کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10759520 1050425 2013 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Cessation of cyclic stretch induces atrophy of C2C12 myotubes
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Cessation of cyclic stretch induces atrophy of C2C12 myotubes
چکیده انگلیسی
Cyclic stretch of differentiated myotubes mimics the loading pattern of mature skeletal muscle. We tested a cell culture model of disuse atrophy by the cessation of repetitive bouts of cyclic stretch in differentiated C2C12 myotubes. Myotubes were subjected to cyclic strain (12%, 0.7 Hz, 1 h/d) on collagen-I-coated Bioflex plates using a computer-controlled vacuum stretch apparatus (Flexcell Int.) for 2 (2dSTR) or 5 (5dSTR) consecutive days. Control cultures were maintained in the Bioflex plates without cyclic stretch for 2 d or 5 d. Additionally, some cultures were stretched for 2 d followed by cessation of stretch for 3 d (2dSTR3dCES). Cyclic stretching (5dSTR) increased myotube diameter and overall myotube area by ∼2-fold (P < 0.05) compared to non-stretched controls, while cessation of stretch (2dSTR3dCES) resulted in ∼80% smaller myotubes than 5dSTR cells, and 40-50% smaller than non-stretched controls (P < 0.05). Further, the calpain-dependent cleavage products of αII-spectrin (150 kDa) and talin increased (3.5-fold and 2.2-fold, respectively; P < 0.05) in 2dSTR3dCES myotubes, compared to non-stretched controls. The 1 h cyclic stretching protocol acutely increased the phosphorylation of Akt (+4.5-fold; P < 0.05) and its downstream targets, FOXO3a (+4.2-fold; P < 0.05) and GSK-3β (+1.8-fold; P < 0.05), which returned to baseline by 48 h after cessation of stretch. Additionally, nitric oxide production increased during stretch and co-treatment with the NOS inhibitor, l-NAME, inhibited the effects of stretch and cessation of stretch. We conclude that cessation of cyclic stretching causes myotube atrophy by activating calpains and decreasing activation of Akt. Stretch-induced myotube growth, as well as activation of atrophy signaling with cessation of stretch, are dependent on NOS activity.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochemical and Biophysical Research Communications - Volume 434, Issue 2, 3 May 2013, Pages 316-321
نویسندگان
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