title: FoxO is required for the activation of hypertrehalosemic hormone expression in cockroaches.
abstract: BACKGROUND
  FoxO proteins are a subgroup of the Forkhead-box family of transcription factors, which function as the main transcriptional effectors of the insulin receptor pathway. This pathway, activated by the binding of insulin or IGFs (or insect insulin-like peptides), promotes the phosphorylation and inactivation of FoxO because of its export from the nucleus to the cytoplasm. The homolog of FoxO in the cockroach Blattella germanica works in a situation of nutrient shortage by inhibiting the endocrine induction of reproduction.
  
  
  METHODS
  Using Blattella germanica as a model, we studied the functions of FoxO using RNA interference methodologies. We analyzed the mRNA levels of hypertrehalosemic hormone (HTH) and genes related to lipolysis, glycogenolysis and gluconeogenesis and quantified triacylglycerides, glycogen and trehalose.
  
  
  RESULTS
  FoxO knockdown eliminates the starvation-induced expression of HTH in the corpora cardiaca. In addition, FoxO knockdown prevents the activation of the expression of Brummer lipase, glycogen phosphorylase and phosphoenolpyruvate carboxylase in the fat body of starved females.
  
  
  CONCLUSIONS
  Starvation-induced activation of FoxO stimulates the transcription of different genes related to catabolic processes, including HTH and genes involved in lipolysis, glycogenolysis and gluconeogenesis.
  
  
  CONCLUSIONS
  Our results show conservation in the action of the transcription factor FoxO in the activation of catabolic processes from basal insects to vertebrates. The results also describe a new and essentially different mode of action of transcription factor FoxO, which works through the activation of neuropeptide HTH expression, which will subsequently produce its own catabolic stimulatory function.
authors.affiliation: Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
authors.forename: Songül
authors.initials: S
authors.lastname: Süren-Castillo
authors.forename: Marc
authors.initials: M
authors.lastname: Abrisqueta
authors.forename: José L
authors.initials: JL
authors.lastname: Maestro
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D003058:Cockroaches / Q000378:metabolism*; D005260:Female; D051858:Forkhead Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism*; D050261:Glycogenolysis; D006458:Hemolymph / Q000378:metabolism*; D009479:Neuropeptides / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D013217:Starvation; D014280:Triglycerides / Q000378:metabolism
chemical_list: D051858:Forkhead Transcription Factors; D009479:Neuropeptides; D034741:RNA, Small Interfering; D014280:Triglycerides; C084112:hypertrehalosemic hormone; D006003:Glycogen
keywords: Blattella germanica; Catabolism; FoxO; Glucagon; Hypertrehalosemic/adipokinetic hormone; Insulin