School of Life Science and Technology, Tokyo Institute of Technology, 4259-B-25 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan.
Laboratory of Developmental Genetics, Institute of Resource Development and Analysis, Chuo-Ku, Honjo 2-2-1, Kumamoto, 860-0811, Japan.
Sci Rep. 2020 Jul 22;10(1):12187. doi: 10.1038/s41598-020-68987-z.
Insulin gene mutations have been identified to cause monogenic diabetes, and most of which developed permanent neonatal diabetes at young ages before 6 months of age in humans. To establish an animal model of permanent diabetes, we performed genome editing using the CRISPR/Cas9 system. We generated a novel Kuma mutant mice with p.Q104del in the Insulin2 (Ins2) gene in a BRJ background that exhibits a severe immune deficiency. Kuma mutant mice are non-obese and developed hyperglycemia from 3 weeks after birth in both males and females, which are inherited in a dominant mode. Kuma mutant mice displayed reduced insulin protein levels from 3-weeks-old, which seem to be caused by the low stability of the mutant insulin protein. Kuma mutant showed a reduction in islet size and islet mass. Electron microscopic analysis revealed a marked decrease in the number and size of insulin granules in the beta-cells of the mutant mice. Hyperglycemia of the mutant can be rescued by insulin administration. Our results present a novel insulin mutation that causes permanent early-onset diabetes, which provides a model useful for islet transplantation studies.
胰岛素基因突变已被确定可导致单基因糖尿病，其中大多数在人类 6 个月龄之前的幼年时期就发展为永久性新生儿糖尿病。为了建立永久性糖尿病的动物模型，我们使用 CRISPR/Cas9 系统进行了基因组编辑。我们在 BRJ 背景下生成了一种新型的 Kuma 突变小鼠，其胰岛素 2 (Ins2) 基因中的 p.Q104del 导致严重的免疫缺陷。Kuma 突变小鼠非肥胖，雌雄两性均从出生后 3 周开始出现高血糖，呈显性遗传模式。Kuma 突变小鼠从 3 周龄开始表现出胰岛素蛋白水平降低，这似乎是由于突变胰岛素蛋白的稳定性低所致。Kuma 突变小鼠的胰岛大小和胰岛质量减少。电子显微镜分析显示突变小鼠的β细胞中胰岛素颗粒的数量和大小明显减少。通过给予胰岛素，可纠正突变小鼠的高血糖。我们的研究结果提出了一种新的胰岛素突变，可导致永久性早发糖尿病，为胰岛移植研究提供了一种有用的模型。
