Skip to main content
  • Meeting abstract
  • Open access
  • Published:

MicroRNA-3148 modulates differential gene expression of the SLE-associated TLR7 variant

Background

We identified the G allele of TLR7 3'-UTR SNP (rs3853839) associated with increased TLR7 transcripts, a more pronounced IFN signature and risk for SLE in 9,274 Eastern Asians (Pcombined = 6.5 × 10-10) [1]. The current study sought replication of SLE-associated SNP(s) in non-Asian ancestries and explored molecular mechanisms underlying an identified gene variant that affects TLR7 expression.

Methods

We conducted genotyping, imputation and association for 98 to 116 SNPs (varying among different ancestries) covering 80 kb of TLR7-TLR8 in European Americans (EA), African Americans (AA) and Hispanics enriched for the Amerindian-European admixture (HS). Haplotype-based conditional testing was conducted to distinguish independent association signals. Mantel-Haenszel testing was used in transancestral meta-analysis. Association of genotypes with TLR7 expression was examined using RT-PCR, flow cytometry and reporter assays. Pyrosequencing was used to measure allelic variations in TLR7 transcript levels.

Results

The rs3853839 was confirmed as the only variant within TLR7-TLR8 exhibiting consistent and independent association with SLE in our transancestral fine-mapping (Pmeta = 7.5 × 10-11, OR (95% CI) = 1.24 (1.18 to 1.34)) in 13,339 subjects of EA (3,936 cases vs. 3,491 controls), AA (1,679 vs. 1,934) and HS (1,492 vs. 807) ancestries. PBMCs from normal G-allele carriers exhibited elevated levels of TLR7 mRNA (P = 0.01 in men and P = 0.02 in women) and protein (P = 0.009 in men and P = 0.038 in women). PBMCs from heterozygotes exhibited higher G/C allele ratios of TLR7 transcripts 4 hours after incubation with actinomycin D (inhibitor of transcription initiation) (P = 0.04), indicating slower degradation of G allele-containing transcript. The nonrisk allele, but not the risk allele, was predicted to match microRNA-3148 (miR-3148) at the second base in the binding site. Transcript levels of miR-3148 and TLR7 were inversely correlated in PBMCs from 16 SLE patients and 21 controls (R2 = 0.255, P = 0.001), suggesting miR-3148 modulating TLR7 expression. Overexpression of miR-3148 via transfection into HEK 293 cells led to a more than twofold reduction in luciferase activity driven by the TLR7 3'-UTR segment containing the nonrisk allele than that containing the risk allele (P = 0.001).

Conclusion

We identified and confirmed a genome-wide significant association between rs3853839 and SLE susceptibility in 22,613 subjects of Eastern Asian, EA, AA and HS ancestries (Pmeta = 6.4 × 10-19, OR (95% CI) = 1.26 (1.20 to 1.32)). Reduced modulation by miR-3148 confers slower degradation of the risk allele containing TLR7 transcript, resulting in elevated levels of gene products and a more robust type I IFN signature.

References

  1. Shen N, Fu Q, Deng Y, Qian X, Zhao J, Kaufman KM, Wu YL, Yu CY, Tang Y, Chen JY, Yang W, Wong M, Kawasaki A, Tsuchiya N, Sumida T, Kawaguchi Y, Howe HS, Mok MY, Bang SY, Liu FL, Chang DM, Takasaki Y, Hashimoto H, Harley JB, Guthridge JM, Grossman JM, Cantor RM, Song YW, Bae SC, Chen S: Sex-specific association of X-linked Toll-like receptor 7 (TLR7) with male systemic lupus erythematosus. Proc Natl Acad Sci USA. 2010, 107: 15838-15843. 10.1073/pnas.1001337107.

    Article  PubMed Central  CAS  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Consortia

Rights and permissions

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article

Deng, Y., Zhao, J., Sakurai, D. et al. MicroRNA-3148 modulates differential gene expression of the SLE-associated TLR7 variant. Arthritis Res Ther 14 (Suppl 3), A5 (2012). https://doi.org/10.1186/ar3939

Download citation

  • Published:

  • DOI: https://doi.org/10.1186/ar3939

Keywords