Intake of branched-chain amino acids influences the levels of MAFbx mRNA and MuRF-1 total protein in resting and exercising human muscle
Intake of branched-chain amino acids influences the levels of MAFbx mRNA and MuRF-1 total protein in resting and exercising human muscle
复制标题
DOI：
10.1152/ajpendo.00353.2011
复制
发表时间：
2012-03-01
影响因子：
5.1
通讯作者：
Blomstrand, Eva
中科院分区：
文献类型：
--
作者：
Borgenvik, Marcus;Apro, William;Blomstrand, Eva
Borgenvik M，AproW，Blomstrand E.支链氨基酸的摄入影响静息和运动人体肌肉中MAFbx mRNA和MURF-1总蛋白的水平。AM J生理学内分泌代谢酶302：E510-E521,2012。2011年11月29日首次出版；DOI：10.1152/ajpendo.00353.2011。-抗阻运动和氨基酸是影响肌肉蛋白质周转的两个主要因素。在这里，我们研究了抗阻运动和支链氨基酸(BCAA)单独和组合对人类骨骼肌合成代谢和分解代谢基因表达的影响。7名受试者在随机补充支链氨基酸或调味水的情况下进行了两次单侧腿部按压练习。在运动前和运动后重复采集静息和运动腿股外侧肌的活组织标本，以确定mRNA水平、蛋白质磷酸化水平和氨基酸浓度。摄入支链氨基酸后，安静腿和运动腿的MAFbx mRNA分别减少了30%和50%(P<；0.05)。在安慰剂和支链氨基酸条件下，运动腿的Murf-1mRNA水平分别增加了2倍和3倍(P<；0.05)，而Murf-1总蛋白仅在安慰剂条件下增加了20%(P<；0.05)。在恢复早期补充支链氨基酸后，p70(S6K)的磷酸化水平显著增加(接近2倍；P<；0.05)，而调节mTOR活性的基因表达不受支链氨基酸的影响。在服用安慰剂的情况下，肌肉的苯丙氨酸和酪氨酸水平在恢复过程中降低了(13-17%)(P<；0.05)，在静息和运动肌肉中补充支链氨基酸后，降低的程度更大(32-43%；P<；0.05)。总之，摄入支链氨基酸降低了MAFbx mRNA，并阻止了运动诱导的静息和运动腿MURF-1总蛋白的增加。此外，阻力运动对MAFbx和Murf-1mRNA表达的影响也不同，这表明这两种泛素连接酶既有共同的调节，也有不同的调节。
Borgenvik M, Apro W, Blomstrand E. Intake of branched-chain amino acids influences the levels of MAFbx mRNA and MuRF-1 total protein in resting and exercising human muscle. Am J Physiol Endocrinol Metab 302: E510-E521, 2012. First published November 29, 2011; doi:10.1152/ajpendo.00353.2011.-Resistance exercise and amino acids are two major factors that influence muscle protein turnover. Here, we examined the effects of resistance exercise and branched-chain amino acids (BCAA), individually and in combination, on the expression of anabolic and catabolic genes in human skeletal muscle. Seven subjects performed two sessions of unilateral leg press exercise with randomized supplementation with BCAA or flavored water. Biopsies were collected from the vastus lateralis muscle of both the resting and exercising legs before and repeatedly after exercise to determine levels of mRNA, protein phosphorylation, and amino acid concentrations. Intake of BCAA reduced (P < 0.05) MAFbx mRNA by 30 and 50% in the resting and exercising legs, respectively. The level of MuRF-1 mRNA was elevated (P < 0.05) in the exercising leg two- and threefold under the placebo and BCAA conditions, respectively, whereas MuRF-1 total protein increased by 20% (P < 0.05) only in the placebo condition. Phosphorylation of p70(S6k) increased to a larger extent (similar to 2-fold; P < 0.05) in the early recovery period with BCAA supplementation, whereas the expression of genes regulating mTOR activity was not influenced by BCAA. Muscle levels of phenylalanine and tyrosine were reduced (13-17%) throughout recovery (P < 0.05) in the placebo condition and to a greater extent (32-43%; P < 0.05) following BCAA supplementation in both resting and exercising muscle. In conclusion, BCAA ingestion reduced MAFbx mRNA and prevented the exercise-induced increase in MuRF-1 total protein in both resting and exercising leg. Furthermore, resistance exercise differently influenced MAFbx and MuRF-1 mRNA expression, suggesting both common and divergent regulation of these two ubiquitin ligases.