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Fabrizi M, Marchetti V, Mavilio M, Marino A, Casagrande V, Cavalera M, Moreno-Navarrete JM, Mezza T, Sorice GP, Fiorentino L, Menghini R, Lauro R, Monteleone G, Giaccari A, Fernandez Real JM, Federici M. IL-21 is a major negative regulator of IRF4-dependent lipolysis affecting Tregs in adipose tissue and systemic insulin sensitivity. Diabetes 2014; 63:2086-96. [PMID: 24430438 DOI: 10.2337/db13-0939] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Obesity elicits immune cell infiltration of adipose tissue provoking chronic low-grade inflammation. Regulatory T cells (Tregs) are specifically reduced in adipose tissue of obese animals. Since interleukin (IL)-21 plays an important role in inducing and maintaining immune-mediated chronic inflammatory processes and negatively regulates Treg differentiation/activity, we hypothesized that it could play a role in obesity-induced insulin resistance. We found IL-21 and IL-21R mRNA expression upregulated in adipose tissue of high-fat diet (HFD) wild-type (WT) mice and in stromal vascular fraction from human obese subjects in parallel to macrophage and inflammatory markers. Interestingly, a larger infiltration of Treg cells was seen in the adipose tissue of IL-21 knockout (KO) mice compared with WT animals fed both normal diet and HFD. In a context of diet-induced obesity, IL-21 KO mice, compared with WT animals, exhibited lower body weight, improved insulin sensitivity, and decreased adipose and hepatic inflammation. This metabolic phenotype is accompanied by a higher induction of interferon regulatory factor 4 (IRF4), a transcriptional regulator of fasting lipolysis in adipose tissue. Our data suggest that IL-21 exerts negative regulation on IRF4 and Treg activity, developing and maintaining adipose tissue inflammation in the obesity state.
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Affiliation(s)
- Marta Fabrizi
- Department of Systems Medicine, University of Rome "Tor Vergata," Rome, Italy
| | - Valentina Marchetti
- Department of Systems Medicine, University of Rome "Tor Vergata," Rome, Italy
| | - Maria Mavilio
- Department of Systems Medicine, University of Rome "Tor Vergata," Rome, Italy
| | - Arianna Marino
- Department of Systems Medicine, University of Rome "Tor Vergata," Rome, Italy
| | - Viviana Casagrande
- Department of Systems Medicine, University of Rome "Tor Vergata," Rome, Italy
| | - Michele Cavalera
- Department of Systems Medicine, University of Rome "Tor Vergata," Rome, Italy
| | - Josè Maria Moreno-Navarrete
- University Department of Diabetes, Endocrinology and Nutrition, University Hospital of Girona "Dr. Josep Trueta," Institut d'Investigació Biomédica de Girona IdibGi, and CIBER Fisiopatología de la Obesidad y Nutrición, Girona, Spain
| | - Teresa Mezza
- Division of Endocrinology and Metabolic Diseases, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Gian Pio Sorice
- Division of Endocrinology and Metabolic Diseases, Università Cattolica del Sacro Cuore, Rome, ItalyDiabetic Care Clinics, Associazione dei Cavalieri Italiani del Sovrano Militare Ordine di Malta (ACI SMOM), Rome, Italy
| | - Loredana Fiorentino
- Department of Systems Medicine, University of Rome "Tor Vergata," Rome, Italy
| | - Rossella Menghini
- Department of Systems Medicine, University of Rome "Tor Vergata," Rome, Italy
| | - Renato Lauro
- Department of Systems Medicine, University of Rome "Tor Vergata," Rome, Italy
| | - Giovanni Monteleone
- Department of Systems Medicine, University of Rome "Tor Vergata," Rome, Italy
| | - Andrea Giaccari
- Division of Endocrinology and Metabolic Diseases, Università Cattolica del Sacro Cuore, Rome, ItalyFondazione Don Gnocchi, Milan, Italy
| | - José Manuel Fernandez Real
- University Department of Diabetes, Endocrinology and Nutrition, University Hospital of Girona "Dr. Josep Trueta," Institut d'Investigació Biomédica de Girona IdibGi, and CIBER Fisiopatología de la Obesidad y Nutrición, Girona, Spain
| | - Massimo Federici
- Department of Systems Medicine, University of Rome "Tor Vergata," Rome, ItalyCenter for Atherosclerosis, Department of Medicine, Policlinico Tor Vergata, Rome, Italy
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