Fig. 1

TLQP-21 alters morphology, motility and phagocytosis of BV2 microglia. a, Schematic representation of the mouse VGF protein sequence showing TLQP-21 peptide (green), the inactivating amino acid substitution in the mutant TLQP-R21A (pink) and the C3 super-agonist C3aSA (blue). b, RT-qPCR quantification of CD11b, CD45, c-Fos and CXCL10 mRNA levels after 1 h of treatment with TLQP-21 or C3aSA (0 to 2.5 μM). n = 2–6 wells/group from one single culture experiment. A Kruskal-Wallis test followed by a Dunn’s multiple comparisons test was used. c, Representative images of BV2 cells immuno-labelled with antibodies directed against IBA1 (red) or CD68 (green), following treatment with TLQP-21 (1 μM). The histogram on the bottom-right represents a quantification of the fold-change of elongated BV2 cells following TLQP-21 treatment in comparison to control. n = 5–6 wells/group (with 3 photomicrographs per well and an average of 115 cells examined per photomicrograph) with N = 3 independent experiments (data presented are the average of all experiments). Scale bar = 50 μm. d, Representative photomicrographs of the wound healing assay performed on BV2 cells treated with TLQP-21, TLQP-R21A or C3aSA for 1 h before the scratch. A picture of the same area was taken for each well every hour for 6 h. The graphic on the right represents the number of invading cells in the scratch for each group and time. n = 5–6/wells/group (with 1 photomicrograph per well at the exact same position) and N = 3 independent experiments (data presented are the average of all experiments), a Two-Way ANOVA test followed by a Tukey’s multiple comparisons test was done. e, Representative images of the phagocytosis assay (in red: IBA1 immunostained BV2 cells; in green: fluorescent latex beads) performed on BV2 cells treated with TLQP-21, TLQP-R21A or C3aSA. The graphic on the right represents the percentage of phagocytosed latex beads compared to control. n = 18–24 images/group (from 3 to 4 wells/group) with N = 3 independent experiments (data presented are the average of all experiments), a One-Way ANOVA followed by a Tukey’s multiple comparisons test was done. Error bars represent means ± SEM. *p < 0.05, ***p < 0.001