Developmental Programming: Prenatal Testosterone Excess on Liver and Muscle Coding and Noncoding RNA in Female Sheep

Exploratory analysis of differences at the transcriptional interface between the maternal and fetal compartments of the sheep placenta and potential influence of fetal sex

An understanding of the inner workings of the placenta is imperative to elucidate how the maternal and fetal compartments coordinate to mediate fetal development. The two compartments can be separated and studied before term in sheep, a feat not possible in humans, thus providing a valuable translational model. This study investigated differential expression of gene signaling networks in the maternal and fetal compartments of the placenta and explored the potential influence of fetal sex. On approximately gestational day 120 (term: 147 days), ewes were euthanized and fetuses removed and sexed. Placentomes [n = 5 male, n = 3 female] were collected, and caruncles (maternal) and cotyledons (fetal) were separated and sequenced to assess RNA expression. Analysis revealed 2627 differentially expressed genes (FDR<0.01, abslog2FC ≥ 2) contributing to key transcriptional differences between maternal and fetal compartments, which suggested that the maternal compartment drives extracellular signaling at the interface whereas the fetal compartment controls internal mechanisms crucial for fetal-placental development. X-chromosome inactivation equalized expression of a vast majority of X-linked genes in the fetal compartment. Additionally, the female placenta had more fine-tuned regulation of key pathways for fetal-placental development, such as DNA replication, mRNA surveillance, and RNA transport, compared to males, which had enrichment of metabolic pathways including TCA cycle and galactose metabolism. These findings, in addition to supporting differences in expression in the maternal and fetal placental compartments and the possible influence of fetal sex, offer a transcriptional platform to compare placental perturbations that occur at the maternal-fetal interface that contribute to adverse pregnancy outcomes.

Developmental programming: Sex-specific effects of prenatal exposure to a real-life mixture of environmental chemicals on liver function and transcriptome in sheep

Humans are chronically exposed to a mixture of environmental chemicals (ECs), many with metabolic and endocrine disrupting potential, contributing to non-communicable disease burden. Understanding the effects of chronic exposure to low-level mixtures of ECs requires an animal model that reflects real-world conditions, lags behind studies on single ECs. Biosolids, from wastewater treatment, offers a real-life model to investigate the developmental health risks from EC mixtures. Prenatal biosolids exposure studies have documented metabolic perturbations including heavier thyroid glands in male fetuses and reduced bodyweight in prepubertal male lambs followed by catchup growth. We hypothesized that maternal preconceptional and gestational exposure of sheep to biosolids programs sex-specific transcriptional and functional changes in the offspring liver. Ewes (F0) were grazed on either inorganic fertilizer (C) or biosolids-treated pastures (BTP) preconception till parturition. All lambs (n = 15/group with male n = 7/group and females n = 8/group) were raised on Control pastures until euthanasia at 9.5 weeks. Next generation sequencing of liver RNA and DESeq2 was used to identify exposure-specific differentially expressed genes (DEG) and sex-differentially expressed genes (SDG). Liver function was assessed with markers of oxidative stress, triglyceride and fibrosis markers. Control lambs exhibited 647 SDGs confirming the inherent sexual dimorphism in hepatic gene expression. A sex-stratified analysis identified 10 DEG, mostly affecting metabolism, in male and none in female lambs. Biosolids exposure diminished the sexual dimorphism in hepatic gene expression barring 41 genes, potentially due to the increase in androgenic steroids found in F0 maternal circulation. Additionally, BTP male lambs showed elevated plasma triglyceride and a trend towards increased liver triglyceride concentrations. The identified effects of prenatal exposure to low-dose mixture of ECs via biosolids, in a precocial species paralleling human developmental patterns holds translational importance for understanding the sexually dimorphic origin of non-communicable diseases.

Developmental programming: Testosterone excess masculinizes female pancreatic transcriptome and function in sheep

Hyperandrogenic disorders, such as polycystic ovary syndrome, are often associated with metabolic disruptions such as insulin resistance and hyperinsulinemia. Studies in sheep, a precocial model of translational relevance, provide evidence that in utero exposure to excess testosterone during days 30-90 of gestation (the sexually dimorphic window where males naturally experience elevated androgens) programs insulin resistance and hyperinsulinemia in female offspring. Extending earlier findings that adverse effects of testosterone excess are evident in fetal day 90 pancreas, the end of testosterone treatment, the present study provides evidence that transcriptomic and phenotypic effects of in utero testosterone excess on female pancreas persist after cessation of treatment, suggesting lasting organizational changes, and induce a male-like phenotype in female pancreas. These findings demonstrate that the female pancreas is susceptible to programmed masculinization during the sexually dimorphic window of fetal development and shed light on underlying connections between hyperandrogenism and metabolic homeostasis.

Bisphenol A interferes with lncRNA Fhadlos2 and RUNX3 association in adolescent mouse ovary

Bisphenol A (BPA) has a number of adverse effects on the reproductive development of females. In particular, the mechanism of disruption of ovarian development in adolescent mice is still unclear. Based on transcriptome sequencing results, a differentially expressed lncRNA, Fhad1os2, was detected in the ovaries of BPA-exposed pubertal mice. In our study, the lncRNA Fhad1os2, localized in the ovarian granulosa cell cytoplasm, could regulate the proliferation of mouse ovarian granulosa cells. Mechanistically, the results of RNA pull-down experiments as well as mass spectrometry analysis showed that ERα, an interfering signaling molecule of BPA, could directly bind lncRNA Fhad1os2 and decrease the transcription of lncRNA Fhad1os2 in response to the estrogen-like effect of BPA. BPA exposure also caused abnormal lncRNA Fhad1os2 pulldown protein-related signaling pathways in the ovaries of adolescent mice. Furthermore, lncRNA Fhad1os2 interacted with RUNX3, a transcription factor related to follicle development and hormone synthesis. As a negative regulator, lncRNA Fhad1os2 transactivated the expression of Runx3, which in turn induced RUNX3 to positively regulate aromatase (Cyp19a1) expression in mouse ovarian granulosa cells and promote estrogen synthesis. In conclusion, our study indicates that BPA exposure interferes with ERα-regulated lncRNA Fhad1os2 interactions with RUNX3 in pubertal mice, affecting estrogen synthesis in mouse granulosa cells and contributing to premature ovarian maturation in pubertal mice.

Genes in loci genetically associated with polycystic ovary syndrome are dynamically expressed in human fetal gonadal, metabolic and brain tissues

Background

Polycystic ovary syndrome (PCOS) is a heterogeneous disorder, affecting around 10% of women of reproductive age, with infertility, depression or anxiety, obesity, insulin resistance and type 2 diabetes as risk factors. The cause of PCOS is not known but there is a predisposition to developing PCOS in adult life that arises during fetal or perinatal life. PCOS also has a genetic predisposition and a number of genetic loci associated with PCOS have been identified. These loci contain 25 candidate genes which are currently being studied to define the syndrome. Although the name PCOS suggests a syndrome of the ovary, PCOS has also been associated with the central nervous system and other organ systems in the body due to the wide variety of symptoms it presents.

Methods

Here, we examined the expression patterns of PCOS candidate genes in gonadal (ovary and testis), metabolic (heart, liver and kidney) and brain (brain and cerebellum) tissues during the first half of human fetal development and postnatally until adulthood using public RNA sequencing data. This study is an initial step for more comprehensive and translational studies to define PCOS.

Results

We found that the genes were dynamically expressed in the fetal tissues studied. Some genes were significantly expressed in gonadal tissues, whilst others were expressed in metabolic or brain tissues at different time points prenatally and/or postnatally. HMGA2, FBN3 and TOX3 were highly expressed during the early stages of fetal development in all tissues but least during adulthood. Interestingly, correlation between expression of HMGA2/YAP1 and RAD50/YAP1 were significant in at least 5 of the 7 fetal tissues studied. Notably, DENND1A, THADA, MAPRE1, RAB5B, ARL14EP, KRR1, NEIL2 and RAD50 were dynamically expressed in all postnatal tissues studied.

Conclusions

These findings suggest that these genes have tissue- or development-specific roles in multiple organs, possibly resulting in the various symptoms associated with PCOS. Thus the fetal origin of a predisposition to PCOS in adulthood could arise via the effects of PCOS candidate genes in the development of multiple organs.

Developmental programming: adverse sexually dimorphic transcriptional programming of gestational testosterone excess in cardiac left ventricle of fetal sheep

Adverse in-utero insults during fetal life alters offspring's developmental trajectory, including that of the cardiovascular system. Gestational hyperandrogenism is once such adverse in-utero insult. Gestational testosterone (T)-treatment, an environment of gestational hyperandrogenism, manifests as hypertension and pathological left ventricular (LV) remodeling in adult ovine offspring. Furthermore, sexual dimorphism is noted in cardiomyocyte number and morphology in fetal life and at birth. This study investigated transcriptional changes and potential biomarkers of prenatal T excess-induced adverse cardiac programming. Genome-wide coding and non-coding (nc) RNA expression were compared between prenatal T-treated (T propionate 100 mg intramuscular twice weekly from days 30 to 90 of gestation; Term: 147 days) and control ovine LV at day 90 fetus in both sexes. Prenatal T induced differential expression of mRNAs in the LV of female (2 down, 5 up) and male (3 down, 1 up) (FDR < 0.05, absolute log2 fold change > 0.5); pathways analysis demonstrated 205 pathways unique to the female, 382 unique to the male and 23 common pathways. In the male, analysis of ncRNA showed differential regulation of 15 lncRNAs (14 down, 1 up) and 27 snoRNAs (26 down and 1 up). These findings suggest sexual dimorphic modulation of cardiac coding and ncRNA with gestational T excess.