Leptin and mitogen-activated protein kinase (MAPK) in oocytes of sows and gilts

Follicular fluid exosome-derived miR-339-5p enhances in vitro maturation of porcine oocytes via targeting SFPQ, a regulator of the ERK1/2 pathway

In this study, we aimed to investigate cytoplasmic maturation and miRNA expression of mature oocytes cultured in porcine follicular fluid exosomes. We also examined the effect of miR-339-5p on oocyte maturation. Twenty eight differentially expressed miRNAs were detected using miRNA-seq. We then transfected cumulus oocyte complexes with miR-339-5p mimics and inhibitor during culture. The results showed that exosomes increased endoplasmic reticulum levels and the amount of lipid droplets, and decreased ROS levels, lipid droplet size, and percentage of oocytes with abnormal cortical granule distribution. Overexpressing miR-339-5p significantly decreased cumulus expansion genes, oocyte maturation-related genes, target gene proline/glutamine-rich splicing factor (SFPQ), ERK1/2 phosphorylation levels, oocyte maturation rate, blastocyst rate, and lipid droplet number, but increased lipid droplet size and the ratio of oocytes with abnormal cortical granule distribution. Inhibiting miR-339-5p reversed the decrease observed during overexpression. Mitochondrial membrane potential and ROS levels did not differ significantly between groups. In summary, exosomes promote oocyte cytoplasmic maturation and miR-339-5p regulating ERK1/2 activity through SFPQ expression, thereby elevating oocyte maturation and blastocyst formation rate in vitro.

Lab partners: oocytes, embryos and company. A personal view on aspects of oocyte maturation and the development of monozygotic twins

The present review addresses the oocyte and the preimplantation embryo, and is intended to highlight the underlying principle of the "nature versus/and nurture" question. Given the diversity in mammalian oocyte maturation, this review will not be comprehensive but instead will focus on the porcine oocyte. Historically, oogenesis was seen as the development of a passive cell nursed and determined by its somatic compartment. Currently, the advanced analysis of the cross-talk between the maternal environment and the oocyte shows a more balanced relationship: Granulosa cells nurse the oocyte, whereas the latter secretes diffusible factors that regulate proliferation and differentiation of the granulosa cells. Signal molecules of the granulosa cells either prevent the precocious initiation of meiotic maturation or enable oocyte maturation following hormonal stimulation. A similar question emerges in research on monozygotic twins or multiples: In Greek and medieval times, twins were not seen as the result of the common course of nature but were classified as faults. This seems still valid today for the rare and until now mainly unknown genesis of facultative monozygotic twins in mammals. Monozygotic twins are unique subjects for studies of the conceptus-maternal dialogue, the intra-pair similarity and dissimilarity, and the elucidation of the interplay between nature and nurture. In the course of in vivo collections of preimplantation sheep embryos and experiments on embryo splitting and other microsurgical interventions we recorded observations on double blastocysts within a single zona pellucida, double inner cell masses in zona-enclosed blastocysts and double germinal discs in elongating embryos. On the basis of these observations we add some pieces to the puzzle of the post-zygotic genesis of monozygotic twins and on maternal influences on the developing conceptus.

Contribution of key elements of nutritional metabolism to the development of cystic ovarian disease in dairy cattle

The alteration of signaling molecules involved in the general metabolism of animals can negatively influence reproduction. In dairy cattle, the development of follicular cysts and the subsequent appearance of ovarian cystic disease (COD) often lead to decreased reproductive efficiency in the herd. The objective of this review is to summarize the contribution of relevant metabolic and nutritional sensors to the development of COD in dairy cows. In particular, we focus on the study of alterations of the insulin signaling pathway, adiponectin, and other sensors and metabolites relevant to ovarian functionality, which may be related to the development of follicular persistence and follicular formation of cysts in dairy cattle. The results of these studies support the hypothesis that systemic factors could alter the local scenario in the follicle, generating an adverse microenvironment for the resumption of ovarian activity and possibly leading to the persistence of follicles and to the development and recurrence of COD.

Probiotic supplementation affects IGF-1 and leptin levels in Nile tilapia hepatopancreatic tissue

ABSTRACT This work aimed to assess the effect of the probiotic strain, Lactobacillus plantarum, on the levels of leptin, IGF-1 and their receptors on the hepatopancreatic tissues of Nile tilapia (Oreochromis niloticus) and then correlate fish growth performance and gut microbiological parameters. Fish juveniles (±23g) were reared in a recirculation system with constant aeration and temperature (25°C). They were distributed into six polyethylene tanks (45L) and fed twice a day at 5% of the tank biomass with the respective diets: control (commercial diet without probiotic) and supplemented with L. plantarum inoculum (1 x 108 CFU mL-1), both in triplicate. After 30 days of feeding, L. plantarum-fed fishes showed greater weekly growth rate, final weight, and feed conversion rate, in addition to higher count of lactic-acid bacteria and lower count of pathogenic bacteria in the intestinal tract, when compared to the control group. The immunostaining intensity for IGF-1 and leptin hormones was lower after L. plantarum supplementation than in the control group, with no change in the level for receptors. This reduction could implicate important changes in fish metabolism and homeostasis.

Regulation and function of leptin during ovarian follicular development in cows

Although it is well documented that leptin signals the body nutritional status to the brain, mechanisms of leptin regulation at the ovary are not well understood. This study was conducted to determine whether there was leptin and the receptor for leptin (LEPR) in cattle ovarian follicles and to investigate potential actions of leptin on follicular growth in vivo and on regulation of granulosa cell functions in vitro. There was leptin and LEPR in granulosa and theca cells of dominant and subordinate follicles, with greater immunostaining for leptin in granulosa cells of subordinate follicles. There was a lesser relative abundance of leptin receptor gene-related protein (LEPROT) and of the adiponectin receptors 1 (ADIPOR1) and 2 (ADIPOR2) mRNA transcripts in granulosa cells of subordinate than dominant follicles (P < 0.05). Intrafollicular injection of either 100 or 1000 ng/mL leptin did not affect the diameter and the growth of dominant follicles (P> 0.05). Supplementation of in vitro culture medium with different leptin concentations did not affect (P > 0.05) the relative abundance of hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1 (HSD3B1), cytochrome P450 family 11 subfamily A member 1 (CYP11A1), signal transducer and activator of transcription 3 (STAT3) and X-linked inhibitor of apoptosis protein (XIAP) mRNA transcripts in granulosa cells. These findings indicate that leptin and LEPR are present in the follicular cells of cattle ovaries, but leptin apparently does not have essential functions in steroidogenesis and growth of dominant follicles.

Variations in the Expression Pattern of HSP27 and MSK1 Genes During the Development of Prehierarchical Follicles in the Zi Geese (Anser Cygnoides)

The p38MAPKs (mitogen-activated protein kinases) signaling contributes a pivotal role in mammalian ovarian follicular development; however, the knowledge regarding their expression in geese remains unresolved. The objective of the current study was to determine the spatio-temporal expression of heat shock protein 27 (HSP27) and mitogen- and stress-activated protein kinase 1 (MSK1) genes in the prehierarchical follicles during geese ovarian development. The prehierarchical follicles samples were harvested from 35- to 37-week-old healthy laying geese. HSP27 and MSK1 relative expression in various sized prehierachical follicles was detected by real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting. Follicular wall localization of HSP27 and MSK1 was examined by using immunohistochemistry. Our results at mRNA level indicated that HSP27 was highly expressed in middle white follicles whereas MSK1 was predominantly expressed in small white follicles. The western blotting results for HSP27 and MSK1 were inconsistent with the RT-qPCR results in various stages of prehierachical follicular development but noticeably, HSP27 proteins were still expressed more in middle white follicles while MSK1 proteins were more abundant in primary follicles. At different stages of prehierarchical development, immunodetections in the granulosa and theca cells revealed that HSP27 was intensively localized in middle white follicles while strong detections of MSK1 were observed in large white follicles. These results indicate HSP27 and MSK1 might be associated to the key regulators of folliculogenesis in geese.

Effects of supplying omega-3 polyunsaturated fatty acids to gilts after weaning on metabolism and ovarian gene expression

Omega-3 PUFA may benefit sow reproductive performance, but effects on weaned gilts are unknown. This study evaluated the effects of supplementing omega-3 PUFA to gilts after weaning on growth, metabolic markers, and gene expression of steroidogenic enzymes and hormone receptors. For 52 d, gilts in the control group were fed 100 g/d of regular diets, whereas gilts in the omega-3 group were fed 75 g/d of such diets plus 25 g/d of the microalgae Schizochytium sp. (3.5 g/d of omega-3 PUFA; n = 8 gilts/group). Blood samples were collected at day 0, day 21, and day 52. Total serum cholesterol levels were lower for the omega-3 group than for the control group (P < 0.05), but high-density lipoprotein-cholesterol levels were reduced at day 52 for both groups (P < 0.05). Gilts in the omega-3 group presented lower feed intake, better feed conversion, and less-intense immunolabeling for leptin and its receptor in the cytoplasm of oocytes included in primordial/primary follicles than gilts in the control group (P < 0.05). The expression of genes coding for cholesterol side-chain cleavage and aromatase enzymes and the LH receptor in follicular cells was lower for supplemented gilts (P < 0.05). Compared with controls, supplemented gilts presented decreased serum cholesterol levels and better feed conversion, but leptin presence and gene expression for steroidogenic enzymes and for the LH receptor were lower at ovarian level.

Lipidomic Components Alterations of Human Follicular Fluid Reveal the Relevance of Improving Clinical Outcomes in Women Using Progestin-Primed Ovarian Stimulation Compared to Short-Term Protocol

BACKGROUND Increasing the success rate of in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) is a duty of clinicians that has made many seek a variety of protocols. This study was undertaken to use a liquid chromatography-mass spectrometry (LC-MS) to define the alterations of follicular fluid (FF) lipid metabolites in patients undergoing progestin-primed ovarian stimulation (PPOS) compared with short-term protocol, revealing potential correlations between the differentially expressed lipids and ameliorative clinical outcomes. MATERIAL AND METHODS Ninety-three infertile women undergoing IVF/ICSI treatment with PPOS (n=62) or a short-term protocol (n=31) were prospectively enrolled in a randomized controlled trial. FF samples were obtained from dominant follicles at the time of oocyte retrieval. Lipid metabolism profiles were analyzed using LC-MS. RESULTS Twelve lipids were found to be higher in patients treated with the PPOS protocol than in those receiving the short-term protocol, including triacylglycerols (TAG-34: 1+NH4, TAG-58: 0+NH4, TAG-64: 3+NH4, and TAG-64: 8+NH4), diacylglycerol DAG-38: 6+NH4, phosphatidylglycerols (PG-26: 0, PG-30: 2, and PG-40: 5), phosphatidylethanolamine PE-32: 2, lysophosphatidylethanolamine LPE-14: 1, lysophosphatidylinositol LPI-12: 0, and lysophosphatidylcholine LPC-16: 0. CONCLUSIONS Our data demonstrate that the PPOS protocol increases the levels of 12 lipids in FF, which reveals a strong association between the differentially elevated lipids and better IVF/ICSI outcomes.

Ovarian aging and the activation of the primordial follicle reserve in the long-lived Ames dwarf and the short-lived bGH transgenic mice

The aim of this study was to evaluate the effect of growth hormone (GH) in the maintenance of the ovarian primordial follicle reserve. Ovaries from 16 mo old GH-deficient Ames Dwarf (df/df) and Normal (N/df) mice were used. A subgroup of df/df and N mice received GH or saline injections for six weeks starting at 14 mo of age. In addition, ovaries from 12 mo old mice overexpressing bovine GH (bGH) and controls were used. df/df mice had higher number of primordial and total follicles than N/df mice (p < 0.05), while GH treatment decreased follicle counts in both genotypes (p < 0.05). In addition, bGH mice had lower number of primordial and total follicles than the controls (p < 0.05). pFoxO3a levels were higher in mice treated with GH and in bGH mice (p < 0.05) when comparing with age match controls. These results indicate that increased circulating GH is associated with a reduced ovarian primordial follicle reserve and increased pFoxO3a content in oocytes.

Expression patterns of p38αMAPK during follicular development in the ovaries of neonatal rats

The p38αMAPK signaling pathway plays a critical role in female reproduction, but an understanding of its expression in rats remains elusive. This study was carried out to investigate the temporal and spatial expression of p38αMAPK and p-p38αMAPK. Ovarian tissue samples were collected from 2-, 4-, 8-, 12-, 16-, 20- and 30-day-old female rats. Western blotting was used to examine the relative expression of p38αMAPK and p-p38αMAPK in ovarian tissue, and subcellular localization was examined using immunohistochemistry of the rat ovaries at different ages of postpartum. The immunohistochemical results showed that p38αMAPK and p-p38αMAPK were widely expressed in the rat ovaries, mainly localized in the follicle cells and granulosa cells. The expression of p38αMAPK was relatively stable for the different stages of oocytes, whereas the expression of p-p38αMAPK gradually increased. At different stages of granulosa cells, the expression of p38αMAPK was also relatively stable, and the p-p38αMAPK expression showed an upward trend during follicular development. Western blotting revealed that the expression of p38αMAPK in the ovaries was relatively stable, where as p-p38αMAPK expression initially exhibited an increasing trend and subsequently decreased, with a maximum at day 20. The expression patterns of p38αMAPK and p-p38αMAPK in the rat ovaries indicate their possible involvement in folliculogenesis. Taken together, the stage- and cell-specific expression of p-p38αMAPK in rat ovaries indicated that p-p38αMAPK might play a vital role during rat follicular development.

Effect of spineless cactus intake (Opuntia ficus-indica) on blood glucose levels in lactating sows and its impact on feed intake, body weight loss, and weaning-estrus interval

The effect of spineless cactus intake (Opuntia ficus-indica) on blood glucose (BG) levels in lactating sows and its impact on daily and total feed intake (dFI⁻¹ and TFI, respectively), body weight loss (BWL), and weaning-estrus interval length (WEI) were evaluated. Thirty-four hybrid (Yorkshire × Landrace × Pietrain) sows in lactation phase were used. Sows were divided into two groups: G1 (n = 17) where they received commercial feed and G2 (n = 17) provided with commercial feed plus an average of 2.0 ± 0.5 kg spineless cactus, based on a sow’s body weight. The variables evaluated were BG, dFI⁻¹, TFI, BWL, and WEI. Statistical analysis was performed by using a fixed and mixed model methodology, under a repeated measurements experiment. Group effects were found on all analyzed variables (P < 0.05). The BG was lower in G2 (55.2 and 64.5 mg/dL pre- and post-prandial, respectively), compared to that in G1 (70.9 and 80.1 mg/dL pre- and post-prandial, respectively) (P < 0.05). G2 showed better performance than G1 for dFI⁻¹, BWL, and WEI (P < 0.05) whose averages were 5.5 ± 1.8 kg, 7.4 ± 4.5%, and 5.3 ± 1.2 days, respectively. Averages for these variables in G1 were 4.7 ± 1.5 kg, 16.8 ± 4.6%, and 6.1 ± 1.6 days, respectively. Intake of spineless cactus reduced BG levels in lactating sows, generating greater dFI⁻¹, lower BWL at the end of lactation, and a lower WEI.

An essential role for the intra-oocyte MAPK activity in the NSN-to-SN transition of germinal vesicle chromatin configuration in porcine oocytes

The mechanisms for the transition from non-surrounded nucleolus (NSN) to surrounded nucleolus (SN) chromatin configuration during oocyte growth/maturation are unclear. By manipulating enzyme activities and measuring important molecules using small-follicle pig oocytes with a high proportion of NSN configuration and an extended germinal vesicle stage in vitro, this study has the first time up-to-date established the essential role for intra-oocyte mitogen-activated protein kinase (MAPK) in the NSN-to-SN transition. Within the oocyte in 1–2 mm follicles, a cAMP decline activates MAPK, which prevents the NSN-to-SN transition by activating nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) while inhibiting histone deacetylase (HDAC). In cumulus cells of 1–2 mm follicles, a lower level of estradiol and oocyte-derived paracrine factor (ODPF) reduces natriuretic peptide receptor 2 (NPR2) while enhancing FSH and cAMP actions. FSH elevates cAMP levels, which decreases NPR2 while activating MAPK. MAPK closes the gap junctions, which, together with the NPR2 decrease, reduces cyclic guanosine monophosphate (cGMP) delivery leading to the cAMP decline within oocytes. In 3–6 mm follicles, a higher level of estradiol and ODPF and a FSH shortage initiate a reversion of the above events leading to MAPK inactivation and NSN-to-SN transition within oocytes.

Primordial follicle activation in the ovary of Ames dwarf mice

Background

The insulin receptor substrate 1 (IRS1), phosphoinositide 3-kinase (Pi3k), protein kinase B (Akt1), Forkhead Box O3a (FOXO3a) pathway is directly involved in aging and ovarian activation of follicle growth. Therefore, the aim of this work was to measure the expression of genes related to the ovarian pathway for activation of primordial follicles and FOXO3a protein phosphorylation between young and old female Ames dwarf (df/df) and normal (N) mice.

Methods

For this study ovaries from N (n = 10) and df/df (n = 10) female mice were collected at 5–6 months of age and at 21–22 months of age. For immunohistochemistry ovaries from 12 month-old and df/df mice were used.

Results

The expression of Irs1, Pi3k, Akt1, mammalian target of rapamycin (Mtor), suppressor of cytokine signaling −2 (Socs2), Socs3 was lower (P < 0.05) in older than younger N mice and not different (P > 0.05) between young and old df/df mice. The expression of Foxo3a was also lower (P < 0.05) in old than younger N and df/df mice and was higher (P < 0.05) in old df/df than N mice. Expression of Amh was lower (P < 0.05) in old than young N and df/df mice and was higher (P = 0.0009) in df/df than N mice. Imunnostaining for p-FOXO3 was lower in df/df than N mice (P < 0.001), although FOXO3 immunostaining was not different (P > 0.05) between df/df and N mice.

Conclusions

In sum, the present study indicates that lower expression of Irs1, Socs2, Socs3, Akt1, Pi3k, Mtor and Foxo3a mRNA in the ovaries of older mice of both genotypes is associated to a reduced ovarian activity revealed by lower expression of Amh mRNA. At the same time, ovaries of old df/df mice maintained higher expression of Foxo3a mRNA, which was associated to higher ovarian activity. We have shown that df/df females have a lower level of p-FOXO3 in oocytes from primordial/primary follicles, an important activator of follicular growth. Therefore, this study strongly indicates that Prop1^df mutation causes delayed ovarian aging.