Journal: Scientific Reports
Article Title: High-content analysis of proteostasis capacity in cellular models of amyotrophic lateral sclerosis (ALS)
doi: 10.1038/s41598-024-64366-0
Figure Lengend Snippet: Schematic of High Content Analysis (HCA) image processing and analysis optimisation. To analyse the fluorescence intensity of EGFP-/tGFP- and tdTomato (tdT)/mCherry-fusion proteins and quantify protein inclusions containing fluorescent fusion proteins in NSC-34 cells, we deployed the Spot Detector BioApplication designed to analyse fluorescent foci in cells. Optimisation was carried out using images of NSC-34 cells triple-transfected to express H2B-ECFP, either SOD1 WT -EGFP, SOD1 A4V -EGFP, TDP-43 WT -tGFP TDP-43 M337V -tGFP, FUS WT -tGFP, FUS R495X -tGFP, FUS R521G -tGFP or EGFP alone and mCherry alone. Cells were imaged at 48 h post-transfection using a 20 × objective lens. ( a ) Raw images from Channels 1 (H2B-ECFP), 2 (EGFP-/tGFP-fusion proteins) and 3 (tdT/mCherry-fusion proteins) were first pre-processed to remove background fluorescence, exclude cells positioned on the border of each image from analysis and distinguish individual cells (‘object’ segmentation). Channel 1 images were additionally smoothed (blurred) to help reduce fluorescent noise that could lead to the false inclusion of image artefacts in subsequent analyses. ( b ) Biological ‘objects’, in this case cells, were identified using nuclear-localised H2B-ECFP fluorescence in Channel 1 images. To select viable transfected cells for analysis and exclude image artefacts, dead cells and cell debris, cells were selected based on the size and fluorescence intensity of their ECFP-fluorescent nuclei. ( c ) The relevant measures for GFP fluorescence intensity and fluorescent foci were measured in Channel 2 within a circular analysis mask that expanded the mask derived in Channel 1. The green circular mask indicates cells selected for analysis, while yellow masks indicate fluorescent foci/‘spots’ selected for analysis. To detect and analyse fluorescent foci corresponding to protein inclusions, upper and lower limits for size and fluorescence intensity were set. ( d ) Channel 3 objects were identified using the same mask as Channel 2.
Article Snippet: Phase contrast and fluorescent images from 20 fields of view per well were acquired, with image analysis parameters optimised using the SpotDetector V4 BioApplication in HCS Studio (Thermo Scientific) summarised in Fig. (further detail in Figure ).
Techniques: High Content Screening, Fluorescence, Transfection, Derivative Assay