A calcineurin-NFATc3-dependent pathway regulates skeletal muscle differentiation and slow myosin heavy-chain expression
A calcineurin-NFATc3-dependent pathway regulates skeletal muscle differentiation and slow myosin heavy-chain expression
复制标题
DOI：
10.1128/mcb.20.17.6600-6611.2000
复制
发表时间：
2000-09-01
影响因子：
5.3
通讯作者：
Molkentin, JD
中科院分区：
文献类型：
--
作者：
Delling, U;Tureckova, J;Molkentin, JD
骨骼肌细胞分化和成熟为功能纤维在很大程度上是由诱导信号协调的，这些诱导信号通过离散的细胞内信号转导途径发挥作用。最近，钙激活磷酸酶钙调神经磷酸酶(PP2B)和转录因子家族NFAT被认为参与了心肌细胞肥大的调节和纤维类人猿的特异性。在这里，我们分析了胰岛素样生长因子-1(IGF-1)-钙调神经磷酸酶-NFAT信号转导通路导致心肌细胞分化和纤维类型特异性的细胞内机制。我们证明，在培养的C2C12细胞中，钙调神经磷酸酶的活性在肌源性分化的启动过程中一过性地增加，并且这种增加与NFATc3核移位有关。腺病毒介导的钙调神经磷酸酶激活蛋白(AdCnA)基因转移促进C2C12和SO18心肌细胞的分化，而腺病毒介导的非竞争性钙调神经磷酸酶抑制肽(CaN或Delta AKAP79)的基因转移则抑制分化。AdCnA感染也足以挽救IGF缺失的成肌细胞系的肌细胞分化。利用10T1/2细胞，我们证明，无论是钙调神经磷酸酶还是NFATc3共转染，MyoD导向的肌肉发生都显著增强，而钙调神经磷酸酶抑制肽(CaN)则阻止分化。由钙调神经磷酸酶而不是NFATc3诱导的成肌分化增强优先表达慢的肌球蛋白重链，而通过丝裂原激活的蛋白激酶6(MKK6)增强的分化促进快速肌球蛋白重链的表达。这些数据表明，涉及IGF-钙调神经磷酸酶-NFATc3的信号通路促进了肌源性分化，而钙调神经磷酸酶通过其他因素作用于促进慢纤维类型的程序。
The differentiation and maturation of skeletal muscle cells into functional fibers is coordinated largely by inductive signals which act through discrete intracellular signal transduction pathways. Recently, the calcium-activated phosphatase calcineurin (PP2B) and the family of transcription factors known as NFAT have been implicated in the regulation of myocyte hypertrophy and fiber ape specificity. Here we present an analysis of the intracellular mechanisms which underlie myocyte differentiation and fiber type specificity due to an insulin-like growth factor 1 (IGF-1)-calcineurin-NFAT signal transduction pathway. We demonstrate that calcineurin enzymatic activity is transiently increased during the initiation of myogenic differentiation in cultured C2C12 cells and that this increase is associated with NFATc3 nuclear translocation. Adenovirus-mediated gene transfer of an activated calcineurin protein (AdCnA) potentiates C2C12 and So18 myocyte differentiation, while adenovirus-mediated gene transfer of noncompetitive calcineurin-inhibitory peptides (cain or Delta AKAP79) attenuates differentiation. AdCnA infection was also sufficient to rescue myocyte differentiation in an IGF-depleted myoblast cell line. Using 10T1/2 cells, we demonstrate that MyoD-directed myogenesis is dramatically enhanced by either calcineurin or NFATc3 cotransfection, while a calcineurin inhibitory peptide (cain) blocks differentiation. Enhanced myogenic differentiation directed by calcineurin, but not NFATc3, preferentially specifies slow myosin heavy-chain expression, while enhanced differentiation through mitogen-activated protein kinase kinase 6 (MKK6) promotes fast myosin heavy-chain expression. These data indicate that a signaling pathway involving IGF-calcineurin-NFATc3 enhances myogenic differentiation whereas calcineurin acts through other factors to promote the slow fiber type program.