title: The phospholipase C inhibitor U73122 attenuates trans-10, cis-12 conjugated linoleic acid-mediated inflammatory signaling and insulin resistance in human adipocytes.
abstract: We have demonstrated that trans-10, cis-12 conjugated linoleic acid (18:2t10,c12)-mediated delipidation of human adipocytes was dependent on increased intracellular calcium and activation of inflammatory signaling in human primary adipocytes. These data are consistent with the actions of diacylglycerol and inositol triphosphate derived from phospholipase C (PLC)-dependent cell signaling. To test the hypothesis that PLC was an upstream activator of these cellular responses to 18:2t10,c12, primary cultures of human adipocytes were pretreated with 1-[6-((17β-3-methoxyestra-1,3,5 (10)-trien-17-yl)amino)hexyl]-1H-pyrrole-2,5-dione (U73122), a universal PLC inhibitor, followed by 18:2t10,c12 treatment. U73122 attenuated 18:2t10,c12-mediated insulin resistance within 48 h and suppression of the mRNA levels of peroxisome proliferator-activated receptor (PPAR)γ, insulin-stimulated glucose transporter-4, acetyl-CoA carboxylase-1, and stearoyl-CoA desaturase-1, and the protein levels of PPARγ within 18-24 h. U73122 inhibited 18:2t10,c12-mediated induction of the inflammatory-related genes calcium/calmodulin-dependent protein kinase-β, cyclooxygenase-2, monocyte chemoattractant protein-1, interleukin (IL)-6, and IL-8, secretion of IL-6 and IL-8, and the activation of extracellular signal-related kinase, c-Jun N-terminal kinase, and c-Jun within 18-24 h. Moreover, 18:2t10,c12 increased the mRNA levels of heat shock proteins within 6-24 h and intracellular calcium concentrations within 3 min, which were inhibited by U73122. Lastly, 18:2t10,c12 increased the abundance of PLCγ1 in the plasma membrane within 3 min. Taken together, these data suggest that PLC plays an important role in 18:2t10,c12-mediated activation of intracellular calcium accumulation, inflammatory signaling, delipidation, and insulin resistance in human primary adipocytes.
authors.affiliation: Department of Nutrition, University of North Carolina, Greensboro, NC, USA.
authors.forename: Wan
authors.initials: W
authors.lastname: Shen
authors.forename: Kristina
authors.initials: K
authors.lastname: Martinez
authors.forename: Chia Chi
authors.initials: CC
authors.lastname: Chuang
authors.forename: Michael
authors.initials: M
authors.lastname: McIntosh
mesh_terms: D000103:Acetyl-CoA Carboxylase / Q000235:genetics / Q000378:metabolism; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004041:Dietary Fats / Q000378:metabolism* / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology*; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000235:genetics / Q000378:metabolism*; D007333:Insulin Resistance; D008041:Linoleic Acids / Q000378:metabolism* / Q000494:pharmacology; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D051966:Phospholipase C gamma / Q000378:metabolism; D011760:Pyrrolidinones / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D013230:Stearoyl-CoA Desaturase / Q000235:genetics / Q000378:metabolism; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D004041:Dietary Fats; D004963:Estrenes; D051275:Glucose Transporter Type 4; D006360:Heat-Shock Proteins; D008041:Linoleic Acids; D047495:PPAR gamma; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; D012333:RNA, Messenger; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D013230:Stearoyl-CoA Desaturase; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D000103:Acetyl-CoA Carboxylase; D002118:Calcium