Ryan Zachary C, Craig Theodore A, Folmes Clifford D, Wang Xuewei, Lanza Ian R, Schaible Niccole S, Salisbury Jeffrey L, Nair K Sreekumaran, Terzic Andre, Sieck Gary C, Kumar Rajiv
From the Departments of Medicine.
Health Sciences Research.
J Biol Chem. 2016 Jan 15;291(3):1514-28. doi: 10.1074/jbc.M115.684399. Epub 2015 Nov 24.
Muscle weakness and myopathy are observed in vitamin D deficiency and chronic renal failure, where concentrations of the active vitamin D3 metabolite, 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3), are low. To evaluate the mechanism of action of 1α,25(OH)2D3 in skeletal muscle, we examined mitochondrial oxygen consumption, dynamics, and biogenesis and changes in expression of nuclear genes encoding mitochondrial proteins in human skeletal muscle cells following treatment with 1α,25(OH)2D3. The mitochondrial oxygen consumption rate (OCR) increased in 1α,25(OH)2D3-treated cells. Vitamin D3 metabolites lacking a 1α-hydroxyl group (vitamin D3, 25-hydroxyvitamin D3, and 24R,25-dihydroxyvitamin D3) decreased or failed to increase OCR. 1α-Hydroxyvitamin D3 did not increase OCR. In 1α,25(OH)2D3-treated cells, mitochondrial volume and branching and expression of the pro-fusion protein OPA1 (optic atrophy 1) increased, whereas expression of the pro-fission proteins Fis1 (fission 1) and Drp1 (dynamin 1-like) decreased. Phosphorylated pyruvate dehydrogenase (PDH) (Ser-293) and PDH kinase 4 (PDK4) decreased in 1α,25(OH)2D3-treated cells. There was a trend to increased PDH activity in 1α,25(OH)2D3-treated cells (p = 0.09). 83 nuclear mRNAs encoding mitochondrial proteins were changed following 1α,25(OH)2D3 treatment; notably, PDK4 mRNA decreased, and PDP2 mRNA increased. MYC, MAPK13, and EPAS1 mRNAs, which encode proteins that regulate mitochondrial biogenesis, were increased following 1α,25(OH)2D3 treatment. Vitamin D receptor-dependent changes in the expression of 1947 mRNAs encoding proteins involved in muscle contraction, focal adhesion, integrin, JAK/STAT, MAPK, growth factor, and p53 signaling pathways were observed following 1α,25(OH)2D3 treatment. Five micro-RNAs were induced or repressed by 1α,25(OH)2D3. 1α,25(OH)2D3 regulates mitochondrial function, dynamics, and enzyme function, which are likely to influence muscle strength.
在维生素D缺乏和慢性肾衰竭患者中可观察到肌肉无力和肌病，这些患者体内活性维生素D3代谢产物1α,25 - 二羟基维生素D3（1α,25(OH)2D3）的浓度较低。为评估1α,25(OH)2D3在骨骼肌中的作用机制，我们检测了人骨骼肌细胞在用1α,25(OH)2D3处理后线粒体的氧消耗、动态变化、生物发生以及编码线粒体蛋白的核基因表达的变化。在用1α,25(OH)2D3处理的细胞中，线粒体氧消耗率（OCR）增加。缺乏1α - 羟基的维生素D3代谢产物（维生素D3、25 - 羟基维生素D3和24R,25 - 二羟基维生素D3）使OCR降低或未能使其增加。1α - 羟基维生素D3未增加OCR。在1α,25(OH)2D3处理的细胞中，线粒体体积、分支以及促融合蛋白OPA1（视神经萎缩蛋白1）的表达增加，而促分裂蛋白Fis1（分裂蛋白1）和Drp1（动力蛋白1样蛋白）的表达降低。在1α,25(OH)2D3处理的细胞中，磷酸化丙酮酸脱氢酶（PDH）（Ser - 293）和PDH激酶4（PDK4）减少。在1α,25(OH)2D3处理的细胞中，PDH活性有增加的趋势（p = 0.09）。在用1α,25(OH)2D3处理后，83种编码线粒体蛋白的核mRNA发生了变化；值得注意的是，PDK4 mRNA减少，而PDP2 mRNA增加。在用1α,25(OH)2D3处理后，编码调节线粒体生物发生的蛋白的MYC、MAPK13和EPAS1 mRNA增加。在用1α,25(OH)2D3处理后，观察到1947种编码参与肌肉收缩、粘着斑、整合素、JAK/STAT、MAPK、生长因子和p53信号通路相关蛋白的mRNA的表达发生了维生素D受体依赖性变化。1α,25(OH)2D3诱导或抑制了5种微小RNA。1α,25(OH)2D3调节线粒体功能、动态变化和酶功能，这可能会影响肌肉力量。
