Glycerol-3-phosphate acyltransferases 3 and 4 direct glycerolipid synthesis and affect functionality in activated macrophages

AbstractMacrophage classical M1 activation via TLR4 triggers a variety of responses to achieve the elimination of foreign pathogens. During this process, there is also an increase in lipid droplets which contain large quantities of triacylglycerol (TAG) and phospholipid (PL). The functional consequences of this increment in lipid mass are poorly understood. Here, we studied the contribution of glycerolipid synthesis to lipid accumulation, focusing specifically on the first and rate-limiting enzyme of the pathway: glycerol-3-phosphate acyltransferase (GPAT). Using bone marrow-derived macrophages (BMDMs) treated with Kdo2-lipid A, we showed that glycerolipid synthesis is induced during macrophage activation. GPAT4 protein level and GPAT3/GPAT4 enzymatic activity increase during this process, and these two isoforms were required for the accumulation of cell TAG and PL. The phagocytic capacity of Gpat3−/− and Gpat4−/− BMDM was impaired. Additionally, inhibiting fatty acid β-oxidation reduced phagocytosis only partially, suggesting that lipid accumulation is not necessary for the energy requirements for phagocytosis. Finally, Gpat4−/− BMDM expressed and released more pro-inflammatory cytokines and chemokines after macrophage activation, suggesting a role for GPAT4 in suppressing inflammatory responses. Together, these results provide evidence that glycerolipid synthesis directed by GPAT4 is important for the attenuation of the inflammatory response in activated macrophages.

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Arginase in Parasitic Infections: Macrophage Activation, Immunosuppression, and Intracellular Signals

Journal of Biomedicine and Biotechnology ◽

10.1155/2010/683485 ◽

2010 ◽

Vol 2010 ◽

pp. 1-10 ◽

Cited By ~ 47

Author(s):

Cinthia C. Stempin ◽

Laura R. Dulgerian ◽

Vanina V. Garrido ◽

Fabio M. Cerban

Keyword(s):

Macrophage Activation ◽

Transforming Growth Factor ◽

Parasite Clearance ◽

Alternative Activation ◽

Parasitic Infections ◽

Activated Macrophages ◽

Proinflammatory Response ◽

Alternatively Activated Macrophages ◽

Arginase 1

A type 1 cytokine-dependent proinflammatory response inducing classically activated macrophages (CaMϕs) is crucial for parasite control during protozoan infections but can also contribute to the development of immunopathological disease symptoms. Type 2 cytokines such as IL-4 and IL-13 antagonize CaMϕs inducing alternatively activated macrophages (AaMϕs) that upregulate arginase-1 expression. During several infections, induction of arginase-1-macrophages was showed to have a detrimental role by limiting CaMϕ-dependent parasite clearance and promoting parasite proliferation. Additionally, the role of arginase-1 in T cell suppression has been explored recently. Arginase-1 can also be induced by IL-10 and transforming growth factor-β(TGF-β) or even directly by parasites or parasite components. Therefore, generation of alternative activation states of macrophages could limit collateral tissue damage because of excessive type 1 inflammation. However, they affect disease outcome by promoting parasite survival and proliferation. Thus, modulation of macrophage activation may be instrumental in allowing parasite persistence and long-term host survival.

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Macrophage activation by monosaccharide precursors of Escherichia coli lipid A.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.82.2.282 ◽

1985 ◽

Vol 82 (2) ◽

pp. 282-286 ◽

Cited By ~ 40

Author(s):

M. Nishijima ◽

F. Amano ◽

Y. Akamatsu ◽

K. Akagawa ◽

T. Tokunaga ◽

...

Keyword(s):

Escherichia Coli ◽

Macrophage Activation ◽

Lipid A

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Poly-L-Lysine Induces Fibrosis on Alginate Microcapsules via the Induction of Cytokines

Cell Transplantation ◽

10.3727/000000001783986800 ◽

2001 ◽

Vol 10 (3) ◽

pp. 263-275 ◽

Cited By ~ 175

Author(s):

Berit L. Strand ◽

Liv Ryan ◽

Peter In't Veld ◽

Bård Kulseng ◽

Anne Mari Rokstad ◽

...

Keyword(s):

Lipid A ◽

Kinase Inhibitor ◽

Inflammatory Responses ◽

Type I Diabetes ◽

Annexin V ◽

Cell Types ◽

P38 Map Kinase ◽

Common Element ◽

Type I ◽

Inflammatory Reactions

Alginate – poly-l-lysine (PLL) microcapsules can be used for transplantation of insulin-producing cells for treatment of type I diabetes. In this work we wanted to study the inflammatory reactions against implanted microcapsules due to PLL. We have seen that by reducing the PLL layer, less overgrowth of the capsule is obtained. By incubating different cell types with PLL and afterwards measuring cell viability with MTT, we found massive cell death at concentrations of PLL higher than 10 μg/ml. Staining with annexin V and propidium iodide showed that PLL induced necrosis but not apoptosis. The proinflammatory cytokine, tumor necrosis factor (TNF), was detected in supernatants from monocytes stimulated with PLL. The TNF response was partly inhibited with antibodies against CD14, which is a well-known receptor for lipopolysaccharide (LPS). Bactericidal permeability increasing protein (BPI) and a lipid A analogue (B-975), which both inhibit LPS, did not inhibit PLL from stimulating monocytes to TNF production. This indicates that PLL and LPS bind to different sites on monocytes, but because they both are inhibited by a p38 MAP kinase inhibitor, they seem to have a common element in the signal transducing pathway. These results suggest that PLL may provoke inflammatory responses either directly or indirectly through its necrosis-inducing abilities. By combining soluble PLL and alginate both the toxic and TNF-inducing effects of PLL were reduced. The implications of these data are to use alginate microcapsules with low amounts of PLL for transplantation purposes.

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Abstract 153: IL-10 Accelerates Re-Endothelialization and Inhibits Post-injury Intimal Hyperplasia following Carotid Artery Denudation by Attenuating TNF-alpha-induced Endothelial Cell Dysfunction

Circulation Research ◽

10.1161/res.115.suppl_1.153 ◽

2014 ◽

Vol 115 (suppl_1) ◽

Author(s):

Suresh K Verma ◽

Prasanna Krishnamurthy ◽

Alexander R Mackie ◽

Erin E Vaughan ◽

Mohsin Khan ◽

...

Keyword(s):

Endothelial Cell ◽

Inflammatory Responses ◽

Thrombus Formation ◽

Specific Effect ◽

Mononuclear Phagocytes ◽

Tnf Alpha ◽

Post Injury ◽

Knock Out ◽

Cytokines And Chemokines

The association of inflammation with atherosclerosis and restenosis is now fairly well established. Restenosis, a persistent complication of percutaneous vascular interventions, is thought to be a complex response to injury, which includes early thrombus formation, neointimal growth and acute inflammation. Mononuclear phagocytes are likely participants in the host response to vascular injury, via the secretion of cytokines and chemokines, including TNF-alpha (TNF). Others and we have previously shown that IL-10 inhibits TNF and other inflammatory mediators produced in response to cardiovascular injuries. The specific effect of IL-10 on endothelial cell (EC) biology is not well elucidated. Here we report that in a mouse model of carotid denudation, IL-10 knock-out mice (IL10KO) displayed significantly delayed ReEndothelialization and enhanced neointimal growth compared to their WT counterparts. Exogenous treatment of recombinant IL-10 dramatically blunted the inflammatory cell infiltration and neointimal thickening while significantly accelerating the recovery of the injured endothelium both WT and IL10KO mice. In vitro, IL10 co-treatment reversed TNF-mediated growth arrest, EC cell cycle inhibition, EC-monocyte adhesion and EC apoptosis. At signaling level, IL-10 reduced TNF-induced activation of JNK MAP kinase while simultaneously activating PI3K/Akt pathway. Because IL-10 function and signaling are important components for control of inflammatory responses, these results may provide insights necessary to develop strategies for modulating vascular repair and other accelerated arteriopathies, including transplant vasculopathy and vein graft hyperplasia.

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Lipid accumulation by migrating monarch butterflies (Danaus plexippus L.)

Canadian Journal of Zoology ◽

10.1139/z93-012 ◽

1993 ◽

Vol 71 (1) ◽

pp. 76-82 ◽

Cited By ~ 22

Author(s):

David L. Gibo ◽

Jody A. McCurdy

Keyword(s):

Lipid Accumulation ◽

Seasonal Changes ◽

Late Phase ◽

Danaus Plexippus ◽

Late Summer ◽

Dry Mass ◽

Middle Phase ◽

Southern Ontario ◽

Lipid Mass ◽

Peak Abundance

The migration of Danaus plexippus during the late summer in southern Ontario in 1986 lasted for about 8 weeks and consisted of three phases, an early phase characterized by increasing abundance, a middle phase of peak abundance, and a late phase characterized by declining abundance. As the season progressed, systematic changes were observed in wet mass, dry mass, lean dry mass, lipid mass, and forewing length. Wet mass, lean dry mass, and forewing length were similar for early- and middle-phase individuals, but declined in late-phase migrants. Lipid mass peaked in the middle phase of the migration and then declined abruptly in the late phase. Dry mass also peaked in the middle phase, reflecting changes in lipid mass and lean dry mass. We hypothesize that the observed changes in lipid mass and lean dry mass over the 8 weeks resulted from changes in population structure as well as seasonal changes in the weather, and in availability of nectar. Opposing conclusions reached in previous studies of lipid accumulation in D. plexippus are probably the result of failure to control for phase of migration.

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Proinflammatory responses in SARS-CoV-2 infected and soluble spike glycoprotein S1 subunit activated human macrophages

10.1101/2021.06.14.448426 ◽

2021 ◽

Author(s):

Kim Chiok ◽

Kevin Hutchison ◽

Lindsay Grace Miller ◽

Santanu Bose ◽

Tanya A Miura

Keyword(s):

Virus Infection ◽

Inflammatory Response ◽

Virus Replication ◽

Inflammatory Mediators ◽

Inflammatory Responses ◽

Activated Macrophages ◽

Human Macrophages ◽

Tnf Α ◽

Proinflammatory Responses

Critically ill COVID-19 patients infected with SARS-CoV-2 display signs of generalized hyperinflammation. Macrophages trigger inflammation to eliminate pathogens and repair tissue, but this process can also lead to hyperinflammation and resulting exaggerated disease. The role of macrophages in dysregulated inflammation during SARS-CoV-2 infection is poorly understood. We used SARS-CoV-2 infected and glycosylated soluble SARS-CoV-2 Spike S1 subunit (S1) treated THP-1 human-derived macrophage-like cell line to clarify the role of macrophages in pro-inflammatory responses. Soluble S1 upregulated TNF-α and CXCL10 mRNAs, and induced secretion of TNF-α from THP-1 macrophages. While THP-1 macrophages did not support productive SARS-CoV-2 replication, virus infection resulted in upregulation of both TNF-α and CXCL10 genes. Our study shows that S1 is a key viral component inducing inflammatory response in macrophages, independently of virus replication. Thus, virus-infected or soluble S1-activated macrophages may become sources of pro-inflammatory mediators contributing to hyperinflammation in COVID-19 patients.

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Human genetic deficiencies reveal the roles of complement in the inflammatory network: Lessons from nature

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0903613106 ◽

2009 ◽

Vol 106 (37) ◽

pp. 15861-15866 ◽

Cited By ~ 93

Author(s):

Knut Tore Lappegård ◽

Dorte Christiansen ◽

Anne Pharo ◽

Ebbe Billmann Thorgersen ◽

Bernt Christian Hellerud ◽

...

Keyword(s):

Inflammatory Responses ◽

Gram Negative Bacteria ◽

Enzyme Release ◽

Experimental Conditions ◽

Gram Negative ◽

Cytokines And Chemokines ◽

Ifn Γ ◽

Inducible Protein ◽

The Complement System

Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, its involvement in human inflammation is incompletely understood. The responses to Gram-negative bacteria were here studied taking advantage of human genetic complement-deficiencies—nature's own knockouts—including a previously undescribed C5 defect. Such deficiencies provide a unique tool for investigating the biological role of proteins. The experimental conditions allowed cross-talk between the different inflammatory pathways using a whole blood model based on the anticoagulant lepirudin, which does not interfere with the complement system. Expression of tissue factor, cell adhesion molecules, and oxidative burst depended highly on C5, mediated through the activation product C5a, whereas granulocyte enzyme release relied mainly on C3 and was C5a-independent. Release of cytokines and chemokines was mediated to varying degrees by complement and CD14; for example, interleukin (IL)-1β and IL-8 were more dependent on complement than IFN-γ and IL-6, which were highly dependent on CD14. IL-1 receptor antagonist (IL-1ra) and IFN-γ inducible protein 10 (IP-10) were fully dependent on CD14 and inversely regulated by complement, that is, complement deficiency and complement inhibition enhanced their release. Granulocyte responses were mainly complement-dependent, whereas monocyte responses were more dependent on CD14. Notably, all responses were abolished by combined neutralization of complement and CD14. The present study provides important insight into the comprehensive role of complement in human inflammatory responses to Gram-negative bacteria.

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HaCaT Cells as a Reliable In Vitro Differentiation Model to Dissect the Inflammatory/Repair Response of Human Keratinocytes

Mediators of Inflammation ◽

10.1155/2017/7435621 ◽

2017 ◽

Vol 2017 ◽

pp. 1-12 ◽

Cited By ~ 43

Author(s):

Irma Colombo ◽

Enrico Sangiovanni ◽

Roberta Maggio ◽

Carlo Mattozzi ◽

Stefania Zava ◽

...

Keyword(s):

Cell Density ◽

Skin Diseases ◽

Inflammatory Responses ◽

Human Keratinocytes ◽

Suitable Model ◽

Hacat Cells ◽

Primary Human Keratinocytes ◽

Proinflammatory Mediators ◽

Cytokines And Chemokines

Cultured primary human keratinocytes are frequently employed for studies of immunological and inflammatory responses; however, interpretation of experimental data may be complicated by donor to donor variability, the relatively short culture lifetime, and variations between passages. To standardize the in vitro studies on keratinocytes, we investigated the use of HaCaT cells, a long-lived, spontaneously immortalized human keratinocyte line which is able to differentiate in vitro, as a suitable model to follow the release of inflammatory and repair mediators in response to TNFα or IL-1β. Different treatment conditions (presence or absence of serum) and differentiation stimuli (increase in cell density as a function of time in culture and elevation of extracellular calcium) were considered. ELISA and Multiplex measurement technologies were used to monitor the production of cytokines and chemokines. Taken together, the results highlight that Ca2+ concentration in the medium, cell density, and presence of serum influences at different levels the release of proinflammatory mediators by HaCaT cells. Moreover, HaCaT cells maintained in low Ca2+ medium and 80% confluent are similar to normal keratinocytes in terms of cytokine production suggesting that HaCaT cells may be a useful model to investigate anti-inflammatory interventions/therapies on skin diseases.

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An Autocrine Wnt5a Loop Promotes NF-κB Pathway Activation and Cytokine/Chemokine Secretion in Melanoma

Cells ◽

10.3390/cells8091060 ◽

2019 ◽

Vol 8 (9) ◽

pp. 1060 ◽

Cited By ~ 8

Author(s):

Gastón Barbero ◽

María Victoria Castro ◽

María Belén Villanueva ◽

María Josefina Quezada ◽

Natalia Brenda Fernández ◽

...

Keyword(s):

Nuclear Translocation ◽

Epithelial Mesenchymal Transition ◽

Inflammatory Responses ◽

Inflammatory Diseases ◽

Melanoma Cells ◽

Dominant Negative ◽

Migration And Invasion ◽

Soluble Receptor ◽

Mesenchymal Transition ◽

Cytokines And Chemokines

Wnt5a signaling has been implicated in the progression of cancer by regulating multiple cellular processes, largely migration and invasion, epithelial-mesenchymal transition (EMT), and metastasis. Since Wnt5a signaling has also been involved in inflammatory processes in infectious and inflammatory diseases, we addressed the role of Wnt5a in regulating NF-κB, a pivotal mediator of inflammatory responses, in the context of cancer. The treatment of melanoma cells with Wnt5a induced phosphorylation of the NF-κB subunit p65 as well as IKK phosphorylation and IκB degradation. By using cDNA overexpression, RNA interference, and dominant negative mutants we determined that ROR1, Dvl2, and Akt (from the Wnt5a pathway) and TRAF2 and RIP (from the NF-κB pathway) are required for the Wnt5a/NF-κB crosstalk. Wnt5a also induced p65 nuclear translocation and increased NF-κB activity as evidenced by reporter assays and a NF-κB-specific upregulation of RelB, Bcl-2, and Cyclin D1. Further, stimulation of melanoma cells with Wnt5a increased the secretion of cytokines and chemokines, including IL-6, IL-8, IL-11, and IL-6 soluble receptor, MCP-1, and TNF soluble receptor I. The inhibition of endogenous Wnt5a demonstrated that an autocrine Wnt5a loop is a major regulator of the NF-κB pathway in melanoma. Taken together, these results indicate that Wnt5a activates the NF-κB pathway and has an immunomodulatory effect on melanoma through the secretion of cytokines and chemokines.

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Deriving a Boolean dynamics to reveal macrophage activation with in vitro temporal cytokine expression profiles

BMC Bioinformatics ◽

10.1186/s12859-019-3304-5 ◽

2019 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Ricardo Ramirez ◽

Allen Michael Herrera ◽

Joshua Ramirez ◽

Chunjiang Qian ◽

David W. Melton ◽

...

Keyword(s):

Boolean Network ◽

Macrophage Activation ◽

Expression Profiles ◽

Network Models ◽

Cytokine Expression ◽

Boolean Networks ◽

Experimental Results ◽

Activated Macrophages ◽

Activation Patterns

Abstract Background Macrophages show versatile functions in innate immunity, infectious diseases, and progression of cancers and cardiovascular diseases. These versatile functions of macrophages are conducted by different macrophage phenotypes classified as classically activated macrophages and alternatively activated macrophages due to different stimuli in the complex in vivo cytokine environment. Dissecting the regulation of macrophage activations will have a significant impact on disease progression and therapeutic strategy. Mathematical modeling of macrophage activation can improve the understanding of this biological process through quantitative analysis and provide guidance to facilitate future experimental design. However, few results have been reported for a complete model of macrophage activation patterns. Results We globally searched and reviewed literature for macrophage activation from PubMed databases and screened the published experimental results. Temporal in vitro macrophage cytokine expression profiles from published results were selected to establish Boolean network models for macrophage activation patterns in response to three different stimuli. A combination of modeling methods including clustering, binarization, linear programming (LP), Boolean function determination, and semi-tensor product was applied to establish Boolean networks to quantify three macrophage activation patterns. The structure of the networks was confirmed based on protein-protein-interaction databases, pathway databases, and published experimental results. Computational predictions of the network evolution were compared against real experimental results to validate the effectiveness of the Boolean network models. Conclusion Three macrophage activation core evolution maps were established based on the Boolean networks using Matlab. Cytokine signatures of macrophage activation patterns were identified, providing a possible determination of macrophage activations using extracellular cytokine measurements.

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