Figure 3.

Loss of Olfml3 impairs microglial phagocytosis and chemotaxis. (A) There were no morphological differences detected between isogenic control and Olfml3^-/- microglia; scale bar 5 µm. (B) Cellular viability, as assayed by Cell Titer-Glo^® (p = 0.53) and MTS (p = 0.27) assays, was not altered following deletion of Olfml3 in N9 microglia. (C) Microglial phagocytosis of pHrodo^TM Escherichia coli bioparticles was reduced by 30% in Olfml3^-/- microglia relative to isogenic control cells. Comparisons based on students t-test; ** p < 0.01. (D) Representative images of isogenic control and Olfml3^-/- microglial migration toward fetal bovine serum (FBS; 10%) or human recombinant C-C motif chemokine ligand 2 (rhCCL2; 10 ng/mL); scale bar 20 µm. (E) Loss of Olfml3 markedly attenuated microglial migration toward FBS relative to isogenic control cells. Comparisons based on students t-test; *** p < 0.001. (F) The rhCCL2 elicited equivalent chemotaxis between isogenic control and Olfml3^-/- N9 cells. Comparisons based on students t-test; p = 0.54. (G) Chemotaxis toward ATP (50 µM, 100 µM) increased relative to vehicle in isogenic control, but not Olfml3^-/-, microglia. Comparisons based on one-way ANOVA with Tukey’s Multiple Comparison Test; *** p < 0.001. Bars represent group mean with standard error of the mean (SEM); data represent one of three independent experiments.