Oxytocin antagonism prevents pregnancy-associated aortic dissection in a mouse model of Marfan syndrome

Women with Marfan syndrome (MFS) are at high risk for pregnancy-associated aortic dissection. Pathogenic models that singularly invoke hemodynamic stress are difficult to reconcile with predominant postnatal occurrence of aortic tear, often occurring weeks to months after delivery. In consideration of events that peak at term, are sustained after delivery, and might synergize with previously defined signaling pathways implicated in aneurysm progression, we examined the hormone oxytocin, which initiates uterine contraction and milk letdown for the duration of lactation through phosphorylation of extracellular signal–regulated kinase (ERK). In a mouse model of MFS that shows highly penetrant postnatal aortic dissection, risk was strongly attenuated by preventing lactation or use of an oxytocin receptor antagonist. Survival correlated inversely with the extent of ERK activation in the aortic wall, and strong protection was observed upon attenuation of ERK phosphorylation using an inhibitor of ERK kinase (MEK) or the U.S. Food and Drug Administration–approved medication hydralazine, offering potential therapeutic strategies for pregnancy-associated vascular catastrophe in the setting of MFS.

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Influence of ERK activation on decreased chemotaxis of mature human cord blood monocyte–derived dendritic cells to CCL19 and CXCL12

Blood ◽

10.1182/blood-2006-04-014753 ◽

2006 ◽

Vol 109 (8) ◽

pp. 3173-3176 ◽

Cited By ~ 12

Author(s):

Geling Li ◽

Sunanda Basu ◽

Myung-Kwan Han ◽

Young-June Kim ◽

Hal E. Broxmeyer

Keyword(s):

Dendritic Cells ◽

Cord Blood ◽

Human Cord Blood ◽

Erk Activation ◽

Extracellular Signal Regulated Kinase ◽

Graft Versus Host ◽

Erk Phosphorylation ◽

Extracellular Signal ◽

Insight Into ◽

Dc Maturation

Abstract Dendritic cells (DCs) are important regulators in graft-versus-host disease (GVHD). To gain insight into cord blood (CB) DC immunology, we compared chemotactic responses of mature monocyte-derived DCs and maturation agent lipopolysaccharide (LPS)–induced signaling between CB and adult blood (AB). Mature CB DCs expressed reduced CCR7, but increased CXCR4. This was associated with reduced migratory efficiency toward both CCR7 ligand CCL19 and CXCR4 ligand CXCL12. LPS induced higher extracellular signal-regulated kinase (ERK) phosphorylation in CB than in AB DCs. Specific inhibition of ERK during CB DC maturation enhanced LPS-induced up-regulation of CCR7 and CXCR4 on CB DCs and their chemotaxis toward CCL19 and CXCL12, to a level similar to that of mature AB DCs. Overall, monocyte-derived CB DCs responded to LPS with stronger and sustained ERK activation, which negatively correlated with LPS-induced up-regulation of CCR7 and CXCR4 on CB DCs and their migratory responses. These findings may have potential relevance to better understanding DC function in CB transplantation.

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ShcA Mediates the Dominant Pathway to Extracellular Signal-Regulated Kinase Activation during Early Thymic Development

Molecular and Cellular Biology ◽

10.1128/mcb.00988-06 ◽

2006 ◽

Vol 26 (23) ◽

pp. 9035-9044 ◽

Cited By ~ 6

Author(s):

Paul Trampont ◽

Li Zhang ◽

Kodi S. Ravichandran

Keyword(s):

Ex Vivo ◽

Dominant Role ◽

Cell Receptor ◽

Thymocyte Development ◽

Erk Activation ◽

Thymic Development ◽

Extracellular Signal Regulated Kinase ◽

Erk Phosphorylation ◽

Extracellular Signal

ABSTRACT During thymic development, the β selection checkpoint is regulated by pre-T-cell receptor-initiated signals. Progression through this checkpoint is influenced by phosphorylation and activation of the serine/threonine kinases extracellular signal-regulated kinase 1 (ERK1) and ERK2, but the in vivo relevance of specific upstream players leading to ERK activation is not known. Here, using mice with a conditional loss of the shc1 gene or expressing mutants of ShcA, we demonstrate that the adapter protein ShcA is responsible for up to 70% of ERK activation in double-negative (DN) thymocytes in vivo and ex vivo. We also identify two specific tyrosines on ShcA that promote ERK phosphorylation in vivo, and mice expressing ShcA with mutations of these tyrosines show impaired DN thymocyte development. This work provides the first in vivo demonstration of the relative requirement of upstream adapters in controlling ERK activation during β selection and suggests a dominant role for ShcA.

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The Extracellular Signal-regulated Kinase–Mitogen-activated Protein Kinase Pathway Phosphorylates and Targets Cdc25A for SCFβ-TrCP-dependent Degradation for Cell Cycle Arrest

Molecular Biology of the Cell ◽

10.1091/mbc.e09-01-0008 ◽

2009 ◽

Vol 20 (8) ◽

pp. 2186-2195 ◽

Cited By ~ 28

Author(s):

Michitaka Isoda ◽

Yoshinori Kanemori ◽

Nobushige Nakajo ◽

Sanae Uchida ◽

Katsumi Yamashita ◽

...

Keyword(s):

Cell Cycle ◽

Cell Cycle Arrest ◽

Genotoxic Stress ◽

Mitogen Activated Protein Kinase ◽

Erk Pathway ◽

Erk Activation ◽

Extracellular Signal Regulated Kinase ◽

Cycle Arrest ◽

Erk Phosphorylation ◽

Extracellular Signal

The extracellular signal-regulated kinase (ERK) pathway is generally mitogenic, but, upon strong activation, it causes cell cycle arrest by a not-yet fully understood mechanism. In response to genotoxic stress, Chk1 hyperphosphorylates Cdc25A, a positive cell cycle regulator, and targets it for Skp1/Cullin1/F-box protein (SCF)β-TrCP ubiquitin ligase-dependent degradation, thereby leading to cell cycle arrest. Here, we show that strong ERK activation can also phosphorylate and target Cdc25A for SCFβ-TrCP-dependent degradation. When strongly activated in Xenopus eggs, the ERK pathway induces prominent phosphorylation and SCFβ-TrCP-dependent degradation of Cdc25A. p90rsk, the kinase downstream of ERK, directly phosphorylates Cdc25A on multiple sites, which, interestingly, overlap with Chk1 phosphorylation sites. Furthermore, ERK itself phosphorylates Cdc25A on multiple sites, a major site of which apparently is phosphorylated by cyclin-dependent kinase (Cdk) in Chk1-induced degradation. p90rsk phosphorylation and ERK phosphorylation contribute, roughly equally and additively, to the degradation of Cdc25A, and such Cdc25A degradation occurs during oocyte maturation in which the endogenous ERK pathway is fully activated. Finally, and importantly, ERK-induced Cdc25A degradation can elicit cell cycle arrest in early embryos. These results suggest that strong ERK activation can target Cdc25A for degradation in a manner similar to, but independent of, Chk1 for cell cycle arrest.

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Ribosomal S6 kinase-1 modulates interleukin-1β-induced persistent activation of NF-κB through phosphorylation of IκBβ

AJP Cell Physiology ◽

10.1152/ajpcell.00552.2005 ◽

2006 ◽

Vol 291 (6) ◽

pp. C1336-C1345 ◽

Cited By ~ 36

Author(s):

Shanqin Xu ◽

Hossein Bayat ◽

Xiuyun Hou ◽

Bingbing Jiang

Keyword(s):

Nuclear Translocation ◽

Erk Signaling ◽

Signaling Cascade ◽

S6 Kinase ◽

Small Interference Rna ◽

Erk Activation ◽

Extracellular Signal Regulated Kinase ◽

Erk Phosphorylation ◽

Extracellular Signal ◽

Ribosomal S6 Kinase

Activation of NF-κB requires the phosphorylation and degradation of its associated inhibitory proteins, IκB. Previously, we reported that the extracellular signal-regulated kinase (ERK) is required for IL-1β to induce persistent activation of NF-κB in cultured rat vascular smooth muscle cells (VSMCs). The present study examined the mechanism by which the ERK signaling cascade modulates the duration of NF-κB activation. In cultured rat VSMCs, IL-1β activated ERK and induced degradation of both IκBα and IκBβ, which was associated with nuclear translocation of both ribosomal S6 kinase (RSK)1 and NF-κB p65. RSK1, a downstream kinase of ERK, was associated with an IκBβ/NF-κB complex, which was independent of the phosphorylation status of RSK1. Treatment of VSMCs with IL-1β decreased IκBβ in the RSK1/IκBβ/NF-κB complex, an effect that was attenuated by inhibition of ERK activation. Knockdown of RSK1 by small interference RNA attenuated the IL-1β-induced IκBβ decrease without influencing ether ERK phosphorylation or the earlier IκBα degradation. By using recombinant wild-type and mutant IκBβ proteins, both active ERK2 and RSK1 were found to directly phosphorylate IκBβ, but only active RSK1 phosphorylated IκBβ on Ser19 and Ser23, two sites known to mediate the subsequent ubiquitination and degradation. In conclusion, in the ERK signaling cascade, RSK1 is a key component that directly phosphorylates IκBβ and contributes to the persistent activation of NF-κB by IL-1β.

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Gonadotropin-Releasing Hormone Pulse Frequency-Dependent Activation of Extracellular Signal-Regulated Kinase Pathways in Perifused LβT2 Cells

Endocrinology ◽

10.1210/en.2004-1317 ◽

2005 ◽

Vol 146 (12) ◽

pp. 5503-5513 ◽

Cited By ~ 83

Author(s):

Haruhiko Kanasaki ◽

Gregoy Y. Bedecarrats ◽

Kyung-Yoon Kam ◽

Shuyun Xu ◽

Ursula B. Kaiser

Keyword(s):

Pulse Frequency ◽

Frequency Dependent ◽

Erk Activation ◽

Extracellular Signal Regulated Kinase ◽

Erk Phosphorylation ◽

Extracellular Signal ◽

Gnrh Release ◽

The Difference ◽

Stimulation Of

The pattern of GnRH release is associated with differential synthesis and release of LH and FSH. Using a perifusion system, we previously reported that stimulation of the LβT2 cell line with varying GnRH pulse frequencies resulted in differential stimulation of LHβ and FSHβ gene transcription, analogous to previous observations in primary gonadotropes. In the present study, we investigated the patterns of MAPK activation by GnRH and the role of MAPK in mediating the frequency-dependent effects. In static culture, ERK activation in LβT2 cells stimulated with continuous GnRH (10 nm) was maximal by 10 min and persisted for up to 6 h, with a return to basal levels by 20 h. In contrast, stimulation with continuous GnRH (10 nm) in perifused cells resulted in a more sustained activation of ERK. To investigate the effects of GnRH pulse frequency on ERK activation, perifused LβT2 cells were stimulated with pulsatile GnRH at a frequency of one pulse every 30 min or one pulse every 2 h for 20 h (10 nm, 5 min/pulse). After the final GnRH pulse, cells were lysed at frequent intervals and levels of ERK phosphorylation were measured. Under high-frequency conditions, ERK activation was maximal 10 min after the GnRH pulse and returned to baseline levels by 20 min. In contrast, under lower GnRH pulse frequency conditions, ERK activation occurred more rapidly and activation was more sustained, with a slower rate of ERK dephosphorylation. These changes resulted in different levels of nuclear phosphorylated ERK. Blockade of ERK activation abolished GnRH-dependent activation of LHβ and FSHβ transcription at both high and low pulse frequencies. These results demonstrate that in perifused LβT2 cells, distinct patterns of ERK activation/inactivation are regulated by GnRH pulse frequency, and the difference in ERK activation may be important for GnRH pulse frequency-dependent differential stimulation of LHβ and FSHβ gene expression.

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Autocrine Extracellular Signal-regulated Kinase (ERK) Activation in Normal Human Keratinocytes: Metalloproteinase-mediated Release of Amphiregulin Triggers Signaling from ErbB1 to ERK

Molecular Biology of the Cell ◽

10.1091/mbc.e04-03-0233 ◽

2004 ◽

Vol 15 (9) ◽

pp. 4299-4309 ◽

Cited By ~ 40

Author(s):

Sanjay Kansra ◽

Stefan W. Stoll ◽

Jessica L. Johnson ◽

James T. Elder

Keyword(s):

Growth Factor ◽

Neutralizing Antibodies ◽

Human Keratinocytes ◽

Erk Activation ◽

Extracellular Signal Regulated Kinase ◽

Erk Phosphorylation ◽

Extracellular Signal ◽

Normal Human Keratinocytes ◽

Metalloproteinase Inhibitors ◽

Normal Human

ErbB signaling through extracellular signal-regulated kinase (ERK) has been implicated in regulating the expression of ErbB ligands in hyperproliferative skin disorders and wound healing. Here, we characterize the process of autocrine ERK activation in cultured normal human keratinocytes (NHKs) subjected to growth factor (GF) deprivation. Basal ERK phosphorylation was lower after 48 h than after 24 h of GF deprivation, and lowest at 30–60 min after an additional medium change. ERK phosphorylation was markedly increased by low concentrations of epidermal growth factor (EGF) (0.2–1 ng/ml) that provoked only a limited increase in ErbB1 tyrosine phosphorylation and internalization. Basal ErbB tyrosine phosphorylation and ERK phosphorylation were inhibited by two different ErbB receptor tyrosine kinase inhibitors, by the ErbB1-specific neutralizing monoclonal antibody 225 IgG, by two different metalloproteinase inhibitors, and by neutralizing antibodies against amphiregulin (AR). In contrast, these responses were unaffected by neutralizing antibodies against other ErbB1 ligands or the ErbB2 inhibitors geldanamycin and AG825. The time course of autocrine ERK phosphorylation correlated with the appearance of soluble AR, and two different metalloproteinase inhibitors blocked AR release. These results define an amphiregulin- and ErbB1-dependent mechanism by which autocrine ERK activation is maintained in NHKs, even when ErbB1 autophosphorylation and internalization are limited.

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Preventive Effects of a Kampo Medicine, Kakkonto, on Inflammatory Responses via the Suppression of Extracellular Signal-Regulated Kinase Phosphorylation in Lipopolysaccharide-Treated Human Gingival Fibroblasts

ISRN Pharmacology ◽

10.1155/2014/784019 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 7

Author(s):

Hiroyuki Kitamura ◽

Hiroko Urano ◽

Toshiaki Ara

Keyword(s):

Periodontal Disease ◽

Inflammatory Responses ◽

Human Gingival Fibroblasts ◽

Kampo Medicine ◽

Prostaglandin E ◽

Gingival Fibroblasts ◽

Extracellular Signal Regulated Kinase ◽

Erk Phosphorylation ◽

Extracellular Signal ◽

Cox 2

Periodontal disease is accompanied by inflammation of the gingiva and destruction of periodontal tissues, leading to alveolar bone loss in severe clinical cases. The chemical mediator prostaglandin E2 (PGE2) and cytokines such as interleukin- (IL-)6 and IL-8 have been known to play important roles in inflammatory responses and tissue degradation. In the present study, we investigated the effects of a kampo medicine, kakkonto (TJ-1), on the production of prostaglandin E2 (PGE2), IL-6, and IL-8 by human gingival fibroblasts (HGFs) treated with lipopolysaccharide (LPS) from Porphyromonas gingivalis. Kakkonto concentration dependently suppressed LPS-induced PGE2 production but did not alter basal PGE2 levels. In contrast, kakkonto significantly increased LPS-induced IL-6 and IL-8 production. Kakkonto decreased cyclooxygenase- (COX-)1 activity to approximately 70% at 1 mg/mL but did not affect COX-2 activity. Kakkonto did not affect cytoplasmic phospholipase A2 (cPLA2), annexin1, or LPS-induced COX-2 expression. Kakkonto suppressed LPS-induced extracellular signal-regulated kinase (ERK) phosphorylation, which is known to lead to ERK activation and cPLA2 phosphorylation. These results suggest that kakkonto decreased PGE2 production by inhibition of ERK phosphorylation which leads to inhibition of cPLA2 phosphorylation and its activation. Therefore, kakkonto may be useful to improve gingival inflammation in periodontal disease.

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Tangeretin inhibits extracellular-signal-regulated kinase (ERK) phosphorylation

FEBS Letters ◽

10.1016/j.febslet.2004.10.114 ◽

2005 ◽

Vol 579 (7) ◽

pp. 1665-1669 ◽

Cited By ~ 26

Author(s):

Séverine Van Slambrouck ◽

Virinder S. Parmar ◽

Sunil K. Sharma ◽

Bart De Bondt ◽

Fleur Foré ◽

...

Keyword(s):

Extracellular Signal Regulated Kinase ◽

Erk Phosphorylation ◽

Extracellular Signal

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Renin and prorenin have no direct effect on aldosterone synthesis in the human adrenocortical cell lines H295R and HAC15

Journal of the Renin-Angiotensin-Aldosterone System ◽

10.1177/1470320312438792 ◽

2012 ◽

Vol 13 (3) ◽

pp. 360-366 ◽

Cited By ~ 9

Author(s):

Pieter M Jansen ◽

Johannes Hofland ◽

Anton H van den Meiracker ◽

Frank H de Jong ◽

AH Jan Danser

Keyword(s):

Angiotensin Ii ◽

Cell Lines ◽

Renin Angiotensin System ◽

Adrenocortical Cell ◽

Transgenic Rats ◽

Angiotensin System ◽

Extracellular Signal Regulated Kinase ◽

Erk Phosphorylation ◽

Extracellular Signal ◽

Aldosterone Production

Introduction: Transgenic rats expressing the human (pro)renin receptor (h(P)RR) have elevated plasma aldosterone levels despite unaltered levels, in plasma and adrenal, of renin and angiotensin II. Materials and methods: To investigate whether renin/prorenin–(P)RR interaction underlies these elevated aldosterone levels, the effect of (pro)renin on steroidogenesis was compared with that of angiotensin II in two (P)RR-expressing human adrenocortical cell lines, H295R and HAC15. Angiotensin II rapidly induced extracellular signal-regulated kinase (ERK) phosphorylation and increased the expression of STAR, CYP21A2, CYP11B2, and CYP17A1 at 6 and 24 hours, whereas the expression of CYP11A1 and HSD3B2 remained unaltered. Incubation with renin or prorenin at nanomolar concentrations had no effect on the expression of any of the steroidogenic enzymes tested, nor resulted in ERK phosphorylation. Angiotensin II, but not renin or prorenin, induced aldosterone production. Conclusion: Although the (P)RR is present in adrenocortical cells, renin and prorenin do not elicit ERK phosphorylation nor directly affect steroid production via this receptor at nanomolar concentrations. Thus, direct (pro)renin–(P)RR interaction is unlikely to contribute to the elevated aldosterone levels in human (P)RR transgenic rats. This conclusion also implies that the aldosterone rise that often occurs during prolonged renin–angiotensin system blockade is rather due to the angiotensin II ‘escape’ during such blockade.

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