Oncostatin M Reduces Pathological Neovascularization in the Retina Through Müller Cell Activation

PURPOSE. Continuous vision loss due to vasoproliferative eye disease still represents an unsolved issue despite anti -vascular endothelial growth factor (VEGF) therapy. The impact of signal transducer and activator of transcription 3 (STAT3) signaling on retinal angiogenesis and its potential use as a therapeutic target remain controversial. In vitro, oncostatin M (OSM), as a strong STAT3 activator, possesses robust proangiogenic activity. This study investigated to what extent the proangiogenic effects of OSM translate to the in vivo setting of vasoproliferative eye disease. METHODS. The in vitro effect of OSM on endothelial cells was investigated in the spheroid sprouting assay and through RNA sequencing. The mouse model for oxygen -induced retinopathy (OIR) was used to evaluate the impact of OSM in vivo. Signaling patterns were measured by western blot and retinal cryosections. Primary Muller cell cultures were used to evaluate the effect of OSM on the Muller cell secretome. Murine retinal vascular endothelial cells were isolated from OIR retinas using fluorescence -activated cell sorting (FACS) and were used for RNA sequencing. RESULTS. Although OSM induced pro-angiogenic responses in vitro, in the OIR model intravitreal injection of OSM reduced retinal neovascularization by 65.2% and vaso-obliteration by 45.5% in Muller cells. Injecting OSM into the vitreous activated the STAT3 signaling pathway in multiple retinal cell types, including Muller cells. In vitro, OSM treatment increased CXCL10 secretion. RNA sequencing of sorted vascular endothelial cells at OIR P17 following OSM treatment indicated downregulation of angiogenesisand mitosis -associated genes. CONCLUSIONS. In vivo, OSM reveals a beneficial angiomodulatory effect by activating Muller cells and changing their secretome. The data highlight contradictions between cytokineinduced effects in vitro and in vivo depending on the cell types mediating the effect.