CSF1/CSF1R-mediated Crosstalk Between Choroidal Vascular Endothelial Cells and Macrophages Promotes Choroidal Neovascularization

Abstract

Purpose This study examined the role of the CSF1/CSF1Raxis in the crosstalk between choroidal vascular endothelial cells (CVECs) and macrophages during the formation of choroidal neovascularization (CNV). Methods Quantitative reverse transcriptase (QRT)-PCR, Western blot and ELISA measured the production and release of CSF1 from human choroidal vascular endothelial cells (HCVECs) under hypoxic conditions. Western blot detected CSF1 released from HCVECs under hypoxic conditions that activated the PI3K/AKT/FOXO1 axis in human macrophages via binding to CSF1R. Transwell migration assay, qRT-PCR, and Western blot detected the effect of CSF1 released from HCVECs on macrophage migration and M2 polarization via the CSF1R/PI3K/AKT/FOXO1 pathway. Incorporation of 5-ethynyl-20-deoxyuridine, transwell migration, and tube formation assays detected the effects of CSF1/CSF1R on the behaviors of HCVECs. Fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), and immunofluorescence detected the effect of blockade of CSF1/CSF1R on mouse laser-induced CNV. Color fundus photograph, ICGA, and FFA detected CNV lesions in neovascular AMD (nAMD) patients. ELISA detected CSF1 and CSF1R in the aqueous humor of age-related cataract and nAMD patients. Results CSF1 released from HCVECs under hypoxic conditions activated the PI3K/AKT/FOXO1 axis in human macrophages via binding to CSF1R, promoting macrophage migration and M2 polarization via up-regulation of the CSF1R/PI3K/AKT/FOXO1 pathway. Human macrophages promoted the proliferation, migration, and tube formation of HCVECs in a CSF1/CSFR1-dependent manner under hypoxic conditions. CSF1/CSF1R blockade ameliorated the formation of mouse laser-induced CNV. CSF1 and CSF1R were increased in the aqueous humor of nAMD patients. Conclusions Our results affirmed the crucial role of CSF1/CSF1R in boosting the formation of CNV and offered potential molecular targets for the treatment of nAMD.

ceRNA network construction and identification of hub genes as novel therapeutic targets for age-related cataracts using bioinformatics

“…Conversely, another study ( Zhu et al, 2018 ) with different glucose concentrations showed that up-regulating FOXO1 can prevent HLECs from oxidative damage induced by high glucose via beta-casomorphin-7 treatment. FOXO1 is also associated with choroidal neovascularization, and retina vein occlusions have also been reported ( Chen et al, 2019 ; Zhou et al, 2021b ). However, there is a lack of research on the role of up-regulated FOXO1 in ARC pathogenesis.…”

Dendritic cells play no significant role in the laser-induced choroidal neovascularization model

“…The pharmacologic Flt3 inhibitor AC220 is specific at nanomolar levels, but the authors used 0.1–10 mg/ml (0.18–18 mM). At 6 orders of magnitude above specificity, AC220 has many off target effects including inhibition of platelet-derived growth factor receptors and colony stimulating factor 1 (Csf1) receptor 16 , which both can stimulate choroidal angiogenesis 17 – 19 . In addition, experiments in this prior publication were performed at 4–8 weeks of age, but the sex and genetic background of the Flt3 −/− mice were not reported.…”

“…However, Flt3 −/− mice can exhibit an enhanced response to Csf1, leading to DC development 20 . Since Csf1 expression increases after laser injury 19 , Csf1-dependent signaling is a possible compensatory mechanism for DC maturation in Flt3 −/− mice, explaining why Flt3 −/− mice have increased DCs after laser injury.…”

Role of macrophage in ocular neovascularization

“…CSF1-neutralizing antibodies increase the expression of the M1-type macrophage marker but decreased the expression of the M2-type marker. Moreover, CSF1/CSF1R also ameliorates laser-induced CNV formation in mice [ 78 ]. CSF1 released from HCVECs under hypoxic conditions is important for inducing macrophage M2 polarization and CNV formation.…”