AF-2364 is a prospective spermicide candidate

Mitochondria-Targeted Compounds to Assess and Improve Human Sperm Function

Significance: Currently 10%-15% of couples in reproductive age face infertility issues. More importantly, male factor contributes to 50% of these cases (either alone or in combination with female causes). Among various reasons, impaired sperm function is the main cause for male infertility. Furthermore, mitochondrial dysfunction and oxidative stress due to increased reactive oxygen species (ROS) production, particularly of mitochondrial origin, are believed to be the main contributors. Recent Advances: Mitochondrial dysfunction, particularly due to increased ROS production, has often been linked to impaired sperm function/quality. For decades, different methods and approaches have been developed to assess mitochondrial features that might correlate with sperm functionality. This connection is now completely accepted, with mitochondrial functionality assessment used more commonly as a readout of sperm functionality. More recently, mitochondria-targeted compounds are on the frontline for both assessment and therapeutic approaches. Critical Issues: In this review, we summarize the current methods for assessing key mitochondrial parameters known to reflect sperm quality as well as therapeutic strategies using mitochondria-targeted antioxidants aiming to improve sperm function in various situations, particularly after sperm cryopreservation. Future Directions: Although more systematic research is needed, mitochondria-targeted compounds definitely represent a promising tool to assess as well as to protect and improve sperm function. Antioxid. Redox Signal. 37, 451-480.

Physiological Characterization of the Transporter-Mediated Uptake of the Reversible Male Contraceptive H2-Gamendazole Across the Blood-Testis Barrier

The blood-testis barrier (BTB) is formed by a tight network of Sertoli cells (SCs) to limit the movement of reproductive toxicants from the blood into the male genital tract. Transporters expressed at the basal membranes of SCs also influence the disposition of drugs across the BTB. The reversible, nonhormonal contraceptive, H2-gamendazole (H2-GMZ), is an indazole carboxylic acid analog that accumulates over 10 times more in the testes compared with other organs. However, the mechanism(s) by which H2-GMZ circumvents the BTB are unknown. This study describes the physiologic characteristics of the carrier-mediated process(es) that permit H2-GMZ and other analogs to penetrate SCs. Uptake studies were performed using an immortalized human SC line (hT-SerC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Uptake of H2-GMZ and four analogs followed Michaelis-Menten transport kinetics (one analog exhibited poor penetration). H2-GMZ uptake was strongly inhibited by indomethacin, diclofenac, MK-571, and several analogs. Moreover, H2-GMZ uptake was stimulated by an acidic extracellular pH, reduced at basic pHs, and independent of extracellular Na+, K+, or Cl- levels, which are intrinsic characteristics of OATP-mediated transport. Therefore, the characteristics of H2-GMZ transport suggest that one or more OATPs may be involved. However, endogenous transporter expression in wild-type Chinese hamster ovary (CHO), Madin-Darby canine kidney (MDCK), and human embryonic kidney-293 (HEK-293) cells limited the utility of heterologous transporter expression to identify a specific OATP transporter. Altogether, characterization of the transporters involved in the flux of H2-GMZ provides insight into the selectivity of drug disposition across the human BTB to understand and overcome the pharmacokinetic and pharmacodynamic difficulties presented by this barrier. SIGNIFICANCE STATEMENT: Despite major advancements in female contraceptives, male alternatives, including vasectomy, condom usage, and physical withdrawal, are antiquated and the widespread availability of nonhormonal, reversible chemical contraceptives is nonexistent. Indazole carboxylic acid analogs such as H2-GMZ are promising new reversible, antispermatogenic drugs that are highly effective in rodents. This study characterizes the carrier-mediated processes that permit H2-GMZ and other drugs to enter Sertoli cells and the observations made here will guide the development of drugs that effectively circumvent the BTB.

Data on comparative proteomic profiling of human sperm affected by 4-tert-octylphenol in vitro

This data article presents proteomic profiling and posttranslational modifications of sperm proteins relating to the research paper “4-tert-octylphenol injures motility and viability of human sperm by affecting cAMP-PKA/PKC-tyrosine phosphorylation signals.” (Huang et al., 2018). Comparative proteomics was applied to identify the target biomarkers and the relevant molecular events of human sperm which were exposed to 0 (Dimethyl sulfoxide, DMSO), 0.1, or 0.3 mM 4-tert-octylphenol (4t-OP) for two hours in vitro. All differentially expressed (DE) proteins were then mapped to the human sperm proteome 2.0 (Wang et al., 2016) to clarify the posttranslational modifications (PTMs) of the DE proteins. We provide the associated mass spectrometry raw files; the PTMs in all the DE proteins, in DE proteins related to apoptosis, and in DE proteins related to motility. These data highlight the molecular mechanism relating to injured motility and viability of human sperm affected by 4t-OP.

4-tert-octylphenol injures motility and viability of human sperm by affecting cAMP-PKA/PKC-tyrosine phosphorylation signals

4-tert-octylphenol (4t-OP) is a well-known xenoestrogen. Our objective was to explore the effects and molecular mechanisms of 4t-OP on human sperm. Sperm samples were exposed to 0, 0.1, or 0.3 mM 4t-OP for two hours. Results showed that both sperm viability and motility were significantly injured by 0.3 mM 4t-OP. We applied comparative proteomics to explore the molecular targets affected by 4t-OP. 81 differentially expressed (DE) proteins were identified. Bioinformatic analysis showed that these proteins were highly associated with motility and apoptosis, and were mostly enriched in cAMP-PKA/PKC-phosphorylation-associated pathway. We further verified that 0.1 mM and 0.3 mM 4t-OP significantly decreased cAMP activity of sperm. Expression of RACK1 and PRDX6 were detected by western blot (WB) to verify their tendencies in gels; antiapoptotic factor BCL2 was also detected by WB. The data indicated that 4-tert-octylphenol injures the motility and viability of human sperm probably by affecting cAMP-PKA/PKC-tyrosine phosphorylation signals.

In vitro study evaluating the instantaneous treatment of ozonised olive oil on human sperm

OBJECTIVE

The aim of our study was to evaluate the effects of ozonised olive oil (OOO) on human sperm in vitro.

METHODS

Human sperm was incubated with OOO for 20 s in vitro. The lowest concentration that completely immobilised all the sperm in 20 s without subsequent recovery of motility was recorded as the minimum effective concentration (MEC). The effects of OOO at MEC on human sperm viability, mitochondrial and acrosomal status, DNA integrity and transmission electron microscopy were observed.

RESULTS

Our findings demonstrate that OOO dose-dependently inhibits sperm motility. The MEC of OOO for 100% sperm immobilisation in 20 s was 6 μg/ml. Further experiments showed that sperm ultrastructure, function and DNA integrity were significantly affected after treatment with 6 μg/ml OOO in vitro.

CONCLUSIONS

OOO has spermicidal potential and may be explored as a promising vaginal contraceptive agent.

Low mitochondrial activity within developing earthworm male germ-line cysts revealed by JC-1

The male germ-line cysts that occur in annelids appear to be a very convenient model for spermatogenesis studies. Germ-line cysts in the studied earthworm are composed of two compartments: (1) germ cells, where each cell is connected via one intercellular bridge to (2) an anuclear central cytoplasmic mass, the cytophore. In the present paper, confocal and transmission electron microscopy were used to follow the changes in the mitochondrial activity and ultrastructure within the cysts during spermatogenesis. JC-1 was used to visualize the populations of mitochondria with a high and low membrane potential. We used the spot detection Imaris software module to obtain the quantitative data. We counted and compared the 'mitochondrial spots' - the smallest detectable signals from mitochondria. It was found that in all of the stages of cyst development, the majority of mitochondria spots showed a green fluorescence, thus indicating a low mitochondrial membrane potential (MMP). Moreover, the number of active mitochondria spots that were visualized by red JC-1 fluorescence (high MMP) drastically decreased as spermatogenesis progressed. As much as 26% of the total number of mitochondrial spots in the spermatogonial cysts showed a high MMP - 19% in the spermatocytes, 24% in the isodiametric spermatids and 3% and 6%, respectively, in the cysts that were holding early and late elongate spermatids. The mitochondria were usually thread-like and had an electron-dense matrix and lamellar cristae. Then, during spermiogenesis, the mitochondria within both the spermatids and the cytophore had a tendency to form aggregates in which the mitochondria were cemented by an electron-dense material.

Male contraceptive Adjudin is a potential anti-cancer drug

Adjudin, also known as AF-2364 and an analog of lonidamine (LND), is a male contraceptive acting through the induction of premature sperm depletion from the seminiferous epithelium when orally administered to adult rats, rabbits or dogs. It is also known that LND can target mitochondria and block energy metabolism in tumor cells. However, whether Adjudin exhibits any anti-cancer activity remains to be elucidated. Herein we described the anti-proliferative activity of Adjudin on cancer cells in vitro and on lung and prostate tumors inoculated in nude mice. We found that Adjudin induced apoptosis in cancer cells through a Caspase-3-dependent pathway. Further experiments revealed that Adjudin could trigger mitochondrial dysfunction in cancer cells, apparently affecting the mitochondrial mass, inducing the loss of mitochondrial membrane potential and reducing cellular ATP levels. Intraperitoneal administration of Adjudin to tumor-bearing athymic nude mice also significantly suppressed the lung and prostate tumor growth. When used in combination with cisplatin, Adjudin enhances the sensitivity to cisplatin-induced cancer cell cytotoxicity. Taken together, these findings have demonstrated that Adjudin may be a potential drug for cancer therapy.