Spironolactone Targets Retinoid X Receptor γ to Promote Myelin Sheath Regeneration.

BACKGROUND AND OBJECTIVES: Demyelinating diseases are neurologic disorders characterized by the loss of the myelin sheath and impaired regeneration. Retinoid X receptor γ (RXRγ) is a member of the nuclear receptor superfamily and plays a crucial role in oligodendrocyte biology and myelin formation. However, the clinical application of drugs targeting RXRγ for demyelinating diseases is limited. Selecting small-molecule drugs approved by the U.S. Food and Drug Administration (FDA) that have high binding activity to RXRγ may be an effective strategy for treating demyelinating disorders. METHODS: We used an online molecular docking tool to predict that spironolactone (SPIR), an FDA-approved drug, displays strong binding activity to RXRγ. Subsequently, we verified the impact of SPIR on oligodendrocyte precursor cell (OPC) differentiation and myelin sheath formation through in vitro OPC culture and pharmacologic experiments in mice. Furthermore, using genetic models with CRISPR-LSL-Cas9, we confirmed that the effect of SPIR on OPCs relies on RXRγ. RESULTS: In this study, we identified that SPIR, an FDA-approved drug, functions as an RXRγ agonist in OPCs. RXRγ was identified as a crucial factor of myelin production. Its activation promotes the differentiation of OPCs and enhances myelin generation. We confirmed the specificity of SPIR's target, demonstrating that SPIR facilitates OPC differentiation and myelin generation in a RXRγ-dependent manner. Our findings not only identify the RXRγ agonist to promote OPC differentiation but also provide new experimental evidence for expanding the clinical indications of SPIR. DISCUSSION: The promotion of OPC differentiation by SPIR in animal models suggests its potential for treating demyelinating diseases.