Tumor necrosis factor-related apoptosis-inducing ligand enhances collagen production by human lung fibroblasts

Analysing the relevance of TGF-β and its regulators in cervical cancer to identify therapeutic and diagnostic markers

The role of transforming growth factor-beta (TGF-β) is dual, such that, it inhibits tumor development in initial stage and promotes metastasis in later stage. The present study is aimed to analyse the relevance of different types of TGF-β and their receptors on the overall survival (OS) and TGF-β driven gene expression in individuals with cervical cancer (CC) using ONCODB and GEPIA databases. The in-silico gene expression analysis showed, TGF-β1 and TGFβR2 are upregulated in cells infected with human papilloma virus (HPV)16, whereas, TGF-β2, TGFβR1 and TGFβR3 expression were downregulated. In HPV 18 infected cells, TGF-β1, TGF-β2 and TGFβR1 were downregulated, meanwhile, TGF-β3, TGFβR2 and TGFβR3 were upregulated. OS analysis of CC patients with different TGF-β expression revealed that, TGF-β1, TGF-β2, TGF-β3 and TGFβR2 were associated with reduced survival rate. Further, we identified four microRNAs (miRNAs) (hsa-miR-21-5p, hsa-miR-29b-3p, hsa-miR-101-3p and hsa-miR-130a-3p) interacted favorably with TGF-β in HPV 16 and 18 positive samples using MIENTURNET. This present review further emphasizes that, targeting TGF-β could be a novel and futuristic approach for CC management and therapeutics.

TRAIL and its receptors in cardiac diseases

Cardiovascular disease is a leading cause of death worldwide. Loss of cardiomyocytes that occurs during many types of damage to the heart such as ischemic injury and stress caused by pressure overload, diminishes cardiac function due to their limited regenerative capacity and promotes remodeling, which further damages the heart. Cardiomyocyte death occurs through two primary mechanisms, necrosis and apoptosis. Apoptosis is a highly regulated form of cell death that can occur through intrinsic (mitochondrial) or extrinsic (receptor mediated) pathways. Extrinsic apoptosis occurs through a subset of Tumor Necrosis Receptor (TNF) family receptors termed "Death Receptors." While some ligands for death receptors have been extensively studied in the heart, such as TNF-α, others have been virtually unstudied. One poorly characterized cardiac TNF related ligand is TNF-Related Apoptosis Inducing Ligand (TRAIL). TRAIL binds to two apoptosis-inducing receptors, Death Receptor (DR) 4 and DR5. There are also three decoy TRAIL receptors, Decoy Receptor (DcR) 1, DcR2 and osteoprotegerin (OPG). While TRAIL has been extensively studied in the cancer field due to its ability to selectively induce apoptosis in transformed cell types, emerging clinical evidence points towards a role for TRAIL and its receptors in cardiac pathology. This article will highlight our current understanding of TRAIL and its receptors in normal and pathological conditions in the heart.

The matricellular protein CCN3 supports lung endothelial homeostasis and function

Aberrant vascular remodeling contributes to the progression of many aging-associated diseases, including idiopathic pulmonary fibrosis (IPF), where heterogeneous capillary density, endothelial transcriptional alterations, and increased vascular permeability correlate with poor disease outcomes. Thus, identifying disease-driving mechanisms in the pulmonary vasculature may be a promising strategy to limit IPF progression. Here, we identified Ccn3 as an endothelial-derived factor that is upregulated in resolving but not in persistent lung fibrosis in mice, and whose function is critical for vascular homeostasis and repair. Loss and gain of function experiments were carried out to test the role of CCN3 in lung microvascular endothelial function in vitro through RNAi and the addition of recombinant human CCN3 protein, respectively. Endothelial migration, permeability, proliferation, and in vitro angiogenesis were tested in cultured human lung microvascular endothelial cells (ECs). Loss of CCN3 in lung ECs resulted in transcriptional alterations along with impaired wound-healing responses, in vitro angiogenesis, barrier integrity as well as an increased profibrotic activity through paracrine signals, whereas the addition of recombinant CCN3 augmented endothelial function. Altogether, our results demonstrate that the matricellular protein CCN3 plays an important role in lung endothelial function and could serve as a promising therapeutic target to facilitate vascular repair and promote lung fibrosis resolution.

The potential of biomarkers of fibrosis in chronic lung allograft dysfunction

Chronic lung allograft dysfunction (CLAD) is the major long-term cause of morbidity and mortality after lung transplantation. Both bronchiolitis obliterans syndrome and restrictive lung allograft syndrome, two main types of CLAD, lead to fibrosis in either the small airways or alveoli and pleura. Pathological pathways in CLAD and other types of fibrosis, for example idiopathic pulmonary fibrosis, are assumed to overlap and therefore fibrosis biomarkers could aid in the early detection of CLAD. These biomarkers could help to differentiate between different phenotypes of CLAD and could, in comparison to biomarkers of inflammation, possibly distinguish an infectious event from CLAD when a decline in lung function is present. This review gives an overview of known CLAD specific biomarkers, describes new promising fibrosis biomarkers currently investigated in other types of fibrosis, and discusses the possible use of these fibrosis biomarkers for CLAD.

Disruption of Osteoprotegerin has complex effects on medial destruction and adventitial fibrosis during mouse abdominal aortic aneurysm formation

Aortic aneurysm refers to dilatation of the aorta due to loss of elasticity and degenerative weakening of its wall. A preventive role for osteoprotegerin (Opg) in the development of abdominal aortic aneurysm has been reported in the CaCl₂-induced aneurysm model, whereas Opg was found to promote suprarenal aortic aneurysm in the AngII-induced ApoE knockout mouse aneurysm model. To determine whether there is a common underlying mechanism to explain the impact of Opg deficiency on the vascular structure of the two aneurysm models, we analyzed suprarenal aortic tissue of 6-month-old ApoE^-/-Opg^-/- mice after AngII infusion for 28 days. Less aortic dissection and aortic lumen dilatation, more adventitial thickening, and higher expression of collagen I and Trail were observed in ApoE^-/-Opg^-/- mice relative to ApoE^-/-Opg^+/+ mice. An accumulation of α-smooth muscle actin and vimentin double-positive myofibroblasts was noted in the thickened adventitia of ApoE^-/-Opg^-/- mice. Our results suggest that fibrotic remodeling of the aorta induced by myofibroblast accumulation might be an important pathological event which tends to limit AngII-induced aortic dilatation in ApoE^-/-Opg^-/- mice.

TRAIL signals, extracellular matrix and vessel remodelling

The extracellular matrix (ECM) is an essential part of the vasculature, not only providing structural support to the blood vessel wall, but also in its ability to interact with cells to regulate cell phenotype and function including proliferation, migration, differentiation and death – processes important in vascular remodelling. Increasing evidence implicates TNF-related apoptosis-inducing ligand (TRAIL) signalling in the modulation of vascular cell function and remodelling under normal and pathological conditions such as in atherosclerosis. TRAIL can also stimulate synthesis of multiple ECM components within blood vessels. This review explores the relationship between TRAIL signals, the ECM, and its implications in vessel remodelling in cardiovascular disease.

Collagen Quantification in Tissue Specimens

Collagen is the major extracellular protein in mammals. Accurate quantification of collagen is essential in the biomaterials (e.g., reproducible collagen scaffold fabrication), drug discovery (e.g., assessment of collagen in pathophysiologies, such as fibrosis), and tissue engineering (e.g., quantification of cell-synthesized collagen) fields. Although measuring hydroxyproline content is the most widely used method to quantify collagen in biological specimens, the process is very laborious. To this end, the Sircol™ Collagen Assay is widely used due to its inherent simplicity and convenience. However, this method leads to overestimation of collagen content due to the interaction of Sirius red with basic amino acids of non-collagenous proteins. Herein, we describe the addition of an ultrafiltration purification step in the process to accurately determine collagen content in tissues.

Tumor necrosis factor-related apoptosis-inducing ligand regulates hallmark features of airways remodeling in allergic airways disease

Allergic asthma is a complex disease characterized by acute inflammation of the airways that over time leads to the development of significant structural changes termed remodeling. TNF-related apoptosis-inducing ligand (TRAIL) has an important regulatory role in acute allergic airways inflammation through up-regulation of the E3 ubiquitin ligase Midline-1 (MID-1), which limits protein phosphatase 2A (PP2A) activity and downstream dephosphorylation of proinflammatory signaling molecules. The relevance of TRAIL in the development of airways remodeling has yet to be determined. In this study, the lungs of wild-type (WT) BALB/c and Tnfsf10 knockout (TRAIL-/-) mice were chronically exposed to ovalbumin (OVA) for 12 weeks to induce hallmark features of chronic allergic airways disease, including airways hyperreactivity (AHR), subepithelial collagen deposition, goblet cell hyperplasia, and smooth muscle hypertrophy. TRAIL-/- mice were largely protected from the development of AHR and peribronchial eosinophilia and had reduced levels of mast cells in the airways. This correlated with lower levels of cytokines, including IL-4, -5, -10, and -13, and with lower levels of proinflammatory chemokines from cultured cells isolated from the draining lymph nodes. TRAIL-/- mice were also protected from the characteristic features of airways remodeling, including peribronchial fibrosis, smooth muscle hypertrophy, and mucus hypersecretion, which correlated with reduced TGF-β1 levels in the lungs. MID-1 expression was reduced in TRAIL-/- mice and up-regulated in allergic WT mice. Raising PP2A activity using 2-amino-4-(4-heptyloyphenol)-2-methylbutan-1-ol in allergic WT mice reduced eosinophilia, TGF-β1, and peribronchial fibrosis. This study shows that TRAIL promotes airways remodeling in an OVA-induced model of chronic allergic airways disease. Targeting TRAIL and its downstream proinflammatory signaling pathway involving PP2A may be of therapeutic benefit in reducing the hallmark features of airways remodeling observed in chronic allergic airways inflammation.

The tumor necrosis factor superfamily in heart failure

Numerous clinical studies have established that tumor necrosis factor (TNF)-alpha may play a pathogenic role in the development and progression of heart failure (HF). Recent reports suggest that other ligands in the TNF superfamily could also play a pathogenic role in chronic HF. TNF superfamily ligands are expressed predominantly by cells in the immune system, while the TNF receptor superfamily are expressed by a wide variety of cells, including myocardial cells. Several pathways are activated by ligand-receptor interactions, but of particular importance is the nuclear factor (NF)-kappaB pathway which is activated in the failing human heart. All ligands in the TNF superfamily have the potential to activate NF-kappaB, leading to transcription of genes involved in apoptosis, cell survival, proliferation, inflammation and hypertrophic signaling in cardiomyocytes. Among several TNF superfamily members that are activated in HF, the authors' have recentlyshown that CD40L-CD40 and OPG-RANK-RANKL interactions may be implicated in the pathogenesis of HF through different mechanisms, possibly representing new targets for therapy in this disorder.

The possible role of trauma in skin tags through the release of mast cell mediators

Background:

Skin tags (ST) are common benign tumors of the skin but their etiopathogenesis is not well understood. STs arise in sites subjected to trauma. It was proved that mast cells are recruited to sites of skin trauma and increase their tumor necrosis factor-α (TNF-α) content.

Aim:

STs are linked to obesity and frictional sites, but this has not been studied at the molecular level. We hypothesized that mast cells, TNF-α and its family member, TNF-related apoptosis-inducing ligand (TRAIL) might play a role in the pathogenesis of STs as a response to trauma.

Materials and Methods:

A study was done on 15 patients with STs. Two STs and a snip of normal skin were obtained in each subject. We counted the mast cells after Toluidine blue staining. Enzyme-linked immunosorbant assay was used to measure TNF-α level while reverse transcriptase polymerase chain reaction was used to evaluate the level of TRAIL mRNA expression.

Results:

Mast cell count in all STs was significantly higher than that in control (P=0.0355). There was a highly significant increase in the level of TNF-α in all STs as compared to its level in controls (P<0.0001). Expression of TRAIL mRNA was significantly higher in STs as compared to its expression in controls (P<0.0001).

Conclusion:

Our study suggests that mast cells, TNF-α and TRAIL may play a role in the pathogenesis of STs.

Deficiency of tumour necrosis factor-related apoptosis-inducing ligand exacerbates lung injury and fibrosis

BACKGROUND

The death receptor ligand tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) shows considerable clinical promise as a therapeutic agent. TRAIL induces leukocyte apoptosis, reducing acute inflammatory responses in the lung. It is not known whether TRAIL modifies chronic lung injury or whether TRAIL has a role in human idiopathic pulmonary fibrosis (IPF). We therefore explored the capacity of TRAIL to modify chronic inflammatory lung injury and studied TRAIL expression in patients with IPF.

METHODS

TRAIL(-/-) and wild-type mice were instilled with bleomycin and inflammation assessed at various time points by bronchoalveolar lavage and histology. Collagen deposition was measured by tissue hydroxyproline content. TRAIL expression in human IPF lung samples was assessed by immunohistochemistry and peripheral blood TRAIL measured by ELISA.

RESULTS

TRAIL(-/-) mice had an exaggerated delayed inflammatory response to bleomycin, with increased neutrophil numbers (mean 3.19±0.8 wild type vs 11.5±5.4×10(4) TRAIL(-/-), p<0.0001), reduced neutrophil apoptosis (5.42±1.6% wild type vs 2.47±0.5% TRAIL(-/-), p=0.0003) and increased collagen (3.45±0.2 wild type vs 5.8±1.3 mg TRAIL(-/-), p=0.005). Immunohistochemical analysis showed induction of TRAIL in bleomycin-treated wild-type mice. Patients with IPF demonstrated lower levels of TRAIL expression than in control lung biopsies and their serum levels of TRAIL were significantly lower compared with matched controls (38.1±9.6 controls vs 32.3±7.2 pg/ml patients with IPF, p=0.002).

CONCLUSION

These data suggest TRAIL may exert beneficial, anti-inflammatory actions in chronic pulmonary inflammation in murine models and that these mechanisms may be compromised in human IPF.

Sensitivity of intestinal fibroblasts to TNF-related apoptosis-inducing ligand-mediated apoptosis in Crohn's disease

OBJECTIVE

Strictures and fistulas are common complications of Crohn's disease (CD). Collagen deposit and fibroblast proliferation can contribute to their development. Tumour necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) binds two pro-apoptotic (TRAIL-R1, TRAIL-R2) and three anti-apoptotic (TRAIL-R3, TRAIL-R4, osteoprotegerin (OPG)) receptors. The aim of this work was to study TRAIL expression and the effects on intestinal fibroblasts (IFs) in CD.

MATERIAL AND METHODS

Intestinal samples from 25 CD (with or without fibrostenosing areas) and 38 control patients (with or without inflammation) were used. TRAIL, TRAIL R2 and TRAIL R3 expression in the intestine and in human IFs was studied by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and immunostaining in IF and intestinal samples. TRAIL-induced IF cell death was studied in the presence or absence of OPG and cytokines. Western blots for poly ADP-ribose polymerase (PARP) and caspase-8 were performed to confirm apoptosis in IFs.

RESULTS

Transcripts for TRAIL and its receptors were confirmed in the intestine. Immunostaining showed intestinal expression of TRAIL, TRAIL-R2 and TRAIL-R3 in fibroblasts, immune cells and epithelial cells, mainly in fibrostenosing areas. TRAIL-R3 mRNA expression was lower in IFs from fibrostenosing CD. The sensitivity of IFs to TRAIL-mediated apoptosis was higher in the fibrostenosing areas of CD. The effect of TRAIL was decreased by IL-6 and its soluble receptor and almost completely reversed by OPG in the CD patients involved.

CONCLUSIONS

TRAIL is expressed in the intestine and influences fibroblast survival. Variations in TRAIL expression and in TRAIL-mediated apoptosis could be involved in the tissue remodelling associated with CD.

T cell TRAIL promotes murine lupus by sustaining effector CD4 Th cell numbers and by inhibiting CD8 CTL activity

T cells play an essential role in driving humoral autoimmunity in lupus. Molecules such as TRAIL exhibit strong T cell modulatory effects and are up-regulated in lupus, raising the possibility that they may influence disease severity. To address this possibility, we examined the role of TRAIL expression on pathogenic T cells in an induced model of murine lupus, the parent-into-F(1) (P-->F(1)) model of chronic graft-vs-host disease (GVHD), using wild-type or TRAIL-deficient donor T cells. Results were compared with mice undergoing suppressive acute GVHD. Although chronic GVHD mice exhibited less donor T cell TRAIL up-regulation and IFN-alpha-inducible gene expression than acute GVHD mice, donor CD4(+) T cell TRAIL expression in chronic GVHD was essential for sustaining effector CD4(+) Th cell numbers, for sustaining help to B cells, and for more severe lupus-like renal disease development. Conversely, TRAIL expression on donor CD8(+) T cells had a milder, but significant down-regulatory effect on CTL effector function, affecting the perforin/granzyme pathway and not the Fas ligand pathway. These results indicate that, in this model, T cell-expressed TRAIL exacerbates lupus by the following: 1) positively regulating CD4(+) Th cell numbers, thereby sustaining T cell help for B cells, and 2) to a lesser degree by negatively regulating perforin-mediated CD8(+) CTL killing that could potentially eliminate activated autoreactive B cells.

Following the TRAIL to apoptosis

Apoptosis, programmed cell death, eliminates injured or harmful cells. It can mediate its response through the actions of death ligands including TRAIL. TRAIL, a member of TNF superfamily, induces apoptosis of transformed cells through the action of death domain receptors DR-4 and DR5. It directly induces apoptosis through an extrinsic pathway, which involves the activation of caspases. TRAIL also is able to prevent apoptosis through the actions of its decoy receptors DcR-1 and DcR-2. Various regulators of TRAIL include FADD, IAPs, Bcl-2s, p53, and FLIPs. TRAIL is present in cells involved in asthma including eosinophils, mast cells, fibroblasts, and airway epithelial cells. It is expressed in airway remodeling and may be linked with the pathways of transforming growth factor-beta1, which is thought to cause damage to the epithelium. The repair process of the epithelium is hindered as a result of increased apoptosis induced by TGF-beta1, which overlaps with the pathways of TRAIL. Analogs of TRAIL could have therapeutical applications for asthma. TRAIL is also seen as the basis for a "miracle" drug for cancer because of its ability to selectively kill cancer cells.

Human mast cells undergo TRAIL-induced apoptosis

Mast cells (MC), supposedly long-lived cells, play a key role in allergy and are important contributors to other inflammatory conditions in which they undergo hyperplasia. In humans, stem cell factor (SCF) is the main regulator of MC growth, differentiation, and survival. Although human MC numbers may also be regulated by apoptotic cell death, there have been no reports concerning the role of the extrinsic apoptotic pathway mediated by death receptors in these cells. We examined expression and function of death receptors for Fas ligand and TRAIL in human MC. Although the MC leukemia cell line HMC-1 and human lung-derived MC expressed both Fas and TRAIL-R, MC lines derived from cord blood (CBMC) expressed only TRAIL-R. Activation of TRAIL-R resulted in caspase 3-dependent apoptosis of CBMC and HMC-1. IgE-dependent activation of CBMC increased their susceptibility to TRAIL-mediated apoptosis. Results suggest that TRAIL-mediated apoptosis may be a mechanism of regulating MC survival in vivo and, potentially, for down-regulating MC hyperplasia in pathologic conditions.

Molecular cloning, expression analysis and assignment of the porcine tumor necrosis factor superfamily member 10 gene (TNFSF10) to SSC13q34-->q36 by fluorescence in situ hybridization and radiation hybrid mapping

We have cloned the complete coding region of the porcine TNFSF10 gene. The porcine TNFSF10 cDNA has an ORF of 870 nucleotides and shares 85% identity with human TNFSF10, and 75% and 72% identity with rat and mouse Tnfsf10 coding sequences, respectively. The deduced porcine TNFSF10 protein consists of 289 amino acids with the calculated molecular mass of 33.5 kDa and a predicted pI of 8.15. The amino acid sequence similarities correspond to 86, 72 and 70% when compared with human, rat and mouse sequences, respectively. Northern blot analysis detected TNFSF10-specific transcripts (approximately 1.7 kb) in various organs of a 10-week-old pig, suggesting ubiquitous expression. Real-time RT-PCR studies of various organs from fetal (days 73 and 98) and postnatal stages (two weeks, eight months) demonstrated developmental and tissue-specific regulation of TNFSF10 mRNA abundance. The chromosomal location of the porcine TNFSF10 gene was determined by FISH of a specific BAC clone to metaphase chromosomes. This TNFSF10 BAC clone has been assigned to SSC13q34-->q36. Additionally, the localization of the TNFSF10 gene was verified by RH mapping on the porcine IMpRH panel.

Expression of TNF-related apoptosis-inducing ligand (TRAIL) in megakaryocytes and platelets

OBJECTIVE

Platelets are known to play an important role in hemostasis, thrombosis, wound healing, and inflammation. Platelet-induced modulation of inflammation and adaptive immune responses are mediated in part through tumor necrosis factor (TNF) family member ligands, including CD154, Fas ligand, and TNFalpha, that are expressed upon platelet activation. The present study investigated whether platelets and megakaryocytes also express TNF-related apoptosis-inducing ligand (TRAIL), another pro-apoptotic member of the TNF superfamily.

MATERIALS AND METHODS

Immunoprecipitation, enzyme-linked immunosorbent assay, and flow cytometry were used to assess TRAIL protein expression on isolated platelets, in vitro-derived megakaryocytes and premegakaryocyte cell lines. Reverse-transcription polymerase chain reaction and transient transfection of TRAIL promoter/reporter constructs were used to elucidate mechanisms of TRAIL regulation during megakaryocyte differentiation. TRAIL-dependent cytotoxicity assays were performed to determine if platelet-derived TRAIL induces apoptosis of TRAIL sensitive target cells.

RESULTS

Activated platelets expressed both membrane-bound and soluble TRAIL. TRAIL was also expressed by megakaryocytes, and in vitro studies showed that TRAIL expression was induced upon megakaryocyte differentiation. TRAIL expression was mediated by increased transcriptional activity of the TRAIL promoter, suggesting lineage-specific regulation of TRAIL during megakaryocyte differentiation. Abundant detergent-extractable, full-length TRAIL protein was observed in the lysates of platelets and megakaryocytes, but only low concentrations of TRAIL were released by nondetergent extraction methods.

CONCLUSION

The data reported herein show that platelets express TRAIL that is synthesized by megakaryocytes and was expressed by activated platelets. While these data expand the spectrum of TNF family proteins expressed in platelets, the function of platelet-derived TRAIL is not known.

TRAIL in the airways

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) is an important immunomodulatory factor that may play a role in the structural changes observed in the asthmatic airways. In vitro as well as in vivo studies have evidenced a dual role for TRAIL: it can either function as a pro- or anti-inflammatory cytokine on inflammatory cells, participating in the initiation and resolution of inflammatory and immune responses. TRAIL is expressed in the airways by inflammatory cells infiltrated in the bronchial mucosa, as well as by structural cells of the airway wall including fibroblasts, epithelial, endothelial, and smooth muscle cells. By releasing TRAIL, these different cell types may then participate in the increased levels of TRAIL observed in bronchoalveolar lavage fluid from asthmatic patients. Taken together, this suggests that TRAIL may play a role in inflammation in asthma. However, concerning its role is dual in the modulation of inflammation, further studies are needed to elucidate the precise role of TRAIL in the airways.