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Expression of skeletal muscle miRNA are unaltered during 14 days of bed rest but decrease following 7 days of reloading in middle‐aged adults
Author(s) -
ArentsonLantz Emily J,
Lamon Séverine,
Fry Christopher S,
English Kirk L,
PaddonJones Doug
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.721.1
Subject(s) - muscle atrophy , microrna , bed rest , rest (music) , skeletal muscle , rehabilitation , medicine , sarcopenia , anabolism , vastus lateralis muscle , immunohistochemistry , endocrinology , andrology , biology , pathology , physical therapy , genetics , gene
microRNA (miRNA) play an important role in mitigating expression of molecular pathways that govern skeletal muscle health. Bed rest accelerates the loss of muscle mass and function; however, little is known about the role that miRNA play in muscle health during inactivity and subsequent recovery. We examined the effect of 14 days of bed rest and 7 days of rehabilitation on miRNA expression, muscle atrophy and function in middle‐aged adults. Muscle biopsies were obtained from the vastus lateralis of healthy middle‐aged (average age 51.7±1 y) male and female adults (n=19) before (PreBR) and after (PostBR) 14 days of bed rest and after (Rehab) 7 days of rehabilitation for miRNA and immunohistochemical analysis. Body composition, muscle strength and aerobic capacity were assessed using iDEXA, dynamometry, and VO ‐2‐ max testing, respectively. Collective miRNA expression was screened using Firefly Bioworks multiplex assay with a custom panel of 65 candidate species. Based on prelimnary statistical analysis of multiplex assay, individual miRNA expression was confirmed using miRNA‐specific stem‐loop primers (TaqMan® microRNA assay kit) and qPCR. Expression of miR206 (1.07, 1.22, and 0.94 ± 0.16 for PreBR, PostBR, and Rehab), mir133a (1.10, 1.18, and 0.95 ± 0.05 for PreBR, PostBR, and Rehab), mir378 (1.46, 1.47, and 1.20 ± 0.05 for PreBR, PostBR, and Rehab) and let7b (0.89, 0.97 and 0.87 ± 0.05 for PreBR, PostBR, and Rehab) did not change with bed rest, but were significantly decreased following 7 days of rehabilitation. Muscle quality, relative VO 2 max (ml/min/kg), fiber cross sectional area and satellite cell number decreased during bed rest and did not return to baseline values. The precise role of miRNAs in muscle regrowth is not well understood. However, the overall pattern of response of miRNAs 206, 133a, 378 and let7‐b to rehabilitation indicate they may involved in the coordinated process to restore muscle mass and function following disuse. Support or Funding Information This research was supported by: NSBRI‐NNJ08ZSA002N, RO1 NR012973, P30 AG024832.