A human pluripotent stem-cell derived in-vitro model of myelination

Owen Gwydion James 1,2, Dario Magnani 1,2, Bhuvaneish T. Selvaraj 1,2, Navneet Vasistha 1,2, Samantha Barton 1,2, David Story 1,2, Karen Burr 1,2, Charles ffrench-Constant 1, Siddharthan Chandran 1,2

  1. MRC Centre for Regenerative Medicine, University of Edinburgh
  2. Centre for Clinical Brain Sciences, Chancellor’s Building, University of Edinburgh

Oligodendrocytes myelinate axons of the central nervous system (CNS). The myelin sheath enables saltatory conduction of action potentials and provides metabolic support to the underlying axon. Demyelination is the pathological loss of myelin, compromising neuronal function, and is central to a number of diseases, including multiple sclerosis. Remyelination can restore neuronal function and involves the differentiation of oligodendrocyte progenitors into myelin forming cells, which subsequently ensheath denuded axons. However, the majority of MS patients exhibit inefficient repair, leading to an accumulation of neurodegeneration with disease progression. Promoting endogenous remyelination may be a putative therapy for progressive MS, which currently cannot be treated.

There is a need for a human-based in-vitro model of myelination to complement current systems and accelerate drug discovery. Additionally, such a model would permit investigation of disease-causing mutations on myelin formation. We derived oligodendroglia from induced pluripotent stem cells by specifying a ventral neuro-epithelial identity followed by patterning with PDGFa and FGF2. These 3D culture spheres contained NF-H+ neurons, GFAP+ astrocytes, PDGFRa+ progenitor cells and MBP+ oligodendrocytes. Cultures showed increasing levels of myelin up to 12 weeks, identified by MBP+ segments co-localising with NF-H+ axons and paranodal markers such as CASPR and CLAUDIN-11. Compact myelin lamellae could be seen by transmission electron microscopy. Myelination efficiency was calculated as the ratio of number of myelin sheaths to the number of NOGOA+SOX10+ double positive cells. The proportion of mature oligodendrocytes was identified as the ratio of NOGOA+SOX10+ double positive cells to the total number of SOX10+ cells.

Future experiments will validate pro-myelinating compounds, using the parameters described above. This will enable us to differentiate whether such compounds act upon oligodendrocyte differentiation, or the propensity of myelination. This model can also be used for other neurological disorders where myelin perturbations have been described, such as amyotrophic lateral sclerosis.

Funded by: Euan MacDonald Centre, University of Edinburgh College of Medicine and Veterinary Medicine

* entered into the PhD student poster competition