Immobilization leads to alterations in intracellular phosphagen and creatine transporter content in human skeletal muscle
| Autor: | Sophie Joanisse, Dan Luo, Leigh Breen, Sophie J Edwards, Molly Perkins, Yusuke Nishimura, Andrew Philp, Benoit Smeuninx, James McKendry |
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| Rok vydání: | 2020 |
| Předmět: |
medicine.medical_specialty
biology Physiology Chemistry AMPK Skeletal muscle 030209 endocrinology & metabolism Cell Biology Isometric exercise medicine.disease 03 medical and health sciences Phosphagen 0302 clinical medicine Endocrinology medicine.anatomical_structure Atrophy Internal medicine biology.protein medicine Creatine kinase Protein kinase A 030217 neurology & neurosurgery Intracellular |
| Zdroj: | American Journal of Physiology-Cell Physiology. 319:C34-C44 |
| ISSN: | 1522-1563 0363-6143 |
| Popis: | The role of dysregulated intracellular creatine (Cr) metabolism in disuse atrophy is unknown. In this study, skeletal muscle biopsy samples were obtained after 7 days of unilateral leg immobilization (IMMOB) and from the nonimmobilized control limb (CTRL) of 15 healthy men (23.1 ± 3.5 yr). Samples were analyzed for fiber type cross-sectional area (CSA) and creatine transporter (CreaT) at the cell membrane periphery (MEM) or intracellular (INT) areas, via immunofluorescence microscopy. Creatine kinase (CK) and AMP-activated protein kinase (AMPK) were determined via immunoblot. Phosphocreatine (PCr), Cr, and ATP were measured via enzymatic analysis. Body composition and maximal isometric knee extensor strength were assessed before and after disuse. Leg strength and fat-free mass were reduced in IMMOB (~32% and 4%, respectively; P < 0.01 for both). Type II fiber CSA was smaller (~12%; P = 0.028) and intramuscular PCr lower (~13%; P = 0.015) in IMMOB vs. CTRL. CreaT protein was greater in type I fibers in both limbs ( P < 0.01). CreaT was greater in IMMOB vs. CTRL ( P < 0.01) and inversely associated with PCr concentration in both limbs ( P < 0.05). MEM CreaT was greater than INT CreaT in type I and II fibers of both limbs (~14% for both; P < 0.01 for both). Type I fiber CreaT tended to be greater in IMMOB vs. CTRL ( P = 0.074). CK was greater and phospho-to-total AMPKThr172tended to be greater,in IMMOB vs. CTRL ( P = 0.013 and 0.051, respectively). These findings suggest that modulation of intracellular Cr metabolism is an adaptive response to immobilization in young healthy skeletal muscle. |
| Databáze: | OpenAIRE |
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