Alterations in mitogen-activated protein kinase kinase and extracellular regulated kinase signaling in theca cells contribute to excessive androgen production in polycystic ovary syndrome.
We have investigated the involvement of the MAPK signaling pathway in increased androgen biosynthesis and CYP17 gene expression in women with polycystic ovary syndrome (PCOS). A comparison of MAPK kinase (MEK1/2) and ERK1/2 phosphorylation in propagated normal and PCOS theca cells, revealed that MEK1/2 phosphorylation was decreased more than 70%, and ERK1/2 phosphorylation was reduced 50% in PCOS cells as compared with normal cells. Infection with dominant-negative MEK1 increased CYP17 mRNA and dehydroepiandrosterone (DHEA) abundance, whereas constitutively active MEK1 reduced DHEA production and CYP17 mRNA abundance. Similarly, the MEK inhibitor, PD98059, increased CYP17 mRNA accumulation and CYP17 promoter activity to levels observed in PCOS cells. Remarkably, in theca cells maintained in the complete absence of insulin, ERK1/2 phosphorylation was decreased in PCOS theca cells as compared with normal theca cells, and CYP17 mRNA and DHEA synthesis were increased in PCOS theca cells. These studies demonstrate that in PCOS cells reduced levels of activated MEK1/2 and ERK1/2 are correlated with increased androgen production, irrespective of the insulin concentration. These findings implicate alterations in the MAPK pathway in the pathogenesis of excessive ovarian androgen production in PCOS.
Nelson-Degrave
Velen L
VL
Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine 500 University Drive H166, Hershey, Pennsylvania 17033, USA.
Wickenheisser
Jessica K
JK
Hendricks
Karen L
KL
Asano
Tomoichiro
T
Fujishiro
Midori
M
Legro
Richard S
RS
Kimball
Scot R
SR
Strauss
Jerome F
JF
McAllister
Jan M
JM
D000256:Adenoviridae / Q000378:metabolism; D000728:Androgens / Q000096:biosynthesis*; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002478:Cells, Cultured; D003687:Dehydroepiandrosterone / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D005799:Genes, Dominant; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007763:Lac Operon; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D009154:Mutation; D010053:Ovary / Q000378:metabolism; D010766:Phosphorylation; D011085:Polycystic Ovary Syndrome / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D013254:Steroid 17-alpha-Hydroxylase / Q000096:biosynthesis / Q000378:metabolism; D013256:Steroids / Q000378:metabolism; D013799:Theca Cells / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection
D000728:Androgens; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007328:Insulin; D012333:RNA, Messenger; D013256:Steroids; D003687:Dehydroepiandrosterone; D013254:Steroid 17-alpha-Hydroxylase; D048049:Extracellular Signal-Regulated MAP Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one