scholarly journals Role of FSH and epidermal growth factor (EGF) in the initiation of steroidogenesis in granulosa cells associated with follicular selection in chicken ovaries

Reproduction ◽  
2003 ◽  
pp. 683-691 ◽  
Author(s):  
AG Hernandez ◽  
JM Bahr

In chicken ovaries, one small yellow follicle (SYF) is selected daily from a pool of follicles of similar size and becomes a preovulatory follicle. FSH induces follicular growth and steroidogenesis. Epidermal growth factor (EGF), an intraovarian hormone, suppresses granulosa cell differentiation. This study demonstrates that recruitment of SYFs into the hierarchy of preovulatory follicles is associated with a change in steroidogenic activity in granulosa cells regulated, at least in part, by FSH and EGF. Abundance of P450 side-chain cleavage (P450scc) mRNA was higher in the smallest preovulatory follicle (F6) compared with SYF, whereas FSH and EGF receptor (FSHr and EGFr, respectively) mRNA abundance was similar. FSH increased P450scc mRNA abundance and progesterone secretion and decreased FSHr mRNA in cultured granulosa cells, whereas EGF attenuated or suppressed P450scc mRNA and decreased FSHr mRNA abundance. None of the hormones influenced EGFr mRNA abundance. When used in combination, EGF attenuated or suppressed the stimulatory effect of FSH on the expression of P450scc mRNA and production of progesterone in a dose-dependent manner. The results indicate that (1) selection is associated with an increase in P450scc mRNA; (2) FSH stimulates expression of P450scc mRNA and progesterone secretion in granulosa cells of SYF; and (3) induction of P450scc mRNA and progesterone secretion by FSH is attenuated or blocked by EGF.

2009 ◽  
Vol 21 (9) ◽  
pp. 53
Author(s):  
M. Sasseville ◽  
L. J. Ritter ◽  
T. Nguyen ◽  
D. G. Mottershead ◽  
D. L. Russell ◽  
...  

Oocyte-secreted growth differentiation factor 9 (GDF9) plays a critical role throughout folliculogenesis. It has been shown to control many functions of granulosa cells, including gene expression, steroidogenesis and proliferation. This study investigates the cellular requirements that allow GDF9 to act on granulosa cells. Our results showed that GDF9 (20 ng/ml)-stimulated mouse granulosa cells 3H-thymidine incorporation was inhibited by a type 1 receptor Alk4/5/7 inhibitor (SB431542, 5 μM), by an epidermal growth factor (EGF) receptor inhibitor (AG1478, 5μM) and a MEK1 inhibitor (U0126, 10 μM). Interestingly, activin A- and TGFβ-stimulated 3H-thymidine incorporation shared similar inhibitor sensitivity. Moreover, when denuded oocytes were used as the mitogenic agent, SB431542, AG1478 and U0126 all prevented the increase in 3H-thymidine incorporation. Oocyte-stimulated 3H-thymidine incorporation in secondary follicles and cumulus-oocyte complexes were also sensitive to Alk4/5/7, EGF receptor and MEK1 inhibition. Basal and EGF-stimulated levels of phopho-MAPK3/1 were inhibited by using the EGF receptor inhibitor, but were not affected by inhibition of Alk4/5/7 or by adding GDF9 in granulosa cells. Using granulosa cells transfected with a SMAD3-luciferase reporter construct, GDF9-stimulated SMAD3 response could be inhibited by Alk4/5/7, EGFR and MEK1 inhibitors. Genes involved in cumulus cells expansion (Ptx3 and Has2) were upregulated in granulosa cells by co-culturing with denuded oocytes and that upregulation was inhibited by Alk4/5/7 as well as by EGF receptor inhibition. These results suggest that TGFβ superfamily members signalling through Smad2/3 share a common requirement of EGF receptor-dependant phospho-MAPK3/1 throughout folliculogenesis. These results strongly suggest that, apart from its role in the transmission of the ovulatory LH signal within the ovarian follicle, EGF receptor pathway might serve as modulators of GDF9 action on granulosa cells. Hence the interaction between endocrine and oocyte signalling may be mediated at the level of MAPK and Smad2/3 cross-talk in granulosa cells.


1986 ◽  
Vol 239 (3) ◽  
pp. 691-697 ◽  
Author(s):  
N Reiss ◽  
H Kanety ◽  
J Schlessinger

Several enzymes of the glycolytic pathway are phosphorylated in vitro and in vivo by retroviral transforming protein kinases. These substrates include the enzymes phosphoglycerate mutase (PGM), enolase and lactate dehydrogenase (LDH). Here we show that purified EGF (epidermal growth factor)-receptor kinase phosphorylates the enzymes PGM and enolase and also the key regulatory enzymes of the glycolytic pathway, phosphofructokinase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), in an EGF-dependent manner. Stoichiometry of phosphate incorporation into GAPDH (calculated from native Mr) is the highest, reaching approximately 1. LDH and other enzymes of the glycolytic pathway are not phosphorylated by the purified EGF-receptor kinase. These enzymes are phosphorylated under native conditions, and the Km values of EGF-receptor kinase for their phosphorylation are close to the physiological concentrations of these enzymes in the cell. EGF stimulates the reaction by 2-5-fold by increasing the Vmax. without affecting the Km of this process. Phosphorylation is rapid at 22 degrees C and at higher temperatures. However, unlike the self-phosphorylation of EGF-receptor, which occurs at 4 degrees C, the glycolytic enzymes are poorly phosphorylated at this temperature. Some enzymes, in particular enolase, increase the receptor Km for ATP in the autophosphorylation process and thus may act as competitive inhibitors of EGF-receptor self-phosphorylation. On the basis of the Km values of EGF receptor for the substrate enzymes and for ATP in the phosphorylation reaction, these enzymes may also be substrates in vivo for the EGF-receptor kinase.


2003 ◽  
Vol 285 (2) ◽  
pp. R455-R462 ◽  
Author(s):  
Miguel Pareja ◽  
Olga Sánchez ◽  
Jordi Lorita ◽  
Maria Soley ◽  
Ignasi Ramírez

Acute, high-intensity stress induces necrotic lesions in the heart. We found that restraint-and-cold (4°C) exposure (RCE) raises plasma lactate dehydrogenase (LDH), creatine kinase (CK), and transaminase activity in a time-dependent manner, with a peak value 7 h after stimulus cessation. At 24 h, signs of necrotic lesions were observed in paraffin sections stained with hematoxylineosin: focal accumulation of mononuclear cells in subendocardial areas of the left ventricle wall and focal hemorrhage in papillary muscles. In contrast, intermale fighting (IF) did not increase plasma CK activity, although LDH and transaminase activities did increase. In IF, no histological evidence of heart injury was observed. Because IF, but not RCE, increased plasma epidermal growth factor (EGF) concentration by ∼1,000-fold, we hypothesized that EGF receptor (ErbB1) activation may protect the heart against stress-induced injury. To examine this hypothesis, we injected the ErbB1 tyrosine kinase inhibitor tyrphostin AG-1478 (25 mg/kg ip) immediately before mice were exposed to IF. After 3 h, plasma activities of LDH-1 and CK increased. Plasma enzyme activities were as low in control mice (injected with vehicle alone) as in nonfighting mice. In the last experiment, we injected EGF (0.25 mg/kg ip) 20 min before exposing mice to RCE. After 7 h, plasma LDH-1 and CK activities were significantly lower in these animals than in mice injected with vehicle. The effect required ErbB1 activation, because simultaneous administration of AG-1478 completely abolished the effect of exogenous EGF. We conclude that activated ErbB1, by endogenous or exogenous ligands, may protect the heart against stress-induced injury.


Endocrinology ◽  
2007 ◽  
Vol 148 (7) ◽  
pp. 3426-3440 ◽  
Author(s):  
Yajun Wang ◽  
Juan Li ◽  
Crystal Ying Wang ◽  
Amy Ho Yan Kwok ◽  
Frederick C. Leung

There is increasing evidence that epidermal growth factor (EGF) receptor (EGFR) ligand and Kit ligand (KL) play critical roles in controlling follicular development in mammals. Because 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 semiquantitative 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 (3 mm) 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-α. And the inducing effect of HB-EGF was completely abolished by AG1478 (10 μm) or PD98059 (100 μm), 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, -3, and -4), was detected to be predominantly expressed in the chicken ovary. Interestingly, KL expression in undifferentiated and differentiated granulosa cells could be transiently down-regulated 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.


2001 ◽  
Vol 154 (2) ◽  
pp. 459-468 ◽  
Author(s):  
C. Scott Swindle ◽  
Kien T. Tran ◽  
Terry D. Johnson ◽  
Pallab Banerjee ◽  
Anne M. Mayes ◽  
...  

Signaling through growth factor receptors controls such diverse cell functions as proliferation, migration, and differentiation. A critical question has been how the activation of these receptors is regulated. Most, if not all, of the known ligands for these receptors are soluble factors. However, as matrix components are highly tissue-specific and change during development and pathology, it has been suggested that select growth factor receptors might be stimulated by binding to matrix components. Herein, we describe a new class of ligand for the epidermal growth factor (EGF) receptor (EGFR) found within the EGF-like repeats of tenascin-C, an antiadhesive matrix component present during organogenesis, development, and wound repair. Select EGF-like repeats of tenascin-C elicited mitogenesis and EGFR autophosphorylation in an EGFR-dependent manner. Micromolar concentrations of EGF-like repeats induced EGFR autophosphorylation and activated extracellular signal–regulated, mitogen-activated protein kinase to levels comparable to those induced by subsaturating levels of known EGFR ligands. EGFR-dependent adhesion was noted when the ligands were tethered to inert beads, simulating the physiologically relevant presentation of tenascin-C as hexabrachion, and suggesting an increase in avidity similar to that seen for integrin ligands upon surface binding. Specific binding to EGFR was further established by immunofluorescence detection of EGF-like repeats bound to cells and cross-linking of EGFR with the repeats. Both of these interactions were abolished upon competition by EGF and enhanced by dimerization of the EGF-like repeat. Such low affinity behavior would be expected for a matrix-“tethered” ligand; i.e., a ligand which acts from the matrix, presented continuously to cell surface EGF receptors, because it can neither diffuse away nor be internalized and degraded. These data identify a new class of “insoluble” growth factor ligands and a novel mode of activation for growth factor receptors.


2006 ◽  
Vol 20 (6) ◽  
pp. 1352-1365 ◽  
Author(s):  
Masayuki Shimada ◽  
Inmaculada Hernandez-Gonzalez ◽  
Ignacio Gonzalez-Robayna ◽  
JoAnne S. Richards

Abstract The molecular bridges that link the LH surge with functional changes in cumulus cells that possess few LH receptors are being unraveled. Herein we document that epidermal growth factor (EGF)-like factors amphiregulin (Areg), epiregulin (Ereg), and betacellulin (Btc) are induced in cumulus oocyte complexes (COCs) by autocrine and paracrine mechanisms that involve the actions of prostaglandins (PGs) and progesterone receptor (PGR). Areg and Ereg mRNA and protein levels were reduced significantly in COCs and ovaries collected from prostaglandin synthase 2 (Ptgs2) null mice and Pgr null (PRKO) mice at 4 h and 8 h after human chorionic gonadotropin, respectively. In cultured COCs, FSH/forskolin induced Areg mRNA within 0.5 h that peaked at 4 h, a process blocked by inhibitors of p38MAPK (SB203580), MAPK kinase (MEK) 1 (PD98059), and PTGS2 (NS398) but not protein kinase A (PKA) (KT5720). Conversely, AREG but not FSH induced Ptsg2 mRNA at 0.5 h with peak expression of Ptgs2 and Areg mRNAs at 4 h, processes blocked by the EGF receptor tyrosine kinase inhibitor AG1478 (AG), PD98059, and NS398. PGE2 reversed the inhibitory effects of AG on AREG-induced expression of Areg but not Ptgs2, placing Ptgs2 downstream of EGF-R signaling. Phorbol 12-myristate 13-acetate (PMA) and adenovirally expressed PGRA synergistically induced Areg mRNA in granulosa cells. In COCs, AREG not only induced genes that impact matrix formation but also genes involved in steroidogenesis (StAR, Cyp11a1) and immune cell-like functions (Pdcd1, Runx1, Cd52). Collectively, FSH-mediated induction of Areg mRNA via p38MAPK precedes AREG induction of Ptgs2 mRNA via ERK1/2. PGs acting via PTGER2 in cumulus cells provide a secondary, autocrine pathway to regulate expression of Areg in COCs showing critical functional links between G protein-coupled receptor and growth factor receptor pathways in ovulating follicles.


1992 ◽  
Vol 9 (2) ◽  
pp. 147-156 ◽  
Author(s):  
U. Michel ◽  
J. W. McMaster ◽  
J. K. Findlay

ABSTRACT The regulation of steady-state follistatin mRNA levels by different pituitary hormones and peptide factors was examined in granulosa cell cultures derived from diethylstilboestrol-treated immature rats. Cytosolic RNA from cell cultures was prepared by lysis and equal amounts of RNA from all samples were analysed with a solution—hybridization assay using a 32P-labelled antisense probe corresponding to a part of exon 5 together with a part of the 5′ end of exon 6 of the rat follistatin gene. In addition, a specific 35S-labelled probe for cyclophilin was used as an internal standard. The results show that 5 μg FSH/1 for 24 to 72 h stimulated steady-state follistatin mRNA levels, reaching levels 18·5-fold higher than controls. LH (0·2-100 μg/l) had only minor effects on follistatin mRNA levels in FSH-primed granulosa cells and prolactin, GH and IGF-I did not show any significant effects. Activin raised basal as well as FSH-stimulated steady-state follistatin mRNA levels up to ten- and twofold above controls respectively, whereas epidermal growth factor was found to inhibit FSH-stimulated follistatin mRNA levels in a dose-dependent manner. It is concluded that follistatin mRNA levels in granulosa cells are regulated by FSH rather than LH, and that the stimulation by FSH can be inhibited by epidermal growth factor but enhanced by activin. Activin alone was also capable of stimulating follistatin mRNA.


1995 ◽  
Vol 19 (6) ◽  
pp. 1382-1388 ◽  
Author(s):  
Pamela P. McKenzie ◽  
Joseph D. McClaran ◽  
Michael R. Caudle ◽  
Aisaku Fukuda ◽  
Jay Wimalasena

2006 ◽  
Vol 26 (14) ◽  
pp. 5481-5496 ◽  
Author(s):  
Hanshuang Shao ◽  
Jeff Chou ◽  
Catherine J. Baty ◽  
Nancy A. Burke ◽  
Simon C. Watkins ◽  
...  

ABSTRACT Calpain activity is required for de-adhesion of the cell body and rear to enable productive locomotion of adherent cells during wound repair and tumor invasion. Growth factors activate m-calpain (calpain 2, CAPN2) via ERK/mitogen-activated protein kinases, but only when these kinases are localized to the plasma membrane. We thus hypothesized that m-calpain is activated by epidermal growth factor (EGF) only when it is juxtaposed to the plasma membrane secondary to specific docking. Osmotic disruption of NR6 fibroblasts expressing the EGF receptor demonstrated m-calpain being complexed with the substratum-adherent membrane with this increasing in an EGF-dependent manner. m-Calpain colocalized with phosphoinositide biphosphate (PIP2) with exogenous phospholipase C removal of phosphoinositides, specifically, PI(4,5)P2 but not PI(4)P1 or PIP3, releasing the bound m-calpain. Downregulation of phosphoinositide production by 1-butanol resulted in diminished PIP2 in the plasma membrane and eliminated EGF-induced calpain activation. This PIP2-binding capacity resided in domain III of calpain, which presents a putative C2-like domain. This active conformation of this domain appears to be partially masked in the holoenzyme as both activation of m-calpain by phosphorylation at serine 50 and expression of constitutively active phosphorylation mimic glutamic acid-increased m-calpain binding to the membrane, consistent with blockade of this cascade diminishing membrane association. Importantly, we found that m-calpain was enriched toward the rear of locomoting cells, which was more pronounced in the plasma membrane footprints; EGF further enhanced this enrichment, in line with earlier reports of loss of PIP2 in lamellipodia of motile cells. These data support a model of m-calpain binding to PIP2 concurrent with and likely to enable ERK activation and provides a mechanism by which cell de-adhesion is directed to the cell body and tail as phospholipase C-γ hydrolyzes PIP2 in the protruding lamellipodia.


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