Dehydroascorbic acid taken up by glucose transporters stimulates estradiol production through inhibition of JNK/c-Jun/AP1 signaling in JAR cells.
We have previously demonstrated that the reduced form of vitamin C (l-ascorbic acid, AA) is able to induce the production of both steroid and peptide hormones in human choriocarcinoma cells. Here, we attempted to investigate the role and underlying mechanism of the oxidized form of vitamin C, dehydroascorbic acid (DHA), in steroidogenesis in primary human cytotrophoblasts and human choriocarcinoma cells. Messenger RNA and protein levels of steroidogenic enzymes including P450 cholesterol side-chain cleavage enzyme (P450scc), 3β-hydroxysteroid dehydrogenase type 1 (3β-HSD1), 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1) and aromatase were examined by quantitative RT-PCR and western blots, respectively. Progesterone (P4) and estradiol (E2) levels were determined by enzyme immunoassays. Knockdown of c-Jun was achieved by lentivirus-mediated shRNA, and signaling pathways implicated in DHA-induced steroidogenesis were examined by western blots and dual-luciferase assays. DHA dose-dependently induced the expression of steroidogenic enzymes including 3β-HSD1, 17β-HSD1 and aromatase at both mRNA and protein levels, and subsequently increased the production of E2 but not P4. These effects were synergized by diethylmaleate, a glutathione-depleting compound, and α-tocopherol, a reducing agent, but robustly attenuated by inhibition of DHA transportation by phloretin or 2-deoxy-d-glucose. DHA time-dependently inhibited JNK and c-Jun phosphorylation, and dose-dependently reduced AP1 reporter activity. JNK signaling pathway-specific inhibitor SP600125 and c-Jun shRNA both significantly increased the expression of steroidogenic enzymes and E2 production regardless of the presence or absence of DHA. These findings suggest that DHA is able to induce steroidogenesis through inhibition of JNK/c-Jun/AP1 signaling, and may therefore play indispensable roles in pregnancy maintenance.
Department of Pharmacology, Zhejiang University, Medical School, Hangzhou 310058, China The Second Affiliated Hospital, Zhejiang University, Medical School, Hangzhou 310009, China.
Yongjie
Y
Wang
Department of Pharmacology, Zhejiang University, Medical School, Hangzhou 310058, China.
Chao
C
Tang
Department of Pharmacology, Zhejiang University, Medical School, Hangzhou 310058, China.
Minglan
M
Wu
Department of Pharmacology, Zhejiang University, Medical School, Hangzhou 310058, China.
Yibin
Y
Pan
Department of Pharmacology, Zhejiang University, Medical School, Hangzhou 310058, China.
Hongfeng
H
Ruan
Department of Pharmacology, Zhejiang University, Medical School, Hangzhou 310058, China.
Linling
L
Chen
Department of Pharmacology, Zhejiang University, Medical School, Hangzhou 310058, China The Second Affiliated Hospital, Zhejiang University, Medical School, Hangzhou 310009, China.
Hongyi
H
Yao
The First Affiliated Hospital, Zhejiang University, Medical School, Hangzhou 310009, China.
Haibin
H
Zhu
Department of Pharmacology, Zhejiang University, Medical School, Hangzhou 310058, China xiwu@zju.edu.cn.
Ximei
X
Wu
D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D001141:Aromatase / Q000378:metabolism; D045744:Cell Line, Tumor; D002822:Choriocarcinoma / Q000378:metabolism; D003683:Dehydroascorbic Acid / Q000378:metabolism*; D003847:Deoxyglucose / Q000494:pharmacology; D004958:Estradiol / Q000378:metabolism*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D010693:Phloretin / Q000494:pharmacology; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D014327:Trophoblasts / Q000187:drug effects / Q000378:metabolism
D016755:Proto-Oncogene Proteins c-jun; D004958:Estradiol; D003847:Deoxyglucose; D015067:17-Hydroxysteroid Dehydrogenases; D015096:3-Hydroxysteroid Dehydrogenases; C044256:3 (or 17)-beta-hydroxysteroid dehydrogenase; D001141:Aromatase; D010693:Phloretin; D003683:Dehydroascorbic Acid
Ap1; JNK; dehydroascorbic acid; estradiol; trophoblasts