Supplementation with specific miRNAs during early embryo development: A tool for improving in vitro embryo production

• Grant number: 24/07395-5
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: August 28, 2024
• End date: February 21, 2025
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Juliano Coelho da Silveira
• Grantee: Camila Azzolin de Souza
• Supervisor: Dimitrios Rizos
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil
• Institution abroad: Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Spain
• Associated to the scholarship: 22/09461-0 - Transfection of extracellular vesicles from follicular fluid with specific microRNAs: a form of miRNA delivery to bovine cumulus-oocyte complex cells, BP.MS

Abstract

Embryo development occurs within a dynamic environment, characterized by molecular exchanges between the embryo and maternal structures. However, this scenario is often disrupted in vitro, where embryos can also be cultured. Consequently, the inability to fully replicate the in vivo environment likely accounts for the reduced developmental potential observed in in vitro-produced embryos, requiring the development of novel strategies for enhancement. Recent research has focused on delivering bioactive molecules such as miRNAs to gametes and embryos in vitro, yielding promising outcomes. Furthermore, previous studies conducted by our grouphave identified alterations in miRNA expression patterns during embryo development comparing in vivo versus in vitro produced embryos, revealing notable increases inmiR-99a-5p levels in 4-cell embryos and miR-92a in 8 to 16-cell embryos produced in vivo. These miRNAs are implicated in critical signaling pathways, including Rap1 and ErbB, pivotal for early embryonic development. Guided by these findings, we propose an approach involving the initial supplementation of culture media with miR-99a-5puntil 54 h post insemination followed by the addition of miR-92a after 54 h PI up to 96 h PI to improve the quality of bovine embryos produced in vitro. Through a series of experiments involving the supplementation of the culture media with miRNAs, assessment of miRNA uptake, exploration of miRNA target gene expression, and evaluation of embryonic developmental parameters, our study aims to offer valuableinsights into improving in vitro embryo production and quality.