Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Endod. 2014 Jan;40(1):69-75. doi: 10.1016/j.joen.2013.09.011. Epub 2013 Oct 22.

Lipopolysaccharide enhances Wnt5a expression through toll-like receptor 4, myeloid differentiating factor 88, phosphatidylinositol 3-OH kinase/AKT and nuclear factor kappa B pathways in human dental pulp stem cells.

Author information

  • 1Department of Operative Dentistry, School of Dentistry, The Fourth Military Medical University, Xi'an, PR China. Electronic address: hewenxi@fmmu.edu.cn.
  • 2Department of Operative Dentistry, School of Dentistry, The Fourth Military Medical University, Xi'an, PR China.
  • 3Department of Oral Biology, School of Dentistry, University of Birmingham, Birmingham, United Kingdom.
  • 4Department of Operative Dentistry, School of Dentistry, The Fourth Military Medical University, Xi'an, PR China. Electronic address: hefmmu@aliyun.com.

Abstract

INTRODUCTION:

Lipopolysaccharide (LPS) has been implicated in mesenchymal stem cell differentiation processes. Wnt5a, one of the "non-canonical" Wnt family members, is important in signaling stem cell differentiation and in the inflammatory responses of immune cells. Here we studied whether LPS can regulate the expression of Wnt5a in human dental pulp stem cells (hDPSCs) and investigated the intracellular signaling pathways activated by LPS.

METHODS:

Wnt5a mRNA and protein expression changes in hDPSCs were investigated by real-time polymerase chain reaction analysis and enzyme-linked immunosorbent assay. In addition, real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and luciferase activity assays were used to determine whether toll-like receptor 4 (TLR4), myeloid differentiating factor 88 (MyD88), nuclear factor kappa B (NF-kB), or the phosphatidylinositol 3-OH kinase (PI3K)/AKT pathways are involved in LPS-induced Wnt5a expression. The activation of PI3K and AKT in hDPSCs was measured by Western blot analysis.

RESULTS:

Wnt5a mRNA and protein expression was rapidly increased in response to LPS in a time- and dose-dependent manner. LPS-induced Wnt5a expression was effectively attenuated by administration of a TLR4 neutralizing antibody, MyD88 inhibitory peptide, PI3-kinase inhibitors (LY294002 and wortmannin), an AKT inhibitor, or NF-κB inhibitor (pyrrolidine dithiocarbamate), IκBa phosphorylation inhibitor (Bay 117082), or IκB protease inhibitor (L-1-tosylamido-2-phenylethyl chloromethyl ketone). Treatment of hDPSCs with LPS activated PI3-kinase (p85) and AKT signaling in a time-dependent manner. Moreover, LPS-mediated increases in κB-luciferase activity were diminished by the overexpression of dominant negative mutants of TLR4, MyD88, p85, AKT, and IκBa.

CONCLUSIONS:

These results demonstrated that LPS-induced Wnt5a expression was mediated through the TLR4/MyD88/PI3-kinase/AKT pathway, which then initiated NF-κB activation in hDPSCs.

Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

KEYWORDS:

Dental pulp stem cells; LPS; NF-kappaB; PI3K/AKT; TLR4; Wnt5a

PMID:
24331994
[PubMed - in process]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk