5 Extracellular vesicles’ miRNAs from the oviduct and uterus modulate signalling pathways related to bovine early embryo development
R. Mazzarella A , C. L. V. Leal B , K. Cañón-Beltrán A C , Y. N. Cajas A , A. Gutiérrez-Adán A , E. M. González D , J. C. da Silveira B and D. Rizos AA Department of Animal Reproduction, INIA-CSIC, Madrid, Spain
B Department of Veterinary Medicine, FZEA-USP, Pirassununga, San Pablo, Brazil
C Department of Biochemistry and Molecular Biology, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain
D Department of Anatomy and Embryology, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain
Reproduction, Fertility and Development 35(2) 127-127 https://doi.org/10.1071/RDv35n2Ab5
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Regulation of signalling pathways for cell differentiation, proliferation, and metabolism is crucial for early embryo development and can determine the success or failure of the pregnancy. Bioactive molecules within extracellular vesicles (EVs) in maternal reproductive fluids may contribute to this regulation. MicroRNAs (miRNAs) are present in the EVs and regulate gene expression and signalling pathways through posttranscriptional mechanisms. In this study, we investigated the miRNA cargo of EVs from bovine oviducal (OF) and uterine fluids (UF) and its possible influence on crucial pathways for early embryo development. Based on corpus luteum morphology, bovine oviducts in the early luteal phase and uteri in the mid-luteal phase, which coincide with early embryo development in vivo, were collected from slaughtered cyclic heifers to obtain OF and UF. EVs were isolated by size-exclusion chromatography, and the levels of 382 miRNAs in OF-EVs (n = 3) and UF-EVs (n = 3) were determined by RT-qPCR (miSCRIPT II RT kit, Qiagen). MiRNAs with Ct < 37 were considered detected if present in at least two samples. Data were compared by Student’s t-test at 5% of significance. The miRWalk 3.0 database was used for bioinformatics analyses. A total of 333 miRNAs were detected, with 11 exclusive to OF-EVs, 59 to UF-EVs, and 263 commonly present in both groups. 20 were differentially expressed: 19 upregulated in UF-EVs and one in OF-EVs. These miRNAs were predicted (P ≤ 0.05) to modulate several signalling pathways. In OF-EVs, exclusive miRNAs modulate 14 paths related to metabolism (6) and embryo development, such as Hedgehog. In UF-EVs, exclusive miRNAs also modulate paths related to metabolism (13) and embryo development, such as TGF-β and Notch. Additionally, 27 paths are modulated by miRNAs upregulated in UF-EVs and are related to hormones and growth factors (8), inflammation and immune system (5), and paths related to apoptosis and proliferation, such as Apelin. Considering only the top 15 pathways ranked by P-value in each group, miRNAs exclusive to OF-EVs modulate paths such as actin cytoskeleton, tight junction, and focal adhesion, and their upregulated miRNAs modulate metabolism paths such as AMPK. miRNAs exclusive to UF-EVs modulate development paths such as MAPK, Rap1, and Hippo, while those upregulated also modulate development paths such as mTOR. Moreover, critical paths for embryonic cell fate, proliferation, survival, and growth, such as RAS and WNT, although predicted to be modulated by miRNAs in both OF- and UF-EVs, may undergo distinct modulation patterns as different miRNA-mRNA interactions are observed in each group. In conclusion, OF- and UF-EVs have different miRNA profiles, which modulate distinct pathways for embryo development, while UF-EVs miRNAs are related to the immune system and implantation. Understanding the expression pattern of miRNAs in OF- and UF-EVs and their predicted function may help unveil signals that the embryo is receiving from the maternal side at different stages of early development.
