scholarly journals Opposing effects of tumour necrosis factor α and hyperosmolarity on Na+/myo-inositol co-transporter mRNA levels and myo-inositol accumulation by 3T3-L1 adipocytes

1998 ◽  
Vol 336 (2) ◽  
pp. 317-325 ◽  
Author(s):  
Mark A. YOREK ◽  
Joyce A. DUNLAP ◽  
William L. LOWE
Keyword(s):  
Signal Transduction ◽  
Tumour Necrosis ◽  
Actinomycin D ◽  
Signal Transduction Pathways ◽  
Mrna Levels ◽  
Tumour Necrosis Factor Α ◽  
Tnf Α ◽  
Factor Α ◽  
Opposing Effects ◽  
Necrosis Factor

Tumour necrosis factor α (TNF-α) regulates the transport of myo-inositol in 3T3-L1 adipocytes. Treating 3T3-L1 adipocytes with TNF-α decreases Na+/myo-inositol co-transporter (SMIT) mRNA levels and myo-inositol accumulation in a concentration-and time-dependent manner. TNF-α decreases the V′max for high-affinity myo-inositol transport with little change in the K′m. Studies with actinomycin D suggest that RNA synthesis is required for the TNF-α-induced effect on SMIT mRNA levels. In contrast with the effect of TNF-α, hyperosmolarity increases SMIT mRNA levels and myo-inositol accumulation in 3T3-L1 adipocytes. Hyperosmolarity increases SMIT gene expression as evidenced by the inhibition of hyperosmotic induction of SMIT mRNA levels by actinomycin D, and of myo-inositol accumulation by actinomycin D and cycloheximide. TNF-α and osmotic stress have previously been shown to activate similar signal transduction pathways in mammalian cells. In 3T3-L1 adipocytes, both TNF-α and hyperosmolarity increase mitogen-activated protein kinase kinase pathway activity; however, with the possible exception of c-Jun N-terminal kinase, this pathway does not seem to regulate SMIT mRNA levels or myo-inositol accumulation. TNF-α activates nuclear factor κB (NF-κB) in 3T3-L1 adipocytes but, unlike the effect of TNF-α on cultured endothelial cells, NF-κB does not seem to contribute to the regulation by TNF-α of SMIT gene expression in 3T3-L1 adipocytes. Therefore other signal transduction pathways must be considered in the regulation by TNF-α of SMIT mRNA levels and activity. Thus TNF-α and hyperosmolarity have opposing effects on SMIT mRNA levels and activity in 3T3-L1 adipocytes. Because myo-inositol in the form of phosphoinositides is an important component of membranes and signal transduction pathways, the regulation of myo-inositol metabolism by TNF-α might represent another mechanism by which TNF-α regulates adipocyte function.

Activated tumour necrosis factor-α shedding process is associated with in-hospital complication in patients with acute myocardial infarction

2005 ◽  
Vol 108 (4) ◽  
pp. 339-347 ◽  
Author(s):  
Yudai SHIMODA ◽  
Mamoru SATOH ◽  
Motoyuki NAKAMURA ◽  
Tomonari AKATSU ◽  
Katsuhiko HIRAMORI
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Tumour Necrosis Factor ◽  
Peripheral Blood ◽  
Tumour Necrosis ◽  
Mrna Levels ◽  
Tumour Necrosis Factor Α ◽  
Tnf Α ◽  
Factor Α ◽  
Necrosis Factor

TACE [TNF-α (tumour necrosis factor-α)-converting enzyme] plays an essential role in the shedding of TNF-α, which could affect the outcome of AMI (acute myocardial infarction). To investigate the clinical significance of the TACE–TNF-α system in AMI, we examined TACE-mediated TNF-α synthesis in PBMCs (peripheral blood mononuclear cells), which are a possible source of TNF-α in AMI. Forty-one patients with AMI and 15 healthy subjects (HS) were enrolled in the present study. PBMCs were isolated from peripheral blood on day 1 and 14 after the onset of AMI. TACE and TNF-α mRNA levels and intracellular median fluorescence intensity were measured by real-time RT (reverse transcriptase)–PCR and flow cytometry respectively. TACE-mediated TNF-α production was evaluated in cultured PBMCs with PMA, which is known to activate TACE. Spontaneous TACE and TNF-α levels were higher in AMI patients than in HS (P<0.001). TACE and TNF-α levels in PMA-stimulated PMBCs were markedly increased in AMI patients compared with HS (P<0.001). There was a positive correlation between TACE and TNF-α levels in AMI. Although spontaneous and stimulated levels of TACE and TNF-α decreased 14 days after the onset of AMI, levels in AMI patients were higher than in HS. In AMI patients with in-hospital complications (n=15; pump failure in ten, recurrent myocardial infarction in one, malignant ventricular arrhythmia in three and cardiac death in one), spontaneous and stimulated levels of TACE and TNF-α were higher than in patients without complications (P<0.01). These levels were higher in AMI patients with in-hospital complications 14 days after onset. These results demonstrate that TACE-mediated TNF-α maturation in PBMCs may play an important role in poor outcomes from AMI, suggesting that TACE may be a potential target for the inhibition of cellular TNF-α production in AMI.

Differential effect of selective block of α2-adrenoreceptors on plasma levels of tumour necrosis factor-α, interleukin-6 and corticosterone induced by bacterial lipopolysaccharide in mice

1995 ◽  
Vol 144 (3) ◽  
pp. 457-462 ◽  
Author(s):  
G Haskó ◽  
I J Elenkov ◽  
V Kvetan ◽  
E S Vizi
Keyword(s):  
Tumour Necrosis Factor ◽  
Interleukin 6 ◽  
Plasma Levels ◽  
Tumour Necrosis ◽  
Endotoxin Shock ◽  
Bacterial Lipopolysaccharide ◽  
Tumour Necrosis Factor Α ◽  
Tnf Α ◽  
Factor Α ◽  
Necrosis Factor

Abstract The effect of selective block of α2-adrenoreceptors on plasma levels of tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and corticosterone induced by bacterial lipopolysaccharide (LPS) was investigated in mice using ELISA and RIA. It was found that the LPS-induced TNF-α response was significantly blunted in mice pretreated with CH-38083, a novel and highly selective α2-adrenoreceptor antagonist (the α2/α1 ratio is >2000). In contrast, LPS-induced increases in both corticosterone and IL-6 plasma levels were further increased by CH-38083. Since it has recently been shown that the selective block of α2-adrenoreceptors located on noradrenergic axon terminals resulted in an increase in the release of noradrenaline (NA), both in the central and peripheral nervous systems, and, in our experiments, that propranolol prevented the effect of α2-adrenoreceptor blockade on TNF-α plasma levels induced by LPS, it seems likely that the excessive stimulation by NA of β-adrenoreceptors located on cytokine-secreting immune cells is responsible for this action. Since it is generally accepted that increased production of TNF-α is involved in the pathogenesis of inflammation and endotoxin shock on the one hand, and corticosterone and even IL-6 are known to possess anti-inflammatory properties on the other hand, it is suggested that the selective block of α2-adrenoreceptors might be beneficial in the treatment of inflammation and/or endotoxin shock. Journal of Endocrinology (1995) 144, 457–462

scholarly journals Intracellular NAD+ levels are associated with LPS-induced TNF-α release in pro-inflammatory macrophages

2016 ◽  
Vol 36 (1) ◽  
Author(s):  
Abbas Jawad Al-Shabany ◽  
Alan John Moody ◽  
Andrew David Foey ◽  
Richard Andrew Billington
Keyword(s):  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Inflammatory Cytokine ◽  
Bacterial Lipopolysaccharide ◽  
Tumour Necrosis Factor Α ◽  
Tnf Α ◽  
Factor Α ◽  
Inflammatory Macrophages ◽  
Inflammatory Macrophage ◽  
Necrosis Factor

Bacterial lipopolysaccharide induces changes in intracellular NAD+ levels in a pro-inflammatory, but not an anti-inflammatory, macrophage model that are correlated with the release of the pro-inflammatory cytokine tumour necrosis factor-α (TNF-α).

Cardiac Muscle Protein Gene Expression in the Endotoxin-Treated Rat

1994 ◽  
Vol 87 (5) ◽  
pp. 539-546 ◽  
Author(s):  
D. C. Macallan ◽  
G. E. Griffin
Keyword(s):  
Cardiac Muscle ◽  
Myosin Heavy Chain ◽  
Tumour Necrosis Factor ◽  
Heavy Chain ◽  
Tumour Necrosis ◽  
Muscle Protein ◽  
Mrna Levels ◽  
Tumour Necrosis Factor Α ◽  
Factor Α ◽  
Necrosis Factor

1. Sepsis is associated with marked changes in cardiac muscle protein synthesis. Such changes may be the result of altered transcription of specific myofibrillar protein mRNAs. 2. In order to investigate myofibrillar protein gene expression, a rat model of sepsis was used. Adult rats were given a single sub-lethal dose of lipopolysaccharide by the intraperitoneal route. At various times thereafter, rats were killed and ventricular muscle was removed. RNA was extracted and transferred to nylon membranes. Changes in expression of mRNA for α- and β-myosin heavy chain, α-actin, cardiac troponin C and carbonic anhydrase III were detected by Northern hybridization. 3. After treatment with lipopolysaccharide, mRNA for β-myosin heavy chain increased to 260% of control values at 24 h and reached a maximum of 310% at 48 h. α-Myosin heavy chain mRNA levels fell to 72% of control values at 24 h. mRNA levels for α-actin, cardiac troponin C and carbonic anhydrase III remained unchanged. 4. In order to investigate the role of tumour necrosis factor-α in this process, some rats were pretreated with monoclonal antibody against tumour necrosis factor-α before receiving lipopolysaccharide. Such animals showed an absence of tumour necrosis factor-α bioactivity in plasma, but changes in myocardial protein mRNA levels were no different from those seen in animals receiving lipopolysaccharide alone. 5. The reduction in protein synthesis in cardiac muscle in sepsis does not appear to be the result of reduced expression of genes for structural or soluble muscle protein. Rather there is a paradoxical increase in β-myosin heavy chain expression, which may represent a protective mechanism. Tumour necrosis factor-α does not appear to be involved in the mediation of these changes.

scholarly journals Tumour necrosis factor-α mediates blood—brain barrier damage in HIV-1 infection of the central nervous system

1992 ◽  
Vol 1 (3) ◽  
pp. 191-196 ◽  
Author(s):  
M. K. Sharief ◽  
M. Ciardi ◽  
E. J. Thompson ◽  
F. Sorice ◽  
F. Rossi ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Tumour Necrosis ◽  
Brain Barrier ◽  
Tumour Necrosis Factor Α ◽  
Blood Brain ◽  
Tnf Α ◽  
Factor Α ◽  
Hiv 1 ◽  
Blood Brain Barrier Damage ◽  
Necrosis Factor

The pathogenesis of brain inflammation and damage by human immunodeficiency virus (HIV) infection is unclear. Because blood–brain barrier damage and impaired cerebral perfusion are common features of HIV-1 infection, we evaluated the role of tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in mediating disruption of the blood–brain barrier. Levels of TNF-α were more elevated in cerebrospinal fluid (CSF) than in serum of HIV-1 infected patients and were mainly detected in those patients who had neurologic involvement. Intrathecal TNF-α levels correlated with signs of blood–brain barrier damage, manifested by high CSF to serum albumin quotient, and with the degree of barrier impairment. In contrast, intrathecal IL-1β levels did not correlate with blood-brain barrier damage in HIV-1 infected patients. TNF-α seems to be related to active neural inflammation and to blood–brain barrier damage. The proinflammatory effects of TNF-α in the nervous system are dissociated from those of IL-1β.

Effects of tumor necrosis factor α on leptin-sensitive intestinal vagal mechanoreceptors in the cat

2013 ◽  
Vol 91 (11) ◽  
pp. 941-950 ◽  
Author(s):  
Nathalie Quinson ◽  
Véronique Vitton ◽  
Michel Bouvier ◽  
Jean-Charles Grimaud ◽  
Anne Abysique
Keyword(s):  
Tumour Necrosis ◽  
Discharge Frequency ◽  
Tumour Necrosis Factor Α ◽  
Tnf Α ◽  
Inflammatory Bowel ◽  
Pre Treatment ◽  
Factor Α ◽  
Necrosis Factor

The involvement of tumour necrosis factor α (TNF-α) in inflammatory bowel disease (IBD) has been established, and anti-TNF-α has been suggested as a therapeutic approach for the treatment of these pathologies. We studied the effects of TNF-α on leptin-sensitive intestinal vagal units to determine whether TNF-α exerts its effects through the intestinal vagal mechanoreceptors and to investigate its interactions with substances regulating food intake. The activity of intestinal vagal mechanoreceptors was recorded via microelectrodes implanted into the nodose ganglion in anesthetized cats. TNF-α (1 μg, i.a.) increased the discharge frequency of leptin-activated units (type 1 units; P < 0.05) and had no effect on the discharge frequency of leptin-inhibited units (type 2 units). When TNF-α was administered 20 min after sulfated cholecystokinin-8 (CCK), its excitatory effects on type 1 units were significantly enhanced (P < 0.0001) and type 2 units were significantly (P < 0.05) activated. Pre-treatment with Il-1ra (250 μg, i.a.) blocked the excitatory effects of TNF-α on type 1 units whereas the excitatory effects of TNF-α administration after CCK treatment on type 2 units were not modified. The activation of leptin-sensitive units by TNF-α may explain, at least in part, the weight loss observed in IBD.

Sign in / Sign up

Export Citation Format

Share Document