Development of a Human Preclinical Platform for the Identification of Neuroprotective Compounds

Multiple sclerosis (MS) is the most common inflammatory and demyelinating disease affecting the central nervous system (CNS). While immune-modulating drugs can prevent new lesions by targeting lymphocyte activity, treating relapse-independent disease progression remains challenging. Persisting CNS inflammation, leading to axonal and neuronal injury along with failure of compensatory mechanisms, such as brain plasticity and remyelination, drives disease progression. Thus, identifying neuroprotective and/or remyelination-promoting compounds is urgently needed. We developed an in vitro platform utilizing human-induced pluripotent stem cell (iPSC)-derived neurons and oligodendrocytes to assess neuroprotective and potentially promyelinating effects of selected compounds. We established assays mimicking MS pathophysiologies, such as neuronal loss and axonal injury. Proteomic analysis revealed modulation of molecular mechanisms. Findings were validated in an acute cuprizone (CPZ) mouse model. We demonstrated that pioglitazone and minocycline protected against glutamate-induced axonal injury, rotenone-induced neuronal death and promoted oligodendrocyte differentiation. Proteomic analyses suggest that pioglitazone's neuroprotective effect may involve reducing mitochondrial reactive oxygen species (ROS) production via PGC-1α and stabilizing axonal transport through GSK3β phosphorylation. Minocycline mainly impacted glutathione metabolism. In the cuprizone model, both compounds displayed neuroprotective effects but did not reduce demyelination or oligodendroglial loss. In summary, our findings demonstrate that human preclinical IPSC platforms can be used to characterize the neuroprotective properties of compounds and thus may aid the selection of drugs for clinical trials. Moreover, the platform's flexibility allows for the easy incorporation of additional disease-specific phenotypic assays.