TNF-alpha induces Lnk expression through PI3K-dependent signaling pathway in human umbilical vein endothelial cells.
BACKGROUND
A better understanding of activation process of endothelial cells (ECs) might reveal new ways of controlling inflammation. Adaptor proteins play crucial roles in ECs activation. Lnk is a newly discovered adaptor protein that has been proposed as a negative regulator of cytokine signaling. While limited information is available about Lnk in human ECs. This study was conducted to investigate the effect of TNF-alpha on Lnk expression in ECs and to identify the signal transduction pathway that is associated with Lnk regulation.


METHODS
Primary human umbilical vein endothelial cells (HUVECs) were cultured with designated doses of TNF-alpha and harvested at designated time points. Then Lnk mRNA and protein were detected using real-time polymerase chain reaction, immunoprecipitation and Western blot analysis, respectively.


RESULTS
The data demonstrated that Lnk mRNA and protein expression are induced significantly (P < 0.05) by TNF-alpha in a dose- and time-dependent manner. This inductive effect was abolished while phosphatidylinositol 3-kinase (PI3K) pathway was blocked by the PI3K inhibitor LY294002 and Wortmannin.


CONCLUSIONS
These results suggest that TNF-alpha induces Lnk expression through PI3K-dependent signaling pathway in HUVEC. This may indicate a role for this new adaptor protein in the regulation of TNF-alpha-induced ECs activation.
Wan
Meifang
M
Nanjing University School of Medicine, Nanjing, China.
Li
Yousheng
Y
Xue
Hua
H
Li
Qiurong
Q
Li
Jieshou
J
D048868:Adaptor Proteins, Signal Transducing; D000730:Androstadienes / Q000494:pharmacology; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011506:Proteins / Q000235:genetics*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism* / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D000077191:Wortmannin
D048868:Adaptor Proteins, Signal Transducing; D000730:Androstadienes; D002867:Chromones; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D011506:Proteins; D014409:Tumor Necrosis Factor-alpha; D000077191:Wortmannin; C490778:SH2B3 protein, human; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one