Project description:Embryonic implantation comprises a dynamic and complicated series of events, which takes place only when the maternal uterine endometrium is in a receptive state. Blastocysts reaching the uterus communicate with the uterine endometrium to implant within a narrow time window. Interplay among various signalling molecules and transcription factors under the control of ovarian hormones is necessary for successful establishment of pregnancy. However, the molecular mechanisms that allow embryonic implantation in the receptive endometrium are still largely unknown. Here, we show that Sry-related HMG box gene-17 (Sox17) heterozygous mutant female mice exhibit subfertility due to implantation failure. Sox17 was expressed in the oviduct, uterine luminal epithelium, and blood vessels. Sox17 heterozygosity caused no appreciable defects in ovulation, fertilisation, blastocyst formation, and gross morphology of the oviduct and uterus. Another group F Sox transcription factor, Sox7, was also expressed in the uterine luminal and glandular epithelium relatively weakly. Despite uterine Sox7 expression, a significant reduction in the number of implantation sites was observed in Sox17 heterozygous mutant females due to haploinsufficiency. Our findings revealed a novel role of Sox17 in uterine receptivity to embryo implantation.
Project description:Health risk of human exposure to microcystin-leucine arginine (MC-LR) has aroused more and more attention over the past few decades. In the present study, MC-LR was orally administered to female mice at 0, 1, 10 and 40 ?g/L for three and six months. We found that chronic exposure to MC-LR at environmental levels could stimulate follicle atresia and lead to decreased developmental follicles, accompanied by a reduction of gonadosomatic index (GSI). In line with the irregular gonadal hormone level and estrus cycles, subfertility of female mice was also confirmed by analyzing numbers of litters and pups. The in vitro study suggested that granulosa cells could uptake MC-LR and should be the target of the toxicant. Oxidative stress in granulose cells induced by MC-LR promoted follicle atresia and eventually leads to female subfertility.
Project description:The thyroid hormones act on nearly every cell in the body. Moreover, the thyroid gland continuously interacts with the ovaries, and the thyroid hormones are involved in almost all phases of reproduction. Thyroid dysfunctions are relatively common among women of reproductive age, and can affect fertility in various ways, resulting in anovulatory cycles, high prolactin levels, and sex hormone imbalances. Undiagnosed and untreated thyroid disease can be a cause of subfertility. Subclinical hypothyroidism (SCH), also known as mild thyroid failure, is diagnosed when peripheral thyroid hormone levels are within the normal reference laboratory range, but serum thyroid-stimulating hormone levels are mildly elevated. Thyroid autoimmunity (TAI) is characterized by the presence of anti-thyroid antibodies, which include anti-thyroperoxidase and anti-thyroglobulin antibodies. SCH and TAI may remain latent, asymptomatic, or even undiagnosed for an extended period. It has also been demonstrated that controlled ovarian hyperstimulation has a significant impact on thyroid function, particularly in women with TAI. In the current review, we describe the interactions between thyroid dysfunctions and subfertility, as well as the proper work-up and management of thyroid dysfunctions in subfertile women.
Project description:Progesterone (P4) is essential for female fertility. The objective of this study was to evaluate the functional requirement of the nonclassical P4 receptor (PGR), PGR membrane component 1, in regulating female fertility. To achieve this goal, the Pgrmc1 gene was floxed by insertion of loxP sites on each side of exon 2. Pgrmc1 floxed (Pgrmc1(fl/fl)) mice were crossed with Pgr(cre) or Amhr2(cre) mice to delete Pgrmc1 (Pgrmc1(d/d)) from the female reproductive tract. A 6-month breeding trial revealed that conditional ablation of Pgrmc1 with Pgr(cre/+) mice resulted in a 40% reduction (P = .0002) in the number of pups/litter. Neither the capacity to ovulate in response to gonadotropin treatment nor the expression of PGR and the estrogen receptor was altered in the uteri of Pgrmc1(d/d) mice compared with Pgrmc1(fl/fl) control mice. Although conditional ablation of Pgrmc1 from mesenchymal tissue using Amhr2(cre/+) mice did not reduce the number of pups/litter, the total number of litters born in the 6-month breeding trial was significantly decreased (P = .041). In addition to subfertility, conditional ablation of Pgrmc1 using either Amhr2(cre/+) or Pgr(cre/+) mice resulted in the development of endometrial cysts starting around 4 months of age. Interestingly, pregnancy attenuated the formation of these uterine cysts. These new findings demonstrate that PGR membrane component 1 plays an important role in female fertility and uterine tissue homeostasis.
Project description:Mothers can influence prenatal conditions by varying the amount of nutrients, hormones or antioxidants they provide to their developing young. Some of these substances even affect the transfer of these compounds in the next generation, but it is less clear how different maternally transmitted compounds interact with each other to shape reproductive resource allocation in their offspring. Here, we found that female Japanese quails (Coturnix japonica) that were exposed to high carotenoid levels during embryonic development transferred lower concentrations of yolk antioxidants to their own eggs later in life. This effect disappeared when both testosterone and carotenoid concentrations were manipulated simultaneously, showing long-term and interactive effects of these maternally derived egg components on a female's own egg composition. Given that exposure to high levels of testosterone during embryo development stimulates the production of reactive oxygen species (ROS) and impairs antioxidant defenses, we propose that carotenoids act as in ovo antioxidants in an oxidatively stressful environment (i.e. when levels of testosterone are high) but might have prooxidant properties in an environment where they are not used to counteract an increased production of ROS. In line with this hypothesis, we previously showed that prenatal exposure to increased concentrations of yolk carotenoids leads to a rise of oxidative damage at adulthood, but only when yolk testosterone concentrations were not experimentally increased as well. As a consequence, antioxidants in the body may be used to limit oxidative damage in females exposed to high levels of carotenoids during development (but not in females exposed to increased levels of both carotenoids and testosterone), resulting in lower amounts of antioxidants being available for deposition into eggs. Since prenatal antioxidant exposure is known to influence fitness-related traits, the effect detected in this study might have transgenerational consequences.
Project description:Antioxidants are widely used to protect cells from damage induced by reactive oxygen species (ROS). The concept that antioxidants can help fight cancer is deeply rooted in the general population, promoted by the food supplement industry, and supported by some scientific studies. However, clinical trials have reported inconsistent results. Here, we show that supplementing the diet with the antioxidants N-acetylcysteine (NAC) and vitamin E markedly increases tumor progression and reduces survival in mouse models of B-RAF- and K-RAS-induced lung cancer. RNA sequencing revealed that NAC and vitamin E, which are structurally unrelated, produce highly coordinated changes in tumor transcriptome profiles, dominated by reduced expression of endogenous antioxidant genes. NAC and vitamin E increase tumor cell proliferation by reducing ROS, DNA damage, and p53 expression in mouse and human lung tumor cells. Inactivation of p53 increases tumor growth to a similar degree as antioxidants and abolishes the antioxidant effect. Thus, antioxidants accelerate tumor growth by inactivating the ROS-p53 axis. Because p53 inactivation occurs late in tumor progression, antioxidants may accelerate the growth of early tumors or precancerous lesions in high-risk populations such as smokers and patients with chronic obstructive pulmonary disease who receive NAC to relieve mucus production.