Inhibitor of Tec kinase, LFM-A13, decreases pro-inflammatory mediators production in LPS-stimulated RAW264.7 macrophages via NF-κB pathway

Tec kinase, a prototypical member of the Tec tyrosine kinases family, was shown to mainly govern lymphocyte proliferation. In the present study, we investigated the role of Tec kinase in acute inflammatory response in lipopolysaccharide (LPS) challenge. First, we demonstrate that Tec kinase activity was observed in RAW264.7 macrophages exposed to LPS. Tec and phosphorylated Tec expression were upregulated in a dose- and time-dependent manner after LPS stimulation. LPS increased monocyte chemotactic protein (MCP)-1 secretion and intercellular adhesion molecule (ICAM)-1 expression, and increasing mRNA expression was consistently observed. LPS also induced IκBα phoshporylaytion and its degradation, increased NF-κB p65 phoshporylaytion and translocation to nuclei in RAW264.7 cells. Pretreatment with LFM-A13 decreased LPS-induced cytokines and chemokines production and mRNA levels, blocked NF-κB transactivation. These effects of LPS were also prevented by Tec-siRNA. Additionally, LFM-A13 or Tec-siRNA obviously inhibited LPS-induced TGFβ-activated kinase 1(TAK1) phosphorylation. Taken together, our results suggest that Tec kinase involves in acute inflammation process in LPS-stimulated RAW264.7 cells, at least mediated by activating TAK1/ NF-κB signal pathway.