title: The steroidogenic enzyme Cyp11a1 is essential for development of peanut-induced intestinal anaphylaxis.
abstract: BACKGROUND
  Cytochrome P450, family 11, subfamily A, polypeptide 1 (Cyp11a1), a cytochrome P450 enzyme, is the first and rate-limiting enzyme in the steroidogenic pathway, converting cholesterol to pregnenolone. Cyp11a1 expression is increased in activated T cells.
  
  
  OBJECTIVE
  We sought to determine the role of Cyp11a1 activation in the development of peanut allergy and TH cell functional differentiation.
  
  
  METHODS
  A Cyp11a1 inhibitor, aminoglutethimide (AMG), was administered to peanut-sensitized and challenged mice. Clinical symptoms, intestinal inflammation, and Cyp11a1 levels were assessed. The effects of Cyp11a1 inhibition on T(H)1, T(H)2, and T(H)17 differentiation were determined. Cyp11a1 gene silencing was performed with Cyp11a1-targeted short hairpin RNA.
  
  
  RESULTS
  Peanut sensitization and challenge resulted in diarrhea, inflammation, and increased levels of Cyp11a1, IL13, and IL17A mRNA in the small intestine. Inhibition of Cyp11a1 with AMG prevented allergic diarrhea and inflammation. Levels of pregnenolone in serum were reduced in parallel. AMG treatment decreased IL13 and IL17A mRNA expression in the small intestine without affecting Cyp11a1 mRNA or protein levels. In vitro the inhibitor decreased IL13 and IL17A mRNA and protein levels in differentiated T(H)2 and T(H)17 CD4 T cells, respectively, without affecting GATA3, retinoic acid-related orphan receptor γt (RORγt), or T(H)1 cells and IFNG and T-bet expression. Short hairpin RNA-mediated silencing of Cyp11a1 in polarized T(H)2 CD4 T cells significantly decreased pregnenolone and IL13 mRNA and protein levels.
  
  
  CONCLUSIONS
  Cyp11a1 plays an important role in the development of peanut allergy, regulating peanut-induced allergic responses through effects on steroidogenesis, an essential pathway in T(H)2 differentiation. Cyp11a1 thus serves as a novel target in the regulation and treatment of peanut allergy.
authors.affiliation: Division of Cell Biology, Department of Pediatrics, National Jewish Health, Denver, Colo.
authors.forename: Meiqin
authors.initials: M
authors.lastname: Wang
authors.forename: Julita
authors.initials: J
authors.lastname: Ramirez
authors.forename: Junyan
authors.initials: J
authors.lastname: Han
authors.forename: Yi
authors.initials: Y
authors.lastname: Jia
authors.forename: Joanne
authors.initials: J
authors.lastname: Domenico
authors.forename: Max A
authors.initials: MA
authors.lastname: Seibold
authors.forename: James R
authors.initials: JR
authors.lastname: Hagman
authors.forename: Erwin W
authors.initials: EW
authors.lastname: Gelfand
mesh_terms: D000707:Anaphylaxis / Q000201:enzymology* / Q000235:genetics; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage / Q000235:genetics; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016207:Cytokines / Q000096:biosynthesis; D004195:Disease Models, Animal; D004789:Enzyme Activation; D005260:Female; D005786:Gene Expression Regulation; D020868:Gene Silencing; D007422:Intestines / Q000201:enzymology* / Q000276:immunology*; D051379:Mice; D021183:Peanut Hypersensitivity / Q000201:enzymology* / Q000235:genetics; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000201:enzymology / Q000276:immunology; D058504:Th17 Cells / Q000166:cytology / Q000201:enzymology / Q000276:immunology; D018418:Th2 Cells / Q000166:cytology / Q000201:enzymology / Q000276:immunology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D016207:Cytokines; D012333:RNA, Messenger; D014157:Transcription Factors; D002786:Cholesterol Side-Chain Cleavage Enzyme
keywords: AMG; Aminoglutethimide; CD4 T cells; CFP; Cyan fluorescent protein; Cyp11a1; Cytochrome P450, family 11, subfamily A, polypeptide 1; GC; Glucocorticoid; PE; Peanut extract; RORγt; RT-PCR; Real-time PCR; Retinoic acid–related orphan receptor γt; Short hairpin RNA; T(H)17; T(H)2; peanut allergy; shRNA