A chemical-genetic approach to study G protein regulation of β cell function in vivo
A chemical-genetic approach to study G protein regulation of β cell function in vivo
复制标题
DOI：
10.1073/pnas.0906593106
复制
发表时间：
2009-11-10
影响因子：
11.1
通讯作者：
Wess, Juergen
中科院分区：
文献类型：
--
作者：
Guettier, Jean-Marc;Gautam, Dinesh;Wess, Juergen
胰岛β细胞功能受损是2型糖尿病的一个重要标志。β细胞功能受不同类型的异源三聚体G蛋白的作用调节。激活体内特定的β细胞G蛋白信号通路的功能后果目前还不清楚，这主要是因为许多其他组织也表达β细胞G蛋白偶联受体(GPCRs)。为了绕过这些困难，我们开发了一种化学遗传方法，允许在完整的动物中有条件地和选择性地激活特定的β细胞G蛋白。具体地说，我们创造了两个转基因小鼠品系，每个品系只在β细胞中表达特定的设计GPCR。重要的是，这两种设计受体的G蛋白偶联特性不同(G(Q/11)和G(S))。它们不能结合内源性配体(S)，但可以被其他药理惰性化合物(氯氮平-N-氧化物)有效地激活，导致β细胞G(Q/11)或G(S)G蛋白的有条件激活。在此，我们报道了在体内有条件和选择性地激活β细胞G(Q/11)信号导致第一和第二相胰岛素释放显著增加，显著改善肥胖、胰岛素抵抗小鼠的葡萄糖耐量，以及与胰岛基因表达水平的途径特异性变化相关的β细胞质量增加的结果。选择性刺激β细胞G(S)在体内引发了性质相似的代谢效应。因此，这种发展的化学遗传策略为研究G蛋白对体内β细胞功能的调控提供了一种强有力的方法。
Impaired functioning of pancreatic beta cells is a key hallmark of type 2 diabetes. beta cell function is modulated by the actions of different classes of heterotrimeric G proteins. The functional consequences of activating specific beta cell G protein signaling pathways in vivo are not well understood at present, primarily due to the fact that beta cell G protein-coupled receptors (GPCRs) are also expressed by many other tissues. To circumvent these difficulties, we developed a chemical-genetic approach that allows for the conditional and selective activation of specific beta cell G proteins in intact animals. Specifically, we created two lines of transgenic mice each of which expressed a specific designer GPCR in beta cells only. Importantly, the two designer receptors differed in their G protein-coupling properties (G(q/11) versus G(s)). They were unable to bind endogenous ligand(s), but could be efficiently activated by an otherwise pharmacologically inert compound (clozapine-N-oxide), leading to the conditional activation of either beta cell G(q/11) or G(s) G proteins. Here we report the findings that conditional and selective activation of beta cell G(q/11) signaling in vivo leads to striking increases in both first-and second-phase insulin release, greatly improved glucose tolerance in obese, insulin-resistant mice, and elevated beta cell mass, associated with pathway-specific alterations in islet gene expression levels. Selective stimulation of beta cell G(s) triggered qualitatively similar in vivo metabolic effects. Thus, this developed chemical-genetic strategy represents a powerful approach to study G protein regulation of beta cell function in vivo.