title: Parkin-mediated mitophagy is downregulated in browning of white adipose tissue.
abstract: Browning of white adipose tissue (WAT) promotes increased energy expenditure through the action of uncoupling protein 1 (UCP1) and is an attractive target to promote weight loss in obesity. Lowering of mitochondrial membrane potential by UCP1 is uniquely beneficial in this context; in other tissues, reduced membrane potential promotes mitochondrial clearance via mitophagy. It is unknown how parkin-mediated mitophagy is regulated in beige adipocytes.
  
  
  
  The relationship between parkin expression and WAT browning was investigated in 3T3-L1 adipocytes and parkin-deficient male C57BL/6 mice in response to pharmacological browning stimuli.
  
  
  
  Rosiglitazone treatment in 3T3-L1 adipocytes promoted mitochondrial biogenesis, UCP1 expression, and mitochondrial uncoupling. Parkin expression was decreased and reduced mitochondrial-associated parkin, and p62 indicated a reduction in mitophagy activity. Parkin overexpression prevented mitochondrial remodeling in response to rosiglitazone. In CL 316,243-treated wild-type mice, decreased parkin expression was observed in subcutaneous inguinal WAT, where UCP1 was strongly induced. CL 316,243 treatment weakly induced UCP1 expression in the gonadal depot, where parkin expression was unchanged. In contrast, parkin-deficient mice exhibited robust UCP1 expression in gonadal WAT following CL 316,243 treatment.
  
  
  
  WAT browning was associated with a decrease in parkin-mediated mitophagy, and parkin expression antagonized browning of WAT.
authors.affiliation: The Cedars-Sinai Heart Institute, Barbra Streisand Women's Heart Center, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: David
authors.initials: D
authors.lastname: Taylor
authors.affiliation: The Cedars-Sinai Heart Institute, Barbra Streisand Women's Heart Center, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Roberta A
authors.initials: RA
authors.lastname: Gottlieb
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000502:physiology; D002001:Adipose Tissue, Brown / Q000187:drug effects*; D052436:Adipose Tissue, White / Q000503:physiopathology*; D000818:Animals; D004149:Dioxoles / Q000494:pharmacology; D015536:Down-Regulation; D004734:Energy Metabolism; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007473:Ion Channels / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000187:drug effects; D063306:Mitophagy / Q000502:physiology*; D009765:Obesity / Q000378:metabolism; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000494:pharmacology; D044767:Ubiquitin-Protein Ligases / Q000502:physiology*; D000071256:Uncoupling Protein 1 / Q000187:drug effects
chemical_list: D004149:Dioxoles; D007004:Hypoglycemic Agents; D007473:Ion Channels; D045162:Thiazolidinediones; C000604372:Ucp1 protein, mouse; D000071256:Uncoupling Protein 1; D000077154:Rosiglitazone; C076126:disodium (R,R)-5-(2-((2-(3-chlorophenyl)-2-hydroxyethyl)-amino)propyl)-1,3-benzodioxole-2,3-dicarboxylate; D044767:Ubiquitin-Protein Ligases; C111567:parkin protein