Heterozygous missense variant in GLI2 impairs human endocrine pancreas development. Heterozygous missense variant in GLI2 impairs human endocrine pancreas development

To study the impact of an heterozygous missense variant in GLI2 in pancreatic cell differentiation and function, we established a patient-like pluripotent stem cell model. Interestingly, engineered iPSC lines carrying the identified missense variant in the gene GLI2 showed impaired differentiation into endocrine progenitors. To further characterize putative downstream mechanisms underlying the impaired endocrine differentiation of iPSCs, we performed bulk RNA-seq at three stages of differentiation (iPSC, gut tube and endocrine progenitor stages). At early stages (iPSC and gut tube stage), the transcriptome of GLI2-CTRL and GLI2-MUT-derived cells was highly comparable, with only 48 genes significantly dysregulated at gut tube stage. By contrast, differences at the transcriptome level became evident at endocrine progenitor stage [928 genes upregulated and 1070 downregulated in mutant versus control cells]. Overall design: Comparative gene expression profiling analysis of RNA-seq data for human iPSC cells [control and mutant (MUT) lines] at two stages of pancreatic differentiation (PD)

为探究GLI2基因杂合错义变异对胰腺细胞分化与功能的影响，我们构建了类患者诱导多能干细胞（induced pluripotent stem cell, iPSC）模型。值得注意的是，携带有经鉴定的GLI2基因错义变异的工程化iPSC株系，其向内分泌祖细胞的分化过程受到损伤。为进一步解析iPSC内分泌分化受损背后的潜在下游调控机制，我们在分化的三个阶段（iPSC阶段、肠管阶段及内分泌祖细胞阶段）开展了批量RNA测序（bulk RNA-seq）。在早期阶段（iPSC与肠管阶段），GLI2-CTRL与GLI2-MUT来源细胞的转录组高度相似，仅在肠管阶段有48个基因出现显著表达失调。与之相比，在内分泌祖细胞阶段，转录组水平的差异更为显著：相较于对照细胞，突变型细胞中共有928个基因上调、1070个基因下调。整体实验设计：针对处于胰腺分化（pancreatic differentiation, PD）两个阶段的人iPSC细胞（对照株系与突变株系）的RNA-seq数据，开展比较基因表达谱分析。