title: DHEA modulates the effect of cortisol on RACK1 expression via interference with the splicing of the glucocorticoid receptor.
abstract: OBJECTIVE
  Dehydroepiandrosterone (DHEA) is thought to be an anti-glucocorticoid hormone known to be fully functional in young people but deficient in aged humans. Our previous data suggest that DHEA not only counteracts the effect of cortisol on RACK1 expression, a protein required both for the correct functioning of immune cells and for PKC-dependent pathway activation, but also modulates the inhibitory effect of cortisol on LPS-induced cytokine production. The purpose of this study was to investigate the effect of DHEA on the splicing mechanism of the human glucocorticoid receptor (GR).
  
  
  METHODS
  The THP1 monocytic cell line was used as a cellular model. Cytokine production was measured by specific elisa. Western blot and real-time RT-PCR were used, where appropriate, to determine the effect of DHEA on GRs, serine/arginine-rich proteins (SRp), and RACK1 protein and mRNA. Small-interfering RNA was used to down-regulate GRβ.
  
  
  RESULTS
  DHEA induced a dose-related up-regulation of GRβ and GRβ knockdown completely prevented DHEA-induced RACK1 expression and modulation of cytokine release. Moreover, we showed that DHEA influenced the expression of some components of the SRps found within the spliceosome, the main regulators of the alternative splicing of the GR gene.
  
  
  CONCLUSIONS
  These data contribute to our understanding of the mechanism of action of DHEA and its effect on the immune system and as an anti-glucocorticoid agent.
authors.affiliation: Department of Drug Sciences - Pharmacology, University of Pavia, Pavia, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Pinto
authors.affiliation: Department of Drug Sciences - Pharmacology, University of Pavia, Pavia, Italy.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Malacrida
authors.affiliation: Department of Drug Sciences - Pharmacology, University of Pavia, Pavia, Italy.
authors.forename: Jacopo
authors.initials: J
authors.lastname: Oieni
authors.affiliation: Department of Drug Sciences - Pharmacology, University of Pavia, Pavia, Italy.
authors.forename: Melania Maria
authors.initials: MM
authors.lastname: Serafini
authors.affiliation: 'Golgi Cenci' Foundation, Abbiategrasso, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Davin
authors.affiliation: Laboratory of Toxicology, DiSFeB, Università degli Studi di Milano, Milan, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Galbiati
authors.affiliation: Laboratory of Toxicology, DiSFeB, Università degli Studi di Milano, Milan, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Corsini
authors.affiliation: Department of Drug Sciences - Pharmacology, University of Pavia, Pavia, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Racchi
mesh_terms: D000305:Adrenal Cortex Hormones / Q000494:pharmacology; D017398:Alternative Splicing / Q000187:drug effects*; D002460:Cell Line; D003687:Dehydroepiandrosterone / Q000494:pharmacology*; D019204:GTP-Binding Proteins / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D055785:Gene Knockdown Techniques; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology*; D016209:Interleukin-8 / Q000187:drug effects / Q000378:metabolism; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism; D009363:Neoplasm Proteins / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects* / Q000378:metabolism; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000305:Adrenal Cortex Hormones; C508606:CXCL8 protein, human; D005938:Glucocorticoids; D016209:Interleukin-8; C497713:NR3C1 protein, human; D009363:Neoplasm Proteins; C419368:RACK1 protein, human; D012333:RNA, Messenger; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface; D011965:Receptors, Glucocorticoid; C121943:glucocorticoid receptor beta; D003687:Dehydroepiandrosterone; D019204:GTP-Binding Proteins; D006854:Hydrocortisone