Differential Expression of miRNAs in Skeletal Muscle of Rainbow Trout Under the Influence of Estrogen

Sexual development and maturation in rainbow trout involve the processes of vitellogenesis and spawning, during which there is a release of hormone estrogen and high-energy demand. Skeletal muscle is an immediate endogenous energy source to address the demand leading to an imbalance in protein turnover. This imbalance results in poor quality muscle. Different myogenic factors and miRNAs contribute to the process of muscle development. The present study is to identify the differentially expressed miRNAs in skeletal muscle under the influence of estrogen. RNA from estrogen treated (5ug/g) and control fish were subjected to next generation sequencing using illumina platform. Total unique miRNA reads generated were 2409, among which, 169 were previously reported in rainbow trout and 507 specific to Pisces. Of the predicted miRNAs 817 were reported to be novel. Statistical analysis reveled a total of 76 differentially expressed miRNAs, including 10 miRNAs novel to rainbow trout (p-value < 0.05). Four of the 5 differentially expressed miRNAs were validated by RT-qPCR. Important myogenic miRNAs including miR-1, miR-133a, miR-126, miR-145, miR-499 and miR-206 were either up regulated or down regulated under the influence of estrogen. Target prediction for the differentially expressed novel miRNA was performed using PITA and miRANDA. This study helps in understanding the role of miRNAs contributing to the myogenic changes during sexual development of rainbow trout.