The neurotensin gene is a downstream target for Ras activation.

Evers, B. Mark; Zhou, Zhichao; Paul, C.; Li, Jing

doi:10.1172/jci117987

Cited by 47 publications

(23 citation statements)

References 60 publications

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“…Next, the binding of A. muciniphila to enterocytes grown for different periods (3 days, 8 days, and 21 days) was studied. The differentiation of Caco-2 cells starts within 3 to 4 days after confluence (20,21), and we used undifferentiated cells with confluent growth (3 days) and cells at two differentiation stages, grown for 8 and 21 days (i.e., 5 and 18 days after confluence, respectively). The HT-29 cell line does not differentiate, but we used the same growth times for comparison.…”

Section: Resultsmentioning

confidence: 99%

Akkermansia muciniphila Adheres to Enterocytes and Strengthens the Integrity of the Epithelial Cell Layer

Reunanen

Kainulainen

Huuskonen

et al. 2015

Appl Environ Microbiol

459

356

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e Akkermansia muciniphila is a Gram-negative mucin-degrading bacterium that resides in the gastrointestinal tracts of humans and animals. A. muciniphila has been linked with intestinal health and improved metabolic status in obese and type 2 diabetic subjects. Specifically, A. muciniphila has been shown to reduce high-fat-diet-induced endotoxemia, which develops as a result of an impaired gut barrier. Despite the accumulating evidence of the health-promoting effects of A. muciniphila, the mechanisms of interaction of the bacterium with the host have received little attention. In this study, we used several in vitro models to investigate the adhesion of A. muciniphila to the intestinal epithelium and its interaction with the host mucosa. We found that A. muciniphila adheres strongly to the Caco-2 and HT-29 human colonic cell lines but not to human colonic mucus. In addition, A. muciniphila showed binding to the extracellular matrix protein laminin but not to collagen I or IV, fibronectin, or fetuin. Importantly, A. muciniphila improved enterocyte monolayer integrity, as shown by a significant increase in the transepithelial electrical resistance (TER) of cocultures of Caco-2 cells with the bacterium. Further, A. muciniphila induced interleukin 8 (IL-8) production by enterocytes at cell concentrations 100-fold higher than those for Escherichia coli, suggesting a very low level of proinflammatory activity in the epithelium. In conclusion, our results demonstrate that A. muciniphila adheres to the intestinal epithelium and strengthens enterocyte monolayer integrity in vitro, suggesting an ability to fortify an impaired gut barrier. These results support earlier associative in vivo studies and provide insights into the interaction of A. muciniphila with the host.

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Section: Resultsmentioning

confidence: 99%

Akkermansia muciniphila Adheres to Enterocytes and Strengthens the Integrity of the Epithelial Cell Layer

Reunanen

Kainulainen

Huuskonen

et al. 2015

Appl Environ Microbiol

459

356

View full text Add to dashboard Cite

show abstract

“…Total RNA (40 g) was run in 1.2% agarose/formaldehyde gels and transferred to supported nitrocellulose as previously described (40). Membranes were hybridized to a random-primed 32 P-labeled TRAIL cDNA probe overnight at 43°C and then washed two times at room temperature with 2ϫ SSC and 0.1% SDS and two times at 43°C for 15 min with 0.1ϫ SSC and 0.1% SDS.…”

Section: Methodsmentioning

confidence: 99%

Regulation of TRAIL Expression by the Phosphatidylinositol 3-Kinase/Akt/GSK-3 Pathway in Human Colon Cancer Cells

Wang

Hernandez

et al. 2002

Journal of Biological Chemistry

104

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“…The expression vectors for IKKb and IKKb-KM (K44A) were generous gifts from Dr Hiroyasu Nakano (Juntendo University, Tokyo, Japan) (Nakano et al, 1998). Raf-C4, Raf-C4M17, Ras-N17 and pZIP-neo(x) plasmids were described previously (Evers et al, 1995). SW480 cells were seeded in 24-well plates (0.3 Â 10 6 cells/well) 1 day prior to transfection.…”

Section: Transient Transfection Luciferase Assaysmentioning

confidence: 99%

Regulation of phorbol ester-mediated TRAF1 induction in human colon cancer cells through a PKC/RAF/ERK/NF-κB-dependent pathway

Wang

et al. 2004

Oncogene

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Tumor necrosis factor (TNF) receptor-associated factors (TRAFs) are cytoplasmic adapter proteins that link a wide variety of cell surface receptors to the apoptotic signaling cascade. The purpose of this study was to delineate the signaling pathways and TRAF1 promoter elements responsible for phorbol ester-mediated TRAF1 induction in human colon cancers. Here, we found that the PKC activators, phorbol 12-myristate 13-acetate (PMA) and bryostatin I, induced TRAF1 mRNA expression; pretreatment with actinomycin D blocked PMA-mediated TRAF1 expression suggesting induction at the transcriptional level. In contrast, expression of other TRAFs (TRAF2, 3 and 4) was minimally altered by PMA. Various PKC isoform-selective inhibitors blocked PMAmediated TRAF1 mRNA and promoter stimulation; rottlerin, a selective PKCd inhibitor, had no effect suggesting that Ca 2 þ -dependent PKC isoforms (e.g., PKCa and bI) play a role in TRAF1 regulation. In addition, the MEK/ERK inhibitors, PD98059 and UO126, suppressed PMA-stimulated TRAF1 promoter activity indicating a role for ERK in TRAF1 induction. Moreover, cotransfection of a dominant-negative Raf-1 (Raf-C4) significantly reduced PMA-stimulated TRAF1 promoter activity whereas transfection of dominantnegative Ras or treatment with Ras inhibitors had minimal to no effect on TRAF1 induction suggesting dependence on Raf, but not Ras, activation. Finally, site-specific mutagenesis of functional NF-jB sites (particularly the most proximal site) in the TRAF1 promoter significantly decreased PMA-mediated promoter activity. In conclusion, our results demonstrate selective induction of TRAF1 in human colon cancer cells through a Ca 2 þ -dependent PKC/Raf-1/ERK/NF-jB-dependent pathway.

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The neurotensin gene is a downstream target for Ras activation.

Abstract: Introduction

Cited by 47 publications

References 60 publications

Akkermansia muciniphila Adheres to Enterocytes and Strengthens the Integrity of the Epithelial Cell Layer

Akkermansia muciniphila Adheres to Enterocytes and Strengthens the Integrity of the Epithelial Cell Layer

Regulation of TRAIL Expression by the Phosphatidylinositol 3-Kinase/Akt/GSK-3 Pathway in Human Colon Cancer Cells

Regulation of phorbol ester-mediated TRAF1 induction in human colon cancer cells through a PKC/RAF/ERK/NF-κB-dependent pathway

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