The expression of the new epididymal luminal protein of PDZ domain containing 1 is decreased in asthenozoospermia / 亚洲男科学杂志(英文版)

Spermatozoa are not mature until they transit the epididymis where they acquire motility and the ability to fertilize an egg through sequential modifications. The epididymis has three functional regions, caput, corpus, and cauda, and the luminal proteins of the epididymis play important roles in the above modifications. However, the proteins with differential enrichment between the caput and cauda are still largely unknown. To reveal the functions of the caput and cauda during sperm maturation, luminal proteins from caput and cauda of mice were analyzed by isobaric tag for relative and absolute quantitation (iTRAQ). Overall, 128 differentially enriched proteins were found, of which 46 were caput enriched and 82 were cauda enriched. Bioinformatic analysis showed that lipid metabolism was active in the caput; while anion- and cation-binding activity and phosphorus and organophosphate metabolism were active in the cauda. A new epididymal luminal protein, the caput-enriched PDZ domain containing 1 (Pdzk1), also named Na+/H+ exchange regulatory cofactor 3 (NHERF3), which plays a critical role in cholesterol metabolism and carnitine transport, was found in the lipid metabolism. Western blotting and immunofluorescence analyses showed that Pdzk1 was expressed in the epididymis but not in the testis, and localized at the middle piece of the sperm tail. Pdzk1 protein level was also reduced in the spermatozoa in case of asthenozoospermic patients compared with that in normozoospermic men, suggesting that Pdzk1 may participate in sperm maturation regulation and may be associated with male infertility. These results may provide new insights into the mechanisms of sperm maturation and male infertility.

Androgen/androgen receptor directly regulates the expression of Caveolin-1 in mouse epididymides / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the mechanisms of androgen/androgen receptor (AR) regulating the expression of Caveolin-1 in the mouse epididymis.</p><p><b>METHODS</b>The AR binding sites associated with the Caveolin-1 gene were identified by searching the database of genomewide AR binding sites in mouse epididymides obtained from chromatin immunoprecipitation-sequencing (ChIP-seq). Total RNA was extracted from the epididymal tissues of normal and castrated mice and those castrated but supplemented with testosterone propionate, and the expression of Caveolin-1 mRNA was detected by RT-PCR and RT-qPCR. ChIP was performed with AR antibodies, and ChIP-PCR and ChIP-qPCR were used to determine the in vivo AR occupancies on the two sites associated with Caveolin-1.</p><p><b>RESULTS</b>Two AR binding sites associated with Caveolin-1 were found in the database, both located in the second intron region. After castration, the expression of Caveolin-1 was significantly increased, 1.8 +/- 0.17 times that of the control group (P < 0.05), and the fold enrichments of the two AR binding sites were dramatically reduced from 13.5 +/- 1.47 and 10.5 +/- 1.03 to 1.05 +/- 0.17 and 1.4 +/- 0.14, respectively (P < 0.01). After androgen supplement, however, the expression of Caveolin-1 was decreased to normal (P < 0.05), and the fold enrichments of the two AR binding sites significantly increased to 16.4 +/- 2.6 and 10 +/- 0.92, respectively (P < 0.01).</p><p><b>CONCLUSION</b>Caveolin-1 is a bona fide AR direct target gene in the mouse epididymis, and its expression is negatively regulated by androgen. These findings have provided a new insight into the androgen/AR regulatory network in mouse epididymides.</p>