Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon, South Korea.
Diabetes Metab Res Rev. 2011 Nov;27(8):813-9. doi: 10.1002/dmrr.1233.
Type 2 diabetes is characterized by progressive beta-cell failure and apoptosis is probably the main form of beta-cell death in this disease. It was reported that circulating levels of interleukin-6 are elevated in type 2 diabetic patients, but whether this is involved in the pathogenesis of type 2 diabetes is still debated. In this study, we examined whether interleukin-6 can induce beta-cell damage in vitro and elucidated its mechanisms.
To examine the effect of interleukin-6 on beta cells, glucose-stimulated insulin secretion (GSIS) by enzyme immunoassay (EIA) method and cell apoptosis by propidium iodide and annexin-V staining were measured in a rat beta-cell line (INS-1 or INS-832/13) after treatment with interleukin-6. The expression of apoptosis-related molecules was measured using western blotting and nitric oxide (NO) production was measured using Griess assay. AG490 and N-monomethyl-L-arginine were used to inhibit Janus kinase-mediated signal transducers and activators of transcription signalling and NO production, respectively.
Exposure (48 h) of INS-1 cells to 20 ng/mL interleukin-6 significantly decreased GSIS as well as cell viability. We found that sub-G1/G0 population was increased as compared with untreated cells and expression of cleaved caspase-3, cleaved poly(ADP-ribose) polymerase, phosphorylated p38 mitogen-activated protein kinase and phosphorylated nuclear factor-κB was increased in interleukin-6-treated INS-1 cells. Interleukin-6 increased the amount of early apoptotic cells; this increase was blocked by AG490 or N-monomethyl-L-arginine treatment. Moreover, NO production, which is known to induce apoptosis, was increased by interleukin-6 treatment but abrogated in AG490-treated cells.
Our results show that exposure to interleukin-6 for 48 h can induce beta-cell death, in part via signal transducers and activators of transcription-3-mediated NO production.
2 型糖尿病的特征是β细胞进行性衰竭，细胞凋亡可能是这种疾病中β细胞死亡的主要形式。有报道称，2 型糖尿病患者的循环白细胞介素 6 水平升高，但这是否与 2 型糖尿病的发病机制有关仍存在争议。在这项研究中，我们研究了白细胞介素 6 是否可以在体外诱导β细胞损伤，并阐明其机制。
为了研究白细胞介素 6 对β细胞的影响，用酶联免疫吸附测定（EIA）法检测大鼠β细胞系（INS-1 或 INS-832/13）经白细胞介素 6 处理后葡萄糖刺激的胰岛素分泌（GSIS），用碘化丙啶和膜联蛋白-V 染色检测细胞凋亡。用 Western blot 检测凋亡相关分子的表达，用 Griess 法检测一氧化氮（NO）的产生。用 AG490 和 N-单甲基-L-精氨酸分别抑制 Janus 激酶介导的信号转导和转录激活因子信号和 NO 的产生。
暴露（48 h）于 20ng/ml 白细胞介素 6 显著降低了 INS-1 细胞的 GSIS 和细胞活力。我们发现，与未经处理的细胞相比，亚 G1/G0 期细胞增多，白细胞介素 6 处理的 INS-1 细胞中 cleaved caspase-3、cleaved poly（ADP-ribose）polymerase、磷酸化 p38 丝裂原活化蛋白激酶和磷酸化核因子-κB 的表达增加。白细胞介素 6 增加了早期凋亡细胞的数量；这种增加被 AG490 或 N-单甲基-L-精氨酸处理所阻断。此外，白细胞介素 6 处理可增加已知诱导凋亡的一氧化氮（NO）的产生，但在 AG490 处理的细胞中则被阻断。
我们的结果表明，暴露于白细胞介素 6 48 h 可诱导β细胞死亡，部分通过信号转导和转录激活因子 3 介导的一氧化氮（NO）产生。
