Enhanced small neutral but not branched chain amino acid transport after epigenetic sodium coupled neutral amino acid transporter-2 (SNAT2) cDNA expression in myoblasts.
Enhanced small neutral but not branched chain amino acid transport after epigenetic sodium coupled neutral amino acid transporter-2 (SNAT2) cDNA expression in myoblasts.
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成肌细胞中表观遗传钠偶联中性氨基酸转运蛋白 2 (SNAT2) cDNA 表达后增强小中性而非支链氨基酸转运。
DOI：
10.1002/jcsm.12707
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发表时间：
2021-06
期刊：
影响因子：
--
通讯作者：
Powell PP
中科院分区：
文献类型：
--
作者：
Pearson T;Wendowski O;Powell PP
骨骼肌的质量和功能部分由氨基酸的供应维持，氨基酸运输的改变是脆弱的重要原因，可导致独立性随着年龄的增长而降低，创伤恢复缓慢。SLC38A2基因家族编码的钠偶联中性氨基酸转运体(SNAT-2)系统产生一个506个氨基酸的56 kDa蛋白质，是骨骼肌中重要的氨基酸转运体。衰老与SNAT2转运蛋白表达减少有关。在本研究中，我们使用了C2C12细胞系，利用成肌细胞和分化为肌管的细胞。我们研究了SNAT2 DNA的表达是否会提高细胞内氨基酸水平，并增加它们对蛋白质合成的利用率。在对照成肌细胞和肌管中，我们发现SNAT2在肌管中的表达显著低于成肌细胞(6.5倍下降，n=0.04，P<0.05)。转染SNAT2-EGFP基因后，C2C12成肌细胞的核周点状SNAT2-EGFP表达显著增加，这种表达持续存在，并在分化为肌管后具有更强的细胞质。有趣的是，转基因细胞对激素5α-双氢睾酮的反应明显增强(DHT4.5nM，提高1.6倍，n=0.03，P=0.04)。饥饿显著增加了氨基酸C14-MeAIB的转运(1.7×，n=0.05)，表明SNAT2的功能增强。用高浓度的MeAIB(3.3或5 mM)抑制SNAT2可显著抑制L型氨基酸转运体对C14-异亮氨酸的转运(LAT2，分别为52.8%和77%，n=3/组，P<0.05)。然而，在SNAT2-EGFP细胞中可检测到的C14-异亮氨酸的LAT2转运在DHT(4.5 NM)暴露后并没有增加。这表明，在成肌细胞中，少量氨基酸的可获得性不是LAT2功能的速率限制。总体而言，这些数据表明，SNAT2-EGFP的表达在饥饿和生理水平的DHT处理后增强了其功能。在与氨基酸转运改变相关的病理条件下，肌肉细胞中SNAT2的增强表达提供了一个可行的表观遗传学靶点。
Skeletal muscle mass and function are partly maintained by the supply of amino acids, altered amino acid transport is an important cause of frailty that can lead to decreased independence with increasing age and slow trauma recovery. The system‐A sodium coupled neutral amino acid transporter (SNAT)‐2 coded by gene family SLC38A2 generates a 506 amino acid 56 kDa protein that is an important transporter of amino acids in skeletal muscle. Ageing is associated with a decrease in expression of SNAT2 transporters. In this study, we used the C2C12 cell line, using myoblast cells and cells differentiated into myotubes. We investigated if the expression of SNAT2 DNA would enhance intracellular amino acid levels and increase their availability for protein synthesis. In control myoblasts and myotubes, we found significantly decreased expression of SNAT2 (6.5× decrease, n = 4 per group, P < 0.05) in myotubes than found in myoblasts. After transfection with a SNAT2‐eGFP cDNA plasmid, C2C12 myoblasts significantly increased perinuclear punctate SNAT2‐eGFP expression that persisted and was more cytoplasmic after differentiation into myotubes. Interestingly, transfected cells were significantly more responsive to the hormone 5α‐dihydrotestosterone (DHT, 4.5 nM, by 1.6×, n = 3 per group, P < 0.04). Starvation significantly enhanced the amino acid C14‐MeAIB transport (1.7×, n = 3 per group, P < 0.05) indicating increased function of SNAT2. Inhibiting SNAT2 with high concentrations of MeAIB (3.3 or 5 mM) significantly reduced C14‐Isoleucine transport by L‐type amino acid transporter (LAT2, 52.8% and 77%, respectively, n = 3 per group, P < 0.05). However, there was no increase in the LAT2 transport of C14‐isoleucine detectable in SNAT2‐eGFP transfected cells after DHT (4.5 nM) exposure. This indicated that small amino acid availability was not rate limiting to LAT2 function in myoblasts. Overall, these data show that transfection of SNAT2‐eGFP expression enhanced its function following starvation and treatment with physiological levels of DHT. Enhanced SNAT2 expression in muscle cells offers a viable epigenetic target in pathological conditions associated with altered amino acid transport.
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影响因子：
5.3
作者：
HOLLOSZY, JO;CHEN, M;YOUNG, JC
通讯作者：
YOUNG, JC
DOI：
10.1067/mlc.2001.113504
发表时间：
2001-04-01
期刊：
JOURNAL OF LABORATORY AND CLINICAL MEDICINE
影响因子：
--
作者：
Morley, JE;Baumgartner, RN;Nair, KS
通讯作者：
Nair, KS
影响因子：
56.9
作者：
BARR, E;LEIDEN, JM
通讯作者：
LEIDEN, JM
影响因子：
2.7
作者：
Lawson, MA;Purslow, PP
通讯作者：
Purslow, PP
影响因子：
3.5
作者：
Kashiwagi, Hitoshi;Yamazaki, Kojiro;Sugawara, Mitsuru
通讯作者：
Sugawara, Mitsuru