Fig. 1.

CCL2 receptor mediated Ca²⁺ signalling is required for chemotaxis. (A) Representative Ca²⁺ transient evoked by CCL2 in Fluo-4-loaded THP-1 cells. (B) Relationship between peak Ca²⁺ response and CCL2 concentration in THP-1 cells (n = 3). (C) Effect of the selective CCR2 antagonist BMSCCR222 on peak Ca²⁺ response to 50 ng/ml CCL2 expressed as a percentage of control (no antagonists) in THP-1 cells (n = 3). (D) Representative trace showing effect of PTx (100 ng/ml) on CCL2-evoked Ca²⁺ responses in THP-1 cells (n = 3). (E) Representative trace showing effect of PLC inhibition with U73122 (5 µM) on CCL2-evoked Ca²⁺ responses in THP-1 cells (n = 4). (F) Transwell assays showing the effect of PTx (100 ng/ml), BMSCCR222 (BMS, 100 nM), U73122 (5 µM) and BAPTA-AM (100 µM) (all n = 3) on THP-1 migration towards CCL2 (50 ng/ml lower chamber, 2 h). Fluo-4 signals are normalised to the maximum Ca²⁺ response elicited by 40 µM digitonin. *P<0.01 (ANOVA) versus vehicle control. Data are presented as mean±s.e.m. All antagonists were pre-incubated for 30 min prior to agonist challenge.