Cell-secreted vesicles in equine ovarian follicular fluid contain miRNAs and proteins: a possible new form of cell communication within the ovarian follicle.

The research is a study examining whether small cell-secreted vesicles found in the ovarian follicular fluid of horses contain microRNAs and proteins, which could represent a new form of cell communication. Comparisons were also made based on the age of the horse.

Research Overview

The researchers aimed to understand the mechanisms of cell communication within the equine ovarian follicle, which is crucial for a healthy oocyte to develop into an embryo. The communication process involves signaling molecules and can be influenced by maternal age. Previous research hinted at the cell communication being mediated through the secretion and uptake of small vesicles enclosed by the membrane.

Research Goals

• Identify cell-secreted vesicles carrying microRNAs and proteins within the ovarian follicular fluid;
• Discover if the level of microRNAs varies in exosomes (a type of vesicle) isolated from the follicular fluid of young vs. old mares.

Research Methods and Findings

• Microvesicles and exosomes in ovarian follicular fluid were identified using transmission electron microscopy and flow cytometry;
• Proteomics analysis was used to show that the exosomes contain known exosomal proteins as well as proteins not previously reported in isolated exosomes;
• Real-time PCR analysis confirmed the presence of microRNAs in preparations of both microvesicles and exosomes from the follicular fluid. To further investigate this, researchers labeled microvesicles with fluorescence and observed how they were absorbed by granulosa cells;
• MicroRNA expression profiling demonstrated that the same microRNAs found in the microvesicle and exosome preparations from follicular fluid were also present in the surrounding granulosa and cumulus cells, suggesting a form of communication between them.

Impact of Age on MicroRNAs

The researchers found that the microRNAs present in the exosomes vary based on the age of the mare, identifying a difference in specific miRNAs between young and old mares’ follicular fluid.

Conclusions

The study revealed that bioactive material transfer using microvesicles and exosomes might be a form of cell communication within the mammalian ovarian follicle. This highlights a new perspective on understanding ovarian health and function, which can contribute to equine breeding and reproduction.