title: Activation of invariant natural killer T cells by lipid excess promotes tissue inflammation, insulin resistance, and hepatic steatosis in obese mice.
abstract: Obesity triggers a low-grade systemic inflammation, which plays an important role in the development of obesity-associated metabolic diseases. In searching for links between lipid accumulation and chronic inflammation, we examined invariant natural killer T (iNKT) cells, a subset of T lymphocytes that react with lipids and regulate inflammatory responses. We show that iNKT cells respond to dietary lipid excess and become activated before or at the time of tissue recruitment of inflammatory leukocytes, and that these cells progressively increase proinflammatory cytokine production in obese mice. Such iNKT cells skew other leukocytes toward proinflammatory cytokine production and induce an imbalanced proinflammatory cytokine environment in multiple tissues. Further, iNKT cell deficiency ameliorates tissue inflammation and provides protection against obesity-induced insulin resistance and hepatic steatosis. Conversely, chronic iNKT cell stimulation using a canonical iNKT cell agonist exacerbates tissue inflammation and obesity-associated metabolic disease. These findings place iNKT cells into the complex network linking lipid excess to inflammation in obesity and suggest new therapeutic avenues for obesity-associated metabolic disorders.
authors.affiliation: Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA. lan.wu@vanderbilt.edu
authors.forename: Lan
authors.initials: L
authors.lastname: Wu
authors.forename: Vrajesh V
authors.initials: VV
authors.lastname: Parekh
authors.forename: Curtis L
authors.initials: CL
authors.lastname: Gabriel
authors.forename: Deanna P
authors.initials: DP
authors.lastname: Bracy
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Marks-Shulman
authors.forename: Robyn A
authors.initials: RA
authors.lastname: Tamboli
authors.forename: Sungjune
authors.initials: S
authors.lastname: Kim
authors.forename: Yanice V
authors.initials: YV
authors.lastname: Mendez-Fernandez
authors.forename: Gurdyal S
authors.initials: GS
authors.lastname: Besra
authors.forename: Jefferson P
authors.initials: JP
authors.lastname: Lomenick
authors.forename: Brandon
authors.initials: B
authors.lastname: Williams
authors.forename: David H
authors.initials: DH
authors.lastname: Wasserman
authors.forename: Luc
authors.initials: L
authors.lastname: Van Kaer
mesh_terms: D052436:Adipose Tissue, White / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D000818:Animals; D055610:Antigens, CD1d / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D004041:Dietary Fats / Q000008:administration & dosage / Q000276:immunology; D005234:Fatty Liver / Q000235:genetics / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D005699:Galactosylceramides / Q000008:administration & dosage / Q000276:immunology / Q000502:physiology*; D007249:Inflammation / Q000235:genetics / Q000276:immunology*; D018836:Inflammation Mediators / Q000276:immunology / Q000378:metabolism; D007333:Insulin Resistance / Q000235:genetics / Q000276:immunology*; D008055:Lipids / Q000008:administration & dosage / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D055611:Natural Killer T-Cells / Q000276:immunology* / Q000378:metabolism; D009765:Obesity / Q000235:genetics / Q000276:immunology*
chemical_list: D055610:Antigens, CD1d; D016207:Cytokines; D004041:Dietary Fats; D005699:Galactosylceramides; D018836:Inflammation Mediators; D008055:Lipids; C493154:alpha-galactosylceramide