Seasonal environmental fluctuations alter the transcriptome dynamics of oocytes and granulosa cells in beef cows.

Background: Examining the mechanistic cellular responses to heat stress could aid in addressing the increasing prevalence of decreased fertility due to elevated ambient temperatures. Here, we aimed to study the differential responses of oocytes and granulosa cells to thermal fluctuations due to seasonal differences. Dry beef cows (n = 10) were housed together, synchronized and subjected to a stimulation protocol to induce follicular growth before ovum pick-up (OPU).

Seasonal influence on miRNA expression dynamics of extracellular vesicles in equine follicular fluid.

Background: Ovarian follicular fluid (FF) is a dynamic environment that changes with the seasons, affecting follicle development, ovulation, and oocyte quality. Cells in the follicles release tiny particles called extracellular vesicles (EVs) containing vital regulatory molecules, such as microRNAs (miRNAs). These miRNAs are pivotal in facilitating communication within the follicles through diverse signaling and information transfer forms.

Mapping the follicle-specific regulation of extracellular vesicle-mediated microRNA transport in the southern white rhinoceros (Ceratotherium simum simum)†.

Efforts to implement effective assisted reproductive technologies (ARTs) for the conservation of the northern white rhinoceros (NWR; Ceratotherium simum cottoni) to prevent its forthcoming extinction, could be supported by research conducted on the closely related southern white rhinoceros (SWR; Ceratotherium simum simum). Within the follicle, extracellular vesicles (EVs) play a fundamental role in the bidirectional communication facilitating the crucial transport of regulatory molecules such as microRNAs (miRNAs) that control follicular growth and oocyte development. This study aimed to elucidate the dynamics of EV-miRNAs in stage-dependent follicular fluid (FF) during SWR ovarian antral follicle development.

MicroRNA Nano-Shuttles: Engineering Extracellular Vesicles as a Cutting-Edge Biotechnology Platform for Clinical Use in Therapeutics.

Extracellular vesicles (EVs) are nano-sized, membranous transporters of various active biomolecules with inflicting phenotypic capabilities, that are naturally secreted by almost all cells with a promising vantage point as a potential leading drug delivery platform. The intrinsic characteristics of their low toxicity, superior structural stability, and cargo loading capacity continue to fuel a multitude of research avenues dedicated to loading EVs with therapeutic and diagnostic cargos (pharmaceutical compounds, nucleic acids, proteins, and nanomaterials) in attempts to generate superior natural nanoscale delivery systems for clinical application in therapeutics. In addition to their well-known role in intercellular communication, EVs harbor microRNAs (miRNAs), which can alter the translational potential of receiving cells and thus act as important mediators in numerous biological and pathological processes.

Bovine oviductal organoids: a multi-omics approach to capture the cellular and extracellular molecular response of the oviduct to heat stress.

Background: The mammalian oviduct is a complex, fibromuscular organ known for its role in orchestrating a series of timely and dynamic changes to suitably support early embryogenesis. Climate change-induced heat stress (HS) is one of the largest single stressors compromising reproductive function in humans and farm animals via systemic changes in the redox status of the maternal environment, adversely affecting fertilization and early embryonic development. Oviductal organoids represent a unique 3-dimensional, biomimetic model to study the physiology of the oviduct and its subsequent impact on embryo development under various environmental conditions.

Extracellular vesicle-microRNAs mediated response of bovine ovaries to seasonal environmental changes.

Background: Among the various seasonal environmental changes, elevated ambient temperature during the summer season is a main cause of stress in dairy and beef cows, leading to impaired reproductive function and fertility. Follicular fluid extracellular vesicles (FF-EVs) play an important role in intrafollicular cellular communication by, in part, mediating the deleterious effects of heat stress (HS). Here we aimed to investigate the changes in FF-EV miRNA cargoes in beef cows in response to seasonal changes: summer (SUM) compared to the winter (WIN) season using high throughput sequencing of FF-EV-coupled miRNAs.

Granulosa cell-derived extracellular vesicles mitigate the detrimental impact of thermal stress on bovine oocytes and embryos.

Climate change-induced global warming results in rises in body temperatures above normal physiological levels (hyperthermia) with negative impacts on reproductive function in dairy and beef animals. Extracellular vesicles (EVs), commonly described as nano-sized, lipid-enclosed complexes, harnessed with a plethora of bioactive cargoes (RNAs, proteins, and lipids), are crucial to regulating processes like folliculogenesis and the initiation of different signaling pathways. The beneficial role of follicular fluid-derived EVs in inducing thermotolerance to oocytes during maturation (IVM) has been evidenced.

Dynamics of extracellular vesicle-coupled microRNAs in equine follicular fluid associated with follicle selection and ovulation.

Innumerable similarities in reproductive cyclicity and hormonal alterations highlight the considerable utility of the mare to study aspects of follicular dynamics and reproductive function in view of the largely constricted, human research subjects. The bi-directional communication between the growing oocyte and the surrounding somatic cells embodies the hallmark of mammalian follicular development, partially mediated by extracellular vesicles (EVs) encapsulated with microRNAs (miRNAs) and present in the follicular fluid (FF). Here, we aimed to decipher the dynamics of the miRNAs in EVs from equine FF aspirated in vivo during different stages of follicular development, namely, predeviation (PreDev; 18-20 mm), deviation (Dev; 22-25 mm), postdeviation (PostDev; 26-29 mm), preovulatory (PreOV; 30-35 mm), and impending ovulation (IMP; ∼40 mm).

Current knowledge and the future potential of extracellular vesicles in mammalian reproduction.

Extracellular vesicles (EVs), which contain various functional classes of vesicles, namely exosomes, microvesicles, and apoptotic bodies, represent the major nano-shuttle to transfer bioactive molecules from donor to recipient cells to facilitate cell-to-cell communication in the follicular, oviduct, and uterine microenvironments. In addition to transferring various molecular cargos in the form of miRNAs, mRNAs, proteins, lipids, and DNA molecules, the relative proportion of those molecular cargos in the reproductive fluids can be associated with the physiological and pathological condition of the host animal. Inside the follicle, EV-mediated circulation of miRNAs has been reported to be associated with the growth status of the enclosed oocytes, the metabolic status, and the advanced maternal aging of the animal.