Journal: Cell reports
Article Title: Modeling spastic paraplegia 4 with corticospinal motor neuron-enriched cortical organoids reveals genotype-phenotype and HDAC6-targetable pathology
doi: 10.1016/j.celrep.2026.117036
Figure Lengend Snippet: (A) Representative immunofluorescence images of 3- and 6-month CSMN-COs 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 and C) Quantification of the acetylated tubulin-to-βIII-tubulin ratio in 3-month (B) and 6-month (C) CSMN-COs ( n = 3–6). Tub A significantly increased tubulin acetylation in mutant CSMN-COs. (D) Representative immunofluorescence images of 3- and 6-month-old CSMN-COs from SPAST WT/WT , SPAST WT/S245X , and SPAST WT/C448Y lines, untreated or treated with Tub A, and 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)) CSMN-COs. 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)) CSMN-COs 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 1 pmol 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 CSMN-COs 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, and unpaired t test. ## p < 0.005, ### p < 0.001. All data shown as mean ± SD; see and for details.
Article Snippet: HDAC6 Fluorogenic Assay , BPS Biosciences , 50076–1.
Techniques: Immunofluorescence, Derivative Assay, Staining, Mutagenesis, Marker, Activity Assay, Expressing