A Novel c.125T>G (p.Val42Gly) Mutation in The Human INS Gene Leads to Neonatal Diabetes Mellitus via a Decrease in Insulin Synthesis

作者：Sun, Fei; Du, Wenhua; Ma, Junhua; Gu, Mingjun; Wang, Jingnan; Zhu, Hongling; Song, Huaidong; Gao, Guanqi^*

来源：Experimental and Clinical Endocrinology & Diabetes, 2020, 128(3): 182-189.

DOI：10.1055/a-0603-3463

• insulin mutation
• neonatal diabetes mellitus
• insulin synthesis

Background Neonatal diabetes mellitus is likely caused by monogenic mutations, several of which have been identified. INS mutations have a broad spectrum of clinical presentations, ranging from severe neonatal onset to mild adult onset, which suggests that the products of different mutant INS alleles behave differently and utilize distinct mechanisms to induce diabetes. In this study, a neonatal diabetes mellitus patient's INS gene was sequenced, and functional experiments were conducted. @@@ Methods The neonatal diabetes mellitus patient's genomic DNA was extracted, and the patient's KCNJ11, ABCC8, and INS genes were sequenced. A novel mutation was identified in INS, and the open reading frame of this human mutant INS gene was inserted into the pMSCV-PIG plasmid. The constructed pMSCV-PIG plasmid was combined with VSV-g and Gag-pol and transfected into 293T cells to package the lentivirus. To stably overexpress the mutant gene, INS-1 cells were infected with the virus. The levels of insulin in the cell culture medium and cytoplasm were determined by ELISA and immunocytochemistry, respectively. @@@ Results A heterozygous mutation, c.125T > G (p. Val42Gly), was identified in a neonatal diabetes mellitus patient's INS gene. The human mutant INS open reading frame was overexpressed in INS-1 cells, and the mutant insulin was undetectable in the cell culture medium and cytoplasm. @@@ Conclusions The novel heterozygous activating mutation c.125 T > G (p.Val42Gly) impairs the synthesis of insulin by pancreatic beta cells, resulting in diabetes.

• 出版日期2020-3
• 单位中国人民解放军第二军医大学; 上海市浦东新区公利医院; 临沂市人民医院; 上海交通大学