Integrin-linked kinase in pancreas development

我们的实验室先前已经证明，整合素家族的细胞-基质黏附受体是 胰岛祖细胞黏附、迁移和分化的重要调节因子。最近，我们已经 发现在发育中的胰腺β-细胞中消融β-1整合素导致显著减少 通过负调控促进细胞周期进程的基因的表达来增加β-细胞的数量。建房 根据这些最新的发现，在这个方案中，我们的目标是研究β1整合素下游效应因子的作用 正常的β细胞的大量发育可能需要的信号。在β1招募的信号分子中 整合素一旦与其ECM配体结合，ILK(整合素连接激酶)因其 参与多种发育过程，包括细胞迁移、增殖、分化和 细胞存活。因此，为了研究ILK在β细胞发育中的可能作用和我们的实验 战略将集中在以下几个方面的研究。在第一系列实验中(目标1)，我们将培育Ins1Cre小鼠 给ILKFLOX/FLOX小鼠产生Ins1Cre/ILK-/-动物，从而实现β-细胞中ILK的结构性缺失 胚胎生命。这些实验将确定ILK在β-细胞发育和功能中的需求。在……里面 第二组实验(目标2)，我们将在第一组实验中有条件地删除β-细胞中的FLOXED ILK等位基因 将他莫昔芬诱导的Ins1CreERT2基因敲入小鼠与ILKflx/Flox小鼠杂交，获得出生后两周的生命 生成Ins1CreERT2/ilk-/-动物。这些研究的重要性在于有条件消融的能力 在出生后生命的选定时间窗口中，当已知β细胞最显著的扩张时，ILK 发生。最后，(目标3)获得关于ILK可能参与适应性β细胞过程的知识 ，我们将测试Ins1Cre/ilk-/-或Ins1CreERT2/ilk-/-动物的能力 补偿暴露于高脂肪饮食等代谢应激源后的代谢需求，并 链脲佐菌素损伤β细胞后再生。 根据已知的ILK在其他细胞类型中的信号特性，我们预计拟议的研究 将揭示胰岛细胞新生、生长和分化的新机制，并最终可能 有助于识别促进β细胞发育、扩增、存活的新的可用药靶点 和/或再生。

Our laboratory has previously demonstrated that cell-matrix adhesion receptors of the Integrin family are important regulators of islet progenitor cell adhesion, migration and differentiation. More recently, we have discovered that ablation of β1 integrin in developing pancreatic β-cells causes a dramatic reduction of the number of β-cells by negatively regulating the expression of genes promoting cell cycle progression. Building on these recent discoveries, in this proposal our goal is to study the role of downstream effectors of β1 integrin signaling that may be required for proper β-cell mass development. Among signaling molecules recruited by β1 integrins upon binding to their ECM ligands, ILK (integrin-linked kinase) is of significant interest due to its involvement in multiple developmental processes encompassing cell migration, proliferation, differentiation and cell survival. Hence, to investigate the possible role of ILK in β-cell development and function our experimental strategy will focus on the following studies. In a first series of experiments (Aim 1), we will breed Ins1Cre mice to ILKflox/flox mice to generate Ins1Cre/ILK-/- animals and thus achieve constitutive deletion of ILK in β-cells during embryonic life. These experiments will determine the requirement of ILK in β-cell development and function. In a second set of experiments (Aim 2), we will conditionally delete the floxed ILK allele in β-cells during the first two weeks of postnatal life by crossing tamoxifen-inducible Ins1CreERT2 knock-in mice with ILKflox/flox mice to generate Ins1CreERT2/ILK-/- animals. The importance of these studies resides in the ability to conditionally ablate ILK during a select time window of postnatal life when the most significant expansion of β-cells is known to occur. Finally, (Aim 3) to gain knowledge on the possible involvement of ILK in processes of adaptive β-cell homeostasis and regeneration, we will test the ability of either Ins1Cre/ILK-/- or Ins1CreERT2/ILK-/- animals to compensate metabolic demands following the exposure to metabolic stressors such as high fat diet, and to regenerate following β-cell injury by streptozotocin. Based on the known signaling properties of ILK in other cell types, we anticipate that the proposed studies will uncover novel mechanisms of islet cell neogenesis, growth and differentiation, and may ultimately contribute to the identification of novel druggable targets that promote β-cell development, expansion, survival and/or regeneration.