Alteration of Autophagy and Glial Activity in Nilotinib-Treated Huntington's Disease Patients.

Nilotinib is a tyrosine kinase inhibitor that is safe and tolerated in neurodegeneration, it achieves CSF concentration that is adequate to inhibit discoidin domain receptor (DDR)-1. Nilotinib significantly affects dopamine metabolites, including Homovanillic acid (HVA), resulting in an increase in brain dopamine. HD is a hereditary disease caused by mutations in the Huntingtin's (HTT) gene and characterized by neurodegeneration and motor and behavioral symptoms that are associated with activation of dopamine receptors. We explored the effects of a low dose of nilotinib (150 mg) on behavioral changes and motor symptoms in manifest HD patients and examined the effects of nilotinib on several brain mechanisms, including dopamine transmission and gene expression via cerebrospinal fluid (CSF) miRNA sequencing. Nilotinib, 150 mg, did not result in any behavioral changes, although it significantly attenuated HVA levels, suggesting reduction of dopamine catabolism. There was no significant change in HTT, phosphorylated neuro-filament and inflammatory markers in the CSF and plasma via immunoassays. Whole miRNA genome sequencing of the CSF revealed significant longitudinal changes in miRNAs that control specific genes associated with autophagy, inflammation, microglial activity and basal ganglia neurotransmitters, including dopamine and serotonin.

Safety, target engagement, and biomarker effects of bosutinib in dementia with Lewy bodies.

Introduction: Bosutinib, a dual Abelson/Src inhibitor, was investigated in individuals with dementia with Lewy bodies (DLB). Methods: A single site, randomized, double-blind, placebo-controlled study of the effects of oral bosutinib, 100 mg once daily for 12 weeks on primary safety and pharmacokinetics and secondary biomarker outcomes. Results: Twenty-six participants were randomized and included male and female (12:1) in the bosutinib arm and all male (13) in the placebo arm. The average age was 72.9 ± 8.1 (year ± standard deviation). There were no serious adverse events and no dropouts. Bosutinib was measured in the cerebrospinal fluid (CSF) and inhibited Abelson. Bosutinib reduced CSF alpha-synuclein and dopamine catabolism. Discussion: Bosutinib is safe and well tolerated and penetrates the blood-brain barrier to inhibit Abelson and reduce CSF alpha-synuclein and dopamine catabolism, suggesting that bosutinib (100 mg) may be at or near the lowest effective dose in DLB. These results will guide adequately powered studies to determine the efficacy of a dose range of bosutinib and longer treatment in DLB. Highlights: Bosutinib is a dual Abl/Src inhibitor that penetrates the blood brain barrierBosutinib is safe and tolerated in individuals with dementia with Lewy bodiesBosutinib engages its target via inhibition of Abl and SrcBosutinib reduces CSF alpha-synuclein and attenuates breakdown of dopamineBosutinib improves activities of daily living in dementia with Lewy bodies.

Long-Term Safety and Clinical Effects of Nilotinib in Parkinson's Disease.

BACKGROUND: Nilotinib is US Food and Drug Administration-approved for leukemia, and this open-label study investigated the safety, tolerability, and potential clinical effects of nilotinib in medically optimized patients with Parkinson's disease. OBJECTIVES: Safety and tolerability were the primary objectives, and clinical outcomes were exploratory. METHODS: A total of 63 patients completed a 15-month phase 2, double-blind, placebo-controlled study and were rerandomized 1:1 into an open-label study of nilotinib 150 mg versus 300 mg for 12 months. RESULTS: Nilotinib was safe and tolerated, and no adverse effects seemed to be related to the drug, and no differences in adverse events were observed between groups. Exploratory clinical outcomes showed that nilotinib 300 mg was remarkably stable from baseline to 27 months using partial and total Unified Parkinson's Disease Scale (UPDRS). Nilotinib 150 mg versus 300 mg, significantly declined using partial or the sum of UPDRS Parts I and II. There was no significant difference in nilotinib 150 mg versus 300 mg using UPDRS Part III (on levodopa) and total UPDRS Parts I to III. Subgroup analysis showed that late-start nilotinib 150 mg significantly worsened using the sum of UPDRS Parts II + III and total UPDRS Parts I to III compared with late-start nilotinib 300 mg. Quality of life using the Parkinson's Disease Questionnaire in nilotinib 150 mg significantly declined between 15 and 27 months compared with nilotinib 300 mg, and there was no change in cognition using the Montreal Cognitive Assessment between groups. CONCLUSIONS: This study provides evidence that nilotinib is safe and tolerated in Parkinson's disease. The exploratory clinical data will inform an adequately powered larger study to evaluate the efficacy of nilotinib 300 mg in Parkinson's disease. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Nilotinib Effects on Safety, Tolerability, and Biomarkers in Alzheimer's Disease.

OBJECTIVE: Preclinical evidence with nilotinib, a US Food and Drug Administration (FDA)-approved drug for leukemia, indicates improvement in Alzheimer's disease phenotypes. We investigated whether nilotinib is safe, and detectable in cerebrospinal fluid, and alters biomarkers and clinical decline in Alzheimer's disease. METHODS: This single-center, phase 2, randomized, double-blind, placebo-controlled study investigated the safety, tolerability, and pharmacokinetics of nilotinib, and measured biomarkers in participants with mild to moderate dementia due to Alzheimer's disease. The diagnosis was supported by cerebrospinal fluid or amyloid positron emission tomography biomarkers. Nilotinib 150 mg versus matching placebo was taken orally once daily for 26 weeks followed by nilotinib 300 mg versus placebo for another 26 weeks. RESULTS: Of the 37 individuals enrolled, 27 were women and the mean (SD) age was 70.7 (6.48) years. Nilotinib was well-tolerated, although more adverse events, particularly mood swings, were noted with the 300 mg dose. In the nilotinib group, central nervous system (CNS) amyloid burden was significantly reduced in the frontal lobe compared to the placebo group. Cerebrospinal fluid Aß40 was reduced at 6 months and Aß42 was reduced at 12 months in the nilotinib group compared to the placebo. Hippocampal volume loss was attenuated (-27%) at 12 months and phospho-tau-181 was reduced at 6 months and 12 months in the nilotinib group. INTERPRETATION: Nilotinib is safe and achieves pharmacologically relevant cerebrospinal fluid concentrations. Biomarkers of disease were altered in response to nilotinib treatment. These data support a larger, longer, multicenter study to determine the safety and efficacy of nilotinib in Alzheimer's disease. ANN NEUROL 2020 ANN NEUROL 2020;88:183-194.

Ubiquitin Specific Protease 13 Regulates Tau Accumulation and Clearance in Models of Alzheimer's Disease.

Ubiquitin Specific Protease-13 (USP13) is a de-ubiquinating enzyme that regulates protein ubiquitination and clearance. The role of USP13 is largely unknown in neurodegeneration. In this study we aim to demonstrate whether tau accumulation and/or clearance depends on ubiquitination/de-ubiquitination via USP-13. We used transgenic animal models of human amyloid precursor protein (APP) or P301L tau mutations and genetically knocked-down USP13 expression via shRNA to determine USP13 effects on tau ubiquitination and levels. We found a two-fold increase of USP13 levels in postmortem Alzheimer's disease (AD) brains. USP13 knockdown significantly increased the activity of the 20S proteasome and reduced the levels of hyper-phosphorylated tau (p-tau) in primary cortical neurons. USP13 knockdown also reduced the levels of amyloid and increased p-tau ubiquitination and clearance in transgenic animal models that overexpress murine tau as a result of the expression of familial APP mutations (TgAPP) and the human mutant P301L tau (rTg4510), respectively. Clearance of p-tau appears to be mediated by autophagy in these animal models. Taken together, these data suggest that USP13 knockdown reduces p-tau accumulation via regulation of ubiquitination/de-ubiquitination and mediates its clearance via autophagy and/or the proteasome. These results suggest that USP13 inhibition may be a therapeutic strategy to reduce accumulation of plaques and toxic p-tau in AD and human tauopathies.