Muscle hypertrophic mechanism without exercise using tadpole model

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K20161
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 59040:Nutrition science and health science-related
• Research Institution: Nihon University
• Principal Investigator: INOUE Naoko 日本大学, 生物資源科学部, 准教授 (00509515)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 骨格筋 / 脂質 / タンパク質 / イメージング

Outline of Final Research Achievements

We performed a proteome analysis for skeletal muscle of tadpole tail. As a result, we found about 4000 proteins, and we realized tadpole tail was mainly composed of fast fibers. On the other hand, we also demonstrated to make unique muscle hypertrophy model “Predation exposure model” and tried to find expression difference of proteins and lipids. We set control (no predation) and Yago-EX (predation exposure) and compared the difference between them. As a result, upstream analyses clearly presented drastic changes in their metabolic conditions. Furthermore, we found significant accumulation of triacylglycerol in their hypertrophied tail muscles. Triacylglycerol was enriched in slow fiber muscle, we realized predation exposure resulted in fiber shift from fast to slow fibers. In mammals, slow muscle is resistant to atrophy, which is important to prevention of sarcopenia. In the future, we will try to investigate upstream regulators to shift these muscles.

Free Research Field

脂質生化学

Academic Significance and Societal Importance of the Research Achievements

学術的な進展として、本研究で用いた運動非依存的な捕食者ストレス誘導型骨格筋肥大は、運動による肥大システムとは異なるシステムを用いて肥大していることが明らかとなった。具体的に、運動による筋肥大では主に速筋線維が肥大することがわかっているが、今回の肥大モデルでは肥大に伴い遅筋線維が増加している様子をタンパク質及び脂質代謝物から明らかにすることができた。遅筋は筋萎縮が起こりにくく、サルコペニア予防のためには遅筋を増やすことが効果的であるといわれている。今後、如何にして筋肥大と同時に遅筋へのシフトが起こるのか、その作用因子を同定することができれば、我々の生活への応用も期待される結果が得られると考える。