The Experts below are selected from a list of 2469 Experts worldwide ranked by ideXlab platform

Anna Marie Kenney - One of the best experts on this subject based on the ideXlab platform.

  • abstract 3445 the role of p38 MAPK14 in cerebellar granule neuron precursor proliferation and medulloblastoma
    Cancer Research, 2011
    Co-Authors: Cemile G Guldal, Lori A Mainwaring, Anna Marie Kenney
    Abstract:

    Development of the cerbellum occurs primarily postnatally and is marked by a rapid proliferation of cerebellar granule neuron precursors (CGNPs). This proliferation requires the activity of the mitogen Sonic Hedgehog (Shh). CGNPs are proposed to be the cells of origin for some classes of medulloblastoma (MB), the most common solid pediatric tumor, making their proliferation an attractive target for cancer therapy. Since MAP kinases play important roles in many aspects of development, proliferation, and cancer, we investigated if any of the three major classes of MAP kinases were involved in Shh-driven CGNP proliferation. We have previously shown that p42/p44 ERK MAP kinases are not involved in Shh signaling in CGNP proliferation. We have also shown that JNK/SAP kinases are not involved in Shh-driven proliferation. However, p38/MAPK14 is induced and activated in proliferating CGNPs compared to CGNPs that exit the cell cycle and differentiate in the absence of Shh. Other known pathway components upstream and downstream of MAPK14, such as ASK1, MKK3 and ATF-2, are also activated in the presence of Shh. Antioxidants such as lipoic acid and n-acetyl-cysteine that relieve oxidative stress reduced Shh-induced activation of MAPK14 and caused a marked decrease in CGNP proliferation measured by Ki67 and BrdU staining. Knocking down p38 in CGNPs also causes a marked decrease in Shh-dependent proliferation and an increase in apoptosis, which indicates a role for MAPK14 in CGNP survival. We are currently investigating the mechanism of Shh regulation of p38 MAPK pathway, which will lead to a better understanding of CGNP proliferation, cerebellar development, and MB progression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3445. doi:10.1158/1538-7445.AM2011-3445

  • Abstract 3445: The role of p38/MAPK14 in cerebellar granule neuron precursor proliferation and medulloblastoma
    Cancer Research, 2011
    Co-Authors: Cemile G Guldal, Lori A Mainwaring, Anna Marie Kenney
    Abstract:

    Development of the cerbellum occurs primarily postnatally and is marked by a rapid proliferation of cerebellar granule neuron precursors (CGNPs). This proliferation requires the activity of the mitogen Sonic Hedgehog (Shh). CGNPs are proposed to be the cells of origin for some classes of medulloblastoma (MB), the most common solid pediatric tumor, making their proliferation an attractive target for cancer therapy. Since MAP kinases play important roles in many aspects of development, proliferation, and cancer, we investigated if any of the three major classes of MAP kinases were involved in Shh-driven CGNP proliferation. We have previously shown that p42/p44 ERK MAP kinases are not involved in Shh signaling in CGNP proliferation. We have also shown that JNK/SAP kinases are not involved in Shh-driven proliferation. However, p38/MAPK14 is induced and activated in proliferating CGNPs compared to CGNPs that exit the cell cycle and differentiate in the absence of Shh. Other known pathway components upstream and downstream of MAPK14, such as ASK1, MKK3 and ATF-2, are also activated in the presence of Shh. Antioxidants such as lipoic acid and n-acetyl-cysteine that relieve oxidative stress reduced Shh-induced activation of MAPK14 and caused a marked decrease in CGNP proliferation measured by Ki67 and BrdU staining. Knocking down p38 in CGNPs also causes a marked decrease in Shh-dependent proliferation and an increase in apoptosis, which indicates a role for MAPK14 in CGNP survival. We are currently investigating the mechanism of Shh regulation of p38 MAPK pathway, which will lead to a better understanding of CGNP proliferation, cerebellar development, and MB progression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3445. doi:10.1158/1538-7445.AM2011-3445

  • abstract lb 13 the role of p38 MAPK14 in sonic hedgehog driven cgnp proliferation
    Cancer Research, 2010
    Co-Authors: Guldal G Cemile, Lori A Mainwaring, Susana R Parathath, Anna Marie Kenney
    Abstract:

    Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Development of the cerbellum occurs primarily postnatally and is marked by a rapid proliferation of cerebellar granule neuron precursors (CGNPs). This proliferation requires the activity of the mitogen Sonic Hedgehog (Shh). The rapid proliferation stage of CGNPs has led to speculation that they are the cells of origin for some classes of medulloblastoma, the most common solid pediatric tumor. Since MAP kinases play important roles in many aspects of development, proliferation, and cancer we investigated if any of the three major classes of MAP kinases were involved in Shh-driven CGNP proliferation. We have previously shown that p42/p44 ERK MAP kinases are not involved in Shh signaling in CGNP proliferation. We have also shown that JNK/SAP kinases are not involved in Shh-driven proliferation. However, p38/MAPK14 is induced and activated in proliferating CGNPs compared to CGNPs that exit the cell cycle and differentiate in the absence of Shh. Other known pathway components upstream and downstream of MAPK14, such as ASK1, MKK3 and ATF-2, are also activated in the presence of Shh. Antioxidants such as lipoic acid and n-acetyl-cysteine that relieve oxidative stress reduced Shh-induced activation of MAPK14 and caused a marked decrease in CGNP proliferation measured by Ki67 and BrdU staining. We are currently investigating the role of oxidative stress and MAPK14 in CGNP proliferation by over-expressing and knocking down MAPK14 in CGNPs under oxidative stress conditions. Preliminary data suggests that knocking down MAPK14 reduces CGNP proliferation. Elucidating the role of MAPK14 pathway in CGNP proliferation will not only help us understand normal cerebellum development but may also lead to possible therapies for diseases where constitutive Shh signaling has been shown to play a role such as some classes of medulloblastoma and Gorlin's syndrome. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-13.

  • Abstract LB-13: The role of p38/MAPK14 in Sonic Hedgehog-driven CGNP proliferation
    Cancer Research, 2010
    Co-Authors: Guldal G Cemile, Lori A Mainwaring, Susana R Parathath, Anna Marie Kenney
    Abstract:

    Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Development of the cerbellum occurs primarily postnatally and is marked by a rapid proliferation of cerebellar granule neuron precursors (CGNPs). This proliferation requires the activity of the mitogen Sonic Hedgehog (Shh). The rapid proliferation stage of CGNPs has led to speculation that they are the cells of origin for some classes of medulloblastoma, the most common solid pediatric tumor. Since MAP kinases play important roles in many aspects of development, proliferation, and cancer we investigated if any of the three major classes of MAP kinases were involved in Shh-driven CGNP proliferation. We have previously shown that p42/p44 ERK MAP kinases are not involved in Shh signaling in CGNP proliferation. We have also shown that JNK/SAP kinases are not involved in Shh-driven proliferation. However, p38/MAPK14 is induced and activated in proliferating CGNPs compared to CGNPs that exit the cell cycle and differentiate in the absence of Shh. Other known pathway components upstream and downstream of MAPK14, such as ASK1, MKK3 and ATF-2, are also activated in the presence of Shh. Antioxidants such as lipoic acid and n-acetyl-cysteine that relieve oxidative stress reduced Shh-induced activation of MAPK14 and caused a marked decrease in CGNP proliferation measured by Ki67 and BrdU staining. We are currently investigating the role of oxidative stress and MAPK14 in CGNP proliferation by over-expressing and knocking down MAPK14 in CGNPs under oxidative stress conditions. Preliminary data suggests that knocking down MAPK14 reduces CGNP proliferation. Elucidating the role of MAPK14 pathway in CGNP proliferation will not only help us understand normal cerebellum development but may also lead to possible therapies for diseases where constitutive Shh signaling has been shown to play a role such as some classes of medulloblastoma and Gorlin's syndrome. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-13.

Joëlle Dupont - One of the best experts on this subject based on the ideXlab platform.

  • Potential Involvement of Several Signaling Pathways in Initiation of the Chicken Acrosome Reaction
    Biology of Reproduction, 2009
    Co-Authors: Manuela Lemoine, Joëlle Dupont, Vanaïque Guillory, Sophie Tesseraud, Elisabeth Blesbois
    Abstract:

    Avian sperm biology has demonstrated specific features in preparation for fertilization. For example, capacitationlike processes and motility hyperactivation do not exist in the form described in mammals. The present study investigated the potential involvement of several signaling pathways, including protein kinase A (PKA), phosphatidylinositol 3 kinase (PIK3), mitogen-activated protein kinase 3/1 (MAPK3/1), and MAPK14 in the chicken acrosome reaction (AR). The presence in chicken spermatozoa of key proteins involved in these signaling pathways (i.e., cAMP-responsive element-binding protein [CREB], AKT, MAPK1, and MAPK14 and their respective phosphorylated forms) was detected using immunoblotting and localized by immunocytochemistry, mainly in the heads. The potential involvement of these pathways in the AR induced by inner perivitelline layer (IPVL) and Ca2+ was then examined using specific inhibitors and phosphorylation status measurements. The effects of the specific inhibitors on motility were also m...

  • Glycogen synthase kinase 3B in bovine oocytes and granulosa cells: possible involvement in meiosis during in vitro maturation.
    Reproduction, 2009
    Co-Authors: Svetlana Uzbekova, Mohamad Salhab, Christine Perreau, Pascal Mermillod, Joëlle Dupont
    Abstract:

    Glycogen synthase kinase 3 (GSK3) regulates cellular metabolism and cell cycle via different signalling pathways. In response to insulin and growth factors GSK3 is serine-phosphorylated and inactivated. We analysed GSK3B expression and activation in bovine cumulus cells (CC) and oocytes at different meiotic stages in vitro in parallel with MAP kinases ERK (MAPK3/MAPK1) and p38 (MAPK14). GSK3B localised to cytoplasm in granulosa cells and in oocytes throughout folliculogenesis. In mature metaphase-II (MII) oocytes, GSK3B was concentrated to the region of midzone between the oocyte and the first polar body, as well as active phospho-Thr Aurora A kinase (AURKA). During in vitro maturation (IVM), in oocytes, phospho-Ser⁹-GSK3B level increased as well as phospho-MAPK3/MAPK1, while phospho-MAPK14 decreased. In CC, phospho-MAPK14 increased upon germinal vesicle breakdown (GVBD)/metaphase-I (MI) and then decreased during transition to MII. Administration of inhibitors of GSK3 activity (lithium chloride or 2'Z,3'E -6-bromoindirubin-3'-oxime) rapidly increased phospho-Ser⁹-GSK3B, and led to transient decrease of phospho-MAPK3/MAPK1 and to durable enhancing of phospho-MAPK14 in granulosa primary cell culture. GSK3 inhibitors during IVM diminished cumulus expansion and delayed meiotic progression. In cumulus, phospho-MAPK14 level was significantly higher in the presence of inhibitors, comparing with control, through the time of MI/MII transition. In oocytes, phospho-GSK3B was increased and phospho-MAPK3/MAPK1 was decreased before GVBD and oocytes were mainly arrested at MI. Therefore, GSK3B might regulate oocyte meiosis, notably MI/MII transition being the part of MAPK3/1 and MAPK14 pathways in oocytes and CC. GSK3B might be also involved in the local activation of AURKA that controls this transition.

  • effects of metformin on bovine granulosa cells steroidogenesis possible involvement of adenosine 5 monophosphate activated protein kinase ampk
    Biology of Reproduction, 2007
    Co-Authors: Lucie Tosca, Svetlana Uzbekova, Christine Chabrolle, Joëlle Dupont
    Abstract:

    In mammals, IGFs are important for the proliferation and steroidogenesis of ovarian cells. Metformin is an insulin sensitizer molecule used for the treatment of the infertility of women with polycystic ovary syndrome. It is, however, unclear whether metformin acts on ovarian cells. Adenosine 5 0 monophosphate-activated protein kinase (AMPK) is involved in metformin action in various cell types. We investigated the effects of metformin on bovine granulosa cell steroidogenesis in response to IGF1 and FSH, and studied AMPK in bovine ovaries. In granulosa cells from small follicles, metformin (10 mM) reduced production of both progesterone and estradiol and decreased the abundance of HSD3B, CYP11A1, and STAR proteins in presence or absence of FSH (10 � 8 M) and IGF1 (10 � 8 M). In cows, the different subunits of AMPK are expressed in various ovarian cells including granulosa and theca cells, corpus luteum, and oocytes. In bovine granulosa cells from small follicles, metformin, like AICAR (1 mM) a pharmaceutical activator of AMPK, increased phosphorylation of both Thr172 of AMPK alpha and Ser 79 of ACACA (Acetyl-CoA Carboxylase). Both metformin and AICAR treatment reduced progesterone and estradiol secretion in presence or absence of FSH and IGF1. Metformin decreased phosphorylation levels of MAPK3/MAPK1 and MAPK14 in a dose- and time-dependent manner. The adenovirus-mediated production of dominant negative AMPK abolished the effects of metformin on secretion of progesterone and estradiol and on MAPK3/MAPK1 phosphorylation but not on MAPK14 phosphorylation. Thus, in bovine granulosa cells, metformin decreases steroidogenesis and MAPK3/MAPK1 phosphorylation through AMPK activation. AMPK, cumulus cells, granulosa cells, metformin ovary, progesterone, signal transduction, steroid hormones

  • Effects of Metformin on Bovine Granulosa Cells Steroidogenesis: Possible Involvement of Adenosine 5′ Monophosphate-Activated Protein Kinase (AMPK)
    Biology of Reproduction, 2006
    Co-Authors: Lucie Tosca, Svetlana Uzbekova, Christine Chabrolle, Joëlle Dupont
    Abstract:

    In mammals, IGFs are important for the proliferation and steroidogenesis of ovarian cells. Metformin is an insulin sensitizer molecule used for the treatment of the infertility of women with polycystic ovary syndrome. It is, however, unclear whether metformin acts on ovarian cells. Adenosine 5 0 monophosphate-activated protein kinase (AMPK) is involved in metformin action in various cell types. We investigated the effects of metformin on bovine granulosa cell steroidogenesis in response to IGF1 and FSH, and studied AMPK in bovine ovaries. In granulosa cells from small follicles, metformin (10 mM) reduced production of both progesterone and estradiol and decreased the abundance of HSD3B, CYP11A1, and STAR proteins in presence or absence of FSH (10 � 8 M) and IGF1 (10 � 8 M). In cows, the different subunits of AMPK are expressed in various ovarian cells including granulosa and theca cells, corpus luteum, and oocytes. In bovine granulosa cells from small follicles, metformin, like AICAR (1 mM) a pharmaceutical activator of AMPK, increased phosphorylation of both Thr172 of AMPK alpha and Ser 79 of ACACA (Acetyl-CoA Carboxylase). Both metformin and AICAR treatment reduced progesterone and estradiol secretion in presence or absence of FSH and IGF1. Metformin decreased phosphorylation levels of MAPK3/MAPK1 and MAPK14 in a dose- and time-dependent manner. The adenovirus-mediated production of dominant negative AMPK abolished the effects of metformin on secretion of progesterone and estradiol and on MAPK3/MAPK1 phosphorylation but not on MAPK14 phosphorylation. Thus, in bovine granulosa cells, metformin decreases steroidogenesis and MAPK3/MAPK1 phosphorylation through AMPK activation. AMPK, cumulus cells, granulosa cells, metformin ovary, progesterone, signal transduction, steroid hormones

Changhyun Oh - One of the best experts on this subject based on the ideXlab platform.

  • discovery of a potent p38α MAPK14 kinase inhibitor synthesis in vitro in vivo biological evaluation and docking studies
    European Journal of Medicinal Chemistry, 2019
    Co-Authors: Mohammed I Elgamal, Hanan S Anbar, Hamadeh Tarazi, Changhyun Oh
    Abstract:

    Abstract This article reports the synthesis of new triarylpyrazole derivatives possessing urea or amide linker, and their biological activities at molecular, cellular, and in vivo levels. Compound 2b was the most potent inhibitor of p38α/MAPK14 kinase (IC50 = 22 nM) among this series. Molecular docking studies were conducted to understand the kinase inhibitory variations and the basis of selectivity. Compound 2b was able to inhibit p38α/MAPK14 kinase inside HEK293 cells in nanoBRET cellular kinase assay with EC50 value of 0.55 μM, comparable to the potency of dasatinib. Compound 2b inhibited TNF-α production in lipopolysaccharide-induced THP-1 cells with IC50 value of 58 nM. In addition, compound 2b showed low potency against hERG. It is 622.38 times less potent than E−4031 against hERG, so the risk of cardiotoxicity of the compound is very minimal. Compound 2b showed also high plasma stability in vitro in human and rat plasmas. The in vivo PK profile of compound 2b is acceptable, and its antiinflammatory effect was comparable to diclofenac with no ulcerogenic side effect on stomach.

  • Discovery of a potent p38α/MAPK14 kinase inhibitor: Synthesis, in vitro/in vivo biological evaluation, and docking studies
    European Journal of Medicinal Chemistry, 2019
    Co-Authors: Mohammed I. El-gamal, Hanan S Anbar, Hamadeh Tarazi, Changhyun Oh
    Abstract:

    Abstract This article reports the synthesis of new triarylpyrazole derivatives possessing urea or amide linker, and their biological activities at molecular, cellular, and in vivo levels. Compound 2b was the most potent inhibitor of p38α/MAPK14 kinase (IC50 = 22 nM) among this series. Molecular docking studies were conducted to understand the kinase inhibitory variations and the basis of selectivity. Compound 2b was able to inhibit p38α/MAPK14 kinase inside HEK293 cells in nanoBRET cellular kinase assay with EC50 value of 0.55 μM, comparable to the potency of dasatinib. Compound 2b inhibited TNF-α production in lipopolysaccharide-induced THP-1 cells with IC50 value of 58 nM. In addition, compound 2b showed low potency against hERG. It is 622.38 times less potent than E−4031 against hERG, so the risk of cardiotoxicity of the compound is very minimal. Compound 2b showed also high plasma stability in vitro in human and rat plasmas. The in vivo PK profile of compound 2b is acceptable, and its antiinflammatory effect was comparable to diclofenac with no ulcerogenic side effect on stomach.

Arnaud Coquelle - One of the best experts on this subject based on the ideXlab platform.

  • MAPK14 p38α confers irinotecan resistance to tp53 defective cells by inducing survival autophagy
    Autophagy, 2012
    Co-Authors: Salomé Paillas, Vincent Denis, Laetitia Marzi, Annick Causse, Nadia Vezziovie, Marc Poirot, Lucile Espert, Hayat Arzouk, Philippe De Medina, Arnaud Coquelle
    Abstract:

    Recently we have shown that the mitogen-activated protein kinase (MAPK) MAPK14/p38α is involved in resistance of colon cancer cells to camptothecin-related drugs. Here we further investigated the cellular mechanisms involved in such drug resistance and showed that, in HCT116 human colorectal adenocarcinoma cells in which TP53 was genetically ablated (HCT116-TP53KO), overexpression of constitutively active MAPK14/p38α decreases cell sensitivity to SN-38 (the active metabolite of irinotecan), inhibits cell proliferation and induces survival-autophagy. Since autophagy is known to facilitate cancer cell resistance to chemotherapy and radiation treatment, we then investigated the relationship between MAPK14/p38α, autophagy and resistance to irinotecan. We demonstrated that induction of autophagy by SN38 is dependent on MAPK14/p38α activation. Finally, we showed that inhibition of MAPK14/p38α or autophagy both sensitizes HCT116-TP53KO cells to drug therapy. Our data proved that the two effects are interrelated, since the role of autophagy in drug resistance required the MAPK14/p38α. Our results highlight the existence of a new mechanism of resistance to camptothecin-related drugs: upon SN38 induction, MAPK14/p38α is activated and triggers survival-promoting autophagy to protect tumor cells against the cytotoxic effects of the drug. Colon cancer cells could thus be sensitized to drug therapy by inhibiting either MAPK14/p38 or autophagy.

  • MAPK14/p38α confers irinotecan resistance to TP53-defective cells by inducing survival autophagy
    Autophagy, 2012
    Co-Authors: Salomé Paillas, Vincent Denis, Nadia Vezzio-vié, Laetitia Marzi, Annick Causse, Marc Poirot, Lucile Espert, Hayat Arzouk, Philippe De Medina, Arnaud Coquelle
    Abstract:

    Recently we have shown that the mitogen-activated protein kinase (MAPK) MAPK14/p38α is involved in resistance of colon cancer cells to camptothecin-related drugs. Here we further investigated the cellular mechanisms involved in such drug resistance and showed that, in HCT116 human colorectal adenocarcinoma cells in which TP53 was genetically ablated (HCT116-TP53KO), overexpression of constitutively active MAPK14/p38α decreases cell sensitivity to SN-38 (the active metabolite of irinotecan), inhibits cell proliferation and induces survival-autophagy. Since autophagy is known to facilitate cancer cell resistance to chemotherapy and radiation treatment, we then investigated the relationship between MAPK14/p38α, autophagy and resistance to irinotecan. We demonstrated that induction of autophagy by SN38 is dependent on MAPK14/p38α activation. Finally, we showed that inhibition of MAPK14/p38α or autophagy both sensitizes HCT116-TP53KO cells to drug therapy. Our data proved that the two effects are interrelated, since the role of autophagy in drug resistance required the MAPK14/p38α. Our results highlight the existence of a new mechanism of resistance to camptothecin-related drugs: upon SN38 induction, MAPK14/p38α is activated and triggers survival-promoting autophagy to protect tumor cells against the cytotoxic effects of the drug. Colon cancer cells could thus be sensitized to drug therapy by inhibiting either MAPK14/p38 or autophagy.

Lucie Tosca - One of the best experts on this subject based on the ideXlab platform.

  • effects of metformin on bovine granulosa cells steroidogenesis possible involvement of adenosine 5 monophosphate activated protein kinase ampk
    Biology of Reproduction, 2007
    Co-Authors: Lucie Tosca, Svetlana Uzbekova, Christine Chabrolle, Joëlle Dupont
    Abstract:

    In mammals, IGFs are important for the proliferation and steroidogenesis of ovarian cells. Metformin is an insulin sensitizer molecule used for the treatment of the infertility of women with polycystic ovary syndrome. It is, however, unclear whether metformin acts on ovarian cells. Adenosine 5 0 monophosphate-activated protein kinase (AMPK) is involved in metformin action in various cell types. We investigated the effects of metformin on bovine granulosa cell steroidogenesis in response to IGF1 and FSH, and studied AMPK in bovine ovaries. In granulosa cells from small follicles, metformin (10 mM) reduced production of both progesterone and estradiol and decreased the abundance of HSD3B, CYP11A1, and STAR proteins in presence or absence of FSH (10 � 8 M) and IGF1 (10 � 8 M). In cows, the different subunits of AMPK are expressed in various ovarian cells including granulosa and theca cells, corpus luteum, and oocytes. In bovine granulosa cells from small follicles, metformin, like AICAR (1 mM) a pharmaceutical activator of AMPK, increased phosphorylation of both Thr172 of AMPK alpha and Ser 79 of ACACA (Acetyl-CoA Carboxylase). Both metformin and AICAR treatment reduced progesterone and estradiol secretion in presence or absence of FSH and IGF1. Metformin decreased phosphorylation levels of MAPK3/MAPK1 and MAPK14 in a dose- and time-dependent manner. The adenovirus-mediated production of dominant negative AMPK abolished the effects of metformin on secretion of progesterone and estradiol and on MAPK3/MAPK1 phosphorylation but not on MAPK14 phosphorylation. Thus, in bovine granulosa cells, metformin decreases steroidogenesis and MAPK3/MAPK1 phosphorylation through AMPK activation. AMPK, cumulus cells, granulosa cells, metformin ovary, progesterone, signal transduction, steroid hormones

  • Effects of Metformin on Bovine Granulosa Cells Steroidogenesis: Possible Involvement of Adenosine 5′ Monophosphate-Activated Protein Kinase (AMPK)
    Biology of Reproduction, 2006
    Co-Authors: Lucie Tosca, Svetlana Uzbekova, Christine Chabrolle, Joëlle Dupont
    Abstract:

    In mammals, IGFs are important for the proliferation and steroidogenesis of ovarian cells. Metformin is an insulin sensitizer molecule used for the treatment of the infertility of women with polycystic ovary syndrome. It is, however, unclear whether metformin acts on ovarian cells. Adenosine 5 0 monophosphate-activated protein kinase (AMPK) is involved in metformin action in various cell types. We investigated the effects of metformin on bovine granulosa cell steroidogenesis in response to IGF1 and FSH, and studied AMPK in bovine ovaries. In granulosa cells from small follicles, metformin (10 mM) reduced production of both progesterone and estradiol and decreased the abundance of HSD3B, CYP11A1, and STAR proteins in presence or absence of FSH (10 � 8 M) and IGF1 (10 � 8 M). In cows, the different subunits of AMPK are expressed in various ovarian cells including granulosa and theca cells, corpus luteum, and oocytes. In bovine granulosa cells from small follicles, metformin, like AICAR (1 mM) a pharmaceutical activator of AMPK, increased phosphorylation of both Thr172 of AMPK alpha and Ser 79 of ACACA (Acetyl-CoA Carboxylase). Both metformin and AICAR treatment reduced progesterone and estradiol secretion in presence or absence of FSH and IGF1. Metformin decreased phosphorylation levels of MAPK3/MAPK1 and MAPK14 in a dose- and time-dependent manner. The adenovirus-mediated production of dominant negative AMPK abolished the effects of metformin on secretion of progesterone and estradiol and on MAPK3/MAPK1 phosphorylation but not on MAPK14 phosphorylation. Thus, in bovine granulosa cells, metformin decreases steroidogenesis and MAPK3/MAPK1 phosphorylation through AMPK activation. AMPK, cumulus cells, granulosa cells, metformin ovary, progesterone, signal transduction, steroid hormones