Fig. 3: Lasp1 regulates arthritic FLS migration and cell-to-cell contact dynamics.

a Cell migration of murine FLS from wt, Lasp1^−/−, hTNFtg and hTNFtg/Lasp1^−/− mice as determined by a modified scratch assay after 0 and 24 h (representative images of n ≥ 3 per group, scale bar: 100 µm). b Quantification of the migration speed in this modified scratch assay (n ≥ 3 each group). All data presented as mean ± SEM, *P < 0.05 (two-tailed Mann–Whitney U test). c Analysis of the proliferation rate of adhered FLS from wt, Lasp1^−/−, hTNFtg and hTNFtg/Lasp1^−/− mice as determined by the CyQuant^® Assay (n = 9 each group). All data presented as mean ± SEM, *P < 0.05, **P < 0.001, ***P < 0.0001 (two-tailed Mann–Whitney U test). d Exemplary analyses of live-cell imaging of cell migration of hTNFtg FLS and hTNFtg/Lasp1^−/− FLS in a modified scratch assay. The cell front was determined by edge detection and tracked over time. Linescan through front monitors front movement over time (graph hTNFtg FLS n = 18 linescans from 1 scratch assay; hTNFtg/Lasp1^−/− FLS n = 16 linescans from 1 scratch assay). The movies 1 and 2 are included in the Supplementary Data (scale bar: 100 µm). e Establishment of cell-to-cell contacts was analysed by electric cell/substrate impedance sensing (ECIS) and the total resistance reflecting the strength of cell-to-cell contacts was monitored over a time period of 26 h (representative measurement of n = 3 independent experiments). f Live-cell fluorescence imaging of FLS from hTNFtg and hTNFtg/Lasp1^−/− mice transduced with a lentiviral Life-Act-GFP construct. Imaging was performed for an hour with an image rate of two minutes (representative pictures of n = 3 per each group). The movies 3 and 4 are included in the Supplementary Data (scale bar: 10 µm). g Lamellipodial dynamics analysis. To quantify lamellipodia dynamics (from Fig. 3f), the extension-retraction behaviour was determined over time, and the difference in positive (left) and negative (right) displacement (hTNFtg FLS n = 3 reslices from 24 cells; hTNFtg/Lasp1^−/− FLS n = 3 reslices from 30 cells) was calculated. Source data are provided as a Source Data file.