Implications of miRNA expression pattern in bovine oocytes and follicular fluids for developmental competence

Developmental competence determines the oocyte capacity to support initial embryo growth, but the molecular mechanisms underlying this phenomenon are still ill-defined. Changes in microRNA (miRNA) expression pattern have been described during follicular growth in several species. Therefore, aim of this study was to investigate whether miRNA expression pattern in cow oocyte and follicular fluid (FF) is associated with the acquisition of developmental competence. Samples were collected from ovaries with more than, or fewer than, 10 mid-antral follicles (H- and L-ovaries) because previous studies demonstrated that this parameter is a reliable predictor of oocyte competence. After miRNA deep sequencing and bioinformatic data analysis, we identified 58 miRNAs in FF and 6 in the oocyte that were differentially expressed between H- and L-ovaries. Overall, our results indicate that miRNA levels both in FF and in the ooplasm must remain within specific thresholds and that changes in either direction compromising oocyte competence. Some of the miRNAs found in FF (miR-769, miR-1343, miR-450a, miR-204, miR-1271 and miR-451) where already known to regulate follicle growth and their expression pattern indicate that they are also involved in the acquisition of developmental competence. Some miRNAs were differentially expressed in both compartments but with opposite patterns, suggesting that miRNAs do not flow freely between FF and oocyte. Gene Ontology analysis showed that the predicted gene targets of most differentially expressed miRNAs are part of a few signalling pathways. Regulation of maternal mRNA storage and mitochondrial activity seem to be the processes more functionally relevant in determining oocyte quality. In conclusion, our data identified a few miRNAs in the follicular fluid and in the ooplasm that modulate the oocyte developmental competence. This provides new insights that could help with the management of cattle reproductive efficiency

Maternal exposure to di(2-ethylhexyl)phthalate (DEHP) promotes the transgenerational inheritance of adult-onset reproductive dysfunctions through the female germline in mice

Endocrine disruptors (EDS) are compounds known to promote transgenerational inheritance of adult-onset disease in subsequent generations after maternal exposure during fetal gonadal development. This study was designed to establish whether gestational and lactational exposure to the plasticizer di(2-ethylhexyl)phthalate (DEHP) at environmental doses promotes transgenerational effects on reproductive health in female offspring, as adults, over three generations in the mouse. Gestating F0 mouse dams were exposed to 0, 0.05, 5 mg/kg/day DEHP in the diet from gestational day 0.5 until the end of lactation. The incidence of adult-onset disease in reproductive function was recorded in F1, F2 and F3 female offspring. In adult Fl females, DEHP exposure induced reproductive adverse effects with: i) altered ovarian follicular dynamics with reduced primordial follicular reserve and a larger growing pre-antral follicle population, suggesting accelerated follicular recruitment; ii) reduced oocyte quality and embryonic developmental competence; iii) dysregulation of the expression profile of a panel of selected ovarian and pre-implantation embryonic genes. F2 and F3 female offspring displayed the same altered reproductive morphological phenotype and gene expression profiles as Fl, thus showing transgenerational transmission of reproductive adverse effects along the female lineage. These findings indicate that in mice exposure to DEHP at doses relevant to human exposure during gonadal sex determination significantly perturbs the reproductive indices of female adult offspring and subsequent generations. Evidence of transgenerational transmission has important implications for the reproductive health and fertility of animals and humans, significantly increasing the potential biohazards of this toxicant

Exposure to di(2-ethyl-hexyl) phthalate (DEHP) in utero and during lactation causes long-term pituitary-gonadal axis disruption in male and female mouse offspring

The present study examined the effects in mice of exposure to di(2-ethyl-hexyl) phthalate (DEHP) throughout pregnancy and lactation on the development and function of the pituitary-gonadal axis in male and female offspring once they have attained adulthood. Groups of two to three dams were exposed with the diet from gestational d 0.5 until the end of lactation, at 0, 0.05, 5, and 500 mg DEHP/kg \ub7 d. The experiment was repeated three times (total: seven to 10 dams per treatment). The 500-mg dose caused complete pregnancy failure, whereas exposure to doses of 0.05 and 5 mg did not affect pregnancy and litter size. In total, about 30 male and 30 female offspring per group were analyzed. Offspring of the DEHP-treated groups, compared with controls, at sexual maturity showed: 1) lower body weight (decrease 20-25%, P < 0.001); 2) altered gonad weight (testes were 3c13% lighter and ovaries 3c40% heavier; P < 0.001); 3) poor germ cell quality (semen was 3c50% less concentrated and 20% less viable, and 3c10% fewer oocytes reached MII stage, P < 0.001); 4) significant lower expression of steroidogenesis and gonadotropin-receptor genes in the gonads; and 5) up-regulated gonadotropin subunit gene expression in the pituitary. In conclusion, our findings suggest that, in maternally exposed male and female mice, DEHP acts on multiple pathways involved in maintaining steroid homeostasis. Specifically, in utero and lactational DEHP exposure may alter estrogen synthesis in both sexes. This, in turn, induces dysregulation of pituitary-gonadal feedback and alters the reproductive performance of exposed animals

Effects of polychlorinated biphenyls in Cd-1 mice : reproductive toxicity and intergenerational transmission

Several studies indicate that in-utero and peri-natal exposure to polychlorinated biphenyls (PCBs) induces adverse reproductive effects but it remains unclear whether such effects may be transmitted to subsequent generations. We therefore investigated the association between maternal exposure to PCBs and reproductive health in male and female offspring over three generations.Mouse dams were fed 0, 1, 10, 100 \u3bcg/kg/day of a PCB mixture (101+118) during pregnancy and lactation. PCB levels were measured in the tissues of both dams and offspring.PCB concentrations at all doses investigated were greater in the offspring than in the dams (P 640.0001) confirming that the progeny were exposed as a result of maternal exposure. In F1 offspring, exposure to PCBs resulted in reductions in: i) testis weight (P 640.05) and seminiferous tubule diameter (P 640.05); ii) sperm viability (P 640.0001) and developmental capacity (P 640.05); iii) ovary weight (P 640.05); iv) oocyte developmental capacity (P 640.05), and in v) increased follicular atresia (P 640.0001).In females, adverse effects were observed only in the F1 animals. In contrast, male offspring exhibited reduced sperm viability and altered seminiferous tubule distribution up to the third generation, showing intergenerational transmission.In summary, our data indicate that exposure to PCBs at the time of gonadal sex determination perturbed, significantly, the reproductive physiology of male and female offspring in adulthood. Furthermore, male reproductive deficiencies may be observed in at least two further generations. These findings have significant implications for reproductive health and fertility of animals and humans

EFFECTS OF IN UTERO AND LACTATIONAL EXPOSURE TO DI(2-ETHYL-HEXYL) PHTHALATE (DEHP) AND POLYCHLORINATED BIPHENYLS (PCBS) IN MICE: REPRODUCTIVE TOXICITY AND MULTIGENERATIONAL TRANSMISSION

Several studies indicate that in utero and peri-natal exposure to some classes of endocrine disruptors induces adverse reproductive effects, but it remains unclear whether such effects may be transmitted to subsequent generations. The present study examined the effects in mice of exposure to di(2-ethyl-hexyl) phthalate (DEHP) or to polychlorinated biphenyls (PCBs) throughout pregnancy and lactation on reproductive health in male and female offspring, at adult age, over three generations. Groups of two to three dams were exposed to increasing doses of contaminants with the diet from gestational day 0.5 until the end of lactation. The doses employed were within the range of environmental exposure levels in humans (DEHP: 0, 0.05, 5, and 500 mg/kg/day; PCBs 101+118: 0, 1, 10, 100 \u3bcg/kg/day). In DEHP experiments, treatment of pregnant F0 dams with the 500 mg dose caused complete pregnancy failure, while a slight reduction in litter size in the 5 mg was observed. Male and female F1 offspring born from dams treated with 0.05 and 5 DEHP doses showed, once they reach adult age, significant morphological and functional alterations of the reproductive system. Specifically: i) lower body weight; ii) altered gonad weight (i.e.: lighter testis and heavier ovary) and morphology; iii) reduced germ cells quality; iv) low expression of steroidogenesis and gonadotropin-receptor genes in the gonads; and v) up-regulated gonadotropin subunits gene expression in the pituitary. DEHP exposure altered morphological and reproductive indices in male offspring only in the first generation. Conversely, F2 and F3 female offspring exhibited altered gonad weight and morphology, concomitantly with poor embryo quality, similarly to what observed in F1, thus showing a transgenerational transmission of reproductive adverse effects. Interestingly, also disregulation of selected ovarian and embryonic genes was maintained up to the third generation. In PCBs experiments, treatment did not affect F0 dams\u2019 reproductive outcome. Nevertheless, whole-body PCB burden increased in a dose-dependent manner confirming the effectiveness of the treatment. Furthermore, concentrations at all doses investigated were greater in the offspring than in the dams, confirming that the progeny were exposed as a result of maternal exposure. Pre- and peri-natal exposure to PCBs resulted in male and female offspring showing significant reproductive abnormalities, at adult age. Specifically, compared to controls, they showed reductions in: i) testis weight and seminiferous tubule diameter; ii) sperm viability and developmental capacity; iii) ovary weight; iv) oocyte developmental capacity. Furthermore, F1 ovaries showed a dose-dependent increase in follicular atresia, associated with down-regulation of cyp19a1 and pten mRNA levels. PCBs adverse reproductive effects in females were limited to F1 generation. In contrast, male offspring exhibited reduced sperm viability and altered seminiferous tubule distribution up to the third generation. These results evidence that maternal exposure to PCBs can affects reproductive health in multiple generations. In conclusion, our data indicate that exposure to the endocrine disruptors DEHP or PCBs, at the time of gonadal sex determination, perturbed significantly the reproductive indices of male and female adult offspring. Furthermore, some of the reproductive deficiencies observed upon direct exposure have been observed up to the third generation. These findings have significant implications for reproductive health and fertility of animals and humans

An easy approach to 1-silylated ketones and asymmetrical 1,6- and 1,8-dicarbonyl compounds

A variety of 1-silylated ketones and asymmetrical 1,6- and 1,8-dicarbonyl compounds are synthesized with 70-85% yields by means of Pd-catalysed selective hydrogenation reactions of the corresponding unsaturated conjugated products, readily available by a previously reported procedure

Di(2-ethylhexyl) Phthalate (DEHP) Impairs Female Fertility and Promotes Adipogenesis in C3H/N Mice

Background: Di(2-ethylhexyl) phthalate (DEHP) and its metabolites are known to affect lipid metabolism and adipogenesis, mainly by activation of PPARs. Exposure to DEHP has been linked with testicular impairment and male subfertility. However, the effects of DEHP on female reproductive health and metabolism remain to be studied in detail. Objectives: Analysis of dietary DEHP exposure on metabolism and fertility in female mice. Methods: In two independent approaches, female C3H/N mice were exposed via their diet to DEHP [0.05, 5, 500 mg/kg bw/day] for 8 weeks. Food intake, weight gain and litter size were recorded. After exposure, liver, visceral fat, and plasma were analyzed by qRTPCR and ELISA in F0 females (Study I) and F0 dams and their F1 offspring (Study II). Results: In Study I, F0 females had a significant increase in body weight, food intake, and visceral adipose tissue in all exposure groups compared with controls. In liver tissue, PPAR\u3b1 and PPAR\u3b3 transcripts were significantly changed in the 500mg group. In the same group, PPAR\u3b3 mRNA was significantly reduced in liver but not in fat tissue. Leptin and FABP4 mRNA were increased in adipose tissue, while adiponectin was decreased. In Study II, we detected a 100% abortion rate in F0 dams in the 500mg group. F1 offspring exposed in utero and during lactation had an increase in visceral fat tissue and body weight. Conclusion: DEHP impaired fertility in high concentrations and increased body weight and visceral fat depots in female C3H/N mice in environmentally relevant dosages. Although DEHP exposure was only in utero and during lactation, metabolic changes induced by DEHP did also occur in the offspring of diet-exposed females