Project description:Vitrification is a method for long-term biological sample cryopreservation without causing intra- and extra-cellular ice formation. We recently established a novel closed vitrification system to cryopreserve mouse ovarian follicles. Using the 3D alginate hydrogel encapsulated in vitro follicle growth (eIVFG) method, we have demonstrated that compared to freshly-harvested follicles, vitrified follicles have normal follicle and oocyte reproductive outcomes. Our recent study further demonstrated the faithful preservation of molecular signatures of follicle-stimulating hormone (FSH)-stimulated follicle maturation in vitrified follicles. However, it is unknown whether ovulation, another crucial gonadotropin-dependent follicular event, and involved ovulatory gene regulatory pathways are well conserved in vitrified follicles. Fresh and vitrified follicles grown for 8 days by eIVFG were collected at 0, 1, 4 and 8-hour post human chorionic gonadotropin (hCG) treatment for the single-follicle RNA sequencing. Principal component analysis (PCA) and Pearson’s correlation analysis revealed that vitrified follicles have similar transcriptomic profiles to fresh follicles. Furthermore, the expression of several genes essential for ovulation were comparable between vitrified and fresh follicles. In summary, these results demonstrate that our closed vitrification system preserves follicular transcriptomic dynamics during ex vivo ovulation. Together with our previous findings that vitrification preserves FSH-stimulated follicle maturation, the integration of vitrification of immature follicles and eIVFG has a great potential to serve as an additional fertilization preservation approach for young cancer patients and endangerers species. Moreover, follicle vitrification enables a high-content ovarian follicle biobank, which can greatly improve the throughput of eIVFG for studying ovulation biology, anovulatory disease, toxicology, and novel contraceptive drug development targeting ovulation.

Project description:Vitrification is a method for long-term biological sample cryopreservation that transforms cells into a glass-like state by cooling without causing intra- and extra-cellular ice formation, which is a major driver of cell cryoinjury. Using an alginate hydrogel encapsulated in vitro follicle growth (eIVFG) system, we have recently demonstrated that compared to freshly-harvested follicles, vitrified follicles have normal follicle and oocyte reproductive outcomes as well as comparable expression levels of several genes that are essential for gonadotropin-dependent folliculogenesis and oogenesis. However, it is unknown whether vitrification preserves the molecular signatures of folliculogenesis at the whole transcriptomic level, which is the primary research focus in this study. Multilayered secondary follicles with a diameter of 130 -160 µm were mechanically isolated from 16-day-old CD-1 female mice and vitrified using the closed vitrification method. After a 2-week storage in liquid nitrogen, vitrified follicles were warmed, and together with freshly-harvested follicles, cultured for 8 days using the eIVFG method. Next, mature antral follicles from day 8 were collected for single-follicle RNA sequencing using the SMART-seq RNA-seq method. Principal component analysis (PCA) and Pearson’s correlation analysis revealed that vitrified follicles have similar transcriptomic profiles to fresh follicles. Using the criterion of fold change >2 or <0.5 and a false discovery rate (FDR) adjusted p-value < 0.05, there were 35 differentially expressed genes out of a total of 11,806 detected genes between vitrified and fresh follicles, among which 17 were up-regulated and 18 were down-regulated in vitrified follicles. To the best of our knowledge, none of those differentially expressed genes identified between vitrified and fresh follicles have been shown to be critical to folliculogenesis and oogenesis. Meanwhile, gene ontology (GO) and KEGG pathway analysis over these 35 genes using the functional annotation tool DAVID revealed that no GO terms or signaling pathways were significantly enriched. Furthermore, the expression of several genes essential for the gonadotropin-dependent folliculogenesis and oogenesis were comparable between vitrified and fresh follicles, including granulosa cell-specific genes (Cyp19a1, Amh, Inha, Inhba, Inhbb, and Fshr), theca cell-specific genes (Cyp17a1, Col1a2, and Col3a1), and oocyte-specific genes (Gdf9, Bmp15, Zp1, Zp2, and Zp3). Equally important, Lhcgr, the gene that is primarily expressed in theca cells of preantral follicles and then greatly induced in mural granulosa cells in antral follicles to prepare for the luteinizing hormone (LH) surge and ovulation, also had comparable mRNA expression levels between vitrified and fresh follicles. Taken together, these results demonstrate that vitrification preserves the follicular cell transcriptome and molecular signatures of gonadotropin-dependent folliculogenesis in the eIVFG system. In conclusion, our study re-evaluates individual follicle cryopreservation by using the closed vitrification method in a more in-depth perspective and proves that vitrification preserves the follicular cell transcriptome in the eIVFG system, thus providing a robust model for fertility preservation, conservation of endangered species, and also establishing a high-content ovarian follicle biobank for studying ovarian biology and female reproductive toxicology.

Project description:The mammalian follicular development is a well-orchestrated and complex molecular process characterized by sequences of follicular waves that yield the ovulatory follicle. It has been reported that bi-directional communication between the growing oocyte and the surrounding somatic cells is a hallmark of mammalian follicular development, partially mediated by extracellular vesicles (EVs) present in the follicular fluid (FF). Bioactive molecules such as the miRNAs encapsulated in the EVs mediate this communication within the follicular environment. Here, we aimed to decipher the dynamics of the miRNAs in the EVs of equine FF aspirated in vivo during different stages of follicular development. Hence, all follicles ≥6 mm were ablated on Days 10–11 of the estrous cycle (ovulation = Day 0) and the new induced wave was ultrasound-monitored daily until the largest growing follicle for at least three consecutive days was randomly allocated to one of the five groups (n = 8 follicles/group) 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). The FF was collected from each target group by ultrasound-guided transvaginal follicle aspiration. After removal of cells, cellular debris, and larger particles, EVs were isolated from FF groups (4 biological replicates/group; 0.5 mL FF/replicate) using high-speed ultracentrifugation (120,000xg for 70 min). Isolated EVs were characterized using western blot for EV marker proteins, NanoSight Tracking Analysis, and electron microscopy. MiRNA enriched total RNA was isolated from EVs using an Exosomal RNA Isolation kit and small-RNA library preparation and RNAseq (NextSeq500; Illumina) was performed by Novogene Co, Ltd. Approximately 180 known miRNAs were detected in each group with 148 mutually found in all groups. Among the expressed miRNAs, miR-148a, miR-21, miR-192, and miR-99a were the top highly abundant miRNAs in all groups. Cluster analysis exhibited 15 different expression patterns during follicular development. Among these patterns, a group of 23 miRNAs (including miR-106b, miR-199a-5p, and miR-125a-5p) exhibited a stable expression at the preDev until the postDev stage, a significant increase at the preOV stage, and then a significant decrease at the IMP stage. This miRNA cluster has been found to target genes involved in TGF-signaling and endocytosis pathways. Another interesting pattern with 22 miRNAs (including miR-146b-5p, miR-140, and miR-143) exhibited a sharp reduction in their expression from the preDEV until the preOV stage and was predicted to target genes associated with fatty acid biosynthesis, cell cycle, and oocyte meiosis pathways. In contrast, a group of 16 miRNAs (including miR-483, miR-128, and miR-192) gradually increased in expression from preDEV to the postDEV and then downregulated at the preOV stage. This miRNA cluster targets several signaling pathways, including ErbB, thyroid, and estrogen signaling. In conclusion, this study provides greater insights into the stage-specific expression dynamics of the FF EV-miRNAs during equine follicular development, which may play a role in folliculogenesis in mares.

Project description:Direct exposure to physiologically-relevant elevated temperatures during the first half of in vitro maturation heightens cumulus-derived progesterone production, suppresses matrix metallopeptidase 9 secretion, and alters cumulus transcriptome. We hypothesized that heat-induced perturbations in cumulus cells enveloping maturing oocyte may extend to the mural granulosa of the periovulatory follicle in the heat-stressed cow to subsequently follicular fluid proteome. Lactating Holsteins were pharmacologically stimulated to produce a dominant follicle then given GnRH to induce an LH surge. Following GnRH administration, cows were maintained at ~67 temperature humidity index (THI; thermoneutral conditions) or exposed to conditions simulating an acute heat stress event (71 to 86 THI; heat stress for ~12 h). Fluid was aspirated from periovulatory follicle ~16 h after GnRH. Follicular fluid proteome from thermoneutral (n = 5) and hyperthermic (n = 5) cows was evaluated by quantitative tandem mass spectrometry (nano LC-MS/MS). We identified 35 differentially-abundant proteins. Functional annotation revealed numerous immune-related proteins. Subsequent efforts revealed an increase in levels of the proinflammatory mediator bradykinin in follicular fluid (P = 0.0456) but not in serum (P = 0.9319) of hyperthermic cows. Intrafollicular increases in transferrin (negative acute phase protein) in hyperthermic cows (P = 0.0181) coincided with a tendency for levels to be increased in the circulation (P = 0.0683). Nine out of 15 cytokines evaluated were detected in follicular fluid. Heat stress increased intrafollicular IL6 levels (P = 0.0160). Whether hyperthermia-induced changes in the heat-stressed cow’s follicular fluid milieu reflect changes in mural granulosa, cumulus, other cell types secretions, and/or transudative changes from circulation remains unclear. Regardless of origin, heat stress/hyperthermia related changes in the follicular fluid milieu may have an impact on components important for ovulation and competence of the cumulus-oocyte complex contained within the periovulatory follicle

Project description:Gonadotropin surge acts on the preovulatory follicle of the ovary to induce luteinization of follicular cells, oocyte meiotic maturation, cumulus expansion and follicular rupture leading to ovulation. These processes are brought about by spatial and temporal changes in transcriptional regulation of genes in the follicular cells in response to the gonadotropin surge. Analysis of gene expression changes in the periovulatory follicular cells will help in delineating the signal transduction pathways involved in the above mentioned processes. In monoovulatory species like bovines, the time interval of 24-28 hours between gonadotropin surge and ovulation provides distinct advantage for studying the temporal changes in the gene expression pattern. Thus, in the present study, we attempt to identify the temporal changes in the global gene expression profile in the periovulatory follicle of buffalo cows in response to gonadotropin surge and the results suggest the involvement of Insulin-like Growth Factor 1 and cytokine signaling pathways in the periovulatory events. Experiment Overall Design: To study the periovulatory gene expression changes in buffalo cows, an induced-ovulation model system involving sequential treatment with PGF2alpha and GnRH was standardized. The follicular wave containing at least one large follicle of ~7mm size was determined by ultrasonography on day 7 of the estrous cycle before administering exogenous PGF2alpha to induce luteolysis and follicular growth. Exogenous GnRH (100Âµg i.m) was administered 36h post PGF2alpha to induce LH surge. The time course of increase in LH levels post GnRH injection was monitored. Since peak LH levels are attained 2 h post GnRH administration, the time intervals of 3 h post GnRH (corresponding to1 h post LH surge) and 24 h post GnRH (corresponding to 22 h post LH surge) were chosen to identify the gene expression profile associated with immediate early and delayed changes in periovulatory follicle respectively. Thus ovaries were collected before, 1 h and 22 h post LH surge and follicle wall and granulosa cells were isolated from the ovaries and snap frozen for the purpose of RNA isolation.

			Action	DRS
	SRR16027443_1.fastq.gz	Fastqsanger.gz
	SRR16027443_2.fastq.gz	Fastqsanger.gz
	SRR16027444_1.fastq.gz	Fastqsanger.gz
	SRR16027444_2.fastq.gz	Fastqsanger.gz
	SRR16027445_1.fastq.gz	Fastqsanger.gz

Dataset Information

Vitrification preserves murine ovarian follicular cell transcriptome in a 3D encapsulated in vitro follicle growth system

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets