A Single Nucleotide Polymorphism in 3′-Untranslated Region Contributes to the Regulation of Toll-like Receptor 4 Translation

• Published in: The Journal of biological chemistry Vol. 287; no. 30; pp. 25163 - 25172
• Main Authors: Sato, Kayo, Yoshimura, Atsutoshi, Kaneko, Takashi, Ukai, Takashi, Ozaki, Yukio, Nakamura, Hirotaka, Li, Xinyue, Matsumura, Hiroyoshi, Hara, Yoshitaka, Ogata, Yorimasa
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 20.07.2012; American Society for Biochemistry and Molecular Biology
• Subjects: 3' Untranslated Regions - genetics; Alleles; Asian Continental Ancestry Group; Cell Line; Female; Gene Regulation; Genetic Polymorphism; Humans; Innate Immunity; Interleukin-6 - biosynthesis; Interleukin-6 - genetics; Interleukin-8 - genetics; Interleukin-8 - metabolism; Japan; Leukocytes, Mononuclear - metabolism; Lipopeptides - pharmacology; Lipopolysaccharide (LPS); Lipopolysaccharides - pharmacology; Male; MicroRNA; MicroRNAs - genetics; MicroRNAs - metabolism; Periodontal Disease; Periodontitis - genetics; Periodontitis - metabolism; Polymorphism, Single Nucleotide; Protein Biosynthesis; Toll-Like Receptor 4 - biosynthesis; Toll-Like Receptor 4 - genetics; Toll-like Receptors (TLR); Japan; Gene Regulation; Toll-like Receptors (TLR); MicroRNA; Innate Immunity; Periodontal Disease; Genetic Polymorphism; Lipopolysaccharide (LPS)
• DOI: 10.1074/jbc.M111.338426
• ISSN: 0021-9258; 1083-351X

Background: Genetic variation of SNP rs11536889 in 3′-UTR of TLR4 is implicated in certain diseases, including periodontitis, gastric atrophy, and prostate cancer. Results: The G allele of rs11536889 inhibited translation, but not transcription, of TLR4. Conclusion: Genetic variation of rs11536889 regulates TLR4 expression. Significance: Polymorphism in rs11536889 could be an excellent genetic marker for the diseases caused by TLR4-ligands. We have previously shown that a single nucleotide polymorphism rs11536889 in the 3′-untranslated region (UTR) of TLR4 was associated with periodontitis. In this study the effects of this single nucleotide polymorphism on Toll-like receptor (TLR) 4 expression were investigated. Monocytes from subjects with the C/C genotype expressed higher levels of TLR4 on their surfaces than those from subjects with the other genotypes. Peripheral blood mononuclear cells (PBMCs) from the C/C and G/C subjects secreted higher levels of IL-8 in response to lipopolysaccharide (LPS), a TLR4 ligand, than the cells from the G/G subjects. However, there was no significant difference in TLR4 mRNA levels in PBMCs from the subjects with each genotype. After stimulation with tripalmitoylated CSK4 (Pam3CSK4), TLR4 mRNA levels increased in PBMCs from both the C/C and G/G subjects, whereas TLR4 protein levels increased in PBMCs from the C/C but not G/G subjects. Transient transfection of a series of chimeric luciferase constructs revealed that a fragment of 3′-UTR containing rs11536889 G allele, but not C allele, suppressed luciferase activity induced by LPS or IL-6. Two microRNAs, hsa-miR-1236 and hsa-miR-642a, were predicted to bind to rs11536889 G allele. Inhibition of these microRNAs reversed the suppressed luciferase activity. These microRNA inhibitors also up-regulated endogenous TLR4 protein on THP-1 cells (the G/G genotype) after LPS stimulation. Furthermore, mutant microRNAs that bind to the C allele inhibited the luciferase activity of the construct containing the C allele. These results indicate that genetic variation of rs11536889 contributes to translational regulation of TLR4, possibly by binding to microRNAs.