A central nervous system axonal myelination assay for high-throughput screening

The formation of new myelin in persistent multiple sclerosis (MS) lesions is compromised, leading to a reduction in neuron function and subject to degeneration and death. Current MS therapies can control autoimmune-mediated demyelination, but none directly promote the regeneration of myelin in the central nervous system (CNS). To identify new drugs that stimulate remyelination, we established a high-throughput cell-based assay to identify compounds that promote myelination. Methods were developed for initiating myelination in vitro using a preparation of primary embryonic rat cortical cells. We developed an immunofluorescent phenotypic image analysis method to quantify the morphological alignment of myelin characteristic of the initiation of myelination. The assay scalability and consistency was validated by screening the NIH clinical collection library of 727 compounds and identified ten compounds that promote myelination (Lariosa-Willingham et al., BMC Neurosci 17:16, 2016). Here, we present the detailed methods for a high capacity in vitro assay that assesses myelination of live axons.