School of Biomedical Sciences, University of Ulster, Coleraine, UK.
Pancreas. 2010 Oct;39(7):1016-23. doi: 10.1097/MPA.0b013e3181dafaa2.
Cellular communication is required for normal patterns of insulin secretion from β cells. Experiments using isolated islets of Langerhans are hampered by lack of supply and the consuming isolation process. Pseudoislets comprising clonal cells have emerged as an alternative to study islet-cell interactions and insulin secretion. The current study compared MIN6 pseudoislets and freshly isolated mouse islets.
Insulin content and release were measured by insulin radioimmunoassay. Reverse transcription polymerase chain reaction and Western blot analysis of adhesion molecule expression were performed on MIN6 monolayers and pseudoislets. MIN6 cellular proliferation and viability were measured by 5-bromo-2-deoxyuridine (BrdU) enzyme-linked immunosorbent assay, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and lactate dehydrogenase assays.
Mouse islets were found to have greater insulin content than pseudoislets. However, insulin release was comparable between the 2 groups. With the use of MIN6 monolayers as a control, the expression of the adhesion molecule E-cadherin and connexin 36 were found to be enhanced in cells cultured as pseudoislets. Moreover, connexin 43 was shown to be absent from MIN6 cells irrespective of configuration. Finally, MIN6 pseudoislets seem able to manage their rate of proliferation with apoptosis resulting in a static size in the culture for extended periods.
The current study found that MIN6 pseudoislets share many important functional and molecular features with islets of Langerhans.
细胞间通讯对于β细胞正常的胰岛素分泌模式是必需的。使用分离的胰岛进行实验受到供应不足和耗费的分离过程的限制。由克隆细胞组成的拟胰岛已成为研究胰岛细胞相互作用和胰岛素分泌的替代方法。本研究比较了 MIN6 拟胰岛和新鲜分离的小鼠胰岛。
通过胰岛素放射免疫测定法测量胰岛素含量和释放。在 MIN6 单层和拟胰岛上进行黏附分子表达的逆转录聚合酶链反应和 Western blot 分析。通过 5-溴-2-脱氧尿苷（BrdU）酶联免疫吸附试验、3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐（MTT）和乳酸脱氢酶测定来测量 MIN6 细胞的增殖和活力。
发现小鼠胰岛的胰岛素含量高于拟胰岛。然而，两组之间的胰岛素释放相当。使用 MIN6 单层作为对照，发现黏附分子 E-钙黏蛋白和连接蛋白 36 的表达在培养为拟胰岛的细胞中增强。此外，无论细胞形态如何，MIN6 细胞中均不存在连接蛋白 43。最后，MIN6 拟胰岛似乎能够通过凋亡来控制其增殖速度，从而在培养物中维持静态大小以延长时间。
本研究发现 MIN6 拟胰岛与胰岛具有许多重要的功能和分子特征。
