Plasma membrane remodeling in GM2 gangliosidoses drives synaptic dysfunction
Fig 2
Neuronal maturation, GM2 quantification and the impact of GM2 accumulation on the whole cell proteome of Tay–Sachs and Sandhoff disease models.
A. qPCR analysis of gene expression for the stem cell marker OCT-4 and the neuronal marker synaptophysin (SYP) in SCRM and ΔHEXA-1 cell lines at 0 and 14 dpi. Fold change is calculated relative to 14 dpi SCRM controls, N = 3 biological replicates were carried out in technical triplicate n = 3 (squares, triangles, circles) and the mean is displayed (grey line). Significance was determined with a two-way ANOVA, ****p ≤ 0.0001. B. Quantification of whole-cell gangliosides at 14 dpi for SCRM, ΔHEXA and ΔHEXB cell lines, the mean of N = 3 biological replicates is displayed ± SEM. Significance was determined by two-way ANOVA, **p ≤ 0.01, ****p ≤ 0.0001. C. Quantitative whole cell proteomics (WCP) data for ΔHEXA-1/2 and ΔHEXB-1/2 neurons compared with the SCRM control. A volcano plot is shown with average fold change (x-axis) across N = 3 biological replicates and significance (y-axis, two-sided t test) across the three replicates. Endolysosomal proteins are colored in red with targets mentioned in the text labelled. D. Gene ontology (GO) term analysis for proteins significantly changed in the WCP dataset. Changes are shown for cellular component, molecular function and biological process with the change plotted as the false discovery rate (log10FDR) and the number of proteins in each group indicated. E. Select targets from the WCP are represented graphically to illustrate the fold change in whole cell protein abundance in ΔHEXA and ΔHEXB neurons vs. SCRM neurons. F. Schematic diagram of lysosomal exocytosis and how this process can contribute to changes in lipid and protein abundance at the plasma membrane (PM). A selection of lysosomal proteins increased in abundance in the WCP of ΔHEXA and ΔHEXB neurons are illustrated. Underlying data used to generate these figures are available in S1 Data at https://doi.org/10.17863/CAM.118836.