Department of Clinical Sciences in Malmö, Units of Molecular Metabolism, Lund University Diabetes Centre, Scania University Hospital, SE-205 02, Malmö, Sweden.
Metabolism. 2012 Jul;61(7):978-85. doi: 10.1016/j.metabol.2011.11.013. Epub 2012 Feb 2.
Nearly all mammalian cells express a set of genes known as clock genes. These regulate the circadian rhythm of cellular processes by means of negative and positive autoregulatory feedback loops of transcription and translation. Recent genomewide association studies have demonstrated an association between a polymorphism near the circadian clock gene CRY2 and elevated fasting glucose. To determine whether clock genes could play a pathogenetic role in the disease, we examined messenger RNA (mRNA) expression of core clock genes in human islets from donors with or without type 2 diabetes mellitus. Microarray and quantitative real-time polymerase chain reaction analyses were used to assess expression of the core clock genes CLOCK, BMAL-1, PER1 to 3, and CRY1 and 2 in human islets. Insulin secretion and insulin content in human islets were measured by radioimmunoassay. The mRNA levels of PER2, PER3, and CRY2 were significantly lower in islets from donors with type 2 diabetes mellitus. To investigate the functional relevance of these clock genes, we correlated their expression to insulin content and glycated hemoglobin levels: mRNA levels of PER2 (ρ = 0.33, P = .012), PER3 (ρ = 0.30, P = .023), and CRY2 (ρ = 0.37, P = .0047) correlated positively with insulin content. Of these genes, expression of PER3 and CRY2 correlated negatively with glycated hemoglobin levels (ρ = -0.44, P = .0012; ρ = -0.28, P = .042). Furthermore, in an in vitro model mimicking pathogenetic conditions, the PER3 mRNA level was reduced in human islets exposed to 16.7 mmol/L glucose per 1 mmol/L palmitate for 48 hours (P = .003). Core clock genes are regulated in human islets. The data suggest that perturbations of circadian clock components may contribute to islet pathophysiology in human type 2 diabetes mellitus.
几乎所有哺乳动物细胞都表达一组称为时钟基因的基因。这些基因通过转录和翻译的负反馈和正反馈自动调节细胞过程的昼夜节律。最近的全基因组关联研究表明，昼夜节律钟基因 CRY2 附近的一个多态性与空腹血糖升高有关。为了确定时钟基因是否在疾病中起致病作用，我们检查了有无 2 型糖尿病的供体胰岛中的核心时钟基因的信使 RNA(mRNA)表达。使用微阵列和定量实时聚合酶链反应分析来评估人类胰岛中核心时钟基因 CLOCK、BMAL-1、PER1 至 3 和 CRY1 和 2 的表达。通过放射免疫测定法测量人类胰岛中的胰岛素分泌和胰岛素含量。来自 2 型糖尿病供体的胰岛中 PER2、PER3 和 CRY2 的 mRNA 水平显着降低。为了研究这些时钟基因的功能相关性，我们将其表达与胰岛素含量和糖化血红蛋白水平相关联：PER2 的 mRNA 水平（ρ=0.33，P=0.012），PER3（ρ=0.30，P=0.023）和 CRY2（ρ=0.37，P=0.0047）与胰岛素含量呈正相关。在这些基因中，PER3 和 CRY2 的表达与糖化血红蛋白水平呈负相关（ρ=-0.44，P=0.0012；ρ=-0.28，P=0.042）。此外，在模拟致病条件的体外模型中，PER3 mRNA 水平在暴露于 16.7 mmol/L 葡萄糖/1 mmol/L 棕榈酸的人胰岛中降低 48 小时（P=0.003）。核心时钟基因在人类胰岛中受到调节。数据表明，昼夜节律钟成分的干扰可能导致人类 2 型糖尿病的胰岛病理生理学。
