The beneficial pleiotropic effects of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) within the vasculature: A review of the evidence

Circulating cytokines and vascular dementia: A bi-directional Mendelian randomization study

Inflammatory responses are associated with the development of vascular dementia (VaD). Circulating cytokines modulate the inflammatory response and are important for the immune system. To further elucidate the role of the immune system in VaD, we used Mendelian randomization (MR) to comprehensively and bi-directionally assess the role of circulating cytokines in VaD. Using state-of-the-art genome-wide association studies, we primarily assessed whether different genetic levels of 41 circulating cytokines affect the risk of developing VaD and, in turn, whether the genetic risk of VaD affects these circulating cytokines. We used inverse variance weighting (IVW) and several other MR methods to assess the bidirectional causality between circulating cytokines and VaD, and performed sensitivity analyses. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was inversely associated with VaD risk [odds ratio (OR): 0.74, 95 % confidence interval (CI): 0.60-0.92, P = 0.007, 0.007]. VaD was associated with seven circulating cytokines: macrophage inflammatory protein 1b (MIP-1 beta) [OR: 1.05, 95 % CI: 1.01-1.08, P = 0.009], Interleukin-12p70 (IL-12) [OR: 1.04, 95 % CI: 1.00-1.08, P = 0.047], Interleukin-17 (IL-17) [OR: 1.04, 95 % CI: 1.00-1.07, P = 0.038], Interleukin-7 (IL-7) [OR: 1.07, 95 % CI: 1.02-1.12, P = 0.009], Interferon gamma (IFN-γ) [OR: 1.03, 95 % CI: 1.00-1.07, P = 0.046], Granulocyte-colony stimulating factor (GCSF) [OR: 1.06, 95 % CI: 1.02-1.09, P = 0.001], Fibroblast growth factor (FGF) [P = 0.001], and Fibroblast growth factor (FGF) [P = 0.001]. Fibroblast growth factor basic (FGF-Basic) [OR: 1.04, 95 % CI: 1.01-1.08, P = 0.02] were positively correlated. Circulating cytokines are associated with VaD, and further studies are needed to determine whether they are effective targets for intervention to prevent or treat VaD.

Causal relationship between inflammatory factors and cerebral small vessel disease: Univariate, multivariate, and summary-data-based mendelian randomization analysis

OBJECTIVE

To explore the impact of inflammatory factors on the incidence of cerebral small vessel disease (CSVD), we performed a mendelian randomization (MR) study to analyze the causal relationship between multiple inflammatory factors and CSVD imaging markers and utilized summary-data-based mendelian randomization (SMR) analysis to infer whether the impact of instrumental variables (IVs) on disease is mediated by gene expression or DNA methylation.

METHODS

Using public databases such as UKB and IEU, and original genome-wide association studies, we obtained IVs related to exposure (inflammatory factors) and outcome (CSVD imaging markers). We performed the inverse variance weighted, weighted median, and MR-Egger methods to assess causal effects between exposure and outcome in univariate MR analysis. To evaluate their heterogeneity, a series of sensitivity analyses were conducted, including the Cochrane Q test, MR-Egger intercept test, MR-Presso, and leave-one-out analysis. We also applied mediation and multivariate MR analysis to explore the interactions between positive exposures on the same outcome. Additionally, we conducted the SMR, which utilizes instruments within or near relevant genes in blood or brain tissues, to elucidate the causal associations with CSVD markers.

RESULTS

ABO Univariate MR of multiple cohorts revealed that the risk of small vessel stroke (SVS) increases with elevated levels of TNF-related apoptosis-inducing ligand (TRAIL, OR, 1.23, 95% CI, 1.08-1.39) and interleukin-1 receptor-like 2, (IL-1RL2, OR, 1.29, 95% CI, 1.04-1.61). IL-18 was a potential risk factor for extensive basal ganglia perivascular space burden (BGPVS, OR, 1.02, 95% CI, 1.00-1.05). Moreover, the risk of extensive white matter perivascular space burden (WMPVS) decreased with rising levels of E-selectin (OR, .98, 95% CI, .97-1.00), IL-1RL2 (OR, .97, 95% CI, .95-1.00), IL-3 receptor subunit alpha (IL-3Ra, OR, .98, 95% CI, .97-1.00), and IL-5 receptor subunit alpha (IL-5Ra, OR, .98, 95% CI, .97-1.00). Mediation and multivariate MR analysis indicated that E-selectin and IL-3Ra might interact during the pathogenesis of WMPVS. SMR estimates showed that TRAIL-related IVs rs5030044 and rs2304456 increased the risk of SVS by increasing the expression of gene Kininogen-1 (KNG1) in the cerebral cortex, particularly in the frontal cortex (βsmr = .10, Psmr = .003, FDR = .04). Instruments (rs507666 and rs2519093) related to E-selectin and IL-3Ra could increase the risk of WMPVS by enhancing DNA methylation of the gene ABO in blood tissue (βsmr = .01-.02, Psmr = .001, FDR = .01-.03).

CONCLUSION

According to MR and SMR analysis, higher levels of TRAIL increased the risk of SVS by upregulating gene expression of KNG1 in brain cortex tissues. In addition, protective effects of E-selectin and IL-3a levels on WMPVS were regulated by increased DNA methylation of gene ABO in blood tissue.

Breast tumors interfere with endothelial TRAIL at the premetastatic niche to promote cancer cell seeding

Endothelial cells (ECs) grant access of disseminated cancer cells to distant organs. However, the molecular players regulating the activation of quiescent ECs at the premetastatic niche (PMN) remain elusive. Here, we find that ECs at the PMN coexpress tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its cognate death receptor 5 (DR5). Unexpectedly, endothelial TRAIL interacts intracellularly with DR5 to prevent its signaling and preserve a quiescent vascular phenotype. In absence of endothelial TRAIL, DR5 activation induces EC death and nuclear factor κB/p38-dependent EC stickiness, compromising vascular integrity and promoting myeloid cell infiltration, breast cancer cell adhesion, and metastasis. Consistently, both down-regulation of endothelial TRAIL at the PMN by proangiogenic tumor-secreted factors and the presence of the endogenous TRAIL inhibitors decoy receptor 1 (DcR1) and DcR2 favor metastasis. This study discloses an intracrine mechanism whereby TRAIL blocks DR5 signaling in quiescent endothelia, acting as gatekeeper of the vascular barrier that is corrupted by the tumor during cancer cell dissemination.

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.

Serum OPG and RANKL Levels as Risk Factors for the Development of Cardiovascular Calcifications in End-Stage Renal Disease Patients in Hemodialysis

Cardiovascular calcifications (CVC) are frequently observed in chronic kidney disease (CKD) patients and contribute to their cardiovascular mortality. The aim of the present study was to investigate the impact of osteoprotegerin (OPG)/Receptor Activator of NF-κΒ (RANK)/RANK ligand (RANKL) pathway in the development and evolution of CVCs in hemodialysis patients. In total, 80 hemodialysis patients were assessed for the presence of vascular (abdominal aorta and muscular arteries) calcifications and results were correlated to serum OPG and RANKL levels and the OPG/RANKL ratio. Traditional cardiovascular risk factors and mineral bone disease parameters were also estimated. The presence of VCs was also evaluated 5 years after the initiation of the study, and results were correlated to the initial serum OPG levels. Age, diabetes mellitus, coronary artery disease and OPG levels (p < 0.001) were associated with VCs, whereas RANKL levels were not. Multivariate analysis though revealed that only OPG levels were significantly associated with abdominal aorta calcifications (p = 0.026), but they were not correlated with the progression of VCs. Serum OPG levels are positively and independently associated with VCs in HD patients, but not with their progression. RANKL levels did not show any associations, whereas further studies are needed to establish the significance of OPG/RANKL ratio.

Inflammatory biomarkers after an exercise intervention in childhood acute lymphoblastic leukemia survivors

Cancer survivors show increased risk for non-communicable diseases and chronic low-grade inflammation characterizes the development of such diseases. We investigated inflammatory plasma protein profiles of survivors of childhood acute lymphoblastic leukemia (ALL) in comparison to healthy controls and after an intervention with a home-based exercise program. Survivors of childhood ALL aged 16-30 years (n = 21) with a median age at diagnosis 4.9 (1.6-12.9) years and a median time of 15.9 years from diagnosis, and sex- and age-matched healthy controls (n = 21) were studied. Stored plasma samples were analyzed with Olink's 92-protein-wide Inflammation panel in 21 ALL long-term survivors at baseline, after a previous 16-week home-based exercise intervention (n = 17) and in 21 age- and sex-matched controls at baseline. Protein expression levels were compared between the groups. Inflammatory protein levels did not differ between the survivors and controls at baseline. Significantly reduced levels after the intervention were found in 11 proteins related to either vascular inflammation, insulin resistance, or both: tumor necrosis factor superfamily member 14 (TNFSF14), oncostatin M (OSM), monocyte chemoattractant protein 1 (MCP-1), MCP-2, fibroblast growth factor 21 (FGF-21), chemokine (C-C motif) ligand 4 (CCL4), transforming growth factor alpha (TGF-α), tumor necrosis factor-related apoptosis-inducing ligand 10 (TRAIL), adenosine deaminase (ADA), chemokine (C-X-C motif) ligand 6 (CXCL6), and latency-associated peptide transforming growth factor beta 1 (LAP TGF-β1). The ALL survivors were not significantly more affected by inflammation than controls at baseline. The survivors' 16-week exercise intervention led to significant reduction in inflammatory protein levels. Physical exercise should be promoted for survivors of childhood cancer.

Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL): A Novel Biomarker for Prognostic Assessment and Risk Stratification of Acute Pulmonary Embolism

Background: Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is associated with poor prognosis in cardiovascular diseases. However, the predictive value of TRAIL for the short-term outcome and risk stratification of acute pulmonary embolism (PE) remains unknown. Methods: This study prospectively included 151 normotensive patients with acute PE. The study outcome was a composite of 30-day adverse events, defined as PE-related death, shock, mechanical ventilation, cardiopulmonary resuscitation, and major bleeding. Results: Overall, nine of 151 (6.0%) patients experienced 30-day adverse composite events. Multivariable logistic regression showed that TRAIL was an independent predictor of study outcome (OR 0.19 per SD; 95% CI 0.04–0.90). An ROC curve revealed that TRAIL’s area under the curve (AUC) was 0.83 (95% CI 0.76–0.88). The optimal cut-off value for TRAIL was 18 pg/mL, with a sensitivity, specificity, negative predictive value, positive predictive value, positive likelihood ratio, and negative likelihood ratio of 89%, 69%, 99%, 15%, 2.87, and 0.16, respectively. Compared with the risk stratification algorithm outlined in the 2019 ESC guidelines, our biomarker-based risk stratification strategy (combining TRAIL and hs-cTnI) has a similar risk classification effect. Conclusion: Reduced plasma TRAIL levels predict short-term adverse events in normotensive patients with acute PE. The combination of the 2019 ESC algorithm and TRAIL aids risk stratification in normotensive patients with acute PE.

Increased risk of adverse cardiovascular events by strict glycemic control after percutaneous coronary intervention (HbA1c < 6.5% at 2 years) in type 2 diabetes mellitus combined with acute coronary syndrome: a 5-years follow-up study

OBJECTIVE

This study assessed the association between HbA1c level measured 2 years after percutaneous coronary intervention (PCI) and long-term clinical outcomes in type 2 diabetes mellitus combined with acute coronary syndrome (ACS) who underwent PCI.

METHODS

This prospective observational study analyzed 2877 ACS patients with type 2 diabetes mellitus whose baseline HbA1c ≥ 7.0% and underwent PCI. All patients were divided into 6 groups according to the HbA1c level at 2 years after PCI. The clinical outcome was major adverse cardiovascular events (MACEs), defined as all-cause death, all myocardial infarction, any revascularization, congestive heart failure, ischemic stroke. The median follow-up duration was 4.1 years.

RESULTS

All 2877 patients were divided into 6 groups: 2-year after PCI HbA1c < 6.0% (n = 219), 6.0-6.5% (n = 348), 6.5-7.0% (n = 882), 7.0-7.5% (n = 567), 7.5-8.0% (n = 441), ≥8.0% (n = 420). The 5-year incidence rate of MACEs in HbA1c <6.0% and 6.0-6.5% groups were similar to 7.5-8.0% and ≥8.0% groups, which were significantly higher than in 6.5-7.0% and 7.0-7.5% groups (p = .044). The cumulative incidence rate of MACEs significantly differed among the groups (p = .046). Multivariate Cox regression analysis revealed a U-shaped relationship between 2-year HbA1c level after PCI and risk of MACEs. 2-year HbA1c <6.5% after PCI was an independent risk factor for MACEs in type 2 diabetes mellitus combined with ACS who underwent PCI (p < .001).

CONCLUSIONS

The findings indicated an increased risk of MACEs by strict glycemic control after PCI (2-year HbA1c < 6.5% after PCI) in type 2 diabetes mellitus combined with ACS who underwent PCI.

Harnessing TRAIL-Induced Apoptosis Pathway for Cancer Immunotherapy and Associated Challenges

The immune cytokine tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has attracted rapidly evolving attention as a cancer treatment modality because of its competence to selectively eliminate tumor cells without instigating toxicity in vivo. TRAIL has revealed encouraging promise in preclinical reports in animal models as a cancer treatment option; however, the foremost constraint of the TRAIL therapy is the advancement of TRAIL resistance through a myriad of mechanisms in tumor cells. Investigations have documented that improvement of the expression of anti-apoptotic proteins and survival or proliferation involved signaling pathways concurrently suppressing the expression of pro-apoptotic proteins along with down-regulation of expression of TRAILR1 and TRAILR2, also known as death receptor 4 and 5 (DR4/5) are reliable for tumor cells resistance to TRAIL. Therefore, it seems that the development of a therapeutic approach for overcoming TRAIL resistance is of paramount importance. Studies currently have shown that combined treatment with anti-tumor agents, ranging from synthetic agents to natural products, and TRAIL could result in induction of apoptosis in TRAIL-resistant cells. Also, human mesenchymal stem/stromal cells (MSCs) engineered to generate and deliver TRAIL can provide both targeted and continued delivery of this apoptosis-inducing cytokine. Similarly, nanoparticle (NPs)-based TRAIL delivery offers novel platforms to defeat barricades to TRAIL therapeutic delivery. In the current review, we will focus on underlying mechanisms contributed to inducing resistance to TRAIL in tumor cells, and also discuss recent findings concerning the therapeutic efficacy of combined treatment of TRAIL with other antitumor compounds, and also TRAIL-delivery using human MSCs and NPs to overcome tumor cells resistance to TRAIL.

Osteoprotegerin predicts cardiovascular events in patients treated with hemodialysis

BACKGROUND

Disturbances in bone mineral metabolism are associated with increased mortality and cardiovascular events (CVEs). However, the association between bone-associated protein biomarkers, mortality, and CVEs independent of cytokine activation remains unknown. This study aimed to investigate bone-associated protein biomarkers, and the association with inflammatory cytokines, and cardiovascular outcomes.

METHODS

This prospective study enrolled hemodialysis (HD) patients in Denmark between December 2010 and March 2011. Using a proximity extension proteomics assay, nine bone-associated proteins were examined: cathepsin D (CTSD), cathepsin L1 (CTSL1), dickkopf-related protein 1 (Dkk-1), fibroblast growth factor 23 (FGF-23), leptin, osteoprotegerin (OPG), receptor activator of nuclear factor kappa-Β ligand (RANKL), TNF-related apoptosis-inducing ligand (TRAIL), and TNF-related apoptosis-inducing ligand receptor 2 (TRAIL-R2). The importance of the bone-associated protein markers was evaluated by a random forest algorithm (RF). The association between bone-associated proteins with all-cause death, cardiovascular death, and CVEs was analyzed in multivariable Cox models adjusted for age, gender, comorbidities, laboratory data, and dialysis duration.

RESULTS

We enrolled 331 patients (63.7% men; mean [SD] age, 65 [14.6] years) in a prospective cohort study with five years follow-up. When adjusting for confounders, CTSL1 remained associated with all-cause death, and four biomarkers were associated with CVE. However, the association between bone markers and the outcomes was attenuated after adjusting for inflammatory proteins, and just OPG remained associated with CVE in the adjusted model. Evaluating the importance of bone markers by RF, OPG was the most important marker related to CVEs. OPG also improved the prediction of CVE when added clinical information alone in integrated discrimination improvement and net reclassification improvement analyses.

DISCUSSION

OPG, a well-known bone biomarker, was associated with CVEs independent of cytokine activity. In contrast, the association between CVEs and the remaining three bone-associated proteins (TRAIL-R2, CTSD, and CTSL1) was affected by cytokine inflammation activity.

Apoptosis in the Extraosseous Calcification Process

Extraosseous calcification is a pathologic mineralization process occurring in soft connective tissues (e.g., skin, vessels, tendons, and cartilage). It can take place on a genetic basis or as a consequence of acquired chronic diseases. In this last case, the etiology is multifactorial, including both extra- and intracellular mechanisms, such as the formation of membrane vesicles (e.g., matrix vesicles and apoptotic bodies), mitochondrial alterations, and oxidative stress. This review is an overview of extraosseous calcification mechanisms focusing on the relationships between apoptosis and mineralization in cartilage and vascular tissues, as these are the two tissues mostly affected by a number of age-related diseases having a progressively increased impact in Western Countries.

A TRAIL-TL1A Paracrine Network Involving Adipocytes, Macrophages, and Lymphocytes Induces Adipose Tissue Dysfunction Downstream of E2F1 in Human Obesity

Elevated expression of E2F1 in adipocyte fraction of human visceral adipose tissue (hVAT) associates with a poor cardiometabolic profile. We hypothesized that beyond directly activating autophagy and MAP3K5 (ASK)-MAP kinase signaling, E2F1 governs a distinct transcriptome that contributes to adipose tissue and metabolic dysfunction in obesity. We performed RNA sequencing of hVAT samples from age-, sex-, and BMI-matched patients, all obese, whose visceral E2F1 protein expression was either high (E2F1^high) or low (E2F1^low). Tumor necrosis factor superfamily (TNFSF) members, including TRAIL (TNFSF10), TL1A (TNFSF15), and their receptors, were enriched in E2F1^high While TRAIL was equally expressed in adipocytes and stromal vascular fraction (SVF), TL1A was mainly expressed in SVF, and TRAIL-induced TL1A was attributed to CD4⁺ and CD8⁺ subclasses of hVAT T cells. In human adipocytes, TL1A enhanced basal and impaired insulin-inhibitable lipolysis and altered adipokine secretion, and in human macrophages it induced foam cell biogenesis and M1 polarization. Two independent human cohorts confirmed associations between TL1A and TRAIL expression in hVAT and higher leptin and IL6 serum concentrations, diabetes status, and hVAT-macrophage lipid content. Jointly, we propose an intra-adipose tissue E2F1-associated TNFSF paracrine loop engaging lymphocytes, macrophages, and adipocytes, ultimately contributing to adipose tissue dysfunction in obesity.

Insight into the divergent role of TRAIL in non-neoplastic neurological diseases

Tumour necrosis factor–related apoptosis‐inducing ligand (TRAIL) is a member of the tumour necrosis factor (TNF) superfamily which mainly induces apoptosis of tumour cells and transformed cell lines with no systemic toxicity, whereas they share high sequence homology with TNF and CD95L. These unique effects of TRAIL have made it an important molecule in oncology research. However, the research on TRAIL‐related antineoplastic agents has lagged behind and has been limited by the extensive drug resistance in cancer cells. Given the several findings showing that TRAIL is involved in immune regulation and other pleiotropic biological effects in non‐malignant cells, TRAIL and its receptors have attracted widespread attention from researchers. In the central nervous system (CNS), TRAIL is highly correlated with malignant tumours such as glioma and other non‐neoplastic disorders such as acute brain injury, CNS infection and neurodegenerative disease. Many clinical and animal studies have revealed the dual roles of TRAIL in which it causes damage by inducing cell apoptosis, and confers protection by enhancing both pro‐ and non‐apoptosis effects in different neurological disorders and at different sites or stages. Its pro‐apoptotic effect produces a pro‐survival effect that cannot be underestimated. This review extensively covers in vitro and in vivo experiments and clinical studies investigating TRAIL. It also provides a summary of the current knowledge on the TRAIL signalling pathway and its involvement in pathogenesis, diagnosis and therapeutics of CNS disorders as a basis for future research.

Osteoporosis in Rheumatic Diseases

Osteoporosis is a chronic disease characterized by an increased risk of fragility fracture. Patients affected by rheumatic diseases are at greater risk of developing osteoporosis. The purpose of the present review is to discuss the pathogenesis, epidemiology, and treatment of osteoporosis in patients affected by rheumatic diseases with special focus for rheumatoid arthritis, psoriatic arthritis, spondyloarthritis, systemic lupus erythematosus, systemic sclerosis, vasculitides, Sjogren syndrome, and crystal-induced arthritis.

The Role of Osteoprotegerin in Vascular Calcification and Bone Metabolism: The Basis for Developing New Therapeutics

Osteoporosis (OP) and cardiovascular diseases (CVD) are both important causes of mortality and morbidity in aging patients. There are common mechanisms underlying the regulation of bone remodeling and the development of smooth muscle calcification; a temporal relationship exists between osteoporosis and the imbalance of mineral metabolism in the vessels. Vascular calcification appears regulated by mechanisms that include both inductive and inhibitory processes. Multiple factors are implicated in both bone and vascular metabolism. Among these factors, the superfamily of tumor necrosis factor (TNF) receptors including osteoprotegerin (OPG) and its ligands has been established. OPG is a soluble decoy receptor for receptor activator of nuclear factor-kB ligand (RANKL) and TNF-related apoptosis-inducing ligand (TRAIL). OPG binds to RANKL and TRAIL, and inhibits the association with their receptors, which have been labeled as the receptor activator of NF-kB (RANK). Sustained release of OPG from vascular endothelial cells (ECs) has been demonstrated in response to inflammatory proteins and cytokines, suggesting that OPG/RANKL/RANK system plays a modulatory role in vascular injury and inflammation. For the development of potential therapeutic strategies targeting vascular calcification, critical consideration of the implications for bone metabolism must be taken into account to prevent potentially detrimental effects to bone metabolism.

The Role of Osteoprotegerin and Its Ligands in Vascular Function

The superfamily of tumor necrosis factor (TNF) receptors includes osteoprotegerin (OPG) and its ligands, which are receptor activators of nuclear factor kappa-B ligand (RANKL) and TNF-related apoptosis-inducing ligand (TRAIL). The OPG/RANKL/RANK system plays an active role in pathological angiogenesis and inflammation as well as cell survival. It has been demonstrated that there is crosstalk between endothelial cells and osteoblasts during osteogenesis, thus establishing a connection between angiogenesis and osteogenesis. This OPG/RANKL/RANK/TRAIL system acts on specific cell surface receptors, which are then able to transmit their signals to other intracellular components and modify gene expression. Cytokine production and activation of their receptors induce mechanisms to recruit monocytes and neutrophils as well as endothelial cells. Data support the role of an increased OPG/RANKL ratio as a possible marker of progression of endothelial dysfunction in metabolic disorders in relationship with inflammatory marker levels. We review the role of the OPG/RANKL/RANK triad in vascular function as well as molecular mechanisms related to the etiology of vascular diseases. The potential therapeutic strategies may be very promising in the future.

Identification and characterization of a T-2 toxin-producingFusarium poaestrain and the anti-tumor effect of the T-2 toxin on human hepatoma cell line SMMC-7721

T-2 toxin, produced by Fusarium moulds, is a type A trichothecene mycotoxin which is known to inhibit protein synthesis and also reported to induce DNA lesions, potentially causing DNA fragmentation. T-2 toxin is a very potent cytotoxic toxin, which displays anti-tumor properties. Nevertheless, more studies are still needed to explore its antitumor mechanisms as well as its clinical application in cancer treatment. Here, we report the identification and characterization of a T-2 toxin produced by a Fusarium poae isolated from Jilin, Northeast China. 17 strains of Fusarium poae were screened for T-2 toxin-production and one strain with the highest yield was selected further studies. T-2 toxin produced by the selected Fusarium poae was isolated and purified by HPLC. Anticancer properties of the purified T-2 toxin were evaluated with human hepatoma cell SMMC-7721. The purified T-2 toxin inhibits the proliferation of SMMC-7721 cells and induces cell apoptosis. The mitochondrial membrane potential decreased and the intracellular ROS was up-regulated after T-2 treatment of the cells. Further studies revealed that T-2 treatment activates the intrinsic mitochondrial and MAPKs pathway. Our data provide insight into the promising application of the T-2 toxin in cancer treatment.

T-2 toxin produced by Fusarium poae strain can induces apoptosis in SMMC-7721 cells.

The temporal pattern of immune and inflammatory proteins prior to a recurrent coronary event in post-acute coronary syndrome patients

PURPOSE

We assessed the temporal pattern of 29 immune and inflammatory proteins in post-acute coronary syndrome (ACS) patients, prior to the development of recurrent ACS.

METHODS

High-frequency blood sampling was performed in 844 patients admitted for ACS during one-year follow-up. We conducted a case-control study on the 45 patients who experienced reACS (cases) and two matched event-free patients (controls) per case. Olink Proteomics' immunoassay was used to obtain serum levels of the 29 proteins, expressed in an arbitrary unit on the log2-scale (Normalized Protein eXpression, NPX). Linear mixed-effects models were applied to examine the temporal pattern of the proteins, and to illustrate differences between cases and controls.

RESULTS

Mean age was 66 ± 12 years and 80% were men. Cases and controls had similar baseline clinical characteristics. During the first 30 days, and after multiple testing correction, cases had significantly higher serum levels of CXCL1 (difference of 1.00 NPX, p = 0.002), CD84 (difference of 0.64 NPX, p = 0.002) and TNFRSF10A (difference of 0.41 NPX, p < 0.001) than controls. After 30 days, serum levels of all 29 proteins were similar in cases and controls. In particular, no increase was observed prior to reACS.

CONCLUSIONS

Among 29 immune and inflammatory proteins, CXCL1, CD84 and TNFRSF10A were associated with early reACS after initial ACS-admission.

Decreased serum TRAIL is associated with increased mortality in smokers with comorbid emphysema and coronary artery disease

BACKGROUND

Smokers are highly susceptible to lung and cardiovascular disease that can reduce their survival. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a protein in the circulation that may suppress vascular and pulmonary inflammation. Therefore, we hypothesized that diminished circulating TRAIL levels would be associated with poor survival in smokers with lung and cardiovascular disease.

METHODS

Serum TRAIL level was measured by immunoassay in 474 smokers. Coronary atherosclerosis was assessed by coronary artery calcium scoring along with emphysema, lung function, and survival.

RESULTS

The 474 smokers were 65.7 ± 6.3 years old and 52.2% male with 55.3 ± 31.5 pack-years of tobacco-exposure. 83 of them died during 3588.2 person-years of follow up. At baseline, lower TRAIL level was associated with more coronary artery calcium (OR = 1.2 per SD, 95%CI 1.1-1.5, p = 0.02), and with history of myocardial infarction (OR = 2.3 per SD, 95%CI 1.2-4.5, p = 0.02), angina (OR = 1.6 per SD, 95%CI 1.1-2.6, p = 0.03), and angioplasty (OR = 1.8 per SD, 95%CI 1.0-3.1, p = 0.04) in models adjusted for cardiovascular risk-factors, FEV₁, and emphysema. Also, lower TRAIL level was associated with emphysema severity independent of demographics and tobacco exposure (β = 0.11 sq. root units, 95% CI 0.01-0.22, p = 0.03). Further, TRAIL level was lowest in smokers with comorbid emphysema and coronary artery calcification rather than either condition alone. Finally, lower TRAIL level was independently associated with increased mortality in smokers particularly in those with comorbid emphysema and coronary artery calcification (HR = 1.38, 95% CI 1.01-1.90).

CONCLUSIONS

TRAIL level is reduced in smokers with comorbid emphysema and coronary artery disease, and is associated with reduced survival.

Osteoprotegerin and Cardiovascular Events in High-Risk Populations: Meta-Analysis of 19 Prospective Studies Involving 27 450 Participants

Background Osteoprotegerin is a cytokine involved in bone metabolism as well as vascular calcification and atherogenesis. Although circulating osteoprotegerin levels are robustly associated with incident cardiovascular disease ( CVD ) in the general population, its relevance as a biomarker among populations at high CVD risk is less clear. Methods and Results Three independent reviewers systematically searched PubMed, EMBASE , and Web of Science to identify prospective studies that had recruited participants on the basis of having conditions related to high CVD risk. A total of 19 studies were eligible for inclusion, reporting on 27 450 patients with diabetes mellitus (2 studies), kidney disease (7 studies), preexisting heart disease (5 studies), or recent acute coronary syndromes (5 studies) at baseline. Over a mean follow-up of 4.2 years, 4066 CVD events were recorded. In a random-effects meta-analysis, the pooled risk ratio for CVD events comparing people in the top versus the bottom tertile of osteoprotegerin concentration was 1.30 (95% confidence interval, 1.12-1.50; P<0.001; I2=68.3%). There was evidence for presence of publication bias ( P value from Egger's test=0.013). Correction for publication bias using the trim-and-fill method reduced the risk ratio to 1.21 (95% confidence interval, 1.03-1.42; P<0.001). The risk ratios did not vary significantly by population type, geographical region, statistical adjustment, sample or assay type, age, sex, or length of follow-up. Conclusions In populations at high CVD risk, elevated circulating osteoprotegerin levels are associated with a higher risk for future CVD events. The magnitude of association appears weaker than in the general population.

Effects of Hypoxia and Bed Rest on Markers of Cardiometabolic Risk: Compensatory Changes in Circulating TRAIL and Glutathione Redox Capacity

In chronic diseases, hypoxia and physical inactivity are associated with atherosclerosis progression. In contrast, a lower mortality from coronary artery disease and stroke is observed in healthy humans residing at high altitude in hypoxic environments. Eleven young, male volunteers completed the following 10-day campaigns in a randomized order: hypoxic ambulatory, hypoxic bed rest and normoxic bed rest. Before intervention, subjects were evaluated in normoxic ambulatory condition. Normobaric hypoxia was achieved in a hypoxic facility simulating 4000 m of altitude. Following hypoxia, either in bed rest or ambulatory condition, markers of cardiometabolic risk shifted toward a more atherogenic pattern consisting of: (a) lower levels of total HDL cholesterol and HDL2 sub-fraction and decreased hepatic lipase; (b) activation of systemic inflammation, as determined by C-reactive protein and serum amyloid A; (c) increased plasma homocysteine; (d) decreased delta-5 desaturase index in cell membrane fatty acids, a marker of insulin sensitivity. Bed rest and hypoxia additively decreased total HDL and delta-5 desaturase index. In parallel to the pro-atherogenic effects, hypoxia activated selected anti-atherogenic pathways, consisting of increased circulating TNF-related apoptosis-inducing ligand (TRAIL), a protective factor against atherosclerosis, membrane omega-3 index and erythrocyte glutathione availability. Hypoxia mediated changes in TRAIL concentrations and redox glutathione capacity (i.e., GSH/GSSG ratio) were greater in ambulatory conditions (+34 ± 6% and +87 ± 31%, respectively) than in bed rest (+17 ± 7% and +2 ± 27% respectively). Hypoxia-induced cardiometabolic risk is blunted by moderate level of physical activity as compared to bed rest. TRAIL and glutathione redox capacity may contribute to the positive interaction between physical activity and hypoxia.

Highlights:

– Hypoxia and bed rest activate metabolic and inflammatory markers of atherogenesis.

– Hypoxia and physical activity activate selected anti-atherogenic pathways.

– Hypoxia and physical activity positive interaction involves TRAIL and glutathione.

TRAIL and Ceruloplasmin Inverse Correlation as a Representative Crosstalk between Inflammation and Oxidative Stress

Objective

“Oxinflammation” is a recently coined term that defines the deleterious crosstalk between inflammatory and redox systemic processes, which underlie several diseases. Oxinflammation could be latently responsible for the predisposition of certain healthy individuals to disease development. The oxinflammatory pathway has been recently suggested to play a crucial role in regulating the activity of TNF-related apoptosis-inducing ligand (TRAIL), a TNF superfamily member that can mediate multiple signals in physiological and pathological processes. Therefore, we investigated the associations between TRAIL and key players of vascular redox homeostasis.

Methods

We measured circulating TRAIL levels relative to praoxonas-1, lipoprotein phospholipase-A2, and ceruloplasmin levels in a cohort of healthy subjects (n = 209).

Results

Multivariate analysis revealed that ceruloplasmin levels were significantly inversely associated with TRAIL levels (r = −0.431, p < 0.001). The observed association retained statistical significance after adjustment for additional confounding factors. After stratification for high-sensitivity C-reactive protein levels, the inverse association between TRAIL and ceruloplasmin levels remained strong and significant (r = −0.508, p < 0.001, R² = 0.260) only in the presence of inflammation, confirming the role of inflammation as emerged in in vitro experiments where recombinant TRAIL decreased ceruloplasmin expression levels in TNF-treated PBMC cultures.

Conclusion

The results indicated that in an inflammatory milieu, TRAIL downregulates ceruloplasmin expression, highlighting a signaling axis involving TRAIL and ceruloplasmin that are linked via inflammation and providing important insights with potential clinical implications.

The role of OPG/RANKL in the pathogenesis of diabetic cardiovascular disease

Cardiovascular (CV) disease is the leading cause of mortality in patients with type 2 diabetes mellitus. A major factor in the pathogenesis of CV disease is vascular calcification (VC), which is accelerated in type 2 diabetes mellitus. Calcification of the vessel wall contributes to vascular stiffness and left ventricular hypertrophy whereas intimal calcification may predispose to plaque rupture and CV death. The pathogenesis of VC is complex but appears to be regulated by the osteoprotegerin (OPG)/receptor activator of nuclear factor-κB ligand (RANKL) signaling pathway, which is involved in bone remodeling. Within the bone, OPG prevents RANKL from binding to receptor activator of nuclear factor-κB and inhibiting bone resorption. Outside of the bone, the clinical significance of OPG blocking RANKL is not well understood, but OPG knockout mice that lack OPG develop early and severe VC. This minireview outlines some of the research on OPG/RANKL in the pathogenesis of VC and discusses potential therapies, which may reduce VC and CV burden in humans.

Activation of the non-canonical NF-κB/p52 pathway in vascular endothelial cells by RANKL elicits pro-calcific signalling in co-cultured smooth muscle cells

BACKGROUND

The intimal endothelium is known to condition the underlying medial smooth muscle cell (SMC) layer of the vessel wall, and is highly responsive to receptor-activator of nuclear factor-κB ligand (RANKL) and tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), pro-calcific and anti-calcific agents, respectively. In this paper, we tested the hypothesis that RANKL-induced activation of endothelial NF-κB signalling is essential for pro-calcific activation of the underlying SMCs.

METHODS

For these studies, human aortic endothelial and smooth muscle cell mono-cultures (HAECs, HASMCs) were treated with RANKL (0-25 ng/ml ± 5 ng/ml TRAIL) for 72 h. Non-contact transwell HAEC:HASMC co-cultures were also employed in which the luminal HAECs were treated with RANKL (± 5 ng/ml TRAIL), followed by analysis of pro-calcific markers in the underlying subluminal HASMCs.

RESULTS

Treatment of either HAECs or HASMCs with RANKL activated the non-canonical NF-κB/p52 and canonical NF-κB/p65 pathways in both cell types. In RANKL ± TRAIL-treated HAECs, recombinant TRAIL, previously demonstrated by our group to strongly attenuate the pro-calcific signalling effects of RANKL, was shown to specifically block the RANKL-mediated activation of non-canonical NF-κB/p52, clearly pointing to the mechanistic relevance of this specific pathway to RANKL function within endothelial cells. In a final series of HAEC:HASMC transwell co-culture experiments, RANKL treatment of HAECs that had been genetically silenced (via siRNA) for the NF-κB2 gene (the molecular forerunner to NF-κB/p52 generation) exhibited strongly attenuated pro-calcific activation of underlying HASMCs relative to scrambled siRNA controls.

SUMMARY

These in vitro observations provide valuable mechanistic insights into how RANKL may potentially act upon endothelial cells through activation of the alternative NF-κB pathway to alter endothelial paracrine signalling and elicit pro-calcific responses within underlying vascular smooth muscle cells.

NDV entry into dendritic cells through macropinocytosis and suppression of T lymphocyte proliferation

Newcastle disease virus (NDV) causes major economic losses in the poultry industry. Previous studies have shown that NDV utilizes different pathways to infect various cells, including dendritic cells (DCs). Here, we demonstrate that NDV gains entry into DCs mainly via macropinocytosis and clathrin-mediated endocytosis. The detection of cytokines interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-12 (IL-12), interleukin-4 (IL-4) and interleukin-10 (IL-10) indicates that NDV significantly induces Th1 responses and lowers Th2 responses. Furthermore, NDV entry into DCs resulted in the upregulation of TNF-related apoptosis-inducing ligand (TRAIL) and cleaved caspase-3 proteins, which in turn activated the extrinsic apoptosis pathway and induced DCs apoptosis. Transwell® co-culture demonstrated that direct contact between live NDV-stimulated DCs and T cells, rather than heated-inactivated NDV, inhibited CD4⁺ T cell proliferation. Taken together, these findings provide new insights into the mechanism underlying NDV infections, particularly in relation to antigen presentation cells and suppression of T cell proliferation.

Lower maternal serum tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) levels in early preeclampsia. A retrospective study

OBJECTIVE

To determine whether maternal serum concentrations of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a cytokine with anti-inflammatory activity, also involved in cardiovascular morbidity, differ between women with early preeclampsia (<34 weeks) and those with uncomplicated pregnancies.

STUDY DESIGN

This nested case control study included 40 women carrying a single fetus with an uncomplicated pregnancy and 20 women with early preeclampsia (<34 weeks). Data were matched 1:2 for gestational age at the time of venipuncture (28-34 weeks of gestation), converted into multiples of the median and adjusted for maternal weight. The maternal serum TRAIL concentrations were determined using an enzyme immunoassay.

RESULTS

The TRAIL concentrations were lower in the patients with early preeclampsia when compared with those of the control group, being 29.64 ± 8.83 pg/dL and 43.8 ± 12.53 pg/dL (p-value < 0.001), respectively. The difference was also present after multiple of median conversion and maternal weight adjustment. The quoted multiple of median values were 1.00 ± 0.27 and 0.82 ± 0.23, respectively (p-value < 0.001).

CONCLUSIONS

Serum TRAIL concentrations are significantly reduced in patients with early preeclampsia. This result is in line with the presence of an intravascular inflammation typical of preeclampsia. The lower levels of TRAIL detected in preeclampsia should be useful for a more proper selection of women with long-term cardiovascular risk later in life.

TRAIL attenuates RANKL-mediated osteoblastic signalling in vascular cell mono-culture and co-culture models

Background and objectives

Vascular calcification (VC) is a major risk factor for elevated cardiovascular morbidity/mortality. Underlying this process is osteoblastic signalling within the vessel wall involving complex and interlinked roles for receptor-activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), and tumour necrosis factor-related apoptosis-inducing ligand (TRAIL). RANKL promotes vascular cell osteoblastic differentiation, whilst OPG acts as a neutralizing decoy receptor for RANKL (and TRAIL). With respect to TRAIL, much recent evidence points to a vasoprotective role for this ligand, albeit via unknown mechanisms. In order to shed more light on TRAILs vasoprotective role therefore, we employed in vitro cell models to test the hypothesis that TRAIL can counteract the RANKL-mediated signalling that occurs between the vascular cells that comprise the vessel wall.

Methods and results

Human aortic endothelial and smooth muscle cell mono-cultures (HAECs, HASMCs) were treated with RANKL (0–25 ng/mL ± 5 ng/mL TRAIL) for 72 hr. Furthermore, to better recapitulate the paracrine signalling that exists between endothelial and smooth muscle cells within the vessel wall, non-contact transwell HAEC:HASMC co-cultures were also employed and involved RANKL treatment of HAECs (±TRAIL), subsequently followed by analysis of pro-calcific markers in the underlying subluminal HASMCs. RANKL elicited robust osteoblastic signalling across both mono- and co-culture models (e.g. increased BMP-2, alkaline phosphatase/ALP, Runx2, and Sox9, in conjunction with decreased OPG). Importantly, several RANKL actions (e.g. increased BMP-2 release from mono-cultured HAECs or increased ALP/Sox9 levels in co-cultured HASMCs) could be strongly blocked by co-incubation with TRAIL. In summary, this paper clearly demonstrates that RANKL can elicit pro-osteoblastic signalling in HAECs and HASMCs both directly and across paracrine signalling axes. Moreover, within these contexts we present clear evidence that TRAIL can block several key signalling actions of RANKL in vascular cells, providing further evidence of its vasoprotective potential.

Redox signaling and oxidative stress: Cross talk with TNF-related apoptosis inducing ligand activity

Redox regulation plays a key role in several physiopathological contexts and free radicals, from nitric oxide and superoxide anion up to other forms of reactive oxygen species (ROS), have been demonstrated to be involved in different biological and regulatory processes. The data reported in the current literature describe a link between ROS, inflammation and programmed cell death that is attracting interest as new pathways to be explored and targeted for therapeutic purposes. In this light, there is also growing attention to the involvement of this link in the activity of the TNF-related apoptosis inducing ligand (TRAIL). TRAIL is a member of the TNF ligands super family able to mediate multiple intracellular signals, with the potential to lead to a range of biological effects in different cell types. In particular, the hallmark of TRAIL is the ability to induce selective apoptosis in transformed cells leaving normal cells almost unaffected and this feature has already opened the door to several clinical studies for cancer treatment. Moreover, TRAIL plays a role in several physiological and pathological processes of both innate and adaptive immune systems and of the cardiovascular context, with a strong clinical potential. Nonetheless, several issues still need to be clarified about the signaling mediated by TRAIL to gain deeper insight into its therapeutic potential. In this light, the aim of this review is to summarize the main preclinical evidences about the interplay between TRAIL and redox signaling, with particular emphasis to the implications in vascular physiopathology and cancer.