Saarimäki-Vire Jonna, Balboa Diego, Russell Mark A, Saarikettu Juha, Kinnunen Matias, Keskitalo Salla, Malhi Amrinder, Valensisi Cristina, Andrus Colin, Eurola Solja, Grym Heli, Ustinov Jarkko, Wartiovaara Kirmo, Hawkins R David, Silvennoinen Olli, Varjosalo Markku, Morgan Noel G, Otonkoski Timo
Research Programs Unit, Molecular Neurology and Biomedicum Stem Cell Centre, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland.
Research Programs Unit, Molecular Neurology and Biomedicum Stem Cell Centre, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland.
Cell Rep. 2017 Apr 11;19(2):281-294. doi: 10.1016/j.celrep.2017.03.055.
Activating germline mutations in STAT3 were recently identified as a cause of neonatal diabetes mellitus associated with beta-cell autoimmunity. We have investigated the effect of an activating mutation, STAT3, on pancreatic development using induced pluripotent stem cells (iPSCs) derived from a patient with neonatal diabetes and pancreatic hypoplasia. Early pancreatic endoderm differentiated similarly from STAT3 and healthy-control cells, but in later stages, NEUROG3 expression was upregulated prematurely in STAT3 cells together with insulin (INS) and glucagon (GCG). RNA sequencing (RNA-seq) showed robust NEUROG3 downstream targets upregulation. STAT3 mutation correction with CRISPR/Cas9 reversed completely the disease phenotype. STAT3-activating properties were not explained fully by altered DNA-binding affinity or increased phosphorylation. Instead, reporter assays demonstrated NEUROG3 promoter activation by STAT3 in pancreatic cells. Furthermore, proteomic and immunocytochemical analyses revealed increased nuclear translocation of STAT3. Collectively, our results demonstrate that the STAT3 mutation causes premature endocrine differentiation through direct induction of NEUROG3 expression.
信号转导与转录激活因子3（STAT3）的种系激活突变最近被确定为与β细胞自身免疫相关的新生儿糖尿病的病因。我们利用来自一名患有新生儿糖尿病和胰腺发育不全患者的诱导多能干细胞（iPSC），研究了激活突变STAT3对胰腺发育的影响。早期胰腺内胚层与STAT3细胞和健康对照细胞的分化相似，但在后期，STAT3细胞中神经源性分化因子3（NEUROG3）的表达与胰岛素（INS）和胰高血糖素（GCG）一起过早上调。RNA测序（RNA-seq）显示NEUROG3下游靶点强烈上调。用CRISPR/Cas9校正STAT3突变完全逆转了疾病表型。STAT3的激活特性不能完全由改变的DNA结合亲和力或增加的磷酸化来解释。相反，报告基因分析表明STAT3在胰腺细胞中激活NEUROG3启动子。此外，蛋白质组学和免疫细胞化学分析显示STAT3的核转位增加。总之，我们的结果表明，STAT3突变通过直接诱导NEUROG3表达导致过早的内分泌分化。
