PKA-dependent and independent cAMP signaling in 3T3-L1 fibroblasts differentiation
PKA-dependent and independent cAMP signaling in 3T3-L1 fibroblasts differentiation
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DOI：
10.1016/j.mce.2008.10.023
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发表时间：
2009-01-27
影响因子：
4.1
通讯作者：
Vila, Maria del C.
中科院分区：
文献类型：
--
作者：
Martini, Claudia N.;Plaza, Maria V.;Vila, Maria del C.
胰岛素、地塞米松和甲基异丁基黄嘌呤（MIX）的组合刺激3 T3-L1成纤维细胞中的脂肪生成。有丝分裂克隆扩增（MCE）先于3 T3-L1成纤维细胞分化为脂肪细胞。MIX增加cAMP含量，cAMP是蛋白激酶A（PKA）的激活剂。然而，也已经描述了不依赖PKA的cAMP信号传导。本文发现PKA抑制剂H89能阻断3 T-3-L1成纤维细胞的MCE，但不能阻断3 T-3-L1成纤维细胞分化。一致的是，MCE没有发生在分化混合物中的MIX的情况下，但恢复PKA的催化亚基的过表达。此外，用PKA的adominant-negative突变体转染3 T3-L1成纤维细胞抑制MCE。另一方面，当MIX不存在于分化混合物中时，3 T3-L1成纤维细胞向脂肪细胞的分化不会发生，并且不能通过PKA的催化亚基的过表达来恢复。通过添加二丁酰-cAMP（db-cAMP）或8 CPT-2 Me-cAMP来恢复分化。后者激活cAMP-EPAC但不激活PKA信号传导。这些结果表明，3 T3-L1成纤维细胞分化为脂肪细胞需要cAMP-PKA非依赖性信号传导，并且通过cAMP-PKA的MIX信号传导对于MCE是必需的，尽管MCE对于脂肪形成不是必需的。(c)2008爱思唯尔爱尔兰有限公司保留所有权利。
Adipogenesis is stimulated in 3T3-L1 fibroblast by a combination of insulin, dexamethasone, and methylisobutylxanthine (MIX). Mitotic clonal expansion (MCE) precedes differentiation of 3T3-L1 fibroblast to adipocytes. MIX increases cAMP content, which is the activator of protein kinase A (PKA). However, PKA-independent cAMP signaling has also been described. In this paper, it was found that H89, an inhibitor of PKA, was able to block MCE but not differentiation of 3T-3-L1 fibroblast. Consistently, MCE did not occur in the absence of MIX in the differentiation mixture but was recovered by overexpression of a catalytic subunit of PKA. In addition, the transfection of 3T3-L1 fibroblast with adominant-negative mutant of PKA inhibited MCE. On the other hand, differentiation of 3T3-L1 fibroblast to adipocytes did not occur when MIX was not present in the differentiation mixture and it could not be recovered by overexpression of a catalytic subunit of PKA. Differentiation was restored by addition of either dibutyryl-cAMP (db-cAMP) or 8 CPT-2 Me-cAMP. The latter activates cAMP-EPAC but not PKA signaling. These results indicate that cAMP-PKA-independent signaling, is required for 3T3-L1 fibroblasts differentiation to adipocytes and MIX signaling through cAMP-PKA is necessary for MCE, although MCE is not essential for adipogenesis. (c) 2008 Elsevier Ireland Ltd. All rights reserved.