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Invasion or damage of the male reproductive system is one of the reported outcomes of viral infection. Current studies have documented that SARS-CoV-2, which causes COVID-19, can damage the male reproductive system in large part by inflammatory damage caused by a cytokine storm. However, whether SARS-CoV-2 can infect the human testis directly and enter semen is controversial. Other adverse effects of SARS-CoV-2 on male reproduction are also of concern and require comprehensive evaluation. Here, we analyze the invasiveness of SARS-CoV-2 in the testis and examine reported mechanisms by which SARS-CoV-2 interferes with male reproduction. Long-term implications of SARS-CoV-2 infection on male reproduction are also discussed. It should be emphasized that although COVID-19 may induce testicular damage, a substantial decrease in male reproductive capacity awaits clinical evidence. We propose that there is an urgent need to track male COVID-19 patients during their recovery. The development of suitable experimental models, including human reproductive organoids, will be valuable to further investigate the viral impact on reproduction for current and future pandemics.

During goat follicular development, abnormal expression of nuclear respiratory factor 1 (NRF1) in granulosa cells may drive follicular atresia with unknown regulatory mechanisms. In this study, we investigated the effects of NRF1 on steroidogenesis and cell apoptosis by overexpressing or silencing it in goat luteinized granulosa cells (LGCs). Results showed that knockdown of NRF1 expression significantly inhibited the expression of STAR and CYP19A1, which are involved in sex steroid hormones synthesis, and led to lower estrogen levels. Knockdown of NRF1 resulted in an increased percentage of apoptosis, probably due to the release of cytochrome c from mitochondria, accompanied by upregulating mRNA and protein levels of apoptosis-related markers BAX, caspase 3 and caspase 9. These data indicate that NRF1 might be related with steroidogenesis and cell apoptosis. Furthermore, NRF1 silence reduced mitochondrial transcription factor A (TFAM) transcription activity, mtDNA copy number and ATP level. Simultaneously, knockdown of NRF1 suppressed the transcription and translation levels of SOD, GPx and CAT, decreased glutathione level and increased 8-OHdG level. However, the overexpression of NRF1 in LGCs or gain of TFAM in NRF1 silenced LGCs increased the expression of genes involved in mitochondrial function and biogenesis, and elevated the antioxidant stress system and steroids synthesis. Taken together, aberrant expression of NRF1 could induce mitochondrial dysfunction and disturb the cellular redox balance, which lead to disturbance of steroid hormone synthesis, and trigger LGC apoptosis through the mitochondria-dependent pathway. These findings will be helpful for understanding the role of NRF1 in goat ovarian follicular development and atresia.

In this study, using a mouse model, we tested the hypothesis that restraint stress would impair the developmental potential of oocytes by causing oxidative stress and that antioxidant supplementation could overcome the adverse effect of stress-induced oxidative stress. Female mice were subjected to restraint stress for 24 h starting 24 h after equine chorionic gonadotropin injection. At the end of stress exposure, mice were either killed to recover oocytes for in vitro maturation (IVM) or injected with human chorionic gonadotropin and caged with male mice to observe in vivo development. The effect of antioxidants was tested in vitro by adding them to IVM medium or in vivo by maternal injection immediately before restraint stress exposure. Assays carried out to determine total oxidant and antioxidant status, oxidative stress index, and reactive oxygen species (ROS) and glutathione levels indicated that restraint stress increased oxidative stress in mouse serum, ovaries, and oocytes. Whereas the percentage of blastocysts and number of cells per blastocyst decreased significantly in oocytes from restraint-stressed mice, addition of antioxidants to IVM medium significantly improved their blastocyst development. Supplementation of cystine and cysteamine to IVM medium reduced ROS levels and aneuploidy while increasing glutathione synthesis and improving pre- and postimplantation development of oocytes from restraint-stressed mice. Furthermore, injection of the antioxidant epigallocatechin gallate into restraint-stressed mice significantly improved the blastocyst formation and postimplantation development of their oocytes. In conclusion, restraint stress at the oocyte prematuration stage impaired the developmental potential of oocytes by increasing oxidative stress and addition of antioxidants to IVM medium or maternal antioxidant injection overcame the detrimental effect of stress-induced oxidative stress. The data reported herein are helpful when making attempts to increase the chances of a successful outcome in human IVF, because restraint was applied at a stage similar to the FSH stimulation period in a human IVF program.

Embryo implantation is a crucial step for the successful establishment of mammalian pregnancy. Cyclophilin A (CYPA) is a ubiquitously expressed intracellular protein and is secreted in response to inflammatory stimuli to regulate diverse cellular functions. However, there are currently no reports about the role of CYPA in embryo implantation. Here, we examine the expression pattern of CYPA during mouse early pregnancy and explore the potential role of CYPA during implantation. CYPA is expressed in the subluminal stroma surrounding the implanting blastocyst on day 5 of pregnancy, but not at inter-implantation sites. In ovariectomized mice, estrogen and progesterone significantly stimulate CYPA expression. When pregnant mice are injected intraperitoneally with CYPA inhibitor, the numbers of implantation sites are significantly reduced. Using an in vitro stromal cell culture system, Ppia siRNA knockdown of CYPA and CYPA-specific inhibitor treatment partially inhibits levels of CD147, MMP3 and MMP9. Decreased CYPA expression also significantly inhibits Stat3 activity and expands estrogen responsiveness. Taken together, CYPA may play an important role during mouse embryo implantation.

Protein disulfide isomerase 3 (PDIA3) is a chaperone protein that modulates the folding of newly synthesized glycoproteins, has isomerase and redox activity, and has been implicated in the pathogenesis of many diseases. However, the role of PDIA3 in pregnancy-associated diseases remains largely unknown. Our present study reveals a key role for PDIA3 in the biology of placental trophoblasts from women with preeclampsia (PE). Immunohistochemistry and Western blot analysis revealed that PDIA3 expression was decreased in villous trophoblasts from women with PE compared to normotensive pregnancies. Further, using a Cell Counting Kit-8 assay, flow cytometry, and 5-ethynyl-2’-deoxyuridine (EdU) staining, we found that siRNA-mediated PDIA3 knockdown significantly promoted apoptosis and inhibited proliferation in the HTR8/SVneo cell line, while overexpression of PDIA3 reversed these effects. Furthermore, RNA sequencing and Western blot analysis demonstrated that knockdown of PDIA3 inhibited MDM2 protein expression in HTR8 cells, concurrent with marked elevation of p53 and p21 expression. Conversely, overexpression of PDIA3 had the opposite effects. Immunohistochemistry and Western blot further revealed that MDM2 protein expression was downregulated and p21 was increased in trophoblasts of women with PE compared to women with normotensive pregnancies. Our findings indicate that PDIA3 expression is decreased in the trophoblasts of women with PE, and decreased PDIA3 induces trophoblast apoptosis and represses trophoblast proliferation through regulating the MDM2/p53/p21 pathway.

We recently reported that electrical activation followed by secondary chemical activation greatly enhanced the developmental competence of in vitro matured porcine oocytes fertilized by intracytoplasmic sperm injection (ICSI). We hypothesized that sperm treatment with disulfide bond reducing agents will enhance the development competence of porcine embryos produced by this ICSI procedure. We examined the effects of glutathione (GSH), dithiothreitol (DTT), GSH or DTT in combination with heparin on sperm DNA structure, paternal chromosomal integrity, pronuclear formation, and developmental competence of in vitro matured porcine oocytes after ICSI. Acridine orange staining and flow cytometry based sperm chromatin structure assay were used to determine sperm DNA integrity by calculating the cells outside the main population (COMP αT). No differences were observed in COMP αT values among GSH-treated and control groups. COMP αT values in GSH-treated groups were significantly lower than that in DTT-treated groups. Following ICSI, GSH treatments did not significantly alter paternal chromosomal integrity. Paternal chromosomal integrity in sperm treated with DTT plus or minus heparin was also the lowest among all groups. GSH-treated sperm yielded the highest rates of normal fertilization and blastocyst formation, which were significantly higher than that of control and DTT-treated groups. The majority of blastocysts derived from control and GSH-treated spermatozoa were diploid, whereas blastocysts derived from DTT-treated spermatozoa were haploid. In conclusion, sperm treatment with GSH enhanced the developmental capacity of porcine embryos produced by our optimized ICSI procedure.

Long ncRNAs regulate a complex array of fundamental biological processes, while its molecular regulatory mechanism in Leydig cells (LCs) remains unclear. In the present study, we established the lncRNA LOC102176306/miR-1197-3p/peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PPARGC1A) regulatory network by bioinformatic prediction, and investigated its roles in goat LCs. We found that lncRNA LOC102176306 could efficiently bind to miR-1197-3p and regulate PPARGC1A expression in goat LCs. Downregulation of lncRNA LOC102176306 significantly supressed testosterone (T) synthesis and ATP production, decreased the activities of antioxidant enzymes and mitochondrial complex I and complex III, caused the loss of mitochondrial membrane potential, and inhibited the proliferation of goat LCs by decreasing PPARGC1A expression, while these effects could be restored by miR-1197-3p inhibitor treatment. In addition, miR-1197-3p mimics treatment significantly alleviated the positive effects of lncRNA LOC102176306 overexpression on T and ATP production, antioxidant capacity and proliferation of goat LCs. Taken together, lncRNA LOC102176306 functioned as a sponge for miR-1197-3p to maintain PPARGC1A expression, thereby affecting the steroidogenesis, cell proliferation and oxidative stress of goat LCs. These findings extend our understanding of the molecular mechanisms of T synthesis, cell proliferation and oxidative stress of LCs.

Preeclampsia is a gestational hypertensive disease; however, preeclampsia remains poorly understood. Bioinformatics analysis was applied to find novel genes involved in the pathogenesis of preeclampsia and identified CLDN1 as one of the most differentially expressed genes when comparing patients with preeclampsia and healthy controls. The results of the qRT-PCR, Western blotting and immunohistochemistry experiments demonstrated that CLDN1 was significantly downregulated in the chorionic villi in samples from patients with preeclampsia. Furthermore, knockdown of CLDN1 in HTR-8/SVneo cells resulted in the inhibition of proliferation and induction of apoptosis, and overexpression of CLDN1 reversed these effects. In addition, RNA-seq assays demonstrated that the gene BIRC3 is potentially downstream of CLDN1 and is involved in the regulation of apoptosis. Knockdown of CLDN1 confirmed that the expression level of BIRC3 was obviously decreased and was associated with a significant increase in cleaved PARP. Interestingly, the apoptotic effect in CLDN1 knockdown cells was rescued after BIRC3 overexpression. Overall, these results indicate that a decrease in CLDN1 inhibits BIRC3 expression and increases cleaved PARP levels thus participating in the pathogenesis of preeclampsia.