A potential role of knockout serum replacement as a porcine follicular fluid substitute for in vitro maturation: Lipid metabolism approach

Effect assessment of a type of xeno-free and serum-free human adipose-derived mesenchymal stem cells culture medium by proliferation and differentiation capacities

Human mesenchymal stem cells (hMSCs) possess broad prospects in pre-clinical research. In vitro amplification of hMSCs requires appropriate medium to reach the number of seed cells with clinical significance. However, the uncertainty of the heterologous components of the traditional fetal bovine serum (FBS) culture medium has great safety risks. Moreover, existing commercial hMSCs medium is very expensive, therefore a safer and more optimal hMSCs medium is urgently needed. Accordingly, we developed five components adipose-derived hMSCs (hADMSCs) medium without xenogenic components, named E5 SFM. which is mainly composed of knockout serum replacement (KSR), and additionally four components such as fibroblast growth factor and transferrin. Here, we mainly compared the E5 SFM with traditional FBS-containing medium and a commercial medium by surface markers testing, proliferation assay as well as osteogenic, adipogenic and chondrogenic differentiation assessment. We demonstrated that hADMSCs cultured in the E5 SFM showed similar morphological characteristics and immunophenotypes to those in other media. Notably, cell proliferative capability was similar to that in the commercial medium, but higher than that in the FBS-containing medium and other media. Additionally, their capabilities of adipogenic and osteogenic differentiation were significantly higher than those of other media. Consequently, we concluded that the E5 SFM medium can not only effectively promote cell proliferation of hMSCs, but also has optimal differentiative capacity and clear and simple ingredients.

Porcine Follicular Fluid-Derived Exosome: The Pivotal Material for Porcine Oocyte Maturation in Lipid Antioxidant Activity

Several studies have examined exosomes derived from porcine follicular fluid (FF), but few have reported their application in controlled experiments. The main concern in the field of embryology may be that controlled conditions, such as using a defined medium intermittently, cause poor results in mammalian oocyte maturation and embryo development. The first reason is the absence of the FF, which copes with the majority of the processes emerging in oocytes and embryos. Therefore, we added exosomes derived from porcine FF to the maturation medium of porcine oocytes. For morphological assessment, cumulus cell expansion and subsequent embryonic development were evaluated. Moreover, several stainings, such as glutathione (GSH) and reactive oxygen species (ROS), fatty acid, ATP, and mitochondrial activity, as well as evaluations of gene expression and protein analysis, were used for the functional verification of exosomes. When the oocytes were treated with exosomes, the lipid metabolism and cell survival of the oocytes were fully recovered, as well as morphological evaluations compared to the porcine FF-excluded defined medium. Therefore, controlled experiments may produce reliable data if the exosomes are treated with the desired amounts, and we suggest applying FF-derived exosomes to promote experimental data when performing controlled experiments in embryology.

Medium supplementation can influence the human ovarian cells in vitro

BACKGROUND

Cells are an essential part of the triple principles of tissue engineering and a crucial component of the engineered ovary as they can induce angiogenesis, synthesize extracellular matrix and influence follicle development. Here, we hypothesize that by changing the medium supplementation, we can obtain different cell populations isolated from the human ovary to use in the engineered ovary. To this end, we have in vitro cultured cells isolated from the menopausal ovarian cortex using different additives: KnockOut serum replacement (KO), fetal bovine serum (FBS), human serum albumin (HSA), and platelet lysate (PL).

RESULTS

Our results showed that most cells soon after isolation (pre-culture, control) and cells in KO and FBS groups were CD31- CD34- (D0: vs. CD31-CD34+, CD31 + CD34+, and CD31 + CD34- p < 0.0001; KO: vs. CD31-CD34+, CD31 + CD34+, and CD31 + CD34- p < 0.0001; FBS: vs. CD31-CD34+ and CD31 + CD34+ p < 0.001, and vs. CD31 + CD34- p < 0.01). Moreover, a deeper analysis of the CD31-CD34- population demonstrated a significant augmentation (more than 86%) of the CD73+ and CD90+ cells (possibly fibroblasts, mesenchymal stem cells, or pericytes) in KO- and FBS-based media compared to the control (around 16%; p < 0.001). Still, in the CD31-CD34- population, we found a higher proportion (60%) of CD90+ and PDPN+ cells (fibroblast-like cells) compared to the control (around 7%; vs PL and KO p < 0.01 and vs FBS p < 0.001). Additionally, around 70% of cells in KO- and FBS-based media were positive for CD105 and CD146, which may indicate an increase in the number of pericytes in these media compared to a low percentage (4%) in the control group (vs KO and FBS p < 0.001). On the other hand, we remarked a significant decrease of CD31- CD34+ cells after in vitro culture using all different medium additives (HSA vs D0 p < 0.001, PL, KO, and FBS vs D0 P < 0.01). We also observed a significant increase in epithelial cells (CD326+) when the medium was supplemented with KO (vs D0 p < 0.05). Interestingly, HSA and PL showed more lymphatic endothelial cells compared to other groups (CD31 + CD34+: HSA and PL vs KO and FBS p < 0.05; CD31 + CD34 + CD90 + PDPN+: HSA and PL vs D0 p < 0.01).

CONCLUSION

Our results demonstrate that medium additives can influence the cell populations, which serve as building blocks for the engineered tissue. Therefore, according to the final application, different media can be used in vitro to favor different cell types, which will be incorporated into a functional matrix.

Tannin Reduces the Incidence of Polyspermic Penetration in Porcine Oocytes

Tannin (TA) improves porcine oocyte cytoplasmic maturation and subsequent embryonic development after in vitro fertilization (IVF). However, the mechanism through which TA blocks polyspermy after IVF remains unclear. Hence, the biological function of organelles (cortical granule [CG], Golgi apparatus, endoplasmic reticulum [ER], and mitochondria) and the incidence of polyspermic penetration were examined. We found no significant difference in oocyte nuclear maturation among the 1 µg/mL, 10 µg/mL TA, and control groups. Moreover, 100 μg/mL TA significantly reduced 1st polar body formation rate compared to the other groups. Additionally, 1 and 10 μg/mL TA significantly increased the protein levels of GDF9, BMP15, and CDK1 compared to the control and 100 μg/mL TA groups. Interestingly, 1 and 10 μg/mL TA improved the normal distribution of CGs, Golgi, ER, and mitochondria by upregulating organelle-related gene expression and downregulating ER stress (CHOP) gene expression. Simultaneously, 1 and 10 μg/mL TA significantly increased the proportion of normal fertilized oocytes (2 pronuclei; 2 PN) and blastocyst formation rate compared to the control, as well as that of 100 μg/mL TA after IVF by upregulating polyspermy-related genes. In conclusion, TA during IVM enhances 2PN and blastocyst formation rates by regulating organelles’ functions and activities.

The Improvement of Porcine In Vitro Embryo Development through Regulating Autophagy by miRNA-143 Inhibition

In vitro embryo research is an important stage for the advancement of many reproductive technologies in research and agriculture. For this reason, the improvement of in vitro embryo development is a strategic field worthy of investigation. Relatively little is known about miR-143 and its effects on autophagy associated with embryo development and in vitro embryo culture. In this study, we examined the effect of miR-143 (via mimics and inhibitors) on embryonic development threatened by microinjection after parthenogenetic activation. We evaluated rates of cleavage, blastocyst, and total cell number of blastocyst; additionally, we performed LC3 immunofluorescence analysis and mRNA expression analyses of genes associated with autophagy, endoplasmic reticulum (ER)-phagy, ER stress, embryo quality, and apoptosis. The inhibition of miR-143 positively influenced embryo development by increasing the activity of autophagy and ER-phagy and the expression of embryo quality-related genes, while reducing apoptosis. In contrast, treatment with miR-143 mimics increased ER stress-related gene expression and apoptosis, and reduced embryo development. Together, our findings indicate that miR-143 plays a role in the interplay between autophagy, ER-phagy, and embryo quality during early porcine embryo development.

Copper deficiency affects the developmental competence of porcine oocytes matured in vitro

The trace element Cu is required for the activity of various enzymes essential for physiological processes. In this study, we elucidated the copper transport system in porcine follicular cells and investigated the effect of Cu chelation during in vitro maturation (IVM) of porcine oocytes and subsequent embryonic development after parthenogenetic activation (PA). Cu chelation was induced by adding tetraethylenepentamine (TEPA) to the maturation media (TCM199-PVA). First, we identified the localization and relative levels of the copper transporter CTR1 in follicular cells. The level of CTR1 protein was the highest in mature cumulus cells; moreover, CTR1 was mainly localized in the cytoplasmic vesicular compartment in oocytes, whereas it was evenly distributed in the cytoplasm in cumulus cells. A total of 42 h after IVM, the TEPA-treated group showed reduced maturation rates compared to those of the control (p < 0.05). This negative effect of TEPA disappeared when it was added to the media with Cu (Cu + TEPA group). The TEPA treatment during IVM significantly increased the mRNA levels of the Has2 gene, which is related to cumulus expansion (p < 0.05). Both Cu supplementation and chelation significantly increased the reactive oxygen species (ROS) levels in porcine oocytes (p < 0.05). When we analyzed the transcript levels of folliculogenesis-related genes in Cu chelation conditions, only the expression of MAPK3 in cumulus cells significantly increased compared to that of the control. We also evaluated the subsequent embryonic development of PA embryos. TEPA-treated oocytes showed significantly decreased blastocyst formation rates compared to those of the control. The TEPA-induced toxic effect was alleviated when Cu was added with TEPA. Our findings suggest that the Cu transport system plays an important role in the porcine follicular development process and that the Cu deficiency negatively affects porcine oocyte maturation, as well as their subsequent developmental competence.

Ramelteon Reduces Oxidative Stress by Maintenance of Lipid Homeostasis in Porcine Oocytes

This study aimed to determine the underlying mechanism of ramelteon on the competence of oocyte and subsequent embryo development in pigs during in vitro maturation (IVM). Our results showed that the cumulus expansion index was significantly lower in the control group compared to the ramelteon groups (p < 0.05). Moreover, supplementation of 10−11 and 10−9 M ramelteon significantly increased the cumulus expansion and development-related genes expression, and reduced apoptosis in cumulus cells (p < 0.05). In oocytes, the nuclear maturation rate was significantly improved in 10−11, 10−9, and 10−7 M ramelteon groups compared to the control (p < 0.05). Additionally, the level of intracellular GSH was significantly increased and ROS was significantly decreased in ramelteon-supplemented groups, and the gene expression of oocyte development and apoptosis were significantly up- and down-regulated by 10−11 and 10−9 M ramelteon (p < 0.05), respectively. The immunofluorescence results showed that the protein levels of GDF9, BMP15, SOD1, CDK1, and PGC1α were significantly increased by 10−11 M ramelteon compared to the control (p < 0.05). Although there was no significant difference in cleavage rate, the blastocyst formation rate, total cell numbers, and hatching/-ed rate were significantly improved in 10−11 M ramelteon group compared to the control (p < 0.05). Furthermore, embryo development, hatching, and mitochondrial biogenesis-related genes were dramatically up-regulated by 10−11 M ramelteon (p < 0.05). In addition, the activities of lipogenesis and lipolysis in oocytes were dramatically increased by 10−11 M ramelteon compared to the control (p < 0.05). In conclusion, supplementation of 10−11 M ramelteon during IVM improved the oocyte maturation and subsequent embryo development by reducing oxidative stress and maintenance of lipid homeostasis.

Idebenone relieves the damage of heat stress on the maturation and developmental competence of porcine oocytes

The reproductive function of animals is often affected by climatic conditions. High-temperature conditions can cause damage to oocyte maturation and embryonic development in a variety of ways. The purpose of this study was to prove that supplementation idebenone (IDB) to the maturation medium can improve the maturation and development of porcine oocytes after heat stress (HS). Porcine cumulus-oocyte complexes (COCs) were cultured in the maturation medium with different concentrations of IDB (0, 0.1, 1 and 10 μM) for 44 hr at either 38.5°C or under the HS conditions. The cumulus oophorus expansion, nuclear maturation and blastocyst rate after parthenogenetic activation (PA) were measured. We found that HS (in vitro maturation 20-24 hr, 42°C) exposure significantly reduced cumulus expansion index and maturation rate of oocytes and the blastocyst rate of PA embryos, while IDB supplementation significantly improved oocyte maturation and development to the blastocysts stage after PA. Moreover, the addition of IDB decreased the intracellular level of ROS and increased GSH content, hence enhancing the antioxidant capacity of oocytes under HS. Meanwhile, IDB treatment also obviously improved the mitochondrial membrane potential and ATP synthesis of oocytes under HS conditions. Furthermore, IDB treatment increased the expression of GDF9 and BMP15 in IVM oocytes which attribute to improve the quality and outcome of IVM oocytes and the development competence of PA embryos in pigs. In summary, we demonstrated that IDB supplementation into the maturation medium exerted protective effects and improved the ability of maturation and developmental competence of porcine oocytes exposed to HS.

Equine Chorionic Gonadotropin as an Effective FSH Replacement for In Vitro Ovine Follicle and Oocyte Development

The use of assisted reproductive technologies (ART) still requires strategies through which to maximize individual fertility chances. In vitro folliculogenesis (ivF) may represent a valid option to convey the large source of immature oocytes in ART. Several efforts have been made to set up ivF cultural protocols in medium-sized mammals, starting with the identification of the most suitable gonadotropic stimulus. In this study, Equine Chorionic Gonadotropin (eCG) is proposed as an alternative to Follicle Stimulating Hormone (FSH) based on its long superovulation use, trans-species validation, long half-life, and low costs. The use of 3D ivF on single-ovine preantral (PA) follicles allowed us to compare the hormonal effects and to validate their influence under two different cultural conditions. The use of eCG helped to stimulate the in vitro growth of ovine PA follicles by maximizing its influence under FBS-free medium. Higher performance of follicular growth, antrum formation, steroidogenic activity and gap junction marker expression were recorded. In addition, eCG, promoted a positive effect on the germinal compartment, leading to a higher incidence of meiotic competent oocytes. These findings should help to widen the use of eCG to ivF as a valid and largely available hormonal support enabling a synchronized in vitro follicle and oocyte development.

Tannin Supplementation Improves Oocyte Cytoplasmic Maturation and Subsequent Embryo Development in Pigs

To investigate the effects of tannins (TA) on porcine oocyte in vitro maturation (IVM), different concentrations of TA (0, 1, 10 and 100 μg/mL) were supplemented with a maturation medium and the COCs and subsequent embryonic development were examined. The results showed that 10 µg/mL TA significantly improved the cumulus expansion index (CEI), cumulus-expansion-related genes (PTGS1, PTGS2, PTX-3, TNFAIP6 and HAS2) expression and blastocyst formation rates after parthenogenetic activation (PA), in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) compared to the control groups, but not oocyte nuclear maturation. Nevertheless, 10 µg/mL TA dramatically enhanced the mRNA expression of oocyte-development-related genes (BMP15, GDF9, CDC2 and CYCLIN B1), GSH, ATP, SOD1, PGC1α, BMP15, GDF9 and CDC2 levels and reduced intracellular ROS level in porcine oocytes. These results indicated that porcine oocyte cytoplasmic maturation was improved by 10 µg/mL TA treatment during IVM. In contrast, a high concentration of TA (100 μg/mL) significantly decreased the CEI and PTGS1, PTGS2, PTX-3 and HAS2 mRNA expressions in cumulus cells, and reduced oocyte nuclear maturation and the total cell numbers/blastocyst. In general, these data showed that 10 μg/mL TA supplementation has beneficial effects on oocyte cytoplasmic maturation and subsequent embryonic development in pigs.

Crosstalk between Peroxisomal Activities and Nrf2 Signaling in Porcine Embryos

Melatonin and phytanic acid (PA) are known to be involved in lipid metabolism and β-oxidation, in which peroxisomal activities also significantly participate. In addition, other studies have reported that the nuclear factor-erythroid-derived 2-like 2 (Nrf2 or NFE2L2) signaling pathway mediates lipid metabolism and its subsequent cascades. As these mechanisms are partially involved in porcine oocytes or embryonic development, we hypothesized that the factors governing these mechanisms could be interconnected. Therefore, we aimed to investigate possible crosstalk between peroxisomal activities and Nrf2 signaling in porcine embryos following melatonin and PA treatment. Porcine embryos were cultured for seven days after parthenogenetic activation, and subsequently treated with melatonin and PA, or injected with Pex19-targeted siRNAs. Real-time PCR, immunocytochemistry, and BODIPY staining were used to evaluate peroxisomal activities, Nrf2 signaling, and subsequent lipid metabolism. We found that melatonin/PA treatment enhanced embryonic development, whereas injection with Pex19-targeted siRNAs had the opposite effect. Moreover, melatonin/PA treatment upregulated peroxisomal activities, Nrf2 signaling, lipid metabolism, and mitochondrial membrane potentials, whereas most of these mechanisms were downregulated by Pex19-targeted siRNAs. Therefore, we suggest that there is a connection between the action of melatonin and PA and the Nrf2 signaling pathway and peroxisomal activities, which positively influences porcine embryonic development.

Adiponectin Improves In Vitro Development of Cloned Porcine Embryos by Reducing Endoplasmic Reticulum Stress and Apoptosis

Simple Summary

Successful attenuation of endoplasmic reticulum (ER) stress signaling has a beneficial outcome in in vitro embryonal improvement. We evaluated the effect of adiponectin during in vitro culture in porcine embryos derived from parthenogenetic activation and somatic cell nuclear transfer (SCNT). We found that 15 and 30 μg/mL adiponectin treatment significantly improved cleavage rates, blastocyst formation rates, and total cell number (TCN) of blastocysts derived from parthenogenetic activation and reduced the expression levels of XBP1. In SCNT embryos, the cleavage rate, blastocyst formation rate, and TCN of blastocysts were significantly improved by 15 μg/mL adiponectin treatment compared to the control. In addition, the 15 μg/mL adiponectin treatment reduced the levels of XBP1 expression and ER stress-related genes, increased expression levels of pluripotency-related genes, and decreased apoptosis-related gene expression. Comprehensively, treatment with 15 μg/mL adiponectin enhanced the in vitro developmental capacity of early-stage SCNT porcine embryos by reducing ER stress and apoptosis.

Abstract

The main factor of embryonic demise is endoplasmic reticulum (ER) stress. Successful attenuation of ER stress results in an improvement in embryo development. We studied the impact of adiponectin in the in vitro culture (IVC) of porcine embryos derived from parthenogenetic activation and somatic cell nuclear transfer (SCNT). The first experiment revealed that 15 and 30 μg/mL adiponectin treatments improved cleavage, blastocyst rates, and total cell number (TCN) of parthenogenetic embryos and reduced the expression of XBP1 compared to the 5 μg/mL adiponectin treatment and control groups (p < 0.05). The second experiment showed that cleavage rate, blastocyst formation rate, and TCN of blastocysts were improved in the 15 μg/mL adiponectin treatment group compared with the control group, with significantly reduced XBP1 expression in ≥4-cell stage SCNT embryos and blastocysts (p < 0.05). Treatment with 15 μg/mL adiponectin significantly improved the expression of XBP1 and reduced the expression of ER stress-related genes (uXBP1, sXBP1, PTPN1, and ATF4), increased the expression levels of pluripotency-related genes (Nanog and SOX2), and decreased apoptosis-related gene expression (Caspase-3). These results suggest that 15 μg/mL adiponectin enhanced the in vitro developmental capacity of early-stage SCNT porcine embryos by reducing ER stress and apoptosis.

Effect of Klotho protein during porcine oocyte maturation via Wnt signaling

Klotho protein is well-known as an anti-aging agent, however, several studies have suggested that Klotho protein also increases antioxidant activity and the reproductive system, as Klotho protein is closely associated with Wnt signaling. The objective of our study was to investigate the enhancement of porcine oocyte in vitro maturation via the Klotho protein-Wnt signaling pathway. Following immunohistochemistry and ELISA, we treated cells with Klotho protein during in vitro maturation. Lithium Chloride, a specific activator of Wnt signaling, was subsequently co-administered with Klotho protein. Mature oocytes subjected to treatments were used for the analysis of embryonic development, qRT-PCR, and immunocytochemistry. Treatment with 5pg/ml Klotho protein significantly increased cumulus cell expansion, blastocyst formation rates, and the total cell number of blastocysts. During cotreatment with 5mM Lithium Chloride and 5pg/ml Klotho protein, blastocyst formation rates were the highest in Klotho protein-treated oocytes and the lowest in Lithium Chloride-treated oocytes. Expression levels of Wnt signaling-related transcripts and proteins were significantly impacted by Klotho protein and Lithium Chloride. Moreover, cellular ATP levels and antioxidant activities were enhanced by Klotho protein treatment. These findings suggest a significant involvement of the Klotho protein-Wnt signaling mechanism in porcine oocyte maturation.

In Vitro and In Vivo Interspecies Chimera Assay Using Early Pig Embryos

Chimeric pigs harboring organs derived from human stem cells are promising for patient-specific regenerative therapies. Induced pluripotent stem cells (iPSCs) can contribute to all cell types of the fetus, including germline after injection into embryos. However, ethical concerns prohibit testing human iPSCs in chimera assays. Here, we evaluated porcine embryos as hosts for an interspecies chimera assay using iPSCs from either cynomolgus monkeys (cyiPSCs) or mouse (miPSCs). To establish an in vitro culture system compatible for cyiPSCs and porcine embryos, we determined blastocyst development in eight different stem cell media. The highest developmental rates of blastocysts were achieved in Knockout Dulbecco's modified Eagle's medium with 20% knockout serum replacement. We found that cyiPSCs injected into porcine embryos survived in vitro and were mostly located in the trophectoderm (TE). Instead, when miPSCs were injected into porcine embryos, the cells rapidly proliferated. The behavior of chimeras developed in vitro was recapitulated in vivo; cyiPSCs were observed in the TE, but not in the porcine epiblast. However, when miPSCs were injected into in vivo derived porcine embryos, mouse cells were found in both, the epiblast and TE. These results demonstrate that porcine embryos could be useful for evaluating the interspecies chimera-forming ability of iPSCs from different species.

Baicalin improves IVM of pig oocytes and subsequent preimplantation embryo development by inhibiting apoptosis

Baicalin, a monomer of flavonoids extracted from dried roots of Scutellaria baicalensis, is used to treat female infertility. However, the effect of baicalin on oocyte maturation is unknown. In this study we investigated the effects of baicalin on the IVM of pig oocytes and subsequent embryo development following parthenogenetic activation (PA). We found that 0.1µgmL-1 baicalin significantly (P<0.05) increased the IVM rate of oocytes compared with the non-treatment (control) group by reducing levels of reactive oxygen species (ROS). In addition, the mRNA expression of genes related to nuclear maturation and cumulus cell expansion, mitochondrial membrane potential and ATP content was significantly (P<0.05) higher in baicalin-treated than control oocytes. To determine whether baicalin treatment during IVM of pig oocytes improves subsequent development of PA embryos, we measured the cleavage and blastocyst formation rates, as well as the number of cells per blastocyst. All these parameters were significantly (P<0.05) higher in the baicalin-treated than control group. In conclusion, this study demonstrates that baicalin improves pig oocyte maturation and subsequent embryo development invitro by inhibiting production of ROS and reducing apoptosis in oocytes.

Supplementation of culture medium with knockout serum replacement improves the survival of bovine secondary follicles when compared with other protein sources during in vitro culture

The present study evaluated the effect of knockout serum replacement (KSR), fetal bovine serum (FBS) and bovine serum albumin (BSA) on the viability and growth of bovine secondary follicles cultured in vitro for 12 days. To this end, secondary follicles were isolated (185-202 μm) and cultured in vitro in TCM-199+ medium supplemented with KSR (5% and 10%), FBS (5% and 10%) or BSA (3 mg/ml) at 38.5°C with 5% CO2 in air. Follicular diameters were evaluated on days 0, 4, 8 and 12. After 12 days of culture, follicular survival analysis was performing by using calcein-AM and ethidium homodimer. Before and after culture, follicles were fixed in paraformaldehyde for histological evaluation. Follicular diameter at different days of culture were compared using the Kruskal-Wallis test, while the percentages of viable follicles were analyzed by chi-squared test (P < 0.05). Results showed that follicles cultured in the presence of KSR at both concentrations presented higher follicular survival rates than those cultured in control medium alone or supplemented with FBS or BSA. Conversely, the presence of KSR, BSA or FBS did not increase follicular diameter after 12 days of culture. Histology analysis showed that, among the tested treatments, follicles cultured in the presence of KSR had preserved rounded oocytes, juxtaposed granulosa cells and intact basal membrane. In conclusion, supplementation of culture medium with KSR increases the follicular survival of bovine secondary follicles cultured in vitro.