Search

Mitoquinone (MitoQ) is a mitochondrial reactive oxygen species scavenger that is characterized by high bioavailability. Prior studies have demonstrated its neuroprotective potential. Indeed, the release of reactive oxygen species due to damage to mitochondrial components plays a pivotal role in the pathogenesis of several neurodegenerative diseases. The present study aimed to examine the impact of the inflammation platform activation on the neuronal cell line (DAOY) treated with specific inflammatory stimuli and whether MitoQ addition can modulate these deregulations. DAOY cells were pre-treated with MitoQ and then stimulated by a blockade of the cholesterol pathway, also called mevalonate pathway, using a statin, mimicking cholesterol deregulation, a common parameter present in some neurodegenerative and autoinflammatory diseases. To verify the role played by MitoQ, we examined the expression of genes involved in the inflammation mechanism and the mitochondrial activity at different time points. In this experimental design, MitoQ showed a protective effect against the blockade of the mevalonate pathway in a short period (12 h) but did not persist for a long time (24 and 48 h). The results obtained highlight the anti-inflammatory properties of MitoQ and open the question about its application as an effective adjuvant for the treatment of the autoinflammatory disease characterized by a cholesterol deregulation pathway that involves mitochondrial homeostasis.

Background: The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been involved in both physiological and pathological conditions, including vascular pathologies and pathologies of the central nervous system. Nonetheless, the knowledge about the role of systemic TRAIL in patients affected by different types of dementia and mild cognitive impairment (MCI) is still limited., Objective: We assessed serum TRAIL levels in a large cohort of older individuals (n = 644) including patients with late-onset Alzheimer's disease (LOAD), vascular dementia (VAD), 'mixed' dementia (MIX), MCI, and healthy controls., Methods: Circulating TRAIL was measured by ELISA., Results: At univariate analysis, TRAIL levels were higher in VAD, MIX, and MCI patients compared with LOAD patients and controls. Using the multiple linear regression model, we found that TRAIL levels were associated with VAD and MCI, but not MIX, independent of potential confounding factors., Conclusion: The finding of high levels of circulating TRAIL in VAD and MCI seems to suggest that both of these conditions are characterized by a significant vascular damage with respect to LOAD., (© 2016 S. Karger AG, Basel.)

The small molecule inhibitor of the MDM2/p53 interaction Nutlin-3 significantly up-regulated the steady-state mRNA and protein levels of Notch1 in TP53(wild-type) (OCI, SKW6.4) but not in TP53(deleted) (HL-60) or TP53(mutated) (BJAB) leukemic cell lines. A direct demonstration that NOTCH1 was a transcriptional target of p53 in leukemic cells was obtained in experiments carried out with siRNA for p53. Moreover, inhibition of Notch1 expression using Notch1-specific siRNA significantly increased cytotoxicity in TP53(wild-type) leukemic cells. Of note, Nutlin-3 up-regulated Notch1 expression also in primary TP53(wild-type) B-chronic lymphocytic leukemia (B-CLL) cells and the combined use of Nutlin-3 plus pharmacological gamma-secretase inhibitors of the Notch signaling showed a synergistic cytotoxicity in both TP53(wild-type) leukemic cell lines and primary B-CLL cells. A potential drawback of gamma-secretase inhibitors was their ability to enhance osteoclastic maturation of normal circulating preosteoclasts induced by RANKL + M-CSF. Notwithstanding, Nutlin-3 completely suppressed osteoclastogenesis irrespective of the presence of gamma-secretase inhibitors. Taken together, these data indicate that the p53-dependent up-regulation of Notch1 in response to Nutlin-3 represents an antiapoptotic feedback mechanism able to restrain the potential therapeutic efficacy of Nutlin-3 in hematologic malignancies. Therefore, therapeutic combinations of Nutlin-3 + gamma-secretase inhibitors might potentiate the cytotoxicity of Nutlin-3 in p53(wild-type) leukemic cells.

We have compared the cytotoxic/cytostatic responses of the SKW6.4 lymphoblastoid B-cells to the alkylating agent chlorambucil, the purine analog fludarabine, the non-genotoxic activator of the p53 pathway, Nutlin-3, used alone or in association with the death-inducing ligand recombinant TRAIL. Exposure to chlorambucil, fludarabine, and Nutlin-3 induced p53 accumulation and variably affected cell cycle progression in SKW6.4 lymphoblastoid cells. In particular, chlorambucil induced cell cycle accumulation at the G2/M checkpoint; Nutlin-3 induced early cell cycle arrest at the G1/S checkpoint, while fludarabine showed an intermediate behavior. On the other hand, recombinant TRAIL alone did not affect cell cycle progression but induced a rapid increase of apoptosis. Analysis of the gene expression profile of the p53-transcriptional targets showed distinct features between chlorambucil, Nutlin-3 and fludarabine, which likely account for their differential effect on cell cycle in SKW6.4 cells. In particular, chlorambucil upregulated the steady-state mRNA expression of SFN/14-3-3sigma, a gene involved in G2/M cell cycle arrest. Of note, all agonists upregulated TRAIL-R2 expression in SKW6.4 cells both at the mRNA and protein levels. Consistently, pretreatment with chlorambucil, fludarabine and Nutlin-3 enhanced SKW6.4 sensitivity to TRAIL-mediated apoptosis., (Copyright 2007 Wiley-Liss, Inc.)

It has been clearly established that receptor activator of nuclear factor kappa B ligand (RANKL) is a key cytokine involved in the differentiation of osteoclastic precursors of the monocytic/macrophagic lineage. However, relatively little information is available on the ability of RANKL to modulate the expression of genes controlling cell survival/apoptosis and proliferation in human osteoclastic cells in comparison to macrophages. For this purpose, CD14+ human peripheral blood mononuclear cells, which express the cognate high affinity receptor activator of nuclear factor kappa B (RANK), were differentiated along the macrophagic or osteoclastic lineage by adding macrophage-colony stimulating factor (M-CSF) or M-CSF plus RANKL in culture for 12 days. RANKL up-regulated the expression of the chemokine MIP1alpha, which potentiates osteoclastic differentiation and simultaneously activated both anti-apoptotic (Bcl-2) and pro-apoptotic (CIDEB, PYCARD, and BAK-1) genes. Moreover, RANKL markedly up-regulated cylin D2, while it significantly decreased the levels of cyclin A, cyclin-dependent kinase 2, and other cyclin-dependent kinases, in keeping with the notion that end-stage osteoclasts are nondividing cells. Finally, a long-term exposure of RANKL up-regulated the adaptor protein TRAF3 but not TRAF6., ((c) 2007 Wiley-Liss, Inc.)

Most neuroblastoma cell lines do not express apical caspases 8 and 10, which play a key role in mediating tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity in a variety of malignant cell types. In this study, we demonstrated that TRAIL induced a moderate but significant increase of apoptosis in the caspase 8/10-deficient SK-N-SH neuroblastoma cell line, through activation of a novel caspase 9/7 pathway. Concomitant to the induction of apoptosis, TRAIL also promoted a significant increase of prostaglandin E2 (PGE2) release by SK-N-SH cells. Moreover, coadministration of TRAIL plus indomethacin, a pharmacological inhibitor of cyclooxygenase (COX), showed an additive effect on SK-N-SH cell death. In spite of the ability of TRAIL to promote the phosphorylation of both ERK1/2 and p38/MAPK, which have been involved in the control of COX expression/activity, neither PD98059 nor SB203580, pharmacological inhibitors of the ERK1/2 and p38/MAPK pathways, respectively, affected either PGE2 production or apoptosis induced by TRAIL. Finally, both induction of apoptosis and PGE2 release were completely abrogated by the broad caspase inhibitor z-VAD-fmk, suggesting that both biologic end points were regulated in SK-N-SH cells through a caspase 9/7-dependent pathway.

The SK-N-MC neuroblastoma cell line, which expresses surface tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors TRAIL-R2 and TRAIL-R4, was used as a model system to examine the effect of TRAIL on key intracellular pathways involved in the control of neuronal cell survival and apoptosis. TRAIL induced distinct short-term (1-60 min) and long-term (3-24 h) effects on the protein kinase B (PKB)/Akt (Akt), extracellular signal-regulated kinase (ERK), cAMP response element-binding protein (CREB), nuclear factor kappa B (NF-kappaB) and caspase pathways. TRAIL rapidly (from 20 min) induced the phosphorylation of Akt and ERK, but not of c-Jun NH2-terminal kinase (JNK). Moreover, TRAIL increased CREB phosphorylation and phospho-CREB DNA binding activity in a phosphatidylinositol 3-kinase (PI 3K)/Akt-dependent manner. At later time points (from 3 to 6 h onwards) TRAIL induced a progressive degradation of inhibitor of kappaB (IkappaB)beta and IkappaBepsilon, but not IkappaBalpha, coupled to the nuclear translocation of NF-kappaB and an increase in its DNA binding activity. In the same time frame, TRAIL started to activate caspase-8 and caspase-3, and to induce apoptosis. Remarkably, caspase-dependent cleavage of NF-kappaB family members as well as of Akt and CREB proteins, but not of ERK, became prominent at 24 h, a time point coincident with the peak of caspase-dependent apoptosis.

In B-chronic lymphocytic leukemia (B-CLL), the interaction between leukemic cells and the microenvironment promotes tumor cell survival. The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib is one of the first-in-class molecules for the treatment of B-CLL patients; however, the emerging mechanisms of resistance to ibrutinib call for new therapeutic strategies. The purpose of the current study was to investigate the ability of ibrutinib plus the MDM2-inhibitor nutlin-3 to counteract the tumor microenvironment protective effect. We observed that primary B-CLL cells cultivated in microenvironment mimicking conditions were protected from apoptosis by the upregulation of c-MYC and of p53. In the same setting, combined treatments with ibrutinib plus nutlin-3 led to significantly higher levels of apoptosis compared to the single treatments, counteracting the c-MYC up-regulation. Moreover, the combination induced high p53 levels and a significant dissipation of the mitochondrial membrane potential, together with BAX cleavage in the more active p18 form and phospho-BAD down-regulation, that are key components of the mitochondrial apoptotic pathway, enhancing the apoptosis level. Our findings propose a new therapeutic strategy to overcome the tumor microenvironment protection involved in B-CLL resistance to drugs, with possible clinical implications also for other hematologic and solid tumors for which ibrutinib is considered a therapeutic option. [ABSTRACT FROM AUTHOR]

Background: Chronic kidney disease (CKD) patients experience a high risk of cardiovascular disease (CV); however, the factors involved in CV-related morbidity and mortality in these patients have not been fully defined. Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) is a cytokine, which exhibits pleiotropic activities on endothelial, vascular smooth muscle and inflammatory cells, with relevant effects on atheromatous plaque formation. On this basis, the present study aims to investigate the role of TRAIL in atheromatosis progression in CKD patients. Methods: Circulating TRAIL levels were measured in 378 CKD patients belonging to the Spanish National Observatory of Atherosclerosis in Nephrology (NEFRONA) study. All patients were free of previous CV events. Carotid and femoral B-mode ultrasound was performed to detect the presence of plaque at baseline and after 24 months of follow-up. Results: The lowest levels of TRAIL at baseline were significantly (p<0.05) associated with the appearance, after 24 months of follow-up, of at least two new atheromatous plaques in all territories and of one new plaque in the carotid artery, even after adjusting for CV risk factors. In addition, the patients with low levels of TRAIL at baseline were characterized by the presence of at least one hypoechoic plaque in the carotid artery. This association was significant (p<0.05) even after adjusting for CKD stage. Conclusions: Overall, the results of our study suggest TRAIL as an assertable independent prognostic biomarker for atheromatosis plaque formation in CKD patients. This observation further supports the potential role of TRAIL for the prevention/treatment of CV disease. [ABSTRACT FROM AUTHOR]

Twenty patients affected by chronic venous disease (CVD) in tertiary venous network and/or saphenous vein were analyzed before surgical ablation by echo-color-doppler for the hemodynamic parameters reflux time (RT) and resistance index (RI), a negative and a positive prognostic factor, respectively. RT and RI were next correlated with relevant in vitro parameters of venous endothelial cells (VEC) obtained from surgical specimens, such as cell migration in response to serum gradient, proliferation index, intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 expression, as well as cytokines release. Of interest, ICAM-1 expression in patient-derived VEC cultures correlated positively with RT and negatively with RI. Moreover, RT showed a positive correlation with the baseline osteoprotegerin (OPG) expression by VEC and an inverse correlation with VEC proliferation index. On the other hand, RI correlated positively with TNF-related apoptosis inducing ligand (TRAIL) expression. Among the cytokines released by VEC, GM-CSF showed a positive correlation with VEC proliferation and TRAIL expression and a negative correlation with OPG, ICAM-1 and VCAM-1 expression. Since in vitro recombinant GM-CSF induced VEC proliferation and counteracted the induction of ICAM-1,VCAM-1 and OPG upon exposure to TNF-α, our data suggest an anti-inflammatory activity of GM-CSF on venous endothelial cells. [ABSTRACT FROM AUTHOR]

Background: Since circulating levels of TNF-related apoptosis inducing ligand (TRAIL) may be important in the physiopathology of pregnancy, we tested the hypothesis that TRAIL levels change at delivery in response to stressful conditions. Methods/Principal Findings: We conducted a longitudinal study in a cohort of 73 women examined at week 12, week 16, delivery and in the corresponding cord blood (CB). Serum TRAIL was assessed in relationship with maternal characteristics and to biochemical parameters. TRAIL did not vary between 12 (67.6±27.6 pg/ml, means±SD) and 16 (64.0±16.2 pg/ml) weeks' gestation, while displaying a significant decline after partum (49.3±26.4 pg/ml). Using a cut-off decline >20 pg/ml between week 12 and delivery, the subset of women with the higher decline of circulating TRAIL (41.7%) showed the following characteristics: i) nullipara, ii) higher age, iii) operational vaginal delivery or urgent CS, iv) did not receive analgesia during labor, v) induced labor. CB TRAIL was significantly higher (131.6±52 pg/ml) with respect to the corresponding maternal TRAIL, and the variables significantly associated with the first quartile of CB TRAIL (<90 pg/ml) were higher prepregnancy BMI, induction of labor and fetal distress. With respect to the biochemical parameters, maternal TRAIL at delivery showed an inverse correlation with C-reactive protein (CRP), total cortisol, glycemia and insulin at bivariate analysis, but only with CRP at multivariate analysis. Conclusions: Stressful partum conditions and elevated CRP levels are associated with a decrease of circulating TRAIL. [ABSTRACT FROM AUTHOR]

We have analyzed the effect of the synthetic glucocorticoid dexamethasone, used alone or in combination with recombinant TRAIL, on in vitro osteoclastic differentiation of peripheral blood-derived macrophages cultured in the presence of macrophage-colony stimulating factor (M-CSF) + RANKL for 12–14 days. Dexamethasone exhibited different effects based on the concentration used. Indeed, while at 10-7 M dexamethasone reduced the number of mature osteoclasts, at 10-8 M showed no significant effects and at 10-9 M significantly increased the number of mature osteoclasts, with respect to cells cultured with only M-CSF + RANKL. On the other hand, the addition in culture of recombinant TRAIL inhibited the output of mature osteoclasts induced by M-CSF + RANKL. However, the presence of dexamethasone (10-8 or 10-9 M) into the culture medium significantly counteracted the anti-osteoclastic activity of TRAIL. In order to ascertain whether dexamethasone, might also interfere with the anti-leukemic activity of TRAIL, the degree of apoptosis induced by TRAIL was evaluated in several myeloid (OCI, MOLM, HL-60) and lymphoid (SKW6.4, MAVER, BJAB) leukemic cell lines. The levels of TRAIL-triggered apoptosis were not significantly different between leukemic cells cultured in the absence or presence of dexamethasone. Concerning the molecular mechanism mediating the dexamethasone-suppression of the TRAIL activity in pre-osteoclasts, but not in leukemic cells, we found that dexamethasone induced a significant down-regulation of the surface levels of TRAIL-R2 in cells of the osteoclastic lineage but not in leukemic cells. The ability of dexamethasone to counteract the TRAIL pathway envisions a novel mechanism mediating the pro-osteoclastic activity of dexamethasone in vivo. J. Cell. Physiol. 222: 357–364, 2010. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Experimental evidences indicate that the TNF family member TNF-related apoptosis inducing ligand (TRAIL) might be involved in modulating osteoclastic differentiation. The ability of recombinant soluble TRAIL to affect bone density in vivo was evaluated by using 4-week-old mice subcutaneously (s.c.) injected with TRAIL for 8 days. TRAIL injection induced a significant increase of tibia trabecular thickness and total bone mass in 4-week-old mice, accompanied by a significant decrease of TRAP serum levels, without modulation of osteocalcin and osteoprotegerin (OPG). Parallel experiments performed in vitro showed that inhibition of osteoclastic differentiation, induced by treatment of human peripheral blood osteoclast precursors with TRAIL, was associated to inhibition of receptor activator of nuclear factor kappa B ligand (RANKL)-induced accumulation of p27Kip1. The potential role of p27Kip1 pathway in mediating the anti-osteoclastic activity of TRAIL was further suggested by in vitro gene knock-down experiments performed in osteoclast precursor cultures. Taken together, our data strongly suggest that recombinant TRAIL inhibits osteoclastogenesis by inducing the ubiquitin-mediated degradation of p27Kip1. J. Cell. Physiol. 214:117–125, 2008. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Despite the fact that tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) and its receptors (TRAIL-Rs) are expressed in intestinal mucosa, little is known about the biological role of this system in intestinal cell physiology. The expression of surface TRAIL and TRAIL-R1, -R2, -R3, -R4 were examined by flow cytometry in the immortalized human cell line tsFHI under culture conditions promoting growth or growth arrest and expression of differentiated traits. A progressive increase of surface TRAIL expression paralleled tsFHI differentiation, consistently with immunohistochemistry analysis showing an increase of TRAIL immunostaining along the crypt–villus axis in normal jejuneal mucosa. In spite of the presence of TRAIL-R1 and TRAIL-R2 “death receptors,” recombinant TRAIL was not cytotoxic for tsFHI cells. Exposure of tsFHI to recombinant TRAIL rather increased/anticipated the expression levels of the cyclin-dependent kinase inhibitors p21 and p27, which mediate the induction of growth arrest and the stabilization of differentiated traits, respectively, as well as of the canonical differentiation marker DPPIV. The differentiation inducing activity of TRAIL was abolished by pre-incubation with a Fc-TRAIL-R2 chimera. On the other hand, TRAIL did not significantly modulate the levels of osteoprotegerin (OPG), CXCL8/IL-8, CXCL9/MIG, and CXCL10/IP10 spontaneously released or induced by inflammatory cytokines. Taken together, these data suggest that TRAIL might act as a paracrine trophic cytokine on intestinal epithelium, promoting intestinal cell differentiation. J.Cell.Physiol. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]