Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
Dev Biol. 2010 Aug 1;344(1):233-47. doi: 10.1016/j.ydbio.2010.05.004. Epub 2010 May 8.
Smad7 is a negative regulator of TGFbeta superfamily signaling. Using a three-component triple transgenic system, expression of the inhibitory Smad7 was induced via doxycycline within the NCC lineages at pre- and post-migratory stages. Consistent with its role in negatively regulating both TGFbeta and BMP signaling in vitro, induction of Smad7 within the NCC significantly suppressed phosphorylation levels of both Smad1/5/8 and Smad2/3 in vivo, resulting in subsequent loss of NCC-derived craniofacial, pharyngeal and cardiac OFT cushion cells. At the cellular level, increased cell death was observed in pharyngeal arches. However, cell proliferation and NCC-derived smooth muscle differentiation were unaltered. NCC lineage mapping demonstrated that cardiac NCC emigration and initial migration were not affected, but subsequent colonization of the OFT was significantly reduced. Induction of Smad7 in post-migratory NCC resulted in interventricular septal chamber septation defects, suggesting that TGFbeta superfamily signaling is also essential for cardiac NCC at post-migratory stages to govern normal cardiac development. Taken together, the data illustrate that tightly regulated TGFbeta superfamily signaling plays an essential role during craniofacial and cardiac NCC colonization and cell survival in vivo.
Smad7 是 TGFβ 超家族信号的负调控因子。使用三组分三重转基因系统,在 NCC 谱系的前迁移和后迁移阶段通过强力霉素诱导抑制性 Smad7 的表达。与它在体外负调控 TGFβ 和 BMP 信号的作用一致,在 NCC 中诱导 Smad7 显著抑制了体内 Smad1/5/8 和 Smad2/3 的磷酸化水平,导致随后 NCC 衍生的颅面、咽和心脏 OFT 垫细胞的丧失。在细胞水平上,观察到咽弓中的细胞死亡增加。然而,细胞增殖和 NCC 衍生的平滑肌分化没有改变。NCC 谱系标记表明心脏 NCC 的迁移和初始迁移不受影响,但随后 OFT 的定植显著减少。迁移后 NCC 中 Smad7 的诱导导致室间隔室间隔缺陷,表明 TGFβ 超家族信号在迁移后阶段对心脏 NCC 也至关重要,以控制正常的心脏发育。总之,数据表明,严格调控的 TGFβ 超家族信号在颅面和心脏 NCC 的定植和体内细胞存活中发挥着重要作用。