Cytokine-induced metabolic effects in human adipocytes are independent of endogenous nitric oxide

2006 ◽  
Vol 290 (6) ◽  
pp. E1068-E1077 ◽  
Author(s):  
Philippe Linscheid ◽  
Dalma Seboek ◽  
Henryk Zulewski ◽  
Arnaud Scherberich ◽  
Nenad Blau ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Adipose Tissue ◽  
Metabolic Regulation ◽  
Oxidation Products ◽  
No Oxidation ◽  
Metabolic Effects ◽  
Inos Mrna ◽  
Peroxisome Proliferator ◽  
Human Adipocytes ◽  
Nos Inhibitors

Nitric oxide (NO) has been recognized as a potential mediator of inflammation-induced metabolic alterations, including insulin resistance. However, expression mechanisms and potential roles of endothelial and inducible NO synthases (eNOS and iNOS, respectively) in human adipocytes are poorly understood. In the present study, we aimed to analyze several aspects of NO-related gene expression and metabolite synthesis in basal and inflammation-activated human adipocyte models. eNOS mRNA was highly expressed in omental and to a lesser extent in human subcutaneous adipose tissue biopsies, but not in purified adipocytes, in mesenchymal stem cell (MSC)- and in preadipocyte-derived adipocytes, respectively. Trace amounts of iNOS mRNA were detected in adipose tissue samples of donors with abdominal infection, as opposed to noninfected subjects. Interferon-γ, in combination with interleukin-1β or lipopolysaccharide, evoked a transient (4 h < time < 24 h) iNOS mRNA expression in human MSC and preadipocyte-derived adipocytes, respectively. This induction was preceded by cytokine-specific mRNAs. In addition, it was accompanied by an activation of the tetrahydrobiopterin synthesis pathway and by inhibition of peroxisome proliferator-activated receptor-γ2. In contrast to murine 3T3-L1-derived adipocytes, iNOS protein and NO oxidation products remained undetectable in iNOS mRNA-positive human adipocytes. Accordingly, coadministration of NOS inhibitors (i.e., Nω-nitro-l-arginine methyl ester, Nω-monomethyl-l-arginine, and 1400W) had no effects on insulin-mediated glucose uptake and lipolysis. We conclude that, in human adipocytes, endogenous NO is not involved in metabolic regulation during either basal or cytokine-activated conditions.

Acute effect of insulin on nitric oxide synthesis in humans: a precursor-product isotopic study

2007 ◽  
Vol 293 (3) ◽  
pp. E776-E782 ◽  
Author(s):  
Paolo Tessari ◽  
Anna Coracina ◽  
Lucia Puricelli ◽  
Monica Vettore ◽  
Alessandra Cosma ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Acute Effect ◽  
Oxidation Products ◽  
No Oxidation ◽  
Metabolic Effects ◽  
Whole Body ◽  
Fasting State ◽  
Isotopic Study ◽  
Euglycemic Hyperinsulinemic Clamp

Nitric oxide (NO) is a key regulatory molecule with wide vascular, cellular, and metabolic effects. Insulin affects NO synthesis in vitro. No data exist on the acute effect of insulin on NO kinetics in vivo. By employing a precursor-product tracer method in humans, we have directly estimated the acute effect of insulin on intravascular NOx (i.e., the NO oxidation products) fractional (FSR) and absolute (ASR) synthesis rates in vivo. Nine healthy male volunteers were infused iv with l-[15N2-guanidino]arginine ([15N2]arginine) for 6 h. Timed measurements of 15NOx and [15N2]arginine enrichments in whole blood were performed in the first 3 h in the fasting state and then following a 3-h euglycemic-hyperinsulinemic clamp (with plasma insulin raised to ≈1,000 pmol/l). In the last 60 min of each experimental period, at ≈steady-state arginine enrichment, a linear increase of 15NOx enrichment (mean r = 0.9) was detected in both experimental periods. In the fasting state, NOx FSR was 27.4 ± 4.3%/day, whereas ASR was 0.97 ± 0.36 mmol/day, accounting for 0.69 ± 0.27% of arginine flux. Following hyperinsulinemia, both FSR and ASR of NOx increased (FSR by ≈50%, to 42.4 ± 6.7%/day, P < 0.005; ASR by ≈25%, to 1.22 ± 0.41 mmol/day, P = 0.002), despite a ≈20–30% decrease of arginine flux and concentration. The fraction of arginine flux used for NOx synthesis was doubled, to 1.13 ± 0.35% ( P < 0.003). In conclusion, whole body NOx synthesis can be directly measured over a short observation time with stable isotope methods in humans. Insulin acutely stimulates NOx synthesis from arginine.

Hypoxia inhibits nitric oxide synthesis in isolated rabbit lung

1997 ◽  
Vol 272 (6) ◽  
pp. L1167-L1173 ◽  
Author(s):  
S. P. Kantrow ◽  
Y. C. Huang ◽  
A. R. Whorton ◽  
E. N. Grayck ◽  
J. M. Knight ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Competitive Inhibitor ◽  
Oxidation Products ◽  
No Oxidation ◽  
Severe Hypoxia ◽  
No Production ◽  
Rabbit Lung ◽  
Vasoconstrictor Response ◽  
Hypoxic Vasoconstriction ◽  
Oxide Synthase

Nitric oxide (NO.) has been proposed to modulate hypoxic vasoconstriction in the lung. The activity of nitric oxide synthase (NOS) can be inhibited by hypoxia because molecular oxygen is a necessary substrate for the enzyme. On the basis of this mechanism, we hypothesized that NOS activity has a key role in regulation of pulmonary vascular tone during hypoxia. We measured oxidation products of NO. released into the vasculature of isolated buffer-perfused rabbit lung ventilated with normoxic (21% O2), moderately hypoxic (5% O2), or anoxic (0% O2) gas using two methods. Mean PO2 in perfusate exiting the lung was 25 Torr during anoxic ventilation and 47 Torr during moderately hypoxic ventilation. We found that the amount of the NO. oxidation product nitrite released into the perfusate was suppressed significantly during ventilation with anoxic but not moderately hypoxic gas. During normoxic ventilation, nitrite release was inhibited by pretreatment with NG-monomethyl-L-arginine, a competitive inhibitor of NOS. To confirm that changes in nitrite concentration reflected changes in NO. release into the perfusate, major oxidation products of NO. (NOx) were assayed using a method for reduction of these products to NO. by vanadium(III) Cl. Release of NOx into the perfusate was suppressed by severe hypoxia (anoxic ventilation), and this effect was reversed by normoxia. Pulmonary vasoconstriction was observed during severe but not moderate hypoxia and was related inversely to the rate of nitrite release. These observations provide evidence that decreased NO. production contributes to the pulmonary vasoconstrictor response during severe hypoxia.

scholarly journals Basal and stimulated nitric oxide in control of kidney function in the aging rat

1997 ◽  
Vol 272 (6) ◽  
pp. R1747-R1753 ◽  
Author(s):  
C. Hill ◽  
A. M. Lateef ◽  
K. Engels ◽  
L. Samsell ◽  
C. Baylis
Keyword(s):  
Nitric Oxide ◽  
Vascular Resistance ◽  
Pressor Response ◽  
Renal Vascular Resistance ◽  
Oxidation Products ◽  
No Oxidation ◽  
No Production ◽  
Sprague Dawley ◽  
Vasoconstrictor Response ◽  
Renal Vascular

To investigate the activity of nitric oxide (NO) in control of renal hemodynamics during aging, studies were conducted on conscious Sprague-Dawley rats aged 3-5 mo (young, Y) and 18-22 mo (old, O). Blood pressure (BP) and renal vascular resistance (RVR) were higher in O vs. Y in control, and acute systemic NO synthesis inhibition (NOSI) increased BP and RVR, with an enhanced renal vasoconstrictor response in O. Infusion of the NO substrate L-arginine produced similar, selective renal vasodilation in both groups. The endothelium-dependent vasodilator acetylcholine caused similar falls in BP and RVR, whereas sodium nitroprusside produced an exaggerated depressor response in O vs. Y without falls in RVR in either age group. Urinary excretion of the stable NO oxidation products (NOx) decreased with age, suggesting a decline in the overall somatic NO production. In conclusion, basal tonically produced NO has a more pronounced role in maintenance of renal perfusion in aging, whereas L-arginine- and agonist-stimulated renal vasodilation is not impaired with age. NO production from some source may be reduced with aging, as indicated by falls in 24-h NOX excretion, although the similarity in pressor response and enhanced renal vasoconstrictor response to NOSI suggests that the role of NO in control of total peripheral and renal vascular resistance is maintained.

B-Cell Chronic Lymphocytic Leukemia Cells Express a Functional Inducible Nitric Oxide Synthase Displaying Anti-Apoptotic Activity

Blood ◽  
1998 ◽  
Vol 92 (3) ◽  
pp. 1031-1043 ◽  
Author(s):  
Haixia Zhao ◽  
Nathalie Dugas ◽  
Claire Mathiot ◽  
Alain Delmer ◽  
Bernard Dugas ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Chronic Lymphocytic Leukemia ◽  
Nitric Oxide Synthase ◽  
B Cell ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Inos Mrna ◽  
Nos Inhibitors ◽  
Oxide Synthase ◽  
Cell Chronic Lymphocytic Leukemia

The expression of different isoforms of nitric oxide synthase (NOS) was investigated in B-cell chronic lymphocytic leukemia (B-CLL) to delineate a possible role for nitric oxide (NO) in the control of apoptosis of the tumoral cells. By reverse transcription-polymerase chain reaction (RT-PCR), all B-CLL cells were found to express spontaneously inducible NOS (iNOS) mRNA, whereas endothelial constitutive NOS (ecNOS) mRNA was undetectable. The iNOS protein was detected by immunofluorescence in the cytoplasm of permeabilized leukemic cells and identified by Western blotting, using different anti-iNOS antibodies, as a protein of 135 kD in B-CLL cytoplasmic extracts. B-CLL cell lysates also displayed basal NOS enzymatic activity, as measured by the conversion of14C-labeled L-arginine into 14C-L-citrulline. Ligation of CD23, expressed on the vast majority of B-CLL cells, resulted in increased iNOS expression and activity. The NO released exerted an anti-apoptotic effect on B-CLL cells that was counteracted by NOS inhibitors and engagement of the APO-1/Fas pathway. Therefore, the existence of a functional iNOS in B-CLL cells will provide further insights into the mechanisms that control proliferation and apoptosis in these tumor cells. © 1998 by The American Society of Hematology.

Enhanced gene expression of endothelial nitric oxide synthase in brown adipose tissue during cold exposure

2002 ◽  
Vol 282 (2) ◽  
pp. R623-R626 ◽  
Author(s):  
Kazue Kikuchi-Utsumi ◽  
Bihu Gao ◽  
Hiroshi Ohinata ◽  
Masaaki Hashimoto ◽  
Noriyuki Yamamoto ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cold Exposure ◽  
Inos Mrna ◽  
No Production ◽  
Mrna Levels ◽  
Cold Stimulation ◽  
Brown Adipose ◽  
Enos Mrna

It has been shown that norepinephrine (NE) can mediate vasodilatation by stimulating the production of nitric oxide (NO) in brown adipose tissue (BAT), resulting in an increase in BAT blood flow. We speculated that constitutive NO synthase (NOS) is involved in this NO production. However, it is not known whether constitutive NOS is expressed in BAT. To answer this question, we assessed the expression of two types of constitutive NOS, endothelial (eNOS) and neuronal NOS (nNOS), in BAT of rats. eNOS was abundantly expressed in both BAT and isolated brown adipocytes, whereas nNOS was not. Cold exposure, which is known to stimulate NE release from sympathetic nerve terminals in BAT, led to a significant increase in eNOS mRNA in this tissue. In contrast, very low levels of inducible NOS (iNOS) mRNA were expressed, and cold stimulation failed to increase iNOS mRNA levels in BAT. These results suggest that eNOS is the primary isoform that is responsible for NO production in BAT and that its expression may be under sympathetic control.

TWEAK prevents TNF-α-induced insulin resistance through PP2A activation in human adipocytes

2013 ◽  
Vol 305 (1) ◽  
pp. E101-E112 ◽  
Author(s):  
Ana Vázquez-Carballo ◽  
Victòria Ceperuelo-Mallafré ◽  
Matilde R. Chacón ◽  
Elsa Maymó-Masip ◽  
Margarita Lorenzo ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Insulin Signaling ◽  
Visceral Fat ◽  
Molecular Mechanisms ◽  
Physiological Role ◽  
Metabolic Effects ◽  
Human Adipocytes ◽  
Fat Depots ◽  
Tnf Α

Visceral fat is strongly associated with insulin resistance. Obesity-associated adipose tissue inflammation and inflammatory cytokine production are considered key mediators of insulin signaling inhibition. TWEAK is a relatively new member of the TNF cytokine superfamily, which can exist as full length membrane-associated (mTWEAK) and soluble (sTWEAK) isoforms. Although TWEAK has been shown to have important functions in chronic inflammatory diseases its physiological role in adipose tissue remains unresolved. In this study, we explore the molecular mechanisms involved in the modulation of TNF-α-induced effects on insulin sensitivity by sTWEAK in a human visceral adipose cell line and also in primary human adipocytes obtained from visceral fat depots. Our data reveal that sTWEAK ameliorates TNF-α-induced insulin resistance on glucose uptake, GLUT4 translocation and insulin signaling without affecting other metabolic effects of TNF-α such as lipolysis or apoptotis. Co-immunoprecipitation experiments in adipose cells revealed that pretreatment with sTWEAK specifically inhibits TRAF2 association with TNFR1, but not with TNFR2, which mediates insulin resistance. However, sTWEAK does not affect other downstream molecules activated by TNF-α, such as TAK1. Rather, sTWEAK abolishes the stimulatory effect of TNF-α on JNK1/2, which is directly involved in the development of insulin resistance. This is associated with an increase in PP2A activity upon sTWEAK treatment. Silencing of the PP2A catalytic subunit gene overcomes the dephosphorylation effect of sTWEAK on JNK1/2, pointing to PP2A as a relevant mediator of sTWEAK-induced JNK inactivation. Overall, our data reveal a protective role of TWEAK in glucose homeostasis and identify PP2A as a new driver in the modulation of TNF-α signaling by sTWEAK.

Pulmonary alveolar epithelial inducible NO synthase gene expression: regulation by inflammatory mediators

1995 ◽  
Vol 268 (3) ◽  
pp. L501-L508 ◽  
Author(s):  
H. H. Gutierrez ◽  
B. R. Pitt ◽  
M. Schwarz ◽  
S. C. Watkins ◽  
C. Lowenstein ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Gene Expression Regulation ◽  
Interleukin 1 ◽  
Alveolar Epithelium ◽  
Cell Types ◽  
Oxidation Products ◽  
No Oxidation ◽  
Target Cells ◽  
Cell Permeabilization ◽  
Necrosis Factor Alpha

Nitric oxide (.NO) is a short-lived mediator that can be induced by different cytokines and lipopolysaccharide (LPS) in a variety of cell types and produces many physiological and metabolic changes in target cells. In the current study, we show that a combination of cytokines, LPS, and zymosan-activated serum (ZAS; called for convenience cytomix Z) induces production of high concentrations of the NO oxidation products nitrite (NO2-) and nitrate (NO3-) by cultured rat fetal lung epithelial type II cells in a time-dependent fashion. Interferon-gamma and tumor necrosis factor-alpha alone did not significantly affect .NO synthesis, whereas ZAS, LPS, and interleukin-1 beta caused only a modest increase in formation of .NO oxidation products. Production of NO2- and NO3- was inhibited by NG-monomethyl-L-arginine and cyclohexmide. After exposure of these cells to a combination of the above cytokines, Escherichia coli LPS, and ZAS (cytomix Z), enhanced inducible nitric oxide synthase (iNOS) expression was indicated by an elevation in steady-state mRNA specific for iNOS (via Northern blot analysis) and increased immunofluorescence for iNOS after cell permeabilization, incubation with anti-iNOS antibody, and treatment with Cy3.18-conjugated rabbit-specific antibody. The extent of inflammatory mediator-induced.NO production by alveolar epithelium, which exceeds that of other lung cell types, reveals new insight into mechanisms of pulmonary host defense and pathways of free radical-mediated lung injury.

Hesperidin protects against cyclophosphamide-induced hepatotoxicity by upregulation of PPARγ and abrogation of oxidative stress and inflammation

2014 ◽  
Vol 92 (9) ◽  
pp. 717-724 ◽  
Author(s):  
Ayman M. Mahmoud
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Protective Effect ◽  
Liver Lipid ◽  
Inos Mrna ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Protective Effects ◽  
Peroxisome Proliferator Activated Receptor ◽  
Intraperitoneal Dose

The most important reason for the non-approval and withdrawal of drugs by the Food and Drug Administration is hepatotoxicity. Therefore, this study was undertaken to evaluate the protective effects of hesperidin against cyclophosphamide (CYP)-induced hepatotoxicity in Wistar rats. The rats received a single intraperitoneal dose of CYP of 200 mg/kg body mass, followed by treatment with hesperidin, orally, at doses of 25 and 50 mg/kg for 11 consecutive days. CYP induced hepatic damage, as evidenced by the significantly elevated levels of serum pro-inflammatory cytokines, serum transaminases, liver lipid peroxidation, and nitric oxide. As a consequence, there was reduced glutathione content, and the activities of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase, were markedly reduced. In addition, CYP administration induced a considerable downregulation of peroxisome proliferator activated receptor gamma (PPARγ) and upregulation of nuclear factor-kappa B (NF-κB) and inducible nitric oxide synthase (iNOS) mRNA expression. Hesperidin, in a dose-dependent manner, rejuvenated the altered markers to an almost normal state. In conclusion, hesperidin showed a potent protective effect against CYP-induced oxidative stress and inflammation leading to hepatotoxicity. The study suggests that hesperidin exerts its protective effect against CYP-induced hepatotoxicity through upregulation of hepatic PPARγ expression and abrogation of inflammation and oxidative stress.

B-Cell Chronic Lymphocytic Leukemia Cells Express a Functional Inducible Nitric Oxide Synthase Displaying Anti-Apoptotic Activity

Blood ◽  
1998 ◽  
Vol 92 (3) ◽  
pp. 1031-1043 ◽  
Author(s):  
Haixia Zhao ◽  
Nathalie Dugas ◽  
Claire Mathiot ◽  
Alain Delmer ◽  
Bernard Dugas ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Chronic Lymphocytic Leukemia ◽  
Nitric Oxide Synthase ◽  
B Cell ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Inos Mrna ◽  
Nos Inhibitors ◽  
Oxide Synthase ◽  
Cell Chronic Lymphocytic Leukemia

Abstract The expression of different isoforms of nitric oxide synthase (NOS) was investigated in B-cell chronic lymphocytic leukemia (B-CLL) to delineate a possible role for nitric oxide (NO) in the control of apoptosis of the tumoral cells. By reverse transcription-polymerase chain reaction (RT-PCR), all B-CLL cells were found to express spontaneously inducible NOS (iNOS) mRNA, whereas endothelial constitutive NOS (ecNOS) mRNA was undetectable. The iNOS protein was detected by immunofluorescence in the cytoplasm of permeabilized leukemic cells and identified by Western blotting, using different anti-iNOS antibodies, as a protein of 135 kD in B-CLL cytoplasmic extracts. B-CLL cell lysates also displayed basal NOS enzymatic activity, as measured by the conversion of14C-labeled L-arginine into 14C-L-citrulline. Ligation of CD23, expressed on the vast majority of B-CLL cells, resulted in increased iNOS expression and activity. The NO released exerted an anti-apoptotic effect on B-CLL cells that was counteracted by NOS inhibitors and engagement of the APO-1/Fas pathway. Therefore, the existence of a functional iNOS in B-CLL cells will provide further insights into the mechanisms that control proliferation and apoptosis in these tumor cells. © 1998 by The American Society of Hematology.

Abstract 13115: Nitric Oxide Differentially Regulates White and Brown Adipogenesis Through Effects on Thermogenesis and Mitochondrial Biogenesis (Best of Basic Science Abstract)

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Paul Huang ◽  
Sylvia Lee-Huang
Keyword(s):  
Nitric Oxide ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Mitochondrial Biogenesis ◽  
Cold Exposure ◽  
Adipocyte Differentiation ◽  
Metabolic Effects ◽  
Gain Of Function ◽  
Brown Adipose ◽  
Brown Adipogenesis

Introduction: In addition to its roles as a vascular signaling molecule, nitric oxide (NO) plays roles in metabolism. Mice deficient in eNOS are overweight and develop insulin resistance. It is not known whether the metabolic effects are due to primary roles of NO, or to increased visceral adiposity, leading to secondary metabolic changes. Hypothesis: We hypothesized that NO plays distinct and separable primary roles in white and brown adipogenesis, which underlie the effects on adiposity, energy metabolism, and expression of thermogenic genes. Methods: We exposed wild-type and mice carrying specific gain of function and loss of function eNOS mutations to cold at 4C for 48 hours and assessed expression of thermogenic gene programs in white and brown adipose tissue. To study cell autonomous effects, we differentiated adipocyte precursors from brown and white fat in the presence of NOS inhibitors and NO donors, as well as with siRNA to knockdown eNOS expression. Results: Cold exposure resulted in upregulation of the thermogenic gene program in brown adipose tissue. Animals carrying a gain of function mutation in eNOS showed increased UCP1 expression even without cold exposure. Induction of thermogenic genes was more pronounced in the animals with gain of function eNOS mutation. Differentiation of adipocyte precursors showed effects of eNOS on adipogenesis. Cells treated with the pharmacologic blockade (L-NAME and L-NA) as well as genetic knockdown (siRNA) showed dose-dependent inhibition of adipocyte differentiation. MitoTracker Red CMXRos staining showed that treatment with the NO donor SNAP increases mitochondrial biogenesis, while L-NAME decreases mitochondrial biogenesis. Conclusions: We show that eNOS-derived NO plays distinct and separable roles in white and brown adipogenesis. In brown adipocytes, eNOS regulates the expression of the thermogenic gene program, with upregulation of expression even without cold exposure, and greater increase in response to cold. In white adipocytes, eNOS-derived NO is required for adipocyte differentiation and mitochondrial biogenesis.

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