Department of Ophthalmology, Shanghai Fifth People's Hospital, Fudan University, Shanghai 200240, China.
Comput Math Methods Med. 2022 Mar 7;2022:9212116. doi: 10.1155/2022/9212116. eCollection 2022.
DNA methylation played a vital role in the progression of diabetic retinopathy. In this study, we aimed to explore the role of DNA cytosine-5-methyltransferase 1 (DNMT1) in the development of early diabetic retinopathy and its potential underlying mechanism.
Eight-week-old healthy Mongolian gerbils were used to establish type 1 diabetes using streptozotocin (STZ). Alteration of weight, fasting blood glucose, density of RGCs (Tuj1-labeled), and H&E-stained retinal cross sections were applied to evaluate the diabetic retinopathy mouse model. The global DNA methylation level of the retina at different time points after STZ injection was measured using the global methylation assay. Western blot was used to detect the protein expression of DNMT1, DNA methyltransferase 3A (DNMT3A), and 3B (DNMT3B). Quantitative reverse transcription-polymerase chain reactions (qRT-PCR) and western blot were used to determine the expression of CDKN2B. Cell proliferation and cell cycle were evaluated by the MTS assay and flow cytometry.
STZ injection caused the increased global DNA methylation level, which reached a maximum at 6 weeks after injection. Moreover, STZ injection caused the damage of RGCs. At 6 weeks after STZ injection, the expression levels of DNMT1 and DNMT3B were significantly increased in the STZ group. DNMT1-induced DNA hypermethylation inhibited the expression of CDKN2B (a negative regulator of cell cycle). DNMT1-mediated DNA methylation facilitated RGC proliferation via regulating the expression of CDKN2B.
DNMT1-mediated DNA methylation played an important role in STZ-induced diabetic retinopathy via modulating CDKN2B expression.
DNA 甲基化在糖尿病视网膜病变的进展中起着至关重要的作用。在本研究中，我们旨在探讨 DNA 胞嘧啶-5-甲基转移酶 1（DNMT1）在早期糖尿病视网膜病变发展中的作用及其潜在的机制。
使用链脲佐菌素（STZ）建立 8 周龄健康蒙古沙土鼠的 1 型糖尿病模型。体重、空腹血糖、Tuj1 标记的 RGC 密度和 H&E 染色的视网膜切片的变化用于评估糖尿病视网膜病变小鼠模型。使用全局甲基化测定法测量 STZ 注射后不同时间点视网膜的全局 DNA 甲基化水平。Western blot 用于检测 DNMT1、DNA 甲基转移酶 3A（DNMT3A）和 3B（DNMT3B）的蛋白表达。定量逆转录-聚合酶链反应（qRT-PCR）和 Western blot 用于测定 CDKN2B 的表达。MTS 测定法和流式细胞术评估细胞增殖和细胞周期。
STZ 注射导致全局 DNA 甲基化水平升高，在注射后 6 周达到最大值。此外，STZ 注射导致 RGC 损伤。在 STZ 注射后 6 周，STZ 组中 DNMT1 和 DNMT3B 的表达水平明显增加。DNMT1 诱导的 DNA 超甲基化抑制了 CDKN2B（细胞周期的负调节剂）的表达。DNMT1 介导的 DNA 甲基化通过调节 CDKN2B 的表达促进 RGC 增殖。
DNMT1 介导的 DNA 甲基化通过调节 CDKN2B 的表达在 STZ 诱导的糖尿病视网膜病变中起重要作用。
