Epigenomic landscapes of human primary pancreatic cell types. Homo sapiens

Intensive efforts are focused on identifying regulators of human pancreatic islet cell growth and maturation to accelerate development of therapies for diabetes. After birth, islet cell growth and function are dynamically regulated; however, establishing these age-dependent changes in humans has been challenging. Here we describe a multimodal strategy for isolating pancreatic endocrine and exocrine cells from children and adults to identify age-dependent gene expression and chromatin changes on a genomic scale. These profiles revealed distinct proliferative and functional states of islet alpha-cells or beta-cells, and histone modifications underlying age-dependent gene expression changes. Expression of SIX2 and SIX3, transcription factors without prior known functions in the pancreas and linked to fasting hyperglycemia risk, increased with age specifically in human islet beta-cells. SIX2 and SIX3 were sufficient to enhance insulin content or secretion in immature beta-cells. Our work provides a unique resource to study human-specific regulators of islet cell maturation and function. Overall design: For this study we purified primary human pancreatic cells from juvenile and adult donors and analyzed the chromatin landscape using ChIP-Seq assays.

本研究聚焦于鉴定人类胰岛细胞生长与成熟的调控因子，以期加速糖尿病治疗手段的研发进程。出生后，胰岛细胞的生长与功能处于动态调控之中，但在人类样本中明确此类年龄依赖性的变化始终颇具挑战。本研究开发了一种多模态策略，可从儿童与成人胰腺中分离内分泌与外分泌细胞，从而在全基因组范围内鉴定年龄依赖性的基因表达与染色质变化。上述分析图谱揭示了胰岛α细胞与β细胞独特的增殖及功能状态，以及介导年龄依赖性基因表达变化的组蛋白修饰机制。转录因子SIX2与SIX3此前未被报道在胰腺中发挥功能，且与空腹高血糖风险相关，其表达仅在人类胰岛β细胞中随年龄增长而上调。实验证实，SIX2与SIX3即可提升未成熟β细胞的胰岛素含量与分泌能力。本研究为探究胰岛细胞成熟与功能的人类特异性调控因子提供了独特的研究资源。实验设计方案：本研究从青少年与成人供体中分离原代人胰腺细胞，并通过染色质免疫共沉淀测序（ChIP-Seq）分析其染色质景观。