Insulin gene mutations resulting in early-onset diabetes: marked differences in clinical presentation, metabolic status, and pathogenic effect through endoplasmic reticulum retention.
Insulin gene mutations resulting in early-onset diabetes: marked differences in clinical presentation, metabolic status, and pathogenic effect through endoplasmic reticulum retention.
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DOI：
10.2337/db09-1091
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发表时间：
2010-03
期刊：
影响因子：
7.7
通讯作者：
Vaxillaire M
中科院分区：
文献类型：
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作者：
Meur G;Simon A;Harun N;Virally M;Dechaume A;Bonnefond A;Fetita S;Tarasov AI;Guillausseau PJ;Boesgaard TW;Pedersen O;Hansen T;Polak M;Gautier JF;Froguel P;Rutter GA;Vaxillaire M
人前胰岛素原（INS）基因的杂合突变是非综合征性新生儿或婴儿早期糖尿病的原因。在这里，我们试图确定与青年期成熟型糖尿病（MODY）或中年期非自身免疫性糖尿病相关的INS突变，并探讨相关的分子机制。对16名不明原因MODY的法国先证者、95名非自身免疫性早发性糖尿病患者（确诊年龄<35岁）和292名血糖正常的法国籍对照者进行INS基因测序。通过对编码前胰岛素原-绿色荧光蛋白（GFP）（C肽）嵌合体的cDNA进行定点诱变，产生了三种经鉴定的胰岛素突变体。通过免疫细胞化学和胰岛素原分泌，通过放射免疫测定法在克隆β细胞中评估细胞内靶向。通过实时PCR定量剪接的XBP1和C/EBP同源蛋白。一个新的编码突变，L30 M，可能影响胰岛素多聚化，被确定在5个糖尿病患者（糖尿病发病17 - 36岁）在一个家庭。L30M前胰岛素原-GFP荧光主要与MIN6 β细胞中的内质网（ER）相关，并且ER退出被抑制50%。另外两个突变体，R55 C（在B/C连接处）和R6 H（在信号肽中），通常靶向分泌颗粒，但仍然引起大量的ER应激。我们描述了三种INS突变与早发性糖尿病共分离，其临床表现与MODY一致。这些导致产生具有显著不同的运输特性和对ER应激的影响的（前）胰岛素原分子，表明β细胞中存在一系列分子缺陷。
Heterozygous mutations in the human preproinsulin (INS) gene are a cause of nonsyndromic neonatal or early-infancy diabetes. Here, we sought to identify INS mutations associated with maturity-onset diabetes of the young (MODY) or nonautoimmune diabetes in mid-adult life, and to explore the molecular mechanisms involved. The INS gene was sequenced in 16 French probands with unexplained MODY, 95 patients with nonautoimmune early-onset diabetes (diagnosed at <35 years) and 292 normoglycemic control subjects of French origin. Three identified insulin mutants were generated by site-directed mutagenesis of cDNA encoding a preproinsulin–green fluorescent protein (GFP) (C-peptide) chimera. Intracellular targeting was assessed in clonal β-cells by immunocytochemistry and proinsulin secretion, by radioimmunoassay. Spliced XBP1 and C/EBP homologous protein were quantitated by real-time PCR. A novel coding mutation, L30M, potentially affecting insulin multimerization, was identified in five diabetic individuals (diabetes onset 17–36 years) in a single family. L30M preproinsulin-GFP fluorescence largely associated with the endoplasmic reticulum (ER) in MIN6 β-cells, and ER exit was inhibited by ∼50%. Two additional mutants, R55C (at the B/C junction) and R6H (in the signal peptide), were normally targeted to secretory granules, but nonetheless caused substantial ER stress. We describe three INS mutations cosegregating with early-onset diabetes whose clinical presentation is compatible with MODY. These led to the production of (pre)proinsulin molecules with markedly different trafficking properties and effects on ER stress, demonstrating a range of molecular defects in the β-cell.