Altered microRNA expression in bovine skeletal muscle with age

Summary Age‐dependent decline in skeletal muscle function leads to several inherited and acquired muscular disorders in elderly individuals. The levels of micro RNA s (mi RNA s) could be altered during muscle maintenance and repair. We therefore performed a comprehensive investigation for mi RNA s from five different periods of bovine skeletal muscle development using next‐generation small RNA sequencing. In total, 511 mi RNA s, including one putatively novel mi RNA , were identified. Thirty‐six mi RNA s were differentially expressed between prenatal and postnatal stages of muscle development including several myomi R s (mi R ‐1, mi R ‐206 and let‐7 families). Compared with mi RNA expression between different muscle tissues, 14 mi RNA s were up‐regulated and 22 mi RNA s were down‐regulated in the muscle of postnatal stage. In addition, a novel mi RNA was predicted and submitted to the mi RB ase database as bta‐mir‐10020. A dual luciferase reporter assay was used to demonstrate that bta‐mir‐10020 directly targeted the 3′‐ UTR of the bovine ANGPT 1 gene. The overexpression of bta‐mir‐10020 significantly decreased the D s R ed fluorescence in the wild‐type expression cassette compared to the mutant type. Using three computational approaches – miranda , pita and rnahybrid – these differentially expressed mi RNA s were also predicted to target 3609 bovine genes. Disease and biological function analyses and the KEGG pathway analysis revealed that these targets were statistically enriched in functionality for muscle growth and disease. Our mi RNA expression analysis findings from different states of muscle development and aging significantly expand the repertoire of bovine mi RNA s now shown to be expressed in muscle and could contribute to further studies on growth and developmental disorders in this tissue type.