Project description:Exosomes and microvesicles (i.e., extracellular vesicles; EVs) have been identified within ovarian follicular fluid, and recent evidence suggests that EVs are able to elicit profound effects on ovarian cell function. While existence of miRNA within EVs has been reported, it remains unknown if EV size and concentration as well as their cargos (i.e., proteins and RNA) change during antral follicle growth. Extracellular vesicles isolated from follicular fluid of small, medium and large bovine follicles were similar in size, while concentration of EVs decreased progressively as follicle size increased. Electron microscopy indicated a highly purified population of the lipid bilayer enclosed vesicles that were enriched in exosome biomarkers including CD81 and Alix. Small RNA sequencing identified a large number of known and novel miRNAs that changed in the EVs of different size follicles. Ingenuity Pathway Analysis (IPA) indicated that miRNA abundant in small follicle EV preparations were associated with cell proliferation pathways, while those miRNA abundant in large follicle preparations were related to inflammatory response pathways. These studies are the first to demonstrate that EVs change in their levels and makeup during antral follicle development and point to the potential for a unique vesicle-mediated cell-to-cell communication network within the ovarian follicle. Examination of small RNA population in bovine follicular fluid extracellular vesicles isolated from antral follicles
Project description:Exosomes and microvesicles (i.e., extracellular vesicles; EVs) have been identified within ovarian follicular fluid, and recent evidence suggests that EVs are able to elicit profound effects on ovarian cell function. While existence of miRNA within EVs has been reported, it remains unknown if EV size and concentration as well as their cargos (i.e., proteins and RNA) change during antral follicle growth. Extracellular vesicles isolated from follicular fluid of small, medium and large bovine follicles were similar in size, while concentration of EVs decreased progressively as follicle size increased. Electron microscopy indicated a highly purified population of the lipid bilayer enclosed vesicles that were enriched in exosome biomarkers including CD81 and Alix. Small RNA sequencing identified a large number of known and novel miRNAs that changed in the EVs of different size follicles. Ingenuity Pathway Analysis (IPA) indicated that miRNA abundant in small follicle EV preparations were associated with cell proliferation pathways, while those miRNA abundant in large follicle preparations were related to inflammatory response pathways. These studies are the first to demonstrate that EVs change in their levels and makeup during antral follicle development and point to the potential for a unique vesicle-mediated cell-to-cell communication network within the ovarian follicle.
Project description:Follicles of polycystic ovaries (PCO) often become arrested in early antral stages at around 3 to 11 mm in diameter. The condition disturbs dominant follicle selection and may result in altered ovulation and anovulation. During the growth and development of human follicles, the follicular fluid (FF) constitutes the avascular microenvironment in which the oocyte develops and acts as a vehicle for hormone signaling between cues from circulation and follicular cells. Previous proteomics studies performed on FF from women with polycystic ovarian syndrome (PCOS) have revealed information on the protein changes associated with the pathophysiology of this disorder. However, these studies have been conducted on FF samples obtained in connection with oocyte pick-up during ovarian stimulation right at the time of ovulation and are limited to follicular conditions during the follicular phase of the menstrual cycle. This study aimed to detect proteomic alterations in FF from human small antral follicles (hSAF) obtained from women with PCO as compared to normal women.
Project description:Human ovarian follicles develop a fluid-filled antrum when they reach a diameter of around 250 µm. The antrum contains follicular fluid (FF) composed of secretions from cells in the follicle and from circulation. The composition of FF undergoes massive changes in relation to follicular development. Previously, only FF from large pre-ovulatory follicles aspirated just prior to ovulation, has been analyzed by proteomics; resulting in a high proportion of plasma proteins being detected due to diffusion of proteins through the increasingly leaky basal membrane in larger follicles. We present the first proteomics analysis of FF from normal unstimulated human small antral ovarian follicles (diameter: 3-8mm) identifying the largest number of proteins reported in human FF to date: 2,050 proteins of which 1,151 were identified for the first time in human FF by mass spectrometry. Furthermore, an identified growth factor, midkine, was shown to impact follicular regulatory processes including enhancement of nuclear maturation of immature human oocytes.
Project description:Granulosa cells mature and die as ovarian follicles enlarge and die (undergo atresia) under the influence of hormones and intrafollicular factors. Later in follicular development, a fluid-filled antrum is formed, a process which is accompanied by a high rate of atresia. These small antral follicles (5 mm or less in diameter in the cow) contain granulosa of 2 different phenotypes, rounded or columnar, whereas follicles larger than 5 mm have the rounded phenotype only. Prior to ovulation, in larger follicles greater than 10 mm in size, the granulosa begin to migrate and differentiate in preparation for oocyte release and formation of the corpus luteum. These two key phases of follicular development were studied by gene expression microarray analysis using a bovine model to dissect the molecular mechanisms underlying these processes.
Project description:Antral follicle size might be a valuable additive predictive marker for IVF outcome. However, while some studies show positive relations between follicle size and reproductive outcome, others have not been successful in establishing this relation. To better understand consequences of antral follicle size for reproductive outcome, we aimed to obtain insight in follicle size-related granulosa cell processes, as granulosa cells play an essential role in follicular development via the production of growth factors, steroids and metabolic intermediates, needed for follicular growth and oocyte development. Using pigs as a model, we compared gene and protein expression in granulosa cells of smaller and larger follicles in the healthy antral follicle pool at the start of the follicular phase of the estrous cycle. In sows, the early antral follicle pool is very heterogeneous when e.g. size and steroid content of the follicular fluid are considered. To which extent this variety contributes to the developmental competence of the follicles is not clear. Therefore, sows with high variation in antral follicle size (HighVAR) as well as sows with low variation in antral follicle size (LowVAR) were used. Granulosa cells of smaller antral follicles in the healthy antral follicle pool show increased cell proliferation, which was accompanied by a metabolic shift towards aerobic glycolysis (i.e. the Warburg effect), similar to other highly proliferating cells. High granulosa cell proliferation rates in smaller follicles might be regulated via increased granulosa cell expression of AR and EGFR which are activated in response to locally produced mitogens. While granulosa cells of smaller follicles in the pool were more proliferative, indicative of higher follicular growth, granulosa cells of larger follicles in the pool showed less proliferation and were more differentiated, as they showed a higher expression of follicular maturation marker IGF1 and ANGPT1. Our results imply that the inclusion of strict criteria of antral follicle size in IVF protocols might improve reproductive outcome. In addition, we have granulosa cell gene expression of healthy follicles to unravel underlying mechanisms of differences in COC morphology. We compared gene expression in sows with low vs. high-COC-health and found a decreased expression of genes involved in ovarian steroidogenesis (e.g. CYP19A1, ADM, SPP1) and higher expression of genes involved in follicular atresia (e.g. GADD45A, INHBB) in sows with low-COC-health. Thereby we have identified several genes which may serve as markers for follicle developmental competence.
Project description:Protein composition of human ovarian follicular fluid (FF) constitutes the microenvironment for oocyte development. Several proteomics studies of FF from pre-ovulatory follicles have revealed insights on oocyte maturation, however, there is a lack of knowledge on changes produced at protein levels in the FF of human small antral follicles (hSAF) related to the upcoming oocyte maturation. Using mass spectrometry-based proteomics, we evaluated the protein composition of FF that surrounds oocytes capable to reach metaphase II (MII) after IVM with the protein profile of FF that surrounds immature oocytes. The samples were collected from small antral follicles (size 6.0 ± 1.5 mm) extracted from six women, from which two or three samples were extracted. The comparison was based on both, a multivariate (sPLS-DA) and univariate analyses (t-test).
Project description:Granulosa cells mature and die as ovarian follicles enlarge and die (undergo atresia) under the influence of hormones and intrafollicular factors. Later in follicular development, a fluid-filled antrum is formed, a process which is accompanied by a high rate of atresia. These small antral follicles (5 mm or less in diameter in the cow) contain granulosa of 2 different phenotypes, rounded or columnar, whereas follicles larger than 5 mm have the rounded phenotype only. Prior to ovulation, in larger follicles greater than 10 mm in size, the granulosa begin to migrate and differentiate in preparation for oocyte release and formation of the corpus luteum. These two key phases of follicular development were studied by gene expression microarray analysis using a bovine model to dissect the molecular mechanisms underlying these processes. Four groups of bovine ovarian follicles were selected for analysis. Follicle size, type and array number for each group are as follows: small (3-5 mm) healthy rounded (n=5), small healthy columnar (n=5), atretic (n=5) and large healthy (>10 mm; n=4). For each group, the RNA from a single follicle was used to hybridise an array, except for 3 small healthy samples which were pooled from 2 follicles each due to low RNA.