Duran Bruno Oliveira da Silva, Fernandez Geysson Javier, Mareco Edson Assunção, Moraes Leonardo Nazario, Salomão Rondinelle Artur Simões, Gutierrez de Paula Tassiana, Santos Vander Bruno, Carvalho Robson Francisco, Dal-Pai-Silva Maeli
Department of Morphology, Institute of Biosciences of Botucatu, São Paulo State University, Botucatu, São Paulo, Brazil.
Aquaculture Center, São Paulo State University, Jaboticabal, São Paulo, Brazil.
PLoS One. 2015 Nov 3;10(11):e0141967. doi: 10.1371/journal.pone.0141967. eCollection 2015.
Pacu (Piaractus mesopotamicus) is a Brazilian fish with a high economic value in pisciculture due to its rusticity and fast growth. Postnatal growth of skeletal muscle in fish occurs by hyperplasia and/or hypertrophy, processes that are dependent on the proliferation and differentiation of myoblasts. A class of small noncoding RNAs, known as microRNAs (miRNAs), represses the expression of target mRNAs, and many studies have demonstrated that miR-1, miR-133, miR-206 and miR-499 regulate different processes in skeletal muscle through the mRNA silencing of hdac4 (histone deacetylase 4), srf (serum response factor), pax7 (paired box 7) and sox6 ((sex determining region Y)-box 6), respectively. The aim of our work was to evaluate the expression of these miRNAs and their putative target mRNAs in fast- and slow-twitch skeletal muscle of pacu during growth. We used pacus in three different development stages: larval (aged 30 days), juvenile (aged 90 days and 150 days) and adult (aged 2 years). To complement our study, we also performed a pacu myoblast cell culture, which allowed us to investigate miRNA expression in the progression from myoblast proliferation to differentiation. Our results revealed an inverse correlation between the expression of the miRNAs and their target mRNAs, and there was evidence that miR-1 and miR-206 may regulate the differentiation of myoblasts, whereas miR-133 may regulate the proliferation of these cells. miR-499 was highly expressed in slow-twitch muscle, which suggests its involvement in the specification of the slow phenotype in muscle fibers. The expression of these miRNAs exhibited variations between different development stages and between distinct muscle twitch phenotypes. This work provides the first identification of miRNA expression profiles in pacu skeletal muscle and suggests an important role of these molecules in muscle growth and in the maintenance of the muscle phenotype.
淡水白鲳（Piaractus mesopotamicus）是一种巴西鱼类，因其适应性强和生长速度快，在水产养殖中具有很高的经济价值。鱼类骨骼肌的出生后生长通过细胞增生和/或肥大发生，这些过程依赖于成肌细胞的增殖和分化。一类被称为微小RNA（miRNA）的小非编码RNA可抑制靶mRNA的表达，许多研究表明，miR-1、miR-133、miR-206和miR-499分别通过对组蛋白去乙酰化酶4（hdac4）、血清反应因子（srf）、配对盒7（pax7）和（性别决定区Y）-盒6（sox6）的mRNA沉默来调节骨骼肌中的不同过程。我们研究的目的是评估这些miRNA及其假定靶mRNA在淡水白鲳生长过程中的快、慢肌骨骼肌中的表达。我们使用了处于三个不同发育阶段的淡水白鲳：幼体（30日龄）、幼鱼（90日龄和150日龄）和成鱼（2岁）。为补充我们的研究，我们还进行了淡水白鲳成肌细胞培养，这使我们能够研究从成肌细胞增殖到分化过程中的miRNA表达。我们的结果揭示了miRNA与其靶mRNA表达之间的负相关，并且有证据表明miR-1和miR-206可能调节成肌细胞的分化，而miR-133可能调节这些细胞的增殖。miR-499在慢肌中高度表达，这表明它参与了肌纤维慢表型的特化。这些miRNA的表达在不同发育阶段和不同肌肉抽搐表型之间存在差异。这项工作首次鉴定了淡水白鲳骨骼肌中的miRNA表达谱，并表明这些分子在肌肉生长和肌肉表型维持中具有重要作用。
