Transforming growth factor-β1 regulates fibronectin isoform expression and splicing factor SRp40 expression during ATDC5 chondrogenic maturation
Transforming growth factor-β1 regulates fibronectin isoform expression and splicing factor SRp40 expression during ATDC5 chondrogenic maturation
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DOI：
10.1016/j.yexcr.2007.01.028
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发表时间：
2007-05-01
影响因子：
3.7
通讯作者：
Hickok, Noreen J.
中科院分区：
文献类型：
--
作者：
Han, Fei;Gilbert, James R.;Hickok, Noreen J.
纤维连接蛋白（FN）异构体的表达在软骨细胞发育和成熟过程中发生改变，软骨倾向于表达FN异构体，包括II型重复的额外结构域B (EDB)，但不包括额外结构域A （EDA）。我们和其他人假设FN mrna的调节剪接对于软骨形成的进展是必要的。为了验证这一点，我们用转化生长因子- β 1处理了软骨形成前细胞系ATDC5，该因子已被证明可以调节EDA和EDB外显子的表达，以及软骨细胞成熟的晚期标志物；在不影响细胞增殖的情况下，它也略微加速了硫酸盐蛋白聚糖基质的早期获取。当用tgf - β 1治疗软骨细胞时，EDA外显子在任何时候都被优先排除，而EDB外显子在早期相对减少。这种受调控的FN选择性剪接与SRp40的选择性剪接相关，SRp40是一种促进EDA外显子包含的剪接因子。为了确定SRp40亚型的过表达是否改变了FN和FN EDA组织，编码这些亚型的cdna在ATDCS细胞中过表达。长型SRp40的过表达产生类似于tgf - β 1处理的FN组织；而过表达短形式的SRp40（促进EDA的包含）则增加了长而粗的FN原纤维的形成。因此，我们得出结论，tgf - β 1对软骨形成过程中FN剪接的影响可能在很大程度上取决于其对SRp40异构体表达的影响。(c) 2007爱思唯尔公司版权所有。
Fibronectin (FN) isoform expression is altered during chondrocyte commitment and maturation, with cartilage favoring expression of FN isoforms that includes the type II repeat extra domain B (EDB) but excludes extra domain A (EDA). We and others have hypothesized that the regulated splicing of FN mRNAs is necessary for the progression of chondrogenesis. To test this, we treated the pre-chondrogenic cell line ATDC5 with transforming growth factor-beta 1, which has been shown to modulate expression of the EDA and EDB exons, as well as the late markers of chondrocyte maturation; it also slightly accelerates the early acquisition of a sulfated proteoglycan matrix without affecting cell proliferation. When chondrocytes are treated with TGF-beta 1, the EDA exon is preferentially excluded at all times whereas the EDB exon is relatively depleted at early times. This regulated alternative splicing of FN correlates with the regulation of alternative splicing of SRp40, a splicing factor facilitating inclusion of the EDA exon. To determine if overexpression of the SRp40 isoforms altered FN and FN EDA organization, cDNAs encoding these isoforms were overexpressed in ATDCS cells. Overexpression of the long-form of SRp40 yielded an FN organization similar to TGF-beta 1 treatment; whereas overexpression of the short form of SRp40 (which facilitates EDA inclusion) increased formation of long-thick FN fibrils. Therefore, we conclude that the effects of TGF-beta 1 on FN splicing during chondrogenesis may be largely dependent on its effect on SRp40 isoform expression. (c) 2007 Elsevier Inc. All rights reserved.