scholarly journals Inducible Nitric Oxide Synthase in the Anterior Pituitary Gland: Induction by Interferon-γ in a Subpopulation of Folliculostellate Cells and in an Unidentifiable Population of Non-hormone-secreting Cells

1997 ◽  
Vol 45 (6) ◽  
pp. 847-857 ◽  
Author(s):  
Hugo Vankelecom ◽  
Patrick Matthys ◽  
Carl Denef
Keyword(s):  
Nitric Oxide ◽  
Cell Cultures ◽  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Endocrine System ◽  
Interferon Γ ◽  
S 100 ◽  
Ifn Γ ◽  
Oxide Synthase

In the context of immune-endocrine relationships, we have previously shown that interferon-γ (IFN-γ) inhibits hormone secretion in anterior pituitary (AP) cell cultures. The non-hormone-secreting folliculostellate (FS) cells were found to mediate this inhibitory action. Because in the immune system IFN-γ is a strong stimulator of nitric oxide (NO) release through the induction of NO synthase (NOS), we investigated whether the inducible form of NOS (iNOS) is present in (rat) AP cell cultures, and whether its expression is stimulated by IFN-γ. Immunocytochemistry revealed that under basal in vitro conditions only a very few AP cells contained iNOS. Treatment with IFN-γ caused a sixfold rise in the number of iNOS-positive cells and augmented the intensity of the staining. The increased number of iNOS-expressing cells was paralleled by elevated production of NO. Some of the iNOS-positive cells extended cytoplasmic processes between hormone-secreting cells, which is a characteristic of FS cells. Immunostaining of FS cell-poor and FS cell-enriched populations (obtained by gradient sedimentation) also suggested the presence of iNOS in a subpopulation of FS cells. By double immunofluorescence techniques we found that about 65% of iNOS-expressing cells were positive for S-100, a marker protein for FS cells. However, around 80% of the S-100-positive cells were not labeled for iNOS. On the other hand, the majority of the S-100-negative iNOS-containing cells could not be further identified by antisera against the classical AP hormones, suggesting the presence of iNOS in a still unidentified non-hormone-secreting cell type of the AP gland. This report is the first to demonstrate the expression of the inducible form of NOS in the AP gland. IFN-γ upregulates this expression, showing that cytokines may use the same signaling mechanisms in both the immune and the endocrine system. In addition, a putative new function of a subpopulation of FS cells in the paracrine regulation of the AP gland is suggested.

scholarly journals MyD88 Primes Macrophages for Full-Scale Activation by Interferon-γ yet Mediates Few Responses to Mycobacterium tuberculosis

2003 ◽  
Vol 198 (7) ◽  
pp. 987-997 ◽  
Author(s):  
Shuangping Shi ◽  
Carl Nathan ◽  
Dirk Schnappinger ◽  
Jörg Drenkow ◽  
Michele Fuortes ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Large Scale ◽  
Nuclear Factor Κb ◽  
Interferon Γ ◽  
Full Scale ◽  
Enzyme Linked Immunosorbent Assay ◽  
Ifn Γ ◽  
Microbial Products ◽  
Oxide Synthase

Macrophages are activated from a resting state by a combination of cytokines and microbial products. Microbes are often sensed through Toll-like receptors signaling through MyD88. We used large-scale microarrays in multiple replicate experiments followed by stringent statistical analysis to compare gene expression in wild-type (WT) and MyD88−/− macrophages. We confirmed key results by quantitative reverse transcription polymerase chain reaction, Western blot, and enzyme-linked immunosorbent assay. Surprisingly, many genes, such as inducible nitric oxide synthase, IRG-1, IP-10, MIG, RANTES, and interleukin 6 were induced by interferon (IFN)-γ from 5- to 100-fold less extensively in MyD88−/− macrophages than in WT macrophages. Thus, widespread, full-scale activation of macrophages by IFN-γ requires MyD88. Analysis of the mechanism revealed that MyD88 mediates a process of self-priming by which resting macrophages produce a low level of tumor necrosis factor. This and other factors lead to basal activation of nuclear factor κB, which synergizes with IFN-γ for gene induction. In contrast, infection by live, virulent Mycobacterium tuberculosis (Mtb) activated macrophages largely through MyD88-independent pathways, and macrophages did not need MyD88 to kill Mtb in vitro. Thus, MyD88 plays a dynamic role in resting macrophages that supports IFN-γ–dependent activation, whereas macrophages can respond to a complex microbial stimulus, the tubercle bacillus, chiefly by other routes.

scholarly journals Characterization of the functional and growth properties of long-term cell cultures established from a human somatostatinoma

2006 ◽  
Vol 13 (1) ◽  
pp. 79-93 ◽  
Author(s):  
G Galli ◽  
R Zonefrati ◽  
A Gozzini ◽  
C Mavilia ◽  
V Martineti ◽  
...  
Keyword(s):  
Cell Cultures ◽  
Telomerase Activity ◽  
Interferon Γ ◽  
Tumour Regression ◽  
C Cells ◽  
Telomerase Inhibitor ◽  
C Cell ◽  
Ifn Γ

In somatostatinoma, a rare malignant somatostatin (SST)-secreting neoplasia, tumour regression is rarely observed, implying the need for novel antiproliferative strategies. Here, we characterized a long-term culture (SST-secreting cancer (SS-C cells)) established from a human somatostatinoma. High concentrations of SST and chromogranin A were released by SS-C cells and SST release was stimulated by depolarizing stimuli and inhibited by the SST analogue, octreotide. SS-C cells expressed mRNA for SST receptor (SSTR) subtypes 1, 2 and 4, being also able to bind native SST. Moreover, SS-C cells were positively stained with an antibody to SSTR2. SS-C cells also expressed interferon-γ (IFN-γ) receptor mRNA and measurable telomerase activity. Our findings indicate that in vitro exposure of SS-C cells to native SST-28, to octreotide, to IFN-γ, or to 3′-azido-3′deoxythymidine (AZT), a telomerase inhibitor, results in inhibition of SS-C cell proliferation. Concomitant with growth inhibition, apoptosis was detected in SST-, octreotide-, IFN-γ- or AZT-treated SS-C cell cultures. Taken together our results characterized native SST, SST analogues, IFN-γ and a telomerase inhibitor as growth-inhibiting and proapoptotic stimuli in cultured human somatostatinoma cells. Based on these findings, the potential of SST analogues, IFN-γ and AZT, alone or in combination, should be further explored in the medical treatment of somatostatinoma.

scholarly journals Aerosolized Gamma Interferon (IFN-γ) Induces Expression of the Genes Encoding the IFN-γ-Inducible 10-Kilodalton Protein but Not Inducible Nitric Oxide Synthase in the Lung during Tuberculosis

2004 ◽  
Vol 72 (3) ◽  
pp. 1275-1283 ◽  
Author(s):  
Bindu Raju ◽  
Yoshihiko Hoshino ◽  
Kenichi Kuwabara ◽  
Ilana Belitskaya ◽  
Savita Prabhakar ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inducible Nitric Oxide Synthase ◽  
Gamma Interferon ◽  
Standard Drug ◽  
Pulmonary Tb ◽  
Ifn Γ ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

ABSTRACT Gamma interferon (IFN-γ) is critical in the immune response against Mycobacterium tuberculosis. In an ongoing trial of aerosol IFN-γ in conjunction with standard drug therapy, we have observed activation of IFN signaling in bronchoalveolar lavage (BAL) cells from tuberculosis (TB) patients. We hypothesized that aerosol IFN-γ treatment of pulmonary TB would increase expression of genes important for the control of TB. We investigated the expression of downstream genes by measuring inducible nitric oxide synthase (iNOS) and the chemokine IFN-inducible 10-kDa protein (IP-10) by real-time quantitative reverse transcription-PCR. In vitro, M. tuberculosis induced IP-10, and IFN-γ stimulated this further, with no effect on iNOS expression. We studied 21 patients with pulmonary TB and 7 healthy subjects. Similar to the in vitro model, IP-10 mRNA was increased in BAL cells from TB patients and was augmented after treatment with aerosolized IFN-γ. TB was also associated with elevated iNOS mRNA, but aerosolized IFN-γ did not further enhance expression. Genomic analysis identified 1,300 of 4,058 genes expressed in BAL cells from six TB patients before and after 1 month of therapy, including aerosolized IFN-γ. However, only 15 genes were differentially regulated by IFN-γ. We conclude that iNOS and IP-10 mRNA expression is increased in TB but that aerosol IFN-γ treatment increases expression of few genes in the human lung.

scholarly journals Regulation of the mouse inducible-type nitric oxide synthase gene promoter by interferon-γ, bacterial lipopolysaccharide and NG-monomethyl-l-arginine

1996 ◽  
Vol 316 (1) ◽  
pp. 209-215 ◽  
Author(s):  
Alessandro WEISZ ◽  
Luigi CICATIELLO ◽  
Hiroyasu ESUMI
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Gene Promoter ◽  
Interferon Γ ◽  
Raw 264.7 Cells ◽  
Raw 264.7 ◽  
Promoter Activation ◽  
Inos Gene ◽  
Ifn Γ ◽  
Oxide Synthase

Cytokines and bacterial lipopolysaccharides (LPSs) stimulate nitric oxide production in macrophages by inducing transcription of the gene coding for the inducible isoform of nitric oxide synthase (iNOS). We have cloned the mouse iNOS gene promoter and analysed its structural features and its response to interferon-γ (IFN-γ) and Escherichia coli LPS in RAW 264.7 mouse macrophage-like cells. Transcription of a recombinant reporter gene including the promoter and 4 kb of its 5′-flanking DNA, linked to the bacterial chloramphenicol acetyltransferase (CAT) reporter gene, is stimulated by IFN-γ and, more efficiently, by LPS upon transient transfection in RAW 264.7 cells. Two upstream DNA regions are required for maximal promoter activation by LPS: the first maps between positions -1541 and -775 and the other between -420 and -47, with respect to the major transcriptional start site of the iNOS gene. The upstream-most region also mediates promoter trans-activation by IFN-γ. As reported earlier for transcription of the endogenous iNOS gene, combined stimulation of RAW 264.7 cells with IFN-γ and LPS results in lower activation of the transfected promoter, when compared with LPS alone. NG-Monomethyl-L-arginine, a competitive inhibitor of nitric oxide synthase activity, enhances iNOS gene mRNA induction and promoter activation by IFN-γ and LPS, indicating that nitric oxide can influence negatively the responsiveness of this gene to inducers. These results suggest the possibility of a negative regulatory feedback exerted by iNOS on the transcriptional activation of its own gene.

scholarly journals Immune Suppression by Recombinant Interleukin (rIL)-12 Involves Interferon γ Induction of Nitric Oxide Synthase 2 (iNOS) Activity: Inhibitors of NO Generation Reveal the Extent of rIL-12 Vaccine Adjuvant Effect

1998 ◽  
Vol 188 (9) ◽  
pp. 1603-1610 ◽  
Author(s):  
Holly Kurzawa Koblish ◽  
Christopher A. Hunter ◽  
Maria Wysocka ◽  
Giorgio Trinchieri ◽  
William M.F. Lee
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Immune Suppression ◽  
Neutralizing Antibodies ◽  
Vaccine Adjuvant ◽  
Interleukin 12 ◽  
Effective Vaccine ◽  
Ifn Γ ◽  
Oxide Synthase

Recombinant interleukin 12 (IL-12) can profoundly suppress cellular immune responses in mice. To define the underlying mechanism, recombinant murine (rm)IL-12 was given to C57BL/6 mice undergoing alloimmunization and found to transiently but profoundly suppress in vivo and in vitro allogeneic responses and in vitro splenocyte mitogenic responses. Use of neutralizing antibodies and genetically deficient mice showed that IFN-γ (but not TNF-α) mediated rmIL-12–induced immune suppression. Splenocyte fractionation studies revealed that adherent cells from rmIL-12–treated mice suppressed the mitogenic response of normal nonadherent cells to concanavalin A and IL-2. Addition of an inhibitor of nitric oxide synthase (NOS) restored mitogenic responses, and inducible (i)NOS−/− mice were not immunosuppressed by rmIL-12. These results support the view that suppression of T cell responses is due to NO produced by macrophages responding to the high levels of IFN-γ induced by rmIL-12. When a NOS inhibitor was given with rmIL-12 during vaccination of A/J mice with irradiated SCK tumor cells, immunosuppression was averted and the extent of rmIL-12's ability to enhance induction of protective antitumor immunity was revealed. This demonstrates that rmIL-12 is an effective vaccine adjuvant whose efficacy may be masked by its transient immunosuppressive effect.

scholarly journals Isoquinolinequinone Derivatives from a Marine Sponge (Haliclona sp.) Regulate Inflammation in In Vitro System of Intestine

Marine Drugs ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 90
Author(s):  
Yun Kim ◽  
Yeong Ji ◽  
Na-Hyun Kim ◽  
Nguyen Van Tu ◽  
Jung-Rae Rho ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Marine Sponge ◽  
Nuclear Translocation ◽  
Hydroxyl Group ◽  
Subsequent Increase ◽  
Inflammatory Bowel ◽  
Anti Inflammatory ◽  
Key Functional Groups ◽  
Oxide Synthase

Using bio-guided fractionation and based on the inhibitory activities of nitric oxide (NO) and prostaglandin E2 (PGE2), eight isoquinolinequinone derivatives (1–8) were isolated from the marine sponge Haliclona sp. Among these, methyl O-demethylrenierate (1) is a noble ester, whereas compounds 2 and 3 are new O-demethyl derivatives of known isoquinolinequinones. Compound 8 was assigned as a new 21-dehydroxyrenieramycin F. Anti-inflammatory activities of the isolated compounds were tested in a co-culture system of human epithelial Caco-2 and THP-1 macrophages. The isolated derivatives showed variable activities. O-demethyl renierone (5) showed the highest activity, while 3 and 7 showed moderate activities. These bioactive isoquinolinequinones inhibited lipopolysaccharide and interferon gamma-induced production of NO and PGE2. Expression of inducible nitric oxide synthase, cyclooxygenase-2, and the phosphorylation of MAPKs were down-regulated in response to the inhibition of NF-κB nuclear translocation. In addition, nuclear translocation was markedly promoted with a subsequent increase in the expression of HO-1. Structure-activity relationship studies showed that the hydroxyl group in 3 and 5, and the N-formyl group in 7 may be key functional groups responsible for their anti-inflammatory activities. These findings suggest the potential use of Haliclona sp. and its metabolites as pharmaceuticals treating inflammation-related diseases including inflammatory bowel disease.

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