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TP508, a thrombin‐derived peptide, modulates TLR‐4 dependent cytokine expression in differentiated THP‐1 cells
Author(s) -
Rousseau Emma,
Smoke Chris,
Zepp Jarod,
Dinarello Charles A.,
Sheller Michael R.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.lb20
Subject(s) - cytokine , thrombin , integrin , receptor , chemistry , tlr4 , thp1 cell line , lipopolysaccharide , tumor necrosis factor alpha , microbiology and biotechnology , cell culture , immunology , biology , biochemistry , platelet , genetics
Accelerated wound healing by TP508, a thrombin‐derived synthetic peptide, may involve inflammatory mediators. The mechanism of action for TP508 is hypothesized to be integrin binding at its RGD site. THP‐1 monocytes were differentiated to an adherent macrophage phenotype with 50 ng/mL phorbol 12‐myristate 13‐acetate (PMA). Cells were pretreated with TP508 for 30 minutes, followed by lipopolysaccharide (LPS) for 3.5 hours. TNFα, IL‐8 and IL‐1 β were analyzed via ELISA. TP508 decreased expression of TNFα and IL‐8 and increased IL‐1 β expression independently of LPS. When heparin‐sulfate was used to stimulate TLR4 receptors, TP508 again reduced TNFα expression. Given the peptide sequence of TP508, direct blocking of the TLR4 receptor is improbable, so the TP508 RGD site was explored for potential interaction with TLR4‐dependent cytokine stimulation. Variants of TP508 were used to test whether the RGD‐integrin binding was responsible for the reduction in cytokine expression in these cells. An α V β 3 integrin blocking antibody was as effective in reducing LPS‐stimulated cytokine expression as the TLR4 activity‐blocking antibody. Treatment of cells with α V β 3 integrin‐binding peptide GRGDSP also significantly reduced TNFα expression in response to LPS. This preliminary evidence suggests that TP508 may modulate cytokine expression through an integrin dependent mechanism.