Identification of human skeletal muscle miRNA related to strength by high-throughput sequencing

Abstract

The loss of muscle size, strength, and quality with aging is a major determinant of morbidity and mortality in the elderly. The regulatory pathways that impact the muscle phenotype include the translational regulation maintained by microRNAs (miRNA). Yet the miRNAs that are expressed in human skeletal muscle and relationship to muscle size, strength, and quality are unknown. Using next-generation sequencing, we selected the 50 most abundantly expressed miRNAs and then analyzed them in vastus lateralis muscle, obtained by biopsy from middle-aged males ( n = 48; 50.0 ± 4.3 yr). Isokinetic strength testing and midthigh computed tomography was undertaken for muscle phenotype analysis. Muscle attenuation was measured by computerized tomography and is inversely proportional to myofiber lipid content. miR-486-5p accounted for 21% of total miR sequence reads, with miR-10b-5p, miR-133a-3p, and miR-22-3p accounting for a further 15, 12, and 10%, respectively. Isokinetic knee extension strength and muscle cross-sectional area were positively correlated with miR-100-5p, miR-99b-5p, and miR-191-5p expression. Muscle attenuation was negatively correlated to let-7f-5p, miR-30d-5p, and miR-125b-5p expression. In silico analysis implicates miRNAs related to strength and muscle size in the regulation of mammalian target of rapamycin, while miRNAs related to muscle attenuation may have potential roles regulating the transforming growth factor-β/SMAD3 pathway.

Whey Protein Supplementation Post Resistance Exercise in Elderly Men Induces Changes in Muscle miRNA's Compared to Resistance Exercise Alone

“…The relationship explained ~49% of model variance. This finding is consistent with several studies in rested middle aged men (24, 25), healthy controls vs. competitive powerlifters (23), and the patterns seen with limb immobilization (30), as well as following overload induced hypertrophy via surgical ablation in rats (39). From our previous work, miR-133a in combination with miR-146a explained ~33% and ~34%, respectively, of participant variability in whole body and leg lean mass, respectively.…”

Increased expression of the mitochondrial derived peptide, MOTS-c, in skeletal muscle of healthy aging men is associated with myofiber composition

“…Primer sequences used are listed in Supplementary Table 3, and for mitochondrial (mtDNA) to nuclear (nDNA) ratio primers were used to MTND4 and 18S rRNA. For small RNA assays, 50 ng of fractioned RNA was converted to cDNA using TaqMan® microRNA RT kit #4366596 (Life Technologies, Carlsbad, CA) and a multiplexed approach [49] was utilized with specific TaqMan small RNA assays (Life Technologies, Carlsbad, CA) for MOTS-c (designed using Custom TaqMan® Small RNA Assay Design Tool against MOTS-c mtDNA sequence), RNU44 (assay ID: 001094) and RNU48 (assay ID: 001006) primers as per the manufactures instruction and as described previously [50]. The expression of MOTS-c mRNA was normalized to the geomean RNU44 and RNU48 using the ∆∆Ct method.…”

Aging‐associated skeletal muscle defects in HER2/Neu transgenic mammary tumour model

“…Aging-associated changes in circulating miR-486 levels are also reported. 46 miR-486, which is enriched in the skeletal muscle and accounts for 21% of total miRNA sequence reads in the skeletal muscle, is an integral part of a myogenesis signalling network that involves Pax7, MyoD, myostatin, and NF-κB, 47,48 and aging-associated inflammatory changes likely disrupt this axis. Systemic inflammation due to Neu+ tumours may have accelerated skeletal muscle aging process.…”