Effects of CX3CL1 and CCL2 on the expressions of angiogenesis-related factors of human monocyte-derived macrophages / 中华实验眼科杂志

ABSTRACT

Background Intracorneal macrophages play a critical role in corneal neovascularization (CNV)by secreting relative chemokines.But macrophages are characteristic by heterogeneity which has different biologic functions under different induction or stimulation from microenvironment.Objective This study was to detect the effects of chemokine (C-X3-C motif) ligand 1 (CX3CL1) and chemokine (C-C motif) ligand 2 (CCL2) on macrophages in vitro.Methods CNV was induced by corneal alkali burn in the left eyes of 20 male BALB/c mice aged 7-8 weeks.The CNV was evaluated under the slit lamp microscope 4 days after alkali burn,and then the corneal sections were prepared after mice were sacrificed.The expressions of CCR2 and CX3CR1 in the corneal specimens were detected by histo-fluorescence staining.Human peripheral blood mononuclear cells were separated using density gradient centrifugation and incubated in RPMI-1640 medium containing 10％ fetal bovine seruml(FBS) with 30 μg/L granulocyte-macrophage colony-stimulating factor (GM-CSF).The cells were divided into CD68 +CCR2 group and CD68+CX3CR1 group,and the percentage of the CX3CR1 and CCR2 expressions in the infiltrated macrophages of corneal specimens and human monocyte-derived macrophages was assayed by flow cytometry.The cultured cells were stimulated using human recombinant CX3CL1 and CCL2 proteins,and real-time PCR was used to detect the relative expressions of angiogenesis-related factors in macrophages.Results CNV was found in corneas 4 days after alkali burn and the CNV onsets from corneal limbus to central zone observed by a slit lamp.CCR2 and CX3CR1 were expressed in the F4/80-positive macrophages in alikali burned corneas.The macrophages grew for two weeks and appeared more dead cells in without GM-CSF group,but in GM-CSF induced group,the number of macrophages was increased.The percentage of CX3CR1-positive cells was 75％ and that of CCR2-positive cells was 45％.Real-time PCR showed that expression level of vascular endothelial growth factor (VEGF) mRNA increased and that ADAMTS-1 mRNA or TSP-1 mRNA decreased on macrophages after CCL2 stimulation,with significant differences in the 150 mg/L CCL2 group compared with the control group (t =-5.09,P =0.03 ; t =3.01,P =0.04 ; t =4.27,P =0.02).However,the VEGF mRNA expression decreased and ADAMTS-1 mRNA and TSP-1 mRNA increased after CX3CL1 stimulation,showing significant differences between the 150 mg/L CX3CL1 group and the control group (t=6.35,P=0.O2;t=-2.92,P=0.04; t=-3.81,P=0.03).Conclusions These results suggest that the macrophages have high heterogeneity.CCL2-and CX3CL1-expressing macrophages can regulate the expressions of angiogenesis-related factors.Macrophage chemokine signal may be a good target for treatment of neovascular ocular disease.