Department of Medical Biotechnology and Translational Medicine, University of Milano, 20122 Milano, Italy.
Blood-Brain Barrier Laboratory, UR2465, Artois University, F-62300 Lens, France.
Int J Mol Sci. 2020 Apr 19;21(8):2858. doi: 10.3390/ijms21082858.
Ganglioside GM1 (GM1) has been reported to functionally recover degenerated nervous system in vitro and in vivo, but the possibility to translate GM1's potential in clinical settings is counteracted by its low ability to overcome the blood-brain barrier (BBB) due to its amphiphilic nature. Interestingly, the soluble and hydrophilic GM1-oligosaccharide (OligoGM1) is able to punctually replace GM1 neurotrophic functions alone, both in vitro and in vivo. In order to take advantage of OligoGM1 properties, which overcome GM1's pharmacological limitations, here we characterize the OligoGM1 brain transport by using a human in vitro BBB model. OligoGM1 showed a 20-fold higher crossing rate than GM1 and time-concentration-dependent transport. Additionally, OligoGM1 crossed the barrier at 4 °C and in inverse transport experiments, allowing consideration of the passive paracellular route. This was confirmed by the exclusion of a direct interaction with the active ATP-binding cassette (ABC) transporters using the "pump out" system. Finally, after barrier crossing, OligoGM1 remained intact and able to induce Neuro2a cell neuritogenesis by activating the TrkA pathway. Importantly, these in vitro data demonstrated that OligoGM1, lacking the hydrophobic ceramide, can advantageously cross the BBB in comparison with GM1, while maintaining its neuroproperties. This study has improved the knowledge about OligoGM1's pharmacological potential, offering a tangible therapeutic strategy.
神经节苷脂 GM1（GM1）已被报道在体外和体内具有功能性的神经退行性病变恢复作用，但由于其两亲性，GM1 跨越血脑屏障（BBB）的能力较低，其在临床环境中的应用潜力受到限制。有趣的是，可溶性和亲水性 GM1-寡糖（OligoGM1）能够单独地、在体外和体内及时替代 GM1 的神经营养功能。为了利用 OligoGM1 的特性来克服 GM1 的药理学限制，我们在这里使用人体外 BBB 模型来表征 OligoGM1 的脑内转运。OligoGM1 的穿膜率比 GM1 高 20 倍，并且具有时间浓度依赖性。此外，OligoGM1 可以在 4°C 下和反向转运实验中穿过屏障，允许考虑被动的细胞旁途径。这通过使用“泵出”系统排除与主动 ATP 结合盒（ABC）转运蛋白的直接相互作用得到证实。最后，OligoGM1 在穿过屏障后保持完整，并能够通过激活 TrkA 途径诱导 Neuro2a 细胞的神经突生成。重要的是，这些体外数据表明，与 GM1 相比，缺乏疏水性神经酰胺的 OligoGM1 可以有利地跨越 BBB，同时保持其神经营养特性。这项研究提高了对 OligoGM1 药理学潜力的认识，提供了一种切实可行的治疗策略。
