The role of myosin regulatory light chain phosphorylation in heart diseases

• Project/Area Number: 15H04826
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Cardiovascular medicine
• Research Institution: National Cardiovascular Center Research Institute
• Principal Investigator: KITAKAZE Msafumi 国立研究開発法人国立循環器病研究センター, 研究開発基盤センター, 部長 (20294069)
• Co-Investigator(Kenkyū-buntansha): 瀬口 理 国立研究開発法人国立循環器病研究センター, 病院, 医長 (60570869) ; 山崎 悟 国立研究開発法人国立循環器病研究センター, 研究所, 室長 (70348796) ; 朝倉 正紀 国立研究開発法人国立循環器病研究センター, 研究開発基盤センター, 室長 (80443505) ; 中野 敦 国立研究開発法人国立循環器病研究センター, 研究開発基盤センター, 室長 (90648106)
• Research Collaborator: ITO Shin ; IMAZU Miki ; FUKUDA Hiroki ; HITUMOTO Taturo ; NAKAJIMA Yuri
• Project Period (FY): 2015-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥17,680,000 (Direct Cost: ¥13,600,000、Indirect Cost: ¥4,080,000); Fiscal Year 2017: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000); Fiscal Year 2016: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000); Fiscal Year 2015: ¥6,630,000 (Direct Cost: ¥5,100,000、Indirect Cost: ¥1,530,000)
• Keywords: 循環器・高血圧 / 虚血性疾患 / 心筋梗塞 / 心筋保護 / 虚血性心疾患

Outline of Final Research Achievements

Hypoxia significantly decreased the level of MLC2v phosphorylation in cultured neonatal cardiac myocytes. Canine failing hearts induced by high-frequency pacing also showed decreased level of MLC2v phosphorylation. Importantly, we identified the familial dilated cardiomyopathy associated with MYLK3 mutation. This truncating mutant cMLCK completely lacks the kinase activity, although it did not affect wild-type cMLCK activity. These results indicated that the depressed cMLCK kinase activity was associated with significant decrease in MLC2v phosphorylation and possibly with development of DCM in human. Finally, we tried to develop the specific modulators of cMLCK activity and identified 8 pseudo-peptides which can bind to cMLCK specifically with high affinity. We checked the effects of the 8 pseudo-peptides on the cMLCK activity and found that only one pseudo-peptide specifically inhibited cMLCK activity. However, we could not get the pseudo-peptide that can activate cMLCK.

Academic Significance and Societal Importance of the Research Achievements

心不全の重要な原因である虚血および低酸素によりミオシン調節軽鎖（MLC2v）のリン酸化が低下すること、そして大動物心不全モデルでも心筋細胞のMLC2vリン酸化が低下することを証明したことは心不全の病態発症の新しい機序を解明したという点で意義が高い。さらに、cMLCK活性の低下がヒトにおいても実施に収縮性心不全の原因になることを証明できたことは、実臨床においても極めて意義深く、収縮性心不全の新しい治療標的としてcMLCKが注目される研究と考えられる。

Research Products

• [Journal Article] Impact of cardiac myosin light chain kinase gene mutation on development of dilated cardiomyopathy (2019)
  • Author(s): Hodatsu A, Fujino N, Uyama Y, Tsukamoto O, Imai-Okazaki A, Yamazaki S, Seguchi O, Konno T, Hayashi K, Kawashiri MA, Asano Y, Kitakaze M, Takashima S, Yamagishi M
  • Journal Title: ESC Heart Fail Volume: 6 Issue: 2 Pages: 06-415
  • DOI: 10.1002/ehf2.12410
  • Peer Reviewed / Open Access