Integrin-linked kinase in pancreas development

我们的实验室以前已经证明，整合素家族的细胞基质粘附受体是 胰岛祖细胞粘附、迁移和分化的重要调节剂。最近，我们有 发现在发育中的胰腺β细胞中β1整联蛋白的消融导致胰腺β细胞中β1整合素的显著减少。 通过负调节促进细胞周期进程的基因的表达来增加β细胞的数量。建筑 基于这些最新发现，我们的目标是研究β1整合素下游效应子的作用 这可能是正常β细胞群发育所需的信号传导。在β1蛋白募集的信号分子中， 整合素在与其ECM配体结合后，ILK（整合素连接的激酶）由于其 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-细胞发育和功能中的可能作用，我们的实验性研究显示， 战略将侧重于以下研究。在第一系列实验（目标1）中，我们将培育Ins 1Cre小鼠 以产生InslCre/ILK-/-动物，并因此在培养期间实现β细胞中ILK的组成性缺失。 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 在第二组实验（目标2）中，我们将在第一组实验期间有条件地删除β细胞中的floxed ILK等位基因。 通过将他莫昔芬诱导型Ins 1CreERT 2基因敲入小鼠与ILKflox/flox小鼠杂交， 生成Ins 1CreERT 2/ILK-/-动物。这些研究的重要性在于能够有条件地消融 ILK在出生后生命的选择时间窗期间，当已知β细胞的最显著扩增时， 发生.最后，（目的3）获得关于ILK可能参与适应性β细胞过程的知识， 为了检测内稳态和再生，我们将测试Ins 1Cre/ILK-/-或Ins 1CreERT 2/ILK-/-动物 补偿暴露于代谢应激源（如高脂肪饮食）后的代谢需求， 链脲佐菌素损伤β细胞后再生。 基于ILK在其他细胞类型中的已知信号传导特性，我们预期所提出的研究 将揭示胰岛细胞新生、生长和分化的新机制， 有助于鉴定促进β细胞发育、扩增、存活的新型可药用靶点 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.