Glucocorticoid up-regulates mimecan expression in corticotroph cells.
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.
Ma
Qin-Yun
QY
Ruijin Hospital, Shanghai Institute of Endocrinology, State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University (SJTU) School of Medicine, Shanghai, China.
Zuo
Chun-Lin
CL
Ma
Jun-Hua
JH
Zhang
Xiao-Na
XN
Ru
Ying
Y
Li
Ping
P
Pan
Chun-Ming
CM
Liu
Zhi
Z
Cao
Huang-Ming
HM
Chen
Ming-Dao
MD
Song
Huai-Dong
HD
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*
D005938:Glucocorticoids; D006023:Glycoproteins; D006727:Hormone Antagonists; D036341:Intercellular Signaling Peptides and Proteins; C512905:Ogn protein, rat; D012333:RNA, Messenger; D015735:Mifepristone