Double-edged sword: effects of human sperm reactive oxygen species on embryo development in IVF cycles.

BACKGROUND: The exact role of sperm reactive oxygen species (ROS) in early embryo development has yet to be fully identified, and most of existing research did not differentiate female infertility factors, ignoring the importance of oocyte quality in embryo development and the large differences in oocyte quality in women with infertility of different etiologies. And there has been no relevant report on whether different types of sperm ROS have distinct effects on embryo development. This study aimed to study the impact of selected sperm ROS, namely, sperm mitochondrial ROS (mROS) and hydrogen peroxide, on human embryo development after conventional in vitro fertilization (IVF) cycles in patients with normo-ovulatory infertility vs. anovulatory infertility. METHODS: This was a prospective investigation including 393 couples underwent IVF cycles, among whom 90 patients had anovulatory infertility and 303 patients had normo-ovulatory infertility in a public university-affiliated in vitro fertilization center. Sperm mROS and hydrogen peroxide testing were performed by flow cytometry and analyzed for their relationship with embryo development indices on days 1-6 after IVF. Multivariate logistic regression analysis was used to control for female potential confounders. The nonlinear effects of sperm ROS on embryo development were analyzed by the Restricted cubic spline (RCS) method. RESULTS: 1. Multivariate linear logistic regression analysis showed that high proportion of mROS positive sperm improved the 2PN rate (OR = 1.325, 95% CI: 1.103-1.595), day 3 embryo utilization rate (OR = 1.362, 95% CI: 1.151-1.614) and good-quality day 3 embryo rate (OR = 1.391, 95% CI: 1.089-1.783) in patients with anovulatory infertility. High percentage of sperm mROS and hydrogen peroxide had adverse effects on cleavage-stage embryo and blastocyst development in patients with normo-ovulatory infertility. 2. For patients with polycystic ovarian syndrome (PCOS) anovulatory infertility, there were significant distinct effects on embryo development indices between sperm mROS and hydrogen peroxide, and the increased rate of sperm mROS improved the good-quality day 3 embryo rate (OR = 1.435, 95% CI: 1.045-1.981); however, high percentage of sperm hydrogen peroxide reduced the blastocyst utilization rate (OR = 0.555, 95% CI: 0.353-0.864) and the good-quality blastocyst rate (OR = 0.461, 95% CI: 0.292-0.718). 3. Multivariate RCS analysis revealed that sperm ROS had a nonlinear (such as a parabolic curve) effect on embryo development in patients with anovulatory infertility (P < 0.05), and either greatly increased or greatly decreased affected cleavage-stage embryo and blastocyst development. The effects of sperm ROS in patients with normo-ovulatory infertility were both linear and nonlinear. CONCLUSIONS: These findings indicate that contrary effects of sperm mROS on embryo development depending on whether patients treated with IVF cycles had normal ovulation. Regardless of whether the patients ovulated normally, increased sperm hydrogen peroxide rate damaged blastocyst development. It is necessary to evaluate male sperm ROS levels and the female ovulatory state to determine an individualized intervention plan before starting cycles, as this may be beneficial for infertile couples.

Scanning of novel cancer/testis proteins by human testis proteomic analysis.

The testes are where spermatogenesis, the sperm-generating process that is unique to men, occurs. Importantly, human spermatogenesis and tumorigenesis share key similarities. Until now, only a few proteins in the human testis have been identified due to limitations of available technology. In this paper, using an advanced proteomics platform, we have identified 7346 unique proteins within the human testis with a high degree of confidence. Immunohistochemistry data from the Human Protein Atlas database show over 90% (1833/2020) of identified proteins can be detected in the human testis using specific antibodies. To make the data widely available to the scientific community, an online Human Testis Proteome Database (HTPD, http://reprod.njmu.edu.cn/htpd/) was built. Many of the identified human testicular proteins are associated with human infertility, especially human testicular predominantly expressed proteins. We characterized six novel cancer/testis genes (TMPRSS12, TPPP2, PRSS55, DMRT1, PIWIL1, HEMGN), which map to cancer-associated genetic variants positions, in both the cancer and testis tissues using genome-wide analyses. Our results provide a molecular connection between spermatogenesis and tumorigenesis and broaden the range of cancer antigen choice available for immunotherapy.

In-depth proteomic analysis of the human sperm reveals complex protein compositions.

The male gamete (sperm) can fertilize an egg, and pass the male genetic information to the offspring. It has long been thought that sperm had a simple protein composition. Efforts have been made to identify the sperm proteome in different species, and only about 1000 proteins were reported. However, with advanced mass spectrometry and an optimized proteomics platform, we successfully identified 4675 human sperm proteins, of which 227 were testis-specific. This large number of identified proteins indicates the complex composition and function of human sperm. Comparison with the sperm transcriptome reveals little overlap, which shows the importance of future studies of sperm at the protein level. Interestingly, many signaling pathways, such as the IL-6, insulin and TGF-beta receptor signaling pathways, were found to be overrepresented. In addition, we found that 500 proteins were annotated as targets of known drugs. Three of four drugs studied were found to affect sperm movement. This in-depth human sperm proteome will be a rich resource for further studies of sperm function, and will provide candidate targets for the development of male contraceptive drugs.

The expression and localization of a novel protein phosphatase inhibitor 2810408A11Rik in mouse testis and sperm.

This study investigated the expression and distribution of 2810408A11Rik in mouse testis and sperm, and explored its role in spermatogenesis and sperm function. The expression levels of 2810408A11Rik mRNA in multiple tissue samples were analyzed using bioinformatic resources and RT-PCR technique. A specific rabbit polyclonal antibody was prepared by prokaryotic expression of 2810408A11Rik recombinant protein and utilized for animal immunization. Western blotting, immunohistochemistry and immunofluorescence were used to detect the expression and distribution of 2810408A11Rik. The results of the bioinformatic analysis and RT-PCR showed that 2810408A11Rik mRNA was specifically expressed in mouse testis, and 2810408A11Rik protein included a protein phosphatase inhibitor domain. Western blotting assays, immunohistochemistry and immunofluorescence confirmed the expression of 2810408A11Rik protein in mouse testis, especially in post-meiosis round and long spermatids, and that it is localized in the acrosome and the post-nucleus area of sperm. Our findings suggest that 2810408A11Rik may play an important role in spermatogenesis, sperm capacitation and fertilization.