title: Release of a specific set of proinflammatory adipokines by differentiating 3T3-L1 cells.
abstract: OBJECTIVE
  Although there is a large amount of data on the role of preadipocytes in promoting the release of proinflammatory cytokines and chemokines in response to macrophage-derived cytokines, the direct role of insulin and saturated fatty acids in modulating the release of inflammatory cytokines by cells differentiating along the adipocytic lineage is less understood.
  
  
  METHODS
  3T3-L1 murine preadipocyte cells were cultured for 3 d in a proliferating medium in the presence or absence of insulin 0.2 nmol/L plus palmitic acid 1 μmol/L. In parallel, 3T3-L1 cells were cultured in a differentiation medium containing dexamethasone, insulin, and isobutyl methyl xanthine in the absence or presence of palmitic acid for 3 d. The levels of several cytokines were evaluated in the culture supernatants by a bead-based multiplex immunoassay.
  
  
  RESULTS
  Under the proliferation conditions, insulin plus palmitic acid promoted a significant increase in the release of interleukin-6, keratinocyte-derived chemokine (KC)/chemokine ligand-1 (CXCL-1), monocyte chemotactic protein-1 (MCP-1), and regulated and normal T cells expressed and presumably secreted (RANTES) by 3T3-L1 preadipocytes. Of note, the release of KC/CXCL-1, MCP-1, and RANTES increased significantly with adipocytic differentiation, and the addition of palmitic acid to differentiating 3T3-L1 cells resulted in a further significant promotion of KC/CXCL1, MCP-1, and RANTES, coupled to the increase of additional cytokines.
  
  
  CONCLUSIONS
  Taken together, these data show that a restricted common group of cytokines/chemokines (KC/CXCL1, MCP-1, and RANTES) is upregulated in proliferating and differentiating 3T3-L1 adipocytes in response to insulin and palmitic acid and that differentiating adipocytes respond with an increased range of cytokines with respect to proliferating 3T3-L1 preadipocytes.
authors.affiliation: Department of Morphology and Embryology and LTTA Centre, University of Ferrara, Ferrara, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Melloni
authors.forename: Giorgio
authors.initials: G
authors.lastname: Zauli
authors.forename: Claudio
authors.initials: C
authors.lastname: Celeghini
authors.forename: Ilaria
authors.initials: I
authors.lastname: Volpi
authors.forename: Paola
authors.initials: P
authors.lastname: Secchiero
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D054392:Adipokines / Q000378:metabolism*; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D049109:Cell Proliferation; D018932:Chemokine CCL2 / Q000378:metabolism; D018946:Chemokine CCL5 / Q000378:metabolism; D054360:Chemokine CXCL1 / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology; D015850:Interleukin-6 / Q000378:metabolism; D051379:Mice; D019308:Palmitic Acid / Q000494:pharmacology
chemical_list: D054392:Adipokines; C491768:Ccl2 protein, mouse; C503460:Ccl5 protein, mouse; D018932:Chemokine CCL2; D018946:Chemokine CCL5; D054360:Chemokine CXCL1; C475895:Cxcl1 protein, mouse; D018836:Inflammation Mediators; D007328:Insulin; D015850:Interleukin-6; D019308:Palmitic Acid