A human-induced pluripotent stem cell-derived spheroid model to investigate myelin injury and repair.

A human iPSC-derived spheroid model reveals that remyelinated axons have thinner myelin sheaths after injury, advancing understanding of human myelin repair mechanisms.

• Why it matters: Current therapies lack the ability to promote new myelin formation, partly due to the absence of reliable models that mimic human myelin damage and repair processes, hindering drug development.
• What they did: The researchers engineered a human iPSC-derived spheroid system containing mature oligodendrocytes and reactive microglia, enabling the study of demyelination and remyelination through processes like myelin fragmentation, microglial activity, and oligodendrocyte differentiation.
• The result: The model demonstrated that newly generated oligodendrocytes contribute to remyelination, with ultrastructural analysis showing that remyelinated axons are ensheathed by thinner myelin, providing a platform for mechanistic studies and drug screening in multiple sclerosis.