title: Three-dimensional spheroid cell model of in vitro adipocyte inflammation.
abstract: To improve treatment of obesity, a contributing factor to multiple systemic and metabolic diseases, a better understanding of metabolic state and environmental stress at the cellular level is essential. This work presents development of a three-dimensional (3D) in vitro model of adipose tissue displaying induced lipid accumulation as a function of fatty acid supplementation that, subsequently, investigates cellular responses to a pro-inflammatory stimulus, thereby recapitulating key stages of obesity progression. Three-dimensional spheroid organization of adipose cells was induced by culturing 3T3-L1 mouse preadipocytes on an elastin-like polypeptide-polyethyleneimine (ELP-PEI)-coated surface. Results indicate a more differentiated phenotype in 3D spheroid cultures relative to two-dimensional (2D) monolayer analogues based on triglyceride accumulation, CD36 and CD40 protein expression, and peroxisome proliferator-activated receptor-γ (PPAR-γ) and adiponectin mRNA expression. The 3T3-L1 adipocyte spheroid model was then used to test the effects of a pro-inflammatory microenvironment, namely maturation in the presence of elevated fatty acid levels followed by acute exposure to tumor necrosis factor alpha (TNF-α). Under these conditions, we demonstrate that metabolic function was reduced across all cultures exposed to TNF-α, especially so when pre-exposed to linoleic acid. Further, in response to TNF-α, enhanced lipolysis, monitored as increased extracellular glycerol and fatty acids levels, was observed in adipocytes cultured in the presence of exogenous fatty acids. Taken together, our 3D spheroid model showed enhanced adipogenic differentiation and presents a platform for elucidating the key phenotypic responses that occur in pro-inflammatory microenvironments that characterize obesogenic states.
authors.affiliation: 1Department of Biomedical Materials Science, School of Dentistry, University of Mississippi Medical Center, Jackson, Mississippi.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Turner
authors.affiliation: 2Life Sciences Institute, University of Michigan, Ann Arbor, Michigan.
authors.forename: Yi
authors.initials: Y
authors.lastname: Tang
authors.affiliation: 2Life Sciences Institute, University of Michigan, Ann Arbor, Michigan.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Weiss
authors.affiliation: 1Department of Biomedical Materials Science, School of Dentistry, University of Mississippi Medical Center, Jackson, Mississippi.
authors.forename: Amol V
authors.initials: AV
authors.lastname: Janorkar
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D050156:Adipogenesis / Q000187:drug effects; D052242:Adiponectin / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D018955:CD36 Antigens / Q000096:biosynthesis / Q000235:genetics; D019013:CD40 Antigens / Q000096:biosynthesis / Q000235:genetics; D018929:Cell Culture Techniques; D060833:Cellular Microenvironment; D004041:Dietary Fats / Q000494:pharmacology; D005227:Fatty Acids / Q000494:pharmacology; D005990:Glycerol / Q000378:metabolism; D066298:In Vitro Techniques; D007249:Inflammation / Q000378:metabolism / Q000473:pathology*; D019787:Linoleic Acid / Q000494:pharmacology; D008066:Lipolysis; D051379:Mice; D009765:Obesity; D047495:PPAR gamma / Q000096:biosynthesis / Q000235:genetics; D010455:Peptides; D010641:Phenotype; D011094:Polyethyleneimine; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D018874:Spheroids, Cellular; D014280:Triglycerides / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D052242:Adiponectin; C499919:Adipoq protein, mouse; D018955:CD36 Antigens; D019013:CD40 Antigens; D004041:Dietary Fats; D005227:Fatty Acids; D047495:PPAR gamma; D010455:Peptides; D012333:RNA, Messenger; D014280:Triglycerides; D014409:Tumor Necrosis Factor-alpha; D011094:Polyethyleneimine; D019787:Linoleic Acid; D005990:Glycerol