scholarly journals Tetrahydrobiopterin and alkylglycerol monooxygenase substantially alter the murine macrophage lipidome

2015 ◽  
Vol 112 (8) ◽  
pp. 2431-2436 ◽  
Author(s):  
Katrin Watschinger ◽  
Markus A. Keller ◽  
Eileen McNeill ◽  
Mohammad T. Alam ◽  
Steven Lai ◽  
...  

Tetrahydrobiopterin is a cofactor synthesized from GTP with well-known roles in enzymatic nitric oxide synthesis and aromatic amino acid hydroxylation. It is used to treat mild forms of phenylketonuria. Less is known about the role of tetrahydrobiopterin in lipid metabolism, although it is essential for irreversible ether lipid cleavage by alkylglycerol monooxygenase. Here we found intracellular alkylglycerol monooxygenase activity to be an important regulator of alkylglycerol metabolism in intact murine RAW264.7 macrophage-like cells. Alkylglycerol monooxygenase was expressed and active also in primary mouse bone marrow-derived monocytes and “alternatively activated” M2 macrophages obtained by interleukin 4 treatment, but almost missing in M1 macrophages obtained by IFN-γ and lipopolysaccharide treatment. The cellular lipidome of RAW264.7 was markedly changed in a parallel way by modulation of alkylglycerol monooxygenase expression and of tetrahydrobiopterin biosynthesis affecting not only various ether lipid species upstream of alkylglycerol monooxygenase but also other more complex lipids including glycosylated ceramides and cardiolipins, which have no direct connection to ether lipid pathways. Alkylglycerol monooxygenase activity manipulation modulated the IFN-γ/lipopolysaccharide–induced expression of inducible nitric oxide synthase, interleukin-1β, and interleukin 1 receptor antagonist but not transforming growth factor β1, suggesting that alkylglycerol monooxygenase activity affects IFN-γ/lipopolysaccharide signaling. Our results demonstrate a central role of tetrahydrobiopterin and alkylglycerol monooxygenase in ether lipid metabolism of murine macrophages and reveal that alteration of alkylglycerol monooxygenase activity has a profound impact on the lipidome also beyond the class of ether lipids.

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Sara McCurdy ◽  
William A Boisvert

Macrophage accumulation is a key process affecting all stages of atherosclerosis. Whether these cells accumulate in plaque solely by recruitment of monocytes from circulation or by proliferation within the plaque is an important question that has garnered much interest in recent years. Originally identified as a lymphocyte activation marker, CD98hc (SLC3A2) is a transmembrane protein involved in cell proliferation and survival via integrin signaling and MAP kinase activation. We hypothesized that CD98hc deficiency in myeloid cells would have a protective effect on atherosclerosis development and plaque composition by limiting macrophage proliferation. For the studies described, we utilized mice with myeloid-specific deletion of the CD98hc ( CD98hc fl/fl LysMCre + ) to determine the effects of CD98hc deficiency on macrophage function in the context of atherosclerosis . We performed in vitro assays to investigate the role of CD98hc in the proliferation and survival of primary mouse bone marrow derived macrophages. Although we found no differences in the number of bone marrow cells isolated from control or CD98hc -/- animals, after differentiation with MCS-F for 7 days, the number of macrophages obtained from CD98hc -/- mice was approximately 80% lower (7.2 ± 2.2 x 10 6 vs. 42.4 ± 4.6 x 10 6 per mouse) compared to control mice. Proliferation assays in vitro using EdU revealed approximately 50% (15.4 ± 2.5% vs. 7.5±1.8%) reduced cell proliferation in CD98hc -/- macrophages compared to control cells that could not be rescued with the addition M-CSF. In a 6-week atherosclerosis study using Ldlr -/- CD98hc fl/fl LysMCre + mice, Oil-Red O staining of whole aortae as well as aortic sinus sections showed that atherosclerotic plaque development was reduced compared to Ldlr -/- CD98hc fl/fl LysMCre - control mice. Additionally, immunohistochemical staining of atherosclerotic tissues revealed a reduction in macrophage abundance and proliferation within the plaque of Ldlr -/- CD98hc fl/fl LysMCre + mice compared to control mice. These findings support an important role of CD98hc in macrophage proliferation within the plaque environment, and provide a novel target for reducing atherosclerosis.


1996 ◽  
Vol 5 (1) ◽  
pp. 62-68 ◽  
Author(s):  
Dominique Vaillier ◽  
Richard Daculsi ◽  
Norbert Gualdel

The production of nitric oxide (NO) was measured in cultures of spleen cells stimulated by lipopolysaccharide (LPS), IL-2 or LPS + IL-2. We observed that NO synthesis is increased by IFN-γ but inhibited by IFN-α/β. This is not the case when IL-2 is present in the cultures, since interferons play a minor role in the regulation of the NO production. When IL-2 and LPS were associated in the cultures, the IFN-α/β role seems more important than that of IFN-γ. PGE2inhibits NO production in LPS supplemented cultures but has a slight effect in the presence of IL-2 and no effect with IL-2 + LPS. 3-isoButyl-1-methylxanthine (IBMX), an inhibitor of phosphodiesterases, induces a decrease of IFN production. In the presence of H-7, an inhibitor of protein kinase C (PKC), NO production is reduced when the cultures are supplemented by LPS or IL-2 but not when IL-2 and LPS are both added. H-7 also reduced IFN production. In the presence of NG-monomethyl-L-arginine (N-MMA), an inhibitor of NO synthesis, IFN production was increased, with no change in the cytotoxic activity. Hence, interferons regulate NO production by mouse spleen cells and, in return, NO modulates the generation of IFN.


2004 ◽  
Vol 72 (11) ◽  
pp. 6666-6675 ◽  
Author(s):  
Robert E. Brennan ◽  
Kasi Russell ◽  
Guoquan Zhang ◽  
James E. Samuel

ABSTRACT Host control of Coxiella burnetii infections is believed to be mediated primarily by activated monocytes/macrophages. The activation of macrophages by cytokines leads to the production of reactive oxygen intermediates (ROI) and reactive nitrogen intermediates (RNI) that have potent antimicrobial activities. The contributions of ROI and RNI to the inhibition of C. burnetii replication were examined in vitro by the use of murine macrophage-like cell lines and primary mouse macrophages. A gamma interferon (IFN-γ) treatment of infected cell lines and primary macrophages resulted in an increased production of nitric oxide (NO) and hydrogen peroxide (H2O2) and a significant inhibition of C. burnetii replication. The inhibition of replication was reversed in the murine cell line J774.16 upon the addition of either the inducible nitric oxide synthase (iNOS) inhibitor NG-monomethyl-l-arginine (NGMMLA) or the H2O2 scavenger catalase. IFN-γ-treated primary macrophages from iNOS−/− and p47phox−/− mice significantly inhibited replication but were less efficient at controlling infection than IFN-γ-treated wild-type macrophages. To investigate the contributions of ROI and RNI to resistance to infection, we performed in vivo studies, using C57BL/6 wild-type mice and knockout mice lacking iNOS or p47phox. Both iNOS−/− and p47phox−/− mice were attenuated in the ability to control C. burnetii infection compared to wild-type mice. Together, these results strongly support a role for both RNI and ROI in the host control of C. burnetii infection.


1999 ◽  
Vol 66 (6) ◽  
pp. 974-980 ◽  
Author(s):  
Kaoru Tominaga ◽  
Shinji Saito ◽  
Motohiro Matsuura ◽  
Keiji Funatogawa ◽  
Haruo Matsumura ◽  
...  

2010 ◽  
Vol 38 (2) ◽  
pp. 327-330 ◽  
Author(s):  
Pierre Lao-Sirieix ◽  
Rebecca C. Fitzgerald

Most epithelial cancers occur on the background of chronic exposure to damaging agents which is reflected in the long lag phase from development of a pre-invasive lesion to the development of a carcinoma. Luminal refluxate has long been recognized to be associated with Barrett's oesophagus, although causal mechanisms have not been clearly defined. Recently, obesity and dietary nitric oxide have also been implicated in the disease pathogenesis. We have demonstrated that acid can alter cell kinetics and, together with nitric oxide, can induce double-stranded DNA breaks. Aside from exposure to luminal factors, the stromal micro-environment may also be important. There is increasing evidence to suggest that inflammatory pathways such as TGF (transforming growth factor) β may play a role in Barrett's oesophagus carcinogenesis. Hence stromal–epithelial–luminal interactions may influence cell behaviour. As sequelae to this, it is possible that the niches created by the micro-environment may influence genetic epithelial diversity observed within the Barrett's oesophagus segment.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1334-1334
Author(s):  
Seiji Fukuda ◽  
Mariko Abe ◽  
Seiji Yamaguchi ◽  
Louis M. Pelus

Abstract Survivin is a member of the inhibitor of apoptosis protein family that has been implicated in cell cycle control, anti-apoptosis and cell division. Our previous studies and others have shown that Survivin and the cyclin dependent kinase inhibitor p21WAF1/CDKN1 (p21) are functionally associated and are involved in cell cycle, anti-apoptosis and cytokinesis in cancer cells and in normal hematopoietic progenitor cells (HPC). P21 is highly expressed in quiescent hematopoietic stem cells (HSC) in steady state, but the proportion of quiescent HSCs in G0 phase is reduced in p21−/− mice. In contrast, p21 has been shown as positive regulator on cell cycle of normal HPC since p21 deficiency results in fewer total CFU in mouse bone marrow (BM) cells with fewer CFU in S-phase and retrovirus transduction of p21 in p21 deficient bone marrow cells restores total and cycling CFU. We have previously reported that Survivin increases the proliferation of mouse primary HPC and that this enhancing effect is on HPC proliferation is absent when p21 is functionally deleted, suggesting that p21 is required for Survivin to enhance HPC proliferation. In addition, ITD-Flt3 mutations that are normally expressed in patients with acute myeloid leukemia and associate poor prognosis increase expression of both Survivin and p21, implicating their involvement in aberrant proliferation of HPC expressing ITD-Flt3. Herein we have characterized the functional association between p21 and Survivin in normal and transformed cell proliferation. Antagonizing wild-type Survivin in mouse BaF3 cells by retrovirus transduction of a T34A dominant negative mutant Survivin or anti-sense increased p21 expression, even though Survivin requires p21 to enhance HPC proliferation. Ectopic p21 in Survivin+/+ primary mouse bone marrow cells increased the number of immunophenotypically defined c-kit+, lin− (KL) cells, which is consistent with a positive role of p21 in HPC proliferation, however; ectopic expression of p21 failed to increase HPC proliferation in Survivin deficient primary bone marrow cells, suggesting that p21 alone is not sufficient to substitute for Survivin’s enhancing function on normal HPC proliferation. Over-expression of ITD-Flt3 enhanced growth factor independent proliferation of primary mouse marrow c-kit+, Sca-1+, lin− (KSL) cell number; however, co-expression of p21 with ITD-Flt3 dramatically decreased the number of growth factor independent KSL cells (80±6% reduction: P<0.01). Furthermore, the inhibitory effect of p21 on KLS proliferation was further enhanced by Survivin knockout bone marrow cells (64±5% reduction compared with presence of Survivin: P<0.05). These findings indicate that Survivin and p21 have a overlapping but distinct roles in regulating normal HPC proliferation and that manipulating p21 and Survivin may represent a potential therapeutic target for acute leukemia cells expressing ITD-Flt3.


2003 ◽  
Vol 71 (3) ◽  
pp. 1442-1452 ◽  
Author(s):  
Kristin R. Morris ◽  
Ryan D. Lutz ◽  
Hyung-Seok Choi ◽  
Tetsu Kamitani ◽  
Kathryn Chmura ◽  
...  

ABSTRACT Nitric oxide (NO·) produced by inducible nitric oxide synthase (iNOS) is an important host defense molecule against Mycobacterium tuberculosis in mononuclear phagocytes. The objective of this study was to determine the role of the IκBα kinase-nuclear factor κB (IKK-NF-κB) signaling pathway in the induction of iNOS and NO· by a mycobacterial cell wall lipoglycan known as mannose-capped lipoarabinomannan (ManLAM) in mouse macrophages costimulated with gamma interferon (IFN-γ). NF-κB was activated by ManLAM as shown by electrophoretic mobility shift assay, by immunofluorescence of translocated NF-κB in intact cells, and by a reporter gene driven by four NF-κB-binding elements. Transduction of an IκBα mutant (Ser32/36Ala) significantly inhibited NO· expression induced by IFN-γ plus ManLAM. An activated SCF complex, a heterotetramer (Skp1, Cul-1, β-TrCP [F-box protein], and ROC1) involved with ubiquitination, is also required for iNOS-NO· induction. Two NF-κB-binding sites (κBI and κBII) present on the 5′-flanking region of the iNOS promoter bound ManLAM-induced NF-κB similarly. By use of reporter constructs in which one or both sites are mutated, both NF-κB-binding positions were essential in iNOS induction by IFN-γ plus ManLAM. IFN-γ-induced activation of the IRF-1 transcriptional complex is a necessary component in host defense against tuberculosis. Although the 5′-flanking region of the IRF-1 promoter contains an NF-κB-binding site and ManLAM-induced NF-κB also binds to this site, ManLAM was unable to induce IRF-1 expression. The influence of mitogen-activated protein kinases on IFN-γ plus ManLAM induction of iNOS-NO· is not due to any effects on ManLAM induction of NF-κB.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Gabriela Loredana Popa ◽  
Mircea Ioan Popa

Malaria is a serious and, in some unfortunate cases, fatal disease caused by a parasite of the Plasmodium genus. It predominantly occurs in tropical areas where it is transmitted through the bite of an infected Anopheles mosquito. The pathogenesis of malaria is complex and incompletely elucidated. During blood-stage infection, in response to the presence of the parasite, the host’s immune system produces proinflammatory cytokines including IL-6, IL-8, IFN-γ, and TNF, cytokines which play a pivotal role in controlling the growth of the parasite and its elimination. Regulatory cytokines such as transforming growth factor- (TGF-) β and IL-10 maintain the balance between the proinflammatory and anti-inflammatory responses. However, in many cases, cytokines have a double role. On the one hand, they contribute to parasitic clearance, and on the other, they are responsible for pathological changes encountered in malaria. Cytokine-modulating strategies may represent a promising modern approach in disease management. In this review, we discuss the host immune response in malaria, analyzing the latest studies on the roles of pro- and anti-inflammatory cytokines.


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