Abstract
Purpose :
We have previously characterized the proteomic profile in the aqueous humor (AH) from AMD patients. Notably, Clusterin/ApoJ (CLU) protein levels were increased in AH from eyes with non-neovascular AMD (n-nAMD) compared with eyes with neovascular AMD (nAMD). Here we aim to evaluate for potential involvement of CLU in the pathogenesis of n-nAMD and nAMD.
Methods :
CLU potential effect in the context of nAMD was evaluated in mouse choroidal sprouting assay (CSA), and by intravitreal delivery of CLU in the mouse model of laser induced choroidal neovascularization (LI-CNV). Readouts included the choroidal sprouting area and the CNV area per isolectin staining of retinal pigmented epithelium-choroid flat mounts, respectively. CLU was also delivered intravitreally in the mouse model photic retinal injury to assess its potential role in n-nAMD. Readout included electroretinogram (ERG) seven days post-injury. The effect of CLU on mononuclear cell migration was evaluated in human monocyte-derived macrophages as a measure of its potential involvement in retinal inflammation.
Results :
A notable reduction in the mean (SD) choroidal sprouting area (mm^2) was observed when media from CLU-treated M2 macrophages was added to the culture (0.57 ±0.39), as compared with untreated M2 macrophages (1.09±0.79, p=0.024). Additionally, the CSA sprouting area was diminished following treatment with CLU (0.26±0.14 vs 0.46±0.21, p=0.0022). In the in vivo model of LI-CNV, the CNV area following intravitreal delivery of 10mg/ml CLU was smaller compared with the control mice (0.007±0.003 vs 0.012±0.006, p=0.033). In the model for photic retinal injury, ERG amplitudes (μV) were similar following CLU treatment (174.7±85.11) compared with controls (111.85±20.6, p=0.14). The migration assay indicated that CLU had no discernible impact on monocyte recruitment.
Conclusions :
CLU, which is upregulated in n-nAMD eyes, can suppress choroidal sprouting ex-vivo, and diminish CNV growth in mice model of LI-CNV. This effect may be mediated in part by macrophages. The potential role of CLU as an endogenic anti angiogenic factor in AMD should be further evaluated.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.