate APCs, such as dendritic cells to express molecules that promote binding, stimulation, and activation of lymphocytes (40). In other words, the EC injury response we have observed in human skin after TRAIL treatment (Fig. 6c) could facilitate host immune responses by acting as an adjuvant.

In summary, we have found that recombinant human TRAIL can both injure and activate human EC in vitro and in vivo. Compared with TNF, TRAIL is potent at causing injury but less effective at stimulating inflammation. These findings need to be considered in planning and interpreting human therapeutic trials with rTRAIL as a treatment for cancer and for evaluating the physiological role of endogenous TRAIL in immune and inflammatory reactions.


    Acknowledgments
 
We thank our colleagues Jae Choi, David Enis, Martin S. Kluger, and Keyvan Mahboubi for their critical suggestions for this manuscript. We are also grateful to Louise Benson, Gwendolyn Davis, and Lisa Grass for excellent technical assistance with cell culture.


    Footnotes
 
1 This work was supported by National Institutes of Health Grant HL62188 (to J.S.P.). Back

2 Address correspondence and reprint requests to Dr. Jordan S. Pober, Boyer Center for Molecular Medicine, Yale University School of Medicine, 295 Congress Avenue, New Haven, CT 06510. E-mail address: jordan.pober{at}yale.edu Back

3 Abbreviations used in this paper: FADD, Fas-associated death domain protein; FADD.DN, FADD dominant negative; EC, endothelial cell; HUVEC, human umbilical vein EC; HDVEC, human dermal microvascular EC; CHX, cycloheximide; DAPI, 4',6'-diamidino-2-phenylindole; PDTC, pyrrolidine dithiolcarbamate; PI, propidium iodide; Tc, threshold cycle. Back

Received for publication December 31, 2002. Accepted for publication May 22, 2003.


    References
 Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Pitti, R. M., S. A. Marsters, S. Ruppert, C. J. Donahue, A. Moore, A. Ashkenazi. 1996. Induction of apoptosis by Apo-2 ligand, a new member of the tumor necrosis factor cytokine family. J. Biol. Chem. 271:12687.[Abstract/Free Full Text]
  2. Wiley, S. R., K. Schooley, P. J. Smolak, W. S. Din, C. P. Huang, J. K. Nicholl, G. R. Sutherland, T. D. Smith, C. Rauch, C. A. Smith, et al 1995. Identification and characterization of a new member of the TNF family that induces apoptosis. Immunity 3:673.[Medline]
  3. Pan, G., K. O’Rourke, A. M. Chinnaiyan, R. Gentz, R. Ebner, J. Ni, V. M. Dixit. 1997. The receptor for the cytotoxic ligand TRAIL. Science 276:111.[Abstract/Free Full Text]
  4. Walczak, H., M. A. Degli-Esposti, R. S. Johnson, P. J. Smolak, J. Y. Waugh, N. Boiani, M. S. Timour, M. J. Gerhart, K. A. Schooley, C. A. Smith, et al 1997. TRAIL-R2: a novel apoptosis-mediating receptor for TRAIL. EMBO J. 16:5386.[Medline]
  5. Sheridan, J. P., S. A. Marsters, R. M. Pitti, A. Gurney, M. Skubatch, D. Baldwin, L. Ramakrishnan, C. L. Gray, K. Baker, W. I. Wood, et al 1997. Control of TRAIL-induced apoptosis by a family of signaling and decoy receptors. Science 277:818.[Abstract/Free Full Text]
  6. Sprick, M. R., M. A. Weigand, E. Rieser, C. T. Rauch, P. Juo, J. Blenis, P. H. Krammer, H. Walczak. 2000. FADD/MORT1 and caspase-8 are recruited to TRAIL receptors 1 and 2 and are essential for apoptosis mediated by TRAIL receptor 2. Immunity 12:599.[Medline]
  7. Kischkel, F. C., D. A. Lawrence, A. Chuntharapai, P. Schow, K. J. Kim, A. Ashkenazi. 2000. Apo2L/TRAIL-dependent recruitment of endogenous FADD and caspase-8 to death receptors 4 and 5. Immunity 12:611.[Medline]
  8. Degli-Esposti, M. A., P. J. Smolak, H. Walczak, J. Waugh, C. P. Huang, R. F. DuBose, R. G. Goodwin, C. A. Smith. 1997. Cloning and characterization of TRAIL-R3, a novel member of the emerging TRAIL receptor family. J. Exp. Med. 186:1165.[Abstract/Free Full Text]
  9. Degli-Esposti, M. A., W. C. Dougall, P. J. Smolak, J. Y. Waugh, C. A. Smith, R. G. Goodwin. 1997. The novel receptor TRAIL-R4 induces NF-{kappa}B and protects against TRAIL-mediated apoptosis, yet retains an incomplete death domain. Immunity 7:813.[Medline]
  10. Emery, J. G., P. McDonnell, M. B. Burke, K. C. Deen, S. Lyn, C. Silverman, E. Dul, E. R. Appelbaum, C. Eichman, R. DiPrinzio, et al 1998. Osteoprotegerin is a receptor for the cytotoxic ligand TRAIL. J. Biol. Chem. 273:14363.[Abstract/Free Full Text]
  11. Schneider, P., M. Thome, K. Burns, J. L. Bodmer, K. Hofmann, T. Kataoka, N. Holler, J. Tschopp. 1997. TRAIL receptors 1 (DR4) and 2 (DR5) signal FADD-dependent apoptosis and activate NF-{kappa}B. Immunity 7:831.[Medline]
  12. Chaudhary, P. M., M. Eby, A. Jasmin, A. Bookwalter, J. Murray, L. Hood. 1997. Death receptor 5, a new member of the TNFR family, and DR4 induce FADD-dependent apoptosis and activate the NF-{kappa}B pathway. Immunity 7:821.[Medline]
  13. Lin, Y., A. Devin, A. Cook, M. M. Keane, M. Kelliher, S. Lipkowitz, Z. G. Liu. 2000. The death domain kinase RIP is essential for TRAIL (Apo2L)-induced activation of I{kappa}B kinase and c-Jun N-terminal kinase. Mol. Cell. Biol. 20:6638.[Abstract/Free Full Text]
  14. Choi, C., O. Kutsch, J. Park, T. Zhou, D. W. Seol, E. N. Benveniste. 2002. Tumor necrosis factor-related apoptosis-inducing ligand induces caspase-dependent interleukin-8 expression and apoptosis in human astroglioma cells. Mol. Cell. Biol. 22:724.[Abstract/Free Full Text]
  15. Walczak, H., P. H. Krammer. 2000. The CD95 (APO-1/Fas) and the TRAIL (APO-2L) apoptosis systems. Exp. Cell Res. 256:58.[Medline]
  16. Strasser, A., L. O’Connor, V. M. Dixit. 2000. Apoptosis signaling. Annu. Rev. Biochem. 69:217.[Medline]
  17. Walczak, H., R. E. Miller, K. Ariail, B. Gliniak, T. S. Griffith, M. Kubin, W. Chin, J. Jones, A. Woodward, T. Le, et al 1999. Tumoricidal activity of tumor necrosis factor-related apoptosis-inducing ligand in vivo. Nat. Med. 5:157.[Medline]
  18. Ashkenazi, A., R. C. Pai, S. Fong, S. Leung, D. A. Lawrence, S. A. Marsters, C. Blackie, L. Chang, A. E. McMurtrey, A. Hebert, et al 1999. Safety and antitumor activity of recombinant soluble Apo2 ligand. J. Clin. Invest. 104:155.[Medline]
  19. Ichikawa, K., W. Liu, L. Zhao, Z. Wang, D. Liu, T. Ohtsuka, H. Zhang, J. D. Mountz, W. J. Koopman, R. P. Kimberly, T. Zhou. 2001. Tumoricidal activity of a novel anti-human DR5 monoclonal antibody without hepatocyte cytotoxicity. Nat. Med. 7:954.[Medline]
  20. Abbruzzese, J. L., B. Levin, J. A. Ajani, J. S. Faintuch, S. Saks, Y. Z. Patt, C. Edwards, K. Ende, J. U. Gutterman. 1989. Phase I trial of recombinant human {gamma}-interferon and recombinant human tumor necrosis factor in patients with advanced gastrointestinal cancer. Cancer Res. 49:4057.[Abstract/Free Full Text]
  21. Tartaglia, L. A., D. V. Goeddel. 1992. Two TNF receptors. Immunol. Today 13:151.[Medline]
  22. Kramer, S. M., B. B. Aggarwal, T. E. Eessalu, S. M. McCabe, B. L. Ferraiolo, I. S. Figari, M. A. J. Palladino. 1988. Characterization of the in vitro and in vivo species preference of human and murine tumor necrosis factor-{alpha}. Cancer Res. 48:920.[Abstract/Free Full Text]
  23. Brouckaert, P., C. Libert, B. Everaerdt, W. Fiers. 1992. Selective species specificity of tumor necrosis factor for toxicity in the mouse. Lymphokine Cytokine Res. 11:193.[Medline]
  24. Palladino, M. A. J., J. S. Patton, I. S. Figari, M. R. Shalaby. 1987. Possible relationships between in vivo antitumour activity and toxicity of tumour necrosis factor-{alpha}. Ciba Found. Symp. 131:21.[Medline]
  25. Palladino, M. A. J., M. R. Shalaby, S. M. Kramer, B. L. Ferraiolo, R. A. Baughman, A. B. Deleo, D. Crase, B. Marafino, B. B. Aggarwal, I. S. Figari, et al 1987. Characterization of the antitumor activities of human tumor necrosis factor-{alpha} and the comparison with other cytokines: induction of tumor-specific immunity. J. Immunol. 138:4023.[Abstract]
  26. Kluger, M. S., D. R. Johnson, J. S. Pober. 1997. Mechanism of sustained E-selectin expression in cultured human dermal microvascular endothelial cells. J. Immunol. 158:887.[Abstract]
  27. Chinnaiyan, A. M., K. O’Rourke, M. Tewari, V. M. Dixit. 1995. FADD, a novel death domain-containing protein, interacts with the death domain of Fas and initiates apoptosis. Cell 81:505.[Medline]
  28. Li, J. H., M. S. Kluger, L. A. Madge, L. Zheng, A. L. Bothwell, J. S. Pober. 2002. Interferon-{gamma} augments CD95 (APO-1/Fas) and pro-caspase-8 expression and sensitizes human vascular endothelial cells to CD95-mediated apoptosis. Am. J. Pathol. 161:1485.[Abstract/Free Full Text]
  29. Biedermann, B. C., J. S. Pober. 1999. Human vascular endothelial cells favor clonal expansion of unusual alloreactive CTL. J. Immunol. 162:7022.[Abstract/Free Full Text]
  30. Karmann, K., W. Min, W. C. Fanslow, J. S. Pober. 1996. Activation and homologous desensitization of human endothelial cells by CD40 ligand, tumor necrosis factor, and interleukin 1. J. Exp. Med. 184:173.[Abstract/Free Full Text]
  31. Murray, A. G., P. Petzelbauer, C. C. Hughes, J. Costa, P. Askenase, J. S. Pober. 1994. Human T-cell-mediated destruction of allogeneic dermal microvessels in a severe combined immunodeficient mouse. Proc. Natl. Acad. Sci. USA 91:9146.[Abstract/Free Full Text]
  32. Locksley, R. M., N. Killeen, M. J. Lenardo. 2001. The TNF and TNF receptor superfamilies: integrating mammalian biology. Cell 104:487.[Medline]
  33. Bender, J. R., M. M. Sadeghi, C. Watson, S. Pfau, R. Pardi. 1994. Heterogeneous activation thresholds to cytokines in genetically distinct endothelial cells: evidence for diverse transcriptional responses. Proc. Natl. Acad. Sci. USA 91:3994.[Abstract/Free Full Text]
  34. Jo, M., T. H. Kim, D. W. Seol, J. E. Esplen, K. Dorko, T. R. Billiar, S. C. Strom. 2000. Apoptosis induced in normal human hepatocytes by tumor necrosis factor-related apoptosis-inducing ligand. Nat. Med. 6:564.[Medline]
  35. Nitsch, R., I. Bechmann, R. A. Deisz, D. Haas, T. N. Lehmann, U. Wendling, F. Zipp. 2000. Human brain-cell death induced by tumour-necrosis-factor-related apoptosis-inducing ligand (TRAIL). Lancet 356:827.[Medline]
  36. Zamai, L., P. Secchiero, S. Pierpaoli, A. Bassini, S. Papa, E. S. Alnemri, L. Guidotti, M. Vitale, G. Zauli. 2000. TNF-related apoptosis-inducing ligand (TRAIL) as a negative regulator of normal human erythropoiesis. Blood 95:3716.[Abstract/Free Full Text]
  37. Lawrence, D., Z. Shahrokh, S. Marsters, K. Achilles, D. Shih, B. Mounho, K. Hillan, K. Totpal, L. DeForge, P. Schow, et al 2001. Differential hepatocyte toxicity of recombinant Apo2L/TRAIL versions. Nat. Med. 7:383.[Medline]
  38. Wajant, H., D. Moosmayer, T. Wuest, T. Bartke, E. Gerlach, U. Schonherr, N. Peters, P. Scheurich, K. Pfizenmaier. 2001. Differential activation of TRAIL-R1 and -2 by soluble and membrane TRAIL allows selective surface Ag-directed activation of TRAIL-R2 by a soluble TRAIL derivative. Oncogene 20:4101.[Medline]
  39. Fulda, S., W. Wick, M. Weller, K. M. Debatin. 2002. Smac agonists sensitize for Apo2L/TRAIL- or anticancer drug-induced apoptosis and induce regression of malignant glioma in vivo. Nat. Med. 8:808.[Medline]
  40. Pardoll, D. M.. 2002. Spinning molecular immunology into successful immunotherapy. Nat. Rev. Immunol. 2:227.[Medline]



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