scholarly journals MIP-1α Expression Induced by Co-Stimulation of Human Monocytic Cells with Palmitate and TNF-α Involves the TLR4-IRF3 Pathway and Is Amplified by Oxidative Stress

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1799
Author(s):  
Sardar Sindhu ◽  
Nadeem Akhter ◽  
Ajit Wilson ◽  
Reeby Thomas ◽  
Hossein Arefanian ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Inflammatory Cells ◽  
H2o2 Treatment ◽  
Monocytic Cells ◽  
Metabolic Inflammation ◽  
Genetic Ablation ◽  
Protein Levels ◽  
Inflammatory Protein ◽  
Tnf Α ◽  
In Cells

Metabolic inflammation is associated with increased expression of saturated free fatty acids, proinflammatory cytokines, chemokines, and adipose oxidative stress. Macrophage inflammatory protein (MIP)-1α recruits the inflammatory cells such as monocytes, macrophages, and neutrophils in the adipose tissue; however, the mechanisms promoting the MIP-1α expression remain unclear. We hypothesized that MIP-1α co-induced by palmitate and tumor necrosis factor (TNF)-α in monocytic cells/macrophages could be further enhanced in the presence of reactive oxygen species (ROS)-mediated oxidative stress. To investigate this, THP-1 monocytic cells and primary human macrophages were co-stimulated with palmitate and TNF-α and mRNA and protein levels of MIP-1α were measured by using quantitative reverse transcription, polymerase chain reaction (qRT-PCR) and commercial enzyme-linked immunosorbent assays (ELISA), respectively. The cognate receptor of palmitate, toll-like receptor (TLR)-4, was blunted by genetic ablation, neutralization, and chemical inhibition. The involvement of TLR4-downstream pathways, interferon regulatory factor (IRF)-3 or myeloid differentiation (MyD)-88 factor, was determined using IRF3-siRNA or MyD88-deficient cells. Oxidative stress was induced in cells by hydrogen peroxide (H2O2) treatment and ROS induction was measured by dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. The data show that MIP-1α gene/protein expression was upregulated in cells co-stimulated with palmitate/TNF-α compared to those stimulated with either palmitate or TNF-α (P < 0.05). Further, TLR4-IRF3 pathway was implicated in the cooperative induction of MIP-1α in THP-1 cells, and this cooperativity between palmitate and TNF-α was clathrin-dependent and also required signaling through c-Jun and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Notably, ROS itself induced MIP-1α and could further promote MIP-1α secretion together with palmitate and TNF-α. In conclusion, palmitate and TNF-α co-induce MIP-1α in human monocytic cells via the TLR4-IRF3 pathway and signaling involving c-Jun/NF-κB. Importantly, oxidative stress leads to ROS-driven MIP-1α amplification, which may have significance for metabolic inflammation.

Brief murine myocardial I/R induces chemokines in a TNF-α-independent manner: role of oxygen radicals

2001 ◽  
Vol 281 (6) ◽  
pp. H2549-H2558 ◽  
Author(s):  
Tareck O. Nossuli ◽  
Nikolaos G. Frangogiannis ◽  
Pascal Knuefermann ◽  
Venkatesh Lakshminarayanan ◽  
Oliver Dewald ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Nuclear Factor Κb ◽  
Radical Scavenger ◽  
Reactive Oxygen Intermediate ◽  
Area At Risk ◽  
Independent Manner ◽  
Protein Levels ◽  
Inflammatory Protein ◽  
Tnf Α ◽  
Venular Endothelium

Early chemokine induction in the area at risk of an ischemic-reperfused (I/R) myocardium is first seen in the venular endothelium. Reperfusion is associated with several induction mechanisms including increased extracellular tumor necrosis factor (TNF)-α, reactive oxygen intermediate (ROI) species formation, and adhesion of leukocytes to the venular endothelium. To test the hypothesis that chemokine induction in cardiac venules can occur by ROIs in a TNF-α-independent manner, and in the absence of leukocyte accumulation, we utilized wild-type (WT) and TNF-α double-receptor knockout mice (DKO) in a closed-chest mouse model of myocardial ischemia (15 min) and reperfusion (3 h), in which there is no infarction. We demonstrate that a single brief period of I/R induces significant upregulation of the chemokines macrophage inflammatory protein (MIP) -1α, -1β, and -2 at both the mRNA and protein levels. This induction was independent of TNF-α, whereas levels of these chemokines were increased in both WT and DKO mice. Chemokine induction was seen predominantly in the endothelium of small veins and was accompanied by nuclear translocation of nuclear factor-κB and c-Jun (AP-1) in venular endothelium. Intravenous infusion of the oxygen radical scavenger N-2-mercaptopropionyl glycine (MPG) initiated 15 min before ischemia and maintained throughout reperfusion obviated chemokine induction, but MPG administration after reperfusion had begun had no effect. The results suggest that ROI generation in the reperfused myocardium rapidly induces C-C and C-X-C chemokines in the venular endothelium in the absence of infarction or irreversible cellular injury.

scholarly journals The Cooperative Induction of CCL4 in Human Monocytic Cells by TNF-α and Palmitate Requires MyD88 and Involves MAPK/NF-κB Signaling Pathways

2019 ◽  
Vol 20 (18) ◽  
pp. 4658 ◽  
Author(s):  
Sindhu ◽  
Kochumon ◽  
Shenouda ◽  
Wilson ◽  
Al-Mulla ◽  
...  
Keyword(s):  
Low Grade ◽  
Monocytic Cells ◽  
Signaling Mechanism ◽  
Blocking Antibody ◽  
Metabolic Inflammation ◽  
Qrt Pcr ◽  
Signaling Mechanisms ◽  
Tnf Α ◽  
Low Grade Inflammation ◽  
Tlr4 Receptor

: Chronic low-grade inflammation, also known as metabolic inflammation, is a hallmark of obesity and parallels with the presence of elevated circulatory levels of free fatty acids and inflammatory cytokines/chemokines. CCL4/MIP-1β chemokine plays a key role in the adipose tissue monocyte recruitment. Increased circulatory levels of TNF-α, palmitate and CCL4 are co-expressed in obesity. We asked if the TNF-α/palmitate could interact cooperatively to augment the CCL4 production in human monocytic cells and macrophages. THP-1 cells/primary macrophages were co-treated with TNF-α/palmitate and CCL4 mRNA/protein expression was assessed using qRT-PCR/ELISA. TLR4 siRNA, a TLR4 receptor-blocking antibody, XBlue™-defMyD cells and pathway inhibitors were used to decipher the signaling mechanisms. We found that TNF-α/palmitate co-stimulation augmented the CCL4 expression in monocytic cells and macrophages compared to controls (p < 0.05). TLR4 suppression or neutralization abrogated the CCL4 expression in monocytic cells. Notably, CCL4 cooperative induction in monocytic cells was: (1) Markedly less in MyD88-deficient cells, (2) IRF3 independent, (3) clathrin dependent and (4) associated with the signaling mechanism involving ERK1/2, c-Jun, JNK and NF-κB. In conclusion, TNF-α/palmitate co-stimulation promotes the CCL4 expression in human monocytic cells through the mechanism involving a TLR4-MyD88 axis and MAPK/NF-κB pathways. These findings unravel a novel mechanism of the cooperative induction of CCL4 by TNF-α and palmitate which could be relevant to metabolic inflammation.

scholarly journals Antioxidant and Anti-Inflammatory Potential of Polyphenols Contained in Mediterranean Diet in Obesity: Molecular Mechanisms

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 985 ◽  
Author(s):  
Abdelhafid Nani ◽  
Babar Murtaza ◽  
Amira Sayed Khan ◽  
Naim Akhtar Khan ◽  
Aziz Hichami
Keyword(s):  
Oxidative Stress ◽  
Mediterranean Diet ◽  
Molecular Mechanisms ◽  
Nutrition Transition ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Metabolic Inflammation ◽  
Dietary Polyphenols ◽  
Tnf Α ◽  
Anti Inflammatory ◽  
The Impact

Nutrition transition can be defined as shifts in food habits, and it is characterized by high-fat (chiefly saturated animal fat), hypercaloric and salty food consumption at the expense of dietary fibers, minerals and vitamins. Western dietary patterns serve as a model for studying the impact of nutrition transition on civilization diseases, such as obesity, which is commonly associated with oxidative stress and inflammation. In fact, reactive oxygen species (ROS) overproduction can be associated with nuclear factor-κB (NF-κB)-mediated inflammation in obesity. NF-κB regulates gene expression of several oxidant-responsive adipokines including tumor necrosis factor-α (TNF-α). Moreover, AMP-activated protein kinase (AMPK), which plays a pivotal role in energy homeostasis and in modulation of metabolic inflammation, can be downregulated by IκB kinase (IKK)-dependent TNF-α activation. On the other hand, adherence to a Mediterranean-style diet is highly encouraged because of its healthy dietary pattern, which includes antioxidant nutraceuticals such as polyphenols. Indeed, hydroxycinnamic derivatives, quercetin, resveratrol, oleuropein and hydroxytyrosol, which are well known for their antioxidant and anti-inflammatory activities, exert anti-obesity proprieties. In this review, we highlight the impact of the most common polyphenols from Mediterranean foods on molecular mechanisms that mediate obesity-related oxidative stress and inflammation. Hence, we discuss the effects of these polyphenols on a number of signaling pathways. We note that Mediterranean diet (MedDiet) dietary polyphenols can de-regulate nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) and NF-κB-mediated oxidative stress, and metabolic inflammation. MedDiet polyphenols are also effective in upregulating downstream effectors of several proteins, chiefly AMPK.

MAPKs and NF-κB differentially regulate cytokine expression in the diaphragm in response to resistive breathing: the role of oxidative stress

2011 ◽  
Vol 300 (5) ◽  
pp. R1152-R1162 ◽  
Author(s):  
Ioanna Sigala ◽  
Panayiotis Zacharatos ◽  
Dimitris Toumpanakis ◽  
Tatiana Michailidou ◽  
Olga Noussia ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cytokine Expression ◽  
Regulatory Control ◽  
Protein Levels ◽  
Cytokine Induction ◽  
Resistive Breathing ◽  
Tnf Α ◽  
The Impact ◽  
To Receive

Inspiratory resistive breathing (IRB) induces cytokine expression in the diaphragm. The mechanism of this cytokine induction remains elusive. The roles of MAPKs and NF-κB and the impact of oxidative stress in IRB-induced cytokine upregulation in the diaphragm were studied. Wistar rats were subjected to IRB (50% of maximal inspiratory pressure) via a two-way nonrebreathing valve for 1, 3, or 6 h. Additional groups of rats subjected to IRB for 6 h were randomly assigned to receive either solvent or N-acetyl-cysteine (NAC) or inhibitors of NF-κB (BAY-11–7082), ERK1/2 (PD98059), and P38 MAPK (SB203580) to study the effect of oxidative stress, NF-κB, and MAPKs in IRB-induced cytokine upregulation in the diaphragm. Quietly breathing animals served as controls. IRB upregulated cytokine (IL-6, TNF-α, IL-10, IL-2, IL-1β) protein levels in the diaphragm and resulted in increased activation of MAPKs (P38, ERK1/2) and NF-κB. Inhibition of NF-κB and ERK1/2 blunted the upregulation of all cytokines except that of IL-6, which was further increased. P38 inhibition attenuated all cytokine (including IL-6) upregulation. Both P38 and ERK1/2 inhibition decreased NF-κB/p65 subunit phosphorylation. NAC pretreatment blunted IRB-induced cytokine upregulation in the diaphragm and resulted in decreased ERK1/2, P38, and NF-κB/p65 phosphorylation. In conclusion, IRB-induced cytokine upregulation in the diaphragm is under the regulatory control of MAPKs and NF-κB. IL-6 is regulated differently from all other cytokines through a P38-dependent and NF-κB independent pathway. Oxidative stress is a stimulus for IRB-induced cytokine upregulation in the diaphragm.

scholarly journals Interferon γ induces differential upregulation of α and β chemokine secretion in colonic epithelial cell lines

Gut ◽  
1998 ◽  
Vol 42 (2) ◽  
pp. 208-213 ◽  
Author(s):  
A C Warhurst ◽  
S J Hopkins ◽  
G Warhurst
Keyword(s):  
Cell Lines ◽  
Inflammatory Cells ◽  
Interferon Γ ◽  
Inflammatory Protein ◽  
Chemotactic Protein ◽  
Tnf Α ◽  
Activated T Lymphocytes ◽  
Ifn Γ ◽  
Significant Expression ◽  
Factor Α

Background—Production of chemoattractant factors by the intestinal epithelium may contribute to mucosal infiltration by inflammatory cells in inflammatory bowel disease. Secretion of the α chemokine interleukin 8 (IL-8), a neutrophil chemoattractant, has been widely studied, but little is known about epithelial secretion of β chemokines, which are preferentially involved in recruiting monocytes.Aims—To investigate the profiles of α and β chemokine secretion in colonic cell lines and their differential modulation by interferon γ (IFN-γ), a product of activated T lymphocytes and natural killer cells.Methods and results—HT29-19A, a model of the Cl− secretory crypt cell, exhibited a parallel secretion of the α chemokines IL-8 and GROα, which could be markedly upregulated by tumour necrosis factor α (TNF-α) and IL-1β. These cells showed no significant expression of the β chemokines RANTES (regulated upon activation T cell expressed and secreted), MIP-1α (macrophage inflammatory protein 1α), and MCP-1 (monocyte chemotactic protein 1) under these conditions, but IFN-γ in combination with TNF-α caused a dose dependent induction of RANTES and MCP-1 secretion. This was accompanied by a marked increase of RANTES mRNA. In contrast, IFN-γ had no significant effect on TNF-α stimulated IL-8 secretion. Caco-2 cells, with features more typical of villus absorptive cells, were relatively poor secretors of α chemokines but secreted high levels of MCP-1 in response to IL-1β. IFN-γ did not influence α or β chemokine secretion in these cells.Conclusions—These studies suggest that intestinal epithelial cells may produce chemokines capable of attracting both neutrophils and monocytes. The ability of IFN-γ to activate the expression of β chemokines preferentially could facilitate the development of chronic inflammatory infiltrates.

Neutrophils as early immunologic effectors in hemorrhage- or endotoxemia-induced acute lung injury

2000 ◽  
Vol 279 (6) ◽  
pp. L1137-L1145 ◽  
Author(s):  
Edward Abraham ◽  
Aaron Carmody ◽  
Robert Shenkar ◽  
John Arcaroli
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Inflammatory Responses ◽  
Nuclear Factor Κb ◽  
Lung Edema ◽  
Protein Levels ◽  
Inflammatory Protein ◽  
Transcriptional Regulatory ◽  
Tnf Α ◽  
Factor Α

Acute lung injury is characterized by accumulation of neutrophils in the lungs, accompanied by the development of interstitial edema and an intense inflammatory response. To assess the role of neutrophils as early immune effectors in hemorrhage- or endotoxemia-induced lung injury, mice were made neutropenic with cyclophosphamide or anti-neutrophil antibodies. Endotoxemia- or hemorrhage-induced lung edema was significantly reduced in neutropenic animals. Activation of the transcriptional regulatory factor nuclear factor-κB after hemorrhage or endotoxemia was diminished in the lungs of neutropenic mice compared with nonneutropenic controls. Hemorrhage or endotoxemia was followed by increases in pulmonary mRNA and protein levels for interleukin-1β (IL-1β), macrophage inflammatory protein-2 (MIP-2), and tumor necrosis factor-α (TNF-α). Endotoxin-induced increases in proinflammatory cytokine expression were greater than those found after hemorrhage. The amounts of mRNA or protein for IL-1β, MIP-2, and TNF-α were significantly lower after hemorrhage in the lungs of neutropenic versus nonneutropenic mice. Neutropenia was associated with significant reductions in IL-1β and MIP-2 but not in TNF-α expression in the lungs after endotoxemia. These experiments show that neutrophils play a centrol role in initiating acute inflammatory responses and causing injury in the lungs after hemorrhage or endotoxemia.

scholarly journals Palmitate-Induced MMP-9 Expression in the Human Monocytic Cells is Mediated through the TLR4-MyD88 Dependent Mechanism

2016 ◽  
Vol 39 (3) ◽  
pp. 889-900 ◽  
Author(s):  
Sardar Sindhu ◽  
Areej Al-Roub ◽  
Merin Koshy ◽  
Reeby Thomas ◽  
Rasheed Ahmad
Keyword(s):  
Underlying Mechanism ◽  
Positive Control ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Monocytic Cells ◽  
Metabolic Inflammation ◽  
Human Monocytic Cell Line ◽  
Tnf Α ◽  
Human Monocytic Cell

Background/Aims: Obese individuals are known to have increased Matrix metalloproteinase (MMP)-9 plasma levels and MMP-9 is reported to play an important role in obesity-associated adipose tissue inflammation. Since in obesity, the levels of circulatory saturated free fatty acid (FFA) palmitate (palimitic acid) are increased and modulate the expression of inflammatory mediators, the role of palmitate in the regulation of MMP-9 remains unclear. Methods: Human monocytic cell line THP-1 and primary monocytes were stimulated with palmitate and TNF-α (positive control). MMP-9 expression was assessed with real time RT-PCR and ELISA. Signaling pathways were studied by using THP-1-XBlue™ cells, THP-1-XBlue™-defMyD cells, anti-TLR4 mAb and TLR4 siRNA. Phosphorylation of NF-kB and c-Jun was analyzed by Western blotting. Results: Here, we provide the evidence that palmitate induces MMP-9 expression at both mRNA (THP-1: 6.8 ± 1.2 Fold; P = 0.01; Primary monocytes: 5.9 ± 0.7 Fold; P = 0.0003) and protein (THP1: 1116 ±14 pg/ml; P<0.001; Primary monocytes: 1426 ± 13.8; P = 0.0005) levels in human monocytic cells. Palmitate-induced MMP-9 secretion was markedly suppressed by neutralizing anti-TLR-4 antibody (P < 0.05). Furthermore, genetic silencing of TLR4 by siRNA also significantly abrogated the palmitate-induced up-regulation of MMP-9. Additionally, MyD88-/- THP-1 cells did not express MMP-9 in response to palmitate treatment. Increased NF-κB/AP-1 activity (P<0.05) was also observed in palmitate-treated THP-1 cells. Conclusion: Altogether, these results show that palmitate induces TLR4-dependent activation of MMP-9 gene expression, which requires the recruitment of MyD88 leading to activation of NF-kB/AP-1 transcription factors. Thus, our findings suggest that the palmitate-induced MMP-9 secretion might be an underlying mechanism of its increased levels in obesity and related metabolic inflammation.

Inhibition of melanogenesis in response to oxidative stress: transient downregulation of melanocyte differentiation markers and possible involvement of microphthalmia transcription factor

2001 ◽  
Vol 114 (12) ◽  
pp. 2335-2344 ◽  
Author(s):  
Celia Jiménez-Cervantes ◽  
María Martínez-Esparza ◽  
Cristina Pérez ◽  
Nicole Daum ◽  
Francisco Solano ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Transcription Factor ◽  
Enzyme Activities ◽  
Mrna Levels ◽  
Melanin Synthesis ◽  
Differentiation Markers ◽  
H2o2 Treatment ◽  
Dopachrome Tautomerase ◽  
Protein Levels ◽  
Microphthalmia Transcription Factor

H2O2 and other reactive oxygen species are key regulators of many intracellular pathways. Within mammalian skin, H2O2 is formed as a byproduct of melanin synthesis, and following u.v. irradiation. We therefore analyzed its effects on melanin synthesis. The activity of the rate-limiting melanogenic enzyme, tyrosinase, decreased in H2O2-treated mouse and human melanoma cells. This inhibition was concentration- and time-dependent in the B16 melanoma model. Maximal inhibition (50-75%) occurred 8-16 hours after a 20 minute exposure to 0.5 mM H2O2. B16 cells withstand this treatment adequately, as shown by a small effect on glutathione levels and a rapid recovery of basal lipid peroxidation levels. Enzyme activities also recovered, beginning to increase 16-20 hours after the treatment. Inhibition of enzyme activities reflected decreased protein levels. mRNAs for tyrosinase, tyrosinase-related protein 1, dopachrome tautomerase, silver protein and melanocortin 1 receptor also decreased after H2O2 treatment, and recovered at different rates. Downregulation of melanocyte differentiation markers mRNAs was preceded by a decrease in microphthalmia transcription factor (Mitf) gene expression, which was quantitatively similar to the decrease achieved using 12-O-tetradecanoylphorbol-13-acetate. Recovery of basal Mitf mRNA levels was also observed clearly before that of tyrosinase. Therefore, oxidative stress may lead to hypopigmentation by mechanisms that include a microphthalmia-dependent downregulation of the melanogenic enzymes.

Excessive TNF-α Production Results from Reduction of c-Fos Via Aberrant Expression of Mir-34a in Neutrophils from Myelodysplastic Syndrome Patients

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1650-1650
Author(s):  
Yayoi Shikama ◽  
Meiwan Cao ◽  
Tomoyuki Ono ◽  
Michiko Anzai ◽  
Hideyoshi Noji ◽  
...  
Keyword(s):  
Mrna Stability ◽  
Aberrant Expression ◽  
Monocytic Cells ◽  
Hl60 Cells ◽  
Protein Levels ◽  
Fos Protein ◽  
Tnf Α ◽  
Inflammatory Stimuli ◽  
Group A ◽  
Group B

Abstract The molecular basis of ineffective hematopoiesis in myelodysplastic syndromes (MDS) has yet to be defined. Elevation of tumor necrosis factor (TNF)-α in bone marrow plasma has been considered to be a cause of apoptosis of hematopoietic progenitor cells, and this could result in ineffective hematopoiesis in MDS. However, the mechanism of TNF-α elevation has not been elucidated. We recently found aberrant regulation of c-fos mRNA stability in neutrophils isolated from MDS patients (Feng et al, PLoS ONE, 2013). Since the expression levels of RNA-binding proteins that regulated c-fos mRNA stability were not altered in the majority of the patients and no mutations were detected in c-fos mRNA, microRNAs were possibly involved in the insufficient stabilization of c-fos mRNA. In this study, we chose 20 microRNAs targeting c-fos according to four different databases and compared their expression levels in neutrophils between MDS patients and healthy volunteers. Among them, miR-34a and miR-155 were significantly increased in MDS (p<0.05, p<0.05). Aberrantly high expressions of miR-34a and miR-155, which were defined as greater levels than the average in the healthy cells plus 2 standard deviations, were respectively detected in 14 and 13 out of 23 patients with RCUD, RCMD, and RAEB-1. We next examined the effects of the microRNA overexpression on c-fos expression. When miR-34a and miR-155 were introduced into HL60 cells by electroporation to increase their levels to 100-fold or higher than those in the control cells, c-fos protein levels decreased to 35.0 ± 10.9% and 47.8 ± 6.8% of that in the control cells, respectively, while mRNA was not altered. In neutrophils from the patients, c-fos protein but not mRNA was significantly decreased in 13 out of 17 patients tested. The c-fos protein levels were inversely correlated with miR-34a levels (r = -0.618, p<0.05) but not with those of miR-155 (r = -0.135), suggesting that c-fos protein levels were more affected by miR-34a than miR-155. Recently, it was reported that c-fos physically interacted with nuclear factor κB (NF-κB) p65 to inhibit transcription of TNF-α in response to pro-inflammatory cytokines such as lipopolysaccharide (LPS) in monocytic cells (Koga et al, Immunity, 2009). Therefore, we hypothesized that neutrophils with reduced c-fos would overproduce TNF-α in response to inflammatory stimuli in MDS. To test our hypothesis, siRNA for c-fos was introduced into HL60 cells that were differentiated toward a neutrophil-like phenotype by 1.25% DMSO. The treatment with siRNA decreased c-fos protein levels to 58.8 ± 19.6-fold of that in the control cells. When stimulated with 1 μM LPS for 3 hours, the increase rates of TNF-α mRNA were greater in c-fos siRNA-treated cells (41.2 ± 25.7-fold, p<0.05) than in the control cells (6.1 ± 2.3-fold). Chromatin immunoprecipitation assay demonstrated that LPS increased the binding of NF-κB p65 protein to the promoter region of TNF-α DNA by 2.7 ± 1.0-fold in the control cells. In c-fos siRNA-treated cells, the amounts of NF-κB p65 bound to the TNF-α DNA promoter without stimulation were 2.1 ± 0.3-fold greater than those in the unstimulated control cells, which was further increased to 5.6±0.3-fold by stimulation with LPS (p<0.05 compared to LPS-stimulated controls). These data suggested that neutrophils, as well as monocytic cells, transcribed greater amounts of TNF-α when c-fos was decreased. Neutrophils from patients with similar c-fos levels to those in the controls (Group A, n = 5), from the patients with reduced c-fos (Group B, n = 5), and from healthy controls (n = 8) were cultured in the presence of 1 μM LPS for 3 hours. TNF-α mRNA in control neutrophils was elevated 14.9 ± 3.2-fold. The increase in Group A was 10.1 ± 4.5-fold with no significant difference from the controls, while that in Group B was greater (31.5 ± 15.1-fold, p<0.05). Although neutrophils from Group A secreted similar amounts of TNF-α into the culture medium (143.5 ± 65.7 pg/mL) to the controls (150.6 ± 91.5 pg/mL), Group B produced significantly greater amounts of TNF-α (735.4 ± 65.7 pg/mL, p<0.05 vs. controls, p<0.05 vs. Group A). Thus, our data suggest that the reduction of c-fos resulting from aberrant expression of microRNAs contributes to overproduction of TNF-α under inflammatory stimuli in MDS. Disclosures No relevant conflicts of interest to declare.

scholarly journals Novel Interplay between p53 and HO-1 in Embryonic Stem Cells

Cells ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 35
Author(s):  
Ayelén Toro ◽  
Nicolás Anselmino ◽  
Claudia Solari ◽  
Marcos Francia ◽  
Camila Oses ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stem Cells ◽  
Cellular Response ◽  
Es Cells ◽  
Embryonic Stem ◽  
Protective Role ◽  
Heme Oxygenase 1 ◽  
Mrna Levels ◽  
H2o2 Treatment ◽  
Protein Levels

Stem cells genome safeguarding requires strict oxidative stress control. Heme oxygenase-1 (HO-1) and p53 are relevant components of the cellular defense system. p53 controls cellular response to multiple types of harmful stimulus, including oxidative stress. Otherwise, besides having a protective role, HO-1 is also involved in embryo development and in embryonic stem (ES) cells differentiation. Although both proteins have been extensively studied, little is known about their relationship in stem cells. The aim of this work is to explore HO-1-p53 interplay in ES cells. We studied HO-1 expression in p53 knockout (KO) ES cells and we found that they have higher HO-1 protein levels but similar HO-1 mRNA levels than the wild type (WT) ES cell line. Furthermore, cycloheximide treatment increased HO-1 abundance in p53 KO cells suggesting that p53 modulates HO-1 protein stability. Notably, H2O2 treatment did not induce HO-1 expression in p53 KO ES cells. Finally, SOD2 protein levels are also increased while Sod2 transcripts are not in KO cells, further suggesting that the p53 null phenotype is associated with a reinforcement of the antioxidant machinery. Our results demonstrate the existence of a connection between p53 and HO-1 in ES cells, highlighting the relationship between these stress defense pathways.

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