title: Glucocorticoid up-regulates mimecan expression in corticotroph cells.
abstract: Mimecan is a protein of unknown function that is expressed in the pituitary. The aim of this study is to clarify the regulation and intracellular localisation of mimecan gene expression in the pituitary. With immunohistochemistry, we observed that mimecan protein was co-expressed with ACTH in pituitary corticotroph cells. Northern and Western blot analyses revealed that mimecan expression and secretion in corticotroph cells were up-regulated by treating AtT-20 cells with glucocorticoid. Meanwhile, mimecan expression in rat primary culture pituitary cells was also promoted by glucocorticoid. Co-incubation of AtT-20 cells with RU486 and glucocorticoid completely reversed the induction of mimecan gene expression by glucocorticoid. In addition, luciferase reporter assays showed that the -1474/+43 promoter region of mimecan was sufficient for glucocorticoid-responsive mimecan expression. These data collectively suggest that mimecan expressed in pituitary corticotroph cells is increased by glucocorticoid and that the up-regulation may be mediated by the classical GR pathways.
authors.affiliation: Ruijin Hospital, Shanghai Institute of Endocrinology, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University (SJTU) School of Medicine, Shanghai, China.
authors.forename: Qin-Yun
authors.initials: QY
authors.lastname: Ma
authors.forename: Chun-Lin
authors.initials: CL
authors.lastname: Zuo
authors.forename: Jun-Hua
authors.initials: JH
authors.lastname: Ma
authors.forename: Xiao-Na
authors.initials: XN
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Ru
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Chun-Ming
authors.initials: CM
authors.lastname: Pan
authors.forename: Zhi
authors.initials: Z
authors.lastname: Liu
authors.forename: Huang-Ming
authors.initials: HM
authors.lastname: Cao
authors.forename: Ming-Dao
authors.initials: MD
authors.lastname: Chen
authors.forename: Huai-Dong
authors.initials: HD
authors.lastname: Song
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D052680:Corticotrophs / Q000187:drug effects*; D005938:Glucocorticoids / Q000494:pharmacology*; D006023:Glycoproteins / Q000378:metabolism*; D006727:Hormone Antagonists / Q000494:pharmacology; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D015735:Mifepristone / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D005938:Glucocorticoids; D006023:Glycoproteins; D006727:Hormone Antagonists; D036341:Intercellular Signaling Peptides and Proteins; C512905:Ogn protein, rat; D012333:RNA, Messenger; D015735:Mifepristone