title: Cytotoxic mechanism related to dihydrolipoamide dehydrogenase in Leydig cells exposed to heavy metals.
abstract: Heavy metals are common environmental toxicants with adverse effects on steroid biosynthesis. The importance of mitochondria has been recognized in cytotoxic mechanism of heavy metals on Leydig cells these years. But it is still poorly known. Our previous study reported that dihydrolipoamide dehydrogenase (DLD) located on the mitochondria was significantly decreased in Leydig cells exposed to cadmium, which suggested that DLD might be involved in the cytotoxic effects. Therefore, the altered expression of DLD was validated in rats and R2C cells exposed to cadmium, manganese and lead, and the role of DLD in the steroid synthesis pathway cAMP/PKA-ERK1/2 was investigated in this study. With a low expression of DLD, heavy metals dramatically reduced the levels of steroid hormone by inhibiting the activation of cAMP/PKA, PKC signaling pathway and the steroidogenic enzymes StAR, CYP11A1 and 3β-HSD. After knockdown of DLD in R2C cells, progesterone synthesis was reduced by 40%, and the intracellular concentration of cAMP, protein expression of StAR, 3β-HSD, PKA, and the phosphorylation of ERK1/2 were also decreased. These results highlight that DLD is down-regulation and related to steroid biosynthesis in Leyig cells exposed to heavy metals; cAMP/PKA act as downstream effector molecules of DLD, which activate phosphorylation of ERK1/2 to initiate the steroidogenesis.
authors.affiliation: Institute of Biomedicine, and National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou 510632, China.
authors.forename: Xunmin
authors.initials: X
authors.lastname: Ji
authors.affiliation: Institute of Biomedicine, and National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou 510632, China.
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Li
authors.affiliation: Institute of Biomedicine, and National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou 510632, China.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Cell Biology & Institute of Biomedicine, College of Life Science and Technology, Jinan University, National Engineering Research Center of Genetic Medicine, Guangdong Provincial Key Laboratory of Bioengineering Medicine, 510632, China.
authors.forename: Junqi
authors.initials: J
authors.lastname: Li
authors.affiliation: Institute of Biomedicine, and National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou 510632, China.
authors.forename: Huajian
authors.initials: H
authors.lastname: Tian
authors.affiliation: Institute of Biomedicine, and National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou 510632, China.
authors.forename: Zengli
authors.initials: Z
authors.lastname: Li
authors.affiliation: Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China.
authors.forename: Xuejuan
authors.initials: X
authors.lastname: Gao
authors.affiliation: Institute of Biomedicine, and National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Bioengineering Medicine, Jinan University, Guangzhou 510632, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Xiang
authors.affiliation: Institute of Biomedicine, and National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Bioengineering Medicine, Jinan University, Guangzhou 510632, China.
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Su
authors.affiliation: Institute of Biomedicine, and National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Bioengineering Medicine, Jinan University, Guangzhou 510632, China. Electronic address: tydhuang@jnu.edu.cn.
authors.forename: Yadong
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Institute of Biomedicine, and National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Bioengineering Medicine, Jinan University, Guangzhou 510632, China. Electronic address: tqhzhang@jnu.edu.cn.
authors.forename: Qihao
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D000818:Animals; D019256:Cadmium Chloride / Q000633:toxicity*; D002460:Cell Line; D002712:Chlorides / Q000633:toxicity*; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D008058:Dihydrolipoamide Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004789:Enzyme Activation; D007985:Leydig Cells / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008297:Male; D017895:Manganese Compounds; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009942:Organometallic Compounds / Q000633:toxicity*; D010766:Phosphorylation; D011374:Progesterone / Q000096:biosynthesis; D034622:RNA Interference; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection
chemical_list: D002712:Chlorides; D017895:Manganese Compounds; D009942:Organometallic Compounds; D011374:Progesterone; D000242:Cyclic AMP; D008058:Dihydrolipoamide Dehydrogenase; D017868:Cyclic AMP-Dependent Protein Kinases; C535149:Mapk1 protein, rat; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D019256:Cadmium Chloride; C025340:manganese chloride; C008261:lead acetate
keywords: Dihydrolipoamide dehydrogenase; Heavy metals; Leydig cells; Steroidogenesis