Adipose tissue is a major source of interleukin-1 receptor antagonist: upregulation in obesity and inflammation.
The secreted form of the interleukin-1 receptor antagonist (IL-1Ra) is an acute-phase protein intervening in the counterregulation of inflammatory processes. We previously showed that this cytokine antagonist is upregulated in the serum of obese patients, correlating with BMI and insulin resistance. In this study, we examined the expression pattern of IL-1Ra and showed that it is highly expressed not only in liver and spleen, but also in white adipose tissue (WAT), where it is upregulated in obesity. In WAT of obese humans, IL-1Ra was also markedly increased. Moreover, human WAT explants secreted IL-1Ra into the medium, a process that could be stimulated fivefold by interferon-beta. Finally, lipopolysaccharide administration induced a long-lasting expression of IL-1Ra in mouse WAT, suggesting that adipose tissue is an important source of IL-1Ra in both obesity and inflammation. In summary, we demonstrated that WAT is one of the most important sources of IL-1Ra quantitatively, suggesting that this tissue could represent a novel target for anti-inflammatory treatment. Moreover, it can be speculated that IL-1Ra, whose production is markedly increased in WAT in obese individuals, contributes further to weight gain because of its endocrine and paracrine effects on the hypothalamus and adipocytes, respectively.
Juge-Aubry
Cristiana E
CE
Endocrine Unit, Division of Endocrinology, Diabetes and Nutrition, Department of Internal Medicine, University Hospital Geneva, 24 rue Micheli-du-Crest, CH-1211 Geneva 14, Switzerland.
Somm
Emmanuel
E
Giusti
Vittorio
V
Pernin
Agnès
A
Chicheportiche
Rachel
R
Verdumo
Chantal
C
Rohner-Jeanrenaud
Françoise
F
Burger
Danielle
D
Dayer
Jean-Michel
JM
Meier
Christoph A
CA
D000273:Adipose Tissue / Q000187:drug effects / Q000503:physiopathology*; D000818:Animals; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation / Q000235:genetics / Q000276:immunology; D016899:Interferon-beta / Q000494:pharmacology; D053590:Interleukin 1 Receptor Antagonist Protein; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D009765:Obesity / Q000235:genetics / Q000276:immunology*; D009924:Organ Culture Techniques; D012333:RNA, Messenger / Q000235:genetics; D012016:Reference Values; D012795:Sialoglycoproteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000502:physiology
C507763:IL1RN protein, human; C507764:Il1rn protein, mouse; D053590:Interleukin 1 Receptor Antagonist Protein; D012333:RNA, Messenger; D012795:Sialoglycoproteins; D014409:Tumor Necrosis Factor-alpha; D016899:Interferon-beta