TY - JOUR
T1 - Functional linkage of cirrhosis-predictive single nucleotide polymorphisms of toll-like receptor 4 to hepatic stellate cell responses
AU - Guo, Jinsheng
AU - Loke, Johnny
AU - Zheng, Feng
AU - Hong, Feng
AU - Yea, Steven
AU - Fukata, Masayuki
AU - Tarocchi, Mirko
AU - Abar, Olivia T.
AU - Huang, Hongjin
AU - Sninsky, John J.
AU - Friedman, Scott I.
PY - 2009
Y1 - 2009
N2 - In a recent study, a single nucleotide polymorphism (SNP) of the Toll-like receptor 4 (TLR4) gene (c.1196C>T [rs4986791, p.T399I]) emerged as conferring protection from fibrosis progression compared to a major, wild-type (WT) CC allele (p.T399). The present study examined the functional linkage of this SNP, along with another common, highly cosegregated TLR4 SNP (c.896A>G [rs4986790, p.D299G]), to hepatic stellate cell (HSC) responses. Both HSCs from TLR4-/- mice and a human HSC line (LX-2) reconstituted with either TLR4 D299G and/or T399I complementary DNAs were hyporesponsive to lipopolysaccharide (LPS) stimulation compared to those expressing WT TLR4, as assessed by the expression and secretion of LPS-induced inflammatory and chemotactic cytokines (i.e., monocyte chemoattractant protein-1, interleukin-6), down-regulation of bone morphogenic protein and the activin membrane-bound inhibitor expression (an inhibitory transforming growth factor β pseudoreceptor), and activation of a nuclear factor κB (NF-κB)-responsive luciferase reporter. In addition, spontaneous apoptosis, as well as apoptosis induced by pathway inhibitors of NF-κB, extracellular signal-regulated kinase (ERK), and phosphatidylinositol 3-kinase were greatly increased in HSCs from either TLR4-/- or myeloid differentiation factor 88-/- (a TLR adaptor protein) mice, as well as in murine HSCs expressing D299G and/or T399I SNPs; increased apoptosis in these lines was accompanied by decreased phospho-ERK and Bcl-2. Conclusion: TLR4 D299G and T399I SNPs that are associated with protection from hepatic fibrosis reduce TLR4-mediated inflammatory and fibrogenic signaling and lower the apoptotic threshold of activated HSCs. These findings provide a mechanistic link that explains how specific TLR4 SNPs may regulate the risk of fibrosis progression.
AB - In a recent study, a single nucleotide polymorphism (SNP) of the Toll-like receptor 4 (TLR4) gene (c.1196C>T [rs4986791, p.T399I]) emerged as conferring protection from fibrosis progression compared to a major, wild-type (WT) CC allele (p.T399). The present study examined the functional linkage of this SNP, along with another common, highly cosegregated TLR4 SNP (c.896A>G [rs4986790, p.D299G]), to hepatic stellate cell (HSC) responses. Both HSCs from TLR4-/- mice and a human HSC line (LX-2) reconstituted with either TLR4 D299G and/or T399I complementary DNAs were hyporesponsive to lipopolysaccharide (LPS) stimulation compared to those expressing WT TLR4, as assessed by the expression and secretion of LPS-induced inflammatory and chemotactic cytokines (i.e., monocyte chemoattractant protein-1, interleukin-6), down-regulation of bone morphogenic protein and the activin membrane-bound inhibitor expression (an inhibitory transforming growth factor β pseudoreceptor), and activation of a nuclear factor κB (NF-κB)-responsive luciferase reporter. In addition, spontaneous apoptosis, as well as apoptosis induced by pathway inhibitors of NF-κB, extracellular signal-regulated kinase (ERK), and phosphatidylinositol 3-kinase were greatly increased in HSCs from either TLR4-/- or myeloid differentiation factor 88-/- (a TLR adaptor protein) mice, as well as in murine HSCs expressing D299G and/or T399I SNPs; increased apoptosis in these lines was accompanied by decreased phospho-ERK and Bcl-2. Conclusion: TLR4 D299G and T399I SNPs that are associated with protection from hepatic fibrosis reduce TLR4-mediated inflammatory and fibrogenic signaling and lower the apoptotic threshold of activated HSCs. These findings provide a mechanistic link that explains how specific TLR4 SNPs may regulate the risk of fibrosis progression.
UR - http://www.scopus.com/inward/record.url?scp=63349103768&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=63349103768&partnerID=8YFLogxK
U2 - 10.1002/hep.22697
DO - 10.1002/hep.22697
M3 - Article
C2 - 19085953
AN - SCOPUS:63349103768
SN - 0270-9139
VL - 49
SP - 960
EP - 968
JO - Hepatology
JF - Hepatology
IS - 3
ER -