scholarly journals A Novel Effect of Growth Hormone on Macrophage Modulates Macrophage-Dependent Adipocyte Differentiation

Endocrinology ◽  
2010 ◽  
Vol 151 (5) ◽  
pp. 2189-2199 ◽  
Author(s):  
Chunxia Lu ◽  
P. Anil Kumar ◽  
Yong Fan ◽  
Mark A. Sperling ◽  
Ram K. Menon
Keyword(s):  
Adipocyte Differentiation ◽  
Nuclear Factor Κb ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Nuclear Factor ◽  
Preadipocyte Differentiation ◽  
Precise Role ◽  
Vascular Compartment ◽  
Specific Deletion

The GH receptor (GHR) is expressed on macrophages. However, the precise role of GH in regulation of macrophage function is unclear. We hypothesized that soluble factors including cytokines produced by macrophages in a GH-dependent manner regulate adipogenesis. We confirmed expression and functional integrity of the GHR in the J774A.1 macrophage cells. Conditioned medium (CM) from macrophages inhibited adipogenesis in a 3T3-L1 adipogenesis assay. CM from GH-treated macrophages decreased the inhibitory effect of CM from macrophages on adipogenesis. This effect on preadipocyte differentiation was active only during the first (early) phase of adipocyte differentiation. CM from stromal vascular compartment macrophages of mice with macrophage-specific deletion of the GHR exhibited more inhibitory effect on 3T3-L1 preadipocyte differentiation compared with CM from stromal vascular compartment macrophages of control mice, indicating that intact GH action in primary macrophages also increases preadipocyte differentiation. GH did not increase IGF-1 expression in macrophages. PCR array analysis identified IL-1β as a candidate cytokine whose expression was altered by GH in macrophages. Levels of IL-1β mRNA and protein were significantly decreased in GH-treated J774A.1 macrophages. Nuclear factor-κB stimulates IL-1β gene expression, and GH induced a significant decrease in the levels of phosphorylated nuclear factor-κB in macrophages. IL-1β is a known inhibitor of adipogenesis, and these results support GH-dependent down-regulation of macrophage IL-1β expression as one mechanism for the observed increase in adipogenesis with CM from GH-treated macrophages. We conclude that GH decreases secretion of IL-1β by the macrophage and thus in a paracrine manner increases adipocyte differentiation. These results provide a novel mechanism for GH’s actions in the control of adipogenesis.

Role of tumour necrosis factor receptor-1 and nuclear factor-κB in production of TNF-α-induced pro-inflammatory microparticles in endothelial cells

2014 ◽  
Vol 112 (09) ◽  
pp. 580-588 ◽  
Author(s):  
Sung Kyul Lee ◽  
Seung-Hee Yang ◽  
Il Kwon ◽  
Ok-Hee Lee ◽  
Ji Hoe Heo
Keyword(s):  
Endothelial Cells ◽  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Nuclear Factor Κb ◽  
Tumour Necrosis Factor Receptor ◽  
Dependent Manner ◽  
Nuclear Factor ◽  
Tnf Α ◽  
Necrosis Factor

SummaryTumour necrosis factor-α (TNF-α) is upregulated in many inflammatory diseases and is also a potent agent for microparticle (MP) generation. Here, we describe an essential role of TNF-α in the production of endothelial cell-derived microparticles (EMPs) in vivo and the function of TNF-α-induced EMPs in endothelial cells. We found that TNF-α rapidly increased blood levels of EMPs in mice. Treatment of human umbilical vein endothelial cells (HUVECs) with TNF-α also induced EMP formation in a time-dependent manner. Silencing of TNF receptor (TNFR)-1 or inhibition of the nuclear factor-κB (NF-κB) in HUVECs impaired the production of TNF-α-induced EMP. Incubation of HUVECs with PKH-67-stained EMPs showed that endothelial cells readily engulfed EMPs, and the engulfed TNF-α-induced EMPs promoted the expression of pro-apoptotic molecules and upregulated intercellular adhesion molecule-1 level on the cell surface, which led to monocyte adhesion. Collectively, our findings indicate that the generation of TNF-α-induced EMPs was mediated by TNFR1 or NF-κB and that EMPs can contribute to apoptosis and inflammation of endothelial cells.

scholarly journals p38 MAPK-induced Nuclear Factor-κB Activity Is Required for Skeletal Muscle Differentiation: Role of Interleukin-6

2004 ◽  
Vol 15 (4) ◽  
pp. 2013-2026 ◽  
Author(s):  
Bernat Baeza-Raja ◽  
Pura Muñoz-Cánoves
Keyword(s):  
Signaling Pathways ◽  
P38 Mapk ◽  
Myogenic Differentiation ◽  
Nuclear Factor Κb ◽  
Binding Activity ◽  
C2c12 Cells ◽  
Myoblast Differentiation ◽  
Dependent Manner ◽  
Nuclear Factor

p38 MAPK and nuclear factor-κB (NF-κB) signaling pathways have been implicated in the control of skeletal myogenesis. However, although p38 is recognized as a potent activator of myoblast differentiation, the role of NF-κB remains controversial. Here, we show that p38 is activated only in differentiating myocytes, whereas NF-κB activity is present both in proliferation and differentiation stages. NF-κB activation was found to be dependent on p38 activity during differentiation, being NF-κB an effector of p38, thus providing a novel mechanism for the promyogenic effect of p38. Activation of p38 in C2C12 cells induced the activity of NF-κB, in a dual way: first, by reducing IκBα levels and inducing NF-κB-DNA binding activity and, second, by potentiating the transactivating activity of p65-NF-κB. Finally, we show that interleukin (IL)-6 expression is induced in C2C12 differentiating myoblasts, in a p38- and NF-κB-dependent manner. Interference of IL-6 mRNA reduced, whereas its overexpression increased, the extent of myogenic differentiation; moreover, addition of IL-6 was able to rescue significantly the negative effect of NF-κB inhibition on this process. This study provides the first evidence of a crosstalk between p38 MAPK and NF-κB signaling pathways during myogenesis, with IL-6 being one of the effectors of this promyogenic mechanism.

ROLE OF NUCLEAR FACTOR κB IN MELANOMA PROGRESSION.

2007 ◽  
Vol 55 (1) ◽  
pp. S158
Author(s):  
A. M. DeLuca ◽  
B. Ryu ◽  
R. Alani
Keyword(s):  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Melanoma Progression

scholarly journals Activation of Nuclear Factor κB and Induction of Inducible Nitric Oxide Synthase by Ureaplasma urealyticumin Macrophages

2000 ◽  
Vol 68 (12) ◽  
pp. 7087-7093 ◽  
Author(s):  
Y.-H. Li ◽  
Z.-Q. Yan ◽  
J. Skov Jensen ◽  
K. Tullus ◽  
A. Brauner
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inducible Nitric Oxide Synthase ◽  
Alveolar Macrophages ◽  
Nuclear Factor Κb ◽  
Inos Expression ◽  
Dependent Manner ◽  
Nuclear Factor ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

ABSTRACT Chronic lung disease (CLD) of prematurity is an inflammatory disease with a multifactorial etiology. The importance ofUreaplasma urealyticum in the development of CLD is debated, and steroids produce some improvement in neonates with this disease. In the present study, the capability of U. urealyticum to stimulate rat alveolar macrophages to produce nitric oxide (NO), express inducible nitric oxide synthase (iNOS), and activate nuclear factor κB (NF-κB) in vitro was characterized. The effect of NO on the growth of U. urealyticum was also investigated. In addition, the impact of dexamethasone and budesonide on these processes was examined. We found that U. urealyticum antigen (≥4 × 107 color-changing units/ml) stimulated alveolar macrophages to produce NO in a dose- and time-dependent manner (P < 0.05). This effect was further enhanced by gamma interferon (100 IU/ml; P < 0.05) but was attenuated by budesonide and dexamethasone (10−4 to 10−6 M) (P < 0.05). The mRNA and protein levels of iNOS were also induced in response to U. urealyticum and inhibited by steroids.U. urealyticum antigen triggered NF-κB activation, a possible mechanism for the induced iNOS expression, which also was inhibited by steroids. NO induced by U. urealyticum caused a sixfold reduction of its own growth after infection for 10 h. Our findings imply that U. urealyticum may be an important factor in the development of CLD. The host defense response againstU. urealyticum infection may also be influenced by NO. The down-regulatory effect of steroids on NF-κB activation, iNOS expression, and NO production might partly explain the beneficial effect of steroids in neonates with CLD.

Role of nuclear factor-κB in gastric ulcer healing in rats

2001 ◽  
Vol 280 (6) ◽  
pp. G1296-G1304 ◽  
Author(s):  
Satoru Takahashi ◽  
Takuya Fujita ◽  
Akira Yamamoto
Keyword(s):  
Gastric Ulcer ◽  
Mrna Expression ◽  
Ulcer Healing ◽  
Nuclear Factor Κb ◽  
Normal Mucosa ◽  
Cyclooxygenase 2 ◽  
Interleukin 1Β ◽  
Nuclear Factor ◽  
Gastric Ulcer Healing

We investigated the role of nuclear factor-κB (NF-κB) in gastric ulcer healing in rats. NF-κB was activated in ulcerated tissue but not in normal mucosa, and the level of the activation was decreased with ulcer healing. NF-κB activation was observed in fibroblasts, monocytes/macrophages, and neutrophils. Treatment of gastric fibroblasts, isolated from the ulcer base, with interleukin-1β activated NF-κB and the subsequently induced cyclooxygenase-2 and cytokine-induced neutrophil chemoattractant-1 (CINC-1) mRNA expression. Inhibition of activated NF-κB action resulted in suppression of both their mRNA expression and increases in PGE2 and CINC-1 levels induced by interleukin-1β. Persistent prevention of NF-κB activation caused an impairment of ulcer healing in rats. Gene expression of interleukin-1β, CINC-1, cyclooxygenase-2, and inducible nitric oxide synthase in ulcerated tissue had been inhibited before the delay in ulcer healing became manifest. The increased levels of cyclooxygenase-2 protein and PGE2 production were also reduced. These results demonstrate that NF-κB, activated in ulcerated tissue, might upregulate the expression of healing-promoting factors responsible for gastric ulcer healing in rats.

scholarly journals Sec1p directly stimulates SNARE-mediated membrane fusion in vitro

2004 ◽  
Vol 167 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Brenton L. Scott ◽  
Jeffrey S. Van Komen ◽  
Hassan Irshad ◽  
Song Liu ◽  
Kirilee A. Wilson ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Fusion ◽  
Membrane Trafficking ◽  
Snare Complex ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Bud Neck ◽  
Precise Role

Sec1 proteins are critical players in membrane trafficking, yet their precise role remains unknown. We have examined the role of Sec1p in the regulation of post-Golgi secretion in Saccharomyces cerevisiae. Indirect immunofluorescence shows that endogenous Sec1p is found primarily at the bud neck in newly budded cells and in patches broadly distributed within the plasma membrane in unbudded cells. Recombinant Sec1p binds strongly to the t-SNARE complex (Sso1p/Sec9c) as well as to the fully assembled ternary SNARE complex (Sso1p/Sec9c;Snc2p), but also binds weakly to free Sso1p. We used recombinant Sec1p to test Sec1p function using a well-characterized SNARE-mediated membrane fusion assay. The addition of Sec1p to a traditional in vitro fusion assay moderately stimulates fusion; however, when Sec1p is allowed to bind to SNAREs before reconstitution, significantly more Sec1p binding is detected and fusion is stimulated in a concentration-dependent manner. These data strongly argue that Sec1p directly stimulates SNARE-mediated membrane fusion.

Role Of Cyclic Amp In The Inhibition Of Human Platelet Functions By Quercetin, A Flav0N0Id That Potentiates PGI2 Effect

1981 ◽  
Author(s):  
J P Cazenave ◽  
A Beretz ◽  
A Stierlé ◽  
R Anton
Keyword(s):  
Maximum Level ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Pde Inhibitors ◽  
Pde Inhibition ◽  
Induced Aggregation ◽  
Camp Levels ◽  
Dose Dependent

Injury to the endothelium (END) and subsequent platelet (PLAT)interactions with the subEND are important steps in thrombosis and atherosclerosis. Thus,drugs that protect the END from injury and also inhibit PLAT function are of interest. It has been shown that some flavonoids(FLA), a group of compounds found in plants, prevent END desquamation in vivo, inhibit cyclic nucleotide phosphodiesterases(PDE)and inhibit PLAT function. We have studied the structure-activity relationships of 13 purified FLA on aggregation and secretion of 14c-5HT of prelabeled washed human PLAT induced by ADP, collagen(COLL) and thrombin(THR). All the FLA were inhibitors of the 3 agents tested. Quercetin(Q), was the second best after fisetin. It inhibited secretion and aggregation with I50 of 330µM against 0.1 U/ML.THR, 102µM against 5µM ADP and 40 µM against COLL. This inhibitory effect is in the range of that of other PDE inhibitors like dipyridamole or 3-isobutyl-l- methylxanthine. The aggregation induced by ADP, COLL and THR is at least mediated by 3 mechanisms that can be inhibited by increasing cAMP levels. We next investigated if Q, which is a PDE inhibitor of bovine aortic microsomes,raises PLAT cAMP levels. cAMP was measured by a protein-binding method. ADP- induced aggregation(5µM) was inhibited by PGI2 (0.1 and 0.5 nM) . Inhibition was further potentiated(l.7 and 3.3 times) by lOµM Q, which alone has no effect on aggregation. The basal level of cAMP(2.2 pmol/108PLAT) was not modified by Q (50 to 500µM). Using these concentrations of Q,the rise in cAMP caused by PGI2(0.1 and 0.5nM) was potentiated in a dose dependent manner. Q potentiated the effect of PGI2 on the maximum level of cAMP and retarded its breakdown. Thus Q and possibly other FLA could inhibit the interaction of PLAT with the components of the vessel wall by preventing END damage and by inhibiting PLAT function through a rise in cAMP secondary to PDE inhibition and potentiation of the effect of vascular PGI2 on PLAT adenylate cyclase.

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