Soluble Death Receptor Research Articles

Chemical synthetic approaches to mimic the TRAIL: promising cancer therapeutics.

Apoptosis is programmed cell death that eliminates undesired cells to maintain homeostasis in metazoan. Aberration of this process may lead to cancer genesis. The tumor necrosis factor related apoptosis inducing ligand (TRAIL) induces apoptosis in cancer cells after ligation with death receptors (DR4/DR5) while sparing most normal cells. Therefore, strategies to induce apoptosis in cancer cells by mimicking the TRAIL emerge as a promising therapeutic tool. Hence, approaches are taken to develop TRAIL/DR-based cancer therapeutics. The recombinant soluble TRAIL (rhTRAIL) and death receptor agonistic antibodies were produced and tested pre-clinically and clinically. Pre-clinical and clinical trial data demonstrate that these therapeutics are safe and relatively well tolerated. But some of these therapeutics failed to exert adequate efficacy in clinical settings. Besides these biotechnologically derived therapeutics, a few chemically synthesized therapeutics are reported. Some of these therapeutics exert considerable efficacy in vitro and in vivo. In this review, we will discuss chemically synthesized TRAIL/DR-based therapeutics, their chemical and biological behaviour, design concepts and strategies that may contribute to further improvement of TRAIL/DR-based therapeutics.

Blocking TRAIL-DR5 signaling pathway with soluble death receptor 5 fusion protein mitigates radiation-induced injury.

The increasing application of nuclear technology, the high fatality of acute radiation syndrome (ARS) and its complex mechanism make ARS a global difficulty that requires urgent attention. Here we reported that the death receptor 5 (DR5), as well as its ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), were both significantly upregulated after irradiation in mice with 6 Gy γ-ray single radiation. And by intravenously administrated with soluble DR5 fusion protein (sDR5-Fc), the competitive antagonist of DR5, the excessive apoptosis in the radiation-sensitive tissues such as spleen and thymus were significantly inhibited and the radiation-induced damage of spleen and thymus were mitigated, while the expression of apoptosis-inhibiting proteins such as Bcl-2 was also significantly upregulated. The biochemical indicators such as serum ALP, AST, ALT, TBIL, K, and Cl levels that affected by radiation, were improved by sDR5-Fc administration. sDR5-Fc can also regulate the number of immune cells and reduce blood cell death. For in vitro studies, it had been found that sDR5-Fc effectively inhibited apoptosis of human small intestinal mucosal epithelial cells and IEC-6 cells using flow cytometry. Finally, survival studies showed that mice administrated with sDR5-Fc after 9 Gy γ-ray single whole body radiation effectively increased the 30-day survival and was in a significant dose-dependent manner. Overall, the findings revealed that DR5/TRAIL-mediated apoptosis pathway had played important roles in the injury of ARS mice, and DR5 probably be a potential target for ARS therapeutics. And the DR5 apoptosis antagonist, sDR5 fusion protein, probably is a promising anti-ARS drug candidate which deserves further investigation.

TRAIL inhibition by soluble death receptor 5 protects against acute myocardial infarction in rats.

Acute myocardial infarction (AMI) is associated with high morbidity and mortality. An effective therapeutic strategy is to rescue cardiomyocytes from death. Apoptosis is a key reason of cardiomyocyte death that can be prevented. In this study, we investigated the role of TNF-related apoptosis-inducing ligand (TRAIL) in initiating apoptosis by binding to death receptor 5 (DR5), and this procession is inhibited by soluble DR5 (sDR5) in rats after AMI. First, we found that the level of TRAIL in serum was down-regulated in AMI patients. Then, TRAIL and DR5 expression was analysed in the myocardium of rats after AMI, and their expression was up-regulated. sDR5 treatment reduced the myocardial infarct size and the levels of CK-MB and cTn-I in serum. The expression of caspase 3 and PARP is decreased, but the anti-apoptotic factor Bcl-2 was increased in sDR5 treatment rats after AMI. DR5 expression was also analysed after sDR5 treatment and it was down-regulated, and a low level of DR5 expression seemed to be beneficial for the myocardium. Overall, our findings indicated that sDR5 decreases myocardial damage by inhibiting apoptosis in rat after AMI. We expect to observe the potential therapeutic effects of sDR5 on AMI in the future.

Elevated soluble death receptor 5 can predict poor prognosis in patients with acute respiratory distress syndrome

ABSTRACT Background The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and its receptor, death receptor 5 (DR5), participate in pulmonary cell apoptosis. This study aimed to investigate the clinical value of soluble DR5 and TRAIL for prognosis assessment in acute respiratory distress syndrome (ARDS). Research design and methods Serum and bronchoalveolar lavage fluid (BALF) samples were collected from ARDS patients and controls. Patients were followed-up until death or discharge. Soluble DR5, TRAIL, TNF-α, soluble receptor for advanced glycation end-products (sRAGE), and albumin levels were measured using the Magnetic Luminex or enzyme-linked immunosorbent assays. Data were analyzed according to their distributions and statistical purposes. Results Serum and BALF DR5 levels were elevated in patients with ARDS; TRAIL elevation and reduction was observed in BALF and serum, respectively. Serum DR5 was higher in non-survivors compared to survivors. Serum DR5 was positively correlated with serum TNF-α and critical illness scores and negatively correlated with serum TRAIL. Serum DR5 exhibited potential for predicting mortality in patients with ARDS. Conclusions Serum soluble DR5 elevation, a valuable prognosis predictor in ARDS, may be associated with alveolar epithelial cell apoptosis. Trial Registration http://www.chictr.org.cn/index.aspx.Uniqueidentifier:ChiCTR-DDD-17013370.

SDR5-Fc inhibits macrophage M1 polarization by blocking the glycolysis.

BACKGROUNDM1 polarization of macrophages is an important pathological process in myocardial ischemia reperfusion injury, which is the major obstacle for the treatment of acute myocardial infarction. Currently, the strategies and mechanisms of inhibiting M1 polarization are poorly explored. This study aims to investigate the role of soluble death receptor 5-Fc (sDR5-Fc) in regulating M1 polarization of macrophages under extreme conditions and explore the mechanisms from the aspect of glycolysis.METHODSExtreme conditions were induced in RAW264.7 cells. Real-time quantitative polymerase chain reaction and western blot were used to detect the expression of mRNA and proteins, respectively. Cell counting kit-8 was used to investigate the proliferation activity of cells. Expression levels of inflammatory cytokines were determined by enzyme-linked immunosorbent assay.RESULTSWe found that sDR5-Fc rescues the proliferation of macrophages under extreme conditions, including nutrition deficiency, excessive peroxide, and ultraviolet irradiation. In addition, administration of sDR5-Fc inhibits the M1 polarization of macrophages induced by lipopolysaccharide (LPS) and interferon-gamma (IFN-γ), as the expression of M1 polarization markers CD86, CXC motif chemokine ligand 10, matrix metalloproteinase 9, and tumor necrosis factor-α, as well as the secretion of inflammatory factors interleukin (IL)-1β and IL-6, were significantly decreased. By further investigation of the mechanisms, the results showed that sDR5-Fc can recover the LPS and IFN-γ induced pH reduction, lactic acid elevation, and increased expression of hexokinase 2 and glucose transporter 1, which were markers of glycolysis in macrophages.CONCLUSIONSsDR5-Fc inhibits the M1 polarization of macrophages by blocking the glycolysis, which provides a new direction for the development of strategies in the treatment of myocardial ischemia reperfusion injury.

Preclinical studies of a death receptor 5 fusion protein that ameliorates acute liver failure.

Acute liver failure (ALF) is a life-threatening disease with a high mortality rate. There is an urgent need to develop new drugs with high efficacy and low toxicity. In this study, we produced a pharmaceutical-grade soluble death receptor 5 (sDR5)-Fc fusion protein for treating ALF and evaluated the pharmacology, safety, pharmacokinetics, efficacy, and mechanisms of sDR5-Fc in mice, rats, and cynomolgus monkeys. sDR5-Fc bound with high affinity to both human and monkey tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) effectively blocked TRAIL-induced apoptosis in vitro and significantly ameliorated ALF induced by concanavalin A (Con A) in mice. Mechanistically, sDR5-Fc inhibited hepatocyte death and reduced inflammation in vivo. Furthermore, sDR5-Fc attenuated the production of inflammatory cytokines by splenocytes activated with Con A or an anti-CD3 antibody in vitro. Consistent with these results, splenocytes from TRAIL-/- mice produced much lower levels of inflammatory cytokines than those from TRAIL+/+ mice. In cynomolgus monkeys, sDR5-Fc was safe and well tolerated when intravenously administered as a single dose of up to 1200mg/kg or multiple doses of 100mg/kg. After treatment with a single dose, linear pharmacokinetics with a mean half-life of > 1.9days were observed. After 12 weekly doses, sDR5-Fc exposure increased in an approximately dose-proportional manner, and the mean accumulation ratio ranged from 1.82- to 2.11-fold. These results support further clinical development of our sDR5-Fc protein as the first TRAIL-targeting drug for ALF treatment. KEY MESSAGES: sDR5-Fc binds with high affinity to TRAIL to effectively block TRAIL-induced apoptosis. sDR5-Fc ameliorates Con A-induced acute liver failure in mice by inhibiting hepatocyte death and inflammation. sDR5-Fc or TRAIL knockout attenuates the production of inflammatory cytokines by activated splenocytes in vitro. sDR5-Fc is safe and well tolerated in acute or long-term toxicity study.

Prognostic significance of serum soluble DR5 levels in small-cell lung cancer.

The death receptor 5 (DR5) is a member of the tumor necrosis factor receptor superfamily that can transduce the apoptosis signal in cells. This study assessed serum levels of soluble death receptor 5 (sDR5) in small-cell lung cancer (SCLC) patients compared with those in healthy controls. Clinicopathological features of patients, treatment responses, and overall survival of patients were also recorded and analyzed. The sDR5 levels were analyzed using ELISA in 50 healthy controls and 82 SCLC patients before and after first-line chemotherapy. The statistical data showed that pre-treatment levels of serum sDR5 in SCLC patients were higher than those of healthy controls (P<0.001). Pre-treatment levels of serum sDR5 were significantly associated with smoking history of patients, Veterans Administration Lung Study Group (VALSG) stage, tumor size, and lymph node (N) metastasis (P=0.028, 0.001, 0.028, and 0.01, respectively). After treatment with the first-line chemotherapy, the post-treatment levels of serum sDR5 were obviously decreased (P<0.001), and correlated with treatment responses (P<0.001), although there was no significant difference in their pretreatment sDR5 levels (P=0.62). Cox proportional hazard analysis demonstrated that the post-treatment levels of serum sDR5, VALSG stage, and PS status were all independent predictors for overall survival of patients. The results from the current study indicate that serum level of sDR5 could be further confirmed as a biomarker to predict treatment responses and survival of SCLC patients.

Prognostic Value of Soluble Death Receptor Ligands in Patients with Transitional Cell Carcinoma of Bladder

Background: The activation of Fas/Fas ligand (FasL) and DR4-DR5/tumor necrosis factor-related-apoptosis-inducing ligand (TRAIL) pathways in cancer cells triggers apoptosis. The objective of this study was to investigate the prognostic value of soluble FasL (sFasL) and soluble (sTRAIL) in the serum of patients with bladder cancer. Methods: The sFasL and sTRAIL levels in the sera of patients with bladder cancer or healthy donors were determined using the enzyme-linked immunosorbent assay. Micro-culture tetrazolium viability assay and Western blot were used to analyze cell cytotoxicity and death receptors protein expression respectively. Results: Whether no difference in sTRAIL levels was seen between patients and controls, the level of sFasL was higher in patients than that in healthy donors. According to, sFasL level was the highest in the serum of patients with superficial stage or low- and medium-grade cancer. Moreover, sFasL in patients with superficial noninvasive bladder tumors or low- and medium-grade cancers was higher than that in patients with invasive carcinomas and high-grade cancers. Patients with high levels of sFasL survive longer than those with low levels, probably related to the cytotoxic potential of FasL preserved in its soluble form. Conclusion: The data suggest that monitoring the level of sFasL and its cytotoxic activity could be a prognostic marker in the follow-up of patients with bladder cancer.

Elevated Markers of Death Receptor-Activated Apoptosis are Associated with Increased Risk for Development of Diabetes and Cardiovascular Disease

BackgroundAn increased rate of cell death by apoptosis has been implicated in both diabetes and atherosclerosis. Apoptosis can be induced through activation of the death receptors TNF receptor 1 (TNFR-1), TRAIL receptor 2 (TRAILR-2) and Fas. Soluble forms of these receptors are found in plasma. The objective of this study was to determine if soluble death receptors are markers of receptor-activated apoptosis and predict risk for development of diabetes and cardiovascular events. MethodsFas ligand was used to induce apoptosis in peripheral blood mononuclear cells and INS-1 pancreatic β-cells and release of TNFR-1, TRAILR-2 and Fas measured by ELISA. Proximity Extension Assay was used to analyze plasma levels of TNFR-1, TRAILR-2 and Fas in baseline samples of 4742 subjects in the Malmö Diet and Cancer Study and related to development of diabetes and cardiovascular events during 19.2years of follow-up. ResultsActivation of apoptosis by Fas ligand was associated with release of soluble Fas, TNFR-1 and TRAILR-2 in both cell types. Circulating levels of all three receptors were higher in subjects with diabetes and correlated with markers of impaired glucose metabolism in non-diabetic subjects. Among the latter, those in the highest tertile of soluble Fas, TNFR-1 and TRAILR-2 had increased risk for development of diabetes and cardiovascular events. These associations became weaker when adjusting for cardiovascular risk factors in Cox regression models, but remained significant for TRAILR-2 with incident diabetes, cardiovascular mortality, myocardial infarction and ischemic stroke, and for TNFR-1 with myocardial infarction. ConclusionThe present study demonstrates an association between several cardiovascular risk factors and elevated levels of circulating markers of apoptotic cell death. It also shows that subjects with high levels of these biomarkers have increased risk of diabetes and CVD. This implies that soluble death receptors are markers of β-cell and vascular injury and potentially could be used as surrogate markers of therapeutic efficiency in risk factor interventions.

Clinical significance of serum soluble death receptor 5 concentration in locally advanced non-small cell lung cancer patients.

There is an urgent requirement for the identification of suitable biomarkers for the diagnosis and prognosis of non-small cell lung cancer (NSCLC). The present study aimed to measure the levels of serum soluble death receptor 5 (sDR5) in patients with locally advanced stage III NSCLC, and to evaluate its diagnostic and prognostic significance in these patients. The sDR5 concentrations were evaluated by the enzyme-linked immunosorbent assay method in 50 healthy controls and 122 patients with locally advanced stage III NSCLC [including 57 adenocarcinoma (ADC) and 65 squamous cell carcinoma (SCC) patients], before and after concurrent chemoradiotherapy. It was found that the pretreatment sDR5 levels in patients with NSCLC were higher than the sDR5 levels of healthy controls (P<0.001). However, no significant difference in the sDR5 levels was observed between the ADC and SCC subgroups (P=0.874). According to multiple clinical classifications, a significant increase in the pretreatment serum sDR5 levels could be observed in IIIB-stage patients compared with IIIA-stage patients (P=0.009). Patients with a tumor burden >3 cm had higher pretreatment sDR5 concentration than those with a tumor burden ≤3 cm (P=0.026). Additionally, T4-stage patients had significantly higher pretreatment sDR5 levels compared with those of T1-stage patients (P<0.001). There were no significant differences between pre- and post-treatment sDR5 concentrations in the total NSCLC patient group (P=0.462), ADC subgroup (P=0.066) and SCC subgroup (P=0.052). Furthermore, when patients were divided according to therapeutic response, the pretreatment sDR5 levels in the responder patients were significantly lower compared with those of the non-responders (P<0.001). Further survival analysis showed that the patients whose pretreatment sDR5 levels were ≤14 pg/ml (cutoff value, 14 pg/ml) had a longer progression-free survival (PFS) time than patients with sDR5 levels >14 pg/ml. However, no correlation was observed between the post-treatment sDR5 levels and therapeutic response or PFS time. To the best of our knowledge, the present study results provide the first evidence that the pretreatment serum levels of sDR5 may be a useful biomarker for the diagnosis, prediction and prognosis of patients with locally advanced stage III NSCLC.

Differential induction of activation and apoptosis by TCR signaling in sooty mangabeys and rhesus macaques

Background We previously showed that an increase in CD4+ T lymphocyte apoptosis and elevation of plasma tumor necrosisreceptor associated apoptosis-inducing ligand (TRAIL) occurs in rhesus macaques (RM) but not sooty mangabeys (SM) during acute SIV infection. Methods To further examine the mechanisms underlying differential apoptosis in SIV-infected RM and SM, we compared the in vitro responses to TCR signaling in seven SIVnegative SM and seven SIV-negative RM. PBMC were cultured for 18 hours with cross-linked CD3 and CD28 and subsequently analyzed by flow cytometry for upregulation of CD69, TRAIL and active Caspase 3, and for production of cytokines. Results Following TCR stimulation, there was a significant increase in TRAIL on T cell subsets, NK cells and myeloid DC cells (mDCs) in both species. However, levels of membrane TRAIL were significantly higher in CD8+ T lymphocytes and NK cells of SM compared to RM suggesting that they may be more cytotoxic on activation. TCR stimulation also resulted in an upregulation of CD69 and production of IFNg ,I L-2 and TNFa by T cell subsets in both species with greater levels being observed in SM. In contrast to SM, RM showed significantly higher frequencies of apoptotic mDCs both ex vivo and following TCR stimulation. In vivo inoculation of RM with SIVmac239 resulted in increased frequency of ex vivo apoptotic mDCs at 2-3 weeks post-infection. Increased apoptosis was also observed after overnight culture in medium but was abrogated by addition of soluble death receptor 5 indicating that it was TRAILmediated.

Serum soluble death receptor 5 concentration in patients with chronic hepatitis B is associated with liver damage and viral antigen level

To measure the levels of serum soluble death receptor 5 (sDR5) in patients with hepatitis B. sDR5 concentration in 60 HBV infected patients and 30 healthy volunteers were measured by ELISA. sDR5 concentration in the HBV infected patients was decreased and correlated with serum ALT, Tbil level, albumin/globulin ratio and HBV antigen level. Decreased serum sDR5 is associated with high level of liver damage and inhibited HBV antigen expression.

Activation of p38 MAPK by damnacanthal mediates apoptosis in SKHep 1 cells through the DR5/TRAIL and TNFR1/TNF-α and p53 pathways

The effect of the natural compound damnacanthal from Morinda citrifolia on SKHep 1 cell growth regulation was investigated. Treatment of SKHep 1 cells with damnacanthal for 24 h indicated a dose-dependent antiproliferative activity. Damnacanthal seems to be selective for tumor cell lines, since there is only minimal toxicity against normal hepatocyte cells (FL83B). This is first demonstration that damnacanthal-mediated apoptosis involves the sustained activation of the p38 MAPK pathway, leading to the transcription of the death receptor family genes encoding DR5/TRAIL and TNF-R1/TNF-α genes as well as the p53-regulated Bax gene. The damnacanthal-mediated expression of DR5/TRAIL and TNF-R1/TNF-α results in caspase 8 activation, leading to Bid cleavage. In turn, activated Bid, acting with p53-regulated Bax, leads to cytochrome c released from mitochondria into the cytoplasm. Combined activation of the death receptors and mitochondrial pathways results in activation of the downstream effecter caspase 3, leading to cleavage of PARP. TRAIL- and TNF-α-mediated damnacanthal-induced apoptosis could be suppressed by treatment with caspase inhibitors as well as soluble death receptors Fc:DR5 and Fc:TNF-R1 chimera. Taken together, this study provided first evidence demonstrating that TRAIL-, TNF-α-, and p53-mediated damnacanthal-induced apoptosis require the activation of p38 MAPK and mitochondrion-mediated caspase-dependent pathways.

Critical Role for Death-Receptor Mediated Apoptotic Signaling in Viral Myocarditis

BackgroundApoptosis of cardiac myocytes plays a key role in the pathogenesis of many cardiac diseases, including viral myocarditis. The apoptotic signaling pathways that are activated during viral myocarditis and the role that these pathways play in disease pathogenesis have not been clearly delineated. Methods and ResultsWe investigated the role of apoptotic signaling pathways after virus infection of primary cardiac myocytes. The death receptor–associated initiator caspase, caspase 8, and the effector caspase, caspase 3, were significantly activated after infection of primary cardiac myocytes with myocarditic, but not non-myocarditic, reovirus strains. Furthermore, reovirus-induced cardiac myocyte apoptosis was significantly inhibited by soluble death receptors. In contrast, the mitochondrial membrane potential remained unaltered and caspase 9, the initiator caspase associated with mitochondrial apoptotic signaling, was only weakly activated in cardiac myocytes after infection with myocarditic reovirus strains. Inhibition of mitochondrial apoptotic signaling had no effect on reovirus-induced cardiac myocyte apoptosis. In accordance with our in vitro data, caspase 8, but not caspase 9, was significantly activated in the hearts of reovirus-infected mice. ConclusionsDeath receptor, but not mitochondrial, apoptotic signaling plays a key role in apoptosis after infection of cardiac myocytes with myocarditic reovirus strains.

A Genetically Encoded Multifunctional TRAIL Trimer Facilitates Cell-Specific Targeting and Tumor Cell Killing

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL, Apo2L) has been shown to exhibit potent and specific apoptotic activity against tumor cells. Several TRAIL constructs have been tried in patients, and the molecule remains under active clinical investigation. Native and recombinant TRAIL must form a homotrimer to become biologically active. However, noncovalently associated TRAIL displays a high degree of sensitivity to degradation, which limits its therapeutic potential. To enforce trimerization of the recombinant protein, we developed a covalently linked TRAIL trimer (TR3) by genetic fusion. This molecular drug design conferred improved stability without altering the native killing ability of TRAIL. Target specificity was shown by blocking TR3 activity with soluble death receptor 5 (DR5-Fc). In addition, we have shown that TR3 is amenable to further, genetic modifications. The incorporation of additional functional domains to TR3, such as antibody fragments (scFvs) that allow for a more cell-specific delivery of the agent, is stoichiometrically controlled and inconsequential with regard to the bioactivity of TRAIL. As proof of this concept, TR3 activity was targeted to the mouse RBC membrane. TR3-decorated RBCs were effectively capable of target cell killing in a model of pancreatic cancer. TR3 represents a generally applicable platform tool to study basic mechanisms along the death receptor pathway. More importantly, the ability to target TR3 to a cell surface presents the opportunity to create a cancer-selective drug with fewer off-target toxicities and enhanced killing capacities.

Bovine ephemeral fever virus-induced apoptosis requires virus gene expression and activation of Fas and mitochondrial signaling pathway

Although induction of apoptosis by bovine ephemeral fever virus (BEFV) in several cell lines has been previously demonstrated by our laboratory, less information is available on the process of BEFV-induced apoptosis in terms of cellular pathways and specific proteins involved. In order to determine the step in viral life cycle at which apoptosis of infected cells is triggered, chemical and physical agents were used to block viral infection. Treatment of BHK-21 infected cells with ammonium chloride (NH4Cl) or cells infected with UV-inactivated BEFV was seen to abrogate virus apoptosis induction, suggesting that virus uncoating and gene expression are required for the induction of apoptosis. Using soluble death receptors Fc:Fas chimera to block Fas signaling, BEFV-induced apoptosis was inhibited in cells. BEFV infection of BHK-21 cells results in the Fas-dependent activation of caspase 8 and cleavage of Bid. This initiated the dissipation of the membrane potential and the release of cytochrome c but not AIF or Smac/DIABLO from mitochondrial into cytoplasm leading to activation of caspase 9. Combined activation of the death receptor and mitochondrial pathways results in activation of the downstream effecter caspase 3 leading to cleavage of PARP. Fas-mediated BEFV-induced apoptosis could be suppressed by the overexpression of Bcl-2 or by treatment with caspase inhibitors and soluble death receptors Fc:Fas chimera. Taken together, this study provided first evidence demonstrating that BEFV-induced apoptosis requires viral gene expression and occurs through the activation of Fas and mitochondrion-mediated caspase-dependent pathways.

Reduced apoptosis induced by endotoxin in mice blocking TRAIL with soluble death receptor 5

Objective To explore the effect of TNF related apoptosis inducing ligand (TRAIL) in apoptosis induced by LPS. Methods After LPS injected mice blocking TRAIL with soluble death receptor 5 (sDRS), detecting ALT, AST and LDH of mice serum at different times, apoptotic effects of LPS to mice hepatocyte were detected by HE and flow eytometry (FCM) with Annexin V-FITC/PI staining. The expres-sion of DR5 in mice hepatocyte was assayed with immunohistochemistry and FCM. Results Apoptotic effect was promoted by up-regulated DR5 expression on hepatocyte. Blocking TRAIL with sDR5 markedly amelio-rated the hepatocyte damage and reduced apoptosis. Conclusion These results establish a critical role for TRAIL in apoptosis during disease process of LPS. Key words: Endotoxin; Lipopolysaccharides; Soluble death receptor 5 ; TNF related apoptosis inducing ligand; Hepatocyte apoptosis

Immune parameters as markers of tuberculosis extent of disease and early prediction of anti-tuberculosis chemotherapy response

This study investigates how the extent of pre-treatment radiological disease and early anti-tuberculous treatment response affect levels of selected circulating host immune markers. Twenty HIV-uninfected tuberculosis patients with BACTEC culture positivity for Mycobacterium tuberculosis at diagnosis and treated with directly observed short course anti-tuberculosis chemotherapy and 13 healthy community controls were enrolled. Serum samples were collected throughout treatment. After the intensive phase of treatment, 12 patients remained sputum culture-positive (slow responders) and eight patients were culture negative (fast responders). C-reactive protein (CRP), soluble intercellular adhesion molecule-1 (sICAM-1), soluble urokinase plasminogen activator receptor (suPAR), soluble lymphocyte activation gene-3 (sLAG-3), granzyme B, soluble tumour necrosis factor receptor one and two (sTNFR I and sTNFR II) and soluble death receptor 5 (sDR5) concentrations were measured. High levels of CRP at diagnosis were found to be associated (p</=0.05) with the presence of multiple cavities on chest x-rays and high levels of suPAR and sICAM-1 at diagnosis were associated (p</=0.05) with the extent of alveolar disease. Also significant were the associations between the level of granzyme B (p</=0.01) and LAG-3 (p</=0.05) at diagnosis, and the size of the cavities. The combination of diagnosis and week one measurements of selected serological markers in mathematical models was able to identify the fast responders with up to 87.5% accuracy and the slow responders with up to 83.3% accuracy These preliminary results suggest that predictive models for differential early treatment responses using combinations of host markers hold promise.

Atorvastatin does not alter serum levels of sCD95 and sCD95L in multiple sclerosis

Elimination of autoreactive T cells by apoptosis is critical for restricting immune responses to self-antigens. An errant lytic interaction between the CD95 death receptor and its ligand CD95L is presumed to be involved in the pathogenesis of multiple sclerosis (MS). Statins are promising agents for the treatment of MS and were shown to modulate levels of soluble death receptors. Here, we evaluated the in vivo effects by interferon (IFN)-beta and atorvastatin on soluble CD95 (sCD95) and sCD95L in serum of patients with MS. Concentrations of sCD95 and sCD95L did not show any differences between MS and healthy control subjects. In patients with MS, treatment with IFN-beta increased serum levels of sCD95 and sCD95L significantly (P < 0.01 and P < 0.05 respectively). Addition of atorvastatin to IFN-beta did not alter serum levels of sCD95 and sCD95L significantly. Our study suggests that atorvastatin does not affect IFN-beta-induced increases of the soluble death receptors in the serum of patients with MS.

Blockade of TRAIL pathway ameliorates HBV-induced hepatocyte apoptosis in an acute hepatitis model

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) may play important roles during hepatitis B virus (HBV) infection. In this study, we used a recombinant human soluble death receptor 5 (sDR5) to explore its effect in a mouse model of HBV-induced acute hepatitis. By measuring blood transaminase activity and hepatocyte apoptosis, we found that sDR5 could alleviate liver damage by blocking TRAIL-induced apoptosis of HBV-transfected hepatocytes. sDR5 injection at 16mg/kg 24h before HBV transfection was the most effective. Additionally, we showed that sDR5 was equally effective in protecting liver injury as the Stronger Neo-Minophagen C (SNMC), a commonly used drug for patients with liver diseases. Thus, sDR5 represents a potential novel therapeutic drug for patients with fulminant hepatitis.