Fu Lanfang, Zhang Juyun, Lin Zhu, Meng Xubiao
Department of Endocrinology, Haikou People's Hospital, Haikou, China.
J Diabetes Investig. 2025 Aug;16(8):1371-1381. doi: 10.1111/jdi.70082. Epub 2025 May 22.
Islet β-cell dedifferentiation is a major pathological mechanism of type 2 diabetes (T2D). Forkhead box o1 (Foxo1) is a master regulator of β-cell dedifferentiation. The mechanisms by which Foxo1 expression is regulated remain unexplored. Epigenetic modification is involved in the occurrence and development of T2D. Ubiquitin-like with PDH and ring finger domains 1 (Uhrf1), as an important epigenetic regulator, is associated with the maintenance of DNA methylation and histone modification.
This study aimed to discover whether Uhrf1 regulates Foxo1 expression and β-cell dedifferentiation of rat insulinoma (INS-1) cells.
RT-qPCR and Western blot were performed to detect the levels of Uhrf1, Foxo1, β-cell dedifferentiation, and proliferation and apoptosis related indicators. ChIP-qPCR was used to analyze the relative lysine trimethylation at positions 4, 9, and 27 on histone H3 (H3K4/9/27me3) enrichment on the Foxo1 promoter. Dual-luciferase reporter assay was performed to assess the interaction between Uhrf1 and Foxo1. Finally, a diabetic rat model was established and the rat islet β-cells were isolated.
Glucolipotoxicity-induced β-cell dedifferentiation of INS-1 cells, which was restored after Uhrf1 overexpression. Mechanistically, Uhrf1 regulated the H3K4/9/27me3 of the Foxo1 promoter region. Besides, Foxo1 overexpression suppressed β-cell dedifferentiation of INS-1 cells. Moreover, islet β-cells isolated from diabetic model rats showed increased dedifferentiation.
Uhrf1 knockdown promoted H3K27me3 and H3K9me3 and reduced H3K4me3 level in INS-1 cells, resulting in the downregulation of Foxo1 expression, thus promoting β-cell dedifferentiation.
胰岛β细胞去分化是2型糖尿病（T2D）的主要病理机制。叉头框蛋白O1（Foxo1）是β细胞去分化的主要调节因子。Foxo1表达的调控机制尚不清楚。表观遗传修饰参与了T2D的发生和发展。泛素样与丙酮酸脱氢酶和环指结构域1（Uhrf1）作为一种重要的表观遗传调节因子，与DNA甲基化和组蛋白修饰的维持有关。
本研究旨在探讨Uhrf1是否调节大鼠胰岛素瘤（INS-1）细胞中Foxo1的表达和β细胞去分化。
采用RT-qPCR和蛋白质免疫印迹法检测Uhrf1、Foxo1、β细胞去分化以及增殖和凋亡相关指标的水平。染色质免疫沉淀-定量聚合酶链反应（ChIP-qPCR）用于分析组蛋白H3第4、9和27位赖氨酸三甲基化（H3K4/9/27me3）在Foxo1启动子上的富集情况。采用双荧光素酶报告基因检测法评估Uhrf1与Foxo1之间的相互作用。最后，建立糖尿病大鼠模型并分离大鼠胰岛β细胞。
糖脂毒性诱导INS-1细胞β细胞去分化，Uhrf1过表达后恢复。机制上，Uhrf1调节Foxo1启动子区域的H3K4/9/27me3。此外，Foxo1过表达抑制INS-1细胞β细胞去分化。而且，从糖尿病模型大鼠分离的胰岛β细胞显示出去分化增加。
Uhrf1基因敲低促进了INS-1细胞中H3K27me3和H3K9me3的表达，降低了H3K4me3水平，导致Foxo1表达下调，从而促进β细胞去分化。
