Morphological, molecular, and functional analysis of fetal bovine serum-derived extracellular vesicles on the lipid metabolism of cumulus-oocyte complexes and embryos

• Grant number: 24/05583-9
• Support Opportunities: Scholarships in Brazil - Support Program for Fixating Young Doctors
• Start date: April 01, 2024
• End date: September 30, 2025
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Agreement: CNPq
• Principal Investigator: Cláudia Lima Verde Leal
• Grantee: Priscila Assis Ferraz
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil
• Associated research grant: 23/01524-5 - Morphological, molecular, and functional analysis of fetal bovine serum-derived extracellular vesicles on the lipid metabolism of cumulus-oocyte complexes and embryos, AP.R

Abstract

In vitro-produced bovine embryos (IVP) have morphological, molecular, and, mainly, metabolic alterations, such as lipid accumulation, which leads to lower cryotolerance. Fetal bovine serum (FBS) is among the most used sources of macromolecules in culture media during IVP. Besides, it is considered one of the main factors responsible for the increase in lipid accumulation of these structures. On the other hand, despite the harmful effects of FBS, COCs, and embryos cultured without this macromolecule have morphological and molecular changes that affect the maturation as well as early embryonic development. Interestingly, FBS has small extracellular vesicles (EVs; sfbEVs) that carry lipids, mRNA, and miRNAs. Recent studies using depleted FBS (dSFB), i.e., in which most EVs were removed, showed an improvement in embryo quality and cryotolerance, suggesting that these sfbEVs may be responsible for the negative effects on lipid metabolism in IVP embryos. Therefore, this study aims to investigate the role of sfbEVs on lipid metabolism and oxidative stress in COCs and bovine embryos during the different IVP stages. For this, in experiment 1, the miRNAs, mRNAs, and lipids in sfbEVs will be investigated to identify which of these bioactive molecules may be involved in causing negative effects in COCs and in vitro bovine embryos. Next, in experiments 2 and 3, we seek to understand which alterations in lipid metabolism and oxidative stress will be caused in COCs and embryos when they are exposed to sfbEVs during in vitro maturation and culture. At the end of this project, we expect to generate new knowledge on how the lipid metabolism of COCs and embryos may be altered by sfbEVs, which can contribute to improve the quality of in vitro-produced bovine embryos.