C1 acts as a chemoattractant but did not influence microglial motility and phagocytosis.

a) C1 affected microglial chemotaxis. The results were normalized to ATP induced (black bars) chemotaxis or motility, respectively. A gradient of 2.5 μM C1 (in red) increased chemotaxis significantly compared to plain medium (in white, p = 0.0036) and DMSO (in grey, p = 0.0012). 2.5 μM C1 did not affect ATP induced chemotaxis in microglia. b) C1 (in red) significantly decreased microglial motility when compared to plain medium (white, p = 0.0018) but not to DMSO (grey). ATP induced motility did not change in the presence of C1 or DMSO. *** pc) The phagocytic activity both under basal conditions (left, ctrl.) and LPS stimulated conditions (right, +LPS) was assessed using a FACS-based protocol. Microglia were pre-treated with 2.5 μM C1 in DMSO (red) or its corresponding concentration of DMSO (in grey,125x10-5 v/v) and compared to the control medium. Neither C1 nor DMSO altered microglial phagocytosis significantly compared to plain medium (white). Upon stimulation with 1 μg/mL LPS for 24 hours phagocytosis increased significantly around 60% compared to their own unstimulated control (plain medium: +55% p = 0.0066, DMSO: +67% p = 0.0068, C1: +45% p = 0.0163, black striped bars). Within LPS stimulated conditions there were no significant differences. *** p<0.001 ** p<0.01 compared to plain medium control (non-matching 2way ANOVA followed by Sidak test).