Blockade of T cell contact-activation of human monocytes by high-density lipoproteins reveals a new pattern of cytokine and inflammatory genes.
BACKGROUND
Cellular contact with stimulated T cells is a potent inducer of cytokine production in human monocytes and is likely to play a substantial part in chronic/sterile inflammatory diseases. High-density lipoproteins (HDL) specifically inhibit the production of pro-inflammatory cytokines induced by T cell contact.


RESULTS
To further elucidate the pro-inflammatory functions of cellular contact with stimulated T cells and its inhibition by HDL, we carried out multiplex and microarray analyses. Multiplex analysis of monocyte supernatant revealed that 12 out of 27 cytokines were induced upon contact with stimulated T cells, which cytokines included IL-1Ra, G-CSF, GM-CSF, IFNgamma, CCL2, CCL5, TNF, IL-1beta, IL-6, IL-8, CCL3, and CCL4, but only the latter six were inhibited by HDL. Microarray analysis showed that 437 out of 54,675 probe sets were enhanced in monocytes activated by contact with stimulated T cells, 164 probe sets (i.e., 38%) being inhibited by HDL. These results were validated by qPCR. Interestingly, the cytokines induced by T cell contact in monocytes comprised IL-1beta, IL-6 but not IL-12, suggesting that this mechanism might favor Th17 polarization, which emphasizes the relevance of this mechanism to chronic inflammatory diseases and highlights the contrast with acute inflammatory conditions that usually involve lipopolysaccharides (LPS). In addition, the expression of miR-155 and production of prostaglandin E(2)-both involved in inflammatory response-were triggered by T cell contact and inhibited in the presence of HDL.


CONCLUSIONS
These results leave no doubt as to the pro-inflammatory nature of T cell contact-activation of human monocytes and the anti-inflammatory functions of HDL.
Gruaz
Lyssia
L
Division of Immunology and Allergy, Inflammation and Allergy Research Group, Hans Wilsdorf Laboratory, Department of Internal Medicine and Faculty of Medicine, University of Geneva, Geneva, Switzerland.
Delucinge-Vivier
Céline
C
Descombes
Patrick
P
Dayer
Jean-Michel
JM
Burger
Danielle
D
D045744:Cell Line, Tumor; D002478:Cells, Cultured; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D020869:Gene Expression Profiling; D006801:Humans; D007249:Inflammation / Q000235:genetics / Q000276:immunology; D053583:Interleukin-1beta / Q000235:genetics / Q000378:metabolism; D008075:Lipoproteins, HDL / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000276:immunology; D035683:MicroRNAs / Q000235:genetics; D009000:Monocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000276:immunology
D016207:Cytokines; D053583:Interleukin-1beta; D008075:Lipoproteins, HDL; C524942:MIRN155 microRNA, human; D035683:MicroRNAs; D015232:Dinoprostone