GSE160011
Secreted phosphoprotein 1 expression in retinal mononuclear phagocytes links murine to human choroidal neovascularization
Neovascular age-related macular degeneration represents the most common cause of blindness in the western world. Alterations of the outer Blood-retina barrier integrity and a localized inflammatory microenvironment lead to sprouting of choroidal neovascularization in intimate contact with surrounding myeloid cells and ultimately lead to visual impairment. The discovery of novel targets interfering with angiogenesis and inflammation is vital for the future treatments in AMD patients. To identify novel potential targets in the local phagocytes of the retina, microglia, we performed a comprehensive RNA-seq analysis in the mouse model of laser-induced choroidal neovascularization (mCNV). Here, we identified the angiogenic factor Osteopontin (Opn), also known as "secreted phosphoprotein 1” (Spp1), to be one of the most highly expressed genes in retinal microglia in the course of CNV formation. We could confirm the presence of SPP1 at the lesion site in recruited retinal microglia of Cx3cr1CreER:Rosa26-Tomato reporter mice using immunohistochemistry and in whole retinal tissue lysates by ELISA compared to controls highlighting a massive local production of SPP1. Inhibition of SPP1 by intravitreal injection of anti-SPP1 antibody significantly increased the lesion size compared to IgG-treated control eyes. In line with the results in rodents, we found an increased SPP1 mRNA expression in surgically extracted human choroidal neovascular (hCNV) membranes by the quantitative RNA-seq approach of massive analysis of cDNA ends (MACE) and found numerous IBA1+SPP1+ myeloid cells in human CNV membranes. Taken together, these results highlight the importance of SPP1 in the formation of CNV and potentially offer new opportunities for therapeutic intervention by inhibiting the SPP1 pathway. Overall design: RNA sequencing of 6 laser samples (retinal microglia, mouse, laser CNV) and 6 unlasered controls.