Mitoxantrone Hydrochloride Targets APP and LRRK2 to Improve Neurodegeneration in Parkinson's Models

BackgroundParkinsons disease (PD) is the second common neurodegenerative disorder, driven by the loss of dopaminergic neurons and pathological -synuclein protein accumulation. Currently, there is no disease-modifying therapy that can halt PD progression. Our previous study uncovered a critical pathogenic feed-forward loop between amyloid precursor protein (APP) and leucine-rich repeat kinase 2 (LRRK2), in which the two proteins mutually enhance each others expression, ultimately leading to mitochondrial dysfunction and neurotoxicity. Targeting this vicious cycle represents a promising therapeutic strategy for PD. MethodsTo discover novel inhibitors targeting this axis, we performed high-throughput screening of an FDA-approved drug library using a fluorescence-based biosensor system. We identified Mitoxantrone hydrochloride (MH), an antineoplastic agent, as a lead compound that inhibits both APP and LRRK2 expression. Its efficacy was validated in cellular models, including patient induced pluripotent stem cell (iPSC)-derived dopaminergic neurons and human peripheral blood mononuclear cells (PBMCs). Motor behavioural and safety assessments were subsequently conducted in PD mouse models. ResultsWe demonstrated that MH suppresses both APP and LRRK2 expression in various cell types in a dosage-dependent manner. In addition, MH also inhibits phosphorylation of LRRK2 and its downstream substrate Rab10. We further showed MH inhibits LRRK2 activity through direct binding to its kinase domain. Critically, MH treatment rescued dopaminergic neuron loss and reversed motor deficits in both 6-Hydroxydopamine (6-OHDA)-induced and LRRK2G2019S genetic PD mouse models. Moreover, we found that oral administration of MH is therapeutically effective, providing superior neuroprotection and behavioral recovery without detectable cardiotoxicity or gastrointestinal damage. ConclusionsOur findings demonstrate MH as a compelling, repurposable therapeutic candidate capable of disrupting a core pathogenic mechanism in PD.