scholarly journals Tumor Necrosis Factor-alpha utilizes MAPK/NFκB pathways to induce cholesterol-25 hydroxylase for amplifying pro-inflammatory response via 25-hydroxycholesterol-integrin-FAK pathway

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257576
Author(s):  
Swechha M. Pokharel ◽  
Kim Chiok ◽  
Niraj K. Shil ◽  
Indira Mohanty ◽  
Santanu Bose
Keyword(s):  
Transcription Factor ◽  
Tumor Necrosis Factor ◽  
Inflammatory Response ◽  
Cell Surface ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Wide Spectrum ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Necrosis Factor

Exaggerated inflammatory response results in pathogenesis of various inflammatory diseases. Tumor Necrosis Factor-alpha (TNF) is a multi-functional pro-inflammatory cytokine regulating a wide spectrum of physiological, biological, and cellular processes. TNF induces Focal Adhesion Kinase (FAK) for various activities including induction of pro-inflammatory response. The mechanism of FAK activation by TNF is unknown and the involvement of cell surface integrins in modulating TNF response has not been determined. In the current study, we have identified an oxysterol 25-hydroxycholesterol (25HC) as a soluble extracellular lipid amplifying TNF mediated innate immune pro-inflammatory response. Our results demonstrated that 25HC-integrin-FAK pathway amplifies and optimizes TNF-mediated pro-inflammatory response. 25HC generating enzyme cholesterol 25-hydroxylase (C25H) was induced by TNF via NFκB and MAPK pathways. Specifically, chromatin immunoprecipitation assay identified binding of AP-1 (Activator Protein-1) transcription factor ATF2 (Activating Transcription Factor 2) to the C25H promoter following TNF stimulation. Furthermore, loss of C25H, FAK and α5 integrin expression and inhibition of FAK and α5β1 integrin with inhibitor and blocking antibody, respectively, led to diminished TNF-mediated pro-inflammatory response. Thus, our studies show extracellular 25HC linking TNF pathway with integrin-FAK signaling for optimal pro-inflammatory activity and MAPK/NFκB-C25H-25HC-integrin-FAK signaling network playing an essential role to amplify TNF dependent pro-inflammatory response. Thus, we have identified 25HC as the key factor involved in FAK activation during TNF mediated response and further demonstrated a role of cell surface integrins in positively regulating TNF dependent pro-inflammatory response.

scholarly journals Shiga Toxin 1-Induced Inflammatory Response in Lipopolysaccharide-Sensitized Astrocytes Is Mediated by Endogenous Tumor Necrosis Factor Alpha

2009 ◽  
Vol 78 (3) ◽  
pp. 1193-1201 ◽  
Author(s):  
Verónica I. Landoni ◽  
Marcelo de Campos-Nebel ◽  
Pablo Schierloh ◽  
Cecilia Calatayud ◽  
Gabriela C. Fernandez ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Inflammatory Response ◽  
Tumor Necrosis Factor Alpha ◽  
Shiga Toxin ◽  
Tumor Necrosis ◽  
Brain Inflammation ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Factor Alpha ◽  
Necrosis Factor

ABSTRACT Hemolytic-uremic syndrome (HUS) is generally caused by Shiga toxin (Stx)-producing Escherichia coli. Endothelial dysfunction mediated by Stx is a central aspect in HUS development. However, inflammatory mediators such as bacterial lipopolysaccharide (LPS) and polymorphonuclear neutrophils (PMN) contribute to HUS pathophysiology by potentiating Stx effects. Acute renal failure is the main feature of HUS, but in severe cases, patients can develop neurological complications, which are usually associated with death. Although the mechanisms of neurological damage remain uncertain, alterations of the blood-brain barrier associated with brain endothelial injury is clear. Astrocytes (ASTs) are the most abundant inflammatory cells of the brain that modulate the normal function of brain endothelium and neurons. The aim of this study was to evaluate the effects of Stx type 1 (Stx1) alone or in combination with LPS in ASTs. Although Stx1 induced a weak inflammatory response, pretreatment with LPS sensitized ASTs to Stx1-mediated effects. Moreover, LPS increased the level of expression of the Stx receptor and its internalization. An early inflammatory response, characterized by the release of tumor necrosis factor alpha (TNF-α) and nitric oxide and PMN-chemoattractant activity, was induced by Stx1 in LPS-sensitized ASTs, whereas activation, evidenced by higher levels of glial fibrillary acid protein and cell death, was induced later. Furthermore, increased adhesion and PMN-mediated cytotoxicity were observed after Stx1 treatment in LPS-sensitized ASTs. These effects were dependent on NF-κB activation or AST-derived TNF-α. Our results suggest that TNF-α is a pivotal effector molecule that amplifies Stx1 effects on LPS-sensitized ASTs, contributing to brain inflammation and leading to endothelial and neuronal injury.

scholarly journals Moderate Dose of Lipopolysaccharide Induces Tumor Necrosis Factor-alpha and Interleukin-6 Production by Human Monocyte-derived Macrophages

2021 ◽  
Vol 9 (A) ◽  
pp. 468-472
Author(s):  
Nuraiza Meutia ◽  
Lokot Donna Lubis ◽  
Eka Roina Megawati
Keyword(s):  
Tumor Necrosis Factor ◽  
Inflammatory Response ◽  
Tumor Necrosis Factor Alpha ◽  
Interleukin 6 ◽  
Tumor Necrosis ◽  
Human Monocyte ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Factor Alpha ◽  
Necrosis Factor

BACKGROUND: Macrophages have been widely used for in vitro studies. Despite different types and doses of stimulatory agents that have been tested, there is no consensus for the method. AIM: This study was aimed to determine a sufficient dose of lipopolysaccharide (LPS) to stimulate inflammatory response in macrophages. METHODS: Whole blood was collected from four donors after written informed consent. The monocytes were isolated from peripheral blood mononuclear cells and stimulated with macrophage colony-stimulating factor, LPS, and Interferon-gamma for 6 days until differentiated into macrophages. The production of Tumor necrosis factor-alpha (TNF-α) and Interleukin-6 (IL-6) were quantified after 24-h further stimulation with 100 ng/mL and 2 μg/mL of LPS. RESULTS: Both doses increased TNF-α _production compare to their controls, but not statistically different (p > 0.05). There were also no differences in IL-6 production between treatments, 56.55 ± 32.30 pg/mL and 70.96 ± 65.08 pg/mL, respectively. CONCLUSION: A dose of 100 ng/mL of LPS was sufficient to stimulate inflammatory response in human monocyte-derived macrophages. A 24-h duration of macrophage stimulation was sufficient to observed the production TNF-α.

scholarly journals Features of cytokine profile in patients with local and generalized soft tissue infections

2013 ◽  
Vol 94 (4) ◽  
pp. 455-459
Author(s):  
N A Barkhatova
Keyword(s):  
Tumor Necrosis Factor ◽  
Inflammatory Response ◽  
Receptor Antagonist ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Interleukin 1 ◽  
Necrosis Factor Alpha ◽  
Interleukin 1 Receptor Antagonist ◽  
Factor Alpha ◽  
Necrosis Factor

Aim. To determine the features of cytokine profile in patients with local and generalized soft tissue infections. Methods. The treatment results of 2350 patients with soft tissues infections since 1998 to 2012 were analyzed. ELISA test was used to measure tumor necrosis factor alpha and interleukin-1 receptor antagonist levels in 300 randomly picked patients with local (75 patients, comparison group) and generalized (225 patients, main group) forms of soft tissue infections. Results. In patients with generalized infections, tumor necrosis factor alpha level was 1.5 times higher in patients with mild systemic inflammatory response, 3.5 times higher - in patients with moderate and 6.7 times higher in patients with severe systemic inflammatory response compared to healthy controls. Interleukin-1 receptor antagonist levels were also elevated and related to the degree of inflammatory response, thus, it was the highest (2 times higher compared to controls) in patients with moderate systemic inflammatory response, while in patients with mild and severe inflammation it was only 30-40% higher. The significant increase in tumor necrosis factor alpha level associated with normal interleukin-1 receptor antagonist level is characteristic for different forms of sepsis. At the same time, increase in interleukin-1 receptor antagonist level associated with minimal changes in tumor necrosis factor alpha level can be used as a diagnostic criteria for compensated inflammatory response I patients with local infections cytokine profile was normal. The severity of systemic inflammation and clinical course of generalized infection depended not only on the absolute increase of cytokine levels, but on pro-inflammatory (tumor necrosis factor alpha) and anti-inflammatory (interleukin-1 receptor antagonist) cytokine levels misbalance. Conclusion. Examining the serum cytokine levels allows to confirm the diagnosis of generalized infection on early stages and to differentiate between compensated and non-ompensated systemic inflammatory response.

scholarly journals Macrophage-Elicited Osteoclastogenesis in Response to Bacterial Stimulation Requires Toll-Like Receptor 2-Dependent Tumor Necrosis Factor-Alpha Production

2007 ◽  
Vol 76 (2) ◽  
pp. 812-819 ◽  
Author(s):  
Takashi Ukai ◽  
Hiromichi Yumoto ◽  
Frank C. Gibson ◽  
Caroline Attardo Genco
Keyword(s):  
Tumor Necrosis Factor ◽  
Cell Surface ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Toll Like Receptor ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Toll Like Receptor 2 ◽  
Factor Alpha ◽  
Necrosis Factor

ABSTRACT The receptor activator of NF-κB ligand (RANKL) and the proinflammatory cytokines are believed to play important roles in osteoclastogenesis. We recently reported that the innate immune recognition receptor, Toll-like receptor 2 (TLR2), is crucial for inflammatory bone loss in response to infection by Porphyromonas gingivalis, the primary organism associated with chronic inflammatory periodontal disease. However, the contribution of macrophage-expressed TLRs to osteoclastogenesis has not been defined. In this study, we defined a requirement for TLR2 in tumor necrosis factor-alpha (TNF-α)-elicited osteoclastogenesis in response to exposure to P. gingivalis. Culture supernatant (CS) fluids from P. gingivalis-stimulated macrophages induced bone marrow macrophage-derived osteoclastogenesis. This activity was dependent on TNF-α and occurred independently of RANKL, interleukin-1β (IL-1β), and IL-6. CS fluids from P. gingivalis-stimulated TLR2−/− macrophages failed to express TNF-α, and these fluids induced significantly less osteoclast formation compared with that of the wild-type or the TLR4−/− macrophages. In addition, P. gingivalis exposure induced up-regulation of TLR2 expression on the cell surface of macrophages, which was demonstrated to functionally react to reexposure to P. gingivalis, as measured by a further increase in TNF-α production. These results demonstrate that macrophage-dependent TLR2 signaling is crucial for TNF-α-dependent/RANKL-independent osteoclastogenesis in response to P. gingivalis infection. Furthermore, the ability of P. gingivalis to induce the cell surface expression of TLR2 may contribute to the chronic inflammatory state induced by this pathogen.

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