R753Q single-nucleotide polymorphism impairs toll-like receptor 2 recognition of hepatitis C virus core and nonstructural 3 proteins.
BACKGROUND
Hepatitis C virus (HCV) core and nonstructural (NS) 3 proteins induce inflammation and immunity through a toll-like receptor (TLR) 2-dependent pathway. Individuals with the R753Q single-nucleotide polymorphism (SNP) in the TLR2 gene have increased the risk of allograft failure after liver transplantation for chronic hepatitis C.


METHODS
To test the hypothesis that R753Q SNP impairs TLR2 recognition of HCV proteins, a series of in vitro experiments were performed wherein stable clones of wild-type TLR2-deficient human embryonic kidney (HEK) 293 cells and HEK293 cells transfected with wild-type (HEK293-TLR2) or variant TLR2 genes (HEK293-TLR2-R753Q) were stimulated with HCV core and NS3 proteins. Cellular activation was assessed by nuclear factor-kappa B-driven luciferase activity, cytokine secretion, and gene upregulation.


RESULTS
Compared with TLR2-deficient HEK293 cells, HEK293-TLR2 cells had marked nuclear factor-kappa B-driven luciferase activity, had modest to marked upregulation in TLR2 signaling-associated genes, and secreted large quantities of interleukin-8 during exposure to HCV core and NS3 proteins. In contrast, HEK293-TLR2-R753Q cells did not respond to stimulation with HCV and behaved similarly like TLR2-deficient HEK293 cells.


CONCLUSIONS
R753Q SNP impairs TLR2-mediated immune recognition of HCV core and NS3 proteins. This biologic defect may account for the predisposition of patients to develop allograft failure after liver transplantation for chronic hepatitis C.
Brown
Robert A
RA
Division of Infectious Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA.
Gralewski
Jonathon H
JH
Eid
Albert J
AJ
Knoll
Bettina M
BM
Finberg
Robert W
RW
Razonable
Raymund R
RR
D002460:Cell Line; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006085:Graft Survival; D019698:Hepatitis C, Chronic / Q000276:immunology / Q000601:surgery; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics; D016209:Interleukin-8 / Q000378:metabolism; D016031:Liver Transplantation; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D014162:Transfection; D014184:Transplantation, Homologous; D014758:Viral Core Proteins / Q000276:immunology* / Q000378:metabolism; D017361:Viral Nonstructural Proteins / Q000276:immunology* / Q000378:metabolism; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D016209:Interleukin-8; D016328:NF-kappa B; D051195:Toll-Like Receptor 2; D014758:Viral Core Proteins; D017361:Viral Nonstructural Proteins; C508606:CXCL8 protein, human; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C495342:TLR2 protein, human