The maturation of mammalian oocytes in vitro can be stimulated by gonadotropins (follicle-stimulating hormone, FSH) or their intrafollicular mediator, epidermal growth factor (EGF)-like peptide-amphiregulin (AREG). We have shown previously that in pig cumulus-oocyte complexes (COCs), FSH induces expression and the synthesis of AREG that binds to EGF receptor (EGFR) and activates the mitogen-activated protein kinase 3/1 (MAPK3/1) signaling pathway. However, in this study we found that FSH also caused a rapid activation of MAPK3/1 in the cumulus cells, which cannot be explained by the de novo synthesis of AREG. The rapid MAPK3/1 activation required EGFR tyrosine kinase (TK) activity, was sensitive to SRC proto-oncogene non-receptor tyrosine kinase (SRC)-family and protein kinase C (PKC) inhibitors, and was resistant to inhibitors of protein kinase A (PKA) and metalloproteinases. AREG also induced the rapid activation of MAPK3/1 in cumulus cells, but this activation was only dependent on the EGFR TK activity. We conclude that in cumulus cells, FSH induces a rapid activation of MAPK3/1 by the ligand-independent transactivation of EGFR, requiring SRC and PKC activities. This rapid activation of MAPK3/1 precedes the second mechanism participating in the generation and maintenance of active MAPK3/1-the ligand-dependent activation of EGFR depending on the synthesis of EGF-like peptides.
- MeSH
- aktivace transkripce MeSH
- amfiregulin metabolismus MeSH
- erbB receptory metabolismus MeSH
- extracelulárním signálem regulované MAP kinasy genetika MeSH
- folikuly stimulující hormon farmakologie MeSH
- IVM techniky MeSH
- kultivované buňky MeSH
- kumulární buňky cytologie účinky léků metabolismus MeSH
- mitogenem aktivovaná proteinkinasa 1 genetika MeSH
- mitogenem aktivovaná proteinkinasa 3 genetika MeSH
- oocyty cytologie účinky léků metabolismus MeSH
- prasata MeSH
- signální transdukce účinky léků MeSH
- skupina kinas odvozených od src-genu metabolismus MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The surge in luteinizing hormone (LH) in preovulatory ovarian follicles triggers the resumption of oocyte meiosis accompanied by expansion of surrounding cumulus cells and ovulation of cumulus-oocyte complexes (COCs) into the oviduct. Over the last 15 years, substantial progress has been made in elucidating the key pathways by which the LH signal spreads within the preovulatory follicle and in identifying the molecules responsible for maintaining oocyte arrest and meiosis resumption. It is now clear that the adenylcyclase-mediated rise in intracellular cyclic adenosine monophosphate leads to activation of the epidermal growth factor receptor (EGFR) network in granulosa and cumulus cells. This signaling network can control the transcription of key genes required for cell metabolism, cumulus expansion, and oocyte meiosis resumption. In addition, EGFR signaling is involved in the regulation of gap junctional communication within follicular somatic cells, and in this way it can control the diffusion of meiosis-arresting molecules as well as energy substrates into the oocyte. Thus, the proper functioning of the follicular EGFR network is a vital precondition for the production of matured and developmentally competent oocytes. However, most current in vitro maturation systems are based on a culture of COCs isolated from growing follicles, in which function of the EGFR network may be insufficient for promoting oocyte meiotic and developmental competence. This review focuses on research identifying the importance of the EGFR signaling in somatic follicular cells for oocyte meiotic and developmental competence, and on special approaches to the culture of COCs isolated from growing follicles to promote oocyte quality.
- MeSH
- erbB receptory genetika metabolismus MeSH
- meióza fyziologie MeSH
- oocyty fyziologie MeSH
- savci fyziologie MeSH
- signální transdukce fyziologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
In vivo, resumption of oocyte meiosis occurs in large ovarian follicles after the preovulatory surge of luteinizing hormone (LH). The LH surge leads to the activation of a broad signaling network in mural granulosa cells equipped with LH receptors. The signals generated in the mural granulosa cells are further augmented by locally produced peptides or steroids and transferred to the cumulus cell compartment and the oocyte itself. Over the last decade, essential progress has been made in the identification of molecular events associated with the final maturation and ovulation of mammalian oocytes. All new evidence argues for a multiple roles of mitogen-activated protein kinase 3/1 (MAPK3/1) in the gonadotropin-induced ovulation processes. However, the knowledge of gonadotropin-induced signaling pathways leading to MAPK3/1 activation in follicular cells seems limited. To date, only the LH-induced transactivation of the epidermal growth factor receptor/MAPK3/1 pathway has been described in granulosa/cumulus cells even though other mechanisms of MAPK3/1 activation have been detected in other types of cells. In this review, we aimed to summarize recent advances in the elucidation of gonadotropin-induced mechanisms leading to the activation of MAPK3/1 in preovulatory follicles and cultured cumulus-oocyte complexes and to point out a specific role of this kinase in the processes accompanying final maturation of the mammalian oocyte.
- MeSH
- folikulární buňky metabolismus MeSH
- MAP kinasový signální systém genetika MeSH
- meióza fyziologie MeSH
- mitogenem aktivovaná proteinkinasa 1 metabolismus MeSH
- mitogenem aktivovaná proteinkinasa 3 metabolismus MeSH
- mutace MeSH
- myši MeSH
- oocyty fyziologie MeSH
- steroidy biosyntéza MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
The aim of this work was to assess the FSH-stimulated expression of epidermal growth factor (EGF)-like peptides in cultured cumulus-oocyte complexes (COCs) and to find out the effect of the peptides on cumulus expansion, oocyte maturation, and acquisition of developmental competence in vitro. FSH promptly stimulated expression of amphiregulin (AREG) and epiregulin (EREG), but not betacellulin (BTC) in the cultured COCs. Expression of AREG and EREG reached maximum at 2 or 4 h after FSH addition respectively. FSH also significantly stimulated expression of expansion-related genes (PTGS2, TNFAIP6, and HAS2) in the COCs at 4 and 8 h of culture, with a significant decrease at 20 h of culture. Both AREG and EREG also increased expression of the expansion-related genes; however, the relative abundance of mRNA for each gene was much lower than in the FSH-stimulated COCs. In contrast to FSH, AREG and EREG neither stimulated expression of CYP11A1 in the COCs nor an increase in progesterone production by cumulus cells. AREG and EREG stimulated maturation of oocytes and expansion of cumulus cells, although the percentage of oocytes that had reached metaphase II was significantly lower when compared to FSH-induced maturation. Nevertheless, significantly more oocytes stimulated with AREG and/or EREG developed to blastocyst stage after parthenogenetic activation when compared to oocytes stimulated with FSH alone or combinations of FSH/LH or pregnant mares serum gonadotrophin/human chorionic gonadotrophin. We conclude that EGF-like peptides do not mimic all effects of FSH on the cultured COCs; nevertheless, they yield oocytes with superior developmental competence.
- MeSH
- buněčná diferenciace účinky léků genetika MeSH
- embryonální vývoj účinky léků genetika MeSH
- epidermální růstový faktor chemie farmakologie MeSH
- folikuly stimulující hormon farmakologie MeSH
- gonadotropiny farmakologie MeSH
- kultivace embrya MeSH
- kultivované buňky MeSH
- kumulární buňky účinky léků metabolismus fyziologie MeSH
- oocyty účinky léků metabolismus fyziologie MeSH
- oogeneze účinky léků genetika MeSH
- partenogeneze účinky léků genetika fyziologie MeSH
- peptidové fragmenty chemie farmakologie MeSH
- prasata genetika metabolismus fyziologie MeSH
- proliferace buněk účinky léků MeSH
- stanovení celkové genové exprese MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Český trh s léky má za sebou první polovinu roku 2008, tedy roku, ve kterém bychom měli být svědky výsledků prvních reformních kroků ve zdravotnictví. Zavedení regulačních poplatků od ledna 2008 a jejich dopad na prodeje léků ve čtvrtém čtvrtletí roku 2007 a prvním čtvrtletí roku 2008 jsme diskutovali ve druhém letošním čísle Pharm Business Magazine. Nyní máme příležitost posoudit jejich vliv na český farmaceutický trh v ukončeném prvním pololetí 2008.
- MeSH
- lékové předpisy MeSH
- léky bez předpisu MeSH
- spotřeba léčiv MeSH
- veřejné lékárenské služby statistika a číselné údaje MeSH
- Geografické názvy
- Česká republika MeSH
- MeSH
- farmaceutický průmysl MeSH
- lékové předpisy MeSH
- léky bez předpisu izolace a purifikace MeSH
- spotřeba léčiv MeSH
- Geografické názvy
- Česká republika MeSH
