miRNA transcriptome and myofiber characteristics of lamb skeletal muscle during hypertrophic growth1

Abstract

Postnatal muscle growth is achieved through hypertrophy of the muscle fibers and is impacted by the activity of satellite cells, the quiescent muscle stem cell. Several miRNAs are preferentially expressed in skeletal muscle and could provide a mechanism for increasing muscle hypertrophy through satellite cell proliferation and/or differentiation. The objectives of this study were to: 1) Characterize the miRNA transcriptome of the longissimus thoracis et lumborum muscle at several developmental timepoints [gestational d 85 (PN1), 110 (PN2), 133 (PN3), postnatal d 42 (PW1), 65 (PW2), 243 (MAT)] during muscle hypertrophy in lambs, and 2) examine miR-29a, identified in sequencing to be differentially regulated across development, loss of function on satellite cell proliferation and differentiation. Muscle fiber characteristics showed drastic increases (p < 0.0001) in fiber size and alterations in muscle fiber type occur during pre and postnatal development. miRNA sequencing comparisons were performed in developmental order (PN1 vs. PN2, PN2 vs. PN3, PN3 vs. PW1, PW1 vs. PW2, PW2 vs. MAT). There were 184 differentially expressed (Padj < 0.05) miRNA, 142 unique miRNA, from all 5 comparisons made. The transitional stage (PN3 vs. PW1) had the largest number (115) of differentially expressed miRNA. Inhibition of miR-29a in satellite cell culture increased (p < 0.05) cell proliferation and differentiation capacity. Characterization of the miRNA transcriptome provides valuable insights into the miRNA involved in muscle fiber hypertrophy and the potential importance of the transitional period.

Integrated Transcriptome Analysis of miRNAs and mRNAs in the Skeletal Muscle of Wuranke Sheep

“…Muscle fibers are formed prenatally in sheep, especially during mid-gestation [29]. In contrast, their postnatal muscle growth largely relies on muscle fiber hypertrophy [30]. The growth rate of sheep is extremely rapid between birth and six months of age.…”

Emerging perspectives in the gut–muscle axis: The gut microbiota and its metabolites as important modulators of meat quality

“…The development of skeletal muscle can be generally separated into two distinct periods (Picard & Gagaoua, 2020 ): hyperplasia (increase in the fibre number) and hypertrophy (increase in the fibre diameter). Although fibre number is strongly determined during embryonic development, there is overwhelming evidence that muscle growth not only changes the fibre size to adapt to alterations in muscle function and metabolism but also changes the fibre type composition regardless of animal species, including cattle (Wegner et al., 2000 ), pigs (Qian et al., 2015 ), chickens (Yu et al., 2021 ) and lamb (Greene et al., 2022 ). The plasticity of muscle fibres is regulated by an interaction between the host genotype and environment.…”

The Function and Regulation Mechanism of Non-Coding RNAs in Muscle Development

“…miR-23a promotes myogenic differentiation of fetal bovine skeletal muscle-derived progenitor cells by targeting the MyoD family inhibitor structural domain-containing (MDFIC) genes [66]. miR-2425-5p targets the 3 -UTR of RAD9 homolog A (RAD9A) and myogenesis (MYOG) to promote proliferation and inhibit differentiation [67] in sheep and goats, including miR-181a, miR-29a, miR-99b-3p, and miR-27a-3p [69][70][71][72] and in rabbits and pigs, including miR-194-5p and miR-22, respectively [80,81]. The specific mechanisms of action of these miRNAs will not be elaborated.…”