The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Christine L Mummery - One of the best experts on this subject based on the ideXlab platform.
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defective Paracrine Signalling by tgfβ in yolk sac vasculature of endoglin mutant mice a paradigm for hereditary haemorrhagic telangiectasia
Development, 2004Co-Authors: Rita L C Carvalho, Leon Jonker, Mariejose Goumans, Jonas Larsson, Peter Bouwman, Stefan Karlsson, Peter Ten Dijke, Helen M Arthur, Christine L MummeryAbstract:Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant disorder in humans that is characterised by multisystemic vascular dyplasia and recurrent haemorrhage. Germline mutations in one of two different genes, endoglin or ALK1 can cause HHT. Both are members of the transforming growth factor (TGF) beta receptor family of proteins, and are expressed primarily on the surface of endothelial cells (ECs). Mice that lack endoglin or activin receptor like kinase (ALK) 1 die at mid-gestation as a result of defects in the yolk sac vasculature. Here, we have analyzed TGFbeta Signalling in yolk sacs from endoglin knockout mice and from mice with endothelial-specific deletion of the TGFbeta type II receptor (TbetaRII) or ALK5. We show that TGFbeta/ALK5 Signalling from endothelial cells to adjacent mesothelial cells is defective in these mice, as evidenced by reduced phosphorylation of Smad2. This results in the failure of vascular smooth muscle cells to differentiate and associate with endothelial cells so that blood vessels remain fragile and become dilated. Phosphorylation of Smad2 and differentiation of smooth muscle can be rescued by culture of the yolk sac with exogenous TGFbeta1. Our data show that disruption of TGFbeta Signalling in vascular endothelial cells results in reduced availability of TGFbeta1 protein to promote recruitment and differentiation of smooth muscle cells, and provide a possible explanation for weak vessel walls associated with HHT.
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defective Paracrine Signalling by tgfβ in yolk sac vasculature of endoglin mutant mice a paradigm for hereditary haemorrhagic telangiectasia
Development, 2004Co-Authors: Rita L C Carvalho, Leon Jonker, Mariejose Goumans, Jonas Larsson, Peter Bouwman, Stefan Karlsson, Peter Ten Dijke, Helen M Arthur, Christine L MummeryAbstract:Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant disorder in humans that is characterised by multisystemic vascular dyplasia and recurrent haemorrhage. Germline mutations in one of two different genes, endoglin or ALK1 can cause HHT. Both are members of the transforming growth factor (TGF) beta receptor family of proteins, and are expressed primarily on the surface of endothelial cells (ECs). Mice that lack endoglin or activin receptor like kinase (ALK) 1 die at mid-gestation as a result of defects in the yolk sac vasculature. Here, we have analyzed TGFbeta Signalling in yolk sacs from endoglin knockout mice and from mice with endothelial-specific deletion of the TGFbeta type II receptor (TbetaRII) or ALK5. We show that TGFbeta/ALK5 Signalling from endothelial cells to adjacent mesothelial cells is defective in these mice, as evidenced by reduced phosphorylation of Smad2. This results in the failure of vascular smooth muscle cells to differentiate and associate with endothelial cells so that blood vessels remain fragile and become dilated. Phosphorylation of Smad2 and differentiation of smooth muscle can be rescued by culture of the yolk sac with exogenous TGFbeta1. Our data show that disruption of TGFbeta Signalling in vascular endothelial cells results in reduced availability of TGFbeta1 protein to promote recruitment and differentiation of smooth muscle cells, and provide a possible explanation for weak vessel walls associated with HHT. (Less)
Robert B Gilchrist - One of the best experts on this subject based on the ideXlab platform.
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224 disruption of bi directional oocyte cumulus Paracrine Signalling during oocyte in vitro maturation reduces subsequent mouse fetal survival
Reproduction Fertility and Development, 2008Co-Authors: Robert B Gilchrist, Michelle LaneAbstract:During folliculogenesis, oocyte to cumulus cell (CC) bi-directional communication is essential for normal development of the oocyte. We recently showed that addition of recombinant oocyte Paracrine factor growth differentiation factor 9 (GDF9) during mouse oocyte in vitro maturation (IVM) increased fetal viability. GD.F. 9 signals through SMAD 2/3. Hence the effects of disrupting SMAD2/3 Signalling and its interaction with FSH/EGF during IVM on oocyte development and subsequent fetal outcomes were investigated. Cumulus-oocyte complexes (COCs) from antral follicles (n = 400–500) of eCG treated pre-pubertal (C57BL/6xCBA F1 hybrid) mice were cultured for 18 h in Waymouth's medium+5% serum, with or without 50 mIU/mL FSH and 10ng/mL EGF, SMAD2/3 inhibitor SB-431542 (4µM), or its 0.04% DMSO control. Meiotic maturation was assessed by first polar body (PB1) extrusion immediately after culture. COCs were fertilised and cultured to the blastocyst stage in G1.2/G2.2 media at 37°C in 6%CO2:5%O2:89%N2. Blastocysts were either transferred to pseudo-pregnant Swiss females or differentially stained. Pregnancy outcome was assessed on Day 18 of pregnancy. Inhibition of SMAD 2/3 Signalling did not alter meiotic maturation. No differences were observed in the percentage of blastocysts or hatching blastocysts from cleaved embryos with SMAD2/3 inhibition or the absence of FSH/EGF. However, IVM with SB-431542 or without FSH/EGF significantly decreased (P < 0.001) blastocyst inner cell mass percentages (26% v. 35% control;18% v. 28% control respectively). Fetal survival (fetuses per embryo transferred) of oocytes matured with SB-431542 was significantly decreased (30% v. 50% controls; P < 0.05) although implantation rates and subsequent fetal weights were unaffected. These findings demonstrate the importance of oocyte-CC communication throughout IVM. Inhibition of oocyte Signalling through SMAD2/3 resulted in reduced blastocyst quality and fetal survival; outcomes similar to that of oocytes matured without FSH/EGF. Oocyte–cumulus cell bi-directional communication is thus an important feature of oocyte viability and has a substantial impact on subsequent fetal outcomes.
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molecular basis of oocyte Paracrine Signalling that promotes granulosa cell proliferation
Journal of Cell Science, 2006Co-Authors: Robert B Gilchrist, Lesley J Ritter, Samu Myllymaa, Noora Kaivooja, Rebecca Dragovic, Theresa E Hickey, Olli Ritvos, David G MottersheadAbstract:Oocytes regulate follicle growth by secreting Paracrine growth factors that act on neighbouring granulosa cells (GCs). Those factors identified to date are mainly members of the transforming growth factor-β (TGFβ) superfamily, but little is known about which specific receptor/Signalling system(s) they employ. This study was conducted to determine the requisite pathways utilised by oocytes to promote GC proliferation. We used an established oocyte-secreted mitogen bioassay, where denuded mouse oocytes are co-cultured with mural GCs. Oocytes, growth differentiation factor-9 (GDF9), TGFβ1 and activin-A all promoted GC DNA synthesis, but bone-morphogenetic protein 6 (BMP6) did not. Subsequently, we tested the capacity of various TGFβ superfamily receptor ectodomains (ECD) to neutralise oocyte- or specific growth factor-stimulated GC proliferation. The BMP type-II receptor (BMPR-II) ECD antagonised oocyte and GDF9 bioactivity dose-dependently, but had no or minimal effect on TGFβ1 and activin-A bioactivity, demonstrating its specificity. The TGFβR-II, activinR-IIA and activinR-IIB ECDs all failed to neutralise oocyte- or GDF9-stimulated GC DNA synthesis, whereas they did antagonise the activity of their respective native ligands. An activin receptor-like kinase (ALK) 4/5/7 inhibitor, SB431542, also antagonised both oocyte and GDF9 bioactivity in a dose-dependent manner. Consistent with these findings, oocytes, GDF9 and TGFβ1 all activated SMAD2/3 reporter constructs in transfected GC, and led to phosphorylation of SMAD2 proteins in treated cells. Surprisingly, oocytes did not activate the SMAD1/5/8 pathway in transfected GCs although exogenous BMP6 did. This study indicates that oocyte Paracrine factors primarily utilise a similar Signalling pathway first identified for GDF9 that employs an unusual combination of TGFβ superfamily receptors, the BMPR-II and a SMAD2/3 stimulatory ALK (4, 5 or 7), for transmitting their mitogenic actions in GC. This cell-Signalling pathway may also have relevance in the hypothalamic-pituitary axis and in germ-somatic cell interactions in the testis.
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231 mouse oocyte Paracrine Signalling to cumulus cells by tgf β superfamily molecules is indispensable for cumulus expansion
Reproduction Fertility and Development, 2005Co-Authors: Rebecca Dragovic, Lesley J Ritter, S J Schulz, D T Armstrong, Robert B GilchristAbstract:Oocyte-secreted factors are required for expansion of the mouse cumulus-oocyte complex (COC), which is necessary for ovulation. Members of the transforming growth factor-β (TGF-β) superfamily are prime candidates for the mouse cumulus expansion-enabling factor (CEEF), and we have recently determined that growth differentiation factor 9 (GDF9) alone is not the CEEF. This study was conducted to examine TGF-β superfamily processes regulating cumulus expansion. COCs were collected from eCG-primed mice and the oocyte microsurgically removed to generate oocytectomised (OOX) complexes. An established scoring system was used to measure FSH-induced cumulus expansion; 0 (no expansion) to +4 (maximum expansion). OOX complexes treated with FSH alone failed to expand (score: 0), whereas expansion was significantly (P 0.05) on the expansion of OOX complexes co-cultured with oocytes (score: 2.7 ± 0.2). This study provides evidence that activin is not the sole CEEF, but Signalling through the ALK4/5/7 pathway is indispensable for mouse cumulus expansion.
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247 molecular basis of oocyte Paracrine Signalling that promotes mouse granulosa cell proliferation
Reproduction Fertility and Development, 2004Co-Authors: Robert B Gilchrist, Lesley J Ritter, Samu Myllymaa, Noora Kaivooja, Olli Ritvos, F Amato, David G MottersheadAbstract:Oocytes regulate follicle growth and development by secreting Paracrine growth factors that act on granulosa cells (GC). We have recently determined that growth differentiation factor-9 (GDF-9) accounts for ~50% of the total mitogenic activity of oocytes, the remaining portion is as yet uncharacterised. This study was conducted to identify the receptor/Signalling system utilised by oocytes to promote GC proliferation. We used an established oocyte-secreted mitogen bioassay, where denuded oocytes are co-cultured with primed-mouse mural GC. In this system, oocytes, GDF-9, TGF-b1 and activin-A all promoted GC DNA synthesis in a dose-dependent manner, but bone-morphogenetic protein-6 (BMP-6) and BMP-7 did not. The type-II receptor for GDF-9 is BMPRII and using real-time RT-PCR, cumulus cells (CC) and mural GC were found to express equivalent levels of BMPRII mRNA. We tested the capacity of the receptor ectodomain (ECD) to neutralise oocyte-stimulated mural GC proliferation. The BMPRII ECD antagonised both oocyte and GDF-9 bioactivity in a dose-dependent manner, completely abolishing activity of both mitogens at 1 ug/mL. The BMPRII ECD did not antagonise TGF-β and partially antagonised activin-A bioactivity, demonstrating its specificity. The TGFβR-II ECD, activin R-II ECD and activin R-IIB ECD all failed to neutralise oocyte- or GDF-9-stimulated GC DNA synthesis, whereas they did antagonise the activity of their respective ligands. The BMPRII ECD also completely antagonised oocyte-stimulated CC DNA synthesis. Using this oocyte-factor bioassay with mural GC transfected with Smad luciferase reporter constructs, we found that oocytes, GDF-9 and TGF-β (but not BMP-6) activated the Smad2/3 pathway. Consistent with this, oocytes and GDF-9 led to phosphorylation of GC Smad2 molecules as detected by Western blot. Conversely the Smad1/5/8 pathway was activated by BMP-6, but not by GDF-9, TGF-β nor surprisingly by oocytes. This study provides evidence that BMPRII is a key receptor for transmitting the Paracrine actions of oocytes in GC. However, oocyte-secreted factors do not activate the BMP intracellular Signalling pathway but rather the TGF-β/activin intracellular pathway.
Denis Wirtz - One of the best experts on this subject based on the ideXlab platform.
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synergistic il 6 and il 8 Paracrine Signalling pathway infers a strategy to inhibit tumour cell migration
Nature Communications, 2017Co-Authors: Hasini Jayatilaka, Pranay Tyle, Jonathan J Chen, Minsuk Kwak, Julia A Ju, Pei Hsun Wu, Daniele M Gilkes, Denis WirtzAbstract:Following uncontrolled proliferation, a subset of primary tumour cells acquires additional traits/mutations to trigger phenotypic changes that enhance migration and are hypothesized to be the initiators of metastasis. This study reveals an adaptive mechanism that harnesses synergistic Paracrine Signalling via IL-6/8, which is amplified by cell proliferation and cell density, to directly promote cell migration. This effect occurs in metastatic human sarcoma and carcinoma cells- but not in normal or non-metastatic cancer cells-, and likely involves the downstream Signalling of WASF3 and Arp2/3. The transcriptional phenotype of high-density cells that emerges due to proliferation resembles that of low-density cells treated with a combination of IL-6/8. Simultaneous inhibition of IL-6/8 receptors decreases the expression of WASF3 and Arp2/3 in a mouse xenograft model and reduces metastasis. This study reveals a potential mechanism that promotes tumour cell migration and infers a strategy to decrease metastatic capacity of tumour cells.
Rita L C Carvalho - One of the best experts on this subject based on the ideXlab platform.
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defective Paracrine Signalling by tgfβ in yolk sac vasculature of endoglin mutant mice a paradigm for hereditary haemorrhagic telangiectasia
Development, 2004Co-Authors: Rita L C Carvalho, Leon Jonker, Mariejose Goumans, Jonas Larsson, Peter Bouwman, Stefan Karlsson, Peter Ten Dijke, Helen M Arthur, Christine L MummeryAbstract:Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant disorder in humans that is characterised by multisystemic vascular dyplasia and recurrent haemorrhage. Germline mutations in one of two different genes, endoglin or ALK1 can cause HHT. Both are members of the transforming growth factor (TGF) beta receptor family of proteins, and are expressed primarily on the surface of endothelial cells (ECs). Mice that lack endoglin or activin receptor like kinase (ALK) 1 die at mid-gestation as a result of defects in the yolk sac vasculature. Here, we have analyzed TGFbeta Signalling in yolk sacs from endoglin knockout mice and from mice with endothelial-specific deletion of the TGFbeta type II receptor (TbetaRII) or ALK5. We show that TGFbeta/ALK5 Signalling from endothelial cells to adjacent mesothelial cells is defective in these mice, as evidenced by reduced phosphorylation of Smad2. This results in the failure of vascular smooth muscle cells to differentiate and associate with endothelial cells so that blood vessels remain fragile and become dilated. Phosphorylation of Smad2 and differentiation of smooth muscle can be rescued by culture of the yolk sac with exogenous TGFbeta1. Our data show that disruption of TGFbeta Signalling in vascular endothelial cells results in reduced availability of TGFbeta1 protein to promote recruitment and differentiation of smooth muscle cells, and provide a possible explanation for weak vessel walls associated with HHT.
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defective Paracrine Signalling by tgfβ in yolk sac vasculature of endoglin mutant mice a paradigm for hereditary haemorrhagic telangiectasia
Development, 2004Co-Authors: Rita L C Carvalho, Leon Jonker, Mariejose Goumans, Jonas Larsson, Peter Bouwman, Stefan Karlsson, Peter Ten Dijke, Helen M Arthur, Christine L MummeryAbstract:Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant disorder in humans that is characterised by multisystemic vascular dyplasia and recurrent haemorrhage. Germline mutations in one of two different genes, endoglin or ALK1 can cause HHT. Both are members of the transforming growth factor (TGF) beta receptor family of proteins, and are expressed primarily on the surface of endothelial cells (ECs). Mice that lack endoglin or activin receptor like kinase (ALK) 1 die at mid-gestation as a result of defects in the yolk sac vasculature. Here, we have analyzed TGFbeta Signalling in yolk sacs from endoglin knockout mice and from mice with endothelial-specific deletion of the TGFbeta type II receptor (TbetaRII) or ALK5. We show that TGFbeta/ALK5 Signalling from endothelial cells to adjacent mesothelial cells is defective in these mice, as evidenced by reduced phosphorylation of Smad2. This results in the failure of vascular smooth muscle cells to differentiate and associate with endothelial cells so that blood vessels remain fragile and become dilated. Phosphorylation of Smad2 and differentiation of smooth muscle can be rescued by culture of the yolk sac with exogenous TGFbeta1. Our data show that disruption of TGFbeta Signalling in vascular endothelial cells results in reduced availability of TGFbeta1 protein to promote recruitment and differentiation of smooth muscle cells, and provide a possible explanation for weak vessel walls associated with HHT. (Less)
David G Mottershead - One of the best experts on this subject based on the ideXlab platform.
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molecular basis of oocyte Paracrine Signalling that promotes granulosa cell proliferation
Journal of Cell Science, 2006Co-Authors: Robert B Gilchrist, Lesley J Ritter, Samu Myllymaa, Noora Kaivooja, Rebecca Dragovic, Theresa E Hickey, Olli Ritvos, David G MottersheadAbstract:Oocytes regulate follicle growth by secreting Paracrine growth factors that act on neighbouring granulosa cells (GCs). Those factors identified to date are mainly members of the transforming growth factor-β (TGFβ) superfamily, but little is known about which specific receptor/Signalling system(s) they employ. This study was conducted to determine the requisite pathways utilised by oocytes to promote GC proliferation. We used an established oocyte-secreted mitogen bioassay, where denuded mouse oocytes are co-cultured with mural GCs. Oocytes, growth differentiation factor-9 (GDF9), TGFβ1 and activin-A all promoted GC DNA synthesis, but bone-morphogenetic protein 6 (BMP6) did not. Subsequently, we tested the capacity of various TGFβ superfamily receptor ectodomains (ECD) to neutralise oocyte- or specific growth factor-stimulated GC proliferation. The BMP type-II receptor (BMPR-II) ECD antagonised oocyte and GDF9 bioactivity dose-dependently, but had no or minimal effect on TGFβ1 and activin-A bioactivity, demonstrating its specificity. The TGFβR-II, activinR-IIA and activinR-IIB ECDs all failed to neutralise oocyte- or GDF9-stimulated GC DNA synthesis, whereas they did antagonise the activity of their respective native ligands. An activin receptor-like kinase (ALK) 4/5/7 inhibitor, SB431542, also antagonised both oocyte and GDF9 bioactivity in a dose-dependent manner. Consistent with these findings, oocytes, GDF9 and TGFβ1 all activated SMAD2/3 reporter constructs in transfected GC, and led to phosphorylation of SMAD2 proteins in treated cells. Surprisingly, oocytes did not activate the SMAD1/5/8 pathway in transfected GCs although exogenous BMP6 did. This study indicates that oocyte Paracrine factors primarily utilise a similar Signalling pathway first identified for GDF9 that employs an unusual combination of TGFβ superfamily receptors, the BMPR-II and a SMAD2/3 stimulatory ALK (4, 5 or 7), for transmitting their mitogenic actions in GC. This cell-Signalling pathway may also have relevance in the hypothalamic-pituitary axis and in germ-somatic cell interactions in the testis.
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247 molecular basis of oocyte Paracrine Signalling that promotes mouse granulosa cell proliferation
Reproduction Fertility and Development, 2004Co-Authors: Robert B Gilchrist, Lesley J Ritter, Samu Myllymaa, Noora Kaivooja, Olli Ritvos, F Amato, David G MottersheadAbstract:Oocytes regulate follicle growth and development by secreting Paracrine growth factors that act on granulosa cells (GC). We have recently determined that growth differentiation factor-9 (GDF-9) accounts for ~50% of the total mitogenic activity of oocytes, the remaining portion is as yet uncharacterised. This study was conducted to identify the receptor/Signalling system utilised by oocytes to promote GC proliferation. We used an established oocyte-secreted mitogen bioassay, where denuded oocytes are co-cultured with primed-mouse mural GC. In this system, oocytes, GDF-9, TGF-b1 and activin-A all promoted GC DNA synthesis in a dose-dependent manner, but bone-morphogenetic protein-6 (BMP-6) and BMP-7 did not. The type-II receptor for GDF-9 is BMPRII and using real-time RT-PCR, cumulus cells (CC) and mural GC were found to express equivalent levels of BMPRII mRNA. We tested the capacity of the receptor ectodomain (ECD) to neutralise oocyte-stimulated mural GC proliferation. The BMPRII ECD antagonised both oocyte and GDF-9 bioactivity in a dose-dependent manner, completely abolishing activity of both mitogens at 1 ug/mL. The BMPRII ECD did not antagonise TGF-β and partially antagonised activin-A bioactivity, demonstrating its specificity. The TGFβR-II ECD, activin R-II ECD and activin R-IIB ECD all failed to neutralise oocyte- or GDF-9-stimulated GC DNA synthesis, whereas they did antagonise the activity of their respective ligands. The BMPRII ECD also completely antagonised oocyte-stimulated CC DNA synthesis. Using this oocyte-factor bioassay with mural GC transfected with Smad luciferase reporter constructs, we found that oocytes, GDF-9 and TGF-β (but not BMP-6) activated the Smad2/3 pathway. Consistent with this, oocytes and GDF-9 led to phosphorylation of GC Smad2 molecules as detected by Western blot. Conversely the Smad1/5/8 pathway was activated by BMP-6, but not by GDF-9, TGF-β nor surprisingly by oocytes. This study provides evidence that BMPRII is a key receptor for transmitting the Paracrine actions of oocytes in GC. However, oocyte-secreted factors do not activate the BMP intracellular Signalling pathway but rather the TGF-β/activin intracellular pathway.
