A mouse model reveals the events and underlying regulatory signals during the gonadotrophin-dependent phase of follicle development

ABSTRACT During folliculogenesis, the gonadotrophin (GTH)-dependent phase begins at the small antral follicle stage and ends with Graafian follicles. In this study, pregnant mare’s serum GTH was used to induce GTH-dependent folliculogenesis in mice, following which the developmental events that follicles undergo, as well as the underlying regulatory signals, were investigated at both the morphological and transcriptomic level. GTH-dependent folliculogenesis consisted of three phases: preparation, rapid growth and decelerated growth. In the preparation phase, comprising the first 12 h, granulosa cells completed the preparations for proliferation and differentiation, shifted energy metabolism to glycolysis, and reduced protein synthesis and processing. The rapid growth phase lasted from 12 to 24 h; in this phase, granulosa cells completed their proliferation, and follicles acquired the capacity for estradiol secretion and ovulation. Meanwhile, the decelerating growth phase occurred between 24 and 48 h of GTH-dependent folliculogenesis. In this phase, the proliferation and expansion of the follicular antrum were reduced, energy metabolism was shifted to oxidative phosphorylation, and cell migration and lipid metabolism were enhanced in preparation for luteinization. We also revealed the key signaling pathways that regulate GTH-dependent folliculogenesis and elucidated the activation sequence of these pathways. A comparison of our RNA-sequencing data with that reported for humans suggested that the mechanisms involved in mouse and human folliculogenesis are evolutionarily conserved. In this study, we draw a detailed atlas of GTH-dependent folliculogenesis, thereby laying the foundation for further investigation of the regulatory mechanisms underlying this process.

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Syndecan 1 represses cell growth and FSH responsiveness in human granulosa cells

Reproduction ◽

10.1530/rep-17-0074 ◽

2017 ◽

Vol 153 (6) ◽

pp. 797-808 ◽

Cited By ~ 1

Author(s):

Simon Colombe ◽

Laura Houllier ◽

Emmanuelle Fleurot ◽

Guénaëlle Levallet ◽

Annie Benhaïm ◽

...

Keyword(s):

Granulosa Cells ◽

Morphological Changes ◽

Heparan Sulphate ◽

Follicular Development ◽

Antral Follicle ◽

Gene Expressions ◽

Cytoskeletal Organization ◽

Cellular Processes ◽

Proliferation And Differentiation ◽

Small Antral Follicle

Albeit devoid of intrinsic catalytic activity, the transmembrane heparan sulphate proteoglycan syndecan 1 plays critical roles in cellular processes such as extracellular matrix crosstalk, cytoskeletal organization, cell spreading, proliferation and differentiation. During the ovarian cycle, the expression of syndecan 1 in granulosa cells shows cyclic variation suggesting that it might fulfil specific roles in follicle development. To investigate its physiological roles on granulosa cells, syndecan 1 was overexpressed in human granulosa cell line KGN which retains features of granulosa cells from small antral follicle such as estradiol (E2) synthesis and low expression of functional FSH receptor (FSHR). We demonstrated that overexpression of syndecan 1 in immature granulosa cells (KGN-SDC1) induces a profound alteration in their intrinsic characteristics including enhanced spreading and attachment, both associated with a reduced growth rate. Flow cytometry analysis revealed that syndecan 1 overexpression increases the percentage of KGN cells in quiescent phase. This partial cell cycle exit is concordant with downregulated levels of CCND1 and CDK4 and upregulated expression of CDK inhibitor CDKN1A. In parallel both unstimulated and FSH-induced E2 synthesis are reduced in KGN-SDC1 through both repression of CYP19A1 and FSHR mRNA associated with decreased levels of potential regulators NR5A1 and ESR2. Additionally, we provide evidence that transient cAMP accumulation reduction in cells overexpressing syndecan 1 is accompanied by an increase in cAMP-hydrolysing PDE activity. Our results demonstrated that syndecan 1 might regulate differentiation of granulosa cells and follicular development by means of various mechanisms involving morphological changes, control of signalling pathways and alterations in gene expressions. Free French abstract: A French translation of this abstract is freely available at http://www.reproduction-online.org/content/153/6/797/suppl/DC2

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The bimodular development of ovarian follicles in cyclic guinea pigs and differences between antral follicles developed at different phases of the cycle

Canadian Journal of Zoology ◽

10.1139/z90-150 ◽

1990 ◽

Vol 68 (5) ◽

pp. 1031-1036

Author(s):

G. S. Hamilton ◽

W. H. Tam

Keyword(s):

Growth Phase ◽

Rapid Growth ◽

Secretory Activity ◽

Maximum Size ◽

Antral Follicle ◽

Autoradiographic Study ◽

Thymidine Uptake ◽

Primordial Follicles ◽

Antral Follicles ◽

Second Wave

The results of a histological, [3H]thymidine uptake, and autoradiographic study of the cyclic guinea pig ovary suggest that there are two consecutive waves of antral follicle development within each estrous cycle, with the first wave extending from days 2 to 10 and the second wave from days 7 to 16 of the 16-day cycle. The bimodular development is apparently made possible by the continuous daily recruitment of growing follicles from the pool of dormant primordial follicles and by the occurrence of two occasions (days 1–3 and days 6–9) when gonadotropin secretory activity allows some of these follicles to progress into the antral phase of development. The antral follicles of the first wave attain their maximum size (0.5 mm3) on day 9. However, they have disappeared by day 12 and in their place, large atretic follicles and the smaller healthy antral follicles of the second wave have become the most prominent follicular features. On days 14 and 15, the antral follicles of the second wave have grown to 0.5 mm3 themselves, and within the next 24 h their volume increases rapidly by 150% to 1.23 mm3. Extrusion of first polar bodies, vaginal estrus, and ovulation then follow in quick succession. The results indicate that the follicles of the first wave become atretic before the final rapid growth phase and resumption of meiotic division. The absence of the rapid growth phase probably indicates that they have never reached final maturity, nor have they achieved the competence to ovulate in response to gonadotropin stimulation.

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Ultrastructure of the basal lamina of bovine ovarian follicles and its relationship to the membrana granulosa

Reproduction ◽

10.1530/reprod/118.2.221 ◽

2000 ◽

pp. 221-228 ◽

Cited By ~ 7

Author(s):

HF Irving-Rodgers ◽

RJ Rodgers

Keyword(s):

Basal Lamina ◽

Granulosa Cells ◽

Light And Electron Microscopy ◽

Single Layer ◽

Antral Follicle ◽

Basal Cells ◽

Preantral Follicles ◽

Antral Follicles ◽

Cellular Processes ◽

Innermost Layer

Different morphological phenotypes of follicular basal lamina and of membrana granulosa have been observed. Ten preantral follicles (< 0. 1 mm), and 17 healthy and six atretic antral follicles (0.5-12 mm in diameter) were processed for light and electron microscopy to investigate the relationship the between follicular basal lamina and membrana granulosa. Within each antral follicle, the shape of the basal cells of the membrana granulosa was uniform, and either rounded or columnar. There were equal proportions of follicles </= 4 mm in diameter with columnar basal cells and with rounded basal cells. Larger follicles had only rounded basal cells. Conventional basal laminae of a single layer adjacent to the basal granulosa cells were observed in healthy follicles at the preantral and antral stages. However, at the preantral stage, the conventional types of basal lamina were enlarged or even partially laminated. A second type of basal lamina, described as 'loopy', occurred in about half the preantral follicles and in half the antral follicles </= 4 mm diameter. 'Loopy' basal laminae were not observed in larger follicles. 'Loopy' basal laminae were composed of basal laminae aligning the basal surface of basal granulosa cells, but with additional layers or loops often branching from the innermost layer. Each loop was usually < 1 microm long and had vesicles (20-30 nm) attached to the inner aspect. Basal cellular processes were also common, and vesicles could be seen budding off from these processes. In antral follicles, conventional basal laminae occurred in follicles with rounded basal granulosa cells. Other follicles with columnar cells, and atretic follicles, had the 'loopy' basal lamina phenotype. Thus, follicles have different basal laminae that relate to the morphology of the membrana granulosa.

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miR-21-5p Regulates the Proliferation and Differentiation of Skeletal Muscle Satellite Cells by Targeting KLF3 in Chicken

Genes ◽

10.3390/genes12060814 ◽

2021 ◽

Vol 12 (6) ◽

pp. 814

Author(s):

Donghao Zhang ◽

Jinshan Ran ◽

Jingjing Li ◽

Chunlin Yu ◽

Zhifu Cui ◽

...

Keyword(s):

Skeletal Muscle ◽

Satellite Cells ◽

Muscle Development ◽

Target Genes ◽

Cell Number ◽

Sequencing Data ◽

Proliferation Markers ◽

Muscle Satellite Cells ◽

Skeletal Muscle Satellite Cells ◽

Proliferation And Differentiation

The proliferation and differentiation of skeletal muscle satellite cells (SMSCs) play an important role in the development of skeletal muscle. Our previous sequencing data showed that miR-21-5p is one of the most abundant miRNAs in chicken skeletal muscle. Therefore, in this study, the spatiotemporal expression of miR-21-5p and its effects on skeletal muscle development of chickens were explored using in vitro cultured SMSCs as a model. The results in this study showed that miR-21-5p was highly expressed in the skeletal muscle of chickens. The overexpression of miR-21-5p promoted the proliferation of SMSCs as evidenced by increased cell viability, increased cell number in the proliferative phase, and increased mRNA and protein expression of proliferation markers including PCNA, CDK2, and CCND1. Moreover, it was revealed that miR-21-5p promotes the formation of myotubes by modulating the expression of myogenic markers including MyoG, MyoD, and MyHC, whereas knockdown of miR-21-5p showed the opposite result. Gene prediction and dual fluorescence analysis confirmed that KLF3 was one of the direct target genes of miR-21-5p. We confirmed that, contrary to the function of miR-21-5p, KLF3 plays a negative role in the proliferation and differentiation of SMSCs. Si-KLF3 promotes cell number and proliferation activity, as well as the cell differentiation processes. Our results demonstrated that miR-21-5p promotes the proliferation and differentiation of SMSCs by targeting KLF3. Collectively, the results obtained in this study laid a foundation for exploring the mechanism through which miR-21-5p regulates SMSCs.

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CircRILPL1 promotes muscle proliferation and differentiation via binding miR-145 to activate IGF1R/PI3K/AKT pathway

Cell Death and Disease ◽

10.1038/s41419-021-03419-y ◽

2021 ◽

Vol 12 (2) ◽

Author(s):

Xuemei Shen ◽

Jia Tang ◽

Rui Jiang ◽

Xiaogang Wang ◽

Zhaoxin Yang ◽

...

Keyword(s):

Signaling Pathway ◽

Muscle Development ◽

Inhibitory Effect ◽

Akt Signaling ◽

Luciferase Assay ◽

Circular Rnas ◽

Akt Signaling Pathway ◽

Sequencing Data ◽

Proliferation And Differentiation ◽

Myoblast Proliferation

AbstractMany novel non-coding RNAs, such as microRNAs (miRNAs) and circular RNAs (circRNAs), are involved in various physiological and pathological processes. The PI3K/AKT signaling pathway is important for its role in regulating skeletal muscle development. In this study, molecular and biochemical assays were used to confirm the role of miRNA-145 (miR-145) in myoblast proliferation and apoptosis. Based on sequencing data and bioinformatics analysis, we identified a new circRILPL1, which acts as a sponge for miR-145. The interactions between circRILPL1 and miR-145 were examined by bioinformatics, a luciferase assay, and RNA immunoprecipitation. Mechanistically, knockdown or exogenous expression of circRILPL1 in the primary myoblasts was performed to prove the functional significance of circRILPL1. We investigated the inhibitory effect of miR-145 on myoblast proliferation by targeting IGF1R to regulate the PI3K/AKT signaling pathway. A novel circRILPL1 was identified that could sponge miR-145 and is related to AKT activation. In addition, circRILPL1 was positively correlated with muscle proliferation and differentiation in vitro and could inhibit cell apoptosis. The newly identified circRILPL1 functions as a miR-145 sponge to regulate the IGF1R gene and rescue the inhibitory effect of miR-145 on the PI3K/AKT signaling pathway, thereby promoting myoblast growth.

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The role of IGFs in the regulation of ovarian follicular growth in the brushtail possum (Trichosurus vulpecula)

Reproduction ◽

10.1530/rep-10-0142 ◽

2010 ◽

Vol 140 (2) ◽

pp. 295-303 ◽

Cited By ~ 8

Author(s):

Jennifer L Juengel ◽

Lisa J Haydon ◽

Brigitta Mester ◽

Brian P Thomson ◽

Michael Beaumont ◽

...

Keyword(s):

Granulosa Cell ◽

Granulosa Cells ◽

Cell Function ◽

Antral Follicle ◽

Brushtail Possum ◽

Follicular Growth ◽

Theca Cells ◽

Ovarian Follicular Growth

IGFs are known to be key regulators of ovarian follicular growth in eutherian mammals, but little is known regarding their role in marsupials. To better understand the potential role of IGFs in the regulation of follicular growth in marsupials, expression of mRNAs encoding IGF1, IGF2, IGF1R, IGF-binding protein 2 (IGFBP2), IGFBP4 and IGFBP5 was localized by in situ hybridization in developing ovarian follicles of the brushtail possum. In addition, the effects of IGF1 and IGF2 on granulosa cell function were tested in vitro. Both granulosa and theca cells synthesize IGF mRNAs, with the theca expressing IGF1 mRNA and granulosa cell expressing IGF2 mRNA. Oocytes and granulosa cells express IGF1R. Granulosa and theca cells expressed IGFBP mRNAs, although the pattern of expression differed between the BPs. IGFBP5 mRNA was differentially expressed as the follicles developed with granulosa cells of antral follicles no longer expressing IGFBP5 mRNA, suggesting an increased IGF bioavailability in the antral follicle. The IGFBP protease, PAPPA mRNA, was also expressed in granulosa cells of growing follicles. Both IGF1 and IGF2 stimulated thymidine incorporation but had no effect on progesterone production. Thus, IGF may be an important regulator of ovarian follicular development in marsupials as has been shown in eutherian mammals.

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Rapid Growth Phase of Ovum in the Guinea Fowl.

Japanese poultry science ◽

10.2141/jpsa.33.300 ◽

1996 ◽

Vol 33 (5) ◽

pp. 300-304

Author(s):

Hiroshi OGAWA ◽

Takehito KUWAYAMA ◽

Katuhide TANAKA

Keyword(s):

Growth Phase ◽

Rapid Growth ◽

Guinea Fowl

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Coated Vesicle-Mediated Transport and Deposition of Vitellogenic Ferritin in the Rapid Growth Phase of Snail Oocytes

Journal of Cell Science ◽

10.1242/jcs.53.1.173 ◽

1982 ◽

Vol 53 (1) ◽

pp. 173-191 ◽

Cited By ~ 1

Author(s):

W. BOTTKE ◽

I. SINHA ◽

I. KEIL

Keyword(s):

Growth Phase ◽

Rapid Growth ◽

Lymnaea Stagnalis ◽

Follicle Cells ◽

Coated Vesicle ◽

Secretory Cells ◽

Basal Region ◽

Coated Pits ◽

Iron Storage ◽

Basement Lamina

The main yolk component in oocytes of the pulmonate freshwater snails Planorbarius corneus L. and Lymnaea stagnalis L. consists of the iron storage protein ferritin and iron-free apoferritin. Both compounds are deposited in the yolk in the form of large paracrystalloids, tubular structures and randomly dispersed particles. In addition, the plasm contains lysosome-like inclusions with depositions of haemosiderin. Haemosiderin is interpreted as the product of proteolytic degradation of ferritin. During the rapid growth phase of the oocytes vitellogenic ferritin is transported across the basement lamina and taken up by adsorptive endocytosis via coated pits and vesicles. Formation of yolk bodies occurs by fusion of ferritin-containing vacuoles and empty vesicles that are probably derived from the Golgi apparatus. Uptake of ferritin is restricted to the basal region of the oocyte. No involvement of the follicle cells in synthesis and deposition of ferritin could be detected. Secretory cells of the midgut gland are the most likely site of synthesis of vitellogenic ferritin. Under conditions of iron overload large masses of ferritin are encountered in the basement lamina of the oocytes. However, no significant increase in the uptake of ferritin could be observed. With the use of a tannic acid-glutaraldehyde fixation procedure a hitherto unobserved filamentous or rod-like material was detected inside the lamina and in coated pits. This material is probably also taken up by the oocytes and integrated into yolk platelets. Though ferritin is a rather unusual vitellogenic protein, the mode of its uptake and deposition in the oocyte plasm is highly reminiscent of that of typical hormone-induced vitellogenins in other animal groups.

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