ATF4 mediates LPS-induced MCP-1 production in mouse microvascular endothelial cells. A-D). Mouse retina endothelial cells were transduced with Ad-ATF4, Ad-ATF4DN, or Ad-Ctrl for 24 h and then treated with 250 ng/ml of LPS for extra 24 h. The levels of MCP-1 mRNA expression and protein secretion were measured by qPCR or ELISA, respectively. E). ATF4 +/+ or ATF4 −/− mouse brain endothelial cells were stimulated with 250 ng/ml of LPS for 8 h. MCP-1 secretion in the medium was evaluated by ELISA. F). ATF4+/+ mouse brain endothelial cells were transduced with Ad-Ctrl or Ad-ATF4 and then treated with 250 ng/ml of LPS for 8 h. MCP-1 secretion was measured by ELISA. Results were expressed as mean ± SD. * P < 0.05, ** P < 0.01, *** p < 0.001 vs. Ad-Ctrl; ++ P < 0.01, +++ P < 0.001 vs. WT + LPS or Ad-Ctrl + LPS.