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The Effect of EGF - like Peptides on Cumulus-Oocyte Complexes
Blaha, Milan ; Němcová, Lucie (advisor) ; Krylov, Vladimír (referee)
In mammals, the ovarian cycle is controlled by follicle-stimulating hormone (FSH) and luteinizing hormone (LH), secreted by the anterior lobe of the pituitary gland. FSH is assumed to be essential for follicle growth. LH is required for the terminal phases of follicle growth, estrogen synthesis, ovulation, development of the corpus luteum and progesterone synthesis. Although cumulus cells and oocytes lack LH-receptors, LH causes cumulus expansion and meiosis resumption. The effect of LH is mediated via EGF-like peptides - amphiregulin (AREG), epiregulin (EREG) and betacellulin (BTC). The precursors of these peptides are present in the mural granulosa cells and EGF-like peptides are released by activation of metalloproteases in response to LH-stimulus. The aim of this thesis is to present EGF-like peptides in the wide context of the molecular mechanisms regulating the late phases of folliculogenesis and meiotic maturation of oocytes.
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Signaling pathways and genes regulating gonadotropin-induced maturation of porcine oocytes and cumulus expansion
Blaha, Milan ; Němcová, Lucie (advisor) ; Král, Jiří (referee)
In vitro, meotic maturation of porcine oocytes and cumulus expansion are induced by FSH and EGF-like peptides AREG and EREG. FSH and EGF-like peptides induce expression of cumulus expansion-related genes (HAS2, PTGS2 and TNFAIP6). To define signaling pathways that control FSH- and AREG-induced cumulus expansion, porcine cumulus-oocyte complexes were treated with specific protein kinase inhibitors. Inhibitors of MAPK3/1, MAPK14 and ERBB1 significantly reduced both FSH- and AREG-induced expression of HAS2, PTGS2 and TNFAIP6. These inhibitors decreased FSH/LH-induced expression of AREG and EREG in mural granulosa cells. Surprisingly, inhibitor of PKA had no effect on AREG expression in cumulus-oocyte complexes but the inhibitor decreased expression of TNFAIP6 induced by AREG. Inhibitor of PI3K increased expression levels of AREG and PTGS2 but EREG, HAS2 and TNFAIP6 were reduced. Expression levels of the cumulus expansion-related genes were not affected by an analog of cGMP (8-CPT-cGMP). However, 8-CPT-cGMP blocked spontaneous in vitro meiotic maturation of porcine oocytes and its effect was abolished by FSH. Key words: cumulus expansion, cumulus expansion-related genes, meotic maturation, FSH, amphiregulin, cGMP
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Signaling pathways and genes regulating oocyte maturation in pig
Blaha, Milan
The gonadotropin-induced resumption of meiosis and cumulus expansion in preovulatory follicles is preceded by expression of epidermal growth factor (EGF)-like factors, amphiregulin (AREG) and epiregulin (EREG), in mural granulosa and cumulus cells. In vitro, the EGF-like peptides are also produced in cumulus cells upon stimulation by FSH. Both FSH and the EGF-like peptides stimulate resumption of meiosis and cumulus expansion in vitro via activation of a broad signaling network in cumulus cells. To define signaling pathways that drive FSH- and AREG-induced cumulus expansion and meiotic resumption, in vitro cultured pig cumulus-oocyte complexes (COCs) were treated with specific protein kinase inhibitors. The results document that FSH-stimulated, but not the AREG-stimulated resumption of meiosis, depends on the PKA and MAPK14 activities; both modes of stimulation require activation of EGFR and MAPK3/1. To characterize the effects of FSH and EGF-like peptides on gene expression in cumulus cells, transcriptomes of cumulus cells were analysed using microarray approach. Both FSH and AREG+EREG increased the expression of genes associated with regulation of cell proliferation, blood coagulation and extracellular matrix remodeling. In contrast to AREG+EREG, FSH also increased the expression of genes coding...
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Signaling pathways and genes regulating oocyte maturation in pig
Blaha, Milan ; Procházka, Radek (advisor) ; Krylov, Vladimír (referee) ; Petr, Jaroslav (referee)
The gonadotropin-induced resumption of meiosis and cumulus expansion in preovulatory follicles is preceded by expression of epidermal growth factor (EGF)-like factors, amphiregulin (AREG) and epiregulin (EREG), in mural granulosa and cumulus cells. In vitro, the EGF-like peptides are also produced in cumulus cells upon stimulation by FSH. Both FSH and the EGF-like peptides stimulate resumption of meiosis and cumulus expansion in vitro via activation of a broad signaling network in cumulus cells. To define signaling pathways that drive FSH- and AREG-induced cumulus expansion and meiotic resumption, in vitro cultured pig cumulus-oocyte complexes (COCs) were treated with specific protein kinase inhibitors. The results document that FSH-stimulated, but not the AREG-stimulated resumption of meiosis, depends on the PKA and MAPK14 activities; both modes of stimulation require activation of EGFR and MAPK3/1. To characterize the effects of FSH and EGF-like peptides on gene expression in cumulus cells, transcriptomes of cumulus cells were analysed using microarray approach. Both FSH and AREG+EREG increased the expression of genes associated with regulation of cell proliferation, blood coagulation and extracellular matrix remodeling. In contrast to AREG+EREG, FSH also increased the expression of genes coding...
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Signaling pathways and genes regulating oocyte maturation in pig
Blaha, Milan
The gonadotropin-induced resumption of meiosis and cumulus expansion in preovulatory follicles is preceded by expression of epidermal growth factor (EGF)-like factors, amphiregulin (AREG) and epiregulin (EREG), in mural granulosa and cumulus cells. In vitro, the EGF-like peptides are also produced in cumulus cells upon stimulation by FSH. Both FSH and the EGF-like peptides stimulate resumption of meiosis and cumulus expansion in vitro via activation of a broad signaling network in cumulus cells. To define signaling pathways that drive FSH- and AREG-induced cumulus expansion and meiotic resumption, in vitro cultured pig cumulus-oocyte complexes (COCs) were treated with specific protein kinase inhibitors. The results document that FSH-stimulated, but not the AREG-stimulated resumption of meiosis, depends on the PKA and MAPK14 activities; both modes of stimulation require activation of EGFR and MAPK3/1. To characterize the effects of FSH and EGF-like peptides on gene expression in cumulus cells, transcriptomes of cumulus cells were analysed using microarray approach. Both FSH and AREG+EREG increased the expression of genes associated with regulation of cell proliferation, blood coagulation and extracellular matrix remodeling. In contrast to AREG+EREG, FSH also increased the expression of genes coding...
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Signaling pathways and genes regulating gonadotropin-induced maturation of porcine oocytes and cumulus expansion
Blaha, Milan ; Němcová, Lucie (advisor) ; Král, Jiří (referee)
In vitro, meotic maturation of porcine oocytes and cumulus expansion are induced by FSH and EGF-like peptides AREG and EREG. FSH and EGF-like peptides induce expression of cumulus expansion-related genes (HAS2, PTGS2 and TNFAIP6). To define signaling pathways that control FSH- and AREG-induced cumulus expansion, porcine cumulus-oocyte complexes were treated with specific protein kinase inhibitors. Inhibitors of MAPK3/1, MAPK14 and ERBB1 significantly reduced both FSH- and AREG-induced expression of HAS2, PTGS2 and TNFAIP6. These inhibitors decreased FSH/LH-induced expression of AREG and EREG in mural granulosa cells. Surprisingly, inhibitor of PKA had no effect on AREG expression in cumulus-oocyte complexes but the inhibitor decreased expression of TNFAIP6 induced by AREG. Inhibitor of PI3K increased expression levels of AREG and PTGS2 but EREG, HAS2 and TNFAIP6 were reduced. Expression levels of the cumulus expansion-related genes were not affected by an analog of cGMP (8-CPT-cGMP). However, 8-CPT-cGMP blocked spontaneous in vitro meiotic maturation of porcine oocytes and its effect was abolished by FSH. Key words: cumulus expansion, cumulus expansion-related genes, meotic maturation, FSH, amphiregulin, cGMP
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The Effect of EGF - like Peptides on Cumulus-Oocyte Complexes
Blaha, Milan ; Krylov, Vladimír (referee) ; Němcová, Lucie (advisor)
In mammals, the ovarian cycle is controlled by follicle-stimulating hormone (FSH) and luteinizing hormone (LH), secreted by the anterior lobe of the pituitary gland. FSH is assumed to be essential for follicle growth. LH is required for the terminal phases of follicle growth, estrogen synthesis, ovulation, development of the corpus luteum and progesterone synthesis. Although cumulus cells and oocytes lack LH-receptors, LH causes cumulus expansion and meiosis resumption. The effect of LH is mediated via EGF-like peptides - amphiregulin (AREG), epiregulin (EREG) and betacellulin (BTC). The precursors of these peptides are present in the mural granulosa cells and EGF-like peptides are released by activation of metalloproteases in response to LH-stimulus. The aim of this thesis is to present EGF-like peptides in the wide context of the molecular mechanisms regulating the late phases of folliculogenesis and meiotic maturation of oocytes.
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