The fatty acid binding protein FABP7 is required for optimal oligodendrocyte differentiation during myelination but not during remyelination.

The major constituents of the myelin sheath are lipids, which are made up of fatty acids (FAs). The hydrophilic environment inside the cells requires FAs to be bound to proteins, preventing their aggregation. Fatty acid binding proteins (Fabps) are one class of proteins known to bind FAs in a cell. Given the crucial role of FAs for myelin sheath formation we investigated the role of Fabp7, the major isoform expressed in oligodendrocyte progenitor cells (OPCs), in developmental myelination and remyelination. Here we show that the knockdown of Fabp7 resulted in a reduction of OPC differentiation in vitro. Consistent with this result, a delay in developmental myelination was observed in Fabp7 knockout animals. This delay was transient with full myelination being established before adulthood. Fabp7 was dispensable for remyelination, as the knockout of Fapb7 did not alter remyelination efficiency in a focal demyelination model. In summary, while Fabp7 is important in OPC differentiation in vitro, its function is not crucial for myelination and remyelination in vivo.This work was supported by grants from the UK Multiple Sclerosis Society, the Adelson Medical Research Foundation, the Japan Society for the Promotion of Science (JSPS) KAKENHI Grant and a core support grant from the Wellcome Trust and MRC to the Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute. AGF was also supported by an ECTRIMS postdoctoral fellowship from July 2018. SF and TB were also supported by a Wellcome-Trust PhD studentship