Relationships between tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and hematopoietic activity in healthy adults

To investigate the relationship between hematopoiesis and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), we measured soluble TRAIL concentrations, reticulocytes, hemograms, and anthropometric variables in 156 healthy subjects. Serum TRAIL concentrations were analyzed by an enzyme immunoassay. Serum ferritin, thyroid hormone, total cholesterol, creatinine, and blood glucose levels were determined. There were no significant differences in blood cell counts and biochemical parameters between the subjects with TRAIL less than 63.5 pg/ml and TRAIL at least 63.5 pg/ml, nor between those with TRAIL at most 47.5 pg/ml (20th percentile) and TRAIL 80.9 pg/ml (80th percentile). However, hemoglobin, mean corpuscular hemoglobin (MCH), and MCH concentration (MCHC) averaged 15.6±0.8 g/dl, 31.9±1.1 pg, and 34.5±0.9 g/dl in the subjects with TRAIL at most 47.5 pg/ml, which were significantly above the values in those with TRAIL at least 80.9 pg/ml (14.7±0.9 g/dl, 30.4±1.3 pg, and 33.2±1.2 g/dl, P<0.05, respectively). Serum TRAIL levels were significantly higher in the subjects with decreased MCH than in those with elevated MCH. Soluble TRAIL concentrations were significantly correlated with hemoglobin (r=–0.25, P<0.05), MCH (r=–0.32, P<0.05), and MCHC (r=–0.29, P<0.05), but not correlated with leukocyte differentials and platelet counts. In conclusion, soluble TRAIL does not seem to influence leukocyte and platelet production but has an important relationship to erythropoiesis in healthy adults.     

肿瘤坏死因子相关凋亡诱导配体与肝细胞凋亡的相关性

肿瘤坏死因子相关的调亡诱导配体是TNF家族成员之一,通过其死亡受体诱导凋亡.研究显示TRAIL/死亡受体途径参与多种肝脏病理过程,本文就TRAIL/死亡受体途径的特性、致凋亡的机制及与肝细胞凋亡关系的最新进展作一综述.     

The involvement of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in atherosclerosis

OBJECTIVES: Herein, we determined the significance of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) in atherosclerotic vascular disease. BACKGROUND: Inflammation is associated with the pathogenesis of atherosclerosis. The TNF-related apoptosis-inducing ligand/APO-2L, a member of the TNF superfamily, has a role in apoptosis induction and is recognized for its immunomodulatory properties. METHODS: Stable and vulnerable atherosclerotic human plaques and aortas from atherosclerotic mice were assayed for the presence of TRAIL, and its inducibility was assayed by immunoblot and real-time polymerase chain reaction on peripheral mononuclear cells incubated with oxidized low-density lipoprotein (oxLDL). Enzyme-linked immunosorbent assay was used for the determination of soluble TRAIL levels in atherosclerotic patients. RESULTS: Tumor necrosis factor-related apoptosis-inducing ligand is present in stable atherosclerotic lesions, is increased in vulnerable plaques, and is found to colocalize with CD3 cells and oxLDL. The TNF-related apoptosis-inducing ligand messenger ribonucleic acid (mRNA) and protein expression was up-regulated in peripheral blood mononuclear cells after incubation with oxLDL. Serum levels of soluble TRAIL but not TNF-alpha or Fas-ligand were reduced significantly in patients with unstable angina as compared with patients with stable atherosclerotic disease and healthy subjects. A negative correlation was demonstrated between soluble TRAIL and C-reactive protein levels but not with levels of mRNA of TRAIL in peripheral blood mononuclear cells. CONCLUSIONS: Tumor necrosis factor-related apoptosis-inducing ligand is expressed in plaque-infiltrating CD3 cells and induced by oxLDL, whereas levels of soluble TRAIL are reduced in patients with acute coronary syndromes and negatively correlate with C-reactive protein levels. These results support a possible role for TRAIL in atherosclerosis.     

Actinomycin D renders cultured synovial fibroblasts susceptible to tumour necrosis factor related apoptosis-inducing ligand (TRAIL)-induced apoptosis

OBJECTIVE: To investigate the expression of tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) receptors in cultured synovial fibroblasts from rheumatoid arthritis (RA) and osteoarthritis (OA) patients, and to examine their susceptibility to TRAIL-induced apoptosis in the presence or absence of metabolic inhibitors. METHODS: The expression of TRAIL receptors in synovial fibroblasts was examined by Western blot and immunohistochemistry. Expression of TRAIL-receptor 1 (TRAIL-R1), FLICE-inhibitory protein (Fas-associating protein with death domain-like interleukin-1-converting enzyme), and Bcl-2 was assessed by Western blot. Synovial cell viability was measured by 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay (XTT), and apoptosis was determined both by DNA content analysis after propidium iodide staining and Annexin V stain. RESULTS: TRAIL-R1 was constitutively expressed on cultured synovial fibroblasts from RA and OA, however, expression of TRAIL-R2 and TRAIL-R3 was not observed by immunohistochemistry and Western blot. Cultured synovial fibroblasts were resistant to apoptosis by TRAIL alone, but combined treatment of TRAIL with actinomycin D (ActD: 200 ng/mL), cycloheximide (CHX: 10 microg/mL), or proteasome inhibitor (MG132: 20 microM) induced apoptosis in a dose-dependent manner. The apoptosis was completely or partially inhibited by various caspase inhibitors, implicating an involvement of caspase pathway in TRAIL-induced apoptosis in the presence of these metabolic inhibitors. Expression of TRAIL-R1, FLIPL, and Bcl-2 did not account for the apoptosis by the combined treatment of TRAIL with ActD. CONCLUSIONS: Although TRAIL-R1 was constitutively expressed; cultured synovial fibroblasts were resistant to apoptosis by TRAIL. ActD, CHX, and MG132 rendered cultured synovial fibroblasts susceptible to TRAIL-induced apoptosis by a caspase-dependent mechanism. However, the exact mechanism of sensitization by these metabolic inhibitors remains to be determined.     

Tumour necrosis factor related apoptosis inducing ligand (TRAIL) induces hepatic steatosis in viral hepatitis and after alcohol intake

BACKGROUND AND AIMS: Tumour necrosis factor related apoptosis inducing ligand (TRAIL) induces apoptosis in transformed cells and is considered as an agent for cancer therapy. As there is evidence that TRAIL is also essential for apoptosis in animal models of liver injury, we investigated the role of TRAIL in viral hepatitis and after alcohol consumption. METHODS: Expression of TRAIL was determined by western blot analysis in the liver of patients with chronic hepatitis C virus (HCV) infection as well as in experimental acute adenoviral hepatitis and after alcohol intake in the liver of mice. To investigate the effect of FasL and TRAIL expression, we used low dose adenoviral gene transfer. Apoptosis and steatosis were assessed by TUNEL and fat red staining, and by caspase assays. RESULTS: TRAIL was overexpressed in the liver of patients with HCV associated steatosis while acute adenoviral hepatitis resulted in upregulation of TRAIL-DR5. In contrast with FasL, TRAIL expression was harmless to healthy livers. However, in virally infected livers, TRAIL expression induced apoptosis and steatosis whereas expression of FasL only resulted in apoptosis of hepatocytes without steatosis. After alcohol intake, TRAIL expression led to hepatic steatosis, without apoptosis of hepatocytes, indicating that TRAIL mediated apoptosis and steatosis may be independently modulated after viral infection and alcohol intake. In viral hepatitis and after alcohol intake, Ad-TRAIL mediated steatosis can be inhibited by injection of a neutralising TRAIL antibody. CONCLUSIONS: We identified TRAIL as a new mediator of hepatic steatosis in viral hepatitis and after alcohol intake. Consequently, TRAIL mediated hepatotoxicity has to be considered in patients with viral hepatitis and alcoholic liver disease.     

Regulation of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in Burkitt's lymphoma cell lines

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent inducer of apoptosis in sensitive cells and may be suitable for novel anti-cancer therapies aimed at inducing apoptosis via the activation of TRAIL receptors on malignant cells. Here we have characterized the TRAIL sensitivity of a panel of Burkitt's lymphoma (BL) cell lines. Overall, 5/12 BL cell lines and 1/2 lymphoblastoid cell lines were sensitive to TRAIL-induced apoptosis, although only one BL cell line approached the sensitivity of Jurkat cells, a widely used model for TRAIL-induced apoptosis. Whereas, 4/5 of the Epstein-Barr virus (EBV)-negative cell lines were TRAIL sensitive, only 1/7 EBV-positive BL cell lines were TRAIL sensitive. However, isogenic BL cell lines with different EBV status were not differently sensitive to TRAIL, indicating that EBV is not a major determinant of TRAIL sensitivity. All cell lines expressed the death receptor (DR)5 TRAIL receptor, whereas expression of DR4 was more variable. Differences in the expression of downstream signalling molecules [Fas-associated death domain protein (FADD), caspase 8] and inhibitors [decoy receptor 1 (DcR1), cellular FLICE-like inhibitory protein (c-FLIP)] did not correlate with TRAIL sensitivity. Therefore, a subset of BL cell lines are sensitive to TRAIL-induced apoptosis, however, the molecular mechanism that determines responsiveness remains to be identified.     

Identification of tumor necrosis factor-alpha-related apoptosis-inducing ligand (TRAIL) and its receptors in adult rat ventral prostate

Tumor necrosis factor-alpha-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor-alpha (TNF-alpha) family of cytokines that is known to induce apoptosis upon binding to its death domain-containing receptors, DR4/TRAIL-R1 and DR5/TRAIL-R2. Two additional TRAIL receptors, DcR1/TRAIL-R3 and DcR2/TRAIL-R4, lack functional death domains and act as decoy receptors for TRAIL. In this study, the presence of TRAIL and its receptors was investigated in adult rat hormonosensitive ventral prostate. TRAIL and its receptors were identified in the rat ventral prostate in terms of protein and mRNA. TRAIL and its receptors were immunolocalized in prostatic epithelial cells.     

Expression of tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) receptors and sensitivity to TRAIL-induced apoptosis in primary B-cell acute lymphoblastic leukaemia cells

Because tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) (Apo2 ligand) preferentially kills malignant cells while sparing normal cells, it may be therapeutically useful against cancers, including those of haematopoietic origin. Although the activity of TRAIL has been studied in tumour cell lines and in a limited number of different primary tumours, its overall activity in a large number of uniform cases of primary tumours is not known. We therefore studied the activity of TRAIL in 29 primary precursor B-cell acute lymphoblastic leukaemia (ALL) samples. TRAIL was found to have a modest activity as it killed a maximum of 29% of ALL cells within 18 h compared with killing 75% of Jurkat cells. The sensitivity to TRAIL did not correlate with the pattern of TRAIL receptor expression or FLIP expression, as determined by Western blot analysis. The CD40 receptor, which can transduce survival signals in mature malignant B cells, was less frequently expressed on ALL cells, but incubation with an exogenous soluble CD40 ligand trimer did not rescue them from spontaneous apoptosis and did not mediate their resistance to TRAIL. Further, although ALL cells expressed TRAIL protein, they failed to kill target Jurkat cells in a TRAIL-dependent manner. Our data delineate major biological differences between mature and precursor malignant B cells and suggest a limited therapeutic role for TRAIL as a single agent in primary B-cell ALL.     

脂多糖提高巨噬细胞可溶性肿瘤坏死因子相关凋亡诱导配体的表达并诱导肝细胞凋亡

目的探讨脂多糖(LPS)、巨噬细胞表达肿瘤坏死因子相关凋亡诱导配体(TRAIL)和肝细胞凋亡的相互关系。方法LPS刺激巨噬细胞后,以流式细胞仪测定细胞表面的TRAIL表达,用酶联免疫吸附法(ELISA)法检测培养上清中可溶性TRAIL的表达;以(?)铬释放试验测定可溶性TRAIL和膜性TRAIL 对HepG2细胞的毒性作用,并用Annexin V染色法验证凋亡细胞的产生。结果经100 ng/ml LPS刺激后, 只有9.8%的巨噬细胞有TRAIL的表达,而培养上清中可溶性TRAIL达(67.4±5.1)ng/ml,有明显增加。巨噬细胞培养上清液中可溶性TRAIL能溶解HepG2细胞,经Annexin V染色法证实为细胞凋亡,此作用可被特异性TRAIL抗体阻断。结论LPS能增加巨噬细胞可溶性TRAIL表达,并诱导肝细胞凋亡,提示TRAIL在病毒性肝炎发病机制中有重要作用。     

Hepatitis B virus enhances tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity by increasing TRAIL-R1/death receptor 4 expression

BACKGROUND/AIMS: Apoptosis by death receptors, such as Fas and tumor necrosis factor (TNF)-alpha receptor-1, play a significant role in the pathogenesis of hepatitis B virus (HBV)-infections. Although liver also expresses death receptors for TNF-related apoptosis-inducing ligand (TRAIL), information is lacking regarding the effects of HBV on apoptosis by TRAIL. Thus, the aims of this study were to examine the effects of HBV replication on TRAIL cytotoxicity. METHODS: Hep G2 and Hep G2.215 cells, the latter which is stably transfected with HBV, were employed for these studies. RESULTS: TRAIL-mediated cell killing was concentration-dependent and greater in Hep G2.2.15 cells at all doses as compared to the parent cell line, Hep G2 cells. Cell death by apoptosis was confirmed by demonstrating caspase activation and inhibition of cell killing by a caspase inhibitor, zVAD-fmk. TRAIL-R1/DR4 protein expression was enhanced in Hep G2.2.15 cells as compared to Hep G2 cells. Lamivudine treatment reduced TRAIL-mediated apoptosis and TRAIL-R1/DR4 expression in Hep G2.2.15 cells. In Hep G2 cells transfected with the HBV-encoded X antigen (HBxAg), sensitivity to TRAIL-mediated apoptosis and TRAIL-R1/DR4 expression were both increased. CONCLUSIONS: TRAIL-induced apoptosis is enhanced by the level of HBV replication in human hepatocytes, in part, by HBxAg-dependent upregulation of TRAIL-R1/DR4.     

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and Fas apoptosis in Burkitt's lymphomas with loss of multiple pro-apoptotic proteins

BACKGROUND AND OBJECTIVES: Normal B-cells in the germinal center (GC) may be exposed to both tumor necrosis factor-related apoptosis inducing ligand (TRAIL) and Fas-L. Whether abrogation of TRAIL apoptosis is a feature in the genesis of B cell lymphomas of GC-phenotype is not known. We assessed the integrity of the TRAIL pathway in Fas-resistant and Fas-sensitive Burkitt s lymphomas (BLs). DESIGN AND METHODS: Expression of TRAIL receptors was determined by flow cytometry and Western blots. The extent of apoptosis following exposure to TRAIL was measured by annexin-V/propidium iodide dual staining. The integrity of the Fas and TRAIL apoptotic pathways was determined by Western blotting to assess cleavage of downstream caspases. Western blot analyses were used to determine the expression of pro- and anti-apoptotic proteins and the profile of expression was correlated with response to TRAIL and CH11. RESULTS. Our results demonstrate that BL expresses both functional and decoy TRAIL receptors. BLs with a functional Fas pathway retained sensitivity to TRAIL. Frequent and compound loss of expression of pro-apoptotic proteins can be identified in BLs resistant to Fas. However, loss of Bax, Bak and Bcl-Xs did not compromise sensitivity to TRAIL. INTERPRETATION AND CONCLUSIONS: Our results indicate that BLs frequently retain sensitivity to the TRAIL pathway. These results underscore the utility of TRAIL-based therapeutic strategies in the treatment of those B-cell lymphomas that may have compromised expression of several pro-apoptotic proteins.     

A novel natural compound, a cycloanthranilylproline derivative (Fuligocandin B), sensitizes leukemia cells to apoptosis induced by tumor necrosis factor related apoptosis-inducing ligand (TRAIL) through 15-deoxy-Delta 12, 14 prostaglandin J2 production

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induces apoptosis in many transformed cells; however, not all human tumors respond to TRAIL, potentially limiting its therapeutic utility. Although there is substantial evidence that cytotoxic drugs can augment sensitivity to TRAIL, it has become important to know what kinds of nontoxic drugs can be used together with TRAIL. We thus screened several natural compounds that can overcome resistance to TRAIL and found that a cycloanthranilylproline derivative, Fuligocandin B (FCB), an extract of myxomycete Fuligo candida, exhibited significant synergism with TRAIL. Treatment of the TRAIL-resistant cell line KOB with FCB and TRAIL resulted in apparent apoptosis, which was not induced by either agent alone. FCB increased the production of 15-deoxy-Delta(12,14) prostaglandin J(2) (15d-PGJ(2)), an endogenous PPAR gamma ligand, through activation of cyclooxygenase-2 (COX-2). This unique mechanism highlighted the fact that 15d-PGJ(2) directly enhanced sensitivity to TRAIL by inhibiting multiple antiapoptotic factors. More importantly, similar effects were observed in other leukemia cell lines irrespective of their origin. The enhancement was observed regardless of PPAR gamma expression and was not blocked even by peroxisome proliferator-activated receptor-gamma (PPAR gamma) siRNA. These results indicate that 15d-PGJ(2) sensitizes TRAIL-resistant cells to TRAIL in a PPAR gamma-independent manner and that the use of 15d-PGJ(2) or its inducers, such as FCB, is a new strategy for cancer therapy.     

Circulating soluble tumor necrosis factor related apoptosis inducing-ligand (TRAIL) is decreased in type-2 newly diagnosed, non-drug using diabetic patients

We examined the association between serum sTRAIL measured by ELISA and HbA1C levels, pre/post-prandial blood glucose levels and body mass index in 22 newly diagnosed type-2 diabetic patients. A significant difference in sTRAIL levels was found between study group and controls.     

Cloning and expression of apoptosis inhibitory protein homologs that function to inhibit apoptosis and/or bind tumor necrosis factor receptor-associated factors.

Baculovirus inhibitors of apoptosis (IAPs) act in insect cells to prevent cell death. Here we describe three mammalian homologs of IAP, MIHA, MIHB, and MIHC, and a Drosophila IAP homolog, DIHA. Each protein bears three baculovirus IAP repeats and an N-terminal ring finger motif. Apoptosis mediated by interleukin 1beta converting enzyme (ICE), which can be inhibited by Orgyia pseudotsugata nuclear polyhedrosis virus IAP (OpIAP) and cowpox virus crmA, was also inhibited by MIHA and MIHB. As MIHB and MIHC were able to bind to the tumor necrosis factor receptor-associated factors TRAF1 and TRAF2 in yeast two-hybrid assays, these results suggest that IAP proteins that inhibit apoptosis may do so by regulating signals required for activation of ICE-like proteases.