scholarly journals The proinflammatory cytokine tumor necrosis factor-α excites subfornical organ neurons

2017 ◽  
Vol 118 (3) ◽  
pp. 1532-1541 ◽  
Author(s):  
Nick J. Simpson ◽  
Alastair V. Ferguson
Keyword(s):  
Tumor Necrosis Factor ◽  
Proinflammatory Cytokine ◽  
Potassium Current ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Subfornical Organ ◽  
Tnf Α ◽  
Factor Α ◽  
Necrosis Factor

Tumor necrosis factor-α (TNF-α) is a proinflammatory cytokine implicated in cardiovascular and autonomic regulation via actions in the central nervous system. TNF-α−/− mice do not develop angiotensin II (ANG II)-induced hypertension, and administration of TNF-α into the bloodstream of rats increases blood pressure and sympathetic tone. Recent studies have shown that lesion of the subfornical organ (SFO) attenuates the hypertensive and autonomic effects of TNF-α, while direct administration of TNF-α into the SFO increases blood pressure, suggesting the SFO to be a key site for the actions of TNF-α. Therefore, we used patch-clamp techniques to examine both acute and long-term effects of TNF-α on the excitability of Sprague-Dawley rat SFO neurons. It was observed that acute bath application of TNF-α depolarized SFO neurons and subsequently increased action potential firing rate. Furthermore, the magnitude of depolarization and the proportion of depolarized SFO neurons were concentration dependent. Interestingly, following 24-h incubation with TNF-α, the basal firing rate of the SFO neurons was increased and the rheobase was decreased, suggesting that TNF-α elevates SFO neuron excitability. This effect was likely mediated by the transient sodium current, as TNF-α increased the magnitude of the current and lowered its threshold of activation. In contrast, TNF-α did not appear to modulate either the delayed rectifier potassium current or the transient potassium current. These data suggest that acute and long-term TNF-α exposure elevates SFO neuron activity, providing a basis for TNF-α hypertensive and sympathetic effects. NEW & NOTEWORTHY Considerable recent evidence has suggested important links between inflammation and the pathological mechanisms underlying hypertension. The present study describes cellular mechanisms through which acute and long-term exposure of tumor necrosis factor-α (TNF-α) influences the activity of subfornical organ neurons by modulating the voltage-gated transient Na+ current. This provides critical new information regarding the specific pathological mechanisms through which inflammation and TNF-α in particular may result in the development of hypertension.

scholarly journals Tumor necrosis factor-α potentiates the effects of angiotensin II on subfornical organ neurons

2018 ◽  
Vol 315 (3) ◽  
pp. R425-R433 ◽  
Author(s):  
Nick J. Simpson ◽  
Alastair V. Ferguson
Keyword(s):  
Angiotensin Ii ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Subfornical Organ ◽  
Ang Ii ◽  
Tnf Α ◽  
Intracellular Ca ◽  
Factor Α ◽  
Necrosis Factor

Inflammation is thought to play a fundamental role in the pathophysiology of hypertension and heart failure, although the mechanisms for this remain unclear. Proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), influence the subfornical organ (SFO) to modulate sympathetic activity and blood pressure. The pressor effects of TNF-α in the SFO are partially mediated by angiotensin II (ANG II) receptor type 1 (AT1R), and TNF-α is known to potentiate ANG II-induced hypertension. However, the cellular mechanism of the interaction between TNF-α and ANG II/AT1R signaling remains unknown. In the present study, we performed Ca2+ imaging on dissociated SFO neurons in vitro from male Sprague-Dawley rats to determine whether TNF-α modulates ANG II-induced increases in intracellular Ca2+ in SFO neurons. We first established that a proportion of SFO neurons respond to ANG II, an effect that required AT1R signaling and extracellular Ca2+. We then tested the hypothesis that TNF-α may modulate the effects of ANG II on SFO neurons by examining the effects of TNF-α treatment on the ANG II-induced rise in intracellular Ca2+. We discovered that TNF-α potentiated the ANG II-induced rise in intracellular Ca2+, an effect that was dependent on the duration of TNF-α treatment. Finally, we determined that this potentiation of ANG II-induced Ca2+ activity relied on tetrodotoxin-sensitive voltage-gated Na+ (vgNa+) channels. These data suggest that the potentiation of ANG II/AT1R activity by TNF-α in SFO neurons results from the previously demonstrated ability of this cytokine to modulate the activation threshold of vgNa+ currents.

#50 Gestational exposure of tumor necrosis factor-α (TNF-α) inhibitor drugs

2019 ◽  
Vol 88 ◽  
pp. 149-150 ◽  
Author(s):  
Erkoseoglu Ilknur ◽  
Kadioglu Mine ◽  
Cavusoglu Irem ◽  
Sisman Mulkiye ◽  
Aran Turhan ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Gestational Exposure ◽  
Tnf Α ◽  
Factor Α ◽  
Necrosis Factor

scholarly journals Tumor necrosis factor α Inhibition for Alzheimer’s Disease

2017 ◽  
Vol 9 ◽  
pp. 117957351770927 ◽  
Author(s):  
Rudy Chang ◽  
Kei-Lwun Yee ◽  
Rachita K Sumbria
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Short Review ◽  
Tnf Α ◽  
Factor Α ◽  
Ad Therapy ◽  
Necrosis Factor

Tumor necrosis factor α (TNF-α) plays a central role in the pathophysiology of Alzheimer’s disease (AD). Food and Drug Administration–approved biologic TNF-α inhibitors are thus a potential treatment for AD, but they do not cross the blood-brain barrier. In this short review, we discuss the involvement of TNF-α in AD, challenges associated with the development of existing biologic TNF-α inhibitors for AD, and potential therapeutic strategies for targeting TNF-α for AD therapy.

Tumor necrosis factor-α-associated lysosomal permeabilization is cathepsin B dependent

2002 ◽  
Vol 283 (4) ◽  
pp. G947-G956 ◽  
Author(s):  
Nathan W. Werneburg ◽  
M. Eugenia Guicciardi ◽  
Steven F. Bronk ◽  
Gregory J. Gores
Keyword(s):  
Tumor Necrosis Factor ◽  
Cathepsin B ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Fluorescent Protein ◽  
Tnf Α ◽  
Calcein Release ◽  
Green Fluorescent ◽  
Factor Α ◽  
Necrosis Factor

Cathepsin B (Cat B) is released from lysososomes during tumor necrosis factor-α (TNF-α) cytotoxic signaling in hepatocytes and contributes to cell death. Sphingosine has recently been implicated in lysosomal permeabilization and is increased in the liver by TNF-α. Thus the aims of this study were to examine the mechanisms involved in TNF-α-associated lysosomal permeabilization, especially the role of sphingosine. Confocal microscopy demonstrated Cat B-green fluorescent protein and LysoTracker Red were both released from lysosomes after treatment of McNtcp.24 cells with TNF-α/actinomycin D, a finding compatible with lysosomal destabilization. In contrast, endosomes labeled with Texas Red dextran remained intact, suggesting lysosomes were specifically targeted for permeabilization. LysoTracker Red was released from lysosomes in hepatocytes treated with TNF-α or sphingosine in Cat B(+/+) but not Cat B(−/−) hepatocytes, as assessed by a fluorescence-based assay. With the use of a calcein release assay in isolated lysosomes, sphingosine permeabilized liver lysosomes isolated from Cat B(+/+) but not Cat B(−/−) liver. C6ceramide did not permeabilize lysosomes. In conclusion, these data implicate a sphingosine-Cat B interaction inducing lysosomal destabilization during TNF-α cytotoxic signaling.

Tumor Necrosis Factor-α −308 Genotypes Influence Inflammatory Activity and TNF-α Serum Concentrations in Children with Juvenile Idiopathic Arthritis

2009 ◽  
Vol 36 (4) ◽  
pp. 837-842 ◽  
Author(s):  
ANA FILIPA MOURÃO ◽  
JOANA CAETANO-LOPES ◽  
PAULA COSTA ◽  
HELENA CANHÃO ◽  
MARIA JOSÉ SANTOS ◽  
...  
Keyword(s):  
Juvenile Idiopathic Arthritis ◽  
Tumor Necrosis Factor ◽  
Disease Activity ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Inflammatory Activity ◽  
Serum Concentrations ◽  
Tnf Α ◽  
Factor Α ◽  
Necrosis Factor

Objective.Considering the relevance of tumor necrosis factor-α (TNF-α) in the pathophysiology of juvenile idiopathic arthritis (JIA), it is likely that polymorphisms in its promoter area may be relevant in disease susceptibility and activity. We investigated if clinical measures of JIA activity and TNF-α serum concentrations were associated with TNF-α −308 genotypes.Methods.Portuguese patients with JIA in 5 pediatric rheumatology centers were recruited consecutively, along with a control group of healthy subjects. Demographic and clinical data and blood samples were collected from each patient. DNA was extracted for analysis of TNF-α gene promoter polymorphisms at position −308 by restriction fragment-length polymorphism.Results.One hundred fourteen patients and 117 controls were evaluated; 57% of patients presented the oligoarticular subtype, 25% the polyarticular subtype, 8% the systemic subtype, and 9% had enthesitis-related arthritis and 5% psoriatic arthritis. Twenty-four percent of the patients presented the −308 GA/AA genotypes and 76% the −308 GG genotype, similar to findings in controls. Patients with the −308 GA/AA genotype had higher degree of functional impairment, erythrocyte sedimentation rate, 100-mm visual analog scale score for disease activity, and TNF-α levels compared to those with the −308 GG genotype.Conclusion.TNF-α −308 GA/AA genotypes were found to be related to higher inflammatory activity and worse measures of disease activity in Portuguese patients with JIA. They were not associated with susceptibility to JIA.

scholarly journals Tumor Necrosis Factor α Regulates Responses to Nerve Growth Factor, Promoting Neural Cell Survival but Suppressing Differentiation of Neuroblastoma Cells

2008 ◽  
Vol 19 (3) ◽  
pp. 855-864 ◽  
Author(s):  
Yoshinori Takei ◽  
Ronald Laskey
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Neuroblastoma Cells ◽  
Erk Activation ◽  
Tnf Α ◽  
Factor Α ◽  
Necrosis Factor

Although nerve growth factor (NGF) promotes survival of neurons, tumor necrosis factor α (TNF-α) contributes to cell death triggered by NGF depletion, through TNF-α receptor (TNFR) 1. In contrast to this effect, TNF-α can promote neural cell survival via TNF-α receptor TNFR2. Although these findings demonstrate pivotal roles of TNF-α and NGF in cell fate decisions, cross-talk between these signaling pathways has not been clarified. We find that NGF can induce TNF-α synthesis through the nuclear factor-κB transcription factor. This provides a new basis for examining the cross-talk between NGF and TNF-α. Inhibition of TNFR2 shows opposite effects on two downstream kinases of NGF, extracellular signal-regulated kinase (Erk) and Akt. It increases Erk activation by NGF, and this increased activation induces differentiation of neuroblastoma cell lines. Reciprocally, inhibition of TNFR2 decreases Akt activation by NGF. Consistent with an essential role of Akt in survival signaling, inhibition of TNF-α signaling decreases NGF-dependent survival of neurons from rat dorsal root ganglia. Thus, NGF and NGF-induced TNF-α cooperate to activate Akt, promoting survival of normal neural cells. However, the NGF-induced TNF-α suppresses Erk activation by NGF, blocking NGF-induced differentiation of neuroblastoma cells. TNFR2 signaling could be a novel target to modulate cell responses to NGF.

Interleukin-1 and tumor necrosis factor-α increase insulin-like growth factor-binding protein-3 (IGFBP-3) production and IGFBP-3 protease activity in human articular chondrocytes

1995 ◽  
Vol 146 (2) ◽  
pp. 279-286 ◽  
Author(s):  
R C Olney ◽  
D M Wilson ◽  
M Mohtai ◽  
P J Fielder ◽  
R L Smith
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Articular Chondrocytes ◽  
Tnf Α ◽  
Igf I ◽  
Matrix Production ◽  
Factor Α ◽  
Necrosis Factor ◽  
Igfbp 3

Abstract IGF-I is the major anabolic factor for cartilage matrix production. Chondrocytes and cartilage treated with interleukin-1α (IL-1α), and chondrocytes from several models of inflammatory joint disease, exhibit reduced responsiveness to IGF-I. Since the IGF-binding proteins (IGFBPs) modulate the effects of IGF-I, we examined the effect of IL-1α and tumor necrosis factor-α (TNF-α) on IGFBP production by normal human articular chondrocytes in primary culture. Western ligand blots and immunoprecipitation of conditioned medium samples showed that articular chondrocytes produced IGFBPs-2, −3 and −4 and glycosylated IGFBP-4. Both IL-1α and TNF-α increased chondrocyte production of IGFBP-3, but did not alter IGFBP-4 production. The activity of a neutral metalloprotease with the ability to cleave IGFBP-3 was also increased by IL-1α. These data suggest that the cytokines IL-1α and TNF-α may act to reduce IGF-I access to chondrocytes by increasing production of IGFBP-3. This may be a factor in the decreased matrix production in the inflammatory arthritides. Journal of Endocrinology (1995) 146, 279–286

The Role of Tumor Necrosis Factor-α (TNF-α) Polymorphisms in Gastric Cancer: a Meta-Analysis

2021 ◽  
Author(s):  
Maryam Gholamalizadeh ◽  
Samaneh Mirzaei Dahka ◽  
Hadi Sedigh Ebrahim-Saraie ◽  
Mohammad Esmail Akbari ◽  
Azam Pourtaheri ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Meta Analysis ◽  
Tnf Α ◽  
Factor Α ◽  
Necrosis Factor
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