WCRB2014 POSTER PRESENTATIONS (1) (335 abstracts)
1Justus-Liebig Universität, Giessen, Germany; 2UKE, Hamburg, Germany.
Introduction: Peroxisomes are ubiquitous organelles, which play an essential role in human physiology. Besides other metabolic pathways, peroxisomes are involved in β-oxidation of fatty acids, ROS-metabolism, and cholesterol synthesis, wherefore alterations of peroxisomal metabolism might affect steroid metabolism and the regulation of corresponding signaling pathways. Indeed male patients with peroxisomal dysfunction exhibit either cryptorchidism or a range of testicular pathologies leading to male infertility.
Materials and methods: We used the mouse tumor Leydig cell line (MLTC-1) and mouse primary Leydig cells to knockdown the Pex13 gene by transient transfection using microporation. The resulting phenotype was characterized by immunofluorescence, ROS− and glutathione assays, western blots, qRT-PCR, and RIAs/ELISAs.
Results and discussion: Using Pex13-RNAi technology we show that peroxisomal dysfunction in Leydig cells, as monitored by mistargeting of peroxisomal enzymes to the cytoplasm, leads to an increase in ROS production and mitochondrial dysfunction. The hCG-mediated induction of the intramitochondrial 30 kDa mature form of StAR protein was blocked in Leydig cells with peroxisome deficiency. Moreover, we found an up-regulation of aromatase and estrogen receptor alpha expression. Finally, we show that peroxisomal knockdown leads to significantly reduced levels of progesterone, testosterone, and estrone synthesis. In contrast, an increased level of estradiol was noted. Our results suggest that peroxisome dysfunction induces oxidative stress, mitochondrial alterations, and androgen/estrogen imbalance, which may contribute to the pathogenesis of male infertility.