MicroRNA-148b secreted by bovine oviductal extracellular vesicles enhance embryo quality through BPM/TGF-beta pathway.

BACKGROUND: Extracellular vesicles (EVs) and their cargoes, including MicroRNAs (miRNAs) play a crucial role in cell-to-cell communication. We previously demonstrated the upregulation of bta-mir-148b in EVs from oviductal fluid of cyclic cows. This miRNA is linked to the TGF-ß pathway in the cell proliferation. Our aim was to verify whether miR-148b is taken up by embryos through gymnosis, validate its target genes, and investigate the effect of miR-148b supplementation on early embryo development and quality. METHODS: Zygotes were cultured in SOF + 0.3% BSA (Control) or supplemented with: 1 µM miR-148b mimics during: D1-D7 (miR148b) or D1-D4 (miR148b-OV: representing miRNA effect in the oviduct) or D4-D7 (miR148b-UT: representing miRNA effect in the uterus) or 1 µM control mimics was used during: D1-D7 (CMimic). Embryos at ≥ 16-cells and D7 blastocysts (BD7) were collected to examine the mRNA abundance of transcripts linked to the TGF-ß pathway (TGFBR2, SMAD1, SMAD2, SMAD3, SMAD5, BMPR2, RPS6KB1, POU5F1, NANOG), total cell number (TC), trophectoderm (TE), and inner cell mass (ICM) were also evaluated. One-way ANOVA was used for all analyses. RESULTS: We demonstrated that miR-148b can be taken up in both 16-cell embryos and BD7 by gymnosis, and we observed a decrease in SMAD5 mRNA, suggesting it's a potential target of miR-148b. Cleavage and blastocysts rates were not affected in any groups; however, supplementation of miR-148b mimics had a positive effect on TC, TE and ICM, with values of 136.4 ± 1.6, 92.5 ± 0.9, 43.9 ± 1.3 for miR148b and 135.3 ± 1.5, 92.6 ± 1.2, 42.7 ± 0.8, for miR148b-OV group. Furthermore, mRNA transcripts of SMAD1 and SMAD5 were decreased (P ≤ 0.001) in 16-cell embryos and BD7 from miR148b and miR148b-OV groups, while POU5F1 and NANOG were upregulated (P ≤ 0.001) in BD7 and TGFBR2 was only downregulated in 16-cell embryos. pSMAD1/5 levels were higher in the miR148b and miR148b-OV groups. CONCLUSIONS: Our findings suggest that supplementation of bta-miR-148b mimics during the entire culture period (D1 - D7) or from D1 - D4 improves embryo quality and influences the TGF-ß signaling pathway by altering the transcription of genes associated with cellular differentiation and proliferation. This highlights the importance of miR-148b on embryo quality and development.

MicroRNA-148b secreted by bovine oviductal extracellular vesicles enhance embryo quality through BPM/TGF-beta pathway

Background Extracellular vesicles (EVs) and their cargoes, including MicroRNAs (miRNAs) play a crucial role in cell-to-cell communication. We previously demonstrated the upregulation of bta-mir-148b in EVs from oviductal fluid of cyclic cows. This miRNA is linked to the TGF-β pathway in the cell proliferation. Our aim was to verify whether miR-148b is taken up by embryos through gymnosis, validate its target genes, and investigate the effect of miR-148b supplementation on early embryo development and quality. Methods Zygotes were cultured in SOF + 0.3% BSA (Control) or supplemented with: 1 μM miR-148b mimics during: D1-D7 (miR148b) or D1-D4 (miR148b-OV: representing miRNA effect in the oviduct) or D4-D7 (miR148b-UT: representing miRNA effect in the uterus) or 1 μM control mimics was used during: D1-D7 (CMimic). Embryos at ≥ 16-cells and D7 blastocysts (BD7) were collected to examine the mRNA abundance of transcripts linked to the TGF-β pathway (TGFBR2, SMAD1, SMAD2, SMAD3, SMAD5, BMPR2, RPS6KB1, POU5F1, NANOG), total cell number (TC), trophectoderm (TE), and inner cell mass (ICM) were also evaluated. One-way ANOVA was used for all analyses. Results We demonstrated that miR-148b can be taken up in both 16-cell embryos and BD7 by gymnosis, and we observed a decrease in SMAD5 mRNA, suggesting it's a potential target of miR-148b. Cleavage and blastocysts rates were not affected in any groups; however, supplementation of miR-148b mimics had a positive effect on TC, TE and ICM, with values of 136.4 ± 1.6, 92.5 ± 0.9, 43.9 ± 1.3 for miR148b and 135.3 ± 1.5, 92.6 ± 1.2, 42.7 ± 0.8, for miR148b-OV group. Furthermore, mRNA transcripts of SMAD1 and SMAD5 were decreased (P ≤ 0.001) in 16-cell embryos and BD7 from miR148b and miR148b-OV groups, while POU5F1 and NANOG were upregulated (P ≤ 0.001) in BD7 and TGFBR2 was only downregulated in 16-cell embryos. pSMAD1/5 levels were higher in the miR148b and miR148b-OV groups. Conclusions Our findings suggest that supplementation of bta-miR-148b mimics during the entire culture period (D1 - D7) or from D1 - D4 improves embryo quality and influences the TGF-β signaling pathway by altering the transcription of genes associated with cellular differentiation and proliferation. This highlights the importance of miR-148b on embryo quality and development.

Ascorbic acid-cyclodextrin complex alters the expression of genes associated with lipid metabolism in bovine in vitro produced embryos.

Ascorbic acid (AC) used as antioxidant in embryo culture is very sensitive and degrades unavoidably in aqueous solution. Methyl-ß-cyclodextrin (CD) improved the stability of AC in solution to elevated temperature, light, humidity and oxidation. The aim of this study was to evaluate the effect of the complex AC-CD during in vitro maturation (IVM) or in vitro culture (IVC) on oocyte developmental competence and subsequent embryo development and quality. AC-CD (100 µM) was added to IVM media, and maturation level and embryo development were examined. Matured oocytes, their cumulus cells and produced blastocysts were snap-frozen for gene expression analysis by RT-qPCR. Besides, in vitro-produced zygotes were cultured with 100 µM of AC-CD and blastocysts were as well snap-frozen for gene expression analysis. A group without AC-CD (control- ) and other with CD (control+ ) were included. No differences were found on maturation, cleavage or blastocyst rates. However, in matured oocytes, AC-CD downregulated BAX, GPX1 and BMP15. In cumulus cells, AC-CD downregulated BAX/BCL2 and GSTA4 while upregulated BCL2 and CYP51A1. The expression of SL2A1, FADS1, PNPLA and MTORC1 was downregulated in blastocysts derived from oocytes matured with AC-CD, while in blastocysts derived from zygote cultured with AC-CD, CYP51A1 and IGF2R were downregulated and PNPLA2 was upregulated. In conclusion, AC-CD in both IVM and IVC media may reduce accumulated fat by increasing lipolysis and suppressing lipogenesis in blastocysts derived from both oocytes and zygotes cultured with AC-CD, suggesting that CD improves the quality of embryos and bioavailability of AC during IVM and IVC.

Effects of synchronous and asynchronous embryo transfer on postnatal development, adult health, and behavior in mice.

Asynchronous embryo transfer (ET) is a common assisted reproduction technique used in several species, but its biological effects on postnatal and early development remain unknown. The aim of this study was to determine whether asynchronous ET produces long-term effects in mice. Postnatal development, animal weight, systolic blood pressure (SBP), relative organ weight (liver, spleen, kidneys, heart, lungs, brain, and testicles), and behavior (assessed in open-field and elevated plus maze tests) were assessed in CD1 mice produced by different ET procedures: 1) the transfer of Day 3.5 (D3.5) blastocysts to the uterus (BL-UT); 2) the transfer of D3.5 blastocysts to the oviduct (BL-OV); or 3) the transfer of D0.5 zygotes to the oviduct (Z-OV). In vivo conceived animals served as controls (CT). The transfer of blastocysts to the uterus or zygotes to the oviduct was defined as synchronous, and transfer of blastocysts to the oviduct was defined as asynchronous. Both synchronous and asynchronous ET resulted in increased weight at birth that normalized thereafter with the exception of asynchronous ET females. In this group, female BL-OV, a clear lower body weight was recorded along postnatal life when compared with controls (P < 0.05). No effects on animal weight were produced during postnatal development in the synchronous ET groups (BL-UT, Z-OV, and CT). Both synchronous and asynchronous ET had impacts on adult (Wk 30) organ weight. SBP was modified in animals derived from blastocyst but not zygote ET. Effects on behavior (anxiety in the plus maze) were only detected in the BL-UT group (P < 0.05). Our findings indicate that zygotes are less sensitive than blastocysts to ET and that both synchronous and asynchronous blastocyst ET may have long-term consequences on health, with possible impacts on weight, arterial pressure, relative organ weight, and behavior.

Transgénesis mediada por espermatozoides en la especie porcina: efecto de la presencia de ADN exógeno sobre la calidad seminal y evaluación de la producción in vivo de embriones transgénicos / Sperm mediated gene transfer in pigs: Effect of exogenous DNA presence in seminal quality and evaluation of in vivo transgenic embryo production

Una alternativa biotecnológica para la producción de animales transgénicos es la transgénesis mediada por espermatozoides (SMGT), basada en la habilidad de las células espermáticas de unir e interiorizar ADN exógeno. En este estudio se plantearon dos objetivos principales: 1) evaluar el efecto de la presencia de ADN exógeno sobre la calidad seminal y 2) evaluar la eficiencia en la producción de embriones transgénicos porcinos in vivo mediante inseminación intrauterina quirúrgica con espermatozoides incubados con el transgén. Para alcanzar estos objetivos, los espermatozoides (libres de plasma seminal) fueron incubados en presencia del transgén EGFP (proteína verde fluorescente) durante 2 h a 16°C (en una relación de 10(8) cels/mL y 5 µg ADN/mL). Se valoró la motilidad, motilidad progresiva e integridad de membrana de los espermatozoides incubados, en presencia o ausencia del transgén. Los resultados mostraron que la presencia del ADN no afectó a ninguno de los parámetros seminales estudiados. Con muestras seminales incubadas con el transgén se llevaron a cabo inseminaciones intrauterinas mediante laparotomía en 4 hembras prepúberes. A los 6-7 días tras la inseminación se recolectaron los embriones, para evaluar la tasa de fecundación y la expresión de la proteína verde fluorescente EGFP en los mismos. El número medio de cuerpos lúteos por cerda fue de 10,50 ± 2,90 con una tasa de recolección de 11,90%. Se recolectó un total de 5 embriones presentando todos ellos un estado normal de desarrollo y una alta calidad (dos de ellos presentaban más de 400 células por embrión). Cuando fue analizada la expresión mediante microscopia de fluorescencia, ninguno de ellos expresaba la proteína EGFP. Este resultado, bajo las condiciones experimentales del presente estudio, podría indicar que el transgén se una en su mayoría a espermatozoides con baja viabilidad por lo que la probabilidad de que los espermatozoides vivos unan el ADN y sean capaces de fecundar en comparación con espermatozoides sin el transgén es realmente baja.

An alternative technology for producing transgenic animals is sperm mediated gene transfer (SMGT), based on the ability of sperm cells to bind and internalize exogenous DNA. The aims of this work were: 1) evaluate the effects of the presence of exogenous DNA in the seminal quality and 2) evaluate the efficiency of transgenic embryos production by surgery artificial insemination using sperm mediated gene transfer technique. Fresh spermatozoa (removed seminal plasma) were incubated with DNA (EGFP) at 16°C for 2 h (10(8) cells/mL and 5 µg DNA/mL). At first motility, progressive motility and viability were evaluated in spermatozoa incubated with or without exogenous DNA. The results showed that the presence of the DNA did not affect any of the studied sperm parameters (motility, progressive motility and viability). On the other hand insemination was carried out in 4 gilts by laparotomy in utero tubaric junction. Six-seven days after insemination blastocysts were collected and fertilization rate and transgene expression were determined. The mean number of corpora lutea/gilt was 10.50 ± 2.90 with a mean recovery rate of 11.90%. After the surgery, a total of 5 embryos were recovered and the percentage of normally developed embryos was 100% and with a high quality (two of them had more than 400 cells). When the blastocysts recovered after 6-7 days post-insemination were analyzed by fluorescence microscopy, it was revealed that none of them expressed protein EGFP. These results show the possibility that exogenous DNA bound to the sperm with low viability and only a low percentage to viable sperm, so the probability that live sperm bind the DNA and are able to fertilize in comparison with live sperm without the transgene are really low.