Reduced acetylated α-tubulin in SPAST hereditary spastic paraplegia patient PBMCs

• Published in: Frontiers in neuroscience 2023-03, Vol.17, p.1073516-1073516
• Main Authors: Wali, Gautam, Siow, Sue-Faye, Liyanage, Erandhi, Kumar, Kishore R, Mackay-Sim, Alan, Sue, Carolyn M
• Format: Article
• Language: English
• Subjects: Antibodies; Biomarkers; Blood-brain barrier; Brain; Clinical trials; Data analysis; Disease; Flow cytometry; Hereditary spastic paraplegia; Leukocytes (mononuclear); Lymphocytes; microtubule; neurodegenerative disease; Neuroscience; noscapine; Paralysis; Patients; Peripheral blood mononuclear cells; Pharmacodynamics; Reagents; Spasticity; Stem cells; Tubulin
• ISSN: 1662-4548; 1662-453X; 1662-453X
• DOI: 10.3389/fnins.2023.1073516

HSP is the most common form of hereditary spastic paraplegia (HSP), a neurodegenerative disease causing lower limb spasticity. Previous studies using HSP patient-derived induced pluripotent stem cell cortical neurons have shown that patient neurons have reduced levels of acetylated α-tubulin, a form of stabilized microtubules, leading to a chain of downstream effects eventuating in increased vulnerability to axonal degeneration. Noscapine treatment rescued these downstream effects by restoring the levels of acetylated α-tubulin in patient neurons. Here we show that HSP patient non-neuronal cells, peripheral blood mononuclear cells (PBMCs), also have the disease-associated effect of reduced levels of acetylated α-tubulin. Evaluation of multiple PBMC subtypes showed that patient T cell lymphocytes had reduced levels of acetylated α-tubulin. T cells make up to 80% of all PBMCs and likely contributed to the effect of reduced acetylated α-tubulin levels seen in overall PBMCs. We further showed that mouse administered orally with increasing concentrations of noscapine exhibited a dose-dependent increase of noscapine levels and acetylated α-tubulin in the brain. A similar effect of noscapine treatment is anticipated in HSP- patients. To measure acetylated α-tubulin levels, we used a homogeneous time resolved fluorescence technology-based assay. This assay was sensitive to noscapine-induced changes in acetylated α-tubulin levels in multiple sample types. The assay is high throughput and uses nano-molar protein concentrations, making it an ideal assay for evaluation of noscapine-induced changes in acetylated α-tubulin levels. This study shows that HSP- patient PBMCs exhibit disease-associated effects. This finding can help expedite the drug discovery and testing process.