Role of BMP and FGF signaling during limb development

BMP 和 FGF 信号在肢体发育过程中的作用

• 批准号: 8349034
• 负责人: MARK B LEWANDOSKI
• 金额: $ 40.3万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8349034
• 关键词: Address; Adult; Affect; Alleles; Animals; Anterior; Apoptosis; Behavior; Biology; Bone Morphogenetic Proteins; Cell Death; Cells; Cellular biology; Collaborations; Data; Development; Digit structure; Disease; Distal; Down-Regulation; Effector Cell; Elements; Embryo; Embryonic Development; Experimental Genetics; Family; Fibroblast Growth Factor; Forelimb; Gastrointestinal Neoplasms; Gene Silencing; Genes; Genetic; Goals; Growth; Heart; Hindlimb; Internet; Knock-in Mouse; Learning; Ligands; Limb Bud; Limb Development; Limb structure; Link; Malignant Neoplasms; Malignant neoplasm of prostate; Mediating; Mesenchymal; Mesenchyme; Metastatic Neoplasm to the Bone; Modeling; Molecular; Mus; Nature; Normal Cell; Osteogenesis; Pathway interactions; Pattern; Pelvic Girdle; Population; Positioning Attribute; Protein Family; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Skeleton; Structure; Surface Ectoderm; Testing; Work; beta catenin; bone morphogenetic protein receptors; human DICER1 protein; insight; interest; malignant breast neoplasm; novel; progenitor; receptor; skeletal; tumor

In prior efforts, we contributed to a large body of work that described an essential role for Fibroblast Growth Factor (FGF) signaling during limb development by examining mice lacking genes that encode FGF ligands and receptors (Lewandoski et al. 2000 Nature Genetics 28:167, Sun et al 2000 Nature Genetics 25: 6, (Verheyden et al 2005Development 132:4235). Another important signaling pathway during limb development controlled by Bone Morphogenetic Proteins (BMPs), which arguably controls all aspects of limb outgrowth: early patterning in all three axes, programmed cell death and bone formation. Therefore we have set ourselves the task to understand how BMP and FGF signaling pathways interact during limb development. Because of our general interest in limb development we have participated in a collaboration that demonstrated that Islet1-mediated activation of the beta-catenin pathway is necessary for hindlimb initiation (in press). In second collaboration it was determined that the Dicer gne product is required for the proper positioning of the hindlimb bud along the anterior -posterior body axis (Zhang, Z. et al 2011 Dev Biol 351, 254). Finally, also in a collaborative study, we determined that all of the elements of the pelvic girdle and its surrounding perichondrium are Tbx4-derived. Also, although Tbx4 is thought to be associated primarily with the hindlimb, we characterized two forelimb expression domains in a study in which we reexamined the expression of Tbx4 in detail and also traced the fates of Tbx4-expressing cells with a previously generated, but incompletely characterized, allele of Tbx4 knocked in Cre allele (Naiche A et al 2001 Dev Dyn in press). In current work, we are studying the role of BMP signaling as effectors of normal programmed cell death that occurs in mesenchymal interdigit cells, thus removing them and sculpting the final digit pattern in animals that are born without webbed limbs. In previous work produced genetic evidence for a novel model in which the surface ectoderm must receive a BMP signal, resulting in down regulation of Fgfs which in turn induces apoptosis of the underlying mesenchyme (Pajni-Underwood S. et al 2007 Development 134: 2359). Thus we demonstrated that BMPs control programmed cell death indirectly, by regulating FGF signaling. However, it is important to emphasize that this insight does not exclude a direct role for BMP signaling in controlling cell death in the developing limb. Therefore we are extended these studies by studying the role of BMP and FGF signaling in various aspects of limb development using mouse lines that express Cre in specific region of the developing limb. For example the only way to test the hypothesis that BMPs act as direct effectors of cell death is to inactivate BMPs receptors only in the lineage that undergoes cells death, without affecting FGF expression in nearby cells. We have achieved this using new Cre lines that allow Cre-mediated gene inactivation in these lineages. With these lines are asking: are BMPs are direct effectors of normal programmed cell death? If not, how is programmed cell death controlled? If so, how do BMPs achieve this endpont? In another study, we have uncovered an important node of signaling between FGFs and BMP that is essential for normal development of the limb skeleton. Our previous work, cited above, demonstrates that specific FGFs, secreted from a distal structure in the limb bud, regulate the normal outgrowth and patterning of the limb. In current work, we are generating genetic evidence that BMP signaling to the progenitor population of the skeletal elements regulates this FGF signal by controlling the expression of an FGF antagonist. This linking of the two signaling pathways is not only a unique insight into how the limb is patterned but may provide a model for how the two pathways interact in other developmental contexts or during cancer.

在先前的工作中，我们通过研究缺乏编码成纤维细胞生长因子(FGF)配体和受体的基因的小鼠，为描述成纤维细胞生长因子(FGF)信号在肢体发育过程中的关键作用的大量工作做出了贡献(Lewis等人)。2000自然遗传学28：167，Sun等人2000自然遗传学25：6(Verheyden等2005发展132：4235)。在肢体发育过程中的另一个重要信号通路是由骨形态发生蛋白(BMPs)控制的，BMPs可以控制肢体生长的方方面面：三个轴的早期构型、细胞程序性死亡和骨形成。因此，我们为自己设定的任务是了解BMP和成纤维细胞生长因子信号通路在肢体发育过程中是如何相互作用的。由于我们对肢体发育的普遍兴趣，我们参与了一项合作，证明了Islet1介导的β-连环蛋白途径的激活对于后肢的启动是必要的(在出版中)。在第二次合作中，确定了Disher Gne产品是沿着身体前后轴正确定位后肢芽所必需的(Zhang，Z.等人，2011 Dev Biol 351,254)。最后，也是在一项合作研究中，我们确定骨盆带及其周围软骨膜的所有成分都是Tbx4衍生的。此外，尽管Tbx4被认为主要与后肢相关，但在一项研究中，我们表征了两个前肢表达区域，在这项研究中，我们重新详细地检查了Tbx4的表达，并用先前产生的、但未完全表征的Tbx4敲入Cre等位基因追踪了Tbx4表达细胞的命运(Naiche A等人，2001年，Dev dyn出版)。在目前的工作中，我们正在研究BMP信号作为发生在间充质指间细胞中的正常程序性细胞死亡的效应器所起的作用，从而去除它们并在出生时没有鳍状肢体的动物中塑造最终的手指模式。在以前的工作中，为一种新的模型提供了遗传学证据，在这种模型中，表面外胚层必须接收BMP信号，导致FGFs的下调，这反过来又诱导潜在的间充质细胞凋亡(Pajni-Underwood S.等人，2007年开发134：2359)。因此，我们证明BMPs通过调节成纤维细胞生长因子信号间接控制细胞程序性死亡。然而，必须强调的是，这一见解并不排除BMP信号在控制肢体发育中的细胞死亡方面的直接作用。因此，我们通过研究BMP和FGF信号在肢体发育的各个方面的作用来扩展这些研究，使用在发育肢体特定区域表达Cre的小鼠系。例如，检验BMPs作为细胞死亡直接效应因子的假设的唯一方法是，仅在经历细胞死亡的谱系中灭活BMPs受体，而不影响附近细胞中的FGF表达。我们已经使用新的Cre品系实现了这一点，这种品系允许Cre介导的基因在这些谱系中失活。这些问题是：BMP是正常的程序性细胞死亡的直接影响因素吗？如果不是，程序性细胞死亡是如何控制的？如果是这样，BMP是如何实现这一目标的？在另一项研究中，我们发现了FGFs和BMP之间的一个重要信号节点，它对肢体骨骼的正常发育至关重要。我们之前的工作，如上所述，证明了特定的FGFs，从肢芽的远端结构中分泌出来，调节肢体的正常生长和模式。在目前的工作中，我们正在产生遗传学证据，表明BMP向骨骼元素的前体群体发出信号，通过控制成纤维细胞生长因子拮抗剂的表达来调节这种成纤维细胞生长因子信号。这两个信号通路的连接不仅是对肢体如何形成模式的独特洞察，而且可能为这两个通路在其他发育背景下或癌症期间如何相互作用提供一个模型。