Accelerating remyelination using lanthionine ketimine derivatives

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The major goal of this project is to identify novel compounds which will accelerate remyelination within the CNS of patients with Multiple Sclerosis (MS). While many therapies have been developed to treat MS, almost all target the immune system in efforts to reduce ongoing damage; in contrast relatively few target the regenerative capacity of myelin producing Oligodendrocytes (OLGs) to restore function. In ongoing studies to characterize the beneficial effects of Lanthionine Ketimine Ester (LKE), a semi-synthetic amino acid derivative, we found that LKE not only reduces clinical signs in a mouse model of MS, but also accelerates remyelination following chemically induced, non-inflammatory demyelination by cuprizone (CPZ). In vitro screening of new LKE derivatives suggests some are more potent than the parent compound. This raises the main hypothesis that LKE and new derivatives will increase remyelination and restore functional outcomes. This will be addressed in the following aims: Aim 1: Extend our initial studies of LKE benefit using the CPZ model, including optimization of LKE dosage and duration; and comparisons of LKE following modest (CPZ for 2 weeks) or extensive (CPZ for 5-9 weeks) stages of demyelination. Assessments will include electron and confocal microscopy of myelin, axons, and Nodes of Ranvier; analysis of OPC maturation; neuronal damage; and glial inflammation. Aim 2: Characterize LKE-treatment induced improvement on functional outcomes, including improvement in nerve conductance by recording compound action potentials across the corpus callosum; and behavioral analysis to assess motor and balance improvement with rotarod; novel object recognition to assess memory and anxiety; and y-maze to assess memory. Aim 3: Complete screening of 4 lead LKE-derivatives to identify those having the highest efficacy (lowest dosage, more rapid or robust increase) to induce OPC maturation, best metabolic stability, and highest membrane permeability. The best candidate will be tested in the CPZ model and directly compared to LKE. Aim 4: Use in vivo and in vitro experiments to explore mechanisms of action of LKE and derivatives. This will include electrophysiological methods and calcium imaging to examine effects of LKE on CRMP2, and its interactions with Voltage Gated Ca2+ Channels (VGCCs) in OPCs. Available conditional knockout mice for CRMP2 will allow testing if CRMP2 in OPCs mediates LKE actions.