title: 3,5-diiodo-L-thyronine modifies the lipid droplet composition in a model of hepatosteatosis.
abstract: OBJECTIVE
  Fatty acids are the main energy stores and the major membrane components of the cells. In the hepatocyte, fatty acids are esterified to triacylglycerols (TAGs) and stored in lipid droplets (LDs). The lipid lowering action of 3,5-diiodo-L-thyronine (T2) on an in vitro model of hepatosteatosis was investigated in terms of fatty acid and protein content of LDs, lipid oxidation and secretion.
  
  
  METHODS
  FaO cells were exposed to oleate/palmitate, then treated with T2.
  
  
  RESULTS
  T2 reduced number and size of LDs, and modified their acyl composition by decreasing the content of saturated (SFA) vs monounsaturated (MUFA) fatty acids thus reversing the SFA/MUFA ratio. The expression of the LD-associated proteins adipose differentiation-related protein (ADRP), oxidative tissue-enriched PAT protein (OXPAT), and adipose triglyceride lipase (ATGL) was increased in 'steatotic' cells and further up-regulated by T2. Moreover, T2 stimulated the mitochondrial oxidation by up-regulating carnitine-palmitoyl-transferase (CPT1), uncoupling protein 2 (UCP2) and very long-chain acyl-coenzyme A dehydrogenase (VLCAD).
  
  
  CONCLUSIONS
  T2 leads to mobilization of TAGs from LDs and stimulates mitochondrial oxidative metabolism of fatty acids, in particular of SFAs, and thus enriches of MUFAs the LDs. This action may protect the hepatocyte from excess of SFAs that are more toxic than MUFAs.
authors: Dipartimento di Scienze della Terra, dell'Ambiente e della Vita, Università degli Studi di Genova, Genova, Italy.
authors: Elena
authors: E
authors: Grasselli
authors: Adriana
authors: A
authors: Voci
authors: Laura
authors: L
authors: Canesi
authors: Annalisa
authors: A
authors: Salis
authors: Gianluca
authors: G
authors: Damonte
authors: Andrea D
authors: AD
authors: Compalati
authors: Fernando
authors: F
authors: Goglia
authors: Gabriella
authors: G
authors: Gallo
authors: Laura
authors: L
authors: Vergani
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004104:Diiodothyronines / Q000633:toxicity*; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism; D005234:Fatty Liver / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D047908:Intracellular Signaling Peptides and Proteins / Q000096:biosynthesis; D008049:Lipase / Q000096:biosynthesis; D050356:Lipid Metabolism / Q000187:drug effects*; D008930:Mitochondria, Liver / Q000378:metabolism* / Q000473:pathology; D008954:Models, Biological; D009124:Muscle Proteins / Q000096:biosynthesis; D019301:Oleic Acid / Q000378:metabolism / Q000494:pharmacology; D010084:Oxidation-Reduction; D019308:Palmitic Acid / Q000378:metabolism / Q000494:pharmacology; D000070797:Perilipin-5; D051381:Rats; D000217:Acyltransferases
chemical_list: D004104:Diiodothyronines; D004791:Enzyme Inhibitors; D005229:Fatty Acids, Monounsaturated; D047908:Intracellular Signaling Peptides and Proteins; D008049:Lipase; D009124:Muscle Proteins; D019301:Oleic Acid; D019308:Palmitic Acid; D000070797:Perilipin-5; C544353:PLIN5 protein, rat; C030103:3,5-diiodothyronine; C571275:PNPLA2 protein, rat; D000217:Acyltransferases