Tumor necrosis factor-related apoptosis-inducing ligand and CD56 expression in patients with type 1 diabetes mellitus

Repositioning the Role of Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) on the TRAIL to the Development of Diabetes Mellitus: An Update of Experimental and Clinical Evidence

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF protein superfamily, represents a multifaceted cytokine with unique biological features including both proapoptotic and pro-survival effects in different cell types depending on receptor interactions and local stimuli. Beyond its extensively studied anti-tumor and immunomodulatory properties, a growing body of experimental and clinical evidence over the past two decades suggests a protective role of TRAIL in the development of type 1 (T1DM) and type 2 (T2DM) diabetes mellitus. This evidence can be briefly summarized by the following observations: (i) acceleration and exacerbation of T1DM and T2DM by TRAIL blockade or genetic deficiency in animal models, (ii) prevention and amelioration of T1DM and T2DM with recombinant TRAIL treatment or systemic TRAIL gene delivery in animal models, (iii) significantly reduced circulating soluble TRAIL levels in patients with T1DM and T2DM both at disease onset and in more advanced stages of diabetes-related complications such as cardiovascular disease and diabetic nephropathy, (iv) increase of serum TRAIL levels in diabetic patients after initiation of antidiabetic treatment and metabolic improvement. To explore the underlying mechanisms and provide mechanistic links between TRAIL and diabetes, a number of animal and in vitro studies have reported direct effects of TRAIL on several tissues involved in diabetes pathophysiology such as pancreatic islets, skeletal muscle, adipose tissue, liver, kidney, and immune and vascular cells. Residual controversy remains regarding the effects of TRAIL on adipose tissue homeostasis. Although the existing evidence is encouraging and paves the way for investigating TRAIL-related interventions in diabetic patients with cardiometabolic abnormalities, caution is warranted in the extrapolation of animal and in vitro data to the clinical setting, and further research in humans is imperative in order to uncover all aspects of the TRAIL-diabetes relationship and delineate its therapeutic implications in metabolic disease.

TRAIL, OPG, and TWEAK in kidney disease: biomarkers or therapeutic targets?

Ligands and receptors of the tumor necrosis factor (TNF) superfamily regulate immune responses and homeostatic functions with potential diagnostic and therapeutic implications. Kidney disease represents a global public health problem, whose prevalence is rising worldwide, due to the aging of the population and the increasing prevalence of diabetes, hypertension, obesity, and immune disorders. In addition, chronic kidney disease is an independent risk factor for the development of cardiovascular disease, which further increases kidney-related morbidity and mortality. Recently, it has been shown that some TNF superfamily members are actively implicated in renal pathophysiology. These members include TNF-related apoptosis-inducing ligand (TRAIL), its decoy receptor osteoprotegerin (OPG), and TNF-like weaker inducer of apoptosis (TWEAK). All of them have shown the ability to activate crucial pathways involved in kidney disease development and progression (e.g. canonical and non-canonical pathways of the transcription factor nuclear factor-kappa B), as well as the ability to regulate cell proliferation, differentiation, apoptosis, necrosis, inflammation, angiogenesis, and fibrosis with double-edged effects depending on the type and stage of kidney injury. Here we will review the actions of TRAIL, OPG, and TWEAK on diabetic and non-diabetic kidney disease, in order to provide insights into their full clinical potential as biomarkers and/or therapeutic options against kidney disease.

Gene expression signature predicts human islet integrity and transplant functionality in diabetic mice

There is growing evidence that transplantation of cadaveric human islets is an effective therapy for type 1 diabetes. However, gauging the suitability of islet samples for clinical use remains a challenge. We hypothesized that islet quality is reflected in the expression of specific genes. Therefore, gene expression in 59 human islet preparations was analyzed and correlated with diabetes reversal after transplantation in diabetic mice. Analysis yielded 262 differentially expressed probesets, which together predict islet quality with 83% accuracy. Pathway analysis revealed that failing islet preparations activated inflammatory pathways, while functional islets showed increased regeneration pathway gene expression. Gene expression associated with apoptosis and oxygen consumption showed little overlap with each other or with the 262 probeset classifier, indicating that the three tests are measuring different aspects of islet cell biology. A subset of 36 probesets surpassed the predictive accuracy of the entire set for reversal of diabetes, and was further reduced by logistic regression to sets of 14 and 5 without losing accuracy. These genes were further validated with an independent cohort of 16 samples. We believe this limited number of gene classifiers in combination with other tests may provide complementary verification of islet quality prior to their clinical use.

Elevation of circulating TNF receptors 1 and 2 increases the risk of end-stage renal disease in American Indians with type 2 diabetes

In Caucasians with type 2 diabetes, circulating TNF receptors 1 (TNFR1) and 2 (TNFR2) predict end-stage renal disease (ESRD). Here we examined this relationship in a longitudinal cohort study of American Indians with type 2 diabetes with measured glomerular filtration rate (mGFR, iothalamate) and urinary albumin-to-creatinine ratio (ACR). ESRD was defined as dialysis, kidney transplant, or death attributed to diabetic kidney disease. Age-gender-adjusted incidence rates and incidence rate ratios of ESRD were computed by Mantel-Haenszel stratification. The hazard ratio of ESRD was assessed per interquartile range increase in the distribution of each TNFR after adjusting for baseline age, gender, mean blood pressure, HbA1c, ACR, and mGFR. Among the 193 participants, 62 developed ESRD and 25 died without ESRD during a median follow-up of 9.5 years. The age-gender-adjusted incidence rate ratio of ESRD was higher among participants in the highest versus lowest quartile for TNFR1 (6.6, 95% confidence interval (CI) 3.3-13.3) or TNFR2 (8.8, 95% CI 4.3-18.0). In the fully adjusted model, the risk of ESRD per interquartile range increase was 1.6 times (95% CI 1.1-2.2) as high for TNFR1 and 1.7 times (95% CI 1.2-2.3) as high for TNFR2. Thus, elevated serum concentrations of TNFR1 or TNFR2 are associated with increased risk of ESRD in American Indians with type 2 diabetes after accounting for traditional risk factors including ACR and mGFR.

On the TRAIL of obesity and diabetes

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) has been extensively studied for its preferential ability to induce apoptosis of cancer cells. Beyond the cytotoxic capacity of TRAIL, new physiological and pathological roles for TRAIL have been identified, and there is now growing evidence supporting its involvement in the development of obesity and diabetes. This review summarizes the most recent findings associating TRAIL with obesity and diabetes in both humans and experimental settings. We also present and discuss some of the reported controversies behind TRAIL signaling and function. Understanding TRAIL mechanism(s) in vivo and its involvement in disease may lead to novel strategies to combat the growing pandemic of obesity and diabetes worldwide.

Trail overexpression inversely correlates with histological differentiation in intestinal-type sinonasal adenocarcinoma

Introduction. Despite their histological resemblance to colorectal adenocarcinoma, there is some information about the molecular events involved in the pathogenesis of intestinal-type sinonasal adenocarcinomas (ITACs). To evaluate the possible role of TNF-related apoptosis-inducing ligand (TRAIL) gene defects in ITAC, by investigating the immunohistochemical expression of TRAIL gene product in a group of ethmoidal ITACs associated with occupational exposure. Material and Methods. Retrospective study on 23 patients with pathological diagnosis of primary ethmoidal ITAC. Representative formalin-fixed, paraffin-embedded block from each case was selected for immunohistochemical studies using the antibody against TRAIL. Clinicopathological data were also correlated with the staining results. Results. The immunohistochemical examination demonstrated that poorly differentiated cases showed a higher percentage of TRAIL expressing cells compared to well-differentiated cases. No correlation was found with other clinicopathological parameters, including T, stage and relapses. Conclusion. The relationship between upregulation of TRAIL and poorly differentiated ethmoidal adenocarcinomas suggests that the mutation of this gene, in combination with additional genetic events, could play a role in the pathogenesis of ITAC.

Association of circulating sTRAIL and high-sensitivity CRP with type 2 diabetic nephropathy and foot ulcers

BACKGROUND

Hyperglycemia is among the potent factors that may induce or facilitate apoptosis. TNF-Related Apoptosis-Inducing Factor (TRAIL) is known for its apoptotic and immunomodulatory effects that have recently been correlated with diabetes. We examined serum-soluble TRAIL (sTRAIL) and high-sensitivity CRP (hs-CRP) levels and their association with various distinct parameters in type 2 diabetic nephropathy patients with diabetic foot disease.

MATERIAL/METHODS

Twenty-two diabetic nephropathy patients with foot ulcers were enrolled in our study. Patients had been diagnosed with diabetes at age 24±10.58 years. Circulating sTRAIL and Hs-CRP levels were compared with control values, and possible correlations were investigated with parameters such as age, Wagner's Grade (WG), BMI, HbA1c, and creatinine.

RESULTS

Serum sTRAIL levels were significantly reduced in the patient group, compared to healthy subjects. High HsCRP levels correlated with age, and WGS correlated with BMI and creatinine levels.

CONCLUSIONS

Significantly suppressed sTRAIL levels in diabetic nephropathy patients with foot ulcers compared to healthy controls suggest a protective role for TRAIL in the disease setting.

Imaging of β-cell mass and insulitis in insulin-dependent (Type 1) diabetes mellitus

Insulin-dependent (type 1) diabetes mellitus is a metabolic disease with a complex multifactorial etiology and a poorly understood pathogenesis. Genetic and environmental factors cause an autoimmune reaction against pancreatic β-cells, called insulitis, confirmed in pancreatic samples obtained at autopsy. The possibility to noninvasively quantify β-cell mass in vivo would provide important biological insights and facilitate aspects of diagnosis and therapy, including follow-up of islet cell transplantation. Moreover, the availability of a noninvasive tool to quantify the extent and severity of pancreatic insulitis could be useful for understanding the natural history of human insulin-dependent (type 1) diabetes mellitus, to early diagnose children at risk to develop overt diabetes, and to select patients to be treated with immunotherapies aimed at blocking the insulitis and monitoring the efficacy of these therapies. In this review, we outline the imaging techniques currently available for in vivo, noninvasive detection of β-cell mass and insulitis. These imaging techniques include magnetic resonance imaging, ultrasound, computed tomography, bioluminescence and fluorescence imaging, and the nuclear medicine techniques positron emission tomography and single-photon emission computed tomography. Several approaches and radiopharmaceuticals for imaging β-cells and lymphocytic insulitis are reviewed in detail.

TRAIL and DcR1 expressions are differentially regulated in the pancreatic islets of STZ- versus CY-applied NOD mice

TNF-related apoptosis-inducing ligand (TRAIL) is an important component of the immune system. Although it is well acknowledged that it also has an important role in Type 1 Diabetes (T1D) development, this presumed role has not yet been clearly revealed. Streptozotocin (STZ) and Cyclophosphamide (CY) are frequently used agents for establishment or acceleration of T1D disease in experimental models, including the non-obese diabetic (NOD) mice. Although such disease models are very suitable for diabetes research, different expression patterns for various T1D-related molecules may be expected, depending on the action mechanism of the applied agent. We accelerated diabetes in female NOD mice using STZ or CY and analyzed the expression profiles of TRAIL ligand and receptors throughout disease development. TRAIL ligand expression followed a completely different pattern in STZ- versus CY-accelerated disease, displaying a prominent increase in the former, while appearing at reduced levels in the latter. Decoy receptor 1 (DcR1) expression also increased significantly in the pancreatic islets in STZ-induced disease. Specific increases observed in TRAIL ligand and DcR1 expressions may be part of a defensive strategy of the beta islets against the infiltrating leukocytes, while the immune-suppressive agent CY may partly hold down this defense, contributing further to diabetes development.

Clinical significance of TRAIL and TRAIL receptors in patients with head and neck cancer

BACKGROUND

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a death ligand currently under clinical trials for cancer. The molecular profile of TRAIL and TRAIL receptors has not yet been mapped for patients with laryngeal squamous cell carcinoma (SCC) or patients with oral cavity squamous cell carcinoma (OCSCC).

METHODS

Paraffin-embedded tissues from 60 patients with laryngeal SCC and 14 patients with OCSCC were retrospectively analyzed using immunohistochemistry.

RESULTS

An increase in decoy-R1 (DcR1) but a decrease in decoy-R2 (DcR2) expression were observed in patients with laryngeal SCC and in patients with OCSCC compared with control individuals with benign lesions. Clinical and pathologic grading revealed distinctive TRAIL and TRAIL receptor profiles in patients with squamous cell carcinoma of the head and neck (SCCHN).

CONCLUSIONS

TRAIL and a TRAIL receptor expression profile might be useful to follow-up disease progression by virtue of its connection with clinical staging and pathologic grading in patients with laryngeal SCC.

High TRAIL death receptor 4 and decoy receptor 2 expression correlates with significant cell death in pancreatic ductal adenocarcinoma patients

OBJECTIVES

The importance of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and TRAIL receptor expression in pancreatic carcinoma development is not known. To reveal the putative connection of TRAIL and TRAIL receptor expression profile to this process, we analyzed and compared the expression profile of TRAIL and its receptors in pancreatic tissues of both noncancer patients and patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

Thirty-one noncancer patients and 34 PDAC patients were included in the study. TRAIL and TRAIL receptor expression profiles were determined by immunohistochemistry. Annexin V binding revealed the apoptotic index in pancreas. Lastly, the tumor grade, tumor stage, tumor diameter, perineural invasion, and number of lymph node metastasis were used for comparison purposes.

RESULTS

TRAIL decoy receptor 2 (DcR2) and death receptor 4 expression were up-regulated in PDAC patients compared with noncancer patients, and the ductal cells of PDAC patients displayed significant levels of apoptosis. In addition, acinar cells from PDAC patients had higher DcR2 expression but lower death receptor 4 expression. Increased DcR2 expression was also observed in Langerhans islets of PDAC patients.

CONCLUSIONS

Differential alteration of TRAIL and TRAIL receptor expression profiles in PDAC patients suggest that the TRAIL/TRAIL receptor system may play a pivotal role during pancreatic carcinoma development.

Molecular mechanisms of death ligand-mediated immune modulation: a gene therapy model to prolong islet survival in type 1 diabetes

Type 1 diabetes results from the T cell-mediated destruction of pancreatic beta cells. Islet transplantation has recently become a potential therapeutic approach for patients with type 1 diabetes. However, islet-graft failure appears to be a challenging issue to overcome. Thus, complementary gene therapy strategies are needed to improve the islet-graft survival following transplantation. Immune modulation through gene therapy represents a novel way of attacking cytotoxic T cells targeting pancreatic islets. Various death ligands of the TNF family such as FasL, TNF, and TNF-Related Apoptosis-Inducing Ligand (TRAIL) have been studied for this purpose. The over-expression of TNF or FasL in pancreatic islets exacerbates the onset of type 1 diabetes generating lymphocyte infiltrates responsible for the inflammation. Conversely, the lack of TRAIL expression results in higher degree of islet inflammation in the pancreas. In addition, blocking of TRAIL function using soluble TRAIL receptors facilitates the onset of diabetes. These results suggested that contrary to what was observed with TNF or FasL, adenovirus mediated TRAIL gene delivery into pancreatic islets is expected to be therapeutically beneficial in the setting of experimental models of type 1 diabetes. In conclusion; this study mainly reveals the fundamental principles of death ligand-mediated immune evasion in diabetes mellitus.

High levels of endogenous tumor necrosis factor-related apoptosis-inducing ligand expression correlate with increased cell death in human pancreas

OBJECTIVES

Type 1 diabetes (T1D) has been characterized by the T cell-mediated destruction of pancreatic beta cells. Although various members of the tumor necrosis factor (TNF) family, such as Fas ligand or TNF, have recently been implicated in the development of T1D, the lack of TNF-related apoptosis-inducing ligand (TRAIL) expression or function facilitates the onset of T1D. Thus, the goal of the present study was to investigate the expression profiles of TRAIL and its receptors in human pancreas.

METHODS

Pancreata of 31 patients were analyzed by immunohistochemistry using antibodies developed against TRAIL and its receptors. Apoptosis was confirmed by Annexin V-fluorescein isothiocyanate binding and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling assays.

RESULTS

Acinar cells displayed high levels of TRAIL and death receptor 4, but only low levels of death receptor 5. In contrast, only TRAIL and TRAIL decoy receptors (DcR1, DcR2) were detected in ductal cells. Similarly, Langerhans islets expressed only TRAIL and TRAIL decoy receptor. High levels of TRAIL expression in pancreas correlated with increased number of apoptotic cells.

CONCLUSIONS

Although the expression of TRAIL decoy receptors might be necessary for defense from TRAIL-induced apoptosis, high levels of TRAIL may provide protection for Langerhans islets from the immunological attack of cytotoxic T cells.

Effect of gliclazide modified release on adiponectin, interleukin-6, and tumor necrosis factor-alpha plasma levels in individuals with type 2 diabetes mellitus

OBJECTIVE

The aim of the study was to evaluate the effect of gliclazide modified release (MR) treatment on adiponectin, interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) plasma concentrations in type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

24 randomly selected type 2 diabetic patients, aged 61.2 +/- 15.4 years, with poorly controlled glucose level (mean glycated hemoglobin [HbA1c] 7.6 +/- 1.1%) despite treatment with diet and/or oral hypoglycemic agents, were included in the study. All of the patients, after a 2-week run-in period, were given gliclazide MR for 12 weeks. At baseline, and after gliclazide MR treatment, HbA(1c) and plasma concentrations of IL-6, TNF-alpha, and adiponectin were measured.

RESULTS

Gliclazide MR treatment produced significant reductions in fasting plasma glucose (from 7.6 +/- 1.4 to 6.6 +/- 1.2 mmol/L, p < 0.01), HbA(1c) (from 7.6 +/- 1.1 to 6.9 +/- 0.8%, p < 0.01), and plasma IL-6 concentrations (from 2.5 +/- 1.8 to 1.8 +/- 1.2 pg/mL, p < 0.05). A significant increase in plasma adiponectin level was noted (from 6.4 +/- 3.3 to 7.6 +/- 4.4 mug/mL, p < 0.05). Plasma TNF-alpha concentrations and homeostasis model assessment of insulin resistance (HOMA-IR) decreased after treatment, but these changes did not reach statistical significance.

CONCLUSIONS

Gliclazide MR improves glycemic control and, in addition, has a positive influence on the plasma level of some inflammatory markers and adiponectin. Increased plasma adiponectin and decreased plasma IL-6, and TNF-alpha levels may explain, at least in part, the anti-atherogenic action of this drug reported elsewhere.

Apoptosis in autoimmune diabetes: the fate of beta-cells in the cleft between life and death

Cytokine-induced beta-cell death is the end-stage event in the pathogenesis of autoimmune diabetes. Beside cytokines, several pro-apoptotic pathways mediated through nitric oxide, reactive oxygen species, glucose and Fas ligation can be involved, suggesting that programmed cell death (PCD) is a critical aspect in this process. The apoptotic program is activated by the utilization of the Fas/Fas-ligand (FasL) axis in the interrelation of T and beta-cells. Evidence for this mechanism arose from the finding that beta-cells in NOD mice could be protected from apoptosis by blocking the Fas-FasL pathway. Glucose is a regulator of Fas expression on human beta-cells and elevated glucose levels may contribute to accelerated beta-cell destruction by constitutively expressed FasL independently of the autoimmune reaction. It can thus be concluded that immunological, as well as metabolic, pathways may act in concert to cause beta-cell destruction. Much experimental work has been carried out to manipulate beta-cells in transgenic mice expressing apoptosis modulators in islets. For example, the transcription factor, nuclear factor-kappaB (NF-kappaB), promotes the expression of several beta-cell genes, including pro- and anti-apoptotic genes. The prevention of cytokine-induced gene expression of several NF-kappaB targets, such as inducible nitric oxide synthase, Fas, and manganese superoxide dismutase can prevent beta-cell death. Thus, modulating the expression of apoptotic mediators may significantly affect the end-stage outcome of autoimmune diabetes and could thus be a potential avenue for clinical therapy, even though currently existing findings remain exploratory due to the restrictions of transgenic mouse models.

Regulation of TNF-Related Apoptosis-Inducing Ligand-Mediated Death-Signal Pathway in Human β Cells by Fas-Associated Death Domain and Nuclear Factor κB

Transfectants of human CM and NES2Y beta cell lines and primary islets transfected by FADD-DN (dominant-negative form of Fas-associated death domain), a mutant of FADD and/or a superrepressor of nuclear factor kappaB (NF-kappaB) (AdIkappaB(SA)2), were examined for their susceptibility to the TRAIL (TNF-related apoptosis-inducing ligand)-induced death signal pathway, compared with controls, wild-type cells, and vector transfectants in caspase fluorescence, Western blot, electrophoretic mobility shift, apoptosis, and cytotoxicity assays. FADD-DN inhibited caspase-8 activation induced by TRAIL in the transfectants of CM and NES2Y cells. TRAIL-induced apoptosis and cytotoxicity to the FADD-DN transfectants were decreased in comparison to those responses in controls (CM, p < 0.01 and p < 0.01; NES2Y, p < 0.05, and p < 0.02, respectively). When CM, NES2Y, and primary islet cells were transfected by AdIkappaB(SA)2, TRAIL-induced IkappaB degradation and nuclear translocation of NF-kappaB p50/p65 were blocked. TRAIL-induced apoptosis and cytotoxicity to AdIkappaB(SA)2 transfectants of these cells were also reduced (CM, p < 0.02 and p < 0.02; NES2Y, p < 0.01 and p < 0.01, respectively, and islet p < 0.01 for cytotoxicity). Finally, cytotoxicity induced by TRAIL in CM and NES2Y cells transfected with both FADD-DN and AdIkappaB(SA)2 was reduced, compared with that observed in these cells transfected with either FADD-DN alone or AdIkappaB(SA)2 alone, suggesting that FADD and NF-kappaB have synergistic proapoptotic regulatory effects on the susceptibility of beta cell lines and islet cells to TRAIL-induced destruction.

Synergistic inhibition of tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis in human pancreatic β cells by Bcl-2 and X-linked inhibitor of apoptosis

To better understand the cytokine death-signal transduction pathways in human beta cells, we investigated the inhibitory effects of Bcl-2 (protooncogene bcl-2) and X-linked inhibitor of apoptosis (XIAP) on TRAIL (TNF-related apoptosis-inducing ligand)-induced human beta-cell destruction. A panel of Bcl-2-overexpressing transfectants of the human beta-cell lines NES2Y and CM was developed by transfection with a pEFpGKpuro vector containing Bcl-2 or an empty vector as a control. TRAIL-induced cytotoxicity and apoptosis of Bcl-2-overexpressing beta cells were clearly decreased, in comparison with wild-type cells and the empty vector transfectants. XIAP-overexpressing CM, NES2Y, and primary islet cells were generated by exposing cells to recombinant adenovirus-expressing XIAP (AdXIAP) or AdLacz as a control. TRAIL-induced cytotoxicity and apoptosis of CM, NES2Y, and primary islet cells infected with AdXIAP were clearly reduced compared with controls. Interestingly, cytotoxicity induced by TRAIL in human beta cells transfected with both Bcl-2 and AdXIAP was much less than that observed in human beta cells transfected with either Bcl-2 or XIAP alone (p < 0.005 in CM and p < 0.03 in NES2Y). Overexpression of both Bcl-2 and XIAP inhibited TRAIL-induced activation of caspases as well as TRAIL-mediated damage of mitochondrial function in cells, suggesting possible regulatory mechanisms. These results indicate that Bcl-2 and XIAP synergistically inhibit TRAIL-mediated death pathways in human beta cells.