In vitro myelination assay modeling the environment of MS lesions for predictive discovery of remyelinating therapies.

Project Summary Artificial Axon Labs Inc. (AAL), an MIT spinout, is developing a transformative drug screening platform, Artificial Axons, to discover first-in-class remyelinating therapies for currently incurable myelin diseases, with the primary focus on multiple sclerosis (MS). Current disease modifying therapies for MS prevent the formation of new inflammatory lesions in the central nervous system (CNS), but the majority of prior lesions fail to remyelinate and there are no clinically available therapies to promote remyelination and prevent neurodegeneration. One of the major roadblocks in the discovery of remyelinating drugs is the lack of biomimetic drug screening tools that can quantify myelination in response to screened compounds, and do it in the conditions that mimic the environment of demyelinating MS lesions, which often contain factors that inhibit myelin repair. Assays based on tissues or co-cultures of neurons with oligodendrocytes are too complex for effective drug screening. Current screening methods typically rely on 2-dimensional assays that can only evaluate compounds’ potential to stimulate differentiation of oligodendrocytes (myelinating cells in the CNS), but not an actual process of myelin wrapping, which requires 3-dimensional axon-like structures. Existing in vitro 3D myelination assays such as glass cones or electrospun fibers are made of materials several orders of magnitude stiffer than the nervous tissue, and therefore provide unphysiological environment to myelinating cells. As the result, remyelinating drug candidates discovered with these insufficient tools so far have limited success in the clinic. To address this urgent need, AAL is developing Artificial Axons, a novel biomimetic 3D-printed drug discovery platform for remyelinating compounds. Unlike any other platform, our platform enables remyelinating drug screening by direct visualization and quantification of myelin wrapping in response to compounds in the MS lesion-like environment. We create this environment by combining 3D-printed axon mimics, matching the geometry and low mechanical stiffness of biological axons, with key pro-inflammatory soluble factors, which inhibit myelination in MS lesions (interferon gamma and myelin debris). These critical advantages over existing assays make our platform a superior tool for the discovery of remyelinating compounds. In this project we focus on two milestones: 1) developing a myelination assay, which includes common inflammatory factors that inhibit myelin repair in MS lesions (interferon gamma and myelin debris), and 2) validating the new assay by testing how the efficacy of known pro-myelinating compounds changes in the hostile environment of MS lesions. Achieving these milestones will advance our technology on the path to commercialization and accelerate the discovery of remyelinating treatments for MS and other myelin diseases.