目的：探讨N6-甲基腺嘌呤(N6-methyladenosine， m⁶A)甲基化转移酶3(METTL3)在糖尿病性白内障发病中的作用机制。

方法：用低糖和高糖培养基培养人晶状体上皮细胞系(SRA01/04)24h后，采用RT-qPCR和Western blot实验检测细胞的上皮-间质转分化(EMT)指标：E-钙黏蛋白(E-Cadherin)、N-钙黏蛋白(N-Cadherin)、紧密连接蛋白1(ZO-1)和α-平滑肌肌动蛋白(α-SMA)的变化情况； transwell和划痕实验检测细胞迁移能力。采用免疫荧光染色检测人晶状体前囊膜组织中METTL3的表达量及定位，m⁶A dot blot实验检测在低糖和高糖培养基中培养24h细胞的m⁶A甲基化水平， RT-qPCR和Western blot实验检测细胞中METTL3的RNA和蛋白表达量。加入METTL3抑制剂的培养基中培养24h的细胞，RT-qPCR和Western blot实验检测EMT指标的变化情况； m⁶A dot blot实验检测细胞m⁶A甲基化水平； Transwell和划痕实验检测细胞迁移能力。免疫荧光染色检测细胞中转化生成因子β(TGFβ₁)的表达； RT-qPCR和Western blot实验检测细胞中的TGFβ₁和SNAIL的表达量。

结果：与低糖条件相比，高糖条件能够促进细胞EMT的发生，促进METTL3的表达和上调了细胞总RNA的m⁶A甲基化水平(P<0.05)。高糖能够促进细胞的迁移能力。糖尿病性白内障患者晶状体前囊膜中METTL3表达较单纯年龄相关性白内障患者增高。与高糖+DMSO组相比，加入METTL3抑制剂STM2457，能够抑制细胞的EMT发生，抑制TGFβ₁和SNAIL的 表达，抑制细胞总RNA 的m⁶A甲基化水平(均P<0.05)。加入METTL3抑制剂STM2457后细胞迁移能力较高糖+DMSO组降低。

结论：m⁶A甲基化转移酶METTL3通过激活TGFβ₁/SNAIL通路促进了在高糖条件下人晶状体上皮细胞的EMT发生从而诱导糖尿病性白内障的发生。

METHODS: We cultured SRA01/04 cells in low and high sugar media for 24h and measured changes in epithelial-mesenchymal transition(EMT)indicators(E-Cadherin, N-Cadherin, ZO-1 and α-SMA)using RT-qPCR and Western blot assays. Cell migration was also assessed using transwell and scratch assays. To investigate the expression level and localization of METTL3 in human lens anterior capsules tissues. Additionally, we used m⁶A dot blot assay to detect the m⁶A methylation level of cells cultured in low and high glucose media for 24h, and employed RT-qPCR and Western blot experiments to detect RNA and protein expression of METTL3 in cells. We then treated the cells with METTL3 inhibitor and measured changes in EMT markers by RT-qPCR and Western blot; m⁶A methylation level was detected by m⁶A dot blot test; cell migration was detected by Transwell. Finally, the expression of transforming growth factor-β(TGFβ₁)in cultured cells was assessed by immunofluorescence staining and the expression levels of TGFβ₁ and SNAIL in cells were determined using RT-qPCR and Western blot.

RESULTS: Under high glucose conditions, the expression of EMT markers, METTL3, and m⁶A methylation levels were significantly increased in cells(P<0.05). Furthermore, the migratory ability of cells was higher in high-sugar medium than in low-sugar medium. In human lens anterior capsules, METTL3 expression was higher in patients with diabetic cataract compared to those with age-related cataract. Importantly, treatment with the METTL3 inhibitor STM2457 inhibited EMT in cells, the expression of TGFβ1 and SNAIL, as well as m⁶A methylation levels in cells(all P<0.05)compared to high-sugar + dimethyl sulfoxide(DMSO)group. Moreover, the migratory capacity of cells was reduced after the addition of STM2457 compared to the high-sugar + DMSO group.

CONCLUSION:METTL3 promotes the EMT in human lens epithelial cells under high glucose conditions by activating the TGFβ₁/SNAIL pathway, thus contributing to the development of diabetic cataracts.