MAPK–PPARα/γ signal transduction pathways are involved in Chlamydia pneumoniae-induced macrophage-derived foam cell formation

2014 ◽  
Vol 69-70 ◽  
pp. 1-8 ◽  
Author(s):  
Bei Cheng ◽  
Xiaohua Wu ◽  
Shan Sun ◽  
Qinqin Wu ◽  
Chunli Mei ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Chlamydia Pneumoniae ◽  
Foam Cell ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
Signal Transduction Pathways

scholarly journals Chlamydia pneumoniae-Induced Foam Cell Formation Requires MyD88-Dependent and -Independent Signaling and Is Reciprocally Modulated by Liver X Receptor Activation

2008 ◽  
Vol 181 (10) ◽  
pp. 7186-7193 ◽  
Author(s):  
Shuang Chen ◽  
Rosalinda Sorrentino ◽  
Kenichi Shimada ◽  
Yonca Bulut ◽  
Terence M. Doherty ◽  
...  
Keyword(s):  
Chlamydia Pneumoniae ◽  
Foam Cell ◽  
Cell Formation ◽  
Receptor Activation ◽  
Liver X Receptor ◽  
Foam Cell Formation

Abstract 168: The Acceleration of Foam Cell Formation by Chlamydia Pneumoniae Requires Nlrp3 Inflammasome Activation and Il-1 Signaling

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Gantsetseg Tumurkhuu ◽  
Jargalsaikhan Dagvadorj ◽  
Timothy R Crother ◽  
Kenichi Shimada ◽  
Moshe Arditi ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Cholesterol Efflux ◽  
Molecular Mechanisms ◽  
Chlamydia Pneumoniae ◽  
Foam Cell ◽  
Cell Formation ◽  
Peritoneal Macrophages ◽  
Foam Cell Formation ◽  
Inflammasome Activation ◽  
Abca1 Expression

Background & Objective: Foam cell formation (FCF) due to excessive accumulation of cholesterol by macrophages is a pathological hallmark of atherosclerosis. Chlamydia pneumoniae (Cp) promotes FCF in the presence of oxLDL, but the exact molecular mechanisms are still not completely delineated. Recent data indicates that the Nlrp3 inflammasome plays an important role in the formation of atherosclerotic plaques. Here we investigated the role of the Nlrp3 inflammasome during the acceleration of FCF by Cp infection. Methods and Results: In order to determine if the NLRP3 inflammasome played a role in Cp infection induced acceleration of FCF, we treated resident peritoneal macrophages exposed to oxLDL and Cp with the IL-1R antagonist, Anakinra, to block IL-1 signaling. Treatment with Anakinra resulted in a significant reduction in FCF. Nlrp3-/-, Casp1-/-, and WT macrophages were also treated with live Cp in the presence or absence of oxLDL. We found that Nlrp3-/- and Casp1-/- macrophages had significantly less FCF compared with WT cells. Interestingly, both ABCA1 (cholesterol efflux transporter) and its transcription factor, liver X receptor (LXR-α), were increased in Nlrp3-/- and Casp1-/- macrophages compared with WT cells. Addition of rIL-1β to Nlrp3-/- macrophages led to a decrease in ABCA1 expression and greater FCF. Importantly, Il1r-/- macrophages also had greater ABCA1 expression and reduced FCF when exposed to oxLDL and Cp infection. Conclusion: These data suggest that Cp infection facilitates foam cell formation in the presence of oxLDL by producing NLRP3 dependent IL-1 cytokines, which then feed back on the macrophages and interferes with cholesterol efflux by negatively regulating ABCA1. In the absence of IL-1 signaling, the expression of ABCA1 is upregulated leading to greater cholesterol efflux and reduced FCF. Thus we have identified a novel regulatory loop controlling FCF. Understanding these interacting pathways will lead to new therapeutic strategies against atherosclerosis.

scholarly journals Chlamydia pneumoniae Hijacks a Host Autoregulatory IL-1β Loop to Drive Foam Cell Formation and Accelerate Atherosclerosis

2018 ◽  
Vol 28 (3) ◽  
pp. 432-448.e4 ◽  
Author(s):  
Gantsetseg Tumurkhuu ◽  
Jargalsaikhan Dagvadorj ◽  
Rebecca A. Porritt ◽  
Timothy R. Crother ◽  
Kenichi Shimada ◽  
...  
Keyword(s):  
Chlamydia Pneumoniae ◽  
Foam Cell ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
Accelerate Atherosclerosis

scholarly journals Koala Biovar of Chlamydia pneumoniae Infects Human and Koala Monocytes and Induces Increased Uptake of Lipids In Vitro

2001 ◽  
Vol 69 (12) ◽  
pp. 7894-7897 ◽  
Author(s):  
Katie A. Coles ◽  
Peter Timms ◽  
David W. Smith
Keyword(s):  
Chlamydia Pneumoniae ◽  
Foam Cell ◽  
Low Density Lipoprotein ◽  
Cell Formation ◽  
Density Lipoprotein ◽  
Foam Cells ◽  
Foam Cell Formation ◽  
Low Density ◽  
Human Monocytes

ABSTRACT We examined the ability of the koala biovar of Chlamydia pneumoniae to infect both Hep-2 cells and human monocytes and the effect of infection on the formation of foam cells. The koala biovar produced large inclusions in both human and koala monocytes and in Hep-2 cells. Koala C. pneumoniae induced foam cell formation with and without added low-density lipoprotein, in contrast to TW183, which produced increased foam cell formation only in the presence of low-density lipoprotein.

scholarly journals A Chlamydia pneumoniae Component That Induces Macrophage Foam Cell Formation Is Chlamydial Lipopolysaccharide

1998 ◽  
Vol 66 (11) ◽  
pp. 5067-5072 ◽  
Author(s):  
Murat V. Kalayoglu ◽  
Gerald I. Byrne
Keyword(s):  
Cholesteryl Ester ◽  
Chlamydia Pneumoniae ◽  
Elevated Temperatures ◽  
Foam Cell ◽  
Cell Formation ◽  
Disease Process ◽  
Foam Cell Formation ◽  
Human Macrophage ◽  
Macrophage Foam Cell ◽  
Cholesteryl Ester Accumulation

ABSTRACT Chlamydia pneumoniae infection is associated with atherosclerotic heart and vessel disease, but a causal relationship between this pathogen and the disease process has not been established. Recently, it was reported that C. pneumoniae induces human macrophage foam cell formation, a key event in early atheroma development, suggesting a role for the organism in atherogenesis. This study further examines C. pneumoniae-induced foam cell formation in the murine macrophage cell line RAW-264.7. Infected RAW cells accumulated cholesteryl esters when cultured in the presence of low-density lipoprotein in a manner similar to that described for human macrophages. Exposure of C. pneumoniae elementary bodies to periodate, but not elevated temperatures, inhibited cholesteryl ester accumulation, suggesting a role for chlamydial lipopolysaccharide (cLPS) in macrophage foam cell formation. Purified cLPS was found to be sufficient to induce cholesteryl ester accumulation and foam cell formation. Furthermore, the LPS antagonist lipid X inhibited C. pneumoniae and cLPS-induced lipid uptake. These data indicate that cLPS is a C. pneumoniae component that induces macrophage foam cell formation and suggest that infected macrophages chronically exposed to cLPS may accumulate excess cholesterol to contribute to atheroma development.

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