Timely expression and activation of YAP1 in granulosa cells is essential for ovarian follicle development. Lv X et al. (2019) Although the role of the Hippo signaling pathway in development and tumorigenesis has been extensively studied in multiple organs, its role in ovarian follicle development remains largely unknown. Here, we report that Yes-Associated Protein 1 (YAP1), the major effector of Hippo signaling, is spatiotemporally expressed in ovarian granulosa cells and plays a critical role in the regulation of follicle development. We found that the active form of YAP1 (nuclear YAP1) was predominantly expressed in proliferative granulosa cells, whereas the inactive form of YAP1 (cytoplasmic YAP1) was mainly detected in luteal cells (terminally differentiated granulosa cells). Pharmacological inhibition of YAP1 activity disrupted mouse ovarian follicle development in vitro and in vivo. Foxl2 promoter-driven knockout of Yap1 in ovarian granulosa cells resulted in increased apoptosis of granulosa cells, decreased number of corpora lutea, reduced ovarian size, and subfertility in transgenic mice. However, Cyp19a1 promoter-driven knockout of Yap1 in differentiated granulosa cells of preovulatory follicles and luteal cells of corpora lutea had no effect on ovarian morphology and fertility. Mechanistic studies demonstrated that YAP1 interacted with epidermal growth factor receptor and TGF-β signaling pathways to regulate granulosa cell proliferation, differentiation, and survival. Results from this study identify YAP1 as a critical regulator of granulosa cell proliferation and differentiation. Balanced expression and activation of YAP1 is essential for follicle development and successful reproduction. YAP1 is a promising target for treatment of subfertility associated with abnormal granulosa cell function.-Lv, X., He, C., Huang, C., Wang, H., Hua, G., Wang, Z., Zhou, J., Chen, X., Ma, B., Timm, B. K., Maclin, V., Dong, J., Rueda, B. R., Davis, J. S., Wang, C. Timely expression and activation of YAP1 in granulosa cells is essential for ovarian follicle development. HGEGF was found to be DOWNSTREAM OF YAP IN STIMULATING GRANULOSA CELL PROLIFERATION.//////////////////
Mouse cells are naturally resistant to diphtheria toxin because they lack functional cell surface receptors for the toxin.
Naglich et al. (1992) isolated a monkey cDNA encoding the diphtheria toxin sensitivity determinant by expression cloning
in mouse L-M cells. Unlike wildtype L-M cells, transfected mouse cells were extremely toxin sensitive and specifically
bound radioiodinated diphtheria toxin. Intoxication of the transfected cells required receptor-mediated endocytosis of the
bound toxin. The cDNA was predicted to encode an integral membrane protein that is identical to the precursor of a
heparin-binding EGF-like growth factor . Thus the DT sensitivity protein is a growth
factor precursor that the toxin exploits as a receptor.
Bochen Pan, et al 2002 reported that the soluble and membrane-anchored forms of heparin-binding epidermal growth factor-like growth
factor appear to play opposing roles in the survival and
apoptosis of human luteinized granulosa cells.
Epidermal Growth Factor Receptor (EGFR) Ligands in the Chicken Ovary: I) Evidence for Heparin-binding Epidermal Growth Factor-like Growth Factor (HB-EGF) as a Potential Oocyte-derived Signal to Control Granulosa Cell Proliferation and HB-EGF and Kit Ligand (KL) Expression. Wang Y et al. There is increasing evidence that EGFR ligand and Kit ligand (KL) play critical roles in controlling follicular development in mammals. As little is known about their expressions in the ovary of nonmammalian vertebrate, our study aimed to examine the expression, hormonal regulation, and interaction of HB-EGF and KL in the chicken ovary. Using semi-quantitative RT-PCR, we demonstrated that ovarian HB-EGF expression increased dramatically with the posthatching ovarian growth. In line with this finding, HB-EGF was shown to be produced primarily by the growing oocytes and capable of stimulating the proliferation of granulosa cells in prehierarchal (3mm) and preovulatory follicles (F5 and F1). Although HB-EGF expression is mainly restricted to the oocytes, its expression in cultured granulosa cells could be transiently yet strongly induced by HB-EGF and other EGFR ligands including EGF and TGF-alpha. And the inducing effect of HB-EGF was completely abolished by AG1478 (10 microM) or PD98059 (100 microM), indicating that the action of HB-EGF is mediated by EGFR and intracellular MAPK/ERK signaling pathway. Unlike mammals, only KL-1, not the other three isoforms identified (KL-2, KL-3 and KL-4), was detected to be predominantly expressed in the chicken ovary. Interestingly, KL expression in undifferentiated and differentiated granulosa cells could be transiently downregulated by HB-EGF, implying an intrafollicular communication between growing oocyte and surrounding granulosa cells through the interplay of EGFR ligand and KL. Collectively, our data suggest that HB-EGF is likely a paracrine signal from the oocyte to regulate granulosa cell proliferation and HB-EGF and KL expression during ovarian follicular development.
This study aims to investigate the expression of heparin-binding epidermal growth factor-like growth factor (HB-EGF) and
its role in regulating apoptosis of human luteinized granulosa cells (LGC). By using RT-PCR and immunocytochemistry, the
expression of HB-EGF and the EGF receptor family was demonstrated. HER4, one of the two cognate receptors for
HB-EGF, was found translocated into the nucleus. HB-EGF exists in two forms, the precursor membrane-anchored form
and the mature secreted form. Addition of recombinant HB-EGF, which acts as the secreted form, into the cell culture
inhibited apoptosis and appeared to stimulate mitosis, indicating that the secreted form is potentially an anti-apoptotic
factor and a mitogen for LGC. In contrast, CRM197, a specific inhibitor for the interaction between HB-EGF and the EGF
receptor, inhibited rather than enhanced apoptosis, suggesting that the membrane-anchored form constitutively functions as a
pro-apoptotic factor for LGC. Furthermore, the finding that apoptosis inhibition by CRM197 in the aggregate cells was
much more pronounced than in the single cells indicates that pro-apoptotic activity was carried out in a juxtacrine fashion,
as would be expected for the membrane-anchored form of HB-EGF. These data suggest that HB-EGF may be a unique
regulator of LGC apoptosis, with two functionally opposing products arising from the same gene.
Gene whose expression is detected by cDNA array hybridization: stress response, cell/cell communication. Also, relative transcript level reproducibly increases during IVM Rozenn Dalbi?Tran and Pascal Mermilloda
Expression regulated by
Comment
Ovarian localization
Granulosa, Luteal cells
Comment
Gene expression and immunolocalization of heparin-binding epidermal growth factor-like growth factor and human epidermal growth factor receptors in human corpus luteumAkayama Y, et al .
BACKGROUND: The objective of this study was to elucidate gene expression and immunolocalization of heparinbinding epidermal growth factor-like growth factor (HB-EGF) and human epidermal growth factor receptor (HER) family in the human ovary during luteal growth and regression. METHODS: Ovaries obtained from pre-menopausal women were used for immunohistochemistry and semiquantitative RT-PCR analysis. RESULTS: Immunoreactive HB-EGF was not detected in follicles or oocyte, while HB-EGF became apparent in granulosa luteal cells in the early luteal phase, and most abundant in the mid-luteal phase, but less abundant in the late luteal phase. Immunostaining for HER1 was very weak in granulosa luteal cells in the early and mid-luteal phases, and was not detected in the late luteal phase. Immunoreactive HER4 was abundant in the early luteal phase and became less abundant in the mid-luteal phase, whereas it was negative in the late luteal phase. Semiquantitative RT-PCR analysis revealed that HB-EGF and HER1 mRNA levels were high in the mid-luteal phase, whereas HER4 mRNA expression was high in the early luteal phase. CONCLUSIONS: HB-EGF may play a vital role in regulating luteal growth in a juxtacrine manner and through activating HER4 signalling.
Follicle stages
Preovulatory, Corpus luteum
Comment
Differential expression of heparin-binding epidermal growth factor-like growth factor in the rat ovary.
Pan B, et al investigated the expression of heparin-binding epidermal growth factor-like growth factor (HB-EGF) and its receptors in the rat ovary to define the role of HB-EGF in the ovarian function. The expression pattern of HB-EGF mRNA and protein were studied by semi-quantitative RT-PCR and immuno-histochemistry using an antibody that was specifically stained for the precursor form of HB-EGF in naturally cycling rats and immature pseudo-pregnant rat models. The immuno-histochemical study showed that in naturally cycling rats, HB-EGF was expressed in most granulosa cells of early follicles and all the developing follicles but not in preovulatory follicles. This was supported by the semi-quantitative RT-PCR results in that the lowest level of HB-EGF mRNA during the estrous cycle was found in the evening of proestrous when the HB-EGF negative preovulatory follicles were most prominent. The results suggest that HB-EGF might be a mitogen for granulosa cells and down regulation of its expression may be necessary for the final maturation of follicles. In corpora lutea, luteal cells of older generation stained stronger than those of younger generation. Moreover, luteal cells of late luteal phase stained stronger than those of the mid and early luteal phases in the immature pseudo-pregnant rat models, indicating that the precursor form may be associated with death of luteal cells. Finally, of the two cognate receptors for HB-EGF, erbB1 was expressed in the rat ovary, but erbB4 was specifically not expressed in this organ. The spatial and temporal pattern of HB-EGF expression suggest that HB-EGF may an important local regulator of ovarian function and structure.