State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University , 199 Ren'ai Road, Suzhou 215123, P.R. China.
Center for Soft Condensed Matter Physics and Interdisciplinary Research, Soochow University , Suzhou 215006, P.R. China.
ACS Appl Mater Interfaces. 2017 Apr 5;9(13):11518-11527. doi: 10.1021/acsami.7b01397. Epub 2017 Mar 24.
To realize the potential application of embryonic stem cells (ESCs) for the treatment of neurodegenerative diseases, it is a prerequisite to develop an effective strategy for the neural differentiation of ESCs so as to obtain adequate amount of neurons. Considering the efficacy of glycosaminoglycans (GAG) and their disadvantages (e.g., structure heterogeneity and impurity), GAG-mimicking glycopolymers (designed polymers containing functional units similar to natural GAG) with or without phospholipid groups were synthesized in the present work and their ability to promote neural differentiation of mouse ESCs (mESCs) was investigated. It was found that the lipid-anchored GAG-mimicking glycopolymers (lipo-pSGF) retained on the membrane of mESCs rather than being internalized by cells after 1 h of incubation. Besides, lipo-pSGF showed better activity in promoting neural differentiation. The expression of the neural-specific maker β3-tubulin in lipo-pSGF-treated cells was ∼3.8- and ∼1.9-fold higher compared to natural heparin- and pSGF-treated cells at day 14. The likely mechanism involved in lipo-pSGF-mediated neural differentiation was further investigated by analyzing its effect on fibroblast growth factor 2 (FGF2)-mediated extracellular signal-regulated kinases 1 and 2 (ERK1/2) signaling pathway which is important for neural differentiation of ESCs. Lipo-pSGF was found to efficiently bind FGF2 and enhance the phosphorylation of ERK1/2, thus promoting neural differentiation. These findings demonstrated that engineering of cell surface glycan using our synthetic lipo-glycopolymer is a highly efficient approach for neural differentiation of ESCs and this strategy can be applied for the regulation of other cellular activities mediated by cell membrane receptors.
为了实现胚胎干细胞（ESCs）在治疗神经退行性疾病中的潜在应用，开发一种有效的 ESC 神经分化策略以获得足够数量的神经元是前提。考虑到糖胺聚糖（GAG）的功效及其缺点（例如结构异质性和杂质），本工作合成了具有或不具有磷脂基团的 GAG 模拟糖聚合物（设计的聚合物，其包含与天然 GAG 相似的功能单元），并研究了其促进小鼠胚胎干细胞（mESCs）神经分化的能力。结果发现，脂质锚定的 GAG 模拟糖聚合物（lipo-pSGF）在孵育 1 小时后保留在 mESC 的膜上，而不是被细胞内化。此外，lipo-pSGF 显示出更好的促进神经分化的活性。在用 lipo-pSGF 处理的细胞中，神经特异性标志物 β3-微管蛋白的表达在第 14 天与天然肝素和 pSGF 处理的细胞相比分别高约 3.8 倍和 1.9 倍。通过分析其对成纤维细胞生长因子 2（FGF2）介导的细胞外信号调节激酶 1 和 2（ERK1/2）信号通路的影响，进一步研究了 lipo-pSGF 介导的神经分化的可能机制，该信号通路对 ESCs 的神经分化很重要。发现 lipo-pSGF 有效地结合 FGF2 并增强 ERK1/2 的磷酸化，从而促进神经分化。这些发现表明，使用我们的合成 lipo-糖聚合物对细胞表面聚糖进行工程改造是一种高效的 ESCs 神经分化方法，该策略可应用于通过细胞膜受体介导的其他细胞活动的调节。
