scholarly journals Function and regulation of a murine macrophage-specific IgG Fc receptor, Fc gamma R-alpha.

1988 ◽  
Vol 167 (6) ◽  
pp. 1909-1925 ◽  
Author(s):  
R L Weinshank ◽  
A D Luster ◽  
J V Ravetch

Ligand binding specificities of two cloned murine Fc gamma Rs (Fc gamma R-alpha, Fc gamma R-beta [9]) were determined by gene transfer into Fc gamma R negative cell lines. Both receptors were expressed as full-length molecules capable of IgG immune complex binding that was inhibitable by the mAb 2.4G2. The ligand binding profiles of these receptors were indistinguishable whereby both bound immune-complexed mouse IgG1, IgG2a, and IgG2b, but not IgG3. Neither receptor could bind monomeric IgG2a, indicating these receptors to be low-affinity IgG Fc receptors. Accumulation of the Fc gamma R-alpha mRNA can be induced with murine IFN-gamma at a concentration of 200 U/ml in the macrophage-like cell lines RAW 264.7 and J774a. The time course for induction indicates that the mRNA accumulation is transient but does not return to the uninduced level even after 50 h of treatment. Fc gamma R-beta mRNA was not induced by IFN-gamma, rather its expression was down modulated in mouse peritoneal macrophages. Both RAW and J774a cells lines exhibited increased receptor levels after IFN-gamma stimulation as measured by 125I-2.4G2 and ligand binding. In the absence of IFN-gamma, the RAW and J774a cell lines were minimally phagocytic, while P388D1 cells were actively phagocytic. In the presence of IFN-gamma, however, RAW 264.7 and J774a cells were induced to become actively phagocytic. Induction of Fc gamma R-alpha mRNA and protein by IFN-gamma may be part of the process by which macrophages become activated to engulf antibody-coated particles.

1980 ◽  
Vol 152 (5) ◽  
pp. 1236-1247 ◽  
Author(s):  
C A Rouzer ◽  
W A Scott ◽  
A L Hamill ◽  
Z A Cohn

A method for the radiochemical assay of LTC production by mouse peritoneal macrophages in vitro is presented. The method involves labeling macrophages in culture with [5,6,8,9,11,12,14,15-3H]20:4 followed by stimulation of arachidonic acid (20:4) release under the experimental conditions desired. Radiolabeled leukotriene C (LTC) is recovered from the culture medium by extraction and silicic acid chromatography in 40% yield with full retention of biological activity. Because this LTC is radiochemically pure, the quantity of LTC release may be estimated from the amount of radioactivity in the sample. Use of the radioassay to study parameters affecting LTC synthesis by macrophages indicated that the time course of LTC synthesis and its relationship to the dose of a phagocytic stimulus (zymosan) were very similar to those of prostaglandin (PG) release. LTC release was also similar to that of PG in that lower levels of both metabolites were produced by Corynebacterium parvum-elicited macrophages than by resident cells. Finally, LTC release was stimulated in response to a challenge with antigen-antibody complexes, but lower maximal levels were attained than those with zymosan. The data presented here are consistent with the hypothesis that challenge of macrophages with a phagocytic stimulus leads to the release of 20:4 by an inducible phospholipase. Cyclooxygenase and lipoxygenase then compete for the released 20:4, leading to the production of PG, hydroxyeicosatetraenoic acids, and LTC.


1987 ◽  
Vol 166 (6) ◽  
pp. 1912-1917 ◽  
Author(s):  
A H Warfel ◽  
D Zucker-Franklin ◽  
B Frangione ◽  
J Ghiso

Cystatin C (gamma-trace) was found to be a constitutively secreted protein of isolated human monocytes and mouse peritoneal macrophages, as well as the histiocytic lymphoma cell lines U937, P388D.1, and J774. This proteinase inhibitor is not uniquely secreted by monocytes/macrophages, but was also identified in the conditioned media from several primary cells, including brain cells, and diverse established cell lines. In vitro treatment of resident mouse peritoneal macrophages with either LPS or IFN-gamma caused a downregulation in cystatin C secretion. Elaboration of this protein was also diminished by macrophages that had been stimulated by thioglycollate in vivo, and treatment of these cells with LPS led to further decline. It is suggested that, under some inflammatory conditions, downregulation of cystatin C may contribute to tissue pathology.


1995 ◽  
Vol 310 (2) ◽  
pp. 547-551 ◽  
Author(s):  
H Sato ◽  
K Fujiwara ◽  
J Sagara ◽  
S Bannai

The transport of cystine has been investigated in mouse peritoneal macrophages cultured in vitro. The transport activity for cystine was very low in freshly isolated macrophages but was potently induced during culture in the presence of bacterial lipopolysaccharide (LPS) at concentrations as low as 0.1 ng/ml. The transport activity for cystine was enhanced when the cells were incubated with tumour necrosis factor-alpha (TNF-alpha), but not with interferon-gamma (IFN-gamma) or interleukin-1. IFN-gamma was rather repressive in the induction of the activity by LPS or TNF-alpha. The transport activity for cystine induced by LPS has been characterized. Cystine was transported mainly by Na(+)-independent system and the uptake of cystine was inhibited by extracellular glutamate and homocysteate, but not by aspartate, indicating that the transport of cystine in macrophages treated with LPS is mediated by System xc-. Glutathione content of the macrophages increased when they were exposed to LPS, and this increase was, at least in part, attributable to the induced activity of the cystine transport.


1971 ◽  
Vol 134 (4) ◽  
pp. 947-962 ◽  
Author(s):  
Saimon Gordon ◽  
Zanvil Cohn

Mouse peritoneal macrophages possess a specific plasma membrane receptor for antibody-coated particles. Sheep red cells coated with rabbit 7S antibody attach readily to the macrophage surface and are subsequently interiorized. The fusion of macrophage with nonphagocytic mouse melanoma cells produces heterokaryons in which the macrophage receptor is drastically altered. The receptor is present shortly after fusion and heterokaryons are actively phagocytic. The ability to bind and ingest red cells is, however, progressively lost over the next 12–24 hr and does not reappear thereafter. Exposure of heterokaryons to trypsin (1–100 µg/ml for 30 min at 37°C) results in the reappearance of initial receptor activity and the unmasking of the surface receptor. This property is again lost upon subsequent cultivation. The masking process takes place when cells are cultivated in the absence of IgG so that the adsorption of antibody from the medium is not responsible for this phenomenon. Inhibition of heterokaryon protein synthesis preserves phagocytic activity in a reversible fashion and prevents the masking of macrophage receptors. Inhibition of melanoma RNA synthesis before fusion is also able to block subsequent masking, but is ineffective if delayed until after fusion. Ultraviolet irradiation of the melanoma cell before fusion prevents subsequent masking, whereas similar treatment of the macrophage has no effect. Cells differ markedly in their ability to mask the macrophage phagocytic receptor after fusion. Ehrlich ascites tumor cells mask the receptor rapidly, primary chick fibroblasts minimally, and embryonic chick erythrocytes not at all.


2008 ◽  
Vol 295 (1) ◽  
pp. C2-C12 ◽  
Author(s):  
Nitza Lahat ◽  
Michal A. Rahat ◽  
Amalia Kinarty ◽  
Lea Weiss-Cerem ◽  
Sigalit Pinchevski ◽  
...  

Infection, simulated by lipopolysaccharide (LPS), is a potent stimulator of tumor necrosis factor-α (TNF-α) production, and hypoxia often synergizes with LPS to induce higher levels of the secreted cytokine. However, we show that in primary mouse peritoneal macrophages and in three mouse peritoneal macrophage cell lines (RAW 264.7, J774A.1, and PMJ-2R), hypoxia (O2 < 0.3%) reduces the secretion of LPS-induced TNF-α ( P < 0.01). In RAW 264.7 cells this reduction was not regulated transcriptionally as TNF-α mRNA levels remained unchanged. Rather, hypoxia and LPS reduced the intracellular levels of TNF-α by twofold ( P < 0.01) by enhancing its degradation in the lysosomes and inhibiting its secretion via secretory lysosomes, as shown by confocal microscopy and verified by the use of the lysosome inhibitor Bafilomycin A1. In addition, although hypoxia did not change the accumulation of the soluble receptor TNF-RII, it increased its binding to the secreted TNF-α by twofold ( P < 0.05). We suggest that these two posttranslational regulatory checkpoints coexist in hypoxia and may partially explain the reduced secretion and diminished biological activity of TNF-α in hypoxic peritoneal macrophages.


2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Hiroshi Kitamura ◽  
Takeshi Ishino ◽  
Yoshinori Shimamoto ◽  
Jun Okabe ◽  
Tomomi Miyamoto ◽  
...  

We investigated the regulatory roles of USP2 in mRNA accumulation of proinflammatory cytokines in macrophage-like cells after stimulation with a toll-like receptor (TLR) 4 ligand, lipopolysaccharide (LPS). Human macrophage-like HL-60 cells, mouse macrophage-like J774.1 cells, and mouse peritoneal macrophages demonstrated negative feedback to USP2 mRNA levels after LPS stimulation, suggesting that USP2 plays a significant role in LPS-stimulated macrophages.USP2knockdown (KD) by short hairpin RNA in HL-60 cells promoted the accumulation of transcripts for 25 of 104 cytokines after LPS stimulation. In contrast, limited induction of cytokines was observed in cells forcibly expressing the longer splice variant of USP2 (USP2A), or in peritoneal macrophages isolated fromUsp2atransgenic mice. An ubiquitin isopeptidase-deficient USP2A mutant failed to suppress LPS-induced cytokine expression, suggesting that protein ubiquitination contributes to USP2-mediated cytokine repression. Although USP2 deficiency did not accelerate TNF receptor-associated factor (TRAF) 6-nuclear factor-κB (NF-κB) signaling, it increased the DNA binding ratio of the octamer binding transcription factor (Oct)-1 to Oct-2 inTNF,CXCL8,CCL4, andIL6promoters. USP2 decreased nuclear Oct-2 protein levels in addition to decreasing the polyubiquitination of Oct-1. In summary, USP2 modulates proinflammatory cytokine induction, possibly through modification of Oct proteins, in macrophages following TLR4 activation.


1987 ◽  
Vol 165 (3) ◽  
pp. 733-749 ◽  
Author(s):  
A Ding ◽  
S D Wright ◽  
C Nathan

Several features of activation of mouse peritoneal macrophages were elicited by 1-2-d exposure to submicrogram concentrations of anti-Mac-1 (M1/70), a rat monoclonal antibody that reacts with the alpha chain of complement receptor type 3 (Mac-1). The changes induced included enhanced capacity to secrete H2O2 when triggered with PMA, decreased secretion of proteins, increased expression of Ia antigen and decreased phagocytosis of particles. These changes closely resembled those induced by rIFN-gamma in type, extent, and time course. The concentration of M1/70 IgG resulting in 50% of the maximal activation of macrophage H2O2-releasing capacity averaged 0.18 +/- 0.03 micrograms/ml. This activation was not blocked by anti-FcR mAb, and could be reproduced with M18/2, a mAb against beta chain of Mac-1, suggesting that a direct ligation of Mac-1 with mAb was responsible for the activation. Neither depletion of T cells nor addition of neutralizing Abs to IFN-gamma or TNF-alpha prevented M1/70-mediated macrophage activation. Moreover, F(ab')2 of M1/70, or plating of macrophages on C3bi-coated surfaces, inhibited the activation of macrophages by rIFN-gamma. These findings suggest that Mac-1 (CR3) may play an important role in macrophage activation.


2000 ◽  
Vol 74 (19) ◽  
pp. 9240-9244 ◽  
Author(s):  
Akiko Shiratsuchi ◽  
Masako Kaido ◽  
Takenori Takizawa ◽  
Yoshinobu Nakanishi

ABSTRACT Influenza virus induces apoptosis in cultured cell lines as well as in animal tissues. HeLa cells were infected with influenza virus A/Udon/72 (H3N2) under conditions resulting in almost 100% infection. Such cells underwent typical caspase-dependent apoptosis and were efficiently phagocytosed by macrophages prepared from peritoneal fluids of thioglycolate-treated mice. The membrane phospholipid phosphatidylserine appeared on the surfaces of virus-infected cells at around the time efficient phagocytosis became detectable. In fact, the phagocytosis was almost completely inhibited in the presence of liposomes containing phosphatidylserine, which did not influence the antibody-dependent uptake of zymosan particles by the same macrophages. These results indicate that macrophages phagocytose influenza virus-infected HeLa cells in a manner mediated by phosphatidylserine that appears on the surfaces of infected cells during the process of apoptosis.


Blood ◽  
1998 ◽  
Vol 92 (12) ◽  
pp. 4742-4749 ◽  
Author(s):  
Julie M. Tebo ◽  
Hee Sun Kim ◽  
Jing Gao ◽  
David A. Armstrong ◽  
Thomas A. Hamilton

Interleukin-10 (IL-10) selectively inhibited lipopolysaccharide (LPS)-induced chemoattractant cytokine gene expression: levels of IP-10 mRNA were markedly suppressed in IL-10–treated mouse peritoneal macrophages, whereas the expression of the RANTES mRNA was only modestly reduced. IL-10 inhibited IP-10 mRNA accumulation by reducing IP-10 gene transcription as demonstrated by nuclear run-on analysis. Interestingly, the ability of IL-10 to inhibit expression of IP-10 was dependent on the inducing stimulus; IL-10 did not suppress interferon γ (IFNγ)- or IFNβ-stimulated IP-10 transcription or mRNA accumulation. These results suggested that IL-10 might act indirectly to suppress IP-10 expression by inhibiting LPS-induced class I IFN production. This hypothesis was supported by the following observations. First, LPS-induced IP-10 mRNA expression was blocked in cells cotreated with cycloheximide. Second, IL-10 inhibited the production of IFN/β-mediated antiviral activity. Finally, the IL-10–mediated suppression of LPS-stimulated IP-10 production could be rescued by cotreatment with IFNβ.


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