title: In vivo phosphoenolpyruvate carboxykinase promoter mapping identifies disrupted hormonal synergism as a target of inflammation during sepsis in mice.
abstract: In mammals, proper maintenance of blood glucose levels within narrow limits is one of the most critical prerequisites for healthy energy homeostasis and body function. Consequently, hyper- and hypoglycemia represent hallmarks of severe metabolic pathologies, including type II diabetes and acute sepsis, respectively. Although the liver plays a crucial role in the control of systemic glucose homeostasis, the molecular mechanisms of aberrant hepatic glucose regulation under metabolic stress conditions remain largely unknown. Here we report the development of a liver-specific adenoviral in vivo system for monitoring promoter activity of the key gluconeogenic enzyme gene phosphoenolpyruvate carboxykinase (PEPCK) in mice. By employing in vivo promoter deletion technology, the glucocorticoid response unit (GRU) and the cyclic adenosine monophosphate (cAMP)-responsive element (CRE) were identified as critical cis-regulatory targets of proinflammatory signaling under septic conditions. In particular, both elements were found to be required for inhibition of PEPCK transcription during sepsis, thereby mediating endotoxic hypoglycemia. Indeed, expression of nuclear receptor cofactor peroxisome proliferator-activator receptor coactivator 1alpha (PGC-1alpha), the molecular mediator of GRU/CRE synergism on the PEPCK promoter, was found to be specifically repressed in septic liver, and restoration of PGC-1alpha in cytokine-exposed hepatocytes blunted the inhibitory effect of proinflammatory signaling on PEPCK gene expression.
  
  
  CONCLUSIONS
  The dysregulation of hormonal synergism through the repression of PGC-1alpha as identified by in vivo promoter monitoring may provide a molecular rationale for hypoglycemia during sepsis, thereby highlighting the importance of hepatic glucose homeostasis for metabolic dysfunction in these patients.
authors.affiliation: Emmy Noether and Marie Curie Research Group Molecular Metabolic Control, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ) Heidelberg, Heidelberg, Germany.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Chichelnitskiy
authors.forename: Alexandros
authors.initials: A
authors.lastname: Vegiopoulos
authors.forename: Mauricio
authors.initials: M
authors.lastname: Berriel Diaz
authors.forename: Anja
authors.initials: A
authors.lastname: Ziegler
authors.forename: Anna
authors.initials: A
authors.lastname: Kleiman
authors.forename: Alexander
authors.initials: A
authors.lastname: Rauch
authors.forename: Jan
authors.initials: J
authors.lastname: Tuckermann
authors.forename: Stephan
authors.initials: S
authors.lastname: Herzig
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000502:physiology; D005938:Glucocorticoids / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D007249:Inflammation / Q000209:etiology*; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D020218:Response Elements; D018805:Sepsis / Q000378:metabolism*; D015398:Signal Transduction; D015534:Trans-Activators / Q000502:physiology; D014157:Transcription Factors
chemical_list: D005938:Glucocorticoids; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; D000242:Cyclic AMP; D010729:Phosphoenolpyruvate Carboxykinase (GTP); D005947:Glucose