Calcineurin mediates the calcium-dependent inhibition of adipocyte differentiation in 3T3-L1 cells
Calcineurin mediates the calcium-dependent inhibition of adipocyte differentiation in 3T3-L1 cells
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DOI：
10.1074/jbc.m207913200
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发表时间：
2002-12-20
影响因子：
4.8
通讯作者：
Clipstone, NA
中科院分区：
文献类型：
--
作者：
Neal, JW;Clipstone, NA
最近的研究表明，钙依赖的丝氨酸/苏氨酸磷酸酶钙调磷酸酶介导许多不同细胞类型的细胞内钙的作用。本研究探讨了钙调磷酸酶在脂肪细胞分化调控中的作用。我们发现特异性钙调磷酸酶抑制剂环孢素A和FK506克服了钙离子载体对3T3-L1前脂肪细胞分化的抗脂作用。这一发现表明，钙调磷酸酶负责介导先前记录的Ca2+依赖性脂肪生成的抑制。我们进一步证明，组成型活性钙调磷酸酶突变体的表达通过阻止原脂肪生成转录因子过氧化物酶体增殖物激活受体γ (PPARgamma)和CCAAT/增强子结合蛋白a （C/EBPalpha）的表达，有效抑制3T3-L1细胞进行脂肪细胞分化的能力。这种钙调磷酸酶介导的脂肪细胞分化阻断是通过PPARgamma1的异位表达来挽救的。最后，我们证明了用FK506或特定的钙调神经磷酸酶抑制肽抑制内源性钙调神经磷酸酶活性可以增强3T3-L1细胞对次优脂肪生成刺激的分化，这表明内源性钙调神经磷酸酶活性通常设置一个信号阈值，以对抗有效的脂肪细胞分化。总的来说，这些数据表明钙调磷酸酶作为Ca2+依赖的分子开关，通过阻止关键的促脂肪转录因子的表达，负调节脂肪细胞分化的承诺。
Recent studies have revealed that the calcium-dependent serine/threonine phosphatase calcineurin mediates the effects of intracellular calcium in many different cell types. In this study we investigated the role of calcineurin in the regulation of adipocyte differentiation. We found that the specific calcineurin inhibitors cyclosporin A and FK506 overcame the antiadipogenic effect of calcium ionophore on the differentiation of 3T3-L1 preadipocytes. This finding suggests that calcineurin is responsible for mediating the previously documented Ca2+-dependent inhibition of adipogenesis. We further demonstrate that the expression of a constitutively active calcineurin mutant potently inhibits the ability of 3T3-L1 cells to undergo adipocyte differentiation by preventing expression of the proadipogenic transcription factors peroxisome proliferator-activated receptor gamma (PPARgamma) and CCAAT/enhancer-binding protein a (C/EBPalpha). This calcineurin-mediated block in adipocyte differentiation is rescued by ectopic expression of PPARgamma1. Finally, we demonstrate that inhibition of endogenous calcineurin activity with either FK506 or a specific calcineurin inhibitory peptide enhances differentiation of 3T3-L1 cells in response to suboptimal adipogenic stimuli, suggesting that endogenous calcineurin activity normally sets a signaling threshold that antagonizes efficient adipocyte differentiation. Collectively, these data indicate that calcineurin acts as a Ca2+-dependent molecular switch that negatively regulates commitment to adipocyte differentiation by preventing the expression of critical proadipogenic transcription factors.