These data are consistent with our results, which demonstrate that the suppression of monocyte/macrophage infiltration acts as an important cellular mechanism for INCB3344 treatment in the current model. To determine the impact of INCB3344 on the downstream signaling of macrophages in CNV formation, we detected VEGF on the peak response day of macrophages. Our results demonstrated that VEGF significantly decreased with the suppression of infiltrating macrophages by INCB3344 treatment. After photocoagulation, VEGF is up-regulated, and acts as a promoting mediator in the development of CNV. The variation of VEGF levels correlates highly to that of macrophages after laser injury, and their peak responses are reported to coincide with each other. While in pharmacologically macrophage-depleted mice, VEGF production is reduced in proportion to the decrease in the number of macrophages. Moreover, enriched ocular-infiltrating macrophages from laser-induced model mice have shown angiogenic ability in a dorsal air sac assay, and express activation-surface markers and the mRNA for potential angiogenic factors including VEGF, which indicates that the infiltrating macrophages are a rich source of VEGF. Our results agree with these data and reveal that macrophages play an important role in the variation of intro-ocular VEGF after laser injury. Further more, our results demonstrate that elevated VEGF expression in infiltrating macrophages is suppressed by INCB3344. We reveal that INCB3344 can not only inhibit macrophage infiltration but also suppress the angiogenic ability of infiltrating macrophages, which results in the reduction of VEGF, and finally in suppression of CNV. In this study, we revealed that INCB3344 treatment inhibited CNV formation via the suppression of macrophage infiltration. Our study focused on CCR2, macrophages, and VEGF, although several other cytokines such as tumor necrosis factor-alpha –, interleukin -1beta, hypoxia inducible factors, IL-6 and tissue factor are reported to be involved in CNV formation. We cannot rule out a potential link between macrophages and other cytokines, however, VEGF is crucial in the pathogenesis of CNV formation because anti-VEGF drug therapy, for example, bevacizumab and ranibizumab have achieved an obvious effect in CNV due to age-related macular degeneration. We demonstrated that the ERK1/2 phosphorylation induced by laser treatment was significantly suppressed by INCB3344. We examined the phosphorylation of ERK 1/2 because the activation of ERK1/2 in macrophages can be induced through the CCR2 and their activation is thought to be a key component in the cellular events leading to the infiltration and activation of macrophages –. Our results are consistent with the results in vitro, and the Niltubacin previous reports that blockage of CCR2 by anti-CCR2 monoclonal antibodies inhibits phosphorylation of ERK1/2 in peritoneal macrophages. Our results on the inhibitory effect on VEGF secretion are also compatible with the data that ERK1/2 activation in macrophages or monocytes is reported to be responsible for VEGF production in these cells. We can conclude that INCB3344 inhibits the activation of ERK1/2 in macrophages by blocking CCR2, which results in the reduction of macrophage infiltration and VEGF production.