Cre-LoxP and tamoxifen-induced deletion of ovarian quiescin sulfhydryl oxidase 2 showed disruption of ovulatory activity in mice.

BACKGROUND: Quiescin sulfhydryl oxidase 2 (QSOX2) is a flavin adenine dinucleotide-dependent sulfhydryl oxidase that is known to be involved in protein folding, cell growth regulation, and redox state modification through oxidative activities. Earlier studies demonstrated the tissue and cellular localization of QSOX2 in the male reproductive tract, as well as the highly-regulated mechanism of QSOX2 protein synthesis and expression through the coordinated action of testosterone and epididymal-enriched amino acid, glutamate. However, the presence and the functions of QSOX2 in female reproduction are unknown. In this study, we applied the Cre-loxP gene manipulation system to generate the heterozygous and homozygous Qsox2 knockout mice and examined its effects on ovarian function. RESULTS: We demonstrated that QSOX2 was detected in the follicle-supporting cells (granulosa and cumulus cells) of ovarian follicles of all stages but was absent in the corpus luteum, suggesting its supportive role in folliculogenesis. In comparison with reproductive organogenesis in wild-type mice, there was no difference in testicular and epididymal structure in male Qsox2 knockout; however, Qsox2 knockout disrupted the regular ovulation process in female mice as a drastic decrease in the formation of the corpus luteum was detected, and no pregnancy was achieved when mating males with homozygous Qsox2 knockout females. RNAseq analyses further revealed that Qsox2 knockout altered critical signaling pathways and genes that are responsible for maintaining ovarian functions. CONCLUSION: Our data demonstrated for the first time that Qsox2 is critical for ovarian function in mice.

Antioxidant Nanoparticles Restore Cisplatin-Induced Male Fertility Defects by Promoting MDC1-53bp1-Associated Non-Homologous DNA Repair Mechanism and Sperm Intracellular Calcium Influx.

Introduction: Cisplatin, a commonly used anticancer compound, exhibits severe off-target organ toxicity. Due to its wide application in cancer treatment, the reduction of its damage to normal tissue is an imminent clinical need. Cisplatin-induced testicular oxidative stress and damage lead to male sub- or infertility. Despite earlier studies showing that the natural polyphenol extracts honokiol serve as the free radical scavenger that reduces the accumulation of intracellular free radicals, whether honokiol exhibits direct effects on the testis and sperm is unclear. Thus, the aim of the current study is to investigate the direct effects of honokiol on testicular recovery and sperm physiology. Methods: We encapsulated this polyphenol antioxidation compound into liposome-based nanoparticles (nHNK) and gave intraperitoneally to mice at a dosage of 5 mg/kg body mass every other day for consecutive 6 weeks. Results: We showed that nHNK promotes MDC1-53bp1-associated non-homologous DNA double-strand break repair signaling pathway that minimizes cisplatin-induced DNA damage. This positive effect restores spermatogenesis and allows the restructuring of the multi-spermatogenic layers in the testis. By reducing mitochondrial oxidative damage, nHNK also protects sperm mitochondrial structure and maintains both testicular and sperm ATP production. By a yet-to-identify mechanism, nHNK restores sperm calcium influx at the sperm midpiece and tail, which is essential for sperm hypermotility and their interaction with the oocyte. Discussion: Taken together, the nanoparticulated antioxidant counteracts cisplatin-induced male fertility defects and benefits patients undertaking cisplatin-based chemotherapy. These data may allow the reintroduction of cisplatin for systemic applications in patients at clinics with reduced testicular toxicity.