Fig. S1. MCP1 mutants were non-toxic to mouse BMECs or HBMECs. Mouse BMECs or HBMECs were treated with MCP1 mutants or saline for 24 hours. Media were collected and used for LDH assays. (A) Cytotoxicity of MCP1 mutants to mouse BMECs. (B) Cytotoxicity of MCP1 mutants to HBMECs. Data are shown as means±s.d. (n=3).

Fig. S2. Truncated MCP1 compromises BBB integrity. 100 nM MCP1 was added to the lower chamber of the BMEC-astrocyte co-culture system. FITC−Dextran was added to the upper chamber of the co-culture system. In the presence of A2AP, the leakage of FITC−Dextran across the co-culture system was determined by quantifying the fluorescence intensity in the lower chamber. Values are means±s.d. (n=3). *P<0.05 compared with FL-MCP (analysis was performed by using Student's t-test).

Fig. S3. Dose-dependent effect of FL- and K104Stop-MCP1. 10, 50, 100 nM FL- and K104Stop-MCP1 were added to the lower chamber of the BMEC-astrocyte co-culture system. FITC−Dextran was added to the upper chamber of the co-culture system. After 1 hour, the leakage of FITC−Dextran across the co-culture system was determined by quantifying the fluorescence intensity in the lower chamber. Values are means±s.d. (n=3). *P<0.05 compared with FL-MCP (analysis was performed by using Student's t-test).