College of Pharmacy, Chungbuk National University, Osongsaengmyeong 1-ro, Heungduk-gu, Cheongju, Republic of Korea.
College of Pharmacy, Chungbuk National University, Osongsaengmyeong 1-ro, Heungduk-gu, Cheongju, Republic of Korea.
Life Sci. 2024 Apr 1;342:122534. doi: 10.1016/j.lfs.2024.122534. Epub 2024 Feb 24.
Sphingolipids are involved in the regulation of insulin signaling, which is linked to the development of insulin resistance, leading to diabetes mellitus. We aimed to study whether modulation of sphingolipid levels by GT-11 may regulate insulin signaling in C2C12 myotubes.
We investigated the effects of sphingolipid metabolism on Akt phosphorylation and glucose uptake using C2C12 myotubes. Either GT-11, an inhibitor of dihydroceramide desaturase 1 and S1P lyase, or siRNA targeting Sgpl1, the gene encoding the enzyme, was employed to determine the effect of sphingolipid metabolism modulation on insulin signaling. Western blotting and glucose uptake assays were used to evaluate the effect of treatments on insulin signaling. Sphingolipid metabolites were analyzed by high performance liquid chromatography (HPLC).
Treatment with GT-11 resulted in decreased Akt phosphorylation and reduced glucose uptake. Silencing the Sgpl1 gene, which encodes S1P lyase, mimicked these findings, suggesting the potential for regulating insulin signaling through S1P lyase modulation. GT-11 modulated sphingolipid metabolism, inducing the accumulation of sphingolipids. Using PF-543 and ARN14974 to inhibit sphingosine kinases and acid ceramidase, respectively, we identified a significant interplay between sphingosine, S1P lyase, and insulin signaling. Treatment with either exogenous sphingosine or palmitic acid inhibited Akt phosphorylation, and reduced S1P lyase activity.
Our findings highlight the importance of close relationship between sphingolipid metabolism and insulin signaling in C2C12 myotubes, pointing to its potential therapeutic relevance for diabetes mellitus.
神经酰胺是胰岛素信号转导的调节因子，与胰岛素抵抗的发展有关，导致糖尿病。我们旨在研究 GT-11 是否可以通过调节神经酰胺水平来调节 C2C12 肌管中的胰岛素信号。
我们使用 C2C12 肌管研究了神经酰胺代谢对 Akt 磷酸化和葡萄糖摄取的影响。用 GT-11（二氢神经酰胺去饱和酶 1 和 S1P 裂解酶的抑制剂）或靶向编码酶 Sgpl1 的 siRNA 来确定神经酰胺代谢调节对胰岛素信号的影响。使用 Western blot 和葡萄糖摄取测定来评估处理对胰岛素信号的影响。通过高效液相色谱法（HPLC）分析神经酰胺代谢物。
GT-11 处理导致 Akt 磷酸化减少和葡萄糖摄取减少。沉默编码 S1P 裂解酶的 Sgpl1 基因模拟了这些发现，表明通过 S1P 裂解酶调节可能调节胰岛素信号。GT-11 调节神经酰胺代谢，诱导神经酰胺积累。使用 PF-543 和 ARN14974 分别抑制鞘氨醇激酶和酸性神经酰胺酶，我们确定了鞘氨醇、S1P 裂解酶和胰岛素信号之间的显著相互作用。用外源性鞘氨醇或棕榈酸处理抑制 Akt 磷酸化，并降低 S1P 裂解酶活性。
我们的发现强调了 C2C12 肌管中神经酰胺代谢与胰岛素信号之间的密切关系的重要性，指出其对糖尿病的潜在治疗意义。
