Blockades of mitogen-activated protein kinase and calcineurin both change fibre-type markers in skeletal muscle culture
Blockades of mitogen-activated protein kinase and calcineurin both change fibre-type markers in skeletal muscle culture
复制标题
DOI：
10.1007/s00424-002-0939-1
复制
发表时间：
2002-12-01
影响因子：
4.5
通讯作者：
Quistorff, B
中科院分区：
文献类型：
--
作者：
Higginson, J;Wackerhage, H;Quistorff, B
钙调磷酸酶或细胞外信号调节激酶（ERK 1/2）途径的激活增加体内慢纤维的百分比，表明这两种途径都可以调节骨骼肌中的纤维表型。我们研究了钙调磷酸酶阻断与环孢素A和丝裂原活化蛋白激酶激酶（MEK 1/2）阻断与U 0126对肌球蛋白重链（MHC）亚型mRNA水平和代谢酶活性的影响后，1天，3天和7天的治疗自发抽搐大鼠骨骼肌原代培养。与对照组相比，U 0126处理显著降低了MHC I β mRNA水平，显著增加了MHC IIX、MHC IIB、胚胎MHC和围产期MHC mRNA水平。此外，U 0126处理显著增加了乳酸脱氢酶、肌酸激酶、己糖激酶、苹果酸脱氢酶和β-羟酰-CoA脱氢酶活性，高于对照值，同时还观察到活性形式的丙酮酸脱氢酶百分比显著降低。钙调磷酸酶阻断显着降低MHC I β和胚胎mRNA水平低于对照组，并显着增加MHC IIX mRNA水平。环孢菌素A治疗后，乳酸脱氢酶和肌酸激酶的活性也显著增加，高于对照值。总之，结果表明，钙调磷酸酶上调慢纤维基因和抑制快纤维基因。类似地，ERK 1/2途径上调慢纤维MHC并抑制快纤维MHC亚型。然而，对酶活性的影响不是纤维类型特异性的。U 0126对活性形式丙酮酸脱氢酶百分比的影响表明ERK 1/2途径也可能参与调节该酶的磷酸化状态。
Activation of either the calcineurin or the extracellular signal-regulated kinase (ERK1/2) pathway increases the percentage of slow fibres in vivo suggesting that both pathways can regulate fibre phenotypes in skeletal muscle. We investigated the effect of calcineurin blockade with cyclosporin A and mitogen-activated protein kinase kinase (MEK1/2) blockade with U0126 upon myosin heavy chain (MHC) isoform mRNA levels and activities of metabolic enzymes after 1 day, 3 days and 7 days of treatment in primary cultures of spontaneously twitching rat skeletal muscle. U0126 treatment significantly decreased MHC Ibeta mRNA levels and significantly increased MHC IIX, MHC IIB, embryonal MHC and perinatal MHC mRNA levels when compared to control. In addition, U0126 treatment significantly increased lactate dehydrogenase, creatine kinase, hexokinase, malate dehydrogenase and beta-hydroxyacyl-CoA dehydrogenase activities above control values while a significant reduction in the percentage of pyruvate dehydrogenase in the active form was also observed. Calcineurin blockade significantly decreased both MHC Ibeta and embryonal mRNA levels below control and significantly increased MHC IIX mRNA levels. Significant increases in the activities of both lactate dehydrogenase and creatine kinase above control values were also seen following cyclosporin A treatment. In conclusion, the results suggest that calcineurin upregulates slow-fibre genes and suppresses fast-fibre genes. Similarly, the ERK1/2 pathway upregulates slow-fibre MHC and suppresses fast-fibre MHC isoforms. However, the effect on enzyme activities is not fibre-type specific. The effect of U0126 on the percentage of pyruvate dehydrogenase in the active form suggests that the ERK1/2 pathway may also be involved in regulation of the phosphorylation state of this enzyme.