1a,25(OH)2D3-dependent modulation of Akt in proliferating and differentiating C2C12 skeletal muscle cells
1a,25(OH)2D3-dependent modulation of Akt in proliferating and differentiating C2C12 skeletal muscle cells
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DOI：
10.1002/jcb.23444
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发表时间：
2012-04-01
影响因子：
4
通讯作者：
Boland, Ricardo L.
中科院分区：
文献类型：
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作者：
Buitrago, Claudia G.;Arango, Nadia S.;Boland, Ricardo L.
我们之前报道了1a，25-二羟基维生素D3 [1a，25(OH)2D3]通过激活骨骼肌细胞系C2C12中的Src和MAPKs诱导非转录快速反应。在本研究中，我们研究了在C2C12细胞增殖阶段（成肌细胞）和早期分化阶段，类固醇激素对Akt的调节。在增殖细胞中，1a,25(OH)2D3通过磷酸化Ser473蛋白激活Akt，并以时间依赖性的方式激活（560?min）。当用甲基- β -环糊精预处理这些细胞以破坏小泡微域时，激素诱导的Akt激活被抑制。通过siRNA沉默caveolin-1表达也获得了类似的结果，进一步表明激素对细胞膜小窝的作用是下游信号传递所必需的。PI3K和p38 MAPK参与成肌细胞中Akt的1a，25(OH)2D3活化，而不是ERK1/2。p38 MAPK参与Akt被激素磷酸化可能是通过MAPK激活的蛋白激酶2 （MK2）发生的，MK2被类固醇激活。此外，使用抑制Src表达的抑制剂PP2和反义寡脱氧核苷酸证实Src参与了1a，25(OH)2D3对Akt的磷酸化。我们还观察到PI3K参与激素诱导的增殖。在C2C12细胞分化1a的早期阶段，25(OH)2D3也增加Akt磷酸化并激活Src。与此相关的是，Src和PI3K参与Akt激活，MHC和肌原蛋白的表达增加了1a，25(OH)2D3。总之，这些数据表明，1a,25(OH)2D3通过Src、PI3K和p38 MAPK上调Akt，刺激C2C12细胞的肌生成。j .细胞。中国生物医学工程学报，2012,31(2):481 - 481。(c) 2011 Wiley期刊公司
We previously reported that 1a,25-dihydroxy-vitamin D3 [1a,25(OH)2D3] induces non-transcriptional rapid responses through activation of Src and MAPKs in the skeletal muscle cell line C2C12. In the present study we investigated the modulation of Akt by the secosteroid hormone in C2C12 cells at proliferative stage (myoblasts) and at early differentiation stage. In proliferating cells, 1a,25(OH)2D3 activates Akt by phosphorylation in Ser473 in a time-dependent manner (560?min). When these cells were pretreated with methyl-beta-cyclodextrin to disrupt caveolae microdomains, hormone-induced activation of Akt was suppressed. Similar results were obtained by siRNA silencing of caveolin-1 expression, further indicating that hormone effects on cell membrane caveolae are required for downstream signaling. PI3K and p38 MAPK, but not ERK1/2, participate in 1a,25(OH)2D3 activation of Akt in myoblasts. The involvement of p38 MAPK in Akt phosphorylation by the hormone probably occurs through MAPK-activated protein kinase 2 (MK2), which is activated by the steroid. In addition, the participation of Src in Akt phosphorylation by 1a,25(OH)2D3 was demonstrated using the inhibitor PP2 and antisense oligodeoxynucleotides that suppress Src expression. We also observed that PI3K participates in hormone-induced proliferation. During the early phase of C2C12 cell differentiation 1a,25(OH)2D3 also increases Akt phosphorylation and activates Src. Of relevance, Src and PI3K are involved in Akt activation and in MHC and myogenin increased expression by 1a,25(OH)2D3. Altogether, these data suggest that 1a,25(OH)2D3 upregulates Akt through Src, PI3K, and p38 MAPK to stimulate myogenesis in C2C12 cells. J. Cell. Biochem. 113: 11701181, 2012. (c) 2011 Wiley Periodicals, Inc.