Investigation of a causal gene of familial myelodysplastic syndromes and its molecular mechanism

• Project/Area Number: 17K16181
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Hematology
• Research Institution: The University of Tokyo
• Principal Investigator: TAKAOKA KENSUKE 東京大学, 医学部附属病院, 助教 (60793180)
• Project Period (FY): 2017-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2018: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000); Fiscal Year 2017: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: 家族性骨髄異形成症候群 / 癌 / 内科

Outline of Final Research Achievements

Previous our research revealed that HLTF E259K is one of the candidate gene mutations of familial MDS. Molecularly, we found that an E259K mutation reduced the binding capacity of HLTF with MMS2. In murine bone marrow transplantation experiments, we revealed that the peripheral blood chimerism of the recipients with Hltf knockdown cells tended to be greater than that of control mice. We also found that the bone marrow c-kit positivity was also increased in Hltf shRNA-transduced cells compared with control-transduced cells in the bone marrow transplantation assay. To evaluate whether the HLTF mutation actually contributes to a DNA double-strand break repair deficiency, we performed mutation signature analysis of somatic mutations in samples of both MDS patients. BRCA mutational signature was detected in both familial MDS patients, suggesting that a DNA double-strand break repair was impaired in the HLTF-mutated familial MDS somatic samples.

Academic Significance and Societal Importance of the Research Achievements

先行研究と併せ、家族性骨髄異形成症候群（MDS）の家系を用いて未報告のHLTF E259K 生殖細胞変異を同定し、患者検体においてDNA二本鎖切断修復低下を示唆するBRCA変異シグネチャーを明らかにした。分子機構として、HLTF変異体とMMS2との複合体形成能が低下し、（先行研究と併せ）PCNAポリユビキチン化が障害されていることを示した。稀少疾患であり分子機構も未知の部分が多い家族性MDSの検体を用いて全エクソンシーケンスを施行し未報告の生殖細胞変異を同定、さらには機能解析まで施行した本研究の意義は大きいと考えられる。今後HLTFと血液腫瘍のさらなる解析が望まれる。

Research Products

• [Journal Article] A germline HLTF mutation in familial MDS induces DNA damage accumulation through impaired PCNA polyubiquitination (2019)
  • Author(s): Takaoka Kensuke、Kawazu Masahito、Koya Junji、Yoshimi Akihide、Masamoto Yosuke、Maki Hiroaki、Toya Takashi、Kobayashi Takashi、Nannya Yasuhito、Arai Shunya、Ueno Toshihide、Ueno Hironori、Suzuki Kenshi、Harada Hironori、Manabe Atsushi、Hayashi Yasuhide、Mano Hiroyuki、Kurokawa Mineo
  • Journal Title: Leukemia Volume: 印刷中 Issue: 7 Pages: 1773-1782
  • DOI: 10.1038/s41375-019-0385-0
  • Peer Reviewed
• [Presentation] 家族性骨髄異形成症候群から得られたHLTF変異によりPCNAのポリユビキチン化が損なわれDNA損傷が蓄積する (2017)
  • Author(s): 髙岡賢輔、河津正人、古屋淳史、吉見昭秀、牧宏彰、遠矢嵩、南谷泰仁、荒井俊也、上野博則、原田浩徳、林泰秀、間野博行、黒川峰夫
  • Organizer: 第76回日本癌学会学術総会
• [Presentation] 家族性MDSにおけるHLTF変異によりPCNAのポリユビキチン化が損なわれDNA損傷が蓄積する (2017)
  • Author(s): 髙岡賢輔、河津正人、古屋淳史、吉見昭秀、牧宏彰、遠矢嵩、小林隆、南谷泰仁、荒井俊也、上野博則、鈴木憲史、原田浩徳、真部淳、林泰秀、間野博行、黒川峰夫
  • Organizer: 第79回日本血液学会学術総会
• [Presentation] Human Germline HLTF E259K Mutation Identified in Familial MDS Patients Accumulates DNA Damage through Impaired PCNA Polyubiquitination (2017)
  • Author(s): Kensuke Takaoka, Masahito Kawazu, Junji Koya, Akihide Yoshimi, Yosuke Masamoto, Hiroaki Maki, Takashi Toya, Takashi Kobayashi, Yasuhito Nannya, Shunya Arai, Hironori Ueno, Kenshi Suzuki, Hironori Harada, Atsushi Manabe, Yasuhide Hayashi, Hiroyuki Mano, Mineo Kurokawa
  • Organizer: 59th ASH Annual Meeting & Exposition
  • Int'l Joint Research