Role of MyD88 in Phosphatidylinositol 3-Kinase Activation by Flagellin/Toll-like Receptor 5 Engagement in Colonic Epithelial Cells

ABSTRACT The role intestinal epithelial cells play in the pathogenesis of amebic colitis is poorly understood. Herein, we demonstrate that secreted and soluble ameba (Entamoeba histolytica) proteins (SAP) induce expression of the chemoattractant monocyte chemotactic protein (MCP) in the colonic epithelial cell lines Caco-2, T84, and LS174T. MCP-1 mRNA induction was both dose and time dependent, with peak induction occurring at 8 h and with 100 μg/ml of SAP. Significant increase in MCP-1 protein expression was observed after 12 h. SAP failed to activate any of the mitogen-activated protein kinase pathways or IκB kinase activity. Moreover, inhibiting the classical pathway of NF-κB activation did not affect SAP-induced MCP-1 expression. Instead, we find that SAP-induced MCP-1 expression is dependent on posttranslational modification of the NFκB p65 subunit. SAP induced phosphorylation of p65 and enhanced NF-κB transcriptional activity, which are phosphatidylinositol 3-kinase (PI3 kinase) dependent. Treatment with PI3 kinase inhibitor LY290004 significantly abrogated the activation of Akt, p65, and MCP-1 mRNA induction. We conclude that colonic epithelial cells play a role in the initiation of inflammation by secreting chemokines in response to soluble ameba components.

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Phosphatidylinositol 3-kinase activity is important for progesterone-induced Xenopus oocyte maturation.

Molecular and Cellular Biology ◽

10.1128/mcb.13.11.6661 ◽

1993 ◽

Vol 13 (11) ◽

pp. 6661-6666 ◽

Cited By ~ 44

Author(s):

A J Muslin ◽

A Klippel ◽

L T Williams

Keyword(s):

Oocyte Maturation ◽

Kinase Activity ◽

Sh2 Domain ◽

Pi3 Kinase ◽

Meiotic Maturation ◽

Xenopus Laevis Oocytes ◽

Phosphatidylinositol 3 Kinase ◽

Kinase Activation ◽

Phosphatidylinositol 3

In somatic cells, phosphatidylinositol 3-kinase (PI3 kinase) is a critical intermediary in growth factor-induced mitogenesis. We have examined the role of this enzyme in meiotic maturation of Xenopus laevis oocytes. PI3 kinase activity was present in immunoprecipitates of the p85 subunit of PI3 kinase from immature oocytes and markedly increased following progesterone stimulation. Injection of bacterially expressed protein corresponding to the C-terminal SH2 domain of p85 (SH2-C) inhibited progesterone-induced PI3 kinase activation and meiotic maturation. Injection of protein corresponding to the N-terminal SH2 domain or the SH3 domain of p85 did not inhibit PI3 kinase activation or maturation. SH2-C did not inhibit oocyte maturation induced by c-mos RNA injection. In addition, radiolabelled SH2-C was used to probe oocyte lysates, revealing that a novel 200-kDa protein bound to SH2-C. This protein may be an important mediator of progesterone-induced lipid metabolism in oocytes.

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Role of Phosphatidylinositol 3-Kinase Activation on Insulin Action and Its Alteration in Diabetic Conditions

Biological and Pharmaceutical Bulletin ◽

10.1248/bpb.30.1610 ◽

2007 ◽

Vol 30 (9) ◽

pp. 1610-1616 ◽

Cited By ~ 40

Author(s):

Tomoichiro Asano ◽

Midori Fujishiro ◽

Akifumi Kushiyama ◽

Yusuke Nakatsu ◽

Masayasu Yoneda ◽

...

Keyword(s):

Insulin Action ◽

Phosphatidylinositol 3 Kinase ◽

Kinase Activation ◽

Phosphatidylinositol 3

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Role of Gab proteins in phosphatidylinositol 3-kinase activation by thrombopoietin (Tpo)

Oncogene ◽

10.1038/sj.onc.1204317 ◽

2001 ◽

Vol 20 (18) ◽

pp. 2197-2204 ◽

Cited By ~ 27

Author(s):

Didier Bouscary ◽

Carinne Lecoq-Lafon ◽

Stany Chrétien ◽

Simona Zompi ◽

Serge Fichelson ◽

...

Keyword(s):

Phosphatidylinositol 3 Kinase ◽

Kinase Activation ◽

Phosphatidylinositol 3

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Tumour necrosis factor-a induced cyclooxygenase 2 expression is phosphatidylinositol 3-kinase dependent in colonic epithelial cells

Gastroenterology ◽

10.1016/s0016-5085(00)84898-2 ◽

2000 ◽

Vol 118 (4) ◽

pp. A691

Author(s):

Sean A. Weaver ◽

Karen L. Wright ◽

Duncan A. Robertson ◽

Stephen G. Ward

Keyword(s):

Epithelial Cells ◽

Tumour Necrosis Factor ◽

Tumour Necrosis ◽

Cyclooxygenase 2 ◽

Phosphatidylinositol 3 Kinase ◽

Colonic Epithelial Cells ◽

Necrosis Factor ◽

Phosphatidylinositol 3

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The p110αand p110βIsoforms of Class I Phosphatidylinositol 3-Kinase Are Involved in Toll-Like Receptor 5 Signaling in Epithelial Cells

Mediators of Inflammation ◽

10.1155/2010/652098 ◽

2010 ◽

Vol 2010 ◽

pp. 1-12 ◽

Cited By ~ 4

Author(s):

Sabine M. Ivison ◽

Mohammed A. S. Khan ◽

Nicholas R. Graham ◽

Leila A. Shobab ◽

Yu Yao ◽

...

Keyword(s):

Mammalian Cells ◽

P38 Map Kinase ◽

Carcinoma Cells ◽

Model Systems ◽

Toll Like Receptor ◽

Phosphatidylinositol 3 Kinase ◽

Proinflammatory Response ◽

Colon Carcinoma Cells ◽

Toll Like Receptor 5 ◽

Phosphatidylinositol 3

Background. Bacterial flagellin triggers inflammation in mammalian cells via Toll-like receptor (TLR) 5. Release of the chemokine IL-8 in response to flagellin involves NF-κB, p38 MAP kinase, and phosphatidylinositol 3-kinase (PI3K). However, PI3K has been reported to be either pro- or anti-inflammatory in different model systems. We hypothesized that this could be due to different activities of the p110αandβisoforms of PI3K.Results. PI3K and Akt were rapidly activated in Caco-2 colon carcinoma cells by flagellin. Using a plasmid-based shRNA delivery system and novel p110 isoform-specific inhibitors, we found that flagellin-induced IL-8 production was dependent on both p110αand p110β. However in the mouse, inhibition of p110βbut not p110αreduced the increase of serum IL-6 levels induced by intraperitoneal injection of flagellin.Conclusions. These data demonstrate that the p110αandβisoforms of class IA PI3K are both required for the proinflammatory response to flagellin.

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