Open AccessG‐CSF‐mediated inhibition of JNK is a key mechanism for Lactobacillus rhamnosus ‐induced suppression of TNF production in macrophages
Author(s) -
Kim Sung O.,
Sheikh Haroon I.,
Ha SoonDuck,
Martins Andrew,
Reid Gregor
Publication year - 2006
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1111/j.1462-5822.2006.00763.x
Subject(s) - lactobacillus rhamnosus , tumor necrosis factor alpha , biology , microbiology and biotechnology , lipopolysaccharide , cytokine , kinase , immunology , lactobacillus , bacteria , genetics
Summary Lactobacillus rhamnosus is a human commensal with known immunomodulatory properties. To date the mechanism of these immunomodulatory effects is not well understood. To unravel the immunomodulatory signalling mechanism, we investigated the effects of two strains of L. rhamnosus , L. rhamnosus GG and GR‐1, in modulating production of tumour necrosis factor‐α (TNF) in human monocytic cell line THP‐1 and mouse macrophages. Live L. rhamnosus GG and GR‐1 or their spent culture supernatant induced minuscule amounts of TNF production but large quantities of granulocyte‐colony stimulating factor (G‐CSF) in macrophages compared with those induced by pathogenic Escherichia coli GR‐12 and Enterococcus faecalis . By using neutralizing antibodies and G‐CSF receptor knockout mice, we demonstrated that G‐CSF secreted from L. rhamnosus GG‐ and GR‐1‐exposed macrophages suppressed TNF production induced by E. coli ‐ or lipopolysaccharide‐activated macrophages through a paracrine route. The suppression of TNF production by G‐CSF was mediated through activation of STAT3 and subsequent inhibition of c‐Jun‐N‐terminal kinases (JNKs). The inhibition of JNK activation required STAT3α‐mediated de novo protein synthesis. This demonstrates a novel role of G‐CSF in L. rhamnosus ‐triggered anti‐inflammatory effects and its mechanism in the suppression of TNF production in macrophages.