Small-extracellular vesicles and their microRNA cargo from porcine follicular fluids: the potential association with oocyte quality

Ahmed Gad; Matej Murin; Alexandra Bartkova; Veronika Kinterova; Katerina Marcollova; Jozef Laurincik; Radek Prochazka

doi:10.1186/s40104-022-00723-1

Small-extracellular vesicles and their microRNA cargo from porcine follicular fluids: the potential association with oocyte quality

J Anim Sci Biotechnol. 2022 Jun 20;13(1):82. doi: 10.1186/s40104-022-00723-1.

Authors

Ahmed Gad^{1

2}, Matej Murin³, Alexandra Bartkova^{1

4}, Veronika Kinterova¹, Katerina Marcollova¹, Jozef Laurincik^{1

4}, Radek Prochazka¹

Affiliations

¹ Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721, Liběchov, Czech Republic.
² Department of Animal Production, Faculty of Agriculture, Cairo University, Giza, 12613, Egypt.
³ Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721, Liběchov, Czech Republic. Murin@iapg.cas.cz.
⁴ Department of Botany and Genetics, Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, 94901, Nitra, Slovakia.

Abstract

Background: Ovarian follicular fluids (FFs) contain several kinds of regulatory factors that maintain a suitable microenvironment for oocyte development. Extracellular vesicles (EVs) are among the factors that play essential roles in regulating follicle and oocyte development through their cargo molecules that include microRNAs (miRNAs). This study aimed to investigate small-EV (s-EV) miRNAs in porcine FFs and their potential association with oocyte quality.

Methods: Individual aspirated oocytes were stained with lissamine green B stain (LB), a vital stain for oocyte quality, and each oocyte was classified as high-quality (unstained; HQ) or low-quality (stained; LQ). FFs corresponding to oocytes were pooled together into HQ and LQ groups. Small-EVs were isolated from FFs, characterized, and their miRNA cargo was identified using the Illumina NovaSeq sequencing platform. Additionally, s-EVs from the HQ and LQ groups were utilized to investigate their effect on oocyte development after co-incubation during in vitro maturation.

Results: A total of 19 miRNAs (including miR-125b, miR-193a-5p, and miR-320) were significantly upregulated, while 23 (including miR-9, miR-206, and miR-6516) were downregulated in the HQ compared to the LQ group. Apoptosis, p53 signaling, and cAMP signaling were among the top pathways targeted by the elevated miRNAs in the HQ group while oocyte meiosis, gap junction, and TGF-beta signaling were among the top pathways targeted by the elevated miRNAs in the LQ group. The supplementation of small-EVs during maturation does not affect the oocyte developmental rates. However, LQ s-EVs increase the proportion of oocytes with homogeneous mitochondrial distribution and decrease the proportion of heterogeneous distribution.

Conclusion: Our findings indicated that FF-EVs contain different miRNA cargos associated with oocyte quality and could affect the mitochondrial distribution patterns during oocyte maturation.

Keywords: Extracellular vesicles; Follicular fluids; MiRNA; Oocyte quality; Porcine.

Abstract

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