ABSTRACT
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.
Subject(s)
Adult , Animals , Humans , Male , Mice , Asthenozoospermia/metabolism , Carrier Proteins/metabolism , Case-Control Studies , Epididymis/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Membrane Proteins , Sperm Maturation , Sperm Tail/metabolism , Spermatozoa/metabolism , Testis/metabolismABSTRACT
Objective·To investigate the effects and mechanisms of exogenous hydrogen sulfide on the proliferation, apoptosis, invasion and cisplatin resistance of human ovarian cancer cells. Methods·The human ovarian cancer cell line SKOV3 cells and human cisplatin resistant cell line SKOV3/DDP cells were studied. The effects of NaHS on cell proliferation, apoptosis and invasion in SKOV3 cells were detected respectively by CCK-8, flow cytometry and Transwell invasion assay. The effect of NaHS on cisplatin resistance in SKOV3 and SKOV3/DDP cells was detected by calculating the IC50 and IR. The phosphorylation levels of EGFR, PI3K and Akt in SKOV3 and SKOV3/DDP cells were assayed by Western blotting. After treated with erlotinib (EGFR inhibitor), LY294002 (PI3K inhibitor) and MK-2206 (Akt inhibitor), the phosphorylation levels of EGFR, PI3K and Akt in SKOV3 and SKOV3/DDP cells, as well as cell proliferation, invasion in SKOV3 cells and cisplatin resistance in SKOV3/DDP cells were detected. Results·Compared with the control group, NaHS could significantly promote the proliferation (P=0.000) and invasion (P=0.033) in SKOV3 cells; increase IC50 (P=0.027, P=0.009) and decrease IR of cisplatin (P=0.001, P=0.009) in SKOV3 and SKOV3/DDP cells. NaHS could activate EGFR (P=0.000, P=0.037), PI3K (P=0.009, P=0.013)and Akt(P=0.000,P=0.023)in SKOV3 and SKOV3/DDP cells.Erlotinib,LY294002 and MK-2206 could block the effects of NaHS on the proliferation (all P=0.000) and invasion (all P<0.01) in SKOV3 cells, and also reverse the effect of NaHS on the cisplatin resistance in SKOV3/DDP cells (all P=0.000). Conclusion·Exogenous hydrogen sulfide can induce the proliferation and invasion in SKOV3 cells, and promote the cisplatin resistance in SKOV3 and SKOV3/DDP cells, which mechanisms are related to activation of EGFR/PI3K/Akt signaling pathway.
