SAAD Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, UK.
Diabetes Metab Res Rev. 2010 Oct;26(7):525-33. doi: 10.1002/dmrr.1111.
Pseudoislet studies have concentrated on single beta-cell lines or a combination of insulin and glucagon-secreting cells, overlooking the potential role of somatostatin in insulin release. This study sought to evaluate a heterotypic pseudoislet model containing insulin- (MIN6), glucagon- (αTC1.9) and somatostatin (TGP52)-secreting cells of mouse origin and to compare these pseudoislets with traditional monolayer preparations.
Cellular viability (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and lactate dehydrogenase assays), proliferation (5-bromo-2-deoxyuridine ELISA), hormone content and functional insulin release in response to a variety of stimuli were measured. Differential expression of E-cadherin, connexin 36 and connexin 43 was assessed by reverse transcriptase-polymerase chain reaction and Western blot to determine a possible role for adherens in insulin release from these pseudoislets.
All pseudoislet cells displayed reduced proliferation coupled with an increase in cell death which may contribute to their static size in culture. While MIN6 and TGP52 cells expressed E-cadherin and showed sustained or improved hormone content when configured as pseudoislets, αTC1.9 lacked E-cadherin and contained less glucagon following pseudoislet formation. MIN6 and αTC1.9 cells expressed connexin 36, but not connexin 43 and TGP52 cells expressed connexin 43 only. In the presence of Alanine, Arginine and glucagon-like peptide-1, heterotypic pseudoislet cultures secreted levels of insulin that were comparable to that of MIN6 pseudoislets. In addition, pseudoislets comprising all three cell lines released more insulin into the surrounding culture medium than MIN6 pseudoislets when studied over a 1-week period.
The current model may prove useful in studying the role of islet cell interactions in the release of insulin from pancreatic islets.
胰岛研究集中在单一的β细胞系或胰岛素和胰高血糖素分泌细胞的组合上，忽略了生长抑素在胰岛素释放中的潜在作用。本研究旨在评估一种包含胰岛细胞（MIN6）、胰高血糖素细胞（αTC1.9）和生长抑素细胞（TGP52）的异质拟胰岛模型，并将这些拟胰岛与传统的单层细胞培养物进行比较。
通过 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐和乳酸脱氢酶测定法评估细胞活力、5-溴-2-脱氧尿苷 ELISA 评估增殖、激素含量和对各种刺激的功能性胰岛素释放。通过逆转录-聚合酶链反应和 Western blot 评估 E-钙粘蛋白、连接蛋白 36 和连接蛋白 43 的差异表达，以确定连接黏附在这些拟胰岛中胰岛素释放中的可能作用。
所有拟胰岛细胞的增殖减少伴随着细胞死亡的增加，这可能导致它们在培养中的静态大小。虽然 MIN6 和 TGP52 细胞表达 E-钙粘蛋白，并且在构成拟胰岛时显示出持续或改善的激素含量，但 αTC1.9 缺乏 E-钙粘蛋白并且在形成拟胰岛后含有较少的胰高血糖素。MIN6 和 αTC1.9 细胞表达连接蛋白 36，但不表达连接蛋白 43，而 TGP52 细胞仅表达连接蛋白 43。在丙氨酸、精氨酸和胰高血糖素样肽-1 的存在下，异质拟胰岛培养物分泌的胰岛素水平与 MIN6 拟胰岛相当。此外，当在 1 周的时间内进行研究时，包含所有三种细胞系的拟胰岛释放到周围培养基中的胰岛素比 MIN6 拟胰岛更多。
该模型可能有助于研究胰岛细胞相互作用在胰岛胰岛素释放中的作用。
