Low-dose monobutyl phthalate stimulates steroidogenesis through steroidogenic acute regulatory protein regulated by SF-1, GATA-4 and C/EBP-beta in mouse Leydig tumor cells

Reproductive Biology and Endocrinology

Yubang Wang³  Zhong Li⁴  Hong Sun¹  Yankai Xia⁵  Aihua Gu⁵  Xiaocheng Li⁴  Jingjing Qin⁵  Yansu Chen²  Lianglin Qiu⁵  Xiumei Han⁵  Jing Lu⁵  Minjian Chen⁵  Congcong Dong⁵  Yanhui Hu⁵ 

[1] Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, 211166, China;Department of Molecular Cell Biology and Toxicology, Jiangsu Key Lab of Cancer Biomarkers, Prevention & Treatment, Cancer Center, School of Public Health, Nanjing Medical University, Nanjing, 211166, China;Safety Assessment and Research Center for Drug, Pesticide and Veterinary Drug of Jiangsu Province, Nanjing Medical University, Nanjing, 211166, China;Department of Nutrition and Food Hygiene, School of Public Health, Nanjing Medical University, Nanjing, 211166, China;Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China

关键词: Mouse Leydig tumor cells;    CCAAT/enhancer binding protein-beta;    GATA-4;    Steroidogenic factors 1;    Steroidogenic acute regulatory protein;    Progesterone;    Monobutyl phthalate;   

Others  :  810974
DOI  :  10.1186/1477-7827-11-72

 received in 2013-03-22, accepted in 2013-07-16,  发布年份 2013

【 摘 要 】

Background

The ubiquitous use of dibutyl phthalate (DBP), one of the most widely used plasticizers, results in extensive exposure to humans and the environment. DBP and its major metabolite, monobutyl phthalate (MBP), may alter steroid biosynthesis and their exposure may lead to damage to male reproductive function. Low-doses of DBP/MBP may result in increased steroidogenesis in vitro and in vivo. However, the mechanisms of possible effects of low-dose MBP on steroidogenesis remain unclear. The aim of present study was to elaborate the role of transcription factors and steroidogenic acute regulatory protein in low-dose MBP-induced distruption of steroidogenesis in mouse Leydig tumor cells (MLTC-1 cells).

Methods

In the present study, MLTC-1 cells were cultured in RPMI 1640 medium supplemented with 2 g/L sodium bicarbonate. Progesterone level was examined by I125-pregesterone Coat-A-Count radioimmunoassay (RIA) kits. mRNA and protein levels were assessed by reverse transcription-polymerase chain reaction (RT-PCR) and western blot, respectively. DNA-binding of several transcription factors was examined by electrophoretic mobility shift assay (EMSA).

Results

In this study, various doses of MBP (0, 10(−9), 10(−8), 10(−7), or 10(−6) M) were added to the medium followed by stimulation of MLTC-1 cells with human chorionic gonadotrophin (hCG). The results showed that MBP increased progesterone production and steroidogenic acute regulatory protein (StAR) mRNA and protein levels. However, the protein levels of cytochrome P450scc and 3 beta-hydroxy-steroid dehydrogenase (3 beta-HSD) were unchanged after MBP treatment. EMSA assay showed that DNA-binding of steroidogenic factors 1(SF-1), GATA-4 and CCAAT/enhancer binding protein-beta (C/EBP-beta) was increased in a dose-dependent manner after MBP exposure. Western blot tests were next employed and confirmed that the protein levels of SF-1, GATA-4 and C/EBP-beta were also increased. Additionally, western blot tests confirmed the expression of DAX-1, negative factor of SF-1, was dose-dependently down regulated after MBP exposure, which further confirmed the role of SF-1 in MBP-stimulated steroid biosynthesis.

Conclusions

In conclusion, we firstly delineated the regulation of StAR by transcription factors including SF-1, GATA-4 and C/EBP-beta maybe critical mechanism involved in low-dose MBP-stimulated steroidogenesis.

【 授权许可】

   
2013 Hu et al.; licensee BioMed Central Ltd.

【 图 表 】

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