Progesterone Antagonist Therapy in a Pelizaeus-Merzbacher Mouse Mode

Pelizaeus-Merzbacher disease (PMD) is a severe hypomyelinating disease, characterized by ataxia, intellectual disability, epilepsy and premature death. In the majority of cases, PMD is caused by duplication of PLP1 that is expressed in myelinating oligodendrocytes. Despite detailed knowledge of PLP1, there is presently no curative therapy for PMD. We used a Plp1 transgenic PMD mouse model to test the therapeutic effect of Lonaprisan, an antagonist of the nuclear progesterone receptor, in lowering Plp1 mRNA overexpression. We applied placebo-controlled Lonaprisan therapy to PMD mice for 10 weeks and performed the grid slip analysis to assess the clinical phenotype. Additionally, mRNA expression and protein accumulation as well as histological analysis of the central nervous system were performed. While Plp1 mRNA levels are increased about 1.8-fold in PMD mice compared to wildtype controls, daily Lonaprisan treatment reduced overexpression at the RNA level up to 1.5-fold, which was sufficient to significantly improve a poor motor phenotype. Electron microscopy confirmed a 25% increase in the number of myelinated axons in the corticospinal tract when compared to untreated PMD mice. Microarray analysis revealed the upregulation of pro-apoptotic genes in PMD mice that could be partially rescued by Lonaprisan treatment, which also reduced microgliosis, astrogliosis, and lymphocyte infiltration.

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Prukop T, Epplen DB, Nientiedt T, Wichert SP, Fledrich R, Stassart RM, Rossner MJ, Edgar JM, Werner HB, Nave KA, Sereda MW