Lookup NU author(s): Dr Neil Foster,
Professor Philip Preshaw,
Dr John Taylor
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Vasoactive intestinal peptide (VIP) is an immunoregulatory peptide, which inhibits LPS-induced cytokine secretion in myeloid cells and has beneficial effects in animal models of inflammatory diseases. We show for the first time that VIP decreases LPS-induced up-regulation of TLR2 and TLR4 by human monocytic THP1 cells and peripheral blood monocytes (PBM). VIP inhibited upregulation of TLR4 expression in THP1 cells in response to LPS from Escherichia coli or the periodontal pathogen Porphyromonas gingivalis within 6 h poststimulation but had less of an effect on TLR2. After 24 h, P. gingivalis LPS-stimulated monocytic THP1 cells to differentiate into macrophages, which predominantly expressed TLR2, and E. coli LPS-stimulated THP1 differentiation to predominantly TLR4-expressing macrophages. VIP decreased monocyte differentiation to macrophages induced by LPS from either species and also reduced overall TLR2 and TLR4 expression in these cells. VIP had a similar effect on human PBM. The transcription factor PU.1 regulates TLR expression and has a central role in myeloid cell differentiation. VIP inhibited the nuclear translocation of PU.1 in LPS-stimulated THP-1 monocytes. VIP also inhibited the expression of the MCSF receptor, which is regulated by PU.1. In summary, VIP inhibited LPS-induced differentiation of monocytes with a concomitant reduction in TLR2 and TLR4 expression. Although there was differential induction of TLR expression by LPS from P. gingivalis and E. coli, VIP inhibited the action of both of these LPS types on monocytes. The mechanism of action of VIP on monocyte differentiation may be via inhibition of the transcription factor PU.1. © Society for Leukocyte Biology.
Author(s): Foster N, Lea SR, Preshaw PM, Taylor JJ
Publication type: Article
Publication status: Published
Journal: Journal of Leukocyte Biology
ISSN (print): 0741-5400
ISSN (electronic): 1938-3673
Publisher: Federation of American Societies for Experimental Biology
PubMed id: 16973891
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