Sex differences in embryonic gonad transcriptomes and benzo[a]pyrene metabolite levels after transplacental exposure

Polycyclic aromatic hydrocarbons like benzo[a]pyrene (BaP) are generated during incomplete combustion of organic materials. Prior research has demonstrated that BaP is a prenatal ovarian toxicant and carcinogen. However, the metabolic pathways active in the embryo and its developing gonads and the mechanisms by which prenatal exposure to BaP predisposes to ovarian tumors later in life remain to be fully elucidated. To address these data gaps, we orally dosed pregnant female mice with BaP from E6.5-11.5 (0, 0.2 or 2 mg/kg-day) for metabolite measurement or E9.5-11.5 (0 or 3.33 mg/kg-day) for embryonic gonad RNA-sequencing. Embryos were harvested at E13.5 for both experiments. The sum of BaP metabolite concentrations increased significantly with dose in the embryos and placentas, and concentrations were significantly higher in female than male embryos and in embryos than placentas. RNA sequencing revealed that enzymes involved in metabolic activation of BaP are expressed at moderate to high levels in embryonic gonads and that greater transcriptomic changes occurred in the ovaries in response to BaP than in the testes. We identified 490 differentially expressed genes (DEGs) with FDR p-values <0.05 when comparing BaP-exposed to control ovaries, but no statistically significant DEGs between BaP-exposed and control testes. Genes related to monocyte/macrophage recruitment and activity, prolactin family genes, and several keratin genes were among the most upregulated genes in the BaP-exposed ovaries. Results show that developing ovaries are more sensitive than testes to prenatal BaP exposure, which may be related to higher concentrations of BaP metabolites in female embryos.

Polyubiquitin gene Ubb is required for upregulation of Piwi protein level during mouse testis development

Testis development, including early embryonic gonad formation and late postnatal spermatogenesis, is essential for the reproduction of higher metazoans to generate fertile gametes, called sperm. We have previously reported that the polyubiquitin gene Ubb is required for fertility in both male and female mice. In particular, the Ubb-null male mice showed an azoospermia phenotype due to arrest of spermatogenesis at the pachytene stage. Here, we analyzed the whole testis proteome at postnatal day 20 to define the molecular mediators of the male-infertility phenotype caused by Ubb knockout. From the identified proteome, 564 proteins were significantly and differentially expressed in Ubb-knockout testes and, among these, 36 downregulated proteins were involved at different stages of spermatogenesis. We also found that levels of piRNA metabolic process-related proteins, including Piwil2 and Tdrd1, were downregulated in Ubb-null testes through functional gene ontology analysis. Further, protein–protein interaction mapping revealed that 24 testis development-related proteins, including Hsp90aa1, Eef1a1, and Pabpc1, were directly influenced by the depletion of ubiquitin. In addition, the reduced mRNA levels of these proteins were observed in Ubb-knockout testes, which closely resembled the global downregulation of piRNA-metabolic gene expression at the transcriptional and post-transcriptional levels. Together with proteomic and transcriptional analyses, our data suggest that Ubb expression is essential for the maintenance of testicular RNA-binding regulators and piRNA-metabolic proteins to complete spermatogenesis in mice.

Choriocarcinoma metastatic to the skin: A rare occurrence associated with dismal outcome

Germ cell tumors (GCTs) are a histologically heterogeneous group of tumors that arise from the primitive germ cell of the embryonic gonad. Choriocarcinoma is a variant of GCTs that is prone to hematogenous metastasis to the liver, lung, and brain. Cutaneous metastasis in choriocarcinoma is rarely encountered with only a few cases reported in literature. We report the case of a 28-year-old male presenting with lower back pain that, upon further work-up, was diagnosed with pure choriocarcinoma of the testes. Around 9 months after his initial presentation, he developed a cutaneous back lesion. Microscopic examination confirmed the presence of choriocarcinoma composed of mononuclear cytotrophoblasts which interweave with multinucleated syncytiotrophoblasts. The patient passed away 3 weeks after the onset of cutaneous metastasis.

Primordial germ cells profiles incubated for 24 hours in phosphate buffer saline [-] solution

Gonadal development is a sequential process that can be divided into three major events: the PGCs migration, sex determination and gonadal differentiation. This study was aimed to see the development of PGCs isolated from the gonads of embryos after being incubated for 7 days and then was incubated using a solution of Phosphate Buffer Saline (PBS) [-]. The developing gonad can be isolated from 7 days old chick and can be incubated at a temperature of 37.8^oC in a solution of PBS [-]: without Ca2+ and Mg2+. The release of gonadal PGC was observed within 1, 8, 16, and 24 hours after the embryonic gonad was placed in a PBS solution [-]. The results showed that PGCs can be separated from gonadal tissues and can be collected by entering the developing gonad to the PBS [-] solution. The highest percentage of PGCs and survival rate was obtained after gonad was incubated for 1 hour and was not different with 8 hours (P>0.05). Those result was significantly different (P<0.05) with the 16 and 24 hours incubation. The highest purity rate percentage was in the 8 hours incubation, but did not show a significant difference (P>0.05) with the 1 and 16 hours incubation. The percentage of the purity differed (P<0.05) after the 24 hours incubation. It can be concluded that the most appropriate incubation time to obtain PGCs from the KUB chicken embryonic gonad is no more than 8 hours.