Impaired periodontal healing is a common complication of diabetes mellitus (DM), frequently related to hyperglycemia. MicroRNAs 221 and 222 have been studied as biomarkers for inflammatory diseases, including diabetes, but their role in the periodontal ligament (PL) is unknown. The effects of high glucose on human PL cells death were studied, as well as the expression of microRNA-221 and microRNA-222, potentially modulated by DM. Cells were obtained from the premolar teeth of young humans and cultured for 7 days under different glucose concentrations (5 or 30 mM). MicroRNAs-221/222 expressions were evaluated by real-time RT-PCR and apoptosis by TUNEL assays. Caspase-3 expression was studied by western blotting and immunocytochemistry. High glucose increased apoptosis and caspase-3 protein expression by about 3×. MicroRNA-221 and microRNA-222 expressions decreased by nearly 40% under high glucose. MicroRNA-221 and microRNA-222 inhibition using antagomiRs increased apoptosis by 2–3×, while the expression of caspase-3, a validated target for these microRNAs, was increased by 50%. The overexpression of both microRNAs using miR mimics in high glucose cells did no effect on apoptosis but increased caspase-3 expression by 30%. In conclusion, high glucose induces apoptosis of human PL cells potentially through a reduction of microRNA-221 and microRNA-222 expression and elevation of caspase-3.

中文翻译：

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MicroRNAs 221 和 222 表达降低介导高糖诱导人牙周膜细胞凋亡。

牙周愈合受损是糖尿病 (DM) 的常见并发症，通常与高血糖有关。MicroRNA 221 和 222 已被研究作为炎症性疾病（包括糖尿病）的生物标志物，但它们在牙周膜 (PL) 中的作用尚不清楚。研究了高葡萄糖对人类 PL 细胞死亡的影响，以及可能受 DM 调节的 microRNA-221 和 microRNA-222 的表达。细胞取自年轻人的前磨牙，并在不同葡萄糖浓度（5 或 30 mM）下培养 7 天。通过实时 RT-PCR 评估 MicroRNAs-221/222 表达，通过 TUNEL 测定评估细胞凋亡。通过蛋白质印迹和免疫细胞化学研究 Caspase-3 表达。高糖使细胞凋亡和 caspase-3 蛋白表达增加约 3 倍。MicroRNA-221和microRNA-222的表达在高糖条件下下降了近40%。使用 antagomiRs 抑制 MicroRNA-221 和 microRNA-222 可使细胞凋亡增加 2-3 倍，而这些 microRNA 的有效靶标 caspase-3 的表达增加了 50%。在高糖细胞中使用 miR 模拟物过表达两种 microRNA 对细胞凋亡没有影响，但使 caspase-3 表达增加了 30%。总之，高葡萄糖可能通过减少 microRNA-221 和 microRNA-222 的表达以及 caspase-3 的升高来诱导人 PL 细胞凋亡。在高糖细胞中使用 miR 模拟物过表达两种 microRNA 对细胞凋亡没有影响，但使 caspase-3 表达增加了 30%。总之，高葡萄糖可能通过减少 microRNA-221 和 microRNA-222 的表达以及 caspase-3 的升高来诱导人 PL 细胞凋亡。在高糖细胞中使用 miR 模拟物过表达两种 microRNA 对细胞凋亡没有影响，但使 caspase-3 表达增加了 30%。总之，高葡萄糖可能通过减少 microRNA-221 和 microRNA-222 的表达以及 caspase-3 的升高来诱导人 PL 细胞凋亡。