Fingolimod and remyelination - Fingolimod downregulates brain sphingosine-1-phosphate receptor 1 levels but does not promote remyelination or neuroprotection in the cuprizone model

Remyelinating substances could be an essential supplement to immunomodulatory medications, optimizing the treatment of multiple sclerosis (MS) patients. Fingolimod is a sphingosine-1-phosphate receptor (S1PR) modulator and crosses the blood-brain barrier. Central nervous system (CNS) cells express S1PRs, and Fingolimod could theoretically improve CNS remyelination and be neuroprotective per se, but data are inconsistent. We used the cuprizone model for investigating the effect of fingolimod on remyelination and axonal damage by Immunohistochemistry and quantitative mass spectrometry. After three weeks of remyelination, fingolimod-treated mice had more mature oligodendrocytes in the secondary motor cortex than the placebo group. However, fingolimod did not at any time point affect remyelination or axonal damage. We conclude that fingolimod does not promote remyelination or protect against axonal injury or loss after cuprizone exposure.