The Department of Obstetrics, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Rd., Chongqing, 400016, China.
Chongqing Key Laboratory of Maternal and Fetal Medicine, Chongqing Medical University, Chongqing, 400016, China.
Mol Med. 2023 Feb 20;29(1):23. doi: 10.1186/s10020-023-00615-8.
Gestational diabetes Mellitus (GDM) is a common pregnancy-specific disease with high morbidity, which is linked to a high risk of obesity and diabetes in offspring. N6-methyladenosine modification of RNA is emerging as an important epigenetic mechanism that is widely manifested in many diseases. This study aimed to investigate the mechanism of m6A methylation in metabolic syndrome in offspring result from intrauterine hyperglycemia.
GDM mice were established by feeding a high-fat diet 1 weeks before pregnancy. The m6A RNA methylation quantification kit was used to detect liver tissue methylation levels. PCR array was used to determine the expression of the m6A methylation modification enzyme. Immunohistochemistry, qRT-PCR, and western blot were used to examine the expression of RBM15, METTL13, IGF2BP1, and IGF2BP2. Subsequently, methylated RNA immunoprecipitation sequencing combined with mRNA sequencing, followed by dot blot and glucose uptake tests, were performed.
In this study, we found that offspring from a GDM mother were more vulnerable to glucose intolerance and insulin resistance. GC-MS revealed significant metabolic changes including saturated fatty acids and unsaturated fatty acids in liver of GDM offspring. We also demonstrated that global mRNA m6A methylation level was significantly increased in the fetal liver of GDM mice, indicating epigenetic change may have a strong relationship with the mechanism of metabolism syndrome. Concordantly, RBM15, the RNA binding methyltransferase, was upregulated in the liver. In vitro, RBM15 suppressed insulin sensitivity and increased insulin resistance through m6A-regulated epigenetic inhabitation of CLDN4. Moreover, MeRIP-sequencing and mRNA-sequencing revealed that differently regulated genes with differential m6A peaks were enriched in metabolic pathways.
Our study revealed the essential role of RBM15 in insulin resistance and the effect of RBM15-regulated m6A modification in the metabolic syndrome of offspring of GDM mice.
妊娠糖尿病（GDM）是一种常见的妊娠特异性疾病，发病率高，与后代肥胖和糖尿病的风险增加有关。RNA 的 N6-甲基腺苷修饰作为一种重要的表观遗传机制，广泛表现在许多疾病中。本研究旨在探讨宫内高血糖导致后代代谢综合征中 m6A 甲基化的机制。
在怀孕前 1 周用高脂肪饮食建立 GDM 小鼠模型。使用 m6A RNA 甲基化定量试剂盒检测肝组织甲基化水平。PCR 阵列用于确定 m6A 甲基化修饰酶的表达。免疫组织化学、qRT-PCR 和 Western blot 用于检测 RBM15、METTL13、IGF2BP1 和 IGF2BP2 的表达。随后进行甲基化 RNA 免疫沉淀测序结合 mRNA 测序，再进行点印迹和葡萄糖摄取试验。
本研究发现，GDM 母亲的后代更容易出现葡萄糖不耐受和胰岛素抵抗。GC-MS 显示 GDM 后代肝脏中存在显著的代谢变化，包括饱和脂肪酸和不饱和脂肪酸。我们还表明，GDM 小鼠胎儿肝脏中的全局 mRNA m6A 甲基化水平显著增加，表明表观遗传变化可能与代谢综合征的机制密切相关。相应地，RNA 结合甲基转移酶 RBM15 在肝脏中上调。在体外，RBM15 通过 m6A 调节的 CLDN4 表观遗传抑制作用抑制胰岛素敏感性并增加胰岛素抵抗。此外，MeRIP-seq 和 mRNA-seq 显示，具有不同 m6A 峰的差异调节基因富集在代谢途径中。
本研究揭示了 RBM15 在胰岛素抵抗中的重要作用以及 RBM15 调节的 m6A 修饰在 GDM 小鼠后代代谢综合征中的作用。
