Journal: bioRxiv
Article Title: Genotype–Phenotype Distinctions in Spastic Paraplegia 4 Reveal HDAC6 as a Therapeutic Target
doi: 10.1101/2025.07.15.664947
Figure Lengend Snippet: A. Representative immunofluorescent images of 3- and 6-month MCOs derived from SPAST WT/WT , SPAST WT/S245X and SPAST WT/C448Y lines, untreated or treated with the HDAC6 inhibitor Tub A, stained for acetylated tubulin and βIII-tubulin. B-C. Quantification of the acetylated tubulin to βIII-tubulin ratio in 3-month (B) and 6-month (C) MCOs (n=3-6). Tub A significantly increased tubulin acetylation in mutant MCOs. D. Representative immunofluorescent images of 3- and 6-month-old MCOs from SPAST WT/WT , SPAST WT/S245X and SPAST WT/C448Y lines, untreated or treated with TubA, stained for SMI32 (a marker of early axonal degeneration) and βIII-tubulin. E-F. Quantification of the SMI32 to βIII-tubulin ratio in individual axons from 3-month (n=8, E) and 6-month (n=10, F) MCOs. Tub A treatment significantly reduced SMI32 levels in mutant organoids. G-H. Quantification of HDAC6 enzymatic activity in 3-month (n=3, G) and 6-month (n=3, H) MCOs from SPAST WT/WT , SPAST WT/S245X and SPAST WT/C448Y lines, with or without Tub A treatment. HDAC6 activity is expressed as units (U) per mg of total protein, where one unit is defined as the amount of enzyme required to deacetylate 1pmol of a synthetic acetylated peptide substrate per minute. Elevated HDAC6 activity in mutant organoids is significantly reduced by Tub A treatment at both time points. I-J. WB (I) and quantification (J) of HDAC6 (black arrow) protein levels in 3-month MCOs derived from SPAST WT/WT , SPAST WT/S245X and SPAST WT/C448Y lines. HDAC6 expression, normalized to GAPDH and shown relative to SPAST WT/WT , revealed no significant differences across genotypes (n = 4). One-way ANOVA with Tukey post hoc analysis. *p<0.05, **p<0.002, ***p<0.001, ****p<0.0001. All data shown as mean ± SD, see Supplementary Tables 3-4 for details.
Article Snippet: HDAC6 activity assays were performed according to the manufacturer’s instructions (BPS Biosciences, 50076-1) and as previously described., Briefly, treated and untreated organoid samples, as well as spinal cord tissue samples, were lysed in HDCA6 lysis buffer and centrifuged at 16,000g for 10 mins at 4°C.
Techniques: Derivative Assay, Staining, Mutagenesis, Marker, Activity Assay, Expressing