Identification and evaluation of potential remyelination therapeutics for multiple sclerosis (S9.006)

OBJECTIVE: To identify and evaluate small molecule compounds for use as remyelination therapeutics. BACKGROUND: A primary pathological feature of multiple sclerosis is the loss of myelin-producing OL and myelin sheaths, resulting in axonal loss and irreversible neurological decline. Although there are plenty of oligodendrocyte progenitor cells (OPCs) within MS lesions, the efficiency of spontaneous generation of OL declines dramatically with every episode of demyelination. Therapeutic intervention to stimulate differentiation of OL and remyelination has the potential to reverse functional decline in MS patients. DESIGN/METHODS: Compounds were screened in a high-content, cell-based screening system for the ability to promote the differentiation of OPCs, derived from E14.5 PLP-EGFP embryos, into oligodendrocytes in 96 well plates. RESULTS: We optimized the screening system with thyroid hormone T3 to achieve a consistently positive Z9 score and repeatable results. Using this system, we identified 45 hits with EC50 lower than 1uM after screening a library containing 20,000 small molecules. The effect of these hits was confirmed in secondary screening using oligodendrocyte markers O4 and MBP. These hits belong to at least six distinct chemical structural groups, with the lead compound having an EC50 of ~30nM. Western blotting analysis confirmed increased expression of oligodendrocyte differentiation markers, including PLP, CNPase, and MBP, as early as 24hr at levels similar to or higher than our positive control T3. The lead compound has low animal toxicity and good brain penetration. In addition, pathway perturbation studies and gene expression studies suggested that the lead compound functions upstream of the AKT pathway to regulate OL differentiation. CONCLUSIONS: We have identified several small molecule leads that can induce differentiation of oligodendrocytes with high efficacy and low toxicity. These leads have the potentials to be developed into remyelination therapeutics to fill unmet needs of MS patients. Study Supported by: NIH Disclosure: Dr. Bai has received personal compensation for activities with Renovo Neural Inc. as an employee. Dr. Lunn has received personal compensation for activities with Renovo Neural as an employee. Dr. Avila has nothing to disclose. Dr. Medicetty has received personal compensation for activities with Renovo Neural as an employee. Dr. Trapp has received personal compensation for activities with Renovo Neural, Teva Neuroscience, Biogen Idec, Endece, Merck & Co., Inc., EMD Serono, and Novartis.