Comparative analysis of PI3K-AKT and MEK-ERK1/2 signaling-driven molecular changes in granulosa cells.

In Brief: PI3K-AKT signaling activates steroidogenesis by inducing estradiol and progesterone production, while MEK-ERK1/2 signaling regulates steroidogenesis by inhibiting estradiol and inducing progesterone production in granulosa cells (GCs). Both pathways are essential for glycolytic and mitochondrial metabolism in these cells.

Abstract: The PI3K-AKT and MEK-ERK1/2 signaling pathways are integral to fundamental cellular processes, such as proliferation, viability and differentiation.

Saturated fatty acids inhibit unsaturated fatty acid induced glucose uptake involving GLUT10 and aerobic glycolysis in bovine granulosa cells.

Fatty acids have been shown to modulate glucose metabolism in vitro and in vivo. However, there is still a need for substantial evidence and mechanistic understanding in many cell types whether both saturated and unsaturated fatty acids (SFAs and UFAs) pose a similar effect and, if not, what determines the net effect of fatty acid mixes on glucose metabolism. In the present study, we asked these questions by treating granulosa cells (GCs) with the most abundant non-esterified fatty acid species in bovine follicular fluid.

ERK1/2-SOX9/FOXL2 axis regulates ovarian steroidogenesis and favors the follicular-luteal transition.

Estradiol and progesterone are the primary sex steroids produced by the ovary. Upon luteinizing hormone surge, estradiol-producing granulosa cells convert into progesterone-producing cells and eventually become large luteal cells of the corpus luteum. Signaling pathways and transcription factors involved in the cessation of estradiol and simultaneous stimulation of progesterone production in granulosa cells are not clearly understood.

The Imitation of the Ovarian Fatty Acid Profile of Superfertile Dummerstorf Mouse Lines during IVM of Control Line Oocytes Could Influence Their Maturation Rates.

Declining human fertility worldwide is an attractive research target for the search for "high fertility" genes and pathways to counteract this problem. To study these genes and pathways for high fertility, the superfertile Dummerstorf mouse lines FL1 and FL2 are two unique model organisms representing an improved fertility phenotype. A direct reason for this remarkable characteristic of increased litter size, which reaches >20 pups/litter in both FLs, is the raised ovulation rate by approximately 100%, representing an impressive record in this field.

Alterations in gonadotropin, apoptotic and metabolic pathways in granulosa cells warrant superior fertility of the Dummerstorf high fertility mouse line 1.

The development and maturation of ovarian follicles is a complex and highly regulated process, which is essential for successful ovulation. During recent decades, several mouse models provided insights into the regulation of folliculogenesis. In contrast to the commonly used transgenic or knockout mouse models, the Dummerstorf high-fertility mouse line 1 (FL1) is a worldwide unique selection experiment for increased female reproductive performance and extraordinary high fertility.

Lower Plasmatic Levels of Saturated Fatty Acids and a Characteristic Fatty Acid Composition in the Ovary Could Contribute to the High-Fertility Phenotype in Dummerstorf Superfertile Mice.

In recent decades, fertility traits in humans as well as in farm animals have decreased worldwide. As such, it is imperative to know more about the genetics and physiology of increased or high fertility. However, most of the current animal models with reproductive phenotypes describe lower fertility or even infertility (around 99%).

Estradiol production of granulosa cells is unaffected by the physiological mix of nonesterified fatty acids in follicular fluid.

Ovarian cycle is controlled by circulating levels of the steroid hormone 17-β-estradiol, which is predominantly synthesized by the granulosa cells (GCs) of ovarian follicles. Our earlier studies showed that unsaturated fatty acids (USFs) downregulate and saturated fatty acids (SFAs) upregulate estradiol production in GCs. However, it was unclear whether pituitary gonadotropins induce accumulation of free fatty acids (FFAs) in the follicular fluid since follicle-stimulating hormone induces and luteinizing hormone inhibits estradiol production in the mammalian ovary.

Higher quality rather than superior quantity of oocytes determine the amount of fertilizable oocytes in two outbred Dummerstorf high-fertility mouse lines.

Dummerstorf fertility lines FL1 and FL2 represent two models of enhanced fertility characterized by the doubling of the litter size compared with an unselected control population (ctrl line, Dummerstorf FztDU). Both biodiverse FLs managed to reach this goal by increasing the ovulation rate per cycle, even showing decreased pregnancy rate and irregular oestrous cycle and metabolic hormone levels, compared with ctrl. The aim of the present study was to analyse oocytes in terms of quality and quantity by comparing the entire pool of oocytes per ovary, with those from the antral follicles within the same animal.

Endocrine and molecular factors of increased female reproductive performance in the Dummerstorf high-fertility mouse line FL1.

The Dummerstorf high-fertility mouse line FL1 is a worldwide unique selection experiment for increased female reproductive performance. After more than 190 generations of selection, these mice doubled the amount of offspring per litter compared to the unselected control line. FL1 females have a superior lifetime fecundity and the highest Silver fecundity index that has been described in mice, while their offspring show no signs of growth retardation.

Altered insulin, leptin and ghrelin hormone levels and atypical estrous cycle lengths in two highly fertile mouse lines.

Mouse models of decreased fertility mainly support scientific knowledge in the field of reproductive biology. In this study, we changed the perspective, using Dummerstorf high-fertility mouse lines FL1 and FL2 selected for increased reproductive performances that doubled the amount of ovulated oocytes per cycle and the number of offspring per litter compared to an unselected control line (founder population, FZTDU, ctrl). After recent observations, both fertility lines seem to show a lower pregnancy rate compared to ctrl together with an atypical reproductive cycle.

Two mouse lines selected for large litter size display different lifetime fecundities.

We recently described two outbred mouse lines that were selected for large litter size at first delivery. However, lifetime fecundity appears to be economically more important for the husbandry of many polytocous species for which mouse lines might serve as bona fide animal models (e.g.

Altered testicular cell type composition in males of two outbred mouse lines selected for high fertility.

Background: Recently we described two outbred mouse lines which have been selected for high fertility. These mouse models doubled the number of offspring per litter.

Objectives: Although selected for a primarily female-trait of high fertility (increased litter size), we were interested whether also males of the fertility lines show differences within their reproductive organs.

HIF1 driven transcriptional activity regulates steroidogenesis and proliferation of bovine granulosa cells.

Hypoxia-inducible factor 1 (HIF1) is a heterodimeric transcription factor, consisting of a constitutively expressed β-subunit (HIF1B) and a regulated α-subunit (HIF1A). In the present study, we analyzed the HIF1 driven transcriptional activity in bovine granulosa cells (GC). Treatment of GC with FSH (follicle stimulating hormone) and IGF1 (insulin-like growth factor 1) resulted in the upregulation of HIF1A mRNA expression under normoxia.

Testicular transcriptional signatures associated with high fertility.

Factors of high fertility are poorly described. The majority of transgenic or knockout models with a reproductive phenotype are subfertile or infertile phenotypes. Few genotypes have been linked to improved reproductive performance (0.

Selection for female traits of high fertility affects male reproductive performance and alters the testicular transcriptional profile.

Background: Many genes important for reproductive performance are shared by both sexes. However, fecundity indices are primarily based on female parameters such as litter size. We examined a fertility mouse line (FL2), which has a considerably increased number of offspring and a total litter weight of 180% compared to a randomly bred control line (Ctrl) after more than 170 generations of breeding.

Reproductive performance primarily depends on the female genotype in a two-factorial breeding experiment using high-fertility mouse lines.

Mouse models showing an improved fertility phenotype are barely described in the literature. In the present study, we further characterized two outbred mouse models that have been selected for the phenotype 'high fertility' for more than 177 generations (fertility lines (FL) 1 and 2). In order to delineate the impact of males and females on fertility parameters, we performed a two-factorial breeding experiment by mating males and females of the three different genotypes (FL1, FL2, unselected control (Ctrl)) in all 9 possible combinations.

In vivo microinjection and electroporation of mouse testis.

This video and article contribution gives a comprehensive description of microinjection and electroporation of mouse testis in vivo. This particular transfection technique for testicular mouse cells allows the study of unique processes in spermatogenesis. The following protocol focuses on transfection of testicular mouse cells with plasmid constructs.

Selenoprotein P in seminal fluid is a novel biomarker of sperm quality.

Hepatically-derived selenoprotein P (SePP) transports selenium (Se) via blood to other tissues including the testes. Male Sepp-knockout mice are infertile. SePP-mediated Se transport to Sertoli cells is needed for supporting biosynthesis of the selenoenzyme glutathione peroxidase-4 (GPX4) in spermatozoa.

High-fertility phenotypes: two outbred mouse models exhibit substantially different molecular and physiological strategies warranting improved fertility.

Animal models are valuable tools in fertility research. Worldwide, there are more than 400 transgenic or knockout mouse models available showing a reproductive phenotype; almost all of them exhibit an infertile or at least subfertile phenotype. By contrast, animal models revealing an improved fertility phenotype are barely described.

Selenium-dependent pre- and posttranscriptional mechanisms are responsible for sexual dimorphic expression of selenoproteins in murine tissues.

Important enzymes for thyroid hormone metabolism, antioxidative defense, and intracellular redox control contain selenocysteine (Sec) in their active centers. Expression of these selenoproteins is tightly controlled, and a sex-specific phenotype is observed on disturbance of selenium (Se) transport in mice. Therefore, we analyzed Se concentrations and expression levels of several selenoproteins including type I iodothyronine deiodinase (Dio1) and glutathione peroxidase (GPx) isozymes in male and female mice.

Synthesis and metabolism of thyroid hormones is preferentially maintained in selenium-deficient transgenic mice.

The thyroid gland is rich in selenium (Se) and expresses a variety of selenoproteins that are involved in antioxidative defense and metabolism of thyroid hormones (TH). Se deficiency impairs regular synthesis of selenoproteins and adequate TH metabolism. We recently generated mice that lack the plasma Se carrier, selenoprotein P (SePP).

Hepatic deiodinase activity is dispensable for the maintenance of normal circulating thyroid hormone levels in mice.

Thyroid hormone (TH) homeostasis depends on peripheral activation and inactivation of iodothyronines by selenoenzymes of the deiodinase (Dio) family. We genetically inactivated hepatic selenoenzyme expression, including Dio1, in order to determine the contribution of hepatic Dio to circulating TH levels. Serum levels of TSH, total T(4), and total T(3) were not different from controls.

Efficient selenium transfer from mother to offspring in selenoprotein-P-deficient mice enables dose-dependent rescue of phenotypes associated with selenium deficiency.

Mice deficient in selenoprotein P exhibit a disturbed selenium distribution and reduced activities of other selenoenzymes and display defects in growth and motor co-ordination. We have normalized selenoenzyme activities and rescued the phenotype of mutant mice by supplementing their nursing mothers with sodium selenite. Our results indicate that selenium from inorganic sources can be transferred efficiently via mother's milk to the developing offspring in a form that is both highly bioavailable by target tissues and yet sufficiently safe to prevent overdosages.

Interstitial magnetic resonance lymphography using a polymeric t1 contrast agent: initial experience with Gadomer-17.

Rationale And Objectives: The detection of lymph node metastases is an important step in tumor staging and is significant for therapy planning. Lymph node-specific contrast agents can raise the sensitivity and specificity of modern diagnostic methods. This study investigated the suitability of the dendritic contrast agent Gadomer-17 in magnetic resonance (MR) lymph node imaging and compared three different dosages in such an application.