Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
Artificial Axon Labs, Boston, MA, USA.
Sci Rep. 2023 Nov 9;13(1):19529. doi: 10.1038/s41598-023-44675-6.
Multiple sclerosis (MS), a chronic neurodegenerative disease driven by damage to the protective myelin sheath, is currently incurable. Today, all clinically available treatments modulate the immune-mediated symptoms of the disease but they fail to stop neurodegeneration in many patients. Remyelination, the regenerative process of myelin repair by oligodendrocytes, which is considered a necessary step to protect demyelinated axons and stop neuronal death, is impaired in MS patients. One of the major obstacles to finding effective remyelinating drugs is the lack of biomimetic drug screening platforms that enable quantification of compounds' potential to stimulate 3D myelination in the physiologically relevant axon-like environment. To address this need, we built a unique myelination drug discovery platform, by expanding our previously developed technology, artificial axons (AAs), which enables 3D-printing of synthetic axon mimics with the geometry and mechanical properties closely resembling those of biological axons. This platform allows for high-throughput phenotypic myelination assay based on quantification of 3D wrapping of myelin membrane around axons in response to compounds. Here, we demonstrate quantification of 3D myelin wrapping by rat oligodendrocytes around the axon mimics in response to a small library of known pro-myelinating compounds. This assay shows pro-myelinating activity for all tested compounds consistent with the published in vitro and in vivo data, demonstrating predictive power of AA platform. We find that stimulation of myelin wrapping by these compounds is dose-dependent, providing a facile means to quantify the compounds' potency and efficacy in promoting myelin wrapping. Further, the ranking of relative efficacy among these compounds differs in this 3D axon-like environment as compared to a traditional oligodendrocyte 2D differentiation assay quantifying area of deposited myelin membrane. Together, we demonstrate that the artificial axons platform and associated phenotypic myelin wrapping assay afford direct evaluation of myelin wrapping by oligodendrocytes in response to soluble compounds in an axon-like environment, providing a predictive tool for the discovery of remyelinating therapies.
多发性硬化症（MS）是一种由保护性髓鞘损伤驱动的慢性神经退行性疾病，目前尚无治愈方法。如今，所有临床可用的治疗方法都可以调节疾病的免疫介导症状，但在许多患者中，它们都无法阻止神经退行性变。髓鞘再生是少突胶质细胞修复髓鞘的再生过程，被认为是保护脱髓鞘轴突和阻止神经元死亡的必要步骤，但在 MS 患者中受损。找到有效髓鞘再生药物的主要障碍之一是缺乏仿生药物筛选平台，该平台可量化化合物刺激生理相关轴突样环境中 3D 髓鞘形成的潜力。为了满足这一需求，我们通过扩展我们之前开发的技术——人工轴突（AA），构建了一个独特的髓鞘发现药物筛选平台，该技术可以 3D 打印具有与生物轴突几何形状和机械性能非常相似的合成轴突模拟物。该平台允许基于对轴突周围髓鞘膜 3D 包裹的化合物进行高通量表型髓鞘形成测定。在这里，我们通过大鼠少突胶质细胞围绕轴突模拟物对小化合物文库进行 3D 包裹，以证明髓鞘的定量包裹。该测定法显示所有测试化合物均具有促髓鞘形成活性，与已发表的体外和体内数据一致，证明了 AA 平台的预测能力。我们发现这些化合物对髓鞘包裹的刺激作用呈剂量依赖性，这为量化化合物促进髓鞘包裹的效力和功效提供了一种简单的方法。此外，与传统的少突胶质细胞 2D 分化测定法（定量沉积的髓鞘膜面积）相比，这些化合物在这种 3D 轴突样环境中的相对功效排名有所不同。总之，我们证明人工轴突平台和相关的表型髓鞘包裹测定法可在轴突样环境中直接评估少突胶质细胞对可溶性化合物的髓鞘包裹，为髓鞘再生疗法的发现提供了一种预测工具。
