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Acta Veterinaria Hungarica
Authors: Juliana C. Z. Conceição, Marcelo T. Moura, José C. Ferreira-Silva, Pamela Ramos-Deus, Priscila G. C. Silva, Ludymila F. Cantanhêde, Ricardo M. Chaves, Paulo F. Lima, and Marcos A. L. Oliveira

Exposure of caprine oocytes and embryos to retinoids enhances embryonic development, but the mechanisms governing this phenomenon have not been characterised. The aim of the present study was to evaluate if the incidence of apoptosis is affected by the addition of retinyl acetate (RAc) and 9-cis-retinoic acid (RA) during in vitro maturation (IVM) of caprine oocytes. Embryonic development was recorded on days 3 and 8 post-fertilisation, and apoptosis was measured by caspase activity and DNA fragmentation (TUNEL assay). Control zygotes had lower capacity to cleave and reach the blastocyst stage (24.45 ± 2.32 and 5.32 ± 0.81, respectively) than those of RAc- (29.96 ± 1.62 and 7.94 ± 0.93, respectively) and RA-treated groups (30.12 ± 1.51 and 7.36 ± 1.02, respectively). Oocytes and blastocysts positive for TUNEL assay were more frequent, respectively, in the controls (8.20 ± 0.78, 8.70 ± 1.05) than in RAc (5.60 ± 0.52, 4.80 ± 0.51) and RA (6.40 ± 0.69, 5.40 ± 0.69). Caspase activity did not differ between control oocytes (7.20 ± 0.91), RAc (6.60 ± 0.68) and RA (7.30 ± 0.67), but it was reduced in RAc- (5.05 ± 0.62) and RA-treated blastocysts (5.75 ± 0.22) compared to controls (8.35 ± 0.71). These results indicate that the addition of retinoids during IVM increases the developmental potential of goat embryos with a concomitant reduction in apoptosis rates.

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Acta Veterinaria Hungarica
Authors: Ludymila F. Cantanhêde, Marcelo T. Moura, Roberta L. Oliveira-Silva, Pábola S. Nascimento, José C. Ferreira-Silva, Ana M. Benko-Iseppon, and Marcos A. L. Oliveira

Abstract

Follicle-stimulating hormone (FSH) contributes to the acquisition of oocyte competence by modulating signalling pathways in cumulus cells (CCs), albeit much less is known about transcription factors (TFs) that orchestrate the downstream transcriptional changes. This work allowed to prospect TFs involved in FSH-mediated signalling during oocyte in vitro maturation (IVM). Bovine cumulus-oocyte complexes underwent IVM with FSH (FSH+) or without FSH (control/CTL) for 22 h, and CCs were subjected to gene expression profiling. Five software identified reference genes for RT-qPCR (ATP1A1, UBB, and YWHAZ). The transcript levels of FSH-responsive genes HAS2 and PTGS2 (COX2) validated the experimental design. Among candidate TFs, MYC was down-regulated (0.35-fold; P < 0.0001), and THAP11 (RONIN) was up-regulated (1.47-fold; P = 0.016) under FSH+ conditions. In silico analyses predicted binding motifs at MYC and THAP11 genes for previously known FSH-responsive TFs. Signalling pathways (EGFR, ERK, GSK3, PKA, and P38) may execute post-translational regulation due to potential phosphorylation sites in MYC and THAP11 proteins. Prediction of protein–protein interaction networks showed MYC as a core component of FSH signalling, albeit THAP11 acts independently. Hence, MYC integrates FSH signalling networks and may assist in exploring genome-wide transcriptional changes associated with the acquisition of oocyte competence.

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