Hyperplasia and Cellularity Changes in IGF-1-Overexpressing Skeletal Muscle of Crucian Carp
Hyperplasia and Cellularity Changes in IGF-1-Overexpressing Skeletal Muscle of Crucian Carp
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DOI：
10.1210/en.2013-1938
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发表时间：
2014-06-01
期刊：
影响因子：
4.8
通讯作者：
Yin, Zhan
中科院分区：
文献类型：
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作者：
Li, Dongliang;Lou, Qiyong;Yin, Zhan
利用斑马鱼骨骼肌特异性启动子mylz2诱导鲫鱼过表达斑马鱼IGF-1 cDNA。在稳定的转基因种系F-1后代中，观察到骨骼肌中IGF-1水平增加了5倍。组织学分析显示转基因鱼骨骼肌增生明显。通过分析IGF-1转基因鱼和非转基因对照鱼15月龄骨骼肌的RNA测序转录组，根据相应的斑马鱼基因组信息，鉴定出10 966个显著表达水平的转录本，并确定了基因描述。根据我们的RNA测序转录组分析结果和实时定量PCR分析结果证实了骨骼肌转录组分析，发现在IGF-1过表达的转基因鱼中激活了几种途径，包括IGF-1信号转导、有氧代谢和蛋白质降解。有趣的是，我们的转录表达和蛋白质分析表明，IGF-1的过表达刺激了肌纤维类型向更氧化的慢肌类型的显著转变。虽然IGF-1转基因鱼的体重出人意料地下降，但与非转基因对照鱼相比，IGF-1过表达转基因鱼的耗氧量明显更高。上述结果表明，IGF-1在鲫鱼骨骼肌中持续过表达可促进肌纤维增生和细胞结构改变，从而引起机体能量代谢和骨骼肌生长的改变。
The zebrafish skeletal muscle-specific promoter mylz2 was used to cause crucian carp overexpression of the zebrafish IGF-1 cDNA. In stable transgenic germline F-1 progenies, a 5-fold increase in the level of IGF-1 in skeletal muscle was observed. Evident skeletal muscle hyperplasia was observed in the transgenic fish through histologic analysis. By analyzing the RNA sequencing transcriptome of the skeletal muscle of IGF-1 transgenic fish and nontransgenic control fish at 15 months of age, 10 966 transcripts with significant expression levels were identified with definite gene descriptions based on the corresponding zebrafish genome information. Based on the results of our RNA sequencing transcriptome profiling analysis and the results of the real-time quantitative PCR analysis performed to confirm the skeletal muscle transcriptomics analysis, several pathways, including IGF-1 signaling, aerobic metabolism, and protein degradation, were found to be activated in the IGF-1-overexpressing transgenic fish. Intriguingly, our transcriptional expression and protein assays indicated that the overexpression of IGF-1 stimulated a significant shift in the myofiber type toward a more oxidative slow muscle type. Although the body weight was surprisingly decreased by IGF-1 transgenic expression, significantly higher oxygen consumption rates were measured in IGF-1-overexpressing transgenic fish compared with their nontransgenic control fish. These results indicate that the sustained overexpression of IGF-1 in crucian carp skeletal muscle promotes myofiber hyperplasia and cellularity changes, which elicit alterations in the body energy metabolism and skeletal muscle growth.