講演情報
[O3-5]様々な免疫形質と関連するCD28領域におけるスプライシング制御バリアントの同定
○人見 祐基1, 相葉 佳洋2, 植野 和子3, 西田 奈央3, 河合 洋介3, 川嶋 実苗4, 築地 信5, 岩渕 千里1, 高田 紗奈美1, 三宅 紀子1, 長崎 正朗6, 徳永 勝士3, 中村 稔2,7 (1.国立国際医療研究センター研究所 疾患ゲノム研究部, 2.長崎医療センター 臨床研究センター, 3.国立国際医療研究センター研究所 ゲノム医科学プロジェクト, 4.科学技術振興機構, 5.星薬科大学 薬学部 微生物学研究室, 6.京都大学 学際融合教育研究推進センター スーパーグローバルコース医学生命系ユニット, 7.長崎大学 大学院医歯薬学総合研究科 新興感染症病態制御学系専攻 肝臓病学講座)
CD28 is crucial for the activation of T-cells. Recent genome-wide association studies (GWAS) identified CD28 as a susceptibility locus for multiple immunological traits such as allergic diseases and autoimmune diseases. However, the primary functional variant in this locus and the molecular mechanisms by which disease susceptibility is conferred have not been elucidated. This study aimed to identify the primary functional variant among thousands of genetic variants in the CD28 locus and to elucidate its functional effect on the CD28 molecule.
Among the variants which showed stronger linkage disequilibrium (LD) with all GWAS-lead variants for each immunological trait in CD28, rs2013278, which was located in the Fox-1 binding motif related to splicing regulation, was identified as a primary functional variant by in silico/in vitro functional analyses. Endogenous quantity ratio of mainly expressed splicing isoforms of CD28 (Full-length CD28, CD28i, and CD28Δex2) in allele knock-in version of cell lines using CRISPR/Cas9 were regulated by rs2013278 directly. Although full-length CD28 protein showed a higher binding affinity with its ligand CD80/CD86, both CD28i and CD28Δex2 encoded the loss-of-function isoform products.
This study identified a primary functional variant that regulates the splicing of CD28 and revealed the molecular mechanisms through which it confers susceptibility to multiple immunological traits. We also illustrated an efficient post-GWAS approach applicable to various complex diseases.
Among the variants which showed stronger linkage disequilibrium (LD) with all GWAS-lead variants for each immunological trait in CD28, rs2013278, which was located in the Fox-1 binding motif related to splicing regulation, was identified as a primary functional variant by in silico/in vitro functional analyses. Endogenous quantity ratio of mainly expressed splicing isoforms of CD28 (Full-length CD28, CD28i, and CD28Δex2) in allele knock-in version of cell lines using CRISPR/Cas9 were regulated by rs2013278 directly. Although full-length CD28 protein showed a higher binding affinity with its ligand CD80/CD86, both CD28i and CD28Δex2 encoded the loss-of-function isoform products.
This study identified a primary functional variant that regulates the splicing of CD28 and revealed the molecular mechanisms through which it confers susceptibility to multiple immunological traits. We also illustrated an efficient post-GWAS approach applicable to various complex diseases.