Correction to: Synergy of Paracrine Signaling During Early-Stage Mouse Ovarian Follicle Development In Vitro

Previous evidence fromin vitrostudies suggests specific roles for a subset of miRNAs, including miR-21, miR-23a, miR-145, miR-503, miR-224, miR-383, miR-378, miR-132, and miR-212, in regulating ovarian follicle development. The objective of this study was to determine changes in the levels of these miRNAs in relation to follicle selection, maturation, and ovulation in the monovular equine ovary. In Experiment 1, follicular fluid was aspirated during ovulatory cycles from the dominant (DO) and largest subordinate (S) follicles of an ovulatory wave and the dominant (DA) follicle of a mid-cycle anovulatory wave (n=6 mares). Follicular fluid levels of progesterone and estradiol were lower (P<0.01) in S follicles than in DO follicles, whereas mean levels of IGF1 were lower (P<0.01) in S and DA follicles than in DO follicles. Relative to DO and DA follicles, S follicles had higher (P≤0.01) follicular fluid levels of miR-145 and miR-378. In Experiment 2, follicular fluid and granulosa cells were aspirated from dominant follicles before (DO) and 24 h after (L) administration of an ovulatory dose of hCG (n=5 mares/group). Relative to DO follicles, L follicles had higher follicular fluid levels of progesterone (P=0.05) and lower granulosa cell levels ofCYP19A1andLHCGR(P<0.005). Levels of miR-21, miR-132, miR-212, and miR-224 were increased (P<0.05) in L follicles; this was associated with reduced expression of the putative miRNA targets,PTEN,RASA1, andSMAD4. These novel results may indicate a physiological involvement of miR-21, miR-145, miR-224, miR-378, miR-132, and miR-212 in the regulation of cell survival, steroidogenesis, and differentiation during follicle selection and ovulation in the monovular ovary.

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Ligands, receptors and transcription factors that mediate inter-cellular and intra-cellular communication during ovarian follicle development

10.1101/594234 ◽

2019 ◽

Author(s):

Beatriz Peñalver Bernabé ◽

Teresa Woodruff ◽

Linda J Broadbelt ◽

Lonnie D Shea

Keyword(s):

Transcription Factors ◽

Ovarian Follicle ◽

Somatic Cells ◽

Follicle Development ◽

Paracrine Signaling ◽

Oocyte Growth ◽

Ovarian Follicle Development ◽

Ovarian Folliculogenesis ◽

Follicle Maturation

SUMMARYReliably producing a competent oocyte entails a deeper comprehension of ovarian follicle maturation, a very complex process that includes meiotic maturation of the female gamete, the oocyte, together with the mitotic divisions of the hormone-producing somatic cells. In this report, we investigate mice ovarian folliculogenesis in vivo using publically available time-series microarrays from primordial to antral stage follicles. Manually curated protein interaction networks were employed to identify autocrine and paracrine signaling between the oocyte and the somatic cells (granulosa and theca cells) and the oocyte and cumulus and mural cells at multiple stages of follicle development. We established protein binding interactions between expressed genes that encoded secreted factors and expressed genes that encoded cellular receptors. Some of computationally identified signaling interactions are well established, such as the paracrine signaling from the oocyte to the somatic cells through the secreted oocyte growth factor Gdf9; while others are novel connections in term of ovarian folliculogenesis, such as the possible paracrine connection from somatic secreted factor Ntn3 to the oocyte receptor Neo1. Additionally, we identify several of the likely transcription factors that might control the dynamic transcriptome during ovarian follicle development, noting that the YAP/TAP signaling is very active in vivo. This novel dynamic model of signaling and regulation can be employed to generate testable hypotheses regarding follicle development, guide the improvement of culture media to enhance in vitro ovarian follicle maturation and possibly as novel therapeutic targets for reproductive diseases.

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Ovarian follicle development in the laying hen is accompanied by divergent changes in inhibin A, inhibin B, activin A and follistatin production in granulosa and theca layers

Journal of Endocrinology ◽

10.1677/joe.0.1770045 ◽

2003 ◽

Vol 177 (1) ◽

pp. 45-55 ◽

Cited By ~ 46

Author(s):

TM Lovell ◽

RT Gladwell ◽

NP Groome ◽

PG Knight

Keyword(s):

Functional Role ◽

Ovarian Follicle ◽

Fold Increase ◽

Activin A ◽

Inhibin B ◽

Follicle Development ◽

Inhibin A ◽

Ovarian Follicle Development ◽

Tissue Extracts

To study the potential involvement of inhibin A (inhA), inhibin B (inhB), activin A (actA) and follistatin (FS) in the recruitment of follicles into the preovulatory hierarchy, growing follicles (ranging from 1 mm to the largest designated F1) and the three most recent postovulatory follicles (POFs) were recovered from laying hens (n=11). With the exception of <4 mm follicles and POFs, follicle walls were dissected into separate granulosa (G) and theca (T) layers before extraction. Contents of inhA, inhB, actA and FS in tissue extracts were assayed using specific two-site ELISAs and results are expressed per mg DNA. InhB content of both G and T followed a similar developmental pattern, although the content was >4-fold higher in G than in T at all stages. InhB content was very low in follicles <4 mm but increased ~50-fold (P<0.0001) to peak in 7-9 mm follicles, before falling steadily as follicles entered and moved up the follicular hierarchy (40-fold; 8 mm vs F2). In stark contrast, inhA remained very low in prehierarchical follicles (< or =9 mm) but then increased progressively as follicles moved up the preovulatory hierarchy to peak in F1 (approximately 100-fold increase; P<0.0001); In F1 >97% of inhA was confined to the G layer whereas in 5-9 mm follicles inhA was only detected in the T layer. Both inhA and inhB contents of POFs were significantly reduced compared with F1. Follicular actA was mainly confined to the T layer although detectable levels were present in G from 9 mm; actA was low between 1 and 9 mm but increased sharply as follicles entered the preovulatory hierarchy (approximately 6-fold higher in F4; P<0.0001); levels then fell approximately 2-fold as the follicle progressed to F1. Like actA, FS predominated in the T although significant amounts were also present in the G of prehierarchical follicles (4-9 mm), in contrast to actA, which was absent from the G. The FS content of T rose approximately 3-fold from 6 mm to a plateau which was sustained until F1. In contrast, the FS content of G was greatest in prehierarchical follicles and fell approximately 4-fold in F4-F1 follicles. ActA and FS contents of POFs were reduced compared with F1. In vitro studies on follicle wall explants confirmed the striking divergence in the secretion of inhA and inhB during follicle development. These findings of marked stage-dependent differences in the expression of inhA, inhB, actA and FS proteins imply a significant functional role for these peptides in the recruitment and ordered progression of follicles within the avian ovary.

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Initial and Cyclic Recruitment of Ovarian Follicles*

Endocrine Reviews ◽

10.1210/edrv.21.2.0394 ◽

2000 ◽

Vol 21 (2) ◽

pp. 200-214 ◽

Cited By ~ 34

Author(s):

Elizabeth A. McGee ◽

Aaron J. W. Hsueh

Keyword(s):

Ovarian Follicle ◽

Ovarian Follicles ◽

Follicle Development ◽

Ovarian Follicle Development ◽

Branching Points ◽

Reproductive Techniques ◽

Recruitment And Selection ◽

Cyclic Recruitment

Abstract Mammalian ovaries consist of follicles as basic functional units. The total number of ovarian follicles is determined early in life, and the depletion of this pool leads to reproductive senescence. Each follicle develops to either ovulate or, more likely, to undergo degeneration. The dynamics of ovarian follicle development have interested endocrinologists and developmental biologists for many years. With the advent of assisted reproductive techniques in humans, the possibility of regulating follicle development in vivo and in vitro has gained clinical relevance. In this review, we focus upon key branching points during the development of ovarian follicles as well as factors involved in determining the eventual destiny of individual follicles. We discuss inconsistencies in the literature regarding the definitions of follicle recruitment and selection and propose to name the two major steps of follicle development as initial and cyclic recruitment, respectively. Because some of these disparities have arisen due to differences in the animal systems studied, we also compare the development of the ovarian follicles of both humans and rats. We also review the status of knowledge of several puzzling clinical issues that may provide important clues toward unlocking the mechanisms of follicle development.

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